Programs & Examples On #Httpruntime

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

I got the same problem with dotnet core and managed to fix it by clearing the NuGet cache.

Open the powershell and enter the following command.

dotnet nuget locals all --clear

Then I closed Visual Studio, opened it again and entered the following command into the Package Manager Console:


NuGet should now restore all packages and popultes the nuget cache again.

After that I was able to build and start my dotnet core webapi in a Linux container.

"The underlying connection was closed: An unexpected error occurred on a send." With SSL Certificate

The code below resolved the issue

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls Or SecurityProtocolType.Ssl3

Could not load file or assembly System.Web.Http.WebHost after published to Azure web site

I met the same problem and I resolved it by setting CopyLocal to true for the following libs:


I must add that I use MVC4 and NET 4

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

same thing JUST happened to me with NUGET.

the following tag helped

<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
    <assemblyIdentity name="System.Web.WebPages.Razor" PublicKeyToken="31bf3856ad364e35"/>
    <bindingRedirect oldVersion="" newVersion=""/>

Also if this is happening on the server, I had to make sure I was running the application pool on a more "privileged account" to the file system, but I don think that's your issue here

Could not load file or assembly 'System.Web.Http 4.0.0 after update from 2012 to 2013

Change the Specfic version flag from true to false for the dll in the reference

Exception of type 'System.OutOfMemoryException' was thrown.

If you're using IIS Express, select Show All Application from IIS Express in the task bar notification area, then select Stop All.

Now re-run your application.

Specified argument was out of the range of valid values. Parameter name: site

This resolved the issue on Windows 10 after the last update

go Control Panel ->> Programs ->> Programs and Features ->> Turn Windows features on or off ->> Internet Information Services

But based on previous response it doesn't work unless checking all these options as on pic below

enter image description here

WCF Service, the type provided as the service attribute values…could not be found

This is an old bug, but I encountered it today on a web service which had barely been altered since being created via "New \ Project.."

For me, this issue was caused by the "IService.cs" file containing the following:

<%@ ServiceHost Language="C#" Debug="true" Service="JSONWebService.Service1.svc" CodeBehind="Service1.svc.cs" %>

Notice the value in the Service attribute contains ".svc" at the end.

This shouldn't be there.

Removing those 4 characters resolved this issue.

<%@ ServiceHost Language="C#" Debug="true" Service="JSONWebService.Service1" CodeBehind="Service1.svc.cs" %>

Note that you need to open this file from outside of Visual Studio.

Visual Studio shows one file, Service1.cs in the Solution Explorer, but that only lets you alter Service1.svc.cs, not the Service1.svc file.

The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception

I had the duplicit definition of connection string in my WCF service. I was able to debug the service and to see the inner error message (not displayed by default):

ConfigurationErrorsException: The entry 'xxxEntities' has 
already been added. (C:\Users\WcfService\web.config line 35). 

which was after web.config transformation (note duplicit values)

    <add name="xxxEntities" connectionString="metadata=res://*/ ...
    <add name="xxxEntities" connectionString="metadata=res://*/ ...

Hence removing unwanted connection string solved my problem.

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

I don't know if this still is an issue, but i prefere just to use the My.Settings in my code.

Visual Studio generates a simple class with functions for reading settings from the app.config file.

You can simply access it using My.Settings.ConnectionString.

    Using Context As New Data.Context.DataClasses()
        Context.Connection.ConnectionString = My.Settings.ConnectionString
    End Using

how to increase MaxReceivedMessageSize when calling a WCF from C#

Change the customBinding in the web.config to use larger defaults. I picked 2MB as it is a reasonable size. Of course setting it to 2GB (as your code suggests) will work but it does leave you more vulnerable to attacks. Pick a size that is larger than your largest request but isn't overly large.

Check this : Using Large Message Requests in Silverlight with WCF

       <behavior name="TestLargeWCF.Web.MyServiceBehavior">
         <serviceMetadata httpGetEnabled="true"/>
         <serviceDebug includeExceptionDetailInFaults="false"/>
       <binding name="customBinding0">
         <binaryMessageEncoding />
         <!-- Start change -->
         <httpTransport maxReceivedMessageSize="2097152"
         <!-- Stop change -->
   <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
     <service behaviorConfiguration="Web.MyServiceBehavior" name="TestLargeWCF.Web.MyService">
       <endpoint address=""
       <endpoint address="mex"

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

In my case I had an issue around using Microsoft.ReportViewer.WebForms. I removed validate=true from add verb line in web.config and it started working:

      <add verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />

how to set width for PdfPCell in ItextSharp

Try something like this

PdfPCell cell;
PdfPTable tableHeader;
PdfPTable tmpTable;
PdfPTable table = new PdfPTable(10) { WidthPercentage = 100, RunDirection = PdfWriter.RUN_DIRECTION_LTR, ExtendLastRow = false };

// row 1 / cell 1 (merge)
PdfPCell _c = new PdfPCell(new Phrase("SER. No")) { Rotation = -90, VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER, BorderWidth = 1 };
_c.Rowspan = 2;


// row 1 / cell 2
_c = new PdfPCell(new Phrase("TYPE OF SHIPPING")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };

// row 1 / cell 3
_c = new PdfPCell(new Phrase("ORDER NO.")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };

// row 1 / cell 4
_c = new PdfPCell(new Phrase("QTY.")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };

// row 1 / cell 5
_c = new PdfPCell(new Phrase("DISCHARGE PPORT")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };

// row 1 / cell 6 (merge)
_c = new PdfPCell(new Phrase("DESCRIPTION OF GOODS")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };
_c.Rowspan = 2;

// row 1 / cell 7
_c = new PdfPCell(new Phrase("LINE DOC. RECI. DATE")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };

// row 1 / cell 8 (merge)
_c = new PdfPCell(new Phrase("OWNER DOC. RECI. DATE")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };
_c.Rowspan = 2;

// row 1 / cell 9 (merge)
_c = new PdfPCell(new Phrase("CLEARANCE DATE")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };
_c.Rowspan = 2;

// row 1 / cell 10 (merge)
_c = new PdfPCell(new Phrase("CUSTOM PERMIT NO.")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };
_c.Rowspan = 2;

// row 2 / cell 2
_c = new PdfPCell(new Phrase("AWB / BL NO.")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };

// row 2 / cell 3
_c = new PdfPCell(new Phrase("COMPLEX NAME")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };

// row 2 / cell 4
_c = new PdfPCell(new Phrase("G.W Kgs.")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };

// row 2 / cell 5
_c = new PdfPCell(new Phrase("DESTINATON")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };

// row 2 / cell 7
_c = new PdfPCell(new Phrase("OWNER DOC. RECI. DATE")) { VerticalAlignment = Element.ALIGN_MIDDLE, HorizontalAlignment = Element.ALIGN_CENTER };


You might need to re-adjust slightly on the widths and borders but that is a one shot to do.

Handler "ExtensionlessUrlHandler-Integrated-4.0" has a bad module "ManagedPipelineHandler" in its module list

The problem

You are using SimpleWorkerRequest in a scenario that it wasn't designed for. You are using it inside of IIS. If you look at the prior MSDN link (emphasis is mine):

Provides a simple implementation of the HttpWorkerRequest abstract class that can be used to host ASP.NET applications outside an Internet Information Services (IIS) application. You can employ SimpleWorkerRequest directly or extend it.

Also, if you look at the MSDN documentation for the System.Web.Hosting namespace (SimpleWorkerRequest is in this namespace), you will also see something similar to the above (again, emphasis is mine):

The System.Web.Hosting namespace provides the functionality for hosting ASP.NET applications from managed applications outside Microsoft Internet Information Services (IIS).

The solution

I would recommend removing the call to SimpleWorkerRequest. Instead, you can use a Microsoft solution to make sure your web site automatically starts up after it recycles. What you need is the Microsoft Application Initialization Module for IIS 7.5. It is not complicated to configure, but you need to understand the exact options. This is why I would also recommend the Application Initialization UI for IIS 7.5. The UI is written by an MSDN blogger.

So what exactly does the Microsoft solution do? It does what you are trying to do - IIS sends a "get" request to your website after the application pool is started.

403 - Forbidden: Access is denied. You do not have permission to view this directory or page using the credentials that you supplied

In my case, the issue was new sites had an implicit deny of all IP addresses unless an explicit allow was created. To fix: Under the site in Features View: Under the IIS Section > IP Address and Domain Restrictions > Edit Feature Settings > Set 'Access for unspecified clients:' to 'Allow'

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

I had the same problem. I tried installing Visual Studio 2010 SP1 but it didn't worked.

Finally I get Microsoft.Web.Infrastructure.dll from the colleague. You can find the dll into your friends PC where the project is perfectly working. Try to search dll into Temp/Temporary ASP.NET Files. Go to Temp using %temp% into run window.

After getting dll into your pc, just add reference to your project and it will work.

The module was expected to contain an assembly manifest

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

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

Hope this helps.

The type or namespace name does not exist in the namespace 'System.Web.Mvc'

I had the same issue, but none of the above worked for me. They did put me in to the right direction though.

For example when I set the "Copy Local" to "true" for System.Web.Mvc reference, it automatically sets it back to False.

I have multiple projects which depend on the System.Web.Mvc reference in my solution, but only one caused this problem. In VS 2012 this reference is labeled with the yellow attention triangle.

Find this reference => remove it => re-add it

That fixed it for me. Hope this helps

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

I first tried Mohammed Emad's answer - no joy. Then I tried

git clean -x -d -f

which brought me to a new "Roslyn" error which I was able to fix by manually editing my .csproj.

Interestingly, after I'd read down a bit further down the page on the Roslyn question, I found another suggestion with even more votes (Update-Package Microsoft.CodeDom.Providers.DotNetCompilerPlatform -r). Thinking I'd rather implement that than manually edit .csproj, I backed out my .csproj changes, only to find my solution was still working.

So after all that, I'm wondering if Mohammed's answer (on this page) would have done the trick, had I simply done the git clean first.

Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. The statement has been terminated

Timeout expired because the sql query is taking more time than you set in sqlCommand.CommandTimeout property.

Obviously you can increase CommandTimeout to solve this issue but before doing that you must optimize your query by adding index. If you run your query in Sql server management studio including actual execution plan then Sql server management studio will suggest you proper index. Most of the case you will get rid of timeout issue if you can optimize your query.

What is limiting the # of simultaneous connections my ASP.NET application can make to a web service?

See the "Threading" section of this page:, in conjunction with the "Connections" section.

Have you tried upping the maxconnection attribute of your processModel setting?

How to solve error message: "Failed to map the path '/'."

Changing pool from ASP.NET v4.0 to Framework4 worked for me.

Getting "A potentially dangerous Request.Path value was detected from the client (&)"

We were getting this same error in Fiddler when trying to figure out why our Silverlight ArcGIS map viewer wasn't loading the map. In our case it was a typo in the URL in the code. There was an equal sign in there for some reason.
instead of

After taking out that equal sign it worked great (of course).

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

This is an old post, but it may help some people searching on this error to try setting "Enable 32-Bit Applications" to True for the app pool. That is what resolved the error for me. I came upon this solution by reading some the comments to @beckelmw's answer.

Setting Timeout Value For .NET Web Service

After creating your client specifying the binding and endpoint address, you can assign an OperationTimeout,

client.InnerChannel.OperationTimeout = new TimeSpan(0, 5, 0);

Catching "Maximum request length exceeded"

In IIS 7 and beyond:

web.config file:

  <security >
      <requestLimits maxAllowedContentLength="[Size In Bytes]" />

You can then check in code behind, like so:

If FileUpload1.PostedFile.ContentLength > 2097152 Then ' (2097152 = 2 Mb)
  ' Exceeded the 2 Mb limit
  ' Do something
End If

Just make sure the [Size In Bytes] in the web.config is greater than the size of the file you wish to upload then you won't get the 404 error. You can then check the file size in code behind using the ContentLength which would be much better

How do I set the request timeout for one controller action in an mvc application

<location path="ControllerName/ActionName">
        <httpRuntime executionTimeout="1000"/>

Probably it is better to set such values in web.config instead of controller. Hardcoding of configurable options is considered harmful.

How to increase the max upload file size in ASP.NET?

I have a blog post on how to increase the file size for asp upload control.

From the post:

By default, the FileUpload control allows a maximum of 4MB file to be uploaded and the execution timeout is 110 seconds. These properties can be changed from within the web.config file’s httpRuntime section. The maxRequestLength property determines the maximum file size that can be uploaded. The executionTimeout property determines the maximum time for execution.

SQL update from one Table to another based on a ID match

update within the same table:

        No Int
        ,Name NVarchar(50)
        ,linkNo int

        No Int
        ,Name NVarchar(50)
        ,linkNo int

    INSERT INTO @TB1 VALUES(1,'changed person data',  0);
    INSERT INTO @TB1 VALUES(2,'old linked data of person', 1);



    UPDATE @TB1 
        SET Name = T2.Name
    FROM        @TB1 T1
    INNER JOIN  @TB2 T2 ON T2.No = T1.linkNo


How to squash commits in git after they have been pushed?

Squash commits locally with

git rebase -i origin/master~4 master

and then force push with

git push origin +master

Difference between --force and +

From the documentation of git push:

Note that --force applies to all the refs that are pushed, hence using it with push.default set to matching or with multiple push destinations configured with remote.*.push may overwrite refs other than the current branch (including local refs that are strictly behind their remote counterpart). To force a push to only one branch, use a + in front of the refspec to push (e.g git push origin +master to force a push to the master branch).

How to compare two tags with git?

As @Nakilon said, their is a comparing tool built in github if that's what you use.

To use it, append the url of the repo with "/compare".

How to parse a JSON and turn its values into an Array?

for your example:

{'profiles': [{'name':'john', 'age': 44}, {'name':'Alex','age':11}]}

you will have to do something of this effect:

JSONObject myjson = new JSONObject(the_json);
JSONArray the_json_array = myjson.getJSONArray("profiles");

this returns the array object.

Then iterating will be as follows:

    int size = the_json_array.length();
    ArrayList<JSONObject> arrays = new ArrayList<JSONObject>();
    for (int i = 0; i < size; i++) {
        JSONObject another_json_object = the_json_array.getJSONObject(i);
            //Blah blah blah...

JSONObject[] jsons = new JSONObject[arrays.size()];

//The end...

