Programs & Examples On #Dynamic reports

DynamicReports allows to create dynamic report designs. You can very quickly create reports and produce documents that can be displayed, printed or exported into many popular formats such as PDF, Excel, Word and others.

When to use React "componentDidUpdate" method?

When something in the state has changed and you need to call a side effect (like a request to api - get, put, post, delete). So you need to call componentDidUpdate() because componentDidMount() is already called.

After calling side effect in componentDidUpdate(), you can set the state to new value based on the response data in the then((response) => this.setState({newValue: "here"})). Please make sure that you need to check prevProps or prevState to avoid infinite loop because when setting state to a new value, the componentDidUpdate() will call again.

There are 2 places to call a side effect for best practice - componentDidMount() and componentDidUpdate()

How to use su command over adb shell?

The su command does not execute anything, it just raise your privileges.

Try adb shell su -c YOUR_COMMAND.

ValidateAntiForgeryToken purpose, explanation and example

Microsoft provides us built-in functionality which we use in our application for security purposes, so no one can hack our site or invade some critical information.

From Purpose Of ValidateAntiForgeryToken In MVC Application by Harpreet Singh:

Use of ValidateAntiForgeryToken

Let’s try with a simple example to understand this concept. I do not want to make it too complicated, that’s why I am going to use a template of an MVC application, already available in Visual Studio. We will do this step by step. Let’s start.

  1. Step 1 - Create two MVC applications with default internet template and give those names as CrossSite_RequestForgery and Attack_Application respectively.

  2. Now, open CrossSite_RequestForgery application's Web Config and change the connection string with the one given below and then save.


<connectionStrings> <add name="DefaultConnection" connectionString="Data Source=local\SQLEXPRESS;Initial Catalog=CSRF;
Integrated Security=true;" providerName="System.Data.SqlClient" /> 
  1. Now, click on Tools >> NuGet Package Manager, then Package Manager Console

  2. Now, run the below mentioned three commands in Package Manager Console to create the database.

Enable-Migrations add-migration first update-database

Important Notes - I have created database with code first approach because I want to make this example in the way developers work. You can create database manually also. It's your choice.

  1. Now, open Account Controller. Here, you will see a register method whose type is post. Above this method, there should be an attribute available as [ValidateAntiForgeryToken]. Comment this attribute. Now, right click on register and click go to View. There again, you will find an html helper as @Html.AntiForgeryToken() . Comment this one also. Run the application and click on register button. The URL will be open as:


Notes- I know now the question being raised in all readers’ minds is why these two helpers need to be commented, as everyone knows these are used to validate request. Then, I just want to let you all know that this is just because I want to show the difference after and before applying these helpers.

  1. Now, open the second application which is Attack_Application. Then, open Register method of Account Controller. Just change the POST method with the simple one, shown below.

    Registration Form
    1. @Html.LabelFor(m => m.UserName) @Html.TextBoxFor(m => m.UserName)
    2. @Html.LabelFor(m => m.Password) @Html.PasswordFor(m => m.Password)
    3. @Html.LabelFor(m => m.ConfirmPassword) @Html.PasswordFor(m => m.ConfirmPassword)

7.Now, suppose you are a hacker and you know the URL from where you can register user in CrossSite_RequestForgery application. Now, you created a Forgery site as Attacker_Application and just put the same URL in post method.

8.Run this application now and fill the register fields and click on register. You will see you are registered in CrossSite_RequestForgery application. If you check the database of CrossSite_RequestForgery application then you will see and entry you have entered.

  1. Important - Now, open CrossSite_RequestForgery application and comment out the token in Account Controller and register the View. Try to register again with the same process. Then, an error will occur as below.

Server Error in '/' Application. ________________________________________ The required anti-forgery cookie "__RequestVerificationToken" is not present.

This is what the concept says. What we add in View i.e. @Html.AntiForgeryToken() generates __RequestVerificationToken on load time and [ValidateAntiForgeryToken] available on Controller method. Match this token on post time. If token is the same, then it means this is a valid request.

Scala check if element is present in a list

this should work also with different predicate

myFunction(strings.find( _ == mystring ).isDefined)

GROUP BY to combine/concat a column

A good question. Should tell you it took some time to crack this one. Here is my result.


VALUES  (1, 'Me', 'act1', 'ab'),
        (2, 'Me', 'act1', 'cd'),
        (3, 'You', 'act2', 'xy'),
        (4, 'You', 'act2', 'st')

        SELECT ',' + T2.PAGEURL  
        FROM @TABLE T2  
        WHERE T1.USERS = T2.USERS  
        FOR XML PATH ('')  

Export a graph to .eps file with R

Yes, open a postscript() device with a filename ending in .eps, do your plot(s) and call

Difference between return 1, return 0, return -1 and exit?

return in function return execution back to caller and exit from function terminates the program.

in main function return 0 or exit(0) are same but if you write exit(0) in different function then you program will exit from that position.

returning different values like return 1 or return -1 means that program is returning error .

When exit(0) is used to exit from program, destructors for locally scoped non-static objects are not called. But destructors are called if return 0 is used.

R - test if first occurrence of string1 is followed by string2

I think it's worth answering the generic question "R - test if string contains string" here.

For that, use the grep function.

# example:
> if(length(grep("ab","aacd"))>0) print("found") else print("Not found")
[1] "Not found"
> if(length(grep("ab","abcd"))>0) print("found") else print("Not found")
[1] "found"

How to convert latitude or longitude to meters?

One nautical mile (1852 meters) is defined as one arcminute of longitude at the equator. However, you need to define a map projection (see also UTM) in which you are working for the conversion to really make sense.

Associating enums with strings in C#

C# doesn't support enumerated strings, but for most situations you can use a List or Dictionary to get the desired effect.

E.g. To print pass/fail results:

List<string> PassFail = new List<string> { "FAIL", "PASS" };
bool result = true;
Console.WriteLine("Test1: " + PassFail[result.GetHashCode()]);

PHP: If internet explorer 6, 7, 8 , or 9

I do this


$isIE7  = (bool)preg_match('/msie 7./i', $u );
$isIE8  = (bool)preg_match('/msie 8./i', $u );
$isIE9  = (bool)preg_match('/msie 9./i', $u );
$isIE10 = (bool)preg_match('/msie 10./i', $u );

if ($isIE9) {
    //do ie9 stuff

Generate class from database table

slightly modified from top reply:

declare @TableName sysname = 'HistoricCommand'

declare @Result varchar(max) = '[System.Data.Linq.Mapping.Table(Name = "' + @TableName + '")]
public class Dbo' + @TableName + '

select @Result = @Result + '
    [System.Data.Linq.Mapping.Column(Name = "' + t.ColumnName + '", IsPrimaryKey = ' + pkk.ISPK + ')]
    public ' + ColumnType + NullableSign + ' ' + t.ColumnName + ' { get; set; }
        replace(, ' ', '_') ColumnName,
        column_id ColumnId,
            when 'bigint' then 'long'
            when 'binary' then 'byte[]'
            when 'bit' then 'bool'
            when 'char' then 'string'
            when 'date' then 'DateTime'
            when 'datetime' then 'DateTime'
            when 'datetime2' then 'DateTime'
            when 'datetimeoffset' then 'DateTimeOffset'
            when 'decimal' then 'decimal'
            when 'float' then 'float'
            when 'image' then 'byte[]'
            when 'int' then 'int'
            when 'money' then 'decimal'
            when 'nchar' then 'string'
            when 'ntext' then 'string'
            when 'numeric' then 'decimal'
            when 'nvarchar' then 'string'
            when 'real' then 'double'
            when 'smalldatetime' then 'DateTime'
            when 'smallint' then 'short'
            when 'smallmoney' then 'decimal'
            when 'text' then 'string'
            when 'time' then 'TimeSpan'
            when 'timestamp' then 'DateTime'
            when 'tinyint' then 'byte'
            when 'uniqueidentifier' then 'Guid'
            when 'varbinary' then 'byte[]'
            when 'varchar' then 'string'
            else 'UNKNOWN_' +
        end ColumnType,
            when col.is_nullable = 1 and in ('bigint', 'bit', 'date', 'datetime', 'datetime2', 'datetimeoffset', 'decimal', 'float', 'int', 'money', 'numeric', 'real', 'smalldatetime', 'smallint', 'smallmoney', 'time', 'tinyint', 'uniqueidentifier') 
            then '?' 
            else '' 
        end NullableSign
    from sys.columns col
        join sys.types typ on
            col.system_type_id = typ.system_type_id AND col.user_type_id = typ.user_type_id         
    where object_id = object_id(@TableName) 
) t, 
                SELECT  AS 'ColumnName', CASE WHEN IS NULL THEN 'false' ELSE 'true' END ISPK           
                FROM        sys.columns c
                    JOIN    sys.tables  t   ON c.object_id = t.object_id    
                    LEFT JOIN (SELECT   K.COLUMN_NAME , C.CONSTRAINT_TYPE as pk  
                        ON K.TABLE_NAME = C.TABLE_NAME
                            AND K.CONSTRAINT_NAME = C.CONSTRAINT_NAME
                            AND K.CONSTRAINT_SCHEMA = C.CONSTRAINT_SCHEMA            
                        WHERE K.TABLE_NAME = @TableName) as dd
                     ON dd.COLUMN_NAME =
                 WHERE = @TableName            
            ) pkk
where pkk.ColumnName = t.ColumnName
order by ColumnId

set @Result = @Result  + '

print @Result

which makes output needed for full LINQ in C# declaration

[System.Data.Linq.Mapping.Table(Name = "HistoricCommand")]
public class DboHistoricCommand
    [System.Data.Linq.Mapping.Column(Name = "HistoricCommandId", IsPrimaryKey = true)]
    public int HistoricCommandId { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "PHCloudSoftwareInstanceId", IsPrimaryKey = true)]
    public int PHCloudSoftwareInstanceId { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "CommandType", IsPrimaryKey = false)]
    public int CommandType { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "InitiatedDateTime", IsPrimaryKey = false)]
    public DateTime InitiatedDateTime { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "CompletedDateTime", IsPrimaryKey = false)]
    public DateTime CompletedDateTime { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "WasSuccessful", IsPrimaryKey = false)]
    public bool WasSuccessful { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "Message", IsPrimaryKey = false)]
    public string Message { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "ResponseData", IsPrimaryKey = false)]
    public string ResponseData { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "Message_orig", IsPrimaryKey = false)]
    public string Message_orig { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "Message_XX", IsPrimaryKey = false)]
    public string Message_XX { get; set; }


Sort a List of Object in VB.NET

you must implement IComparer interface.

In this sample I've my custom object JSONReturn, I implement my class like this :

Friend Class JSONReturnComparer
    Implements IComparer(of JSONReturn)

    Public Function Compare(x As JSONReturn, y As JSONReturn) As Integer Implements    IComparer(Of JSONReturn).Compare
        Return String.Compare(x.Name, y.Name)
    End Function

End Class

I call my sort List method like this : alResult.Sort(new JSONReturnComparer())

Maybe it could help you

Remove last character of a StringBuilder?

As of Java 8, the String class has a static method join. The first argument is a string that you want between each pair of strings, and the second is an Iterable<CharSequence> (which are both interfaces, so something like List<String> works. So you can just do this:

String.join(",", serverIds);

Also in Java 8, you could use the new StringJoiner class, for scenarios where you want to start constructing the string before you have the full list of elements to put in it.

how to check for null with a ng-if values in a view with angularjs?

Here is a simple example that I tried to explain.

    <div *ngIf="product">     <!--If "product" exists-->
      <h2>Product Details</h2><hr>
      <h4>Name: {{ }}</h4>
      <h5>Price: {{ product.price | currency }}</h5>
      <p> Description: {{ product.description }}</p>

    <div *ngIf="!product">     <!--If "product" not exists-->
       *Product not found

What's the purpose of the LEA instruction?

It seems that lots of answers already complete, I'd like to add one more example code for showing how the lea and move instruction work differently when they have the same expression format.

To make a long story short, lea instruction and mov instructions both can be used with the parentheses enclosing the src operand of the instructions. When they are enclosed with the (), the expression in the () is calculated in the same way; however, two instructions will interpret the calculated value in the src operand in a different way.

Whether the expression is used with the lea or mov, the src value is calculated as below.

D ( Rb, Ri, S ) => (Reg[Rb]+S*Reg[Ri]+ D)

However, when it is used with the mov instruction, it tries to access the value pointed to by the address generated by the above expression and store it to the destination.

In contrast of it, when the lea instruction is executed with the above expression, it loads the generated value as it is to the destination.

The below code executes the lea instruction and mov instruction with the same parameter. However, to catch the difference, I added a user-level signal handler to catch the segmentation fault caused by accessing a wrong address as a result of mov instruction.

Example code

#define _GNU_SOURCE 1  /* To pick up REG_RIP */
#include <stdio.h> 
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <signal.h>

register_handler (uint32_t event, void (*handler)(int, siginfo_t*, void*))
        uint32_t ret = 0;
        struct sigaction act;

        memset(&act, 0, sizeof(act));
        act.sa_sigaction = handler;
        act.sa_flags = SA_SIGINFO;
        ret = sigaction(event, &act, NULL);
        return ret;

segfault_handler (int signum, siginfo_t *info, void *priv)
        ucontext_t *context = (ucontext_t *)(priv);
        uint64_t rip = (uint64_t)(context->uc_mcontext.gregs[REG_RIP]);
        uint64_t faulty_addr = (uint64_t)(info->si_addr);

        printf("inst at 0x%lx tries to access memory at %ld, but failed\n",

        int result_of_lea = 0;

        register_handler(SIGSEGV, segfault_handler);

        //initialize registers %eax = 1, %ebx = 2

        // the compiler will emit something like
           // mov $1, %eax
           // mov $2, %ebx
        // because of the input operands
        asm("lea 4(%%rbx, %%rax, 8), %%edx \t\n"
            :"=d" (result_of_lea)   // output in EDX
            : "a"(1), "b"(2)        // inputs in EAX and EBX
            : // no clobbers

        //lea 4(rbx, rax, 8),%edx == lea (rbx + 8*rax + 4),%edx == lea(14),%edx
        printf("Result of lea instruction: %d\n", result_of_lea);

        asm volatile ("mov 4(%%rbx, %%rax, 8), %%edx"
                       : "a"(1), "b"(2)
                       : "edx"  // if it didn't segfault, it would write EDX

Execution result

Result of lea instruction: 14
inst at 0x4007b5 tries to access memory at 14, but failed

GIT vs. Perforce- Two VCS will enter... one will leave

Here's what I don't like about git:

First of all, I think the distributed idea flies in the face of reality. Everybody who's actually using git is doing so in a centralised way, even Linus Torvalds. If the kernel was managed in a distributed way, that would mean I couldn't actually download the "official" kernel sources - there wouldn't be one - I'd have to decide whether I want Linus' version, or Joe's version, or Bill's version. That would obviously be ridiculous, and that's why there is an official definition which Linus controls using a centralised workflow.

