Programs & Examples On #User identification

Get value of a specific object property in C# without knowing the class behind

You can do it using dynamic instead of object:

dynamic item = AnyFunction(....);
string value =;

Note that the Dynamic Language Runtime (DLR) has built-in caching mechanisms, so subsequent calls are very fast.

How do you pass a function as a parameter in C?


A prototype for a function which takes a function parameter looks like the following:

void func ( void (*f)(int) );

This states that the parameter f will be a pointer to a function which has a void return type and which takes a single int parameter. The following function (print) is an example of a function which could be passed to func as a parameter because it is the proper type:

void print ( int x ) {
  printf("%d\n", x);

Function Call

When calling a function with a function parameter, the value passed must be a pointer to a function. Use the function's name (without parentheses) for this:


would call func, passing the print function to it.

Function Body

As with any parameter, func can now use the parameter's name in the function body to access the value of the parameter. Let's say that func will apply the function it is passed to the numbers 0-4. Consider, first, what the loop would look like to call print directly:

for ( int ctr = 0 ; ctr < 5 ; ctr++ ) {

Since func's parameter declaration says that f is the name for a pointer to the desired function, we recall first that if f is a pointer then *f is the thing that f points to (i.e. the function print in this case). As a result, just replace every occurrence of print in the loop above with *f:

void func ( void (*f)(int) ) {
  for ( int ctr = 0 ; ctr < 5 ; ctr++ ) {


Conditional replacement of values in a data.frame

Since you are conditionally indexing df$est, you also need to conditionally index the replacement vector df$a:

index <- df$b == 0
df$est[index] <- (df$a[index] - 5)/2.533 

Of course, the variable index is just temporary, and I use it to make the code a bit more readible. You can write it in one step:

df$est[df$b == 0] <- (df$a[df$b == 0] - 5)/2.533 

For even better readibility, you can use within:

df <- within(df, est[b==0] <- (a[b==0]-5)/2.533)

The results, regardless of which method you choose:

          a b      est
1  11.77000 2 0.000000
2  10.90000 3 0.000000
3  10.32000 2 0.000000
4  10.96000 0 2.352941
5   9.90600 0 1.936834
6  10.70000 0 2.250296
7  11.43000 1 0.000000
8  11.41000 2 0.000000
9  10.48512 4 0.000000
10 11.19000 0 2.443743

As others have pointed out, an alternative solution in your example is to use ifelse.

Can we execute a java program without a main() method?

You should also be able to accomplish a similar thing using the premain method of a Java agent.

The manifest of the agent JAR file must contain the attribute Premain-Class. The value of this attribute is the name of the agent class. The agent class must implement a public static premain method similar in principle to the main application entry point. After the Java Virtual Machine (JVM) has initialized, each premain method will be called in the order the agents were specified, then the real application main method will be called. Each premain method must return in order for the startup sequence to proceed.

git error: failed to push some refs to remote

Best use rm -rf .git/hooks and then try git push

Android studio, gradle and NDK

We have released a first version of the integration as a preview in 1.3:

The integration will stay a preview even after 1.3 becomes final. No current ETA as to when it'll be final (as of 2015/07/10).

More information here:

removing html element styles via javascript

In JavaScript:

document.getElementById("id").style.display = null;

In jQuery:


How to check "hasRole" in Java Code with Spring Security?

You can retrieve the security context and then use that:


    protected boolean hasRole(String role) {
        // get security context from thread local
        SecurityContext context = SecurityContextHolder.getContext();
        if (context == null)
            return false;

        Authentication authentication = context.getAuthentication();
        if (authentication == null)
            return false;

        for (GrantedAuthority auth : authentication.getAuthorities()) {
            if (role.equals(auth.getAuthority()))
                return true;

        return false;

How do I call an Angular 2 pipe with multiple arguments?

I use Pipes in Angular 2+ to filter arrays of objects. The following takes multiple filter arguments but you can send just one if that suits your needs. Here is a StackBlitz Example. It will find the keys you want to filter by and then filters by the value you supply. It's actually quite simple, if it sounds complicated it's not, check out the StackBlitz Example.

Here is the Pipe being called in an *ngFor directive,

<div *ngFor='let item of items | filtermulti: [{title:"mr"},{last:"jacobs"}]' >
  Hello {{item.first}} !

Here is the Pipe,

import { Pipe, PipeTransform } from '@angular/core';

  name: 'filtermulti'
export class FiltermultiPipe implements PipeTransform {
  transform(myobjects: Array<object>, args?: Array<object>): any {
    if (args && Array.isArray(myobjects)) {
      // copy all objects of original array into new array of objects
      var returnobjects = myobjects;
      // args are the compare oprators provided in the *ngFor directive
      args.forEach(function (filterobj) {
        let filterkey = Object.keys(filterobj)[0];
        let filtervalue = filterobj[filterkey];
        myobjects.forEach(function (objectToFilter) {
          if (objectToFilter[filterkey] != filtervalue && filtervalue != "") {
            // object didn't match a filter value so remove it from array via filter
            returnobjects = returnobjects.filter(obj => obj !== objectToFilter);
      // return new array of objects to *ngFor directive
      return returnobjects;

And here is the Component containing the object to filter,

import { Component } from '@angular/core';
import { FiltermultiPipe } from './pipes/filtermulti.pipe';

  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
export class AppComponent {
  title = 'app';
  items = [{ title: "mr", first: "john", last: "jones" }
   ,{ title: "mr", first: "adrian", last: "jacobs" }
   ,{ title: "mr", first: "lou", last: "jones" }
   ,{ title: "ms", first: "linda", last: "hamilton" }

StackBlitz Example

GitHub Example: Fork a working copy of this example here

*Please note that in an answer provided by Gunter, Gunter states that arrays are no longer used as filter interfaces but I searched the link he provides and found nothing speaking to that claim. Also, the StackBlitz example provided shows this code working as intended in Angular 6.1.9. It will work in Angular 2+.

Happy Coding :-)

Add CSS class to a div in code behind

<div runat="server"> is mapped to a HtmlGenericControl. Try using BtnventCss.Attributes.Add("class", "hom_but_a");

Using FileSystemWatcher to monitor a directory

The reason may be that watcher is declared as local variable to a method and it is garbage collected when the method finishes. You should declare it as a class member. Try the following:

FileSystemWatcher watcher;

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

private void OnChanged(object source, FileSystemEventArgs e)
  //Copies file to another directory.

jQuery function after .append

I came across the same problem and have found a simple solution. Add after calling the append function a document ready.

$(document).ready(function () {_x000D_
    // Action after append is completly done_x000D_

how to select rows based on distinct values of A COLUMN only

use this(assume that your table name is emails):

select * from emails as a 
inner join  
(select EmailAddress, min(Id) as id from emails 
group by EmailAddress ) as b 
on a.EmailAddress = b.EmailAddress 
and a.Id =

hope this help.. with target "_blank" in Chrome

You can't do it because you can't have control on the manner Chrome opens its windows

Your password does not satisfy the current policy requirements

mysql> SET GLOBAL validate_password.policy = 0;

Is there a JSON equivalent of XQuery/XPath?

Yup, it's called JSONPath:

It's also integrated into DOJO.

How to ignore conflicts in rpm installs

Try Freshen command:

rpm -Fvh *.rpm

Determine project root from a running node.js application


Export data from R to Excel

writexl, without Java requirement:

# install.packages("writexl")
tempfile <- write_xlsx(iris)

How to analyse the heap dump using jmap in java

Very late to answer this, but worth to take a quick look at. Just 2 minutes needed to understand in detail.

First create this java program

import java.util.ArrayList;
import java.util.List;

public class GarbageCollectionAnalysisExample{
    public static void main(String[] args) {
           List<String> l = new ArrayList<String>();
           for (int i = 0; i < 100000000; i++) {
                  l = new ArrayList<String>(); //Memory leak

Use jps to find the vmid (virtual machine id i.e. JVM id)

Go to CMD and type below commands >

18588 Jps
17252 GarbageCollectionAnalysisExample
2084 Main

17252 is the vmid which we need.

Now we will learn how to use jmap and jhat

Use jmap - to generate heap dump

From java docs about jmap “jmap prints shared object memory maps or heap memory details of a given process or core file or a remote debug server”

Use following command to generate heap dump >

C:\>jmap -dump:file=E:\heapDump.jmap 17252
Dumping heap to E:\heapDump.jmap ...
Heap dump file created

Where 17252 is the vmid (picked from above).

Heap dump will be generated in E:\heapDump.jmap

Now use Jhat Jhat is used for analyzing the garbage collection dump in java -

C:\>jhat E:\heapDump.jmap
Reading from E:\heapDump.jmap...
Dump file created Mon Nov 07 23:59:19 IST 2016
Snapshot read, resolving...
Resolving 241865 objects...
Chasing references, expect 48 dots................................................
Eliminating duplicate references................................................
Snapshot resolved.
Started HTTP server on port 7000
Server is ready.

By default, it will start http server on port 7000. Then we will go to http://localhost:7000/

Courtesy : JMAP, How to monitor and analyze the garbage collection in 10 ways

How to fix Uncaught InvalidValueError: setPosition: not a LatLng or LatLngLiteral: in property lat: not a number?

You're probably passing null value if you're loading the coordinates dynamically, set a check before you call the map loader ie: if(mapCords){loadMap}

What is the difference between document.location.href and document.location?

document.location is an object, while document.location.href is a string. But the former has a toString method, so you can read from it as if it was a string and get the same value as document.location.href.

In some browsers - most modern ones, I think - you can also assign to document.location as if it were a string. According to the Mozilla documentation however, it is better to use window.location for this purpose as document.location was originally read-only and so may not be as widely supported.

Modify XML existing content in C#

Using LINQ to xml if you are using framework 3.5

using System.Xml.Linq;

XDocument xmlFile = XDocument.Load("books.xml"); 
var query = from c in xmlFile.Elements("catalog").Elements("book")    
            select c; 
foreach (XElement book in query) 
    book.Attribute("attr1").Value = "MyNewValue";

mysql query: SELECT DISTINCT column1, GROUP BY column2

Somehow your requirement sounds a bit contradictory ..

group by name (which is basically a distinct on name plus readiness to aggregate) and then a distinct on IP

What do you think should happen if two people (names) worked from the same IP within the time period specified?

Did you try this?

SELECT name, COUNT(name), time, price, ip, SUM(price) 
  FROM tablename 
 WHERE time >= $yesterday AND time <$today 
GROUP BY name,ip

RESTful URL design for search

For the searching, use querystrings. This is perfectly RESTful:


An advantage to regular querystrings is that they are standard and widely understood and that they can be generated from form-get.

How to declare 2D array in bash

For simulating a 2-dimensional array, I first load the first n-elements (the elements of the first column)

local pano_array=()  


for line in $(grep  "filename" "$file")
  url=$(extract_url_from_xml $line)

To add the second column, I define the size of the first column and calculate the values in an offset variable



while [[ $i -lt $array_len ]]
  found_file=$(get_file $url)


What do *args and **kwargs mean?

Putting *args and/or **kwargs as the last items in your function definition’s argument list allows that function to accept an arbitrary number of arguments and/or keyword arguments.

For example, if you wanted to write a function that returned the sum of all its arguments, no matter how many you supply, you could write it like this:

def my_sum(*args):
    return sum(args)

It’s probably more commonly used in object-oriented programming, when you’re overriding a function, and want to call the original function with whatever arguments the user passes in.

You don’t actually have to call them args and kwargs, that’s just a convention. It’s the * and ** that do the magic.

The official Python documentation has a more in-depth look.

Codeigniter $this->db->get(), how do I return values for a specific row?

Incase you are dynamically getting your data e.g When you need data based on the user logged in by their id use consider the following code example for a No Active Record:

 $this->db->query('SELECT * FROM my_users_table WHERE id = ?', $this->session->userdata('id'));

 return $query->row_array();

This will return a specific row based on your the set session data of user.

Determine a string's encoding in C#

My finally working approach is to try potential candidates of expected encodings by detecting invalid characters in the strings created from the byte array by the encodings. If I don't encounter invalid characters, I suppose the tested encoding works fine for the tested data.

