Programs & Examples On #Brownfield

Brownfield development is a term commonly used in the IT industry to describe problem spaces needing the development and deployment of new software systems in the immediate presence of existing (legacy) software applications/systems. This implies that any new software architecture must take into account and coexist with live software already in situ.

flutter run: No connected devices

If the emulator is running and is not being detected by the flutter and adb devices then try connecting it manually by using the following command

abd connect 127.0.0.1:62001

If it fails to connect, try again. The following message should appear

connected to 127.0.0.1:62001

Then try flutter doctor or adb devices to make sure it has been connected successfully.

Finding all possible combinations of numbers to reach a given sum

I ported the C# sample to Objective-c and didn't see it in the responses:

//Usage
NSMutableArray* numberList = [[NSMutableArray alloc] init];
NSMutableArray* partial = [[NSMutableArray alloc] init];
int target = 16;
for( int i = 1; i<target; i++ )
{ [numberList addObject:@(i)]; }
[self findSums:numberList target:target part:partial];


//*******************************************************************
// Finds combinations of numbers that add up to target recursively
//*******************************************************************
-(void)findSums:(NSMutableArray*)numbers target:(int)target part:(NSMutableArray*)partial
{
    int s = 0;
    for (NSNumber* x in partial)
    { s += [x intValue]; }

    if (s == target)
    { NSLog(@"Sum[%@]", partial); }

    if (s >= target)
    { return; }

    for (int i = 0;i < [numbers count];i++ )
    {
        int n = [numbers[i] intValue];
        NSMutableArray* remaining = [[NSMutableArray alloc] init];
        for (int j = i + 1; j < [numbers count];j++)
        { [remaining addObject:@([numbers[j] intValue])]; }

        NSMutableArray* partRec = [[NSMutableArray alloc] initWithArray:partial];
        [partRec addObject:@(n)];
        [self findSums:remaining target:target part:partRec];
    }
}

How to use a SQL SELECT statement with Access VBA

Here is another way to use SQL SELECT statement in VBA:

 sSQL = "SELECT Variable FROM GroupTable WHERE VariableCode = '" & Me.comboBox & "'" 
 Set rs = CurrentDb.OpenRecordset(sSQL)
 On Error GoTo resultsetError 
 dbValue = rs!Variable
 MsgBox dbValue, vbOKOnly, "RS VALUE"
resultsetError:
 MsgBox "Error Retrieving value from database",VbOkOnly,"Database Error"

How to correctly iterate through getElementsByClassName

 <!--something like this--> 
<html>
<body>



<!-- i've used for loop...this pointer takes current element to apply a 
 particular change on it ...other elements take change by else condition 
-->  


<div class="classname" onclick="myFunction(this);">first</div>  
<div class="classname" onclick="myFunction(this);">second</div>


<script>
function myFunction(p) {
 var x = document.getElementsByClassName("classname");
 var i;
 for (i = 0; i < x.length; i++) {
    if(x[i] == p)
    {
x[i].style.background="blue";
    }
    else{
x[i].style.background="red";
    }
}
}


</script>
<!--this script will only work for a class with onclick event but if u want 
to use all class of same name then u can use querySelectorAll() ...-->




var variable_name=document.querySelectorAll('.classname');
for(var i=0;i<variable_name.length;i++){
variable_name[i].(--your option--);
}



 <!--if u like to divide it on some logic apply it inside this for loop 
 using your nodelist-->

</body>
</html>

SQL select everything in an array

$SQL_Part="("
$i=0;
while ($i<length($cat)-1)
{
   $SQL_Part+=$cat[i]+",";
}
$SQL_Part=$SQL_Part+$cat[$i+1]+")"

$SQL="SELECT * FROM products WHERE catid IN "+$SQL_Part;

It's more generic and will fit for any array!!

The type is defined in an assembly that is not referenced, how to find the cause?

In my case the version of the dll referenced was actually newer than the one that I had before.

I just needed to roll back to the previous release and that fixed it.

Is there a way to get the XPath in Google Chrome?

For Chrome, for instance:

  1. Right-click "inspect" on the item you are trying to find the XPath.
  2. Right-click on the highlighted area on the HTML DOM.
  3. Go to Copy > select 'Copy XPath'.
  4. After the above step, you will get the absolute XPath of the element from DOM.
  5. You can make changes to make it relative XPath (because if the DOM changes, still your XPath would be able to find the element).

a. To do so, by opening the 'Elements' panel of the browser, press CTRL+F, paste the XPath.

b. Make changes as describes in the following example.

Absolute xpath = //*[@id="app"]/div[1]/header/nav/div[2]/ul/li[2]/div/button

Related xpath = //div//nav/div[2]/ul/li[2]/div/button

When you make changes:

  1. make sure the XPath is unique within the DOM.
  2. still the web element is selected on the DOM and on the webpage.

Convert date formats in bash

Maybe something changed since 2011 but this worked for me:

$ date +"%Y%m%d"
20150330

No need for the -d to get the same appearing result.

How to set JAVA_HOME for multiple Tomcat instances?

Linux based Tomcat6 should have /etc/tomcat6/tomcat6.conf

# System-wide configuration file for tomcat6 services
# This will be sourced by tomcat6 and any secondary service
# Values will be overridden by service-specific configuration
# files in /etc/sysconfig
#
# Use this one to change default values for all services
# Change the service specific ones to affect only one service
# (see, for instance, /etc/sysconfig/tomcat6)
#

# Where your java installation lives
#JAVA_HOME="/usr/lib/jvm/java-1.5.0"

# Where your tomcat installation lives
CATALINA_BASE="/usr/share/tomcat6"
...

JSON Parse File Path

My case of working code is:

var request = new XMLHttpRequest();
request.open("GET", "<path_to_file>", false);
request.overrideMimeType("application/json");
request.send(null);
var jsonData = JSON.parse(request.responseText);
console.log(jsonData);

Jenkins not executing jobs (pending - waiting for next executor)

For me below solution worked.

Jenkins --> Manage Jenkins --> Manage Nodes --> master -> configure --> Node properties --> Restrict Jobs execution at node - is enabled and given access to specific users. I have given access myself and then job started to run.

If Restrict Jobs execution at node is enabled scheduled tasks cannot run.

How to convert a factor to integer\numeric without loss of information?

Looks like the solution as.numeric(levels(f))[f] no longer work with R 4.0.

Alternative solution:

factor2number <- function(x){
    data.frame(levels(x), 1:length(levels(x)), row.names = 1)[x, 1]
}

factor2number(yourFactor)

Drop rows with all zeros in pandas data frame

I think this solution is the shortest :

df= df[df['ColName'] != 0]

Is it possible to 'prefill' a google form using data from a google spreadsheet?

You can create a pre-filled form URL from within the Form Editor, as described in the documentation for Drive Forms. You'll end up with a URL like this, for example:

https://docs.google.com/forms/d/--form-id--/viewform?entry.726721210=Mike+Jones&entry.787184751=1975-05-09&entry.1381372492&entry.960923899

buildUrls()

In this example, question 1, "Name", has an ID of 726721210, while question 2, "Birthday" is 787184751. Questions 3 and 4 are blank.

You could generate the pre-filled URL by adapting the one provided through the UI to be a template, like this:

function buildUrls() {
  var template = "https://docs.google.com/forms/d/--form-id--/viewform?entry.726721210=##Name##&entry.787184751=##Birthday##&entry.1381372492&entry.960923899";
  var ss = SpreadsheetApp.getActive().getSheetByName("Sheet1");  // Email, Name, Birthday
  var data = ss.getDataRange().getValues();

  // Skip headers, then build URLs for each row in Sheet1.
  for (var i = 1; i < data.length; i++ ) {
    var url = template.replace('##Name##',escape(data[i][1]))
                      .replace('##Birthday##',data[i][2].yyyymmdd());  // see yyyymmdd below
    Logger.log(url);  // You could do something more useful here.
  }
};

This is effective enough - you could email the pre-filled URL to each person, and they'd have some questions already filled in.

betterBuildUrls()

Instead of creating our template using brute force, we can piece it together programmatically. This will have the advantage that we can re-use the code without needing to remember to change the template.

Each question in a form is an item. For this example, let's assume the form has only 4 questions, as you've described them. Item [0] is "Name", [1] is "Birthday", and so on.

We can create a form response, which we won't submit - instead, we'll partially complete the form, only to get the pre-filled form URL. Since the Forms API understands the data types of each item, we can avoid manipulating the string format of dates and other types, which simplifies our code somewhat.

(EDIT: There's a more general version of this in How to prefill Google form checkboxes?)

/**
 * Use Form API to generate pre-filled form URLs
 */
function betterBuildUrls() {
  var ss = SpreadsheetApp.getActive();
  var sheet = ss.getSheetByName("Sheet1");
  var data = ss.getDataRange().getValues();  // Data for pre-fill

  var formUrl = ss.getFormUrl();             // Use form attached to sheet
  var form = FormApp.openByUrl(formUrl);
  var items = form.getItems();

  // Skip headers, then build URLs for each row in Sheet1.
  for (var i = 1; i < data.length; i++ ) {
    // Create a form response object, and prefill it
    var formResponse = form.createResponse();

    // Prefill Name
    var formItem = items[0].asTextItem();
    var response = formItem.createResponse(data[i][1]);
    formResponse.withItemResponse(response);

    // Prefill Birthday
    formItem = items[1].asDateItem();
    response = formItem.createResponse(data[i][2]);
    formResponse.withItemResponse(response);

    // Get prefilled form URL
    var url = formResponse.toPrefilledUrl();
    Logger.log(url);  // You could do something more useful here.
  }
};

yymmdd Function

Any date item in the pre-filled form URL is expected to be in this format: yyyy-mm-dd. This helper function extends the Date object with a new method to handle the conversion.

When reading dates from a spreadsheet, you'll end up with a javascript Date object, as long as the format of the data is recognizable as a date. (Your example is not recognizable, so instead of May 9th 1975 you could use 5/9/1975.)

// From http://blog.justin.kelly.org.au/simple-javascript-function-to-format-the-date-as-yyyy-mm-dd/
Date.prototype.yyyymmdd = function() {
  var yyyy = this.getFullYear().toString();                                    
  var mm = (this.getMonth()+1).toString(); // getMonth() is zero-based         
  var dd  = this.getDate().toString();             

  return yyyy + '-' + (mm[1]?mm:"0"+mm[0]) + '-' + (dd[1]?dd:"0"+dd[0]);
};

Running Python in PowerShell?

Go to Control Panel ? System and Security ? System, and then click Advanced system settings on the left hand side menu.

On the Advanced tab, click Environment Variables.

Under 'User variables' append the PATH variable with path to your Python install directory:

C:\Python27;

C# switch on type

I did it one time with a workaround, hope it helps.

string fullName = typeof(MyObj).FullName;

switch (fullName)
{
    case "fullName1":
    case "fullName2":
    case "fullName3":
}

How to parse a JSON string into JsonNode in Jackson?

New approach to old question. A solution that works from java 9+

ObjectNode agencyNode = new ObjectMapper().valueToTree(Map.of("key", "value"));

is more readable and maintainable for complex objects. Ej

Map<String, Object> agencyMap = Map.of(
        "name", "Agencia Prueba",
        "phone1", "1198788373",
        "address", "Larrea 45 e/ calligaris y paris",
        "number", 267,
        "enable", true,
        "location", Map.of("id", 54),
        "responsible", Set.of(Map.of("id", 405)),
        "sellers", List.of(Map.of("id", 605))
);
ObjectNode agencyNode = new ObjectMapper().valueToTree(agencyMap);

How to perform a LEFT JOIN in SQL Server between two SELECT statements?

Try this:

SELECT user.userID, edge.TailUser, edge.Weight 
FROM user
LEFT JOIN edge ON edge.HeadUser = User.UserID
WHERE edge.HeadUser=5043

OR

AND edge.HeadUser=5043

instead of WHERE clausule.

Real time face detection OpenCV, Python

Your line:

img = cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2) 

will draw a rectangle in the image, but the return value will be None, so img changes to None and cannot be drawn.

Try

cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2) 

How do I determine the size of an object in Python?

You can serialize the object to derive a measure that is closely related to the size of the object:

import pickle

## let o be the object whose size you want to measure
size_estimate = len(pickle.dumps(o))

If you want to measure objects that cannot be pickled (e.g. because of lambda expressions) dill or cloudpickle can be a solution.

Python: Get the first character of the first string in a list?

Indexing in python starting from 0. You wrote [1:] this would not return you a first char in any case - this will return you a rest(except first char) of string.

If you have the following structure:

mylist = ['base', 'sample', 'test']

And want to get fist char for the first one string(item):

myList[0][0]
>>> b

If all first chars:

[x[0] for x in myList]
>>> ['b', 's', 't']    

If you have a text:

text = 'base sample test'
text.split()[0][0]
>>> b

Error converting data types when importing from Excel to SQL Server 2008

Going off of what Derloopkat said, which still can fail on conversion (no offense Derloopkat) because Excel is terrible at this:

  1. Paste from excel into Notepad and save as normal (.txt file).
  2. From within excel, open said .txt file.
  3. Select next as it is obviously tab delimited.
  4. Select "none" for text qualifier, then next again.
  5. Select the first row, hold shift, select the last row, and select the text radial button. Click Finish

It will open, check it to make sure it's accurate and then save as an excel file.

Remove Datepicker Function dynamically

Destroy the datepicker's instance when you don't want it and create new instance whenever necessary.

I know this is ugly but only this seems to be working...

Check this out

 $("#ddlSearchType").change(function () {
        if ($(this).val() == "Required Date" || $(this).val() == "Submitted Date") {
                $("#txtSearch").datepicker();

         }
          else {
                $("#txtSearch").datepicker("destroy");                    
         }
 });

How to have Java method return generic list of any type?

