Programs & Examples On #Rvalue

An rvalue is a temporary object (or subobject) or is a value not directly associated with an object.

Use NSInteger as array index

According to the error message, you declared myLoc as a pointer to an NSInteger (NSInteger *myLoc) rather than an actual NSInteger (NSInteger myLoc). It needs to be the latter.

How to POST using HTTPclient content type = application/x-www-form-urlencoded

I was using a .Net Core 2.1 API with the [FromBody] attribute and I had to use the following solution to successfully Post to it:

_apiClient =  new HttpClient();
_apiClient.BaseAddress = new Uri(<YOUR API>);
var MyObject myObject = new MyObject(){
    FirstName = "Me",
    LastName = "Myself"
};

var stringified = JsonConvert.SerializeObject(myObject);
var result = await _apiClient.PostAsync("api/appusers", new StringContent(stringified, Encoding.UTF8, "application/json"));

Return file in ASP.Net Core Web API

Here is a simplistic example of streaming a file:

using System.IO;
using Microsoft.AspNetCore.Mvc;
[HttpGet("{id}")]
public async Task<FileStreamResult> Download(int id)
{
    var path = "<Get the file path using the ID>";
    var stream = File.OpenRead(path);
    return new FileStreamResult(stream, "application/octet-stream");
}

Note:

Be sure to use FileStreamResult from Microsoft.AspNetCore.Mvc and not from System.Web.Mvc.

Changing PowerShell's default output encoding to UTF-8

To be short, use:

write-output "your text" | out-file -append -encoding utf8 "filename"

How to pass boolean parameter value in pipeline to downstream jobs?

Assuming

value: update_composer

was the issue, try

value: Boolean.valueOf(update_composer)

is there a less cumbersome way in which I can just pass ALL the pipeline parameters to the downstream job

Not that I know of, at least not without using Jenkins API calls and disabling the Groovy sandbox.

Custom header to HttpClient request

There is a Headers property in the HttpRequestMessage class. You can add custom headers there, which will be sent with each HTTP request. The DefaultRequestHeaders in the HttpClient class, on the other hand, sets headers to be sent with each request sent using that client object, hence the name Default Request Headers.

Hope this makes things more clear, at least for someone seeing this answer in future.

How to use a client certificate to authenticate and authorize in a Web API

Looking at the source code I also think there must be some issue with the private key.

What it is doing is actually to check if the certificate that is passed is of type X509Certificate2 and if it has the private key.

If it doesn't find the private key it tries to find the certificate in the CurrentUser store and then in the LocalMachine store. If it finds the certificate it checks if the private key is present.

(see source code from class SecureChannnel, method EnsurePrivateKey)

So depending on which file you imported (.cer - without private key or .pfx - with private key) and on which store it might not find the right one and Request.ClientCertificate won't be populated.

You can activate Network Tracing to try to debug this. It will give you output like this:

  • Trying to find a matching certificate in the certificate store
  • Cannot find the certificate in either the LocalMachine store or the CurrentUser store.

Firebase TIMESTAMP to date and Time

In fact, it only work to me when used

firebase.database.ServerValue.TIMESTAMP

With one 'database' more on namespace.

How to add a recyclerView inside another recyclerView

you can use LayoutInflater to inflate your dynamic data as a layout file.

UPDATE : first create a LinearLayout inside your CardView's layout and assign an ID for it. after that create a layout file that you want to inflate. at last in your onBindViewHolder method in your "RAdaper" class. write these codes :

  mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

  view = mInflater.inflate(R.layout.my_list_custom_row, parent, false);

after that you can initialize data and ClickListeners with your RAdapter Data. hope it helps.

this and this may useful :)

How to use select/option/NgFor on an array of objects in Angular2

I'm no expert with DOM or Javascript/Typescript but I think that the DOM-Tags can't handle real javascript object somehow. But putting the whole object in as a string and parsing it back to an Object/JSON worked for me:

interface TestObject {
  name:string;
  value:number;
}

@Component({
  selector: 'app',
  template: `
      <h4>Select Object via 2-way binding</h4>

      <select [ngModel]="selectedObject | json" (ngModelChange)="updateSelectedValue($event)">
        <option *ngFor="#o of objArray" [value]="o | json" >{{o.name}}</option>
      </select>

      <h4>You selected:</h4> {{selectedObject }}
  `,
  directives: [FORM_DIRECTIVES]
})
export class App {
  objArray:TestObject[];
  selectedObject:TestObject;
  constructor(){
    this.objArray = [{name: 'foo', value: 1}, {name: 'bar', value: 1}];
    this.selectedObject = this.objArray[1];
  }
  updateSelectedValue(event:string): void{
    this.selectedObject = JSON.parse(event);
  }
}

Mockito - NullpointerException when stubbing Method

When using JUnit 5 or above. You have to inject the class annotated with @Mock in an @BeforeEach setup.

filter out multiple criteria using excel vba

I don't have found any solution on Internet, so I have implemented one.

The Autofilter code with criteria is then

iColNumber = 1
Dim aFilterValueArray() As Variant
Call ConstructFilterValueArray(aFilterValueArray, iColNumber, Array("A", "B", "C"))

ActiveSheet.range(sRange).AutoFilter Field:=iColNumber _
    , Criteria1:=aFilterValueArray _
    , Operator:=xlFilterValues

In fact, the ConstructFilterValueArray() method (not function) get all distinct values that it found in a specific column and remove all values present in last argument.

The VBA code of this method is

'************************************************************
'* ConstructFilterValueArray()
'************************************************************

Sub ConstructFilterValueArray(a() As Variant, iCol As Integer, aRemoveArray As Variant)

    Dim aValue As New Collection
    Call GetDistinctColumnValue(aValue, iCol)
    Call RemoveValueList(aValue, aRemoveArray)
    Call CollectionToArray(a, aValue)

End Sub

'************************************************************
'* GetDistinctColumnValue()
'************************************************************

Sub GetDistinctColumnValue(ByRef aValue As Collection, iCol As Integer)

    Dim sValue As String

    iEmptyValueCount = 0
    iLastRow = ActiveSheet.UsedRange.Rows.Count

    Dim oSheet: Set oSheet = Sheets("X")

    Sheets("Data")
        .range(Cells(1, iCol), Cells(iLastRow, iCol)) _
            .AdvancedFilter Action:=xlFilterCopy _
                          , CopyToRange:=oSheet.range("A1") _
                          , Unique:=True

    iRow = 2
    Do While True
        sValue = Trim(oSheet.Cells(iRow, 1))
        If sValue = "" Then
            If iEmptyValueCount > 0 Then
                Exit Do
            End If
            iEmptyValueCount = iEmptyValueCount + 1
        End If

        aValue.Add sValue
        iRow = iRow + 1
    Loop

End Sub

'************************************************************
'* RemoveValueList()
'************************************************************

Sub RemoveValueList(ByRef aValue As Collection, aRemoveArray As Variant)

    For i = LBound(aRemoveArray) To UBound(aRemoveArray)
        sValue = aRemoveArray(i)
        iMax = aValue.Count
        For j = iMax To 0 Step -1
            If aValue(j) = sValue Then
                aValue.Remove (j)
                Exit For
            End If
        Next j
     Next i

End Sub

'************************************************************
'* CollectionToArray()
'************************************************************

Sub CollectionToArray(a() As Variant, c As Collection)

    iSize = c.Count - 1
    ReDim a(iSize)

    For i = 0 To iSize
        a(i) = c.Item(i + 1)
    Next

End Sub

This code can certainly be improved in returning an Array of String but working with Array in VBA is not easy.

CAUTION: this code work only if you define a sheet named X because CopyToRange parameter used in AdvancedFilter() need an Excel Range !

It's a shame that Microfsoft doesn't have implemented this solution in adding simply a new enum as xlNotFilterValues ! ... or xlRegexMatch !

Command failed due to signal: Segmentation fault: 11

If you're using multiple versions of XCode, this error can easily happen if your paths have changed (eg. You downloaded the DMG to Desktop, extracted, but then moved XCode to Applications afterward). Carefully read the Segmentation Fault 11 error given to you in XCode, it may reference your old path which is the cause of the Segmentation Fault. If it does, you can fix it by either:

  1. xcode-select the correct path. Eg. sudo xcode-select -s /Applications/Xcode-beta.app/Contents/Developer/ (obviously input your correct path here)
  2. When installing your second version of XCode, ensure it's being extracted to the final path (extract to Applications itself) and that 'XCode.app' doesn't already exist when you do so (rename your previous one if it exists). After it's installed, you can rename both as you like.

Another potential fix for this issue:

Upgrading from El Capitan to Sierra and 'installing extra components' when launching Xcode after this upgrade fixed it for me the first time this happened.

How to return a file (FileContentResult) in ASP.NET WebAPI

If you want to return IHttpActionResult you can do it like this:

[HttpGet]
public IHttpActionResult Test()
{
    var stream = new MemoryStream();

    var result = new HttpResponseMessage(HttpStatusCode.OK)
    {
        Content = new ByteArrayContent(stream.GetBuffer())
    };
    result.Content.Headers.ContentDisposition = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment")
    {
        FileName = "test.pdf"
    };
    result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");

    var response = ResponseMessage(result);

    return response;
}

Pass multiple complex objects to a post/put Web API method

You could try posting multipart content from the client like this:

 using (var httpClient = new HttpClient())
{
    var uri = new Uri("http://example.com/api/controller"));

    using (var formData = new MultipartFormDataContent())
    {
        //add content to form data
        formData.Add(new StringContent(JsonConvert.SerializeObject(content)), "Content");

        //add config to form data
        formData.Add(new StringContent(JsonConvert.SerializeObject(config)), "Config");

        var response = httpClient.PostAsync(uri, formData);
        response.Wait();

        if (!response.Result.IsSuccessStatusCode)
        {
            //error handling code goes here
        }
    }
}

On the server side you could read the the content like this:

public async Task<HttpResponseMessage> Post()
{
    //make sure the post we have contains multi-part data
    if (!Request.Content.IsMimeMultipartContent())
    {
        throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
    }

    //read data
    var provider = new MultipartMemoryStreamProvider();
    await Request.Content.ReadAsMultipartAsync(provider);

    //declare backup file summary and file data vars
    var content = new Content();
    var config = new Config();

    //iterate over contents to get Content and Config
    foreach (var requestContents in provider.Contents)
    {
        if (requestContents.Headers.ContentDisposition.Name == "Content")
        {
            content = JsonConvert.DeserializeObject<Content>(requestContents.ReadAsStringAsync().Result);
        }
        else if (requestContents.Headers.ContentDisposition.Name == "Config")
        {
            config = JsonConvert.DeserializeObject<Config>(requestContents.ReadAsStringAsync().Result);
        }
    }

    //do something here with the content and config and set success flag
    var success = true;

    //indicate to caller if this was successful
    HttpResponseMessage result = Request.CreateResponse(success ? HttpStatusCode.OK : HttpStatusCode.InternalServerError, success);
    return result;

}

}

Download file from an ASP.NET Web API method using AngularJS

Support for downloading binary files in using ajax is not great, it is very much still under development as working drafts.

Simple download method:

You can have the browser download the requested file simply by using the code below, and this is supported in all browsers, and will obviously trigger the WebApi request just the same.

$scope.downloadFile = function(downloadPath) { 
    window.open(downloadPath, '_blank', '');  
}

Ajax binary download method:

Using ajax to download the binary file can be done in some browsers and below is an implementation that will work in the latest flavours of Chrome, Internet Explorer, FireFox and Safari.

It uses an arraybuffer response type, which is then converted into a JavaScript blob, which is then either presented to save using the saveBlob method - though this is only currently present in Internet Explorer - or turned into a blob data URL which is opened by the browser, triggering the download dialog if the mime type is supported for viewing in the browser.

Internet Explorer 11 Support (Fixed)

Note: Internet Explorer 11 did not like using the msSaveBlob function if it had been aliased - perhaps a security feature, but more likely a flaw, So using var saveBlob = navigator.msSaveBlob || navigator.webkitSaveBlob ... etc. to determine the available saveBlob support caused an exception; hence why the code below now tests for navigator.msSaveBlob separately. Thanks? Microsoft

// Based on an implementation here: web.student.tuwien.ac.at/~e0427417/jsdownload.html
$scope.downloadFile = function(httpPath) {
    // Use an arraybuffer
    $http.get(httpPath, { responseType: 'arraybuffer' })
    .success( function(data, status, headers) {

        var octetStreamMime = 'application/octet-stream';
        var success = false;

        // Get the headers
        headers = headers();

        // Get the filename from the x-filename header or default to "download.bin"
        var filename = headers['x-filename'] || 'download.bin';

        // Determine the content type from the header or default to "application/octet-stream"
        var contentType = headers['content-type'] || octetStreamMime;

        try
        {
            // Try using msSaveBlob if supported
            console.log("Trying saveBlob method ...");
            var blob = new Blob([data], { type: contentType });
            if(navigator.msSaveBlob)
                navigator.msSaveBlob(blob, filename);
            else {
                // Try using other saveBlob implementations, if available
                var saveBlob = navigator.webkitSaveBlob || navigator.mozSaveBlob || navigator.saveBlob;
                if(saveBlob === undefined) throw "Not supported";
                saveBlob(blob, filename);
            }
            console.log("saveBlob succeeded");
            success = true;
        } catch(ex)
        {
            console.log("saveBlob method failed with the following exception:");
            console.log(ex);
        }

        if(!success)
        {
            // Get the blob url creator
            var urlCreator = window.URL || window.webkitURL || window.mozURL || window.msURL;
            if(urlCreator)
            {
                // Try to use a download link
                var link = document.createElement('a');
                if('download' in link)
                {
                    // Try to simulate a click
                    try
                    {
                        // Prepare a blob URL
                        console.log("Trying download link method with simulated click ...");
                        var blob = new Blob([data], { type: contentType });
                        var url = urlCreator.createObjectURL(blob);
                        link.setAttribute('href', url);

                        // Set the download attribute (Supported in Chrome 14+ / Firefox 20+)
                        link.setAttribute("download", filename);

                        // Simulate clicking the download link
                        var event = document.createEvent('MouseEvents');
                        event.initMouseEvent('click', true, true, window, 1, 0, 0, 0, 0, false, false, false, false, 0, null);
                        link.dispatchEvent(event);
                        console.log("Download link method with simulated click succeeded");
                        success = true;

                    } catch(ex) {
                        console.log("Download link method with simulated click failed with the following exception:");
                        console.log(ex);
                    }
                }

                if(!success)
                {
                    // Fallback to window.location method
                    try
                    {
                        // Prepare a blob URL
                        // Use application/octet-stream when using window.location to force download
                        console.log("Trying download link method with window.location ...");
                        var blob = new Blob([data], { type: octetStreamMime });
                        var url = urlCreator.createObjectURL(blob);
                        window.location = url;
                        console.log("Download link method with window.location succeeded");
                        success = true;
                    } catch(ex) {
                        console.log("Download link method with window.location failed with the following exception:");
                        console.log(ex);
                    }
                }

            }
        }

        if(!success)
        {
            // Fallback to window.open method
            console.log("No methods worked for saving the arraybuffer, using last resort window.open");
            window.open(httpPath, '_blank', '');
        }
    })
    .error(function(data, status) {
        console.log("Request failed with status: " + status);

        // Optionally write the error out to scope
        $scope.errorDetails = "Request failed with status: " + status;
    });
};

Usage:

var downloadPath = "/files/instructions.pdf";
$scope.downloadFile(downloadPath);

Notes:

You should modify your WebApi method to return the following headers:

  • I have used the x-filename header to send the filename. This is a custom header for convenience, you could however extract the filename from the content-disposition header using regular expressions.

  • You should set the content-type mime header for your response too, so the browser knows the data format.

I hope this helps.

Get integer value from string in swift

above answer didnt help me as my string value was "700.00"

with Swift 2.2 this works for me

let myString = "700.00"
let myInt = (myString as NSString).integerValue

I passed myInt to NSFormatterClass

let formatter = NSNumberFormatter()
formatter.numberStyle = .CurrencyStyle
formatter.maximumFractionDigits = 0

let priceValue = formatter.stringFromNumber(myInt!)!

//Now priceValue is ? 700

Thanks to this blog post.

Name [jdbc/mydb] is not bound in this Context

you put resource-ref in the description tag in web.xml

Make Https call using HttpClient

Add the below declarations to your class:

public const SslProtocols _Tls12 = (SslProtocols)0x00000C00;
public const SecurityProtocolType Tls12 = (SecurityProtocolType)_Tls12;

After:

var client = new HttpClient();

And:

ServicePointManager.SecurityProtocol = Tls12;
System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 /*| SecurityProtocolType.Tls */| Tls12;

Happy? :)

"Templates can be used only with field access, property access, single-dimension array index, or single-parameter custom indexer expressions" error

I ran into a similar problem with the same error message using following code:

@Html.DisplayFor(model => model.EndDate.Value.ToShortDateString())

I found a good answer here

Turns out you can decorate the property in your model with a displayformat then apply a dataformatstring.

Be sure to import the following lib into your model:

using System.ComponentModel.DataAnnotations;

download csv file from web api in angular js

I used the below solution and it worked for me.

_x000D_
_x000D_
 if (window.navigator.msSaveOrOpenBlob) {_x000D_
   var blob = new Blob([decodeURIComponent(encodeURI(result.data))], {_x000D_
     type: "text/csv;charset=utf-8;"_x000D_
   });_x000D_
   navigator.msSaveBlob(blob, 'filename.csv');_x000D_
 } else {_x000D_
   var a = document.createElement('a');_x000D_
   a.href = 'data:attachment/csv;charset=utf-8,' + encodeURI(result.data);_x000D_
   a.target = '_blank';_x000D_
   a.download = 'filename.csv';_x000D_
   document.body.appendChild(a);_x000D_
   a.click();_x000D_
 }
_x000D_
_x000D_
_x000D_

Proper way to return JSON using node or Express

If you're using Express, you can use this:

res.setHeader('Content-Type', 'application/json');
res.send(JSON.stringify({key:"value"}));

or just this

res.json({key:"value"});

Web API Put Request generates an Http 405 Method Not Allowed error

Decorating one of the action params with [FromBody] solved the issue for me:

public async Task<IHttpActionResult> SetAmountOnEntry(string id, [FromBody]int amount)

However ASP.NET would infer it correctly if complex object was used in the method parameter:

public async Task<IHttpActionResult> UpdateEntry(string id, MyEntry entry)

HttpClient not supporting PostAsJsonAsync method C#

Try to install in your project the NuGet Package: Microsoft.AspNet.WebApi.Client:

Install-Package Microsoft.AspNet.WebApi.Client

How do I set up HttpContent for my HttpClient PostAsync second parameter?

This is answered in some of the answers to Can't find how to use HttpContent as well as in this blog post.

In summary, you can't directly set up an instance of HttpContent because it is an abstract class. You need to use one the classes derived from it depending on your need. Most likely StringContent, which lets you set the string value of the response, the encoding, and the media type in the constructor. See: http://msdn.microsoft.com/en-us/library/system.net.http.stringcontent.aspx

OR operator in switch-case?

Switch is not same as if-else-if.

Switch is used when there is one expression that gets evaluated to a value and that value can be one of predefined set of values. If you need to perform multiple boolean / comparions operations run-time then if-else-if needs to be used.

SQL Server : Columns to Rows

You can use the UNPIVOT function to convert the columns into rows:

select id, entityId,
  indicatorname,
  indicatorvalue
from yourtable
unpivot
(
  indicatorvalue
  for indicatorname in (Indicator1, Indicator2, Indicator3)
) unpiv;

Note, the datatypes of the columns you are unpivoting must be the same so you might have to convert the datatypes prior to applying the unpivot.

You could also use CROSS APPLY with UNION ALL to convert the columns:

select id, entityid,
  indicatorname,
  indicatorvalue
from yourtable
cross apply
(
  select 'Indicator1', Indicator1 union all
  select 'Indicator2', Indicator2 union all
  select 'Indicator3', Indicator3 union all
  select 'Indicator4', Indicator4 
) c (indicatorname, indicatorvalue);

Depending on your version of SQL Server you could even use CROSS APPLY with the VALUES clause:

select id, entityid,
  indicatorname,
  indicatorvalue
from yourtable
cross apply
(
  values
  ('Indicator1', Indicator1),
  ('Indicator2', Indicator2),
  ('Indicator3', Indicator3),
  ('Indicator4', Indicator4)
) c (indicatorname, indicatorvalue);

Finally, if you have 150 columns to unpivot and you don't want to hard-code the entire query, then you could generate the sql statement using dynamic SQL:

DECLARE @colsUnpivot AS NVARCHAR(MAX),
   @query  AS NVARCHAR(MAX)

select @colsUnpivot 
  = stuff((select ','+quotename(C.column_name)
           from information_schema.columns as C
           where C.table_name = 'yourtable' and
                 C.column_name like 'Indicator%'
           for xml path('')), 1, 1, '')

set @query 
  = 'select id, entityId,
        indicatorname,
        indicatorvalue
     from yourtable
     unpivot
     (
        indicatorvalue
        for indicatorname in ('+ @colsunpivot +')
     ) u'

exec sp_executesql @query;

Add two textbox values and display the sum in a third textbox automatically

well I think the problem solved this below code works:

function sum() {
    var result=0;
       var txtFirstNumberValue = document.getElementById('txt1').value;
       var txtSecondNumberValue = document.getElementById('txt2').value;
    if (txtFirstNumberValue !="" && txtSecondNumberValue ==""){
        result = parseInt(txtFirstNumberValue);
    }else if(txtFirstNumberValue == "" && txtSecondNumberValue != ""){
        result= parseInt(txtSecondNumberValue);
    }else if (txtSecondNumberValue != "" && txtFirstNumberValue != ""){
        result = parseInt(txtFirstNumberValue) + parseInt(txtSecondNumberValue);
    }
       if (!isNaN(result)) {
           document.getElementById('txt3').value = result;
       }
   }

scroll up and down a div on button click using jquery

scrollBottom is not a method in jQuery.

UPDATED DEMO - http://jsfiddle.net/xEFq5/10/

Try this:

   $("#upClick").on("click" ,function(){
     scrolled=scrolled-300;
        $(".cover").animate({
          scrollTop:  scrolled
     });
   });

AngularJS ngClass conditional

Using function with ng-class is a good option when someone has to run complex logic to decide the appropriate CSS class.

http://jsfiddle.net/ms403Ly8/2/

HTML:

<div ng-app>
  <div ng-controller="testCtrl">
        <div ng-class="getCSSClass()">Testing ng-class using function</div>       
    </div>
</div>

CSS:

.testclass { Background: lightBlue}

JavaScript:

function testCtrl($scope) {
    $scope.getCSSClass = function() {
     return "testclass ";
  }     
}

iterate through a map in javascript

The callback to $.each() is passed the property name and the value, in that order. You're therefore trying to iterate over the property names in the inner call to $.each(). I think you want:

$.each(myMap, function (i, val) {
  $.each(val, function(innerKey, innerValue) {
    // ...
  });
});

In the inner loop, given an object like your map, the values are arrays. That's OK, but note that the "innerKey" values will all be numbers.

edit — Now once that's straightened out, here's the next problem:

    setTimeout(function () {

      // ...

    }, i * 6000);

The first time through that loop, "i" will be the string "partnr1". Thus, that multiplication attempt will result in a NaN. You can keep an external counter to keep track of the property count of the outer map:

var pcount = 1;
$.each(myMap, function(i, val) {
  $.each(val, function(innerKey, innerValue) {
    setTimeout(function() {
      // ...
    }, pcount++ * 6000);
  });
});

Convert character to ASCII numeric value in java

Or you can use Stream API for 1 character or a String starting in Java 1.8:

public class ASCIIConversion {
    public static void main(String[] args) {
        String text = "adskjfhqewrilfgherqifvehwqfjklsdbnf";
        text.chars()
                .forEach(System.out::println);
    }
}

How to sum the values of a JavaScript object?

_x000D_
_x000D_
let prices = {_x000D_
  "apple": 100,_x000D_
  "banana": 300,_x000D_
  "orange": 250_x000D_
};_x000D_
_x000D_
let sum = 0;_x000D_
for (let price of Object.values(prices)) {_x000D_
  sum += price;_x000D_
}_x000D_
_x000D_
alert(sum)
_x000D_
_x000D_
_x000D_

Change Text Color of Selected Option in a Select Box

You could do it like this.

jsFiddle

JS

var select = document.getElementById('mySelect');
select.onchange = function () {
    select.className = this.options[this.selectedIndex].className;
}

CSS

.redText {
    background-color:#F00;
}
.greenText {
    background-color:#0F0;
}
.blueText {
    background-color:#00F;
}

You could use option { background-color: #FFF; } if you want the list to be white.

HTML

<select id="mySelect" class="greenText">
    <option class="greenText" value="apple" >Apple</option>
    <option class="redText"   value="banana" >Banana</option>
    <option class="blueText" value="grape" >Grape</option>
</select>

Since this is a select it doesn't really make sense to use .yellowText as none selected if that's what you were getting at as something must be selected.

405 method not allowed Web API

Make sure your controller inherits from Controller class.

It might even be crazier that stuff would work locally even without that.

