Programs & Examples On #Fpdi

A PHP class which allows to read pages from existing PDF and generate new files based on FPDF.

How to set env variable in Jupyter notebook

You can also set the variables in your kernel.json file:

My solution is useful if you need the same environment variables every time you start a jupyter kernel, especially if you have multiple sets of environment variables for different tasks.

To create a new ipython kernel with your environment variables, do the following:

  • Read the documentation at
  • Run jupyter kernelspec list to see a list with installed kernels and where the files are stored.
  • Copy the directory that contains the kernel.json (e.g. named python2) to a new directory (e.g. python2_myENV).
  • Change the display_name in the new kernel.json file.
  • Add a env dictionary defining the environment variables.

Your kernel json could look like this (I did not modify anything from the installed kernel.json except display_name and env):

 "display_name": "Python 2 with environment",
 "language": "python",
 "argv": [
 "env": {"LD_LIBRARY_PATH":""}

Use cases and advantages of this approach

  • In my use-case, I wanted to set the variable LD_LIBRARY_PATH which effects how compiled modules (e.g. written in C) are loaded. Setting this variable using %set_env did not work.
  • I can have multiple python kernels with different environments.
  • To change the environment, I only have to switch/ restart the kernel, but I do not have to restart the jupyter instance (useful, if I do not want to loose the variables in another notebook). See -however -

Typescript - multidimensional array initialization

You only need [] to instantiate an array - this is true regardless of its type. The fact that the array is of an array type is immaterial.

The same thing applies at the first level in your loop. It is merely an array and [] is a new empty array - job done.

As for the second level, if Thing is a class then new Thing() will be just fine. Otherwise, depending on the type, you may need a factory function or other expression to create one.

class Something {
    private things: Thing[][];

    constructor() {
        this.things = [];

        for(var i: number = 0; i < 10; i++) {
            this.things[i] = [];
            for(var j: number = 0; j< 10; j++) {
                this.things[i][j] = new Thing();

Data access object (DAO) in Java


It is a object/interface, which is used to access data from database of data storage.


it abstracts the retrieval of data from a data resource such as a database. The concept is to "separate a data resource's client interface from its data access mechanism."

The problem with accessing data directly is that the source of the data can change. Consider, for example, that your application is deployed in an environment that accesses an Oracle database. Then it is subsequently deployed to an environment that uses Microsoft SQL Server. If your application uses stored procedures and database-specific code (such as generating a number sequence), how do you handle that in your application? You have two options:

  • Rewrite your application to use SQL Server instead of Oracle (or add conditional code to handle the differences), or
  • Create a layer inbetween your application logic and the data access

Its in all referred as DAO Pattern, It consist of following:

  • Data Access Object Interface - This interface defines the standard operations to be performed on a model object(s).
  • Data Access Object concrete class -This class implements above interface. This class is responsible to get data from a datasource which can be database / xml or any other storage mechanism.
  • Model Object or Value Object - This object is simple POJO containing get/set methods to store data retrieved using DAO class.

Please check this example, This will clear things more clearly.

I assume this things must have cleared your understanding of DAO up to certain extend.

Efficiently updating database using SQLAlchemy ORM

If it is because of the overhead in terms of creating objects, then it probably can't be sped up at all with SA.

If it is because it is loading up related objects, then you might be able to do something with lazy loading. Are there lots of objects being created due to references? (IE, getting a Company object also gets all of the related People objects).

How to create a zip archive of a directory in Python?

I've made some changes to code given by Mark Byers. Below function will also adds empty directories if you have them. Examples should make it more clear what is the path added to the zip.

#!/usr/bin/env python
import os
import zipfile

def addDirToZip(zipHandle, path, basePath=""):
    Adding directory given by \a path to opened zip file \a zipHandle

    @param basePath path that will be removed from \a path when adding to archive

        # add whole "dir" to "" (when you open "" you will see only "dir")
        zipHandle = zipfile.ZipFile('', 'w')
        addDirToZip(zipHandle, 'dir')

        # add contents of "dir" to "" (when you open "" you will see only it's contents)
        zipHandle = zipfile.ZipFile('', 'w')
        addDirToZip(zipHandle, 'dir', 'dir')

        # add contents of "dir/subdir" to "" (when you open "" you will see only contents of "subdir")
        zipHandle = zipfile.ZipFile('', 'w')
        addDirToZip(zipHandle, 'dir/subdir', 'dir/subdir')

        # add whole "dir/subdir" to "" (when you open "" you will see only "subdir")
        zipHandle = zipfile.ZipFile('', 'w')
        addDirToZip(zipHandle, 'dir/subdir', 'dir')

        # add whole "dir/subdir" with full path to "" (when you open "" you will see only "dir" and inside it only "subdir")
        zipHandle = zipfile.ZipFile('', 'w')
        addDirToZip(zipHandle, 'dir/subdir')

        # add whole "dir" and "otherDir" (with full path) to "" (when you open "" you will see only "dir" and "otherDir")
        zipHandle = zipfile.ZipFile('', 'w')
        addDirToZip(zipHandle, 'dir')
        addDirToZip(zipHandle, 'otherDir')
    basePath = basePath.rstrip("\\/") + ""
    basePath = basePath.rstrip("\\/")
    for root, dirs, files in os.walk(path):
        # add dir itself (needed for empty dirs
        zipHandle.write(os.path.join(root, "."))
        # add files
        for file in files:
            filePath = os.path.join(root, file)
            inZipPath = filePath.replace(basePath, "", 1).lstrip("\\/")
            #print filePath + " , " + inZipPath
            zipHandle.write(filePath, inZipPath)

Above is a simple function that should work for simple cases. You can find more elegant class in my Gist:

Environment variable to control

If you look in the source code of the JDK, you can see that for unix systems the property is read at compile time from the paths.h or hard coded. For windows the function GetTempPathW from win32 returns the tmpdir name.

For posix systems you might expect the standard TMPDIR to work, but that is not the case. You can confirm that TMPDIR is not used by running TMPDIR=/mytmp java -XshowSettings

Android Split string

.split method will work, but it uses regular expressions. In this example it would be (to steal from Cristian):

String[] separated = CurrentString.split("\\:");
separated[0]; // this will contain "Fruit"
separated[1]; // this will contain " they taste good"

Also, this came from: Android split not working correctly

Progress Bar with HTML and CSS

There is a tutorial for creating an HTML5 progress bar here. If you don't want to use HTML5 methods or you are looking for an all-browser solution, try this code:

<div style="width: 150px; height: 25px; background-color: #dbdbdb;">
  <div style="height: 25px; width:87%; background-color: gold">&nbsp;</div>

You can change the color GOLD to any progress bar color and #dbdbdb to the background-color of your progress bar.

How can I temporarily disable a foreign key constraint in MySQL?

To turn off the foreign key constraint globally:


And for the active foreign key constraint:


Spring Boot Configure and Use Two DataSources

I used mybatis - springboot 2.0 tech stack, solution:

// - start
    sp.ds1.validationQuery=SELECT 1

    sp.ds2.validationQuery=SELECT 1

// - end

//configuration class

    @ComponentScan(basePackages = "com.mypkg")
    public class MultipleDBConfig {

        public static final String SQL_SESSION_FACTORY_NAME_1 = "sqlSessionFactory1";
        public static final String SQL_SESSION_FACTORY_NAME_2 = "sqlSessionFactory2";

        public static final String MAPPERS_PACKAGE_NAME_1 = "com.mypg.mymapper1";
        public static final String MAPPERS_PACKAGE_NAME_2 = "com.mypg.mymapper2";

        @Bean(name = "mysqlDb1")
        @ConfigurationProperties(prefix = "sp.ds1")
        public DataSource dataSource1() {
            System.out.println("db1 datasource");
            return DataSourceBuilder.create().build();

        @Bean(name = "mysqlDb2")
        @ConfigurationProperties(prefix = "sp.ds2")
        public DataSource dataSource2() {
            System.out.println("db2 datasource");
            return  DataSourceBuilder.create().build();

        @Bean(name = SQL_SESSION_FACTORY_NAME_1)
        public SqlSessionFactory sqlSessionFactory1(@Qualifier("mysqlDb1") DataSource dataSource1) throws Exception {
            SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
            SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBean.getObject();
            return sqlSessionFactory;

        @Bean(name = SQL_SESSION_FACTORY_NAME_2)
        public SqlSessionFactory sqlSessionFactory2(@Qualifier("mysqlDb2") DataSource dataSource2) throws Exception {
            SqlSessionFactoryBean diSqlSessionFactoryBean = new SqlSessionFactoryBean();
            SqlSessionFactory sqlSessionFactory = diSqlSessionFactoryBean.getObject();
            return sqlSessionFactory;

        public MapperScannerConfigurer mapperScannerConfigurer1() {
            MapperScannerConfigurer configurer = new MapperScannerConfigurer();
            return configurer;

        public MapperScannerConfigurer mapperScannerConfigurer2() {
            MapperScannerConfigurer configurer = new MapperScannerConfigurer();
            return configurer;


Note : 1)@Primary -> @primary

2)---."jdbc-url" in properties -> After Spring Boot 2.0 migration: jdbcUrl is required with driverClassName

Building and running app via Gradle and Android Studio is slower than via Eclipse

USE this sudo dpkg --add-architecture i386 sudo apt-get update sudo apt-get install libncurses5:i386 libstdc++6:i386 zlib1g:i386

Android Studio fails to build new project, timed out while wating for slave aapt process

Push items into mongo array via mongoose

Use $push to update document and insert new value inside an array.



result for find:

    "_id" : ObjectId("5bc061f05a4c0511a9252e88"),
    "count" : 1.0,
    "color" : "green",
    "icon" : "circle",
    "graph" : [ 
            "date" : ISODate("2018-10-24T08:55:13.331Z"),
            "count" : 2.0
    "name" : "online visitor",
    "read" : false,
    "date" : ISODate("2018-10-12T08:57:20.853Z"),
    "__v" : 0.0


   { _id: ObjectId("5bc061f05a4c0511a9252e88") }, 
   { $push: { 
             graph: {
               "date" : ISODate("2018-10-24T08:55:13.331Z"),
               "count" : 3.0

result for update:

    "_id" : ObjectId("5bc061f05a4c0511a9252e88"),
    "count" : 1.0,
    "color" : "green",
    "icon" : "circle",
    "graph" : [ 
            "date" : ISODate("2018-10-24T08:55:13.331Z"),
            "count" : 2.0
            "date" : ISODate("2018-10-24T08:55:13.331Z"),
            "count" : 3.0
    "name" : "online visitor",
    "read" : false,
    "date" : ISODate("2018-10-12T08:57:20.853Z"),
    "__v" : 0.0

Re-order columns of table in Oracle

It's sad that Oracle doesn't allow this, I get asked to do this by developers all the time..

Here's a slightly dangerous, somewhat quick and dirty method:

  1. Ensure you have enough space to copy the Table
  2. Note any Constraints, Grants, Indexes, Synonyms, Triggers, um.. maybe some other stuff - that belongs to a Table - that I haven't thought about?
  3. CREATE TABLE table_right_columns AS SELECT column1 column3, column2 FROM table_wrong_columns; -- Notice how we correct the position of the columns :)
  4. DROP TABLE table_wrong_columns;
  5. 'ALTER TABLE table_right_columns RENAME TO table_wrong_columns;`
  6. Now the yucky part: recreate all those items you noted in step 2 above
  7. Check what code is now invalid, and recompile to check for errors

And next time you create a table, please consider the future requirements! ;)

"Permission Denied" trying to run Python on Windows 10

Simple answer: replace python with PY everything will work as expected

"Field has incomplete type" error

The problem is that your ui property uses a forward declaration of class Ui::MainWindowClass, hence the "incomplete type" error.

Including the header file in which this class is declared will fix the problem.


Based on your comment, the following code:

namespace Ui
    class MainWindowClass;

does NOT declare a class. It's a forward declaration, meaning that the class will exist at some point, at link time.
Basically, it just tells the compiler that the type will exist, and that it shouldn't warn about it.

But the class has to be defined somewhere.

Note this can only work if you have a pointer to such a type.
You can't have a statically allocated instance of an incomplete type.

So either you actually want an incomplete type, and then you should declare your ui member as a pointer:

namespace Ui
    // Forward declaration - Class will have to exist at link time
    class MainWindowClass;

class MainWindow : public QMainWindow

        // Member needs to be a pointer, as it's an incomplete type
        Ui::MainWindowClass * ui;

Or you want a statically allocated instance of Ui::MainWindowClass, and then it needs to be declared. You can do it in another header file (usually, there's one header file per class).
But simply changing the code to:

namespace Ui
    // Real class declaration - May/Should be in a specific header file
    class MainWindowClass

class MainWindow : public QMainWindow

        // Member can be statically allocated, as the type is complete
        Ui::MainWindowClass ui;

will also work.

Note the difference between the two declarations. First uses a forward declaration, while the second one actually declares the class (here with no properties nor methods).

Passing multiple values for a single parameter in Reporting Services

Although John Sansom's solution works, there's another way to do this, without having to use a potentially inefficient scalar valued UDF. In the SSRS report, on the parameters tab of the query definition, set the parameter value to

=join(Parameters!<your param name>.Value,",")

In your query, you can then reference the value like so:

where yourColumn in (@<your param name>)

How to delete an SVN project from SVN repository

In the case where you simply want to delete a project from the head revision, so that it no longer shows up in your repo when you run svn list file:///path/to/repo/ just run:

svn delete file:///path/to/repo/project 

However, if you need to delete all record of it in the repo, use another method.

Inverse of matrix in R

solve(c) does give the correct inverse. The issue with your code is that you are using the wrong operator for matrix multiplication. You should use solve(c) %*% c to invoke matrix multiplication in R.

