Programs & Examples On #Mappath

How to set up a Web API controller for multipart/form-data

Here's another answer for the ASP.Net Core solution to this problem...

On the Angular side, I took this code example...

https://stackblitz.com/edit/angular-drag-n-drop-directive

... and modified it to call an HTTP Post endpoint:

  prepareFilesList(files: Array<any>) {

    const formData = new FormData();
    for (var i = 0; i < files.length; i++) { 
      formData.append("file[]", files[i]);
    }

    let URL = "https://localhost:44353/api/Users";
    this.http.post(URL, formData).subscribe(
      data => { console.log(data); },
      error => { console.log(error); }
    );

With this in place, here's the code I needed in the ASP.Net Core WebAPI controller:

[HttpPost]
public ActionResult Post()
{
  try
  {
    var files = Request.Form.Files;

    foreach (IFormFile file in files)
    {
        if (file.Length == 0)
            continue;
        
        string tempFilename = Path.Combine(Path.GetTempPath(), file.FileName);
        System.Diagnostics.Trace.WriteLine($"Saved file to: {tempFilename}");

        using (var fileStream = new FileStream(tempFilename, FileMode.Create))
        {
            file.CopyTo(fileStream);
        }
    }
    return new OkObjectResult("Yes");
  }
  catch (Exception ex)
  {
    return new BadRequestObjectResult(ex.Message);
  }
}

Shockingly simple, but I had to piece together examples from several (almost-correct) sources to get this to work properly.

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.

How do I to insert data into an SQL table using C# as well as implement an upload function?

using System;
using System.Data;
using System.Data.SqlClient;

namespace InsertingData
{
    class sqlinsertdata
    {
        static void Main(string[] args)
        {
            try
            { 
            SqlConnection conn = new SqlConnection("Data source=USER-PC; Database=Emp123;User Id=sa;Password=sa123");
            conn.Open();
                SqlCommand cmd = new SqlCommand("insert into <Table Name>values(1,'nagendra',10000);",conn);
                cmd.ExecuteNonQuery();
                Console.WriteLine("Inserting Data Successfully");
                conn.Close();
        }
            catch(Exception e)
            {
                Console.WriteLine("Exception Occre while creating table:" + e.Message + "\t"  + e.GetType());
            }
            Console.ReadKey();

    }
    }
}

Could not load file or assembly 'Newtonsoft.Json' or one of its dependencies. Manifest definition does not match the assembly reference

Easy steps. (1)Run "update-package Newtonsoft.Json -reinstall" in package manager.

(2)Delete you bin by enabling viewing the hidden files and deleting the bin folder.

(3)Close your visual studio and re-open it.

(4) Now run your project again. I believe it should be ok

Getting Error 800a0e7a "Provider cannot be found. It may not be properly installed."

I got the same issue and It got solved by installing Oracle 11g client in my machine..

I have not installed any excclusive drivers for it. I am using windows7 with 64 bit. Interestignly, when I navigate into the path Start > Settings > Control Panel > Administrative Tools > DataSources(ODBC) > Drivers. I found only SQL server in it

Please Finc the attachment below for the same

Runtime error: Could not load file or assembly 'System.Web.WebPages.Razor, Version=3.0.0.0

I got this error because such DLL (and many others) were missing in bin folder when I pubished the web application. It seemed like a bug in Visual Studio publish function. Cleaning, recompiling and publishing it again, made such DLLs to be published correctly.

ASP.NET file download from server

Further to Karl Anderson solution, you could put your parameters into session information and then clear them after response.TransmitFile(Server.MapPath( Session(currentSessionItemName)));.

See MSDN page HttpSessionState.Add Method (String, Object) for more information on sessions.

Exception of type 'System.OutOfMemoryException' was thrown.

Running in Debug Mode

When you're developing and debugging an application, you will typically run with the debug attribute in the web.config file set to true and your DLLs compiled in debug mode. However, before you deploy your application to test or to production, you should compile your components in release mode and set the debug attribute to false.

ASP.NET works differently on many levels when running in debug mode. In fact, when you are running in debug mode, the GC will allow your objects to remain alive longer (until the end of the scope) so you will always see higher memory usage when running in debug mode.

Another often unrealized side-effect of running in debug mode is that client scripts served via the webresource.axd and scriptresource.axd handlers will not be cached. That means that each client request will have to download any scripts (such as ASP.NET AJAX scripts) instead of taking advantage of client-side caching. This can lead to a substantial performance hit.

Source: http://blogs.iis.net/webtopics/archive/2009/05/22/troubleshooting-system-outofmemoryexceptions-in-asp-net.aspx

Microsoft Web API: How do you do a Server.MapPath?

You can try like:

var path="~/Image/test.png"; System.Web.Hosting.HostingEnvironment.MapPath( @ + path)

MVC 4 Razor File Upload

View Page

@using (Html.BeginForm("ActionmethodName", "ControllerName", FormMethod.Post, new { id = "formid" }))
 { 
   <input type="file" name="file" />
   <input type="submit" value="Upload" class="save" id="btnid" />
 }

script file

$(document).on("click", "#btnid", function (event) {
        event.preventDefault();
        var fileOptions = {
            success: res,
            dataType: "json"
        }
        $("#formid").ajaxSubmit(fileOptions);
    });

In Controller

    [HttpPost]
    public ActionResult UploadFile(HttpPostedFileBase file)
    {

    }

Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib

In my case after downgrading from .NET 4.5 to .NET 4.0 project was working fine on a local machine, but was failing on server after publishing.

Turns out that destination had some old assemblies, which were still referencing .NET 4.5.

Fixed it by enabling publishing option "Delete all existing files prior to publish"

Could not load file or assembly 'Microsoft.Web.Infrastructure,

On my machine the Nuget dependency wasn't downloaded correctly, the lib folder inside the nuget package didn't exist, hence the error.

Before

enter image description here

I renamed the Nuget Package in the packages folder and Nuget redownloaded it correctly with the necessary lib folder.

After enter image description here

Error Microsoft.Web.Infrastructure, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35

I had the same problem and the "Microsoft.Web.Infrastructure.dll" appeared to be missing. I have tried few advises and installed MVC`s etc. and nothing helped. The solution was to install "Web Services Enhancements (WSE) 1.0 SP1 for Microsoft .NET" which includes Microsoft.Web.Infrastructure.dll. Available at: http://www.microsoft.com/en-gb/download/details.aspx?id=4065

The module was expected to contain an assembly manifest

BadImageFormatException, in my experience, is almost always to do with x86 versus x64 compiled assemblies. It sounds like your C++ assembly is compiled for x86 and you are running on an x64 process. Is that correct?

Instead of using AnyCPU/Mixed as the platform. Try to manually set it to x86 and see if it will run after that.

Hope this helps.

How to set downloading file name in ASP.NET Web API

If you want to ensure that the file name is properly encoded but also avoid the WebApi HttpResponseMessage you can use the following:

Response.AddHeader("Content-Disposition", new System.Net.Mime.ContentDisposition("attachment") { FileName = "foo.txt" }.ToString());

You may use either ContentDisposition or ContentDispositionHeaderValue. Calling ToString on an instance of either will do the encoding of file names for you.

Pass a simple string from controller to a view MVC3

Why not create a viewmodel with a simple string parameter and then pass that to the view? It has the benefit of being extensible (i.e. you can then add any other things you may want to set in your controller) and it's fairly simple.

public class MyViewModel
{
    public string YourString { get; set; }
}

In the view

@model MyViewModel
@Html.Label(model => model.YourString)

In the controller

public ActionResult Index() 
{
     myViewModel = new MyViewModel();
     myViewModel.YourString = "However you are setting this."
     return View(myViewModel)
}

Cannot use Server.MapPath

Try adding System.Web as a reference to your project.

Could not load file or assembly 'System.Web.WebPages.Razor, Version=2.0.0.0

After much pain, googling and hair pulling, I ended up uninstalling MVC 4 using nuget, deleting all references to MVC, razor and infrastructure from the web config, deleting the dlls from the bin folder - then using nuget to reinstall everything. It took less time then trying to figure out why the dlls did not match.

How to write "Html.BeginForm" in Razor

The following code works fine:

@using (Html.BeginForm("Upload", "Upload", FormMethod.Post, 
                                      new { enctype = "multipart/form-data" }))
{
    @Html.ValidationSummary(true)
    <fieldset>
        Select a file <input type="file" name="file" />
        <input type="submit" value="Upload" />
    </fieldset>
}

and generates as expected:

<form action="/Upload/Upload" enctype="multipart/form-data" method="post">    
    <fieldset>
        Select a file <input type="file" name="file" />
        <input type="submit" value="Upload" />
    </fieldset>
</form>

On the other hand if you are writing this code inside the context of other server side construct such as an if or foreach you should remove the @ before the using. For example:

@if (SomeCondition)
{
    using (Html.BeginForm("Upload", "Upload", FormMethod.Post, 
                                      new { enctype = "multipart/form-data" }))
    {
        @Html.ValidationSummary(true)
        <fieldset>
            Select a file <input type="file" name="file" />
            <input type="submit" value="Upload" />
        </fieldset>
    }
}

As far as your server side code is concerned, here's how to proceed:

[HttpPost]
public ActionResult Upload(HttpPostedFileBase file) 
{
    if (file != null && file.ContentLength > 0) 
    {
        var fileName = Path.GetFileName(file.FileName);
        var path = Path.Combine(Server.MapPath("~/content/pics"), fileName);
        file.SaveAs(path);
    }
    return RedirectToAction("Upload");
}

"The given path's format is not supported."

If the value is a file url like file://C:/whatever, use the Uri class to translate to a regular filename:

var localPath = (new Uri(urlStylePath)).AbsolutePath

In general, using the provided API is best practice.

Merging multiple PDFs using iTextSharp in c#.net

I found a very nice solution on this site : http://weblogs.sqlteam.com/mladenp/archive/2014/01/10/simple-merging-of-pdf-documents-with-itextsharp-5-4-5.aspx

I update the method in this mode :

    public static bool MergePDFs(IEnumerable<string> fileNames, string targetPdf)
    {
        bool merged = true;
        using (FileStream stream = new FileStream(targetPdf, FileMode.Create))
        {
            Document document = new Document();
            PdfCopy pdf = new PdfCopy(document, stream);
            PdfReader reader = null;
            try
            {
                document.Open();
                foreach (string file in fileNames)
                {
                    reader = new PdfReader(file);
                    pdf.AddDocument(reader);
                    reader.Close();
                }
            }
            catch (Exception)
            {
                merged = false;
                if (reader != null)
                {
                    reader.Close();
                }
            }
            finally
            {
                if (document != null)
                {
                    document.Close();
                }
            }
        }
        return merged;
    }

Data at the root level is invalid

This:

doc.LoadXml(HttpContext.Current.Server.MapPath("officeList.xml"));

should be:

doc.Load(HttpContext.Current.Server.MapPath("officeList.xml"));

LoadXml() is for loading an XML string, not a file name.

Download/Stream file from URL - asp.net

I do this quite a bit and thought I could add a simpler answer. I set it up as a simple class here, but I run this every evening to collect financial data on companies I'm following.

class WebPage
{
    public static string Get(string uri)
    {
        string results = "N/A";

        try
        {
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(uri);
            HttpWebResponse resp = (HttpWebResponse)req.GetResponse();

            StreamReader sr = new StreamReader(resp.GetResponseStream());
            results = sr.ReadToEnd();
            sr.Close();
        }
        catch (Exception ex)
        {
            results = ex.Message;
        }
        return results;
    }
}

In this case I pass in a url and it returns the page as HTML. If you want to do something different with the stream instead you can easily change this.

You use it like this:

string page = WebPage.Get("http://finance.yahoo.com/q?s=yhoo");

converting a base 64 string to an image and saving it

You can save Base64 directly into file:

string filePath = "MyImage.jpg";
File.WriteAllBytes(filePath, Convert.FromBase64String(base64imageString));

Server.MapPath - Physical path given, virtual path expected

if you already know your folder is: E:\ftproot\sales then you do not need to use Server.MapPath, this last one is needed if you only have a relative virtual path like ~/folder/folder1 and you want to know the real path in the disk...

XmlDocument - load from string?

XmlDocument doc = new XmlDocument();
doc.LoadXml(str);

Where str is your XML string. See the MSDN article for more info.

MVC 3 file upload and model binding

Solved

Model

public class Book
{
public string Title {get;set;}
public string Author {get;set;}
}

Controller

public class BookController : Controller
{
     [HttpPost]
     public ActionResult Create(Book model, IEnumerable<HttpPostedFileBase> fileUpload)
     {
         throw new NotImplementedException();
     }
}

And View

@using (Html.BeginForm("Create", "Book", FormMethod.Post, new { enctype = "multipart/form-data" }))
{      
     @Html.EditorFor(m => m)

     <input type="file" name="fileUpload[0]" /><br />      
     <input type="file" name="fileUpload[1]" /><br />      
     <input type="file" name="fileUpload[2]" /><br />      

     <input type="submit" name="Submit" id="SubmitMultiply" value="Upload" />
}

Note title of parameter from controller action must match with name of input elements IEnumerable<HttpPostedFileBase> fileUpload -> name="fileUpload[0]"

fileUpload must match

Using Server.MapPath() inside a static field in ASP.NET MVC

Try HostingEnvironment.MapPath, which is static.

See this SO question for confirmation that HostingEnvironment.MapPath returns the same value as Server.MapPath: What is the difference between Server.MapPath and HostingEnvironment.MapPath?

"Invalid JSON primitive" in Ajax processing

these answers just had me bouncing back and forth between invalid parameter and missing parameter.

this worked for me , just wrap string variables in quotes...

data: { RecordId: RecordId,
            UserId: UId,
            UserProfileId: UserProfileId,
            ItemType: '"' +  ItemType + '"',
            FileName: '"' +  XmlName + '"'
    }

Java: How to check if object is null?

drawable.equals(null)

The above line calls the "equals(...)" method on the drawable object.

So, when drawable is not null and it is a real object, then all goes well as calling the "equals(null)" method will return "false"

But when "drawable" is null, then it means calling the "equals(...)" method on null object, means calling a method on an object that doesn't exist so it throws "NullPointerException"

To check whether an object exists and it is not null, use the following

if(drawable == null) {
    ...
    ...
}

In above condition, we are checking that the reference variable "drawable" is null or contains some value (reference to its object) so it won't throw exception in case drawable is null as checking

null == null

is valid.

Could not load file or assembly 'System.Data.SQLite'

I came up with 2 quick solutions. Either work for me. I think the problem is because of permissions.

1) Instead of using the Elmah.dll file from the net-2.0 directory, I used Elmah.dll from net-1.1 .

2) Instead of keeping Elmah.dll in the project bin directory. I make a dll directory to put it in.

How to call a Web Service Method?

The current way to do this is by using the "Add Service Reference" command. If you specify "TestUploaderWebService" as the service reference name, that will generate the type TestUploaderWebService.Service1. That class will have a method named GetFileListOnWebServer, which will return an array of strings (you can change that to be a list of strings if you like). You would use it like this:

string[] files = null;
TestUploaderWebService.Service1 proxy = null;
bool success = false;
try
{
    proxy = new TestUploaderWebService.Service1();
    files = proxy.GetFileListOnWebServer();
    proxy.Close();
    success = true;
}
finally
{
    if (!success)
    {
        proxy.Abort();
    }
}

P.S. Tell your instructor to look at "Microsoft: ASMX Web Services are a “Legacy Technology”", and ask why he's teaching out of date technology.

Server.Mappath in C# classlibrary

Maybe you could abstract this as a dependency and create an IVirtualPathResolver. This way your service classes wouldn't be bound to System.Web and you could create another implementation if you wanted to reuse your logic in a different UI technology.

Using Server.MapPath in external C# Classes in ASP.NET

System.Reflection.Assembly.GetAssembly(type).Location

IF the file you are trying to get is the assembly location for a type. But if the files are relative to the assembly location then you can use this with System.IO namespace to get the exact path of the file.

How to Deserialize XML document

Try this Generic Class For Xml Serialization & Deserialization.

public class SerializeConfig<T> where T : class
{
    public static void Serialize(string path, T type)
    {
        var serializer = new XmlSerializer(type.GetType());
        using (var writer = new FileStream(path, FileMode.Create))
        {
            serializer.Serialize(writer, type);
        }
    }

    public static T DeSerialize(string path)
    {
        T type;
        var serializer = new XmlSerializer(typeof(T));
        using (var reader = XmlReader.Create(path))
        {
            type = serializer.Deserialize(reader) as T;
        }
        return type;
    }
}

Server.MapPath("."), Server.MapPath("~"), Server.MapPath(@"\"), Server.MapPath("/"). What is the difference?

Server.MapPath specifies the relative or virtual path to map to a physical directory.

  • Server.MapPath(".")1 returns the current physical directory of the file (e.g. aspx) being executed
  • Server.MapPath("..") returns the parent directory
  • Server.MapPath("~") returns the physical path to the root of the application
  • Server.MapPath("/") returns the physical path to the root of the domain name (is not necessarily the same as the root of the application)

An example:

Let's say you pointed a web site application (http://www.example.com/) to

C:\Inetpub\wwwroot

and installed your shop application (sub web as virtual directory in IIS, marked as application) in

D:\WebApps\shop

For example, if you call Server.MapPath() in following request:

http://www.example.com/shop/products/GetProduct.aspx?id=2342

then:

  • Server.MapPath(".")1 returns D:\WebApps\shop\products
  • Server.MapPath("..") returns D:\WebApps\shop
  • Server.MapPath("~") returns D:\WebApps\shop
  • Server.MapPath("/") returns C:\Inetpub\wwwroot
  • Server.MapPath("/shop") returns D:\WebApps\shop

If Path starts with either a forward slash (/) or backward slash (\), the MapPath() returns a path as if Path was a full, virtual path.

If Path doesn't start with a slash, the MapPath() returns a path relative to the directory of the request being processed.

Note: in C#, @ is the verbatim literal string operator meaning that the string should be used "as is" and not be processed for escape sequences.

Footnotes

  1. Server.MapPath(null) and Server.MapPath("") will produce this effect too.

Move an array element from one array position to another

I ended up combining two of these to work a little better when moving both small and large distances. I get fairly consistent results, but this could probably be tweaked a little bit by someone smarter than me to work differently for different sizes, etc.

Using some of the other methods when moving objects small distances was significantly faster (x10) than using splice. This might change depending on the array lengths though, but it is true for large arrays.

function ArrayMove(array, from, to) {
    if ( Math.abs(from - to) > 60) {
        array.splice(to, 0, array.splice(from, 1)[0]);
    } else {
        // works better when we are not moving things very far
        var target = array[from];
        var inc = (to - from) / Math.abs(to - from);
        var current = from;
        for (; current != to; current += inc) {
            array[current] = array[current + inc];
        }
        array[to] = target;    
    }
}

http://jsperf.com/arraymove-many-sizes

NPM clean modules

I added this to my package.json:

"build": "npm build",
"clean": "rm -rf node_modules", 
"reinstall": "npm run clean && npm install", 
"rebuild": "npm run clean && npm install && npm run build",

Seems to work well.

How to change port number for apache in WAMP

Change port number for Xampp Go to the file C:\xampp\apache\conf\httpd.conf

#Listen 12.34.56.78:80
Listen 80

Change 80 to 82

as

#Listen 12.34.56.78:82
Listen 82

now your url will be

http://localhost:82

How to concatenate strings in django templates?

I found working with the {% with %} tag to be quite a hassle. Instead I created the following template tag, which should work on strings and integers.

from django import template

register = template.Library()


@register.filter
def concat_string(value_1, value_2):
    return str(value_1) + str(value_2)

Then load the template tag in your template at the top using the following:

{% load concat_string %}

You can then use it the following way:

<a href="{{ SOME_DETAIL_URL|concat_string:object.pk }}" target="_blank">123</a>

I personally found this to be a lot cleaner to work with.