C#, Looping through dataset and show each record from a dataset column

DateTime TaskStart = DateTime.Parse(dr["TaskStart"].ToString());

How to convert a string to number in TypeScript?

There are three ways

 let a = + '12'; 
 let b = parseInt('12' , 10); // 10 means decimal number
 let c = Number('12');

Change string color with NSAttributedString?

You can create NSAttributedString

NSDictionary *attributes = @{ NSForegroundColorAttributeName : [UIColor redColor] };
NSAttributedString *attrStr = [[NSAttributedString alloc] initWithString:@"My Color String" attributes:attrs];

OR NSMutableAttributedString to apply custom attributes with Ranges.

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:[NSString stringWithFormat:@"%@%@", methodPrefix, method] attributes: @{ NSFontAttributeName : FONT_MYRIADPRO(48) }];
[attributedString addAttribute:NSFontAttributeName value:FONT_MYRIADPRO_SEMIBOLD(48) range:NSMakeRange(methodPrefix.length, method.length)];

Available Attributes: NSAttributedStringKey


UPDATE:

Swift 5.1

let message: String = greeting + someMessage
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = 2.0
    
// Note: UIFont(appFontFamily:ofSize:) is extended init.
let regularAttributes: [NSAttributedString.Key : Any] = [.font : UIFont(appFontFamily: .regular, ofSize: 15)!, .paragraphStyle : paragraphStyle]
let boldAttributes = [NSAttributedString.Key.font : UIFont(appFontFamily: .semiBold, ofSize: 15)!]

let mutableString = NSMutableAttributedString(string: message, attributes: regularAttributes)
mutableString.addAttributes(boldAttributes, range: NSMakeRange(0, greeting.count))

how to download file using AngularJS and calling MVC API?

using FileSaver.js solved my issue thanks for help, below code helped me

'$'

 DownloadClaimForm: function (claim) 
{
 url = baseAddress + "DownLoadFile";
 return  $http.post(baseAddress + "DownLoadFile", claim, {responseType: 'arraybuffer' })
                            .success(function (data) {
                                var file = new Blob([data], { type: 'application/pdf' });
                                saveAs(file, 'Claims.pdf');
                            });


    }

VBA for filtering columns

Here's a different approach. The heart of it was created by turning on the Macro Recorder and filtering the columns per your specifications. Then there's a bit of code to copy the results. It will run faster than looping through each row and column:

Sub FilterAndCopy()
Dim LastRow As Long

Sheets("Sheet2").UsedRange.Offset(0).ClearContents
With Worksheets("Sheet1")
    .Range("$A:$E").AutoFilter
    .Range("$A:$E").AutoFilter field:=1, Criteria1:="#N/A"
    .Range("$A:$E").AutoFilter field:=2, Criteria1:="=String1", Operator:=xlOr, Criteria2:="=string2"
    .Range("$A:$E").AutoFilter field:=3, Criteria1:=">0"
    .Range("$A:$E").AutoFilter field:=5, Criteria1:="Number"
    LastRow = .Range("A" & .Rows.Count).End(xlUp).Row
    .Range("A1:A" & LastRow).SpecialCells(xlCellTypeVisible).EntireRow.Copy _
            Destination:=Sheets("Sheet2").Range("A1")
End With
End Sub

As a side note, your code has more loops and counter variables than necessary. You wouldn't need to loop through the columns, just through the rows. You'd then check the various cells of interest in that row, much like you did.

Non-static method requires a target

All the answers are pointing to a Lambda expression with an NRE (Null Reference Exception). I have found that it also occurs when using Linq to Entities. I thought it would be helpful to point out that this exception is not limited to just an NRE inside a Lambda expression.

How to block until an event is fired in c#

You can use ManualResetEvent. Reset the event before you fire secondary thread and then use the WaitOne() method to block the current thread. You can then have secondary thread set the ManualResetEvent which would cause the main thread to continue. Something like this:

ManualResetEvent oSignalEvent = new ManualResetEvent(false);

void SecondThread(){
    //DoStuff
    oSignalEvent.Set();
}

void Main(){
    //DoStuff
    //Call second thread
    System.Threading.Thread oSecondThread = new System.Threading.Thread(SecondThread);
    oSecondThread.Start();

    oSignalEvent.WaitOne(); //This thread will block here until the reset event is sent.
    oSignalEvent.Reset();
    //Do more stuff
}

get index of DataTable column with name

You can simply use DataColumnCollection.IndexOf

So that you can get the index of the required column by name then use it with your row:

row[dt.Columns.IndexOf("ColumnName")] = columnValue;

Receiving JSON data back from HTTP request

Building on @Panagiotis Kanavos' answer, here's a working method as example which will also return the response as an object instead of a string:

using System.Text;
using System.Net.Http;
using System.Threading.Tasks;
using Newtonsoft.Json; // Nuget Package

public static async Task<object> PostCallAPI(string url, object jsonObject)
{
    try
    {
        using (HttpClient client = new HttpClient())
        {
            var content = new StringContent(jsonObject.ToString(), Encoding.UTF8, "application/json");
            var response = await client.PostAsync(url, content);
            if (response != null)
            {
                var jsonString = await response.Content.ReadAsStringAsync();
                return JsonConvert.DeserializeObject<object>(jsonString);
            }
        }
    }
    catch (Exception ex)
    {
        myCustomLogger.LogException(ex);
    }
    return null;
}

Keep in mind that this is only an example and that you'd probably would like to use HttpClient as a shared instance instead of using it in a using-clause.

Are the days of passing const std::string & as a parameter over?

See “Herb Sutter "Back to the Basics! Essentials of Modern C++ Style”. Among other topics, he reviews the parameter passing advice that’s been given in the past, and new ideas that come in with C++11 and specifically looks at the idea of passing strings by value.

slide 24

The benchmarks show that passing std::strings by value, in cases where the function will copy it in anyway, can be significantly slower!

This is because you are forcing it to always make a full copy (and then move into place), while the const& version will update the old string which may reuse the already-allocated buffer.

See his slide 27: For “set” functions, option 1 is the same as it always was. Option 2 adds an overload for rvalue reference, but this gives a combinatorial explosion if there are multiple parameters.

It is only for “sink” parameters where a string must be created (not have its existing value changed) that the pass-by-value trick is valid. That is, constructors in which the parameter directly initializes the member of the matching type.

If you want to see how deep you can go in worrying about this, watch Nicolai Josuttis’s presentation and good luck with that (“Perfect — Done!” n times after finding fault with the previous version. Ever been there?)


This is also summarized as ?F.15 in the Standard Guidelines.

Returning binary file from controller in ASP.NET Web API

For Web API 2, you can implement IHttpActionResult. Here's mine:

using System;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading;
using System.Threading.Tasks;
using System.Web;
using System.Web.Http;

class FileResult : IHttpActionResult
{
    private readonly string _filePath;
    private readonly string _contentType;

    public FileResult(string filePath, string contentType = null)
    {
        if (filePath == null) throw new ArgumentNullException("filePath");

        _filePath = filePath;
        _contentType = contentType;
    }

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        var response = new HttpResponseMessage(HttpStatusCode.OK)
        {
            Content = new StreamContent(File.OpenRead(_filePath))
        };

        var contentType = _contentType ?? MimeMapping.GetMimeMapping(Path.GetExtension(_filePath));
        response.Content.Headers.ContentType = new MediaTypeHeaderValue(contentType);

        return Task.FromResult(response);
    }
}

Then something like this in your controller:

[Route("Images/{*imagePath}")]
public IHttpActionResult GetImage(string imagePath)
{
    var serverPath = Path.Combine(_rootPath, imagePath);
    var fileInfo = new FileInfo(serverPath);

    return !fileInfo.Exists
        ? (IHttpActionResult) NotFound()
        : new FileResult(fileInfo.FullName);
}

And here's one way you can tell IIS to ignore requests with an extension so that the request will make it to the controller:

<!-- web.config -->
<system.webServer>
  <modules runAllManagedModulesForAllRequests="true"/>

Calculating how many minutes there are between two times

In your quesion code you are using TimeSpan.FromMinutes incorrectly. Please see the MSDN Documentation for TimeSpan.FromMinutes, which gives the following method signature:

public static TimeSpan FromMinutes(double value)

hence, the following code won't compile

var intMinutes = TimeSpan.FromMinutes(varTime); // won't compile

Instead, you can use the TimeSpan.TotalMinutes property to perform this arithmetic. For instance:

TimeSpan varTime = (DateTime)varFinish - (DateTime)varValue; 
double fractionalMinutes = varTime.TotalMinutes;
int wholeMinutes = (int)fractionalMinutes;

Increasing heap space in Eclipse: (java.lang.OutOfMemoryError)

Sometimes the exception will not stop after you increase the memory in eclipse ini file. then try below option

Go to Window >> Preferences >> MyEclipse >> Java Enterprise Project >> Web Project >> Deployment Tab Under -> Under Library Deployment Policies UnCheck -> Jars from User Libraries

error: invalid initialization of non-const reference of type ‘int&’ from an rvalue of type ‘int’

12 is a compile-time constant which can not be changed unlike the data referenced by int&. What you can do is

const int& z = 12;

How to get std::vector pointer to the raw data?

something.data() will return a pointer to the data space of the vector.

Binding Combobox Using Dictionary as the Datasource

Use -->

comboBox1.DataSource = colors.ToList();

Unless the dictionary is converted to list, combo-box can't recognize its members.

How could I convert data from string to long in c#

This answer no longer works, and I cannot come up with anything better then the other answers (see below) listed here. Please review and up-vote them.

Convert.ToInt64("1100.25")

Method signature from MSDN:

public static long ToInt64(
    string value
)

POSTing JsonObject With HttpClient From Web API

The easiest way is to use a StringContent, with the JSON representation of your JSON object.

httpClient.Post(
    "",
    new StringContent(
        myObject.ToString(),
        Encoding.UTF8,
        "application/json"));

Object cannot be cast from DBNull to other types

TryParse is usually the most elegant way to handle this type of thing:

long temp = 0;
if (Int64.TryParse(dataAccCom.GetParameterValue(IDbCmd, "op_Id").ToString(), out temp))
{
   DataTO.Id = temp;
}     

There is already an open DataReader associated with this Command which must be closed first

I solved this problem by changing await _accountSessionDataModel.SaveChangesAsync(); to _accountSessionDataModel.SaveChanges(); in my Repository class.

 public async Task<Session> CreateSession()
    {
        var session = new Session();

        _accountSessionDataModel.Sessions.Add(session);
        await _accountSessionDataModel.SaveChangesAsync();
     }

Changed it to:

 public Session CreateSession()
    {
        var session = new Session();

        _accountSessionDataModel.Sessions.Add(session);
        _accountSessionDataModel.SaveChanges();
     }

The problem was that I updated the Sessions in the frontend after creating a session (in code), but because SaveChangesAsync happens asynchronously, fetching the sessions caused this error because apparently the SaveChangesAsync operation was not yet ready.

how to convert object to string in java

You can create toString() method to convert object to string.

int bid;
String bname;
double bprice;

Book(String str)
{
    String[] s1 = str.split("-");
    bid = Integer.parseInt(s1[0]);
    bname = s1[1];
    bprice = Double.parseDouble(s1[2]);
}

public String toString()
{
    return bid+"-"+bname+"-"+bprice;
}   

public static void main(String[] s)
{
    Book b1 = new Book("12-JAVA-200.50");
    System.out.println(b1);
}

Returning a file to View/Download in ASP.NET MVC

If, like me, you've come to this topic via Razor components as you're learning Blazor, then you'll find you need to think a little more outside of the box to solve this problem. It's a bit of a minefield if (also like me) Blazor is your first forray into the MVC-type world, as the documentation isn't as helpful for such 'menial' tasks.

So, at the time of writing, you cannot achieve this using vanilla Blazor/Razor without embedding an MVC controller to handle the file download part an example of which is as below:

using Microsoft.AspNetCore.Mvc;
using Microsoft.Net.Http.Headers;

[Route("api/[controller]")]
[ApiController]
public class FileHandlingController : ControllerBase
{
    [HttpGet]
    public FileContentResult Download(int attachmentId)
    {
        TaskAttachment taskFile = null;

        if (attachmentId > 0)
        {
            // taskFile = <your code to get the file>
            // which assumes it's an object with relevant properties as required below

            if (taskFile != null)
            {
                var cd = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment")
                {
                    FileNameStar = taskFile.Filename
                };

                Response.Headers.Add(HeaderNames.ContentDisposition, cd.ToString());
            }
        }

        return new FileContentResult(taskFile?.FileData, taskFile?.FileContentType);
    }
}

Next, make sure your application startup (Startup.cs) is configured to correctly use MVC and has the following line present (add it if not):

        services.AddMvc();

.. and then finally modify your component to link to the controller, for example (iterative based example using a custom class):

    <tbody>
        @foreach (var attachment in yourAttachments)
        {
        <tr>
            <td><a href="api/[email protected]" target="_blank">@attachment.Filename</a> </td>
            <td>@attachment.CreatedUser</td>
            <td>@attachment.Created?.ToString("dd MMM yyyy")</td>
            <td><ul><li class="oi oi-circle-x delete-attachment"></li></ul></td>
        </tr>
        }
        </tbody>

Hopefully this helps anyone who struggled (like me!) to get an appropriate answer to this seemingly simple question in the realms of Blazor…!

Java List.add() UnsupportedOperationException

You must initialize your List seeAlso :

List<String> seeAlso = new Vector<String>();

or

List<String> seeAlso = new ArrayList<String>();

An item with the same key has already been added

I found the answer.It was because of the variables. Like int a and string a. there were two variables with the same name.

C++11 rvalues and move semantics confusion (return statement)

The simple answer is you should write code for rvalue references like you would regular references code, and you should treat them the same mentally 99% of the time. This includes all the old rules about returning references (i.e. never return a reference to a local variable).

Unless you are writing a template container class that needs to take advantage of std::forward and be able to write a generic function that takes either lvalue or rvalue references, this is more or less true.

One of the big advantages to the move constructor and move assignment is that if you define them, the compiler can use them in cases were the RVO (return value optimization) and NRVO (named return value optimization) fail to be invoked. This is pretty huge for returning expensive objects like containers & strings by value efficiently from methods.

Now where things get interesting with rvalue references, is that you can also use them as arguments to normal functions. This allows you to write containers that have overloads for both const reference (const foo& other) and rvalue reference (foo&& other). Even if the argument is too unwieldy to pass with a mere constructor call it can still be done:

std::vector vec;
for(int x=0; x<10; ++x)
{
    // automatically uses rvalue reference constructor if available
    // because MyCheapType is an unamed temporary variable
    vec.push_back(MyCheapType(0.f));
}


std::vector vec;
for(int x=0; x<10; ++x)
{
    MyExpensiveType temp(1.0, 3.0);
    temp.initSomeOtherFields(malloc(5000));

    // old way, passed via const reference, expensive copy
    vec.push_back(temp);

    // new way, passed via rvalue reference, cheap move
    // just don't use temp again,  not difficult in a loop like this though . . .
    vec.push_back(std::move(temp));
}

The STL containers have been updated to have move overloads for nearly anything (hash key and values, vector insertion, etc), and is where you will see them the most.

You can also use them to normal functions, and if you only provide an rvalue reference argument you can force the caller to create the object and let the function do the move. This is more of an example than a really good use, but in my rendering library, I have assigned a string to all the loaded resources, so that it is easier to see what each object represents in the debugger. The interface is something like this:

TextureHandle CreateTexture(int width, int height, ETextureFormat fmt, string&& friendlyName)
{
    std::unique_ptr<TextureObject> tex = D3DCreateTexture(width, height, fmt);
    tex->friendlyName = std::move(friendlyName);
    return tex;
}

It is a form of a 'leaky abstraction' but allows me to take advantage of the fact I had to create the string already most of the time, and avoid making yet another copying of it. This isn't exactly high-performance code but is a good example of the possibilities as people get the hang of this feature. This code actually requires that the variable either be a temporary to the call, or std::move invoked:

// move from temporary
TextureHandle htex = CreateTexture(128, 128, A8R8G8B8, string("Checkerboard"));

or

// explicit move (not going to use the variable 'str' after the create call)
string str("Checkerboard");
TextureHandle htex = CreateTexture(128, 128, A8R8G8B8, std::move(str));

or

// explicitly make a copy and pass the temporary of the copy down
// since we need to use str again for some reason
string str("Checkerboard");
TextureHandle htex = CreateTexture(128, 128, A8R8G8B8, string(str));

but this won't compile!

string str("Checkerboard");
TextureHandle htex = CreateTexture(128, 128, A8R8G8B8, str);

Binding a list in @RequestParam

Subscribing what basil said in a comment to the question itself, if method = RequestMethod.GET you can use @RequestParam List<String> groupVal.

Then calling the service with the list of params is as simple as:

API_URL?groupVal=kkk,ccc,mmm

How to check if all list items have the same value and return it, or return an “otherValue” if they don’t?

var val = yyy.First().Value;
return yyy.All(x=>x.Value == val) ? val : otherValue; 

Cleanest way I can think of. You can make it a one-liner by inlining val, but First() would be evaluated n times, doubling execution time.

To incorporate the "empty set" behavior specified in the comments, you simply add one more line before the two above:

if(yyy == null || !yyy.Any()) return otherValue;

push_back vs emplace_back

emplace_back conforming implementation will forward arguments to the vector<Object>::value_typeconstructor when added to the vector. I recall Visual Studio didn't support variadic templates, but with variadic templates will be supported in Visual Studio 2013 RC, so I guess a conforming signature will be added.

With emplace_back, if you forward the arguments directly to vector<Object>::value_type constructor, you don't need a type to be movable or copyable for emplace_back function, strictly speaking. In the vector<NonCopyableNonMovableObject> case, this is not useful, since vector<Object>::value_type needs a copyable or movable type to grow.

But note that this could be useful for std::map<Key, NonCopyableNonMovableObject>, since once you allocate an entry in the map, it doesn't need to be moved or copied ever anymore, unlike with vector, meaning that you can use std::map effectively with a mapped type that is neither copyable nor movable.

Example: Communication between Activity and Service using Messaging

Note: You don't need to check if your service is running, CheckIfServiceIsRunning(), because bindService() will start it if it isn't running.

Also: if you rotate the phone you don't want it to bindService() again, because onCreate() will be called again. Be sure to define onConfigurationChanged() to prevent this.

Dynamically Add Variable Name Value Pairs to JSON Object

From what the other answers have proposed, I believe this might help:

var object = ips[ipId];
var name = "Joe";
var anothername = "Fred";
var value = "Thingy";
var anothervalue = "Fingy";
object[name] = value;
object[anothername] = anothervalue;

However, this is not tested, just an assumption based on the constant repetition of:

object["string"] = value;
//object = {string: value}

Animate visibility modes, GONE and VISIBLE

Visibility change itself can be easy animated by overriding setVisibility method. Look at complete code:

public class SimpleViewAnimator extends FrameLayout
{
    private Animation inAnimation;
    private Animation outAnimation;

    public SimpleViewAnimator(Context context)
    {
        super(context);
    }

    public void setInAnimation(Animation inAnimation)
    {
        this.inAnimation = inAnimation;
    }

    public void setOutAnimation(Animation outAnimation)
    {
        this.outAnimation = outAnimation;
    }

    @Override
    public void setVisibility(int visibility)
    {
        if (getVisibility() != visibility)
        {
            if (visibility == VISIBLE)
            {
                if (inAnimation != null) startAnimation(inAnimation);
            }
            else if ((visibility == INVISIBLE) || (visibility == GONE))
            {
                if (outAnimation != null) startAnimation(outAnimation);
            }
        }

        super.setVisibility(visibility);
    }
}

REST API Best practices: Where to put parameters?

"Pack" and POST your data against the "context" that universe-resource-locator provides, which means #1 for the sake of the locator.

Mind the limitations with #2. I prefer POSTs to #1.

note: limitations are discussed for

POST in Is there a max size for POST parameter content?

GET in Is there a limit to the length of a GET request? and Max size of URL parameters in _GET

p.s. these limits are based on the client capabilities (browser) and server(configuration).

An error occurred while executing the command definition. See the inner exception for details

In my case, I messed up the connectionString property in a publish profile, trying to access the wrong database (Initial Catalog). Entity Framework then complains that the entities do not match the database, and rightly so.

Java getting the Enum name given the Enum Value

Try below code

public enum SalaryHeadMasterEnum {

    BASIC_PAY("basic pay"),
    MEDICAL_ALLOWANCE("Medical Allowance");

    private String name;

    private SalaryHeadMasterEnum(String stringVal) {
        name=stringVal;
    }
    public String toString(){
        return name;
    }

    public static String getEnumByString(String code){
        for(SalaryHeadMasterEnum e : SalaryHeadMasterEnum.values()){
            if(e.name.equals(code)) return e.name();
        }
        return null;
    }
}

Now you can use below code to retrieve the Enum by Value

SalaryHeadMasterEnum.getEnumByString("Basic Pay")

Use Below code to get ENUM as String

SalaryHeadMasterEnum.BASIC_PAY.name()

Use below code to get string Value for enum

SalaryHeadMasterEnum.BASIC_PAY.toString()

What are rvalues, lvalues, xvalues, glvalues, and prvalues?

Why are these new categories needed? Are the WG21 gods just trying to confuse us mere mortals?

I don't feel that the other answers (good though many of them are) really capture the answer to this particular question. Yes, these categories and such exist to allow move semantics, but the complexity exists for one reason. This is the one inviolate rule of moving stuff in C++11:

Thou shalt move only when it is unquestionably safe to do so.

That is why these categories exist: to be able to talk about values where it is safe to move from them, and to talk about values where it is not.

In the earliest version of r-value references, movement happened easily. Too easily. Easily enough that there was a lot of potential for implicitly moving things when the user didn't really mean to.

Here are the circumstances under which it is safe to move something:

  1. When it's a temporary or subobject thereof. (prvalue)
  2. When the user has explicitly said to move it.

If you do this:

SomeType &&Func() { ... }

SomeType &&val = Func();
SomeType otherVal{val};

What does this do? In older versions of the spec, before the 5 values came in, this would provoke a move. Of course it does. You passed an rvalue reference to the constructor, and thus it binds to the constructor that takes an rvalue reference. That's obvious.

There's just one problem with this; you didn't ask to move it. Oh, you might say that the && should have been a clue, but that doesn't change the fact that it broke the rule. val isn't a temporary because temporaries don't have names. You may have extended the lifetime of the temporary, but that means it isn't temporary; it's just like any other stack variable.

If it's not a temporary, and you didn't ask to move it, then moving is wrong.

The obvious solution is to make val an lvalue. This means that you can't move from it. OK, fine; it's named, so its an lvalue.

Once you do that, you can no longer say that SomeType&& means the same thing everwhere. You've now made a distinction between named rvalue references and unnamed rvalue references. Well, named rvalue references are lvalues; that was our solution above. So what do we call unnamed rvalue references (the return value from Func above)?

It's not an lvalue, because you can't move from an lvalue. And we need to be able to move by returning a &&; how else could you explicitly say to move something? That is what std::move returns, after all. It's not an rvalue (old-style), because it can be on the left side of an equation (things are actually a bit more complicated, see this question and the comments below). It is neither an lvalue nor an rvalue; it's a new kind of thing.

What we have is a value that you can treat as an lvalue, except that it is implicitly moveable from. We call it an xvalue.

Note that xvalues are what makes us gain the other two categories of values:

  • A prvalue is really just the new name for the previous type of rvalue, i.e. they're the rvalues that aren't xvalues.

  • Glvalues are the union of xvalues and lvalues in one group, because they do share a lot of properties in common.

So really, it all comes down to xvalues and the need to restrict movement to exactly and only certain places. Those places are defined by the rvalue category; prvalues are the implicit moves, and xvalues are the explicit moves (std::move returns an xvalue).

Convert NSNumber to int in Objective-C

Have a look at the documentation. Use the intValue method:

NSNumber *number = [dict objectForKey:@"integer"];
int intValue = [number intValue];

How to read embedded resource text file

This is a class which you might find very convenient for reading embedded resource files from the current Assembly:

using System.IO;
using System.Linq;
using System.Text;

public static class EmbeddedResourceUtils
{
    public static string ReadFromResourceFile(string endingFileName)
    {
        var assembly = Assembly.GetExecutingAssembly();
        var manifestResourceNames = assembly.GetManifestResourceNames();

        foreach (var resourceName in manifestResourceNames)
        {
            var fileNameFromResourceName = _GetFileNameFromResourceName(resourceName);
            if (!fileNameFromResourceName.EndsWith(endingFileName))
            {
                continue;
            }

            using (var manifestResourceStream = assembly.GetManifestResourceStream(resourceName))
            {
                if (manifestResourceStream == null)
                {
                    continue;
                }

                using (var streamReader = new StreamReader(manifestResourceStream))
                {
                    return streamReader.ReadToEnd();
                }
            }
        }

        return null;
    }
    
    // https://stackoverflow.com/a/32176198/3764804
    private static string _GetFileNameFromResourceName(string resourceName)
    {
        var stringBuilder = new StringBuilder();
        var escapeDot = false;
        var haveExtension = false;

        for (var resourceNameIndex = resourceName.Length - 1;
            resourceNameIndex >= 0;
            resourceNameIndex--)
        {
            if (resourceName[resourceNameIndex] == '_')
            {
                escapeDot = true;
                continue;
            }

            if (resourceName[resourceNameIndex] == '.')
            {
                if (!escapeDot)
                {
                    if (haveExtension)
                    {
                        stringBuilder.Append('\\');
                        continue;
                    }

                    haveExtension = true;
                }
            }
            else
            {
                escapeDot = false;
            }

            stringBuilder.Append(resourceName[resourceNameIndex]);
        }

        var fileName = Path.GetDirectoryName(stringBuilder.ToString());
        return fileName == null ? null : new string(fileName.Reverse().ToArray());
    }
}

When using .net MVC RadioButtonFor(), how do you group so only one selection can be made?