R performs element by element multiplication when you invoke solve(c) * c.

How to 'insert if not exists' in MySQL?

Any simple constraint should do the job, if an exception is acceptable. Examples :

  • primary key if not surrogate
  • unique constraint on a column
  • multi-column unique constraint

Sorry is this seems deceptively simple. I know it looks bad confronted to the link you share with us. ;-(

But I neverleless give this answer, because it seem to fill your need. (If not, it may trigger your updating your requirements, which would be "a Good Thing"(TM) also).

Edited: If an insert would break the database unique constraint, an exception is throw at the database level, relayed by the driver. It will certainly stop your script, with a failure. It must be possible in PHP to adress that case ...

Delete all Duplicate Rows except for One in MySQL?

If you want to keep the row with the lowest id value:

                    FROM (SELECT MIN(
                            FROM NAMES n
                        GROUP BY x)

If you want the id value that is the highest:

                    FROM (SELECT MAX(
                            FROM NAMES n
                        GROUP BY x)

The subquery in a subquery is necessary for MySQL, or you'll get a 1093 error.

Bootstrap 3.0 - Fluid Grid that includes Fixed Column Sizes

edit: As lots of people seem to want to do this, I have written up a short guide with a more general use case here Hope it helps.

The bootstrap3 grid system supports row nesting which allows you to adjust the root row to allow fixed width side menus.

You need to put in a padding-left on the root row, then have a child row which contains your normal grid layout elements.

Here is how I usually do this


<div class="container">
    <div class="row">
        <div class="col-fixed-240">Fixed 240px</div>
        <div class="col-fixed-160">Fixed 160px</div>
        <div class="col-md-12 col-offset-400">
            <div class="row">
            Standard grid system content here





Is it possible to hide/encode/encrypt php source code and let others have the system?

There are many ways for doing that (you might want to obfuscate the source code, you can compress it, ...). Some of these methods need additional code to transform your program in an executable form (compression, for example).

But the thing all methods cannot do, is keeping the source code secret. The other party gets your binary code, which can always be transformed (reverse-engineered) into a human-readable form again, because the binary code contains all functionality information that is provided in your source code.

Spring Maven clean error - The requested profile "pom.xml" could not be activated because it does not exist

Goto Properties -> maven Remove the pom.xml from the activate profiles and follow the below steps.

Steps :

  1. Delete the .m2 repository
  2. Restart the Eclipse IDE
  3. Refresh and Rebuild it

PHP Fatal error: Class 'PDO' not found

I had to run the following on AWS EC2 Linux instance (PHP Version 7.3):

sudo yum install php73-php-pdo php73-php-mysqlnd

Effect of using sys.path.insert(0, path) and sys.path(append) when loading modules

I'm quite a beginner in Python and I found the answer of Anand was very good but quite complicated to me, so I try to reformulate :

1) insert and append methods are not specific to sys.path and as in other languages they add an item into a list or array and :
* append(item) add item to the end of the list,
* insert(n, item) inserts the item at the nth position in the list (0 at the beginning, 1 after the first element, etc ...).

2) As Anand said, python search the import files in each directory of the path in the order of the path, so :
* If you have no file name collisions, the order of the path has no impact,
* If you look after a function already defined in the path and you use append to add your path, you will not get your function but the predefined one.

But I think that it is better to use append and not insert to not overload the standard behaviour of Python, and use non-ambiguous names for your files and methods.

How to get the previous page URL using JavaScript?

You can use the following to get the previous URL.

var oldURL = document.referrer;

No input file specified

In my case, there were an error in the php.ini open_basedir variable.

Cannot instantiate the type List<Product>

List is an interface. Interfaces cannot be instantiated. Only concrete types can be instantiated. You probably want to use an ArrayList, which is an implementation of the List interface.

List<Product> products = new ArrayList<Product>();

Simple way to transpose columns and rows in SQL?

There are several ways that you can transform this data. In your original post, you stated that PIVOT seems too complex for this scenario, but it can be applied very easily using both the UNPIVOT and PIVOT functions in SQL Server.

However, if you do not have access to those functions this can be replicated using UNION ALL to UNPIVOT and then an aggregate function with a CASE statement to PIVOT:

Create Table:

CREATE TABLE yourTable([color] varchar(5), [Paul] int, [John] int, [Tim] int, [Eric] int);

    ([color], [Paul], [John], [Tim], [Eric])
    ('Red', 1, 5, 1, 3),
    ('Green', 8, 4, 3, 5),
    ('Blue', 2, 2, 9, 1);

Union All, Aggregate and CASE Version:

select name,
  sum(case when color = 'Red' then value else 0 end) Red,
  sum(case when color = 'Green' then value else 0 end) Green,
  sum(case when color = 'Blue' then value else 0 end) Blue
  select color, Paul value, 'Paul' name
  from yourTable
  union all
  select color, John value, 'John' name
  from yourTable
  union all
  select color, Tim value, 'Tim' name
  from yourTable
  union all
  select color, Eric value, 'Eric' name
  from yourTable
) src
group by name

See SQL Fiddle with Demo

The UNION ALL performs the UNPIVOT of the data by transforming the columns Paul, John, Tim, Eric into separate rows. Then you apply the aggregate function sum() with the case statement to get the new columns for each color.

Unpivot and Pivot Static Version:

Both the UNPIVOT and PIVOT functions in SQL server make this transformation much easier. If you know all of the values that you want to transform, you can hard-code them into a static version to get the result:

select name, [Red], [Green], [Blue]
  select color, name, value
  from yourtable
    value for name in (Paul, John, Tim, Eric)
  ) unpiv
) src
  for color in ([Red], [Green], [Blue])
) piv

See SQL Fiddle with Demo

The inner query with the UNPIVOT performs the same function as the UNION ALL. It takes the list of columns and turns it into rows, the PIVOT then performs the final transformation into columns.

Dynamic Pivot Version:

If you have an unknown number of columns (Paul, John, Tim, Eric in your example) and then an unknown number of colors to transform you can use dynamic sql to generate the list to UNPIVOT and then PIVOT:

    @query  AS NVARCHAR(MAX),
    @colsPivot as  NVARCHAR(MAX)

select @colsUnpivot = stuff((select ','+quotename(
         from sys.columns as C
         where C.object_id = object_id('yourtable') and
      <> 'color'
         for xml path('')), 1, 1, '')

select @colsPivot = STUFF((SELECT  ',' 
                      + quotename(color)
                    from yourtable t
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 

set @query 
  = 'select name, '+@colsPivot+'
        select color, name, value
        from yourtable
          value for name in ('+@colsUnpivot+')
        ) unpiv
      ) src
        for color in ('+@colsPivot+')
      ) piv'


See SQL Fiddle with Demo

The dynamic version queries both yourtable and then the sys.columns table to generate the list of items to UNPIVOT and PIVOT. This is then added to a query string to be executed. The plus of the dynamic version is if you have a changing list of colors and/or names this will generate the list at run-time.

All three queries will produce the same result:

| Eric |   3 |     5 |    1 |
| John |   5 |     4 |    2 |
| Paul |   1 |     8 |    2 |
|  Tim |   1 |     3 |    9 |

Sending an HTTP POST request on iOS

-(void)sendingAnHTTPPOSTRequestOniOSWithUserEmailId: (NSString *)emailId withPassword: (NSString *)password{
//Init the NSURLSession with a configuration
NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: nil delegateQueue: [NSOperationQueue mainQueue]];

//Create an URLRequest
NSURL *url = [NSURL URLWithString:@""];
NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:url];

//Create POST Params and add it to HTTPBody
NSString *params = [NSString stringWithFormat:@"email=%@&password=%@",emailId,password];
[urlRequest setHTTPMethod:@"POST"];
[urlRequest setHTTPBody:[params dataUsingEncoding:NSUTF8StringEncoding]];

//Create task
NSURLSessionDataTask *dataTask = [defaultSession dataTaskWithRequest:urlRequest completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
    //Handle your response here
    NSDictionary *responseDict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
   [dataTask resume];

Understanding the Gemfile.lock file

Bundler is a Gem manager which provides a consistent environment for Ruby projects by tracking and installing the exact gems and versions that are needed.

Gemfile and Gemfile.lock are primary products given by Bundler gem (Bundler itself is a gem).

Gemfile contains your project dependency on gem(s), that you manually mention with version(s) specified, but those gem(s) inturn depends on other gem(s) which is resolved by bundler automatically.

Gemfile.lock contain complete snapshot of all the gem(s) in Gemfile along with there associated dependency.

When you first call bundle install, it will create this Gemfile.lock and uses this file in all subsequent calls to bundle install, which ensures that you have all the dependencies installed and will skip dependency installation.

Same happens when you share your code with different machines

You share your Gemfile.lock along with Gemfile, when you run bundle install on other machine it will refer to your Gemfile.lock and skip dependency resolution step, instead it will install all of the same dependent gem(s) that you used on the original machine, which maintains consistency across multiple machines

Why do we need to maintain consistency along multiple machines ?

  • Running different versions on different machines could lead to broken code

  • Suppose, your app used the version 1.5.3 and it works 14 months ago
    without any problems, and you try to install on different machine
    without Gemfile.lock now you get the version 1.5.8. Maybe it's broken with the latest version of some gem(s) and your application will
    fail. Maintaining consistency is of utmost importance (preferred

It is also possible to update gem(s) in Gemfile.lock by using bundle update.

This is based on the concept of conservative updating

How to read user input into a variable in Bash?

Use read -p:

# fullname="USER INPUT"
read -p "Enter fullname: " fullname
# user="USER INPUT"
read -p "Enter user: " user

If you like to confirm:

read -p "Continue? (Y/N): " confirm && [[ $confirm == [yY] || $confirm == [yY][eE][sS] ]] || exit 1

You should also quote your variables to prevent pathname expansion and word splitting with spaces:

# passwd "$user"
# mkdir "$home"
# chown "$user:$group" "$home"

How do you format an unsigned long long int using printf?

Apparently no one has come up with a multi-platform* solution for over a decade since [the] year 2008, so I shall append mine . Plz upvote. (Joking. I don’t care.)

Solution: lltoa()

How to use:

#include <stdlib.h> /* lltoa() */
// ...
char dummy[255];
printf("Over 4 bytes: %s\n", lltoa(5555555555, dummy, 10));
printf("Another one: %s\n", lltoa(15555555555, dummy, 10));

OP’s example:

#include <stdio.h>
#include <stdlib.h> /* lltoa() */

int main() {
    unsigned long long int num = 285212672; // fits in 29 bits
    char dummy[255];
    int normalInt = 5;
    printf("My number is %d bytes wide and its value is %s. "
        "A normal number is %d.\n", 
        sizeof(num), lltoa(num, dummy, 10), normalInt);
    return 0;

Unlike the %lld print format string, this one works for me under 32-bit GCC on Windows.

*) Well, almost multi-platform. In MSVC, you apparently need _ui64toa() instead of lltoa().

Ant error when trying to build file, can't find tools.jar?

Just set your java_home property with java home (eg:C:\Program Files\Java\jdk1.7.0_25) directory. Close command prompt and reopen it. Then error relating to tools.jar will be solved. For the second one("build.xml not found ") you should have to ensure your command line also at the directory where your build.xml file resides.

How to convert an address to a latitude/longitude?

Google has a geocoding API which seems to work pretty well for most of the locations that they have Google Maps data for.

They provide online geocoding (via JavaScript):

Or backend geocoding (via an HTTP request):

The data is usually the same used by Google Maps itself. (note that there are some exceptions to this, such as the UK or Israel, where the data is from a different source and of slightly reduced quality)

Laravel Redirect Back with() Message

in controller

For example

return redirect('login')->with('message',$message);

in blade file The message will store in session not in variable.

For example

{{ session('message') }}

ResourceDictionary in a separate assembly

I'm working with .NET 4.5 and couldn't get this working... I was using WPF Custom Control Library. This worked for me in the end...

<ResourceDictionary Source="/MyAssembly;component/mytheme.xaml" />


How to switch from the default ConstraintLayout to RelativeLayout in Android Studio

  1. Right click on ConstraintLayout.
  2. Select convertview.
  3. select RelativeLayout

For more clarity refer below image

enter image description here

Import Android volley to Android Studio

Updating Warpzit's answer for Android Studio 1.3.2 (differences in bold)
(update: appears to be the same for Android 2.0)

  1. First get latest volley with git.
  2. In your current project (android studio) click [file] --> [New]--> [New Module].
  3. Now select [Import Gradle Project], Click Next
  4. Now select the directory where you downloaded Volley to.
  5. Now Android studio might guide you to do the rest but continue guide to verify that everything works correct
  6. Open settings.gradle (find in root) and add (or verify this is included):

    include ':app', ':volley'

  7. Now go to your build.gradle in your project and add the dependency:

    compile project(":volley")

Mac zip compress without __MACOSX folder?

The zip command line utility never creates a __MACOSX directory, so you can just run a command like this:

zip -x \*.DS_Store -r directory

In the output below, which I created with the zip command line utility does not contain a __MACOSX directory, but a which I created from Finder does.

$ touch a
$ xattr -w somekey somevalue a
$ zip a
  adding: a (stored 0%)
$ unzip -l
  Length     Date   Time    Name
 --------    ----   ----    ----
        0  01-02-16 20:29   a
 --------                   -------
        0                   1 file
$ unzip -l a\ # I created `a` from Finder before this
Archive:  a
  Length     Date   Time    Name
 --------    ----   ----    ----
        0  01-02-16 20:29   a
        0  01-02-16 20:31   __MACOSX/
      149  01-02-16 20:29   __MACOSX/._a
 --------                   -------
      149                   3 files

-x .DS_Store does not exclude .DS_Store files inside directories but -x \*.DS_Store does.