You will have to determine if the data is an array (simply checking that charAt(0) starts with [ character).

Hope this helps.

Difference between session affinity and sticky session?

This article clarifies the question for me and discusses other types of load balancer persistence.

Dave's Thoughts: Load balancer persistence (sticky sessions)

How can I create an Asynchronous function in Javascript?

Function.prototype.applyAsync = function(params, cb){
      var function_context = this;
          var val = function_context.apply(undefined, params); 
          if(cb) cb(val);
      }, 0);

// usage
var double = function(n){return 2*n;};
var display = function(){console.log(arguments); return undefined;};
double.applyAsync([3], display);

Although not fundamentally different than the other solutions, I think my solution does a few additional nice things:

  • it allows for parameters to the functions
  • it passes the output of the function to the callback
  • it is added to Function.prototype allowing a nicer way to call it

Also, the similarity to the built-in function Function.prototype.apply seems appropriate to me.

Updating the list view when the adapter data changes




((BaseAdapter) mMyListView.getAdapter()).notifyDataSetChanged(); 

If that doesnt work, refer to this thread: Android List view refresh

How to parse XML using jQuery?

$xml = $( $.parseXML( xml ) );

    // elem = found XML element

Can't push image to Amazon ECR - fails with "no basic auth credentials"

The docker command given by aws-cli is little off...

When using docker login, docker will save a server:key pair either in your keychain or ~/.docker/config.json file

If it saves the key under the lookup for the key during push will fail because docker will be looking for a server named not

Use the following command to login:

eval $(aws ecr get-login --no-include-email --region us-east-1 --profile yourprofile | sed 's|https://||')

Once you run the command you will get 'Login Succeeded' message and then you are good
after that your push command should work

What is ":-!!" in C code?

This is, in effect, a way to check whether the expression e can be evaluated to be 0, and if not, to fail the build.

The macro is somewhat misnamed; it should be something more like BUILD_BUG_OR_ZERO, rather than ...ON_ZERO. (There have been occasional discussions about whether this is a confusing name.)

You should read the expression like this:

sizeof(struct { int: -!!(e); }))
  1. (e): Compute expression e.

  2. !!(e): Logically negate twice: 0 if e == 0; otherwise 1.

  3. -!!(e): Numerically negate the expression from step 2: 0 if it was 0; otherwise -1.

  4. struct{int: -!!(0);} --> struct{int: 0;}: If it was zero, then we declare a struct with an anonymous integer bitfield that has width zero. Everything is fine and we proceed as normal.

  5. struct{int: -!!(1);} --> struct{int: -1;}: On the other hand, if it isn't zero, then it will be some negative number. Declaring any bitfield with negative width is a compilation error.

So we'll either wind up with a bitfield that has width 0 in a struct, which is fine, or a bitfield with negative width, which is a compilation error. Then we take sizeof that field, so we get a size_t with the appropriate width (which will be zero in the case where e is zero).

Some people have asked: Why not just use an assert?

keithmo's answer here has a good response:

These macros implement a compile-time test, while assert() is a run-time test.

Exactly right. You don't want to detect problems in your kernel at runtime that could have been caught earlier! It's a critical piece of the operating system. To whatever extent problems can be detected at compile time, so much the better.

java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonFactory

I have had the same error. I added dependency on pom.xml (I am working with Maven)


I started trying with version 2.9.0, then I found a different error (com/fasterxml/jackson/core/exc/InputCoercionException) then I try different versions until all errors were solved with version 2.12.1

JS: Uncaught TypeError: object is not a function (onclick)

I was able to figure it out by following the answer in this thread:

Basically, I renamed all values, function names, and element names to different values so they wouldn't conflict - and it worked!

Adding local .aar files to Gradle build using "flatDirs" is not working

Update : As @amram99 mentioned, the issue has been fixed as of the release of Android Studio v1.3.

Tested and verified with below specifications

  • Android Studio v1.3
  • gradle plugin v1.2.3
  • Gradle v2.4

What works now

  • Now you can import a local aar file via the File>New>New Module>Import .JAR/.AAR Package option in Android Studio v1.3

  • However the below answer holds true and effective irrespective of the Android Studio changes as this is based of gradle scripting.

Old Answer : In a recent update the people at android broke the inclusion of local aar files via the Android Studio's add new module menu option. Check the Issue listed here. Irrespective of anything that goes in and out of IDE's feature list , the below method works when it comes to working with local aar files.(Tested it today):

Put the aar file in the libs directory (create it if needed), then, add the following code in your build.gradle :

dependencies {
   compile(name:'nameOfYourAARFileWithoutExtension', ext:'aar')
              dirs 'libs'

When to use malloc for char pointers

Use malloc() when you don't know the amount of memory needed during compile time. In case if you have read-only strings then you can use const char* str = "something"; . Note that the string is most probably be stored in a read-only memory location and you'll not be able to modify it. On the other hand if you know the string during compiler time then you can do something like: char str[10]; strcpy(str, "Something"); Here the memory is allocated from stack and you will be able to modify the str. Third case is allocating using malloc. Lets say you don'r know the length of the string during compile time. Then you can do char* str = malloc(requiredMem); strcpy(str, "Something"); free(str);

Single quotes vs. double quotes in Python

In Perl you want to use single quotes when you have a string which doesn't need to interpolate variables or escaped characters like \n, \t, \r, etc.

PHP makes the same distinction as Perl: content in single quotes will not be interpreted (not even \n will be converted), as opposed to double quotes which can contain variables to have their value printed out.

Python does not, I'm afraid. Technically seen, there is no $ token (or the like) to separate a name/text from a variable in Python. Both features make Python more readable, less confusing, after all. Single and double quotes can be used interchangeably in Python.

Laravel where on relationship object


A bit OOT, but this question is the most closest topic with my question.

Here is an example if you want to show Event where ALL participant meet certain requirement. Let's say, event where ALL the participant has fully paid. So, it WILL NOT return events which having one or more participants that haven't fully paid .

Simply use the whereDoesntHave of the others 2 statuses.

Let's say the statuses are haven't paid at all [eq:1], paid some of it [eq:2], and fully paid [eq:3]

Event::whereDoesntHave('participants', function ($query) {
   return $query->whereRaw('payment = 1 or payment = 2');

Tested on Laravel 5.8 - 7.x

Nested JSON objects - do I have to use arrays for everything?

You have too many redundant nested arrays inside your jSON data, but it is possible to retrieve the information. Though like others have said you might want to clean it up.

use each() wrap within another each() until the last array.

for[0].stuff[0].onetype[0] in jQuery you could do the following:


$.each(, function(index0, v) {
    $.each(v, function (index1, w) {
        $.each(w, function (index2, x) {



Can't connect to local MySQL server through socket '/tmp/mysql.sock

Check that your mysql has not reached maximum connections, or is not in some sort of booting loop as happens quite often if the settings are incorrect in my.cnf.

Use ps aux | grep mysql to check if the PID is changing.

How do I compare strings in GoLang?

For the Platform Independent Users or Windows users, what you can do is:

import runtime:

import (

and then trim the string like this:

if runtime.GOOS == "windows" {
  input = strings.TrimRight(input, "\r\n")
} else {
  input = strings.TrimRight(input, "\n")

now you can compare it like that:

if strings.Compare(input, "a") == 0 {

This is a better approach when you're making use of STDIN on multiple platforms.


This happens because on windows lines end with "\r\n" which is known as CRLF, but on UNIX lines end with "\n" which is known as LF and that's why we trim "\n" on unix based operating systems while we trim "\r\n" on windows.

Disable scrolling when touch moving certain element

The ultimate solution would be setting overflow: hidden; on document.documentElement like so:

/* element is an HTML element You want catch the touch */
element.addEventListener('touchstart', function(e) { = 'hidden';

document.addEventListener('touchend', function(e) { = 'auto';

By setting overflow: hidden on start of touch it makes everything exceeding window hidden thus removing availability to scroll anything (no content to scroll).

After touchend the lock can be freed by setting overflow to auto (the default value).

It is better to append this to <html> because <body> may be used to do some styling, plus it can make children behave unexpectedly.

EDIT: About touch-action: none; - Safari doesn't support it according to MDN.

Should I use 'border: none' or 'border: 0'?

They are equivalent in effect, pointing to different shortcuts:

border: 0;
//short for..
border-width: 0;

And the other..

border: none;
//short for...
border-style: none;

Both work, just pick one and go with it :)

error: Libtool library used but 'LIBTOOL' is undefined

In my case on macOS I solved it with:

brew link libtool

SVN (Subversion) Problem "File is scheduled for addition, but is missing" - Using Versions

Avoid using Xcode to rename files in a folder reference. If you rename a file using Xcode, it will be marked for commit. If you later delete it before the commit, you will end up with this error.

Increment a value in Postgres

UPDATE totals 
   SET total = total + 1
WHERE name = 'bill';

If you want to make sure the current value is indeed 203 (and not accidently increase it again) you can also add another condition:

UPDATE totals 
   SET total = total + 1
WHERE name = 'bill'
  AND total = 203;

Easiest way to loop through a filtered list with VBA?

Suppose I have numbers 1 to 10 in cells A2:A11 with my autofilter in A1. I now filter to only show numbers greater then 5 (i.e. 6, 7, 8, 9, 10).

This code will only print visible cells:

Sub SpecialLoop()
    Dim cl As Range, rng As Range

    Set rng = Range("A2:A11")

    For Each cl In rng
        If cl.EntireRow.Hidden = False Then //Use Hidden property to check if filtered or not
            Debug.Print cl
        End If

End Sub

Perhaps there is a better way with SpecialCells but the above worked for me in Excel 2003.


Just found a better way with SpecialCells:

Sub SpecialLoop()
    Dim cl As Range, rng As Range

    Set rng = Range("A2:A11")

    For Each cl In rng.SpecialCells(xlCellTypeVisible)
        Debug.Print cl
    Next cl

End Sub

How to fix docker: Got permission denied issue

After you installed docker, created 'docker' group and added user to it, edit docker service unit file:

sudo nano /usr/lib/systemd/system/docker.service

Add two lines into the section [Service]:

ExecStartPost=/bin/chmod 666 /var/run/docker.sock

Save the file (Ctrl-X, y, Enter)

Run and enable the Docker service:

sudo systemctl daemon-reload
sudo systemctl start docker
sudo systemctl enable docker

How to trigger HTML button when you press Enter in textbox?

It is, yeah, 2021. And I believe this still holds true.

DO NOT USE keypress

  1. keypress event is not triggered when the user presses a key that does not produce any character, such as Tab, Caps Lock, Delete, Backspace, Escape, left & right Shift, function keys(F1 - F12).

keypress event Mozilla Developer Network

The keypress event is fired when a key is pressed down, and that key normally produces a character value. Use input instead.

  1. It has been deprecated.

keypress event UI Events (W3C working draft published on November 8, 2018.)

  • NOTE | The keypress event is traditionally associated with detecting a character value rather than a physical key, and might not be available on all keys in some configurations.
  • WARNING | The keypress event type is defined in this specification for reference and completeness, but this specification deprecates the use of this event type. When in editing contexts, authors can subscribe to the beforeinput event instead.

DO NOT USE KeyboardEvent.keyCode

  1. It has been deprecated.

KeyboardEvent.keyCode Mozilla Developer Network

Deprecated | This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

What should I use then? (The good practice)

// Make sure this code gets executed after the DOM is loaded.
document.querySelector("#addLinks").addEventListener("keyup", event => {
    if(event.key !== "Enter") return; // Use `.key` instead.
    document.querySelector("#linkadd").click(); // Things you want to do.
    event.preventDefault(); // No need to `return false;`.

Escaping single quote in PHP when inserting into MySQL

You can do the following which escapes both PHP and MySQL.

$text = '<a href="\\\'\\\');"></a>';

This will reflect MySQL as

<a href="'');"></a>

How does it work?

We know that both PHP and MySQL apostrophes can be escaped with backslash and then apostrophe.


Because we are using PHP to insert into MySQL, we need PHP to still write the backslash to MySQL so it too can escape it. So we use the PHP escape character of backslash-backslash together with backslash-apostrophe to achieve this.


"Invalid signature file" when attempting to run a .jar

Please use the following command

zip -d yourjar.jar 'META-INF/*.SF' 'META-INF/*.RSA' 'META-INF/*SF'

Delete forked repo from GitHub

No, it will not affect your original repository, just make sure that the repo address looks like "youGitName/TheRepository" and not like "OtherPersonGitName/TheRepo".

Difference between "char" and "String" in Java

I would recommend you to read through the Java tutorial documentation hosted on Oracle's website whenever you are in doubt about anything related to Java.

You can get a clear understanding of the concepts by going through the following tutorials:

Twitter Bootstrap Tabs: Go to Specific Tab on Page Reload or Hyperlink

I make sth like this for links with ajax #!# (e.g./!#test3) but you can modify it whatever you like

$(document).ready(function() {

       let hash = document.location.hash;
       let prefix = "!#";

       //change hash url on page reload
       if (hash) {
         $('.nav-tabs a[href=\"'+hash.replace(prefix,"")+'\"]').tab('show');

       // change hash url on switch tab
       $('.nav-tabs a').on('', function (e) {
          window.location.hash ="#", "#" + prefix);

Example with simple page on Github here

Find duplicate entries in a column

Try this query.. It uses the Analytic function SUM:

 FROM table1 a 
 WHERE s_ind ='Y'   
WHERE cnt > 2

Am not sure why you are identifying a record as a duplicate if the ctn_no repeats more than 2 times. FOr me it repeats more than once it is a duplicate. In this case change the las part of the query to WHERE cnt > 1

How to read a .xlsx file using the pandas Library in iPython?

DataFrame's read_excel method is like read_csv method:

dfs = pd.read_excel(xlsx_file, sheetname="sheet1")

Help on function read_excel in module

read_excel(io, sheetname=0, header=0, skiprows=None, skip_footer=0, index_col=None, names=None, parse_cols=None, parse_dates=False, date_parser=None, na_values=None, thousands=None, convert_float=True, has_index_names=None, converters=None, true_values=None, false_values=None, engine=None, squeeze=False, **kwds)
    Read an Excel table into a pandas DataFrame

    io : string, path object (pathlib.Path or py._path.local.LocalPath),
        file-like object, pandas ExcelFile, or xlrd workbook.
        The string could be a URL. Valid URL schemes include http, ftp, s3,
        and file. For file URLs, a host is expected. For instance, a local
        file could be file://localhost/path/to/workbook.xlsx
    sheetname : string, int, mixed list of strings/ints, or None, default 0

        Strings are used for sheet names, Integers are used in zero-indexed
        sheet positions.