In my case, I had a collection of radio buttons that needed to be in a group. I just included a 'Selected' property in the model. Then, in the loop to output the radiobuttons just do...

@Html.RadioButtonFor(m => Model.Selected, Model.Categories[i].Title)

This way, the name is the same for all radio buttons. When the form is posted, the 'Selected' property is equal to the category title (or id or whatever) and this can be used to update the binding on the relevant radiobutton, like this...

model.Categories.Find(m => m.Title.Equals(model.Selected)).Selected = true;

May not be the best way, but it does work.

SELECT INTO Variable in MySQL DECLARE causes syntax error?

I ran into this same issue, but I think I know what's causing the confusion. If you use MySql Query Analyzer, you can do this just fine:

SELECT myvalue 
INTO @myvar 
FROM mytable 
WHERE anothervalue = 1;

However, if you put that same query in MySql Workbench, it will throw a syntax error. I don't know why they would be different, but they are. To work around the problem in MySql Workbench, you can rewrite the query like this:

SELECT @myvar:=myvalue
FROM mytable
WHERE anothervalue = 1;

No connection could be made because the target machine actively refused it?

This is really specific, but if you receive this error after trying to connect to a database using mongo, what worked for me was running mongod.exe before running mongo.exe and then the connection worked fine. Hope this helps someone.

Passing parameters to JavaScript files

You can pass parameters with arbitrary attributes. This works in all recent browsers.

<script type="text/javascript" data-my_var_1="some_val_1" data-my_var_2="some_val_2" src="/js/somefile.js"></script>

Inside somefile.js you can get passed variables values this way:

........

var this_js_script = $('script[src*=somefile]'); // or better regexp to get the file name..

var my_var_1 = this_js_script.attr('data-my_var_1');   
if (typeof my_var_1 === "undefined" ) {
   var my_var_1 = 'some_default_value';
}
alert(my_var_1); // to view the variable value

var my_var_2 = this_js_script.attr('data-my_var_2');   
if (typeof my_var_2 === "undefined" ) {
   var my_var_2 = 'some_default_value';
}
alert(my_var_2); // to view the variable value

...etc...

Parsing query strings on Android

This works for me.. I'm not sure why every one was after a Map, List> All I needed was a simple name value Map.

To keep things simple I used the build in URI.getQuery();

public static Map<String, String> getUrlParameters(URI uri)
    throws UnsupportedEncodingException {
    Map<String, String> params = new HashMap<String, String>();
    for (String param : uri.getQuery().split("&")) {
        String pair[] = param.split("=");
        String key = URLDecoder.decode(pair[0], "UTF-8");
        String value = "";
        if (pair.length > 1) {
            value = URLDecoder.decode(pair[1], "UTF-8");
        }
        params.put(new String(key), new String(value));
    }
    return params;
}

LINQ: "contains" and a Lambda query

Use Any() instead of Contains():

buildingStatus.Any(item => item.GetCharValue() == v.Status)

How can I find the last element in a List<>?

To get the last item of a collection use LastOrDefault() and Last() extension methods

var lastItem = integerList.LastOrDefault();

OR

var lastItem = integerList.Last();

Remeber to add using System.Linq;, or this method won't be available.

Where's my JSON data in my incoming Django request?

The HTTP POST payload is just a flat bunch of bytes. Django (like most frameworks) decodes it into a dictionary from either URL encoded parameters, or MIME-multipart encoding. If you just dump the JSON data in the POST content, Django won't decode it. Either do the JSON decoding from the full POST content (not the dictionary); or put the JSON data into a MIME-multipart wrapper.

In short, show the JavaScript code. The problem seems to be there.

Determine whether an array contains a value

It's almost always safer to use a library like lodash simply because of all the issues with cross-browser compatibilities and efficiency.

Efficiency because you can be guaranteed that at any given time, a hugely popular library like underscore will have the most efficient method of accomplishing a utility function like this.

_.includes([1, 2, 3], 3); // returns true

If you're concerned about the bulk that's being added to your application by including the whole library, know that you can include functionality separately:

var includes = require('lodash/collections/includes');

NOTICE: With older versions of lodash, this was _.contains() rather than _.includes().

"The Controls collection cannot be modified because the control contains code blocks"

Tags <%= %> not works into a tag with runat="server". Move your code with <%= %> into runat="server" to an other tag (body, head, ...), or remove runat="server" from container.

How do I convert a float to an int in Objective C?

what's wrong with:

int myInt = myFloat;

bear in mind this'll use the default rounding rule, which is towards zero (i.e. -3.9f becomes -3)

Trigger to fire only if a condition is met in SQL Server

CREATE TRIGGER
    [dbo].[SystemParameterInsertUpdate]
ON 
    [dbo].[SystemParameter]
FOR INSERT, UPDATE 
AS
  BEGIN
    SET NOCOUNT ON 

    DECLARE @StartRow int
    DECLARE @EndRow int
    DECLARE @CurrentRow int

    SET @StartRow = 1
    SET @EndRow = (SELECT count(*) FROM inserted)
    SET @CurrentRow = @StartRow

    WHILE @CurrentRow <= @EndRow BEGIN

        IF (SELECT Attribute FROM (SELECT ROW_NUMBER() OVER (ORDER BY Attribute ASC) AS 'RowNum', Attribute FROM inserted) AS INS WHERE RowNum = @CurrentRow) LIKE 'NoHist_%' BEGIN

            INSERT INTO SystemParameterHistory(
                Attribute,
                ParameterValue,
                ParameterDescription,
                ChangeDate)
            SELECT
                I.Attribute,
                I.ParameterValue,
                I.ParameterDescription,
                I.ChangeDate
            FROM
                (SELECT Attribute, ParameterValue, ParameterDescription, ChangeDate FROM (
                                                                                            SELECT ROW_NUMBER() OVER (ORDER BY Attribute ASC) AS 'RowNum', * 
                                                                                            FROM inserted)
                                                                                    AS I 
            WHERE RowNum = @CurrentRow

        END --END IF

    SET @CurrentRow = @CurrentRow + 1

    END --END WHILE
END --END TRIGGER

Pass a PHP string to a JavaScript variable (and escape newlines)

function escapeJavaScriptText($string)
{
    return str_replace("\n", '\n', str_replace('"', '\"', addcslashes(str_replace("\r", '', (string)$string), "\0..\37'\\")));
}

How do you redirect to a page using the POST verb?

HTTP doesn't support redirection to a page using POST. When you redirect somewhere, the HTTP "Location" header tells the browser where to go, and the browser makes a GET request for that page. You'll probably have to just write the code for your page to accept GET requests as well as POST requests.

XML Serialize generic list of serializable objects

I have an solution for a generic List<> with dynamic binded items.

class PersonalList it's the root element

[XmlRoot("PersonenListe")]
[XmlInclude(typeof(Person))] // include type class Person
public class PersonalList
{
    [XmlArray("PersonenArray")]
    [XmlArrayItem("PersonObjekt")]
    public List<Person> Persons = new List<Person>();

    [XmlElement("Listname")]
    public string Listname { get; set; }

    // Konstruktoren 
    public PersonalList() { }

    public PersonalList(string name)
    {
        this.Listname = name;
    }

    public void AddPerson(Person person)
    {
        Persons.Add(person);
    }
}

class Person it's an single list element

[XmlType("Person")] // define Type
[XmlInclude(typeof(SpecialPerson)), XmlInclude(typeof(SuperPerson))]  
        // include type class SpecialPerson and class SuperPerson
public class Person
{
    [XmlAttribute("PersID", DataType = "string")]
    public string ID { get; set; }

    [XmlElement("Name")]
    public string Name { get; set; }

    [XmlElement("City")]
    public string City { get; set; }

    [XmlElement("Age")]
    public int Age { get; set; }

    // Konstruktoren 
    public Person() { }

    public Person(string name, string city, int age, string id)
    {
        this.Name = name;
        this.City = city;
        this.Age = age;
        this.ID = id;
    }
}

class SpecialPerson inherits Person

[XmlType("SpecialPerson")] // define Type
public class SpecialPerson : Person
{
    [XmlElement("SpecialInterests")]
    public string Interests { get; set; }

    public SpecialPerson() { }

    public SpecialPerson(string name, string city, int age, string id, string interests)
    {
        this.Name = name;
        this.City = city;
        this.Age = age;
        this.ID = id;
        this.Interests = interests;
    }
}

class SuperPerson inherits Person

[XmlType("SuperPerson")] // define Type
public class SuperPerson : Person
{
    [XmlArray("Skills")]
    [XmlArrayItem("Skill")]
    public List<String> Skills { get; set; }

    [XmlElement("Alias")]
    public string Alias { get; set; }

    public SuperPerson() 
    {
        Skills = new List<String>();
    }

    public SuperPerson(string name, string city, int age, string id, string[] skills, string alias)
    {
        Skills = new List<String>();

        this.Name = name;
        this.City = city;
        this.Age = age;
        this.ID = id;
        foreach (string item in skills)
        {
            this.Skills.Add(item);   
        }
        this.Alias = alias;
    }
}

and the main test Source

static void Main(string[] args)
{
    PersonalList personen = new PersonalList(); 
    personen.Listname = "Friends";

    // normal person
    Person normPerson = new Person();
    normPerson.ID = "0";
    normPerson.Name = "Max Man";
    normPerson.City = "Capitol City";
    normPerson.Age = 33;

    // special person
    SpecialPerson specPerson = new SpecialPerson();
    specPerson.ID = "1";
    specPerson.Name = "Albert Einstein";
    specPerson.City = "Ulm";
    specPerson.Age = 36;
    specPerson.Interests = "Physics";

    // super person
    SuperPerson supPerson = new SuperPerson();
    supPerson.ID = "2";
    supPerson.Name = "Superman";
    supPerson.Alias = "Clark Kent";
    supPerson.City = "Metropolis";
    supPerson.Age = int.MaxValue;
    supPerson.Skills.Add("fly");
    supPerson.Skills.Add("strong");

    // Add Persons
    personen.AddPerson(normPerson);
    personen.AddPerson(specPerson);
    personen.AddPerson(supPerson);

    // Serialize 
    Type[] personTypes = { typeof(Person), typeof(SpecialPerson), typeof(SuperPerson) };
    XmlSerializer serializer = new XmlSerializer(typeof(PersonalList), personTypes); 
    FileStream fs = new FileStream("Personenliste.xml", FileMode.Create); 
    serializer.Serialize(fs, personen); 
    fs.Close(); 
    personen = null;

    // Deserialize 
    fs = new FileStream("Personenliste.xml", FileMode.Open); 
    personen = (PersonalList)serializer.Deserialize(fs); 
    serializer.Serialize(Console.Out, personen);
    Console.ReadLine();
}

Important is the definition and includes of the diffrent types.

Select single item from a list

Use the FirstOrDefault selector.

var list = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

var firstEven = list.FirstOrDefault(n => n % 2 == 0);

if (firstEven == 0)
    Console.WriteLine("no even number");
else 
    Console.WriteLine("first even number is {0}", firstEven);

Just pass in a predicate to the First or FirstOrDefault method and it'll happily go round' the list and picks the first match for you.

If there isn't a match, FirstOrDefault will returns the default value of whatever datatype the list items is.

Hope this helps :-)

Difference between single and double quotes in Bash

If you're referring to what happens when you echo something, the single quotes will literally echo what you have between them, while the double quotes will evaluate variables between them and output the value of the variable.

For example, this

#!/bin/sh
MYVAR=sometext
echo "double quotes gives you $MYVAR"
echo 'single quotes gives you $MYVAR'

will give this:

double quotes gives you sometext
single quotes gives you $MYVAR

Getting one value from a tuple

For anyone in the future looking for an answer, I would like to give a much clearer answer to the question.

# for making a tuple
my_tuple = (89, 32)
my_tuple_with_more_values = (1, 2, 3, 4, 5, 6)

# to concatenate tuples
another_tuple = my_tuple + my_tuple_with_more_values
print(another_tuple)
# (89, 32, 1, 2, 3, 4, 5, 6)

# getting a value from a tuple is similar to a list
first_val = my_tuple[0]
second_val = my_tuple[1]

# if you have a function called my_tuple_fun that returns a tuple,
# you might want to do this
my_tuple_fun()[0]
my_tuple_fun()[1]

# or this
v1, v2 = my_tuple_fun()

Hope this clears things up further for those that need it.

Getting Lat/Lng from Google marker

try this

var latlng = new google.maps.LatLng(51.4975941, -0.0803232);
var map = new google.maps.Map(document.getElementById('map'), {
    center: latlng,
    zoom: 11,
    mapTypeId: google.maps.MapTypeId.ROADMAP
});
var marker = new google.maps.Marker({
    position: latlng,
    map: map,
    title: 'Set lat/lon values for this property',
    draggable: true
});

google.maps.event.addListener(marker, 'dragend', function (event) {
    document.getElementById("latbox").value = this.getPosition().lat();
    document.getElementById("lngbox").value = this.getPosition().lng();
});

Reading *.wav files in Python

if its just two files and the sample rate is significantly high, you could just interleave them.

from scipy.io import wavfile
rate1,dat1 = wavfile.read(File1)
rate2,dat2 = wavfile.read(File2)

if len(dat2) > len(dat1):#swap shortest
    temp = dat2
    dat2 = dat1
    dat1 = temp

output = dat1
for i in range(len(dat2)/2): output[i*2]=dat2[i*2]

wavfile.write(OUTPUT,rate,dat)

Giving height to table and row in Bootstrap

For the <tr>'s just set

tr {
   line-height: 25px;
   min-height: 25px;
   height: 25px;
}

It works with bootstrap also. For the 100% height, 100% must be 100% of something. Therefore, you must define a fixed height for one of the containers, or the body. I guess you want the entire page to be 100%, so (example) :

body {
    height: 700px;
}
.table100, .row, .container, .table-responsive, .table-bordered  {
    height: 100%;
}

A workaround not to set a static height is by forcing the height in code according to the viewport :

$('body').height(document.documentElement.clientHeight);

all the above in this fiddle -> http://jsfiddle.net/LZuJt/

Note : I do not care that you have 25% height on #description, and 100% height on table. Guess it is just an example. And notice that clientHeight is not right since the documentElement is an iframe, but you'll get the picture in your own projekt :)

What does LINQ return when the results are empty

var lst = new List<int>() { 1, 2, 3 };
var ans = lst.Where( i => i > 3 );

(ans == null).Dump();  // False
(ans.Count() == 0 ).Dump();  // True

(Dump is from LinqPad)

Exporting PDF with jspdf not rendering CSS

To remove black background only add background-color: white; to the style of

How do I activate a virtualenv inside PyCharm's terminal?

Update:

The preferences in Settings (Preferences) | Tools | Terminal are global.
If you use a venv for each project, remember to use current path variable and a default venv name:

"cmd.exe" /k ""%CD%\venv\Scripts\activate"" 

For Windows users: when using PyCharm with a virtual environment, you can use the /K parameter to cmd.exe to set the virtual environment automatically.

PyCharm 3 or 4: Settings, Terminal, Default shell and add /K <path-to-your-activate.bat>.

PyCharm 5: Settings, Tools, Terminal, and add /K <path-to-your-activate.bat> to Shell path.

PyCharm 2016.1 or 2016.2: Settings, Tools, Terminal, and add ""/K <path-to-your-activate.bat>"" to Shell path and add (mind the quotes). Also add quotes around cmd.exe, resulting in:

"cmd.exe" /k ""C:\mypath\my-venv\Scripts\activate.bat""

push_back vs emplace_back

Optimization for emplace_back can be demonstrated in next example.

For emplace_back constructor A (int x_arg) will be called. And for push_back A (int x_arg) is called first and move A (A &&rhs) is called afterwards.

Of course, the constructor has to be marked as explicit, but for current example is good to remove explicitness.

#include <iostream>
#include <vector>
class A
{
public:
  A (int x_arg) : x (x_arg) { std::cout << "A (x_arg)\n"; }
  A () { x = 0; std::cout << "A ()\n"; }
  A (const A &rhs) noexcept { x = rhs.x; std::cout << "A (A &)\n"; }
  A (A &&rhs) noexcept { x = rhs.x; std::cout << "A (A &&)\n"; }

private:
  int x;
};

int main ()
{
  {
    std::vector<A> a;
    std::cout << "call emplace_back:\n";
    a.emplace_back (0);
  }
  {
    std::vector<A> a;
    std::cout << "call push_back:\n";
    a.push_back (1);
  }
  return 0;
}

output:

call emplace_back:
A (x_arg)

call push_back:
A (x_arg)
A (A &&)

Disable Input fields in reactive form

The best solution is here:

https://netbasal.com/disabling-form-controls-when-working-with-reactive-forms-in-angular-549dd7b42110

Outline of solution (in case of broken link):

(1) Create a directive

import { NgControl } from '@angular/forms';

@Directive({selector: '[disableControl]'})
export class DisableControlDirective {

  @Input() set disableControl( condition : boolean ) {
    const action = condition ? 'disable' : 'enable';
    this.ngControl.control[action]();
  }

  constructor( private ngControl : NgControl ) {}
}

(2) Use it like so

<input [formControl]="formControl" [disableControl]="condition">

(3) Since disabled inputs do not show in form.value on submit you may need to use the following instead (if required):

onSubmit(form) {
  const formValue = form.getRawValue() // gets form.value including disabled controls
  console.log(formValue)
}

VBScript -- Using error handling

You can regroup your steps functions calls in a facade function :

sub facade()
    call step1()
    call step2()
    call step3()
    call step4()
    call step5()
end sub

Then, let your error handling be in an upper function that calls the facade :

sub main()
    On error resume next

    call facade()

    If Err.Number <> 0 Then
        ' MsgBox or whatever. You may want to display or log your error there
        msgbox Err.Description
        Err.Clear
    End If

    On Error Goto 0
end sub

Now, let's suppose step3() raises an error. Since facade() doesn't handle errors (there is no On error resume next in facade()), the error will be returned to main() and step4() and step5() won't be executed.

Your error handling is now refactored in 1 code block

Visual Studio 2013 Install Fails: Program Compatibility Mode is on (Windows 10)

In my case, I tried to run from a mounted ISO. exec name are okay. I fixed the problem by copying all ISO files to the hard disk.

Get the key corresponding to the minimum value within a dictionary

If you are not sure that you have not multiple minimum values, I would suggest:

d = {320:1, 321:0, 322:3, 323:0}
print ', '.join(str(key) for min_value in (min(d.values()),) for key in d if d[key]==min_value)

"""Output:
321, 323
"""

Bootstrap throws Uncaught Error: Bootstrap's JavaScript requires jQuery

If you are using require.js than need to add window.$ = window.jQuery = require('jquery') in app.js

OR you can make dependent file load after parent file loaded.. such as below concept

require.config({
    baseUrl: "scripts/appScript",
    paths: {
        'jquery':'jQuery/jquery.min',
        'bootstrap':'bootstrap/bootstrap.min' 
    },
   shim
    shim: {
        'bootstrap':['jquery'],
        },

    // kick start application
    deps: ['app']
});

Above code shown that bootstrap is dependent on Jquery so i have added in shim and make it dependent

Find length of 2D array Python

You can also use np.size(a,1), 1 here is the axis and this will give you the number of columns

Converting date between DD/MM/YYYY and YYYY-MM-DD?

Your example code is wrong. This works:

import datetime

datetime.datetime.strptime("21/12/2008", "%d/%m/%Y").strftime("%Y-%m-%d")

The call to strptime() parses the first argument according to the format specified in the second, so those two need to match. Then you can call strftime() to format the result into the desired final format.

Run reg command in cmd (bat file)?

If memory serves correct, the reg add command will NOT create the entire directory path if it does not exist. Meaning that if any of the parent registry keys do not exist then they must be created manually one by one. It is really annoying, I know! Example:

@echo off
reg add "HKCU\Software\Policies"
reg add "HKCU\Software\Policies\Microsoft"
reg add "HKCU\Software\Policies\Microsoft\Internet Explorer"
reg add "HKCU\Software\Policies\Microsoft\Internet Explorer\Control Panel"
reg add "HKCU\Software\Policies\Microsoft\Internet Explorer\Control Panel" /v HomePage /t REG_DWORD /d 1 /f
pause

Correct way to load a Nib for a UIView subclass

Well you could either initialize the xib using a view controller and use viewController.view. or do it the way you did it. Only making a UIView subclass as the controller for UIView is a bad idea.

If you don't have any outlets from your custom view then you can directly use a UIViewController class to initialize it.

Update: In your case:

UIViewController *genericViewCon = [[UIViewController alloc] initWithNibName:@"CustomView"];
//Assuming you have a reference for the activity indicator in your custom view class
CustomView *myView = (CustomView *)genericViewCon.view;
[parentView addSubview:myView];
//And when necessary
[myView.activityIndicator startAnimating]; //or stop

Otherwise you have to make a custom UIViewController(to make it as the file's owner so that the outlets are properly wired up).

YourCustomController *yCustCon = [[YourCustomController alloc] initWithNibName:@"YourXibName"].

Wherever you want to add the view you can use.

[parentView addSubview:yCustCon.view];

However passing the another view controller(already being used for another view) as the owner while loading the xib is not a good idea as the view property of the controller will be changed and when you want to access the original view, you won't have a reference to it.

EDIT: You will face this problem if you have setup your new xib with file's owner as the same main UIViewController class and tied the view property to the new xib view.

i.e;

  • YourMainViewController -- manages -- mainView
  • CustomView -- needs to load from xib as and when required.

The below code will cause confusion later on, if you write it inside view did load of YourMainViewController. That is because self.view from this point on will refer to your customview

-(void)viewDidLoad:(){
  UIView *childView= [[[NSBundle mainBundle] loadNibNamed:@"YourXibName" owner:self options:nil] objectAtIndex:0];
}

JavaScript replace \n with <br />

You need the /g for global matching

replace(/\n/g, "<br />");

This works for me for \n - see this answer if you might have \r\n

NOTE: The dupe is the most complete answer for any combination of \r\n, \r or \n

_x000D_
_x000D_
var messagetoSend = document.getElementById('x').value.replace(/\n/g, "<br />");_x000D_
console.log(messagetoSend);
_x000D_
<textarea id="x" rows="9">_x000D_
    Line 1_x000D_
    _x000D_
    _x000D_
    Line 2_x000D_
    _x000D_
    _x000D_
    _x000D_
    _x000D_
    Line 3_x000D_
</textarea>
_x000D_
_x000D_
_x000D_

UPDATE

It seems some visitors of this question have text with the breaklines escaped as

some text\r\nover more than one line"

In that case you need to escape the slashes:

replace(/\\r\\n/g, "<br />");

NOTE: All browsers will ignore \r in a string when rendering.

How do I find all files containing specific text on Linux?

You can use ack. It is like grep for source code. You can scan your entire file system with it.

Just do:

ack 'text-to-find-here'

In your root directory.

You can also use regular expressions, specify the filetype, etc.


UPDATE

I just discovered The Silver Searcher, which is like ack but 3-5x faster than it and even ignores patterns from a .gitignore file.

Making Enter key on an HTML form submit instead of activating button

$("form#submit input").on('keypress',function(event) {
  event.preventDefault();
  if (event.which === 13) {
    $('button.submit').trigger('click');
  }
});

Parsing CSV files in C#, with header

Let a library handle all the nitty-gritty details for you! :-)

Check out FileHelpers and stay DRY - Don't Repeat Yourself - no need to re-invent the wheel a gazillionth time....

You basically just need to define that shape of your data - the fields in your individual line in the CSV - by means of a public class (and so well-thought out attributes like default values, replacements for NULL values and so forth), point the FileHelpers engine at a file, and bingo - you get back all the entries from that file. One simple operation - great performance!

How to install PyQt5 on Windows?

To install the GPL version of PyQt5, run (see PyQt5 Project):

pip3 install pyqt5

This will install the Python wheel for your platform and your version of Python (assuming both are supported).

(The wheel will be automatically downloaded from the Python Package Index.)

The PyQt5 wheel includes the necessary parts of the LGPL version of Qt. There is no need to install Qt yourself.

(The required sip is packaged as a separate wheel and will be downloaded and installed automatically.)


Note:

If you get an error message saying something as

No downloads could be found that satisfy the requirement 

then you are probably using an unsupported version of Python.