The top level file of a zip archive with multiple files should usually be a single directory, because if it is not, some unarchiving utilites (like unzip and 7z, but not Archive Utility, The Unarchiver, unar, or dtrx) do not create a containing directory for the files when the archive is extracted, which often makes the files difficult to find, and if multiple archives like that are extracted at the same time, it can be difficult to tell which files belong to which archive.

Archive Utility only creates a __MACOSX directory when you create an archive where at least one file contains metadata such as extended attributes, file flags, or a resource fork. The __MACOSX directory contains AppleDouble files whose filename starts with ._ that are used to store OS X-specific metadata. The zip command line utility discards metadata such as extended attributes, file flags, and resource forks, which also means that metadata such as tags is lost, and that aliases stop working, because the information in an alias file is stored in a resource fork.

Normally you can just discard the OS X-specific metadata, but to see what metadata files contain, you can use xattr -l. xattr also includes resource forks and file flags, because even though they are not actually stored as extended attributes, they can be accessed through the extended attributes interface. Both Archive Utility and the zip command line utility discard ACLs.

Why use #ifndef CLASS_H and #define CLASS_H in .h file but not in .cpp?

It is generally expected that modules of code such as .cpp files are compiled once and linked to in multiple projects, to avoid unnecessary repetitive compilation of logic. For example, g++ -o class.cpp would produce class.o which you could then link from multiple projects to using g++ main.cpp class.o.

We could use #include as our linker, as you seem to be implying, but that would just be silly when we know how to link properly using our compiler with less keystrokes and less wasteful repetition of compilation, rather than our code with more keystrokes and more wasteful repetition of compilation...

The header files are still required to be included into each of the multiple projects, however, because this provides the interface for each module. Without these headers the compiler wouldn't know about any of the symbols introduced by the .o files.

It is important to realise that the header files are what introduce the definitions of symbols for those modules; once that is realised then it makes sense that multiple inclusions could cause redefinitions of symbols (which causes errors), so we use include guards to prevent such redefinitions.

What is the difference between Cloud, Grid and Cluster?

Cloud: is simply an aggregate of computing power. You can think of the entire "cloud" as single server, for your purposes. It's conceptually much like an old school mainframe where you could submit your jobs to and have it return the result, except that nowadays the concept is applied more widely. (I.e. not just raw computing, also entire services, or storage ...)

Grid: a grid is simply many computers which together might solve a given problem/crunch data. The fundamental difference between a grid and a cluster is that in a grid each node is relatively independent of others; problems are solved in a divide and conquer fashion.

Cluster: conceptually it is essentially smashing up many machines to make a really big & powerful one. This is a much more difficult architecture than cloud or grid to get right because you have to orchestrate all nodes to work together, and provide consistency of things such as cache, memory, and not to mention clocks. Of course clouds have much the same problem, but unlike clusters clouds are not conceptually one big machine, so the entire architecture doesn't have to treat it as such. You can for instance not allocate the full capacity of your data center to a single request, whereas that is kind of the point of a cluster: to be able to throw 100% of the oomph at a single problem.

Check if checkbox is NOT checked on click - jQuery

jQuery to check for checked? Really?

if(!this.checked) {

Don't use a bazooka to do a razor's job.

How to make a boolean variable switch between true and false every time a method is invoked?

value ^= true;

That is value xor-equals true, which will flip it every time, and without any branching or temporary variables.

How to playback MKV video in web browser?

You can use this following code. work just on chrome browser.

 function failed(e) {_x000D_
   // video playback failed - show a message saying why_x000D_
   switch ( {_x000D_
       alert('You aborted the video playback.');_x000D_
       alert('A network error caused the video download to fail part-way.');_x000D_
       alert('The video playback was aborted due to a corruption problem or because the video used features your browser did not support.');_x000D_
       alert('The video could not be loaded, either because the server or network failed or because the format is not supported.');_x000D_
       alert('An unknown error occurred.');_x000D_
 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">_x000D_
<html xmlns="" xml:lang="en" lang="en">_x000D_
 <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />_x000D_
 <meta name="author" content="Amin Developer!" />_x000D_
 <title>Untitled 1</title>_x000D_
<p><video src="" type='video/x-matroska; codecs="theora, vorbis"' autoplay controls onerror="failed(event)" ></video></p>_x000D_
<p><a href="YOU mkv FILE LINK GOES HERE TO DOWNLOAD">Download the video file</a>.</p>_x000D_

failed to resolve and

I had such dependancy in build.gradle -

compile ''

But it causes unstable builds. Ensure it works ok for you, and look in your android sdk manager for current version of support lib available, and replace this dependency with

def final RECYCLER_VIEW_VER = '23.1.1'
compile "${RECYCLER_VIEW_VER}"

How to ignore files/directories in TFS for avoiding them to go to central source repository?

For VS2015 and VS2017

Works with TFS (on-prem) or VSO (Visual Studio Online - the Azure-hosted offering)

The NuGet documentation provides instructions on how to accomplish this and I just followed them successfully for Visual Studio 2015 & Visual Studio 2017 against VSTS (Azure-hosted TFS). Everything is fully updated as of Nov 2016 Aug 2018.

I recommend you follow NuGet's instructions but just to recap what I did:

  1. Make sure your packages folder is not committed to TFS. If it is, get it out of there.
  2. Everything else we create below goes into the same folder that your .sln file exists in unless otherwise specified (NuGet's instructions aren't completely clear on this).
  3. Create a .nuget folder. You can use Windows Explorer to name it .nuget. for it to successfully save as .nuget (it automatically removes the last period) but directly trying to name it .nuget may not work (you may get an error or it may change the name, depending on your version of Windows). Or name the directory nuget, and open the parent directory in command line prompt. type. ren nuget .nuget
  4. Inside of that folder, create a NuGet.config file and add the following contents and save it:


<?xml version="1.0" encoding="utf-8"?>
        <add key="disableSourceControlIntegration" value="true" />
  1. Go back in your .sln's folder and create a new text file and name it .tfignore (if using Windows Explorer, use the same trick as above and name it .tfignore.)
  2. Put the following content into that file:


# Ignore the NuGet packages folder in the root of the repository.
# If needed, prefix 'packages' with additional folder names if it's 
# not in the same folder as .tfignore.

# include package target files which may be required for msbuild,
# again prefixing the folder name as needed.
  1. Save all of this, commit it to TFS, then close & re-open Visual Studio and the Team Explorer should no longer identify the packages folder as a pending check-in.
  2. Copy/pasted via Windows Explorer the .tfignore file and .nuget folder to all of my various solutions and committed them and I no longer have the packages folder trying to sneak into my source control repo!

Further Customization

While not mine, I have found this .tfignore template by sirkirby to be handy. The example in my answer covers the Nuget packages folder but this template includes some other things as well as provides additional examples that can be useful if you wish to customize this further.

XMLHttpRequest cannot load an URL with jQuery

You can't do a XMLHttpRequest crossdomain, the only "option" would be a technique called JSONP, which comes down to this:

To start request: Add a new <script> tag with the remote url, and then make sure that remote url returns a valid javascript file that calls your callback function. Some services support this (and let you name your callback in a GET parameters).

The other easy way out, would be to create a "proxy" on your local server, which gets the remote request and then just "forwards" it back to your javascript.


I see jQuery has built-in support for JSONP, by checking if the URL contains "callback=?" (where jQuery will replace ? with the actual callback method). But you'd still need to process that on the remote server to generate a valid response.

How to cast int to enum in C++?

Spinning off the closing question, "how do I convert a to type Test::A" rather than being rigid about the requirement to have a cast in there, and answering several years late only because this seems to be a popular question and nobody else has mentioned the alternative, per the C++11 standard:

5.2.9 Static cast

... an expression e can be explicitly converted to a type T using a static_cast of the form static_cast<T>(e) if the declaration T t(e); is well-formed, for some invented temporary variable t (8.5). The effect of such an explicit conversion is the same as performing the declaration and initialization and then using the temporary variable as the result of the conversion.

Therefore directly using the form t(e) will also work, and you might prefer it for neatness:

auto result = Test(a);

What is <scope> under <dependency> in pom.xml for?

Scope tag is always use to limit the transitive dependencies and availability of the jar at class path level.If we don't provide any scope then the default scope will work i.e. Compile .

on change event for file input element

Use the files filelist of the element instead of val()


How to print Unicode character in Python?

Just one more thing that hasn't been added yet

In Python 2, if you want to print a variable that has unicode and use .format(), then do this (make the base string that is being formatted a unicode string with u'':

>>> text = "Université de Montréal"
>>> print(u"This is unicode: {}".format(text))
>>> This is unicode: Université de Montréal

IEnumerable<object> a = new IEnumerable<object>(); Can I do this?

You can for example create an instance of List<object>, which implements IEnumerable<object>. Example:

List<object> list = new List<object>();

IEnumerable<object> en = list;

How is AngularJS different from jQuery

  1. While Angular 1 was a framework, Angular 2 is a platform. (ref)

To developers, Angular2 provides some features beyond showing data on screen. For example, using angular2 cli tool can help you "pre-compile" your code and generate necessary javascript code (tree-shaking) to shrink the download size down to 35Kish.

  1. Angular2 emulated Shadow DOM. (ref)

This opens a door for server rendering that can address SEO issue and work with Nativescript etc that don't work on browsers.

AngularJS is a framework. It has following features

  1. Two way data binding
  2. MVW pattern (MVC-ish)
  3. Template
  4. Custom-directive (reusable components, custom markup)
  5. REST-friendly
  6. Deep Linking (set up a link for any dynamic page)
  7. Form Validation
  8. Server Communication
  9. Localization
  10. Dependency injection
  11. Full testing environment (both unit, e2e)

check this presentation and this great introduction

Don't forget to read the official developer guide

Or learn it from these awesome video tutorials

If you want to watch more tutorial video, check out this post, Collection of best 60+ AngularJS tutorials.

You can use jQuery with AngularJS without any issue.

In fact, AngularJS uses jQuery lite in it, which is a great tool.

From FAQ

Does Angular use the jQuery library?

Yes, Angular can use jQuery if it's present in your app when the application is being bootstrapped. If jQuery is not present in your script path, Angular falls back to its own implementation of the subset of jQuery that we call jQLite.

However, don't try to use jQuery to modify the DOM in AngularJS controllers, do it in your directives.


Angular2 is released. Here is a great list of resource for starters

Reading specific columns from a text file in python

It may help:

import csv
with open('csv_file','r') as f:
    # Printing Specific Part of CSV_file
    # Printing last line of second column
    lines = list(csv.reader(f, delimiter = ' ', skipinitialspace = True))
    # For printing a range of rows except 10 last rows of second column
    for i in range(len(lines)-10):

Cache busting via params

As others have said, cache busting with a query param is usually considered a Bad Idea (tm), and has been for a long time. It's better to reflect the version in the file name. Html5 Boilerplate recommends against using the query string, among others.

That said, of the recommendations I have seen which cited a source, all seem to take their wisdom from a 2008 article by Steve Souders. His conclusions are based on the behaviour of proxies at the time, and they may or may not be relevant these days. Still, in the absence of more current information, changing the file name is the safe option.

Difference between using bean id and name in Spring configuration file

Is there difference in defining Id & name in ApplicationContext xml ? No As of 3.1(spring), id is also defined as an xsd:string type. It means whatever characters allowed in defining name are also allowed in Id. This was not possible prior to Spring 3.1.

Why to use name when it is same as Id ? It is useful for some situations, such as allowing each component in an application to refer to a common dependency by using a bean name that is specific to that component itself.

For example, the configuration metadata for subsystem A may refer to a DataSource via the name subsystemA-dataSource. The configuration metadata for subsystem B may refer to a DataSource via the name subsystemB-dataSource. When composing the main application that uses both these subsystems the main application refers to the DataSource via the name myApp-dataSource. To have all three names refer to the same object you add to the MyApp configuration metadata the following 

<bean id="myApp-dataSource" name="subsystemA-dataSource,subsystemB-dataSource" ..../>

Alternatively, You can have separate xml configuration files for each sub-system and then you can make use of
alias to define your own names.

<alias name="subsystemA-dataSource" alias="subsystemB-dataSource"/>
<alias name="subsystemA-dataSource" alias="myApp-dataSource" />

How can I render HTML from another file in a React component?

You can use dangerouslySetInnerHTML to do this:

import React from 'react';
function iframe() {
    return {
        __html: '<iframe src="./Folder/File.html" width="540" height="450"></iframe>'

export default function Exercises() {
    return (
            <div dangerouslySetInnerHTML={iframe()} />

HTML files must be in the public folder

psql: FATAL: Peer authentication failed for user "dev"

While @flaviodesousa's answer would work, it also makes it mandatory for all users (everyone else) to enter a password.

Sometime it makes sense to keep peer authentication for everyone else, but make an exception for a service user. In that case you would want to add a line to the pg_hba.conf that looks like:

local   all             some_batch_user                         md5

I would recommend that you add this line right below the commented header line:

# TYPE  DATABASE        USER            ADDRESS                 METHOD
local   all             some_batch_user                         md5

You will need to restart PostgreSQL using

sudo service postgresql restart

If you're using 9.3, your pg_hba.conf would most likely be:


Howto: Clean a mysql InnoDB storage engine?

The InnoDB engine does not store deleted data. As you insert and delete rows, unused space is left allocated within the InnoDB storage files. Over time, the overall space will not decrease, but over time the 'deleted and freed' space will be automatically reused by the DB server.

You can further tune and manage the space used by the engine through an manual re-org of the tables. To do this, dump the data in the affected tables using mysqldump, drop the tables, restart the mysql service, and then recreate the tables from the dump files.