Checking whether a string starts with XXXX

RanRag has already answered it for your specific question.

However, more generally, what you are doing with

if [[ "$string" =~ ^hello ]]

is a regex match. To do the same in Python, you would do:

import re
if re.match(r'^hello', somestring):
    # do stuff

Obviously, in this case, somestring.startswith('hello') is better.

Correct way to detach from a container without stopping it

I consider Ashwin's answer to be the most correct, my old answer is below.


I'd like to add another option here which is to run the container as follows

docker run -dti foo bash

You can then enter the container and run bash with

docker exec -ti ID_of_foo bash

No need to install sshd :)

What's the C# equivalent to the With statement in VB?

The closest thing in C# 3.0, is that you can use a constructor to initialize properties:

Stuff.Elements.Foo foo = new Stuff.Elements.Foo() {Name = "Bob Dylan", Age = 68, Location = "On Tour", IsCool = true}

VBA Excel sort range by specific column

If the starting cell of the range and of the key is static, the solution can be very simple:

Range("A3").Select
Range(Selection, Selection.End(xlToRight)).Select
Range(Selection, Selection.End(xlDown)).Select
Selection.Sort key1:=Range("B3", Range("B3").End(xlDown)), _
order1:=xlAscending, Header:=xlNo

Convert comma separated string of ints to int array

I think is good enough. It's clear, it lazy so it will be fast (except maybe the first case when you split the string).

Multiplication on command line terminal

For more advanced and precise math consider using bc(1).

echo "3 * 2.19" | bc -l 
6.57

How to tell Maven to disregard SSL errors (and trusting all certs)?

Create a folder ${USER_HOME}/.mvn and put a file called maven.config in it.

The content should be:

-Dmaven.wagon.http.ssl.insecure=true
-Dmaven.wagon.http.ssl.allowall=true
-Dmaven.wagon.http.ssl.ignore.validity.dates=true

Hope this helps.

How can I check if a string contains ANY letters from the alphabet?

I liked the answer provided by @jean-françois-fabre, but it is incomplete.
His approach will work, but only if the text contains purely lower- or uppercase letters:

>>> text = "(555).555-5555 extA. 5555"
>>> text.islower()
False
>>> text.isupper()
False

The better approach is to first upper- or lowercase your string and then check.

>>> string1 = "(555).555-5555 extA. 5555"
>>> string2 = '555 (234) - 123.32   21'

>>> string1.upper().isupper()
True
>>> string2.upper().isupper()
False

Gradle Sync failed could not find constraint-layout:1.0.0-alpha2

Not sure if I'm too late, but in case someone has still the error after an update of ConstraintLayout and Solver over the SDK Tools, maybe this solution could help: Error:(30, 13) Failed to resolve: com.android.support.constraint:constraint-layout:1.0.0-alpha4

Routing HTTP Error 404.0 0x80070002

Uncheck this in Windows Explorer.

"Hide file type extensions for known types"

Why can't I push to this bare repository?

git push --all

is the canonical way to push everything to a new bare repository.

Another way to do the same thing is to create your new, non-bare repository and then make a bare clone with

git clone --bare

then use

git remote add origin <new-remote-repo>

in the original (non-bare) repository.

How to align matching values in two columns in Excel, and bring along associated values in other columns

Skip all of this. Download Microsoft FUZZY LOOKUP add in. Create tables using your columns. Create a new worksheet. INPUT tables into the tool. Click all corresponding columns check boxes. Use slider for exact matches. HIT go and wait for the magic.

What is the difference between <p> and <div>?

A p tag is for a paragraph, generally used for text. A div tag is for division, and generally used for creating sections of text.

How to get the containing form of an input?

And one more....

var _e = $(e.target); // e being the event triggered
var element = _e.parent(); // the element the event was triggered on
console.log("_E " + element.context); // [object HTMLInputElement]
console.log("_E FORM " + element.context.form); // [object HTMLFormElement]
console.log("_E FORM " + element.context.form.id); // form id

Understanding the ngRepeat 'track by' expression

a short summary:

track by is used in order to link your data with the DOM generation (and mainly re-generation) made by ng-repeat.

when you add track by you basically tell angular to generate a single DOM element per data object in the given collection

this could be useful when paging and filtering, or any case where objects are added or removed from ng-repeat list.

usually, without track by angular will link the DOM objects with the collection by injecting an expando property - $$hashKey - into your JavaScript objects, and will regenerate it (and re-associate a DOM object) with every change.

full explanation:

http://www.bennadel.com/blog/2556-using-track-by-with-ngrepeat-in-angularjs-1-2.htm

a more practical guide:

http://www.codelord.net/2014/04/15/improving-ng-repeat-performance-with-track-by/

(track by is available in angular > 1.2 )

How to find largest objects in a SQL Server database?

You may also use the following code:

USE AdventureWork
GO
CREATE TABLE #GetLargest 
(
  table_name    sysname ,
  row_count     INT,
  reserved_size VARCHAR(50),
  data_size     VARCHAR(50),
  index_size    VARCHAR(50),
  unused_size   VARCHAR(50)
)

SET NOCOUNT ON

INSERT #GetLargest

EXEC sp_msforeachtable 'sp_spaceused ''?'''

SELECT 
  a.table_name,
  a.row_count,
  COUNT(*) AS col_count,
  a.data_size
  FROM #GetLargest a
     INNER JOIN information_schema.columns b
     ON a.table_name collate database_default
     = b.table_name collate database_default
       GROUP BY a.table_name, a.row_count, a.data_size
       ORDER BY CAST(REPLACE(a.data_size, ' KB', '') AS integer) DESC

DROP TABLE #GetLargest

Android - SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length

Check if you have any element such as button or text view duplicated (copied twice) in the screen where this encounters. I did this unnoticed and had to face the same issue.

How do I redirect a user when a button is clicked?

It has been my experience that ASP MVC really does not like traditional use of button so much. Instead I use:

  <input type="button" class="addYourCSSClassHere" value="WordsOnButton" onclick="window.location= '@Url.Action( "ActionInControllerHere", "ControllerNameHere")'" />

Checking if a key exists in a JavaScript object?

The easiest way to check is

"key" in object

for example:

var obj = {
  a: 1,
  b: 2,
}
"a" in obj // true
"c" in obj // false

Return value as true implies that key exists in the object.

SecurityError: The operation is insecure - window.history.pushState()

I had the same problem when called another javascript file from a file without putting javascript "physical" address. I solved it by calling it same way from the html, example: "JS / archivo.js" instead of "archivo.js"

how to use font awesome in own css?

Instructions for Drupal 8 / FontAwesome 5

Create a YOUR_THEME_NAME_HERE.THEME file and place it in your themes directory (ie. your_site_name/themes/your_theme_name)

Paste this into the file, it is PHP code to find the Search Block and change the value to the UNICODE for the FontAwesome icon. You can find other characters at this link https://fontawesome.com/cheatsheet.

<?php
function YOUR_THEME_NAME_HERE_form_search_block_form_alter(&$form, &$form_state) {
  $form['keys']['#attributes']['placeholder'][] = t('Search');
  $form['actions']['submit']['#value'] = html_entity_decode('&#xf002;');
}
?>

Open the CSS file of your theme (ie. your_site_name/themes/your_theme_name/css/styles.css) and then paste this in which will change all input submit text to FontAwesome. Not sure if this will work if you also want to add text in the input button though for just an icon it is fine.

Make sure you import FontAwesome, add this at the top of the CSS file

@import url('https://use.fontawesome.com/releases/v5.0.9/css/all.css');

then add this in the CSS

input#edit-submit {
    font-family: 'Font Awesome\ 5 Free';
    background-color: transparent;
    border: 0;  
}

FLUSH ALL CACHES AND IT SHOULD WORK FINE

Add Google Font Effects

If you are using Google Web Fonts as well you can add also add effects to the icon (see more here https://developers.google.com/fonts/docs/getting_started#enabling_font_effects_beta). You need to import a Google Web Font including the effect(s) you would like to use first in the CSS so it will be

@import url('https://fonts.googleapis.com/css?family=Open+Sans:400,800&effect=3d-float');
@import url('https://use.fontawesome.com/releases/v5.0.9/css/all.css');

Then go back to your .THEME file and add the class for the 3D Float Effect so the code will now add a class to the input. There are different effects available. So just choose the effect you like, change the CSS for the font import and the change the value FONT-EFFECT-3D-FLOAT int the code below to font-effect-WHATEVER_EFFECT_HERE. Note effects are still in Beta and don't work in all browsers so read here before you try it https://developers.google.com/fonts/docs/getting_started#enabling_font_effects_beta

<?php
function YOUR_THEME_NAME_HERE_form_search_block_form_alter(&$form, &$form_state) {
  $form['keys']['#attributes']['placeholder'][] = t('Search');
  $form['actions']['submit']['#value'] = html_entity_decode('&#xf002;');
  $form['actions']['submit']['#attributes']['class'][] = 'font-effect-3d-float';
}
?>

How to create a toggle button in Bootstrap

Bootstrap 4 solution

bootstrap 4 ships built-in toggle. Here is the documentation. https://getbootstrap.com/docs/4.3/components/forms/#switches

enter image description here

Cloning a private Github repo

I needed a non-interactive method for cloning a private repo.

Inspired by this issue: https://github.com/github/hub/issues/1644

Step 1.

Create a personal access token in the github developer settings: https://github.com/settings/tokens

Step 2.

git clone https://$token:[email protected]/$username/$repo.git

Insert and set value with max()+1 problems

Correct, you can not modify and select from the same table in the same query. You would have to perform the above in two separate queries.

The best way is to use a transaction but if your not using innodb tables then next best is locking the tables and then performing your queries. So:

Lock tables customers write;

$max = SELECT MAX( customer_id ) FROM customers;

Grab the max id and then perform the insert

INSERT INTO customers( customer_id, firstname, surname )
VALUES ($max+1 , 'jim', 'sock')

unlock tables;

Oracle "ORA-01008: not all variables bound" Error w/ Parameters

It seems daft, but I think when you use the same bind variable twice you have to set it twice:

cmd.Parameters.Add("VarA", "24");
cmd.Parameters.Add("VarB", "test");
cmd.Parameters.Add("VarB", "test");
cmd.Parameters.Add("VarC", "1234");
cmd.Parameters.Add("VarC", "1234");

Certainly that's true with Native Dynamic SQL in PL/SQL:

SQL> begin
  2     execute immediate 'select * from emp where ename=:name and ename=:name'
  3     using 'KING';
  4  end;
  5  /
begin
*
ERROR at line 1:
ORA-01008: not all variables bound


SQL> begin
  2     execute immediate 'select * from emp where ename=:name and ename=:name' 
  3     using 'KING', 'KING';
  4  end;
  5  /

PL/SQL procedure successfully completed.

How to track down a "double free or corruption" error

I know this is a very old thread, but it is the top google search for this error, and none of the responses mention a common cause of the error.

Which is closing a file you've already closed.

If you're not paying attention and have two different functions close the same file, then the second one will generate this error.

How to filter a RecyclerView with a SearchView

Introduction

Since it is not really clear from your question what exactly you are having trouble with, I wrote up this quick walkthrough about how to implement this feature; if you still have questions feel free to ask.

I have a working example of everything I am talking about here in this GitHub Repository.
If you want to know more about the example project visit the project homepage.

In any case the result should looks something like this:

demo image

If you first want to play around with the demo app you can install it from the Play Store:

Get it on Google Play

Anyway lets get started.


Setting up the SearchView

In the folder res/menu create a new file called main_menu.xml. In it add an item and set the actionViewClass to android.support.v7.widget.SearchView. Since you are using the support library you have to use the namespace of the support library to set the actionViewClass attribute. Your xml file should look something like this:

<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto">

    <item android:id="@+id/action_search"
          android:title="@string/action_search"
          app:actionViewClass="android.support.v7.widget.SearchView"
          app:showAsAction="always"/>

</menu>

In your Fragment or Activity you have to inflate this menu xml like usual, then you can look for the MenuItem which contains the SearchView and implement the OnQueryTextListener which we are going to use to listen for changes to the text entered into the SearchView:

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu_main, menu);

    final MenuItem searchItem = menu.findItem(R.id.action_search);
    final SearchView searchView = (SearchView) searchItem.getActionView();
    searchView.setOnQueryTextListener(this);

    return true;
}

@Override
public boolean onQueryTextChange(String query) {
    // Here is where we are going to implement the filter logic
    return false;
}

@Override
public boolean onQueryTextSubmit(String query) {
    return false;
}

And now the SearchView is ready to be used. We will implement the filter logic later on in onQueryTextChange() once we are finished implementing the Adapter.


Setting up the Adapter

First and foremost this is the model class I am going to use for this example:

public class ExampleModel {

    private final long mId;
    private final String mText;

    public ExampleModel(long id, String text) {
        mId = id;
        mText = text;
    }

    public long getId() {
        return mId;
    }

    public String getText() {
        return mText;
    }
}

It's just your basic model which will display a text in the RecyclerView. This is the layout I am going to use to display the text:

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">

    <data>

        <variable
            name="model"
            type="com.github.wrdlbrnft.searchablerecyclerviewdemo.ui.models.ExampleModel"/>

    </data>

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="?attr/selectableItemBackground"
        android:clickable="true">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="8dp"
            android:text="@{model.text}"/>

    </FrameLayout>

</layout>

As you can see I use Data Binding. If you have never worked with data binding before don't be discouraged! It's very simple and powerful, however I can't explain how it works in the scope of this answer.

This is the ViewHolder for the ExampleModel class:

public class ExampleViewHolder extends RecyclerView.ViewHolder {

    private final ItemExampleBinding mBinding;

    public ExampleViewHolder(ItemExampleBinding binding) {
        super(binding.getRoot());
        mBinding = binding;
    }

    public void bind(ExampleModel item) {
        mBinding.setModel(item);
    }
}

Again nothing special. It just uses data binding to bind the model class to this layout as we have defined in the layout xml above.

Now we can finally come to the really interesting part: Writing the Adapter. I am going to skip over the basic implementation of the Adapter and am instead going to concentrate on the parts which are relevant for this answer.

But first there is one thing we have to talk about: The SortedList class.


SortedList

The SortedList is a completely amazing tool which is part of the RecyclerView library. It takes care of notifying the Adapter about changes to the data set and does so it a very efficient way. The only thing it requires you to do is specify an order of the elements. You need to do that by implementing a compare() method which compares two elements in the SortedList just like a Comparator. But instead of sorting a List it is used to sort the items in the RecyclerView!

The SortedList interacts with the Adapter through a Callback class which you have to implement:

private final SortedList.Callback<ExampleModel> mCallback = new SortedList.Callback<ExampleModel>() {

    @Override
    public void onInserted(int position, int count) {
         mAdapter.notifyItemRangeInserted(position, count);
    }

    @Override
    public void onRemoved(int position, int count) {
        mAdapter.notifyItemRangeRemoved(position, count);
    }

    @Override
    public void onMoved(int fromPosition, int toPosition) {
        mAdapter.notifyItemMoved(fromPosition, toPosition);
    }

    @Override
    public void onChanged(int position, int count) {
        mAdapter.notifyItemRangeChanged(position, count);
    }

    @Override
    public int compare(ExampleModel a, ExampleModel b) {
        return mComparator.compare(a, b);
    }

    @Override
    public boolean areContentsTheSame(ExampleModel oldItem, ExampleModel newItem) {
        return oldItem.equals(newItem);
    }

    @Override
    public boolean areItemsTheSame(ExampleModel item1, ExampleModel item2) {
        return item1.getId() == item2.getId();
    }
}

In the methods at the top of the callback like onMoved, onInserted, etc. you have to call the equivalent notify method of your Adapter. The three methods at the bottom compare, areContentsTheSame and areItemsTheSame you have to implement according to what kind of objects you want to display and in what order these objects should appear on the screen.

Let's go through these methods one by one:

@Override
public int compare(ExampleModel a, ExampleModel b) {
    return mComparator.compare(a, b);
}

This is the compare() method I talked about earlier. In this example I am just passing the call to a Comparator which compares the two models. If you want the items to appear in alphabetical order on the screen. This comparator might look like this:

private static final Comparator<ExampleModel> ALPHABETICAL_COMPARATOR = new Comparator<ExampleModel>() {
    @Override
    public int compare(ExampleModel a, ExampleModel b) {
        return a.getText().compareTo(b.getText());
    }
};

Now let's take a look at the next method:

@Override
public boolean areContentsTheSame(ExampleModel oldItem, ExampleModel newItem) {
    return oldItem.equals(newItem);
}

The purpose of this method is to determine if the content of a model has changed. The SortedList uses this to determine if a change event needs to be invoked - in other words if the RecyclerView should crossfade the old and new version. If you model classes have a correct equals() and hashCode() implementation you can usually just implement it like above. If we add an equals() and hashCode() implementation to the ExampleModel class it should look something like this:

public class ExampleModel implements SortedListAdapter.ViewModel {

    private final long mId;
    private final String mText;

    public ExampleModel(long id, String text) {
        mId = id;
        mText = text;
    }

    public long getId() {
        return mId;
    }

    public String getText() {
        return mText;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        ExampleModel model = (ExampleModel) o;

        if (mId != model.mId) return false;
        return mText != null ? mText.equals(model.mText) : model.mText == null;

    }

    @Override
    public int hashCode() {
        int result = (int) (mId ^ (mId >>> 32));
        result = 31 * result + (mText != null ? mText.hashCode() : 0);
        return result;
    }
}

Quick side note: Most IDE's like Android Studio, IntelliJ and Eclipse have functionality to generate equals() and hashCode() implementations for you at the press of a button! So you don't have to implement them yourself. Look up on the internet how it works in your IDE!

Now let's take a look at the last method:

@Override
public boolean areItemsTheSame(ExampleModel item1, ExampleModel item2) {
    return item1.getId() == item2.getId();
}

The SortedList uses this method to check if two items refer to the same thing. In simplest terms (without explaining how the SortedList works) this is used to determine if an object is already contained in the List and if either an add, move or change animation needs to be played. If your models have an id you would usually compare just the id in this method. If they don't you need to figure out some other way to check this, but however you end up implementing this depends on your specific app. Usually it is the simplest option to give all models an id - that could for example be the primary key field if you are querying the data from a database.

With the SortedList.Callback correctly implemented we can create an instance of the SortedList:

final SortedList<ExampleModel> list = new SortedList<>(ExampleModel.class, mCallback);

As the first parameter in the constructor of the SortedList you need to pass the class of your models. The other parameter is just the SortedList.Callback we defined above.

Now let's get down to business: If we implement the Adapter with a SortedList it should look something like this:

public class ExampleAdapter extends RecyclerView.Adapter<ExampleViewHolder> {

    private final SortedList<ExampleModel> mSortedList = new SortedList<>(ExampleModel.class, new SortedList.Callback<ExampleModel>() {
        @Override
        public int compare(ExampleModel a, ExampleModel b) {
            return mComparator.compare(a, b);
        }

        @Override
        public void onInserted(int position, int count) {
            notifyItemRangeInserted(position, count);
        }

        @Override
        public void onRemoved(int position, int count) {
            notifyItemRangeRemoved(position, count);
        }

        @Override
        public void onMoved(int fromPosition, int toPosition) {
            notifyItemMoved(fromPosition, toPosition);
        }

        @Override
        public void onChanged(int position, int count) {
            notifyItemRangeChanged(position, count);
        }

        @Override
        public boolean areContentsTheSame(ExampleModel oldItem, ExampleModel newItem) {
            return oldItem.equals(newItem);
        }

        @Override
        public boolean areItemsTheSame(ExampleModel item1, ExampleModel item2) {
            return item1.getId() == item2.getId();
        }
    });

    private final LayoutInflater mInflater;
    private final Comparator<ExampleModel> mComparator;

    public ExampleAdapter(Context context, Comparator<ExampleModel> comparator) {
        mInflater = LayoutInflater.from(context);
        mComparator = comparator;
    }

    @Override
    public ExampleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        final ItemExampleBinding binding = ItemExampleBinding.inflate(inflater, parent, false);
        return new ExampleViewHolder(binding);
    }

    @Override
    public void onBindViewHolder(ExampleViewHolder holder, int position) {
        final ExampleModel model = mSortedList.get(position);
        holder.bind(model);
    }

    @Override
    public int getItemCount() {
        return mSortedList.size();
    }
}

The Comparator used to sort the item is passed in through the constructor so we can use the same Adapter even if the items are supposed to be displayed in a different order.