I'm pretty sure you can completely delete the <stuff> , which will generate a warning and you can use an, @ suppress warnings. If you really want it to be generic, but to use any of its elements you will have to do type casting. For instance, I made a simple bubble sort function and it uses a generic type when sorting the list, which is actually an array of Comparable in this case. If you wish to use an item, do something like: System.out.println((Double)arrayOfDoubles[0] + (Double)arrayOfDoubles[1]); because I stuffed Double(s) into Comparable(s) which is polymorphism since all Double(s) inherit from Comparable to allow easy sorting through Collections.sort()

        //INDENT TO DISPLAY CODE ON STACK-OVERFLOW
@SuppressWarnings("unchecked")
public static void simpleBubbleSort_ascending(@SuppressWarnings("rawtypes") Comparable[] arrayOfDoubles)
{
//VARS
    //looping
    int end      =      arrayOfDoubles.length - 1;//the last index in our loops
    int iterationsMax = arrayOfDoubles.length - 1;

    //swapping
    @SuppressWarnings("rawtypes")
    Comparable tempSwap = 0.0;//a temporary double used in the swap process
    int elementP1 = 1;//element + 1,   an index for comparing and swapping


//CODE
    //do up to 'iterationsMax' many iterations
    for (int iteration = 0; iteration < iterationsMax; iteration++)
    {
        //go through each element and compare it to the next element
        for (int element = 0; element < end; element++)
        {
            elementP1 = element + 1;

            //if the elements need to be swapped, swap them
            if (arrayOfDoubles[element].compareTo(arrayOfDoubles[elementP1])==1)
            {
                //swap
                tempSwap = arrayOfDoubles[element];
                arrayOfDoubles[element] = arrayOfDoubles[elementP1];
                arrayOfDoubles[elementP1] = tempSwap;
            }
        }
    }
}//END public static void simpleBubbleSort_ascending(double[] arrayOfDoubles)

How to close activity and go back to previous activity in android

if you use fragment u should use

getActivity().onBackPressed();

if you use single activity u can use

finish();

python: how to get information about a function?

Or

help(list.append)

if you're generally poking around.

R Error in x$ed : $ operator is invalid for atomic vectors

From the help file about $ (See ?"$") you can read:

$ is only valid for recursive objects, and is only discussed in the section below on recursive objects.

Now, let's check whether x is recursive

> is.recursive(x)
[1] FALSE

A recursive object has a list-like structure. A vector is not recursive, it is an atomic object instead, let's check

> is.atomic(x)
[1] TRUE

Therefore you get an error when applying $ to a vector (non-recursive object), use [ instead:

> x["ed"]
ed 
 2 

You can also use getElement

> getElement(x, "ed")
[1] 2

How to extract the file name from URI returned from Intent.ACTION_GET_CONTENT?

developer.android.com has nice example code for this: https://developer.android.com/guide/topics/providers/document-provider.html

A condensed version to just extract the file name (assuming "this" is an Activity):

public String getFileName(Uri uri) {
  String result = null;
  if (uri.getScheme().equals("content")) {
    Cursor cursor = getContentResolver().query(uri, null, null, null, null);
    try {
      if (cursor != null && cursor.moveToFirst()) {
        result = cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME));
      }
    } finally {
      cursor.close();
    }
  }
  if (result == null) {
    result = uri.getPath();
    int cut = result.lastIndexOf('/');
    if (cut != -1) {
      result = result.substring(cut + 1);
    }
  }
  return result;
}

Matplotlib (pyplot) savefig outputs blank image

let's me give a more detail example:

import numpy as np
import matplotlib.pyplot as plt


def draw_result(lst_iter, lst_loss, lst_acc, title):
    plt.plot(lst_iter, lst_loss, '-b', label='loss')
    plt.plot(lst_iter, lst_acc, '-r', label='accuracy')

    plt.xlabel("n iteration")
    plt.legend(loc='upper left')
    plt.title(title)
    plt.savefig(title+".png")  # should before plt.show method

    plt.show()


def test_draw():
    lst_iter = range(100)
    lst_loss = [0.01 * i + 0.01 * i ** 2 for i in xrange(100)]
    # lst_loss = np.random.randn(1, 100).reshape((100, ))
    lst_acc = [0.01 * i - 0.01 * i ** 2 for i in xrange(100)]
    # lst_acc = np.random.randn(1, 100).reshape((100, ))
    draw_result(lst_iter, lst_loss, lst_acc, "sgd_method")


if __name__ == '__main__':
    test_draw()

enter image description here

Deleting Elements in an Array if Element is a Certain value VBA

here is a sample of code using the CopyMemory function to do the job.

It is supposedly "much faster" (depending of the size and type of the array...).

i am not the author, but i tested it :

Sub RemoveArrayElement_Str(ByRef AryVar() As String, ByVal RemoveWhich As Long) 

'// The size of the array elements
'// In the case of string arrays, they are
'// simply 32 bit pointers to BSTR's.
Dim byteLen As Byte

'// String pointers are 4 bytes
byteLen = 4

'// The copymemory operation is not necessary unless
'// we are working with an array element that is not
'// at the end of the array
If RemoveWhich < UBound(AryVar) Then
    '// Copy the block of string pointers starting at
    ' the position after the
    '// removed item back one spot.
    CopyMemory ByVal VarPtr(AryVar(RemoveWhich)), ByVal _
        VarPtr(AryVar(RemoveWhich + 1)), (byteLen) * _
        (UBound(AryVar) - RemoveWhich)
End If

'// If we are removing the last array element
'// just deinitialize the array
'// otherwise chop the array down by one.
If UBound(AryVar) = LBound(AryVar) Then
    Erase AryVar
Else
    ReDim Preserve AryVar(LBound(AryVar) To UBound(AryVar) - 1)
End If
End Sub

Split string using a newline delimiter with Python

If you want to split only by newlines, you can use str.splitlines():

Example:

>>> data = """a,b,c
... d,e,f
... g,h,i
... j,k,l"""
>>> data
'a,b,c\nd,e,f\ng,h,i\nj,k,l'
>>> data.splitlines()
['a,b,c', 'd,e,f', 'g,h,i', 'j,k,l']

With str.split() your case also works:

>>> data = """a,b,c
... d,e,f
... g,h,i
... j,k,l"""
>>> data
'a,b,c\nd,e,f\ng,h,i\nj,k,l'
>>> data.split()
['a,b,c', 'd,e,f', 'g,h,i', 'j,k,l']

However if you have spaces (or tabs) it will fail:

>>> data = """
... a, eqw, qwe
... v, ewr, err
... """
>>> data
'\na, eqw, qwe\nv, ewr, err\n'
>>> data.split()
['a,', 'eqw,', 'qwe', 'v,', 'ewr,', 'err']

Setting environment variables in Linux using Bash

VAR=value sets VAR to value.

After that export VAR will give it to child processes too.

export VAR=value is a shorthand doing both.

How to remove "Server name" items from history of SQL Server Management Studio

Over on this duplicate question @arcticdev posted some code that will get rid of individual entries (as opposed to all entries being delete the bin file). I have wrapped it in a very ugly UI and put it here: http://ssmsmru.codeplex.com/

Entity Framework Core add unique constraint code-first

The OP is asking about whether it is possible to add an Attribute to an Entity class for a Unique Key. The short answer is that it IS possible, but not an out-of-the-box feature from the EF Core Team. If you'd like to use an Attribute to add Unique Keys to your Entity Framework Core entity classes, you can do what I've posted here

public class Company
{
    [Required]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public Guid CompanyId { get; set; }

    [Required]
    [UniqueKey(groupId: "1", order: 0)]
    [StringLength(100, MinimumLength = 1)]
    public string CompanyName { get; set; }

    [Required]
    [UniqueKey(groupId: "1", order: 1)]
    [StringLength(100, MinimumLength = 1)]
    public string CompanyLocation { get; set; }
}

How to add favicon.ico in ASP.NET site

_x000D_
_x000D_
    <link rel="shortcut icon" type="image/x-icon" href="~/favicon.ico" />
_x000D_
_x000D_
_x000D_

This worked for me. If anyone is troubleshooting while reading this - I found issues when my favicon.ico was not nested in the root folder. I had mine in the Resources folder and was struggling at that point.

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

We dont need redux-persist we can simply use redux for persistance.

react-redux + AsyncStorage = redux-persist

so inside createsotre file simply add these lines

store.subscribe(async()=> await AsyncStorage.setItem("store", JSON.stringify(store.getState())))

this will update the AsyncStorage whenever there are some changes in the redux store.

Then load the json converted store. when ever the app loads. and set the store again.

Because redux-persist creates issues when using wix react-native-navigation. If that's the case then I prefer to use simple redux with above subscriber function

How to create a hash or dictionary object in JavaScript

Don't use an array if you want named keys, use a plain object.

var a = {};
a["key1"] = "value1";
a["key2"] = "value2";

Then:

if ("key1" in a) {
   // something
} else {
   // something else 
}

handling dbnull data in vb.net

The only way that i know of is to test for it, you can do a combined if though to make it easy.

If NOT IsDbNull(myItem("sID")) AndAlso myItem("sID") = sId Then
   'Do success
ELSE
   'Failure
End If

I wrote in VB as that is what it looks like you need, even though you mixed languages.

Edit

Cleaned up to use IsDbNull to make it more readable

How to verify if nginx is running or not?

This is probably system-dependent, but this is the simplest way I've found.

if [ -e /var/run/nginx.pid ]; then echo "nginx is running"; fi

That's the best solution for scripting.

MySQL INNER JOIN Alias

You'll need to join twice:

SELECT home.*, away.*, g.network, g.date_start 
FROM game AS g
INNER JOIN team AS home
  ON home.importid = g.home
INNER JOIN team AS away
  ON away.importid = g.away
ORDER BY g.date_start DESC 
LIMIT 7

How to view transaction logs in SQL Server 2008

I accidentally deleted a whole bunch of data in the wrong environment and this post was one of the first ones I found.

Because I was simultaneously panicking and searching for a solution, I went for the first thing I saw - ApexSQL Logs, which was $2000 which was an acceptable cost.

However, I've since found out that Toad for Sql Server can generate undo scripts from transaction logs and it is only $655.

Lastly, found an even cheaper option SysToolsGroup Log Analyzer and it is only $300.

How to customize an end time for a YouTube video?

I just found out that the following works:

https://www.youtube.com/embed/[video_id]?start=[start_at_second]&end=[end_at_second]

Note: the time must be an integer number of seconds (e.g. 119, not 1m59s).

Changing the Git remote 'push to' default

Working with Git 2.3.2 ...

git branch --set-upstream-to myfork/master

Now status, push and pull are pointed to myfork remote

Installing Python packages from local file system folder to virtualenv with pip

To install only from local you need 2 options:

  • --find-links: where to look for dependencies. There is no need for the file:// prefix mentioned by others.
  • --no-index: do not look in pypi indexes for missing dependencies (dependencies not installed and not in the --find-links path).

So you could run from any folder the following:

pip install --no-index --find-links /srv/pkg /path/to/mypackage-0.1.0.tar.gz

If your mypackage is setup properly, it will list all its dependencies, and if you used pip download to download the cascade of dependencies (ie dependencies of depencies etc), everything will work.

If you want to use the pypi index if it is accessible, but fallback to local wheels if not, you can remove --no-index and add --retries 0. You will see pip pause for a bit while it is try to check pypi for a missing dependency (one not installed) and when it finds it cannot reach it, will fall back to local. There does not seem to be a way to tell pip to "look for local ones first, then the index".

What is the Git equivalent for revision number?

Git does not have the same concept of revision numbers as subversion. Instead each given snapshot made with a commit is tagged by a SHA1 checksum. Why? There are several problems with a running revno in a distributed version control system:

First, since development is not linear at all, the attachment of a number is rather hard as a problem to solve in a way which will satisfy your need as a programmer. Trying to fix this by adding a number might quickly become problematic when the number does not behave as you expect.

Second, revision numbers may be generated on different machines. This makes synchronization of numbers much harder - especially since connectivity is one-way; you may not even have access to all machines that has the repository.

Third, in git, somewhat pioneered by the now defunct OpenCM system, the identity of a commit (what the commit is) is equivalent to its name (the SHA id). This naming = identity concept is very strong. When you sit with a commit name in hand it also identifies the commit in an unforgeable way. This in turn lets you check all of your commits back to the first initial one for corruption with the git fsck command.

Now, since we have a DAG (Directed Acyclic Graph) of revisions and these constitute the current tree, we need some tools to solve your problem: How do we discriminate different versions. First, you can omit part of the hash if a given prefix, 1516bd say, uniquely identifies your commit. But this is also rather contrived. Instead, the trick is to use tags and or branches. A tag or branch is akin to a "yellow stick it note" you attach to a given commit SHA1-id. Tags are, in essence, meant to be non-moving whereas a branch will move when new commits are made to its HEAD. There are ways to refer to a commit around a tag or branch, see the man page of git-rev-parse.

Usually, if you need to work on a specific piece of code, that piece is undergoing changes and should as such be a branch with a saying topic name. Creating lots of branches (20-30 per programmer is not unheard of, with some 4-5 published for others to work on) is the trick for effective git. Every piece of work should start as its own branch and then be merged in when it is tested. Unpublished branches can be rewritten entirely and this part of destroying history is a force of git.

When the change is accepted into master it somewhat freezes and becomes archeology. At that point, you can tag it, but more often a reference to the particular commit is made in a bug tracker or issue tracker via the sha1 sum. Tags tend to be reserved for version bumps and branch points for maintenance branches (for old versions).

How to make input type= file Should accept only pdf and xls

You can try following way

<input type= "file" name="Upload" accept = "application/pdf,.csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel">

OR (in asp.net mvc)

@Html.TextBoxFor(x => x.FileName, new { @id = "doc", @type = "file", @accept = "application/pdf,.csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel" })

Peak memory usage of a linux/unix process

Please be sure to answer the question. Provide details and share your research!

Sorry, I am first time here and can only ask questions…

Used suggested:

valgrind --tool=massif --pages-as-heap=yes --massif-out-file=massif.out ./test.sh; grep mem_heap_B massif.out | sed -e 's/mem_heap_B=\(.*\)/\1/' | sort -g | tail -n 1

then:

grep mem_heap_B massif.out
...
mem_heap_B=1150976
mem_heap_B=1150976
...

this is very different from what top command shows at similar moment:

14673 gu27mox   20   0 3280404 468380  19176 R 100.0  2.9   6:08.84 pwanew_3pic_com

what are measured units from Valgrind??

The /usr/bin/time -v ./test.sh never answered — you must directly feed executable to /usr/bin/time like:

/usr/bin/time -v  pwanew_3pic_compass_2008florian3_dfunc.static  card_0.100-0.141_31212_resubmit1.dat_1.140_1.180   1.140 1.180 31212


    Command being timed: "pwanew_3pic_compass_2008florian3_dfunc.static card_0.100-0.141_31212_resubmit1.dat_1.140_1.180 1.140 1.180 31212"

    User time (seconds): 1468.44
    System time (seconds): 7.37
    Percent of CPU this job got: 99%
    Elapsed (wall clock) time (h:mm:ss or m:ss): 24:37.14
    Average shared text size (kbytes): 0
    Average unshared data size (kbytes): 0
    Average stack size (kbytes): 0
    Average total size (kbytes): 0
    Maximum resident set size (kbytes): 574844
    Average resident set size (kbytes): 0
    Major (requiring I/O) page faults: 74
    Minor (reclaiming a frame) page faults: 468880
    Voluntary context switches: 1190
    Involuntary context switches: 20534
    Swaps: 0
    File system inputs: 81128
    File system outputs: 1264
    Socket messages sent: 0
    Socket messages received: 0
    Signals delivered: 0
    Page size (bytes): 4096
    Exit status: 0

How to give a time delay of less than one second in excel vba?