"import datetime" v.s. "from datetime import datetime"

try this:

import datetime
from datetime import datetime as dt

today_date =
date_time = dt.strptime(date_time_string, '%Y-%m-%d %H:%M')

strp() doesn't exist. I think you mean strptime.

Can you use @Autowired with static fields?

private static UserService userService = ApplicationContextHolder.getContext().getBean(UserService.class);

Lost connection to MySQL server at 'reading initial communication packet', system error: 0

Someone here suggests that it might be a firewall problem:

I have just had this problem and found it was my firewall. I use PCTools Firewall Plus and it wasn't allowing full access to MySQL. Once I changed that it was fine. Hope that helps.

Could that be it?

Also, someone here suggests that it might be because the MySQL server is bound to the loop-back IP ( / localhost) which effectively cuts you off from connecting from "outside".

If this is the case, you need to upload the script to the webserver (which is probably also running the MySQL server) and keep your server host as 'localhost'

How to simulate a click with JavaScript?

document.getElementById('elementId').dispatchEvent(new MouseEvent("click",{bubbles: true, cancellable: true}));

Follow this link to know about the mouse events using Javascript and browser compatibility for the same

How to configure Visual Studio to use Beyond Compare

I got bored of doing this every 6 months when a new version of Visual Studio comes out, or I move PCs, or a new member joins the team. So, PowerShell:

# .Synopsys
# Sets up Beyond Compare professional as Diff tool for all instances of Visual Studio on this PC
# If you don't use TFS, change the sccProvider as appropriate
    $bcPath = 'C:\Program Files (x86)\Beyond Compare 3\BComp.exe',
    $sccProvider = 'TeamFoundation'

$ErrorActionPreference = 'stop';
$baseKey = 'REGISTRY::\HKCU\Software\Microsoft\VisualStudio\*'

function SetRegKeyProperties($keyPath, [hashtable]$keyProps){
    if(!(Test-Path $keyPath)){
        Write-Verbose "Creating $keyPath"
        # Force required here to recursively create registry path
        [void] (new-item $keyPath -Type:Directory -Force);
    foreach($prop in $keyProps.GetEnumerator()){
        Set-ItemProperty -Path:$keyPath -Name:$prop.Key -Value:$prop.Value;

$configBases = dir $baseKey | ? { $_.PSChildName -match '^\d+\.\d$' }
foreach($item in $configBases){
    Write-Host "Configuring $item"

    $diffToolsKey = Join-Path $item.PSPath "$sccProvider\SourceControl\DiffTools"
    SetRegKeyProperties (Join-path $diffToolsKey '.*\Compare') @{Command=$bcPath;Arguments='%1 %2 /title1=%6 /title2=%7'}
    SetRegKeyProperties (Join-path $diffToolsKey '.*\Merge') @{Command=$bcPath;Arguments='%1 %2 %3 %4 /title1=%6 /title2=%7 /title3=%8 /title4=%9'}

Works on my machine. YMMV. No warranties, no refunds. VS doesn't appear to cache the key, so takes effect immediately.

php codeigniter count rows

public function record_count() {
   return $this->db->count_all("tablename");

Python: "TypeError: __str__ returned non-string" but still prints to output?

Method __str__ should return string, not print.

def __str__(self):
    return 'Memo={0}, Tag={1}'.format(self.memo, self.tags)

Markdown `native` text alignment

For Markdown Extra you can use custom attributes:

# Example text {style=text-align:center}

This works for headers and blockquotes, but not for paragraphs, inline elements and code blocks.

A shorter version (but not supported in HTML 5):

# Example text {align=center}

How to negate 'isblank' function

If you're trying to just count how many of your cells in a range are not blank try this:


Example: (assume that it starts from A1 downwards):




=COUNTA(A1:A6) returns 4 since there are two blank cells in there.

Reverse a string in Java

Having surrogate pairs in input string, you have to leave them not reversed, so good and generic way of reversing the string is using StringBuilder.reverse as it handles extended character set correctly. So called supplementary characters consisting of surrogate pairs are unicode values up to U+10FFFF encoded as two consecutive chars.

Here is my solution:

String aString = "abcdef";
String reversedString = aString
       .collect(Collectors.collectingAndThen(Collectors.toList(), aList -> {
           return String.join("", aList);
  • String.codepoints returns stream of integers surrogate pair (double chars) packed in one integer, this is different that String.chars for which one integer = one char
  • as of Java 11 Character.toString also accepts codepoint, and returns either String of length 1 or 2 if there is surrogate pair

Expression must have class type

Summary: Instead of a.f(); it should be a->f();

In main you have defined a as a pointer to object of A, so you can access functions using the -> operator.

An alternate, but less readable way is (*a).f()

a.f() could have been used to access f(), if a was declared as: A a;

Programmatically Install Certificate into Mozilla

I had a similar issue on a client site where the client required a authority certificate to be installed automatically for 2000+ windows users.

I created the following .vbs script to import the certificate into the current logged on users firefox cert store.

The script needs to be put in the directory containing a working copy of certutil.exe (the nss version) but programatically determines the firefox profiles location.

Option Explicit

On error resume next

Const DEBUGGING              = true
const SCRIPT_VERSION        = 0.1
Const CERTUTIL_EXCUTABLE    = "certutil.exe"
Const ForReading = 1

Dim strCertDirPath, strCertutil, files, slashPosition, dotPosition, strCmd, message
Dim file, filename, filePath, fileExtension

Dim WshShell            : Set WshShell            = WScript.CreateObject("WScript.Shell")
Dim objFilesystem      : Set objFilesystem    = CreateObject("Scripting.FileSystemObject") 
Dim certificates        : Set certificates      = CreateObject("Scripting.Dictionary")
Dim objCertDir
Dim UserFirefoxDBDir
Dim UserFirefoxDir
Dim objINIFile
Dim strNextLine,Tmppath,intLineFinder, NickName

vAPPDATA = WshShell.ExpandEnvironmentStrings("%APPDATA%") 
strCertDirPath    = WshShell.CurrentDirectory
strCertutil      = strCertDirPath & "\" & CERTUTIL_EXCUTABLE
UserFirefoxDir = vAPPDATA & "\Mozilla\Firefox"
NickName = "Websense Proxy Cert"

Set objINIFile = objFilesystem.OpenTextFile( UserFireFoxDir & "\profiles.ini", ForReading)

Do Until objINIFile.AtEndOfStream
    strNextLine = objINIFile.Readline

    intLineFinder = InStr(strNextLine, "Path=")
    If intLineFinder <> 0 Then
        Tmppath = Split(strNextLine,"=")
        UserFirefoxDBDir = UserFirefoxDir & "\" & replace(Tmppath(1),"/","\")

    End If  

'output UserFirefoxDBDir

If objFilesystem.FolderExists(strCertDirPath) And objFilesystem.FileExists(strCertutil) Then
    Set objCertDir = objFilesystem.GetFolder(strCertDirPath)
    Set files = objCertDir.Files

    For each file in files
        slashPosition = InStrRev(file, "\")
        dotPosition  = InStrRev(file, ".")
        fileExtension = Mid(file, dotPosition + 1)
        filename      = Mid(file, slashPosition + 1, dotPosition - slashPosition - 1)

        If LCase(fileExtension) = "cer" Then        
            strCmd = chr(34) & strCertutil & chr(34) &" -A -a -n " & chr(34) & NickName & chr(34) & " -i " & chr(34) & file & chr(34) & " -t " & chr(34) & "TCu,TCu,TCu" & chr(34) & " -d " & chr(34) & UserFirefoxDBDir & chr(34)
        End If        
    WshShell.LogEvent EVENTLOG_WARNING, "Script: " & WScript.ScriptFullName & " - version:" & SCRIPT_VERSION & vbCrLf & vbCrLf & message
End If

function output(message)
        Wscript.echo message
    End if
End function

Set WshShell  = Nothing
Set objFilesystem = Nothing

Generate Row Serial Numbers in SQL Query

Implementing Serial Numbers Without Ordering Any of the Columns

enter image description here

Demo SQL Script-

IF OBJECT_ID('Tempdb..#TestTable') IS NOT NULL
    DROP TABLE #TestTable;

CREATE TABLE #TestTable (Names VARCHAR(75), Random_No INT); 

INSERT INTO #TestTable (Names,Random_No) VALUES
 ('Animal', 363)
,('Bat', 847)
,('Cat', 655)
,('Duet', 356)
,('Eagle', 136)
,('Frog', 784)
,('Ginger', 690); 

SELECT * FROM #TestTable;

There are ‘N’ methods for implementing Serial Numbers in SQL Server. Hereby, We have mentioned the Simple Row_Number Function to generate Serial Numbers.

ROW_NUMBER() Function is one of the Window Functions that numbers all rows sequentially (for example 1, 2, 3, …) It is a temporary value that will be calculated when the query is run. It must have an OVER Clause with ORDER BY. So, we cannot able to omit Order By Clause Simply. But we can use like below-

SQL Script

IF OBJECT_ID('Tempdb..#TestTable') IS NOT NULL
    DROP TABLE #TestTable;

CREATE TABLE #TestTable (Names VARCHAR(75), Random_No INT); 

INSERT INTO #TestTable (Names,Random_No) VALUES
 ('Animal', 363)
,('Bat', 847)
,('Cat', 655)
,('Duet', 356)
,('Eagle', 136)
,('Frog', 784)
,('Ginger', 690); 


In the Above Query, We can Also Use SELECT 1, SELECT ‘ABC’, SELECT ” Instead of SELECT NULL. The result would be Same.

Convert DateTime to a specified Format

Easy peasy:

var date = DateTime.Parse("14/11/2011"); // may need some Culture help here

Take a look at DateTime.ToString() method, Custom Date and Time Format Strings and Standard Date and Time Format Strings

string customFormattedDateTimeString = DateTime.Now.ToString("yyyy-MM-dd");

"Cannot update paths and switch to branch at the same time"

You could follow these steps when you stumble upon this issue:

  1. Run the following command to list the branches known for your local repository.

git remote show origin

which outputs this:

 remote origin
  Fetch URL: <your_git_path>
  Push  URL: <your_git_path>
  HEAD branch: development
  Remote branches:
    development                             tracked
    Feature2                                tracked
    master                                  tracked
    refs/remotes/origin/Feature1         stale (use 'git remote prune' to remove)
  Local branches configured for 'git pull':
    Feature2     merges with remote Feature2
    development  merges with remote development
    master       merges with remote master
  Local refs configured for 'git push':
    Feature2     pushes to Feature2     (up to date)
    development  pushes to development (up to date)
    master       pushes to master      (local out of date)
  1. After verifying the details like (fetch URL, etc), run this command to fetch any new branch(i.e. which you may want to checkout in your local repo) that exist in the remote but not in your local.
» git remote update

Fetching origin
From gitlab.domain.local:ProjectGroupName/ProjectName
 * [new branch]      Feature3    -> Feature3

As you can see the new branch has been fetched from remote.
3. Finally, checkout the branch with this command

» git checkout -b Feature3 origin/Feature3

Branch Feature3 set up to track remote branch Feature3 from origin.
Switched to a new branch 'Feature3'

It is not necessary to explicitly tell Git to track(using --track) the branch with remote.

The above command will set the local branch to track the remote branch from origin.

How to convert a DataTable to a string in C#?

very vague ....

id bung it into a dataset simply so that i can output it easily as xml ....

failing that why not iterate through its row and column collections and output them?

How to sign an android apk file

I ran into this problem and was solved by checking the min sdk version in the manifest. It was set to 15 (ICS), but my phone was running 10(Gingerbread)

List<Object> and List<?>

List is an interface so you can't instanciate it. Use any of its implementatons instead e.g.

List<Object> object = new List<Object>();

About List : you can use any object as a generic param for it instance:

List<?> list = new ArrayList<String>();


List<?> list = new ArrayList<Integer>();

While using List<Object> this declaration is invalid because it will be type missmatch.

Freeze screen in chrome debugger / DevTools panel for popover inspection?

To be able to inspect any element do the following. This should work even if it's hard to duplicate the hover state:

  • Run the following javascript in the console. This will break into the debugger in 5 seconds.

    setTimeout(function(){debugger;}, 5000)

  • Go show your element (by hovering or however) and wait until Chrome breaks into the Debugger.

  • Now click on the Elements tab in the Chrome Inspector, and you can look for your element there.
  • You may also be able to click on the Find Element icon (looks like a magnifying glass) and Chrome will let you go and inspect and find your element on the page by right clicking on it, then choosing Inspect Element

Note that this approach is a slight variation to this other great answer on this page.

SQL Delete Records within a specific Range

you can also just change your delete to a select *

and test your selection

the records selected will be the same as the ones deleted

you can also wrap your statement in a begin / rollback if you are not sure - test the statement then if all is good remove rollback

for example


will show all the records matching the where if they are the wants you 'really' want to delete then use


You can also create a trigger / which catches deletes and puts them into a history table

so if you delete something by mistake you can always get it back

(keep your history table records no older than say 6 months or whatever business rules say)

How to Display Multiple Google Maps per page with API V3

Here is how I have been able to generate multiple maps on the same page using Google Map API V3. Kindly note that this is an off the cuff code that addresses the issue above.

The HTML bit

<div id="map_canvas" style="width:700px; height:500px; margin-left:80px;"></div>
<div id="map_canvas2" style="width:700px; height:500px; margin-left:80px;"></div>

Javascript for map initialization

<script type="text/javascript">
var map, map2;

function initialize(condition) {
    // create the maps
    var myOptions = {
        zoom: 14,
        center: new google.maps.LatLng(0.0, 0.0),
        mapTypeId: google.maps.MapTypeId.ROADMAP
    map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);

    map2 = new google.maps.Map(document.getElementById("map_canvas2"), myOptions);

How do I create executable Java program?