Now we are almost done! But we first need a way to add or remove items to the Adapter. For this purpose we can add methods to the Adapter which allow us to add and remove items to the SortedList:

public void add(ExampleModel model) {
    mSortedList.add(model);
}

public void remove(ExampleModel model) {
    mSortedList.remove(model);
}

public void add(List<ExampleModel> models) {
    mSortedList.addAll(models);
}

public void remove(List<ExampleModel> models) {
    mSortedList.beginBatchedUpdates();
    for (ExampleModel model : models) {
        mSortedList.remove(model);
    }
    mSortedList.endBatchedUpdates();
}

We don't need to call any notify methods here because the SortedList already does this for through the SortedList.Callback! Aside from that the implementation of these methods is pretty straight forward with one exception: the remove method which removes a List of models. Since the SortedList has only one remove method which can remove a single object we need to loop over the list and remove the models one by one. Calling beginBatchedUpdates() at the beginning batches all the changes we are going to make to the SortedList together and improves performance. When we call endBatchedUpdates() the RecyclerView is notified about all the changes at once.

Additionally what you have to understand is that if you add an object to the SortedList and it is already in the SortedList it won't be added again. Instead the SortedList uses the areContentsTheSame() method to figure out if the object has changed - and if it has the item in the RecyclerView will be updated.

Anyway, what I usually prefer is one method which allows me to replace all items in the RecyclerView at once. Remove everything which is not in the List and add all items which are missing from the SortedList:

public void replaceAll(List<ExampleModel> models) {
    mSortedList.beginBatchedUpdates();
    for (int i = mSortedList.size() - 1; i >= 0; i--) {
        final ExampleModel model = mSortedList.get(i);
        if (!models.contains(model)) {
            mSortedList.remove(model);
        }
    }
    mSortedList.addAll(models);
    mSortedList.endBatchedUpdates();
}

This method again batches all updates together to increase performance. The first loop is in reverse since removing an item at the start would mess up the indexes of all items that come up after it and this can lead in some instances to problems like data inconsistencies. After that we just add the List to the SortedList using addAll() to add all items which are not already in the SortedList and - just like I described above - update all items that are already in the SortedList but have changed.

And with that the Adapter is complete. The whole thing should look something like this:

public class ExampleAdapter extends RecyclerView.Adapter<ExampleViewHolder> {

    private final SortedList<ExampleModel> mSortedList = new SortedList<>(ExampleModel.class, new SortedList.Callback<ExampleModel>() {
        @Override
        public int compare(ExampleModel a, ExampleModel b) {
            return mComparator.compare(a, b);
        }

        @Override
        public void onInserted(int position, int count) {
            notifyItemRangeInserted(position, count);
        }

        @Override
        public void onRemoved(int position, int count) {
            notifyItemRangeRemoved(position, count);
        }

        @Override
        public void onMoved(int fromPosition, int toPosition) {
            notifyItemMoved(fromPosition, toPosition);
        }

        @Override
        public void onChanged(int position, int count) {
            notifyItemRangeChanged(position, count);
        }

        @Override
        public boolean areContentsTheSame(ExampleModel oldItem, ExampleModel newItem) {
            return oldItem.equals(newItem);
        }

        @Override
        public boolean areItemsTheSame(ExampleModel item1, ExampleModel item2) {
            return item1 == item2;
        }
    });

    private final Comparator<ExampleModel> mComparator;
    private final LayoutInflater mInflater;

    public ExampleAdapter(Context context, Comparator<ExampleModel> comparator) {
        mInflater = LayoutInflater.from(context);
        mComparator = comparator;
    }

    @Override
    public ExampleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        final ItemExampleBinding binding = ItemExampleBinding.inflate(mInflater, parent, false);
        return new ExampleViewHolder(binding);
    }

    @Override
    public void onBindViewHolder(ExampleViewHolder holder, int position) {
        final ExampleModel model = mSortedList.get(position);
        holder.bind(model);
    }

    public void add(ExampleModel model) {
        mSortedList.add(model);
    }

    public void remove(ExampleModel model) {
        mSortedList.remove(model);
    }

    public void add(List<ExampleModel> models) {
        mSortedList.addAll(models);
    }

    public void remove(List<ExampleModel> models) {
        mSortedList.beginBatchedUpdates();
        for (ExampleModel model : models) {
            mSortedList.remove(model);
        }
        mSortedList.endBatchedUpdates();
    }

    public void replaceAll(List<ExampleModel> models) {
        mSortedList.beginBatchedUpdates();
        for (int i = mSortedList.size() - 1; i >= 0; i--) {
            final ExampleModel model = mSortedList.get(i);
            if (!models.contains(model)) {
                mSortedList.remove(model);
            }
        }
        mSortedList.addAll(models);
        mSortedList.endBatchedUpdates();
    }

    @Override
    public int getItemCount() {
        return mSortedList.size();
    }
}

The only thing missing now is to implement the filtering!


Implementing the filter logic

To implement the filter logic we first have to define a List of all possible models. For this example I create a List of ExampleModel instances from an array of movies:

private static final String[] MOVIES = new String[]{
        ...
};

private static final Comparator<ExampleModel> ALPHABETICAL_COMPARATOR = new Comparator<ExampleModel>() {
    @Override
    public int compare(ExampleModel a, ExampleModel b) {
        return a.getText().compareTo(b.getText());
    }
};

private ExampleAdapter mAdapter;
private List<ExampleModel> mModels;
private RecyclerView mRecyclerView;

    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mBinding = DataBindingUtil.setContentView(this, R.layout.activity_main);

    mAdapter = new ExampleAdapter(this, ALPHABETICAL_COMPARATOR);

    mBinding.recyclerView.setLayoutManager(new LinearLayoutManager(this));
    mBinding.recyclerView.setAdapter(mAdapter);

    mModels = new ArrayList<>();
    for (String movie : MOVIES) {
        mModels.add(new ExampleModel(movie));
    }
    mAdapter.add(mModels);
}

Nothing special going on here, we just instantiate the Adapter and set it to the RecyclerView. After that we create a List of models from the movie names in the MOVIES array. Then we add all the models to the SortedList.

Now we can go back to onQueryTextChange() which we defined earlier and start implementing the filter logic:

@Override
public boolean onQueryTextChange(String query) {
    final List<ExampleModel> filteredModelList = filter(mModels, query);
    mAdapter.replaceAll(filteredModelList);
    mBinding.recyclerView.scrollToPosition(0);
    return true;
}

This is again pretty straight forward. We call the method filter() and pass in the List of ExampleModels as well as the query string. We then call replaceAll() on the Adapter and pass in the filtered List returned by filter(). We also have to call scrollToPosition(0) on the RecyclerView to ensure that the user can always see all items when searching for something. Otherwise the RecyclerView might stay in a scrolled down position while filtering and subsequently hide a few items. Scrolling to the top ensures a better user experience while searching.

The only thing left to do now is to implement filter() itself:

private static List<ExampleModel> filter(List<ExampleModel> models, String query) {
    final String lowerCaseQuery = query.toLowerCase();

    final List<ExampleModel> filteredModelList = new ArrayList<>();
    for (ExampleModel model : models) {
        final String text = model.getText().toLowerCase();
        if (text.contains(lowerCaseQuery)) {
            filteredModelList.add(model);
        }
    }
    return filteredModelList;
}

The first thing we do here is call toLowerCase() on the query string. We don't want our search function to be case sensitive and by calling toLowerCase() on all strings we compare we can ensure that we return the same results regardless of case. It then just iterates through all the models in the List we passed into it and checks if the query string is contained in the text of the model. If it is then the model is added to the filtered List.

And that's it! The above code will run on API level 7 and above and starting with API level 11 you get item animations for free!

I realize that this is a very detailed description which probably makes this whole thing seem more complicated than it really is, but there is a way we can generalize this whole problem and make implementing an Adapter based on a SortedList much simpler.


Generalizing the problem and simplifying the Adapter

In this section I am not going to go into much detail - partly because I am running up against the character limit for answers on Stack Overflow but also because most of it already explained above - but to summarize the changes: We can implemented a base Adapter class which already takes care of dealing with the SortedList as well as binding models to ViewHolder instances and provides a convenient way to implement an Adapter based on a SortedList. For that we have to do two things:

  • We need to create a ViewModel interface which all model classes have to implement
  • We need to create a ViewHolder subclass which defines a bind() method the Adapter can use to bind models automatically.

This allows us to just focus on the content which is supposed to be displayed in the RecyclerView by just implementing the models and there corresponding ViewHolder implementations. Using this base class we don't have to worry about the intricate details of the Adapter and its SortedList.

SortedListAdapter

Because of the character limit for answers on StackOverflow I can't go through each step of implementing this base class or even add the full source code here, but you can find the full source code of this base class - I called it SortedListAdapter - in this GitHub Gist.

To make your life simple I have published a library on jCenter which contains the SortedListAdapter! If you want to use it then all you need to do is add this dependency to your app's build.gradle file:

compile 'com.github.wrdlbrnft:sorted-list-adapter:0.2.0.1'

You can find more information about this library on the library homepage.

Using the SortedListAdapter

To use the SortedListAdapter we have to make two changes:

  • Change the ViewHolder so that it extends SortedListAdapter.ViewHolder. The type parameter should be the model which should be bound to this ViewHolder - in this case ExampleModel. You have to bind data to your models in performBind() instead of bind().

    public class ExampleViewHolder extends SortedListAdapter.ViewHolder<ExampleModel> {
    
        private final ItemExampleBinding mBinding;
    
        public ExampleViewHolder(ItemExampleBinding binding) {
            super(binding.getRoot());
            mBinding = binding;
        }
    
        @Override
        protected void performBind(ExampleModel item) {
            mBinding.setModel(item);
        }
    }
    
  • Make sure that all your models implement the ViewModel interface:

    public class ExampleModel implements SortedListAdapter.ViewModel {
        ...
    }
    

After that we just have to update the ExampleAdapter to extend SortedListAdapter and remove everything we don't need anymore. The type parameter should be the type of model you are working with - in this case ExampleModel. But if you are working with different types of models then set the type parameter to ViewModel.

public class ExampleAdapter extends SortedListAdapter<ExampleModel> {

    public ExampleAdapter(Context context, Comparator<ExampleModel> comparator) {
        super(context, ExampleModel.class, comparator);
    }

    @Override
    protected ViewHolder<? extends ExampleModel> onCreateViewHolder(LayoutInflater inflater, ViewGroup parent, int viewType) {
        final ItemExampleBinding binding = ItemExampleBinding.inflate(inflater, parent, false);
        return new ExampleViewHolder(binding);
    }

    @Override
    protected boolean areItemsTheSame(ExampleModel item1, ExampleModel item2) {
        return item1.getId() == item2.getId();
    }

    @Override
    protected boolean areItemContentsTheSame(ExampleModel oldItem, ExampleModel newItem) {
        return oldItem.equals(newItem);
    }
}

After that we are done! However one last thing to mention: The SortedListAdapter does not have the same add(), remove() or replaceAll() methods our original ExampleAdapter had. It uses a separate Editor object to modify the items in the list which can be accessed through the edit() method. So if you want to remove or add items you have to call edit() then add and remove the items on this Editor instance and once you are done, call commit() on it to apply the changes to the SortedList:

mAdapter.edit()
        .remove(modelToRemove)
        .add(listOfModelsToAdd)
        .commit();

All changes you make this way are batched together to increase performance. The replaceAll() method we implemented in the chapters above is also present on this Editor object:

mAdapter.edit()
        .replaceAll(mModels)
        .commit();

If you forget to call commit() then none of your changes will be applied!

Could not load file or assembly 'System.Web.Mvc'

I ran into this same issue trying to deploy my MVC3 Razor web application on GoDaddy shared hosting. There are some additional .dlls that need to be referenced. Details here: http://paulmason.biz/?p=108

Basically you need to add references to the following in addition to the ones listed in @Haacked's post and set them to deploy locally as described.

  • Microsoft.Web.Infrastructure
  • System.Web.Razor
  • System.Web.WebPages.Deployment
  • System.Web.WebPages.Razor

How to display an IFRAME inside a jQuery UI dialog

There are multiple ways you can do this but I am not sure which one is the best practice. The first approach is you can append an iFrame in the dialog container on the fly with your given link:

$("#dialog").append($("<iframe />").attr("src", "your link")).dialog({dialogoptions});

Another would be to load the content of your external link into the dialog container using ajax.

$("#dialog").load("yourajaxhandleraddress.htm").dialog({dialogoptions});

Both works fine but depends on the external content.

How to tell if a string contains a certain character in JavaScript?

Check if string is alphanumeric or alphanumeric + some allowed chars

The fastest alphanumeric method is likely as mentioned at: Best way to alphanumeric check in Javascript as it operates on number ranges directly.

Then, to allow a few other extra chars sanely we can just put them in a Set for fast lookup.

I believe that this implementation will deal with surrogate pairs correctly correctly.

#!/usr/bin/env node

const assert = require('assert');

const char_is_alphanumeric = function(c) {
  let code = c.codePointAt(0);
  return (
    // 0-9
    (code > 47 && code < 58) ||
    // A-Z
    (code > 64 && code < 91) ||
    // a-z
    (code > 96 && code < 123)
  )
}

const is_alphanumeric = function (str) {
  for (let c of str) {
    if (!char_is_alphanumeric(c)) {
      return false;
    }
  }
  return true;
};

// Arbitrarily defined as alphanumeric or '-' or '_'.
const is_almost_alphanumeric = function (str) {
  for (let c of str) {
    if (
      !char_is_alphanumeric(c) &&
      !is_almost_alphanumeric.almost_chars.has(c)
    ) {
      return false;
    }
  }
  return true;
};
is_almost_alphanumeric.almost_chars = new Set(['-', '_']);

assert( is_alphanumeric('aB0'));
assert(!is_alphanumeric('aB0_-'));
assert(!is_alphanumeric('aB0_-*'));
assert(!is_alphanumeric('??'));

assert( is_almost_alphanumeric('aB0'));
assert( is_almost_alphanumeric('aB0_-'));
assert(!is_almost_alphanumeric('aB0_-*'));
assert(!is_almost_alphanumeric('??'));

GitHub upstream.

Tested in Node.js v10.15.1.

Sass calculate percent minus px

Sorry for reviving old thread - Compass' stretch with an :after pseudo-selector might suit your purpose - eg. if you want a div to fill width from left to (50% + 10px) of screen you could use (in SASS indented syntax):

.example
    background: red
    +stretch(0, -10px, 0, 0)
    &:after
        +stretch(0, 0, 0, 50%)
        content: ' '
        background: blue

The :after element fills 50% to the right of .example (leaving 50% available for .example's width), then .example is stretched to that width plus 10px.

Uncaught SyntaxError: Failed to execute 'querySelector' on 'Document'

Although this is valid in HTML, you can't use an ID starting with an integer in CSS selectors.

As pointed out, you can use getElementById instead, but you can also still achieve the same with a querySelector:

document.querySelector("[id='22']")

Is it possible to Turn page programmatically in UIPageViewController?

For single page, I just edited the answer of @Jack Humphries

-(void)viewDidLoad
{
  counter = 0;
}
-(IBAction)buttonClick:(id)sender
{
  counter++;
  DataViewController *secondVC = [self.modelController viewControllerAtIndex:counter storyboard:self.storyboard];
  NSArray *viewControllers = nil;          
  viewControllers = [NSArray arrayWithObjects:secondVC, nil];          
  [self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:NULL];
}

JQuery: Change value of hidden input field

Seems to work

$(".selector").change(function() {

    var $value = $(this).val();

    var $title = $(this).children('option[value='+$value+']').html();

    $('#bacon').val($title);

});

Just check with your firebug. And don't put css on hidden input.

How to initialize an array in Kotlin with values?

Declare int array at global

var numbers= intArrayOf()

next onCreate method initialize your array with value

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    //create your int array here
    numbers= intArrayOf(10,20,30,40,50)
}

Declaring functions in JSP?

You need to enclose that in <%! %> as follows:

<%!

public String getQuarter(int i){
String quarter;
switch(i){
        case 1: quarter = "Winter";
        break;

        case 2: quarter = "Spring";
        break;

        case 3: quarter = "Summer I";
        break;

        case 4: quarter = "Summer II";
        break;

        case 5: quarter = "Fall";
        break;

        default: quarter = "ERROR";
}

return quarter;
}

%>

You can then invoke the function within scriptlets or expressions:

<%
     out.print(getQuarter(4));
%>

or

<%= getQuarter(17) %>

How to set button click effect in Android?

Or using only one background image you can achive the click effect by using setOnTouchListener

Two ways

((Button)findViewById(R.id.testBth)).setOnTouchListener(new OnTouchListener() {

      @Override
        public boolean onTouch(View v, MotionEvent event) {
          switch (event.getAction()) {
              case MotionEvent.ACTION_DOWN: {
                  Button view = (Button) v;
                  view.getBackground().setColorFilter(0x77000000, PorterDuff.Mode.SRC_ATOP);
                  v.invalidate();
                  break;
              }
              case MotionEvent.ACTION_UP:
                  // Your action here on button click
              case MotionEvent.ACTION_CANCEL: {
                  Button view = (Button) v;
                  view.getBackground().clearColorFilter();
                  view.invalidate();
                  break;
              }
          }
          return true;
        }
});

enter image description here

And if you don't want to use setOnTouchLister, the another way of achieving this is

    myButton.getBackground().setColorFilter(.setColorFilter(0xF00, Mode.MULTIPLY);

    StateListDrawable listDrawable = new StateListDrawable();
    listDrawable.addState(new int[] {android.R.attr.state_pressed}, drawablePressed);
    listDrawable.addState(new int[] {android.R.attr.defaultValue}, myButton);

    myButton.setBackgroundDrawable(listDrawable);

Oracle JDBC intermittent Connection Issue

As per Bug https://bugs.openjdk.java.net/browse/JDK-6202721

Java will not consder -Djava.security.egd=file:/dev/urandom

It should be -Djava.security.egd=file:/dev/./urandom

How do I list all the files in a directory and subdirectories in reverse chronological order?

Try this one:

find . -type f -printf "%T@ %p\n" | sort -nr | cut -d\  -f2-

CSS flexbox vertically/horizontally center image WITHOUT explicitely defining parent height

Just add the following rules to the parent element:

display: flex;
justify-content: center; /* align horizontal */
align-items: center; /* align vertical */

Here's a sample demo (Resize window to see the image align)

Browser support for Flexbox nowadays is quite good.

