Programs & Examples On #Selectedindex

In HTML DOM, the selectedIndex property sets or returns the index of the selected option in a dropdown list. The index starts at 0.

How to set selected index JComboBox by value

The right way to set an item selected when the combobox is populated by some class' constructor (as @milosz posted):

combobox.getModel().setSelectedItem(new ClassName(parameter1, parameter2));

In your case the code would be:

test.getModel().setSelectedItem(new ComboItem(3, "banana"));

How to set selectedIndex of select element using display text?

Try this:

function SelectAnimal() {
    var sel = document.getElementById('Animals');
    var val = document.getElementById('AnimalToFind').value;
    for(var i = 0, j = sel.options.length; i < j; ++i) {
        if(sel.options[i].innerHTML === val) {
           sel.selectedIndex = i;
           break;
        }
    }
}

What is the proper way to comment functions in Python?

I would go a step further than just saying "use a docstring". Pick a documentation generation tool, such as pydoc or epydoc (I use epydoc in pyparsing), and use the markup syntax recognized by that tool. Run that tool often while you are doing your development, to identify holes in your documentation. In fact, you might even benefit from writing the docstrings for the members of a class before implementing the class.

Make docker use IPv4 for port binding

By default, docker uses AF_INET6 sockets which can be used for both IPv4 and IPv6 connections. This causes netstat to report an IPv6 address for the listening address.

From RedHat https://access.redhat.com/solutions/3114021

Domain Account keeping locking out with correct password every few minutes

I think this highlights a serious deficiency in Windows. We have a (techincal) user account that we use for our system consisting of a windows service and websites, with the app pools configured to run as this user.

Our company has a security policy that after 5 bad passwords, it locks the account out.

Now finding out what locks out the account is practically impossible in a enterprise. When the account is locked out, the AD server should log from what process and what server caused the lock out.

I've looked into it and it (lock out tools) and it doesnt do this. only possible thing is a tool but you have to run it on the server and wait to see if any process is doing it. But in a enterprise with 1000s of servers thats impossible, you have to guess. Its crazy.

JQuery - File attributes

Just try

var file = $("#uploadedfile").prop("files")[0];
var fileName = file.name;
var fileSize = file.size;
alert("Uploading: "+fileName+" @ "+fileSize+"bytes");

It worked for me

Print out the values of a (Mat) matrix in OpenCV C++

See the first answer to Accessing a matrix element in the "Mat" object (not the CvMat object) in OpenCV C++
Then just loop over all the elements in cout << M.at<double>(0,0); rather than just 0,0

Or better still with the C++ interface:

cv::Mat M;
cout << "M = " << endl << " "  << M << endl << endl;

How to set connection timeout with OkHttp

For Retrofit retrofit:2.0.0-beta4 the code goes as follows:

OkHttpClient client = new OkHttpClient.Builder()
    .addInterceptor(logging)
    .connectTimeout(30, TimeUnit.SECONDS)
    .readTimeout(30, TimeUnit.SECONDS)
    .writeTimeout(30, TimeUnit.SECONDS)
    .build();

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("http://api.yourapp.com/")
    .addConverterFactory(GsonConverterFactory.create())
    .client(client)
    .build();

django import error - No module named core.management

Another possible reason for this problem is that your OS runs python3 by default.

Either you have to explicitly do: python2 manage.py

or you need to edit the shebang of manage.py, like so:

#!/usr/bin/env python2

or if you are using python3:

#!/usr/bin/env python3

Is it possible to set UIView border properties from interface builder?

You can make a category of UIView and add this in .h file of category

@property (nonatomic) IBInspectable UIColor *borderColor;
@property (nonatomic) IBInspectable CGFloat borderWidth;
@property (nonatomic) IBInspectable CGFloat cornerRadius;

Now add this in .m file

@dynamic borderColor,borderWidth,cornerRadius;

and this as well in . m file

-(void)setBorderColor:(UIColor *)borderColor{
    [self.layer setBorderColor:borderColor.CGColor];
}

-(void)setBorderWidth:(CGFloat)borderWidth{
    [self.layer setBorderWidth:borderWidth];
}

-(void)setCornerRadius:(CGFloat)cornerRadius{
    [self.layer setCornerRadius:cornerRadius];
}

now you will see this in your storyboard for all UIView subclasses (UILabel, UITextField, UIImageView etc)

enter image description here

Thats it.. No Need to import category anywhere, just add the category's files in the project and see these properties in the storyboard.

Powershell remoting with ip-address as target

The guys have given the simple solution, which will do be you should have a look at the help - it's good, looks like a lot in one go but it's actually quick to read:

get-help about_Remote_Troubleshooting | more

How to set focus on input field?

I found it useful to use a general expression. This way you can do stuff like automatically move focus when input text is valid

<button type="button" moo-focus-expression="form.phone.$valid">

Or automatically focus when the user completes a fixed length field

<button type="submit" moo-focus-expression="smsconfirm.length == 6">

And of course focus after load

<input type="text" moo-focus-expression="true">

The code for the directive:

.directive('mooFocusExpression', function ($timeout) {
    return {
        restrict: 'A',
        link: {
            post: function postLink(scope, element, attrs) {
                scope.$watch(attrs.mooFocusExpression, function (value) {

                    if (attrs.mooFocusExpression) {
                        if (scope.$eval(attrs.mooFocusExpression)) {
                            $timeout(function () {
                                element[0].focus();
                            }, 100); //need some delay to work with ng-disabled
                        }
                    }
                });
            }
        }
    };
});

What is the Sign Off feature in Git for?

git 2.7.1 (February 2016) clarifies that in commit b2c150d (05 Jan 2016) by David A. Wheeler (david-a-wheeler).
(Merged by Junio C Hamano -- gitster -- in commit 7aae9ba, 05 Feb 2016)

git commit man page now includes:

-s::
--signoff::

Add Signed-off-by line by the committer at the end of the commit log message.
The meaning of a signoff depends on the project, but it typically certifies that committer has the rights to submit this work under the same license and agrees to a Developer Certificate of Origin (see https://developercertificate.org for more information).


Expand documentation describing --signoff

Modify various document (man page) files to explain in more detail what --signoff means.

This was inspired by "lwn article 'Bottomley: A modest proposal on the DCO'" (Developer Certificate of Origin) where paulj noted:

The issue I have with DCO is that there adding a "-s" argument to git commit doesn't really mean you have even heard of the DCO (the git commit man page makes no mention of the DCO anywhere), never mind actually seen it.

So how can the presence of "signed-off-by" in any way imply the sender is agreeing to and committing to the DCO? Combined with fact I've seen replies on lists to patches without SOBs that say nothing more than "Resend this with signed-off-by so I can commit it".

Extending git's documentation will make it easier to argue that developers understood --signoff when they use it.


Note that this signoff is now (for Git 2.15.x/2.16, Q1 2018) available for git pull as well.

See commit 3a4d2c7 (12 Oct 2017) by W. Trevor King (wking).
(Merged by Junio C Hamano -- gitster -- in commit fb4cd88, 06 Nov 2017)

pull: pass --signoff/--no-signoff to "git merge"

merge can take --signoff, but without pull passing --signoff down, it is inconvenient to use; allow 'pull' to take the option and pass it through.

What is the difference between an expression and a statement in Python?

Python calls expressions "expression statements", so the question is perhaps not fully formed.

A statement consists of pretty much anything you can do in Python: calculating a value, assigning a value, deleting a variable, printing a value, returning from a function, raising an exception, etc. The full list is here: http://docs.python.org/reference/simple_stmts.html#

An expression statement is limited to calling functions (e.g., math.cos(theta)"), operators ( e.g., "2+3"), etc. to produce a value.