You can use an API call and Sleep:

Put this at the top of your module:

Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

Then you can call it in a procedure like this:

Sub test()
Dim i As Long

For i = 1 To 10
    Debug.Print Now()
    Sleep 500    'wait 0.5 seconds
Next i
End Sub

How to use comparison operators like >, =, < on BigDecimal

BigDecimal isn't a primitive, so you cannot use the <, > operators. However, since it's a Comparable, you can use the compareTo(BigDecimal) to the same effect. E.g.:

public class Domain {
    private BigDecimal unitPrice;

    public boolean isCheaperThan(BigDecimal other) {
        return unitPirce.compareTo(other.unitPrice) < 0;
    }

    // etc...
}

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

Find end position of file:

f = open("file.txt","r")
f.seek(0,2) #Jumps to the end
f.tell()    #Give you the end location (characters from start)
f.seek(0)   #Jump to the beginning of the file again

Then you can to:

if line == '' and f.tell() == endLocation:
   break

Java, How do I get current index/key in "for each" loop

###################################################
###################################################
###################################################
AVOID THIS
###################################################
###################################################
###################################################

/*for (Song s: songList){
    System.out.println(s + "," + songList.indexOf(s); 
}*/

it is possible in linked list.

you have to make toString() in song class. if you don't it will print out reference of the song.

probably irrelevant for you by now. ^_^

How can I style the border and title bar of a window in WPF?

I found a more straight forward solution from @DK comment in this question, the solution is written by Alex and described here with source, To make customized window:

  1. download the sample project here
  2. edit the generic.xaml file to customize the layout.
  3. enjoy :).

Animate change of view background color on Android

I ended up figuring out a (pretty good) solution for this problem!

You can use a TransitionDrawable to accomplish this. For example, in an XML file in the drawable folder you could write something like:

<?xml version="1.0" encoding="UTF-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- The drawables used here can be solid colors, gradients, shapes, images, etc. -->
    <item android:drawable="@drawable/original_state" />
    <item android:drawable="@drawable/new_state" />
</transition>

Then, in your XML for the actual View you would reference this TransitionDrawable in the android:background attribute.

At this point you can initiate the transition in your code on-command by doing:

TransitionDrawable transition = (TransitionDrawable) viewObj.getBackground();
transition.startTransition(transitionTime);

Or run the transition in reverse by calling:

transition.reverseTransition(transitionTime);

See Roman's answer for another solution using the Property Animation API, which wasn't available at the time this answer was originally posted.

C++ String Concatenation operator<<

First of all it is unclear what type name has. If it has the type std::string then instead of

string nametext;
nametext = "Your name is" << name;

you should write

std::string nametext = "Your name is " + name;

where operator + serves to concatenate strings.

If name is a character array then you may not use operator + for two character arrays (the string literal is also a character array), because character arrays in expressions are implicitly converted to pointers by the compiler. In this case you could write

std::string nametext( "Your name is " );
nametext.append( name );

or

std::string nametext( "Your name is " );
nametext += name;

Determine what attributes were changed in Rails after_save callback?

you can add a condition to the after_update like so:

class SomeModel < ActiveRecord::Base
  after_update :send_notification, if: :published_changed?

  ...
end

there's no need to add a condition within the send_notification method itself.

laravel collection to array

Try this:

$comments_collection = $post->comments()->get()->toArray();

see this can help you
toArray() method in Collections

How to search a string in multiple files and return the names of files in Powershell?

There are a variety of accurate answers here, but here is the most concise code for several different variations. For each variation, the top line shows the full syntax and the bottom shows terse syntax.

Item (2) is a more concise form of the answers from Jon Z and manojlds, while item (1) is equivalent to the answers from vikas368 and buygrush.

  1. List FileInfo objects for all files containing pattern:

    Get-ChildItem -Recurse filespec | Where-Object { Select-String pattern $_ -Quiet }
    ls -r filespec | ? { sls pattern $_ -q }
    
  2. List file names for all files containing pattern:

    Get-ChildItem -Recurse filespec | Select-String pattern | Select-Object -Unique Path
    ls -r filespec | sls pattern | select -u Path
    
  3. List FileInfo objects for all files not containing pattern:

    Get-ChildItem -Recurse filespec | Where-Object { !(Select-String pattern $_ -Quiet) }
    ls -r filespec | ? { !(sls pattern $_ -q) }
    
  4. List file names for all files not containing pattern:

    (Get-ChildItem -Recurse filespec | Where-Object { !(Select-String pattern $_ -Quiet) }).FullName
    (ls -r filespec | ? { !(sls pattern $_ -q) }).FullName
    

Create <div> and append <div> dynamically

    while(i<10){
               $('#Postsoutput').prepend('<div id="first'+i+'">'+i+'</div>');
               /* get the dynamic Div*/
               $('#first'+i).hide(1000);
               $('#first'+i).show(1000);
                i++;
                }

eslint: error Parsing error: The keyword 'const' is reserved

you also can add this inline instead of config, just add it to the same file before you add your own disable stuff

/* eslint-env es6 */
/* eslint-disable no-console */

my case was disable a file and eslint-disable were not working for me alone

/* eslint-env es6 */
/* eslint-disable */

Making heatmap from pandas DataFrame

If you want an interactive heatmap from a Pandas DataFrame and you are running a Jupyter notebook, you can try the interactive Widget Clustergrammer-Widget, see interactive notebook on NBViewer here, documentation here

enter image description here

And for larger datasets you can try the in-development Clustergrammer2 WebGL widget (example notebook here)

How to join (merge) data frames (inner, outer, left, right)

I would recommend checking out Gabor Grothendieck's sqldf package, which allows you to express these operations in SQL.

library(sqldf)

## inner join
df3 <- sqldf("SELECT CustomerId, Product, State 
              FROM df1
              JOIN df2 USING(CustomerID)")

## left join (substitute 'right' for right join)
df4 <- sqldf("SELECT CustomerId, Product, State 
              FROM df1
              LEFT JOIN df2 USING(CustomerID)")

I find the SQL syntax to be simpler and more natural than its R equivalent (but this may just reflect my RDBMS bias).

See Gabor's sqldf GitHub for more information on joins.

WPF: simple TextBox data binding

Your Window is not implementing the necessary data binding notifications that the grid requires to use it as a data source, namely the INotifyPropertyChanged interface.

Your "Name2" string needs also to be a property and not a public variable, as data binding is for use with properties.

Implementing the necessary interfaces for using an object as a data source can be found here.

jQuery show/hide options from one select drop down, when option on other select dropdown is slected

And in 2016.....I do this (which works in all browsers and does not create "illegal" html).

For the drop-down select that is to show/hide different values add that value as a data attribute.

<select id="animal">
    <option value="1" selected="selected">Dog</option>
    <option value="2">Cat</option>
</select>
<select id="name">
    <option value=""></option>
    <option value="1" data-attribute="1">Rover</option>
    <option value="2" selected="selected" data-attribute="1">Lassie</option>
    <option value="3" data-attribute="1">Spot</option>
    <option value="4" data-attribute="2">Tiger</option>
    <option value="5" data-attribute="2">Fluffy</option>
</select>

Then in your jQuery add a change event to the first drop-down select to filter the second drop-down.

$("#animal").change( function() {
    filterSelectOptions($("#name"), "data-attribute", $(this).val());
});

And the magic part is this little jQuery utility.

function filterSelectOptions(selectElement, attributeName, attributeValue) {
    if (selectElement.data("currentFilter") != attributeValue) {
        selectElement.data("currentFilter", attributeValue);
        var originalHTML = selectElement.data("originalHTML");
        if (originalHTML)
            selectElement.html(originalHTML)
        else {
            var clone = selectElement.clone();
            clone.children("option[selected]").removeAttr("selected");
            selectElement.data("originalHTML", clone.html());
        }
        if (attributeValue) {
            selectElement.children("option:not([" + attributeName + "='" + attributeValue + "'],:not([" + attributeName + "]))").remove();
        }
    }
}

This little gem tracks the current filter, if different it restores the original select (all items) and then removes the filtered items. If the filter item is empty we see all items.

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

You might also consider removing the need for duplicated parameter names in your Sql by changing your Sql to

table.Variable2 LIKE '%' || :VarB || '%'

and then getting your client to provide '%' for any value of VarB instead of null. In some ways I think this is more natural.

You could also change the Sql to

table.Variable2 LIKE '%' || IfNull(:VarB, '%') || '%'

Rails 4: List of available datatypes

You might also find it useful to know generally what these data types are used for:

There's also references used to create associations. But, I'm not sure this is an actual data type.

New Rails 4 datatypes available in PostgreSQL:

  • :hstore - storing key/value pairs within a single value (learn more about this new data type)
  • :array - an arrangement of numbers or strings in a particular row (learn more about it and see examples)
  • :cidr_address - used for IPv4 or IPv6 host addresses
  • :inet_address - used for IPv4 or IPv6 host addresses, same as cidr_address but it also accepts values with nonzero bits to the right of the netmask
  • :mac_address - used for MAC host addresses

Learn more about the address datatypes here and here.

Also, here's the official guide on migrations: http://edgeguides.rubyonrails.org/migrations.html

Verify a method call using Moq

You're checking the wrong method. Moq requires that you Setup (and then optionally Verify) the method in the dependency class.

You should be doing something more like this:

class MyClassTest
{
    [TestMethod]
    public void MyMethodTest()
    {
        string action = "test";
        Mock<SomeClass> mockSomeClass = new Mock<SomeClass>();

        mockSomeClass.Setup(mock => mock.DoSomething());

        MyClass myClass = new MyClass(mockSomeClass.Object);
        myClass.MyMethod(action);

        // Explicitly verify each expectation...
        mockSomeClass.Verify(mock => mock.DoSomething(), Times.Once());

        // ...or verify everything.
        // mockSomeClass.VerifyAll();
    }
}

In other words, you are verifying that calling MyClass#MyMethod, your class will definitely call SomeClass#DoSomething once in that process. Note that you don't need the Times argument; I was just demonstrating its value.

C++ cast to derived class

Think like this:

class Animal { /* Some virtual members */ };
class Dog: public Animal {};
class Cat: public Animal {};


Dog     dog;
Cat     cat;
Animal& AnimalRef1 = dog;  // Notice no cast required. (Dogs and cats are animals).
Animal& AnimalRef2 = cat;
Animal* AnimalPtr1 = &dog;
Animal* AnimlaPtr2 = &cat;

Cat&    catRef1 = dynamic_cast<Cat&>(AnimalRef1);  // Throws an exception  AnimalRef1 is a dog
Cat*    catPtr1 = dynamic_cast<Cat*>(AnimalPtr1);  // Returns NULL         AnimalPtr1 is a dog
Cat&    catRef2 = dynamic_cast<Cat&>(AnimalRef2);  // Works
Cat*    catPtr2 = dynamic_cast<Cat*>(AnimalPtr2);  // Works

// This on the other hand makes no sense
// An animal object is not a cat. Therefore it can not be treated like a Cat.
Animal  a;
Cat&    catRef1 = dynamic_cast<Cat&>(a);    // Throws an exception  Its not a CAT
Cat*    catPtr1 = dynamic_cast<Cat*>(&a);   // Returns NULL         Its not a CAT.

Now looking back at your first statement:

Animal   animal = cat;    // This works. But it slices the cat part out and just
                          // assigns the animal part of the object.
Cat      bigCat = animal; // Makes no sense.
                          // An animal is not a cat!!!!!
Dog      bigDog = bigCat; // A cat is not a dog !!!!

You should very rarely ever need to use dynamic cast.
This is why we have virtual methods:

void makeNoise(Animal& animal)
{
     animal.DoNoiseMake();
}

Dog    dog;
Cat    cat;
Duck   duck;
Chicken chicken;

makeNoise(dog);
makeNoise(cat);
makeNoise(duck);
makeNoise(chicken);

The only reason I can think of is if you stored your object in a base class container:

std::vector<Animal*>  barnYard;
barnYard.push_back(&dog);
barnYard.push_back(&cat);
barnYard.push_back(&duck);
barnYard.push_back(&chicken);

Dog*  dog = dynamic_cast<Dog*>(barnYard[1]); // Note: NULL as this was the cat.

But if you need to cast particular objects back to Dogs then there is a fundamental problem in your design. You should be accessing properties via the virtual methods.

barnYard[1]->DoNoiseMake();

Refresh image with a new one at the same url

You can simply use fetch with the cache option set to 'reload' to update the cache:

fetch("my-image-url.jpg", {cache: 'reload', mode: 'no-cors'})

These days the fetch API is available almost everywhere (except on IE, of course).

As always you will find detailed information on how to use the fetch API on MDN.

Selecting a Linux I/O Scheduler

It's possible to use a udev rule to let the system decide on the scheduler based on some characteristics of the hw.
An example udev rule for SSDs and other non-rotational drives might look like

# set noop scheduler for non-rotating disks
ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="noop"

inside a new udev rules file (e.g., /etc/udev/rules.d/60-ssd-scheduler.rules). This answer is based on the debian wiki

To check whether ssd disks would use the rule, it's possible to check for the trigger attribute in advance:

for f in /sys/block/sd?/queue/rotational; do printf "$f "; cat $f; done

changing permission for files and folder recursively using shell command in mac

By using CHMOD yes:

For Recursive file:

chmod -R 777 foldername or pathname

For non recursive:

chmod 777 foldername or pathname

Select Pandas rows based on list index

There are many ways of solving this problem, and the ones listed above are the most commonly used ways of achieving the solution. I want to add two more ways, just in case someone is looking for an alternative.

index_list = [1,3]

df.take(pos)

#or

df.query('index in @index_list')

linux execute command remotely

I guess ssh is the best secured way for this, for example :

ssh -OPTIONS -p SSH_PORT user@remote_server "remote_command1; remote_command2; remote_script.sh"  

where the OPTIONS have to be deployed according to your specific needs (for example, binding to ipv4 only) and your remote command could be starting your tomcat daemon.