        Lists of strings/integers are used to request multiple sheets.

        Specify None to get all sheets.

        str|int -> DataFrame is returned.
        list|None -> Dict of DataFrames is returned, with keys representing

        Available Cases

        * Defaults to 0 -> 1st sheet as a DataFrame
        * 1 -> 2nd sheet as a DataFrame
        * "Sheet1" -> 1st sheet as a DataFrame
        * [0,1,"Sheet5"] -> 1st, 2nd & 5th sheet as a dictionary of DataFrames
        * None -> All sheets as a dictionary of DataFrames

    header : int, list of ints, default 0
        Row (0-indexed) to use for the column labels of the parsed
        DataFrame. If a list of integers is passed those row positions will
        be combined into a ``MultiIndex``
    skiprows : list-like
        Rows to skip at the beginning (0-indexed)
    skip_footer : int, default 0
        Rows at the end to skip (0-indexed)
    index_col : int, list of ints, default None
        Column (0-indexed) to use as the row labels of the DataFrame.
        Pass None if there is no such column.  If a list is passed,
        those columns will be combined into a ``MultiIndex``
    names : array-like, default None
        List of column names to use. If file contains no header row,
        then you should explicitly pass header=None
    converters : dict, default None
        Dict of functions for converting values in certain columns. Keys can
        either be integers or column labels, values are functions that take one
        input argument, the Excel cell content, and return the transformed
    true_values : list, default None
        Values to consider as True

        .. versionadded:: 0.19.0

    false_values : list, default None
        Values to consider as False

        .. versionadded:: 0.19.0

    parse_cols : int or list, default None
        * If None then parse all columns,
        * If int then indicates last column to be parsed
        * If list of ints then indicates list of column numbers to be parsed
        * If string then indicates comma separated list of column names and
          column ranges (e.g. "A:E" or "A,C,E:F")
    squeeze : boolean, default False
        If the parsed data only contains one column then return a Series
    na_values : scalar, str, list-like, or dict, default None
        Additional strings to recognize as NA/NaN. If dict passed, specific
        per-column NA values. By default the following values are interpreted
        as NaN: '', '#N/A', '#N/A N/A', '#NA', '-1.#IND', '-1.#QNAN', '-NaN', '-nan',
    '1.#IND', '1.#QNAN', 'N/A', 'NA', 'NULL', 'NaN', 'nan'.
    thousands : str, default None
        Thousands separator for parsing string columns to numeric.  Note that
        this parameter is only necessary for columns stored as TEXT in Excel,
        any numeric columns will automatically be parsed, regardless of display
    keep_default_na : bool, default True
        If na_values are specified and keep_default_na is False the default NaN
        values are overridden, otherwise they're appended to.
    verbose : boolean, default False
        Indicate number of NA values placed in non-numeric columns
    engine: string, default None
        If io is not a buffer or path, this must be set to identify io.
        Acceptable values are None or xlrd
    convert_float : boolean, default True
        convert integral floats to int (i.e., 1.0 --> 1). If False, all numeric
        data will be read in as floats: Excel stores all numbers as floats
    has_index_names : boolean, default None
        DEPRECATED: for version 0.17+ index names will be automatically
        inferred based on index_col.  To read Excel output from 0.16.2 and
        prior that had saved index names, use True.

    parsed : DataFrame or Dict of DataFrames
        DataFrame from the passed in Excel file.  See notes in sheetname
        argument for more information on when a Dict of Dataframes is returned.

What is the best way to left align and right align two div tags?

#div1, #div2 {
   float: left; /* or right */

Measuring text height to be drawn on Canvas ( Android )

You could use the android.text.StaticLayout class to specify the bounds required and then call getHeight(). You can draw the text (contained in the layout) by calling its draw(Canvas) method.

How to SFTP with PHP?

The ssh2 functions aren't very good. Hard to use and harder yet to install, using them will guarantee that your code has zero portability. My recommendation would be to use phpseclib, a pure PHP SFTP implementation.

How to change the background colour's opacity in CSS

Use rgba as most of the commonly used browsers supports it..

.social img:hover {
 background-color: rgba(0, 0, 0, .5)

Using FileSystemWatcher to monitor a directory

The problem was the notify filters. The program was trying to open a file that was still copying. I removed all of the notify filters except for LastWrite.

private void watch()
  FileSystemWatcher watcher = new FileSystemWatcher();
  watcher.Path = path;
  watcher.NotifyFilter = NotifyFilters.LastWrite;
  watcher.Filter = "*.*";
  watcher.Changed += new FileSystemEventHandler(OnChanged);
  watcher.EnableRaisingEvents = true;

How do you make div elements display inline?

You need to contain the three divs. Here is an example:


  border: none;
  height: auto;
  width: auto;
  float: left;

div.contain div
  padding: 15px;
  margin: auto;
  border:1px solid red;
  -moz-border-radius:25px; /* Firefox */

Note: border-radius attributes are optional and only work in CSS3 compliant browsers.


<div class="contain">

<div class="contain">

<div class="contain">

Note that the divs 'foo' 'bar' and 'baz' are each held within the 'contain' div.

rails generate model

The code is okay but you are in the wrong directory. You must run these commands inside your rails project-directory.

The normal way to get there from scratch is:

$ rails new PROJECT_NAME
$ rails generate model ad \
    name:string \ 
    description:text \
    price:decimal \
    seller_id:integer \
    email:string img_url:string

Oracle: How to find out if there is a transaction pending?

Matthew Watson can be modified to be used in RAC

select t.inst_id 
from gv$transaction t
inner join gv$session s on t.addr = s.taddr;

Java Comparator class to sort arrays

Just tried this solution, we don't have to even write int.

int[][] twoDim = { { 1, 2 }, { 3, 7 }, { 8, 9 }, { 4, 2 }, { 5, 3 } };
Arrays.sort(twoDim, (a1,a2) -> a2[0] - a1[0]);

This thing will also work, it automatically detects the type of string.

Displaying Image in Java

If you want to load/process/display images I suggest you use an image processing framework. Using Marvin, for instance, you can do that easily with just a few lines of source code.

Source code:

public class Example extends JFrame{

    MarvinImagePlugin prewitt           = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.edge.prewitt");
    MarvinImagePlugin errorDiffusion    = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.halftone.errorDiffusion");
    MarvinImagePlugin emboss            = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.color.emboss");

    public Example(){

        // Layout
        setLayout(new GridLayout(2,2));

        // Load images
        MarvinImage img1 = MarvinImageIO.loadImage("./res/car.jpg");
        MarvinImage img2 = new MarvinImage(img1.getWidth(), img1.getHeight());
        MarvinImage img3 = new MarvinImage(img1.getWidth(), img1.getHeight());
        MarvinImage img4 = new MarvinImage(img1.getWidth(), img1.getHeight());

        // Image Processing plug-ins
        errorDiffusion.process(img1, img2);
        prewitt.process(img1, img3);
        emboss.process(img1, img4);

        // Set panels


    public void addPanel(MarvinImage image){
        MarvinImagePanel imagePanel = new MarvinImagePanel();

    public static void main(String[] args) {
        new Example().setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


enter image description here

How to get first two characters of a string in oracle query?

select substr(orderno,1,2) from shipment;

You may want to have a look at the documentation too.

Undefined reference to `sin`

You need to link with the math library, libm:

$ gcc -Wall foo.c -o foo -lm 

Deserializing JSON data to C# using JSON.NET

Assuming your sample data is correct, your givenname, and other entries wrapped in brackets are arrays in JS... you'll want to use List for those data types. and List for say accountstatusexpmaxdate... I think you example has the dates incorrectly formatted though, so uncertain as to what else is incorrect in your example.

This is an old post, but wanted to make note of the issues.

jQuery .ready in a dynamically inserted iframe

Found the solution to the problem.

When you click on a thickbox link that open a iframe, it insert an iframe with an id of TB_iframeContent.

Instead of relying on the $(document).ready event in the iframe code, I just have to bind to the load event of the iframe in the parent document:

$('#TB_iframeContent', top.document).load(ApplyGalleria);

This code is in the iframe but binds to an event of a control in the parent document. It works in FireFox and IE.

Passing data to a jQuery UI Dialog

A solution inspired by Boris Guery that I employed looks like this: The link:

<a href="#" class = "remove {id:15} " id = "mylink1" >This is my clickable link</a>

bind an action to it:

            var data = $('#';
            var id =;
            var name =;
                .data('id', id)
            return false;

And then to access the id field (in this case with value of 15:

    autoOpen: false,
    width: 345,
    resizable: false,
    draggable: false,
    modal: true,
    buttons: {            
        Cancel: function() {

        'Confirm delete': function() {
            var id = $(this).data('id');
                dataType: "json",


Java Reflection Performance

Interestingly enough, settting setAccessible(true), which skips the security checks, has a 20% reduction in cost.

Without setAccessible(true)

new A(), 70 ns
A.class.newInstance(), 214 ns
new A(), 84 ns
A.class.newInstance(), 229 ns

With setAccessible(true)

new A(), 69 ns
A.class.newInstance(), 159 ns
new A(), 85 ns
A.class.newInstance(), 171 ns

How can I check if a command exists in a shell script?

Try using type:

type foobar

For example:

$ type ls
ls is aliased to `ls --color=auto'

$ type foobar
-bash: type: foobar: not found

This is preferable to which for a few reasons:

  1. The default which implementations only support the -a option that shows all options, so you have to find an alternative version to support aliases

  2. type will tell you exactly what you are looking at (be it a Bash function or an alias or a proper binary).

  3. type doesn't require a subprocess

  4. type cannot be masked by a binary (for example, on a Linux box, if you create a program called which which appears in path before the real which, things hit the fan. type, on the other hand, is a shell built-in (yes, a subordinate inadvertently did this once).

Serialize and Deserialize Json and Json Array in Unity

To Read JSON File, refer this simple example

Your JSON File (StreamingAssets/Player.json)

    "Name": "MyName",
    "Level": 4

C# Script

public class Demo
    public void ReadJSON()
        string path = Application.streamingAssetsPath + "/Player.json";
        string JSONString = File.ReadAllText(path);
        Player player = JsonUtility.FromJson<Player>(JSONString);

public class Player
    public string Name;
    public int Level;

Laravel Eloquent groupBy() AND also return count of each group

If you want to get sorted data use this also

$category_id = Post::orderBy('count', 'desc')
                     ->select(DB::raw('category_id,count(*) as count'))

SSH Port forwarding in a ~/.ssh/config file?

You can use the LocalForward directive in your host yam section of ~/.ssh/config:

LocalForward 5901

Presto SQL - Converting a date string to date format

SQL 2003 standard defines the format as follows:

<unquoted timestamp string> ::= <unquoted date string> <space> <unquoted time string>
<date value> ::= <years value> <minus sign> <months value> <minus sign> <days value>
<time value> ::= <hours value> <colon> <minutes value> <colon> <seconds value>

There are some definitions in between that just link back to these, but in short YYYY-MM-DD HH:MM:SS with optional .mmm milliseconds is required to work on all SQL databases.

How to set the context path of a web application in Tomcat 7.0

Tomcat 8 : After many searches this is only working code: in server.xml

<!-- Set /apple as default path -->
    <Host name="localhost"  appBase="webapps"
         unpackWARs="true" autoDeploy="true">
     <Context path="" docBase="apple">
         <!-- Default set of monitored resources -->

Restart Tomcat, make sure when you access, it will display the content in

My project was java web application witch created by netbeans ,I set context path in project configuration, no other thing, even I put apple.war in webapps folder.

How to check if an option is selected?

If you're not familiar or comfortable with is(), you could just check the value of prop("selected").

As seen here:

$('#mySelectBox option').each(function() {
    if ($(this).prop("selected") == true) {
       // do something
    } else {
       // do something


As @gdoron pointed out in the comments, the faster and most appropriate way to access the selected property of an option is via the DOM selector. Here is the fiddle update displaying this action.

if (this.selected == true) {

appears to work just as well! Thanks gdoron.

How can I view the contents of an ElasticSearch index?

You can even add the size of the terms (indexed terms). Have a look at Elastic Search: how to see the indexed data

How can you get the active users connected to a postgreSQL database via SQL?

(question) Don't you get that info in

select * from pg_user;

or using the view pg_stat_activity:

select * from pg_stat_activity;


the view says:

One row per server process, showing database OID, database name, process ID, user OID, user name, current query, query's waiting status, time at which the current query began execution, time at which the process was started, and client's address and port number. The columns that report data on the current query are available unless the parameter stats_command_string has been turned off. Furthermore, these columns are only visible if the user examining the view is a superuser or the same as the user owning the process being reported on.

can't you filter and get that information? that will be the current users on the Database, you can use began execution time to get all queries from last 5 minutes for example...

something like that.

How to enumerate an enum

I think its help you try it.

public class Program

    public static List<T> GetEnamList<T>()
        var enums = Enum.GetValues(typeof(T)).Cast<T>().Select(v => v).ToList();
        return enums;
    private void LoadEnumList()
        List<DayofWeek> dayofweeks = GetEnamList<DayofWeek>();

        foreach (var item in dayofweeks)

    public enum DayofWeek

How to pass a URI to an intent?

here how I use it; This button inside my CameraActionActivity Activity class where I call camera

 btn_frag_camera.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Intent intenImatToSec = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
                startActivityForResult(intenImatToSec, REQUEST_CODE_VIDEO);
                //intenImatToSec.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);
                //intenImatToSec.putExtra(MediaStore.EXTRA_DURATION_LIMIT, 10);
                //Toast.makeText(getActivity(), "Hello From Camera", Toast.LENGTH_SHORT).show();

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK) {

            if (requestCode == REQUEST_CODE_IMG) {
                Bundle bundle = data.getExtras();
                Bitmap bitmap = (Bitmap) bundle.get("data");
                Intent intentBitMap = new Intent(getActivity(), DisplayImage.class);
                // aldigimiz imagi burda yonlendirdigimiz sinifa iletiyoruz
                ByteArrayOutputStream _bs = new ByteArrayOutputStream();
                bitmap.compress(Bitmap.CompressFormat.PNG, 50, _bs);
                intentBitMap.putExtra("byteArray", _bs.toByteArray());

            } else if (requestCode == REQUEST_CODE_VIDEO) {
                Uri videoUrl = data.getData();
                Intent intenToDisplayVideo = new Intent(getActivity(), DisplayVideo.class);
                intenToDisplayVideo.putExtra("videoUri", videoUrl.toString());

And my other DisplayVideo Activity Class

VideoView videoView = (VideoView) findViewById(;
Bundle extras = getIntent().getExtras();
        Uri myUri=  Uri.parse(extras.getString("videoUri"));

How do I edit a file after I shell to a Docker container?