For me, having only Latin and German special characters to consider, in order to determine the proper encoding for a byte array, I try to detect invalid characters in a string with this method:

    /// <summary>
    /// detect invalid characters in string, use to detect improper encoding
    /// </summary>
    /// <param name="s"></param>
    /// <returns></returns>
    public static bool DetectInvalidChars(string s)
        const string specialChars = "\r\n\t .,;:-_!\"'?()[]{}&%$§=*+~#@|<>äöüÄÖÜß/\\^€";
        return s.Any(ch => !(
            specialChars.Contains(ch) ||
            (ch >= '0' && ch <= '9') ||
            (ch >= 'a' && ch <= 'z') ||
            (ch >= 'A' && ch <= 'Z')));

(NB: if you have other Latin-based languages to consider, you might want to adapt the specialChars const string in the code)

Then I use it like this (I only expect UTF-8 or Default encoding):

        // determine encoding by detecting invalid characters in string
        var invoiceXmlText = Encoding.UTF8.GetString(invoiceXmlBytes); // try utf-8 first
        if (StringFuncs.DetectInvalidChars(invoiceXmlText))
            invoiceXmlText = Encoding.Default.GetString(invoiceXmlBytes); // fallback to default

show and hide divs based on radio button click

You're on the right track, but you forgot two things:

  1. add the desc classes to your description divs
  2. You have numeric values for the input but text for the id.

I have fixed the above and also added a line to initially hide() the third description div.

Check it out in action -


<div id="myRadioGroup">
    2 Cars<input type="radio" name="cars" checked="checked" value="2"  />
    3 Cars<input type="radio" name="cars" value="3" />

    <div id="Cars2" class="desc">
        2 Cars Selected
    <div id="Cars3" class="desc" style="display: none;">
        3 Cars


$(document).ready(function() {
    $("input[name$='cars']").click(function() {
        var test = $(this).val();

        $("#Cars" + test).show();

Is it possible to declare two variables of different types in a for loop?

No - but technically there is a work-around (not that i'd actually use it unless forced to):

for(struct { int a; char b; } s = { 0, 'a' } ; s.a < 5 ; ++s.a) 
    std::cout << s.a << " " << s.b << std::endl;

How to get the path of src/test/resources directory in JUnit?

The simplest and clean solution I uses, suppose the name of the test class is TestQuery1 and there is a resources directory in your test folder as follows:

+-- java
¦   +--
+-- resources
    +-- TestQuery1
        +-- query.json
        +-- query.rq

To get the URI of TestQuery1 do:

URL currentTestResourceFolder = getClass().getResource("/"+getClass().getSimpleName());

To get the URI of one of the file TestQuery1, do:

File exampleDir = new File(currentTestResourceFolder.toURI());
URI queryJSONFileURI = exampleDir.toURI().resolve("query.json");

How can I add an ampersand for a value in a app config file value

Have you tried this?

  <add key="myurl" value=";cid=&amp;sid="/>

Parse an URL in JavaScript

Web Workers provide an utils URL for url parsing.

Kill a Process by Looking up the Port being used by it from a .BAT

Paste this into command line

FOR /F "tokens=5 delims= " %P IN ('netstat -ano ^| find "LISTENING" ^| find ":8080 "') DO (TASKKILL /PID %P)

If you want to use it in a batch pu %%P instead of %P

React.js, wait for setState to finish before triggering a function?

According to the docs of setState() the new state might not get reflected in the callback function findRoutes(). Here is the extract from React docs:

setState() does not immediately mutate this.state but creates a pending state transition. Accessing this.state after calling this method can potentially return the existing value.

There is no guarantee of synchronous operation of calls to setState and calls may be batched for performance gains.

So here is what I propose you should do. You should pass the new states input in the callback function findRoutes().

handleFormSubmit: function(input){
    // Form Input
        originId: input.originId,
        destinationId: input.destinationId,
        radius: input.radius,
    this.findRoutes(input);    // Pass the input here

The findRoutes() function should be defined like this:

findRoutes: function(me = this.state) {    // This will accept the input if passed otherwise use this.state
    if (!me.originId || !me.destinationId) {
    var p1 = new Promise(function(resolve, reject) {
            origin: {'placeId': me.originId},
            destination: {'placeId': me.destinationId},
            travelMode: me.travelMode
        }, function(response, status){
            if (status === google.maps.DirectionsStatus.OK) {
                // me.response = response;
            } else {
                window.alert('Directions config failed due to ' + status);
    return p1

Error: JAVA_HOME is not defined correctly executing maven

Use these two commands (for Java 8):

sudo update-java-alternatives --set java-8-oracle
java -XshowSettings 2>&1 | grep -e 'java.home' | awk '{print "JAVA_HOME="$3}' | sed "s/\/jre//g" >> /etc/environment

correct quoting for cmd.exe for multiple arguments

Spaces are horrible in filenames or directory names.

The correct syntax for this is to include every directory name that includes spaces, in double quotes

cmd /c C:\"Program Files"\"Microsoft Visual Studio 9.0"\Common7\IDE\ mysolution.sln /build "release|win32"

Why use Gradle instead of Ant or Maven?

This isn't my answer, but it definitely resonates with me. It's from ThoughtWorks' Technology Radar from October 2012:

Two things have caused fatigue with XML-based build tools like Ant and Maven: too many angry pointy braces and the coarseness of plug-in architectures. While syntax issues can be dealt with through generation, plug-in architectures severely limit the ability for build tools to grow gracefully as projects become more complex. We have come to feel that plug-ins are the wrong level of abstraction, and prefer language-based tools like Gradle and Rake instead, because they offer finer-grained abstractions and more flexibility long term.

React Native: Getting the position of an element

If you use function components and don't want to use a forwardRef to measure your component's absolute layout, you can get a reference to it from the LayoutChangeEvent in the onLayout callback.

This way, you can get the absolute position of the element:

  onLayout={(event) => {
      (x, y, width, height, pageX, pageX) => {
          x: x + pageX, 
          y: y + pageY,

Tested with React Native 0.63.3.

How to reset or change the passphrase for a GitHub SSH key?

You can change the passphrase for your private key by doing:

ssh-keygen -f ~/.ssh/id_rsa -p

SQLSTATE[42S22]: Column not found: 1054 Unknown column - Laravel

You have configured the auth.php and used members table for authentication but there is no user_email field in the members table so, Laravel says

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'user_email' in 'where clause' (SQL: select * from members where user_email = ? limit 1) (Bindings: array ( 0 => '[email protected]', ))

Because, it tries to match the user_email in the members table and it's not there. According to your auth configuration, laravel is using members table for authentication not users table.

How do I store the select column in a variable?

Assuming such a query would return a single row, you could use either

select @EmpId = Id from dbo.Employee


set @EmpId = (select Id from dbo.Employee)

Setting the User-Agent header for a WebClient request

As a supplement to the other answers, here is Microsoft's guidance for user agent strings for its browsers. The user agent strings differ by browser (Internet Explorer and Edge) and operating system (Windows 7, 8, 10 and Windows Phone).

For example, here is the user agent string for Internet Explorer 11 on Windows 10:

Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko 

and for Internet Explorer for Windows Phone 8.1 Update:

Mozilla/5.0 (Mobile; Windows Phone 8.1; Android 4.0; ARM; Trident/7.0; Touch; rv:11.0; IEMobile/11.0; NOKIA; Lumia 520) like iPhone OS 7_0_3 Mac OS X AppleWebKit/537 (KHTML, like Gecko) Mobile Safari/537

Templates are given for the user agent strings for the Edge browser for Desktop, Mobile and WebView. See this answer for some Edge user agent string examples.

Finally, another page on MSDN provides guidance for IE11 on older desktop operating systems.

IE11 on Windows 8.1:

Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko

and IE11 on Windows 7:

Mozilla/5.0 (Windows NT 6.1; Trident/7.0; rv:11.0) like Gecko

How can I add an element after another element?





Can I have H2 autocreate a schema in an in-memory database?

If you are using spring with application.yml the following will work for you

spring: datasource: url: jdbc:h2:mem:mydb;DB_CLOSE_ON_EXIT=FALSE;MODE=PostgreSQL;INIT=CREATE SCHEMA IF NOT EXISTS calendar

How can I get the full/absolute URL (with domain) in Django?

You can either pass request reverse('view-name', request=request) or enclose reverse() with build_absolute_uri request.build_absolute_uri(reverse('view-name'))

How to set thousands separator in Java?

The accepted answer has to be really altered otherwise not working. The getDecimalFormatSymbols makes a defensive copy. Thus,

DecimalFormat formatter = (DecimalFormat) NumberFormat.getInstance(Locale.US);
DecimalFormatSymbols symbols = formatter.getDecimalFormatSymbols();

symbols.setGroupingSeparator(' ');

The new line is this one: formatter.setDecimalFormatSymbols(symbols);

How can I SELECT rows with MAX(Column value), DISTINCT by another column in SQL?

@Michae The accepted answer will working fine in most of the cases but it fail for one for as below.

In case if there were 2 rows having HomeID and Datetime same the query will return both rows, not distinct HomeID as required, for that add Distinct in query as below.

SELECT DISTINCT tt.home  , tt.MaxDateTime
FROM topten tt
    (SELECT home, MAX(datetime) AS MaxDateTime
    FROM topten
    GROUP BY home) groupedtt 
ON tt.home = groupedtt.home 
AND tt.datetime = groupedtt.MaxDateTime

Instantiating a generic type

You basically have two choices:

1.Require an instance:

public Navigation(T t) {     this("", "", t); } 

2.Require a class instance:

public Navigation(Class<T> c) {     this("", "", c.newInstance()); } 

You could use a factory pattern, but ultimately you'll face this same issue, but just push it elsewhere in the code.

How to repair a serialized string which has been corrupted by an incorrect byte count length?

unserialize() [function.unserialize]: Error at offset was dues to invalid serialization data due to invalid length

Quick Fix

What you can do is is recalculating the length of the elements in serialized array

You current serialized data

$data = 'a:10:{s:16:"submit_editorial";b:0;s:15:"submit_orig_url";s:13:"";s:12:"submit_title";s:14:"No title found";s:14:"submit_content";s:12:"dnfsdkfjdfdf";s:15:"submit_category";i:2;s:11:"submit_tags";s:3:"bbc";s:9:"submit_id";b:0;s:16:"submit_subscribe";i:0;s:15:"submit_comments";s:4:"open";s:5:"image";s:19:"C:fakepath100.jpg";}';

Example without recalculation



Notice: unserialize() [function.unserialize]: Error at offset 337 of 338 bytes


$data = preg_replace('!s:(\d+):"(.*?)";!e', "'s:'.strlen('$2').':\"$2\";'", $data);


  'submit_editorial' => boolean false
  'submit_orig_url' => string '' (length=13)
  'submit_title' => string 'No title found' (length=14)
  'submit_content' => string 'dnfsdkfjdfdf' (length=12)
  'submit_category' => int 2
  'submit_tags' => string 'bbc' (length=3)
  'submit_id' => boolean false
  'submit_subscribe' => int 0
  'submit_comments' => string 'open' (length=4)
  'image' => string 'C:fakepath100.jpg' (length=17)

Recommendation .. I

Instead of using this kind of quick fix ... i"ll advice you update the question with

  • How you are serializing your data

  • How you are Saving it ..