If you are using NetBeans, you just press f11 and your project will be build. The default path is projectfolder\dist

How to set javascript variables using MVC4 with Razor

This is how I solved the problem:

@{int proID = 123; int nonProID = 456;}

<script type="text/javascript">
var nonID = Number(@nonProID);
var proID = Number(@proID);

It is self-documenting and it doesn't involve conversion to and from text.

Note: be careful to use the Number() function not create new Number() objects - as the exactly equals operator may behave in a non-obvious way:

var y = new Number(123); // Note incorrect usage of "new"
var x = new Number(123);
alert(y === 123); // displays false
alert(x == y); // displays false

How to extract the decision rules from scikit-learn decision-tree?

Just use the function from sklearn.tree like this

from sklearn.tree import export_graphviz
                out_file = "",
                feature_names = tree.columns) //or just ["petal length", "petal width"]

And then look in your project folder for the file, copy the ALL the content and paste it here and generate your graph :)

Round a floating-point number down to the nearest integer?

If you working with numpy, you can use the following solution which also works with negative numbers (it's also working on arrays)

import numpy as np
def round_down(num):
    if num < 0:
        return -np.ceil(abs(num))
        return np.int32(num)
round_down = np.vectorize(round_down)

round_down([-1.1, -1.5, -1.6, 0, 1.1, 1.5, 1.6])
> array([-2., -2., -2.,  0.,  1.,  1.,  1.])

I think it will also work if you just use the math module instead of numpy module.

Capturing browser logs with Selenium WebDriver using Java

In a more concise way, you can do:

LogEntries logs = driver.manage().logs().get(LogType.BROWSER);

For me it worked wonderfully for catching JS errors in console. Then you can add some verification for its size. For example, if it is > 0, add some error output.

Button button = findViewById( always resolves to null in Android Studio is not part of R.layout.activity_main. How should the activity find it in the content view?

The layout that contains the button is displayed by the Fragment, so you have to get the Button there, in the Fragment.

How to delete all the rows in a table using Eloquent?

Can do a loop too..

$collection = Model::get();

foreach($collection as $c) {



Why should I use an IDE?

I have used Emacs as my primary environment for both development and mail/news for about 10 year (1994-2004). I discovered the power of IDEs when I forced myself to learn Java in 2004, and to my surprise that I actually liked the IDE (IntelliJ IDEA).

I will not go into specific reasons since a lot of them have already been mentioned here -- just remember that the different people love different features. Me and a colleague used the same IDE, both of us used just a fraction of the features available, and we disliked each others way of using the IDE (but we both liked the IDE itself).

But there is one advantage with IDEs over Emacs/Vim related environments I want to focus on: You spend less time installing/configuring the features you want.

With Wing IDE (for Python) I'm ready to start developing 15-20 minutes after installation. No idea how many hours I would need to get the features I use up and running with Emacs/Vim. :)

Converting a float to a string without rounding it

Other answers already pointed out that the representation of floating numbers is a thorny issue, to say the least.

Since you don't give enough context in your question, I cannot know if the decimal module can be useful for your needs:

Among other things you can explicitly specify the precision that you wish to obtain (from the docs):

>>> getcontext().prec = 6
>>> Decimal('3.0')
>>> Decimal('3.1415926535')
>>> Decimal('3.1415926535') + Decimal('2.7182818285')
>>> getcontext().rounding = ROUND_UP
>>> Decimal('3.1415926535') + Decimal('2.7182818285')

A simple example from my prompt (python 2.6):

>>> import decimal
>>> a = decimal.Decimal('10.000000001')
>>> a
>>> print a
>>> b = decimal.Decimal('10.00000000000000000000000000900000002')
>>> print b
>>> print str(b)
>>> len(str(b/decimal.Decimal('3.0')))

Maybe this can help? decimal is in python stdlib since 2.4, with additions in python 2.6.

Hope this helps, Francesco

How to check all checkboxes using jQuery?


    <script type="text/javascript" src=""></script>
    <TITLE>Multiple Checkbox Select/Deselect - DEMO</TITLE>
    <H2>Multiple Checkbox Select/Deselect - DEMO</H2>
<table border="1">
    <th><input type="checkbox" id="selectall"/></th>
    <th>Cell phone</th>
    <td align="center"><input type="checkbox" class="case" name="case" value="1"/></td>
    <td>BlackBerry Bold 9650</td>
    <td align="center"><input type="checkbox" class="case" name="case" value="2"/></td>
    <td>Samsung Galaxy</td>
    <td align="center"><input type="checkbox" class="case" name="case" value="3"/></td>
    <td>Droid X</td>
    <td align="center"><input type="checkbox" class="case" name="case" value="4"/></td>
    <td>HTC Desire</td>
    <td align="center"><input type="checkbox" class="case" name="case" value="5"/></td>
    <td>Apple iPhone 4</td>


jQuery Code

<SCRIPT language="javascript">

    // add multiple select / deselect functionality
    $("#selectall").click(function () {
          $('.case').attr('checked', this.checked);

    // if all checkbox are selected, check the selectall checkbox
    // and viceversa

        if($(".case").length == $(".case:checked").length) {
            $("#selectall").attr("checked", "checked");
        } else {


View Demo

Click here to View Demo

Want to download a Git repository, what do I need (windows machine)?

I don't want to start a "What's the best unix command line under Windows" war, but have you thought of Cygwin? Git is in the Cygwin package repository.

And you get a lot of beneficial side-effects! (:-)

Can a variable number of arguments be passed to a function?

Adding to unwinds post:

You can send multiple key-value args too.

def myfunc(**kwargs):
    # kwargs is a dictionary.
    for k,v in kwargs.iteritems():
         print "%s = %s" % (k, v)

myfunc(abc=123, efh=456)
# abc = 123
# efh = 456

And you can mix the two:

def myfunc2(*args, **kwargs):
   for a in args:
       print a
   for k,v in kwargs.iteritems():
       print "%s = %s" % (k, v)

myfunc2(1, 2, 3, banan=123)
# 1
# 2
# 3
# banan = 123

They must be both declared and called in that order, that is the function signature needs to be *args, **kwargs, and called in that order.

ToList().ForEach in Linq

you want this?

    employees.ForEach(emp =>
        collection.AddRange(emp.Departments.Where(dept => { dept.SomeProperty = null; return true; }));

customize Android Facebook Login button

In newer Facebook SDK, the login and logout text name is :


Visualizing decision tree in scikit-learn

Here is the minimal code to have a nice looking graph with just 3 lines of code :

from sklearn import tree
import pydotplus


I have added the plt.imgshow to view the graph it Jupyter Notebook. You can ignore it if you are only interested in saving the png file.

I installed the following dependencies:

pip3 install graphviz
pip3 install pydotplus

For MacOs the pip version of Graphviz did not work. Following Graphviz's official documentation I installed it with brew and everything worked fine.

brew install graphviz

enter image description here

Android - SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length

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

removing bold styling from part of a header

If you don't want a separate CSS file, you can use inline CSS:

<h1>This text should be bold, <span style="font-weight:normal">but this text should not</span></h1>

However, as Madara's comment suggests, you might want to consider putting the unbolded part in a different header, depending on the use case involved.

How to create an empty array in PHP with predefined size?

 $array = new SplFixedArray(5);
   echo $array->getSize()."\n";

You can use PHP documentation more info check this link

Regex: ignore case sensitivity

[gG][aAbB].* probably simples solution if the pattern is not too complicated or long.

Generate unique random numbers between 1 and 100

Here is my ES6 version I cobbled together. I'm sure it can be a little more consolidated.

function randomArray(i, min, max) {_x000D_
  min = Math.ceil(min);_x000D_
  max = Math.floor(max);_x000D_
  let arr = Array.from({length: i}, () => Math.floor(Math.random()* (max - min)) + min);_x000D_
  return arr.sort();_x000D_
 let uniqueItems = [ Set(randomArray(8, 0, 100))]_x000D_

Why is semicolon allowed in this python snippet?

It's allowed because authors decided to allow it:

If move to question why authors decided todo so, I guess it's so because semi-column is allowed as simple statement termination at least in the following langages: C++, C, C#, R, Matlab,Perl,...

So it's faster to move into usage of Python for people with background in other language. And there are no lose of generality in such deicison.

check null,empty or undefined angularjs

You can use angular's function called angular.isUndefined(value) returns boolean.

You may read more about angular's functions here: AngularJS Functions (isUndefined)

Keeping session alive with Curl and PHP

You also need to set the option CURLOPT_COOKIEFILE.

The manual describes this as

The name of the file containing the cookie data. The cookie file can be in Netscape format, or just plain HTTP-style headers dumped into a file. If the name is an empty string, no cookies are loaded, but cookie handling is still enabled.

Since you are using the cookie jar you end up saving the cookies when the requests finish, but since the CURLOPT_COOKIEFILE is not given, cURL isn't sending any of the saved cookies on subsequent requests.

Landscape printing from HTML

This also worked for me:

@media print and (orientation:landscape) { … }

HTML5 video (mp4 and ogv) problems in Safari and Firefox - but Chrome is all good

Just need to change one letter:), rename 640x360.ogv to 640x360.ogg, it will work for all the 3 browers.

Can a for loop increment/decrement by more than one?

A for loop:


Means the following:

while (true) {
    if (!TEST)

You can write almost any expression for INIT, TEST, ADVANCE, and BODY.

Do note that the ++ operators and variants are operators with side-effects (one should try to avoid them if you are not using them like i+=1 and the like):

  • ++i means i+=1; return i
  • i++ means oldI=i; i+=1; return oldI


> i=0
> [i++, i, ++i, i, i--, i, --i, i]
[0, 1, 2, 2, 2, 1, 0, 0]

trying to animate a constraint in swift

It's very important to point out that view.layoutIfNeeded() applies to the view subviews only.

Therefore to animate the view constraint, it is important to call it on the view-to-animate superview as follows:

    topConstraint.constant = heightShift

    UIView.animate(withDuration: 0.3) {

        // request layout on the *superview*

An example for a simple layout as follows:

class MyClass {

    /// Container view
    let container = UIView()
        /// View attached to container
        let view = UIView()

    /// Top constraint to animate
    var topConstraint = NSLayoutConstraint()

    /// Create the UI hierarchy and constraints
    func createUI() {

        // Create the top constraint
        topConstraint = view.topAnchor.constraint(equalTo: container.topAnchor, constant: 0)

        view.translatesAutoresizingMaskIntoConstraints = false

        // Activate constaint(s)

    /// Update view constraint with animation
    func updateConstraint(heightShift: CGFloat) {
        topConstraint.constant = heightShift

        UIView.animate(withDuration: 0.3) {

            // request layout on the *superview*

Error in launching AVD with AMD processor

While creating a Virtual Device select the ARM system Image. Others have suggested to install HAXM, but the truth is haxm wont work on amd platform or even if it does as android studio does not supports amd-vt on windows the end result will still be a very very slow emulator to run and operate. My recommendation would be to either use alternative emulator like Genymotion (works like a charm with Gapps installed) or switch to linux as then you will get the benefit of amd-vt and emulator will run a lot faster.

Unable to show a Git tree in terminal


If you want a interactive tree, you can use tig. It can be installed by brew on OSX and apt-get in Linux.

brew install tig

This is what you get:

enter image description here

Split code over multiple lines in an R script

For that particular case there is file.path :

File <- file.path("~", 

DataAnnotations validation (Regular Expression) in mvc 4 - razor view

We've had similar issue in the past (as mentioned by TweeZz). In our case we're controlling outputting of TextBoxFor by our custom htmlHelper extension method which is building MvcHtmlString, there in one step we need to add these unobtrusive validation attributes, which is done via

var attrs = htmlHelper.GetUnobtrusiveValidationAttributes(name, metadata)

after call to this method, attributes are html encoded, so we simply check if there was Regular expression validator there and if so, we html unencode this attribute and then merge them into tagBuilder (for building "input" tag)

    attrs["data-val-regex"] = ((string)attrs["data-val-regex"]).Replace("&amp;","&");

We only cared about & amps, that's why this literal replacement

What is the difference between and re.match?

re.match attempts to match a pattern at the beginning of the string. attempts to match the pattern throughout the string until it finds a match.

Correct way to import lodash

Import specific methods inside of curly brackets

import { map, tail, times, uniq } from 'lodash';


  • Only one import line(for a decent amount of functions)
  • More readable usage: map() instead of later in the javascript code.


  • Every time we want to use a new function or stop using another - it needs to be maintained and managed

Copied from:The Correct Way to Import Lodash Libraries - A Benchmark article written by Alexander Chertkov.

How can a LEFT OUTER JOIN return more records than exist in the left table?

It isn't impossible. The number of records in the left table is the minimum number of records it will return. If the right table has two records that match to one record in the left table, it will return two records.

HttpWebRequest-The remote server returned an error: (400) Bad Request

Are you sure you should be using POST not PUT?

POST is usually used with application/x-www-urlencoded formats. If you are using a REST API, you should maybe be using PUT? If you are uploading a file you probably need to use multipart/form-data. Not always, but usually, that is the right thing to do..

Also you don't seem to be using the credentials to log in - you need to use the Credentials property of the HttpWebRequest object to send the username and password.

Update statement with inner join on Oracle

Do not use some of the answers above.

Some suggest the use of nested SELECT, don't do that, it is excruciatingly slow. If you have lots of records to update, use join, so something like:

update (select bonus 
        from employee_bonus b 
        inner join employees e on b.employee_id = e.employee_id 
        where e.bonus_eligible = 'N') t
set t.bonus = 0;

See this link for more details.

Also, ensure that there are primary keys on all the tables you are joining.

How to emulate a do-while loop in Python?