For common edit operations I prefer to install vi (vim-tiny), which uses only 1491 kB or nano which uses 1707 kB.

In other hand vim uses 28.9 MB.

We have to remember that in order for apt-get install to work, we have to do the update the first time, so:

apt-get update
apt-get install vim-tiny

To start the editor in CLI we need to enter vi.

First letter capitalization for EditText

If you want capital first letter in every word then use android:inputType="textCapWords"

For Better understanding


And if you capital word for every sentence then use it . android:inputType="textCapSentences" this line in your xml. I mean in your EditText.

For Better understanding


Read .doc file with python

You can use python-docx2txt library to read text from Microsoft Word documents. It is an improvement over python-docx library as it can, in addition, extract text from links, headers and footers. It can even extract images.

You can install it by running: pip install docx2txt.

Let's download and read the first Microsoft document on here:

import docx2txt
my_text = docx2txt.process("test.docx")

Here is a screenshot of the Terminal output the above code:

enter image description here


This does NOT work for .doc files. The only reason I am keep this answer is that it seems there are people who find it useful for .docx files.

Creating lowpass filter in SciPy - understanding methods and units

A few comments:

  • The Nyquist frequency is half the sampling rate.
  • You are working with regularly sampled data, so you want a digital filter, not an analog filter. This means you should not use analog=True in the call to butter, and you should use scipy.signal.freqz (not freqs) to generate the frequency response.
  • One goal of those short utility functions is to allow you to leave all your frequencies expressed in Hz. You shouldn't have to convert to rad/sec. As long as you express your frequencies with consistent units, the scaling in the utility functions takes care of the normalization for you.

Here's my modified version of your script, followed by the plot that it generates.

import numpy as np
from scipy.signal import butter, lfilter, freqz
import matplotlib.pyplot as plt

def butter_lowpass(cutoff, fs, order=5):
    nyq = 0.5 * fs
    normal_cutoff = cutoff / nyq
    b, a = butter(order, normal_cutoff, btype='low', analog=False)
    return b, a

def butter_lowpass_filter(data, cutoff, fs, order=5):
    b, a = butter_lowpass(cutoff, fs, order=order)
    y = lfilter(b, a, data)
    return y

# Filter requirements.
order = 6
fs = 30.0       # sample rate, Hz
cutoff = 3.667  # desired cutoff frequency of the filter, Hz

# Get the filter coefficients so we can check its frequency response.
b, a = butter_lowpass(cutoff, fs, order)

# Plot the frequency response.
w, h = freqz(b, a, worN=8000)
plt.subplot(2, 1, 1)
plt.plot(0.5*fs*w/np.pi, np.abs(h), 'b')
plt.plot(cutoff, 0.5*np.sqrt(2), 'ko')
plt.axvline(cutoff, color='k')
plt.xlim(0, 0.5*fs)
plt.title("Lowpass Filter Frequency Response")
plt.xlabel('Frequency [Hz]')

# Demonstrate the use of the filter.
# First make some data to be filtered.
T = 5.0         # seconds
n = int(T * fs) # total number of samples
t = np.linspace(0, T, n, endpoint=False)
# "Noisy" data.  We want to recover the 1.2 Hz signal from this.
data = np.sin(1.2*2*np.pi*t) + 1.5*np.cos(9*2*np.pi*t) + 0.5*np.sin(12.0*2*np.pi*t)

# Filter the data, and plot both the original and filtered signals.
y = butter_lowpass_filter(data, cutoff, fs, order)

plt.subplot(2, 1, 2)
plt.plot(t, data, 'b-', label='data')
plt.plot(t, y, 'g-', linewidth=2, label='filtered data')
plt.xlabel('Time [sec]')


lowpass example

Android: how to draw a border to a LinearLayout

Do you really need to do that programmatically?

Just considering the title: You could use a ShapeDrawable as android:background…

For example, let's define res/drawable/my_custom_background.xml as:

<shape xmlns:android=""
      android:bottomLeftRadius="0dp" />
      android:color="@android:color/white" />

and define android:background="@drawable/my_custom_background".

I've not tested but it should work.


I think that's better to leverage the xml shape drawable resource power if that fits your needs. With a "from scratch" project (for android-8), define res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""
    android:padding="10dip" >
        android:text="Hello World, SOnich"
    [... more TextView ...]
        android:text="Hello World, SOnich"

and a res/drawable/border.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android=""
        android:color="@android:color/white" />

Reported to work on a gingerbread device. Note that you'll need to relate android:padding of the LinearLayout to the android:width shape/stroke's value. Please, do not use @android:color/white in your final application but rather a project defined color.

You could apply android:background="@drawable/border" android:padding="10dip" to each of the LinearLayout from your provided sample.

As for your other posts related to display some circles as LinearLayout's background, I'm playing with Inset/Scale/Layer drawable resources (see Drawable Resources for further information) to get something working to display perfect circles in the background of a LinearLayout but failed at the moment…

Your problem resides clearly in the use of getBorder.set{Width,Height}(100);. Why do you do that in an onClick method?

I need further information to not miss the point: why do you do that programmatically? Do you need a dynamic behavior? Your input drawables are png or ShapeDrawable is acceptable? etc.

To be continued (maybe tomorrow and as soon as you provide more precisions on what you want to achieve)…

How to enable assembly bind failure logging (Fusion) in .NET

I wrote an assembly binding log viewer named Fusion++ and put it on GitHub.

You can get the latest release from here or via chocolatey (choco install fusionplusplus).

I hope you and some of the visitors in here can save some worthy lifetime minutes with it.


CSS filter: make color image with transparency white

To my knowledge, there is sadly no CSS filter to colorise an element (perhaps with the use of some SVG filter magic, but I'm somewhat unfamiliar with that) and even if that wasn't the case, filters are basically only supported by webkit browsers.

With that said, you could still work around this and use a canvas to modify your image. Basically, you can draw an image element onto a canvas and then loop through the pixels, modifying the respective RGBA values to the colour you want.

However, canvases do come with some restrictions. Most importantly, you have to make sure that the image src comes from the same domain as the page. Otherwise the browser won't allow you to read or modify the pixel data of the canvas.

Here's a JSFiddle changing the colour of the JSFiddle logo.

//Base64 source, but any local source will work_x000D_
var src = "data:image/png;base64,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";_x000D_
var canvas = document.getElementById("theCanvas");_x000D_
var ctx = canvas.getContext("2d");_x000D_
var img = new Image;_x000D_
//wait for the image to load_x000D_
img.onload = function() {_x000D_
    //Draw the original image so that you can fetch the colour data_x000D_
    var imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);_x000D_
    /*_x000D_ is a one-dimensional array which contains _x000D_
    the respective RGBA values for every pixel _x000D_
    in the selected region of the context _x000D_
    (note i+=4 in the loop)_x000D_
    for (var i = 0; i <; i+=4) {_x000D_[i] = 255; //Red, 0-255_x000D_[i+1] = 255; //Green, 0-255_x000D_[i+2] = 255; //Blue, 0-255_x000D_
   /* _x000D_[i+3] contains the alpha value_x000D_
   which we are going to ignore and leave_x000D_
   alone with its original value_x000D_
    ctx.clearRect(0, 0, canvas.width, canvas.height); //clear the original image_x000D_
    ctx.putImageData(imgData, 0, 0); //paint the new colorised image_x000D_
//Load the image!_x000D_
img.src = src;
body {_x000D_
    background: green;_x000D_
<canvas id="theCanvas"></canvas>

Adding images to an HTML document with javascript

You need to use document.getElementById() in line 3.

If you try this right now in the console:

var img = document.createElement("img");_x000D_
img.src = "";_x000D_
var src = document.getElementById("header");_x000D_
<div id="header"></div>

... you'd get this:

enter image description here

Basic Python client socket example

You might be confusing compilation from execution. Python has no compilation step! :) As soon as you type python the program runs and, in your case, tries to connect to an open port 5000, giving an error if no server program is listening there. It sounds like you are familiar with two-step languages, that require compilation to produce an executable — and thus you are confusing Python's runtime compilaint that “I can't find anyone listening on port 5000!” with a compile-time error. But, in fact, your Python code is fine; you just need to bring up a listener before running it!

Reducing MongoDB database file size

We need solve 2 ways, based on StorageEngine.

1. MMAP() engine:

command: db.repairDatabase()

NOTE: repairDatabase requires free disk space equal to the size of your current data set plus 2 gigabytes. If the volume that holds dbpath lacks sufficient space, you can mount a separate volume and use that for the repair. When mounting a separate volume for repairDatabase you must run repairDatabase from the command line and use the --repairpath switch to specify the folder in which to store temporary repair files. eg: Imagine DB size is 120 GB means, (120*2)+2 = 242 GB Hard Disk space required.

another way you do collection wise, command: db.runCommand({compact: 'collectionName'})

2. WiredTiger: Its automatically resolved it-self.

Add a link to an image in a css style sheet

You don't add links to style sheets. They are for describing the style of the page. You would change your mark-up or add JavaScript to navigate when the image is clicked.

Based only on your style you would have:

<a href="" id="logo"></a>

How to get a key in a JavaScript object by its value?

I use this function:

Object.prototype.getKey = function(value){
  for(var key in this){
    if(this[key] == value){
      return key;
  return null;


// ISO 639: 2-letter codes
var languageCodes = {
  DA: 'Danish',
  DE: 'German',
  DZ: 'Bhutani',
  EL: 'Greek',
  EN: 'English',
  EO: 'Esperanto',
  ES: 'Spanish'

var key = languageCodes.getKey('Greek');
console.log(key); // EL

Select <a> which href ends with some string


Selector documentation can be found at

For attributes:

= is exactly equal
!= is not equal
^= is starts with
$= is ends with
*= is contains
~= is contains word
|= is starts with prefix (i.e., |= "prefix" matches "prefix-...")

EF 5 Enable-Migrations : No context type was found in the assembly

Adding a class which inherits DbContext resolved my problem:

public class MyDbContext : DbContext { public MyDbContext() { } }

How to both read and write a file in C#

you can try this:"Filename.txt" file will be created automatically in the bin->debug folder everytime you run this code or you can specify path of the file like: @"C:/...". you can check ëxistance of "Hello" by going to the bin -->debug folder

P.S dont forget to add Console.Readline() after this code snippet else console will not appear.

TextWriter tw = new StreamWriter("filename.txt");
        String text = "Hello";

        TextReader tr = new StreamReader("filename.txt");

Select2 doesn't work when embedded in a bootstrap modal

Based on @pymarco answer I wrote this solution, it's not perfect but solves the select2 focus problem and maintain tab sequence working inside modal

    $.fn.modal.Constructor.prototype.enforceFocus = function () {
        .off('') // guard against infinite focus loop
        .on('', $.proxy(function (e) {
            if (this.$element[0] !== && !this.$element.has( && !$('.select2-dropdown').length) {
        }, this))

How to compare two double values in Java?

Just use method to compare double values.,d2) == 0)

double d1 = 0.0;
double d2 = 0.0;

System.out.println(,d2) == 0))  // true

Styling multi-line conditions in 'if' statements?

Here's my very personal take: long conditions are (in my view) a code smell that suggests refactoring into a boolean-returning function/method. For example:

def is_action__required(...):
    return (cond1 == 'val1' and cond2 == 'val2'
            and cond3 == 'val3' and cond4 == 'val4')

Now, if I found a way to make multi-line conditions look good, I would probably find myself content with having them and skip the refactoring.

On the other hand, having them perturb my aesthetic sense acts as an incentive for refactoring.

My conclusion, therefore, is that multiple line conditions should look ugly and this is an incentive to avoid them.

Can not get a simple bootstrap modal to work

A better solution is to load a twisted version of bootstrap.js without jquery. Get it from

<script src=".../bootstrap-without-jquery.min.js"></script>

Going this way will save you trouble from script tags.

How to suppress "unused parameter" warnings in C?

In gcc, you can label the parameter with the unused attribute.

This attribute, attached to a variable, means that the variable is meant to be possibly unused. GCC will not produce a warning for this variable.

In practice this is accomplished by putting __attribute__ ((unused)) just before the parameter. For example:

void foo(workerid_t workerId) { }


void foo(__attribute__((unused)) workerid_t workerId) { }

Parsing string as JSON with single quotes?

json = ( new Function("return " + jsonString) )(); 

Git fetch remote branch

What helped me was

1) To view all available remote branches (e.g. 'remote-branch-name')

git branch -r

2) Create a local branch using remote branch name

git fetch && git checkout 'remote-branch-name'

Removing rounded corners from a <select> element in Chrome/Webkit

well i got the solution. hope it may help you :)

      border-image: url( 30 stretch;_x000D_
      width: 120px;_x000D_
      height: 36px;_x000D_
      color: #999;_x000D_
  <option value="1">Hi</option>_x000D_
  <option value="2">Bye</option>_x000D_

How to check object is nil or not in swift?

If abc is an optional, then the usual way to do this would be to attempt to unwrap it in an if statement:

if let variableName = abc { // If casting, use, eg, if let var = abc as? NSString
    // variableName will be abc, unwrapped
} else {
    // abc is nil

However, to answer your actual question, your problem is that you're typing the variable such that it can never be optional.

Remember that in Swift, nil is a value which can only apply to optionals.

Since you've declared your variable as:

var abc: NSString ...

it is not optional, and cannot be nil.

Try declaring it as:

var abc: NSString? ...

or alternatively letting the compiler infer the type.

How do you join on the same table, twice, in mysql?