Note:
If you do not want to be prompt at every ssh run, please also have a look to ssh-agent, and optionally to keychain if your system allows it. Key is... to understand the ssh keys exchange process. Please take a careful look to ssh_config (i.e. the ssh client config file) and sshd_config (i.e. the ssh server config file). Configuration filenames depend on your system, anyway you'll find them somewhere like /etc/sshd_config. Ideally, pls do not run ssh as root obviously but as a specific user on both sides, servers and client.

Some extra docs over the source project main pages :

ssh and ssh-agent
man ssh

http://www.snailbook.com/index.html
https://help.ubuntu.com/community/SSH/OpenSSH/Configuring

keychain
http://www.gentoo.org/doc/en/keychain-guide.xml
an older tuto in French (by myself :-) but might be useful too :
http://hornetbzz.developpez.com/tutoriels/debian/ssh/keychain/

Invoke JSF managed bean action on page load

calling bean action from a will be a good idea,keep attribute autoRun="true" example below

<p:remoteCommand autoRun="true" name="myRemoteCommand" action="#{bean.action}" partialSubmit="true" update=":form" />

How can I undo a `git commit` locally and on a remote after `git push`

Try using

git reset --hard <commit id> 

Please Note : Here commit id will the id of the commit you want to go to but not the id you want to reset. this was the only point where i also got stucked.

then push

git push -f <remote> <branch>

How can I convert a timestamp from yyyy-MM-ddThh:mm:ss:SSSZ format to MM/dd/yyyy hh:mm:ss.SSS format? From ISO8601 to UTC

Hope this Helps:

public String getSystemTimeInBelowFormat() {
    String timestamp = new SimpleDateFormat("yyyy-mm-dd 'T' HH:MM:SS.mmm-HH:SS").format(new Date());
    return timestamp;
}

Kotlin Ternary Conditional Operator

Another interesting approach would be to use when:

when(a) {
  true -> b
  false -> c
}

Can be quite handy in some more complex scenarios. And honestly, it's more readable for me than if ... else ...

how to insert datetime into the SQL Database table?

DateTime values should be inserted as if they are strings surrounded by single quotes '20201231' but in many cases they need to be casted explicitly to datetime CAST(N'20201231' AS DATETIME) to avoid bad execution plans with CONVERSION_IMPLICIT warnings that affect negatively the performance. Hier is an example:

CREATE TABLE dbo.T(D DATETIME)

--wrong way
INSERT INTO dbo.T (D) VALUES ('20201231'), ('20201231')

Warnings in the execution plan

--better way
INSERT INTO dbo.T (D) VALUES (CAST(N'20201231' AS DATETIME)), (CAST(N'20201231' AS DATETIME))

No warnings

How to save S3 object to a file using boto3

# Preface: File is json with contents: {'name': 'Android', 'status': 'ERROR'}

import boto3
import io

s3 = boto3.resource('s3')

obj = s3.Object('my-bucket', 'key-to-file.json')
data = io.BytesIO()
obj.download_fileobj(data)

# object is now a bytes string, Converting it to a dict:
new_dict = json.loads(data.getvalue().decode("utf-8"))

print(new_dict['status']) 
# Should print "Error"

Python setup.py develop vs install

python setup.py install is used to install (typically third party) packages that you're not going to develop/modify/debug yourself.

For your own stuff, you want to first install your package and then be able to frequently edit the code without having to re-install the package every time — and that is exactly what python setup.py develop does: it installs the package (typically just a source folder) in a way that allows you to conveniently edit your code after it’s installed to the (virtual) environment, and have the changes take effect immediately.

Note that it is highly recommended to use pip install . (install) and pip install -e . (developer install) to install packages, as invoking setup.py directly will do the wrong things for many dependencies, such as pull prereleases and incompatible package versions, or make the package hard to uninstall with pip.

Linux - Install redis-cli only

In my case, I have to run some more steps to build it on RedHat or Centos.

# get system libraries
sudo yum install -y gcc wget

# get stable version and untar it
wget http://download.redis.io/redis-stable.tar.gz
tar xvzf redis-stable.tar.gz
cd redis-stable

# build dependencies too!
cd deps
make hiredis jemalloc linenoise lua geohash-int
cd ..

# compile it
make

# make it globally accesible
sudo cp src/redis-cli /usr/bin/

HTTP could not register URL http://+:8000/HelloWCF/. Your process does not have access rights to this namespace

Close iis express and all the browsers (if the url was opened in any of the browser). Also open the visual studio IDE in admin mode. This has resolved my issue.

How to return a resolved promise from an AngularJS Service using $q?

How to simply return a pre-resolved promise in AngularJS

Resolved promise:

return $q.when( someValue );    // angularjs 1.2+
return $q.resolve( someValue ); // angularjs 1.4+, alias to `when` to match ES6

Rejected promise:

return $q.reject( someValue );

Change hover color on a button with Bootstrap customization

I had to add !important to get it to work. I also made my own class button-primary-override.

.button-primary-override:hover, 
.button-primary-override:active,
.button-primary-override:focus,
.button-primary-override:visited{
    background-color: #42A5F5 !important;
    border-color: #42A5F5 !important;
    background-image: none !important;
    border: 0 !important;
}

Spring: How to inject a value to static field?

This is my sample code for load static variable

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class OnelinkConfig {
    public static int MODULE_CODE;
    public static int DEFAULT_PAGE;
    public static int DEFAULT_SIZE;

    @Autowired
    public void loadOnelinkConfig(@Value("${onelink.config.exception.module.code}") int code,
            @Value("${onelink.config.default.page}") int page, @Value("${onelink.config.default.size}") int size) {
        MODULE_CODE = code;
        DEFAULT_PAGE = page;
        DEFAULT_SIZE = size;
    }
}

How to add extension methods to Enums

All answers are great, but they are talking about adding extension method to a specific type of enum.

What if you want to add a method to all enums like returning an int of current value instead of explicit casting?

public static class EnumExtensions
{
    public static int ToInt<T>(this T soure) where T : IConvertible//enum
    {
        if (!typeof(T).IsEnum)
            throw new ArgumentException("T must be an enumerated type");

        return (int) (IConvertible) soure;
    }

    //ShawnFeatherly funtion (above answer) but as extention method
    public static int Count<T>(this T soure) where T : IConvertible//enum
    {
        if (!typeof(T).IsEnum)
            throw new ArgumentException("T must be an enumerated type");

        return Enum.GetNames(typeof(T)).Length;
    }
}

The trick behind IConvertible is its Inheritance Hierarchy see MDSN

Thanks to ShawnFeatherly for his answer

how to realize countifs function (excel) in R

library(matrixStats)
> data <- rbind(c("M", "F", "M"), c("Student", "Analyst", "Analyst"))
> rowCounts(data, value = 'M') # output = 2 0
> rowCounts(data, value = 'F') # output = 1 0

error: invalid type argument of ‘unary *’ (have ‘int’)

Once you declare the type of a variable, you don't need to cast it to that same type. So you can write a=&b;. Finally, you declared c incorrectly. Since you assign it to be the address of a, where a is a pointer to int, you must declare it to be a pointer to a pointer to int.

#include <stdio.h>
int main(void)
{
    int b=10;
    int *a=&b;
    int **c=&a;
    printf("%d", **c);
    return 0;
} 

Comparing two arrays & get the values which are not common

PS > $c = Compare-Object -ReferenceObject (1..5) -DifferenceObject (1..6) -PassThru
PS > $c
6

Instagram how to get my user id from username?

If you are using implicit Authentication must have the problem of not being able to find the user_id

I found a way for example:

Access Token = 1506417331.18b98f6.8a00c0d293624ded801d5c723a25d3ec the User id is 1506417331

would you do a split single seperated by . obtenies to acces token and the first element

Eclipse error: "Editor does not contain a main type"

Try closing and reopening the file, then press Ctrl+F11.

Verify that the name of the file you are running is the same as the name of the project you are working in, and that the name of the public class in that file is the same as the name of the project you are working in as well.

Otherwise, restart Eclipse. Let me know if this solves the problem! Otherwise, comment, and I'll try and help.

Apache Spark: map vs mapPartitions?

What's the difference between an RDD's map and mapPartitions method?

The method map converts each element of the source RDD into a single element of the result RDD by applying a function. mapPartitions converts each partition of the source RDD into multiple elements of the result (possibly none).

And does flatMap behave like map or like mapPartitions?

Neither, flatMap works on a single element (as map) and produces multiple elements of the result (as mapPartitions).

Symfony2 Setting a default choice field selection

From the docs:

public Form createNamed(string|FormTypeInterface $type, string $name, mixed $data = null, array $options = array())

mixed $data = null is the default options. So for example I have a field called status and I implemented it as so:

$default = array('Status' => 'pending');

$filter_form = $this->get('form.factory')->createNamedBuilder('filter', 'form', $default)
        ->add('Status', 'choice', array(
            'choices' => array(
                '' => 'Please Select...',
                'rejected' => 'Rejected',
                'incomplete' => 'Incomplete',
                'pending' => 'Pending',
                'approved' => 'Approved',
                'validated' => 'Validated',
                'processed' => 'Processed'
            )
        ))->getForm();

How to convert datetime to integer in python

When converting datetime to integers one must keep in mind the tens, hundreds and thousands.... like "2018-11-03" must be like 20181103 in int for that you have to 2018*10000 + 100* 11 + 3

Similarly another example, "2018-11-03 10:02:05" must be like 20181103100205 in int

Explanatory Code

dt = datetime(2018,11,3,10,2,5)
print (dt)

#print (dt.timestamp()) # unix representation ... not useful when converting to int

print (dt.strftime("%Y-%m-%d"))
print (dt.year*10000 + dt.month* 100  + dt.day)
print (int(dt.strftime("%Y%m%d")))

print (dt.strftime("%Y-%m-%d %H:%M:%S"))
print (dt.year*10000000000 + dt.month* 100000000 +dt.day * 1000000 + dt.hour*10000  +  dt.minute*100 + dt.second)
print (int(dt.strftime("%Y%m%d%H%M%S")))

General Function

To avoid that doing manually use below function

def datetime_to_int(dt):
    return int(dt.strftime("%Y%m%d%H%M%S"))

plot with custom text for x axis points

This worked for me. Each month on X axis

str_month_list = ['January','February','March','April','May','June','July','August','September','October','November','December']
ax.set_xticks(range(0,12))
ax.set_xticklabels(str_month_list)

Rename all files in a folder with a prefix in a single command

find -execdir rename

This renames files and directories with a regular expression affecting only basenames.

So for a prefix you could do:

PATH=/usr/bin find . -depth -execdir rename 's/^/Unix_/' '{}' \;

or to affect files only:

PATH=/usr/bin find . -type f -execdir rename 's/^/Unix_/' '{}' \;

-execdir first cds into the directory before executing only on the basename.

I have explained it in more detail at: Find multiple files and rename them in Linux

Create a nonclustered non-unique index within the CREATE TABLE statement with SQL Server

TLDR:

CREATE TABLE MyTable(
    a int NOT NULL
    ,b smallint NOT NULL index IX_indexName nonclustered
    ,c smallint NOT NULL
    ,d smallint NOT NULL
    ,e smallint NOT NULL
)

Details

As per T-SQL CREATE TABLE documentation, in 2014 the column definition supports defining an index:

<column_definition> ::=  
column_name <data_type>  
    ...
    [ <column_index> ]  

and <column_index> grammar is defined as:

<column_index> ::=   
 INDEX index_name [ CLUSTERED | NONCLUSTERED ]  
    [ WITH ( <index_option> [ ,... n ] ) ]  
    [ ON { partition_scheme_name (column_name )   
         | filegroup_name  
         | default   
         }  
    ]   
    [ FILESTREAM_ON { filestream_filegroup_name | partition_scheme_name | "NULL" } ]  
  

So a lot of what you can do as a separate statement can be done inline. I noticed include is not an option in this grammar so some things are not possible.

CREATE TABLE MyTable(
    a int NOT NULL
    ,b smallint NOT NULL index IX_indexName nonclustered
    ,c smallint NOT NULL
    ,d smallint NOT NULL
    ,e smallint NOT NULL
)

You can also have inline indexes defined as another line after columns, but within the create table statement, and this allows multiple columns in the index, but still no include clause:

< table_index > ::=   
{  
    {  
      INDEX index_name [ CLUSTERED | NONCLUSTERED ]   
         (column_name [ ASC | DESC ] [ ,... n ] )   
    | INDEX index_name CLUSTERED COLUMNSTORE  
    | INDEX index_name [ NONCLUSTERED ] COLUMNSTORE (column_name [ ,... n ] )  
    }  
    [ WITH ( <index_option> [ ,... n ] ) ]   
    [ ON { partition_scheme_name (column_name )   
         | filegroup_name  
         | default   
         }  
    ]   
    [ FILESTREAM_ON { filestream_filegroup_name | partition_scheme_name | "NULL" } ]  
  
}   

For example here we add an index on both columns c and d:

CREATE TABLE MyTable(
    a int NOT NULL
    ,b smallint NOT NULL index IX_MyTable_b nonclustered
    ,c smallint NOT NULL
    ,d smallint NOT NULL
    ,e smallint NOT NULL

    ,index IX_MyTable_c_d nonclustered (c,d)
)

Convert a timedelta to days, hours and minutes

I found the easiest way is using str(timedelta). It will return a sting formatted like 3 days, 21:06:40.001000, and you can parse hours and minutes using simple string operations or regular expression.

How to use HTML Agility pack

Main HTMLAgilityPack related code is as follows

using System;
using System.Net;
using System.Web;
using System.Web.Services;
using System.Web.Script.Services;
using System.Text.RegularExpressions;
using HtmlAgilityPack;

namespace GetMetaData
{
    /// <summary>
    /// Summary description for MetaDataWebService
    /// </summary>
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
    [System.Web.Script.Services.ScriptService]
    public class MetaDataWebService: System.Web.Services.WebService
    {
        [WebMethod]
        [ScriptMethod(UseHttpGet = false)]
        public MetaData GetMetaData(string url)
        {
            MetaData objMetaData = new MetaData();

            //Get Title
            WebClient client = new WebClient();
            string sourceUrl = client.DownloadString(url);

            objMetaData.PageTitle = Regex.Match(sourceUrl, @
            "\<title\b[^>]*\>\s*(?<Title>[\s\S]*?)\</title\>", RegexOptions.IgnoreCase).Groups["Title"].Value;

            //Method to get Meta Tags
            objMetaData.MetaDescription = GetMetaDescription(url);
            return objMetaData;
        }

        private string GetMetaDescription(string url)
        {
            string description = string.Empty;

            //Get Meta Tags
            var webGet = new HtmlWeb();
            var document = webGet.Load(url);
            var metaTags = document.DocumentNode.SelectNodes("//meta");

            if (metaTags != null)
            {
                foreach(var tag in metaTags)
                {
                    if (tag.Attributes["name"] != null && tag.Attributes["content"] != null && tag.Attributes["name"].Value.ToLower() == "description")
                    {
                        description = tag.Attributes["content"].Value;
                    }
                }
            } 
            else
            {
                description = string.Empty;
            }
            return description;
        }
    }
}

Using fonts with Rails asset pipeline

  1. If your Rails version is between > 3.1.0 and < 4, place your fonts in any of the these folders:

    • app/assets/fonts
    • lib/assets/fonts
    • vendor/assets/fonts


    For Rails versions > 4, you must place your fonts in the app/assets/fonts folder.