JDBC ResultSet: I need a getDateTime, but there is only getDate and getTimeStamp

this worked:

    Date date = null;
    String dateStr = rs.getString("doc_date");
    if (dateStr != null) {
        date = dateFormat.parse(dateStr);
    }

using SimpleDateFormat.

.Net HttpWebRequest.GetResponse() raises exception when http status code 400 (bad request) is returned

I know this has already been answered a long time ago, but I made an extension method to hopefully help other people that come to this question.

Code:

public static class WebRequestExtensions
{
    public static WebResponse GetResponseWithoutException(this WebRequest request)
    {
        if (request == null)
        {
            throw new ArgumentNullException("request");
        }

        try
        {
            return request.GetResponse();
        }
        catch (WebException e)
        {
            if (e.Response == null)
            {
                throw;
            }

            return e.Response;
        }
    }
}

Usage:

var request = (HttpWebRequest)WebRequest.CreateHttp("http://invalidurl.com");

//... (initialize more fields)

using (var response = (HttpWebResponse)request.GetResponseWithoutException())
{
    Console.WriteLine("I got Http Status Code: {0}", response.StatusCode);
}

Converting LastLogon to DateTime format

Get-ADUser -Filter {Enabled -eq $true} -Properties Name,Manager,LastLogon | 
Select-Object Name,Manager,@{n='LastLogon';e={[DateTime]::FromFileTime($_.LastLogon)}}

Python string prints as [u'String']

Do you really mean u'String'?

In any event, can't you just do str(string) to get a string rather than a unicode-string? (This should be different for Python 3, for which all strings are unicode.)

Remove substring from the string

You can use the slice method:

a = "foobar"
a.slice! "foo"
=> "foo"
a
=> "bar"

there is a non '!' version as well. More info can be seen in the documentation about other versions as well: http://www.ruby-doc.org/core/classes/String.html#method-i-slice-21

Node JS Promise.all and forEach

Just to add to the solution presented, in my case I wanted to fetch multiple data from Firebase for a list of products. Here is how I did it:

useEffect(() => {
  const fn = p => firebase.firestore().doc(`products/${p.id}`).get();
  const actions = data.occasion.products.map(fn);
  const results = Promise.all(actions);
  results.then(data => {
    const newProducts = [];
    data.forEach(p => {
      newProducts.push({ id: p.id, ...p.data() });
    });
    setProducts(newProducts);
  });
}, [data]);

Removing object properties with Lodash

To select (or remove) object properties that satisfy a given condition deeply, you can use something like this:

function pickByDeep(object, condition, arraysToo=false) {
  return _.transform(object, (acc, val, key) => {
    if (_.isPlainObject(val) || arraysToo && _.isArray(val)) {
      acc[key] = pickByDeep(val, condition, arraysToo);
    } else if (condition(val, key, object)) {
      acc[key] = val;
    }
  });
}

https://codepen.io/aercolino/pen/MWgjyjm

What are the differences between json and simplejson Python modules?

json seems faster than simplejson in both cases of loads and dumps in latest version

Tested versions:

  • python: 3.6.8
  • json: 2.0.9
  • simplejson: 3.16.0

Results:

>>> def test(obj, call, data, times):
...   s = datetime.now()
...   print("calling: ", call, " in ", obj, " ", times, " times") 
...   for _ in range(times):
...     r = getattr(obj, call)(data)
...   e = datetime.now()
...   print("total time: ", str(e-s))
...   return r

>>> test(json, "dumps", data, 10000)
calling:  dumps  in  <module 'json' from 'C:\\Users\\jophine.antony\\AppData\\Local\\Programs\\Python\\Python36-32\\lib\\json\\__init__.py'>   10000  times
total time:  0:00:00.054857

>>> test(simplejson, "dumps", data, 10000)
calling:  dumps  in  <module 'simplejson' from 'C:\\Users\\jophine.antony\\AppData\\Local\\Programs\\Python\\Python36-32\\lib\\site-packages\\simplejson\\__init__.py'>   10000  times
total time:  0:00:00.419895
'{"1": 100, "2": "acs", "3.5": 3.5567, "d": [1, "23"], "e": {"a": "A"}}'

>>> test(json, "loads", strdata, 1000)
calling:  loads  in  <module 'json' from 'C:\\Users\\jophine.antony\\AppData\\Local\\Programs\\Python\\Python36-32\\lib\\json\\__init__.py'>   1000  times
total time:  0:00:00.004985
{'1': 100, '2': 'acs', '3.5': 3.5567, 'd': [1, '23'], 'e': {'a': 'A'}}

>>> test(simplejson, "loads", strdata, 1000)
calling:  loads  in  <module 'simplejson' from 'C:\\Users\\jophine.antony\\AppData\\Local\\Programs\\Python\\Python36-32\\lib\\site-packages\\simplejson\\__init__.py'>   1000  times
total time:  0:00:00.040890
{'1': 100, '2': 'acs', '3.5': 3.5567, 'd': [1, '23'], 'e': {'a': 'A'}}

For versions:

  • python: 3.7.4
  • json: 2.0.9
  • simplejson: 3.17.0

json was faster than simplejson during dumps operation but both maintained the same speed during loads operations

URL.Action() including route values

outgoing url in mvc generated based on the current routing schema.

because your Information action method require id parameter, and your route collection has id of your current requested url(/Admin/Information/5), id parameter automatically gotten from existing route collection values.

to solve this problem you should use UrlParameter.Optional:

 <a href="@Url.Action("Information", "Admin", new { id = UrlParameter.Optional })">Add an Admin</a>

Can you do greater than comparison on a date in a Rails 3 search?

Rails 6.1 added a new 'syntax' for comparison operators in where conditions, for example:

Post.where('id >': 9)
Post.where('id >=': 9)
Post.where('id <': 3)
Post.where('id <=': 3)

So your query can be rewritten as follows:

Note
  .where(user_id: current_user.id, notetype: p[:note_type], 'date >', p[:date])
  .order(date: :asc, created_at: :asc)

Here is a link to PR where you can find more examples.

matplotlib: Group boxplots

Just to add to the conversation, I have found a more elegant way to change the color of the box plot by iterating over the dictionary of the object itself

import numpy as np
import matplotlib.pyplot as plt

def color_box(bp, color):

    # Define the elements to color. You can also add medians, fliers and means
    elements = ['boxes','caps','whiskers']

    # Iterate over each of the elements changing the color
    for elem in elements:
        [plt.setp(bp[elem][idx], color=color) for idx in xrange(len(bp[elem]))]
    return

a = np.random.uniform(0,10,[100,5])    

bp = plt.boxplot(a)
color_box(bp, 'red')

Original box plot

Modified box plot

Cheers!

is it possible to evenly distribute buttons across the width of an android linearlayout

The easiest and fastest way, (but not the best), is to add a TextView with empty text attribute, like this

android:text=""

the background color must be the same at the LinearLayout, then you could use the padding property, like this

android:paddingBottom="250dp"

or whatever you need. Here is an example.

Help with packages in java - import does not work

It sounds like you are on the right track with your directory structure. When you compile the dependent code, specify the -classpath argument of javac. Use the parent directory of the com directory, where com, in turn, contains company/thing/YourClass.class

So, when you do this:

javac -classpath <parent> client.java

The <parent> should be referring to the parent of com. If you are in com, it would be ../.

How to find reason of failed Build without any error or warning

this can happen when one of the projects referenced is a higher version of the .NET framework than your current project.

gson throws MalformedJsonException

I suspect that result1 has some characters at the end of it that you can't see in the debugger that follow the closing } character. What's the length of result1 versus result2? I'll note that result2 as you've quoted it has 169 characters.

GSON throws that particular error when there's extra characters after the end of the object that aren't whitespace, and it defines whitespace very narrowly (as the JSON spec does) - only \t, \n, \r, and space count as whitespace. In particular, note that trailing NUL (\0) characters do not count as whitespace and will cause this error.

If you can't easily figure out what's causing the extra characters at the end and eliminate them, another option is to tell GSON to parse in lenient mode:

Gson gson = new Gson();
JsonReader reader = new JsonReader(new StringReader(result1));
reader.setLenient(true);
Userinfo userinfo1 = gson.fromJson(reader, Userinfo.class);

Error: org.testng.TestNGException: Cannot find class in classpath: EmpClass

For me the problem was very strange.
I have a testng.xml file at the root of my Eclipse project. When I changed the file through Eclipse, it wasn't changing the testng.xml file in my directory.

Turns out it made a copy of the folder into the eclipse workspace..

Hope this helps someone out

Git commit in terminal opens VIM, but can't get back to terminal

not really the answer to the VIM problem but you could use the command line to also enter the commit message:

git commit -m "This is the first commit"

How to search if dictionary value contains certain string with Python

Following is one liner for accepted answer ... (for one line lovers ..)

def search_dict(my_dict,searchFor):
    s_val = [[ k if searchFor in v else None for v in my_dict[k]] for k in my_dict]    
    return s_val

What's the difference between .bashrc, .bash_profile, and .environment?

I found information about .bashrc and .bash_profile here to sum it up:

.bash_profile is executed when you login. Stuff you put in there might be your PATH and other important environment variables.

.bashrc is used for non login shells. I'm not sure what that means. I know that RedHat executes it everytime you start another shell (su to this user or simply calling bash again) You might want to put aliases in there but again I am not sure what that means. I simply ignore it myself.

.profile is the equivalent of .bash_profile for the root. I think the name is changed to let other shells (csh, sh, tcsh) use it as well. (you don't need one as a user)

There is also .bash_logout wich executes at, yeah good guess...logout. You might want to stop deamons or even make a little housekeeping . You can also add "clear" there if you want to clear the screen when you log out.

Also there is a complete follow up on each of the configurations files here

These are probably even distro.-dependant, not all distros choose to have each configuraton with them and some have even more. But when they have the same name, they usualy include the same content.

What's the difference between align-content and align-items?

Well I have examined them on my browser.

align-content can change a line's height for row direction or width for column when it's value is stretch, or add empty space between or around the lines for space-between, space-around, flex-start, flex-end values.

align-items can change items height or position inside the line's area. When items are not wrapped they have only one line which it's area is always stretched to the flex-box area (even if the items overflow), and align-content has no effect on a single line. So it has no effect on items that are not wrapped and only align-items can change items position or stretch them when all of them are on a single line.

However, if they are wrapped you have multiple lines and items inside each line. And if all items of each line have the same height (for row direction) that line's height will be equal to those items height and you don't see any effect by changing align-items value.

So if you want to affect items by align-items when your items are wrapped and have the same height (for row direction) first you have to use align-content with stretch value in order to expand the lines area.

'if' statement in jinja2 template

Why the loop?

You could simply do this:

{% if 'priority' in data %}
    <p>Priority: {{ data['priority'] }}</p>
{% endif %}

When you were originally doing your string comparison, you should have used == instead.

No 'Access-Control-Allow-Origin' header is present on the requested resource—when trying to get data from a REST API

In my case,I use the below solution

Front-end or Angular

post(
    this.serverUrl, dataObjToPost,
    {
      headers: new HttpHeaders({
           'Content-Type':  'application/json',
         })
    }
)

back-end (I use php)

header("Access-Control-Allow-Origin: http://localhost:4200");
header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
header("Access-Control-Allow-Headers: Content-Type, Authorization");

$postdata = file_get_contents("php://input");
$request = json_decode($postdata);
print_r($request);

Check if specific input file is empty

    if (!$_FILES['image']['size'][0] == 0){ //}

How to preserve request url with nginx proxy_pass

In my scenario i have make this via below code in nginx vhost configuration

server {
server_name dashboards.etilize.com;

location / {
    proxy_pass http://demo.etilize.com/dashboards/;
    proxy_set_header Host $http_host;
}}

$http_host will set URL in Header same as requested

how to convert a string to an array in php

Take a look at the explode function.

<?php
// Example 1
$pizza  = "piece1 piece2 piece3 piece4 piece5 piece6";
$pieces = explode(" ", $pizza);
echo $pieces[0]; // piece1
echo $pieces[1]; // piece2
?>

Types in MySQL: BigInt(20) vs Int(20)

I wanted to add one more point is, if you are storing a really large number like 902054990011312 then one can easily see the difference of INT(20) and BIGINT(20). It is advisable to store in BIGINT.

adb uninstall failed

Open your application Manifest and check the application's package first.

After that, be sure that your device is set into debugger mode.

Check if ADB can interact with your device:

adb devices

If your device is listed, then run:

adb uninstall PACKAGE_WRITTEN_IN_MANIFEST

How do I erase an element from std::vector<> by index?

The erase method on std::vector is overloaded, so it's probably clearer to call

vec.erase(vec.begin() + index);

when you only want to erase a single element.

Calling multiple JavaScript functions on a button click

btnSAVE.Attributes.Add("OnClick", "var b = DropDownValidate('" + drp_compcode.ClientID + "') ;if (b) b=DropDownValidate('" + drp_divcode.ClientID + "');return b");

How can you change Network settings (IP Address, DNS, WINS, Host Name) with code in C#

Just made this in a few minutes:

using System;
using System.Management;

namespace WindowsFormsApplication_CS
{
  class NetworkManagement
  {
    public void setIP(string ip_address, string subnet_mask)
    {
      ManagementClass objMC =
        new ManagementClass("Win32_NetworkAdapterConfiguration");
      ManagementObjectCollection objMOC = objMC.GetInstances();

      foreach (ManagementObject objMO in objMOC)
      {
        if ((bool)objMO["IPEnabled"])
        {
          ManagementBaseObject setIP;
          ManagementBaseObject newIP =
            objMO.GetMethodParameters("EnableStatic");

          newIP["IPAddress"] = new string[] { ip_address };
          newIP["SubnetMask"] = new string[] { subnet_mask };

          setIP = objMO.InvokeMethod("EnableStatic", newIP, null);
        }
      }
    }

    public void setGateway(string gateway)
    {
      ManagementClass objMC = new ManagementClass("Win32_NetworkAdapterConfiguration");
      ManagementObjectCollection objMOC = objMC.GetInstances();

      foreach (ManagementObject objMO in objMOC)
      {
        if ((bool)objMO["IPEnabled"])
        {
          ManagementBaseObject setGateway;
          ManagementBaseObject newGateway =
            objMO.GetMethodParameters("SetGateways");

          newGateway["DefaultIPGateway"] = new string[] { gateway };
          newGateway["GatewayCostMetric"] = new int[] { 1 };

          setGateway = objMO.InvokeMethod("SetGateways", newGateway, null);
        }
      }
    }

    public void setDNS(string NIC, string DNS)
    {
      ManagementClass objMC = new ManagementClass("Win32_NetworkAdapterConfiguration");
      ManagementObjectCollection objMOC = objMC.GetInstances();

      foreach (ManagementObject objMO in objMOC)
      {
        if ((bool)objMO["IPEnabled"])
        {
          // if you are using the System.Net.NetworkInformation.NetworkInterface
          // you'll need to change this line to
          // if (objMO["Caption"].ToString().Contains(NIC))
          // and pass in the Description property instead of the name 
          if (objMO["Caption"].Equals(NIC))
          {
            ManagementBaseObject newDNS =
              objMO.GetMethodParameters("SetDNSServerSearchOrder");
            newDNS["DNSServerSearchOrder"] = DNS.Split(',');
            ManagementBaseObject setDNS =
              objMO.InvokeMethod("SetDNSServerSearchOrder", newDNS, null);
          }
        }
      }
    }

    public void setWINS(string NIC, string priWINS, string secWINS)
    {
      ManagementClass objMC = new ManagementClass("Win32_NetworkAdapterConfiguration");
      ManagementObjectCollection objMOC = objMC.GetInstances();

      foreach (ManagementObject objMO in objMOC)
      {
        if ((bool)objMO["IPEnabled"])
        {
          if (objMO["Caption"].Equals(NIC))
          {
            ManagementBaseObject setWINS;
            ManagementBaseObject wins =
            objMO.GetMethodParameters("SetWINSServer");
            wins.SetPropertyValue("WINSPrimaryServer", priWINS);
            wins.SetPropertyValue("WINSSecondaryServer", secWINS);

            setWINS = objMO.InvokeMethod("SetWINSServer", wins, null);
          }
        }
      }
    } 
  }
}

How to generate sample XML documents from their DTD or XSD?

Seems like nobody was able to answer the question so far :)

I use EclipseLink's MOXy to dynamically generate binding classes and then recursively go through the bound types. It is somewhat heavy, but it allows XPath value injection once the object tree is instantiated:

InputStream in = new FileInputStream(PATH_TO_XSD);
DynamicJAXBContext jaxbContext = 
            DynamicJAXBContextFactory.createContextFromXSD(in, null, Thread.currentThread().getContextClassLoader(), null);
DynamicType rootType = jaxbContext.getDynamicType(YOUR_ROOT_TYPE);
DynamicEntity root = rootType.newDynamicEntity();
traverseProps(jaxbContext, root, rootType, 0);

TraverseProps is pretty simple recursive method:

private void traverseProps(DynamicJAXBContext c, DynamicEntity e, DynamicType t, int level) throws DynamicException, InstantiationException, IllegalAccessException{
        if (t!=null) {
            logger.info(indent(level) + "type [" + t.getName() + "] of class [" + t.getClassName() + "] has " + t.getNumberOfProperties() + " props");
            for (String pName:t.getPropertiesNames()){
                Class<?> clazz = t.getPropertyType(pName);
                logger.info(indent(level) + "prop [" + pName + "] in type: " + clazz);
                //logger.info("prop [" + pName + "] in entity: " + e.get(pName));

                if (clazz==null){
                    // need to create an instance of object
                    String updatedClassName = pName.substring(0, 1).toUpperCase() + pName.substring(1);
                    logger.info(indent(level) + "Creating new type instance for " + pName + " using following class name: " + updatedClassName );
                    DynamicType child = c.getDynamicType("generated." + updatedClassName);
                    DynamicEntity childEntity = child.newDynamicEntity();
                    e.set(pName, childEntity);
                    traverseProps(c, childEntity, child, level+1);
                } else {
                    // just set empty value
                    e.set(pName, clazz.newInstance());
                }
            }
        } else {
            logger.warn("type is null");
        }
    }

Converting everything to XML is pretty easy:

Marshaller marshaller = jaxbContext.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(root, System.out);

An array of List in c#

use

List<int>[] a = new List<int>[100];

jQuery UI themes and HTML tables

Why noy just use the theme styles in the table? i.e.

<table>
  <thead class="ui-widget-header">
    <tr>
      <th>Id</th>
      <th>Description</th>
    </td>
  </thead>
  <tbody class="ui-widget-content">
    <tr>
      <td>...</td>
      <td>...</td>
    </tr>
      .
      .
      .
  </tbody>
</table>

And you don't need to use any code...

animating addClass/removeClass with jQuery

Another solution (but it requires jQueryUI as pointed out by Richard Neil Ilagan in comments) :-

addClass, removeClass and toggleClass also accepts a second argument; the time duration to go from one state to the other.

$(this).addClass('abc',1000);

See jsfiddle:- http://jsfiddle.net/6hvZT/1/

Where can I find Android's default icons?

you can use

android.R.drawable.xxx

(use autocomplete to see whats in there)

Or download the stuff from http://developer.android.com/design/downloads/index.html

Telegram Bot - how to get a group chat id?

My second Solution for the error {"ok":true,"result":[]}

  1. Go in your Telegram Group
  2. Add new User (Invite)
  3. Search for "getidsbot" => @getidsbot
  4. Message: /start@getidsbot
  5. Now you see the ID. looks like 1068773197, which is -1001068773197 for bots (with -100 prefix)!!!
  6. Kick the bot from the Group.
  7. Now go to the Webbrowser an send this line (Test Message):
https://api.telegram.org/botAPITOKENNUMBER:APITOKENKEYHERE/sendmessage?chat_id=-100GROUPNUMBER&text=test

Edit the API Token and the Group-ID!

How to write one new line in Bitbucket markdown?

It's possible, as addressed in Issue #7396:

When you do want to insert a <br /> break tag using Markdown, you end a line with two or more spaces, then type return or Enter.

How to locate the Path of the current project directory in Java (IDE)?

This is a code snippet to retrieve the path of the current running web application project in java.

public String getPath() throws UnsupportedEncodingException {

    String path = this.getClass().getClassLoader().getResource("").getPath();
    String fullPath = URLDecoder.decode(path, "UTF-8");
    String pathArr[] = fullPath.split("/WEB-INF/classes/");
    System.out.println(fullPath);
    System.out.println(pathArr[0]);
    fullPath = pathArr[0];

    return fullPath;

}

Source: https://dzone.com/articles/get-current-web-application

.prop('checked',false) or .removeAttr('checked')?

Another alternative to do the same thing is to filter on type=checkbox attribute:

$('input[type="checkbox"]').removeAttr('checked');

or

$('input[type="checkbox"]').prop('checked' , false);

Remeber that The difference between attributes and properties can be important in specific situations. Before jQuery 1.6, the .attr() method sometimes took property values into account when retrieving some attributes, which could cause inconsistent behavior. As of jQuery 1.6, the .prop() method provides a way to explicitly retrieve property values, while .attr() retrieves attributes.

Know more...

Share data between html pages

Well, you can actually send data via JavaScript - but you should know that this is the #1 exploit source in web pages as it's XSS :)

I personally would suggest to use an HTML formular instead and modify the javascript data on the server side.

But if you want to share between two pages (I assume they are not both on localhost, because that won't make sense to share between two both-backend-driven pages) you will need to specify the CORS headers to allow the browser to send data to the whitelisted domains.

These two links might help you, it shows the example via Node backend, but you get the point how it works:

Link 1

And, of course, the CORS spec:

Link 2

~Cheers

copy-item With Alternate Credentials

Since PowerShell doesn't support "-Credential" usage via many of the cmdlets (very annoying), and mapping a network drive via WMI proved to be very unreliable in PS, I found pre-caching the user credentials via a net use command to work quite well:

# cache credentials for our network path
net use \\server\C$ $password /USER:$username

Any operation that uses \\server\C$ in the path seems to work using the *-item cmdlets.

You can also delete the share when you're done:

net use \\server\C$ /delete

JavaFX open new window

If you just want a button to open up a new window, then something like this works:

btnOpenNewWindow.setOnAction(new EventHandler<ActionEvent>() {
    public void handle(ActionEvent event) {
        Parent root;
        try {
            root = FXMLLoader.load(getClass().getClassLoader().getResource("path/to/other/view.fxml"), resources);
            Stage stage = new Stage();
            stage.setTitle("My New Stage Title");
            stage.setScene(new Scene(root, 450, 450));
            stage.show();
            // Hide this current window (if this is what you want)
            ((Node)(event.getSource())).getScene().getWindow().hide();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }
}

How to type a new line character in SQL Server Management Studio

This is possible if you have an existing Newline character in the row or another row.

Select the square-box that represents the existing Newline character, copy it (control-C), and then paste it (control-V) where you want it to be.

This is slightly cheesy, but I actually did get it to work in SSMS 2008 and I was not able to get any of the other suggestions (control-enter, alt-13, or any alt-##) to work.

How do I display local image in markdown?

Adding a local image worked for me by like so: ![alt text](file://IMG_20181123_115829.jpg)

Without the file:// prefix it did not work (Win10, Notepad++ with MarkdownViewer++ addon)

Edit: I found out it also works with html tags, and that is way better: <img src="file://IMG_20181123_115829.jpg" alt="alt text" width="200"/>

Edit2: In Atom editor it only works without the file:// prefix. What a mess.

Create a CSV File for a user in PHP

First make data as a String with comma as the delimiter (separated with ","). Something like this

$CSV_string="No,Date,Email,Sender Name,Sender Email \n"; //making string, So "\n" is used for newLine

$rand = rand(1,50); //Make a random int number between 1 to 50.
$file ="export/export".$rand.".csv"; //For avoiding cache in the client and on the server 
                                     //side it is recommended that the file name be different.

file_put_contents($file,$CSV_string);

/* Or try this code if $CSV_string is an array
    fh =fopen($file, 'w');
    fputcsv($fh , $CSV_string , ","  , "\n" ); // "," is delimiter // "\n" is new line.
    fclose($fh);
*/

How can I change text color via keyboard shortcut in MS word 2010

Press Alt+H(h) and then you'll see the shortcuts on the toolbar, press FC to operate color menu and press A(Automatic) for black or browse through other colors using arrow keys.

LINK : fatal error LNK1561: entry point must be defined ERROR IN VC++

In my case, the program was running fine, but after one day, I just ran into this problem without doing anything...

The solution was to manually add 'Main' as the Entry Point (before editing, the area was empty):

enter image description here

Installing Python 3 on RHEL

If you want official RHEL packages you can use RHSCL (Red Hat Software Collections)

More details:

You have to have access to Red Hat Customer Portal to read full articles.

Can't connect to docker from docker-compose

WORKING!!
I tried with below commands and its working

service docker restart
docker-compose -f docker_compose.yaml down
docker-compose -f docker_compose.yaml up

ASP.Net MVC: How to display a byte array image from model

If you want to present the image, add a method as a helper class or to the model itself and allow the method to convert the byte array image to a image format like PNG or JPG then convert to Base64 string. Once you have that, bind the base64 value on your view in the format

"data:image/[image file type extension];base64,[your base64 string goes here]"

The above is assigned to the img tag's src attribute.