Read this and try, this will help you:





SELECT table1.column11,table1.column12,table2asnew1.column21,table2asnew2.column21 
FROM table1 INNER JOIN table2 AS table2asnew1 ON table1.column11=table2asnew1.column21  INNER TABLE table2 as table2asnew2 ON table1.column12=table2asnew2.column22

table2asnew1 is an instance of table 2 which is matched by table1.column11=table2asnew1.column21


table2asnew2 is another instance of table 2 which is matched by table1.column12=table2asnew2.column22

How to set button click effect in Android?

For all the views


But for cardview which has elevation use


For Circular click effect as in toolbar


Also you need to set


App.Config file in console application C#

You can add a reference to System.Configuration in your project and then:

using System.Configuration;


string sValue = ConfigurationManager.AppSettings["BatchFile"];

with an app.config file like this:

<?xml version="1.0" encoding="utf-8" ?>
       <add key="BatchFile" value="blah.bat" />

How to retrieve an Oracle directory path?

The ALL_DIRECTORIES data dictionary view will have information about all the directories that you have access to. That includes the operating system path

SELECT owner, directory_name, directory_path
  FROM all_directories

The project description file (.project) for my project is missing

Martin Encountered the same issue with a Minecraft Mod project when I changed the Main folder location. Normally I would open the project like this

This is how my path looked when I started the project

I got the same "The project description file (.project) for my project is missing." Error.

I later found the .project file in the main folder like this.

This is the location where I found the .project file

I found that going eclipse to "File->Open Project from File System or Archive" and navigate to your main project folder with the .project file solved the problem.

My project is already included

This is my first post in here hoping it can help you out, Martin.

Xcode 'CodeSign error: code signing is required'

After trying all of the above answers, and everything else I could think of from within Xcode 4.6, I fixed this with these steps:

  1. Close Xcode
  2. Right-click on .xcodeproj file -> show package contents
  3. Edit project.xcodeproj in a text editor
  4. Search for "CODE_SIGN_IDENTITY" - there will be pairs of lines like this:
 CODE_SIGN_IDENTITY = "iPhone Developer: Joe Smith (555NN555)";
 "CODE_SIGN_IDENTY[sdk=iphoneos*]" = "iPhone Developer: Joe Smith (555NN555)";

I found 2 targets with value like that, and 2 targets with

 "CODE_SIGN_IDENTY[sdk=iphoneos*]" = "";

I copied the former pair of lines over the latter pair of lines for all cases where the latter pair was emtpy.

I then restarted Xcode, and it works fine now.

How to encrypt and decrypt file in Android?

You could use java-aes-crypto or Facebook's Conceal


Quoting from the repo

A simple Android class for encrypting & decrypting strings, aiming to avoid the classic mistakes that most such classes suffer from.

Facebook's conceal

Quoting from the repo

Conceal provides easy Android APIs for performing fast encryption and authentication of data

Is there a naming convention for git repositories?

I'd go for purchase-rest-service. Reasons:

  1. What is "pur chase rests ervice"? Long, concatenated words are hard to understand. I know, I'm German. "Donaudampfschifffahrtskapitänspatentausfüllungsassistentenausschreibungsstellenbewerbung."

  2. "_" is harder to type than "-"

SCRIPT7002: XMLHttpRequest: Network Error 0x2ef3, Could not complete the operation due to error 00002ef3

This issue happened in my project because of an ajax GET call with a long xml string as a parameter value. Solved by the following approach: Making it as ajax post call to Java Spring MVC controller class method like this.

    url: "controller_Method_Name.html?variable_name="+variable_value,
    type: "POST",
            "xmlMetaData": xmlMetaData // This variable contains a long xml string
    success: function(response)

Inside Spring MVC Controller class method:

  public void controller_Method_Name(@RequestParam("xmlMetaData") String metaDataXML, HttpServletRequest request)

What exactly does numpy.exp() do?

The exponential function is e^x where e is a mathematical constant called Euler's number, approximately 2.718281. This value has a close mathematical relationship with pi and the slope of the curve e^x is equal to its value at every point. np.exp() calculates e^x for each value of x in your input array.

uint8_t vs unsigned char

There's little. From portability viewpoint, char cannot be smaller than 8 bits, and nothing can be smaller than char, so if a given C implementation has an unsigned 8-bit integer type, it's going to be char. Alternatively, it may not have one at all, at which point any typedef tricks are moot.

It could be used to better document your code in a sense that it's clear that you require 8-bit bytes there and nothing else. But in practice it's a reasonable expectation virtually anywhere already (there are DSP platforms on which it's not true, but chances of your code running there is slim, and you could just as well error out using a static assert at the top of your program on such a platform).

Loading custom functions in PowerShell

I kept using this all this time

Import-module .\build_functions.ps1 -Force

"Bitmap too large to be uploaded into a texture"

All rendering is based on OpenGL, so no you can't go over this limit (GL_MAX_TEXTURE_SIZE depends on the device, but the minimum is 2048x2048, so any image lower than 2048x2048 will fit).

With such big images, if you want to zoom in out, and in a mobile, you should setup a system similar to what you see in google maps for example. With the image split in several pieces, and several definitions.

Or you could scale down the image before displaying it (see user1352407's answer on this question).

And also, be careful to which folder you put the image into, Android can automatically scale up images. Have a look at Pilot_51's answer below on this question.

Run a single test method with maven

New versions of JUnit contains the Categories runner:

But releasing procedure of JUnit is not maven based, so maven users have to put it manually to their repositories.

How to import a module given its name as string?

You can use exec:

exec("import myapp.commands.%s" % command)

Correctly Parsing JSON in Swift 3

The problem is with the API interaction method. The JSON parsing is changed only in syntax. The main problem is with the way of fetching data. What you are using is a synchronous way of getting data. This doesn't work in every case. What you should be using is an asynchronous way to fetch data. In this way, you have to request data through the API and wait for it to respond with data. You can achieve this with URL session and third party libraries like Alamofire. Below is the code for URL Session method.

let urlString = ",122.048951"
let url = URL.init(string: urlString)
URLSession.shared.dataTask(with:url!) { (data, response, error) in
    guard error == nil else {
    do {
        let Data = try JSONSerialization.jsonObject(with: data!) as! [String:Any]
        // Note if your data is coming in Array you should be using [Any]()
        //Now your data is parsed in Data variable and you can use it normally
        let currentConditions = Data["currently"] as! [String:Any]
        let currentTemperatureF = currentConditions["temperature"] as! Double
    } catch let error as NSError {

Quickly create a large file on a Linux system

Linux & all filesystems

xfs_mkfile 10240m 10Gigfile

Linux & and some filesystems (ext4, xfs, btrfs and ocfs2)

fallocate -l 10G 10Gigfile

OS X, Solaris, SunOS and probably other UNIXes

mkfile 10240m 10Gigfile


prealloc 10Gigfile 10737418240


Try mkfile <size> myfile as an alternative of dd. With the -n option the size is noted, but disk blocks aren't allocated until data is written to them. Without the -n option, the space is zero-filled, which means writing to the disk, which means taking time.

mkfile is derived from SunOS and is not available everywhere. Most Linux systems have xfs_mkfile which works exactly the same way, and not just on XFS file systems despite the name. It's included in xfsprogs (for Debian/Ubuntu) or similar named packages.

Most Linux systems also have fallocate, which only works on certain file systems (such as btrfs, ext4, ocfs2, and xfs), but is the fastest, as it allocates all the file space (creates non-holey files) but does not initialize any of it.

Example of a strong and weak entity types


It probably can be written in two factors:

  • DEPENDENCE: Depends on the existence of an identifying entity set (total, one-to-many relationship).
  • IDENTIFICATION: Does not have a primary key. It has a partial key (or discriminator). It needs to use the primary key of another table for identification.

If we would think of a database holding questions and answers, then the questions would be the strong entity and the answers would be the weak entity. So, Question (id, text) and Answer (number, question_id, text) would be our tables. But why is the Answer's table a weak entity?

  • Dependence to the question table. Every answer is connected to one question (assumption) and so it cannot be on its own. That is why we have people who ask one question and answer it themselves so that they can help other people and get some extra likings.

  • Identification from the primary key of the question. One would not be able to identify an answer (assuming that its id is a number identifier) because a question might be answered by answers whose identifier might exist in other questions too. Primary key of the answer table: (number, question_id).

How to make custom error pages work in ASP.NET MVC 4

I would Recommend to use Global.asax.cs File.

 protected void Application_Error(Object sender, EventArgs e)
    var exception = Server.GetLastError();
    if (exception is HttpUnhandledException)
    if (exception != null)
        // This is to stop a problem where we were seeing "gibberish" in the
        // chrome and firefox browsers
        HttpApplication app = sender as HttpApplication;
        app.Response.Filter = null;

Setting font on NSAttributedString on UITextView disregards line spacing

You can use this example and change it's implementation like this:

[self enumerateAttribute:NSParagraphStyleAttributeName
                 inRange:NSMakeRange(0, self.length)
              usingBlock:^(id  _Nullable value, NSRange range, BOOL * _Nonnull stop) {
                  NSMutableParagraphStyle *paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];

                  //add your specific settings for paragraph

                  [self removeAttribute:NSParagraphStyleAttributeName range:range];
                  [self addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:range];

How do I capture response of form.submit

You can do that using javascript and AJAX technology. Have a look at jquery and at this form plug in. You only need to include two js files to register a callback for the form.submit.

How can I show three columns per row?

Even though the above answer appears to be correct, I wanted to add a (hopefully) more readable example that also stays in 3 columns form at different widths:

.flex-row-container {_x000D_
    background: #aaa;_x000D_
    display: flex;_x000D_
    flex-wrap: wrap;_x000D_
    align-items: center;_x000D_
    justify-content: center;_x000D_
.flex-row-container > .flex-row-item {_x000D_
    flex: 1 1 30%; /*grow | shrink | basis */_x000D_
    height: 100px;_x000D_
.flex-row-item {_x000D_
  background-color: #fff4e6;_x000D_
  border: 1px solid #f76707;_x000D_
<div class="flex-row-container">_x000D_
  <div class="flex-row-item">1</div>_x000D_
  <div class="flex-row-item">2</div>_x000D_
  <div class="flex-row-item">3</div>_x000D_
  <div class="flex-row-item">4</div>_x000D_
  <div class="flex-row-item">5</div>_x000D_
  <div class="flex-row-item">6</div>_x000D_

Hope this helps someone else.

Rendering partial view on button click in ASP.NET MVC

So here is the controller code.

public IActionResult AddURLTest()
    return ViewComponent("AddURL");

You can load it using JQuery load method.

$(document).ready (function(){

source code link

Cannot install node modules that require compilation on Windows 7 x64/VS2012

Thanks to @felixrieseberg, you just need to install windows-build-tools npm package and you are good to go.

npm install --global --production windows-build-tools

You won't need to install Visual Studio.

You won't need to install Microsoft Build Tools.

From the repo:

After installation, npm will automatically execute this module, which downloads and installs Visual C++ Build Tools 2015, provided free of charge by Microsoft. These tools are required to compile popular native modules. It will also install Python 2.7, configuring your machine and npm appropriately.

Windows Vista / 7 requires .NET Framework 4.5.1 (Currently not installed automatically by this package)

Both installations are conflict-free, meaning that they do not mess with existing installations of Visual Studio, C++ Build Tools, or Python.

How to store Java Date to Mysql datetime with JPA

it works for me !!

in mysql table


in entity:

private Date startDate;

in process:

objectEntity.setStartDate(new Date());

in preparedStatement:

pstm.setDate(9, new java.sql.Date(objEntity.getStartDate().getTime()));

PersistentObjectException: detached entity passed to persist thrown by JPA and Hibernate

The solution is simple, just use the CascadeType.MERGE instead of CascadeType.PERSIST or CascadeType.ALL.

I have had the same problem and CascadeType.MERGE has worked for me.

I hope you are sorted.

Display fullscreen mode on Tkinter

I think if you are looking for fullscreen only, no need to set geometry or maxsize etc.

You just need to do this:

-If you are working on ubuntu:

root.attributes('-zoomed', True)

-and if you are working on windows:


Now for toggling between fullscreen, for minimising it to taskbar you can use:


List comprehension vs map

If you plan on writing any asynchronous, parallel, or distributed code, you will probably prefer map over a list comprehension -- as most asynchronous, parallel, or distributed packages provide a map function to overload python's map. Then by passing the appropriate map function to the rest of your code, you may not have to modify your original serial code to have it run in parallel (etc).

How to use __doPostBack()

I'd just like to add something to this post for asp:button. I've tried clientId and it doesn't seem to work for me:

__doPostBack('<%= btn.ClientID%>', '');

However, getting the UniqueId seems to post back to the server, like below:

__doPostBack('<%= btn.UniqueID%>', '');

This might help someone else in future, hence posting this.

Do I use <img>, <object>, or <embed> for SVG files?

If you need your SVGs to be fully styleable with CSS they have to be inline in the DOM. This can be achieved through SVG injection, which uses Javascript to replace a HTML element (usually an <img> element) with the contents of an SVG file after the page has loaded.

Here is a minimal example using SVGInject:

  <script src="svg-inject.min.js"></script>
  <img src="image.svg" onload="SVGInject(this)" />

After the image is loaded the onload="SVGInject(this) will trigger the injection and the <img> element will be replaced by the contents of the file provided in the src attribute. This works with all browsers that support SVG.

Disclaimer: I am the co-author of SVGInject

How to import a new font into a project - Angular 5

You can try creating a css for your font with font-face (like explained here)

Step #1

Create a css file with font face and place it somewhere, like in assets/fonts


@font-face {
    font-family: YourFontFamily;
    src: url("/assets/font/yourFont.otf") format("truetype");

Step #2

Add the css to your .angular-cli.json in the styles config

 //...your other styles

Do not forget to restart ng serve after doing this

Step #3

Use the font in your code


span {font-family: YourFontFamily; }

Is it possible to use jQuery .on and hover?

You can you use .on() with hover by doing what the Additional Notes section says:

Although strongly discouraged for new code, you may see the pseudo-event-name "hover" used as a shorthand for the string "mouseenter mouseleave". It attaches a single event handler for those two events, and the handler must examine event.type to determine whether the event is mouseenter or mouseleave. Do not confuse the "hover" pseudo-event-name with the .hover() method, which accepts one or two functions.