    Note: To place fonts outside of these designated folders, use the following configuration:

    config.assets.precompile << /\.(?:svg|eot|woff|ttf)\z/

    For Rails versions > 4.2, it is recommended to add this configuration to config/initializers/assets.rb.

    However, you can also add it to either config/application.rb , or to config/production.rb

  2. Declare your font in your CSS file:

    @font-face {
      font-family: 'Icomoon';
      src:url('icomoon.eot');
      src:url('icomoon.eot?#iefix') format('embedded-opentype'),
        url('icomoon.svg#icomoon') format('svg'),
        url('icomoon.woff') format('woff'),
        url('icomoon.ttf') format('truetype');
      font-weight: normal;
      font-style: normal;
    }
    

    Make sure your font is named exactly the same as in the URL portion of the declaration. Capital letters and punctuation marks matter. In this case, the font should have the name icomoon.

  3. If you are using Sass or Less with Rails > 3.1.0 (your CSS file has .scss or .less extension), then change the url(...) in the font declaration to font-url(...).

    Otherwise, your CSS file should have the extension .css.erb, and the font declaration should be url('<%= asset_path(...) %>').

    If you are using Rails > 3.2.1, you can use font_path(...) instead of asset_path(...). This helper does exactly the same thing but it's more clear.

  4. Finally, use your font in your CSS like you declared it in the font-family part. If it was declared capitalized, you can use it like this:

    font-family: 'Icomoon';
    

How to return a string value from a Bash function

You can echo a string, but catch it by piping (|) the function to something else.

You can do it with expr, though ShellCheck reports this usage as deprecated.

How to use "like" and "not like" in SQL MSAccess for the same field?

what's the problem with:

field like "*AA*" and field not like "*BB*"

it should be working.

Could you post some example of your data?

Warning: Attempt to present * on * whose view is not in the window hierarchy - swift

I was getting this error while was presenting controller after the user opens the deeplink. I know this isn't the best solution, but if you are in short time frame here is a quick fix - just wrap your code in asyncAfter:

DispatchQueue.main.asyncAfter(deadline: .now() + 0.7, execute: { [weak self] in
                                navigationController.present(signInCoordinator.baseController, animated: animated, completion: completion)
                            })

It will give time for your presenting controller to call viewDidAppear.

How to fix the Hibernate "object references an unsaved transient instance - save the transient instance before flushing" error

One possible cause of the error is the inexistence of the setting of the value of the parent entity ; for example for a department-employees relationship you have to write this in order to fix the error :

Department dept = (Department)session.load(Department.class, dept_code); // dept_code is from the jsp form which you get in the controller with @RequestParam String department
employee.setDepartment(dept);

Upload file to SFTP using PowerShell

You didn't tell us what particular problem do you have with the WinSCP, so I can really only repeat what's in WinSCP documentation.

  • Download WinSCP .NET assembly.
    The latest package as of now is WinSCP-5.17.10-Automation.zip;

  • Extract the .zip archive along your script;

  • Use a code like this (based on the official PowerShell upload example):

      # Load WinSCP .NET assembly
      Add-Type -Path "WinSCPnet.dll"
    
      # Setup session options
      $sessionOptions = New-Object WinSCP.SessionOptions -Property @{
          Protocol = [WinSCP.Protocol]::Sftp
          HostName = "example.com"
          UserName = "user"
          Password = "mypassword"
          SshHostKeyFingerprint = "ssh-rsa 2048 xxxxxxxxxxx...="
      }
    
      $session = New-Object WinSCP.Session
    
      try
      {
          # Connect
          $session.Open($sessionOptions)
    
          # Upload
          $session.PutFiles("C:\FileDump\export.txt", "/Outbox/").Check()
      }
      finally
      {
          # Disconnect, clean up
          $session.Dispose()
      }
    

You can have WinSCP generate the PowerShell script for the upload for you:

  • Login to your server with WinSCP GUI;
  • Navigate to the target directory in the remote file panel;
  • Select the file for upload in the local file panel;
  • Invoke the Upload command;
  • On the Transfer options dialog, go to Transfer Settings > Generate Code;
  • On the Generate transfer code dialog, select the .NET assembly code tab;
  • Choose PowerShell language.

You will get a code like above with all session and transfer settings filled in.

Generate transfer code dialog

(I'm the author of WinSCP)

How to add a single item to a Pandas Series

TLDR: do not append items to a series one by one, better extend with an ordered collection

I think the question in its current form is a bit tricky. And the accepted answer does answer the question. But the more I use pandas, the more I understand that it's a bad idea to append items to a Series one by one. I'll try to explain why for pandas beginners.

You might think that appending data to a given Series might allow you to reuse some resources, but in reality a Series is just a container that stores a relation between an index and a values array. Each is a numpy.array under the hood, and the index is immutable. When you add to Series an item with a label that is missing in the index, a new index with size n+1 is created, and a new values values array of the same size. That means that when you append items one by one, you create two more arrays of the n+1 size on each step.

By the way, you can not append a new item by position (you will get an IndexError) and the label in an index does not have to be unique, that is when you assign a value with a label, you assign the value to all existing items with the the label, and a new row is not appended in this case. This might lead to subtle bugs.

The moral of the story is that you should not append data one by one, you should better extend with an ordered collection. The problem is that you can not extend a Series inplace. That is why it is better to organize your code so that you don't need to update a specific instance of a Series by reference.

If you create labels yourself and they are increasing, the easiest way is to add new items to a dictionary, then create a new Series from the dictionary (it sorts the keys) and append the Series to an old one. If the keys are not increasing, then you will need to create two separate lists for the new labels and the new values.

Below are some code samples:

In [1]: import pandas as pd
In [2]: import numpy as np

In [3]: s = pd.Series(np.arange(4)**2, index=np.arange(4))

In [4]: s
Out[4]:
0    0
1    1
2    4
3    9
dtype: int64

In [6]: id(s.index), id(s.values)
Out[6]: (4470549648, 4470593296)

When we update an existing item, the index and the values array stay the same (if you do not change the type of the value)

In [7]: s[2] = 14  

In [8]: id(s.index), id(s.values)
Out[8]: (4470549648, 4470593296)

But when you add a new item, a new index and a new values array is generated:

In [9]: s[4] = 16

In [10]: s
Out[10]:
0     0
1     1
2    14
3     9
4    16
dtype: int64

In [11]: id(s.index), id(s.values)
Out[11]: (4470548560, 4470595056)

That is if you are going to append several items, collect them in a dictionary, create a Series, append it to the old one and save the result:

In [13]: new_items = {item: item**2 for item in range(5, 7)}

In [14]: s2 = pd.Series(new_items)

In [15]: s2  # keys are guaranteed to be sorted!
Out[15]:
5    25
6    36
dtype: int64

In [16]: s = s.append(s2); s
Out[16]:
0     0
1     1
2    14
3     9
4    16
5    25
6    36
dtype: int64

How to fetch JSON file in Angular 2

service.service.ts
--------------------------------------------------------------

import { Injectable } from '@angular/core';
import { Http,Response} from '@angular/http';
import { Observable } from 'rxjs';
import 'rxjs/add/operator/map';

@Injectable({
  providedIn: 'root'
})
export class ServiceService {
 private url="some URL";

constructor(private http:Http) { }     

//getData() is a method to fetch the data from web api or json file

getData(){
           getData(){
          return this.http.get(this.url)
            .map((response:Response)=>response.json())
        }
          }
}






display.component.ts
--------------------------------------------

//In this component get the data using suscribe() and store it in local object as dataObject and display the data in display.component.html like {{dataObject .propertyName}}.

import { Component, OnInit } from '@angular/core';
import { ServiceService } from 'src/app/service.service';

@Component({
  selector: 'app-display',
  templateUrl: './display.component.html',
  styleUrls: ['./display.component.css']
})
export class DisplayComponent implements OnInit {
      dataObject :any={};
constructor(private service:ServiceService) { }

  ngOnInit() {
    this.service.getData()
      .subscribe(resData=>this.dataObject =resData)
}
}

How to run ~/.bash_profile in mac terminal

On MacOS: add source ~/.bash_profile to the end of ~/.zshrc. Then this profile will be in effect when you open zsh.

How to delete an item in a list if it exists?

All you have to do is this

list = ["a", "b", "c"]
    try:
        list.remove("a")
    except:
        print("meow")

but that method has an issue. You have to put something in the except place so i found this:

list = ["a", "b", "c"]
if "a" in str(list):
    list.remove("a")

How to make a div 100% height of the browser window

You can use vh in this case which is relative to 1% of the height of the viewport...

That means if you want to cover off the height, just simply use 100vh.

Look at the image below I draw for you here:

How to make a div 100% height of the browser window?

Try the snippet I created for you as below:

_x000D_
_x000D_
.left {_x000D_
  height: 100vh;_x000D_
  width: 50%;_x000D_
  background-color: grey;_x000D_
  float: left;_x000D_
}_x000D_
_x000D_
.right {_x000D_
  height: 100vh;_x000D_
  width: 50%;_x000D_
  background-color: red;_x000D_
  float: right;_x000D_
}
_x000D_
<div class="left"></div>_x000D_
<div class="right"></div>
_x000D_
_x000D_
_x000D_

Count number of records returned by group by

The simplest solution is to use a derived table:

Select Count(*)
From    (
        Select ...
        From TempTable
        Group By column_1, column_2, column_3, column_4
        ) As Z

Another solution is to use a Count Distinct:

Select ...
    , ( Select Count( Distinct column_1, column_2, column_3, column_4 )
        From TempTable ) As CountOfItems
From TempTable
Group By column_1, column_2, column_3, column_4

To draw an Underline below the TextView in Android

In Kotlin you can create extension property:

inline var TextView.underline: Boolean
    set(visible) {
        paintFlags = if (visible) paintFlags or Paint.UNDERLINE_TEXT_FLAG
        else paintFlags and Paint.UNDERLINE_TEXT_FLAG.inv()
    }
    get() = paintFlags and Paint.UNDERLINE_TEXT_FLAG == Paint.UNDERLINE_TEXT_FLAG

And use:

textView.underline = true

Get value when selected ng-option changes

I had the same issue and found a unique solution. This is not best practice, but it may prove simple/helpful for someone. Just use jquery on the id or class or your select tag and you then have access to both the text and the value in the change function. In my case I'm passing in option values via sails/ejs:

    <select id="projectSelector" class="form-control" ng-model="ticket.project.id" ng-change="projectChange(ticket)">
      <% _.each(projects, function(project) { %>
        <option value="<%= project.id %>"><%= project.title %></option>
        <% }) %>
    </select>

Then in my Angular controller my ng-change function looks like this:

    $scope.projectChange = function($scope) {
         $scope.project.title=$("#projectSelector option:selected").text();
     };

get current page from url

Path.GetFileName( Request.Url.AbsolutePath )

jQuery.getJSON - Access-Control-Allow-Origin Issue

It's simple, use $.getJSON() function and in your URL just include

callback=?

as a parameter. That will convert the call to JSONP which is necessary to make cross-domain calls. More info: http://api.jquery.com/jQuery.getJSON/

Stored procedure - return identity as output parameter or scalar

I prefer to return the identity value as an output parameter. The result of the SP should indicate whether it succeeded or not. A value of 0 indicates the SP successfully completed, a non-zero value indicates an error. Also, if you ever need to make a change and return an additional value from the SP you don't need to make any changes other than adding an additional output parameter.

How to split a string in Ruby and get all items except the first one?

ex="test1,test2,test3,test4,test5"
all_but_first=ex.split(/,/)[1..-1]

Python copy files to a new directory and rename if file name already exists

Sometimes it is just easier to start over... I apologize if there is any typo, I haven't had the time to test it thoroughly.

movdir = r"C:\Scans"
basedir = r"C:\Links"
# Walk through all files in the directory that contains the files to copy
for root, dirs, files in os.walk(movdir):
    for filename in files:
        # I use absolute path, case you want to move several dirs.
        old_name = os.path.join( os.path.abspath(root), filename )

        # Separate base from extension
        base, extension = os.path.splitext(filename)

        # Initial new name
        new_name = os.path.join(basedir, base, filename)

        # If folder basedir/base does not exist... You don't want to create it?
        if not os.path.exists(os.path.join(basedir, base)):
            print os.path.join(basedir,base), "not found" 
            continue    # Next filename
        elif not os.path.exists(new_name):  # folder exists, file does not
            shutil.copy(old_name, new_name)
        else:  # folder exists, file exists as well
            ii = 1
            while True:
                new_name = os.path.join(basedir,base, base + "_" + str(ii) + extension)
                if not os.path.exists(new_name):
                   shutil.copy(old_name, new_name)
                   print "Copied", old_name, "as", new_name
                   break 
                ii += 1

How to convert characters to HTML entities using plain JavaScript

Best solution is posted at phpjs.org implementation of PHP function htmlentities

The format is htmlentities(string, quote_style, charset, double_encode) Full documentation on the PHP function which is identical can be read here

How to pass 2D array (matrix) in a function in C?

2D array:

int sum(int array[][COLS], int rows)
{

}

3D array:

int sum(int array[][B][C], int A)
{

}

4D array:

int sum(int array[][B][C][D], int A)
{

}

and nD array:

int sum(int ar[][B][C][D][E][F].....[N], int A)
{

}

How to solve maven 2.6 resource plugin dependency?

I have faced the same issue. Try declaring missing plugin in the conf/settings.xml.

<build>
    <pluginManagement>
      <plugins>
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>2.6</version>
        </plugin>           
      </plugins>
    </pluginManagement>   
</build>

How to parse JSON array in jQuery?