Unlink of file Failed. Should I try again?

Worked for me, Tried on windows:

Stop your server running from IDE or close your IDE

Intellij/Ecllipse or any, it will work.

How to convert hex string to Java string?

First of all read in the data, then convert it to byte array:

 byte b = Byte.parseByte(str, 16); 

and then use String constructor:

new String(byte[] bytes) 

or if the charset is not system default then:

new String(byte[] bytes, String charsetName) 

How can I do division with variables in a Linux shell?

Referencing Bash Variables Requires Parameter Expansion

The default shell on most Linux distributions is Bash. In Bash, variables must use a dollar sign prefix for parameter expansion. For example:

x=20
y=5
expr $x / $y

Of course, Bash also has arithmetic operators and a special arithmetic expansion syntax, so there's no need to invoke the expr binary as a separate process. You can let the shell do all the work like this:

x=20; y=5
echo $((x / y))

TypeError: $ is not a function when calling jQuery function

You come across this issue when your function name and one of the id names in the file are same. just make sure all your id names in the file are unique.

Check if a string is a valid Windows directory (folder) path

A simpler OS-independent solution:

Go ahead and attempt to create the actual directory; if there is an issue or the name is invalid, the OS will automatically complain and the code will throw.

public static class PathHelper
{
    public static void ValidatePath(string path)
    {
        if (!Directory.Exists(path))
            Directory.CreateDirectory(path).Delete();
    }
}

Usage:

try
{
    PathHelper.ValidatePath(path);
}
catch(Exception e)
{
    // handle exception
}

Directory.CreateDirectory() will automatically throw in all of the following situations:

System.IO.IOException:
The directory specified by path is a file. -or- The network name is not known.

System.UnauthorizedAccessException:
The caller does not have the required permission.

System.ArgumentException:
path is a zero-length string, contains only white space, or contains one or more invalid characters. You can query for invalid characters by using the System.IO.Path.GetInvalidPathChars method. -or- path is prefixed with, or contains, only a colon character (:).

System.ArgumentNullException:
path is null.

System.IO.PathTooLongException:
The specified path, file name, or both exceed the system-defined maximum length.

System.IO.DirectoryNotFoundException:
The specified path is invalid (for example, it is on an unmapped drive).

System.NotSupportedException:
path contains a colon character (:) that is not part of a drive label ("C:").

How to create an 2D ArrayList in java?

I want to create a 2D array that each cell is an ArrayList!

If you want to create a 2D array of ArrayList.Then you can do this :

ArrayList[][] table = new ArrayList[10][10];
table[0][0] = new ArrayList(); // add another ArrayList object to [0,0]
table[0][0].add(); // add object to that ArrayList

ReactJS Two components communicating

I saw that the question is already answered, but if you'd like to learn more details, there are a total of 3 cases of communication between components:

  • Case 1: Parent to Child communication
  • Case 2: Child to Parent communication
  • Case 3: Not-related components (any component to any component) communication

How to detect the screen resolution with JavaScript?

var width = screen.width;
var height = screen.height;

How do I configure PyCharm to run py.test tests?

Please go to File| Settings | Tools | Python Integrated Tools and change the default test runner to py.test. Then you'll get the py.test option to create tests instead of the unittest one.

How can I open two pages from a single click without using JavaScript?

it is working perfectly by only using html

<p><a href="#"onclick="window.open('http://google.com');window.open('http://yahoo.com');">Click to open Google and Yahoo</a></p>

Saving a select count(*) value to an integer (SQL Server)

If @myInt is zero it means no rows in the table: it would be NULL if never set at all.

COUNT will always return a row, even for no rows in a table.

Edit, Apr 2012: the rules for this are described in my answer here:Does COUNT(*) always return a result?

Your count/assign is correct but could be either way:

select @myInt = COUNT(*) from myTable
set @myInt = (select COUNT(*) from myTable)

However, if you are just looking for the existence of rows, (NOT) EXISTS is more efficient:

IF NOT EXISTS (SELECT * FROM myTable)

accessing a file using [NSBundle mainBundle] pathForResource: ofType:inDirectory:

After following @Neelam Verma's answer or @dawid's answer, which has the same end result as @Neelam Verma's answer, difference being that @dawid's answer starts with the drag and drop of the file into the Xcode project and @Neelam Verma's answer starts with a file already a part of the Xcode project, I still could not get NSBundle.mainBundle().pathForResource("file-title", ofType:"type") to find my video file.

I thought maybe because I had my file was in a Group nested in the Xcode project that this was the cause, so I moved the video file to the root of my Xcode project, still no luck, this was my code:

 guard let path = NSBundle.mainBundle().pathForResource("testVid1", ofType:"mp4") else {
        print("Invalid video path")
        return
    }

Originally, this was the name of my file: testVid1.MP4, renaming the video file to testVid1.mp4 fixed my issue, so, at least the ofType string argument is case sensitive.

Convert Xml to Table SQL Server

This is the answer, hope it helps someone :)

First there are two variations on how the xml can be written:

1

<row>
    <IdInvernadero>8</IdInvernadero>
    <IdProducto>3</IdProducto>
    <IdCaracteristica1>8</IdCaracteristica1>
    <IdCaracteristica2>8</IdCaracteristica2>
    <Cantidad>25</Cantidad>
    <Folio>4568457</Folio>
</row>
<row>
    <IdInvernadero>3</IdInvernadero>
    <IdProducto>3</IdProducto>
    <IdCaracteristica1>1</IdCaracteristica1>
    <IdCaracteristica2>2</IdCaracteristica2>
    <Cantidad>72</Cantidad>
    <Folio>4568457</Folio>
</row>

Answer:

SELECT  
       Tbl.Col.value('IdInvernadero[1]', 'smallint'),  
       Tbl.Col.value('IdProducto[1]', 'smallint'),  
       Tbl.Col.value('IdCaracteristica1[1]', 'smallint'),
       Tbl.Col.value('IdCaracteristica2[1]', 'smallint'),
       Tbl.Col.value('Cantidad[1]', 'int'),
       Tbl.Col.value('Folio[1]', 'varchar(7)')
FROM   @xml.nodes('//row') Tbl(Col)  

2.

<row IdInvernadero="8" IdProducto="3" IdCaracteristica1="8" IdCaracteristica2="8" Cantidad ="25" Folio="4568457" />                         
<row IdInvernadero="3" IdProducto="3" IdCaracteristica1="1" IdCaracteristica2="2" Cantidad ="72" Folio="4568457" />

Answer:

SELECT  
       Tbl.Col.value('@IdInvernadero', 'smallint'),  
       Tbl.Col.value('@IdProducto', 'smallint'),  
       Tbl.Col.value('@IdCaracteristica1', 'smallint'),
       Tbl.Col.value('@IdCaracteristica2', 'smallint'),
       Tbl.Col.value('@Cantidad', 'int'),
       Tbl.Col.value('@Folio', 'varchar(7)')

FROM   @xml.nodes('//row') Tbl(Col)

Taken from:

  1. http://kennyshu.blogspot.com/2007/12/convert-xml-file-to-table-in-sql-2005.html

  2. http://msdn.microsoft.com/en-us/library/ms345117(SQL.90).aspx

Responsive width Facebook Page Plugin

Don't forget the data-href field! For me comments were working without it but were not responsive. And of course data-width='100%'

Jquery $.ajax fails in IE on cross domain calls

Simply install this jQuery Plugin: jQuery Cross-Domain AJAX for IE8

This 1.4kb plugin works right away in Internet Explorer 8 and 9.