================================ EDIT 1 ===============================

The Error

The Error was generated because of use of double quote " instead single quote ' that is why C:\fakepath\100.png was converted to C:fakepath100.jpg

To fix the error

You need to change $h->vars['submitted_data'] From (Note the singe quite ' )


 $h->vars['submitted_data']['image'] = "C:\fakepath\100.png" ;


 $h->vars['submitted_data']['image'] = 'C:\fakepath\100.png' ;

Additional Filter

You can also add this simple filter before you call serialize

function satitize(&$value, $key)
    $value = addslashes($value);

array_walk($h->vars['submitted_data'], "satitize");

If you have UTF Characters you can also run

 $h->vars['submitted_data'] = array_map("utf8_encode",$h->vars['submitted_data']);

How to detect the problem in future serialized data

  findSerializeError ( $data1 ) ;


Diffrence 9 != 7
    -> ORD number 57 != 55
    -> Line Number = 315
    -> Section Data1  = pen";s:5:"image";s:19:"C:fakepath100.jpg
    -> Section Data2  = pen";s:5:"image";s:17:"C:fakepath100.jpg
                                            ^------- The Error (Element Length)

findSerializeError Function

function findSerializeError($data1) {
    echo "<pre>";
    $data2 = preg_replace ( '!s:(\d+):"(.*?)";!e', "'s:'.strlen('$2').':\"$2\";'",$data1 );
    $max = (strlen ( $data1 ) > strlen ( $data2 )) ? strlen ( $data1 ) : strlen ( $data2 );

    echo $data1 . PHP_EOL;
    echo $data2 . PHP_EOL;

    for($i = 0; $i < $max; $i ++) {

        if (@$data1 {$i} !== @$data2 {$i}) {

            echo "Diffrence ", @$data1 {$i}, " != ", @$data2 {$i}, PHP_EOL;
            echo "\t-> ORD number ", ord ( @$data1 {$i} ), " != ", ord ( @$data2 {$i} ), PHP_EOL;
            echo "\t-> Line Number = $i" . PHP_EOL;

            $start = ($i - 20);
            $start = ($start < 0) ? 0 : $start;
            $length = 40;

            $point = $max - $i;
            if ($point < 20) {
                $rlength = 1;
                $rpoint = - $point;
            } else {
                $rpoint = $length - 20;
                $rlength = 1;

            echo "\t-> Section Data1  = ", substr_replace ( substr ( $data1, $start, $length ), "<b style=\"color:green\">{$data1 {$i}}</b>", $rpoint, $rlength ), PHP_EOL;
            echo "\t-> Section Data2  = ", substr_replace ( substr ( $data2, $start, $length ), "<b style=\"color:red\">{$data2 {$i}}</b>", $rpoint, $rlength ), PHP_EOL;



A better way to save to Database

$toDatabse = base64_encode(serialize($data));  // Save to database
$fromDatabase = unserialize(base64_decode($data)); //Getting Save Format 

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

Here's a little php function I wrote that uses the regex directly from MSFT's suggested javascript sniffing code from this article:

* Returns the version of Internet Explorer or false
function isIE(){

    $isIE = preg_match("/MSIE ([0-9]{1,}[\.0-9]{0,})/",$_SERVER['HTTP_USER_AGENT'],$version);
        return $version[1];
    return $isIE;


Android Fragment onAttach() deprecated

public void onAttach(Context context) {

    Activity activity = context instanceof Activity ? (Activity) context : null;

How can I develop for iPhone using a Windows development machine?

The SDK is only available on OS X, forcing you to use a mac. If you don't want to purchase a mac you can either run OS X on a virtual machine on your windows box, or you can install OS X on your PC.

In my experience the virtual machine solution is unusably slow (on a core2 duo laptop with 2G ram). If you feel like trying it search for the torrent. It's probably not worthwhile.

The other option is to install OS X on your PC, commonly referred to as a hackintosh. Hackintoshes work quite well - my friend just sold his mac because his Dell quad core hackintosh was actually much faster than the apple hardware (and cost about 1/3). You can find lots of articles on how to do this; here's one on how to install on a Dell Inspirion 1525 laptop: hackbook pro tutorial

Of course both of these options are likely counter to some licensing scheme, so proceed at your own risk.

Check whether an array is empty

PHP's built-in empty() function checks to see whether the variable is empty, null, false, or a representation of zero. It doesn't return true just because the value associated with an array entry is false, in this case the array has actual elements in it and that's all that's evaluated.

If you'd like to check whether a particular error condition is set to true in an associative array, you can use the array_keys() function to filter the keys that have their value set to true.

$set_errors = array_keys( $errors, true );

You can then use the empty() function to check whether this array is empty, simultaneously telling you whether there are errors and also which errors have occurred.

Android Studio Google JAR file causing GC overhead limit exceeded error

I'm using Android Studio 3.4 and the only thing that worked for me was to remove the following lines from my build.gradle file:

minifyEnabled true
proguardFiles getDefaultProguardFile('proguard-android.txt'), ''

Because Android Studio 3.4 is using R8 in full mode and is not direct compatible with Proguard

Git - push current branch shortcut

According to git push documentation:

git push origin HEAD
    A handy way to push the current branch to the same name on the remote.

So I think what you need is git push origin HEAD. Also it can be useful git push -u origin HEAD to set upstream tracking information in the local branch, if you haven't already pushed to the origin.

Full screen background image in an activity

It's been a while since this was posted, but this helped me.

You can use nested layouts. Start with a RelativeLayout, and place your ImageView in that.

Set height and width to match_parent to fill the screen.

Set scaleType="centreCrop" so the image fits the screen and doesn't stretch.

Then you can put in any other layouts as you normally would, like the LinearLayout below.

You can use android:alpha to set the transparency of the image.






</RelativeLayout> no protocol

Try instead of db.parse(xml):

Document doc = db.parse(new InputSource(new StringReader(**xml**)));

How to define custom sort function in javascript?

For Objects try this:

function sortBy(field) {
  return function(a, b) {
    if (a[field] > b[field]) {
      return -1;
    } else if (a[field] < b[field]) {
      return 1;
    return 0;

How to delete/remove nodes on Firebase

Firebase.remove() like probably most Firebase methods is asynchronous, thus you have to listen to events to know when something happened:

parent = ref.parent()
parent.on('child_removed', function (snapshot) {
    // removed!

According to Firebase docs it should work even if you lose network connection. If you want to know when the change has been actually synchronized with Firebase servers, you can pass a callback function to Firebase.remove method:

ref.remove(function (error) {
    if (!error) {
        // removed!

Removing all unused references from a project in Visual Studio projects

For anybody coming here looking for Visual studio 2012:

Download and Install Reference Assistant for Visual Studio 11

Later you can do:

enter image description here

List all devices, partitions and volumes in Powershell

To get all of the file system drives, you can use the following command:

gdr -PSProvider 'FileSystem'

gdr is an alias for Get-PSDrive, which includes all of the "virtual drives" for the registry, etc.

Export DataTable to Excel File

This snippet could be faster to implement:

// Example data
DataTable table = new DataTable();
table.Columns.AddRange(new[]{ new DataColumn("Key"), new DataColumn("Value") });
foreach (string name in Request.ServerVariables)
    table.Rows.Add(name, Request.ServerVariables[name]);

// This actually makes your HTML output to be downloaded as .xls file
Response.ContentType = "application/octet-stream";
Response.AddHeader("Content-Disposition", "attachment; filename=ExcelFile.xls");

// Create a dynamic control, populate and render it
GridView excel = new GridView();
excel.DataSource = table;
excel.RenderControl(new HtmlTextWriter(Response.Output));


Java collections convert a string to a list of characters

You can do this without boxing if you use Eclipse Collections:

CharAdapter abc = Strings.asChars("abc");
CharList list = abc.toList();
CharSet set = abc.toSet();
CharBag bag = abc.toBag();

Because CharAdapter is an ImmutableCharList, calling collect on it will return an ImmutableList.

ImmutableList<Character> immutableList = abc.collect(Character::valueOf);

If you want to return a boxed List, Set or Bag of Character, the following will work:

LazyIterable<Character> lazyIterable = abc.asLazy().collect(Character::valueOf);
List<Character> list = lazyIterable.toList();
Set<Character> set = lazyIterable.toSet();
Bag<Character> set = lazyIterable.toBag();

Note: I am a committer for Eclipse Collections.

How to use timer in C?

May be this examples help to you

#include <stdio.h>
#include <time.h>
#include <stdlib.h>

    Implementation simple timeout

    Input: count milliseconds as number

        setTimeout(1000) - timeout on 1 second
        setTimeout(10100) - timeout on 10 seconds and 100 milliseconds
void setTimeout(int milliseconds)
    // If milliseconds is less or equal to 0
    // will be simple return from function without throw error
    if (milliseconds <= 0) {
        fprintf(stderr, "Count milliseconds for timeout is less or equal to 0\n");

    // a current time of milliseconds
    int milliseconds_since = clock() * 1000 / CLOCKS_PER_SEC;

    // needed count milliseconds of return from this timeout
    int end = milliseconds_since + milliseconds;

    // wait while until needed time comes
    do {
        milliseconds_since = clock() * 1000 / CLOCKS_PER_SEC;
    } while (milliseconds_since <= end);

int main()

    // input from user for time of delay in seconds
    int delay;
    printf("Enter delay: ");
    scanf("%d", &delay);

    // counter downtime for run a rocket while the delay with more 0
    do {
        // erase the previous line and display remain of the delay
        printf("\033[ATime left for run rocket: %d\n", delay);

        // a timeout for display

        // decrease the delay to 1

    } while (delay >= 0);

    // a string for display rocket
    char rocket[3] = "-->";

    // a string for display all trace of the rocket and the rocket itself
    char *rocket_trace = (char *) malloc(100 * sizeof(char));

    // display trace of the rocket from a start to the end
    int i;
    char passed_way[100] = "";
    for (i = 0; i <= 50; i++) {
        sprintf(rocket_trace, "%s%s", passed_way, rocket);
        passed_way[i] = ' ';
        printf("| %s\n", rocket_trace);

    // erase a line and write a new line
    puts("Good luck!");

    return 0;

Compile file, run and delete after (my preference)

$ gcc timeout.c -o timeout && ./timeout && rm timeout

Try run it for yourself to see result.


Testing environment

$ uname -a
Linux wlysenko-Aspire 3.13.0-37-generic #64-Ubuntu SMP Mon Sep 22 21:28:38 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
$ gcc --version
gcc (Ubuntu 4.8.5-2ubuntu1~14.04.1) 4.8.5
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO

How to pass variable as a parameter in Execute SQL Task SSIS?

In your Execute SQL Task, make sure SQLSourceType is set to Direct Input, then your SQL Statement is the name of the stored proc, with questionmarks for each paramter of the proc, like so:

enter image description here

Click the parameter mapping in the left column and add each paramter from your stored proc and map it to your SSIS variable:

enter image description here

Now when this task runs it will pass the SSIS variables to the stored proc.

Date ticks and rotation in matplotlib

An easy solution which avoids looping over the ticklabes is to just use


This command automatically rotates the xaxis labels and adjusts their position. The default values are a rotation angle 30° and horizontal alignment "right". But they can be changed in the function call

fig.autofmt_xdate(bottom=0.2, rotation=30, ha='right')

The additional bottom argument is equivalent to setting plt.subplots_adjust(bottom=bottom), which allows to set the bottom axes padding to a larger value to host the rotated ticklabels.

So basically here you have all the settings you need to have a nice date axis in a single command.

A good example can be found on the matplotlib page.

jQuery Data vs Attr?

You can use data-* attribute to embed custom data. The data-* attributes gives us the ability to embed custom data attributes on all HTML elements.

jQuery .data() method allows you to get/set data of any type to DOM elements in a way that is safe from circular references and therefore from memory leaks.

jQuery .attr() method get/set attribute value for only the first element in the matched set.


<span id="test" title="foo" data-kind="primary">foo</span>

$("#test").data("value", "bar");

Error:could not create the Java Virtual Machine Error:A fatal exception has occured.Program will exit

I think you have put command like java -VERSION. This is in capital letters You need to put all command in lowercase letters

javac -version
java -version

All characters must be in lowercase letter

Convert character to Date in R

You may be overcomplicating things, is there any reason you need the stringr package?

 df <- data.frame(Date = c("10/9/2009 0:00:00", "10/15/2009 0:00:00"))
 as.Date(df$Date, "%m/%d/%Y %H:%M:%S")

[1] "2009-10-09" "2009-10-15"

More generally and if you need the time component as well, use strptime:

strptime(df$Date, "%m/%d/%Y %H:%M:%S")

I'm guessing at what your actual data might look at from the partial results you give.

How to debug SSL handshake using cURL?

curl probably does have some options for showing more information but for things like this I always use openssl s_client

With the -debug option this gives lots of useful information

Maybe I should add that this also works with non HTTP connections. So if you are doing "https", try the curl commands suggested below. If you aren't or want a second option openssl s_client might be good

Apache error: _default_ virtualhost overlap on port 443

It is highly unlikely that adding NameVirtualHost *:443 is the right solution, because there are a limited number of situations in which it is possible to support name-based virtual hosts over SSL. Read this and this for some details (there may be better docs out there; these were just ones I found that discuss the issue in detail).

If you're running a relatively stock Apache configuration, you probably have this somewhere:

<VirtualHost _default_:443>

Your best bet is to either:

  • Place your additional SSL configuration into this existing VirtualHost container, or
  • Comment out this entire VirtualHost block and create a new one. Don't forget to include all the relevant SSL options.