I am trying to parse JSON data returned from an ajax call, and the following is working for me:

Sample PHP code

$portfolio_array= Array('desc'=>'This is test description1','item1'=>'1.jpg','item2'=>'2.jpg');

echo json_encode($portfolio_array);

And in the .js, i am parsing like this:

var req=$.post("json.php", { id: "" + id + ""},
function(data) {
    data=$.parseJSON(data);
    alert(data.desc);
    $.each(data, function(i,item){
    alert(item);
    });
})
.success(function(){})
.error(function(){alert('There was problem loading portfolio details.');})
.complete(function(){});

If you have multidimensional array like below

$portfolio_array= Array('desc'=>'This is test description 1','items'=> array('item1'=>'1.jpg','item2'=>'2.jpg'));
echo json_encode($portfolio_array);

Then the code below should work:

var req=$.post("json.php", { id: "" + id + 
    function(data) {
    data=$.parseJSON(data);
    alert(data.desc);
    $.each(data.items, function(i,item){
    alert(item);
    });
})
.success(function(){})
.error(function(){alert('There was problem loading portfolio details.');})
.complete(function(){});

Please note the sub array key here is items, and suppose if you have xyz then in place of data.items use data.xyz

Import local function from a module housed in another directory with relative imports in Jupyter Notebook using Python 3

I had almost the same example as you in this notebook where I wanted to illustrate the usage of an adjacent module's function in a DRY manner.

My solution was to tell Python of that additional module import path by adding a snippet like this one to the notebook:

import os
import sys
module_path = os.path.abspath(os.path.join('..'))
if module_path not in sys.path:
    sys.path.append(module_path)

This allows you to import the desired function from the module hierarchy:

from project1.lib.module import function
# use the function normally
function(...)

Note that it is necessary to add empty __init__.py files to project1/ and lib/ folders if you don't have them already.

How do I set up Android Studio to work completely offline?

It seems as though gradle was not installed for me. Going to Android/Sdk/tools/templates/gradle/wrapper and running ./gradlew tasks --debug has resulted in it downloading.

What does $1 [QSA,L] mean in my .htaccess file?

This will capture requests for files like version, release, and README.md, etc. which should be treated either as endpoints, if defined (as in the case of /release), or as "not found."

How do I include a Perl module that's in a different directory?

From perlfaq8:


How do I add the directory my program lives in to the module/library search path?

(contributed by brian d foy)

If you know the directory already, you can add it to @INC as you would for any other directory. You might use lib if you know the directory at compile time:

use lib $directory;

The trick in this task is to find the directory. Before your script does anything else (such as a chdir), you can get the current working directory with the Cwd module, which comes with Perl:

BEGIN {
    use Cwd;
    our $directory = cwd;
    }

use lib $directory;

You can do a similar thing with the value of $0, which holds the script name. That might hold a relative path, but rel2abs can turn it into an absolute path. Once you have the

BEGIN {
    use File::Spec::Functions qw(rel2abs);
    use File::Basename qw(dirname);

    my $path   = rel2abs( $0 );
    our $directory = dirname( $path );
    }

use lib $directory;

The FindBin module, which comes with Perl, might work. It finds the directory of the currently running script and puts it in $Bin, which you can then use to construct the right library path:

use FindBin qw($Bin);

How to get parameters from the URL with JSP

request.getParameter("accountID") is what you're looking for. This is part of the Java Servlet API. See http://java.sun.com/j2ee/sdk_1.3/techdocs/api/javax/servlet/ServletRequest.html for more information.

jQuery check if Cookie exists, if not create it

I was having alot of trouble with this because I was using:

if($.cookie('token') === null || $.cookie('token') === "")
{
      //no cookie
}
else
{
     //have cookie
}

The above was ALWAYS returning false, no matter what I did in terms of setting the cookie or not. From my tests it seems that the object is therefore undefined before it's set so adding the following to my code fixed it.

if($.cookie('token') === null || $.cookie('token') === "" 
    || $.(cookie('token') === "null" || $.cookie('token') === undefined)
{
      //no cookie
}
else
{
     //have cookie
}

Arduino Sketch upload issue - avrdude: stk500_recv(): programmer is not responding

This combination of the above answers solved the problem for me:

  • performed the Java update:

    sudo apt-get install default-jdk

  • then killed the Arduino IDE and restarted it

  • my correct board now showed up (Arduino Mega 2560, where before Mega 1280 was only option)

  • for the drivers, I did this:

    sudo chmod a+rw /dev/serial/by-id/usb-Arduino__www.arduino.cc__(a bunch of numbers)

After that, my Arduino IDE shows /dev/ttyACM0 in the tools/serial port menu.

Now, everything works great!

Using python PIL to turn a RGB image into a pure black and white image

A PIL only solution for creating a bi-level (black and white) image with a custom threshold:

from PIL import Image
img = Image.open('mB96s.png')
thresh = 200
fn = lambda x : 255 if x > thresh else 0
r = img.convert('L').point(fn, mode='1')
r.save('foo.png')

With just

r = img.convert('1')
r.save('foo.png')

you get a dithered image.

From left to right the input image, the black and white conversion result and the dithered result:

Input Image Black and White Result Dithered Result

You can click on the images to view the unscaled versions.

Adding an arbitrary line to a matplotlib plot in ipython notebook

You can directly plot the lines you want by feeding the plot command with the corresponding data (boundaries of the segments):

plot([x1, x2], [y1, y2], color='k', linestyle='-', linewidth=2)

(of course you can choose the color, line width, line style, etc.)

From your example:

import numpy as np
import matplotlib.pyplot as plt

np.random.seed(5)
x = np.arange(1, 101)
y = 20 + 3 * x + np.random.normal(0, 60, 100)
plt.plot(x, y, "o")


# draw vertical line from (70,100) to (70, 250)
plt.plot([70, 70], [100, 250], 'k-', lw=2)

# draw diagonal line from (70, 90) to (90, 200)
plt.plot([70, 90], [90, 200], 'k-')

plt.show()

new chart

Struct Constructor in C++?

Syntax is as same as of class in C++. If you aware of creating constructor in c++ then it is same in struct.

struct Date
{
    int day;

    Date(int d)
    {
        day = d;
    }

    void printDay()
    {
        cout << "day " << day << endl;
    }
};

Struct can have all things as class in c++. As earlier said difference is only that by default C++ member have private access but in struct it is public.But as per programming consideration Use the struct keyword for data-only structures. Use the class keyword for objects that have both data and functions.

getting error HTTP Status 405 - HTTP method GET is not supported by this URL but not used `get` ever?

I think your issue may be in the url pattern. Changing

<servlet-mapping>
    <servlet-name>Register</servlet-name>
    <url-pattern>/Register</url-pattern>
</servlet-mapping>

and

<form action="/Register" method="post">

may fix your problem

How do you set the document title in React?

You can use the following below with document.title = 'Home Page'

import React from 'react'
import { Component } from 'react-dom'


class App extends Component{
  componentDidMount(){
    document.title = "Home Page"
  }

  render(){
    return(
      <p> Title is now equal to Home Page </p>
    )
  }
}

ReactDOM.render(
  <App />,
  document.getElementById('root')
);

or You can use this npm package npm i react-document-title

import React from 'react'
import { Component } from 'react-dom'
import DocumentTitle from 'react-document-title';


class App extends Component{


  render(){
    return(
      <DocumentTitle title='Home'>
        <h1>Home, sweet home.</h1>
      </DocumentTitle>
    )
  }
}

ReactDOM.render(
  <App />,
  document.getElementById('root')
);

Happy Coding!!!

React - uncaught TypeError: Cannot read property 'setState' of undefined

if your are using ES5 syntax then you need to bind it properly

this.delta = this.delta.bind(this)

and if you are using ES6 and above you can use arrow function, then you don't need to use bind() it

delta = () => {
    // do something
  }

Unit tests vs Functional tests

The basic distinction, though, is that functional tests test the application from the outside, from the point of view of the user. Unit tests test the application from the inside, from the point of view of the programmer. Functional tests should help you build an application with the right functionality, and guarantee you never accidentally break it. Unit tests should help you to write code that’s clean and bug free.

Taken from "Python TDD" book by Harry Percival

Getting first and last day of the current month

var now = DateTime.Now;
var first = new DateTime(now.Year, now.Month, 1);
var last = first.AddMonths(1).AddDays(-1);

You could also use DateTime.DaysInMonth method:

var last = new DateTime(now.Year, now.Month, DateTime.DaysInMonth(now.Year, now.Month));

How do I encode and decode a base64 string?

You can display it like this:

var strOriginal = richTextBox1.Text;

byte[] byt = System.Text.Encoding.ASCII.GetBytes(strOriginal);

// convert the byte array to a Base64 string
string strModified = Convert.ToBase64String(byt);

richTextBox1.Text = "" + strModified;

Now, converting it back.

var base64EncodedBytes = System.Convert.FromBase64String(richTextBox1.Text);

richTextBox1.Text = "" + System.Text.Encoding.ASCII.GetString(base64EncodedBytes);
MessageBox.Show("Done Converting! (ASCII from base64)");

I hope this helps!

Clone only one branch

I have done with below single git command:

git clone [url] -b [branch-name] --single-branch

JavaScript/jQuery - How to check if a string contain specific words

You might wanna use include method in JS.

var sentence = "This is my line";
console.log(sentence.includes("my"));
//returns true if substring is present.

PS: includes is case sensitive.

python, sort descending dataframe with pandas

For pandas 0.17 and above, use this :

test = df.sort_values('one', ascending=False)

Since 'one' is a series in the pandas data frame, hence pandas will not accept the arguments in the form of a list.

Android Studio Stuck at Gradle Download on create new project

Solution :

1). Delete the C:\Users\username.gradle folder

2). Download http://downloads.gradle.org/distributions/gradle-2.2.1-all.zip

3). Create a new project in android studio.

4). When this time it stucks at gradle building, Force close the android studio.

5) Now go to C:\Users\username.gradle\wrapper\dists\gradle-2.2.1-all\c64ydeuardnfqctvr1gm30w53 (the end directory name may be different)

6) Delete gradle-2.2.1-all.zip.lck and other files from this directory.

7) Paste the new downloaded gradle-2.2.1-all.zip here.

8) Run the android studio. :)

How to check if element is visible after scrolling?

The only plugin which works consistently for me for doing this, is: https://github.com/customd/jquery-visible

I ported this plugin to GWT recently since I didn't want to add jquery as a dependency just for using the plugin. Here's my (simple) port (just including the functionality that I need for my use case):

public static boolean isVisible(Element e)
{
    //vp = viewPort, b = bottom, l = left, t = top, r = right
    int vpWidth   = Window.getClientWidth();
    int vpHeight = Window.getClientHeight();


    boolean tViz = ( e.getAbsoluteTop() >= 0 && e.getAbsoluteTop()<  vpHeight);
    boolean bViz = (e.getAbsoluteBottom() >  0 && e.getAbsoluteBottom() <= vpHeight);
    boolean lViz = (e.getAbsoluteLeft() >= 0 && e.getAbsoluteLeft() < vpWidth);
    boolean rViz = (e.getAbsoluteRight()  >  0 && e.getAbsoluteRight()  <= vpWidth);

    boolean vVisible   = tViz && bViz;
    boolean hVisible   = lViz && rViz;

    return hVisible && vVisible;
}

Where/how can I download (and install) the Microsoft.Jet.OLEDB.4.0 for Windows 8, 64 bit?

Make sure to target x86 on your project in Visual Studio. This should fix your trouble.

How to find a string inside a entire database?

I usually use information_Schema.columns and information_schema.tables, although like @yuck said, sys.tables and sys.columns are shorter to type.

In a loop, concatenate these

@sql = @sql + 'select' + column_name + 
' from ' + table_name + 
' where ' + column_name ' like ''%''+value+''%' UNION

Then execute the resulting sql.

Is there a Max function in SQL Server that takes two values like Math.Max in .NET?

SELECT o.OrderID
CASE WHEN o.NegotiatedPrice > o.SuggestedPrice THEN
 o.NegotiatedPrice
ELSE
 o.SuggestedPrice
END AS Price

How to create and download a csv file from php script?

That is the function that I used for my project, and it works as expected.

function array_csv_download( $array, $filename = "export.csv", $delimiter=";" )
{
    header( 'Content-Type: application/csv' );
    header( 'Content-Disposition: attachment; filename="' . $filename . '";' );

    // clean output buffer
    ob_end_clean();

    $handle = fopen( 'php://output', 'w' );

    // use keys as column titles
    fputcsv( $handle, array_keys( $array['0'] ) );

    foreach ( $array as $value ) {
        fputcsv( $handle, $value , $delimiter );
    }

    fclose( $handle );

    // flush buffer
    ob_flush();

    // use exit to get rid of unexpected output afterward
    exit();
}

Exception thrown in catch and finally clause

Exceptions in the finally block supersede exceptions in the catch block.

Java Language Specification:

If the catch block completes abruptly for reason R, then the finally block is executed. Then there is a choice:

  • If the finally block completes normally, then the try statement completes abruptly for reason R.

  • If the finally block completes abruptly for reason S, then the try statement completes abruptly for reason S (and reason R is discarded).

How to split a String by space

Try this one

    String str = "This is String";
    String[] splited = str.split("\\s+");

    String split_one=splited[0];
    String split_second=splited[1];
    String split_three=splited[2];

   Log.d("Splited String ", "Splited String" + split_one+split_second+split_three);

How to connect mySQL database using C++

Finally I could successfully compile a program with C++ connector in Ubuntu 12.04 I have installed the connector using this command

'apt-get install libmysqlcppconn-dev'

Initially I faced the same problem with "undefined reference to `get_driver_instance' " to solve this I declare my driver instance variable of MySQL_Driver type. For ready reference this type is defined in mysql_driver.h file. Here is the code snippet I used in my program.

sql::mysql::MySQL_Driver *driver;
try {     
    driver = sql::mysql::get_driver_instance();
}

and I compiled the program with -l mysqlcppconn linker option

and don't forget to include this header

#include "mysql_driver.h" 

Could not reliably determine the server's fully qualified domain name

  1. sudo vim /etc/apache2/httpd.conf
  2. Insert the following line at the httpd.conf: ServerName localhost
  3. Just restart the Apache: sudo /etc/init.d/apache2 restart

How to prevent rm from reporting that a file was not found?

The main use of -f is to force the removal of files that would not be removed using rm by itself (as a special case, it "removes" non-existent files, thus suppressing the error message).