Include the plugin after jQuery, and call your ajax request as normal. Nothing else required.

In Go's http package, how do I get the query string on a POST request?

There are two ways of getting query params:

  1. Using reqeust.URL.Query()
  2. Using request.Form

In second case one has to be careful as body parameters will take precedence over query parameters. A full description about getting query params can be found here

https://golangbyexample.com/net-http-package-get-query-params-golang

Why rgb and not cmy?

The basic colours are RGB not RYB. Yes most of the softwares use the traditional RGB which can be used to mix together to form any other color i.e. RGB are the fundamental colours (as defined in Physics & Chemistry texts).

The printer user CMYK (cyan, magenta, yellow, and black) coloring as said by @jcomeau_ictx. You can view the following article to know about RGB vs CMYK: RGB Vs CMYK

A bit more information from the extract about them:

Red, Green, and Blue are "additive colors". If we combine red, green and blue light you will get white light. This is the principal behind the T.V. set in your living room and the monitor you are staring at now. Additive color, or RGB mode, is optimized for display on computer monitors and peripherals, most notably scanning devices.

Cyan, Magenta and Yellow are "subtractive colors". If we print cyan, magenta and yellow inks on white paper, they absorb the light shining on the page. Since our eyes receive no reflected light from the paper, we perceive black... in a perfect world! The printing world operates in subtractive color, or CMYK mode.

How to get current working directory using vba?

I've tested this:

When I open an Excel document D:\db\tmp\test1.xlsm:

  • CurDir() returns C:\Users\[username]\Documents

  • ActiveWorkbook.Path returns D:\db\tmp

So CurDir() has a system default and can be changed.

ActiveWorkbook.Path does not change for the same saved Workbook.

For example, CurDir() changes when you do "File/Save As" command, and select a random directory in the File/Directory selection dialog. Then click on Cancel to skip saving. But CurDir() has already changed to the last selected directory.

How to add/subtract time (hours, minutes, etc.) from a Pandas DataFrame.Index whos objects are of type datetime.time?

The Philippe solution but cleaner:

My subtraction data is: '2018-09-22T11:05:00.000Z'

import datetime
import pandas as pd

df_modified = pd.to_datetime(df_reference.index.values) - datetime.datetime(2018, 9, 22, 11, 5, 0)

Error message "Linter pylint is not installed"

Check the path Pylint has been installed to, by typing which pylint on your terminal.

You will get something like: /usr/local/bin/pylint

Copy it.

Go to your Visual Studio Code settings in the preferences tab and find the line that goes

"python.linting.pylintPath": "pylint"

Edit the line to be

"python.linting.pylintPath": "/usr/local/bin/pylint",

replacing the value "pylint" with the path you got from typing which pylint.

Save your changes and reload Visual Studio Code.

How to get UTC timestamp in Ruby?

You could use: Time.now.to_i.

Unresolved Import Issues with PyDev and Eclipse

I fixed my pythonpath and everything was dandy when I imported stuff through the console, but all these previously unresolved imports were still marked as errors in my code, no matter how many times I restarted eclipse or refreshed/cleaned the project.

I right clicked the project->Pydev->Remove error markers and it got rid of that problem. Don't worry, if your code contains actual errors they will be re-marked.

Should we pass a shared_ptr by reference or by value?

Since C++11 you should take it by value over const& more often than you might think.

If you are taking the std::shared_ptr (rather than the underlying type T), then you are doing so because you want to do something with it.

If you would like to copy it somewhere, it makes more sense to take it by copy, and std::move it internally, rather than taking it by const& and then later copying it. This is because you allow the caller the option to in turn std::move the shared_ptr when calling your function, thus saving yourself a set of increment and decrement operations. Or not. That is, the caller of the function can decide whether or not he needs the std::shared_ptr around after calling the function, and depending on whether or not move or not. This is not achievable if you pass by const&, and thus it is then preferably to take it by value.

Of course, if the caller both needs his shared_ptr around for longer (thus can not std::move it) and you don't want to create a plain copy in the function (say you want a weak pointer, or you only sometimes want to copy it, depending on some condition), then a const& might still be preferable.

For example, you should do

void enqueue(std::shared<T> t) m_internal_queue.enqueue(std::move(t));

over

void enqueue(std::shared<T> const& t) m_internal_queue.enqueue(t);

Because in this case you always create a copy internally

Simplest two-way encryption using PHP

Encrypting using openssl_encrypt() The openssl_encrypt function provides a secured and easy way to encrypt your data.

In the script below, we use the AES128 encryption method, but you may consider other kind of encryption method depending on what you want to encrypt.

<?php
$message_to_encrypt = "Yoroshikune";
$secret_key = "my-secret-key";
$method = "aes128";
$iv_length = openssl_cipher_iv_length($method);
$iv = openssl_random_pseudo_bytes($iv_length);

$encrypted_message = openssl_encrypt($message_to_encrypt, $method, $secret_key, 0, $iv);

echo $encrypted_message;
?>

Here is an explanation of the variables used :

message_to_encrypt : the data you want to encrypt secret_key : it is your ‘password’ for encryption. Be sure not to choose something too easy and be careful not to share your secret key with other people method : the method of encryption. Here we chose AES128. iv_length and iv : prepare the encryption using bytes encrypted_message : the variable including your encrypted message

Decrypting using openssl_decrypt() Now you encrypted your data, you may need to decrypt it in order to re-use the message you first included into a variable. In order to do so, we will use the function openssl_decrypt().

<?php
$message_to_encrypt = "Yoroshikune";
$secret_key = "my-secret-key";
$method = "aes128";
$iv_length = openssl_cipher_iv_length($method);
$iv = openssl_random_pseudo_bytes($iv_lenght);
$encrypted_message = openssl_encrypt($message_to_encrypt, $method, $secret_key, 0, $iv);

$decrypted_message = openssl_decrypt($encrypted_message, $method, $secret_key, 0, $iv);

echo $decrypted_message;
?>

The decrypt method proposed by openssl_decrypt() is close to openssl_encrypt().

The only difference is that instead of adding $message_to_encrypt, you will need to add your already encrypted message as the first argument of openssl_decrypt().

That is all you have to do.

How do I implement interfaces in python?

Something like this (might not work as I don't have Python around):

class IInterface:
    def show(self): raise NotImplementedError

class MyClass(IInterface):
    def show(self): print "Hello World!"

How to calculate the running time of my program?

Beside the well-known (and already mentioned) System.currentTimeMillis() and System.nanoTime() there is also a neat library called perf4j which might be useful too, depending on your purpose of course.

How to fix "unable to write 'random state' " in openssl

I did not find where the .rnd file is so I ran the cmd as administrator and it worked like a charm.

How to check if user input is not an int value

Taken from a related post:

public static boolean isInteger(String s) {
    try { 
        Integer.parseInt(s); 
    } catch(NumberFormatException e) { 
        return false; 
    }
    // only got here if we didn't return false
    return true;
}

DB2 SQL error: SQLCODE: -206, SQLSTATE: 42703

That only means that an undefined column or parameter name was detected. The errror that DB2 gives should point what that may be:

DB2 SQL Error: SQLCODE=-206, SQLSTATE=42703, SQLERRMC=[THE_UNDEFINED_COLUMN_OR_PARAMETER_NAME], DRIVER=4.8.87

Double check your table definition. Maybe you just missed adding something.