For cross-browser compatibility for display: flex and align-items, you can add the older flexbox syntax as well:

display: -webkit-box;
display: -webkit-flex;
display: -moz-box;
display: -ms-flexbox;
display: flex;
-webkit-flex-align: center;
-ms-flex-align: center;
-webkit-align-items: center;
align-items: center;

method in class cannot be applied to given types

I think you want something like this. The formatting is off, but it should give the essential information you want.

   import java.util.Scanner;
public class BookstoreCredit 
{

   public static void computeDiscount(String name, double gpa) 
   {
      double credits;
      credits = gpa * 10;
      System.out.println(name + " your GPA is " +
         gpa + " so your credit is $" + credits);
   
   }

   public static void main (String args[]) 
   {
      String studentName;
      double gradeAverage;
      Scanner inputDevice = new Scanner(System.in);
      System.out.println("Enter Student name: ");
      studentName = inputDevice.nextLine();
      System.out.println("Enter student GPA: ");
      gradeAverage = inputDevice.nextDouble();  
      
      computeDiscount(studentName, gradeAverage);
   }
}

Python urllib2, basic HTTP authentication, and tr.im

Really cheap solution:

urllib.urlopen('http://user:[email protected]/api')

(which you may decide is not suitable for a number of reasons, like security of the url)

Github API example:

>>> import urllib, json
>>> result = urllib.urlopen('https://personal-access-token:[email protected]/repos/:owner/:repo')
>>> r = json.load(result.fp)
>>> result.close()

Do checkbox inputs only post data if they're checked?

Having the same problem with unchecked checkboxes that will not be send on forms submit, I came out with a another solution than mirror the checkbox items.

Getting all unchecked checkboxes with

var checkboxQueryString;

$form.find ("input[type=\"checkbox\"]:not( \":checked\")" ).each(function( i, e ) {
  checkboxQueryString += "&" + $( e ).attr( "name" ) + "=N"
});

Rendering partial view on button click in ASP.NET MVC

Change the button to

<button id="search">Search</button>

and add the following script

var url = '@Url.Action("DisplaySearchResults", "Search")';
$('#search').click(function() {
  var keyWord = $('#Keyword').val();
  $('#searchResults').load(url, { searchText: keyWord });
})

and modify the controller method to accept the search text

public ActionResult DisplaySearchResults(string searchText)
{
  var model = // build list based on parameter searchText
   return PartialView("SearchResults", model);
}

The jQuery .load method calls your controller method, passing the value of the search text and updates the contents of the <div> with the partial view.

Side note: The use of a <form> tag and @Html.ValidationSummary() and @Html.ValidationMessageFor() are probably not necessary here. Your never returning the Index view so ValidationSummary makes no sense and I assume you want a null search text to return all results, and in any case you do not have any validation attributes for property Keyword so there is nothing to validate.

Edit

Based on OP's comments that SearchCriterionModel will contain multiple properties with validation attributes, then the approach would be to include a submit button and handle the forms .submit() event

<input type="submit" value="Search" />

var url = '@Url.Action("DisplaySearchResults", "Search")';
$('form').submit(function() {
  if (!$(this).valid()) { 
    return false; // prevent the ajax call if validation errors
  }
  var form = $(this).serialize();
  $('#searchResults').load(url, form);
  return false; // prevent the default submit action
})

and the controller method would be

public ActionResult DisplaySearchResults(SearchCriterionModel criteria)
{
  var model = // build list based on the properties of criteria
  return PartialView("SearchResults", model);
}

How can I read a text file from the SD card in Android?

You should have READ_EXTERNAL_STORAGE permission for reading sdcard. Add permission in manifest.xml

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

From android 6.0 or higher, your app must ask user to grant the dangerous permissions at runtime. Please refer this link Permissions overview

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
    if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 0);
    }
}

What is a "bundle" in an Android application

bundle is used to share data between activities , and to save state of app in oncreate() method so that app will come to know where it was stopped ... I hope it helps :)

Rank function in MySQL

While the most upvoted answer ranks, it doesn't partition, You can do a self Join to get the whole thing partitioned also:

SELECT    a.first_name,
      a.age,
      a.gender,
        count(b.age)+1 as rank
FROM  person a left join person b on a.age>b.age and a.gender=b.gender 
group by  a.first_name,
      a.age,
      a.gender

Use Case

CREATE TABLE person (id int, first_name varchar(20), age int, gender char(1));

INSERT INTO person VALUES (1, 'Bob', 25, 'M');
INSERT INTO person VALUES (2, 'Jane', 20, 'F');
INSERT INTO person VALUES (3, 'Jack', 30, 'M');
INSERT INTO person VALUES (4, 'Bill', 32, 'M');
INSERT INTO person VALUES (5, 'Nick', 22, 'M');
INSERT INTO person VALUES (6, 'Kathy', 18, 'F');
INSERT INTO person VALUES (7, 'Steve', 36, 'M');
INSERT INTO person VALUES (8, 'Anne', 25, 'F');

Answer:

Bill    32  M   4
Bob     25  M   2
Jack    30  M   3
Nick    22  M   1
Steve   36  M   5
Anne    25  F   3
Jane    20  F   2
Kathy   18  F   1

Passing a Bundle on startActivity()?

You can pass values from one activity to another activity using the Bundle. In your current activity, create a bundle and set the bundle for the particular value and pass that bundle to the intent.

Intent intent = new Intent(this,NewActivity.class);
Bundle bundle = new Bundle();
bundle.putString(key,value);
intent.putExtras(bundle);
startActivity(intent);

Now in your NewActivity, you can get this bundle and retrive your value.

Bundle bundle = getArguments();
String value = bundle.getString(key);

You can also pass data through the intent. In your current activity, set intent like this,

Intent intent = new Intent(this,NewActivity.class);
intent.putExtra(key,value);
startActivity(intent);

Now in your NewActivity, you can get that value from intent like this,

String value = getIntent().getExtras().getString(key);

Why "net use * /delete" does not work but waits for confirmation in my PowerShell script?

Try this:

net use * /delete /y

The /y key makes it select Yes in prompt silently

How to get the first 2 letters of a string in Python?

In python strings are list of characters, but they are not explicitly list type, just list-like (i.e. it can be treated like a list). More formally, they're known as sequence (see http://docs.python.org/2/library/stdtypes.html#sequence-types-str-unicode-list-tuple-bytearray-buffer-xrange):

>>> a = 'foo bar'
>>> isinstance(a, list)
False
>>> isinstance(a, str)
True

Since strings are sequence, you can use slicing to access parts of the list, denoted by list[start_index:end_index] see Explain Python's slice notation . For example:

>>> a = [1,2,3,4]
>>> a[0]
1 # first element, NOT a sequence.
>>> a[0:1]
[1] # a slice from first to second, a list, i.e. a sequence.
>>> a[0:2]
[1, 2]
>>> a[:2]
[1, 2]

>>> x = "foo bar"
>>> x[0:2]
'fo'
>>> x[:2]
'fo'

When undefined, the slice notation takes the starting position as the 0, and end position as len(sequence).

In the olden C days, it's an array of characters, the whole issue of dynamic vs static list sounds like legend now, see Python List vs. Array - when to use?

No connection string named 'MyEntities' could be found in the application config file

The best way I just found to address this is to temporarily set that project (most likely a class library) to the startup project. This forces the package manager console to use that project as it's config source. part of the reason it is set up this way is because of the top down model that th econfig files usually follow. The rule of thumb is that the project that is closest to the client (MVC application for instance) is the web.config or app.config that will be used.

Return value from exec(@sql)

Was playing with this today... I beleive you can also use @@ROWCOUNT, like this:

DECLARE @SQL VARCHAR(50)
DECLARE @Rowcount INT
SET @SQL = 'SELECT 1 UNION SELECT 2'
EXEC(@SQL)
SET @Rowcount = @@ROWCOUNT
SELECT @Rowcount

Then replace the 'SELECT 1 UNION SELECT 2' with your actual select without the count. I'd suggest just putting 1 in your select, like this:

SELECT 1
FROM dbo.Comm_Services
WHERE....
....

(as opposed to putting SELECT *)

Hope that helps.

Calculate compass bearing / heading to location in Android

I'm no expert in map-reading / navigation and so on but surely 'directions' are absolute and not relative or in reality, they are relative to N or S which themselves are fixed/absolute.

Example: Suppose an imaginary line drawn between you and your destination corresponds with 'absolute' SE (a bearing of 135 degrees relative to magnetic N). Now suppose your phone is pointing NW - if you draw an imaginary line from an imaginary object on the horizon to your destination, it will pass through your location and have an angle of 180 degrees. Now 180 degrees in the sense of a compass actually refers to S but the destination is not 'due S' of the imaginary object your phone is pointing at and, moreover, if you travelled to that imaginary point, your destination would still be SE of where you moved to.

In reality, the 180 degree line actually tells you the destination is 'behind you' relative to the way the phone (and presumably you) are pointing.

Having said that, however, if calculating the angle of a line from the imaginary point to your destination (passing through your location) in order to draw a pointer towards your destination is what you want...simply subtract the (absolute) bearing of the destination from the absolute bearing of the imaginary object and ignore a negation (if present). e.g., NW - SE is 315 - 135 = 180 so draw the pointer to point at the bottom of the screen indicating 'behind you'.

EDIT: I got the Maths slightly wrong...subtract the smaller of the bearings from the larger then subtract the result from 360 to get the angle in which to draw the pointer on the screen.

Collision resolution in Java HashMap

There is no collision in your example. You use the same key, so the old value gets replaced with the new one. Now, if you used two keys that map to the same hash code, then you'd have a collision. But even in that case, HashMap would replace your value! If you want the values to be chained in case of a collision, you have to do it yourself, e.g. by using a list as a value.

How do I find the version of Apache running without access to the command line?

Telnet to the host at port 80.

Type:

get / http1.1
::enter::
::enter::

It is kind of an HTTP request, but it's not valid so the 500 error it gives you will probably give you the information you want. The blank lines at the end are important otherwise it will just seem to hang.

Parse usable Street Address, City, State, Zip from a string

This won't solve your problem, but if you only needed lat/long data for these addresses, the Google Maps API will parse non-formatted addresses pretty well.

How to compare two object variables in EL expression language?

In Expression Language you can just use the == or eq operator to compare object values. Behind the scenes they will actually use the Object#equals(). This way is done so, because until with the current EL 2.1 version you cannot invoke methods with other signatures than standard getter (and setter) methods (in the upcoming EL 2.2 it would be possible).

So the particular line

<c:when test="${lang}.equals(${pageLang})">

should be written as (note that the whole expression is inside the { and })

<c:when test="${lang == pageLang}">

or, equivalently

<c:when test="${lang eq pageLang}">

Both are behind the scenes roughly interpreted as

jspContext.findAttribute("lang").equals(jspContext.findAttribute("pageLang"))

If you want to compare constant String values, then you need to quote it

<c:when test="${lang == 'en'}">

or, equivalently

<c:when test="${lang eq 'en'}">

which is behind the scenes roughly interpreted as

jspContext.findAttribute("lang").equals("en")

How to bind event listener for rendered elements in Angular 2?

HostListener should be the proper way to bind event into your component:

@Component({
  selector: 'your-element'
})

export class YourElement {
  @HostListener('click', ['$event']) onClick(event) {
     console.log('component is clicked');
     console.log(event);
  }
}

Socket transport "ssl" in PHP not enabled

I was having problem in Windows 7 with PHP 5.4.0 in command line, using Xampp 1.8.1 server. This is what i did:

  1. Rename php.ini-production to php.ini (in C:\xampp\php\ folder)
  2. Edit php.ini and uncomment extension_dir=ext.
  3. Also uncomment extension=php_openssl.dll.

After that it worked fine.

Setting size for icon in CSS

you can change the size of an icon using the font size rather than setting the height and width of an icon. Here is how you do it:

<i class="fa fa-minus-square-o" style="font-size: 0.73em;"></i>

There are 4 ways to specify the dimensions of the icon.

px : give fixed pixels to your icon

em : dimensions with respect to your current font. Say ur current font is 12px then 1.5em will be 18px (12px + 6px).

pt : stands for points. Mostly used in print media

% : percentage. Refers to the size of the icon based on its original size.

How to install gem from GitHub source?

If you install using bundler as suggested by gryzzly and the gem creates a binary then make sure you run it with bundle exec mygembinary as the gem is stored in a bundler directory which is not visible on the normal gem path.

How to get margin value of a div in plain JavaScript?

The properties on the style object are only the styles applied directly to the element (e.g., via a style attribute or in code). So .style.marginTop will only have something in it if you have something specifically assigned to that element (not assigned via a style sheet, etc.).

To get the current calculated style of the object, you use either the currentStyle property (Microsoft) or the getComputedStyle function (pretty much everyone else).

Example:

var p = document.getElementById("target");
var style = p.currentStyle || window.getComputedStyle(p);

display("Current marginTop: " + style.marginTop);

Fair warning: What you get back may not be in pixels. For instance, if I run the above on a p element in IE9, I get back "1em".

Live Copy | Source

Map vs Object in JavaScript

In addition to the other answers, I've found that Maps are more unwieldy and verbose to operate with than objects.

obj[key] += x
// vs.
map.set(map.get(key) + x)

This is important, because shorter code is faster to read, more directly expressive, and better kept in the programmer's head.

Another aspect: because set() returns the map, not the value, it's impossible to chain assignments.

foo = obj[key] = x;  // Does what you expect
foo = map.set(key, x)  // foo !== x; foo === map

Debugging maps is also more painful. Below, you can't actually see what keys are in the map. You'd have to write code to do that.

Good luck evaluating a Map Iterator

Objects can be evaluated by any IDE:

WebStorm evaluating an object

Why are interface variables static and final by default?

An Interface is contract between two parties that is invariant, carved in the stone, hence final. See Design by Contract.

How can I convince IE to simply display application/json rather than offer to download it?

If you are okay with just having IE open the JSON into a notepad, you can change your system's default program for .json files to Notepad.

To do this, create or find a .json file, right mouse click, and select "Open With" or "Choose Default Program."

This might come in handy if you by chance want to use Internet Explorer but your IT company wont let you edit your registry. Otherwise, I recommend the above answers.

Last segment of URL in jquery

You can do this with simple paths (w/0) querystrings etc.

Granted probably overly complex and probably not performant, but I wanted to use reduce for the fun of it.

  "/foo/bar/"
    .split(path.sep)
    .filter(x => x !== "")
    .reduce((_, part, i, arr) => {
      if (i == arr.length - 1) return part;
    }, "");
  1. Split the string on path separators.
  2. Filter out empty string path parts (this could happen with trailing slash in path).
  3. Reduce the array of path parts to the last one.

How to get value at a specific index of array In JavaScript?

You can just use []:

var valueAtIndex1 = myValues[1];

List comprehension vs map

Cases

  • Common case: Almost always, you will want to use a list comprehension in python because it will be more obvious what you're doing to novice programmers reading your code. (This does not apply to other languages, where other idioms may apply.) It will even be more obvious what you're doing to python programmers, since list comprehensions are the de-facto standard in python for iteration; they are expected.
  • Less-common case: However if you already have a function defined, it is often reasonable to use map, though it is considered 'unpythonic'. For example, map(sum, myLists) is more elegant/terse than [sum(x) for x in myLists]. You gain the elegance of not having to make up a dummy variable (e.g. sum(x) for x... or sum(_) for _... or sum(readableName) for readableName...) which you have to type twice, just to iterate. The same argument holds for filter and reduce and anything from the itertools module: if you already have a function handy, you could go ahead and do some functional programming. This gains readability in some situations, and loses it in others (e.g. novice programmers, multiple arguments)... but the readability of your code highly depends on your comments anyway.
  • Almost never: You may want to use the map function as a pure abstract function while doing functional programming, where you're mapping map, or currying map, or otherwise benefit from talking about map as a function. In Haskell for example, a functor interface called fmap generalizes mapping over any data structure. This is very uncommon in python because the python grammar compels you to use generator-style to talk about iteration; you can't generalize it easily. (This is sometimes good and sometimes bad.) You can probably come up with rare python examples where map(f, *lists) is a reasonable thing to do. The closest example I can come up with would be sumEach = partial(map,sum), which is a one-liner that is very roughly equivalent to:

def sumEach(myLists):
    return [sum(_) for _ in myLists]
  • Just using a for-loop: You can also of course just use a for-loop. While not as elegant from a functional-programming viewpoint, sometimes non-local variables make code clearer in imperative programming languages such as python, because people are very used to reading code that way. For-loops are also, generally, the most efficient when you are merely doing any complex operation that is not building a list like list-comprehensions and map are optimized for (e.g. summing, or making a tree, etc.) -- at least efficient in terms of memory (not necessarily in terms of time, where I'd expect at worst a constant factor, barring some rare pathological garbage-collection hiccuping).

"Pythonism"

I dislike the word "pythonic" because I don't find that pythonic is always elegant in my eyes. Nevertheless, map and filter and similar functions (like the very useful itertools module) are probably considered unpythonic in terms of style.

Laziness

In terms of efficiency, like most functional programming constructs, MAP CAN BE LAZY, and in fact is lazy in python. That means you can do this (in python3) and your computer will not run out of memory and lose all your unsaved data:

>>> map(str, range(10**100))
<map object at 0x2201d50>

Try doing that with a list comprehension:

>>> [str(n) for n in range(10**100)]
# DO NOT TRY THIS AT HOME OR YOU WILL BE SAD #

Do note that list comprehensions are also inherently lazy, but python has chosen to implement them as non-lazy. Nevertheless, python does support lazy list comprehensions in the form of generator expressions, as follows:

>>> (str(n) for n in range(10**100))
<generator object <genexpr> at 0xacbdef>

You can basically think of the [...] syntax as passing in a generator expression to the list constructor, like list(x for x in range(5)).

Brief contrived example

from operator import neg
print({x:x**2 for x in map(neg,range(5))})

print({x:x**2 for x in [-y for y in range(5)]})

print({x:x**2 for x in (-y for y in range(5))})

List comprehensions are non-lazy, so may require more memory (unless you use generator comprehensions). The square brackets [...] often make things obvious, especially when in a mess of parentheses. On the other hand, sometimes you end up being verbose like typing [x for x in.... As long as you keep your iterator variables short, list comprehensions are usually clearer if you don't indent your code. But you could always indent your code.

print(
    {x:x**2 for x in (-y for y in range(5))}
)

or break things up:

rangeNeg5 = (-y for y in range(5))
print(
    {x:x**2 for x in rangeNeg5}
)

Efficiency comparison for python3

map is now lazy:

% python3 -mtimeit -s 'xs=range(1000)' 'f=lambda x:x' 'z=map(f,xs)'
1000000 loops, best of 3: 0.336 usec per loop            ^^^^^^^^^

Therefore if you will not be using all your data, or do not know ahead of time how much data you need, map in python3 (and generator expressions in python2 or python3) will avoid calculating their values until the last moment necessary. Usually this will usually outweigh any overhead from using map. The downside is that this is very limited in python as opposed to most functional languages: you only get this benefit if you access your data left-to-right "in order", because python generator expressions can only be evaluated the order x[0], x[1], x[2], ....

However let's say that we have a pre-made function f we'd like to map, and we ignore the laziness of map by immediately forcing evaluation with list(...). We get some very interesting results:

% python3 -mtimeit -s 'xs=range(1000)' 'f=lambda x:x' 'z=list(map(f,xs))'                                                                                                                                                
10000 loops, best of 3: 165/124/135 usec per loop        ^^^^^^^^^^^^^^^
                    for list(<map object>)

% python3 -mtimeit -s 'xs=range(1000)' 'f=lambda x:x' 'z=[f(x) for x in xs]'                                                                                                                                      
10000 loops, best of 3: 181/118/123 usec per loop        ^^^^^^^^^^^^^^^^^^
                    for list(<generator>), probably optimized

% python3 -mtimeit -s 'xs=range(1000)' 'f=lambda x:x' 'z=list(f(x) for x in xs)'                                                                                                                                    
1000 loops, best of 3: 215/150/150 usec per loop         ^^^^^^^^^^^^^^^^^^^^^^
                    for list(<generator>)

In results are in the form AAA/BBB/CCC where A was performed with on a circa-2010 Intel workstation with python 3.?.?, and B and C were performed with a circa-2013 AMD workstation with python 3.2.1, with extremely different hardware. The result seems to be that map and list comprehensions are comparable in performance, which is most strongly affected by other random factors. The only thing we can tell seems to be that, oddly, while we expect list comprehensions [...] to perform better than generator expressions (...), map is ALSO more efficient that generator expressions (again assuming that all values are evaluated/used).