If you accept that you want a centralised definition of your stuff, then it becomes clear that the server and client roles are completely different, so the dogma that the client and server softwares should be the same becomes purely limiting. The dogma that the client and server data should be the same becomes patently ridiculous, especially in a codebase that's got fifteen years of history that nobody cares about but everybody would have to clone.

What we actually want to do with all that old stuff is bung it in a cupboard and forget that it's there, just like any normal VCS does. The fact that git hauls it all back and forth over the network every day is very dangerous, because it nags you to prune it. That pruning involves a lot of tedious decisions and it can go wrong. So people will probably keep a whole series of snapshot repos from various points in history, but wasn't that what source control was for in the first place? This problem didn't exist until somebody invented the distributed model.

Git actively encourages people to rewrite history, and the above is probably one reason for that. Every normal VCS makes rewriting history impossible for all but the admins, and makes sure the admins have no reason to consider it. Correct me if I'm wrong, but as far as I know, git provides no way to grant normal users write access but ban them from rewriting history. That means any developer with a grudge (or who was still struggling with the learning curve) could trash the whole codebase. How do we tighten that one? Well, either you make regular backups of the entire history, i.e. you keep history squared, or you ban write access to all except some poor sod who would receive all the diffs by email and merge them by hand.

Let's take an example of a well-funded, large project and see how git is working for them: Android. I once decided to have a play with the android system itself. I found out that I was supposed to use a bunch of scripts called repo to get at their git. Some of repo runs on the client and some on the server, but both, by their very existence, are illustrating the fact that git is incomplete in either capacity. What happened is that I was unable to pull the sources for about a week and then gave up altogether. I would have had to pull a truly vast amount of data from several different repositories, but the server was completely overloaded with people like me. Repo was timing out and was unable to resume from where it had timed out. If git is so distributable, you'd have thought that they'd have done some kind of peer-to-peer thing to relieve the load on that one server. Git is distributable, but it's not a server. Git+repo is a server, but repo is not distributable cos it's just an ad-hoc collection of hacks.

A similar illustration of git's inadequacy is gitolite (and its ancestor which apparently didn't work out so well.) Gitolite describes its job as easing the deployment of a git server. Again, the very existence of this thing proves that git is not a server, any more than it is a client. What's more, it never will be, because if it grew into either it would be betraying it's founding principles.

Even if you did believe in the distributed thing, git would still be a mess. What, for instance, is a branch? They say that you implicitly make a branch every time you clone a repository, but that can't be the same thing as a branch in a single repository. So that's at least two different things being referred to as branches. But then, you can also rewind in a repo and just start editing. Is that like the second type of branch, or something different again? Maybe it depends what type of repo you've got - oh yes - apparently the repo is not a very clear concept either. There are normal ones and bare ones. You can't push to a normal one because the bare part might get out of sync with its source tree. But you can't cvsimport to a bare one cos they didn't think of that. So you have to cvsimport to a normal one, clone that to a bare one which developers hit, and cvsexport that to a cvs working copy which still has to be checked into cvs. Who can be bothered? Where did all these complications come from? From the distributed idea itself. I ditched gitolite in the end because it was imposing even more of these restrictions on me.

Git says that branching should be light, but many companies already have a serious rogue branch problem so I'd have thought that branching should be a momentous decision with strict policing. This is where perforce really shines...

In perforce you rarely need branches because you can juggle changesets in a very agile way. For instance, the usual workflow is that you sync to the last known good version on mainline, then write your feature. Whenever you attempt to modify a file, the diff of that file gets added to your "default changeset". When you attempt to check in the changeset, it automatically tries to merge the news from mainline into your changeset (effectively rebasing it) and then commits. This workflow is enforced without you even needing to understand it. Mainline thus collects a history of changes which you can quite easily cherry pick your way through later. For instance, suppose you want to revert an old one, say, the one before the one before last. You sync to the moment before the offending change, mark the affected files as part of the changeset, sync to the moment after and merge with "always mine". (There was something very interesting there: syncing doesn't mean having the same thing - if a file is editable (i.e. in an active changeset) it won't be clobbered by the sync but marked as due for resolving.) Now you have a changelist that undoes the offending one. Merge in the subsequent news and you have a changelist that you can plop on top of mainline to have the desired effect. At no point did we rewrite any history.

Now, supposing half way through this process, somebody runs up to you and tells you to drop everything and fix some bug. You just give your default changelist a name (a number actually) then "suspend" it, fix the bug in the now empty default changelist, commit it, and resume the named changelist. It's typical to have several changelists suspended at a time where you try different things out. It's easy and private. You get what you really want from a branch regime without the temptation to procrastinate or chicken out of merging to mainline.

I suppose it would be theoretically possible to do something similar in git, but git makes practically anything possible rather than asserting a workflow we approve of. The centralised model is a bunch of valid simplifications relative to the distributed model which is an invalid generalisation. It's so overgeneralised that it basically expects you to implement source control on top of it, as repo does.

The other thing is replication. In git, anything is possible so you have to figure it out for yourself. In perforce, you get an effectively stateless cache. The only configuration it needs to know is where the master is, and the clients can point at either the master or the cache at their discretion. That's a five minute job and it can't go wrong.

You've also got triggers and customisable forms for asserting code reviews, bugzilla references etc, and of course, you have branches for when you actually need them. It's not clearcase, but it's close, and it's dead easy to set up and maintain.

All in all, I think that if you know you're going to work in a centralised way, which everybody does, you might as well use a tool that was designed with that in mind. Git is overrated because of Linus' fearsome wit together with peoples' tendency to follow each other around like sheep, but its main raison d'etre doesn't actually stand up to common sense, and by following it, git ties its own hands with the two huge dogmas that (a) the software and (b) the data have to be the same at both client and server, and that will always make it complicated and lame at the centralised job.

Move an array element from one array position to another

var ELEMS = ['a', 'b', 'c', 'd', 'e'];_x000D_
    Source item will remove and it will be placed just after destination_x000D_
function moveItemTo(sourceItem, destItem, elements) {_x000D_
    var sourceIndex = elements.indexOf(sourceItem);_x000D_
    var destIndex = elements.indexOf(destItem);_x000D_
    if (sourceIndex >= -1 && destIndex > -1) {_x000D_
        elements.splice(destIndex, 0, elements.splice(sourceIndex, 1)[0]);_x000D_
    return elements;_x000D_
console.log('Init: ', ELEMS);_x000D_
var result = moveItemTo('a', 'c', ELEMS);_x000D_
console.log('BeforeAfter: ', result);

Fill an array with random numbers

You can call the randomFill() method in a loop and fill your array in the main() method like this.

public static void main(String args[]) {
    for (int i = 0; i < anArray.length; i++) {
        anArray[i] = randomFill();

You would then need to use rand.nextDouble() in your randomFill() method the array to be filled is a double array. The below snippet should help you get random double values to be filled into your array.

double randomDoubleValue = rand.nextDouble();
return randomDoubleValue;

JSON encode MySQL results

we could simplify Paolo Bergantino answer like this

$sth = mysql_query("SELECT ...");
print json_encode(mysql_fetch_assoc($sth));

Add new element to an existing object

You are looking for the jQuery extend method. This will allow you to add other members to your already created JS object.

Why can't I define a default constructor for a struct in .NET?

You can make a static property that initializes and returns a default "rational" number:

public static Rational One => new Rational(0, 1); 

And use it like:

var rat = Rational.One;

In C#, what's the difference between \n and \r\n?

\n is the line break used by Unix(-like) systems, \r\n is used by windows. This has nothing to do with C#.

Multiple conditions in if statement shell script

if using /bin/sh you can use:

if [ <condition> ] && [ <condition> ]; then

if using /bin/bash you can use:

if [[ <condition> && <condition> ]]; then

Rmi connection refused with localhost

It seems to work when I replace the

Runtime.getRuntime().exec("rmiregistry 2020");



anyone an idea why? What's the difference?

Scp command syntax for copying a folder from local machine to a remote server

scp -r C:/site user@server_ip:path

path is the place, where site will be copied into the remote server

EDIT: As I said in my comment, try pscp, as you want to use scp using PuTTY.

The other option is WinSCP

port 8080 is already in use and no process using 8080 has been listed

PID is the process ID - not the port number. You need to look for an entry with ":8080" at the end of the address/port part (the second column). Then you can look at the PID and use Task Manager to work out which process is involved... or run netstat -abn which will show the process names (but must be run under an administrator account).

Having said that, I would expect the find "8080" to find it...

Another thing to do is just visit http://localhost:8080 - on that port, chances are it's a web server of some description.

VBA EXCEL Multiple Nested FOR Loops that Set two variable for expression

I can't get to your google docs file at the moment but there are some issues with your code that I will try to address while answering

Sub stituterangersNEW()
Dim t As Range
Dim x As Range
Dim dify As Boolean
Dim difx As Boolean
Dim time2 As Date
Dim time1 As Date

    'You said time1 doesn't change, so I left it in a singe cell.
    'If that is not correct, you will have to play with this some more.
    time1 = Range("A6").Value

    'Looping through each of our output cells.
    For Each t In Range("B7:E9") 'Change these to match your real ranges.

        'Looping through each departure date/time.
        '(Only one row in your example. This can be adjusted if needed.)
        For Each x In Range("B2:E2") 'Change these to match your real ranges.
            'Check to see if our dep time corresponds to
            'the matching column in our output
            If t.Column = x.Column Then
                'If it does, then check to see what our time value is
                If x > 0 Then
                    time2 = x.Value
                    'Apply the change to the output cell.
                    t.Value = time1 - time2
                    'Exit out of this loop and move to the next output cell.
                    Exit For
                End If
            End If
            'If the columns don't match, or the x value is not a time
            'then we'll move to the next dep time (x)
        Next x
    Next t

End Sub


I changed you worksheet to play with (see above for the new Sub). This probably does not suite your needs directly, but hopefully it will demonstrate the conept behind what I think you want to do. Please keep in mind that this code does not follow all the coding best preactices I would recommend (e.g. validating the time is actually a TIME and not some random other data type).

     A                      B                   C                   D                  E
1    LOAD_NUMBER            1                   2                   3                  4
2    DEPARTURE_TIME_DATE    11/12/2011 19:30    11/12/2011 19:30    11/12/2011 19:30    11/12/2011 20:00                
4    Dry_Refrig 7585.1  0   10099.8 16700
6    1/4/2012 19:30

Using the sub I got this output:

    A           B             C             D             E
7   Friday      1272:00:00    1272:00:00    1272:00:00    1271:30:00
8   Saturday    1272:00:00    1272:00:00    1272:00:00    1271:30:00
9   Thursday    1272:00:00    1272:00:00    1272:00:00    1271:30:00

Pandas convert string to int

You need add parameter errors='coerce' to function to_numeric:

ID = pd.to_numeric(ID, errors='coerce')

If ID is column:

df.ID = pd.to_numeric(df.ID, errors='coerce')

but non numeric are converted to NaN, so all values are float.

For int need convert NaN to some value e.g. 0 and then cast to int:

df.ID = pd.to_numeric(df.ID, errors='coerce').fillna(0).astype(np.int64)


df = pd.DataFrame({'ID':['4806105017087','4806105017087','CN414149']})
print (df)
0  4806105017087
1  4806105017087
2       CN414149

print (pd.to_numeric(df.ID, errors='coerce'))
0    4.806105e+12
1    4.806105e+12
2             NaN
Name: ID, dtype: float64

df.ID = pd.to_numeric(df.ID, errors='coerce').fillna(0).astype(np.int64)
print (df)
0  4806105017087
1  4806105017087
2              0

EDIT: If use pandas 0.25+ then is possible use integer_na:

df.ID = pd.to_numeric(df.ID, errors='coerce').astype('Int64')
print (df)
0  4806105017087
1  4806105017087
2            NaN

What is the optimal way to compare dates in Microsoft SQL server?

Get items when the date is between fromdate and toDate.

where convert(date, fromdate, 103 ) <= '2016-07-26' and convert(date, toDate, 103) >= '2016-07-26'

Using Composer's Autoload

Just create a symlink in your src folder for the namespace pointing to the folder containing your classes...

ln -s ../src/AppName ./src/AppName

Your autoload in composer will look the same...

"autoload": {
    "psr-0": {"AppName": "src/"}

And your AppName namespaced classes will start a directory up from your current working directory in a src folder now... that should work.

Select 50 items from list at random to write to file

If the list is in random order, you can just take the first 50.

Otherwise, use

import random
random.sample(the_list, 50)

random.sample help text:

sample(self, population, k) method of random.Random instance
    Chooses k unique random elements from a population sequence.

    Returns a new list containing elements from the population while
    leaving the original population unchanged.  The resulting list is
    in selection order so that all sub-slices will also be valid random
    samples.  This allows raffle winners (the sample) to be partitioned
    into grand prize and second place winners (the subslices).

    Members of the population need not be hashable or unique.  If the
    population contains repeats, then each occurrence is a possible
    selection in the sample.

    To choose a sample in a range of integers, use xrange as an argument.
    This is especially fast and space efficient for sampling from a
    large population:   sample(xrange(10000000), 60)

How do I dynamically set the selected option of a drop-down list using jQuery, JavaScript and HTML?

Your code works for me. When does addSalespersonOption get called? There may be a problem with that call.

Also some of your html is a bit off (maybe copy/paste problem?), but that didn't seem to cause any problems. Your select should look like this:

<select id="salesperson"> 
    <option value="">(select)</option> 

instead of this:

<select id="salesperson" /> 
    <option value"">(select)</option> 

Edit: When does your options list get dynamically populated? Are you sure you are passing 'on' for the defSales value in your call to addSalespersonOption? Try changing that code to this:

if (selected == "on") { 
    alert('setting default selected option to ' + text);
    html = '<option value="'+value+'" selected="selected">'+text+'</option>'; 

and see if the alert happens and what is says if it does happen.