Why don't you just do

for s in l :
    print s
print "done"


What is the difference between public, protected, package-private and private in Java?

David's answer provides the meaning of each access modifier. As for when to use each, I'd suggest making public all classes and the methods of each class that are meant for external use (its API), and everything else private.

Over time you'll develop a sense for when to make some classes package-private and when to declare certain methods protected for use in subclasses.

Responsive Google Map?

Here a standard CSS solution + JS for the map's height resizing


#map_canvas {
   width: 100%;


// On Resize
    $('#map_canvas').height($( window ).height());

JsFiddle demo :

Meaning of = delete after function declaration

  1. = 0 means that a function is pure virtual and you cannot instantiate an object from this class. You need to derive from it and implement this method
  2. = delete means that the compiler will not generate those constructors for you. AFAIK this is only allowed on copy constructor and assignment operator. But I am not too good at the upcoming standard.

How to send email to multiple address using System.Net.Mail

I'm used "for" operator.

    string s = textBox2.Text;
    string[] f = s.Split(',');

    for (int i = 0; i < f.Length; i++)
        MailMessage message = new MailMessage(); // Create instance of message
        message.To.Add(f[i]); // Add receiver
        message.From = new System.Net.Mail.MailAddress(c);// Set sender .In this case the same as the username
        message.Subject = label3.Text; // Set subject
        message.Body = richTextBox1.Text; // Set body of message
        client.Send(message); // Send the message
        message = null; // Clean up


catch (Exception ex)


Android Studio and cannot resolve symbol

I found that if you have comments in your build.gradle it may break when you try to add a new support library. So make sure you check your build.gradle and see if it looks alright manually.

How to set NODE_ENV to production/development in OS X

Before running your app, you can do this in console,

export NODE_ENV=production

Or if you are in windows you could try this:

SET NODE_ENV=production

for PowerShell:


or you can run your app like this:

NODE_ENV=production node app.js

You can also set it in your js file:

process.env.NODE_ENV = 'production';

But I don't suggest to do it in your runtime file, since it's not easy to open up VIM in your server and change it to production. You can make a config.json file in your directory and everytime your app runs, it reads from it and sets the configuration.

@AspectJ pointcut for all methods of a class with specific annotation

From Spring's AnnotationTransactionAspect:

 * Matches the execution of any public method in a type with the Transactional
 * annotation, or any subtype of a type with the Transactional annotation.
private pointcut executionOfAnyPublicMethodInAtTransactionalType() :
    execution(public * ((@Transactional *)+).*(..)) && within(@Transactional *);

Finding the length of a Character Array in C

Provided the char array is null terminated,

char chararray[10] = { 0 };
size_t len = strlen(chararray);

How to use vagrant in a proxy environment?

Installing proxyconf will solve this, but behind a proxy you can't install a plugin simply using the command vagrant plugin install, Bundler will raise an error.

set your proxy in your environment if you're using a unix like system

export http_proxy=http://user:password@host:port

or get a more detailed answer here: How to use bundler behind a proxy?

after this set up proxyconf

How to use fetch in typescript

Actually, pretty much anywhere in typescript, passing a value to a function with a specified type will work as desired as long as the type being passed is compatible.

That being said, the following works...

      .then(res => res.json())
      .then((res: Actor) => {
          // res is now an Actor

I wanted to wrap all of my http calls in a reusable class - which means I needed some way for the client to process the response in its desired form. To support this, I accept a callback lambda as a parameter to my wrapper method. The lambda declaration accepts an any type as shown here...

callBack: (response: any) => void

But in use the caller can pass a lambda that specifies the desired return type. I modified my code from above like this...

  .then(res => res.json())
  .then(res => {
      if (callback) {
        callback(res);    // Client receives the response as desired type.  

So that a client can call it with a callback like...

(response: IApigeeResponse) => {
    // Process response as an IApigeeResponse

Cloudfront custom-origin distribution returns 502 "ERROR The request could not be satisfied." for some URLs

In my case, it was because we had an invalid ssl cert. The problem was on our staging box and we use our prod cert on that as well. It had worked for the past couple of years with this configuration, but all of a sudden we started getting this error. Strange.

If others are getting this error, check that the ssl certificate is valid. You can enable logging to s3 via the AWS CloudFront Distribution interface to aid debugging.

Also, you can refer to amazon's docs on the matter here:

RecyclerView and java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder in Samsung devices

Problem occured for me only when:

I created the Adapter with an empty list. Then I inserted items and called notifyItemRangeInserted.


I solved this by creating the Adapter only after I have the first chunk of data and initialzing it with it right away. The next chunk could then be inserted and notifyItemRangeInserted called with no problem .

Maximum filename length in NTFS (Windows XP and Windows Vista)?

Individual components of a filename (i.e. each subdirectory along the path, and the final filename) are limited to 255 characters, and the total path length is limited to approximately 32,000 characters.

However, on Windows, you can't exceed MAX_PATH value (259 characters for files, 248 for folders). See for full details.

React navigation goBack() and update parent state

You can pass a callback function as parameter when you call navigate like this:

  const DEMO_TOKEN = await AsyncStorage.getItem('id_token');
  if (DEMO_TOKEN === null) {
    this.props.navigation.navigate('Login', {
      onGoBack: () => this.refresh(),
    return -3;
  } else {

And define your callback function:

refresh() {

Then in the login/registration view, before goBack, you can do this:

await AsyncStorage.setItem('id_token', myId);

Update for React Navigation v5:

await AsyncStorage.setItem('id_token', myId);

Format JavaScript date as yyyy-mm-dd

This worked for me to get the current date in the desired format (YYYYMMDD HH:MM:SS):

var d = new Date();

var date1 = d.getFullYear() + '' +
            ((d.getMonth()+1) < 10 ? "0" + (d.getMonth() + 1) : (d.getMonth() + 1)) +
            '' +
            (d.getDate() < 10 ? "0" + d.getDate() : d.getDate());

var time1 = (d.getHours() < 10 ? "0" + d.getHours() : d.getHours()) +
            ':' +
            (d.getMinutes() < 10 ? "0" + d.getMinutes() : d.getMinutes()) +
            ':' +
            (d.getSeconds() < 10 ? "0" + d.getSeconds() : d.getSeconds());

print(date1+' '+time1);

Python's time.clock() vs. time.time() accuracy?

The short answer is: most of the time time.clock() will be better. However, if you're timing some hardware (for example some algorithm you put in the GPU), then time.clock() will get rid of this time and time.time() is the only solution left.

Note: whatever the method used, the timing will depend on factors you cannot control (when will the process switch, how often, ...), this is worse with time.time() but exists also with time.clock(), so you should never run one timing test only, but always run a series of test and look at mean/variance of the times.

Laravel - Eloquent "Has", "With", "WhereHas" - What do they mean?

Document has already explain the usage. So I am using SQL to explain these methods


Assuming there is an Order (orders) has many OrderItem (order_items).

And you have already build the relationship between them.

// App\Models\Order:
public function orderItems() {
    return $this->hasMany('App\Models\OrderItem', 'order_id', 'id');

These three methods are all based on a relationship.


Result: with() return the model object and its related results.

Advantage: It is eager-loading which can prevent the N+1 problem.

When you are using the following Eloquent Builder:


Laravel change this code to only two SQL:

// get all orders:
SELECT * FROM orders; 

// get the order_items based on the orders' id above
SELECT * FROM order_items WHERE order_items.order_id IN (1,2,3,4...);

And then laravel merge the results of the second SQL as different from the results of the first SQL by foreign key. At last return the collection results.

So if you selected columns without the foreign_key in closure, the relationship result will be empty:

Order::with(['orderItems' => function($query) { 
           // $query->sum('quantity');
           $query->select('quantity'); // without `order_id`

#=> result:
[{  id: 1,
    code: '00001',
    orderItems: [],    // <== is empty
    id: 2,
    code: '00002',
    orderItems: [],    // <== is empty


Has will return the model's object that its relationship is not empty.


Laravel change this code to one SQL:

select * from `orders` where exists (
    select * from `order_items` where `order`.`id` = `order_item`.`order_id`


whereHas and orWhereHas methods to put where conditions on your has queries. These methods allow you to add customized constraints to a relationship constraint.

Order::whereHas('orderItems', function($query) {
   $query->where('status', 1);

Laravel change this code to one SQL:

select * from `orders` where exists (
    select * 
    from `order_items` 
    where `orders`.`id` = `order_items`.`order_id` and `status` = 1

What does mvn install in maven exactly do

As you might be aware of, Maven is a build automation tool provided by Apache which does more than dependency management. We can make it as a peer of Ant and Makefile which downloads all of the dependencies required.

On a mvn install, it frames a dependency tree based on the project configuration pom.xml on all the sub projects under the super pom.xml (the root POM) and downloads/compiles all the needed components in a directory called .m2 under the user's folder. These dependencies will have to be resolved for the project to be built without any errors, and mvn install is one utility that could download most of the dependencies.

Further, there are other utils within Maven like dependency:resolve which can be used separately in any specific cases. The build life cycle of the mvn is as below: LifeCycle Bindings

  1. process-resources
  2. compile
  3. process-test-resources
  4. test-compile
  5. test
  6. package
  7. install
  8. deploy

The test phase of this mvn can be ignored by using a flag -DskipTests=true.

When do Java generics require <? extends T> instead of <T> and is there any downside of switching?

First - I have to direct you to -- she does an amazing job.

The basic idea is that you use

<T extends SomeClass>

when the actual parameter can be SomeClass or any subtype of it.

In your example,

Map<String, Class<? extends Serializable>> expected = null;
Map<String, Class<java.util.Date>> result = null;
assertThat(result, is(expected));

You're saying that expected can contain Class objects that represent any class that implements Serializable. Your result map says it can only hold Date class objects.

When you pass in result, you're setting T to exactly Map of String to Date class objects, which doesn't match Map of String to anything that's Serializable.

One thing to check -- are you sure you want Class<Date> and not Date? A map of String to Class<Date> doesn't sound terribly useful in general (all it can hold is Date.class as values rather than instances of Date)

As for genericizing assertThat, the idea is that the method can ensure that a Matcher that fits the result type is passed in.

Change name of folder when cloning from GitHub?

git clone <Repo> <DestinationDirectory>

Clone the repository located at Repo into the folder called DestinationDirectory on the local machine.

Use NSInteger as array index

According to the error message, you declared myLoc as a pointer to an NSInteger (NSInteger *myLoc) rather than an actual NSInteger (NSInteger myLoc). It needs to be the latter.

Convert Pandas DataFrame to JSON format

I think what the OP is looking for is:

with open('temp.json', 'w') as f:
    f.write(df.to_json(orient='records', lines=True))

This should do the trick.

Clearing the terminal screen?

If you change baudrate for example back and forth it clears the Serial Monitor window in version 1.5.3 of Arduino IDE for Intel Galileo development

How to check if command line tools is installed

I think the simplest way which worked for me to find Command line tools is installed or not and its version irrespective of what macOS version is

$brew config

macOS: 10.14.2-x86_64
Xcode: 10.1

This when you have Command Line tools properly installed and paths set properly.

Earlier i got output as below
macOS: 10.14.2-x86_64
Xcode: 10.1

CLT was shown as N/A in spite of having gcc and make working fine and below outputs

$xcode-select -p              
No receipt for '' found at '/'.
$brew doctor
Your system is ready to brew.

Finally doing xcode-select --install resolved my issue of brew unable to find CLT for installing packages as below.

Installing sphinx-doc dependency: python
Warning: Building python from source:
  The bottle needs the Apple Command Line Tools to be installed.
  You can install them, if desired, with:
    xcode-select --install

How to parse JSON and access results


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

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

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

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


Querying a linked sql server

The accepted answer works for me.

Also, in MSSQLMS, you can browse the tree in the Object Explorer to the table you want to query.

[Server] -> Server Objects -> Linked Servers -> [Linked server] -> Catalogs -> [Database] -> [table]

then Right click, Script Table as, SELECT To, New Query Window

And the query will be generated for you with the right FROM, which you can use in your JOIN

DateTime fields from SQL Server display incorrectly in Excel

Here's a simple macro that can be run after pasting data from SSMS. It's easiest if you copy it to your PERSONAL.XLSB file and add a button to the Quick Access Toolbar or a new custom group/tab in the ribbon. Run the macro immediately after pasting while the data is still selected. It can also be run if a single cell is selected within the data - it will automatically select the current area before running (same as ctrl-a). To run the macro on only a subset of data, select the desired subset before running. It can handle the data including or excluding headers, but assumes there at at least 2 rows in the current area.

It efficiently tests each column to see if the first non-NULL value looks to be a date/time value in the strange format. If it is, it sets the entire column to the default system date/time format, even if your date format is 'd/m/y'.

Sub FixSSMSDateFormats()

'Intended for copied data from SSMS and handles headers included
'For selection or current area, checks each column...
'   If the first non-NULL value is in strange time format, then change entire column to system date/time format

Dim values As Variant, r As Long, c As Long

If Selection.Count = 1 Then Selection.CurrentRegion.Select

values = Selection.Value

For c = 1 To UBound(values, 2)

    For r = 2 To UBound(values, 1)
        If TypeName(values(r, c)) = "Double" Then
            If values(r, c) > 1 And Selection(r, c).NumberFormat = "mm:ss.0" Then
                Selection.Columns(c).NumberFormat = "m/d/yyyy h:mm"
            End If
            Exit For
        ElseIf values(r, c) <> "NULL" Then
            Exit For
        End If


End Sub

How to display .svg image using swift

Here's a simple class that can display SVG images in a UIView

import UIKit

public class SVGImageView: UIView {
    private let webView = UIWebView()

    public init() {
        super.init(frame: .zero)
        webView.delegate = self
        webView.scrollView.isScrollEnabled = false
        webView.contentMode = .scaleAspectFit
        webView.backgroundColor = .clear
        webView.snp.makeConstraints { make in

    required public init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")

    deinit {

    public func load(url: String) {
        if let url = URL(string: fullUrl) {
            webView.loadRequest(URLRequest(url: url))

extension SVGImageView: UIWebViewDelegate {
    public func webViewDidFinishLoad(_ webView: UIWebView) {
        let scaleFactor = webView.bounds.size.width / webView.scrollView.contentSize.width
        if scaleFactor <= 0 {

        webView.scrollView.minimumZoomScale = scaleFactor
        webView.scrollView.maximumZoomScale = scaleFactor
        webView.scrollView.zoomScale = scaleFactor

How to remove numbers from a string?