The only issue I have with this is the base64 string being too long. So, I would not recommend it for multiple models being shown in a view.

Distinct by property of class with LINQ

I think the best option in Terms of performance (or in any terms) is to Distinct using the The IEqualityComparer interface.

Although implementing each time a new comparer for each class is cumbersome and produces boilerplate code.

So here is an extension method which produces a new IEqualityComparer on the fly for any class using reflection.

Usage:

var filtered = taskList.DistinctBy(t => t.TaskExternalId).ToArray();

Extension Method Code

public static class LinqExtensions
{
    public static IEnumerable<T> DistinctBy<T, TKey>(this IEnumerable<T> items, Func<T, TKey> property)
    {
        GeneralPropertyComparer<T, TKey> comparer = new GeneralPropertyComparer<T,TKey>(property);
        return items.Distinct(comparer);
    }   
}
public class GeneralPropertyComparer<T,TKey> : IEqualityComparer<T>
{
    private Func<T, TKey> expr { get; set; }
    public GeneralPropertyComparer (Func<T, TKey> expr)
    {
        this.expr = expr;
    }
    public bool Equals(T left, T right)
    {
        var leftProp = expr.Invoke(left);
        var rightProp = expr.Invoke(right);
        if (leftProp == null && rightProp == null)
            return true;
        else if (leftProp == null ^ rightProp == null)
            return false;
        else
            return leftProp.Equals(rightProp);
    }
    public int GetHashCode(T obj)
    {
        var prop = expr.Invoke(obj);
        return (prop==null)? 0:prop.GetHashCode();
    }
}

SQL update trigger only when column is modified

You want to do the following:

ALTER TRIGGER [dbo].[tr_SCHEDULE_Modified]
   ON [dbo].[SCHEDULE]
   AFTER UPDATE
AS 
BEGIN
SET NOCOUNT ON;

    IF (UPDATE(QtyToRepair))
    BEGIN
        UPDATE SCHEDULE SET modified = GETDATE()
            , ModifiedUser = SUSER_NAME()
            , ModifiedHost = HOST_NAME()
        FROM SCHEDULE S
        INNER JOIN Inserted I ON S.OrderNo = I.OrderNo AND S.PartNumber = I.PartNumber
        WHERE S.QtyToRepair <> I.QtyToRepair
    END
END

Please note that this trigger will fire each time you update the column no matter if the value is the same or not.

Javascript - get array of dates between 2 dates

@softvar's solution, but then including working dates option

/**
 * Returns array of working days between two dates.
 *
 * @param {string} startDate
 *   The start date in yyyy-mm-dd format.
 * @param {string} endDate
 *   The end date in yyyy-mm-dd format.
 * @param {boolean} onlyWorkingDays
 *   If true only working days are returned. Default: false
 *
 * @return {array}
 *   Array of dates in yyyy-mm-dd string format.
 */
function getDates(startDate, stopDate, onlyWorkingDays) {
  let doWd = typeof onlyWorkingDays ==='undefined' ? false : onlyWorkingDays;

  let dateArray = [];  
  let dayNr;
  let runDateObj = moment(startDate);  
  let stopDateObj = moment(stopDate);

  while (runDateObj <= stopDateObj) {
    dayNr = runDateObj.day();
    if (!doWd || (dayNr>0 && dayNr<6)) {
     dateArray.push(moment(runDateObj).format('YYYY-MM-DD'));  
    }

    runDateObj = moment(runDateObj).add(1, 'days');
  }
  return dateArray;
}

Getters \ setters for dummies

In addition to @millimoose's answer, setters can also be used to update other values.

function Name(first, last) {
    this.first = first;
    this.last = last;
}

Name.prototype = {
    get fullName() {
        return this.first + " " + this.last;
    },

    set fullName(name) {
        var names = name.split(" ");
        this.first = names[0];
        this.last = names[1];
    }
};

Now, you can set fullName, and first and last will be updated and vice versa.

n = new Name('Claude', 'Monet')
n.first # "Claude"
n.last # "Monet"
n.fullName # "Claude Monet"
n.fullName = "Gustav Klimt"
n.first # "Gustav"
n.last # "Klimt"

How to while loop until the end of a file in Python without checking for empty line?

Don't loop through a file this way. Instead use a for loop.

for line in f:
    vowel += sum(ch.isvowel() for ch in line)

In fact your whole program is just:

VOWELS = {'A','E','I','O','U','a','e','i','o','u'}
# I'm assuming this is what isvowel checks, unless you're doing something
# fancy to check if 'y' is a vowel
with open('filename.txt') as f:
    vowel = sum(ch in VOWELS for line in f for ch in line.strip())

That said, if you really want to keep using a while loop for some misguided reason:

while True:
    line = f.readline().strip()
    if line == '':
        # either end of file or just a blank line.....
        # we'll assume EOF, because we don't have a choice with the while loop!
        break

Hot to get all form elements values using jQuery?

I know you're using jQuery but for those who want a pure Javascript solution:

// Serialize form fields as URI argument/HTTP POST data
function serializeForm(form) {
    var kvpairs = [];
    for ( var i = 0; i < form.elements.length; i++ ) {
        var e = form.elements[i];
        if(!e.name || !e.value) continue; // Shortcut, may not be suitable for values = 0 (considered as false)
        switch (e.type) {
            case 'text':
            case 'textarea':
            case 'password':
            case 'hidden':
                kvpairs.push(encodeURIComponent(e.name) + "=" + encodeURIComponent(e.value));
                break;
            case 'radio':
            case 'checkbox':
                if (e.checked) kvpairs.push(encodeURIComponent(e.name) + "=" + encodeURIComponent(e.value));
                break;
            /*  To be implemented if needed:
            case 'select-one':
                ... document.forms[x].elements[y].options[0].selected ...
                break;
            case 'select-multiple':
                for (z = 0; z < document.forms[x].elements[y].options.length; z++) {
                    ... document.forms[x].elements[y].options[z].selected ...
                } */
                break;
        }
    }
    return kvpairs.join("&");
}

How can I set the default value for an HTML <select> element?

if you want to use the values from a Form and keep it dynamic try this with php

<form action="../<SamePage>/" method="post">


<?php
    $selected = $_POST['select'];
?>

<select name="select" size="1">

  <option <?php if($selected == '1'){echo("selected");}?>>1</option>
  <option <?php if($selected == '2'){echo("selected");}?>>2</option>

</select>
</form>

Struct memory layout in C

It's implementation-specific, but in practice the rule (in the absence of #pragma pack or the like) is:

  • Struct members are stored in the order they are declared. (This is required by the C99 standard, as mentioned here earlier.)
  • If necessary, padding is added before each struct member, to ensure correct alignment.
  • Each primitive type T requires an alignment of sizeof(T) bytes.

So, given the following struct:

struct ST
{
   char ch1;
   short s;
   char ch2;
   long long ll;
   int i;
};
  • ch1 is at offset 0
  • a padding byte is inserted to align...
  • s at offset 2
  • ch2 is at offset 4, immediately after s
  • 3 padding bytes are inserted to align...
  • ll at offset 8
  • i is at offset 16, right after ll
  • 4 padding bytes are added at the end so that the overall struct is a multiple of 8 bytes. I checked this on a 64-bit system: 32-bit systems may allow structs to have 4-byte alignment.

So sizeof(ST) is 24.

It can be reduced to 16 bytes by rearranging the members to avoid padding:

struct ST
{
   long long ll; // @ 0
   int i;        // @ 8
   short s;      // @ 12
   char ch1;     // @ 14
   char ch2;     // @ 15
} ST;

How to download a file from a website in C#

Sure, you just use a HttpWebRequest.

Once you have the HttpWebRequest set up, you can save the response stream to a file StreamWriter(Either BinaryWriter, or a TextWriter depending on the mimetype.) and you have a file on your hard drive.

EDIT: Forgot about WebClient. That works good unless as long as you only need to use GET to retrieve your file. If the site requires you to POST information to it, you'll have to use a HttpWebRequest, so I'm leaving my answer up.

Jquery - animate height toggle

I just thought to give you the reason why your solution did not work:

When $(document).ready() is executed only the $('#topbar-show') selector can find a matching element from the DOM. The #topbar-show element has not been created yet.

To get past this problem, you may use live event bindings

$('#topbar-show').live('click',function(e){});
$('#topbar-hide').live('click',function(e){});

This is the most simple way to fix you solution. The rest of these answer go further to provide you a better solutions instead that do not modify the hopefully permanent id attribute.

What are my options for storing data when using React Native? (iOS and Android)

you can use sync storage that is easier to use than async storage. this library is great that uses async storage to save data asynchronously and uses memory to load and save data instantly synchronously, so we save data async to memory and use in app sync, so this is great.

import SyncStorage from 'sync-storage';

SyncStorage.set('foo', 'bar');
const result = SyncStorage.get('foo');
console.log(result); // 'bar'

How does MySQL process ORDER BY and LIMIT in a query?

Just as @James says, it will order all records, then get the first 20 rows.

As it is so, you are guaranteed to get the 20 first published articles, the newer ones will not be shown.

In your situation, I recommend that you add desc to order by publish_date, if you want the newest articles, then the newest article will be first.

If you need to keep the result in ascending order, and still only want the 10 newest articles you can ask mysql to sort your result two times.

This query below will sort the result descending and limit the result to 10 (that is the query inside the parenthesis). It will still be sorted in descending order, and we are not satisfied with that, so we ask mysql to sort it one more time. Now we have the newest result on the last row.

select t.article 
from 
    (select article, publish_date 
     from table1
     order by publish_date desc limit 10) t 

order by t.publish_date asc;

If you need all columns, it is done this way:

select t.* 
from 
    (select * 
     from table1  
     order by publish_date desc limit 10) t 

order by t.publish_date asc;

I use this technique when I manually write queries to examine the database for various things. I have not used it in a production environment, but now when I bench marked it, the extra sorting does not impact the performance.

What are major differences between C# and Java?

Generics:

With Java generics, you don't actually get any of the execution efficiency that you get with .NET because when you compile a generic class in Java, the compiler takes away the type parameter and substitutes Object everywhere. For instance if you have a Foo<T> class the java compiler generates Byte Code as if it was Foo<Object>. This means casting and also boxing/unboxing will have to be done in the "background".

I've been playing with Java/C# for a while now and, in my opinion, the major difference at the language level are, as you pointed, delegates.

Codeigniter $this->db->order_by(' ','desc') result is not complete

Put the line $this->db->order_by("course_name","desc"); at top of your query. Like

$this->db->order_by("course_name","desc");$this->db->select('*');
$this->db->where('tennant_id',$tennant_id);
$this->db->from('courses');
$query=$this->db->get();
return $query->result();

Access-Control-Allow-Origin Multiple Origin Domains?

For Nginx users to allow CORS for multiple domains. I like the @marshall's example although his anwers only matches one domain. To match a list of domain and subdomain this regex make it ease to work with fonts:

location ~* \.(?:ttf|ttc|otf|eot|woff|woff2)$ {
   if ( $http_origin ~* (https?://(.+\.)?(domain1|domain2|domain3)\.(?:me|co|com)$) ) {
      add_header "Access-Control-Allow-Origin" "$http_origin";
   }
}

This will only echo "Access-Control-Allow-Origin" headers that matches with the given list of domains.

How to avoid 'undefined index' errors?

A short solution is this (PHP 5.3+):

$output['alternate_title'] = $output['alternate_title'] ?:'';

You get either the value of the variable, if it doesn't evaluate to false, or the false expression. (The one after the ':')

Using the ternary Operator, without the "if true" parameter, will return the result of the test expression (The first one ) Since undefined evaluates to false, the false expression will be returned.

In PHP 7 there is the slightly more elegant Null coalescing operator:

$output['alternate_title'] = $output['alternate_title'] ?? '';

(It would be nice with a default assignment operator like '?=')

Node.js/Windows error: ENOENT, stat 'C:\Users\RT\AppData\Roaming\npm'

I ran into the same problem while installing a package via npm.

After creating the npm folder manually in C:\Users\UserName\AppData\Roaming\ that particular error was gone, but it gave similar multiple errors as it tried to create additional directories in the npm folder and failed. The issue was resolved after running the command prompt as an administrator.

How do I format a number with commas in T-SQL?

SELECT REPLACE(CONVERT(varchar(20), (CAST(9876543 AS money)), 1), '.00', '')

output= 9,876,543

and you can replace 9876543 by your column name.

Dart/Flutter : Converting timestamp

If you are here to just convert Timestamp into DateTime,

Timestamp timestamp = widget.firebaseDocument[timeStampfield];
DateTime date = Timestamp.fromMillisecondsSinceEpoch(
                timestamp.millisecondsSinceEpoch).toDate();

Can the Unix list command 'ls' output numerical chmod permissions?

Closest I can think of (keeping it simple enough) is stat, assuming you know which files you're looking for. If you don't, * can find most of them:

/usr/bin$ stat -c '%a %n' *
755 [
755 a2p
755 a2ps
755 aclocal
...

It handles sticky, suid and company out of the box:

$ stat -c '%a %n' /tmp /usr/bin/sudo
1777 /tmp
4755 /usr/bin/sudo

Unable to copy file - access to the path is denied

Simple Solution:

Just upgrade the following packages

Microsoft.CodeDom.Providers.DotNetCompilerPlatform v1.0.5 to v1.0.7

It will resolve the issue.

What is the difference between x86 and x64

If you download Java Development Kit(JDK) then there is a difference as it contains native libraries which differ for different architectures:

  • x86 is for 32-bit OS
  • x64 is for 64-bit OS

In addition you can use 32-bit JDK(x86) on 64-bit OS. But you can not use 64-bit JDK on 32-bit OS.

At the same time you can run compiled Java classes on any JVM. It does not matter whether it 32 or 64-bit.

What are XAND and XOR

Guys, don´t scare the crap out of others (hey! just kidding), but it´s really all a question of equivalences and synonyms:

firstly:

"XAND" doesn´t exist logically, neither does "XNAND", however "XAND" is normally thought-up by a studious but confused initiating logic student.(wow!). It com from the thought that, if there´s a XOR(exclusive OR) it´s logical to exist a "XAND"("exclusive" AND). The rational suggestion would be an "IAND"("inclusive" AND), which isn´t used or recognised as well. So:

 XNOR <=> !XOR <=> EQV

And all this just discribes a unique operator, called the equivalency operator(<=>, EQV) so:

A  |  B  | A <=> B | A XAND B | A XNOR B | A !XOR B | ((NOT(A) AND B)AND(A AND NOT(B)))
---------------------------------------------------------------------------------------
T  |  T  |    T    |     T    |     T    |     T    |                T    
T  |  F  |    F    |     F    |     F    |     F    |                F    
F  |  T  |    F    |     F    |     F    |     F    |                F    
F  |  F  |    T    |     T    |     T    |     T    |                T    

And just a closing comment: The 'X' prefix is only possible if and only if the base operator isn´t unary. So, XNOR <=> NOT XOR <=/=> X NOR.

Peace.

jQuery DataTables Getting selected row values

You can iterate over the row data

$('#button').click(function () {
    var ids = $.map(table.rows('.selected').data(), function (item) {
        return item[0]
    });
    console.log(ids)
    alert(table.rows('.selected').data().length + ' row(s) selected');
});

Demo: Fiddle

In plain English, what does "git reset" do?

In general, git reset's function is to take the current branch and reset it to point somewhere else, and possibly bring the index and work tree along. More concretely, if your master branch (currently checked out) is like this:

- A - B - C (HEAD, master)

and you realize you want master to point to B, not C, you will use git reset B to move it there:

- A - B (HEAD, master)      # - C is still here, but there's no branch pointing to it anymore

Digression: This is different from a checkout. If you'd run git checkout B, you'd get this:

- A - B (HEAD) - C (master)

You've ended up in a detached HEAD state. HEAD, work tree, index all match B, but the master branch was left behind at C. If you make a new commit D at this point, you'll get this, which is probably not what you want:

- A - B - C (master)
       \
        D (HEAD)

Remember, reset doesn't make commits, it just updates a branch (which is a pointer to a commit) to point to a different commit. The rest is just details of what happens to your index and work tree.

Use cases

I cover many of the main use cases for git reset within my descriptions of the various options in the next section. It can really be used for a wide variety of things; the common thread is that all of them involve resetting the branch, index, and/or work tree to point to/match a given commit.

Things to be careful of

  • --hard can cause you to really lose work. It modifies your work tree.

  • git reset [options] commit can cause you to (sort of) lose commits. In the toy example above, we lost commit C. It's still in the repo, and you can find it by looking at git reflog show HEAD or git reflog show master, but it's not actually accessible from any branch anymore.

  • Git permanently deletes such commits after 30 days, but until then you can recover C by pointing a branch at it again (git checkout C; git branch <new branch name>).

Arguments

Paraphrasing the man page, most common usage is of the form git reset [<commit>] [paths...], which will reset the given paths to their state from the given commit. If the paths aren't provided, the entire tree is reset, and if the commit isn't provided, it's taken to be HEAD (the current commit). This is a common pattern across git commands (e.g. checkout, diff, log, though the exact semantics vary), so it shouldn't be too surprising.

For example, git reset other-branch path/to/foo resets everything in path/to/foo to its state in other-branch, git reset -- . resets the current directory to its state in HEAD, and a simple git reset resets everything to its state in HEAD.

The main work tree and index options

There are four main options to control what happens to your work tree and index during the reset.

Remember, the index is git's "staging area" - it's where things go when you say git add in preparation to commit.

  • --hard makes everything match the commit you've reset to. This is the easiest to understand, probably. All of your local changes get clobbered. One primary use is blowing away your work but not switching commits: git reset --hard means git reset --hard HEAD, i.e. don't change the branch but get rid of all local changes. The other is simply moving a branch from one place to another, and keeping index/work tree in sync. This is the one that can really make you lose work, because it modifies your work tree. Be very very sure you want to throw away local work before you run any reset --hard.

  • --mixed is the default, i.e. git reset means git reset --mixed. It resets the index, but not the work tree. This means all your files are intact, but any differences between the original commit and the one you reset to will show up as local modifications (or untracked files) with git status. Use this when you realize you made some bad commits, but you want to keep all the work you've done so you can fix it up and recommit. In order to commit, you'll have to add files to the index again (git add ...).

  • --soft doesn't touch the index or work tree. All your files are intact as with --mixed, but all the changes show up as changes to be committed with git status (i.e. checked in in preparation for committing). Use this when you realize you've made some bad commits, but the work's all good - all you need to do is recommit it differently. The index is untouched, so you can commit immediately if you want - the resulting commit will have all the same content as where you were before you reset.

  • --merge was added recently, and is intended to help you abort a failed merge. This is necessary because git merge will actually let you attempt a merge with a dirty work tree (one with local modifications) as long as those modifications are in files unaffected by the merge. git reset --merge resets the index (like --mixed - all changes show up as local modifications), and resets the files affected by the merge, but leaves the others alone. This will hopefully restore everything to how it was before the bad merge. You'll usually use it as git reset --merge (meaning git reset --merge HEAD) because you only want to reset away the merge, not actually move the branch. (HEAD hasn't been updated yet, since the merge failed)

    To be more concrete, suppose you've modified files A and B, and you attempt to merge in a branch which modified files C and D. The merge fails for some reason, and you decide to abort it. You use git reset --merge. It brings C and D back to how they were in HEAD, but leaves your modifications to A and B alone, since they weren't part of the attempted merge.

Want to know more?

I do think man git reset is really quite good for this - perhaps you do need a bit of a sense of the way git works for them to really sink in though. In particular, if you take the time to carefully read them, those tables detailing states of files in index and work tree for all the various options and cases are very very helpful. (But yes, they're very dense - they're conveying an awful lot of the above information in a very concise form.)

Strange notation

The "strange notation" (HEAD^ and HEAD~1) you mention is simply a shorthand for specifying commits, without having to use a hash name like 3ebe3f6. It's fully documented in the "specifying revisions" section of the man page for git-rev-parse, with lots of examples and related syntax. The caret and the tilde actually mean different things:

  • HEAD~ is short for HEAD~1 and means the commit's first parent. HEAD~2 means the commit's first parent's first parent. Think of HEAD~n as "n commits before HEAD" or "the nth generation ancestor of HEAD".
  • HEAD^ (or HEAD^1) also means the commit's first parent. HEAD^2 means the commit's second parent. Remember, a normal merge commit has two parents - the first parent is the merged-into commit, and the second parent is the commit that was merged. In general, merges can actually have arbitrarily many parents (octopus merges).
  • The ^ and ~ operators can be strung together, as in HEAD~3^2, the second parent of the third-generation ancestor of HEAD, HEAD^^2, the second parent of the first parent of HEAD, or even HEAD^^^, which is equivalent to HEAD~3.

caret and tilde

Raise an event whenever a property's value changed?

If you change your property to use a backing field (instead of an automatic property), you can do the following:

public event EventHandler ImageFullPath1Changed;
private string _imageFullPath1 = string.Empty;

public string ImageFullPath1 
{
  get
  {
    return imageFullPath1 ;
  }
  set
  {
    if (_imageFullPath1 != value)
    { 
      _imageFullPath1 = value;

      EventHandler handler = ImageFullPathChanged;
      if (handler != null)
        handler(this, e);
    }
  }
}

IntelliJ inspection gives "Cannot resolve symbol" but still compiles code

Invalidate Caches worked for me but after running the application had the same error.

So I tried (Intellij):

1 - Menu bar - Refactor | Build | Run | Tools - click Build then Rebuild Project

2 - MVN clean

3 - Right click on project > Maven > Generate Sources and Update Folder

Hope this works for you.

Thanks

How can I use a DLL file from Python?

For ease of use, ctypes is the way to go.

The following example of ctypes is from actual code I've written (in Python 2.5). This has been, by far, the easiest way I've found for doing what you ask.

import ctypes

# Load DLL into memory.

hllDll = ctypes.WinDLL ("c:\\PComm\\ehlapi32.dll")

# Set up prototype and parameters for the desired function call.
# HLLAPI

hllApiProto = ctypes.WINFUNCTYPE (
    ctypes.c_int,      # Return type.
    ctypes.c_void_p,   # Parameters 1 ...
    ctypes.c_void_p,
    ctypes.c_void_p,
    ctypes.c_void_p)   # ... thru 4.
hllApiParams = (1, "p1", 0), (1, "p2", 0), (1, "p3",0), (1, "p4",0),

# Actually map the call ("HLLAPI(...)") to a Python name.

hllApi = hllApiProto (("HLLAPI", hllDll), hllApiParams)

# This is how you can actually call the DLL function.
# Set up the variables and call the Python name with them.

p1 = ctypes.c_int (1)
p2 = ctypes.c_char_p (sessionVar)
p3 = ctypes.c_int (1)
p4 = ctypes.c_int (0)
hllApi (ctypes.byref (p1), p2, ctypes.byref (p3), ctypes.byref (p4))

The ctypes stuff has all the C-type data types (int, char, short, void*, and so on) and can pass by value or reference. It can also return specific data types although my example doesn't do that (the HLL API returns values by modifying a variable passed by reference).


In terms of the specific example shown above, IBM's EHLLAPI is a fairly consistent interface.

All calls pass four void pointers (EHLLAPI sends the return code back through the fourth parameter, a pointer to an int so, while I specify int as the return type, I can safely ignore it) as per IBM's documentation here. In other words, the C variant of the function would be:

int hllApi (void *p1, void *p2, void *p3, void *p4)

This makes for a single, simple ctypes function able to do anything the EHLLAPI library provides, but it's likely that other libraries will need a separate ctypes function set up per library function.

The return value from WINFUNCTYPE is a function prototype but you still have to set up more parameter information (over and above the types). Each tuple in hllApiParams has a parameter "direction" (1 = input, 2 = output and so on), a parameter name and a default value - see the ctypes doco for details

Once you have the prototype and parameter information, you can create a Python "callable" hllApi with which to call the function. You simply create the needed variable (p1 through p4 in my case) and call the function with them.

How to convert JTextField to String and String to JTextField?

The JTextField offers a getText() and a setText() method - those are for getting and setting the content of the text field.

Quickly create a large file on a Linux system

Linux & all filesystems

xfs_mkfile 10240m 10Gigfile

Linux & and some filesystems (ext4, xfs, btrfs and ocfs2)

fallocate -l 10G 10Gigfile

OS X, Solaris, SunOS and probably other UNIXes

mkfile 10240m 10Gigfile

HP-UX

prealloc 10Gigfile 10737418240

Explanation

Try mkfile <size> myfile as an alternative of dd. With the -n option the size is noted, but disk blocks aren't allocated until data is written to them. Without the -n option, the space is zero-filled, which means writing to the disk, which means taking time.

mkfile is derived from SunOS and is not available everywhere. Most Linux systems have xfs_mkfile which works exactly the same way, and not just on XFS file systems despite the name. It's included in xfsprogs (for Debian/Ubuntu) or similar named packages.

Most Linux systems also have fallocate, which only works on certain file systems (such as btrfs, ext4, ocfs2, and xfs), but is the fastest, as it allocates all the file space (creates non-holey files) but does not initialize any of it.

Which maven dependencies to include for spring 3.0?