It is important to realize that these tests assume a very simple function (the identity function); however this is fine because if the function were complicated, then performance overhead would be negligible compared to other factors in the program. (It may still be interesting to test with other simple things like f=lambda x:x+x)

If you're skilled at reading python assembly, you can use the dis module to see if that's actually what's going on behind the scenes:

>>> listComp = compile('[f(x) for x in xs]', 'listComp', 'eval')
>>> dis.dis(listComp)
  1           0 LOAD_CONST               0 (<code object <listcomp> at 0x2511a48, file "listComp", line 1>) 
              3 MAKE_FUNCTION            0 
              6 LOAD_NAME                0 (xs) 
              9 GET_ITER             
             10 CALL_FUNCTION            1 
             13 RETURN_VALUE         
>>> listComp.co_consts
(<code object <listcomp> at 0x2511a48, file "listComp", line 1>,)
>>> dis.dis(listComp.co_consts[0])
  1           0 BUILD_LIST               0 
              3 LOAD_FAST                0 (.0) 
        >>    6 FOR_ITER                18 (to 27) 
              9 STORE_FAST               1 (x) 
             12 LOAD_GLOBAL              0 (f) 
             15 LOAD_FAST                1 (x) 
             18 CALL_FUNCTION            1 
             21 LIST_APPEND              2 
             24 JUMP_ABSOLUTE            6 
        >>   27 RETURN_VALUE

 

>>> listComp2 = compile('list(f(x) for x in xs)', 'listComp2', 'eval')
>>> dis.dis(listComp2)
  1           0 LOAD_NAME                0 (list) 
              3 LOAD_CONST               0 (<code object <genexpr> at 0x255bc68, file "listComp2", line 1>) 
              6 MAKE_FUNCTION            0 
              9 LOAD_NAME                1 (xs) 
             12 GET_ITER             
             13 CALL_FUNCTION            1 
             16 CALL_FUNCTION            1 
             19 RETURN_VALUE         
>>> listComp2.co_consts
(<code object <genexpr> at 0x255bc68, file "listComp2", line 1>,)
>>> dis.dis(listComp2.co_consts[0])
  1           0 LOAD_FAST                0 (.0) 
        >>    3 FOR_ITER                17 (to 23) 
              6 STORE_FAST               1 (x) 
              9 LOAD_GLOBAL              0 (f) 
             12 LOAD_FAST                1 (x) 
             15 CALL_FUNCTION            1 
             18 YIELD_VALUE          
             19 POP_TOP              
             20 JUMP_ABSOLUTE            3 
        >>   23 LOAD_CONST               0 (None) 
             26 RETURN_VALUE

 

>>> evalledMap = compile('list(map(f,xs))', 'evalledMap', 'eval')
>>> dis.dis(evalledMap)
  1           0 LOAD_NAME                0 (list) 
              3 LOAD_NAME                1 (map) 
              6 LOAD_NAME                2 (f) 
              9 LOAD_NAME                3 (xs) 
             12 CALL_FUNCTION            2 
             15 CALL_FUNCTION            1 
             18 RETURN_VALUE 

It seems it is better to use [...] syntax than list(...). Sadly the map class is a bit opaque to disassembly, but we can make due with our speed test.

Is there a workaround for ORA-01795: maximum number of expressions in a list is 1000 error?

There's also workaround doing disjunction of your array, worked for me as other solutions were hard to implement using some old framework.

select * from tableA where id = 1 or id = 2 or id = 3 ...

But for better perfo, I would use Nikolai Nechai's solution with unions, if possible.

Python try-else

try:
    statements # statements that can raise exceptions
except:
    statements # statements that will be executed to handle exceptions
else:
    statements # statements that will be executed if there is no exception

Example :

try:
    age=int(input('Enter your age: '))
except:
    print ('You have entered an invalid value.')
else:
    if age <= 21:
        print('You are not allowed to enter, you are too young.')
    else:
        print('Welcome, you are old enough.')

The Output :

>>> 
Enter your age: a
You have entered an invalid value.
>>> RESTART
>>> 
Enter your age: 25
Welcome, you are old enough.
>>>RESTART
>>> 
Enter your age: 13
You are not allowed to enter, you are too young.
>>>

Copied from : https://geek-university.com/python/the-try-except-else-statements/

Format date and time in a Windows batch script

set hourstr = %time:~0,2%
if "%time:~0,1%"==" " (set hourstr=0%time:~1,1%)
set datetimestr=%date:~0,4%%date:~5,2%%date:~8,2%-%hourstr%%time:~3,2%%time:~6,2%

sendKeys() in Selenium web driver

I believe Selenium now uses Key.TAB instead of Keys.TAB.

Target a css class inside another css class

I use div instead of tables and am able to target classes within the main class, as below:

CSS

.main {
    .width: 800px;
    .margin: 0 auto;
    .text-align: center;
}
.main .table {
    width: 80%;
}
.main .row {
   / ***something ***/
}
.main .column {
    font-size: 14px;
    display: inline-block;
}
.main .left {
    width: 140px;
    margin-right: 5px;
    font-size: 12px;
}
.main .right {
    width: auto;
    margin-right: 20px;
    color: #fff;
    font-size: 13px;
    font-weight: normal;
}

HTML

<div class="main">
    <div class="table">
        <div class="row">
            <div class="column left">Swing Over Bed</div>
            <div class="column right">650mm</div>
            <div class="column left">Swing In Gap</div>
            <div class="column right">800mm</div>
        </div>
    </div>
</div>

If you want to style a particular "cell" exclusively you can use another sub-class or the id of the div e.g:

.main #red { color: red; }

<div class="main">
    <div class="table">
        <div class="row">
            <div id="red" class="column left">Swing Over Bed</div>
            <div class="column right">650mm</div>
            <div class="column left">Swing In Gap</div>
            <div class="column right">800mm</div>
        </div>
    </div>
</div>

R Plotting confidence bands with ggplot

require(ggplot2)
require(nlme)

set.seed(101)
mp <-data.frame(year=1990:2010)
N <- nrow(mp)

mp <- within(mp,
         {
             wav <- rnorm(N)*cos(2*pi*year)+rnorm(N)*sin(2*pi*year)+5
             wow <- rnorm(N)*wav+rnorm(N)*wav^3
         })

m01 <- gls(wow~poly(wav,3), data=mp, correlation = corARMA(p=1))

Get fitted values (the same as m01$fitted)

fit <- predict(m01)

Normally we could use something like predict(...,se.fit=TRUE) to get the confidence intervals on the prediction, but gls doesn't provide this capability. We use a recipe similar to the one shown at http://glmm.wikidot.com/faq :

V <- vcov(m01)
X <- model.matrix(~poly(wav,3),data=mp)
se.fit <- sqrt(diag(X %*% V %*% t(X)))

Put together a "prediction frame":

predframe <- with(mp,data.frame(year,wav,
                                wow=fit,lwr=fit-1.96*se.fit,upr=fit+1.96*se.fit))

Now plot with geom_ribbon

(p1 <- ggplot(mp, aes(year, wow))+
    geom_point()+
    geom_line(data=predframe)+
    geom_ribbon(data=predframe,aes(ymin=lwr,ymax=upr),alpha=0.3))

year vs wow

It's easier to see that we got the right answer if we plot against wav rather than year:

(p2 <- ggplot(mp, aes(wav, wow))+
    geom_point()+
    geom_line(data=predframe)+
    geom_ribbon(data=predframe,aes(ymin=lwr,ymax=upr),alpha=0.3))

wav vs wow

It would be nice to do the predictions with more resolution, but it's a little tricky to do this with the results of poly() fits -- see ?makepredictcall.

A url resource that is a dot (%2E)

It is not possible. §2.3 says that "." is an unreserved character and that "URIs that differ in the replacement of an unreserved character with its corresponding percent-encoded US-ASCII octet are equivalent". Therefore, /%2E%2E/ is the same as /../, and that will get normalized away.

(This is a combination of an answer by bobince and a comment by slowpoison.)

Adding asterisk to required fields in Bootstrap 3

Use .form-group.required without the space.

.form-group.required .control-label:after {
  content:"*";
  color:red;
}

Edit:

For the checkbox you can use the pseudo class :not(). You add the required * after each label unless it is a checkbox

.form-group.required:not(.checkbox) .control-label:after, 
.form-group.required .text:after { /* change .text in whatever class of the text after the checkbox has */
   content:"*";
   color:red;
}

Note: not tested

You should use the .text class or target it otherwise probably, try this html:

<div class="form-group required">
   <label class="col-md-2 control-label">&#160;</label>
   <div class="col-md-4">
      <div class="checkbox">
         <label class='text'> <!-- use this class -->
            <input class="" id="id_tos" name="tos" required="required" type="checkbox" /> I have read and agree to the Terms of Service
         </label>
      </div>
   </div>
</div>

Ok third edit:

CSS back to what is was

.form-group.required .control-label:after { 
   content:"*";
   color:red;
}

HTML:

<div class="form-group required">
   <label class="col-md-2">&#160;</label> <!-- remove class control-label -->
   <div class="col-md-4">
      <div class="checkbox">
         <label class='control-label'> <!-- use this class as the red * will be after control-label -->
            <input class="" id="id_tos" name="tos" required="required" type="checkbox" /> I have read and agree to the Terms of Service
         </label>
      </div>
   </div>
</div>

replace all occurrences in a string

Brighams answer uses literal regexp.

Solution with a Regex object.

var regex = new RegExp('\n', 'g');
text = text.replace(regex, '<br />');

TRY IT HERE : JSFiddle Working Example

CFLAGS, CCFLAGS, CXXFLAGS - what exactly do these variables control?

As you noticed, these are Makefile {macros or variables}, not compiler options. They implement a set of conventions. (Macros is an old name for them, still used by some. GNU make doc calls them variables.)

The only reason that the names matter is the default make rules, visible via make -p, which use some of them.

If you write all your own rules, you get to pick all your own macro names.

In a vanilla gnu make, there's no such thing as CCFLAGS. There are CFLAGS, CPPFLAGS, and CXXFLAGS. CFLAGS for the C compiler, CXXFLAGS for C++, and CPPFLAGS for both.

Why is CPPFLAGS in both? Conventionally, it's the home of preprocessor flags (-D, -U) and both c and c++ use them. Now, the assumption that everyone wants the same define environment for c and c++ is perhaps questionable, but traditional.


P.S. As noted by James Moore, some projects use CPPFLAGS for flags to the C++ compiler, not flags to the C preprocessor. The Android NDK, for one huge example.

How do you make a div follow as you scroll?

the position:fixed; property should do the work, I used it on my Website and it worked fine. http://www.w3schools.com/css/css_positioning.asp

Put a Delay in Javascript

This thread has a good discussion and a useful solution:

function pause( iMilliseconds )
{
    var sDialogScript = 'window.setTimeout( function () { window.close(); }, ' + iMilliseconds + ');';
    window.showModalDialog('javascript:document.writeln ("<script>' + sDialogScript + '<' + '/script>")');
}

Unfortunately it appears that this doesn't work in some versions of IE, but the thread has many other worthy proposals if that proves to be a problem for you.

Iterate over each line in a string in PHP

Potential memory issues with strtok:

Since one of the suggested solutions uses strtok, unfortunately it doesn't point out a potential memory issue (though it claims to be memory efficient). When using strtok according to the manual, the:

Note that only the first call to strtok uses the string argument. Every subsequent call to strtok only needs the token to use, as it keeps track of where it is in the current string.

It does this by loading the file into memory. If you're using large files, you need to flush them if you're done looping through the file.

<?php
function process($str) {
    $line = strtok($str, PHP_EOL);

    /*do something with the first line here...*/

    while ($line !== FALSE) {
        // get the next line
        $line = strtok(PHP_EOL);

        /*do something with the rest of the lines here...*/

    }
    //the bit that frees up memory
    strtok('', '');
}

If you're only concerned with physical files (eg. datamining):

According to the manual, for the file upload part you can use the file command:

 //Create the array
 $lines = file( $some_file );

 foreach ( $lines as $line ) {
   //do something here.
 }

How to make a edittext box in a dialog

I know its too late to answer this question but for others who are searching for some thing similar to this here is a simple code of an alertbox with an edittext

AlertDialog.Builder alert = new AlertDialog.Builder(this); 

or

new AlertDialog.Builder(mContext, R.style.MyCustomDialogTheme);

if you want to change the theme of the dialog.

final EditText edittext = new EditText(ActivityContext);
alert.setMessage("Enter Your Message");
alert.setTitle("Enter Your Title");

alert.setView(edittext);

alert.setPositiveButton("Yes Option", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int whichButton) {
        //What ever you want to do with the value
        Editable YouEditTextValue = edittext.getText();
        //OR
        String YouEditTextValue = edittext.getText().toString();
    }
});

alert.setNegativeButton("No Option", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int whichButton) {
        // what ever you want to do with No option.
    }
});

alert.show();

max value of integer

In C range for __int32 is –2147483648 to 2147483647. See here for full ranges.

unsigned short 0 to 65535
signed short –32768 to 32767
unsigned long 0 to 4294967295
signed long –2147483648 to 2147483647

There are no guarantees that an 'int' will be 32 bits, if you want to use variables of a specific size, particularly when writing code that involves bit manipulations, you should use the 'Standard Integer Types'.

In Java

The int data type is a 32-bit signed two's complement integer. It has a minimum value of -2,147,483,648 and a maximum value of 2,147,483,647 (inclusive).

React Native: Getting the position of an element

I needed to find the position of an element inside a ListView and used this snippet that works kind of like .offset:

const UIManager = require('NativeModules').UIManager;
const handle = React.findNodeHandle(this.refs.myElement);
UIManager.measureLayoutRelativeToParent(
  handle, 
  (e) => {console.error(e)}, 
  (x, y, w, h) => {
    console.log('offset', x, y, w, h);
  });

This assumes I had a ref='myElement' on my component.

How do I clear the dropdownlist values on button click event using jQuery?

If you want to reset the selected options

$('select option:selected').removeAttr('selected');

If you actually want to remove the options (although I don't think you mean this).

$('select').empty();

Substitute select for the most appropriate selector in your case (this may be by id or by CSS class). Using as is will reset all <select> elements on the page

Java: Calculating the angle between two points in degrees

you could add the following:

public float getAngle(Point target) {
    float angle = (float) Math.toDegrees(Math.atan2(target.y - y, target.x - x));

    if(angle < 0){
        angle += 360;
    }

    return angle;
}

by the way, why do you want to not use a double here?

PHP not displaying errors even though display_errors = On

You also need to make sure you have your php.ini file include the following set or errors will go only to the log that is set by default or specified in the virtual host's configuration.

display_errors = On

The php.ini file is where base settings for all PHP on your server, however these can easily be overridden and altered any place in the PHP code and effect everything following that change. A good check is to add the display_errors directive to your php.ini file. If you don't see an error, but one is being logged, insert this at the top of the file causing the error:

ini_set('display_errors', 1);
error_reporting(E_ALL);

If this works then something earlier in your code is disabling error display.

How do I install a Python package with a .whl file?

On Windows you can't just upgrade using pip install --upgrade pip, because the pip.exe is in use and there would be an error replacing it. Instead, you should upgrade pip like this:

easy_install --upgrade pip

Then check the pip version:

pip --version

If it shows 6.x series, there is wheel support.

Only then, you can install a wheel package like this:

pip install your-package.whl

Java : Comparable vs Comparator

When your class implements Comparable, the compareTo method of the class is defining the "natural" ordering of that object. That method is contractually obligated (though not demanded) to be in line with other methods on that object, such as a 0 should always be returned for objects when the .equals() comparisons return true.

A Comparator is its own definition of how to compare two objects, and can be used to compare objects in a way that might not align with the natural ordering.

For example, Strings are generally compared alphabetically. Thus the "a".compareTo("b") would use alphabetical comparisons. If you wanted to compare Strings on length, you would need to write a custom comparator.

In short, there isn't much difference. They are both ends to similar means. In general implement comparable for natural order, (natural order definition is obviously open to interpretation), and write a comparator for other sorting or comparison needs.

How to configure CORS in a Spring Boot + Spring Security application?

You can finish this with only a Single Class, Just add this on your class path.

This one is enough for Spring Boot, Spring Security, nothing else. :

        @Component
        @Order(Ordered.HIGHEST_PRECEDENCE)
        public class MyCorsFilterConfig implements Filter {

            @Override
            public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
                final HttpServletResponse response = (HttpServletResponse) res;
                response.setHeader("Access-Control-Allow-Origin", "*");
                response.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE");
                response.setHeader("Access-Control-Allow-Headers", "Authorization, Content-Type, enctype");
                response.setHeader("Access-Control-Max-Age", "3600");
                if (HttpMethod.OPTIONS.name().equalsIgnoreCase(((HttpServletRequest) req).getMethod())) {
                    response.setStatus(HttpServletResponse.SC_OK);
                } else {
                    chain.doFilter(req, res);
                }
            }

            @Override
            public void destroy() {
            }

            @Override
            public void init(FilterConfig config) throws ServletException {
            }


        }

Refresh/reload the content in Div using jquery/ajax

I know the topic is old, but you can declare the Ajax as a variable, then use a function to call the variable on the desired content. Keep in mind you are calling what you have in the Ajax if you want a different elements from the Ajax you need to specify it.

Example:

Var infogen = $.ajax({'your query')};

$("#refresh").click(function(){
  infogen;
  console.log("to verify");
});    

Hope helps

if not try:

$("#refresh").click(function(){
      loca.tion.reload();
      console.log("to verify");
    });    

Execute CMD command from code

Argh :D not the fastest

Process.Start("notepad C:\test.txt");

Check if a row exists using old mysql_* API

This ought to do the trick: just limit the result to 1 row; if a row comes back the $lectureName is Assigned, otherwise it's Available.

function checkLectureStatus($lectureName)
{
    $con = connectvar();
    mysql_select_db("mydatabase", $con);
    $result = mysql_query(
        "SELECT * FROM preditors_assigned WHERE lecture_name='$lectureName' LIMIT 1");

    if(mysql_fetch_array($result) !== false)
        return 'Assigned';
    return 'Available';
}

Free easy way to draw graphs and charts in C++?

Cern's ROOT produces some pretty nice stuff, I use it to display Neural Network data a lot.

Show percent % instead of counts in charts of categorical variables

Here is a workaround for faceted data. (The accepted answer by @Andrew does not work in this case.) The idea is to calculate the percentage value using dplyr and then to use geom_col to create the plot.

library(ggplot2)
library(scales)
library(magrittr)
library(dplyr)

binwidth <- 30

mtcars.stats <- mtcars %>%
  group_by(cyl) %>%
  mutate(bin = cut(hp, breaks=seq(0,400, binwidth), 
               labels= seq(0+binwidth,400, binwidth)-(binwidth/2)),
         n = n()) %>%
  group_by(cyl, bin) %>%
  summarise(p = n()/n[1]) %>%
  ungroup() %>%
  mutate(bin = as.numeric(as.character(bin)))

ggplot(mtcars.stats, aes(x = bin, y= p)) +  
  geom_col() + 
  scale_y_continuous(labels = percent) +
  facet_grid(cyl~.)