You can also just redirect the error message using

$ rm file.txt 2> /dev/null

(or your operating system's equivalent). You can check the value of $? immediately after calling rm to see if a file was actually removed or not.

list all files in the folder and also sub folders

You can return a List instead of an array and things gets much simpler.

    public static List<File> listf(String directoryName) {
        File directory = new File(directoryName);

        List<File> resultList = new ArrayList<File>();

        // get all the files from a directory
        File[] fList = directory.listFiles();
        resultList.addAll(Arrays.asList(fList));
        for (File file : fList) {
            if (file.isFile()) {
                System.out.println(file.getAbsolutePath());
            } else if (file.isDirectory()) {
                resultList.addAll(listf(file.getAbsolutePath()));
            }
        }
        //System.out.println(fList);
        return resultList;
    } 

How do I get the last character of a string?

The code:

public class Test {
    public static void main(String args[]) {
        String string = args[0];
        System.out.println("last character: " +
                           string.substring(string.length() - 1)); 
    }
}

The output of java Test abcdef:

last character: f

How to insert element into arrays at specific position?

This function supports:

  • both numeric and assoc keys
  • insert before or after the founded key
  • append to the end of array if key isn't founded

function insert_into_array( $array, $search_key, $insert_key, $insert_value, $insert_after_founded_key = true, $append_if_not_found = false ) {

        $new_array = array();

        foreach( $array as $key => $value ){

            // INSERT BEFORE THE CURRENT KEY? 
            // ONLY IF CURRENT KEY IS THE KEY WE ARE SEARCHING FOR, AND WE WANT TO INSERT BEFORE THAT FOUNDED KEY
            if( $key === $search_key && ! $insert_after_founded_key )
                $new_array[ $insert_key ] = $insert_value;

            // COPY THE CURRENT KEY/VALUE FROM OLD ARRAY TO A NEW ARRAY
            $new_array[ $key ] = $value;

            // INSERT AFTER THE CURRENT KEY? 
            // ONLY IF CURRENT KEY IS THE KEY WE ARE SEARCHING FOR, AND WE WANT TO INSERT AFTER THAT FOUNDED KEY
            if( $key === $search_key && $insert_after_founded_key )
                $new_array[ $insert_key ] = $insert_value;

        }

        // APPEND IF KEY ISNT FOUNDED
        if( $append_if_not_found && count( $array ) == count( $new_array ) )
            $new_array[ $insert_key ] = $insert_value;

        return $new_array;

    }

USAGE:

    $array1 = array(
        0 => 'zero',
        1 => 'one',
        2 => 'two',
        3 => 'three',
        4 => 'four'
    );

    $array2 = array(
        'zero'  => '# 0',
        'one'   => '# 1',
        'two'   => '# 2',
        'three' => '# 3',
        'four'  => '# 4'
    );

    $array3 = array(
        0 => 'zero',
        1 => 'one',
       64 => '64',
        3 => 'three',
        4 => 'four'
    );


    // INSERT AFTER WITH NUMERIC KEYS
    print_r( insert_into_array( $array1, 3, 'three+', 'three+ value') );

    // INSERT AFTER WITH ASSOC KEYS
    print_r( insert_into_array( $array2, 'three', 'three+', 'three+ value') );

    // INSERT BEFORE
    print_r( insert_into_array( $array3, 64, 'before-64', 'before-64 value', false) );

    // APPEND IF SEARCH KEY ISNT FOUNDED
    print_r( insert_into_array( $array3, 'undefined assoc key', 'new key', 'new value', true, true) );

RESULTS:

Array
(
    [0] => zero
    [1] => one
    [2] => two
    [3] => three
    [three+] => three+ value
    [4] => four
)
Array
(
    [zero] => # 0
    [one] => # 1
    [two] => # 2
    [three] => # 3
    [three+] => three+ value
    [four] => # 4
)
Array
(
    [0] => zero
    [1] => one
    [before-64] => before-64 value
    [64] => 64
    [3] => three
    [4] => four
)
Array
(
    [0] => zero
    [1] => one
    [64] => 64
    [3] => three
    [4] => four
    [new key] => new value
)

Spring 3 MVC accessing HttpRequest from controller

I know that is a old question, but...

You can also use this in your class:

@Autowired
private HttpServletRequest context;

And this will provide the current instance of HttpServletRequest for you use on your method.

Exception: Unexpected end of ZLIB input stream

You have to call close() on the GZIPOutputStream before you attempt to read it. The final bytes of the file will only be written when the file is actually closed. (This is irrespective of any explicit buffering in the output stack. The stream only knows to compress and write the last bytes when you tell it to close. A flush() probably won't help ... though calling finish() instead of close() should work. Look at the javadocs.)

Here's the correct code (in Java);

package test;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public class GZipTest {

    public static void main(String[] args) throws
                FileNotFoundException, IOException {
        String name = "/tmp/test";
        GZIPOutputStream gz = new GZIPOutputStream(new FileOutputStream(name));
        gz.write(10);
        gz.close();       // Remove this to reproduce the reported bug
        System.out.println(new GZIPInputStream(new FileInputStream(name)).read());
    }
}

(I've not implemented resource management or exception handling / reporting properly as they are not relevant to the purpose of this code. Don't treat this as an example of "good code".)

Regular Expression: Allow letters, numbers, and spaces (with at least one letter or number)

$("#ValuationName").bind("keypress", function (event) {
    if (event.charCode!=0) {
        var regex = new RegExp("^[a-zA-Z ]+$");
        var key = String.fromCharCode(!event.charCode ? event.which : event.charCode);
        if (!regex.test(key)) {
            event.preventDefault();
            return false;
        }
    }
});

How to upgrade PowerShell version from 2.0 to 3.0

The latest PowerShell version as of Sept 2015 is PowerShell 4.0. It's bundled with Windows Management Framework 4.0.

Here's the download page for PowerShelll 4.0 for all versions of Windows. For Windows 7, there are 2 links on that page, 1 for x64 and 1 for x86.

enter image description here

In UML class diagrams, what are Boundary Classes, Control Classes, and Entity Classes?

Often used with/as a part of OOAD and business modeling. The definition by Neil is correct, but it is basically identical to MVC, but just abstracted for the business. The "Good summary" is well done so I will not copy it here as it is not my work, more detailed but inline with Neil's bullet points.

Good summary - Conceito: Entity-Control-Boundary Pattern

OOAD

How can I disable an <option> in a <select> based on its value in JavaScript?

You can also use this function,

function optionDisable(selectId, optionIndices)
{
    for (var idxCount=0; idxCount<optionIndices.length;idxCount++)
    {
        document.getElementById(selectId).children[optionIndices[idxCount]].disabled="disabled";
        document.getElementById(selectId).children[optionIndices[idxCount]].style.backgroundColor = '#ccc';
        document.getElementById(selectId).children[optionIndices[idxCount]].style.color = '#f00';
    }
}

-XX:MaxPermSize with or without -XX:PermSize

-XX:PermSize specifies the initial size that will be allocated during startup of the JVM. If necessary, the JVM will allocate up to -XX:MaxPermSize.

how to fetch array keys with jQuery?

Use an object (key/value pairs, the nearest JavaScript has to an associative array) for this and not the array object. Other than that, I believe that is the most elegant way

var foo = {};
foo['alfa'] = "first item";
foo['beta'] = "second item";

for (var key in foo) {
        console.log(key);
}

Note: JavaScript doesn't guarantee any particular order for the properties. So you cannot expect the property that was defined first to appear first, it might come last.

EDIT:

In response to your comment, I believe that this article best sums up the cases for why arrays in JavaScript should not be used in this fashion -

How do I get a python program to do nothing?

You could use a pass statement:

if condition:
    pass

Python 2.x documentation

Python 3.x documentation

However I doubt you want to do this, unless you just need to put something in as a placeholder until you come back and write the actual code for the if statement.

If you have something like this:

if condition:        # condition in your case being `num2 == num5`
    pass
else:
    do_something()

You can in general change it to this:

if not condition:
    do_something()

But in this specific case you could (and should) do this:

if num2 != num5:        # != is the not-equal-to operator
    do_something()

Git - how delete file from remote repository

Visual Studio Code:

Delete the files from your Explorer view. You see them crossed-out in your Branch view. Then commit and Sync.

enter image description here

Be aware: If files are on your .gitignore list, then the delete "update" will not be pushed and therefore not be visible. VS Code will warn you if this is the case, though. -> Exclude the files/folder from gitignore temporarily.

Phone: numeric keyboard for text input

Using the type="email" or type="url" will give you a keyboard on some phones at least, such as iPhone. For phone numbers, you can use type="tel".

- java.lang.NullPointerException - setText on null object reference

private void fillTextView (int id, String text) {
    TextView tv = (TextView) findViewById(id);
    tv.setText(text);
}

If this is where you're getting the null pointer exception, there was no view found for the id that you passed into findViewById(), and the actual exception is thrown when you try to call a function setText() on null. You should post your XML for R.layout.activity_main, as it's hard to tell where things went wrong just by looking at your code.

More reading on null pointers: What is a NullPointerException, and how do I fix it?

How to set $_GET variable

If you want to fake a $_GET (or a $_POST) when including a file, you can use it like you would use any other var, like that:

$_GET['key'] = 'any get value you want';
include('your_other_file.php');

Nginx: Job for nginx.service failed because the control process exited

change the port may help as 80 port is already using somewhere

vi /etc/nginx/sites-available/default

Change the port:

listen 8080 default_server;
listen [::]:8080 default_server;

And then restart the nginx server

nginx -t
service nginx restart

Set element focus in angular way

The problem with your solution is that it does not work well when tied down to other directives that creates a new scope, e.g. ng-repeat. A better solution would be to simply create a service function that enables you to focus elements imperatively within your controllers or to focus elements declaratively in the html.

DEMO

JAVASCRIPT

Service

 .factory('focus', function($timeout, $window) {
    return function(id) {
      // timeout makes sure that it is invoked after any other event has been triggered.
      // e.g. click events that need to run before the focus or
      // inputs elements that are in a disabled state but are enabled when those events
      // are triggered.
      $timeout(function() {
        var element = $window.document.getElementById(id);
        if(element)
          element.focus();
      });
    };
  });

Directive

  .directive('eventFocus', function(focus) {
    return function(scope, elem, attr) {
      elem.on(attr.eventFocus, function() {
        focus(attr.eventFocusId);
      });

      // Removes bound events in the element itself
      // when the scope is destroyed
      scope.$on('$destroy', function() {
        elem.off(attr.eventFocus);
      });
    };
  });

Controller

.controller('Ctrl', function($scope, focus) {
    $scope.doSomething = function() {
      // do something awesome
      focus('email');
    };
  });

HTML

<input type="email" id="email" class="form-control">
<button event-focus="click" event-focus-id="email">Declarative Focus</button>
<button ng-click="doSomething()">Imperative Focus</button>

VB.NET Connection string (Web.Config, App.Config)

Not clear where My_ConnectionString is coming from in your example, but try this

System.Configuration.ConfigurationManager.ConnectionStrings("My_ConnectionString").ConnectionString

like this

Dim DBConnection As New SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings("My_ConnectionString").ConnectionString)

Create table with jQuery - append

When you use append, jQuery expects it to be well-formed HTML (plain text counts). append is not like doing +=.

You need to make the table first, then append it.

var $table = $('<table/>');
for(var i=0; i<3; i++){
    $table.append( '<tr><td>' + 'result' +  i + '</td></tr>' );
}
$('#here_table').append($table);

Programmatically navigate using React router

React-Router 5.1.0+ Answer (using hooks and React >16.8)

You can use the new useHistory hook on Functional Components and Programmatically navigate:

import { useHistory } from "react-router-dom";

function HomeButton() {
  let history = useHistory();
  // use history.push('/some/path') here
};

React-Router 4.0.0+ Answer

In 4.0 and above, use the history as a prop of your component.

class Example extends React.Component {
   // use `this.props.history.push('/some/path')` here
};

NOTE: this.props.history does not exist in the case your component was not rendered by <Route>. You should use <Route path="..." component={YourComponent}/> to have this.props.history in YourComponent

React-Router 3.0.0+ Answer

In 3.0 and above, use the router as a prop of your component.

class Example extends React.Component {
   // use `this.props.router.push('/some/path')` here
};

React-Router 2.4.0+ Answer

In 2.4 and above, use a higher order component to get the router as a prop of your component.

import { withRouter } from 'react-router';

class Example extends React.Component {
   // use `this.props.router.push('/some/path')` here
};

// Export the decorated class
var DecoratedExample = withRouter(Example);

// PropTypes
Example.propTypes = {
  router: React.PropTypes.shape({
    push: React.PropTypes.func.isRequired
  }).isRequired
};

React-Router 2.0.0+ Answer

This version is backwards compatible with 1.x so there's no need to an Upgrade Guide. Just going through the examples should be good enough.

That said, if you wish to switch to the new pattern, there's a browserHistory module inside the router that you can access with

import { browserHistory } from 'react-router'

Now you have access to your browser history, so you can do things like push, replace, etc... Like:

browserHistory.push('/some/path')

Further reading: Histories and Navigation


React-Router 1.x.x Answer

I will not go into upgrading details. You can read about that in the Upgrade Guide

The main change about the question here is the change from Navigation mixin to History. Now it's using the browser historyAPI to change route so we will use pushState() from now on.

Here's an exemple using Mixin:

var Example = React.createClass({
  mixins: [ History ],
  navigateToHelpPage () {
    this.history.pushState(null, `/help`);
  }
})

Note that this History comes from rackt/history project. Not from React-Router itself.

If you don't want to use Mixin for some reason (maybe because of ES6 class), then you can access the history that you get from the router from this.props.history. It will be only accessible for the components rendered by your Router. So, if you want to use it in any child components it needs to be passed down as an attribute via props.

You can read more about the new release at their 1.0.x documentation

Here is a help page specifically about navigating outside your component

It recommends grabbing a reference history = createHistory() and calling replaceState on that.

React-Router 0.13.x Answer

I got into the same problem and could only find the solution with the Navigation mixin that comes with react-router.

Here's how I did it

import React from 'react';
import {Navigation} from 'react-router';

let Authentication = React.createClass({
  mixins: [Navigation],

  handleClick(e) {
    e.preventDefault();

    this.transitionTo('/');
  },

  render(){
    return (<div onClick={this.handleClick}>Click me!</div>);
  }
});

I was able to call transitionTo() without the need to access .context

Or you could try the fancy ES6 class

import React from 'react';

export default class Authentication extends React.Component {
  constructor(props) {
    super(props);
    this.handleClick = this.handleClick.bind(this);
  }

  handleClick(e) {
    e.preventDefault();

    this.context.router.transitionTo('/');
  }

  render(){
    return (<div onClick={this.handleClick}>Click me!</div>);
  }
}

Authentication.contextTypes = {
  router: React.PropTypes.func.isRequired
};

React-Router-Redux

Note: if you're using Redux, there is another project called React-Router-Redux that gives you redux bindings for ReactRouter, using somewhat the same approach that React-Redux does

React-Router-Redux has a few methods available that allow for simple navigating from inside action creators. These can be particularly useful for people that have existing architecture in React Native, and they wish to utilize the same patterns in React Web with minimal boilerplate overhead.