I also tried google-ing this problem and saw this:

http://www.coderanch.com/t/515475/JDBC/databases/sql-insert-statement-giving-sqlcode

How to configure "Shorten command line" method for whole project in IntelliJ

The latest 2020 build doesn't have the shorten command line option by default we need to add that option from the configuration.

Run > Edit Configurations > Select the corresponding run configuration and click on Modify options for adding the shorten command-line configuration to the UI. enter image description here

Select the shorten command line option enter image description here

Now choose jar manifest from the shorten command line option enter image description here

Adding 'serial' to existing column in Postgres

Look at the following commands (especially the commented block).

DROP TABLE foo;
DROP TABLE bar;

CREATE TABLE foo (a int, b text);
CREATE TABLE bar (a serial, b text);

INSERT INTO foo (a, b) SELECT i, 'foo ' || i::text FROM generate_series(1, 5) i;
INSERT INTO bar (b) SELECT 'bar ' || i::text FROM generate_series(1, 5) i;

-- blocks of commands to turn foo into bar
CREATE SEQUENCE foo_a_seq;
ALTER TABLE foo ALTER COLUMN a SET DEFAULT nextval('foo_a_seq');
ALTER TABLE foo ALTER COLUMN a SET NOT NULL;
ALTER SEQUENCE foo_a_seq OWNED BY foo.a;    -- 8.2 or later

SELECT MAX(a) FROM foo;
SELECT setval('foo_a_seq', 5);  -- replace 5 by SELECT MAX result

INSERT INTO foo (b) VALUES('teste');
INSERT INTO bar (b) VALUES('teste');

SELECT * FROM foo;
SELECT * FROM bar;

get name of a variable or parameter

Alternatively,

1) Without touching System.Reflection namespace,

GETNAME(new { myInput });

public static string GETNAME<T>(T myInput) where T : class
{
    if (myInput == null)
        return string.Empty;

    return myInput.ToString().TrimStart('{').TrimEnd('}').Split('=')[0].Trim();
}

2) The below one can be faster though (from my tests)

GETNAME(new { variable });
public static string GETNAME<T>(T myInput) where T : class
{
    if (myInput == null)
        return string.Empty;

    return typeof(T).GetProperties()[0].Name;
}

You can also extend this for properties of objects (may be with extension methods):

new { myClass.MyProperty1 }.GETNAME();

You can cache property values to improve performance further as property names don't change during runtime.

The Expression approach is going to be slower for my taste. To get parameter name and value together in one go see this answer of mine

Counting unique values in a column in pandas dataframe like in Qlik?

you can use unique property by using len function

len(df['hID'].unique()) 5

Check if current directory is a Git repository

if ! [[ $(pwd) = *.git/* || $(pwd) = *.git ]]; then 
  if type -P git >/dev/null; then
    ! git rev-parse --is-inside-work-tree >/dev/null 2>&1 || {
     printf '\n%s\n\n' "GIT repository detected." && git status
    }
  fi
fi

Thank you ivan_pozdeev, Now I have a test if inside the .git directory the code will not run so no errors printed out or false exit status.

The "! [[ $(pwd) = .git/ || $(pwd) = *.git ]]" tests if you're not inside a .git repo then it will run the git command. The builtin type command is use to check if you have git installed or it is within your PATH. see help type

Examples of good gotos in C or C++

I don't use goto's myself, however I did work with a person once that would use them in specific cases. If I remember correctly, his rationale was around performance issues - he also had specific rules for how. Always in the same function, and the label was always BELOW the goto statement.

How to write the code for the back button?

You need to tell the browser you are using javascript:

<a href="javascript:history.back(1)">Back</a> 

Also, your input element seems out of place in your code.

Regular expression to match DNS hostname or IP Address?

how about this?

([0-9]{1,3}\.){3}[0-9]{1,3}

.Contains() on a list of custom class objects

You need to create a object from your list like:

List<CartProduct> lst = new List<CartProduct>();

CartProduct obj = lst.Find(x => (x.Name == "product name"));

That object get the looked value searching by their properties: x.name

Then you can use List methods like Contains or Remove

if (lst.Contains(obj))
{
   lst.Remove(obj);
}

Find the number of downloads for a particular app in apple appstore

I think developers can do this for their own apps via iTunes Connect but this doesn't help you if you are looking for stats on other peoples apps.

148Apps also have some aggregate AppStore metrics on their web site that could be useful to you but, again, doesn't really give a low-level breakdown of numbers.

You could also scrape some stats from the RSS feeds generated by the iTunes Store RSS Generator but, again, this just gets currently popular apps rather than actual download numbers.

Node.js global proxy setting

Unfortunately, it seems that proxy information must be set on each call to http.request. Node does not include a mechanism for global proxy settings.

The global-tunnel-ng module on NPM appears to handle this, however:

var globalTunnel = require('global-tunnel-ng');

globalTunnel.initialize({
  host: '10.0.0.10',
  port: 8080,
  proxyAuth: 'userId:password', // optional authentication
  sockets: 50 // optional pool size for each http and https
});

After the global settings are establish with a call to initialize, both http.request and the request library will use the proxy information.

The module can also use the http_proxy environment variable:

process.env.http_proxy = 'http://proxy.example.com:3129';
globalTunnel.initialize();

Default port for SQL Server

The default, unnamed instance always gets port 1433 for TCP. UDP port 1434 is used by the SQL Browser service to allow named instances to be located. In SQL Server 2000 the first instance to be started took this role.

Non-default instances get their own dynamically-allocated port, by default. If necessary, for example to configure a firewall, you can set them explicitly. If you don't want to enable or allow access to SQL Browser, you have to either include the instance's port number in the connection string, or set it up with the Alias tab in cliconfg (SQL Server Client Network Utility) on each client machine.

For more information see SQL Server Browser Service on MSDN.

Xamarin.Forms ListView: Set the highlight color of a tapped item

Here is the purely cross platform and neat way:

1) Define a trigger action

namespace CustomTriggers {
   public class DeselectListViewItemAction:TriggerAction<ListView> {
       protected override void Invoke(ListView sender) {
                sender.SelectedItem = null;
       }
   }
}

2) Apply the above class instance as an EventTrigger action in XAML as below

 <ListView x:Name="YourListView" ItemsSource="{Binding ViewModelItems}">
    <ListView.Triggers>
        <EventTrigger Event="ItemSelected">
            <customTriggers:DeselectListViewItemAction></customTriggers:DeselectListViewItemAction>
        </EventTrigger>
    </ListView.Triggers>
</ListView>

Don't forget to add xmlns:customTriggers="clr-namespace:CustomTriggers;assembly=ProjectAssembly"

Note: Because none of your items are in selected mode, selection styling will not get applied on either of the platforms.

Case-insensitive string comparison in C++

Take advantage of the standard char_traits. Recall that a std::string is in fact a typedef for std::basic_string<char>, or more explicitly, std::basic_string<char, std::char_traits<char> >. The char_traits type describes how characters compare, how they copy, how they cast etc. All you need to do is typedef a new string over basic_string, and provide it with your own custom char_traits that compare case insensitively.

struct ci_char_traits : public char_traits<char> {
    static bool eq(char c1, char c2) { return toupper(c1) == toupper(c2); }
    static bool ne(char c1, char c2) { return toupper(c1) != toupper(c2); }
    static bool lt(char c1, char c2) { return toupper(c1) <  toupper(c2); }
    static int compare(const char* s1, const char* s2, size_t n) {
        while( n-- != 0 ) {
            if( toupper(*s1) < toupper(*s2) ) return -1;
            if( toupper(*s1) > toupper(*s2) ) return 1;
            ++s1; ++s2;
        }
        return 0;
    }
    static const char* find(const char* s, int n, char a) {
        while( n-- > 0 && toupper(*s) != toupper(a) ) {
            ++s;
        }
        return s;
    }
};

typedef std::basic_string<char, ci_char_traits> ci_string;

The details are on Guru of The Week number 29.