C++ multiline string literal

In C++11 you have raw string literals. Sort of like here-text in shells and script languages like Python and Perl and Ruby.

const char * vogon_poem = R"V0G0N(
             O freddled gruntbuggly thy micturations are to me
                 As plured gabbleblochits on a lurgid bee.
              Groop, I implore thee my foonting turlingdromes.   
           And hooptiously drangle me with crinkly bindlewurdles,
Or I will rend thee in the gobberwarts with my blurlecruncheon, see if I don't.

                (by Prostetnic Vogon Jeltz; see p. 56/57)

All the spaces and indentation and the newlines in the string are preserved.

These can also be utf-8|16|32 or wchar_t (with the usual prefixes).

I should point out that the escape sequence, V0G0N, is not actually needed here. Its presence would allow putting )" inside the string. In other words, I could have put

                "(by Prostetnic Vogon Jeltz; see p. 56/57)"

(note extra quotes) and the string above would still be correct. Otherwise I could just as well have used

const char * vogon_poem = R"( ... )";

The parens just inside the quotes are still needed.

pandas unique values multiple columns

here's another way

import numpy as np

@property retain, assign, copy, nonatomic in Objective-C

Atomic property can be accessed by only one thread at a time. It is thread safe. Default is atomic .Please note that there is no keyword atomic

Nonatomic means multiple thread can access the item .It is thread unsafe

So one should be very careful while using atomic .As it affect the performance of your code

On localhost, how do I pick a free port number?

If you only need to find a free port for later use, here is a snippet similar to a previous answer, but shorter, using socketserver:

import socketserver

with socketserver.TCPServer(("localhost", 0), None) as s:
    free_port = s.server_address[1]

Note that the port is not guaranteed to remain free, so you may need to put this snippet and the code using it in a loop.

Git merge errors

as suggested in git status,

Unmerged paths:                                                                                                                                
(use "git add <file>..." to mark resolution)                                                                                                 

    both modified:   a.jl                                  
    both modified:   b.jl

I used git add to finish the merging, then git checkout works fine.

"An attempt was made to access a socket in a way forbidden by its access permissions" while using SMTP

I had a same issue. It was working fine on the local machine but it had issues on the server. I have changed the SMTP setting. It works fine for me.

If you're using GoDaddy Plesk Hosting, use the following SMTP details.

Host =
Port = 25 

Disable submit button when form invalid with AngularJS

To add to this answer. I just found out that it will also break down if you use a hyphen in your form name (Angular 1.3):

So this will not work:

<form name="my-form">
    <input name="myText" type="text" ng-model="mytext" required />
    <button ng-disabled="my-form.$invalid">Save</button>

regex.test V.S. string.match to know if a string matches a regular expression

This is my benchmark results benchmark results

test 4,267,740 ops/sec ±1.32% (60 runs sampled)

exec 3,649,719 ops/sec ±2.51% (60 runs sampled)

match 3,623,125 ops/sec ±1.85% (62 runs sampled)

indexOf 6,230,325 ops/sec ±0.95% (62 runs sampled)

test method is faster than the match method, but the fastest method is the indexOf

Get the difference between two dates both In Months and days in sql

SELECT   (MONTHS_BETWEEN(date2,date1) +  (datediff(day,date2,date1))/30) as num_months,
datediff(day,date2,date1) as diff_in_days  FROM  dual;

// You should replace date2 with TO_DATE('2012/03/25', 'YYYY/MM/DD')
// You should replace date1 with TO_DATE('2012/01/01', 'YYYY/MM/DD')
// To get you results

How to change the map center in Leaflet.js

Use map.panTo(); does not do anything if the point is in the current view. Use map.setView() instead.

I had a polyline and I had to center map to a new point in polyline at every second. Check the code : GOOD:

mymap.setView(point, 11, { animation: true });        



json Uncaught SyntaxError: Unexpected token :

That hex might need to be wrapped in quotes and made into a string. Javascript might not like the # character

Location of WSDL.exe

And on my Windows 7 machine it is here:

C:\Program Files (x86)\Microsoft SDKs\Windows\v8.1A\bin\NETFX 4.5.1 Tools

Note that the file wsdl.exe is portable, in that you can copy it to another windows machine and it works. I have not tried to see if the 4.5 exe will work on a machine that only have .NET 2.0, but this would be interesting to know.

Set bootstrap modal body height by percentage

The scss solution for Bootstrap 4.0

.modal { max-height: 100vh; .modal-dialog { .modal-content { .modal-body { max-height: calc(80vh - 140px); overflow-y: auto; } } } }

Make sure the .modal max-height is 100vh. Then for .modal-body use calc() function to calculate desired height. In above case we want to occupy 80vh of the viewport, reduced by the size of header + footer in pixels. This is around 140px together but you can measure it easily and apply your own custom values. For smaller/taller modal modify 80vh accordingly.

Drawable image on a canvas

The good way to draw a Drawable on a canvas is not decoding it yourself but leaving it to the system to do so:

Drawable d = getResources().getDrawable(R.drawable.foobar, null);
d.setBounds(left, top, right, bottom);

This will work with all kinds of drawables, not only bitmaps. And it also means that you can re-use that same drawable again if only the size changes.

How do I multiply each element in a list by a number?

You can do it in-place like so:

 l = [1, 2, 3, 4, 5]
 l[:] = [x * 5 for x in l]

This requires no additional imports and is very pythonic.

Splitting String and put it on int array

Something like this:

  public static void main(String[] args) {
   String N = "ABCD";
   char[] array = N.toCharArray();

   // and as you can see:

How can I specify system properties in Tomcat configuration on startup?

Generally you shouldn't rely on system properties to configure a webapp - they may be used to configure the container (e.g. Tomcat) but not an application running inside tomcat.

cliff.meyers has already mentioned the way you should rather use for your webapplication. That's the standard way, that also fits your question of being configurable through context.xml or server.xml means.

That said, should you really need system properties or other jvm options (like max memory settings) in tomcat, you should create a file named "bin/" or "bin/setenv.bat". These files do not exist in the standard archive that you download, but if they are present, the content is executed during startup (if you start tomcat via This is a nice way to separate your own settings from the standard tomcat settings and makes updates so much easier. No need to tweak or

(If you execute tomcat as windows servive, you usually use tomcat5w.exe, tomcat6w.exe etc. to configure the registry settings for the service.)

EDIT: Also, another possibility is to go for JNDI Resources.

TCPDF ERROR: Some data has already been output, can't send PDF file

The tcpdf file that causes the "data has already been output" is in the tcpdf folder called tcpdf.php. You can modify it:

add the line ob_end_clean(); as below (3rd last line):

public function Output($name='doc.pdf', $dest='I') {
    //LOTS OF CODE HERE....}
    switch($dest) {
        case 'I': {
        // Send PDF to the standard output
        if (ob_get_contents()) {
        $this->Error('Some data has already been output, can\'t send PDF file');}
        //some code here....}
            case 'D': {         // download PDF as file
        if (ob_get_contents()) {
    $this->Error('Some data has already been output, can\'t send PDF file');}
        case 'F':
        case 'FI':
        case 'FD': {
            // save PDF to a local file
                 //LOTS OF CODE HERE.....       break;}
        case 'E': {
            // return PDF as base64 mime email attachment)
        case 'S': {
            // returns PDF as a string
            return $this->getBuffer();
        default: {
            $this->Error('Incorrect output destination: '.$dest);
           ob_end_clean(); //add this line here 
    return '';

Now lets look at your code.
I see you have $rs and $sql mixed up. These are 2 different things working together.

if (!$conn) {
   exit("Connection Failed: " . $conn);

$sql="SELECT * FROM products"; //is products your table name?
if (!$rs) {
  exit("Error in SQL");

while (odbc_fetch_row($rs)) {
  $prodname=odbc_result($rs,"Product Name"); //but preferably never use spaces for table names.
 $prodid=odbc_result($rs,"ProdID");  //prodID is assumed attribute
  echo "$prodname";
  echo "$prodid";

now you can use the $prodname and output it to the TCPDF output.  

and I assume your are connecting to a MS access database.

Directly export a query to CSV using SQL Developer

Click in the grid so it has focus.


This will force the rest of the records back into the grid.

All credit to

Spring Data JPA find by embedded object property

The above - findByBookIdRegion() did not work for me. The following works with the latest release of String Data JPA:

Page<QueuedBook> findByBookId_Region(Region region, Pageable pageable);

How to create a link to another PHP page

Html a tag

Link in html

 <a href="index1.php">page1</a>
 <a href="page2.php">page2</a>

Html in php

echo ' <a href="index1.php">page1</a>';
echo '<a href="page2.php">page2</a>';

SQL order string as number

This will handle negative numbers, fractions, string, everything:

ORDER BY ISNUMERIC(col) DESC, Try_Parse(col AS decimal(10,2)), col;

How do you overcome the HTML form nesting limitation?

My solution is to have the buttons call JS functions which write and then submit forms outwith the main form

function removeMe(A, B){
        document.write('<form name="removeForm" method="POST" action="Delete.php">');
        document.write('<input type="hidden" name="customerID" value="' + A + '">');
        document.write('<input type="hidden" name="productID" value="' + B + '">');
function insertMe(A, B){
        document.write('<form name="insertForm" method="POST" action="Insert.php">');
        document.write('<input type="hidden" name="customerID" value="' + A + '">');
        document.write('<input type="hidden" name="productID" value="' + B + '">');

<form method="POST" action="main_form_purpose_page.php">

<input type="button" name="remove" Value="Remove" onclick="removeMe('$customerID','$productID')">
<input type="button" name="insert" Value="Insert" onclick="insertMe('$customerID','$productID')">

<input type="submit" name="submit" value="Submit">

Detect the Internet connection is offline?

request head in request error

    url: /your_url,
    type: "POST or GET",
    data: your_data,
    success: function(result){
      //do stuff
    error: function(xhr, status, error) {

      //detect if user is online and avoid the use of async
            type: "HEAD",
            url: document.location.pathname,
            error: function() { 
              //user is offline, do stuff
              console.log("you are offline"); 

Calling a Javascript Function from Console

If it's inside a closure, i'm pretty sure you can't.

Otherwise you just do functionName(); and hit return.

XmlDocument - load from string?

XmlDocument doc = new XmlDocument();

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

What's is the difference between train, validation and test set, in neural networks?

Cross-validation set is used for model selection, for example, select the polynomial model with the least amount of errors for a given parameter set. The test set is then used to report the generalization error on the selected model. From here:

Getting index value on razor foreach

I prefer to use this extension method:

public static class Extensions
    public static IEnumerable<(T item, int index)> WithIndex<T>(this IEnumerable<T> self)
        => self.Select((item, index) => (item, index));



@using Project.Shared.Helpers 

@foreach (var (item, index) in collection.WithIndex())
    Name: @item.Name Index: @index

Error inflating when extending a class

I think I figured out why this wasn't working. I was only providing a constructor for the case of one parameter 'context' when I should have provided a constructor for the two parameter 'Context, AttributeSet' case. I also needed to give the constructor(s) public access. Here's my fix:

public class GhostSurfaceCameraView extends SurfaceView implements SurfaceHolder.Callback {
        SurfaceHolder mHolder;
        Camera mCamera;

        public GhostSurfaceCameraView(Context context)
        public GhostSurfaceCameraView(Context context, AttributeSet attrs)
            super(context, attrs);
        public GhostSurfaceCameraView(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);

Virtual Memory Usage from Java under Linux, too much memory used

No, you can't configure memory amount needed by VM. However, note that this is virtual memory, not resident, so it just stays there without harm if not actually used.

Alernatively, you can try some other JVM then Sun one, with smaller memory footprint, but I can't advise here.

onchange event for html.dropdownlist

try this :

@Html.DropDownList("Sortby", new SelectListItem[] { new SelectListItem() 
{ Text = "Newest to Oldest", Value = "0" }, new SelectListItem() 
{ Text = "Oldest to Newest", Value = "1" }},
new { onchange = "document.location.href = '/ControllerName/ActionName?id=' + this.options[this.selectedIndex].value;" })

Responding with a JSON object in Node.js (converting object/array to JSON string)

in express there may be application-scoped JSON formatters.

after looking at express\lib\response.js, I'm using this routine:

function writeJsonPToRes(app, req, res, obj) {
    var replacer = app.get('json replacer');
    var spaces = app.get('json spaces');
    res.set('Content-Type', 'application/json');
    var partOfResponse = JSON.stringify(obj, replacer, spaces)
        .replace(/\u2028/g, '\\u2028')
        .replace(/\u2029/g, '\\u2029');
    var callback = req.query[app.get('jsonp callback name')];
    if (callback) {
        if (Array.isArray(callback)) callback = callback[0];
        res.set('Content-Type', 'text/javascript');
        var cb = callback.replace(/[^\[\]\w$.]/g, '');
        partOfResponse = 'typeof ' + cb + ' === \'function\' && ' + cb + '(' + partOfResponse + ');\n';

Does Python have a package/module management system?