You can try this

<dependencies>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>3.1.0.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>3.1.0.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>3.1.0.RELEASE</version>
    </dependency>
</dependencies>`

How do I prevent mails sent through PHP mail() from going to spam?

You must to add a needle headers:

Sample code :

$headers = "From: [email protected]\r\n";
$headers .= "Reply-To: [email protected]\r\n";
$headers .= "Return-Path: [email protected]\r\n";
$headers .= "CC: [email protected]\r\n";
$headers .= "BCC: [email protected]\r\n";

if ( mail($to,$subject,$message,$headers) ) {
   echo "The email has been sent!";
   } else {
   echo "The email has failed!";
   }
?> 

MySQL - UPDATE query based on SELECT Query

UPDATE
    `table1` AS `dest`,
    (
        SELECT
            *
        FROM
            `table2`
        WHERE
            `id` = x
    ) AS `src`
SET
    `dest`.`col1` = `src`.`col1`
WHERE
    `dest`.`id` = x
;

Hope this works for you.

How to add a new line in textarea element?

T.innerText = "Position of LF: " + t.value.indexOf("\n");

p3.innerText = t.value.replace("\n", "");

<textarea id="t">Line 1&#10;Line 2</textarea>

<p id='p3'></p>

Python display text with font & color?

Yes. It is possible to draw text in pygame:

# initialize font; must be called after 'pygame.init()' to avoid 'Font not Initialized' error
myfont = pygame.font.SysFont("monospace", 15)

# render text
label = myfont.render("Some text!", 1, (255,255,0))
screen.blit(label, (100, 100))

To compare two elements(string type) in XSLT?

First of all, the provided long code:

    <xsl:choose>
        <xsl:when test="OU_NAME='OU_ADDR1'">   --comparing two elements coming from XML             
            <!--remove if  adrees already contain  operating unit name <xsl:value-of select="OU_NAME"/> <fo:block/>-->
            <xsl:if test="OU_ADDR1 !='' ">
                <xsl:value-of select="OU_ADDR1"/>
                <fo:block/>
            </xsl:if>
            <xsl:if test="LE_ADDR2 !='' ">
                <xsl:value-of select="OU_ADDR2"/>
                <fo:block/>
            </xsl:if>
            <xsl:if test="LE_ADDR3 !='' ">
                <xsl:value-of select="OU_ADDR3"/>
                <fo:block/>
            </xsl:if>
            <xsl:if test="OU_TOWN_CITY !=''">
                <xsl:value-of select="OU_TOWN_CITY"/>,
                <fo:leader leader-pattern="space" leader-length="2.0pt"/>
            </xsl:if>
            <xsl:value-of select="OU_REGION2"/>
            <fo:leader leader-pattern="space" leader-length="3.0pt"/>
            <xsl:value-of select="OU_POSTALCODE"/>
            <fo:block/>
            <xsl:value-of select="OU_COUNTRY"/>
        </xsl:when>
        <xsl:otherwise>
            <xsl:value-of select="OU_NAME"/>
            <fo:block/>
            <xsl:if test="OU_ADDR1 !='' ">
                <xsl:value-of select="OU_ADDR1"/>
                <fo:block/>
            </xsl:if>
            <xsl:if test="LE_ADDR2 !='' ">
                <xsl:value-of select="OU_ADDR2"/>
                <fo:block/>
            </xsl:if>
            <xsl:if test="LE_ADDR3 !='' ">
                <xsl:value-of select="OU_ADDR3"/>
                <fo:block/>
            </xsl:if>
            <xsl:if test="OU_TOWN_CITY !=''">
                <xsl:value-of select="OU_TOWN_CITY"/>,
                <fo:leader leader-pattern="space" leader-length="2.0pt"/>
            </xsl:if>
            <xsl:value-of select="OU_REGION2"/>
            <fo:leader leader-pattern="space" leader-length="3.0pt"/>
            <xsl:value-of select="OU_POSTALCODE"/>
            <fo:block/>
            <xsl:value-of select="OU_COUNTRY"/>
        </xsl:otherwise>
    </xsl:choose>

is equivalent to this, much shorter code:

<xsl:if test="not(OU_NAME='OU_ADDR1)'">
              <xsl:value-of select="OU_NAME"/>
        </xsl:if>
            <xsl:if test="OU_ADDR1 !='' ">
                <xsl:value-of select="OU_ADDR1"/>
                <fo:block/>
            </xsl:if>
            <xsl:if test="LE_ADDR2 !='' ">
                <xsl:value-of select="OU_ADDR2"/>
                <fo:block/>
            </xsl:if>
            <xsl:if test="LE_ADDR3 !='' ">
                <xsl:value-of select="OU_ADDR3"/>
                <fo:block/>
            </xsl:if>
            <xsl:if test="OU_TOWN_CITY !=''">
                <xsl:value-of select="OU_TOWN_CITY"/>,
                <fo:leader leader-pattern="space" leader-length="2.0pt"/>
            </xsl:if>
            <xsl:value-of select="OU_REGION2"/>
            <fo:leader leader-pattern="space" leader-length="3.0pt"/>
            <xsl:value-of select="OU_POSTALCODE"/>
            <fo:block/>
            <xsl:value-of select="OU_COUNTRY"/>

Now, to your question:

how to compare two elements coming from xml as string

In Xpath 1.0 strings can be compared only for equality (or inequality), using the operator = and the function not() together with the operator =.

$str1 = $str2

evaluates to true() exactly when the string $str1 is equal to the string $str2.

not($str1 = $str2)

evaluates to true() exactly when the string $str1 is not equal to the string $str2.

There is also the != operator. It generally should be avoided because it has anomalous behavior whenever one of its operands is a node-set.

Now, the rules for comparing two element nodes are similar:

$el1 = $el2

evaluates to true() exactly when the string value of $el1 is equal to the string value of $el2.

not($el1 = $el2)

evaluates to true() exactly when the string value of $el1 is not equal to the string value of $el2.

However, if one of the operands of = is a node-set, then

 $ns = $str

evaluates to true() exactly when there is at least one node in the node-set $ns1, whose string value is equal to the string $str

$ns1 = $ns2

evaluates to true() exactly when there is at least one node in the node-set $ns1, whose string value is equal to the string value of some node from $ns2

Therefore, the expression:

OU_NAME='OU_ADDR1'

evaluates to true() only when there is at least one element child of the current node that is named OU_NAME and whose string value is the string 'OU_ADDR1'.

This is obviously not what you want!

Most probably you want:

OU_NAME=OU_ADDR1

This expression evaluates to true exactly there is at least one OU_NAME child of the current node and one OU_ADDR1 child of the current node with the same string value.

Finally, in XPath 2.0, strings can be compared also using the value comparison operators lt, le, eq, gt, ge and the inherited from XPath 1.0 general comparison operator =.

Trying to evaluate a value comparison operator when one or both of its arguments is a sequence of more than one item results in error.

No mapping found for HTTP request with URI Spring MVC

First check whether the java classes are compiled or not in your [PROJECT_NAME]\target\classes directory.

If not you have some compilation errors in your java classes.

Create Pandas DataFrame from a string

A quick and easy solution for interactive work is to copy-and-paste the text by loading the data from the clipboard.

Select the content of the string with your mouse:

Copy data for pasting into a Pandas dataframe

In the Python shell use read_clipboard()

>>> pd.read_clipboard()
  col1;col2;col3
0       1;4.4;99
1      2;4.5;200
2       3;4.7;65
3      4;3.2;140

Use the appropriate separator:

>>> pd.read_clipboard(sep=';')
   col1  col2  col3
0     1   4.4    99
1     2   4.5   200
2     3   4.7    65
3     4   3.2   140

>>> df = pd.read_clipboard(sep=';') # save to dataframe

A top-like utility for monitoring CUDA activity on a GPU

To get real-time insight on used resources, do:

nvidia-smi -l 1

This will loop and call the view at every second.

If you do not want to keep past traces of the looped call in the console history, you can also do:

watch -n0.1 nvidia-smi

Where 0.1 is the time interval, in seconds.

enter image description here

In jQuery how can I set "top,left" properties of an element with position values relative to the parent and not the document?

Refreshing my memory on setting position, I'm coming to this so late I don't know if anyone else will see it, but --

I don't like setting position using css(), though often it's fine. I think the best bet is to use jQuery UI's position() setter as noted by xdazz. However if jQuery UI is, for some reason, not an option (yet jQuery is), I prefer this:

const leftOffset = 200;
const topOffset = 200;
let $div = $("#mydiv");
let baseOffset = $div.offsetParent().offset();
$div.offset({
  left: baseOffset.left + leftOffset,
  top: baseOffset.top + topOffset
});

This has the advantage of not arbitrarily setting $div's parent to relative positioning (what if $div's parent was, itself, absolute positioned inside something else?). I think the only major edge case is if $div doesn't have any offsetParent, not sure if it would return document, null, or something else entirely.

offsetParent has been available since jQuery 1.2.6, sometime in 2008, so this technique works now and when the original question was asked.

Difference between thread's context class loader and normal classloader

There is an article on javaworld.com that explains the difference => Which ClassLoader should you use

(1)

Thread context classloaders provide a back door around the classloading delegation scheme.

Take JNDI for instance: its guts are implemented by bootstrap classes in rt.jar (starting with J2SE 1.3), but these core JNDI classes may load JNDI providers implemented by independent vendors and potentially deployed in the application's -classpath. This scenario calls for a parent classloader (the primordial one in this case) to load a class visible to one of its child classloaders (the system one, for example). Normal J2SE delegation does not work, and the workaround is to make the core JNDI classes use thread context loaders, thus effectively "tunneling" through the classloader hierarchy in the direction opposite to the proper delegation.

(2) from the same source:

This confusion will probably stay with Java for some time. Take any J2SE API with dynamic resource loading of any kind and try to guess which loading strategy it uses. Here is a sampling:

  • JNDI uses context classloaders
  • Class.getResource() and Class.forName() use the current classloader
  • JAXP uses context classloaders (as of J2SE 1.4)
  • java.util.ResourceBundle uses the caller's current classloader
  • URL protocol handlers specified via java.protocol.handler.pkgs system property are looked up in the bootstrap and system classloaders only
  • Java Serialization API uses the caller's current classloader by default

Change color and appearance of drop down arrow

No, you can't do it by using an actual <select>, but there are techniques that allow you to "replace" them with javascript solutions that look better.

Here's a good article on the topic: <select> Something New

Creating a UIImage from a UIColor to use as a background image for UIButton

CGContextSetFillColorWithColor(context,[[UIColor colorWithRed:(255/255.f) green:(0/255.f) blue: (0/255.f) alpha:1] CGColor]);

Select DataFrame rows between two dates

Another option, how to achieve this, is by using pandas.DataFrame.query() method. Let me show you an example on the following data frame called df.

>>> df = pd.DataFrame(np.random.random((5, 1)), columns=['col_1'])
>>> df['date'] = pd.date_range('2020-1-1', periods=5, freq='D')
>>> print(df)
      col_1       date
0  0.015198 2020-01-01
1  0.638600 2020-01-02
2  0.348485 2020-01-03
3  0.247583 2020-01-04
4  0.581835 2020-01-05

As an argument, use the condition for filtering like this:

>>> start_date, end_date = '2020-01-02', '2020-01-04'
>>> print(df.query('date >= @start_date and date <= @end_date'))
      col_1       date
1  0.244104 2020-01-02
2  0.374775 2020-01-03
3  0.510053 2020-01-04

If you do not want to include boundaries, just change the condition like following:

>>> print(df.query('date > @start_date and date < @end_date'))
      col_1       date
2  0.374775 2020-01-03

String or binary data would be truncated. The statement has been terminated

In my case, I was getting this error because my table had

varchar(50)

but I was injecting 67 character long string, which resulted in thi error. Changing it to

varchar(255)

fixed the problem.

Compare two Timestamp in java

From : http://download.oracle.com/javase/6/docs/api/java/sql/Timestamp.html#compareTo(java.sql.Timestamp)

public int compareTo(Timestamp ts)

Compares this Timestamp object to the given Timestamp object. Parameters: ts - the Timestamp object to be compared to this Timestamp object Returns: the value 0 if the two Timestamp objects are equal; a value less than 0 if this Timestamp object is before the given argument; and a value greater than 0 if this Timestamp object is after the given argument. Since: 1.4

What is the difference between Views and Materialized Views in Oracle?

Materialized views are disk based and are updated periodically based upon the query definition.

Views are virtual only and run the query definition each time they are accessed.

How to make exe files from a node.js app?

Got tired of starting on win from command prompt then I ran across this as well. Slightly improved ver. over what josh3736. This uses an XML file to grab a few settings. For example the path to Node.exe as well as the file to start in the default app.js. Also the environment to load (production, dev etc) that you have specified in your app.js (or server.js or whatever you called it). Essentially it adds the NODE_ENV={0} where {0} is the name of your configuration in app.js as a var for you. You do this by modifying the "mode" element in the config.xml. You can grab the project here ==> github. Note in the Post Build events you can modify the copy paths to auto copy over your config.xml and the executable to your Nodejs directory, just to save a step. Otherwise edit these out or your build will throw a warning.

var startInfo = new ProcessStartInfo();
        startInfo.FileName = nodepath;
        startInfo.Arguments = apppath;
        startInfo.UseShellExecute = false;
        startInfo.CreateNoWindow = false;
        startInfo.WindowStyle = ProcessWindowStyle.Hidden;

        if(env.Length > 0)
            startInfo.EnvironmentVariables.Add("NODE_ENV", env);

        try
        {
            using (Process p = Process.Start(startInfo))
            {
                p.WaitForExit();
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message.ToString(), "Start Error", MessageBoxButtons.OK);
        }

How do you split a list into evenly sized chunks?

Yes, it is an old question, but I had to post this one, because it is even a little shorter than the similar ones. Yes, the result looks scrambled, but if it is just about even length...

>>> n = 3 # number of groups
>>> biglist = range(30)
>>>
>>> [ biglist[i::n] for i in xrange(n) ]
[[0, 3, 6, 9, 12, 15, 18, 21, 24, 27],
 [1, 4, 7, 10, 13, 16, 19, 22, 25, 28],
 [2, 5, 8, 11, 14, 17, 20, 23, 26, 29]]

pyplot scatter plot marker size

It is the area of the marker. I mean if you have s1 = 1000 and then s2 = 4000, the relation between the radius of each circle is: r_s2 = 2 * r_s1. See the following plot:

plt.scatter(2, 1, s=4000, c='r')
plt.scatter(2, 1, s=1000 ,c='b')
plt.scatter(2, 1, s=10, c='g')

enter image description here

I had the same doubt when I saw the post, so I did this example then I used a ruler on the screen to measure the radii.

Diff files present in two different directories

If you are only interested to see the files that differ, you may use:

diff -qr dir_one dir_two | sort

Option "q" will only show the files that differ but not the content that differ, and "sort" will arrange the output alphabetically.

How can I read a text file in Android?

Try this

try {
        reader = new BufferedReader(new InputStreamReader(in,"UTF-8"));
    } catch (UnsupportedEncodingException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
      String line="";
      String s ="";
   try 
   {
       line = reader.readLine();
   } 
   catch (IOException e) 
   {
       e.printStackTrace();
   }
      while (line != null) 
      {
       s = s + line;
       s =s+"\n";
       try 
       {
           line = reader.readLine();
       } 
       catch (IOException e) 
       {
           e.printStackTrace();
       }
    }
    tv.setText(""+s);
  }

How can I convert a Timestamp into either Date or DateTime object?

java.sql.Timestamp is a subclass of java.util.Date. So, just upcast it.

Date dtStart = resultSet.getTimestamp("dtStart");
Date dtEnd = resultSet.getTimestamp("dtEnd");

Using SimpleDateFormat and creating Joda DateTime should be straightforward from this point on.

In practice, what are the main uses for the new "yield from" syntax in Python 3.3?

A short example will help you understand one of yield from's use case: get value from another generator

def flatten(sequence):
    """flatten a multi level list or something
    >>> list(flatten([1, [2], 3]))
    [1, 2, 3]
    >>> list(flatten([1, [2], [3, [4]]]))
    [1, 2, 3, 4]
    """
    for element in sequence:
        if hasattr(element, '__iter__'):
            yield from flatten(element)
        else:
            yield element

print(list(flatten([1, [2], [3, [4]]])))

Key value pairs using JSON

I see what you are trying to ask and I think this is the simplest answer to what you are looking for, given you might not know how many key pairs your are being sent.

Simple Key Pair JSON structure

var data = {
    'XXXXXX' : '100.0',
    'YYYYYYY' : '200.0',
    'ZZZZZZZ' : '500.0',
}

Usage JavaScript code to access the key pairs

for (var key in data) 
  { if (!data.hasOwnProperty(key))
    { continue; } 
    console.log(key + ' -> ' +  data[key]);
  };

Console output should look like this

XXXXXX -> 100.0 
YYYYYYY -> 200.0 
ZZZZZZZ -> 500.0

Here is a JSFiddle to show how it works.

How to get JSON data from the URL (REST API) to UI using jQuery or plain JavaScript?

You can use us jquery function getJson :

$(function(){
    $.getJSON('/api/rest/abc', function(data) {
        console.log(data);
    });
});

How to reload page the page with pagination in Angular 2?

This should technically be achievable using window.location.reload():

HTML:

<button (click)="refresh()">Refresh</button>

TS:

refresh(): void {
    window.location.reload();
}

Update:

Here is a basic StackBlitz example showing the refresh in action. Notice the URL on "/hello" path is retained when window.location.reload() is executed.

What is the right way to debug in iPython notebook?

You can use ipdb inside jupyter with:

from IPython.core.debugger import Tracer; Tracer()()

Edit: the functions above are deprecated since IPython 5.1. This is the new approach:

from IPython.core.debugger import set_trace

Add set_trace() where you need a breakpoint. Type help for ipdb commands when the input field appears.

How to wrap text of HTML button with fixed width?

white-space: normal;
word-wrap: break-word;

Mine works with both

The number of method references in a .dex file cannot exceed 64k API 17

This is what worked for me:

This happens because there are too many unused methods. Most of these methods are coming from included libraries in your build.gradle

Use minify and shrink resources to fix this with gradle and clean up your code at the same time.

buildTypes {
        release {
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
        debug {
            minifyEnabled true
            shrinkResources true
        }
    }

Set Google Chrome as the debugging browser in Visual Studio

To add something to this (cause I found it while searching on this problem, and my solution involved slightly more)...

If you don't have a "Browse with..." option for .aspx files (as I didn't in a MVC application), the easiest solution is to add a dummy HTML file, and right-click it to set the option as described in the answer. You can remove the file afterward.

The option is actually set in: C:\Documents and Settings[user]\Local Settings\Application Data\Microsoft\VisualStudio[version]\browser.xml

However, if you modify the file directly while VS is running, VS will overwrite it with your previous option on next run. Also, if you edit the default in VS you won't have to worry about getting the schema right, so the work-around dummy file is probably the easiest way.

Bootstrap Align Image with text

use the grid-system of boostrap , more information here

for example

<div class="row">
  <div class="col-md-4">here img</div>
  <div class="col-md-4">here text</div>
</div>

in this way when the page will shrink the second div(the text) will be found under the first(the image)

Count unique values using pandas groupby

This is just an add-on to the solution in case you want to compute not only unique values but other aggregate functions:

df.groupby(['group']).agg(['min','max','count','nunique'])

Hope you find it useful

how to compare two string dates in javascript?

Parse the dates and compare them as you would numbers:

function isLater(str1, str2)
{
    return new Date(str1) > new Date(str2);
}

If you need to support other date format consider a library such as date.js.

How can I move all the files from one folder to another using the command line?

Be sure to use quotes if there are spaces in the file path:

move "C:\Users\MyName\My Old Folder\*" "C:\Users\MyName\My New Folder"

That will move the contents of C:\Users\MyName\My Old Folder\ to C:\Users\MyName\My New Folder

How to call a function, PostgreSQL

you declare your function as returning boolean, but it never returns anything.

How to select an element inside "this" in jQuery?

$( this ).find( 'li.target' ).css("border", "3px double red");

or

$( this ).children( 'li.target' ).css("border", "3px double red");

Use children for immediate descendants, or find for deeper elements.

How can prevent a PowerShell window from closing so I can see the error?

The simplest and easiest way is to execute your particular script with -NoExit param.

1.Open run box by pressing:

Win + R

2.Then type into input prompt:

PowerShell -NoExit "C:\folder\script.ps1"

and execute.

How do you create a UIImage View Programmatically - Swift

First you create a UIImage from your image file, then create a UIImageView from that:

let imageName = "yourImage.png"
let image = UIImage(named: imageName)
let imageView = UIImageView(image: image!)

Finally you'll need to give imageView a frame and add it your view for it to be visible:

imageView.frame = CGRect(x: 0, y: 0, width: 100, height: 200)
view.addSubview(imageView)

How do SO_REUSEADDR and SO_REUSEPORT differ?

Welcome to the wonderful world of portability... or rather the lack of it. Before we start analyzing these two options in detail and take a deeper look how different operating systems handle them, it should be noted that the BSD socket implementation is the mother of all socket implementations. Basically all other systems copied the BSD socket implementation at some point in time (or at least its interfaces) and then started evolving it on their own. Of course the BSD socket implementation was evolved as well at the same time and thus systems that copied it later got features that were lacking in systems that copied it earlier. Understanding the BSD socket implementation is the key to understanding all other socket implementations, so you should read about it even if you don't care to ever write code for a BSD system.

There are a couple of basics you should know before we look at these two options. A TCP/UDP connection is identified by a tuple of five values:

{<protocol>, <src addr>, <src port>, <dest addr>, <dest port>}

Any unique combination of these values identifies a connection. As a result, no two connections can have the same five values, otherwise the system would not be able to distinguish these connections any longer.

The protocol of a socket is set when a socket is created with the socket() function. The source address and port are set with the bind() function. The destination address and port are set with the connect() function. Since UDP is a connectionless protocol, UDP sockets can be used without connecting them. Yet it is allowed to connect them and in some cases very advantageous for your code and general application design. In connectionless mode, UDP sockets that were not explicitly bound when data is sent over them for the first time are usually automatically bound by the system, as an unbound UDP socket cannot receive any (reply) data. Same is true for an unbound TCP socket, it is automatically bound before it will be connected.

If you explicitly bind a socket, it is possible to bind it to port 0, which means "any port". Since a socket cannot really be bound to all existing ports, the system will have to choose a specific port itself in that case (usually from a predefined, OS specific range of source ports). A similar wildcard exists for the source address, which can be "any address" (0.0.0.0 in case of IPv4 and :: in case of IPv6). Unlike in case of ports, a socket can really be bound to "any address" which means "all source IP addresses of all local interfaces". If the socket is connected later on, the system has to choose a specific source IP address, since a socket cannot be connected and at the same time be bound to any local IP address. Depending on the destination address and the content of the routing table, the system will pick an appropriate source address and replace the "any" binding with a binding to the chosen source IP address.

By default, no two sockets can be bound to the same combination of source address and source port. As long as the source port is different, the source address is actually irrelevant. Binding socketA to ipA:portA and socketB to ipB:portB is always possible if ipA != ipB holds true, even when portA == portB. E.g. socketA belongs to a FTP server program and is bound to 192.168.0.1:21 and socketB belongs to another FTP server program and is bound to 10.0.0.1:21, both bindings will succeed. Keep in mind, though, that a socket may be locally bound to "any address". If a socket is bound to 0.0.0.0:21, it is bound to all existing local addresses at the same time and in that case no other socket can be bound to port 21, regardless which specific IP address it tries to bind to, as 0.0.0.0 conflicts with all existing local IP addresses.

Anything said so far is pretty much equal for all major operating system. Things start to get OS specific when address reuse comes into play. We start with BSD, since as I said above, it is the mother of all socket implementations.

BSD

SO_REUSEADDR

If SO_REUSEADDR is enabled on a socket prior to binding it, the socket can be successfully bound unless there is a conflict with another socket bound to exactly the same combination of source address and port. Now you may wonder how is that any different than before? The keyword is "exactly". SO_REUSEADDR mainly changes the way how wildcard addresses ("any IP address") are treated when searching for conflicts.

Without SO_REUSEADDR, binding socketA to 0.0.0.0:21 and then binding socketB to 192.168.0.1:21 will fail (with error EADDRINUSE), since 0.0.0.0 means "any local IP address", thus all local IP addresses are considered in use by this socket and this includes 192.168.0.1, too. With SO_REUSEADDR it will succeed, since 0.0.0.0 and 192.168.0.1 are not exactly the same address, one is a wildcard for all local addresses and the other one is a very specific local address. Note that the statement above is true regardless in which order socketA and socketB are bound; without SO_REUSEADDR it will always fail, with SO_REUSEADDR it will always succeed.