How to search and replace text in a file?

You can also use pathlib.

from pathlib2 import Path
path = Path(file_to_search)
text = path.read_text()
text = text.replace(text_to_search, replacement_text)
path.write_text(text)

How do I create a view controller file after creating a new view controller?

To add new ViewController once you have have an existing ViewController, follow below step:

  1. Click on background of Main.storyboard.

  2. Search and select ViewController from object library at the utility window.

  3. Drag and drop it in background to create a new ViewController.

Git push won't do anything (everything up-to-date)

Right now, it appears as you are on the develop branch. Do you have a develop branch on your origin? If not, try git push origin develop. git push will work once it knows about a develop branch on your origin.

As further reading, I'd have a look at the git-push man pages, in particular, the examples section.

How to delete a cookie?

You can do this by setting the date of expiry to yesterday.

Setting it to "-1" doesn't work. That marks a cookie as a Sessioncookie.

Python - difference between two strings

You can use ndiff in the difflib module to do this. It has all the information necessary to convert one string into another string.

A simple example:

import difflib

cases=[('afrykanerskojezyczny', 'afrykanerskojezycznym'),
       ('afrykanerskojezyczni', 'nieafrykanerskojezyczni'),
       ('afrykanerskojezycznym', 'afrykanerskojezyczny'),
       ('nieafrykanerskojezyczni', 'afrykanerskojezyczni'),
       ('nieafrynerskojezyczni', 'afrykanerskojzyczni'),
       ('abcdefg','xac')] 

for a,b in cases:     
    print('{} => {}'.format(a,b))  
    for i,s in enumerate(difflib.ndiff(a, b)):
        if s[0]==' ': continue
        elif s[0]=='-':
            print(u'Delete "{}" from position {}'.format(s[-1],i))
        elif s[0]=='+':
            print(u'Add "{}" to position {}'.format(s[-1],i))    
    print()      

prints:

afrykanerskojezyczny => afrykanerskojezycznym
Add "m" to position 20

afrykanerskojezyczni => nieafrykanerskojezyczni
Add "n" to position 0
Add "i" to position 1
Add "e" to position 2

afrykanerskojezycznym => afrykanerskojezyczny
Delete "m" from position 20

nieafrykanerskojezyczni => afrykanerskojezyczni
Delete "n" from position 0
Delete "i" from position 1
Delete "e" from position 2

nieafrynerskojezyczni => afrykanerskojzyczni
Delete "n" from position 0
Delete "i" from position 1
Delete "e" from position 2
Add "k" to position 7
Add "a" to position 8
Delete "e" from position 16

abcdefg => xac
Add "x" to position 0
Delete "b" from position 2
Delete "d" from position 4
Delete "e" from position 5
Delete "f" from position 6
Delete "g" from position 7

An implementation of the fast Fourier transform (FFT) in C#

AForge.net is a free (open-source) library with Fast Fourier Transform support. (See Sources/Imaging/ComplexImage.cs for usage, Sources/Math/FourierTransform.cs for implemenation)

XmlWriter to Write to a String Instead of to a File

Well I think the simplest and fastest solution here would be just to:

StringBuilder sb = new StringBuilder();

using (var writer = XmlWriter.Create(sb, settings))
{
    ... // Whatever code you have/need :)

    sb = sb.Replace("encoding=\"utf-16\"", "encoding=\"utf-8\""); //Or whatever uft you want/use.
    //Before you finally save it:
    File.WriteAllText("path\\dataName.xml", sb.ToString());
}

How do I edit an incorrect commit message in git ( that I've pushed )?

The message from Linus Torvalds may answer your question:

Modify/edit old commit messages

Short answer: you can not (if pushed).


extract (Linus refers to BitKeeper as BK):

Side note, just out of historical interest: in BK you could.

And if you're used to it (like I was) it was really quite practical. I would apply a patch-bomb from Andrew, notice something was wrong, and just edit it before pushing it out.

I could have done the same with git. It would have been easy enough to make just the commit message not be part of the name, and still guarantee that the history was untouched, and allow the "fix up comments later" thing.

But I didn't.

Part of it is purely "internal consistency". Git is simply a cleaner system thanks to everything being SHA1-protected, and all objects being treated the same, regardless of object type. Yeah, there are four different kinds of objects, and they are all really different, and they can't be used in the same way, but at the same time, even if their encoding might be different on disk, conceptually they all work exactly the same.

But internal consistency isn't really an excuse for being inflexible, and clearly it would be very flexible if we could just fix up mistakes after they happen. So that's not a really strong argument.

The real reason git doesn't allow you to change the commit message ends up being very simple: that way, you can trust the messages. If you allowed people to change them afterwards, the messages are inherently not very trustworthy.


To be complete, you could rewrite your local commit history in order to reflect what you want, as suggested by sykora (with some rebase and reset --hard, gasp!)

However, once you publish your revised history again (with a git push origin +master:master, the + sign forcing the push to occur, even if it doesn't result in a "fast-forward" commit)... you might get into some trouble.

Extract from this other SO question:

I actually once pushed with --force to git.git repository and got scolded by Linus BIG TIME. It will create a lot of problems for other people. A simple answer is "don't do it".

How can I maintain fragment state when added to the back stack?

Replace a Fragment using following code:

Fragment fragment = new AddPaymentFragment();
getSupportFragmentManager().beginTransaction().replace(R.id.frame, fragment, "Tag_AddPayment")
                .addToBackStack("Tag_AddPayment")
                .commit();

Activity's onBackPressed() is :

  @Override
public void onBackPressed() {
    android.support.v4.app.FragmentManager fm = getSupportFragmentManager();
    if (fm.getBackStackEntryCount() > 1) {

        fm.popBackStack();
    } else {


        finish();

    }
    Log.e("popping BACKSTRACK===> ",""+fm.getBackStackEntryCount());

}

Can you have multiple $(document).ready(function(){ ... }); sections?

Yes you can easily have multiple blocks. Just be careful with dependencies between them as the evaluation order might not be what you expect.

round value to 2 decimals javascript

If you want it visually formatted to two decimals as a string (for output) use toFixed():

var priceString = someValue.toFixed(2);

The answer by @David has two problems:

  1. It leaves the result as a floating point number, and consequently holds the possibility of displaying a particular result with many decimal places, e.g. 134.1999999999 instead of "134.20".

  2. If your value is an integer or rounds to one tenth, you will not see the additional decimal value:

    var n = 1.099;
    (Math.round( n * 100 )/100 ).toString() //-> "1.1"
    n.toFixed(2)                            //-> "1.10"
    
    var n = 3;
    (Math.round( n * 100 )/100 ).toString() //-> "3"
    n.toFixed(2)                            //-> "3.00"
    

And, as you can see above, using toFixed() is also far easier to type. ;)

SelectedValue vs SelectedItem.Value of DropDownList

In droupDown list there are two item add property.