Edit: Working example of my testing (the error:undefined is from jsbin, not my code).

Avoid line break between html elements

nobr is too unreliable, use tables

          <td> something </td>
          <td> something </td>

It all goes on the same line, everything is level with eachother, and you have much more freedom if you want to change something later.

How to globally replace a forward slash in a JavaScript string?

Is this what you want?

'string with / in it'.replace(/\//g, '\\');

Difference between / and /* in servlet mapping url pattern


The /* on a servlet overrides all other servlets, including all servlets provided by the servletcontainer such as the default servlet and the JSP servlet. Whatever request you fire, it will end up in that servlet. This is thus a bad URL pattern for servlets. Usually, you'd like to use /* on a Filter only. It is able to let the request continue to any of the servlets listening on a more specific URL pattern by calling FilterChain#doFilter().


The / doesn't override any other servlet. It only replaces the servletcontainer's builtin default servlet for all requests which doesn't match any other registered servlet. This is normally only invoked on static resources (CSS/JS/image/etc) and directory listings. The servletcontainer's builtin default servlet is also capable of dealing with HTTP cache requests, media (audio/video) streaming and file download resumes. Usually, you don't want to override the default servlet as you would otherwise have to take care of all its tasks, which is not exactly trivial (JSF utility library OmniFaces has an open source example). This is thus also a bad URL pattern for servlets. As to why JSP pages doesn't hit this servlet, it's because the servletcontainer's builtin JSP servlet will be invoked, which is already by default mapped on the more specific URL pattern *.jsp.


Then there's also the empty string URL pattern . This will be invoked when the context root is requested. This is different from the <welcome-file> approach that it isn't invoked when any subfolder is requested. This is most likely the URL pattern you're actually looking for in case you want a "home page servlet". I only have to admit that I'd intuitively expect the empty string URL pattern and the slash URL pattern / be defined exactly the other way round, so I can understand that a lot of starters got confused on this. But it is what it is.

Front Controller

In case you actually intend to have a front controller servlet, then you'd best map it on a more specific URL pattern like *.html, *.do, /pages/*, /app/*, etc. You can hide away the front controller URL pattern and cover static resources on a common URL pattern like /resources/*, /static/*, etc with help of a servlet filter. See also How to prevent static resources from being handled by front controller servlet which is mapped on /*. Noted should be that Spring MVC has a builtin static resource servlet, so that's why you could map its front controller on / if you configure a common URL pattern for static resources in Spring. See also How to handle static content in Spring MVC?

Merge 2 arrays of objects

Posting this because unlike the previous answers this one is generic, no external libraries, O(n), actually filters out the duplicate and keeps the order the OP is asking for (by placing the last matching element in place of first appearance):

function unique(array, keyfunc) {
    return array.reduce((result, entry) => {
        const key = keyfunc(entry)
        if(key in result.seen) {
            result.array[result.seen[key]] = entry
        } else {
            result.seen[key] = result.array.length
        return result
    }, { array: [], seen: {}}).array


var arr1 = new Array({name: "lang", value: "English"}, {name: "age", value: "18"})
var arr2 = new Array({name : "childs", value: '5'}, {name: "lang", value: "German"})

var arr3 = unique([...arr1, ...arr2], x =>
/* arr3 == [ 
    {name: "lang", value: "German"}, 
    {name: "age", value: "18"},
    {name: "childs", value: "5"}

grep output to show only matching file

Also remember one thing. Very important
You have to specify the command something like this to be more precise
grep -l "pattern" *

Regular Expression with wildcards to match any character

The following should work:

ABC: *\([a-zA-Z]+\) *(.+)


ABC:            # match literal characters 'ABC:'
 *              # zero or more spaces
\([a-zA-Z]+\)   # one or more letters inside of parentheses
 *              # zero or more spaces
(.+)            # capture one or more of any character (except newlines)

To get your desired grouping based on the comments below, you can use the following:

(ABC:) *(\([a-zA-Z]+\).+)

'pip install' fails for every package ("Could not find a version that satisfies the requirement")

Support for TLS 1.0 and 1.1 was dropped for PyPI. If your system does not use a more recent version, it could explain your error.

Could you try reinstalling pip system-wide, to update your system dependencies to a newer version of TLS?

This seems to be related to Unable to install Python libraries

See Dominique Barton's answer:

Apparently pip is trying to access PyPI via HTTPS (which is encrypted and fine), but with an old (insecure) SSL version. Your system seems to be out of date. It might help if you update your packages.

On Debian-based systems I'd try:

apt-get update && apt-get upgrade python-pip

On Red Hat Linux-based systems:

yum update python-pip # (or python2-pip, at least on Red Hat Linux 7)

On Mac:

sudo easy_install -U pip

You can also try to update openssl separately.

How can I iterate over files in a given directory?

I'm not quite happy with this implementation yet, I wanted to have a custom constructor that does DirectoryIndex._make(next(os.walk(input_path))) such that you can just pass the path you want a file listing for. Edits welcome!

import collections
import os

DirectoryIndex = collections.namedtuple('DirectoryIndex', ['root', 'dirs', 'files'])

for file_name in DirectoryIndex(*next(os.walk('.'))).files:
    file_path = os.path.join(path, file_name)

Installing Homebrew on OS X

It's on the top of the Homebrew homepage.

From a Terminal prompt:

ruby -e "$(curl -fsSL"

The command brew install wget is an example of how to use Homebrew to install another application (in this case, wget) after brew is already installed.


Above command to install the Brew is migrated to:

/bin/bash -c "$(curl -fsSL"

Using the RUN instruction in a Dockerfile with 'source' does not work

I also had issues in running source in a Dockerfile

This runs perfectly fine for building CentOS 6.6 Docker container, but gave issues in Debian containers

RUN cd ansible && source ./hacking/env-setup

This is how I tackled it, may not be an elegant way but this is what worked for me

RUN echo "source /ansible/hacking/env-setup" >> /tmp/setup
RUN /bin/bash -C "/tmp/setup"
RUN rm -f /tmp/setup

There is an error in XML document (1, 41)

In my case I had a float value expected where xml had a null value so be sure to search for float and int data type in your xsd map

The correct way to read a data file into an array

I like...

@data = `cat /var/tmp/somefile`;

It's not as glamorous as others, but, it works all the same. And...

$todays_data = '/var/tmp/somefile' ;
open INFILE, "$todays_data" ; 
@data = <INFILE> ; 
close INFILE ;


how to specify local modules as npm package dependencies

At work we have a common library that is used by a few different projects all in a single repository. Originally we used the published (private) version (npm install --save rp-utils) but that lead to a lot of needless version updates as we developed. The library lives in a sister directory to the applications and we are able to use a relative path instead of a version. Instead of "rp-utils": "^1.3.34" in package.json it now is:

  "dependencies": { ...
    "rp-utils": "../rp-utils",

the rp-utils directory contains a publishable npm package

How do I specify unique constraint for multiple columns in MySQL?

I have a MySQL table:

CREATE TABLE `content_html` (
  `id_box_elements` int(11) DEFAULT NULL,
  `id_router` int(11) DEFAULT NULL,
  `content` mediumtext COLLATE utf8_czech_ci NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id_box_elements` (`id_box_elements`,`id_router`)

and the UNIQUE KEY works just as expected, it allows multiple NULL rows of id_box_elements and id_router.

I am running MySQL 5.1.42, so probably there was some update on the issue discussed above. Fortunately it works and hopefully it will stay that way.

How to add a color overlay to a background image?

I see 2 easy options:

  • multiple background with a translucent single gradient over image
  • huge inset shadow

gradient option:

html {
  background:linear-gradient(0deg, rgba(255, 0, 150, 0.3), rgba(255, 0, 150, 0.3)), url(;

shadow option:

html {
  box-shadow:inset 0 0 0 2000px rgba(255, 0, 150, 0.3);

an old codepen of mine with few examples

a third option

  • with background-blen-mode :

    The background-blend-mode CSS property sets how an element's background images should blend with each other and with the element's background color.

html {
  background:url( rgba(255, 0, 150, 0.3);
  background-blend-mode: multiply;

Should Jquery code go in header or footer?

Put Scripts at the Bottom

The problem caused by scripts is that they block parallel downloads. The HTTP/1.1 specification suggests that browsers download no more than two components in parallel per hostname. If you serve your images from multiple hostnames, you can get more than two downloads to occur in parallel. While a script is downloading, however, the browser won't start any other downloads, even on different hostnames. In some situations it's not easy to move scripts to the bottom. If, for example, the script uses document.write to insert part of the page's content, it can't be moved lower in the page. There might also be scoping issues. In many cases, there are ways to workaround these situations.

An alternative suggestion that often comes up is to use deferred scripts. The DEFER attribute indicates that the script does not contain document.write, and is a clue to browsers that they can continue rendering. Unfortunately, Firefox doesn't support the DEFER attribute. In Internet Explorer, the script may be deferred, but not as much as desired. If a script can be deferred, it can also be moved to the bottom of the page. That will make your web pages load faster.

EDIT: Firefox does support the DEFER attribute since version 3.6.


Java LinkedHashMap get first or last entry

I would recommend using ConcurrentSkipListMap which has firstKey() and lastKey() methods

Different CURRENT_TIMESTAMP and SYSDATE in oracle

  • SYSDATE provides date and time of a server.
  • CURRENT_DATE provides date and time of client.(i.e., your system)
  • CURRENT_TIMESTAMP provides data and timestamp of a clinet.

Eclipse "Server Locations" section disabled and need to change to use Tomcat installation

Right click on the server, then Add/Remove, then remove any projects that are in the Configured panel. Then right click on the server and choose "Clean..." from the context menu. Then the Server Locations option will be enabled.

Material UI and Grid system

From the description of material design specs:

Grid Lists are an alternative to standard list views. Grid lists are distinct from grids used for layouts and other visual presentations.

If you are looking for a much lightweight Grid component library, I'm using React-Flexbox-Grid, the implementation of flexboxgrid.css in React.

On top of that, React-Flexbox-Grid played nicely with both material-ui, and react-toolbox (the alternative material design implementation).

how I can show the sum of in a datagridview column?

Fast and clean way using LINQ

int total = dataGridView1.Rows.Cast<DataGridViewRow>()
                .Sum(t => Convert.ToInt32(t.Cells[1].Value));

verified on VS2013

GitHub relative link in Markdown file

As of January 31, 2013 Github markdown supports relative links to files.

[a relative link](

However, there are a few deficiencies that have been discussed in this comment thread.

As an alternative, you can use Gitdown to construct full URLs to the repository and even make them branch aware, e.g.

{"gitdown": "gitinfo", "name": "url"} //
{"gitdown": "gitinfo", "name": "branch"} // master

Gitdown is a GitHub markdown preprocessor. It streamlines common tasks associated with maintaining a documentation page for a GitHub repository, e.g. generating table of contents, including variables, generating URLs and getting information about the repository itself at the time of processing the input. Gitdown seamlessly integrates with your building scripts.

I am the author of the Gitdown library.

Refresh page after form submitting

You can maybe use :

<form method="post" action=" " onSubmit="window.location.reload()">

"message failed to fetch from registry" while trying to install any module

One thing that has worked for me with random npm install errors (where the package that errors out is different under different times (but same environment) is to use this:

npm cache clean

And then repeat the process. Then the process seems to go smoother and the real problem and error message will emerge, where you can fix it and then proceed.

This is based on experience of running npm install of a whole bunch of packages under a pretty bare Ubuntu installation inside a Docker instance. Sometimes there are build/make tools missing from the Ubuntu and the npm errors will not show the real problem until you clean the cache for some reason.

Android Drawing Separator/Divider Line in Layout?

Adding this view; that draws a separator between your textviews

    android:background="#000000" />

how to update spyder on anaconda

One way to avoid errors during installing or updating packages is to run the Anaconda prompt as Administrator. Hope it helps!

Gradle build without tests

You can add the following lines to build.gradle, **/* excludes all the tests.

test {
    exclude '**/*'

Can't install APK from browser downloads

It shouldn't be HTTP headers if the file has been downloaded successfully and it's the same file that you can open from OI.

A shot in the dark, but could it be that you are not allowing installation from unknown sources, and that OI is somehow bypassing that?

Settings > Applications > Unknown sources...


Answer extracted from comments which worked. Ensure the Content-Type is set to application/

How to upgrade glibc from version 2.13 to 2.15 on Debian?

Your script contains errors as well, for example if you have dos2unix installed your install works but if you don't like I did then it will fail with dependency issues.

I found this by accident as I was making a script file of this to give to my friend who is new to Linux and because I made the scripts on windows I directed him to install it, at the time I did not have dos2unix installed thus I got errors.

here is a copy of the script I made for your solution but have dos2unix installed.

echo "deb sid main" >> /etc/apt/sources.list
apt-get update
apt-get -t sid install libc6 libc6-dev libc6-dbg
echo "Please remember to hash out sid main from your sources list. /etc/apt/sources.list"

this script has been tested on 3 machines with no errors.

How can I make setInterval also work when a tab is inactive in Chrome?

Just do this:

var $div = $('div');
var a = 0;

setInterval(function() {
    $div.stop(true,true).css("left", a);
}, 1000 / 30);

Inactive browser tabs buffer some of the setInterval or setTimeout functions.

stop(true,true) will stop all buffered events and execute immediatly only the last animation.

The window.setTimeout() method now clamps to send no more than one timeout per second in inactive tabs. In addition, it now clamps nested timeouts to the smallest value allowed by the HTML5 specification: 4 ms (instead of the 10 ms it used to clamp to).

Is there a need for range(len(a))?

My code is:

for I in range(len(s)):
    while not set(s[I])<=set('01'):s[i]=input(i)
print(bin(sum([int(x,2)for x in s]))[2:])

It is a binary adder but I don't think the range len or the inside can be replaced to make it smaller/better.

How to get the selected radio button value using js

Radio buttons come in groups which have the same name and different ids, one of them will have the checked property set to true, so loop over them until you find it.

function getCheckedRadio(radio_group) {
    for (var i = 0; i < radio_group.length; i++) {
        var button = radio_group[i];
        if (button.checked) {
            return button;
    return undefined;
var checkedButton = getCheckedRadio(document.forms.frmId.elements.groupName);
if (checkedButton) {
    alert("The value is " + checkedButton.value);

CSS Transition doesn't work with top, bottom, left, right

Something that is not relevant for the OP, but maybe for someone else in the future:

For pixels (px), if the value is "0", the unit can be omitted: right: 0 and right: 0px both work.