That would be to do the following:

$("#foo").on("hover", function(e) {

    if (e.type === "mouseenter") { console.log("enter"); }
    else if (e.type === "mouseleave") { console.log("leave"); }


EDIT (note for jQuery 1.8+ users):

Deprecated in jQuery 1.8, removed in 1.9: The name "hover" used as a shorthand for the string "mouseenter mouseleave". It attaches a single event handler for those two events, and the handler must examine event.type to determine whether the event is mouseenter or mouseleave. Do not confuse the "hover" pseudo-event-name with the .hover() method, which accepts one or two functions.

PHP Session data not being saved

Had same problem - what happened to me is our server admin changed the session.cookie_secure boolean to On, which means that cookies will only be sent over a secure connection. Since the cookie was not being found, php was creating a new session every time, thus session variables were not being seen.

How to escape regular expression special characters using javascript?

With \ you escape special characters

Escapes special characters to literal and literal characters to special.

E.g: /\(s\)/ matches '(s)' while /(\s)/ matches any whitespace and captures the match.


System.Threading.Timer in C# it seems to be not working. It runs very fast every 3 second

This is not the correct usage of the System.Threading.Timer. When you instantiate the Timer, you should almost always do the following:

_timer = new Timer( Callback, null, TIME_INTERVAL_IN_MILLISECONDS, Timeout.Infinite );

This will instruct the timer to tick only once when the interval has elapsed. Then in your Callback function you Change the timer once the work has completed, not before. Example:

private void Callback( Object state )
    // Long running operation
   _timer.Change( TIME_INTERVAL_IN_MILLISECONDS, Timeout.Infinite );

Thus there is no need for locking mechanisms because there is no concurrency. The timer will fire the next callback after the next interval has elapsed + the time of the long running operation.

If you need to run your timer at exactly N milliseconds, then I suggest you measure the time of the long running operation using Stopwatch and then call the Change method appropriately:

private void Callback( Object state )
   Stopwatch watch = new Stopwatch();

   // Long running operation

   _timer.Change( Math.Max( 0, TIME_INTERVAL_IN_MILLISECONDS - watch.ElapsedMilliseconds ), Timeout.Infinite );

I strongly encourage anyone doing .NET and is using the CLR who hasn't read Jeffrey Richter's book - CLR via C#, to read is as soon as possible. Timers and thread pools are explained in great details there.

How to equalize the scales of x-axis and y-axis in Python matplotlib?

Try something like:

import pylab as p

How to add target="_blank" to JavaScript window.location?

    var linkGo = function(item) {_x000D_
      $(item).on('click', function() {_x000D_
        var _$this = $(this);_x000D_
        var _urlBlank = _$this.attr("data-link");_x000D_
        var _urlTemp = _$this.attr("data-url");_x000D_
        if (_urlBlank === "_blank") {_x000D_
, '_blank');_x000D_
        } else {_x000D_
          // cross-origin_x000D_
          location.href = _urlTemp;_x000D_
<script src=""></script>_x000D_
<span class="button button__main" data-link="" data-url="">go stackoverflow</span>

Checking if any elements in one list are in another

You could solve this many ways. One that is pretty simple to understand is to just use a loop.

def comp(list1, list2):
    for val in list1:
        if val in list2:
            return True
    return False

A more compact way you can do it is to use map and reduce:

reduce(lambda v1,v2: v1 or v2, map(lambda v: v in list2, list1))

Even better, the reduce can be replaced with any:

any(map(lambda v: v in list2, list1))

You could also use sets:

len(set(list1).intersection(list2)) > 0

How to change the background color on a Java panel?

setBackground() is the right method to use. Did you repaint after you changed it? If you change it before you make the panel (or its containing frame) visible it should work

How to convert an integer (time) to HH:MM:SS::00 in SQL Server 2008?

You can use the following time conversion within SQL like this:

--Convert Time to Integer (Minutes)
DECLARE @timeNow datetime = '14:47'
SELECT DATEDIFF(mi,CONVERT(datetime,'00:00',108), CONVERT(datetime, RIGHT(CONVERT(varchar, @timeNow, 100),7),108))

--Convert Minutes to Time
DECLARE @intTime int = (SELECT DATEDIFF(mi,CONVERT(datetime,'00:00',108), CONVERT(datetime, RIGHT(CONVERT(varchar, @timeNow, 100),7),108)))
SELECT DATEADD(minute, @intTime, '')

Result: 887 <- Time in minutes and 1900-01-01 14:47:00.000 <-- Minutes to time

How to check if pytorch is using the GPU?

Create a tensor on the GPU as follows:

$ python
>>> import torch
>>> print(torch.rand(3,3).cuda()) 

Do not quit, open another terminal and check if the python process is using the GPU using:

$ nvidia-smi

External resource not being loaded by AngularJs

Whitelist the resource with $sceDelegateProvider

This is caused by a new security policy put in place in Angular 1.2. It makes XSS harder by preventing a hacker from dialling out (i.e. making a request to a foreign URL, potentially containing a payload).

To get around it properly you need to whitelist the domains you want to allow, like this:

angular.module('myApp',['ngSanitize']).config(function($sceDelegateProvider) {
    // Allow same origin resource loads.
    // Allow loading from our assets domain.  Notice the difference between * and **.

  // The blacklist overrides the whitelist so the open redirect here is blocked.

This example is lifted from the documentation which you can read here:$sceDelegateProvider

Be sure to include ngSanitize in your app to make this work.

Disabling the feature

If you want to turn off this useful feature, and you're sure your data is secure, you can simply allow **, like so:

angular.module('app').config(function($sceDelegateProvider) {

Convert json to a C# array?

Old question but worth adding an answer if using .NET Core 3.0 or later. JSON serialization/deserialization is built into the framework (System.Text.Json), so you don't have to use third party libraries any more. Here's an example based off the top answer given by @Icarus

using System;
using System.Collections.Generic;

namespace ConsoleApp
    class Program
        static void Main(string[] args)
            var json = "[{\"Name\":\"John Smith\", \"Age\":35}, {\"Name\":\"Pablo Perez\", \"Age\":34}]";

            // use the built in Json deserializer to convert the string to a list of Person objects
            var people = System.Text.Json.JsonSerializer.Deserialize<List<Person>>(json);

            foreach (var person in people)
                Console.WriteLine(person.Name + " is " + person.Age + " years old.");

        public class Person
            public int Age { get; set; }
            public string Name { get; set; }

Pass a PHP array to a JavaScript function

Data transfer between two platform requires a common data format. JSON is a common global format to send cross platform data.

drawChart(600/50, JSON.parse('<?php echo json_encode($day); ?>'), JSON.parse('<?php echo json_encode($week); ?>'), JSON.parse('<?php echo json_encode($month); ?>'), JSON.parse('<?php echo json_encode(createDatesArray(cal_days_in_month(CAL_GREGORIAN, date('m',strtotime('-1 day')), date('Y',strtotime('-1 day'))))); ?>'))

This is the answer to your question. The answer may look very complex. You can see a simple example describing the communication between server side and client side here

$employee = array(
 "employee_id" => 10011,
   "Name" => "Nathan",
   "Skills" =>
           "documentation" =>

Conversion to JSON format is required to send the data back to client application ie, JavaScript. PHP has a built in function json_encode(), which can convert any data to JSON format. The output of the json_encode function will be a string like this.

    "employee_id": 10011,
    "Name": "Nathan",
    "Skills": {
        "0": "analyzing",
        "documentation": [

On the client side, success function will get the JSON string. Javascript also have JSON parsing function JSON.parse() which can convert the string back to JSON object.

        type: 'POST',
        headers: {
            "cache-control": "no-cache"
        url: "employee.php",
        async: false,
        cache: false,
        data: {
            employee_id: 10011
        success: function (jsonString) {
            var employeeData = JSON.parse(jsonString); // employeeData variable contains employee array.

How to get exit code when using Python subprocess communicate method?

Use process.wait() after you call process.communicate().
For example:

import subprocess

process = subprocess.Popen(['ipconfig', '/all'], stderr=subprocess.PIPE, stdout=subprocess.PIPE)
stdout, stderr = process.communicate()
exit_code = process.wait()
print(stdout, stderr, exit_code)

In c, in bool, true == 1 and false == 0?

You neglected to say which version of C you are concerned about. Let's assume it's this one:

As you can see by reading the specification, the standard definitions of true and false are 1 and 0, yes.

If your question is about a different version of C, or about non-standard definitions for true and false, then ask a more specific question.

Using the last-child selector

If you are floating the elements you can reverse the order

i.e. float: right; instead of float: left;

And then use this method to select the first-child of a class.

/* 1: Apply style to ALL instances */
#header .some-class {
  padding-right: 0;
/* 2: Remove style from ALL instances except FIRST instance */
#header .some-class~.some-class {
  padding-right: 20px;

This is actually applying the class to the LAST instance only because it's now in reversed order.

Here is a working example for you:

<!doctype html>
<head><title>CSS Test</title>
<style type="text/css">
.some-class { margin: 0; padding: 0 20px; list-style-type: square; }
.lfloat { float: left; display: block; }
.rfloat { float: right; display: block; }
/* apply style to last instance only */
#header .some-class {
  border: 1px solid red;
  padding-right: 0;
#header .some-class~.some-class {
  border: 0;
  padding-right: 20px;
<div id="header">
  <img src="some_image" title="Logo" class="lfloat no-border"/>
  <ul class="some-class rfloat">
    <li>List 1-1</li>
    <li>List 1-2</li>
    <li>List 1-3</li>
  <ul class="some-class rfloat">
    <li>List 2-1</li>
    <li>List 2-2</li>
    <li>List 2-3</li>
  <ul class="some-class rfloat">
    <li>List 3-1</li>
    <li>List 3-2</li>
    <li>List 3-3</li>
  <img src="some_other_img" title="Icon" class="rfloat no-border"/>

Is it possible to get only the first character of a String?

Here I am taking Mobile No From EditText It may start from +91 or 0 but i am getting actual 10 digits. Hope this will help you.

              String mob=edit_mobile.getText().toString();
                    if (mob.length() >= 10) {
                        if (mob.contains("+91")) {
                            mob= mob.substring(3, 13);
                        if (mob.substring(0, 1).contains("0")) {
                            mob= mob.substring(1, 11);
                        if (mob.contains("+")) {
                            mob= mob.replace("+", "");
                        mob= mob.substring(0, 10);
                        Log.i("mob", mob);


Is there a performance difference between i++ and ++i in C?

@Mark Even though the compiler is allowed to optimize away the (stack based) temporary copy of the variable and gcc (in recent versions) is doing so, doesn't mean all compilers will always do so.

I just tested it with the compilers we use in our current project and 3 out of 4 do not optimize it.

Never assume the compiler gets it right, especially if the possibly faster, but never slower code is as easy to read.

If you don't have a really stupid implementation of one of the operators in your code:

Alwas prefer ++i over i++.

Bootstrap full-width text-input within inline-form

have a look at something like this:

<form role="form">  
    <div class="row">
      <div class="col-xs-12">
        <div class="input-group input-group-lg">
            <input type="text" class="form-control" />
          <div class="input-group-btn">
            <button type="submit" class="btn">Search</button>
          </div><!-- /btn-group -->
        </div><!-- /input-group -->
      </div><!-- /.col-xs-12 -->
    </div><!-- /.row -->

pandas resample documentation

B         business day frequency
C         custom business day frequency (experimental)
D         calendar day frequency
W         weekly frequency
M         month end frequency
SM        semi-month end frequency (15th and end of month)
BM        business month end frequency
CBM       custom business month end frequency
MS        month start frequency
SMS       semi-month start frequency (1st and 15th)
BMS       business month start frequency
CBMS      custom business month start frequency
Q         quarter end frequency
BQ        business quarter endfrequency
QS        quarter start frequency
BQS       business quarter start frequency
A         year end frequency
BA, BY    business year end frequency
AS, YS    year start frequency
BAS, BYS  business year start frequency
BH        business hour frequency
H         hourly frequency
T, min    minutely frequency
S         secondly frequency
L, ms     milliseconds
U, us     microseconds
N         nanoseconds

See the timeseries documentation. It includes a list of offsets (and 'anchored' offsets), and a section about resampling.

Note that there isn't a list of all the different how options, because it can be any NumPy array function and any function that is available via groupby dispatching can be passed to how by name.

Is there a limit on an Excel worksheet's name length?

The file format would permit up to 255-character worksheet names, but if the Excel UI doesn't want you exceeding 31 characters, don't try to go beyond 31. App's full of weird undocumented limits and quirks, and feeding it files that are within spec but not within the range of things the testers would have tested usually causes REALLY strange behavior. (Personal favorite example: using the Excel 4.0 bytecode for an if() function, in a file with an Excel 97-style stringtable, disabled the toolbar button for bold in Excel 97.)

if else condition in blade file (laravel 5.3)

I think you are putting one too many curly brackets. Try this

            <td><a href="#" class="viewPopLink btn btn-default1" role="button" data-id="{!! $user->travel_id !!}" data-toggle="modal" data-target="#myModal">Approve/Reject</a> </td>
            <td>{!! $user->status !!}</td>

Best way to check if a character array is empty

Depends on whether or not your array is holding a null-terminated string. If so, then

if(text[0] == '\0') {}

should be sufficient.

Edit: Another method would be...

if (strcmp(text, "") == 0)

which is potentially less efficient but clearly expresses your intent.

Create a directly-executable cross-platform GUI app using Python

First you will need some GUI library with Python bindings and then (if you want) some program that will convert your python scripts into standalone executables.

Cross-platform GUI libraries with Python bindings (Windows, Linux, Mac)

Of course, there are many, but the most popular that I've seen in wild are:

Complete list is at

Single executable (all platforms)

  • PyInstaller - the most active(Could also be used with PyQt)
  • fbs - if you chose Qt above

Single executable (Windows)

  • py2exe - used to be the most popular

Single executable (Linux)

  • Freeze - works the same way like py2exe but targets Linux platform

Single executable (Mac)

  • py2app - again, works like py2exe but targets Mac OS

Insert line break in wrapped cell via code

Just do Ctrl + Enter inside the text box

Numpy: find index of the elements within range

a = np.array([1,2,3,4,5,6,7,8,9])
b = a[(a>2) & (a<8)]

The intel x86 emulator accelerator (HAXM installer) revision 6.0.5 is showing not compatible with windows

You likely have Hyper-V enabled. The manual installer provides this detailed notice when it refuses to install on a Windows with it on.