1) Text 2) value

If you want to get text property then u use selecteditem.text

and If you want to select value property then use selectedvalue property

In your case i thing both value and text property are the same so no matter if u use selectedvalue or selecteditem.text

If both are different then they give us different results

Conditional Count on a field

Using COUNT instead of SUM removes the requirement for an ELSE statement:

SELECT jobId, jobName,
    COUNT(CASE WHEN Priority=1 THEN 1 END) AS Priority1,
    COUNT(CASE WHEN Priority=2 THEN 1 END) AS Priority2,
    COUNT(CASE WHEN Priority=3 THEN 1 END) AS Priority3,
    COUNT(CASE WHEN Priority=4 THEN 1 END) AS Priority4,
    COUNT(CASE WHEN Priority=5 THEN 1 END) AS Priority5
FROM TableName
GROUP BY jobId, jobName

What is the best way to ensure only one instance of a Bash script is running?

first test example

[[ $(lsof -t $0| wc -l) > 1 ]] && echo "At least one of $0 is running"

second test example

currsh=$0
currpid=$$
runpid=$(lsof -t $currsh| paste -s -d " ")
if [[ $runpid == $currpid ]]
then
  sleep 11111111111111111
else
  echo -e "\nPID($runpid)($currpid) ::: At least one of \"$currsh\" is running !!!\n"
  false
  exit 1
fi

explanation

"lsof -t" to list all pids of current running scripts named "$0".

Command "lsof" will do two advantages.

  1. Ignore pids which is editing by editor such as vim, because vim edit its mapping file such as ".file.swp".
  2. Ignore pids forked by current running shell scripts, which most "grep" derivative command can't achieve it. Use "pstree -pH pidnum" command to see details about current process forking status.

surface plots in matplotlib

Just to chime in, Emanuel had the answer that I (and probably many others) are looking for. If you have 3d scattered data in 3 separate arrays, pandas is an incredible help and works much better than the other options. To elaborate, suppose your x,y,z are some arbitrary variables. In my case these were c,gamma, and errors because I was testing a support vector machine. There are many potential choices to plot the data:

  • scatter3D(cParams, gammas, avg_errors_array) - this works but is overly simplistic
  • plot_wireframe(cParams, gammas, avg_errors_array) - this works, but will look ugly if your data isn't sorted nicely, as is potentially the case with massive chunks of real scientific data
  • ax.plot3D(cParams, gammas, avg_errors_array) - similar to wireframe

Wireframe plot of the data

Wireframe plot of the data

3d scatter of the data

3d scatter of the data

The code looks like this:

    fig = plt.figure()
    ax = fig.gca(projection='3d')
    ax.set_xlabel('c parameter')
    ax.set_ylabel('gamma parameter')
    ax.set_zlabel('Error rate')
    #ax.plot_wireframe(cParams, gammas, avg_errors_array)
    #ax.plot3D(cParams, gammas, avg_errors_array)
    #ax.scatter3D(cParams, gammas, avg_errors_array, zdir='z',cmap='viridis')

    df = pd.DataFrame({'x': cParams, 'y': gammas, 'z': avg_errors_array})
    surf = ax.plot_trisurf(df.x, df.y, df.z, cmap=cm.jet, linewidth=0.1)
    fig.colorbar(surf, shrink=0.5, aspect=5)    
    plt.savefig('./plots/avgErrs_vs_C_andgamma_type_%s.png'%(k))
    plt.show()

Here is the final output:

plot_trisurf of xyz data

What is the (function() { } )() construct in JavaScript?

IIFE (Immediately invoked function expression) is a function which executes as soon as the script loads and goes away.

Consider the function below written in a file named iife.js

(function(){
       console.log("Hello Stackoverflow!");
   })();

This code above will execute as soon as you load iife.js and will print 'Hello Stackoverflow!' on the developer tools' console.

For a Detailed explanation see Immediately-Invoked Function Expression (IIFE)

How do you serve a file for download with AngularJS or Javascript?

Would just like to add that in case it doesn't download the file because of unsafe:blob:null... when you hover over the download button, you have to sanitize it. For instance,

var app = angular.module('app', []);

app.config(function($compileProvider){

$compileProvider.aHrefSanitizationWhitelist(/^\s*(|blob|):/);

Auto insert date and time in form input field?

$("#startDate").val($.datepicker.formatDate("dd/mm/yy", new Date()));
$("#endDate").val($.datepicker.formatDate("dd/mm/yy", new Date()));

Add the above code at the end of the script. This is required because the datepicker plugin has no provision to set the date in the control while initializing.

Get skin path in Magento?

First of all it is not recommended to have php files with functions in design folder. You should create a new module or extend (copy from core to local a helper and add function onto that class) and do not change files from app/code/core.

To answer to your question you can use:

require(Mage::getBaseDir('design').'/frontend/default/mytheme/myfunc.php');

Best practice (as a start) will be to create in /app/code/local/Mage/Core/Helper/Extra.php a php file:

<?php
class Mage_Core_Helper_Extra extends Mage_Core_Helper_Abstract
{

    public function getSomething()
    {
        return 'Someting';
    }

}

And to use it in phtml files use:

$this->helper('core/extra')->getSomething();

Or in all the places:

Mage::helper('core/extra')->getSomething();

What is the purpose of the : (colon) GNU Bash builtin?

It's similar to pass in Python.

One use would be to stub out a function until it gets written:

future_function () { :; }

Tomcat 8 throwing - org.apache.catalina.webresources.Cache.getResource Unable to add the resource

I had the same issue when upgrading from Tomcat 7 to 8: a continuous large flood of log warnings about cache.

1. Short Answer

Add this within the Context xml element of your $CATALINA_BASE/conf/context.xml:

<!-- The default value is 10240 kbytes, even when not added to context.xml.
So increase it high enough, until the problem disappears, for example set it to 
a value 5 times as high: 51200. -->
<Resources cacheMaxSize="51200" />

So the default is 10240 (10 mbyte), so set a size higher than this. Than tune for optimum settings where the warnings disappear. Note that the warnings may come back under higher traffic situations.

1.1 The cause (short explanation)

The problem is caused by Tomcat being unable to reach its target cache size due to cache entries that are less than the TTL of those entries. So Tomcat didn't have enough cache entries that it could expire, because they were too fresh, so it couldn't free enough cache and thus outputs warnings.

The problem didn't appear in Tomcat 7 because Tomcat 7 simply didn't output warnings in this situation. (Causing you and me to use poor cache settings without being notified.)

The problem appears when receiving a relative large amount of HTTP requests for resources (usually static) in a relative short time period compared to the size and TTL of the cache. If the cache is reaching its maximum (10mb by default) with more than 95% of its size with fresh cache entries (fresh means less than less than 5 seconds in cache), than you will get a warning message for each webResource that Tomcat tries to load in the cache.

1.2 Optional info

Use JMX if you need to tune cacheMaxSize on a running server without rebooting it.

The quickest fix would be to completely disable cache: <Resources cachingAllowed="false" />, but that's suboptimal, so increase cacheMaxSize as I just described.

2. Long Answer

2.1 Background information

A WebSource is a file or directory in a web application. For performance reasons, Tomcat can cache WebSources. The maximum of the static resource cache (all resources in total) is by default 10240 kbyte (10 mbyte). A webResource is loaded into the cache when the webResource is requested (for example when loading a static image), it's then called a cache entry. Every cache entry has a TTL (time to live), which is the time that the cache entry is allowed to stay in the cache. When the TTL expires, the cache entry is eligible to be removed from the cache. The default value of the cacheTTL is 5000 milliseconds (5 seconds).

There is more to tell about caching, but that is irrelevant for the problem.