To give you a better overview, let's make a table here and list all possible combinations:

SO_REUSEADDR       socketA        socketB       Result
---------------------------------------------------------------------
  ON/OFF       192.168.0.1:21   192.168.0.1:21    Error (EADDRINUSE)
  ON/OFF       192.168.0.1:21      10.0.0.1:21    OK
  ON/OFF          10.0.0.1:21   192.168.0.1:21    OK
   OFF             0.0.0.0:21   192.168.1.0:21    Error (EADDRINUSE)
   OFF         192.168.1.0:21       0.0.0.0:21    Error (EADDRINUSE)
   ON              0.0.0.0:21   192.168.1.0:21    OK
   ON          192.168.1.0:21       0.0.0.0:21    OK
  ON/OFF           0.0.0.0:21       0.0.0.0:21    Error (EADDRINUSE)

The table above assumes that socketA has already been successfully bound to the address given for socketA, then socketB is created, either gets SO_REUSEADDR set or not, and finally is bound to the address given for socketB. Result is the result of the bind operation for socketB. If the first column says ON/OFF, the value of SO_REUSEADDR is irrelevant to the result.

Okay, SO_REUSEADDR has an effect on wildcard addresses, good to know. Yet that isn't it's only effect it has. There is another well known effect which is also the reason why most people use SO_REUSEADDR in server programs in the first place. For the other important use of this option we have to take a deeper look on how the TCP protocol works.

A socket has a send buffer and if a call to the send() function succeeds, it does not mean that the requested data has actually really been sent out, it only means the data has been added to the send buffer. For UDP sockets, the data is usually sent pretty soon, if not immediately, but for TCP sockets, there can be a relatively long delay between adding data to the send buffer and having the TCP implementation really send that data. As a result, when you close a TCP socket, there may still be pending data in the send buffer, which has not been sent yet but your code considers it as sent, since the send() call succeeded. If the TCP implementation was closing the socket immediately on your request, all of this data would be lost and your code wouldn't even know about that. TCP is said to be a reliable protocol and losing data just like that is not very reliable. That's why a socket that still has data to send will go into a state called TIME_WAIT when you close it. In that state it will wait until all pending data has been successfully sent or until a timeout is hit, in which case the socket is closed forcefully.

At most, the amount of time the kernel will wait before it closes the socket, regardless if it still has data in flight or not, is called the Linger Time. The Linger Time is globally configurable on most systems and by default rather long (two minutes is a common value you will find on many systems). It is also configurable per socket using the socket option SO_LINGER which can be used to make the timeout shorter or longer, and even to disable it completely. Disabling it completely is a very bad idea, though, since closing a TCP socket gracefully is a slightly complex process and involves sending forth and back a couple of packets (as well as resending those packets in case they got lost) and this whole close process is also limited by the Linger Time. If you disable lingering, your socket may not only lose data in flight, it is also always closed forcefully instead of gracefully, which is usually not recommended. The details about how a TCP connection is closed gracefully are beyond the scope of this answer, if you want to learn more about, I recommend you have a look at this page. And even if you disabled lingering with SO_LINGER, if your process dies without explicitly closing the socket, BSD (and possibly other systems) will linger nonetheless, ignoring what you have configured. This will happen for example if your code just calls exit() (pretty common for tiny, simple server programs) or the process is killed by a signal (which includes the possibility that it simply crashes because of an illegal memory access). So there is nothing you can do to make sure a socket will never linger under all circumstances.

The question is, how does the system treat a socket in state TIME_WAIT? If SO_REUSEADDR is not set, a socket in state TIME_WAIT is considered to still be bound to the source address and port and any attempt to bind a new socket to the same address and port will fail until the socket has really been closed, which may take as long as the configured Linger Time. So don't expect that you can rebind the source address of a socket immediately after closing it. In most cases this will fail. However, if SO_REUSEADDR is set for the socket you are trying to bind, another socket bound to the same address and port in state TIME_WAIT is simply ignored, after all its already "half dead", and your socket can bind to exactly the same address without any problem. In that case it plays no role that the other socket may have exactly the same address and port. Note that binding a socket to exactly the same address and port as a dying socket in TIME_WAIT state can have unexpected, and usually undesired, side effects in case the other socket is still "at work", but that is beyond the scope of this answer and fortunately those side effects are rather rare in practice.

There is one final thing you should know about SO_REUSEADDR. Everything written above will work as long as the socket you want to bind to has address reuse enabled. It is not necessary that the other socket, the one which is already bound or is in a TIME_WAIT state, also had this flag set when it was bound. The code that decides if the bind will succeed or fail only inspects the SO_REUSEADDR flag of the socket fed into the bind() call, for all other sockets inspected, this flag is not even looked at.

SO_REUSEPORT

SO_REUSEPORT is what most people would expect SO_REUSEADDR to be. Basically, SO_REUSEPORT allows you to bind an arbitrary number of sockets to exactly the same source address and port as long as all prior bound sockets also had SO_REUSEPORT set before they were bound. If the first socket that is bound to an address and port does not have SO_REUSEPORT set, no other socket can be bound to exactly the same address and port, regardless if this other socket has SO_REUSEPORT set or not, until the first socket releases its binding again. Unlike in case of SO_REUESADDR the code handling SO_REUSEPORT will not only verify that the currently bound socket has SO_REUSEPORT set but it will also verify that the socket with a conflicting address and port had SO_REUSEPORT set when it was bound.

SO_REUSEPORT does not imply SO_REUSEADDR. This means if a socket did not have SO_REUSEPORT set when it was bound and another socket has SO_REUSEPORT set when it is bound to exactly the same address and port, the bind fails, which is expected, but it also fails if the other socket is already dying and is in TIME_WAIT state. To be able to bind a socket to the same addresses and port as another socket in TIME_WAIT state requires either SO_REUSEADDR to be set on that socket or SO_REUSEPORT must have been set on both sockets prior to binding them. Of course it is allowed to set both, SO_REUSEPORT and SO_REUSEADDR, on a socket.

There is not much more to say about SO_REUSEPORT other than that it was added later than SO_REUSEADDR, that's why you will not find it in many socket implementations of other systems, which "forked" the BSD code before this option was added, and that there was no way to bind two sockets to exactly the same socket address in BSD prior to this option.

Connect() Returning EADDRINUSE?

Most people know that bind() may fail with the error EADDRINUSE, however, when you start playing around with address reuse, you may run into the strange situation that connect() fails with that error as well. How can this be? How can a remote address, after all that's what connect adds to a socket, be already in use? Connecting multiple sockets to exactly the same remote address has never been a problem before, so what's going wrong here?

As I said on the very top of my reply, a connection is defined by a tuple of five values, remember? And I also said, that these five values must be unique otherwise the system cannot distinguish two connections any longer, right? Well, with address reuse, you can bind two sockets of the same protocol to the same source address and port. That means three of those five values are already the same for these two sockets. If you now try to connect both of these sockets also to the same destination address and port, you would create two connected sockets, whose tuples are absolutely identical. This cannot work, at least not for TCP connections (UDP connections are no real connections anyway). If data arrived for either one of the two connections, the system could not tell which connection the data belongs to. At least the destination address or destination port must be different for either connection, so that the system has no problem to identify to which connection incoming data belongs to.

So if you bind two sockets of the same protocol to the same source address and port and try to connect them both to the same destination address and port, connect() will actually fail with the error EADDRINUSE for the second socket you try to connect, which means that a socket with an identical tuple of five values is already connected.

Multicast Addresses

Most people ignore the fact that multicast addresses exist, but they do exist. While unicast addresses are used for one-to-one communication, multicast addresses are used for one-to-many communication. Most people got aware of multicast addresses when they learned about IPv6 but multicast addresses also existed in IPv4, even though this feature was never widely used on the public Internet.

The meaning of SO_REUSEADDR changes for multicast addresses as it allows multiple sockets to be bound to exactly the same combination of source multicast address and port. In other words, for multicast addresses SO_REUSEADDR behaves exactly as SO_REUSEPORT for unicast addresses. Actually, the code treats SO_REUSEADDR and SO_REUSEPORT identically for multicast addresses, that means you could say that SO_REUSEADDR implies SO_REUSEPORT for all multicast addresses and the other way round.


FreeBSD/OpenBSD/NetBSD

All these are rather late forks of the original BSD code, that's why they all three offer the same options as BSD and they also behave the same way as in BSD.


macOS (MacOS X)

At its core, macOS is simply a BSD-style UNIX named "Darwin", based on a rather late fork of the BSD code (BSD 4.3), which was then later on even re-synchronized with the (at that time current) FreeBSD 5 code base for the Mac OS 10.3 release, so that Apple could gain full POSIX compliance (macOS is POSIX certified). Despite having a microkernel at its core ("Mach"), the rest of the kernel ("XNU") is basically just a BSD kernel, and that's why macOS offers the same options as BSD and they also behave the same way as in BSD.

iOS / watchOS / tvOS

iOS is just a macOS fork with a slightly modified and trimmed kernel, somewhat stripped down user space toolset and a slightly different default framework set. watchOS and tvOS are iOS forks, that are stripped down even further (especially watchOS). To my best knowledge they all behave exactly as macOS does.


Linux

Linux < 3.9

Prior to Linux 3.9, only the option SO_REUSEADDR existed. This option behaves generally the same as in BSD with two important exceptions:

  1. As long as a listening (server) TCP socket is bound to a specific port, the SO_REUSEADDR option is entirely ignored for all sockets targeting that port. Binding a second socket to the same port is only possible if it was also possible in BSD without having SO_REUSEADDR set. E.g. you cannot bind to a wildcard address and then to a more specific one or the other way round, both is possible in BSD if you set SO_REUSEADDR. What you can do is you can bind to the same port and two different non-wildcard addresses, as that's always allowed. In this aspect Linux is more restrictive than BSD.

  2. The second exception is that for client sockets, this option behaves exactly like SO_REUSEPORT in BSD, as long as both had this flag set before they were bound. The reason for allowing that was simply that it is important to be able to bind multiple sockets to exactly to the same UDP socket address for various protocols and as there used to be no SO_REUSEPORT prior to 3.9, the behavior of SO_REUSEADDR was altered accordingly to fill that gap. In that aspect Linux is less restrictive than BSD.

Linux >= 3.9

Linux 3.9 added the option SO_REUSEPORT to Linux as well. This option behaves exactly like the option in BSD and allows binding to exactly the same address and port number as long as all sockets have this option set prior to binding them.

Yet, there are still two differences to SO_REUSEPORT on other systems:

  1. To prevent "port hijacking", there is one special limitation: All sockets that want to share the same address and port combination must belong to processes that share the same effective user ID! So one user cannot "steal" ports of another user. This is some special magic to somewhat compensate for the missing SO_EXCLBIND/SO_EXCLUSIVEADDRUSE flags.

  2. Additionally the kernel performs some "special magic" for SO_REUSEPORT sockets that isn't found in other operating systems: For UDP sockets, it tries to distribute datagrams evenly, for TCP listening sockets, it tries to distribute incoming connect requests (those accepted by calling accept()) evenly across all the sockets that share the same address and port combination. Thus an application can easily open the same port in multiple child processes and then use SO_REUSEPORT to get a very inexpensive load balancing.


Android

Even though the whole Android system is somewhat different from most Linux distributions, at its core works a slightly modified Linux kernel, thus everything that applies to Linux should apply to Android as well.


Windows

Windows only knows the SO_REUSEADDR option, there is no SO_REUSEPORT. Setting SO_REUSEADDR on a socket in Windows behaves like setting SO_REUSEPORT and SO_REUSEADDR on a socket in BSD, with one exception:

Prior to Windows 2003, a socket with SO_REUSEADDR could always been bound to exactly the same source address and port as an already bound socket, even if the other socket did not have this option set when it was bound. This behavior allowed an application "to steal" the connected port of another application. Needless to say that this has major security implications!

Microsoft realized that and added another important socket option: SO_EXCLUSIVEADDRUSE. Setting SO_EXCLUSIVEADDRUSE on a socket makes sure that if the binding succeeds, the combination of source address and port is owned exclusively by this socket and no other socket can bind to them, not even if it has SO_REUSEADDR set.

This default behavior was changed first in Windows 2003, Microsoft calls that "Enhanced Socket Security" (funny name for a behavior that is default on all other major operating systems). For more details just visit this page. There are three tables: The first one shows the classic behavior (still in use when using compatibility modes!), the second one shows the behavior of Windows 2003 and up when the bind() calls are made by the same user, and the third one when the bind() calls are made by different users.


Solaris

Solaris is the successor of SunOS. SunOS was originally based on a fork of BSD, SunOS 5 and later was based on a fork of SVR4, however SVR4 is a merge of BSD, System V, and Xenix, so up to some degree Solaris is also a BSD fork, and a rather early one. As a result Solaris only knows SO_REUSEADDR, there is no SO_REUSEPORT. The SO_REUSEADDR behaves pretty much the same as it does in BSD. As far as I know there is no way to get the same behavior as SO_REUSEPORT in Solaris, that means it is not possible to bind two sockets to exactly the same address and port.

Similar to Windows, Solaris has an option to give a socket an exclusive binding. This option is named SO_EXCLBIND. If this option is set on a socket prior to binding it, setting SO_REUSEADDR on another socket has no effect if the two sockets are tested for an address conflict. E.g. if socketA is bound to a wildcard address and socketB has SO_REUSEADDR enabled and is bound to a non-wildcard address and the same port as socketA, this bind will normally succeed, unless socketA had SO_EXCLBIND enabled, in which case it will fail regardless the SO_REUSEADDR flag of socketB.


Other Systems

In case your system is not listed above, I wrote a little test program that you can use to find out how your system handles these two options. Also if you think my results are wrong, please first run that program before posting any comments and possibly making false claims.

All that the code requires to build is a bit POSIX API (for the network parts) and a C99 compiler (actually most non-C99 compiler will work as well as long as they offer inttypes.h and stdbool.h; e.g. gcc supported both long before offering full C99 support).

All that the program needs to run is that at least one interface in your system (other than the local interface) has an IP address assigned and that a default route is set which uses that interface. The program will gather that IP address and use it as the second "specific address".

It tests all possible combinations you can think of:

  • TCP and UDP protocol
  • Normal sockets, listen (server) sockets, multicast sockets
  • SO_REUSEADDR set on socket1, socket2, or both sockets
  • SO_REUSEPORT set on socket1, socket2, or both sockets
  • All address combinations you can make out of 0.0.0.0 (wildcard), 127.0.0.1 (specific address), and the second specific address found at your primary interface (for multicast it's just 224.1.2.3 in all tests)

and prints the results in a nice table. It will also work on systems that don't know SO_REUSEPORT, in which case this option is simply not tested.

What the program cannot easily test is how SO_REUSEADDR acts on sockets in TIME_WAIT state as it's very tricky to force and keep a socket in that state. Fortunately most operating systems seems to simply behave like BSD here and most of the time programmers can simply ignore the existence of that state.

Here's the code (I cannot include it here, answers have a size limit and the code would push this reply over the limit).

How to automatically insert a blank row after a group of data

Just an idea, if you know the categories, as small, medium, and large mentioned above...

At the bottom of the sheet, make 3 rows that only say small, medium, and large, change the font to white, and then sort so that it alphabetizes, placing a blank row between each section.

How can I pop-up a print dialog box using Javascript?

window.print();  

unless you mean a custom looking popup.

How can one tell the version of React running at runtime in the browser?

In index.js file, simply replace App component with "React.version". E.g.

ReactDOM.render(React.version, document.getElementById('root'));

I have checked this with React v16.8.1

How do I get the directory from a file's full path?

You can use Path.GetDirectoryName and just pass in the filename.

MSDN Link

'any' vs 'Object'

Contrary to .NET where all types derive from an "object", in TypeScript, all types derive from "any". I just wanted to add this comparison as I think it will be a common one made as more .NET developers give TypeScript a try.

Matplotlib: ValueError: x and y must have same first dimension

Changing your lists to numpy arrays will do the job!!

import matplotlib.pyplot as plt
from scipy import stats
import numpy as np 

x = np.array([0.46,0.59,0.68,0.99,0.39,0.31,1.09,0.77,0.72,0.49,0.55,0.62,0.58,0.88,0.78]) # x is a numpy array now
y = np.array([0.315,0.383,0.452,0.650,0.279,0.215,0.727,0.512,0.478,0.335,0.365,0.424,0.390,0.585,0.511]) # y is a numpy array now
xerr = [0.01]*15
yerr = [0.001]*15

plt.rc('font', family='serif', size=13)
m, b = np.polyfit(x, y, 1)
plt.plot(x,y,'s',color='#0066FF')
plt.plot(x, m*x + b, 'r-') #BREAKS ON THIS LINE
plt.errorbar(x,y,xerr=xerr,yerr=0,linestyle="None",color='black')
plt.xlabel('$\Delta t$ $(s)$',fontsize=20)
plt.ylabel('$\Delta p$ $(hPa)$',fontsize=20)
plt.autoscale(enable=True, axis=u'both', tight=False)
plt.grid(False)
plt.xlim(0.2,1.2)
plt.ylim(0,0.8)
plt.show()

enter image description here

How to force C# .net app to run only one instance in Windows?

This is what I use in my application:

static void Main()
{
  bool mutexCreated = false;
  System.Threading.Mutex mutex = new System.Threading.Mutex( true, @"Local\slimCODE.slimKEYS.exe", out mutexCreated );

  if( !mutexCreated )
  {
    if( MessageBox.Show(
      "slimKEYS is already running. Hotkeys cannot be shared between different instances. Are you sure you wish to run this second instance?",
      "slimKEYS already running",
      MessageBoxButtons.YesNo,
      MessageBoxIcon.Question ) != DialogResult.Yes )
    {
      mutex.Close();
      return;
    }
  }

  // The usual stuff with Application.Run()

  mutex.Close();
}

twitter bootstrap autocomplete dropdown / combobox with Knockoutjs

Can i suggest http://www.jqueryscript.net/form/Twitter-Like-Mentions-Auto-Suggesting-Plugin-with-jQuery-Bootstrap-Suggest.html, works more like the twitter post suggestion where it gives you a list of users or topics based on @ or # tags,

view demo here: http://www.jqueryscript.net/demo/Twitter-Like-Mentions-Auto-Suggesting-Plugin-with-jQuery-Bootstrap-Suggest/

in this one you can easily change the @ and # to anything you want

How to resolve this JNI error when trying to run LWJGL "Hello World"?

I had same issue using different dependancy what helped me is to set scope to compile.

<dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.0.1</version>
        <scope>compile</scope>
    </dependency>

Remove last characters from a string in C#. An elegant way?

Use:

public static class StringExtensions
{
    /// <summary>
    /// Cut End. "12".SubstringFromEnd(1) -> "1"
    /// </summary>
    public static string SubstringFromEnd(this string value, int startindex)
    {
        if (string.IsNullOrEmpty(value)) return value;
        return value.Substring(0, value.Length - startindex);
    }
}

I prefer an extension method here for two reasons:

  1. I can chain it with Substring. Example: f1.Substring(directorypathLength).SubstringFromEnd(1)
  2. Speed.

Extract a substring using PowerShell

Building on Matt's answer, here's one that searches across newlines and is easy to modify for your own use

$String="----start----`nHello World`n----end----"
$SearchStart="----start----`n" #Will not be included in results
$SearchEnd="`n----end----" #Will not be included in results
$String -match "(?s)$SearchStart(?<content>.*)$SearchEnd"
$result=$matches['content']
$result

--

NOTE: if you want to run this against a file keep in mind Get-Content returns an array not a single string. You can work around this by doing the following:

$String=[string]::join("`n", (Get-Content $Filename))

org.springframework.web.client.HttpClientErrorException: 400 Bad Request

This is what worked for me. Issue is earlier I didn't set Content Type(header) when I used exchange method.

MultiValueMap<String, String> map = new LinkedMultiValueMap<String, String>();
map.add("param1", "123");
map.add("param2", "456");
map.add("param3", "789");
map.add("param4", "123");
map.add("param5", "456");

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

final HttpEntity<MultiValueMap<String, String>> entity = new HttpEntity<MultiValueMap<String, String>>(map ,
        headers);
JSONObject jsonObject = null;

try {
    RestTemplate restTemplate = new RestTemplate();
    ResponseEntity<String> responseEntity = restTemplate.exchange(
            "https://url", HttpMethod.POST, entity,
            String.class);

    if (responseEntity.getStatusCode() == HttpStatus.CREATED) {
        try {
            jsonObject = new JSONObject(responseEntity.getBody());
        } catch (JSONException e) {
            throw new RuntimeException("JSONException occurred");
        }
    }
  } catch (final HttpClientErrorException httpClientErrorException) {
        throw new ExternalCallBadRequestException();
  } catch (HttpServerErrorException httpServerErrorException) {
        throw new ExternalCallServerErrorException(httpServerErrorException);
  } catch (Exception exception) {
        throw new ExternalCallServerErrorException(exception);
    } 

ExternalCallBadRequestException and ExternalCallServerErrorException are the custom exceptions here.

Note: Remember HttpClientErrorException is thrown when a 4xx error is received. So if the request you send is wrong either setting header or sending wrong data, you could receive this exception.

How to create a sticky navigation bar that becomes fixed to the top after scrolling

This worked great for me. Don't forget to put a filler div in there where the navigation bar used to be, or else the content will jump every time it's fixed/unfixed.

function setSkrollr(){
    var objDistance = $navbar.offset().top;
    $(window).scroll(function() {
        var myDistance = $(window).scrollTop();
        if (myDistance > objDistance){
            $navbar.addClass('navbar-fixed-top');
        }
        if (objDistance > myDistance){
            $navbar.removeClass('navbar-fixed-top');
        }
    });
}

Django: save() vs update() to update the database?

Update will give you better performance with a queryset of more than one object, as it will make one database call per queryset.

However save is useful, as it is easy to override the save method in your model and add extra logic there. In my own application for example, I update a dates when other fields are changed.

Class myModel(models.Model): 
    name = models.CharField()
    date_created = models.DateField()

    def save(self):
        if not self.pk :
           ### we have a newly created object, as the db id is not set
           self.date_created = datetime.datetime.now()
        super(myModel , self).save()

linux execute command remotely

If you don't want to deal with security and want to make it as exposed (aka "convenient") as possible for short term, and|or don't have ssh/telnet or key generation on all your hosts, you can can hack a one-liner together with netcat. Write a command to your target computer's port over the network and it will run it. Then you can block access to that port to a few "trusted" users or wrap it in a script that only allows certain commands to run. And use a low privilege user.

on the server

mkfifo /tmp/netfifo; nc -lk 4201 0</tmp/netfifo | bash -e &>/tmp/netfifo

This one liner reads whatever string you send into that port and pipes it into bash to be executed. stderr & stdout are dumped back into netfifo and sent back to the connecting host via nc.

on the client

To run a command remotely: echo "ls" | nc HOST 4201

Using the passwd command from within a shell script

Tested this on a CentOS VMWare image that I keep around for this sort of thing. Note that you probably want to avoid putting passwords as command-line arguments, because anybody on the entire machine can read them out of 'ps -ef'.

That said, this will work:

user="$1"
password="$2"
adduser $user
echo $password | passwd --stdin $user

Get bytes from std::string in C++

If you just need read-only access, then c_str() will do it:

char const *c = myString.c_str();

If you need read/write access, then you can copy the string into a vector. vectors manage dynamic memory for you. You don't have to mess with allocation/deallocation then:

std::vector<char> bytes(myString.begin(), myString.end());
bytes.push_back('\0');
char *c = &bytes[0];

How do I convert a pandas Series or index to a Numpy array?

pandas >= 0.24

Deprecate your usage of .values in favour of these methods!

From v0.24.0 onwards, we will have two brand spanking new, preferred methods for obtaining NumPy arrays from Index, Series, and DataFrame objects: they are to_numpy(), and .array. Regarding usage, the docs mention:

We haven’t removed or deprecated Series.values or DataFrame.values, but we highly recommend and using .array or .to_numpy() instead.

See this section of the v0.24.0 release notes for more information.


to_numpy() Method

df.index.to_numpy()
# array(['a', 'b'], dtype=object)

df['A'].to_numpy()
#  array([1, 4])

By default, a view is returned. Any modifications made will affect the original.

v = df.index.to_numpy()
v[0] = -1

df
    A  B
-1  1  2
b   4  5

If you need a copy instead, use to_numpy(copy=True);

v = df.index.to_numpy(copy=True)
v[-1] = -123

df
   A  B
a  1  2
b  4  5

Note that this function also works for DataFrames (while .array does not).


array Attribute
This attribute returns an ExtensionArray object that backs the Index/Series.

pd.__version__
# '0.24.0rc1'

# Setup.
df = pd.DataFrame([[1, 2], [4, 5]], columns=['A', 'B'], index=['a', 'b'])
df

   A  B
a  1  2
b  4  5

df.index.array    
# <PandasArray>
# ['a', 'b']
# Length: 2, dtype: object

df['A'].array
# <PandasArray>
# [1, 4]
# Length: 2, dtype: int64

From here, it is possible to get a list using list:

list(df.index.array)
# ['a', 'b']

list(df['A'].array)
# [1, 4]

or, just directly call .tolist():

df.index.tolist()
# ['a', 'b']

df['A'].tolist()
# [1, 4]

Regarding what is returned, the docs mention,

For Series and Indexes backed by normal NumPy arrays, Series.array will return a new arrays.PandasArray, which is a thin (no-copy) wrapper around a numpy.ndarray. arrays.PandasArray isn’t especially useful on its own, but it does provide the same interface as any extension array defined in pandas or by a third-party library.