I don't see either MacPorts or Homebrew mentioned in other answers here, but since I do see them mentioned elsewhere on Stack Overflow for related questions, I'll add my own US$0.02 that many folks seem to consider MacPorts as not only a package manager for packages in general (as of today they list 16311 packages/ports, 2931 matching "python", albeit only for Macs), but also as a decent (maybe better) package manager for Python packages/modules:


"...what is the method that Mac python developers use to manage their modules?"



"Macs (unlike Linux) don’t come with a package manager, but there are a couple of popular package managers you can install. Macports..."

I'm still debating on whether or not to use MacPorts myself, but at the moment I'm leaning in that direction.

filename.whl is not supported wheel on this platform

If you are totally new to python read step by step or go directly to 5th step directly. Follow the below method to install scipy 0.18.1 on Windows 64-bit , Python 64-bit . Be careful with the versions of 1. Python 2. Windows 3. .whl version of numpy and scipy files 4. First install numpy and then scipy.

pip install FileName.whl
  1. ForNumpy: ForScipy:

Be aware of the file name ( what I mean is check the cp no). Ex :scipy-0.18.1-cp35-cp35m-win_amd64.whl To check which cp is supported by your pip , go to point No 2 below.

If you are using .whl file . Following errors are likely to occur .

  1. You are using pip version 7.1.0, however version 8.1.2 is available.

You should consider upgrading via the 'python -m pip install --upgrade pip' command

  1. scipy-0.15.1-cp33-none-win_amd64.whl.whl is not supported wheel on this platform

For the above error : start Python(in my case 3.5), type : import pip print(pip.pep425tags.get_supported())

output :

[('cp35', 'cp35m', 'win_amd64'), ('cp35', 'none', 'win_amd64'), ('py3', 'none', 'win_amd64'), ('cp35', 'none', 'any'), ('cp3', 'none', 'any'), ('py35', 'none', 'any'), ('py3', 'none', 'any'), ('py34', 'none', 'any'), ('py33', 'none', 'any'), ('py32', 'none', 'any'), ('py31', 'none', 'any'), ('py30', 'none', 'any')]

In the output you will observe cp35 is there , so download cp35 for numpy as well as scipy. Further edits are most welcome !!!!

How to Solve Max Connection Pool Error

Check against any long running queries in your database.

Increasing your pool size will only make your webapp live a little longer (and probably get a lot slower)

You can use sql server profiler and filter on duration / reads to see which querys need optimization.

I also see you're probably keeping a global connection?


Let .net do the pooling for you and open / close your connection with a using statement.


  1. Always open and close a connection like this, so .net can manage your connections and you won't run out of connections:

        using (SqlConnection conn = new SqlConnection(connectionString))
         // do some stuff
        } //conn disposed
  2. As I mentioned, check your query with sql server profiler and see if you can optimize it. Having a slow query with many requests in a web app can give these timeouts too.

"psql: could not connect to server: Connection refused" Error when connecting to remote database

Mine was quite straightforward if you are on a Mac try:

brew install postgres

This will tell you if you have it already install and what version or install the latest version for you if not then run

brew upgrade postgresql

This will make sure you have the latest version installed then finally

brew services start postgresql

This will start the service again. I hope this helps someone.

How to remove the arrow from a select element in Firefox

I was having the same issue. It's easy to make it work on FF and Chrome, but on IE (8+ that we need to support) things get complicated. The easiest solution I could find for custom select elements that works "everywhere I tried", including IE8, is using .customSelect()

Best way to move files between S3 buckets?


As pointed out by alberge (+1), nowadays the excellent AWS Command Line Interface provides the most versatile approach for interacting with (almost) all things AWS - it meanwhile covers most services' APIs and also features higher level S3 commands for dealing with your use case specifically, see the AWS CLI reference for S3:

  • sync - Syncs directories and S3 prefixes. Your use case is covered by Example 2 (more fine grained usage with --exclude, --include and prefix handling etc. is also available):

    The following sync command syncs objects under a specified prefix and bucket to objects under another specified prefix and bucket by copying s3 objects. [...]

    aws s3 sync s3://from_my_bucket s3://to_my_other_bucket

For completeness, I'll mention that the lower level S3 commands are also still available via the s3api sub command, which would allow to directly translate any SDK based solution to the AWS CLI before adopting its higher level functionality eventually.

Initial Answer

Moving files between S3 buckets can be achieved by means of the PUT Object - Copy API (followed by DELETE Object):

This implementation of the PUT operation creates a copy of an object that is already stored in Amazon S3. A PUT copy operation is the same as performing a GET and then a PUT. Adding the request header, x-amz-copy-source, makes the PUT operation copy the source object into the destination bucket. Source

There are respective samples for all existing AWS SDKs available, see Copying Objects in a Single Operation. Naturally, a scripting based solution would be the obvious first choice here, so Copy an Object Using the AWS SDK for Ruby might be a good starting point; if you prefer Python instead, the same can be achieved via boto as well of course, see method copy_key() within boto's S3 API documentation.

PUT Object only copies files, so you'll need to explicitly delete a file via DELETE Object still after a successful copy operation, but that will be just another few lines once the overall script handling the bucket and file names is in place (there are respective examples as well, see e.g. Deleting One Object Per Request).

Remove quotes from a character vector in R

I think I was trying something very similar to the original poster. the get() worked for me, although the name inside the chart was not inherited. Here is the code that worked for me.

#install it if you dont have it

# a list of stock tickers
myStocks <- c("INTC", "AAPL", "GOOG", "LTD")

# get some stock prices from default service

# to pause in between plots

# plot all symbols
for (i in 1:length(myStocks)) {
    chartSeries(get(myStocks[i]), subset="last 26 weeks")

Android Studio: Where is the Compiler Error Output Window?

This answer is outdated. For Android 3.1 Studio go to this answer

One thing you can do is deactivate the external build. To do so click on "compiler settings icon" in the "Messages Make" panel that appears when you have an error. You can also open the compiler settings by going to File -> Settings -> Compiler. (Thanx to @maxgalbu for this tip).

enter image description here

Uncheck "Use External build"

enter image description here

And you will see the errors in the console

EDIT: After returning to "internal build" again you may get some errors, you can solve them this way: Android Studio: disabling "External build" to display error output create duplicate class errors

Regular Expression to reformat a US phone number in Javascript

Assuming you want the format "(123) 456-7890":

function formatPhoneNumber(phoneNumberString) {
  var cleaned = ('' + phoneNumberString).replace(/\D/g, '')
  var match = cleaned.match(/^(\d{3})(\d{3})(\d{4})$/)
  if (match) {
    return '(' + match[1] + ') ' + match[2] + '-' + match[3]
  return null

Here's a version that allows the optional +1 international code:

function formatPhoneNumber(phoneNumberString) {
  var cleaned = ('' + phoneNumberString).replace(/\D/g, '')
  var match = cleaned.match(/^(1|)?(\d{3})(\d{3})(\d{4})$/)
  if (match) {
    var intlCode = (match[1] ? '+1 ' : '')
    return [intlCode, '(', match[2], ') ', match[3], '-', match[4]].join('')
  return null
formatPhoneNumber('+12345678900') // => "+1 (234) 567-8900"
formatPhoneNumber('2345678900')   // => "(234) 567-8900"

Bulk load data conversion error (type mismatch or invalid character for the specified codepage) for row 1, column 4 (Year)

Try using a format file since your data file only has 4 columns. Otherwise, try OPENROWSET or use a staging table.

myTestFormatFiles.Fmt may look like:

1       SQLINT        0       3       ","      1     StudentNo      ""
2       SQLCHAR       0       100     ","      2     FirstName      SQL_Latin1_General_CP1_CI_AS
3       SQLCHAR       0       100     ","      3     LastName       SQL_Latin1_General_CP1_CI_AS
4       SQLINT        0       4       "\r\n"   4     Year           "


This tutorial on skipping a column with BULK INSERT may also help.

Your statement then would look like:

USE xta9354
BULK INSERT xta9354.dbo.Students
    FROM 'd:\userdata\xta9_Students.txt' 
    WITH (FORMATFILE = 'C:\myTestFormatFiles.Fmt')

Homebrew refusing to link OpenSSL

After trying everything I could find and nothing worked, I just tried this:

touch ~/.bash_profile; open ~/.bash_profile

Inside the file added this line.

export PATH="$PATH:/usr/local/Cellar/openssl/1.0.2j/bin/openssl"

now it works :)

Jorns-iMac:~ jorn$ openssl version -a
OpenSSL 1.0.2j  26 Sep 2016
built on: reproducible build, date unspecified
//blah blah
OPENSSLDIR: "/usr/local/etc/openssl"

Jorns-iMac:~ jorn$ which openssl

How can I get a random number in Kotlin?

Whenever there is a situation where you want to generate key or mac address which is hexadecimal number having digits based on user demand, and that too using android and kotlin, then you my below code helps you:

private fun getRandomHexString(random: SecureRandom, numOfCharsToBePresentInTheHexString: Int): String {
    val sb = StringBuilder()
    while (sb.length < numOfCharsToBePresentInTheHexString) {
        val randomNumber = random.nextInt()
        val number = String.format("%08X", randomNumber)
    return sb.toString()

Filtering by Multiple Specific Model Properties in AngularJS (in OR relationship)

I solved this simply:

<div ng-repeat="Object in List | filter: (FilterObj.FilterProperty1 ? {'ObjectProperty1': FilterObj.FilterProperty1} : '') | filter:(FilterObj.FilterProperty2 ? {'ObjectProperty2': FilterObj.FilterProperty2} : '')">

ImportError: No module named sklearn.cross_validation

train_test_split is part of the module sklearn.model_selection, hence, you may need to import the module from model_selection


from sklearn.model_selection import train_test_split

How do I view Android application specific cache?

Cached files are indeed stored in /data/data/my_app_package/cache

Make sure to store the files using the following method:

String cacheDir = context.getCacheDir();
File imageFile = new File(cacheDir, "image1.jpg");
FileOutputStream out = new FileOutputStream(imageFile);
out.write(imagebuffer, 0, imagebufferlength);

where imagebuffer[] contains image data in byte format and imagebufferlength is the length of the content to be written to the FileOutputStream.

Now, you may look at DDMS File Explorer or do an "adb shell" and cd to /data/data/my_app_package/cache and do an "ls". You will find the image files you have stored through code in this directory.

Moreover, from Android documentation:

If you'd like to cache some data, rather than store it persistently, you should use getCacheDir() to open a File that represents the internal directory where your application should save temporary cache files.

When the device is low on internal storage space, Android may delete these cache files to recover space. However, you should not rely on the system to clean up these files for you. You should always maintain the cache files yourself and stay within a reasonable limit of space consumed, such as 1MB. When the user uninstalls your application, these files are removed.

Start and stop a timer PHP

As alternative, php has a built-in timer controller: new EvTimer().

It can be used to make a task scheduler, with proper handling of special cases.

This is not only the Time, but a time transport layer, a chronometer, a lap counter, just as a stopwatch but with php callbacks ;)

EvTimer watchers are simple relative timers that generate an event after a given time, and optionally repeating in regular intervals after that.

The timers are based on real time, that is, if one registers an event that times out after an hour and resets the system clock to January last year, it will still time out after(roughly) one hour.

The callback is guaranteed to be invoked only after its timeout has passed (...). If multiple timers become ready during the same loop iteration then the ones with earlier time-out values are invoked before ones of the same priority with later time-out values.

The timer itself will do a best-effort at avoiding drift, that is, if a timer is configured to trigger every 10 seconds, then it will normally trigger at exactly 10 second intervals. If, however, the script cannot keep up with the timer because it takes longer than those 10 seconds to do) the timer will not fire more than once per event loop iteration.