This is the plot:

enter image description here

Rails 3: I want to list all paths defined in my rails application

rake routes | grep <specific resource name>

displays resource specific routes, if it is a pretty long list of routes.

jQuery send HTML data through POST

_x000D_
_x000D_
jQuery.post(post_url,{ content: "John" } )_x000D_
 .done(function( data ) {_x000D_
   _x000D_
   _x000D_
 });_x000D_
 
_x000D_
_x000D_
_x000D_

I used the technique what u have replied above, it works fine but my problem is i need to generate a pdf conent using john as text . I have been able to echo the passed data. but getting empty in when generating pdf uisng below content ples check

_x000D_
_x000D_
ob_start();_x000D_
        _x000D_
   include_once(JPATH_SITE .'/components/com_gaevents/pdfgenerator.php');_x000D_
   $content = ob_get_clean();_x000D_
   _x000D_
  _x000D_
  _x000D_
    $test = $_SESSION['content'] ;_x000D_
  _x000D_
   require_once(JPATH_SITE.'/html2pdf/html2pdf.class.php');_x000D_
            $html2pdf = new HTML2PDF('P', 'A4', 'en', true, 'UTF-8',0 );   _x000D_
    $html2pdf->setDefaultFont('Arial');_x000D_
    $html2pdf->WriteHTML($test);
_x000D_
_x000D_
_x000D_

Replacing NULL and empty string within Select statement

For an example data in your table such as combinations of

'', null and as well as actual value than if you want to only actual value and replace to '' and null value by # symbol than execute this query

SELECT Column_Name = (CASE WHEN (Column_Name IS NULL OR Column_Name = '') THEN '#' ELSE Column_Name END) FROM Table_Name

and another way you can use it but this is little bit lengthy and instead of this you can also use IsNull function but here only i am mentioning IIF function

SELECT IIF(Column_Name IS NULL, '#', Column_Name) FROM Table_Name  
SELECT IIF(Column_Name  = '', '#', Column_Name) FROM Table_Name  
-- and syntax of this query
SELECT IIF(Column_Name IS NULL, 'True Value', 'False Value') FROM Table_Name

Java multiline string

A quite efficient and platform independent solution would be using the system property for line separators and the StringBuilder class to build strings:

String separator = System.getProperty("line.separator");
String[] lines = {"Line 1", "Line 2" /*, ... */};

StringBuilder builder = new StringBuilder(lines[0]);
for (int i = 1; i < lines.length(); i++) {
    builder.append(separator).append(lines[i]);
}
String multiLine = builder.toString();

How do I space out the child elements of a StackPanel?

I improved on Elad Katz' answer.

  • Add LastItemMargin property to MarginSetter to specially handle the last item
  • Add Spacing attached property with Vertical and Horizontal properties that adds spacing between items in vertical and horizontal lists and eliminates any trailing margin at the end of the list

Source code in gist.

Example:

<StackPanel Orientation="Horizontal" foo:Spacing.Horizontal="5">
  <Button>Button 1</Button>
  <Button>Button 2</Button>
</StackPanel>

<StackPanel Orientation="Vertical" foo:Spacing.Vertical="5">
  <Button>Button 1</Button>
  <Button>Button 2</Button>
</StackPanel>

<!-- Same as vertical example above -->
<StackPanel Orientation="Vertical" foo:MarginSetter.Margin="0 0 0 5" foo:MarginSetter.LastItemMargin="0">
  <Button>Button 1</Button>
  <Button>Button 2</Button>
</StackPanel>

Querying a linked sql server

try Select * from openquery("aa-db-dev01",'Select * from users') ,the database connection should be defined in he linked server configuration

Using a RegEx to match IP addresses in Python

regex for ip v4:

^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$

otherwise you take not valid ip address like 999.999.999.999, 256.0.0.0 etc

“tag already exists in the remote" error after recreating the git tag

It seems that I'm late on this issue and/or it has already been answered, but, what could be done is: (in my case, I had only one tag locally so.. I deleted the old tag and retagged it with:

git tag -d v1.0
git tag -a v1.0 -m "My commit message"

Then:

git push --tags -f

That will update all tags on remote.

Could be dangerous! Use at own risk.

PHP - Get bool to echo false when false

Try converting your boolean to an integer?

 echo (int)$bool_val;

How to Convert Boolean to String

I'm not a fan of the accepted answer as it converts anything which evaluates to false to "false" no just boolean and vis-versa.

Anyway here's my O.T.T answer, it uses the var_export function.

var_export works with all variable types except resource, I have created a function which will perform a regular cast to string ((string)), a strict cast (var_export) and a type check, depending on the arguments provided..

if(!function_exists('to_string')){

    function to_string($var, $strict = false, $expectedtype = null){

        if(!func_num_args()){
            return trigger_error(__FUNCTION__ . '() expects at least 1 parameter, 0 given', E_USER_WARNING);
        }
        if($expectedtype !== null  && gettype($var) !== $expectedtype){
            return trigger_error(__FUNCTION__ . '() expects parameter 1 to be ' . $expectedtype .', ' . gettype($var) . ' given', E_USER_WARNING);
        }
        if(is_string($var)){
            return $var;
        }
        if($strict && !is_resource($var)){
            return var_export($var, true);
        }
        return (string) $var;
    }
}

if(!function_exists('bool_to_string')){

    function bool_to_string($var){
        return func_num_args() ? to_string($var, true, 'boolean') : to_string();        
    }
}

if(!function_exists('object_to_string')){

    function object_to_string($var){
        return func_num_args() ? to_string($var, true, 'object') : to_string();        
    }
}

if(!function_exists('array_to_string')){

    function array_to_string($var){
        return func_num_args() ? to_string($var, true, 'array') : to_string();        
    }
}

Scraping: SSL: CERTIFICATE_VERIFY_FAILED error for http://en.wikipedia.org

For anyone who is using anaconda, you would install the certifi package, see more at:

https://anaconda.org/anaconda/certifi

To install, type this line in your terminal:

conda install -c anaconda certifi

Frontend tool to manage H2 database

I use DbVisualizer a lot for H2-db administration.

There exists a free version:

https://www.dbvis.com/download/

Angular pass callback function to child component as @Input similar to AngularJS way

Use Observable pattern. You can put Observable value (not Subject) into Input parameter and manage it from parent component. You do not need callback function.

See example: https://stackoverflow.com/a/49662611/4604351

How can I upload fresh code at github?

Just to add on to the other answers, before i knew my way around git, i was looking for some way to upload existing code to a new github (or other git) repo. Here's the brief that would save time for newbs:-

Assuming you have your NEW empty github or other git repo ready:-

cd "/your/repo/dir"
git clone https://github.com/user_AKA_you/repoName # (creates /your/repo/dir/repoName)
cp "/all/your/existing/code/*" "/your/repo/dir/repoName/"
git add -A
git commit -m "initial commit"
git push origin master

Alternatively if you have an existing local git repo

cd "/your/repo/dir/repoName"
#add your remote github or other git repo
git remote set-url origin https://github.com/user_AKA_you/your_repoName
git commit -m "new origin commit"
git push origin master

Validate a username and password against Active Directory?

Unfortunately there is no "simple" way to check a users credentials on AD.

With every method presented so far, you may get a false-negative: A user's creds will be valid, however AD will return false under certain circumstances:

  • User is required to Change Password at Next Logon.
  • User's password has expired.

ActiveDirectory will not allow you to use LDAP to determine if a password is invalid due to the fact that a user must change password or if their password has expired.

To determine password change or password expired, you may call Win32:LogonUser(), and check the windows error code for the following 2 constants:

  • ERROR_PASSWORD_MUST_CHANGE = 1907
  • ERROR_PASSWORD_EXPIRED = 1330

Common Header / Footer with static HTML

The simplest way to do that is using plain HTML.

You can use one of these ways:

<embed type="text/html" src="header.html">

or:

<object name="foo" type="text/html" data="header.html"></object>

The origin server did not find a current representation for the target resource or is not willing to disclose that one exists. on deploying to tomcat

This issue can even occur when you try to run your project from controller page. Run your project from the jsp page. Go to your jsp page; right-click->Run As->Run on Server. I faced the same issue.I was running my project from the controller page. Run your project from jsp page.

Get connection status on Socket.io client

You can check whether the connection was lost or not by using this function:-

var socket = io( /**connection**/ );
socket.on('disconnect', function(){
//Your Code Here
});

Hope it will help you.

Get Month name from month number

You can get this in following way,

DateTimeFormatInfo mfi = new DateTimeFormatInfo();
string strMonthName = mfi.GetMonthName(8).ToString(); //August

Now, get first three characters

string shortMonthName = strMonthName.Substring(0, 3); //Aug

Fixed Table Cell Width

table td 
{
  table-layout:fixed;
  width:20px;
  overflow:hidden;
  word-wrap:break-word;
}

How can I use inverse or negative wildcards when pattern matching in a unix/linux shell?

You can also use a pretty simple for loop:

for f in `find . -not -name "*Music*"`
do
    cp $f /target/dir
done

Why is this error, 'Sequence contains no elements', happening?

Check again. Use debugger if must. My guess is that for some item in userResponseDetails this query finds no elements:

.Where(y => y.ResponseId.Equals(item.ResponseId))

so you can't call

.First()

on it. Maybe try

.FirstOrDefault()

if it solves the issue.

Do NOT return NULL value! This is purely so that you can see and diagnose where problem is. Handle these cases properly.

How to URL encode a string in Ruby

I was originally trying to escape special characters in a file name only, not on the path, from a full URL string.

ERB::Util.url_encode didn't work for my use:

helper.send(:url_encode, "http://example.com/?a=\11\15")
# => "http%3A%2F%2Fexample.com%2F%3Fa%3D%09%0D"

Based on two answers in "Why is URI.escape() marked as obsolete and where is this REGEXP::UNSAFE constant?", it looks like URI::RFC2396_Parser#escape is better than using URI::Escape#escape. However, they both are behaving the same to me:

URI.escape("http://example.com/?a=\11\15")
# => "http://example.com/?a=%09%0D"
URI::Parser.new.escape("http://example.com/?a=\11\15")
# => "http://example.com/?a=%09%0D"

how to pass command line arguments to main method dynamically

If you want to launch VM by sending arguments, you should send VM arguments and not Program arguments.

Program arguments are arguments that are passed to your application, which are accessible via the "args" String array parameter of your main method. VM arguments are arguments such as System properties that are passed to the JavaSW interpreter. The Debug configuration above is essentially equivalent to:

java -DsysProp1=sp1 -DsysProp2=sp2 test.ArgsTest pro1 pro2 pro3

The VM arguments go after the call to your Java interpreter (ie, 'java') and before the Java class. Program arguments go after your Java class.

Consider a program ArgsTest.java:

package test;

import java.io.IOException;

    public class ArgsTest {

        public static void main(String[] args) throws IOException {

            System.out.println("Program Arguments:");
            for (String arg : args) {
                System.out.println("\t" + arg);
            }

            System.out.println("System Properties from VM Arguments");
            String sysProp1 = "sysProp1";
            System.out.println("\tName:" + sysProp1 + ", Value:" + System.getProperty(sysProp1));
            String sysProp2 = "sysProp2";
            System.out.println("\tName:" + sysProp2 + ", Value:" + System.getProperty(sysProp2));

        }
    }

If given input as,

java -DsysProp1=sp1 -DsysProp2=sp2 test.ArgsTest pro1 pro2 pro3 

in the commandline, in project bin folder would give the following result:

Program Arguments:
  pro1
  pro2
  pro3
System Properties from VM Arguments
  Name:sysProp1, Value:sp1
  Name:sysProp2, Value:sp2

PHP compare two arrays and get the matched values not the difference

Simple, use array_intersect() instead:

$result = array_intersect($array1, $array2);

AWK to print field $2 first, then field $1

A couple of general tips (besides the DOS line ending issue):

cat is for concatenating files, it's not the only tool that can read files! If a command doesn't read files then use redirection like command < file.

You can set the field separator with the -F option so instead of:

cat foo | awk 'BEGIN{FS="|"} {print $2 " " $1}' 

Try:

awk -F'|' '{print $2" "$1}' foo 

This will output:

com.emailclient.account [email protected]
com.socialsite.auth.accoun [email protected]

To get the desired output you could do a variety of things. I'd probably split() the second field:

awk -F'|' '{split($2,a,".");print a[2]" "$1}' file
emailclient [email protected]
socialsite [email protected]

Finally to get the first character converted to uppercase is a bit of a pain in awk as you don't have a nice built in ucfirst() function:

awk -F'|' '{split($2,a,".");print toupper(substr(a[2],1,1)) substr(a[2],2),$1}' file
Emailclient [email protected]
Socialsite [email protected]

If you want something more concise (although you give up a sub-process) you could do:

awk -F'|' '{split($2,a,".");print a[2]" "$1}' file | sed 's/^./\U&/'
Emailclient [email protected]
Socialsite [email protected]

How to parse JSON and access results

Try:

$result = curl_exec($cURL);
$result = json_decode($result,true);

Now you can access MessageID from $result['MessageID'].

As for the database, it's simply using a query like so:

INSERT INTO `tableName`(`Cancelled`,`Queued`,`SMSError`,`SMSIncommingMessage`,`Sent`,`SentDateTime`) VALUES('?','?','?','?','?');

Prepared.

Offset a background image from the right using CSS

If you would like to use this for adding arrows/other icons to a button for example then you could use css pseudo-elements?

If it's really a background-image for the whole button, I tend to incorporate the spacing into the image, and just use

background-position: right 0;

But if I have to add for example a designed arrow to a button, I tend to have this html:

<a href="[url]" class="read-more">Read more</a>

And tend to do the following with CSS:

.read-more{
    position: relative;
    padding: 6px 15px 6px 35px;//to create space on the right
    font-size: 13px;
    font-family: Arial;
}

.read-more:after{
    content: '';
    display: block;
    width: 10px;
    height: 15px;
    background-image: url('../images/btn-white-arrow-right.png');
    position: absolute;
    right: 12px;
    top: 10px;
}

By using the :after selector, I add a element using CSS just to contain this small icon. You could do the same by just adding a span or <i> element inside the a-element. But I think this is a cleaner way of adding icons to buttons and it is cross-browser supported.

you can check out the fiddle here: http://codepen.io/anon/pen/PNzYzZ

R error "sum not meaningful for factors"

The error comes when you try to call sum(x) and x is a factor.

What that means is that one of your columns, though they look like numbers are actually factors (what you are seeing is the text representation)

simple fix, convert to numeric. However, it needs an intermeidate step of converting to character first. Use the following:

family[, 1] <- as.numeric(as.character( family[, 1] ))
family[, 3] <- as.numeric(as.character( family[, 3] ))

For a detailed explanation of why the intermediate as.character step is needed, take a look at this question: How to convert a factor to integer\numeric without loss of information?

How can I import a database with MySQL from terminal?

Before running the commands on the terminal you have to make sure that you have MySQL installed on your terminal.

You can use the following command to install it:

sudo apt-get update
sudo apt-get install mysql-server

Refrence here.

After that you can use the following commands to import a database:

mysql -u <username> -p <databasename> < <filename.sql>

How do I get a Date without time in Java?

The most straigthforward way that makes full use of the huge TimeZone Database of Java and is correct:

long currentTime = new Date().getTime();
long dateOnly = currentTime + TimeZone.getDefault().getOffset(currentTime);

Convert wchar_t to char

assert is for ensuring that something is true in a debug mode, without it having any effect in a release build. Better to use an if statement and have an alternate plan for characters that are outside the range, unless the only way to get characters outside the range is through a program bug.

Also, depending on your character encoding, you might find a difference between the Unicode characters 0x80 through 0xff and their char version.

Difference between JSONObject and JSONArray

The difference is the same as a (Hash)Map vs List.

JSONObject:

  • Contains named values (key->value pairs, tuples or whatever you want to call them)
    • like {ID : 1}
  • Order of elements is not important
    • a JSONObject of {id: 1, name: 'B'} is equal to {name: 'B', id: 1}.

JSONArray:

  • Contains only series values
    • like [1, 'value']
  • Order of values is important
    • array of [1,'value'] is not the same as ['value',1]

Example

JSON Object --> { "":""}

JSON Array --> [ , , , ]

{"employees":[
    {"firstName":"John", "lastName":"Doe"},
    {"firstName":"Anna", "lastName":"Smith"},
    {"firstName":"Peter", "lastName":"Jones"}
]}

How to find the Windows version from the PowerShell command line

I am refining one of the answers

I reached this question while trying to match the output from winver.exe:

Version 1607 (OS Build 14393.351)

I was able to extract the build string with:

,((Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion" -Name BuildLabEx).BuildLabEx -split '\.') | % {  $_[0..1] -join '.' }  

Result: 14393.351

Updated: Here is a slightly simplified script using regex

(Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion").BuildLabEx -match '^[0-9]+\.[0-9]+' |  % { $matches.Values }

How to use OpenFileDialog to select a folder?

Here is a pure C# version that should work with all versions of .NET (including .NET Core, .NET 5, WPF, Winforms, etc.) and uses Windows Vista (and higher) IFileDialog interface with the FOS_PICKFOLDERS options so it has the nice folder picker Windows standard UI. I have also added WPF's Window type support but this is optional.

usage:

var dlg = new FolderPicker();
dlg.InputPath = @"c:\windows\system32";
if (dlg.ShowDialog() == true)
{
    MessageBox.Show(dlg.ResultPath);
}

code:

    using System;
    using System.Diagnostics;
    using System.Runtime.InteropServices;
    using System.Runtime.InteropServices.ComTypes;
    using System.Windows; // for WPF support
    using System.Windows.Interop;  // for WPF support

    public class FolderPicker
    {
        public virtual string ResultPath { get; protected set; }
        public virtual string ResultName { get; protected set; }
        public virtual string InputPath { get; set; }
        public virtual bool ForceFileSystem { get; set; }
        public virtual string Title { get; set; }
        public virtual string OkButtonLabel { get; set; }
        public virtual string FileNameLabel { get; set; }

        protected virtual int SetOptions(int options)
        {
            if (ForceFileSystem)
            {
                options |= (int)FOS.FOS_FORCEFILESYSTEM;
            }
            return options;
        }

        // for WPF support
        public bool? ShowDialog(Window owner = null, bool throwOnError = false)
        {
            owner ??= Application.Current.MainWindow;
            return ShowDialog(owner != null ? new WindowInteropHelper(owner).Handle : IntPtr.Zero, throwOnError);
        }

        // for all .NET
        public virtual bool? ShowDialog(IntPtr owner, bool throwOnError = false)
        {
            var dialog = (IFileOpenDialog)new FileOpenDialog();
            if (!string.IsNullOrEmpty(InputPath))
            {
                if (CheckHr(SHCreateItemFromParsingName(InputPath, null, typeof(IShellItem).GUID, out var item), throwOnError) != 0)
                    return null;

                dialog.SetFolder(item);
            }

            var options = FOS.FOS_PICKFOLDERS;
            options = (FOS)SetOptions((int)options);
            dialog.SetOptions(options);

            if (Title != null)
            {
                dialog.SetTitle(Title);
            }

            if (OkButtonLabel != null)
            {
                dialog.SetOkButtonLabel(OkButtonLabel);
            }

            if (FileNameLabel != null)
            {
                dialog.SetFileName(FileNameLabel);
            }

            if (owner == IntPtr.Zero)
            {
                owner = Process.GetCurrentProcess().MainWindowHandle;
                if (owner == IntPtr.Zero)
                {
                    owner = GetDesktopWindow();
                }
            }

            var hr = dialog.Show(owner);
            if (hr == ERROR_CANCELLED)
                return null;

            if (CheckHr(hr, throwOnError) != 0)
                return null;

            if (CheckHr(dialog.GetResult(out var result), throwOnError) != 0)
                return null;

            if (CheckHr(result.GetDisplayName(SIGDN.SIGDN_DESKTOPABSOLUTEPARSING, out var path), throwOnError) != 0)
                return null;

            ResultPath = path;

            if (CheckHr(result.GetDisplayName(SIGDN.SIGDN_DESKTOPABSOLUTEEDITING, out path), false) == 0)
            {
                ResultName = path;
            }
            return true;
        }

        private static int CheckHr(int hr, bool throwOnError)
        {
            if (hr != 0)
            {
                if (throwOnError)
                    Marshal.ThrowExceptionForHR(hr);
            }
            return hr;
        }