Just want to add since it might be of interest to someone, that you may think about the problem the other way as well. I am not sure if that is of interest here, but I find it relevant.

What I mean by the other way is to say "strip anything that aren't what I am looking for, i.e. if you only want the 'ding' you could say:

var strippedText = ("1 ding ?").replace(/[^a-zA-Z]/g, '');

Which basically mean "remove anything which is nog a,b,c,d....Z (any letter).

Swift alert view with OK and Cancel: which button tapped?

You may want to consider using SCLAlertView, alternative for UIAlertView or UIAlertController.

UIAlertController only works on iOS 8.x or above, SCLAlertView is a good option to support older version.

github to see the details


let alertView = SCLAlertView()
alertView.addButton("First Button", target:self, selector:Selector("firstButton"))
alertView.addButton("Second Button") {
    print("Second button tapped")
alertView.showSuccess("Button View", subTitle: "This alert view has buttons")

PHP - regex to allow letters and numbers only

  • Missing end anchor $
  • Missing multiplier
  • Missing end delimiter

So it should fail anyway, but if it may work, it matches against just one digit at the beginning of the string.


HttpClient.GetAsync(...) never returns when using await/async

You are misusing the API.

Here's the situation: in ASP.NET, only one thread can handle a request at a time. You can do some parallel processing if necessary (borrowing additional threads from the thread pool), but only one thread would have the request context (the additional threads do not have the request context).

This is managed by the ASP.NET SynchronizationContext.

By default, when you await a Task, the method resumes on a captured SynchronizationContext (or a captured TaskScheduler, if there is no SynchronizationContext). Normally, this is just what you want: an asynchronous controller action will await something, and when it resumes, it resumes with the request context.

So, here's why test5 fails:

  • Test5Controller.Get executes AsyncAwait_GetSomeDataAsync (within the ASP.NET request context).
  • AsyncAwait_GetSomeDataAsync executes HttpClient.GetAsync (within the ASP.NET request context).
  • The HTTP request is sent out, and HttpClient.GetAsync returns an uncompleted Task.
  • AsyncAwait_GetSomeDataAsync awaits the Task; since it is not complete, AsyncAwait_GetSomeDataAsync returns an uncompleted Task.
  • Test5Controller.Get blocks the current thread until that Task completes.
  • The HTTP response comes in, and the Task returned by HttpClient.GetAsync is completed.
  • AsyncAwait_GetSomeDataAsync attempts to resume within the ASP.NET request context. However, there is already a thread in that context: the thread blocked in Test5Controller.Get.
  • Deadlock.

Here's why the other ones work:

  • (test1, test2, and test3): Continuations_GetSomeDataAsync schedules the continuation to the thread pool, outside the ASP.NET request context. This allows the Task returned by Continuations_GetSomeDataAsync to complete without having to re-enter the request context.
  • (test4 and test6): Since the Task is awaited, the ASP.NET request thread is not blocked. This allows AsyncAwait_GetSomeDataAsync to use the ASP.NET request context when it is ready to continue.

And here's the best practices:

  1. In your "library" async methods, use ConfigureAwait(false) whenever possible. In your case, this would change AsyncAwait_GetSomeDataAsync to be var result = await httpClient.GetAsync("", HttpCompletionOption.ResponseHeadersRead).ConfigureAwait(false);
  2. Don't block on Tasks; it's async all the way down. In other words, use await instead of GetResult (Task.Result and Task.Wait should also be replaced with await).

That way, you get both benefits: the continuation (the remainder of the AsyncAwait_GetSomeDataAsync method) is run on a basic thread pool thread that doesn't have to enter the ASP.NET request context; and the controller itself is async (which doesn't block a request thread).

More information:

Update 2012-07-13: Incorporated this answer into a blog post.

How to update (append to) an href in jquery?

$("a.directions-link").attr("href", $("a.directions-link").attr("href")+"...your additions...");

DateTime.Today.ToString("dd/mm/yyyy") returns invalid DateTime Value

Use MM for months. mm is for minutes.


You probably run this code at the begining an hour like (00:00, 05.00, 18.00) and mm gives minutes (00) to your datetime.

From Custom Date and Time Format Strings

"mm" --> The minute, from 00 through 59.

"MM" --> The month, from 01 through 12.

Here is a DEMO. (Which the month part of first line depends on which time do you run this code ;) )

Java: how to import a jar file from command line

You could run it without the -jar command line argument if you happen to know the name of the main class you wish to run:

java -classpath .;myjar.jar;lib/referenced-class.jar my.package.MainClass

If perchance you are using linux, you should use ":" instead of ";" in the classpath.

Row Offset in SQL Server

I would avoid using SELECT *. Specify columns you actually want even though it may be all of them.

SQL Server 2005+

SELECT col1, col2 
    SELECT col1, col2, ROW_NUMBER() OVER (ORDER BY ID) AS RowNum
    FROM MyTable
) AS MyDerivedTable
WHERE MyDerivedTable.RowNum BETWEEN @startRow AND @endRow

SQL Server 2000

Efficiently Paging Through Large Result Sets in SQL Server 2000

A More Efficient Method for Paging Through Large Result Sets

Rerouting stdin and stdout from C

I think you're looking for something like freopen()

Rename specific column(s) in pandas

Use the pandas.DataFrame.rename funtion. Check this link for description.

data.rename(columns = {'gdp': 'log(gdp)'}, inplace = True)

If you intend to rename multiple columns then

data.rename(columns = {'gdp': 'log(gdp)', 'cap': 'log(cap)', ..}, inplace = True)

Google Maps API v3: InfoWindow not sizing correctly

You should give the content to InfoWindow from jQuery object.

var $infoWindowContent = $("<div class='infowin-content'>Content goes here</div>");
var infoWindow = new google.maps.InfoWindow();

Is there a way to view past mysql queries with phpmyadmin?

You just need to click on console at the bottom of the screen in phpMyAdmin and you will get the Executed history:

enter image description here

In Python, what does dict.pop(a,b) mean?

>>> def func(a, *args, **kwargs):
...   print 'a %s, args %s, kwargs %s' % (a, args, kwargs)
>>> func('one', 'two', 'three', four='four', five='five')
a one, args ('two', 'three'), kwargs {'four': 'four', 'five': 'five'}

>>> def anotherfunct(beta, *args):
...   print 'beta %s, args %s' % (beta, args)
>>> def func(a, *args, **kwargs):
...   anotherfunct(a, *args)
>>> func('one', 'two', 'three', four='four', five='five')
beta one, args ('two', 'three')

How to completely uninstall Android Studio from windows(v10)?

I was having problem installing the latest v4.1.2 as it was having issue after I start it it shows my old blank project, so things I did were,

Caution: Please move your sdk and projects to a separate location before following steps if you haven't. So it might save your time downloading sdks and stuff.

1- Uninstall old Android Studio Completely (from Contorl panel -> Programs).

2- Delete this Android Studio Folder located at C:\Users<user_name>\AppData\Local\Google

3- Delete this Android Studio Folder located at C:\Users<user_name>\AppData\Roaming\Google

4- Delete these folders(.android ,.AndroidStudio*, .gradle) located at C:\Users<user_name>\

After doing all this I was managed to have fresh updated Android Studio v4.1.2

show and hide divs based on radio button click

You were pretty close. You're description div tags didn't have the .desc class defined. For your scenario you should have the radio button value equal to the div that you're trying to show.


<div id="myRadioGroup">

    2 Cars<input type="radio" name="cars" checked="checked" value="twoCarDiv"  />

    3 Cars<input type="radio" name="cars" value="threeCarDiv" />

    <div id="twoCarDiv" class="desc">
        2 Cars Selected
    <div id="threeCarDiv" class="desc">
        3 Cars Selected


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

working example:

Regex to check if valid URL that ends in .jpg, .png, or .gif

If you really want to be sure, grabbing the first kilobyte or two of the given URL should be sufficient to determine everything you need to know about the image.

Here's an example of how you can get that information, using Python, and here's an example of it being put to use, as a Django form field which allows you to easily validate an image's existence, filesize, dimensions and format, given its URL.

Drop shadow on a div container?

you might want to try this. Seems to be pretty easy and works on IE6 and Moz atleast.

<div id ="show" style="background-color:Silver;width:100px;height:100px;visibility:visible;border-bottom:outset 1px black;border-right:outset 1px black;" ></div>

The general syntax is : border-[postion]:[border-style] [border-width] [border-color] | inherit

The list of available [border-style]s are :

  • dashed
  • dotted
  • double
  • groove
  • hidden
  • inset
  • none
  • outset
  • ridge
  • solid
  • inherit

Copying files from one directory to another in Java

i use the following code to transfer a uploaded CommonMultipartFile to a folder and copy that file to a destination folder in webapps (i.e) web project folder,

    String resourcepath = "C:/resources/images/" + commonsMultipartFile.getOriginalFilename();

    File file = new File(resourcepath);

    //Copy File to a Destination folder
    File destinationDir = new File("C:/Tomcat/webapps/myProject/resources/images/");
    FileUtils.copyFileToDirectory(file, destinationDir);

Where is the web server root directory in WAMP?

Here's how I get there using Version 3.0.6 on Windows

How to move child element from one parent to another using jQuery

Detach is unnecessary.

The answer (as of 2013) is simple:


According to

You can also select an element on the page and insert it into another:


If an element selected this way is inserted into a single location elsewhere in the DOM, it will be moved into the target (not cloned).

What is the behavior of integer division?

Yes, the result is always truncated towards zero. It will round towards the smallest absolute value.

-5 / 2 = -2
 5 / 2 =  2

For unsigned and non-negative signed values, this is the same as floor (rounding towards -Infinity).

Two constructors

The first line of a constructor is always an invocation to another constructor. You can choose between calling a constructor from the same class with "this(...)" or a constructor from the parent clas with "super(...)". If you don't include either, the compiler includes this line for you: super();

How to compare two JSON have the same properties without order?

Due to @zerkems comment:

i should convert my strings to JSON object and then call the equal method:

var x = eval("(" + remoteJSON + ')');
var y = eval("(" + localJSON + ')');

function jsonequals(x, y) {
    // If both x and y are null or undefined and exactly the same
    if ( x === y ) {
        return true;

    // If they are not strictly equal, they both need to be Objects
    if ( ! ( x instanceof Object ) || ! ( y instanceof Object ) ) {
        return false;

    // They must have the exact same prototype chain, the closest we can do is
    // test the constructor.
    if ( x.constructor !== y.constructor ) {
        return false;

    for ( var p in x ) {
        // Inherited properties were tested using x.constructor === y.constructor
        if ( x.hasOwnProperty( p ) ) {
            // Allows comparing x[ p ] and y[ p ] when set to undefined
            if ( ! y.hasOwnProperty( p ) ) {
                return false;

            // If they have the same strict value or identity then they are equal
            if ( x[ p ] === y[ p ] ) {

            // Numbers, Strings, Functions, Booleans must be strictly equal
            if ( typeof( x[ p ] ) !== "object" ) {
                return false;

            // Objects and Arrays must be tested recursively
            if ( !equals( x[ p ],  y[ p ] ) ) {
                return false;

    for ( p in y ) {
        // allows x[ p ] to be set to undefined
        if ( y.hasOwnProperty( p ) && ! x.hasOwnProperty( p ) ) {
            return false;
    return true;

Mix Razor and Javascript code

A non conventional method to separate javascript from the view, but still use razor in it is to make a Scripts.cshtml file and place your mixed javascript/razor there.


<div id="Result">

<button id="btnLoad">Click me</button>

@section scripts


<script type="text/javascript">
    var url = "@Url.Action("Index", "Home")";

    $(document).ready(function() {
        $("#btnLoad").click(function() {
                type: "POST",
                url: url ,
                data: {someParameter: "some value"},
                contentType: "application/json; charset=utf-8",
                dataType: "json",

                success: function(msg) {

How to make an executable JAR file?

It's too late to answer for this question. But if someone is searching for this answer now I've made it to run with no errors.

First of all make sure to download and add maven to path. [ mvn --version ] will give you version specifications of it if you have added to the path correctly.

Now , add following code to the maven project [ pom.xml ] , in the following code replace with your own main file entry point for eg [ com.example.test.Test ].

            <!-- Build an executable JAR -->
            your_package_to_class_that_contains_main_file .MainFileName</mainClass>

Now go to the command line [CMD] in your project and type mvn package and it will generate a jar file as something like ProjectName-0.0.1-SNAPSHOT.jar under target directory.

Now navigate to the target directory by cd target.

Finally type java -jar jar-file-name.jar and yes this should work successfully if you don't have any errors in your program.

What is the Linux equivalent to DOS pause?

read does this:

user@host:~$ read -n1 -r -p "Press any key to continue..." key

The -n1 specifies that it only waits for a single character. The -r puts it into raw mode, which is necessary because otherwise, if you press something like backslash, it doesn't register until you hit the next key. The -p specifies the prompt, which must be quoted if it contains spaces. The key argument is only necessary if you want to know which key they pressed, in which case you can access it through $key.