So, to summarise, .array will return either

  1. The existing ExtensionArray backing the Index/Series, or
  2. If there is a NumPy array backing the series, a new ExtensionArray object is created as a thin wrapper over the underlying array.

Rationale for adding TWO new methods
These functions were added as a result of discussions under two GitHub issues GH19954 and GH23623.

Specifically, the docs mention the rationale:

[...] with .values it was unclear whether the returned value would be the actual array, some transformation of it, or one of pandas custom arrays (like Categorical). For example, with PeriodIndex, .values generates a new ndarray of period objects each time. [...]

These two functions aim to improve the consistency of the API, which is a major step in the right direction.

Lastly, .values will not be deprecated in the current version, but I expect this may happen at some point in the future, so I would urge users to migrate towards the newer API, as soon as you can.

What is the purpose of wrapping whole Javascript files in anonymous functions like “(function(){ … })()”?

You can use function closures as data in larger expressions as well, as in this method of determining browser support for some of the html5 objects.

   navigator.html5={
     canvas: (function(){
      var dc= document.createElement('canvas');
      if(!dc.getContext) return 0;
      var c= dc.getContext('2d');
      return typeof c.fillText== 'function'? 2: 1;
     })(),
     localStorage: (function(){
      return !!window.localStorage;
     })(),
     webworkers: (function(){
      return !!window.Worker;
     })(),
     offline: (function(){
      return !!window.applicationCache;
     })()
    }

How to change the version of the 'default gradle wrapper' in IntelliJ IDEA?

The easiest way is to execute the following command from the command line (see Upgrading the Gradle Wrapper in documentation):

./gradlew wrapper --gradle-version 5.5

Moreover, you can use --distribution-type parameter with either bin or all value to choose a distribution type. Use all distribution type to avoid a hint from IntelliJ IDEA or Android Studio that will offer you to download Gradle with sources:

./gradlew wrapper --gradle-version 5.5 --distribution-type all

Or you can create a custom wrapper task

task wrapper(type: Wrapper) {
    gradleVersion = '5.5'
}

and run ./gradlew wrapper.

How to Read and Write from the Serial Port

SerialPort (RS-232 Serial COM Port) in C# .NET
This article explains how to use the SerialPort class in .NET to read and write data, determine what serial ports are available on your machine, and how to send files. It even covers the pin assignments on the port itself.

Example Code:

using System;
using System.IO.Ports;
using System.Windows.Forms;

namespace SerialPortExample
{
  class SerialPortProgram
  {
    // Create the serial port with basic settings
    private SerialPort port = new SerialPort("COM1",
      9600, Parity.None, 8, StopBits.One);

    [STAThread]
    static void Main(string[] args)
    { 
      // Instatiate this class
      new SerialPortProgram();
    }

    private SerialPortProgram()
    {
      Console.WriteLine("Incoming Data:");

      // Attach a method to be called when there
      // is data waiting in the port's buffer
      port.DataReceived += new 
        SerialDataReceivedEventHandler(port_DataReceived);

      // Begin communications
      port.Open();

      // Enter an application loop to keep this thread alive
      Application.Run();
    }

    private void port_DataReceived(object sender,
      SerialDataReceivedEventArgs e)
    {
      // Show all the incoming data in the port's buffer
      Console.WriteLine(port.ReadExisting());
    }
  }
}

AngularJS : Prevent error $digest already in progress when calling $scope.$apply()

I have been using this method and it seems to work perfectly fine. This just waits for the time the cycle has finished and then triggers apply(). Simply call the function apply(<your scope>) from anywhere you want.

function apply(scope) {
  if (!scope.$$phase && !scope.$root.$$phase) {
    scope.$apply();
    console.log("Scope Apply Done !!");
  } 
  else {
    console.log("Scheduling Apply after 200ms digest cycle already in progress");
    setTimeout(function() {
        apply(scope)
    }, 200);
  }
}

How to get all options of a select using jQuery?

For multiselect option:

$('#test').val() returns list of selected values. $('#test option').length returns total number of options (both selected and not selected)

How to use pip with python 3.4 on windows?

From the same page

Note: To avoid conflicts between parallel Python 2 and Python 3 installations, only the versioned pip3 and pip3.4 commands are bootstrapped by default when ensurepip is invoked directly - the --default-pip option is needed to also request the unversioned pip command. pyvenv and the Windows installer ensure that the unqualified pip command is made available in those environments, and pip can always be invoked via the -m switch rather than directly to avoid ambiguity on systems with multiple Python installations.

So try pip3 or pip3.4 in Command Prompt.

Also, ensure that environment variable are set for pip command, if you missed to opt-in for automatic PATH configuration.

How to iterate over the files of a certain directory, in Java?

Use java.io.File.listFiles
Or
If you want to filter the list prior to iteration (or any more complicated use case), use apache-commons FileUtils. FileUtils.listFiles

Cannot implicitly convert type 'int' to 'short'

The line

 Int16 answer = firstNo + secondNo;

is interpreted as

 Int16 answer = (Int32) (firstNo + secondNo);

Simply because there is no such thing as Int16 arithmetic.

The simple solution: Do not use Int16. Use Int32 or simply int.

int is your default integer type. short and long are only used in special cases.

How to submit a form when the return key is pressed?

Use the <button> tag. From the W3C standard:

Buttons created with the BUTTON element function just like buttons created with the INPUT element, but they offer richer rendering possibilities: the BUTTON element may have content. For example, a BUTTON element that contains an image functions like and may resemble an INPUT element whose type is set to "image", but the BUTTON element type allows content.

Basically there is another tag, <button>, which requires no javascript, that also can submit a form. It can be styled much in the way of a <div> tag (including <img /> inside the button tag). The buttons from the <input /> tag are not nearly as flexible.

<button type="submit">
    <img src="my-icon.png" />
    Clicking will submit the form
</button>

There are three types to set on the <button>; they map to the <input> button types.

<button type="submit">Will submit the form</button>
<button type="reset">Will reset the form</button>
<button type="button">Will do nothing; add javascript onclick hooks</button>

Standards

I use <button> tags with and a bit of styling to get colorful and functional form buttons. Note that it's possible to write css for, for example, <a class="button"> links share to styling with the <button> element.

Allowing Java to use an untrusted certificate for SSL/HTTPS connection

Following code from here is a useful solution. No keystores etc. Just call method SSLUtilities.trustAllHttpsCertificates() before initializing the service and port (in SOAP).

import java.security.GeneralSecurityException;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;
import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

/**
 * This class provide various static methods that relax X509 certificate and
 * hostname verification while using the SSL over the HTTP protocol.
 *  
 * @author Jiramot.info
 */
public final class SSLUtilities {

  /**
   * Hostname verifier for the Sun's deprecated API.
   *
   * @deprecated see {@link #_hostnameVerifier}.
   */
  private static com.sun.net.ssl.HostnameVerifier __hostnameVerifier;
  /**
   * Thrust managers for the Sun's deprecated API.
   *
   * @deprecated see {@link #_trustManagers}.
   */
  private static com.sun.net.ssl.TrustManager[] __trustManagers;
  /**
   * Hostname verifier.
   */
  private static HostnameVerifier _hostnameVerifier;
  /**
   * Thrust managers.
   */
  private static TrustManager[] _trustManagers;

  /**
   * Set the default Hostname Verifier to an instance of a fake class that
   * trust all hostnames. This method uses the old deprecated API from the
   * com.sun.ssl package.
   *  
   * @deprecated see {@link #_trustAllHostnames()}.
   */
  private static void __trustAllHostnames() {
    // Create a trust manager that does not validate certificate chains
    if (__hostnameVerifier == null) {
        __hostnameVerifier = new SSLUtilities._FakeHostnameVerifier();
    } // if
    // Install the all-trusting host name verifier
    com.sun.net.ssl.HttpsURLConnection
            .setDefaultHostnameVerifier(__hostnameVerifier);
  } // __trustAllHttpsCertificates

  /**
   * Set the default X509 Trust Manager to an instance of a fake class that
   * trust all certificates, even the self-signed ones. This method uses the
   * old deprecated API from the com.sun.ssl package.
   *
   * @deprecated see {@link #_trustAllHttpsCertificates()}.
   */
  private static void __trustAllHttpsCertificates() {
    com.sun.net.ssl.SSLContext context;

    // Create a trust manager that does not validate certificate chains
    if (__trustManagers == null) {
        __trustManagers = new com.sun.net.ssl.TrustManager[]{new SSLUtilities._FakeX509TrustManager()};
    } // if
    // Install the all-trusting trust manager
    try {
        context = com.sun.net.ssl.SSLContext.getInstance("SSL");
        context.init(null, __trustManagers, new SecureRandom());
    } catch (GeneralSecurityException gse) {
        throw new IllegalStateException(gse.getMessage());
    } // catch
    com.sun.net.ssl.HttpsURLConnection.setDefaultSSLSocketFactory(context
            .getSocketFactory());
  } // __trustAllHttpsCertificates

  /**
   * Return true if the protocol handler property java. protocol.handler.pkgs
   * is set to the Sun's com.sun.net.ssl. internal.www.protocol deprecated
   * one, false otherwise.
   *
   * @return true if the protocol handler property is set to the Sun's
   * deprecated one, false otherwise.
   */
  private static boolean isDeprecatedSSLProtocol() {
    return ("com.sun.net.ssl.internal.www.protocol".equals(System
            .getProperty("java.protocol.handler.pkgs")));
  } // isDeprecatedSSLProtocol

  /**
   * Set the default Hostname Verifier to an instance of a fake class that
   * trust all hostnames.
   */
  private static void _trustAllHostnames() {
      // Create a trust manager that does not validate certificate chains
      if (_hostnameVerifier == null) {
          _hostnameVerifier = new SSLUtilities.FakeHostnameVerifier();
      } // if
      // Install the all-trusting host name verifier:
      HttpsURLConnection.setDefaultHostnameVerifier(_hostnameVerifier);
  } // _trustAllHttpsCertificates

  /**
   * Set the default X509 Trust Manager to an instance of a fake class that
   * trust all certificates, even the self-signed ones.
   */
  private static void _trustAllHttpsCertificates() {
    SSLContext context;

      // Create a trust manager that does not validate certificate chains
      if (_trustManagers == null) {
          _trustManagers = new TrustManager[]{new SSLUtilities.FakeX509TrustManager()};
      } // if
      // Install the all-trusting trust manager:
      try {
          context = SSLContext.getInstance("SSL");
          context.init(null, _trustManagers, new SecureRandom());
      } catch (GeneralSecurityException gse) {
          throw new IllegalStateException(gse.getMessage());
      } // catch
      HttpsURLConnection.setDefaultSSLSocketFactory(context
            .getSocketFactory());
  } // _trustAllHttpsCertificates

  /**
   * Set the default Hostname Verifier to an instance of a fake class that
   * trust all hostnames.
   */
  public static void trustAllHostnames() {
      // Is the deprecated protocol setted?
      if (isDeprecatedSSLProtocol()) {
          __trustAllHostnames();
      } else {
          _trustAllHostnames();
      } // else
  } // trustAllHostnames

  /**
   * Set the default X509 Trust Manager to an instance of a fake class that
   * trust all certificates, even the self-signed ones.
   */
  public static void trustAllHttpsCertificates() {
    // Is the deprecated protocol setted?
    if (isDeprecatedSSLProtocol()) {
        __trustAllHttpsCertificates();
    } else {
        _trustAllHttpsCertificates();
    } // else
  } // trustAllHttpsCertificates

  /**
   * This class implements a fake hostname verificator, trusting any host
   * name. This class uses the old deprecated API from the com.sun. ssl
   * package.
   *
   * @author Jiramot.info
   *
   * @deprecated see {@link SSLUtilities.FakeHostnameVerifier}.
   */
  public static class _FakeHostnameVerifier implements
        com.sun.net.ssl.HostnameVerifier {

    /**
     * Always return true, indicating that the host name is an acceptable
     * match with the server's authentication scheme.
     *
     * @param hostname the host name.
     * @param session the SSL session used on the connection to host.
     * @return the true boolean value indicating the host name is trusted.
     */
    public boolean verify(String hostname, String session) {
        return (true);
    } // verify
  } // _FakeHostnameVerifier

  /**
   * This class allow any X509 certificates to be used to authenticate the
   * remote side of a secure socket, including self-signed certificates. This
   * class uses the old deprecated API from the com.sun.ssl package.
   *
   * @author Jiramot.info
   *
   * @deprecated see {@link SSLUtilities.FakeX509TrustManager}.
   */
  public static class _FakeX509TrustManager implements
        com.sun.net.ssl.X509TrustManager {

    /**
     * Empty array of certificate authority certificates.
     */
    private static final X509Certificate[] _AcceptedIssuers = new X509Certificate[]{};

    /**
     * Always return true, trusting for client SSL chain peer certificate
     * chain.
     *
     * @param chain the peer certificate chain.
     * @return the true boolean value indicating the chain is trusted.
     */
    public boolean isClientTrusted(X509Certificate[] chain) {
        return (true);
    } // checkClientTrusted

    /**
     * Always return true, trusting for server SSL chain peer certificate
     * chain.
     *
     * @param chain the peer certificate chain.
     * @return the true boolean value indicating the chain is trusted.
     */
    public boolean isServerTrusted(X509Certificate[] chain) {
        return (true);
    } // checkServerTrusted

    /**
     * Return an empty array of certificate authority certificates which are
     * trusted for authenticating peers.
     *
     * @return a empty array of issuer certificates.
     */
    public X509Certificate[] getAcceptedIssuers() {
        return (_AcceptedIssuers);
    } // getAcceptedIssuers
  } // _FakeX509TrustManager

  /**
   * This class implements a fake hostname verificator, trusting any host
   * name.
   *
   * @author Jiramot.info
   */
  public static class FakeHostnameVerifier implements HostnameVerifier {

    /**
     * Always return true, indicating that the host name is an acceptable
     * match with the server's authentication scheme.
     *
     * @param hostname the host name.
     * @param session the SSL session used on the connection to host.
     * @return the true boolean value indicating the host name is trusted.
     */
    public boolean verify(String hostname, javax.net.ssl.SSLSession session) {
        return (true);
    } // verify
  } // FakeHostnameVerifier

  /**
   * This class allow any X509 certificates to be used to authenticate the
   * remote side of a secure socket, including self-signed certificates.
   *
   * @author Jiramot.info
   */
  public static class FakeX509TrustManager implements X509TrustManager {

    /**
     * Empty array of certificate authority certificates.
     */
    private static final X509Certificate[] _AcceptedIssuers = new X509Certificate[]{};

    /**
     * Always trust for client SSL chain peer certificate chain with any
     * authType authentication types.
     *
     * @param chain the peer certificate chain.
     * @param authType the authentication type based on the client
     * certificate.
     */
    public void checkClientTrusted(X509Certificate[] chain, String authType) {
    } // checkClientTrusted

    /**
     * Always trust for server SSL chain peer certificate chain with any
     * authType exchange algorithm types.
     *
     * @param chain the peer certificate chain.
     * @param authType the key exchange algorithm used.
     */
    public void checkServerTrusted(X509Certificate[] chain, String authType) {
    } // checkServerTrusted

    /**
     * Return an empty array of certificate authority certificates which are
     * trusted for authenticating peers.
     *
     * @return a empty array of issuer certificates.
     */
    public X509Certificate[] getAcceptedIssuers() {
        return (_AcceptedIssuers);
    } // getAcceptedIssuers
  } // FakeX509TrustManager
} // SSLUtilities

Change PictureBox's image to image from my resources?

You must specify the full path of the resource file as the name of 'image within the resources of your application, see example below.

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    PictureBox1.Image = My.Resources.Chrysanthemum
End Sub

In the path assigned to the Image property after MyResources specify the name of the resource.

But before you do whatever you have to import in the resource section of your application from an image file exists or it can create your own.

Bye

How to increase size of DOSBox window?

  • go to dosbox installation directory (on my machine that is C:\Program Files (x86)\DOSBox-0.74 ) as you see the version number is part of the installation directory name.

  • run "DOSBox 0.74 Options.bat"

  • the script starts notepad with configuration file: here change

    windowresolution=1600x800

    output=ddraw

(the resolution can't be changed if output=surface - that's the default).

  • safe configuration file changes.

All shards failed

If you encounter this apparent index corruption in a running system, you can work around it by deleting all files called segments.gen. It is advisory only, and Lucene can recover correctly without it.

From ElasticSearch Blog

Eclipse Intellisense?

Tony is a pure genius. However to achieve even better auto-completion try setting the triggers to this:

ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz =.(!+-*/~,[{@#$%^&

(specifically aranged in order of usage for faster performance :)

jQuery validation: change default error message

The newest version has some nice in-line stuff you can do.

If it's a simple input field you can add the attribute data-validation-error-msg like this --

data-validation-error-msg="Invalid Regex"

If you need something a little heavier you can fully customize things using a variable with all the values which is passed into the validate function. Reference this link for full details -- https://github.com/victorjonsson/jQuery-Form-Validator#fully-customizable

How to search JSON tree with jQuery

Once you have the JSON loaded into a JavaScript object, it's no longer a jQuery problem but is now a JavaScript problem. In JavaScript you could for instance write a search such as:

var people = myJson["people"];
var persons = people["person"];
for(var i=0; i < persons.length; ++i) {
    var person_i = persons[i];
    if(person_i["name"] == mySearchForName) {
        // found ! do something with 'person_i'.
        break;
    }
}
// not found !

How to check if an array value exists?

Just use the PHP function array_key_exists()

<?php
$search_array = array('first' => 1, 'second' => 4);
if (array_key_exists('first', $search_array)) {
    echo "The 'first' element is in the array";
}
?>

How to Maximize window in chrome using webDriver (python)

Nothing worked for me except:

driver.set_window_size(1024, 600)
driver.maximize_window()

I found this by inspecting selenium/webdriver/remote/webdriver.py. I've never found any useful documentation, but reading the code has been marginally effective.

Can you style html form buttons with css?

You might want to add:

-webkit-appearance: none; 

if you need it looking consistent on Mobile Safari...

Language Books/Tutorials for popular languages

Given recent developments I think it's important to include the recent explosion of free online course offerings from universities and private companies. The new boston is a tutorial site i've always used for numerous languages for years, great beginner point.

http://www.udacity.com/

https://www.coursera.org/

http://www.coursehero.org/

http://www.codecademy.com/

http://mitx.mit.edu/

http://www.khanacademy.org/

http://thenewboston.org/

What's is the difference between train, validation and test set, in neural networks?

Training Dataset: The sample of data used to fit the model.

Validation Dataset: The sample of data used to provide an unbiased evaluation of a model fit on the training dataset while tuning model hyperparameters. The evaluation becomes more biased as skill on the validation dataset is incorporated into the model configuration.

Test Dataset: The sample of data used to provide an unbiased evaluation of a final model fit on the training dataset.

MySQL Where DateTime is greater than today

Remove the date() part

SELECT name, datum 
FROM tasks 
WHERE datum >= NOW()

and if you use a specific date, don't forget the quotes around it and use the proper format with :

SELECT name, datum 
FROM tasks 
WHERE datum >= '2014-05-18 15:00:00'

How to insert special characters into a database?

htmlspecialchars function is the best solution fellows. Today I was searching for how to insert strings with special characters and the google thrown so many Stackoverflow listings.None of them provided me solution. I found it in w3schools page. Yes I could solve my problem by using this function like this:

$abc = $POST['xyz'];

$abc = htmlspecialchars($abc);

android fragment- How to save states of views in a fragment when another fragment is pushed on top of it

I used a hybrid approach for fragments containing a list view. It seems to be performant since I don't replace the current fragment but rather add the new fragment and hide the current one. I have the following method in the activity that hosts my fragments:

public void addFragment(Fragment currentFragment, Fragment targetFragment, String tag) {
    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction transaction = fragmentManager.beginTransaction();
    transaction.setCustomAnimations(0,0,0,0);
    transaction.hide(currentFragment);
    // use a fragment tag, so that later on we can find the currently displayed fragment
    transaction.add(R.id.frame_layout, targetFragment, tag)
            .addToBackStack(tag)
            .commit();
}

I use this method in my fragment (containing the list view) whenever a list item is clicked/tapped (and thus I need to launch/display the details fragment):

FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
SearchFragment currentFragment = (SearchFragment) fragmentManager.findFragmentByTag(getFragmentTags()[0]);
DetailsFragment detailsFragment = DetailsFragment.newInstance("some object containing some details");
((MainActivity) getActivity()).addFragment(currentFragment, detailsFragment, "Details");

getFragmentTags() returns an array of strings that I use as tags for different fragments when I add a new fragment (see transaction.add method in addFragment method above).

In the fragment containing the list view, I do this in its onPause() method:

@Override
public void onPause() {
    // keep the list view's state in memory ("save" it) 
    // before adding a new fragment or replacing current fragment with a new one
    ListView lv =  (ListView) getActivity().findViewById(R.id.listView);
    mListViewState = lv.onSaveInstanceState();
    super.onPause();
}

Then in onCreateView of the fragment (actually in a method that is invoked in onCreateView), I restore the state:

// Restore previous state (including selected item index and scroll position)
if(mListViewState != null) {
    Log.d(TAG, "Restoring the listview's state.");
    lv.onRestoreInstanceState(mListViewState);
}

Assigning default value while creating migration file

Default migration generator does not handle default values (column modifiers are supported but do not include default or null), but you could create your own generator.

You can also manually update the migration file prior to running rake db:migrate by adding the options to add_column:

add_column :tweet, :retweets_count, :integer, :null => false, :default => 0

... and read Rails API

How to resolve the error on 'react-native start'

On windows 10 i highly recommend to install Linux Bash Shell.

Here is a nice guide to set it up: https://www.howtogeek.com/249966/how-to-install-and-use-the-linux-bash-shell-on-windows-10/

just follow the steps, choose your linux distribution and avoid as much possible to work with node on cmd since obvious instability.

Take in consideration Microsoft strongly warns against adding or modifying Linux files with Windows software, as described here: howtogeek.com/261383/how-to-access-your-ubuntu-bash-files-in-windows-and-your-windows-system-drive-in-bash/

Hope it helps!

How to pass parameter to click event in Jquery

You don't need to pass the parameter, you can get it using .attr() method

$(function(){
    $('elements-to-match').click(function(){
        alert("The id is "+ $(this).attr("id") );
    });
});

get user timezone

Just as Oded has answered. You need to have this sort of detection functionality in javascript.

I've struggled with this myself and realized that the offset is not enough. It does not give you any information about daylight saving for example. I ended up writing some code to map to zoneinfo database keys.

By checking several dates around a year you can more accurately determine a timezone.

Try the script here: http://jsfiddle.net/pellepim/CsNcf/

Simply change your system timezone and click run to test it. If you are running chrome you need to do each test in a new tab though (and safar needs to be restarted to pick up timezone changes).

If you want more details of the code check out: https://bitbucket.org/pellepim/jstimezonedetect/

Counting number of occurrences in column?

A simpler approach to this

At the beginning of column B, type

=UNIQUE(A:A)

Then in column C, use

=COUNTIF(A:A, B1)

and copy them in all row column C.

Edit: If that doesn't work for you, try using semicolon instead of comma:

=COUNTIF(A:A; B1)

BarCode Image Generator in Java

ZXing is a free open source Java library to read and generate barcode images. You need to get the source code and build the jars yourself. Here's a simple tutorial that I wrote for building with ZXing jars and writing your first program with ZXing.

[http://www.vineetmanohar.com/2010/09/java-barcode-api/]

SQL Server Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >=

SELECT COLUMN 
    FROM TABLE 
WHERE columns_name
    IN ( SELECT COLUMN FROM TABLE WHERE columns_name = 'value');

note: when we are using sub-query we must focus on these points:

  1. if our sub query returns 1 value in this case we need to use (=,!=,<>,<,>....)
  2. else (more than one value), in this case we need to use (in, any, all, some )

How can I debug my JavaScript code?

I found the new version of Internet Explorer 8 (press F12) is very good to debug JavaScript code.

Of course, Firebug is good if you use Firefox.

How to grep, excluding some patterns?

A bit old, but oh well...

The most up-voted solution from @houbysoft will not work as that will exclude any line with "gloom" in it, even if it has "loom". According to OP's expectations, we need to include lines with "loom", even if they also have "gloom" in them. This line needs to be in the output "Arty is slooming in a gloomy day.", but this will be excluded by a chained grep like

grep -n 'loom' ~/projects/**/trunk/src/**/*.@(h|cpp) | grep -v 'gloom'

Instead, the egrep regex example of Bentoy13 works better

egrep '(^|[^g])loom' ~/projects/**/trunk/src/**/*.@(h|cpp)

as it will include any line with "loom" in it, regardless of whether or not it has "gloom". On the other hand, if it only has gloom, it will not include it, which is precisely the behaviour OP wants.

Convert an enum to List<string>

Use Enum's static method, GetNames. It returns a string[], like so:

Enum.GetNames(typeof(DataSourceTypes))

If you want to create a method that does only this for only one type of enum, and also converts that array to a List, you can write something like this:

public List<string> GetDataSourceTypes()
{
    return Enum.GetNames(typeof(DataSourceTypes)).ToList();
}

You will need Using System.Linq; at the top of your class to use .ToList()