        [DllImport("shell32")]
        private static extern int SHCreateItemFromParsingName([MarshalAs(UnmanagedType.LPWStr)] string pszPath, IBindCtx pbc, [MarshalAs(UnmanagedType.LPStruct)] Guid riid, out IShellItem ppv);

        [DllImport("user32")]
        private static extern IntPtr GetDesktopWindow();

#pragma warning disable IDE1006 // Naming Styles
        private const int ERROR_CANCELLED = unchecked((int)0x800704C7);
#pragma warning restore IDE1006 // Naming Styles

        [ComImport, Guid("DC1C5A9C-E88A-4dde-A5A1-60F82A20AEF7")] // CLSID_FileOpenDialog
        private class FileOpenDialog
        {
        }

        [ComImport, Guid("42f85136-db7e-439c-85f1-e4075d135fc8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        private interface IFileOpenDialog
        {
            [PreserveSig] int Show(IntPtr parent); // IModalWindow
            [PreserveSig] int SetFileTypes();  // not fully defined
            [PreserveSig] int SetFileTypeIndex(int iFileType);
            [PreserveSig] int GetFileTypeIndex(out int piFileType);
            [PreserveSig] int Advise(); // not fully defined
            [PreserveSig] int Unadvise();
            [PreserveSig] int SetOptions(FOS fos);
            [PreserveSig] int GetOptions(out FOS pfos);
            [PreserveSig] int SetDefaultFolder(IShellItem psi);
            [PreserveSig] int SetFolder(IShellItem psi);
            [PreserveSig] int GetFolder(out IShellItem ppsi);
            [PreserveSig] int GetCurrentSelection(out IShellItem ppsi);
            [PreserveSig] int SetFileName([MarshalAs(UnmanagedType.LPWStr)] string pszName);
            [PreserveSig] int GetFileName([MarshalAs(UnmanagedType.LPWStr)] out string pszName);
            [PreserveSig] int SetTitle([MarshalAs(UnmanagedType.LPWStr)] string pszTitle);
            [PreserveSig] int SetOkButtonLabel([MarshalAs(UnmanagedType.LPWStr)] string pszText);
            [PreserveSig] int SetFileNameLabel([MarshalAs(UnmanagedType.LPWStr)] string pszLabel);
            [PreserveSig] int GetResult(out IShellItem ppsi);
            [PreserveSig] int AddPlace(IShellItem psi, int alignment);
            [PreserveSig] int SetDefaultExtension([MarshalAs(UnmanagedType.LPWStr)] string pszDefaultExtension);
            [PreserveSig] int Close(int hr);
            [PreserveSig] int SetClientGuid();  // not fully defined
            [PreserveSig] int ClearClientData();
            [PreserveSig] int SetFilter([MarshalAs(UnmanagedType.IUnknown)] object pFilter);
            [PreserveSig] int GetResults([MarshalAs(UnmanagedType.IUnknown)] out object ppenum);
            [PreserveSig] int GetSelectedItems([MarshalAs(UnmanagedType.IUnknown)] out object ppsai);
        }

        [ComImport, Guid("43826D1E-E718-42EE-BC55-A1E261C37BFE"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        private interface IShellItem
        {
            [PreserveSig] int BindToHandler(); // not fully defined
            [PreserveSig] int GetParent(); // not fully defined
            [PreserveSig] int GetDisplayName(SIGDN sigdnName, [MarshalAs(UnmanagedType.LPWStr)] out string ppszName);
            [PreserveSig] int GetAttributes();  // not fully defined
            [PreserveSig] int Compare();  // not fully defined
        }

        #pragma warning disable CA1712 // Do not prefix enum values with type name
        private enum SIGDN : uint
        {
            SIGDN_DESKTOPABSOLUTEEDITING = 0x8004c000,
            SIGDN_DESKTOPABSOLUTEPARSING = 0x80028000,
            SIGDN_FILESYSPATH = 0x80058000,
            SIGDN_NORMALDISPLAY = 0,
            SIGDN_PARENTRELATIVE = 0x80080001,
            SIGDN_PARENTRELATIVEEDITING = 0x80031001,
            SIGDN_PARENTRELATIVEFORADDRESSBAR = 0x8007c001,
            SIGDN_PARENTRELATIVEPARSING = 0x80018001,
            SIGDN_URL = 0x80068000
        }

        [Flags]
        private enum FOS
        {
            FOS_OVERWRITEPROMPT = 0x2,
            FOS_STRICTFILETYPES = 0x4,
            FOS_NOCHANGEDIR = 0x8,
            FOS_PICKFOLDERS = 0x20,
            FOS_FORCEFILESYSTEM = 0x40,
            FOS_ALLNONSTORAGEITEMS = 0x80,
            FOS_NOVALIDATE = 0x100,
            FOS_ALLOWMULTISELECT = 0x200,
            FOS_PATHMUSTEXIST = 0x800,
            FOS_FILEMUSTEXIST = 0x1000,
            FOS_CREATEPROMPT = 0x2000,
            FOS_SHAREAWARE = 0x4000,
            FOS_NOREADONLYRETURN = 0x8000,
            FOS_NOTESTFILECREATE = 0x10000,
            FOS_HIDEMRUPLACES = 0x20000,
            FOS_HIDEPINNEDPLACES = 0x40000,
            FOS_NODEREFERENCELINKS = 0x100000,
            FOS_OKBUTTONNEEDSINTERACTION = 0x200000,
            FOS_DONTADDTORECENT = 0x2000000,
            FOS_FORCESHOWHIDDEN = 0x10000000,
            FOS_DEFAULTNOMINIMODE = 0x20000000,
            FOS_FORCEPREVIEWPANEON = 0x40000000,
            FOS_SUPPORTSTREAMABLEITEMS = unchecked((int)0x80000000)
        }
        #pragma warning restore CA1712 // Do not prefix enum values with type name
    }

result:

enter image description here

How to align the text middle of BUTTON

I think you can use Padding like: Hope this one can help you.

.loginButton {
    background:url(images/loginBtn-center.jpg) repeat-x;
    width:175px;
    height:65px;
    margin:20px auto;
    border-radius:10px;
    -webkit-border-radius:10px;
    box-shadow:0 1px 2px #5e5d5b;
    <!--Using padding to align text in box or image-->
    padding: 3px 2px;
}

python-How to set global variables in Flask?

With:

global index_add_counter

You are not defining, just declaring so it's like saying there is a global index_add_counter variable elsewhere, and not create a global called index_add_counter. As you name don't exists, Python is telling you it can not import that name. So you need to simply remove the global keyword and initialize your variable:

index_add_counter = 0

Now you can import it with:

from app import index_add_counter

The construction:

global index_add_counter

is used inside modules' definitions to force the interpreter to look for that name in the modules' scope, not in the definition one:

index_add_counter = 0
def test():
  global index_add_counter # means: in this scope, use the global name
  print(index_add_counter)

What's the difference between "Solutions Architect" and "Applications Architect"?

An 'architect' is the title given to someone who can design multiple layers of applications that work together well at a high level. Anything that gets into a generic type of 'architect' without a specific type of technology (i.e. "Solutions", "Applications", "Business", etc) is marketing speak.

How to extract the hostname portion of a URL in JavaScript

There are two ways. The first is a variant of another answer here, but this one accounts for non-default ports:

function getRootUrl() {
  var defaultPorts = {"http:":80,"https:":443};

  return window.location.protocol + "//" + window.location.hostname
   + (((window.location.port)
    && (window.location.port != defaultPorts[window.location.protocol]))
    ? (":"+window.location.port) : "");
}

But I prefer this simpler method (which works with any URI string):

function getRootUrl(url) {
  return url.toString().replace(/^(.*\/\/[^\/?#]*).*$/,"$1");
}

How to drop a list of rows from Pandas dataframe?

If the DataFrame is huge, and the number of rows to drop is large as well, then simple drop by index df.drop(df.index[]) takes too much time.

In my case, I have a multi-indexed DataFrame of floats with 100M rows x 3 cols, and I need to remove 10k rows from it. The fastest method I found is, quite counterintuitively, to take the remaining rows.

Let indexes_to_drop be an array of positional indexes to drop ([1, 2, 4] in the question).

indexes_to_keep = set(range(df.shape[0])) - set(indexes_to_drop)
df_sliced = df.take(list(indexes_to_keep))

In my case this took 20.5s, while the simple df.drop took 5min 27s and consumed a lot of memory. The resulting DataFrame is the same.

Angularjs ng-model doesn't work inside ng-if

The ng-if directive, like other directives creates a child scope. See the script below (or this jsfiddle)

_x000D_
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.0rc1/angular.min.js"></script>_x000D_
_x000D_
<script>_x000D_
    function main($scope) {_x000D_
        $scope.testa = false;_x000D_
        $scope.testb = false;_x000D_
        $scope.testc = false;_x000D_
        $scope.obj = {test: false};_x000D_
    }_x000D_
</script>_x000D_
_x000D_
<div ng-app >_x000D_
    <div ng-controller="main">_x000D_
        _x000D_
        Test A: {{testa}}<br />_x000D_
        Test B: {{testb}}<br />_x000D_
        Test C: {{testc}}<br />_x000D_
        {{obj.test}}_x000D_
        _x000D_
        <div>_x000D_
            testa (without ng-if): <input type="checkbox" ng-model="testa" />_x000D_
        </div>_x000D_
        <div ng-if="!testa">_x000D_
            testb (with ng-if): <input type="checkbox" ng-model="testb" /> {{testb}}_x000D_
        </div>_x000D_
        <div ng-if="!someothervar">_x000D_
            testc (with ng-if): <input type="checkbox" ng-model="testc" />_x000D_
        </div>_x000D_
        <div ng-if="!someothervar">_x000D_
            object (with ng-if): <input type="checkbox" ng-model="obj.test" />_x000D_
        </div>_x000D_
        _x000D_
    </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

So, your checkbox changes the testb inside of the child scope, but not the outer parent scope.

Note, that if you want to modify the data in the parent scope, you'll need to modify the internal properties of an object like in the last div that I added.

Request is not available in this context

I was able to workaround/hack this problem by moving in to "Classic" mode from "integrated" mode.

How to push both key and value into an Array in Jquery

arr[title] = link;

You're not pushing into the array, you're setting the element with the key title to the value link. As such your array should be an object.

Make the console wait for a user input to close

I've put in what x4u said. Eclipse wanted a try catch block around it so I let it generate it for me.

try {
        System.in.read();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

It can probably have all sorts of bells and whistles on it but I think for beginners that want a command line window not quitting this should be fine.

Also I don't know how common this is (this is my first time making jar files), but it wouldn't run by itself, only via a bat file.

java.exe -jar mylibrary.jar

The above is what the bat file had in the same folder. Seems to be an install issue.

Eclipse tutorial came from: http://eclipsetutorial.sourceforge.net/index.html

Some of the answer also came from: Oracle Thread

SSH to Vagrant box in Windows?

Another option using git binaries:

  1. Install git: http://git-scm.com/download/win
  2. Start Menu > cmd (shift+enter to go as Administrator)
  3. set PATH=%PATH%;C:\Program Files\Git\usr\bin
  4. vagrant ssh

Hope this helps :)

Just a bonus after months using that on Windows: use Console instead of the Win terminal, so you can always open a new terminal tab with PATH set (configure it on options)

TypeError: You provided an invalid object where a stream was expected. You can provide an Observable, Promise, Array, or Iterable

this error happened with me when i am using interceptor you have to do this in your interceptor

return next.handle(request).map(event => {
        if (event instanceof HttpResponse) {

        }
        return event;
    },
      catchError((error: HttpErrorResponse) => {
        if (error.status === 401 || error.status === 400) {
          // some logic

        }

How to include route handlers in multiple files in Express?

If you want to put the routes in a separate file, for example routes.js, you can create the routes.js file in this way:

module.exports = function(app){

    app.get('/login', function(req, res){
        res.render('login', {
            title: 'Express Login'
        });
    });

    //other routes..
}

And then you can require it from app.js passing the app object in this way:

require('./routes')(app);

Have also a look at these examples

https://github.com/visionmedia/express/tree/master/examples/route-separation

ASP.NET MVC on IIS 7.5

Adding another solution for this issue.

in my Global.asax.cs file I had disabled attempted php files from being consumed by the MVC pipeline using the following:

routes.IgnoreRoute( "{*php}" );

I had done these previously in a MVC2 project and it worked fine, but doing this in my MVC 3 app caused the issue reported above.

phonegap open link in browser

At last this post helps me on iOS: http://www.excellentwebworld.com/phonegap-open-a-link-in-safari-or-external-browser/.

Open "CDVwebviewDelegate.m" file and search "shouldStartLoadWithRequest", then add this code to the beginning of the function:

if([[NSString stringWithFormat:@"%@",request.URL] rangeOfString:@"file"].location== NSNotFound) {
    [[UIApplication sharedApplication] openURL:[request URL]];
    return NO;
}

While using navigator.app.loadUrl("http://google.com", {openExternal : true}); for Android is OK.

Via Cordova 3.3.0.

How to insert an object in an ArrayList at a specific position

Actually the way to do it on your specific question is arrayList.add(1,"INSERTED ELEMENT"); where 1 is the position

Compile/run assembler in Linux?

For Ubuntu 18.04 installnasm . Open the terminal and type:

sudo apt install as31 nasm

nasm docs

For compiling and running:

nasm -f elf64 example.asm # assemble the program  
ld -s -o example example.o # link the object file nasm produced into an executable file  
./example # example is an executable file

How do I iterate through the files in a directory in Java?

You can also misuse File.list(FilenameFilter) (and variants) for file traversal. Short code and works in early java versions, e.g:

// list files in dir
new File(dir).list(new FilenameFilter() {
    public boolean accept(File dir, String name) {
        String file = dir.getAbsolutePath() + File.separator + name;
        System.out.println(file);
        return false;
    }
});

Background Image for Select (dropdown) does not work in Chrome

you can use the below css styles for all browsers except Firefox 30

select {
  background: url(dropdown_arw.png) no-repeat right center;
  appearance: none;
  -moz-appearance: none;
  -webkit-appearance: none;
  width: 90px;
  text-indent: 0.01px;
  text-overflow: "";
}

demo page - http://kvijayanand.in/jquery-plugin/test.html

Updated

here is solution for Firefox 30. little trick for custom select elements in firefox :-moz-any() css pseudo class.

http://blog.kvijayanand.in/customize-select-arrow-css/

RadioGroup: How to check programmatically

try this if you want your radio button to be checked based on value of some variable e.g. "genderStr" then you can use following code snippet

    if(genderStr.equals("Male"))
       genderRG.check(R.id.maleRB);
    else 
       genderRG.check(R.id.femaleRB);

Sequel Pro Alternative for Windows

Toad for MySQL by Quest is free for non-commercial use. I really like the interface and it's quite powerful if you have several databases to work with (for example development, test and production servers).

From the website:

Toad® for MySQL is a freeware development tool that enables you to rapidly create and execute queries, automate database object management, and develop SQL code more efficiently. It provides utilities to compare, extract, and search for objects; manage projects; import/export data; and administer the database. Toad for MySQL dramatically increases productivity and provides access to an active user community.

Tools to search for strings inside files without indexing

Original Answer

Windows Grep does this really well.

Edit: Windows Grep is no longer being maintained or made available by the developer. An alternate download link is here: Windows Grep - alternate

Current Answer

Visual Studio Code has excellent search and replace capabilities across files. It is extremely fast, supports regex and live preview before replacement.

enter image description here

org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8005]]A child container failed during start

Go to the task manager, kill the java processes and turn the server back on. should work fine.

Flutter Circle Design

More efficient way

I suggest you to draw a circle with CustomPainter. It's very easy and way more efficient than creating a bunch of widgets/masks:

Flutter draw circle

/// Draws a circle if placed into a square widget.
class CirclePainter extends CustomPainter {
  final _paint = Paint()
    ..color = Colors.red
    ..strokeWidth = 2
    // Use [PaintingStyle.fill] if you want the circle to be filled.
    ..style = PaintingStyle.stroke;

  @override
  void paint(Canvas canvas, Size size) {
    canvas.drawOval(
      Rect.fromLTWH(0, 0, size.width, size.height),
      _paint,
    );
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) => false;
}

Usage:

  Widget _buildCircle(BuildContext context) {
    return SizedBox(
      width: 20,
      height: 20,
      child: CustomPaint(
        painter: CirclePainter(),
      ),
    );
  }

AssertNull should be used or AssertNotNull

Use assertNotNull(obj). assert means must be.

What is the difference between a cer, pvk, and pfx file?

In Windows platform, these file types are used for certificate information. Normally used for SSL certificate and Public Key Infrastructure (X.509).

  • CER files: CER file is used to store X.509 certificate. Normally used for SSL certification to verify and identify web servers security. The file contains information about certificate owner and public key. A CER file can be in binary (ASN.1 DER) or encoded with Base-64 with header and footer included (PEM), Windows will recognize either of these layout.
  • PVK files: Stands for Private Key. Windows uses PVK files to store private keys for code signing in various Microsoft products. PVK is proprietary format.
  • PFX files Personal Exchange Format, is a PKCS12 file. This contains a variety of cryptographic information, such as certificates, root authority certificates, certificate chains and private keys. It’s cryptographically protected with passwords to keep private keys private and preserve the integrity of the root certificates. The PFX file is also used in various Microsoft products, such as IIS.

for more information visit:Certificate Files: .Cer x .Pvk x .Pfx

Java logical operator short-circuiting

Logical OR :- returns true if at least one of the operands evaluate to true. Both operands are evaluated before apply the OR operator.

Short Circuit OR :- if left hand side operand returns true, it returns true without evaluating the right hand side operand.

How to run crontab job every week on Sunday

Cron job expression in a human-readable way crontab builder

Best Way to read rss feed in .net Using C#

You're looking for the SyndicationFeed class, which does exactly that.

How to quickly form groups (quartiles, deciles, etc) by ordering column(s) in a data frame

Adapting dplyr::ntile to take advantage of data.table optimizations provides a faster solution.

library(data.table)
setDT(temp)
temp[order(value) , quartile := floor( 1 + 4 * (.I-1) / .N)]

Probably doesn't qualify as cleaner, but it's faster and one-line.

Timing on bigger data set

Comparing this solution to ntile and cut for data.table as proposed by @docendo_discimus and @MichaelChirico.

library(microbenchmark)
library(dplyr)

set.seed(123)

n <- 1e6
temp <- data.frame(name=sample(letters, size=n, replace=TRUE), value=rnorm(n))
setDT(temp)

microbenchmark(
    "ntile" = temp[, quartile_ntile := ntile(value, 4)],
    "cut" = temp[, quartile_cut := cut(value,
                                       breaks = quantile(value, probs = seq(0, 1, by=1/4)),
                                       labels = 1:4, right=FALSE)],
    "dt_ntile" = temp[order(value), quartile_ntile_dt := floor( 1 + 4 * (.I-1)/.N)]
)

Gives:

Unit: milliseconds
     expr      min       lq     mean   median       uq      max neval
    ntile 608.1126 647.4994 670.3160 686.5103 691.4846 712.4267   100
      cut 369.5391 373.3457 375.0913 374.3107 376.5512 385.8142   100
 dt_ntile 117.5736 119.5802 124.5397 120.5043 124.5902 145.7894   100

Dynamically allocating an array of objects

For building containers you obviously want to use one of the standard containers (such as a std::vector). But this is a perfect example of the things you need to consider when your object contains RAW pointers.

If your object has a RAW pointer then you need to remember the rule of 3 (now the rule of 5 in C++11).