Explore the following methods:

  • push(location)
  • replace(location)
  • go(number)
  • goBack()
  • goForward()

Here is an example usage, with Redux-Thunk:

./actioncreators.js

import { goBack } from 'react-router-redux'

export const onBackPress = () => (dispatch) => dispatch(goBack())

./viewcomponent.js

<button
  disabled={submitting}
  className="cancel_button"
  onClick={(e) => {
    e.preventDefault()
    this.props.onBackPress()
  }}
>
  CANCEL
</button>

Python: BeautifulSoup - get an attribute value based on the name attribute

theharshest answered the question but here is another way to do the same thing. Also, In your example you have NAME in caps and in your code you have name in lowercase.

s = '<div class="question" id="get attrs" name="python" x="something">Hello World</div>'
soup = BeautifulSoup(s)

attributes_dictionary = soup.find('div').attrs
print attributes_dictionary
# prints: {'id': 'get attrs', 'x': 'something', 'class': ['question'], 'name': 'python'}

print attributes_dictionary['class'][0]
# prints: question

print soup.find('div').get_text()
# prints: Hello World

Is there a way to get LaTeX to place figures in the same page as a reference to that figure?

If you want force this behaviour on all of your figures try

...
\usepackage{float}
\floatplacement{figure}{H}
...

What is difference between sleep() method and yield() method of multi threading?

Sleep() causes the currently executing thread to sleep (temporarily cease execution).

Yield() causes the currently executing thread object to temporarily pause and allow other threads to execute.

enter image description here

Read [this] (Link Removed) for a good explanation of the topic.

How do I center content in a div using CSS?

with all the adjusting css. if possible, wrap it with a table with height and width as 100% and td set it to vertical align to middle, text-align to center

How do I set path while saving a cookie value in JavaScript?

See https://developer.mozilla.org/en/DOM/document.cookie for more documentation:

 setItem: function (sKey, sValue, vEnd, sPath, sDomain, bSecure) {  
     if (!sKey || /^(?:expires|max\-age|path|domain|secure)$/.test(sKey)) { return; }  
     var sExpires = "";  
     if (vEnd) {  
       switch (typeof vEnd) {  
         case "number": sExpires = "; max-age=" + vEnd; break;  
         case "string": sExpires = "; expires=" + vEnd; break;  
         case "object": if (vEnd.hasOwnProperty("toGMTString")) { sExpires = "; expires=" + vEnd.toGMTString(); } break;  
       }  
     }  
     document.cookie = escape(sKey) + "=" + escape(sValue) + sExpires + (sDomain ? "; domain=" + sDomain : "") + (sPath ? "; path=" + sPath : "") + (bSecure ? "; secure" : "");  
   }

Why do we need boxing and unboxing in C#?

In the .NET framework, there are two species of types--value types and reference types. This is relatively common in OO languages.

One of the important features of object oriented languages is the ability to handle instances in a type-agnostic manner. This is referred to as polymorphism. Since we want to take advantage of polymorphism, but we have two different species of types, there has to be some way to bring them together so we can handle one or the other the same way.

Now, back in the olden days (1.0 of Microsoft.NET), there weren't this newfangled generics hullabaloo. You couldn't write a method that had a single argument that could service a value type and a reference type. That's a violation of polymorphism. So boxing was adopted as a means to coerce a value type into an object.

If this wasn't possible, the framework would be littered with methods and classes whose only purpose was to accept the other species of type. Not only that, but since value types don't truly share a common type ancestor, you'd have to have a different method overload for each value type (bit, byte, int16, int32, etc etc etc).

Boxing prevented this from happening. And that's why the British celebrate Boxing Day.

Making a Sass mixin with optional arguments

@mixin box-shadow($left: 0, $top: 0, $blur: 6px, $color: hsla(0,0%,0%,0.25), $inset: false) {
    @if $inset {
        -webkit-box-shadow: inset $left $top $blur $color;
        -moz-box-shadow: inset $left $top $blur $color;
        box-shadow: inset $left $top $blur $color;
    } @else {
        -webkit-box-shadow: $left $top $blur $color;
        -moz-box-shadow: $left $top $blur $color;
        box-shadow: $left $top $blur $color;
    }
}

Get MAC address using shell script

None of the above worked for me because my devices are in a balance-rr bond. Querying either would say the same MAC address with ip l l, ifconfig, or /sys/class/net/${device}/address, so one of them is correct, and one is unknown.

But this works if you haven't renamed the device (any tips on what I missed?):

udevadm info -q all --path "/sys/class/net/${device}"

And this works even if you rename it (eg. ip l set name x0 dev p4p1):

cat /proc/net/bonding/bond0

or my ugly script that makes it more parsable (untested driver/os/whatever compatibility):

awk -F ': ' '
         $0 == "" && interface != "" {
            printf "%s %s %s\n", interface, mac, status;
            interface="";
            mac=""
         }; 
         $1 == "Slave Interface" {
            interface=$2
         }; 
         $1 == "Permanent HW addr" {
            mac=$2
         };
         $1 == "MII Status" {
            status=$2
         };
         END {
            printf "%s %s %s\n", interface, mac, status
         }' /proc/net/bonding/bond0

How do I drop a MongoDB database from the command line?

Open another terminal window and execute the following commands,

mongodb
use mydb
db.dropDatabase()

Output of that operation shall look like the following

MAC:FOLDER USER$ mongodb
> show databases
local      0.78125GB
mydb       0.23012GB
test       0.23012GB
> use mydb
switched to db mydb
>db.dropDatabase()
{ "dropped" : "mydb", "ok" : 1 }
>

Please note that mydb is still in use, hence inserting any input at that time will initialize the database again.

How to use continue in jQuery each() loop?

return or return false are not the same as continue. If the loop is inside a function the remainder of the function will not execute as you would expect with a true "continue".

Remove title in Toolbar in appcompat-v7

If you are using Toolbar try below code:

toolbar.setTitle("");

How do I replace multiple spaces with a single space in C#?

You can simply do this in one line solution!

string s = "welcome to  london";
s.Replace(" ", "()").Replace(")(", "").Replace("()", " ");

You can choose other brackets (or even other characters) if you like.

add item in array list of android

item=sp.getItemAtPosition(i).toString();
list.add(item);
adapter.notifyDataSetChanged () ;

look up ArrayAdapter.notifyDataSetChanged()

iReport not starting using JRE 8

I fixed this on my PC, on my environment iReport was iReport-5.1.0 , both jdk 7 and jdk 8 had been installed.

but iReport did not load

fix:- 1. Find the iReport.conf //C:\Program Files (x86)\Jaspersoft\iReport-5.1.0\etc

  1. Open it on text editor

  2. copy your jdk installation path //C:\Program Files (x86)\Java\jdk1.8.0_60

  3. add jdkhome= into the ireport.conf file jdkhome="C:/Program Files (x86)/Java/jdk1.8.0_60"

enter image description here

Now iReport will work

Still getting warning : Configuration 'compile' is obsolete and has been replaced with 'implementation'

Just updating google-service version did not work for me.

  • First make sure all your dependencies compile are replaced with implementation.
  • Update all dependencies in your project. Because if one of your dependency is having compile then your project will show this error. So update all dependencies version.

How to show text in combobox when no item selected?

I used a quick work around so I could keep the DropDownList style.

class DummyComboBoxItem
{
    public string DisplayName
    {
        get
        {
            return "Make a selection ...";
        }
    }
}
public partial class mainForm : Form
{
    private DummyComboBoxItem placeholder = new DummyComboBoxItem();
    public mainForm()
    {
        InitializeComponent();

        myComboBox.DisplayMember = "DisplayName";            
        myComboBox.Items.Add(placeholder);
        foreach(object o in Objects)
        {
            myComboBox.Items.Add(o);
        }
        myComboBox.SelectedItem = placeholder;
    }

    private void myComboBox_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (myComboBox.SelectedItem == null) return;
        if (myComboBox.SelectedItem == placeholder) return;            
        /*
            do your stuff
        */
        myComboBox.Items.Add(placeholder);
        myComboBox.SelectedItem = placeholder;
    }

    private void myComboBox_DropDown(object sender, EventArgs e)
    {
        myComboBox.Items.Remove(placeholder);
    }

    private void myComboBox_Leave(object sender, EventArgs e)
    {
        //this covers user aborting the selection (by clicking away or choosing the system null drop down option)
        //The control may not immedietly change, but if the user clicks anywhere else it will reset
        if(myComboBox.SelectedItem != placeholder)
        {
            if(!myComboBox.Items.Contains(placeholder)) myComboBox.Items.Add(placeholder);
            myComboBox.SelectedItem = placeholder;
        }            
    }       
}

If you use databinding you'll have to create a dummy version of the type you're bound to - just make sure you remove it before any persistence logic.

How to see full absolute path of a symlink

unix flavors -> ll symLinkName

OSX -> readlink symLinkName

Difference is 1st way would display the sym link path in a blinking way and 2nd way would just echo it out on the console.

javascript get child by id

document.getElementById('child') should return you the correct element - remember that id's need to be unique across a document to make it valid anyway.

edit : see this page - ids MUST be unique.

edit edit : alternate way to solve the problem :

<div onclick="test('child1')">
    Test
    <div id="child1">child</div>
</div>

then you just need the test() function to look up the element by id that you passed in.

How do I find out my root MySQL password?

For RHEL-mysql 5.5:

/etc/init.d/mysql stop

/etc/init.d/mysql start --skip-grant-tables

 mysql> UPDATE mysql.user SET Password=PASSWORD('newpwd') WHERE User='root';
 mysql> FLUSH PRIVILEGES;
 mysql> exit;

mysql -uroot -pnewpwd

mysql>  

Can't compare naive and aware datetime.now() <= challenge.datetime_end

It is working form me. Here I am geeting the table created datetime and adding 10 minutes on the datetime. later depending on the current time, Expiry Operations are done.

from datetime import datetime, time, timedelta
import pytz

Added 10 minutes on database datetime

table_datetime = '2019-06-13 07:49:02.832969' (example)

# Added 10 minutes on database datetime
# table_datetime = '2019-06-13 07:49:02.832969' (example)

table_expire_datetime = table_datetime + timedelta(minutes=10 )

# Current datetime
current_datetime = datetime.now()


# replace the timezone in both time
expired_on = table_expire_datetime.replace(tzinfo=utc)
checked_on = current_datetime.replace(tzinfo=utc)


if expired_on < checked_on:
    print("Time Crossed)
else:
    print("Time not crossed ")

It worked for me.

How do I escape double and single quotes in sed?

Escaping a double quote can absolutely be necessary in sed: for instance, if you are using double quotes in the entire sed expression (as you need to do when you want to use a shell variable).

Here's an example that touches on escaping in sed but also captures some other quoting issues in bash:

# cat inventory
PURCHASED="2014-09-01"
SITE="Atlanta"
LOCATION="Room 154"

Let's say you wanted to change the room using a sed script that you can use over and over, so you variablize the input as follows:

# i="Room 101" (these quotes are there so the variable can contains spaces)

This script will add the whole line if it isn't there, or it will simply replace (using sed) the line that is there with the text plus the value of $i.

if grep -q LOCATION inventory; then 
## The sed expression is double quoted to allow for variable expansion; 
## the literal quotes are both escaped with \ 
    sed -i "/^LOCATION/c\LOCATION=\"$i\"" inventory
## Note the three layers of quotes to get echo to expand the variable
## AND insert the literal quotes
else 
    echo LOCATION='"'$i'"' >> inventory
fi

P.S. I wrote out the script above on multiple lines to make the comments parsable but I use it as a one-liner on the command line that looks like this:

i="your location"; if grep -q LOCATION inventory; then sed -i "/^LOCATION/c\LOCATION=\"$i\"" inventory; else echo LOCATION='"'$i'"' >> inventory; fi

WCF vs ASP.NET Web API

The new ASP.NET Web API is a continuation of the previous WCF Web API project (although some of the concepts have changed).

WCF was originally created to enable SOAP-based services. For simpler RESTful or RPCish services (think clients like jQuery) ASP.NET Web API should be good choice.


For us, WCF is used for SOAP and Web API for REST. I wish Web API supported SOAP too. We are not using advanced features of WCF. Here is comparison from MSDN:

enter image description here


ASP.net Web API is all about HTTP and REST based GET,POST,PUT,DELETE with well know ASP.net MVC style of programming and JSON returnable; web API is for all the light weight process and pure HTTP based components. For one to go ahead with WCF even for simple or simplest single web service it will bring all the extra baggage. For light weight simple service for ajax or dynamic calls always WebApi just solves the need. This neatly complements or helps in parallel to the ASP.net MVC.

Check out the podcast : Hanselminutes Podcast 264 - This is not your father's WCF - All about the WebAPI with Glenn Block by Scott Hanselman for more information.


In the scenarios listed below you should go for WCF:

  1. If you need to send data on protocols like TCP, MSMQ or MIME
  2. If the consuming client just knows how to consume SOAP messages

WEB API is a framework for developing RESTful/HTTP services.

There are so many clients that do not understand SOAP like Browsers, HTML5, in those cases WEB APIs are a good choice.

HTTP services header specifies how to secure service, how to cache the information, type of the message body and HTTP body can specify any type of content like HTML not just XML as SOAP services.

Build unsigned APK file with Android Studio

Following work for me:

Keep following setting blank if you have made in build.gradle.

signingConfigs {
        release {
            storePassword ""
            keyAlias ""
            keyPassword ""
        }
    }

and choose Gradle Task from your Editor window. It will show list of all flavor if you have created.

enter image description here

Python way to clone a git repository

Here's a way to print progress while cloning a repo with GitPython

import time
import git
from git import RemoteProgress

class CloneProgress(RemoteProgress):
    def update(self, op_code, cur_count, max_count=None, message=''):
        if message:
            print(message)

print('Cloning into %s' % git_root)
git.Repo.clone_from('https://github.com/your-repo', '/your/repo/dir', 
        branch='master', progress=CloneProgress())

Get the Last Inserted Id Using Laravel Eloquent

For Laravel, If you insert a new record and call $data->save() this function executes an INSERT query and returns the primary key value (i.e. id by default).

You can use following code:

if($data->save()) {
    return Response::json(array('status' => 1, 'primary_id'=>$data->id), 200);
}