However I noticed that in Firefox and Chrome this is not the case for the seconds unit (s). While transition: right 1s ease 0s works, transition: right 1s ease 0 (missing unit s for last value transition-delay) does not (it does work in Edge however).

In the following example, you'll see that right works for both 0px and 0, but transition only works for 0s and it doesn't work with 0.

#box {_x000D_
    border: 1px solid black;_x000D_
    height: 240px;_x000D_
    width: 260px;_x000D_
    margin: 50px;_x000D_
    position: relative;_x000D_
.jump {_x000D_
    position: absolute;_x000D_
    width: 200px;_x000D_
    height: 50px;_x000D_
    color: white;_x000D_
    padding: 5px;_x000D_
#jump1 {_x000D_
    background-color: maroon;_x000D_
    top: 0px;_x000D_
    right: 0px;_x000D_
    transition: right 1s ease 0s;_x000D_
#jump2 {_x000D_
    background-color: green;_x000D_
    top: 60px;_x000D_
    right: 0;_x000D_
    transition: right 1s ease 0s;_x000D_
#jump3 {_x000D_
    background-color: blue;_x000D_
    top: 120px;_x000D_
    right: 0px;_x000D_
    transition: right 1s ease 0;_x000D_
#jump4 {_x000D_
    background-color: gray;_x000D_
    top: 180px;_x000D_
    right: 0;_x000D_
    transition: right 1s ease 0;_x000D_
#box:hover .jump {_x000D_
    right: 50px;_x000D_
<div id="box">_x000D_
  <div class="jump" id="jump1">right: 0px<br>transition: right 1s ease 0s</div>_x000D_
  <div class="jump" id="jump2">right: 0<br>transition: right 1s ease 0s</div>_x000D_
  <div class="jump" id="jump3">right: 0px<br>transition: right 1s ease 0</div>_x000D_
  <div class="jump" id="jump4">right: 0<br>transition: right 1s ease 0</div>_x000D_

Is it better practice to use String.format over string Concatenation in Java?

Generally, string concatenation should be prefered over String.format. The latter has two main disadvantages:

  1. It does not encode the string to be built in a local manner.
  2. The building process is encoded in a string.

By point 1, I mean that it is not possible to understand what a String.format() call is doing in a single sequential pass. One is forced to go back and forth between the format string and the arguments, while counting the position of the arguments. For short concatenations, this is not much of an issue. In these cases however, string concatenation is less verbose.

By point 2, I mean that the important part of the building process is encoded in the format string (using a DSL). Using strings to represent code has many disadvantages. It is not inherently type-safe, and complicates syntax-highlighting, code analysis, optimization, etc.

Of course, when using tools or frameworks external to the Java language, new factors can come into play.

Using a RegEx to match IP addresses in Python

import re
ipv=raw_input("Enter an ip address")
if m is not None:
    print "Valid sequence of input"
else :
    print "Invalid input sequence"

Just to keep it simple I have used this approach. Simple as in to explain how really ipv4 address is evaluated. Checking whether its a binary number is although not required. Hope you like this.

How to use Console.WriteLine in ASP.NET (C#) during debug?

You shouldn't launch as an IIS server. check your launch setting, make sure it switched to your project name( change this name in your launchSettings.json file ), not the IIS.

enter image description here

How to convert milliseconds to seconds with precision

Surely you just need:

double seconds = milliseconds / 1000.0;

There's no need to manually do the two parts separately - you just need floating point arithmetic, which the use of 1000.0 (as a double literal) forces. (I'm assuming your milliseconds value is an integer of some form.)

Note that as usual with double, you may not be able to represent the result exactly. Consider using BigDecimal if you want to represent 100ms as 0.1 seconds exactly. (Given that it's a physical quantity, and the 100ms wouldn't be exact in the first place, a double is probably appropriate, but...)

How do you install an APK file in the Android emulator?

keep your emulator up and running. In the command line, go inside the platform-tools folder, in your sdk folder which come with adt bundle and execute following command :

>adb install <yourFilename.apk>

This command detect your running emulator/emulators and show you the list of devices where you can install this app(show if any physical device/devices connected to your computer.). Then you can select any one, if only one emulator is running then app will directly installed on it by default.

Note: For above command your .apk file needs to be in same directory.

for more detailed tutorial follo : This link

R Not in subset

The expression df1$id %in% idNums1 produces a logical vector. To negate it, you need to negate the whole vector:

!(df1$id %in% idNums1)

telnet to port 8089 correct command

I believe telnet 8089 . Why don't u try both

Microsoft Advertising SDK doesn't deliverer ads

I only use MicrosoftAdvertising.Mobile and Microsoft.Advertising.Mobile.UI and I am served ads. The SDK should only add the DLLs not reference itself.

Note: You need to explicitly set width and height Make sure the phone dialer, and web browser capabilities are enabled

Followup note: Make sure that after you've removed the SDK DLL, that the xmlns references are not still pointing to it. The best route to take here is

  1. Remove the XAML for the ad
  2. Remove the xmlns declaration (usually at the top of the page, but sometimes will be declared in the ad itself)
  3. Remove the bad DLL (the one ending in .SDK )
  4. Do a Clean and then Build (clean out anything remaining from the DLL)
  5. Add the xmlns reference (actual reference is below)
  6. Add the ad to the page (example below)

Here is the xmlns reference:


Then the ad itself:

<AdNamespace:AdControl x:Name="myAd" Height="80" Width="480"                    AdUnitId="yourAdUnitIdHere" ApplicationId="yourIdHere"/> 

How to convert int[] into List<Integer> in Java?

The smallest piece of code would be:

public List<Integer> myWork(int[] array) {
    return Arrays.asList(ArrayUtils.toObject(array));

where ArrayUtils comes from commons-lang :)

Running PHP script from the command line

I was looking for a resolution to this issue in Windows, and it seems to be that if you don't have the environments vars ok, you need to put the complete directory. For eg. with a file in the same directory than PHP:

F:\myfolder\php\php.exe -f F:\myfolder\php\script.php

How to set tbody height with overflow scroll

In my case I wanted to have responsive table height instead of fixed height in pixels as the other answers are showing. To do that I used percentage of visible height property and overflow on div containing the table:

&__table-container {
  height: 70vh;
  overflow: scroll;

This way the table will expand along with the window being resized.

Switch/toggle div (jQuery)

I think you want this:




This is made possible by jQuery.

Pass variables between two PHP pages without using a form or the URL of page

Have you tried adding both to $_SESSION?

Then at the top of your page2.php just add:


Adding Lombok plugin to IntelliJ project

You need to Enable Annotation Processing on IntelliJ IDEA

> Settings > Build, Execution, Deployment > Compiler > Annotation Processors

enter image description here

How do I specify the platform for MSBuild?

For VS2017 and 2019... with the modern core library SDK project files, the platform can be changed during the build process. Here's an example to change to the anycpu platform, just before the built-in CoreCompile task runs:

<Project Sdk="Microsoft.NET.Sdk" >

  <Target Name="SwitchToAnyCpu" BeforeTargets="CoreCompile" >
    <Message Text="Current Platform=$(Platform)" />
    <Message Text="Current PlatformTarget=$(PlatformName)" />
    <Message Text="New Platform=$(Platform)" />
    <Message Text="New PlatformTarget=$(PlatformTarget)" />


In my case, I'm building an FPGA with BeforeTargets and AfterTargets tasks, but compiling a C# app in the main CoreCompile. (partly as I may want some sort of command-line app, and partly because I could not figure out how to omit or override CoreCompile)

To build for multiple, concurrent binaries such as x86 and x64: either a separate, manual build task would be needed or two separate project files with the respective <PlatformTarget>x86</PlatformTarget> and <PlatformTarget>x64</PlatformTarget> settings in the example, above.

Xcode error: Code signing is required for product type 'Application' in SDK 'iOS 10.0'

I had this error on my React Native project, weirdly enough I thought I was NOT editing the correct .xcodeproj file! I went into my project directory './appname/ios' and opened the project file and edited my team name into the project and it started working.

Delaying function in swift

For adding argument to delay function.

First setup a dictionary then add it as the userInfo. Unwrap the info with the timer as the argument.

let arg : Int = 42
let infoDict : [String : AnyObject] = ["argumentInt", arg]

NSTimer.scheduledTimerWithTimeInterval(NSTimeInterval(3), target: self, selector: "functionHereWithArgument:", userInfo: infoDict, repeats: false)

Then in the called function

func functionHereWithArgument (timer : NSTimer)
    if let userInfo = timer.userInfo as? Dictionary<String, AnyObject>
         let argumentInt : Int = (userInfo[argumentInt] as! Int)

Remove a folder from git tracking

From the git documentation:

Another useful thing you may want to do is to keep the file in your working tree but remove it from your staging area. In other words, you may want to keep the file on your hard drive but not have Git track it anymore. This is particularly useful if you forgot to add something to your .gitignore file and accidentally staged it, like a large log file or a bunch of .a compiled files. To do this, use the --cached option:

$ git rm --cached readme.txt

So maybe don't include the "-r"?

What is (functional) reactive programming?

Dude, this is a freaking brilliant idea! Why didn't I find out about this back in 1998? Anyway, here's my interpretation of the Fran tutorial. Suggestions are most welcome, I am thinking about starting a game engine based on this.

import pygame
from pygame.surface import Surface
from pygame.sprite import Sprite, Group
from pygame.locals import *
from time import time as epoch_delta
from math import sin, pi
from copy import copy

screen = pygame.display.set_mode((600,400))
pygame.display.set_caption('Functional Reactive System Demo')

class Time:
    def __float__(self):
        return epoch_delta()
time = Time()

class Function:
    def __init__(self, var, func, phase = 0., scale = 1., offset = 0.):
        self.var = var
        self.func = func
        self.phase = phase
        self.scale = scale
        self.offset = offset
    def copy(self):
        return copy(self)
    def __float__(self):
        return self.func(float(self.var) + float(self.phase)) * float(self.scale) + float(self.offset)
    def __int__(self):
        return int(float(self))
    def __add__(self, n):
        result = self.copy()
        result.offset += n
        return result
    def __mul__(self, n):
        result = self.copy()
        result.scale += n
        return result
    def __inv__(self):
        result = self.copy()
        result.scale *= -1.
        return result
    def __abs__(self):
        return Function(self, abs)

def FuncTime(func, phase = 0., scale = 1., offset = 0.):
    global time
    return Function(time, func, phase, scale, offset)

def SinTime(phase = 0., scale = 1., offset = 0.):
    return FuncTime(sin, phase, scale, offset)
sin_time = SinTime()

def CosTime(phase = 0., scale = 1., offset = 0.):
    phase += pi / 2.
    return SinTime(phase, scale, offset)
cos_time = CosTime()

class Circle:
    def __init__(self, x, y, radius):
        self.x = x
        self.y = y
        self.radius = radius
    def size(self):
        return [self.radius * 2] * 2
circle = Circle(
        x = cos_time * 200 + 250,
        y = abs(sin_time) * 200 + 50,
        radius = 50)

class CircleView(Sprite):
    def __init__(self, model, color = (255, 0, 0)):
        self.color = color
        self.model = model
        self.image = Surface([model.radius * 2] * 2).convert_alpha()
        self.rect = self.image.get_rect()
        pygame.draw.ellipse(self.image, self.color, self.rect)
    def update(self):
        self.rect[:] = int(self.model.x), int(self.model.y), self.model.radius * 2, self.model.radius * 2
circle_view = CircleView(circle)

sprites = Group(circle_view)
running = True
while running:
    for event in pygame.event.get():
        if event.type == QUIT:
            running = False
        if event.type == KEYDOWN and event.key == K_ESCAPE:
            running = False
    screen.fill((0, 0, 0))

In short: If every component can be treated like a number, the whole system can be treated like a math equation, right?

How to check for null in Twig?

Without any assumptions the answer is:

{% if var is null %}

But this will be true only if var is exactly NULL, and not any other value that evaluates to false (such as zero, empty string and empty array). Besides, it will cause an error if var is not defined. A safer way would be:

{% if var is not defined or var is null %}

which can be shortened to:

{% if var|default is null %}

If you don't provide an argument to the default filter, it assumes NULL (sort of default default). So the shortest and safest way (I know) to check whether a variable is empty (null, false, empty string/array, etc):

{% if var|default is empty %}

HTML/CSS--Creating a banner/header

Height is missing a p from its value.

Should be height:200*p*x

Convert audio files to mp3 using ffmpeg

Try FFmpeg Static Build Link


Host the static build on your server in same directory

$ffmpeg = dirname(__FILE__).'/ffmpeg';

$command = $ffmpeg.'ffmpeg -i audio.ogg -acodec libmp3lame audio.mp3';


How to use css style in php

css :hover kinda is like js onmouseover

row1 {
    // your css
row1:hover {
    color: red;
row1:hover #a, .b, .c:nth-child[3] {
    border: 1px solid red;

not too sure how it works but css applies styles to echo'ed ids

Should URL be case sensitive?

URLs should be case insensitive unless there is a good reason why they are should not be.

This is not mandatory (it is not any part of an RFC) but it makes the communication and storage of URLs far more reliable.

If I have two pages on a website:


How should they differ? Maybe one is written 'shouting style' (caps) - but from an IA point of view, the distinction should never be made by a change in the case of the URL.

Moreover, it is easy to implement this in Apache - just use CheckSpelling On from mod_Speling.

RestSharp JSON Parameter Posting

Here is complete console working application code. Please install RestSharp package.

using RestSharp;
using System;

namespace RESTSharpClient
    class Program
        static void Main(string[] args)
        string url = "";
        string jsonString = "{" +
                "\"auth\": {" +
                    "\"type\" : \"basic\"," +
                    "\"password\": \"@P&p@y_10364\"," +
                    "\"username\": \"prop_apiuser\"" +
                "}," +
                "\"requestId\" : 15," +
                "\"method\": {" +
                    "\"name\": \"getProperties\"," +
                    "\"params\": {" +
                        "\"showAllStatus\" : \"0\"" +
                    "}" +
                "}" +

        IRestClient client = new RestClient(url);
        IRestRequest request = new RestRequest("api/properties", Method.POST, DataFormat.Json);
        request.AddHeader("Content-Type", "application/json; CHARSET=UTF-8");

        var response = client.Execute(request);
        //TODO: do what you want to do with response.

How to run composer from anywhere?