  • Constructor
  • Destructor
  • Copy Constructor
  • Assignment Operator
  • Move Constructor (C++11)
  • Move Assignment (C++11)

This is because if not defined the compiler will generate its own version of these methods (see below). The compiler generated versions are not always useful when dealing with RAW pointers.

The copy constructor is the hard one to get correct (it's non trivial if you want to provide the strong exception guarantee). The Assignment operator can be defined in terms of the Copy Constructor as you can use the copy and swap idiom internally.

See below for full details on the absolute minimum for a class containing a pointer to an array of integers.

Knowing that it is non trivial to get it correct you should consider using std::vector rather than a pointer to an array of integers. The vector is easy to use (and expand) and covers all the problems associated with exceptions. Compare the following class with the definition of A below.

class A
{ 
    std::vector<int>   mArray;
    public:
        A(){}
        A(size_t s) :mArray(s)  {}
};

Looking at your problem:

A* arrayOfAs = new A[5];
for (int i = 0; i < 5; ++i)
{
    // As you surmised the problem is on this line.
    arrayOfAs[i] = A(3);

    // What is happening:
    // 1) A(3) Build your A object (fine)
    // 2) A::operator=(A const&) is called to assign the value
    //    onto the result of the array access. Because you did
    //    not define this operator the compiler generated one is
    //    used.
}

The compiler generated assignment operator is fine for nearly all situations, but when RAW pointers are in play you need to pay attention. In your case it is causing a problem because of the shallow copy problem. You have ended up with two objects that contain pointers to the same piece of memory. When the A(3) goes out of scope at the end of the loop it calls delete [] on its pointer. Thus the other object (in the array) now contains a pointer to memory that has been returned to the system.

The compiler generated copy constructor; copies each member variable by using that members copy constructor. For pointers this just means the pointer value is copied from the source object to the destination object (hence shallow copy).

The compiler generated assignment operator; copies each member variable by using that members assignment operator. For pointers this just means the pointer value is copied from the source object to the destination object (hence shallow copy).

So the minimum for a class that contains a pointer:

class A
{
    size_t     mSize;
    int*       mArray;
    public:
         // Simple constructor/destructor are obvious.
         A(size_t s = 0) {mSize=s;mArray = new int[mSize];}
        ~A()             {delete [] mArray;}

         // Copy constructor needs more work
         A(A const& copy)
         {
             mSize  = copy.mSize;
             mArray = new int[copy.mSize];

             // Don't need to worry about copying integers.
             // But if the object has a copy constructor then
             // it would also need to worry about throws from the copy constructor.
             std::copy(&copy.mArray[0],&copy.mArray[c.mSize],mArray);

         }

         // Define assignment operator in terms of the copy constructor
         // Modified: There is a slight twist to the copy swap idiom, that you can
         //           Remove the manual copy made by passing the rhs by value thus
         //           providing an implicit copy generated by the compiler.
         A& operator=(A rhs) // Pass by value (thus generating a copy)
         {
             rhs.swap(*this); // Now swap data with the copy.
                              // The rhs parameter will delete the array when it
                              // goes out of scope at the end of the function
             return *this;
         }
         void swap(A& s) noexcept
         {
             using std::swap;
             swap(this.mArray,s.mArray);
             swap(this.mSize ,s.mSize);
         }

         // C++11
         A(A&& src) noexcept
             : mSize(0)
             , mArray(NULL)
         {
             src.swap(*this);
         }
         A& operator=(A&& src) noexcept
         {
             src.swap(*this);     // You are moving the state of the src object
                                  // into this one. The state of the src object
                                  // after the move must be valid but indeterminate.
                                  //
                                  // The easiest way to do this is to swap the states
                                  // of the two objects.
                                  //
                                  // Note: Doing any operation on src after a move 
                                  // is risky (apart from destroy) until you put it 
                                  // into a specific state. Your object should have
                                  // appropriate methods for this.
                                  // 
                                  // Example: Assignment (operator = should work).
                                  //          std::vector() has clear() which sets
                                  //          a specific state without needing to
                                  //          know the current state.
             return *this;
         }   
 }

What is Java EE?

It's meaning changes all the time. It used to mean Servlets and JSP and EJBs. Now-a-days it probably means Spring and Hibernate etc.

Really what they are looking for is experience and understanding of the Java ecosystem, Servlet containers, JMS, JMX, Hibernate etc. and how they all fit together.

Testing and source control would be an important skills too.

How to filter (key, value) with ng-repeat in AngularJs?

Also you can use ng-repeat with ng-if:

<div ng-repeat="(key, value) in order" ng-if="value > 0">

JSF rendered multiple combined conditions

Assuming that "a" and "b" are bean properties

rendered="#{bean.a==12 and (bean.b==13 or bean.b==15)}"

You may look at JSF EL operators

Two arrays in foreach loop

<?php

$codes = array ('tn','us','fr');
$names = array ('Tunisia','United States','France');

echo '<table>';

foreach(array_keys($codes) as $i) {

     echo '<tr><td>';
     echo ($i + 1);
     echo '</td><td>';
     echo $codes[$i];
     echo '</td><td>';
     echo $names[$i];
     echo '</td></tr>';
}

echo '</table>';

?>

How do I remove the non-numeric character from a string in java?

This works in Flex SDK 4.14.0

myString.replace(/[^0-9&&^.]/g, "");

Specify sudo password for Ansible

You can use ansible vault which will code your password into encrypted vault. After that you can use variable from vault in playbooks.

Some documentation on ansible vault:
http://docs.ansible.com/playbooks_vault.html

We are using it as vault per environment. To edit vault we have command as:
ansible-vault edit inventories/production/group_vars/all/vault

If you want to call vault variable you have to use ansible-playbook with parameters like:
ansible-playbook -s --vault-password-file=~/.ansible_vault.password

Yes we are storing vault password in local directory in plain text but it's not more dangerous like store root password for every system. Root password is inside vault file or you can have it like sudoers file for your user/group.

I'm recommending to use sudoers file on the server. Here is example for group admin:
%admin ALL=(ALL) NOPASSWD:ALL

Bootstrap carousel multiple frames at once

Can this be done with bootstrap 3's carousel? I'm hoping I won't have to go hunting for yet another jQuery plugin

As of 2013-12-08 the answer is no. The effect you are looking for is not possible using Bootstrap 3's generic carousel plugin. However, here's a simple jQuery plugin that seems to do exactly what you want http://sorgalla.com/jcarousel/

Reading e-mails from Outlook with Python through MAPI

Sorry for my bad English. Checking Mails using Python with MAPI is easier,

outlook =win32com.client.Dispatch("Outlook.Application").GetNamespace("MAPI")
folder = outlook.Folders[5]
Subfldr = folder.Folders[5]
messages_REACH = Subfldr.Items
message = messages_REACH.GetFirst()

Here we can get the most first mail into the Mail box, or into any sub folder. Actually, we need to check the Mailbox number & orientation. With the help of this analysis we can check each mailbox & its sub mailbox folders.

Similarly please find the below code, where we can see, the last/ earlier mails. How we need to check.

`outlook =win32com.client.Dispatch("Outlook.Application").GetNamespace("MAPI")
folder = outlook.Folders[5]
Subfldr = folder.Folders[5]
messages_REACH = Subfldr.Items
message = messages_REACH.GetLast()`

With this we can get most recent email into the mailbox. According to the above mentioned code, we can check our all mail boxes, & its sub folders.

Get CPU Usage from Windows Command Prompt

C:\> wmic cpu get loadpercentage
LoadPercentage
0

Or

C:\> @for /f "skip=1" %p in ('wmic cpu get loadpercentage') do @echo %p%
4%

react-native :app:installDebug FAILED

Previously, I had installed npm and then installed yarn, and that is when I started to have problems compiling, even when creating new projects with react-native init . Uninstalling yarn, I was able to create and compile.

How do I install a custom font on an HTML site

You can use @font-face in most modern browsers.

Here's some articles on how it works:

Here is a good syntax for adding the font to your app:

Here are a couple of places to convert fonts for use with @font-face:

Also cufon will work if you don't want to use font-face, and it has good documentation on the web site:

How do I clear this setInterval inside a function?

Simplest way I could think of: add a class.

Simply add a class (on any element) and check inside the interval if it's there. This is more reliable, customisable and cross-language than any other way, I believe.

_x000D_
_x000D_
var i = 0;_x000D_
this.setInterval(function() {_x000D_
  if(!$('#counter').hasClass('pauseInterval')) { //only run if it hasn't got this class 'pauseInterval'_x000D_
    console.log('Counting...');_x000D_
    $('#counter').html(i++); //just for explaining and showing_x000D_
  } else {_x000D_
    console.log('Stopped counting');_x000D_
  }_x000D_
}, 500);_x000D_
_x000D_
/* In this example, I'm adding a class on mouseover and remove it again on mouseleave. You can of course do pretty much whatever you like */_x000D_
$('#counter').hover(function() { //mouse enter_x000D_
    $(this).addClass('pauseInterval');_x000D_
  },function() { //mouse leave_x000D_
    $(this).removeClass('pauseInterval');_x000D_
  }_x000D_
);_x000D_
_x000D_
/* Other example */_x000D_
$('#pauseInterval').click(function() {_x000D_
  $('#counter').toggleClass('pauseInterval');_x000D_
});
_x000D_
body {_x000D_
  background-color: #eee;_x000D_
  font-family: Calibri, Arial, sans-serif;_x000D_
}_x000D_
#counter {_x000D_
  width: 50%;_x000D_
  background: #ddd;_x000D_
  border: 2px solid #009afd;_x000D_
  border-radius: 5px;_x000D_
  padding: 5px;_x000D_
  text-align: center;_x000D_
  transition: .3s;_x000D_
  margin: 0 auto;_x000D_
}_x000D_
#counter.pauseInterval {_x000D_
  border-color: red;  _x000D_
}
_x000D_
<!-- you'll need jQuery for this. If you really want a vanilla version, ask -->_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
_x000D_
<p id="counter">&nbsp;</p>_x000D_
<button id="pauseInterval">Pause/unpause</button></p>
_x000D_
_x000D_
_x000D_

Java default constructor

If a class doesn't have any constructor provided by programmer, then java compiler will add a default constructor with out parameters which will call super class constructor internally with super() call. This is called as default constructor.

In your case, there is no default constructor as you are adding them programmatically. If there are no constructors added by you, then compiler generated default constructor will look like this.

public Module()
{
   super();
}

Note: In side default constructor, it will add super() call also, to call super class constructor.

Purpose of adding default constructor:

Constructor's duty is to initialize instance variables, if there are no instance variables you could choose to remove constructor from your class. But when you are inheriting some class it is your class responsibility to call super class constructor to make sure that super class initializes all its instance variables properly.

That's why if there are no constructors, java compiler will add a default constructor and calls super class constructor.

Transaction marked as rollback only: How do I find the cause

To quickly fetch the causing exception without the need to re-code or rebuild, set a breakpoint on

org.hibernate.ejb.TransactionImpl.setRollbackOnly() // Hibernate < 4.3, or
org.hibernate.jpa.internal.TransactionImpl() // as of Hibernate 4.3

and go up in the stack, usually to some Interceptor. There you can read the causing exception from some catch block.

How to retry image pull in a kubernetes Pods?

Most probably the issue of ImagePullBackOff is due to either the image not being present or issue with the pod YAML file.

What I will do is this

kubectl get pod -n $namespace $POD_NAME --export > pod.yaml | kubectl -f apply -

I would also see the pod.yaml to see the why the earlier pod didn't work

How do I remove all non alphanumeric characters from a string except dash?

Here's an extension method using @ata answer as inspiration.

"hello-world123, 456".MakeAlphaNumeric(new char[]{'-'});// yields "hello-world123456"

or if you require additional characters other than hyphen...

"hello-world123, 456!?".MakeAlphaNumeric(new char[]{'-','!'});// yields "hello-world123456!"


public static class StringExtensions
{   
    public static string MakeAlphaNumeric(this string input, params char[] exceptions)
    {
        var charArray = input.ToCharArray();
        var alphaNumeric = Array.FindAll<char>(charArray, (c => char.IsLetterOrDigit(c)|| exceptions?.Contains(c) == true));
        return new string(alphaNumeric);
    }
}

How do you comment an MS-access Query?

In the query design:

  • add a column
  • enter your comment (in quotes) in the field
  • uncheck Show
  • sort in assending.

Note:

If you don't sort, the field will be removed by access. So, make sure you've unchecked show and sorted the column.

Division of integers in Java

Converting the output is too late; the calculation has already taken place in integer arithmetic. You need to convert the inputs to double:

System.out.println((double)completed/(double)total);

Note that you don't actually need to convert both of the inputs. So long as one of them is double, the other will be implicitly converted. But I prefer to do both, for symmetry.

How can I remove jenkins completely from linux

On Centos7, It is important to note that while you remove jenkins using following command: sudo yum remove jenkins

it will not remove your users and other information. For that you will have to do following: sudo rm -r /var/lib/jenkins

How to check if a date is in a given range?

Convert both dates to timestamps then do

pseudocode:

if date_from_user > start_date && date_from_user < end_date
    return true

NullPointerException: Attempt to invoke virtual method 'int java.util.ArrayList.size()' on a null object reference

This issue is due to ArrayList variable not being instantiated. Need to declare "recordings" variable like following, that should solve the issue;

ArrayList<String> recordings = new ArrayList<String>();

this calls default constructor and assigns empty string to the recordings variable so that it is not null anymore.

Easiest way to copy a table from one database to another?

Is this something you need to do regularly, or just a one off?

You can do an export (eg using phpMyAdmin or similar) that will script out your table and its contents to a text file, then you could re-import that into the other Database.

Cache an HTTP 'Get' service response in AngularJS?

In Angular 8 we can do like this:

import { Injectable } from '@angular/core';
import { YourModel} from '../models/<yourModel>.model';
import { UserService } from './user.service';
import { Observable, of } from 'rxjs';
import { map, catchError } from 'rxjs/operators';
import { HttpClient } from '@angular/common/http';

@Injectable({
  providedIn: 'root'
})

export class GlobalDataService {

  private me: <YourModel>;

  private meObservable: Observable<User>;

  constructor(private yourModalService: <yourModalService>, private http: HttpClient) {

  }

  ngOnInit() {

  }


  getYourModel(): Observable<YourModel> {

    if (this.me) {
      return of(this.me);
    } else if (this.meObservable) {
      return this.meObservable;
    }
    else {
      this.meObservable = this.yourModalService.getCall<yourModel>() // Your http call
      .pipe(
        map(data => {
          this.me = data;
          return data;
        })
      );
      return this.meObservable;
    }
  }
}

You can call it like this:

this.globalDataService.getYourModel().subscribe(yourModel => {


});

The above code will cache the result of remote API at first call so that it can be used on further requests to that method.

configure: error: C compiler cannot create executables

Check where your clang is located:

which clang

It should be somewhere under /usr/bin/clang. In my case from old times it was coming from Miniconda that was put artificially on the command line PATH. Fix that so that clang comes from Xcode and that should bring you forward.

Android - how to make a scrollable constraintlayout?

Constraintlayout is the Default for a new app. I am "learning to Android" now and had a very hard time figuring out how to handle the default "sample" code to scroll when a keyboard is up. I have seen many apps where I have to close the keyboard to click "submit" button and sometimes it does not goes away. Using this [ScrollView / ContraintLayout / Fields] hierarchy it is working just fine now. This way we can have the benefits and ease of use from ConstraintLayout in a scrollable view.

What does cmd /C mean?

The part you should be interested in is the /? part, which should solve most other questions you have with the tool.

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\>cmd /?
Starts a new instance of the Windows XP command interpreter

CMD [/A | /U] [/Q] [/D] [/E:ON | /E:OFF] [/F:ON | /F:OFF] [/V:ON | /V:OFF]
    [[/S] [/C | /K] string]

/C      Carries out the command specified by string and then terminates
/K      Carries out the command specified by string but remains
/S      Modifies the treatment of string after /C or /K (see below)
/Q      Turns echo off
/D      Disable execution of AutoRun commands from registry (see below)
/A      Causes the output of internal commands to a pipe or file to be ANSI
/U      Causes the output of internal commands to a pipe or file to be
        Unicode
/T:fg   Sets the foreground/background colors (see COLOR /? for more info)
/E:ON   Enable command extensions (see below)
/E:OFF  Disable command extensions (see below)
/F:ON   Enable file and directory name completion characters (see below)
/F:OFF  Disable file and directory name completion characters (see below)
/V:ON   Enable delayed environment variable expansion using ! as the
        delimiter. For example, /V:ON would allow !var! to expand the
        variable var at execution time.  The var syntax expands variables
        at input time, which is quite a different thing when inside of a FOR
        loop.
/V:OFF  Disable delayed environment expansion.

Apache is downloading php files instead of displaying them

I got this kind of problem. This is how I solve it. After installed Apache then I installed PHP using this command.

sudo apt-get install php libapache2-mod-php

it executes correctly but I request .php file from Apache, it gives without executing the PHP script.

Then I check PHP is enabled.

$ cd /etc/apache2
$ ls -l mods-*/*php*

but it didn't show any results. I check installed PHP packages.

$ dpkg -l | grep php| awk '{print $2}' |tr "\n" " "

Different type of PHP versions installed to my computer. Then I remove some PHP packages from my previous list, using apt-get purge.

sudo apt-get purge libapache2-mod-php7.0 php7.0 php7.0-cli php7.0-common php7.0-json

I reinstall PHP

sudo apt-get install php libapache2-mod-php php-mcrypt php-mysql

Verify that the PHP module is loaded

$ a2query -m php7.0

if not enabled with:

$ sudo a2enmod php7.0

Restart Apache server

$ sudo systemctl restart apache2

Finally, I check PHP process on Apache

create an empty file

sudo vim /var/www/html/info.php

Add this content to info.php & save.

<?php
  phpinfo();
?>

Check on browser:

http://localhost/info.php

it shows correctly.I think this will help anyone.

With ' N ' no of nodes, how many different Binary and Binary Search Trees possible?

  1. Total no of Binary Trees are = enter image description![enter image description here

  2. Summing over i gives the total number of binary search trees with n nodes. enter image description here

The base case is t(0) = 1 and t(1) = 1, i.e. there is one empty BST and there is one BST with one node. enter image description here

So, In general you can compute total no of Binary Search Trees using above formula. I was asked a question in Google interview related on this formula. Question was how many total no of Binary Search Trees are possible with 6 vertices. So Answer is t(6) = 132

I think that I gave you some idea...

How to call window.alert("message"); from C#?

if you are using ajax in your page that require script manager Page.ClientScript
will not work, Try this and it would do the work:

ScriptManager.RegisterClientScriptBlock(this, GetType(),
            "alertMessage", @"alert('your Message ')", true);

Getting command-line password input in Python

This code will print an asterisk instead of every letter.

import sys
import msvcrt

passwor = ''
while True:
    x = msvcrt.getch()
    if x == '\r':
        break
    sys.stdout.write('*')
    passwor +=x

print '\n'+passwor

Replace text inside td using jQuery having td containing other elements

$('#demoTable td').contents().each(function() {
    if (this.nodeType === 3) {
        this.textContent
        ? this.textContent = 'The text has been '
        : this.innerText  = 'The text has been '
    } else {
        this.innerHTML = 'changed';
        return false;
    }
})

http://jsfiddle.net/YSAjU/

Command for restarting all running docker containers?

For me its now :

docker restart $(docker ps -a -q)

What is the syntax of the enhanced for loop in Java?

Enhanced for loop:

for (String element : array) {

    // rest of code handling current element
}

Traditional for loop equivalent:

for (int i=0; i < array.length; i++) {
    String element = array[i]; 

    // rest of code handling current element
}

Take a look at these forums: https://blogs.oracle.com/CoreJavaTechTips/entry/using_enhanced_for_loops_with

http://www.java-tips.org/java-se-tips/java.lang/the-enhanced-for-loop.html