The first two parameters allows to controls the time delay before execution, and the number of iterations.

The third parameter is a callback function, called at each iteration.


    Configures the timer to trigger after after seconds.


    If repeat is 0.0 , then it will automatically be stopped once the timeout is reached.
    If it is positive, then the timer will automatically be configured to trigger again every repeat seconds later, until stopped manually.

$w2 = new EvTimer(2, 1, function ($w) {
    echo "is called every second, is launched after 2 seconds\n";
    echo "iteration = ", Ev::iteration(), PHP_EOL;

    // Stop the watcher after 5 iterations
    Ev::iteration() == 5 and $w->stop();
    // Stop the watcher if further calls cause more than 10 iterations
    Ev::iteration() >= 10 and $w->stop();

We can of course easily create this with basic looping and some tempo with sleep(), usleep(), or hrtime(), but new EvTimer() allows cleans and organized multiples calls, while handling special cases like overlapping.

What is the difference between Task.Run() and Task.Factory.StartNew()

Apart from the similarities i.e. Task.Run() being a shorthand for Task.Factory.StartNew(), there is a minute difference between their behaviour in case of sync and async delegates.

Suppose there are following two methods:

public async Task<int> GetIntAsync()
    return Task.FromResult(1);

public int GetInt()
    return 1;

Now consider the following code.

var sync1 = Task.Run(() => GetInt());
var sync2 = Task.Factory.StartNew(() => GetInt());

Here both sync1 and sync2 are of type Task<int>

However, difference comes in case of async methods.

var async1 = Task.Run(() => GetIntAsync());
var async2 = Task.Factory.StartNew(() => GetIntAsync());

In this scenario, async1 is of type Task<int>, however async2 is of type Task<Task<int>>

Remove characters after specific character in string, then remove substring?

you can use .NET's built in method to remove the QueryString. i.e., Request.QueryString.Remove["whatever"];

here whatever in the [ ] is name of the querystring which you want to remove.

Try this... I hope this will help.

How to check if JSON return is empty with jquery

Just test if the array is empty.

    if ( json.length == 0 ) {
        console.log("NO DATA!")

How to set fake GPS location on IOS real device

Create a .GPX file with xcode, then specify your coordinates and when your device connected, hit the little arrow button and select your .GPX file. You can create multiple files and add lots of coordinates to single .GPX file in order to make some kind of route.

global variable for all controller and views

In Laravel, 5+ you can create a file in the config folder and create variables in that and use that across the app. For instance, I want to store some information based on the site. I create a file called site_vars.php, which looks like this

return [
    'supportEmail' => '[email protected]',
    'adminEmail' => '[email protected]'

Now in the routes, controller, views you can access it using


In the views if I this

{{ Config::get('site_vars.supportEmail') }}

It will give [email protected]

Hope this helps.

EDiT- You can also define vars in .env file and use them here. That is the best way in my opinion as it gives you the flexibility to use values that you want on your local machine.

So, you can do something this in the array

'supportEmail' => env('SUPPORT_EMAIL', '[email protected]')

Important - After you do this, don't forget to do

php artisan config:cache

In case, there's still some problem, then you can do this (usually it would never happen but still if it ever happens)

php artisan cache:clear
php artisan config:cache

Android textview usage as label and value

You can use <LinearLayout> to group elements horizontaly. Also you should use style to set margins, background and other properties. This will allow you not to repeat code for every label you use. Here is an example:



Also you can create a custom view base on the layout above. Have you looked at Creating custom view ?

How to find children of nodes using BeautifulSoup

There's a super small section in the DOCs that shows how to find/find_all direct children.

In your case as you want link1 which is first direct child:

# for only first direct child
soup.find("li", { "class" : "test" }).find("a", recursive=False)

If you want all direct children:

# for all direct children
soup.find("li", { "class" : "test" }).findAll("a", recursive=False)

RuntimeError: module compiled against API version a but this version of numpy is 9

upgrade numpy to the latest version

pip install numpy --upgrade

How can I convert tabs to spaces in every file of a directory?

Warning: This will break your repo.

This will corrupt binary files, including those under svn, .git! Read the comments before using!

find . -iname '*.java' -type f -exec sed -i.orig 's/\t/ /g' {} +

The original file is saved as [filename].orig.

Replace '*.java' with the file ending of the file type you are looking for. This way you can prevent accidental corruption of binary files.


  • Will replace tabs everywhere in a file.
  • Will take a long time if you happen to have a 5GB SQL dump in this directory.

How to run a cron job on every Monday, Wednesday and Friday?

Use crontab to add job

0 0 9 ? * MON,WED,FRI *

The above expression will run the job at 9 am on every mon, wed and friday. You can validate this in :

How to sort by Date with DataTables jquery plugin?

As of 2015, the most convenient way according to me to sort Date column in a DataTable, is using the required sort plugin. Since the date format in my case was dd/mm/yyyy hh:mm:ss, I ended up using the date-euro plugin. All one needs to do is:

Step 1: Include the sorting plugin JavaScript file or code and;

Step 2: Add columnDefs as shown below to target appropriate column(s).

$('#example').dataTable( {
    columnDefs: [
       { type: 'date-euro', targets: 0 }

How to store Emoji Character in MySQL Database

Both the databases and tables should have character set utf8mb4 and collation utf8mb4_unicode_ci.

When creating a new database you should use:

CREATE DATABASE mydb CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

If you have an existing database and you want to add support:

ALTER DATABASE database_name CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;

You also need to set the correct character set and collation for your tables:

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE utf8mb4_unicode_ci;

or change it if you've got existing tables with a lot of data:

ALTER TABLE table_name CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Note that utf8_general_ci is no longer recommended best practice. See the related Q & A:

What's the difference between utf8_general_ci and utf8_unicode_ci on Stack Overflow.

What's a good hex editor/viewer for the Mac?

One recommendation I've gotten is Hex Fiend.

Checking host availability by using ping in bash scripts

You don't need the backticks in the if statement. You can use this check

if ping -c 1 some_ip_here &> /dev/null
  echo 1
  echo 0

The if command checks the exit code of the following command (the ping). If the exit code is zero (which means that the command exited successfully) the then block will be executed. If it return a non-zero exit code, then the else block will be executed.

Setting Spring Profile variable

For Tomcat 8:

Linux :

Create and update it with following:



Create setenv.bat and update it with following:


Bootstrap: How do I identify the Bootstrap version?

The easiest would be to locate the bootstrap file (bootstrap.css OR bootstrap.min.css) and read through the docblock, you'll see something like this

Bootstrap v3.3.6 (

SQL Server: Filter output of sp_who2

One way is to create a temp table:

CREATE TABLE #sp_who2 
   SPID INT,  
   Status VARCHAR(1000) NULL,  
   Login SYSNAME NULL,  
   HostName SYSNAME NULL,  
   Command VARCHAR(1000) NULL,  
   CPUTime INT NULL,  
   DiskIO INT NULL,  
   LastBatch VARCHAR(1000) NULL,  
   ProgramName VARCHAR(1000) NULL,  

INSERT INTO #sp_who2
EXEC sp_who2

FROM #sp_who2
WHERE Login = 'bla'

DROP TABLE #sp_who2

Only using @JsonIgnore during serialization, but not deserialization

In my case, I have Jackson automatically (de)serializing objects that I return from a Spring MVC controller (I am using @RestController with Spring 4.1.6). I had to use com.fasterxml.jackson.annotation.JsonIgnore instead of org.codehaus.jackson.annotate.JsonIgnore, as otherwise, it simply did nothing.

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

They are equivalent in effect, pointing to different shortcuts:

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

And the other..

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

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

How to list all the roles existing in Oracle database?


SELECT SUBSTR(TRIM(rtp.role),1,12)          AS ROLE
     , SUBSTR(rp.grantee,1,16)              AS GRANTEE
     , SUBSTR(TRIM(rtp.privilege),1,12)     AS PRIVILEGE
     , SUBSTR(TRIM(rtp.owner),1,12)         AS OWNER
     , SUBSTR(TRIM(rtp.table_name),1,28)    AS TABLE_NAME
     , SUBSTR(TRIM(rtp.column_name),1,20)   AS COLUMN_NAME
     , SUBSTR(rtp.common,1,4)               AS COMMON
     , SUBSTR(rtp.grantable,1,4)            AS GRANTABLE
     , SUBSTR(rp.default_role,1,16)         AS DEFAULT_ROLE
     , SUBSTR(rp.admin_option,1,4)          AS ADMIN_OPTION
  FROM role_tab_privs rtp
  LEFT JOIN dba_role_privs rp
    ON (rtp.role = rp.granted_role)
 WHERE ('&1' IS NULL OR UPPER(rtp.role) LIKE UPPER('%&1%'))
   AND ('&2' IS NULL OR UPPER(rp.grantee) LIKE UPPER('%&2%'))
   AND ('&3' IS NULL OR UPPER(rtp.table_name) LIKE UPPER('%&3%'))
   AND ('&4' IS NULL OR UPPER(rtp.owner) LIKE UPPER('%&4%'))
        , 2
        , 3
        , 4


SQLPLUS> @all_roles '' '' '' '' '' ''
SQLPLUS> @all_roles 'somerol' '' '' '' '' ''
SQLPLUS> @all_roles 'roler' 'username' '' '' '' ''
SQLPLUS> @all_roles '' '' 'part-of-database-package-name' '' '' ''

New to MongoDB Can not run command mongo

mongod --dbpath "c://data/db"

run the above code, this will start the server.

What is the "Illegal Instruction: 4" error and why does "-mmacosx-version-min=10.x" fix it?

The "illegal instruction" message is simply telling you that your binaries contain instructions the version of the OS that you are attempting to run them under does not understand. I can't give you the precise meaning of 4 but I expect that is internal to Apple.

Otherwise take a look at these... they are a little old, but probably tell you what you need to know

How does 64 bit code work on OS-X 10.5?
what does macosx-version-min imply?

Remove Primary Key in MySQL

In case you have composite primary key, do like this- ALTER TABLE table_name DROP PRIMARY KEY,ADD PRIMARY KEY (col_name1, col_name2);

How can I get an HTTP response body as a string?

Here's an example from another simple project I was working on using the httpclient library from Apache:

String response = new String();
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
nameValuePairs.add(new BasicNameValuePair("j", request));
HttpEntity requestEntity = new UrlEncodedFormEntity(nameValuePairs);

HttpPost httpPost = new HttpPost(mURI);
HttpResponse httpResponse = mHttpClient.execute(httpPost);
HttpEntity responseEntity = httpResponse.getEntity();
if(responseEntity!=null) {
    response = EntityUtils.toString(responseEntity);

just use EntityUtils to grab the response body as a String. very simple.

Get class name using jQuery

Be Careful , Perhaps , you have a class and a subclass .

  <div id='id' class='myclass mysubclass' >dfdfdfsdfds</div>

If you use previous solutions , you will have :

myclass mysubclass

So if you want to have the class selector, do the following :

var className = '.'+$('#id').attr('class').split(' ').join('.')

and you will have


Now if you want to select all elements that have the same class such as div above :

   var brothers=$('.'+$('#id').attr('class').split(' ').join('.'))

that means

var brothers=$('.myclass.mysubclass')

Update 2018

OR can be implemented with vanilla javascript in 2 lines:

  const { classList } = document.querySelector('#id');

Disabling vertical scrolling in UIScrollView

- (void)scrollViewDidScroll:(UIScrollView *)aScrollView
    [aScrollView setContentOffset: CGPointMake(aScrollView.contentOffset.x,0)];


you must have confirmed to UIScrollViewDelegate

aScrollView.delegate = self;

In .NET, which loop runs faster, 'for' or 'foreach'?

Unless you're in a specific speed optimization process, I would say use whichever method produces the easiest to read and maintain code.

If an iterator is already setup, like with one of the collection classes, then the foreach is a good easy option. And if it's an integer range you're iterating, then for is probably cleaner.