How to run Composer From Anywhere (on MacOS X) via Terminal


Actually in getComposer website it clearly states that, install the Composer by using the following curl command,

curl -sS |php

And it certainly does what it's intended to do. And then it says to move the composer.phar to the directory /usr/local/bin/composer and then composer will be available Globally, by using the following command line in terminal!

mv composer.phar /usr/local/bin/composer


So the problem which leads me to Google over it is when I executed the above line in Mac OS X Terminal, it said that, Permission denied. Like as follows:

mv: rename composer.phar to /usr/local/bin/composer: Permission denied


Following link led me to the solution like a charm and I'm thankful to that. The thing I just missed was sudo command before the above stated "Move" command line. Now my Move command is as follows:

sudo mv composer.phar /usr/local/bin/composer

It directly prompts you to authenticate yourself and see if you are authorized. So if you enter a valid password, then the Moving will be done, and you can just check if composer is globally installed, by using the following line.

composer about

I hope this answer helped you to broaden your view and finally resolve your problem.


What is the difference between =Empty and IsEmpty() in VBA (Excel)?

From the Help:
IsEmpty returns True if the variable is uninitialized, or is explicitly set to Empty; otherwise, it returns False. False is always returned if expression contains more than one variable.
IsEmpty only returns meaningful information for variants.

To check if a cell is empty, you can use cell(x,y) = "".
You might eventually save time by using Range("X:Y").SpecialCells(xlCellTypeBlanks) or xlCellTypeConstants or xlCellTypeFormulas

android splash screen sizes for ldpi,mdpi, hdpi, xhdpi displays ? - eg : 1024X768 pixels for ldpi

For Android Mobile Devices

LDPI- icon-36x36, splash-426x320 (now with correct values)

MDPI- icon-48x48, splash-470x320

HDPI- icon 72x72, splash- 640x480

XHDPI- icon-96x96, splash- 960x720

XXHDPI- icon- 144x144

All in pixels.

For Android Tablet Devices

    Portrait: 200x320px
    Landscape: 320x200px
    Portrait: 320x480px
    Landscape: 480x320px
    Portrait: 480x800px
    Landscape: 800x480px
    Portrait: 720px1280px
    Landscape: 1280x720px

How to change Bootstrap's global default font size?

There are several ways but since you are using just the CSS version and not the SASS or LESS versions, your best bet to use Bootstraps own customization tool:

Customize whatever you want on this page and then you can download a custom build with your own font sizes and anything else you want to change.

Altering the CSS file directly (or simply adding new CSS styles that override the Bootstrap CSS) is not recommended because other Bootstrap styles' values are derived from the base font size. For example:

You can see that the base font size is used to calculate the sizes of the h1, h2, h3 etc. If you just changed the font size in the CSS (or added your own overriding font-size) all the other values that used the font size in calculations would no longer be proportionally accurate according to Bootstrap's design.

As I said, your best bet is to just use their own Customize tool. That is exactly what it's for.

If you are using SASS or LESS, you would change the font size in the variables file before compiling.

OpenJDK8 for windows

Go to this link

Download version tar.gz for windows and just extract files to the folder by your needs. On the left pane, you can select which version of openjdk to download

Tutorial: unzip as expected. You need to set system variable PATH to include your directory with openjdk so you can type java -version in console.

JDK vs OpenJDK

Convert UIImage to NSData and convert back to UIImage in Swift?

Image to Data:-

    if let img = UIImage(named: "xxx.png") {
        let pngdata = img.pngData()

   if let img = UIImage(named: "xxx.jpeg") {
        let jpegdata = img.jpegData(compressionQuality: 1)

Data to Image:-

 let image = UIImage(data: pngData)

Can anonymous class implement interface?

The best solution is just not to use anonymous classes.

public class Test
    class DummyInterfaceImplementor : IDummyInterface
        public string A { get; set; }
        public string B { get; set; }

    public void WillThisWork()
        var source = new DummySource[0];
        var values = from value in source
                     select new DummyInterfaceImplementor()
                         A = value.A,
                         B = value.C + "_" + value.D



    public void DoSomethingWithDummyInterface(IEnumerable<IDummyInterface> values)
        foreach (var value in values)
            Console.WriteLine("A = '{0}', B = '{1}'", value.A, value.B);

Note that you need to cast the result of the query to the type of the interface. There might be a better way to do it, but I couldn't find it.

Is it possible to specify the schema when connecting to postgres with JDBC?


When instantiating a DataSource implementation, look for a method to set the current/default schema.

For example, on the PGSimpleDataSource class call setCurrentSchema.

org.postgresql.ds.PGSimpleDataSource dataSource = new org.postgresql.ds.PGSimpleDataSource ( );
dataSource.setServerName ( "localhost" );
dataSource.setDatabaseName ( "your_db_here_" );
dataSource.setPortNumber ( 5432 );
dataSource.setUser ( "postgres" );
dataSource.setPassword ( "your_password_here" );
dataSource.setCurrentSchema ( "your_schema_name_here_" );  // <----------

If you leave the schema unspecified, Postgres defaults to a schema named public within the database. See the manual, section 5.9.2 The Public Schema. To quote hat manual:

In the previous sections we created tables without specifying any schema names. By default such tables (and other objects) are automatically put into a schema named “public”. Every new database contains such a schema.

Java TreeMap Comparator

You can not sort TreeMap on values.

A Red-Black tree based NavigableMap implementation. The map is sorted according to the natural ordering of its keys, or by a Comparator provided at map creation time, depending on which constructor is used You will need to provide comparator for Comparator<? super K> so your comparator should compare on keys.

To provide sort on values you will need SortedSet. Use

SortedSet<Map.Entry<String, Double>> sortedset = new TreeSet<Map.Entry<String, Double>>(
            new Comparator<Map.Entry<String, Double>>() {
                public int compare(Map.Entry<String, Double> e1,
                        Map.Entry<String, Double> e2) {
                    return e1.getValue().compareTo(e2.getValue());


To give you an example

    SortedMap<String, Double> myMap = new TreeMap<String, Double>();
    myMap.put("a", 10.0);
    myMap.put("b", 9.0);
    myMap.put("c", 11.0);
    myMap.put("d", 2.0);


  [d=2.0, b=9.0, a=10.0, c=11.0]

How to properly add 1 month from now to current date in moment.js

You could try

moment().add(1, 'M').subtract(1, 'day').format('DD-MM-YYYY')

Deserializing a JSON file with JavaScriptSerializer()

//Page load starts here

var json = new System.Web.Script.Serialization.JavaScriptSerializer().Serialize(new
    api_key = "my key",
    action = "categories",
    store_id = "my store"

var json2 = "{\"api_key\":\"my key\",\"action\":\"categories\",\"store_id\":\"my store\",\"user\" : {\"id\" : 12345,\"screen_name\" : \"twitpicuser\"}}";
var list = new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize<FooBar>(json);
var list2 = new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize<FooBar>(json2);

string a = list2.action;
var b = list2.user;
string c = b.screen_name;

//Page load ends here

public class FooBar
    public string api_key { get; set; }
    public string action { get; set; }
    public string store_id { get; set; }
    public User user { get; set; }

public class User
    public int id { get; set; }
    public string screen_name { get; set; }

Is there a timeout for idle PostgreSQL connections?

In PostgreSQL 9.6, there's a new option idle_in_transaction_session_timeout which should accomplish what you describe. You can set it using the SET command, e.g.:

SET SESSION idle_in_transaction_session_timeout = '5min';

ImportError: No module named Image

On a system with both Python 2 and 3 installed and with pip2-installed Pillow failing to provide Image, it is possible to install PIL for Python 2 in a way that will solve ImportError: No module named Image:

easy_install-2.7 --user PIL


sudo easy_install-2.7 PIL

How can I strip first X characters from string using sed?

pipe it through awk '{print substr($0,42)}' where 42 is one more than the number of characters to drop. For example:

$ echo abcde| awk '{print substr($0,2)}'

How to serialize an object into a string

How about writing the data to a ByteArrayOutputStream instead of a FileOutputStream?

Otherwise, you could serialize the object using XMLEncoder, persist the XML, then deserialize via XMLDecoder.

Actionbar notification count icon (badge) like Google has

I don't like ActionView based solutions, my idea is:

  1. create a layout with TextView, that TextView will be populated by application
  2. when you need to draw a MenuItem:

    2.1. inflate layout

    2.2. call measure() & layout() (otherwise view will be 0px x 0px, it's too small for most use cases)

    2.3. set the TextView's text

    2.4. make "screenshot" of the view

    2.6. set MenuItem's icon based on bitmap created on 2.4

  3. profit!

so, result should be something like enter image description here

  1. create layout here is a simple example
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android=""
        android:layout_height="wrap_content" >

            android:background="@drawable/unread_background" />

            android:textColor="#FFFFFF" />

@drawable/unread_background is that green TextView's background, @drawable/ic_menu_gallery is not really required here, it's just to preview layout's result in IDE.

  1. add code into onCreateOptionsMenu/onPrepareOptionsMenu

    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(, menu);
        MenuItem menuItem = menu.findItem(;
        menuItem.setIcon(buildCounterDrawable(count, R.drawable.ic_menu_gallery));
        return true;
  2. Implement build-the-icon method:

    private Drawable buildCounterDrawable(int count, int backgroundImageId) {
        LayoutInflater inflater = LayoutInflater.from(this);
        View view = inflater.inflate(R.layout.counter_menuitem_layout, null);
        if (count == 0) {
            View counterTextPanel = view.findViewById(;
        } else {
            TextView textView = (TextView) view.findViewById(;
            textView.setText("" + count);
                View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
                View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
        view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
        Bitmap bitmap = Bitmap.createBitmap(view.getDrawingCache());
        return new BitmapDrawable(getResources(), bitmap);

The complete code is here:

SQL SERVER, SELECT statement with auto generate row id

Do you want an incrementing integer column returned with your recordset? If so: -

--Check for existance  
if  exists (select * from dbo.sysobjects where [id] = object_id(N'dbo.t') AND objectproperty(id, N'IsUserTable') = 1)  
drop table dbo.t

--create dummy table and insert data  
create table dbo.t(x char(1) not null primary key, y char(1) not null)  
set nocount on  
insert dbo.t (x,y) values ('A','B')  
insert dbo.t (x,y) values ('C','D')  
insert dbo.t (x,y) values ('E','F')

--create temp table to add an identity column  
create table dbo.#TempWithIdentity(i int not null identity(1,1) primary key,x char(1) not null unique,y char(1) not null)  

--populate the temporary table  
insert into dbo.#TempWithIdentity(x,y) select x,y from dbo.t

--return the data  
select i,x,y from dbo.#TempWithIdentity

--clean up  
drop table dbo.#TempWithIdentity

Javascript array value is undefined ... how do I test for that

There are more (many) ways to Rome:

//=>considering predQuery[preId] is undefined:
predQuery[preId] === undefined; //=> true
undefined === predQuery[preId] //=> true
predQuery[preId] || 'it\'s unbelievable!' //=> it's unbelievable
var isdef = predQuery[preId] ? predQuery[preId] : null //=> isdef = null


Access blocked by CORS policy: Response to preflight request doesn't pass access control check

You may need to config the CORS at Spring Boot side. Please add below class in your Project.

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

public class WebConfig implements Filter,WebMvcConfigurer {

    public void addCorsMappings(CorsRegistry registry) {

    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) {
      HttpServletResponse response = (HttpServletResponse) res;
      HttpServletRequest request = (HttpServletRequest) req;
      System.out.println("WebConfig; "+request.getRequestURI());
      response.setHeader("Access-Control-Allow-Origin", "*");
      response.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE");
      response.setHeader("Access-Control-Allow-Headers", "Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With,observe");
      response.setHeader("Access-Control-Max-Age", "3600");
      response.setHeader("Access-Control-Allow-Credentials", "true");
      response.setHeader("Access-Control-Expose-Headers", "Authorization");
      response.addHeader("Access-Control-Expose-Headers", "responseType");
      response.addHeader("Access-Control-Expose-Headers", "observe");
      System.out.println("Request Method: "+request.getMethod());
      if (!(request.getMethod().equalsIgnoreCase("OPTIONS"))) {
          try {
              chain.doFilter(req, res);
          } catch(Exception e) {
      } else {
          response.setHeader("Access-Control-Allow-Origin", "*");
          response.setHeader("Access-Control-Allow-Methods", "POST,GET,DELETE,PUT");
          response.setHeader("Access-Control-Max-Age", "3600");
          response.setHeader("Access-Control-Allow-Headers", "Access-Control-Expose-Headers"+"Authorization, content-type," +




To append Token to each request you can create one Interceptor as below.

import { Injectable } from '@angular/core';
import { HttpEvent, HttpHandler, HttpInterceptor, HttpRequest } from '@angular/common/http';
import { Observable } from 'rxjs';

export class AuthInterceptor implements HttpInterceptor {

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const token = window.localStorage.getItem('tokenKey'); // you probably want to store it in localStorage or something

    if (!token) {
      return next.handle(req);

    const req1 = req.clone({
      headers: req.headers.set('Authorization', `${token}`),

    return next.handle(req1);



minimize app to system tray

try this

 private void Form1_Load(object sender, EventArgs e)
        notifyIcon1.BalloonTipText = "Application Minimized.";
        notifyIcon1.BalloonTipTitle = "test";

    private void Form1_Resize(object sender, EventArgs e)
        if (WindowState == FormWindowState.Minimized)
            ShowInTaskbar = false;
            notifyIcon1.Visible = true;

    private void notifyIcon1_MouseDoubleClick(object sender, MouseEventArgs e)
        ShowInTaskbar = true;
        notifyIcon1.Visible = false;
        WindowState = FormWindowState.Normal;

How to check programmatically if an application is installed or not in Android?

All the answers only check certain app is installed or not. But, as we all know an app can be installed but disabled by the user, unusable.

Therefore, this solution checks for both. i.e, installed AND enabled apps.

public static boolean isPackageInstalled(String packageName, PackageManager packageManager) {
     try {
          return packageManager.getApplicationInfo(packageName, 0).enabled;
     catch (PackageManager.NameNotFoundException e) {
          return false;

Call the method isPackageInstalled():

boolean isAppInstalled = isPackageInstalled("" , this.getPackageManager());

Now, use the boolean variable isAppInstalled and do whatever you want.

if(isAppInstalled ) {
    /* do whatever you want */

TypeError: 'undefined' is not a function (evaluating '$(document)')

Also check for including jQuery, followed by some components/other libraries (like jQuery UI) and then accidentially including jQuery again - this will redefine jQuery and drop the component helpers (like .datepicker) off the instance.