2.2 The cause

The following code from the Cache class shows the caching policy in detail:

152  // Content will not be cached but we still need metadata size
153 long delta = cacheEntry.getSize();
154 size.addAndGet(delta);
156 if (size.get() > maxSize) {
157 // Process resources unordered for speed. Trades cache
158 // efficiency (younger entries may be evicted before older
159 // ones) for speed since this is on the critical path for
160 // request processing
161 long targetSize =
162 maxSize * (100 - TARGET_FREE_PERCENT_GET) / 100;
163 long newSize = evict(
164 targetSize, resourceCache.values().iterator());
165 if (newSize > maxSize) {
166 // Unable to create sufficient space for this resource
167 // Remove it from the cache
168 removeCacheEntry(path);
169 log.warn(sm.getString("cache.addFail", path));
170 }
171 }

When loading a webResource, the code calculates the new size of the cache. If the calculated size is larger than the default maximum size, than one or more cached entries have to be removed, otherwise the new size will exceed the maximum. So the code will calculate a "targetSize", which is the size the cache wants to stay under (as an optimum), which is by default 95% of the maximum. In order to reach this targetSize, entries have to be removed/evicted from the cache. This is done using the following code:

215  private long evict(long targetSize, Iterator<CachedResource> iter) {
217 long now = System.currentTimeMillis();
219 long newSize = size.get();
221 while (newSize > targetSize && iter.hasNext()) {
222 CachedResource resource = iter.next();
224 // Don't expire anything that has been checked within the TTL
225 if (resource.getNextCheck() > now) {
226 continue;
227 }
229 // Remove the entry from the cache
230 removeCacheEntry(resource.getWebappPath());
232 newSize = size.get();
233 }
235 return newSize;
236 }

So a cache entry is removed when its TTL is expired and the targetSize hasn't been reached yet.

After the attempt to free cache by evicting cache entries, the code will do:

165  if (newSize > maxSize) {
166 // Unable to create sufficient space for this resource
167 // Remove it from the cache
168 removeCacheEntry(path);
169 log.warn(sm.getString("cache.addFail", path));
170 }

So if after the attempt to free cache, the size still exceeds the maximum, it will show the warning message about being unable to free:

cache.addFail=Unable to add the resource at [{0}] to the cache for web application [{1}] because there was insufficient free space available after evicting expired cache entries - consider increasing the maximum size of the cache

2.3 The problem

So as the warning message says, the problem is

insufficient free space available after evicting expired cache entries - consider increasing the maximum size of the cache

If your web application loads a lot of uncached webResources (about maximum of cache, by default 10mb) within a short time (5 seconds), then you'll get the warning.

The confusing part is that Tomcat 7 didn't show the warning. This is simply caused by this Tomcat 7 code:

1606  // Add new entry to cache
1607 synchronized (cache) {
1608 // Check cache size, and remove elements if too big
1609 if ((cache.lookup(name) == null) && cache.allocate(entry.size)) {
1610 cache.load(entry);
1611 }
1612 }

combined with:

231  while (toFree > 0) {
232 if (attempts == maxAllocateIterations) {
233 // Give up, no changes are made to the current cache
234 return false;
235 }

So Tomcat 7 simply doesn't output any warning at all when it's unable to free cache, whereas Tomcat 8 will output a warning.

So if you are using Tomcat 8 with the same default caching configuration as Tomcat 7, and you got warnings in Tomcat 8, than your (and mine) caching settings of Tomcat 7 were performing poorly without warning.

2.4 Solutions

There are multiple solutions:

  1. Increase cache (recommended)
  2. Lower the TTL (not recommended)
  3. Suppress cache log warnings (not recommended)
  4. Disable cache

2.4.1. Increase cache (recommended)

As described here: http://tomcat.apache.org/tomcat-8.0-doc/config/resources.html

By adding <Resources cacheMaxSize="XXXXX" /> within the Context element in $CATALINA_BASE/conf/context.xml, where "XXXXX" stands for an increased cache size, specified in kbytes. The default is 10240 (10 mbyte), so set a size higher than this.

You'll have to tune for optimum settings. Note that the problem may come back when you suddenly have an increase in traffic/resource requests.

To avoid having to restart the server every time you want to try a new cache size, you can change it without restarting by using JMX.

To enable JMX, add this to $CATALINA_BASE/conf/server.xml within the Server element: <Listener className="org.apache.catalina.mbeans.JmxRemoteLifecycleListener" rmiRegistryPortPlatform="6767" rmiServerPortPlatform="6768" /> and download catalina-jmx-remote.jar from https://tomcat.apache.org/download-80.cgi and put it in $CATALINA_HOME/lib. Then use jConsole (shipped by default with the Java JDK) to connect over JMX to the server and look through the settings for settings to increase the cache size while the server is running. Changes in these settings should take affect immediately.

2.4.2. Lower the TTL (not recommended)

Lower the cacheTtl value by something lower than 5000 milliseconds and tune for optimal settings.

For example: <Resources cacheTtl="2000" />

This comes effectively down to having and filling a cache in ram without using it.

2.4.3. Suppress cache log warnings (not recommended)

Configure logging to disable the logger for org.apache.catalina.webresources.Cache.

For more info about logging in Tomcat: http://tomcat.apache.org/tomcat-8.0-doc/logging.html

2.4.4. Disable cache

You can disable the cache by setting cachingAllowed to false. <Resources cachingAllowed="false" />

Although I can remember that in a beta version of Tomcat 8, I was using JMX to disable the cache. (Not sure why exactly, but there may be a problem with disabling the cache via server.xml.)

post ajax data to PHP and return data

So what does count_votes look like? Is it a script? Anything that you want to get back from an ajax call can be retrieved using a simple echo (of course you could use JSON or xml, but for this simple example you would just need to output something in count_votes.php like:

$id = $_POST['id'];

function getVotes($id){
    // call your database here
    $query = ("SELECT votes FROM poll WHERE ID = $id");
    $result = @mysql_query($query);
    $row = mysql_fetch_row($result);

    return $row->votes;
}
$votes = getVotes($id);
echo $votes;

This is just pseudocode, but should give you the idea. What ever you echo from count_votes will be what is returned to "data" in your ajax call.

How to randomly select rows in SQL?

In order to shuffle the SQL result set, you need to use a database-specific function call.

Note that sorting a large result set using a RANDOM function might turn out to be very slow, so make sure you do that on small result sets.

If you have to shuffle a large result set and limit it afterward, then it's better to use something like the Oracle SAMPLE(N) or the TABLESAMPLE in SQL Server or PostgreSQL instead of a random function in the ORDER BY clause.

So, assuming we have the following database table:

Song database table

And the following rows in the song table:

| id | artist                          | title                              |
|----|---------------------------------|------------------------------------|
| 1  | Miyagi & ???????? ft. ??? ????? | I Got Love                         |
| 2  | HAIM                            | Don't Save Me (Cyril Hahn Remix)   |
| 3  | 2Pac ft. DMX                    | Rise Of A Champion (GalilHD Remix) |
| 4  | Ed Sheeran & Passenger          | No Diggity (Kygo Remix)            |
| 5  | JP Cooper ft. Mali-Koa          | All This Love                      |

Oracle

On Oracle, you need to use the DBMS_RANDOM.VALUE function, as illustrated by the following example:

SELECT
    artist||' - '||title AS song
FROM song
ORDER BY DBMS_RANDOM.VALUE

When running the aforementioned SQL query on Oracle, we are going to get the following result set:

| song                                              |
|---------------------------------------------------|
| JP Cooper ft. Mali-Koa - All This Love            |
| 2Pac ft. DMX - Rise Of A Champion (GalilHD Remix) |
| HAIM - Don't Save Me (Cyril Hahn Remix)           |
| Ed Sheeran & Passenger - No Diggity (Kygo Remix)  |
| Miyagi & ???????? ft. ??? ????? - I Got Love      |

Notice that the songs are being listed in random order, thanks to the DBMS_RANDOM.VALUE function call used by the ORDER BY clause.