Disable Rails SQL logging in console

Here's a variation I consider somewhat cleaner, that still allows potential other logging from AR. In config/environments/development.rb :

config.after_initialize do
  ActiveRecord::Base.logger = Rails.logger.clone
  ActiveRecord::Base.logger.level = Logger::INFO

Create a .txt file if doesn't exist, and if it does append a new line

string path=@"E:\AppServ\Example.txt";


   using( TextWriter tw = new StreamWriter(path))
      tw.WriteLine("The very first line!");

else if (File.Exists(path))
   using(TextWriter tw = new StreamWriter(path))
      tw.WriteLine("The next line!");

Pandas: sum DataFrame rows for given columns

Following syntax helped me when I have columns in sequence

awards_frame.values[:,1:4].sum(axis =1)

Problem with SMTP authentication in PHP using PHPMailer, with Pear Mail works

Try adding this:

$mail->SMTPAuth   = true;
$mail->SMTPSecure = "tls";

By looking at your debug logs, you can notice that the failing PhpMailer log shows this:

SMTP -> ERROR: AUTH not accepted from server: 250 Hello []
503 AUTH command used when not advertised

While your successful PEAR log shows this:

DEBUG: Recv: 220 TLS go ahead

My guess is that explicitly asking PHPMailer to use TLS will put it on the right track.
Also, make sure you're using the latest versin of PHPMailer.

A cycle was detected in the build path of project xxx - Build Path Problem

When I've had these problems it always has been a true cycle in the dependencies expressed in

So open the manifest of the project in question, on the Dependencies Tab, look at the "Required Plugins" entry. Then follow from there to the next project(s), and repeat eventually the cycle will become clear.

You can simpify this task somewhat by using the Dependency Analysis links in the bottom right corner of the Dependencies Tab, this has cycle detection and easier navigation depdendencies.

I also don't know why Maven is more tolerant,

When do I have to use interfaces instead of abstract classes?

Abstract classes can contain methods that are not abstract, whereas in interfaces all your methods are abstract and have to be implemented.

You should use interfaces instead when you know you will always implement those certain methods. Also you can inherit from multiple interfaces, it is java's way of dealing with multiple inheritance

Change "on" color of a Switch

Try to find out right answer here: Selector on background color of TextView. In two words you should create Shape in XML with color and then assign it to state "checked" in your selector.

Send response to all clients except sender

Here is a more complete answer about what has changed from 0.9.x to 1.x.

 // send to current request socket client
 socket.emit('message', "this is a test");// Hasn't changed

 // sending to all clients, include sender
 io.sockets.emit('message', "this is a test"); // Old way, still compatible
 io.emit('message', 'this is a test');// New way, works only in 1.x

 // sending to all clients except sender
 socket.broadcast.emit('message', "this is a test");// Hasn't changed

 // sending to all clients in 'game' room(channel) except sender'game').emit('message', 'nice game');// Hasn't changed

 // sending to all clients in 'game' room(channel), include sender'game').emit('message', 'cool game');// Old way, DOES NOT WORK ANYMORE'game').emit('message', 'cool game');// New way'game').emit('message', 'cool game');// New way, "in" or "to" are the exact same: "And then simply use to or in (they are the same) when broadcasting or emitting:" from

 // sending to individual socketid, socketid is like a room
 io.sockets.socket(socketid).emit('message', 'for your eyes only');// Old way, DOES NOT WORK ANYMORE'message', 'for your eyes only');// New way

I wanted to edit the post of @soyuka but my edit was rejected by peer-review.

Excel 2007 - Compare 2 columns, find matching values

=VLOOKUP(lookup_value,table_array,col_index_num,range_lookup) will solve this issue.

This will search for a value in the first column to the left and return the value in the same row from a specific column.

How to Convert Boolean to String

The other solutions here all have caveats (though they address the question at hand). If you are (1) looping over mixed-types or (2) want a generic solution that you can export as a function or include in your utilities, none of the other solutions here will work.

The simplest and most self-explanatory solution is:

// simplest, most-readable
if (is_bool($res) {
    $res = $res ? 'true' : 'false';

// same as above but written more tersely
$res = is_bool($res) ? ($res ? 'true' : 'false') : $res;

// Terser still, but completely unnecessary  function call and must be
// commented due to poor readability. What is var_export? What is its
// second arg? Why are we exporting stuff?
$res = is_bool($res) ? var_export($res, 1) : $res;

But most developers reading your code will require a trip to to understand what the var_export does and what the second param is.

1. var_export

Works for boolean input but converts everything else to a string as well.

// OK
var_export(false, 1); // 'false'
// OK
var_export(true, 1);  // 'true'
var_export('', 1);  // '\'\''
var_export(1, 1);  // '1'

2. ($res) ? 'true' : 'false';

Works for boolean input but converts everything else (ints, strings) to true/false.

// OK
true ? 'true' : 'false' // 'true'
// OK
false ? 'true' : 'false' // 'false'
'' ? 'true' : 'false' // 'false'
0 ? 'true' : 'false' // 'false'

3. json_encode()

Same issues as var_export and probably worse since json_encode cannot know if the string true was intended a string or a boolean.

VBA Excel sort range by specific column

Try this code:

Dim lastrow As Long
lastrow = Cells(Rows.Count, 2).End(xlUp).Row
Range("A3:D" & lastrow).Sort key1:=Range("B3:B" & lastrow), _
   order1:=xlAscending, Header:=xlNo

How can I find all *.js file in directory recursively in Linux?

If you just want the list, then you should ask here:

The answer is: cd / && find -name *.js

If you want to implement this, you have to specify the language.

How to get rid of "Unnamed: 0" column in a pandas DataFrame?

Simple do this:

df = df.loc[:, ~df.columns.str.contains('^Unnamed')]

Merge two objects with ES6

You can use Object.assign() to merge them into a new object:

const response = {_x000D_
  lat: -51.3303,_x000D_
  lng: 0.39440_x000D_
const item = {_x000D_
  id: 'qwenhee-9763ae-lenfya',_x000D_
  address: '14-22 Elder St, London, E1 6BT, UK'_x000D_
const newItem = Object.assign({}, item, { location: response });_x000D_
console.log(newItem );

You can also use object spread, which is a Stage 4 proposal for ECMAScript:

const response = {_x000D_
  lat: -51.3303,_x000D_
  lng: 0.39440_x000D_
const item = {_x000D_
  id: 'qwenhee-9763ae-lenfya',_x000D_
  address: '14-22 Elder St, London, E1 6BT, UK'_x000D_
const newItem = { ...item, location: response }; // or { ...response } if you want to clone response as well_x000D_
console.log(newItem );

From an array of objects, extract value of a property as array

In general, if you want to extrapolate object values which are inside an array (like described in the question) then you could use reduce, map and array destructuring.


let a = [{ z: 'word', c: 'again', d: 'some' }, { u: '1', r: '2', i: '3' }];
let b = a.reduce((acc, obj) => [...acc, Object.values(obj).map(y => y)], []);


The equivalent using for in loop would be:

for (let i in a) {
  let temp = [];
  for (let j in a[i]) {

Produced output: ["word", "again", "some", "1", "2", "3"]

How to add parameters to a HTTP GET request in Android?

The method



httpget.getParams().setParameter("http.socket.timeout", new Integer(5000));

only adds HttpProtocol parameters.

To execute the httpGet you should append your parameters to the url manually

HttpGet myGet = new HttpGet("");

or use the post request the difference between get and post requests are explained here, if you are interested

How to determine whether an object has a given property in JavaScript

One feature of my original code

if ( typeof(x.y) != 'undefined' ) ...

that might be useful in some situations is that it is safe to use whether x exists or not. With either of the methods in gnarf's answer, one should first test for x if there is any doubt if it exists.

So perhaps all three methods have a place in one's bag of tricks.

JSTL if tag for equal strings

I think the other answers miss one important detail regarding the property name to use in the EL expression. The rules for converting from the method names to property names are specified in 'Introspector.decpitalize` which is part of the java bean standard:

This normally means converting the first character from upper case to lower case, but in the (unusual) special case when there is more than one character and both the first and second characters are upper case, we leave it alone.

Thus "FooBah" becomes "fooBah" and "X" becomes "x", but "URL" stays as "URL".

So in your case the JSTL code should look like the following, note the capital 'P':

<c:if test = "${ansokanInfo.PSystem == 'NAT'}">

How to scanf only integer and repeat reading if the user enters non-numeric characters?

char check1[10], check2[10];
int foo;

  printf(">> ");
  scanf(" %s", check1);
  foo = strtol(check1, NULL, 10); // convert the string to decimal number
  sprintf(check2, "%d", foo); // re-convert "foo" to string for comparison
} while (!(strcmp(check1, check2) == 0 && 0 < foo && foo < 24)); // repeat if the input is not number

If the input is number, you can use foo as your input.

Setting environment variables via launchd.conf no longer works in OS X Yosemite/El Capitan/macOS Sierra/Mojave?

I added the variables in the ~/.bash_profile in the following way. After you are done restart/log out and log in

export M2_HOME=/Users/robin/softwares/apache-maven-3.2.3
export ANT_HOME=/Users/robin/softwares/apache-ant-1.9.4
launchctl setenv M2_HOME $M2_HOME
launchctl setenv ANT_HOME $ANT_HOME
export PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/Users/robin/softwares/apache-maven-3.2.3/bin:/Users/robin/softwares/apache-ant-1.9.4/bin
launchctl setenv PATH $PATH

NOTE: without restart/log out and log in you can apply these changes using;

source ~/.bash_profile

jquery loop on Json data using $.each

getJSON will evaluate the data to JSON for you, as long as the correct content-type is used. Make sure that the server is returning the data as application/json.

What is the simplest method of inter-process communication between 2 C# processes?

The easiest solution in C# for inter-process communication when security is not a concern and given your constraints (two C# processes on the same machine) is the Remoting API. Now Remoting is a legacy technology (not the same as deprecated) and not encouraged for use in new projects, but it does work well and does not require a lot of pomp and circumstance to get working.

There is an excellent article on MSDN for using the class IpcChannel from the Remoting framework (credit to Greg Beech for the find here) for setting up a simple remoting server and client.

I Would suggest trying this approach first, and then try to port your code to WCF (Windows Communication Framework). Which has several advantages (better security, cross-platform), but is necessarily more complex. Luckily MSDN has a very good article for porting code from Remoting to WCF.

If you want to dive in right away with WCF there is a great tutorial here.


You can also use this stored procedure if you only want to truncate all tables in a specific schema:

-- =============================================
-- Author:      Ben de Ridder
-- Create date: 20160513
-- Description: Truncate all tables in schema
-- =============================================
CREATE PROCEDURE TruncateAllTablesInSchema
    @schema nvarchar(50)
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.

    DECLARE @table nVARCHAR(255)

    DECLARE db_cursor CURSOR FOR 
          from sys.tables t inner join
               sys.schemas s on 
         order by 1

    OPEN db_cursor   

    FETCH NEXT FROM db_cursor INTO @table   

           declare @sql nvarchar(1000)

           set @sql = 'truncate table [' + @schema + '].[' + @table + ']'

           exec sp_sqlexec @sql

           FETCH NEXT FROM db_cursor INTO @table   

    CLOSE db_cursor   
    DEALLOCATE db_cursor 


Html.Partial vs Html.RenderPartial & Html.Action vs Html.RenderAction

@Html.Partial and @Html.RenderPartial are used when your Partial view model is correspondence of parent model, we don't need to create any action method to call this.

@Html.Action and @Html.RenderAction are used when your partial view model are independent from parent model, basically it is used when you want to display any widget type content on page. You must create an action method which returns a partial view result while calling the method from view.

Use dynamic variable names in JavaScript

This is an alternative for those who need to export a dynamically named variable

export {
  [someVariable]: 'some value',
  [anotherVariable]: 'another value',

// then.... import from another file like this:
import * as vars from './some-file'

Another alternative is to simply create an object whose keys are named dynamically

const vars = { [someVariable]: 1, [otherVariable]: 2 };

// consume it like this

"Retrieving the COM class factory for component.... error: 80070005 Access is denied." (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))

  1. give the read / write permission to the IIS user or group users

  2. Start -> run -> inetmgr

    enable the ASP.NET authentication for your default website

3. For 64-bit (x64), create this folder: C:\Windows\SysWOW64\config\systemprofile\Desktop

For 32-bit (x86), create this folder: C:\Windows\System32\config\systemprofile\Desktop

The windows service, if running under the systemprofile, needs the Desktop folder. This folder was automatically created on XP and older Windows Server versions, but not for Vista and Windows 2008 Server.

How can I convert string to double in C++?

I think atof is exactly what you want. This function parses a string and converts it into a double. If the string does not start with a number (non-numerical) a 0.0 is returned.