Eclipse: Enable autocomplete / content assist

  1. window->preferences->java->Editor->Contest Assist
  2. Enter in Auto activation triggers for java:
  3. Apply and Close

other method:
type initial letter then ctrl+spacebar for auto-complete options.

Add one day to date in javascript

If you don't mind using a library, DateJS ( would make this fairly easy. You would probably be better off with one of the answers using vanilla JavaScript however, unless you're going to take advantage of some other DateJS features like parsing of unusually-formatted dates.

If you're using DateJS a line like this should do the trick:


You could also use MomentJS which has similar features (, however I'm not as familiar with it.

How to change button text in Swift Xcode 6?

In Swift 4 I tried all of this previously, but runs only:

@IBAction func myButton(sender: AnyObject) {
   sender.setTitle("This is example text one", for:[])
   sender.setTitle("This is example text two", for: .normal)

Close Android Application

You could close your Android Application by calling System.exit(0).

Web Application Problems (web.config errors) HTTP 500.19 with IIS7.5 and ASP.NET v2

Same issue on Server 2016, IIS 10, 500.19 error. I installed the redirect module and it worked. I do not know why this was not included by default.

To be clear it looks like the web.config from IIS 7 will work, or is designed to work, but the lack of this module gives the really odd and unhelpful error. Googling takes you to a Microsoft page which insists that your site is corrupted or your web.config is corrupted. Neither seems to be the case.

That unhelpful page is here:

How should I do integer division in Perl?

you can:

use integer;

it is explained by Michael Ratanapintha or else use manually:



notice, 'int' is not casting. this is function for converting number to integer form. this is because Perl 5 does not have separate integer division. exception is when you 'use integer'. Then you will lose real division.

How do I avoid the specification of the username and password at every git push?

Permanently authenticating with Git repositories,

Run the following command to enable credential caching.

$ git config credential.helper store
$ git push

Username for '': <USERNAME>
Password for 'https://[email protected]': <PASSWORD>

Use should also specify caching expire,

git config --global credential.helper 'cache --timeout 7200'

After enabling credential caching, it will be cached for 7200 seconds (2 hours).

Note: Credential helper stores an unencrypted password on a local disk.

Press enter in textbox to and execute button command

You can handle the keydown event of your TextBox control.

private void textBox1_KeyDown(object sender, KeyEventArgs e)

It works even when the button Visible property is set to false

Java Replace Character At Specific Position Of String?

To replace a character at a specified position :

public static String replaceCharAt(String s, int pos, char c) {
   return s.substring(0,pos) + c + s.substring(pos+1);

How to import/include a CSS file using PHP code and not HTML code?

To use "include" to include CSS, you have to tell PHP you're using CSS code. Add this to your header of your CSS file and make it main.php (or styles.css, or whatever):

header("Content-type: text/css; charset: UTF-8");

This might help with some user's connections, but it theoretically (read: I haven't tested it) adds processor overhead to your server and according to Steve Souder, because your computer can download multiple files at once, using include could be slower. If you have your CSS split into a dozen files, maybe it would be faster?

Steve's blog post: Source:

What's the difference between eval, exec, and compile?

The short answer, or TL;DR

Basically, eval is used to evaluate a single dynamically generated Python expression, and exec is used to execute dynamically generated Python code only for its side effects.

eval and exec have these two differences:

  1. eval accepts only a single expression, exec can take a code block that has Python statements: loops, try: except:, class and function/method definitions and so on.

    An expression in Python is whatever you can have as the value in a variable assignment:

    a_variable = (anything you can put within these parentheses is an expression)
  2. eval returns the value of the given expression, whereas exec ignores the return value from its code, and always returns None (in Python 2 it is a statement and cannot be used as an expression, so it really does not return anything).

In versions 1.0 - 2.7, exec was a statement, because CPython needed to produce a different kind of code object for functions that used exec for its side effects inside the function.

In Python 3, exec is a function; its use has no effect on the compiled bytecode of the function where it is used.

Thus basically:

>>> a = 5
>>> eval('37 + a')   # it is an expression
>>> exec('37 + a')   # it is an expression statement; value is ignored (None is returned)
>>> exec('a = 47')   # modify a global variable as a side effect
>>> a
>>> eval('a = 47')  # you cannot evaluate a statement
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1
    a = 47
SyntaxError: invalid syntax

The compile in 'exec' mode compiles any number of statements into a bytecode that implicitly always returns None, whereas in 'eval' mode it compiles a single expression into bytecode that returns the value of that expression.

>>> eval(compile('42', '<string>', 'exec'))  # code returns None
>>> eval(compile('42', '<string>', 'eval'))  # code returns 42
>>> exec(compile('42', '<string>', 'eval'))  # code returns 42,
>>>                                          # but ignored by exec

In the 'eval' mode (and thus with the eval function if a string is passed in), the compile raises an exception if the source code contains statements or anything else beyond a single expression:

>>> compile('for i in range(3): print(i)', '<string>', 'eval')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1
    for i in range(3): print(i)
SyntaxError: invalid syntax

Actually the statement "eval accepts only a single expression" applies only when a string (which contains Python source code) is passed to eval. Then it is internally compiled to bytecode using compile(source, '<string>', 'eval') This is where the difference really comes from.

If a code object (which contains Python bytecode) is passed to exec or eval, they behave identically, excepting for the fact that exec ignores the return value, still returning None always. So it is possible use eval to execute something that has statements, if you just compiled it into bytecode before instead of passing it as a string:

>>> eval(compile('if 1: print("Hello")', '<string>', 'exec'))

works without problems, even though the compiled code contains statements. It still returns None, because that is the return value of the code object returned from compile.

In the 'eval' mode (and thus with the eval function if a string is passed in), the compile raises an exception if the source code contains statements or anything else beyond a single expression:

>>> compile('for i in range(3): print(i)', '<string>'. 'eval')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1
    for i in range(3): print(i)
SyntaxError: invalid syntax

The longer answer, a.k.a the gory details

exec and eval

The exec function (which was a statement in Python 2) is used for executing a dynamically created statement or program:

>>> program = '''
for i in range(3):
    print("Python is cool")
>>> exec(program)
Python is cool
Python is cool
Python is cool

The eval function does the same for a single expression, and returns the value of the expression:

>>> a = 2
>>> my_calculation = '42 * a'
>>> result = eval(my_calculation)
>>> result

exec and eval both accept the program/expression to be run either as a str, unicode or bytes object containing source code, or as a code object which contains Python bytecode.

If a str/unicode/bytes containing source code was passed to exec, it behaves equivalently to:

exec(compile(source, '<string>', 'exec'))

and eval similarly behaves equivalent to:

eval(compile(source, '<string>', 'eval'))

Since all expressions can be used as statements in Python (these are called the Expr nodes in the Python abstract grammar; the opposite is not true), you can always use exec if you do not need the return value. That is to say, you can use either eval('my_func(42)') or exec('my_func(42)'), the difference being that eval returns the value returned by my_func, and exec discards it:

>>> def my_func(arg):
...     print("Called with %d" % arg)
...     return arg * 2
>>> exec('my_func(42)')
Called with 42
>>> eval('my_func(42)')
Called with 42

Of the 2, only exec accepts source code that contains statements, like def, for, while, import, or class, the assignment statement (a.k.a a = 42), or entire programs:

>>> exec('for i in range(3): print(i)')
>>> eval('for i in range(3): print(i)')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1
    for i in range(3): print(i)
SyntaxError: invalid syntax

Both exec and eval accept 2 additional positional arguments - globals and locals - which are the global and local variable scopes that the code sees. These default to the globals() and locals() within the scope that called exec or eval, but any dictionary can be used for globals and any mapping for locals (including dict of course). These can be used not only to restrict/modify the variables that the code sees, but are often also used for capturing the variables that the executed code creates:

>>> g = dict()
>>> l = dict()
>>> exec('global a; a, b = 123, 42', g, l)
>>> g['a']
>>> l
{'b': 42}

(If you display the value of the entire g, it would be much longer, because exec and eval add the built-ins module as __builtins__ to the globals automatically if it is missing).

In Python 2, the official syntax for the exec statement is actually exec code in globals, locals, as in

>>> exec 'global a; a, b = 123, 42' in g, l

However the alternate syntax exec(code, globals, locals) has always been accepted too (see below).


The compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1) built-in can be used to speed up repeated invocations of the same code with exec or eval by compiling the source into a code object beforehand. The mode parameter controls the kind of code fragment the compile function accepts and the kind of bytecode it produces. The choices are 'eval', 'exec' and 'single':

  • 'eval' mode expects a single expression, and will produce bytecode that when run will return the value of that expression:

    >>> dis.dis(compile('a + b', '<string>', 'eval'))
      1           0 LOAD_NAME                0 (a)
                  3 LOAD_NAME                1 (b)
                  6 BINARY_ADD
                  7 RETURN_VALUE
  • 'exec' accepts any kinds of python constructs from single expressions to whole modules of code, and executes them as if they were module top-level statements. The code object returns None:

    >>> dis.dis(compile('a + b', '<string>', 'exec'))
      1           0 LOAD_NAME                0 (a)
                  3 LOAD_NAME                1 (b)
                  6 BINARY_ADD
                  7 POP_TOP                             <- discard result
                  8 LOAD_CONST               0 (None)   <- load None on stack
                 11 RETURN_VALUE                        <- return top of stack
  • 'single' is a limited form of 'exec' which accepts a source code containing a single statement (or multiple statements separated by ;) if the last statement is an expression statement, the resulting bytecode also prints the repr of the value of that expression to the standard output(!).

    An if-elif-else chain, a loop with else, and try with its except, else and finally blocks is considered a single statement.

    A source fragment containing 2 top-level statements is an error for the 'single', except in Python 2 there is a bug that sometimes allows multiple toplevel statements in the code; only the first is compiled; the rest are ignored:

    In Python 2.7.8:

    >>> exec(compile('a = 5\na = 6', '<string>', 'single'))
    >>> a

    And in Python 3.4.2:

    >>> exec(compile('a = 5\na = 6', '<string>', 'single'))
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<string>", line 1
        a = 5
    SyntaxError: multiple statements found while compiling a single statement

    This is very useful for making interactive Python shells. However, the value of the expression is not returned, even if you eval the resulting code.

Thus greatest distinction of exec and eval actually comes from the compile function and its modes.

In addition to compiling source code to bytecode, compile supports compiling abstract syntax trees (parse trees of Python code) into code objects; and source code into abstract syntax trees (the ast.parse is written in Python and just calls compile(source, filename, mode, PyCF_ONLY_AST)); these are used for example for modifying source code on the fly, and also for dynamic code creation, as it is often easier to handle the code as a tree of nodes instead of lines of text in complex cases.

While eval only allows you to evaluate a string that contains a single expression, you can eval a whole statement, or even a whole module that has been compiled into bytecode; that is, with Python 2, print is a statement, and cannot be evalled directly:

>>> eval('for i in range(3): print("Python is cool")')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1
    for i in range(3): print("Python is cool")
SyntaxError: invalid syntax

compile it with 'exec' mode into a code object and you can eval it; the eval function will return None.

>>> code = compile('for i in range(3): print("Python is cool")',
                   '', 'exec')
>>> eval(code)
Python is cool
Python is cool
Python is cool

If one looks into eval and exec source code in CPython 3, this is very evident; they both call PyEval_EvalCode with same arguments, the only difference being that exec explicitly returns None.

Syntax differences of exec between Python 2 and Python 3

One of the major differences in Python 2 is that exec is a statement and eval is a built-in function (both are built-in functions in Python 3). It is a well-known fact that the official syntax of exec in Python 2 is exec code [in globals[, locals]].

Unlike majority of the Python 2-to-3 porting guides seem to suggest, the exec statement in CPython 2 can be also used with syntax that looks exactly like the exec function invocation in Python 3. The reason is that Python 0.9.9 had the exec(code, globals, locals) built-in function! And that built-in function was replaced with exec statement somewhere before Python 1.0 release.

Since it was desirable to not break backwards compatibility with Python 0.9.9, Guido van Rossum added a compatibility hack in 1993: if the code was a tuple of length 2 or 3, and globals and locals were not passed into the exec statement otherwise, the code would be interpreted as if the 2nd and 3rd element of the tuple were the globals and locals respectively. The compatibility hack was not mentioned even in Python 1.4 documentation (the earliest available version online); and thus was not known to many writers of the porting guides and tools, until it was documented again in November 2012:

The first expression may also be a tuple of length 2 or 3. In this case, the optional parts must be omitted. The form exec(expr, globals) is equivalent to exec expr in globals, while the form exec(expr, globals, locals) is equivalent to exec expr in globals, locals. The tuple form of exec provides compatibility with Python 3, where exec is a function rather than a statement.

Yes, in CPython 2.7 that it is handily referred to as being a forward-compatibility option (why confuse people over that there is a backward compatibility option at all), when it actually had been there for backward-compatibility for two decades.

Thus while exec is a statement in Python 1 and Python 2, and a built-in function in Python 3 and Python 0.9.9,

>>> exec("print(a)", globals(), {'a': 42})

has had identical behaviour in possibly every widely released Python version ever; and works in Jython 2.5.2, PyPy 2.3.1 (Python 2.7.6) and IronPython 2.6.1 too (kudos to them following the undocumented behaviour of CPython closely).

What you cannot do in Pythons 1.0 - 2.7 with its compatibility hack, is to store the return value of exec into a variable:

Python 2.7.11+ (default, Apr 17 2016, 14:00:29) 
[GCC 5.3.1 20160413] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> a = exec('print(42)')
  File "<stdin>", line 1
    a = exec('print(42)')
SyntaxError: invalid syntax

(which wouldn't be useful in Python 3 either, as exec always returns None), or pass a reference to exec:

>>> call_later(exec, 'print(42)', delay=1000)
  File "<stdin>", line 1
    call_later(exec, 'print(42)', delay=1000)
SyntaxError: invalid syntax

Which a pattern that someone might actually have used, though unlikely;

Or use it in a list comprehension:

>>> [exec(i) for i in ['print(42)', 'print(foo)']
  File "<stdin>", line 1
    [exec(i) for i in ['print(42)', 'print(foo)']
SyntaxError: invalid syntax

which is abuse of list comprehensions (use a for loop instead!).