This computer does not support Intel Virtualization Technology (VT-x) or it is being exclusively used by Hyper-V. HAXM cannot be installed. Please ensure Hyper-V is disabled in Windows Features, or refer to the Intel HAXM documentation for more information.

How exactly does the python any() function work?

Simply saying, any() does this work : according to the condition even if it encounters one fulfilling value in the list, it returns true, else it returns false.

list = [2,-3,-4,5,6]

a = any(x>0 for x in lst)

print a:

list = [2,3,4,5,6,7]

a = any(x<0 for x in lst)

print a:

Delete directory with files in it?

Like Playnox's solution, but with the elegant built-in DirectoryIterator:

function delete_directory($dirPath){
  $objects=new DirectoryIterator($dirPath);
   foreach ($objects as $object){
   throw new Exception(__FUNCTION__.'(dirPath): dirPath is not a directory!');

Has an event handler already been added?

From outside the defining class, as @Telos mentions, you can only use EventHandler on the left-hand side of a += or a -=. So, if you have the ability to modify the defining class, you could provide a method to perform the check by checking if the event handler is null - if so, then no event handler has been added. If not, then maybe and you can loop through the values in Delegate.GetInvocationList. If one is equal to the delegate that you want to add as event handler, then you know it's there.

public bool IsEventHandlerRegistered(Delegate prospectiveHandler)
    if ( this.EventHandler != null )
        foreach ( Delegate existingHandler in this.EventHandler.GetInvocationList() )
            if ( existingHandler == prospectiveHandler )
                return true;
    return false;

And this could easily be modified to become "add the handler if it's not there". If you don't have access to the innards of the class that's exposing the event, you may need to explore -= and +=, as suggested by @Lou Franco.

However, you may be better off reexamining the way you're commissioning and decommissioning these objects, to see if you can't find a way to track this information yourself.

Add vertical scroll bar to panel

Assuming you're using winforms, default panel components does not offer you a way to disable the horizontal scrolling components. A workaround of this is to disable the auto scrolling and add a scrollbar yourself:

ScrollBar vScrollBar1 = new VScrollBar();
vScrollBar1.Dock = DockStyle.Right;
vScrollBar1.Scroll += (sender, e) => { panel1.VerticalScroll.Value = vScrollBar1.Value; };

Detailed discussion here.

How to call Makefile from another Makefile?

Instead of the -f of make you might want to use the -C <path> option. This first changes the to the path '<path>', and then calles make there.


  rm -f ./*~ ./gmon.out ./core $(SRC_DIR)/*~ $(OBJ_DIR)/*.o
  rm -f ../svn-commit.tmp~
  rm -f $(BIN_DIR)/$(PROJECT)
  $(MAKE) -C gtest-1.4.0/make clean

Get loop counter/index using for…of syntax in JavaScript

for…in iterates over property names, not values, and does so in an unspecified order (yes, even after ES6). You shouldn’t use it to iterate over arrays. For them, there’s ES5’s forEach method that passes both the value and the index to the function you give it:

var myArray = [123, 15, 187, 32];

myArray.forEach(function (value, i) {
    console.log('%d: %s', i, value);

// Outputs:
// 0: 123
// 1: 15
// 2: 187
// 3: 32

Or ES6’s Array.prototype.entries, which now has support across current browser versions:

for (const [i, value] of myArray.entries()) {
    console.log('%d: %s', i, value);

For iterables in general (where you would use a for…of loop rather than a for…in), there’s nothing built-in, however:

function* enumerate(iterable) {
    let i = 0;

    for (const x of iterable) {
        yield [i, x];

for (const [i, obj] of enumerate(myArray)) {
    console.log(i, obj);


If you actually did mean for…in – enumerating properties – you would need an additional counter. Object.keys(obj).forEach could work, but it only includes own properties; for…in includes enumerable properties anywhere on the prototype chain.

Attempt by security transparent method 'WebMatrix.WebData.PreApplicationStartCode.Start()'

You may also get :

Could not load file or assembly 'WebMatrix.Data, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

This has moved to this package

 Install-Package Microsoft.AspNet.WebPages.Data

You should probably do a clean build before attempting any of the answers to this question and after updating packages

Sending message through WhatsApp

Currently, the only official API that you may make a GET request to:

Anyways, there is a secret API program already being ran by WhatsApp

How does one target IE7 and IE8 with valid CSS?

For a more complete list as of 2015:

IE 6

* html .ie6 {property:value;}


.ie6 { _property:value;}

IE 7

*+html .ie7 {property:value;}


*:first-child+html .ie7 {property:value;}

IE 6 and 7

@media screen\9 {
    .ie67 {property:value;}


.ie67 { *property:value;}


.ie67 { #property:value;}

IE 6, 7 and 8

@media \0screen\,screen\9 {
    .ie678 {property:value;}

IE 8

html>/**/body .ie8 {property:value;}


@media \0screen {
    .ie8 {property:value;}

IE 8 Standards Mode Only

.ie8 { property /*\**/: value\9 }

IE 8,9 and 10

@media screen\0 {
    .ie8910 {property:value;}

IE 9 only

@media screen and (min-width:0) and (min-resolution: .001dpcm) { 
 // IE9 CSS

IE 9 and above

@media screen and (min-width:0) and (min-resolution: +72dpi) {
  // IE9+ CSS

IE 9 and 10

@media screen and (min-width:0) {

IE 10 only

_:-ms-lang(x), .ie10 { property:value\9; }

IE 10 and above

_:-ms-lang(x), .ie10up { property:value; }


@media all and (-ms-high-contrast: none), (-ms-high-contrast: active) {

IE 11 (and above..)

_:-ms-fullscreen, :root .ie11up { property:value; }

Javascript alternatives


Modernizr runs quickly on page load to detect features; it then creates a JavaScript object with the results, and adds classes to the html element

User agent selection

The Javascript:

var b = document.documentElement;
        b.setAttribute('data-useragent',  navigator.userAgent);
        b.setAttribute('data-platform', navigator.platform );
        b.className += ((!!('ontouchstart' in window) || !!('onmsgesturechange' in window))?' touch':'');

Adds (e.g) the below to the html element:

data-useragent='Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C)'

Allowing very targetted CSS selectors, e.g.:

html[data-useragent*='Chrome/13.0'] .nav{
    background:url(img/radial_grad.png) center bottom no-repeat;


If possible, avoid browser targeting. Identify and fix any issue(s) you identify. Support progressive enhancement and graceful degradation. With that in mind, this is an 'ideal world' scenario not always obtainable in a production environment, as such- the above should help provide some good options.

Attribution / Essential Reading

Importing Excel files into R, xlsx or xls

I would definitely try the read.xls function in the gdata package, which is considerably more mature than the xlsx package. It may require Perl ...

How do I validate a date in rails?

Here's a non-chronic answer..

class Pimping < ActiveRecord::Base

validate :valid_date?

def valid_date?
  if scheduled_on.present?
    unless scheduled_on.is_a?(Time)
      errors.add(:scheduled_on, "Is an invalid date.")

Is calling destructor manually always a sign of bad design?

I found 3 occasions where I needed to do this:

  • allocating/deallocating objects in memory created by memory-mapped-io or shared memory
  • when implementing a given C interface using C++ (yes this still happens today unfortunately (because I don't have enough clout to change it))
  • when implementing allocator classes

How to pip or easy_install tkinter on Windows

Had the same problem in Linux. This solved it. (I'm on Debian 9 derived Bunsen Helium)

$ sudo apt-get install python3-tk

How to convert current date into string in java?

For time as YYYY-MM-dd

String time = new DateTime( yourData ).toString("yyyy-MM-dd");

And the Library of DateTime is:

import org.joda.time.DateTime;

create table with sequence.nextval in oracle

In Oracle 12c, you can now specify the CURRVAL and NEXTVAL sequence pseudocolumns as default values for a column. Alternatively, you can use Identity columns; see:


  id          NUMBER DEFAULT t1_seq.NEXTVAL,
  description VARCHAR2(30)

Confused about stdin, stdout and stderr?

It would be more correct to say that stdin, stdout, and stderr are "I/O streams" rather than files. As you've noticed, these entities do not live in the filesystem. But the Unix philosophy, as far as I/O is concerned, is "everything is a file". In practice, that really means that you can use the same library functions and interfaces (printf, scanf, read, write, select, etc.) without worrying about whether the I/O stream is connected to a keyboard, a disk file, a socket, a pipe, or some other I/O abstraction.

Most programs need to read input, write output, and log errors, so stdin, stdout, and stderr are predefined for you, as a programming convenience. This is only a convention, and is not enforced by the operating system.

Cron job every three days

I am not a cron specialist, but how about:

0 */72 * * *

It will run every 72 hours non-interrupted.

join list of lists in python

If you're only going one level deep, a nested comprehension will also work:

>>> x = [["a","b"], ["c"]]
>>> [inner
...     for outer in x
...         for inner in outer]
['a', 'b', 'c']

On one line, that becomes:

>>> [j for i in x for j in i]
['a', 'b', 'c']

Convert string to date in bash

This worked for me :

date -d '20121212 7 days'
date -d '12-DEC-2012 7 days'
date -d '2012-12-12 7 days'
date -d '2012-12-12 4:10:10PM 7 days'
date -d '2012-12-12 16:10:55 7 days'

then you can format output adding parameter '+%Y%m%d'

How to acces external json file objects in vue.js app

If your file looks like this:

        "firstname": "toto",
        "lastname": "titi"
        "firstname": "toto2",
        "lastname": "titi2"

You can do:

import json from './json/data.json';
// ....
json.forEach(x => { console.log(x.firstname, x.lastname); });

how to update spyder on anaconda

Go to Anaconda Naviagator, find spyder,click settings in the top right corner of the spyder update tab

Remove querystring from URL

If using backbone.js (which contains url anchor as route), url query string may appear:

  1. before url anchor:

    var url = '';
  2. after url anchor:

    var url = '';


window.location.href.replace(, '');
// run as: ''.replace('?a=1&b=3', '');

Compiler error "archive for required library could not be read" - Spring Tool Suite

I deleted the local maven repository. Then just rightclick the project -> Maven -> Update Project... Select all concerned projects and click OK.

I get "Http failure response for (unknown url): 0 Unknown Error" instead of actual error message in Angular

For me it was a browser issue, since my requests were working fine in Postman.

Turns out that for some reason, Firefox and Chrome blocked requests going to port 6000, once I changed the ASP.NET API port to 4000, the error changed to a known CORS error which I could fix.

Chrome at least showed me ERR_UNSAFE_PORT which gave me a clue about what could be wrong.

AngularJs: How to set radio button checked based on model

Use ng-value instead of value.


Version with ng-checked is worse because of the code duplication.

SQL Query to fetch data from the last 30 days?

Try this : Using this you can select data from last 30 days

    purchase_date > DATE_SUB(CURDATE(), INTERVAL 1 MONTH)

RegEx to extract all matches from string using RegExp.exec

We are finally beginning to see a built-in matchAll function, see here for the description and compatibility table. It looks like as of May 2020, Chrome, Edge, Firefox, and Node.js (12+) are supported but not IE, Safari, and Opera. Seems like it was drafted in December 2018 so give it some time to reach all browsers, but I trust it will get there.

The built-in matchAll function is nice because it returns an iterable. It also returns capturing groups for every match! So you can do things like

// get the letters before and after "o"
let matches = "stackoverflow".matchAll(/(\w)o(\w)/g);

for (match of matches) {
    console.log("letter before:" + match[1]);
    console.log("letter after:" + match[2]);

arrayOfAllMatches = [...matches]; // you can also turn the iterable into an array

It also seem like every match object uses the same format as match(). So each object is an array of the match and capturing groups, along with three additional properties index, input, and groups. So it looks like:

[<match>, <group1>, <group2>, ..., index: <match offset>, input: <original string>, groups: <named capture groups>]

For more information about matchAll there is also a Google developers page. There are also polyfills/shims available.

Making a flex item float right

You can't use float inside flex container and the reason is that float property does not apply to flex-level boxes as you can see here Fiddle.

So if you want to position child element to right of parent element you can use margin-left: auto but now child element will also push other div to the right as you can see here Fiddle.

What you can do now is change order of elements and set order: 2 on child element so it doesn't affect second div

.parent {_x000D_
  display: flex;_x000D_
.child {_x000D_
  margin-left: auto;_x000D_
  order: 2;_x000D_
<div class="parent">_x000D_
  <div class="child">Ignore parent?</div>_x000D_
  <div>another child</div>_x000D_

Darkening an image with CSS (In any shape)

I would make a new image of the dog's silhouette (black) and the rest the same as the original image. In the html, add a wrapper div with this silhouette as as background. Now, make the original image semi-transparent. The dog will become darker and the background of the dog will stay the same. You can do :hover tricks by setting the opacity of the original image to 100% on hover. Then the dog pops out when you mouse over him!



<div class="wrapper">
  <div class="img">
    <img src="original.png">

How to return rows from left table not found in right table?

If you are asking for T-SQL then lets look at fundamentals first. There are three types of joins here each with its own set of logical processing phases as:

  1. A cross join is simplest of all. It implements only one logical query processing phase, a Cartesian Product. This phase operates on the two tables provided as inputs to the join and produces a Cartesian product of the two. That is, each row from one input is matched with all rows from the other. So if you have m rows in one table and n rows in the other, you get m×n rows in the result.
  2. Then are Inner joins : They apply two logical query processing phases: A Cartesian product between the two input tables as in a cross join, and then it filters rows based on a predicate that you specify in ON clause (also known as Join condition).
  3. Next comes the third type of joins, Outer Joins:

    In an outer join, you mark a table as a preserved table by using the keywords LEFT OUTER JOIN, RIGHT OUTER JOIN, or FULL OUTER JOIN between the table names. The OUTER keyword is optional. The LEFT keyword means that the rows of the left table are preserved; the RIGHT keyword means that the rows in the right table are preserved; and the FULL keyword means that the rows in both the left and right tables are preserved.

    The third logical query processing phase of an outer join identifies the rows from the preserved table that did not find matches in the other table based on the ON predicate. This phase adds those rows to the result table produced by the first two phases of the join, and uses NULL marks as placeholders for the attributes from the nonpreserved side of the join in those outer rows.