However, it does try to parse as much of the string as it can. In other words, the string "3abc" would be interpreted as 3.0. If you want a function that will return 0.0 in these cases, you will need to write a small wrapper yourself.

Also, this function works with the C-style string of a null terminated array of characters. If you're using a string object, it will need to be converted to a char* before you use this function.

Google Chrome display JSON AJAX response as tree and not as a plain text

I've found the answer:

You MUST encode your json like this: {"c":21001,"m":"p"} but not {c:21001,m:"p"} or {'c':21001,'m':'p'}

Thus, the key of a dict must be wrapped in double quotes:", then chrome will preview it as json rather than plain text.

How to use multiple conditions (With AND) in IIF expressions in ssrs

Here is an example that should give you some idea..

=IIF(First(Fields!Gender.Value,"vw_BrgyClearanceNew")="Female" and 

I think you have to identify the datasource name or the table name where your data is coming from.

C# Sort and OrderBy comparison

Darin Dimitrov's answer shows that OrderBy is slightly faster than List.Sort when faced with already-sorted input. I modified his code so it repeatedly sorts the unsorted data, and OrderBy is in most cases slightly slower.

Furthermore, the OrderBy test uses ToArray to force enumeration of the Linq enumerator, but that obviously returns a type (Person[]) which is different from the input type (List<Person>). I therefore re-ran the test using ToList rather than ToArray and got an even bigger difference:

Sort: 25175ms
OrderBy: 30259ms
OrderByWithToList: 31458ms

The code:

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;

class Program
    class NameComparer : IComparer<string>
        public int Compare(string x, string y)
            return string.Compare(x, y, true);

    class Person
        public Person(string id, string name)
            Id = id;
            Name = name;
        public string Id { get; set; }
        public string Name { get; set; }
        public override string ToString()
            return Id + ": " + Name;

    private static Random randomSeed = new Random();
    public static string RandomString(int size, bool lowerCase)
        var sb = new StringBuilder(size);
        int start = (lowerCase) ? 97 : 65;
        for (int i = 0; i < size; i++)
            sb.Append((char)(26 * randomSeed.NextDouble() + start));
        return sb.ToString();

    private class PersonList : List<Person>
        public PersonList(IEnumerable<Person> persons)
           : base(persons)

        public PersonList()

        public override string ToString()
            var names = Math.Min(Count, 5);
            var builder = new StringBuilder();
            for (var i = 0; i < names; i++)
                builder.Append(this[i]).Append(", ");
            return builder.ToString();

    static void Main()
        var persons = new PersonList();
        for (int i = 0; i < 100000; i++)
            persons.Add(new Person("P" + i.ToString(), RandomString(5, true)));

        var unsortedPersons = new PersonList(persons);

        const int COUNT = 30;
        Stopwatch watch = new Stopwatch();
        for (int i = 0; i < COUNT; i++)
        Console.WriteLine("Sort: {0}ms", watch.ElapsedMilliseconds);

        watch = new Stopwatch();
        for (int i = 0; i < COUNT; i++)
        Console.WriteLine("OrderBy: {0}ms", watch.ElapsedMilliseconds);

        watch = new Stopwatch();
        for (int i = 0; i < COUNT; i++)
        Console.WriteLine("OrderByWithToList: {0}ms", watch.ElapsedMilliseconds);

    static void Sort(List<Person> list)
        list.Sort((p1, p2) => string.Compare(p1.Name, p2.Name, true));

    static void OrderBy(List<Person> list)
        var result = list.OrderBy(n => n.Name, new NameComparer()).ToArray();

    static void OrderByWithToList(List<Person> list)
        var result = list.OrderBy(n => n.Name, new NameComparer()).ToList();

Difference between & and && in Java?

&& == logical AND

& = bitwise AND

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

well I think the problem solved this below code works:

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

How to concatenate strings of a string field in a PostgreSQL 'group by' query?

I claim no credit for the answer because I found it after some searching:

What I didn't know is that PostgreSQL allows you to define your own aggregate functions with CREATE AGGREGATE

This post on the PostgreSQL list shows how trivial it is to create a function to do what's required:

  basetype    = text,
  sfunc       = textcat,
  stype       = text,
  initcond    = ''

SELECT company_id, textcat_all(employee || ', ')
FROM mytable
GROUP BY company_id;

How to create circular ProgressBar in android?

You can try this Circle Progress library

enter image description here

enter image description here

NB: please always use same width and height for progress views







How to remove "onclick" with JQuery?

After trying so hard with bind, unbind, on, off, click, attr, removeAttr, prop I made it work. So, I have the following scenario: In my html i have NOT attached any inline onclick handlers.

Then in my Javascript i used the following to add an inline onclick handler:


To remove this at a later point from Javascript I used the following:


This is the way it worked for me to bind and unbind click events dinamically in Javascript. Remember NOT to insert any inline onclick handler in your elements.

How do Python functions handle the types of the parameters that you pass in?

Python is strongly typed because every object has a type, every object knows its type, it's impossible to accidentally or deliberately use an object of a type "as if" it was an object of a different type, and all elementary operations on the object are delegated to its type.

This has nothing to do with names. A name in Python doesn't "have a type": if and when a name's defined, the name refers to an object, and the object does have a type (but that doesn't in fact force a type on the name: a name is a name).

A name in Python can perfectly well refer to different objects at different times (as in most programming languages, though not all) -- and there is no constraint on the name such that, if it has once referred to an object of type X, it's then forevermore constrained to refer only to other objects of type X. Constraints on names are not part of the concept of "strong typing", though some enthusiasts of static typing (where names do get constrained, and in a static, AKA compile-time, fashion, too) do misuse the term this way.

PHP create key => value pairs within a foreach

Create key value pairs on the phpsh commandline like this:

php> $keyvalues = array();
php> $keyvalues['foo'] = "bar";
php> $keyvalues['pyramid'] = "power";
php> print_r($keyvalues);
    [foo] => bar
    [pyramid] => power

Get the count of key value pairs:

php> echo count($offerarray);

Get the keys as an array:

php> echo implode(array_keys($offerarray));

How to call a vue.js function on page load

If you get data in array you can do like below. It's worked for me

    {{ id }}

    import axios from "axios";

        export default {
            name: 'HelloWorld',
            data () {
                return {
                    id: "",

    mounted() {
                axios({ method: "GET", "url": "https://localhost:42/api/getdata" }).then(result => {
                }, error => {

How to merge remote changes at GitHub?

You can also force a push by adding the + symbol before your branch name.

git push origin +some_branch

Library not loaded: libmysqlclient.16.dylib error when trying to run 'rails server' on OS X 10.6 with mysql2 gem

I've had this exact same problem a few days ago. I eventually managed to solve it. I'm not quite sure how, but I'll tell you what I did anyway. Maybe it'll help you.

I started by downloading RVM. If you aren't using it yet, I highly recommend doing so. It basically creates a sandbox for a new separate installation of Ruby, RoR and RubyGems. In fact, you can have multiple installations simultaneously and instantly switch to one other. It works like a charm.

Why is this useful? Because you shouldn't mess with the default Ruby installation in OS X. The system depends on it. It's best to just leave the default Ruby and RoR installation alone and create a new one using RVM that you can use for your own development.

Once I created my separate Ruby installation, I just installed RoR, RubyGems and mysql, and it worked. For the exact steps I took, see my question: Installing Rails, MySQL, etc. everything goes wrong

Again: I don't know for certain this will solve your problem. But it certainly did the trick for me, and in any case using RVM is highly recommendable.


what may be happening is your company decrypts certain traffic and re-encrypts it with their certificate (which you probably already have in your keychain or trusted root certificates)

if you're using node 7 or later I've found this fix to be compatible with node and node-gyp (for Windows you'll need to do this differently, but you basically just need to add this environment variable):

export NODE_EXTRA_CA_CERTS="absolute_path_to_your_certificates.pem" (in Windows you may need to remove the quotes - see comments)

the pem file can have multiple certificates:

make sure your certificates are in proper pem format (you need real line breaks not literal \n)

I couldn't seem to get it to work with relative paths (. or ~)

This fix basically tells npm and node-gyp to use the check against the regular CAs, but also allow this certificate when it comes across it

Ideally you would be able to use your system's trusted certificates, but unfortunately this is not the case.

How to programmatically set the layout_align_parent_right attribute of a Button in Relative Layout?

You can access any LayoutParams from code using View.getLayoutParams. You just have to be very aware of what LayoutParams your accessing. This is normally achieved by checking the containing ViewGroup if it has a LayoutParams inner child then that's the one you should use. In your case it's RelativeLayout.LayoutParams. You'll be using RelativeLayout.LayoutParams#addRule(int verb) and RelativeLayout.LayoutParams#addRule(int verb, int anchor)

You can get to it via code:

RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams)button.getLayoutParams();

button.setLayoutParams(params); //causes layout update

C++ delete vector, objects, free memory

if I use the clear() member function. Can I be sure that the memory was released?

No, the clear() member function destroys every object contained in the vector, but it leaves the capacity of the vector unchanged. It affects the vector's size, but not the capacity.

If you want to change the capacity of a vector, you can use the clear-and-minimize idiom, i.e., create a (temporary) empty vector and then swap both vectors.

You can easily see how each approach affects capacity. Consider the following function template that calls the clear() member function on the passed vector:

template<typename T>
auto clear(std::vector<T>& vec) {
   return vec.capacity();

Now, consider the function template empty_swap() that swaps the passed vector with an empty one:

template<typename T>
auto empty_swap(std::vector<T>& vec) {
   return vec.capacity();

Both function templates return the capacity of the vector at the moment of returning, then:

std::vector<double> v(1000), u(1000);
std::cout << clear(v) << '\n';
std::cout << empty_swap(u) << '\n';



Is there an equivalent to CTRL+C in IPython Notebook in Firefox to break cells that are running?

I could be wrong, but I'm pretty sure that the "interrupt kernel" button just sends a SIGINT signal to the code that you're currently running (this idea is supported by Fernando's comment here), which is the same thing that hitting CTRL+C would do. Some processes within python handle SIGINTs more abruptly than others.

If you desperately need to stop something that is running in iPython Notebook and you started iPython Notebook from a terminal, you can hit CTRL+C twice in that terminal to interrupt the entire iPython Notebook server. This will stop iPython Notebook alltogether, which means it won't be possible to restart or save your work, so this is obviously not a great solution (you need to hit CTRL+C twice because it's a safety feature so that people don't do it by accident). In case of emergency, however, it generally kills the process more quickly than the "interrupt kernel" button.

How to Load RSA Private Key From File

Two things. First, you must base64 decode the mykey.pem file yourself. Second, the openssl private key format is specified in PKCS#1 as the RSAPrivateKey ASN.1 structure. It is not compatible with java's PKCS8EncodedKeySpec, which is based on the SubjectPublicKeyInfo ASN.1 structure. If you are willing to use the bouncycastle library you can use a few classes in the bouncycastle provider and bouncycastle PKIX libraries to make quick work of this.


import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openssl.PEMKeyPair;
import org.bouncycastle.openssl.PEMParser;
import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter;

// ...   

String keyPath = "mykey.pem";
BufferedReader br = new BufferedReader(new FileReader(keyPath));
Security.addProvider(new BouncyCastleProvider());
PEMParser pp = new PEMParser(br);
PEMKeyPair pemKeyPair = (PEMKeyPair) pp.readObject();
KeyPair kp = new JcaPEMKeyConverter().getKeyPair(pemKeyPair);
samlResponse.sign(Signature.getInstance("SHA1withRSA").toString(), kp.getPrivate(), certs);

Oracle SQL: Use sequence in insert with Select Statement

Assuming that you want to group the data before you generate the key with the sequence, it sounds like you want something like

SELECT MY_SEQ.nextval,
  FROM (SELECT '2010' year,
               '12' month,
               'ALL' make,
               'ALL' model,
               sum(AVG_MSRP*COUNT)/sum(COUNT) avg_msrp,
               sum(cnt) cnt
         WHERE YEAR = '2010' 
           AND MONTH = '12'
           AND MAKE != 'ALL' 

How can I create download link in HTML?

The download attribute is new for the <a> tag in HTML5

<a href="" download>Download Form</a>
<a href="" download="Form">Download Form</a>

I prefer the first one it is preferable in respect to any extension.