Javascript one line If...else...else if statement

In simple words:

var x = (day == "yes") ? "Good Day!" : (day == "no") ? "Good Night!" : "";

How do I create a datetime in Python from milliseconds?

Just convert it to timestamp


List all files and directories in a directory + subdirectories

If you don't have access to a subfolder inside the directory tree, Directory.GetFiles stops and throws the exception resulting in a null value in the receiving string[].

Here, see this answer

It manages the exception inside the loop and keep on working untill the entire folder is traversed.

How to Set user name and Password of phpmyadmin

You can simply open the phpmyadmin page from your browser, then open any existing database -> go to Privileges tab, click on your root user and then a popup window will appear, you can set your password there.. Hope this Helps.

How do I get the latest version of my code?

If you just want to throw away everything in your working folder (eg the results of a failed or aborted merge) and revert to a clean previous commit, do a git reset --hard.

Visual Studio 2017 error: Unable to start program, An operation is not legal in the current state

Incase you are not able to resolve the issue in any other way, then try this(it worked for me!):

Keep this below code into your web config file then rename value="yourwebformname.aspx"

          <add value="insertion.aspx" />
    <directoryBrowse enabled="false" />

else Try:

    <directoryBrowse enabled="true" />

Getting JavaScript object key list

var obj = {_x000D_
   key1: 'value1',_x000D_
   key2: 'value2',_x000D_
   key3: 'value3',_x000D_
   key4: 'value4'_x000D_
var keys = Object.keys(obj);_x000D_
console.log('obj contains ' + keys.length + ' keys: '+  keys);

It's supported on most major browsers now.

Simplest way to download and unzip files in Node.js cross-platform?

Another working example:

var zlib = require('zlib');
var tar = require('tar');
var ftp = require('ftp');

var files = [];

var conn = new ftp();
conn.on('connect', function(e) 
        if (e)
            throw e;
        conn.get('/tz/tzdata-latest.tar.gz', function(e, stream) 
            stream.on('success', function() 

                console.log("Processing files ...");

                for (var name in files)
                    var file = files[name];

                    console.log("filename: " + name);
            stream.on('error', function(e) 
                console.log('ERROR during get(): ' + e);

            console.log("Reading ...");

            .on("entry", function (e) 
                var filename = e.props["path"];
                console.log("filename:" + filename);
                if( files[filename] == null )
                    files[filename] = "";
                e.on("data", function (c) 
                    files[filename] += c.toString();
.connect(21, "");

Is double square brackets [[ ]] preferable over single square brackets [ ] in Bash?

If you are into following Google's style guide:

Test, [ and [[

[[ ... ]] reduces errors as no path name expansion or word splitting takes place between [[ and ]], and [[ ... ]] allows for regular expression matching where [ ... ] does not.

# This ensures the string on the left is made up of characters in the
# alnum character class followed by the string name.
# Note that the RHS should not be quoted here.
# For the gory details, see
# E14 at
if [[ "filename" =~ ^[[:alnum:]]+name ]]; then
  echo "Match"

# This matches the exact pattern "f*" (Does not match in this case)
if [[ "filename" == "f*" ]]; then
  echo "Match"

# This gives a "too many arguments" error as f* is expanded to the
# contents of the current directory
if [ "filename" == f* ]; then
  echo "Match"

Install a Nuget package in Visual Studio Code

You can use the NuGet Package Manager extension.

After you've installed it, to add a package, press Ctrl+Shift+P, and type >nuget and press Enter:

enter image description here

Type a part of your package's name as search string:

enter image description here

Choose the package:

enter image description here

And finally the package version (you probably want the newest one):

enter image description here

How to convert CSV file to multiline JSON?

import csv
import json

file = 'csv_file_name.csv'
json_file = 'output_file_name.json'

#Read CSV File
def read_CSV(file, json_file):
    csv_rows = []
    with open(file) as csvfile:
        reader = csv.DictReader(csvfile)
        field = reader.fieldnames
        for row in reader:
            csv_rows.extend([{field[i]:row[field[i]] for i in range(len(field))}])
        convert_write_json(csv_rows, json_file)

#Convert csv data into json
def convert_write_json(data, json_file):
    with open(json_file, "w") as f:
        f.write(json.dumps(data, sort_keys=False, indent=4, separators=(',', ': '))) #for pretty


Documentation of json.dumps()

Algorithm to return all combinations of k elements from n

Another one solution with C#:

 static List<List<T>> GetCombinations<T>(List<T> originalItems, int combinationLength)
        if (combinationLength < 1)
            return null;

        return CreateCombinations<T>(new List<T>(), 0, combinationLength, originalItems);

 static List<List<T>> CreateCombinations<T>(List<T> initialCombination, int startIndex, int length, List<T> originalItems)
        List<List<T>> combinations = new List<List<T>>();
        for (int i = startIndex; i < originalItems.Count - length + 1; i++)
            List<T> newCombination = new List<T>(initialCombination);
            if (length > 1)
                List<List<T>> newCombinations = CreateCombinations(newCombination, i + 1, length - 1, originalItems);

        return combinations;

Example of usage:

   List<char> initialArray = new List<char>() { 'a','b','c','d'};
   int combinationLength = 3;
   List<List<char>> combinations = GetCombinations(initialArray, combinationLength);

What is __future__ in Python used for and how/when to use it, and how it works

Or is it like saying "Since this is python v2.7, use that different 'print' function that has also been added to python v2.7, after it was added in python 3. So my 'print' will no longer be statements (eg print "message" ) but functions (eg, print("message", options). That way when my code is run in python 3, 'print' will not break."


from __future__ import print_function

print_function is the module containing the new implementation of 'print' as per how it is behaving in python v3.

This has more explanation:

Do I commit the package-lock.json file created by npm 5?

Yes, you SHOULD:

  1. commit the package-lock.json.
  2. use npm ci instead of npm install when building your applications both on your CI and your local development machine

The npm ci workflow requires the existence of a package-lock.json.

A big downside of npm install command is its unexpected behavior that it may mutate the package-lock.json, whereas npm ci only uses the versions specified in the lockfile and produces an error

  • if the package-lock.json and package.json are out of sync
  • if a package-lock.json is missing.

Hence, running npm install locally, esp. in larger teams with multiple developers, may lead to lots of conflicts within the package-lock.json and developers to decide to completely delete the package-lock.json instead.

Yet there is a strong use-case for being able to trust that the project's dependencies resolve repeatably in a reliable way across different machines.

From a package-lock.json you get exactly that: a known-to-work state.

In the past, I had projects without package-lock.json / npm-shrinkwrap.json / yarn.lock files whose build would fail one day because a random dependency got a breaking update.

Those issue are hard to resolve as you sometimes have to guess what the last working version was.

If you want to add a new dependency, you still run npm install {dependency}. If you want to upgrade, use either npm update {dependency} or npm install ${dependendency}@{version} and commit the changed package-lock.json.

If an upgrade fails, you can revert to the last known working package-lock.json.

To quote npm doc:

It is highly recommended you commit the generated package lock to source control: this will allow anyone else on your team, your deployments, your CI/continuous integration, and anyone else who runs npm install in your package source to get the exact same dependency tree that you were developing on. Additionally, the diffs from these changes are human-readable and will inform you of any changes npm has made to your node_modules, so you can notice if any transitive dependencies were updated, hoisted, etc.

And in regards to the difference between npm ci vs npm install:

  • The project must have an existing package-lock.json or npm-shrinkwrap.json.
  • If dependencies in the package lock do not match those in package.json, npm ci will exit with an error, instead of updating the package lock.
  • npm ci can only install entire projects at a time: individual dependencies cannot be added with this command.
  • If a node_modules is already present, it will be automatically removed before npm ci begins its install.
  • It will never write to package.json or any of the package-locks: installs are essentially frozen.

Note: I posted a similar answer here

Set a request header in JavaScript

For people looking this up now:

It seems that now setting the User-Agent header is allowed since Firefox 43. See for the current list of forbidden headers.

Xcode 10: A valid provisioning profile for this executable was not found

Be aware that accepted answer prevents build to be uploaded to App Store Connect.

Regex matching beginning AND end strings


This should work you.

How do I free memory in C?

You have to free() the allocated memory in exact reverse order of how it was allocated using malloc().

Note that You should free the memory only after you are done with your usage of the allocated pointers.

memory allocation for 1D arrays:

    buffer = malloc(num_items*sizeof(double));

memory deallocation for 1D arrays:


memory allocation for 2D arrays:

    double **cross_norm=(double**)malloc(150 * sizeof(double *));
    for(i=0; i<150;i++)

memory deallocation for 2D arrays:

    for(i=0; i<150;i++)


How much data can a List can hold at the maximum?

Numbering an items in the java array should start from zero. This was i think we can have access to Integer.MAX_VALUE+1 an items.

how to wait for first command to finish?

Make sure that does something at the end what you can recognize (like touch /tmp/st_new.tmp when you remove the file first and always start one instance of
Then make a polling loop. First sleep the normal time you think you should wait, and wait short time in every loop. This will result in something like

sleep 10 # Minimum time for to finish
while [ ${retry} -lt ${max_retry} ]; do
   if [ -f /tmp/st_new.tmp ]; then
      break # call outside loop
      (( retry = retry + 1 ))
      sleep 1
if [ -f /tmp/st_new.tmp ]; then
   source ../../ 
   rm -f /tmp/st_new.tmp
   echo Something wrong with

How to create a signed APK file using Cordova command line interface?

For Windows, I've created a build.cmd file:

(replace the keystore path and alias)

For Cordova:

@echo off 
set /P spassw="Store Password: " && set /P kpassw="Key Password: " && cordova build android --release -- --keystore=../../local/my.keystore --storePassword=%spassw% --alias=tmpalias --password=%kpassw%

And for Ionic:

@echo off 
set /P spassw="Store Password: " && set /P kpassw="Key Password: " && ionic build --prod && cordova build android --release -- --keystore=../../local/my.keystore --storePassword=%spassw% --alias=tmpalias --password=%kpassw%

Save it in the ptoject's directory, you can double click or open it with cmd.

Debugging Stored Procedure in SQL Server 2008

MSDN has provided easy way to debug the stored procedure. Please check this link-
How to: Debug Stored Procedures

How to get controls in WPF to fill available space?

Use the HorizontalAlignment and VerticalAlignment layout properties. They control how an element uses the space it has inside its parent when more room is available than it required by the element.

The width of a StackPanel, for example, will be as wide as the widest element it contains. So, all narrower elements have a bit of excess space. The alignment properties control what the child element does with the extra space.

The default value for both properties is Stretch, so the child element is stretched to fill all available space. Additional options include Left, Center and Right for HorizontalAlignment and Top, Center and Bottom for VerticalAlignment.

How to read request body in an core webapi controller?

I had a similar issue when using ASP.NET Core 2.1:

  • I need a custom middleware to read the POSTed data and perform some security checks against it
  • using an authorization filter is not practical, due to large number of actions that are affected
  • I have to allow objects binding in the actions ([FromBody] someObject). Thanks to SaoBiz for pointing out this solution.

So, the obvious solution is to allow the request to be rewindable, but make sure that after reading the body, the binding still works.


public class EnableRequestRewindMiddleware
    private readonly RequestDelegate _next;

    public EnableRequestRewindMiddleware(RequestDelegate next)
        _next = next;

    /// <summary>
    /// </summary>
    /// <param name="context"></param>
    /// <returns></returns>
    public async Task Invoke(HttpContext context)
        await _next(context);


(place this at the beginning of Configure method)


Some other middleware

This is part of the middleware that requires unpacking of the POSTed information for checking stuff.

using (var stream = new MemoryStream())
    // make sure that body is read from the beginning
    context.Request.Body.Seek(0, SeekOrigin.Begin);
    string requestBody = Encoding.UTF8.GetString(stream.ToArray());

    // this is required, otherwise model binding will return null
    context.Request.Body.Seek(0, SeekOrigin.Begin);

python uninstall

I had run "python install" at some point in the past accidentally in my global environment, and had much difficulty uninstalling. These solutions didn't help. "pip uninstall " didn't work with "Can't uninstall 'splunk-appinspect'. No files were found to uninstall." "sudo pip uninstall " didn't work "Cannot uninstall requirement splunk-appinspect, not installed". I tried uninstalling pip, deleting the pip cache, searching my hard drive for the package, etc...

"pip show " eventually led me to the solution, the "Location:" was pointing to a directory, and renaming that directory caused the packaged to be removed from pip's list. I renamed the directory back, and it didn't reappear in pip's list, and now I can reinstall my package in a virtualenv.

Two versions of python on linux. how to make 2.7 the default

You probably don't actually want to change your default Python.

Your distro installed a standard system Python in /usr/bin, and may have scripts that depend on this being present, and selected by #! /usr/bin/env python. You can usually get away with running Python 2.6 scripts in 2.7, but do you want to risk it?

On top of that, monkeying with /usr/bin can break your package manager's ability to manage packages. And changing the order of directories in your PATH will affect a lot of other things besides Python. (In fact, it's more common to have /usr/local/bin ahead of /usr/bin, and it may be what you actually want—but if you have it the other way around, presumably there's a good reason for that.)

But you don't need to change your default Python to get the system to run 2.7 when you type python.

First, you can set up a shell alias:

alias python=/usr/local/bin/python2.7

Type that at a prompt, or put it in your ~/.bashrc if you want the change to be persistent, and now when you type python it runs your chosen 2.7, but when some program on your system tries to run a script with /usr/bin/env python it runs the standard 2.6.

Alternatively, just create a virtual environment out of your 2.7 (or separate venvs for different projects), and do your work inside the venv.

SSL InsecurePlatform error when using Requests package

Below is how it's working for me on Python 3.6:

import requests
import urllib3

# Suppress InsecureRequestWarning: Unverified HTTPS

Awk if else issues

Try the code

awk '{s=($3==0)?"-":$3/$4; print s}'

endsWith in JavaScript

all of them are very useful examples. Adding String.prototype.endsWith = function(str) will help us to simply call the method to check if our string ends with it or not, well regexp will also do it.

I found a better solution than mine. Thanks every one.

How to scroll to bottom in a ScrollView on activity startup

 scrollView.postDelayed(new Runnable() {
        public void run() {

How do I pass a variable by reference?

You can merely use an empty class as an instance to store reference objects because internally object attributes are stored in an instance dictionary. See the example.

class RefsObj(object):
    "A class which helps to create references to variables."