Now if we look at the question: To return records from the left table which are not found in the right table use Left outer join and filter out the rows with NULL values for the attributes from the right side of the join.

this in equals method

You are comparing two objects for equality. The snippet:

if (obj == this) {     return true; } 

is a quick test that can be read

"If the object I'm comparing myself to is me, return true"

. You usually see this happen in equals methods so they can exit early and avoid other costly comparisons.

Thymeleaf using path variables to th:href

Your code looks syntactically correct, but I think your property doesn't exist to create the URL.

I just tested it, and it works fine for me.

Try using category.idCategory instead of, for example…

  <tr th:each="category : ${categories}">
    <td th:text="${category.idCategory}"></td>
    <td th:text="${}"></td>
      <a th:href="@{'/category/edit/' + ${category.idCategory}}">view</a>

Array[n] vs Array[10] - Initializing array with variable vs real number

In C++, variable length arrays are not legal. G++ allows this as an "extension" (because C allows it), so in G++ (without being -pedantic about following the C++ standard), you can do:

int n = 10;
double a[n]; // Legal in g++ (with extensions), illegal in proper C++

If you want a "variable length array" (better called a "dynamically sized array" in C++, since proper variable length arrays aren't allowed), you either have to dynamically allocate memory yourself:

int n = 10;
double* a = new double[n]; // Don't forget to delete [] a; when you're done!

Or, better yet, use a standard container:

int n = 10;
std::vector<double> a(n); // Don't forget to #include <vector>

If you still want a proper array, you can use a constant, not a variable, when creating it:

const int n = 10;
double a[n]; // now valid, since n isn't a variable (it's a compile time constant)

Similarly, if you want to get the size from a function in C++11, you can use a constexpr:

constexpr int n()
    return 10;

double a[n()]; // n() is a compile time constant expression

ResourceDictionary in a separate assembly

Check out the pack URI syntax. You want something like this:

<ResourceDictionary Source="pack://application:,,,/YourAssembly;component/Subfolder/YourResourceFile.xaml"/>

How can I determine if a .NET assembly was built for x86 or x64?

An alternative to already mentioned tools is Telerik JustDecompile (free tool) which will display the information next to the assembly name:

Any or x86 or x64 information in Telerik

How to multiply individual elements of a list with a number?

If you use numpy.multiply

S = [22, 33, 45.6, 21.6, 51.8]
P = 2.45
multiply(S, P)

It gives you as a result

array([53.9 , 80.85, 111.72, 52.92, 126.91])

How to set recurring schedule for xlsm file using Windows Task Scheduler

I referred a blog by Kim for doing this and its working fine for me. See the blog

The automated execution of macro can be accomplished with the help of a VB Script file which is being invoked by Windows Task Scheduler at specified times.

Remember to replace 'YourWorkbook' with the name of the workbook you want to open and replace 'YourMacro' with the name of the macro you want to run.

See the VB Script File (just named it RunExcel.VBS):

    ' Create a WshShell to get the current directory
Dim WshShell
Set WshShell = CreateObject("WScript.Shell")

' Create an Excel instance
Dim myExcelWorker
Set myExcelWorker = CreateObject("Excel.Application") 

' Disable Excel UI elements
myExcelWorker.DisplayAlerts = False
myExcelWorker.AskToUpdateLinks = False
myExcelWorker.AlertBeforeOverwriting = False
myExcelWorker.FeatureInstall = msoFeatureInstallNone

' Tell Excel what the current working directory is 
' (otherwise it can't find the files)
Dim strSaveDefaultPath
Dim strPath
strSaveDefaultPath = myExcelWorker.DefaultFilePath
strPath = WshShell.CurrentDirectory
myExcelWorker.DefaultFilePath = strPath

' Open the Workbook specified on the command-line 
Dim oWorkBook
Dim strWorkerWB
strWorkerWB = strPath & "\YourWorkbook.xls"

Set oWorkBook = myExcelWorker.Workbooks.Open(strWorkerWB)

' Build the macro name with the full path to the workbook
Dim strMacroName
strMacroName = "'" & strPath & "\YourWorkbook" & "!Sheet1.YourMacro"
on error resume next 
   ' Run the calculation macro
   myExcelWorker.Run strMacroName
   if err.number <> 0 Then
      ' Error occurred - just close it down.
   End If
on error goto 0 


myExcelWorker.DefaultFilePath = strSaveDefaultPath

' Clean up and shut down
Set oWorkBook = Nothing

' Don’t Quit() Excel if there are other Excel instances 
' running, Quit() will shut those down also
if myExcelWorker.Workbooks.Count = 0 Then
End If

Set myExcelWorker = Nothing
Set WshShell = Nothing

You can test this VB Script from command prompt:

>> cscript.exe RunExcel.VBS

Once you have the VB Script file and workbook tested so that it does what you want, you can then use Microsoft Task Scheduler (Control Panel-> Administrative Tools--> Task Scheduler) to execute ‘cscript.exe RunExcel.vbs’ automatically for you.

Please note the path of the macro should be in correct format and inside single quotes like:

strMacroName = "'" & strPath & "\YourWorkBook.xlsm'" & 

Convert Bitmap to File

Try this:

bitmap.compress(Bitmap.CompressFormat.PNG, quality, outStream);

See this

Can anyone explain IEnumerable and IEnumerator to me?

A Minor contribution.

As many of them explain about 'when to use' and 'use with foreach'. I thought of adding Another States Difference here as requested in question about the difference between both IEnumerable an IEnumerator.

I created the below code sample based on the below discussion threads.

IEnumerable , IEnumerator vs foreach, when to use what What is the difference between IEnumerator and IEnumerable?

Enumerator preserves the state (iteration position) between function calls while iterations the other hand Enumerable does not.

Here is the tested example with comments to understand.

Experts please add/correct me.

static void EnumerableVsEnumeratorStateTest()
    IList<int> numList = new List<int>();


    Console.WriteLine("Using Enumerator - Remembers the state");

    Console.WriteLine("Using Enumerable - Does not Remembers the state");

    Console.WriteLine("Using Enumerable - 2nd functions start from the item 1 in the collection");

static void IterateFrom1to3(IEnumerator<int> numColl)
    while (numColl.MoveNext())

        if (numColl.Current > 3)
            // This method called 3 times for 3 items (4,5,6) in the collection. 
            // It remembers the state and displays the continued values.

static void IterateFrom3to6(IEnumerator<int> numColl)
    while (numColl.MoveNext())

static void IterateFrom1to3Eb(IEnumerable<int> numColl)
    foreach (int num in numColl)

        if (num>= 5)
            // The below method invokes for the last 2 items.
            //Since it doesnot persists the state it will displays entire collection 2 times.

static void IterateFrom3to6Eb(IEnumerable<int> numColl)
    foreach (int num in numColl)

Using lodash to compare jagged arrays (items existence without order)

There are already answers here, but here's my pure JS implementation. I'm not sure if it's optimal, but it sure is transparent, readable, and simple.

// Does array a contain elements of array b?
const contains = (a, b) => new Set([...a, ...b]).size === a.length
const isEqualSet = (a, b) => contains(a, b) && contains(b, a)

The rationale in contains() is that if a does contain all the elements of b, then putting them into the same set would not change the size.

For example, if const a = [1,2,3,4] and const b = [1,2], then new Set([...a, ...b]) === {1,2,3,4}. As you can see, the resulting set has the same elements as a.

From there, to make it more concise, we can boil it down to the following:

const isEqualSet = (a, b) => {
  const unionSize = new Set([...a, ...b])
  return unionSize === a.length && unionSize === b.length

How to remove gaps between subplots in matplotlib?

Another method is to use the pad keyword from plt.subplots_adjust(), which also accepts negative values:

import matplotlib.pyplot as plt

ax = [plt.subplot(2,2,i+1) for i in range(4)]

for a in ax:


Additionally, to remove the white at the outer fringe of all subplots (i.e. the canvas), always save with plt.savefig(fname, bbox_inches="tight").

How to redirect siteA to siteB with A or CNAME records

Try changing it to "subdomain ->"

The CNAME is an alias for a certain domain, so when you go to the control panel for, you shouldn't have to enter the whole name into the CNAME alias.

As far as the error you are getting, can you log onto and check the logs?

Where to place JavaScript in an HTML file?

Like others have said, it should most likely go in an external file. I prefer to include such files at the end of the <head />. This method is more human friendly than machine friendly, but that way I always know where the JS is. It is just not as readable to include script files anywhere else (imho).

I you really need to squeeze out every last ms then you probably should do what Yahoo says.

how can I enable PHP Extension intl?

I was having same kind of problem with ldap, intl, curl php extensions. I've solved those issues by the following ways:

At first you've to check whether these extensions have been enabled in the php.ini file by removing semicolon (;) in front of the following lines:


Secondly, libeay32.dll, ibssh2.dll and ssleay32.dll files have to be loaded by php properly to function those extensions properly. These dll files are required by several php extensions (ie curl, ldap, intl etc). These files generally reside in the php installation directory [for my case it is C:\php directory]. Additionally, for intl extension to be enabled you're gonna need some other dll files to be loaded by php properly. The name of these files begin with icu (ie icudt57.dll icuin57.dll etc for php version 5.6). You'll also find these files in the php main installation directory.

There is a alternate way you can load these files from your httpd.conf (apache configuratio file) file instead of copying them to the apache's bin directory. This can be done by using the following technique:

Please note that my php version is 5.5.

LoadFile  "C:/php/icudt51.dll"
LoadFile  "C:/php/icuin51.dll"
LoadFile  "C:/php/icuio51.dll"
LoadFile  "C:/php/icule51.dll"
LoadFile  "C:/php/iculx51.dll"
LoadFile  "C:/php/icutest51.dll"
LoadFile  "C:/php/icutu51.dll"
LoadFile  "C:/php/icuuc51.dll"

LoadFile  "C:/php/libeay32.dll"
LoadFile  "C:/php/libssh2.dll"
LoadFile  "C:/php/ssleay32.dll"

 That's it.

How to go back to previous page if back button is pressed in WebView?

You can try this for webview in a fragment:

private lateinit var webView: WebView

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    val root = inflater.inflate(R.layout.fragment_name, container, false)
    webView = root!!.findViewById(
    var url: String = ""
    webView.settings.javaScriptEnabled = true
    webView.webViewClient = WebViewClient()
    webView.setOnKeyListener{ v, keyCode, event ->
        if(keyCode == KeyEvent.KEYCODE_BACK && event.action == MotionEvent.ACTION_UP
            && webView.canGoBack()){
            return@setOnKeyListener true
    return root

How to divide two columns?

Presumably, those columns are integer columns - which will be the reason as the result of the calculation will be of the same type.

e.g. if you do this:

SELECT 1 / 2

you will get 0, which is obviously not the real answer. So, convert the values to e.g. decimal and do the calculation based on that datatype instead.



gives 0.500000

jQuery .ajax() POST Request throws 405 (Method Not Allowed) on RESTful WCF

Your code is actually attempting to make a Cross-domain (CORS) request, not an ordinary POST.

That is: Modern browsers will only allow Ajax calls to services in the same domain as the HTML page.

Example: A page in can only directly request services that are in, like If the service is in other domain, the browser won't make the direct call (as you'd expect). Instead, it will try to make a CORS request.

To put it shortly, to perform a CORS request, your browser:

  • Will first send an OPTION request to the target URL
  • And then only if the server response to that OPTION contains the adequate headers (Access-Control-Allow-Origin is one of them) to allow the CORS request, the browse will perform the call (almost exactly the way it would if the HTML page was at the same domain).
    • If the expected headers don't come, the browser simply gives up (like it did to you).

How to solve it? The simplest way is to enable CORS (enable the necessary headers) on the server.

If you don't have server-side access to it, you can mirror the web service from somewhere else, and then enable CORS there.

How to insert a large block of HTML in JavaScript?

If I understand correctly, you're looking for a multi-line representation, for readability? You want something like a here-string in other languages. Javascript can come close with this:

var x =
    "<div> \
    <span> \
    <p> \
    some text \
    </p> \

What is the difference between '/' and '//' when used for division?

Python 2.x Clarification:

To clarify for the Python 2.x line, / is neither floor division nor true division.

/ is floor division when both args are int, but is true division when either of the args are float.

How to get the request parameters in Symfony 2?

Your options:

  1. Simple:
    • $request->request->get('param') ($_POST['param']) or
    • $request->query->get('param') ($_GET['param'])
  2. Good Symfony forms with all validation, value transormation and form rendering with errors and many other features:
  3. Something in between (see example below)
 * @Route("/customers", name="customers")
 * @param Request $request
 * @return Response
public function index(Request $request)
    $optionsResolver = new OptionsResolver();
        'email' => '',
        'phone' => '',
    $filter = $optionsResolver->resolve($request->query->all());

    /** @var CustomerRepository $customerRepository */
    $customerRepository = $this->getDoctrine()->getRepository('AppBundle:Customer');

    /** @var Customer[] $customers */
    $customers = $customerRepository->findFilteredCustomers($filter);

    return $this->render(':customers:index.html.twig', [
        'customers' => $customers,
        'filter' => $filter,

More about OptionsResolver -

find_spec_for_exe': can't find gem bundler (>= 0.a) (Gem::GemNotFoundException)

If you changed the ruby version you're using with rvm use, remove Gemfile.lock and try again.

How do the likely/unlikely macros in the Linux kernel work and what is their benefit?

These are GCC functions for the programmer to give a hint to the compiler about what the most likely branch condition will be in a given expression. This allows the compiler to build the branch instructions so that the most common case takes the fewest number of instructions to execute.

How the branch instructions are built are dependent upon the processor architecture.

POST unchecked HTML checkboxes

The solution I liked the most so far is to put a hidden input with the same name as the checkbox that might not be checked. I think it works so that if the checkbox isn't checked, the hidden input is still successful and sent to the server but if the checkbox is checked it will override the hidden input before it. This way you don't have to keep track of which values in the posted data were expected to come from checkboxes.

  <input type='hidden' value='0' name='selfdestruct'>
  <input type='checkbox' value='1' name='selfdestruct'>

How to use UIPanGestureRecognizer to move object? iPhone/iPad

The Swift 2 version:

// start detecting pan gesture
let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(TTAltimeterDetailViewController.panGestureDetected(_:)))
panGestureRecognizer.minimumNumberOfTouches = 1

func panGestureDetected(panGestureRecognizer: UIPanGestureRecognizer) {
    print("pan gesture recognized")