If you are using Bash, you can also specify a timeout with -t, which causes read to return a failure when a key isn't pressed. So for example:

read -t5 -n1 -r -p 'Press any key in the next five seconds...' key
if [ "$?" -eq "0" ]; then
    echo 'A key was pressed.'
    echo 'No key was pressed.'

Inject service in app.config

Well, I struggled a little with this one, but I actually did it.

I don't know if the answers are outdated because of some change in angular, but you can do it this way:

This is your service:

.factory('beerRetrievalService', function ($http, $q, $log) {
  return {
    getRandomBeer: function() {
      var deferred = $q.defer();
      var beer = {};

      $'beer-detail', {})
      .then(function(response) {
        beer.beerDetail =;
      function(err) {
        $log.error('Error getting random beer', err);

      return deferred.promise;

And this is the config

.when('/beer-detail', {
  templateUrl : '/beer-detail',
  controller  : 'productDetailController',

  resolve: {
    beer: function(beerRetrievalService) {
      return beerRetrievalService.getRandomBeer();

Regex that accepts only numbers (0-9) and NO characters

Your regex ^[0-9] matches anything beginning with a digit, including strings like "1A". To avoid a partial match, append a $ to the end:


This accepts any number of digits, including none. To accept one or more digits, change the * to +. To accept exactly one digit, just remove the *.

UPDATE: You mixed up the arguments to IsMatch. The pattern should be the second argument, not the first:

if (!System.Text.RegularExpressions.Regex.IsMatch(textbox.Text, "^[0-9]*$"))

CAUTION: In JavaScript, \d is equivalent to [0-9], but in .NET, \d by default matches any Unicode decimal digit, including exotic fare like ? (Myanmar 2) and ? (N'Ko 9). Unless your app is prepared to deal with these characters, stick with [0-9] (or supply the RegexOptions.ECMAScript flag).

Why can't variables be declared in a switch statement?

Interesting that this is fine:

switch (i)  
case 0:  
    int j;  
    j = 7;  

case 1:  

... but this isn't:

switch (i)  
case 0:  
    int j = 7;  

case 1:  

I get that a fix is simple enough, but I'm not understanding yet why the first example doesn't bother the compiler. As was mentioned earlier (2 years earlier hehe), declaration is not what causes the error, even despite the logic. Initialisation is the problem. If the variable is initialised and declared on the different lines, it compiles.

How to convert existing non-empty directory into a Git working directory and push files to a remote repository

Here's my solution:

git init
git remote add origin PATH/TO/REPO
git fetch
git checkout -t origin/master

Insert auto increment primary key to existing table

How to write PHP to ALTER the already existing field (name, in this example) to make it a primary key? W/o, of course, adding any additional 'id' fields to the table..

This a table currently created - Number of Records found: 4 name VARCHAR(20) YES breed VARCHAR(30) YES color VARCHAR(20) YES weight SMALLINT(7) YES

This an end result sought (TABLE DESCRIPTION) -

Number of records found: 4 name VARCHAR(20) NO PRI breed VARCHAR(30) YES color VARCHAR(20) YES weight SMALLINT(7) YES

Instead of getting this -

Number of Records found: 5 id int(11) NO PRI name VARCHAR(20) YES breed VARCHAR(30) YES color VARCHAR(20) YES weight SMALLINT(7) YES

after trying..


how to get this? -

Number of records found: 4 name VARCHAR(20) NO PRI breed VARCHAR(30) YES color VARCHAR(20) YES weight SMALLINT(7) YES

i.e. INSERT/ADD.. etc. the primary key INTO the first field record (w/o adding an additional 'id' field, as stated earlier.

Get Row Index on Rowcommand event

Or, you can use a control class instead of their types:

GridViewRow row = (GridViewRow)(((Control)e.CommandSource).NamingContainer);

int RowIndex = row.RowIndex; 

Set background color in PHP?

You must use CSS. Can't be done with PHP.

How to convert a date String to a Date or Calendar object?


LocalDate.parse( "2015-01-02" )


Java 8 and later has a new java.time framework that makes these other answers outmoded. This framework is inspired by Joda-Time, defined by JSR 310, and extended by the ThreeTen-Extra project. See the Tutorial.

The old bundled classes, java.util.Date/.Calendar, are notoriously troublesome and confusing. Avoid them.


Like Joda-Time, java.time has a class LocalDate to represent a date-only value without time-of-day and without time zone.

ISO 8601

If your input string is in the standard ISO 8601 format of yyyy-MM-dd, you can ask that class to directly parse the string with no need to specify a formatter.

The ISO 8601 formats are used by default in java.time, for both parsing and generating string representations of date-time values.

LocalDate localDate = LocalDate.parse( "2015-01-02" );


If you have a different format, specify a formatter from the java.time.format package. You can either specify your own formatting pattern or let java.time automatically localize as appropriate to a Locale specifying a human language for translation and cultural norms for deciding issues such as period versus comma.

Formatting pattern

Read the DateTimeFormatter class doc for details on the codes used in the format pattern. They vary a bit from the old outmoded java.text.SimpleDateFormat class patterns.

Note how the second argument to the parse method is a method reference, syntax added to Java 8 and later.

String input = "January 2, 2015";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern ( "MMMM d, yyyy" , Locale.US );
LocalDate localDate = LocalDate.parse ( input , formatter );

Dump to console.

System.out.println ( "localDate: " + localDate );

localDate: 2015-01-02

Localize automatically

Or rather than specify a formatting pattern, let java.time localize for you. Call DateTimeFormatter.ofLocalizedDate, and be sure to specify the desired/expected Locale rather than rely on the JVM’s current default which can change at any moment during runtime(!).

String input = "January 2, 2015";
DateTimeFormatter formatter = DateTimeFormatter.ofLocalizedDate ( FormatStyle.LONG );
formatter = formatter.withLocale ( Locale.US );
LocalDate localDate = LocalDate.parse ( input , formatter );

Dump to console.

System.out.println ( "input: " + input + " | localDate: " + localDate );

input: January 2, 2015 | localDate: 2015-01-02

SqlBulkCopy - The given value of type String from the data source cannot be converted to type money of the specified target column

There is another issue you have to take care of it when you try mapping column which is string length, for example TK_NO nvarchar(50) you will have to map to the same length as the destination field.

Why isn't Python very good for functional programming?

One thing that is really important for this question (and the answers) is the following: What the hell is functional programming, and what are the most important properties of it. I'll try to give my view of it:

Functional programming is a lot like writing math on a whiteboard. When you write equations on a whiteboard, you do not think about an execution order. There is (typically) no mutation. You don't come back the day after and look at it, and when you make the calculations again, you get a different result (or you may, if you've had some fresh coffee :)). Basically, what is on the board is there, and the answer was already there when you started writing things down, you just haven't realized what it is yet.

Functional programming is a lot like that; you don't change things, you just evaluate the equation (or in this case, "program") and figure out what the answer is. The program is still there, unmodified. The same with the data.

I would rank the following as the most important features of functional programming: a) referential transparency - if you evaluate the same statement at some other time and place, but with the same variable values, it will still mean the same. b) no side effect - no matter how long you stare at the whiteboard, the equation another guy is looking at at another whiteboard won't accidentally change. c) functions are values too. which can be passed around and applied with, or to, other variables. d) function composition, you can do h=g·f and thus define a new function h(..) which is equivalent to calling g(f(..)).

This list is in my prioritized order, so referential transparency is the most important, followed by no side effects.

Now, if you go through python and check how well the language and libraries supports, and guarantees, these aspects - then you are well on the way to answer your own question.

jQuery scrollTop() doesn't seem to work in Safari or Chrome (Windows)

how about

var top = $('html').scrollTop() || $('body').scrollTop();

How to post ASP.NET MVC Ajax form using JavaScript rather than submit button

Simply place normal button indide Ajax.BeginForm and on click find parent form and normal submit. Ajax form in Razor:

@using (Ajax.BeginForm("AjaxPost", "Home", ajaxOptions))
        <div class="form-group">
            <div class="col-md-12">

                <button class="btn btn-primary" role="button" type="button" onclick="submitParentForm($(this))">Submit parent from Jquery</button>

and Javascript:

function submitParentForm(sender) {
    var $formToSubmit = $(sender).closest('form');


Why is this jQuery click function not working?

Be sure there is nothing on your button (such a div or a trasparent img) that keeps from clicking the button. It sounds stupid, but sometimes we think that jQuery is not working and all that stuffs and the problem is on the positioning of DOM elements.

Column order manipulation using col-lg-push and col-lg-pull in Twitter Bootstrap 3

I just felt like I'll add my $0.2 to those 2 good answers. I had a case when I had to move the last column all the way to the top in a 3-column situation.






Boostrap's class .col-xx-push-Xdoes nothing else but pushes a column to the right with left: XX%; so all you have to do to push a column right is to add the number of pseudo columns going left.

In this case:

  • two columns (col-md-5 and col-md-3) are going left, each with the value of the one that is going right;

  • one(col-md-4) is going right by the sum of the first two going left (5+3=8);

<div class="row">
    <div class="col-md-4 col-md-push-8 ">
    <div class="col-md-5 col-md-pull-4">
    <div class="col-md-3 col-md-pull-4">

enter image description here

Django model "doesn't declare an explicit app_label"

After keep on running into this issue and keep on coming back to this question I thought I'd share what my problem was.

Everything that @Xeberdee is correct so follow that and see if that solves the issue, if not this was my issue:

In my this is what I had:

class AlgoExplainedConfig(AppConfig):
    name = 'algo_explained'
    verbose_name = "Explain_Algo"

And all I did was I added the project name in front of my app name like this:

class AlgoExplainedConfig(AppConfig):
name = '**algorithms_explained**.algo_explained'
verbose_name = "Explain_Algo"

and that solved my problem and I was able to run the makemigrations and migrate command after that! good luck

Share cookie between subdomain and domain

The 2 domains and can only share cookies if the domain is explicitly named in the Set-Cookie header. Otherwise, the scope of the cookie is restricted to the request host. (This is referred to as a "host-only cookie". See What is a host only cookie?)

For instance, if you sent the following header from, then the cookie won't be sent for requests to

Set-Cookie: name=value

However if you use the following, it will be usable on both domains:

Set-Cookie: name=value;

This cookie will be sent for any subdomain of, including nested subdomains like

In RFC 2109, a domain without a leading dot meant that it could not be used on subdomains, and only a leading dot ( would allow it to be used across multiple subdomains (but not the top-level domain, so what you ask was not possible in the older spec).

However, all modern browsers respect the newer specification RFC 6265, and will ignore any leading dot, meaning you can use the cookie on subdomains as well as the top-level domain.

In summary, if you set a cookie like the second example above from, it would be accessible by, and vice versa. This can also be used to allow and to share cookies.

See also:

How to mock private method for testing using PowerMock?

i know a way ny which you can call you private function to test in mockito

    public  void  commandEndHandlerTest() throws  Exception
        Method retryClientDetail_privateMethod =yourclass.class.getDeclaredMethod("Your_function_name",null);
        retryClientDetail_privateMethod.invoke(yourclass.class, null);

Checking if an Android application is running in the background

Offical docs:

The system distinguishes between foreground and background apps. (The definition of background for purposes of service limitations is distinct from the definition used by memory management; an app might be in the background as pertains to memory management, but in the foreground as pertains to its ability to launch services.) An app is considered to be in the foreground if any of the following is true:

  1. It has a visible activity, whether the activity is started or paused.
  2. It has a foreground service.
  3. Another foreground app is connected to the app, either by binding to one of its services or by making use of one of its content providers. For example, the app is in the foreground if another app binds to its:
    • IME
    • Wallpaper service
    • Notification listener
    • Voice or text service

If none of those conditions is true, the app is considered to be in the background.

JQuery wait for page to finish loading before starting the slideshow?

If you pass jQuery a function, it will not run until the page has loaded:

<script type="text/javascript">
$(function() {
    //your header rotation code goes here

Why use Ruby's attr_accessor, attr_reader and attr_writer?

Not all attributes of an object are meant to be directly set from outside the class. Having writers for all your instance variables is generally a sign of weak encapsulation and a warning that you're introducing too much coupling between your classes.

As a practical example: I wrote a design program where you put items inside containers. The item had attr_reader :container, but it didn't make sense to offer a writer, since the only time the item's container should change is when it's placed in a new one, which also requires positioning information.

How do I get the classes of all columns in a data frame?

Hello was looking for the same, and it could be also


How to "set a breakpoint in malloc_error_break to debug"

In your screenshot, you didn't specify any module: try setting "libsystem_c.dylib"

enter image description here

I did that, and it works : breakpoint stops here (although the stacktrace often rise from some obscure system lib...)

JavaScript: Collision detection

This is a simple way that is inefficient, but it's quite reasonable when you don't need anything too complex or you don't have many objects.

Otherwise there are many different algorithms, but most of them are quite complex to implement.

For example, you can use a divide et impera approach in which you cluster objects hierarchically according to their distance and you give to every cluster a bounding box that contains all the items of the cluster. Then you can check which clusters collide and avoid checking pairs of object that belong to clusters that are not colliding/overlapped.

Otherwise, you can figure out a generic space partitioning algorithm to split up in a similar way the objects to avoid useless checks. These kind of algorithms split the collision detection in two phases: a coarse one in which you see what objects maybe colliding and a fine one in which you effectively check single objects. For example, you can use a QuadTree (Wikipedia) to work out an easy solution...

Take a look at the Wikipedia page. It can give you some hints.

Add borders to cells in POI generated Excel File

In the newer apache poi versions:

XSSFCellStyle style = workbook.createCellStyle();