# an example of usage
def change_ref_var(ref_obj):
    ref_obj.val = 24

ref_obj = RefsObj()
ref_obj.val = 1
print(ref_obj.val) # or print ref_obj.val for python2

Get type name without full namespace

make use of (Type Properties)

 Name   Gets the name of the current member. (Inherited from MemberInfo.)
 Example : typeof(T).Name;

SQL Server CASE .. WHEN .. IN statement

CASE AlarmEventTransactions.DeviceID should just be CASE.

You are mixing the 2 forms of the CASE expression.

PHPmailer sending HTML CODE

do like this-paste your html code inside your separate html file using GET method.

    $mail->WordWrap = 70;                                 
    $mail->addAttachment= $_GET['addattachment']; $mail->AltBody   
    =$_GET['AltBody'];  $mail->Subject = $_GET['subject']; $mail->Body = $_GET['body'];

How do I remove link underlining in my HTML email?

All you have to do is:

<a href="" style="text-decoration:#none; letter-spacing: -999px;">

Rename a dictionary key

A few people before me mentioned the .pop trick to delete and create a key in a one-liner.

I personally find the more explicit implementation more readable:

d = {'a': 1, 'b': 2}
v = d['b']
del d['b']
d['c'] = v

The code above returns {'a': 1, 'c': 2}

Get list of certificates from the certificate store in C#

The simplest way to do that is by opening the certificate store you want and then using X509Certificate2UI.

var store = new X509Store(StoreName.My, StoreLocation.LocalMachine);
var selectedCertificate = X509Certificate2UI.SelectFromCollection(

More information in X509Certificate2UI on MSDN.

how to check if a datareader is null or empty

In addition to the suggestions given, you can do this directly from your query like this -

SELECT ISNULL([Additional], -1) AS [Additional]

This way you can write the condition to check whether the field value is < 0 or >= 0.

Autoplay audio files on an iPad with HTML5

Apple annoyingly rejects many HTML5 web standards on their iOS devices, for a variety of business reasons. Ultimately, you can't pre-load or auto-play sound files before a touch event, it only plays one sound at a time, and it doesn't support Ogg/Vorbis. However, I did find one nifty workaround to let you have a little more control over the audio.

<audio id="soundHandle" style="display:none;"></audio>

<script type="text/javascript">

var soundHandle = document.getElementById('soundHandle');

$(document).ready(function() {
    addEventListener('touchstart', function (e) {
        soundHandle.src = 'audio.mp3';
        soundHandle.loop = true;;


Basically, you start playing the audio file on the very first touch event, then you pause it immediately. Now, you can use the and soundHandle.pause() commands throughout your Javascript and control the audio without touch events. If you can time it perfectly, just have the pause come in right after the sound is over. Then next time you play it again, it will loop back to the beginning. This won't resolve all the mess Apple has made here, but it's one solution.

fork() and wait() with two child processes

brilliant example Jonathan Leffler, to make your code work on SLES, I needed to add an additional header to allow the pid_t object :)

#include <sys/types.h>

Disable submit button on form submit

Simple and effective solution is

<form ... onsubmit="myButton.disabled = true; return true;">
    <input type="submit" name="myButton" value="Submit">

Source: here

sql server Get the FULL month name from a date

If you are using SQL Server 2012 or later, you can use:

SELECT FORMAT(MyDate, 'MMMM dd yyyy')

You can view the documentation for more information on the format.

Revert to Eclipse default settings

Deleting everything under your workspace's .metadata\.plugins\org.eclipse.core.runtime\.settings will restore to defaults but you will lose every other setting too. You can selectively undo changes made by importing RainbowDrops.epf

Open RanbowDrops.epf. Mine looks like this





the lines starting with /instance/ccw.core will go into file ccw.core.prefs. Lines instance/ will go into and so on. You need to delete those files only. There are quite a lot of them though (i had to delete 53), easy way to sift them is to find the first one and sort by modification time they will group together.

BTW there is nice dark theme available by default in eclipse 4.7 (2017). You can try and switch color themes without this kind of hassle by installing Eclipse Color Themes plugin, it also has good selection of dark color themes too.

Collision resolution in Java HashMap

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

How to make RatingBar to show five stars

            android:isIndicator="true" />

in code


Should you always favor xrange() over range()?

You should favour range() over xrange() only when you need an actual list. For instance, when you want to modify the list returned by range(), or when you wish to slice it. For iteration or even just normal indexing, xrange() will work fine (and usually much more efficiently). There is a point where range() is a bit faster than xrange() for very small lists, but depending on your hardware and various other details, the break-even can be at a result of length 1 or 2; not something to worry about. Prefer xrange(). - Add blank item at top of dropdownlist

After your databind:

drpList.Items.Insert(0, new ListItem(String.Empty, String.Empty));
drpList.SelectedIndex = 0;

Clear the value of bootstrap-datepicker

I was having similar trouble and the following worked for me:


Both method calls were needed, otherwise it didn't clear.

How to monitor Java memory usage?

JavaMelody might be a solution for your need.

Developed for Java EE applications, this tool measure and build report about the real operation of your applications on any environments. It's free and open-source and easy to integrate into applications with some history, no database nor profiling, really lightweight.

yii2 hidden input value

Hello World!
You see, the main question while using hidden input is what kind of data you want to pass? I will assume that you are trying to pass the user ID.
Which is not a really good idea to pass it here because field() method will generate input and the value will be shown to user as we can't hide html from the users browser. This if you really care about security of your website.

please check this link, and you will see that it's impossible to hide value attribute from users to see.

so what to do then?

See, this is the core of OOP in PHP. and I quote from Matt Zandstr in his great book PHP Objects, Patterns, and Practice fifth edition

I am still stuck with a great deal of unwanted flexibility, though. I rely on the client coder to change a ShopProduct object’s properties from their default values. This is problematic in two ways. First, it takes five lines to properly initialize a ShopProduct object, and no coder will thank you for that. Second, I have no way of ensuring that any of the properties are set when a ShopProduct object is initialized. What I need is a method that is called automatically when an object is instantiated from a class.

Please check this example of using __construct() method which is mentioned in his book too.

     class ShopProduct { 
       public $title;   
       public $producerMainName;  
       public $producerFirstName;  
       public $price = 0;
       public function __construct($title,$firstName,$mainName,$price) {
            $this->title = $title;
            $this->producerFirstName = $firstName;  
            $this->producerMainName = $mainName; 
            $this->price = $price;

And you can simply do this magic.

$product1 = new ShopProduct("My Antonia","Willa","Cather",5.99 );
print "author: {$product1->getProducer()}\n";

This produces the following:

author: Willa Cather

In your case it will be something semilar to this, every time you create an object just pass the user ID to the user_id property, and save yourself a lot of coding.

Class Car {
  private $user_id;
//.. your properties

  public function __construct($title,$firstName,$mainName,$price){
     $this->user_id = \Yii::$app->user->id;
    //..Your magic


Good luck! And Happy Coding!

Getting the first index of an object

If the order of the objects is significant, you should revise your JSON schema to store the objects in an array:

    {"name":"foo", ...},
    {"name":"bar", ...},
    {"name":"baz", ...}

or maybe:

    ["foo", {}],
    ["bar", {}],
    ["baz", {}]

As Ben Alpert points out, properties of Javascript objects are unordered, and your code is broken if you expect them to enumerate in the same order that they are specified in the object literal—there is no "first" property.

How to detect browser using angularjs?

Detection ie9+

var userAgent, ieReg, ie;
  userAgent = $window.navigator.userAgent;
  ieReg = /msie|Trident.*rv[ :]*11\./gi;
  ie = ieReg.test(userAgent);

if (ie) {
   // js for ie9,10 and 11

How can I submit a form using JavaScript?


<!-- change id attribute to name  -->

<form method="post" action="yourUrl" name="theForm">
    <button onclick="placeOrder()">Place Order</button>


function placeOrder () {

Removing leading zeroes from a field in a SQL statement

Here is the SQL scalar value function that removes leading zeros from string:

-- =============================================
-- Author:      Vikas Patel
-- Create date: 01/31/2019
-- Description: Remove leading zeros from string
-- =============================================
CREATE FUNCTION dbo.funRemoveLeadingZeros 
    -- Add the parameters for the function here
    @Input varchar(max)
RETURNS varchar(max)
    -- Declare the return variable here
    DECLARE @Result varchar(max)

    -- Add the T-SQL statements to compute the return value here
    SET @Result = @Input

    WHILE LEFT(@Result, 1) = '0'
        SET @Result = SUBSTRING(@Result, 2, LEN(@Result) - 1)

    -- Return the result of the function
    RETURN @Result


POST string to ASP.NET Web Api application - returns null

You seem to have used some [Authorize] attribute on your Web API controller action and I don't see how this is relevant to your question.

So, let's get into practice. Here's a how a trivial Web API controller might look like:

public class TestController : ApiController
    public string Post([FromBody] string value)
        return value;

and a consumer for that matter:

class Program
    static void Main()
        using (var client = new WebClient())
            client.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
            var data = "=Short test...";
            var result = client.UploadString("http://localhost:52996/api/test", "POST", data);

You will undoubtedly notice the [FromBody] decoration of the Web API controller attribute as well as the = prefix of the POST data om the client side. I would recommend you reading about how does the Web API does parameter binding to better understand the concepts.

As far as the [Authorize] attribute is concerned, this could be used to protect some actions on your server from being accessible only to authenticated users. Actually it is pretty unclear what you are trying to achieve here.You should have made this more clear in your question by the way. Are you are trying to understand how parameter bind works in ASP.NET Web API (please read the article I've linked to if this is your goal) or are attempting to do some authentication and/or authorization? If the second is your case you might find the following post that I wrote on this topic interesting to get you started.

And if after reading the materials I've linked to, you are like me and say to yourself, WTF man, all I need to do is POST a string to a server side endpoint and I need to do all of this? No way. Then checkout ServiceStack. You will have a good base for comparison with Web API. I don't know what the dudes at Microsoft were thinking about when designing the Web API, but come on, seriously, we should have separate base controllers for our HTML (think Razor) and REST stuff? This cannot be serious.

How to pass complex object to ASP.NET WebApi GET from jQuery ajax call?

After finding this StackOverflow question/answer

Complex type is getting null in a ApiController parameter

the [FromBody] attribute on the controller method needs to be [FromUri] since a GET does not have a body. After this change the "filter" complex object is passed correctly.

MySql Proccesslist filled with "Sleep" Entries leading to "Too many Connections"?

The above solutions like run a query

SET session wait_timeout=600;

Will only work until mysql is restarted. For a persistant solution, edit mysql.conf and add after [mysqld]:

interactive_timeout = 300

Where 300 is the number of seconds you want.

Align labels in form next to input

You can do something like this:


<div class='div'>
<input type='text' class='input'/>


      margin-bottom: 10px;
      display: grid;
      grid-template-columns: 1fr 4fr;

       width: 50%;

Hope this helps ! :)

Log4net rolling daily filename with date in the file name

The extended configuration section in a previous response with

 <rollingStyle value="Composite" />

listed works but I did not have to use

<staticLogFileName value="false" /> 

. I think the RollingAppender must (logically) ignore that setting since by definition the file gets rebuilt each day when the application restarts/reused. Perhaps it does matter for immediate rollover EVERY time the application starts.

Why is there no tuple comprehension in Python?

Parentheses do not create a tuple. aka one = (two) is not a tuple. The only way around is either one = (two,) or one = tuple(two). So a solution is:

tuple(i for i in myothertupleorlistordict) 

Auto-click button element on page load using jQuery

You would simply use jQuery like so...


Use the click function to auto-click the #modal button

Set start value for column with autoincrement

In the Table Designer on SQL Server Management Studio you can set the where the auto increment will start. Right-click on the table in Object Explorer and choose Design, then go to the Column Properties for the relevant column:

Here the autoincrement will start at 760

What do I use on linux to make a python program executable

If one want to make executable

first find the path where python is in your os with : which python

it usually resides under "/usr/bin/python" folder.

at the very first line of one should add : #!/usr/bin/python

then through linux command chmod

one should just make it executable like : chmod +x

and execute with ./

Get Wordpress Category from Single Post

For the lazy and the learning, to put it into your theme, Rfvgyhn's full code

<?php $category = get_the_category();
$firstCategory = $category[0]->cat_name; echo $firstCategory;?>

How to create a JPA query with LEFT OUTER JOIN

Write this;

 SELECT f from Student f LEFT JOIN f.classTbls s WHERE s.ClassName = 'abc'

Because your Student entity has One To Many relationship with ClassTbl entity.

How to get a value of an element by name instead of ID

To get the value, we can use multiple attributes, one of them being the name attribute. E.g


We can also use other attributes to get values


<input type="text" id="demoText" demo="textValue" />



How can I import a large (14 GB) MySQL dump file into a new MySQL database?

Have you tried just using the mysql command line client directly?

mysql -u username -p -h hostname databasename < dump.sql

If you can't do that, there are any number of utilities you can find by Googling that help you import a large dump into MySQL, like BigDump

How to update /etc/hosts file in Docker image during "docker build"

Complete Answer

  1. Prepare your own hosts file you wish to add to docker container;
  1. COPY your hosts file into the container by adding the following line in the Dockerfile
COPY hosts /etc/hosts_extra
  1. If you know how to use ENTRYPOINT or CMD or CRON job then incorporate the following command line into it or at least run this inside the running container:
cat /etc/hosts_extra >> etc/hosts;
  1. You cannot add the following in the Dockerfile because the modification will be lost:
RUN cat /etc/hosts_extra >> etc/hosts;

How to map atan2() to degrees 0-360

An alternative solution is to use the mod () function defined as:

function mod(a, b) {return a - Math.floor (a / b) * b;}

Then, with the following function, the angle between ini(x,y) and end(x,y) points is obtained. The angle is expressed in degrees normalized to [0, 360] deg. and North referencing 360 deg.

    function angleInDegrees(ini, end) {
        var radian = Math.atan2((end.y - ini.y), (end.x - ini.x));//radian [-PI,PI]
        return mod(radian * 180 / Math.PI + 90, 360);

Generate war file from tomcat webapp folder

Create the war file in a different directory to where the content is otherwise the jar command might try to zip up the file it is creating.


set -euo pipefail


# Clean last war build
if [ -e ${war} ]; then
    echo "Removing old war ${war}"
    rm -rf ${war}

# Build war
if [ -d ${src} ]; then
    echo "Found source at ${src}"
    cd ${src}
    jar -cvf ../${war} *
    cd ..

# Show war details
ls -la ${war}