SQL Server

On SQL Server, you need to use the NEWID function, as illustrated by the following example:

SELECT
    CONCAT(CONCAT(artist, ' - '), title) AS song
FROM song
ORDER BY NEWID()

When running the aforementioned SQL query on SQL Server, we are going to get the following result set:

| song                                              |
|---------------------------------------------------|
| Miyagi & ???????? ft. ??? ????? - I Got Love      |
| JP Cooper ft. Mali-Koa - All This Love            |
| HAIM - Don't Save Me (Cyril Hahn Remix)           |
| Ed Sheeran & Passenger - No Diggity (Kygo Remix)  |
| 2Pac ft. DMX - Rise Of A Champion (GalilHD Remix) |

Notice that the songs are being listed in random order, thanks to the NEWID function call used by the ORDER BY clause.

PostgreSQL

On PostgreSQL, you need to use the random function, as illustrated by the following example:

SELECT
    artist||' - '||title AS song
FROM song
ORDER BY random()

When running the aforementioned SQL query on PostgreSQL, we are going to get the following result set:

| song                                              |
|---------------------------------------------------|
| 2Pac ft. DMX - Rise Of A Champion (GalilHD Remix) |
| JP Cooper ft. Mali-Koa - All This Love            |
| Ed Sheeran & Passenger - No Diggity (Kygo Remix)  |
| HAIM - Don't Save Me (Cyril Hahn Remix)           |
| Miyagi & ???????? ft. ??? ????? - I Got Love      |

Notice that the songs are being listed in random order, thanks to the random function call used by the ORDER BY clause.

MySQL

On MySQL, you need to use the RAND function, as illustrated by the following example:

SELECT
  CONCAT(CONCAT(artist, ' - '), title) AS song
FROM song
ORDER BY RAND()

When running the aforementioned SQL query on MySQL, we are going to get the following result set:

| song                                              |
|---------------------------------------------------|
| HAIM - Don't Save Me (Cyril Hahn Remix)           |
| Ed Sheeran & Passenger - No Diggity (Kygo Remix)  |
| Miyagi & ???????? ft. ??? ????? - I Got Love      |
| 2Pac ft. DMX - Rise Of A Champion (GalilHD Remix) |
| JP Cooper ft. Mali-Koa - All This Love            |

Notice that the songs are being listed in random order, thanks to the RAND function call used by the ORDER BY clause.

Java - Writing strings to a CSV file

I see you already have a answer but here is another answer, maybe even faster A simple class to pass in a List of objects and retrieve either a csv or excel or password protected zip csv or excel. https://github.com/ernst223/spread-sheet-exporter

SpreadSheetExporter spreadSheetExporter = new SpreadSheetExporter(List<Object>, "Filename");
File fileCSV = spreadSheetExporter.getCSV();

Conversion failed when converting date and/or time from character string while inserting datetime

There are many formats supported by SQL Server - see the MSDN Books Online on CAST and CONVERT. Most of those formats are dependent on what settings you have - therefore, these settings might work some times - and sometimes not.

The way to solve this is to use the (slightly adapted) ISO-8601 date format that is supported by SQL Server - this format works always - regardless of your SQL Server language and dateformat settings.

The ISO-8601 format is supported by SQL Server comes in two flavors:

  • YYYYMMDD for just dates (no time portion); note here: no dashes!, that's very important! YYYY-MM-DD is NOT independent of the dateformat settings in your SQL Server and will NOT work in all situations!

or:

  • YYYY-MM-DDTHH:MM:SS for dates and times - note here: this format has dashes (but they can be omitted), and a fixed T as delimiter between the date and time portion of your DATETIME.

This is valid for SQL Server 2000 and newer.

So in your concrete case - use these strings:

insert into table1 values('2012-02-21T18:10:00', '2012-01-01T00:00:00');

and you should be fine (note: you need to use the international 24-hour format rather than 12-hour AM/PM format for this).

Alternatively: if you're on SQL Server 2008 or newer, you could also use the DATETIME2 datatype (instead of plain DATETIME) and your current INSERT would just work without any problems! :-) DATETIME2 is a lot better and a lot less picky on conversions - and it's the recommend date/time data types for SQL Server 2008 or newer anyway.

SELECT
   CAST('02-21-2012 6:10:00 PM' AS DATETIME2),     -- works just fine
   CAST('01-01-2012 12:00:00 AM' AS DATETIME2)   -- works just fine  

Don't ask me why this whole topic is so tricky and somewhat confusing - that's just the way it is. But with the YYYYMMDD format, you should be fine for any version of SQL Server and for any language and dateformat setting in your SQL Server.

javac not working in windows command prompt

I faced the exact same problem that java would work but javac would not on a cmd prompt in Windows 8.

The problem occured because I forgot to remove '>' at the end of the path name, i.e., it was like this:

C:\Program Files\Java\jdk*\bin>

where it was suppose to be like this:

C:\Program Files\Java\jdk*\bin

*.h or *.hpp for your class definitions

I prefer .hpp for C++ to make it clear to both editors and to other programmers that it is a C++ header rather than a C header file.

Clearing an HTML file upload field via JavaScript

try this its work fine

document.getElementById('fileUpload').parentNode.innerHTML = document.getElementById('fileUpload').parentNode.innerHTML;

How to align two divs side by side using the float, clear, and overflow elements with a fixed position div/

I did this:

<!DOCTYPE HTML>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>AutoDealer</title>
        <style>
        .container{
            width: 860px;
            height: 1074px;
            margin-right: auto;
            margin-left: auto;
            border: 1px solid red;

        }
        .nav{

        }
        .wrapper{
            display: block;
            overflow: hidden;
            border: 1px solid green;
        }
       .otherWrapper{
            display: block;
            overflow: hidden;
            border: 1px solid green;
            float:left;
        }
    .left{
        width: 399px;
        float: left;
        background-color: pink;
    }
            .bottom{
        clear: both;
        width: 399px;
        background-color: yellow;



    }
    .right{
        height:350px;
        width: 449px;
        overflow: hidden;
        background-color: blue;
        overflow: hidden;
        float:right;
    }

    </style>
</head>
<body>
    <div class="container">
        <div class="nav"></div>
        <div class="wrapper">
        <div class="otherWrapper">
            <div class="left">
                <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum ultricies aliquet tellus sit amet ultrices. Sed faucibus, nunc vitae accumsan laoreet, enim metus varius nulla, ac ultricies felis ante venenatis justo. In hac habitasse platea dictumst. In cursus enim nec urna molestie, id mattis elit mollis. In sed eros eget nibh congue vehicula. Nunc vestibulum enim risus, sit amet suscipit dui auctor et. Morbi orci magna, accumsan at turpis a, scelerisque congue eros. Morbi non mi vel nibh varius blandit sed et urna.</p>
            </div>
             <div class="bottom">
                <p>ucibus eros, sed viverra ex. Vestibulum aliquet accumsan massa, at feugiat ipsum interdum blandit. Morbi et orci hendrerit orci consequat ornare ac et sapien. Nulla vestibulum lectus bibendum, efficitur purus in, venenatis nunc. Nunc tincidunt velit sit amet orci pellentesq</p></div>
             </div>

             <div class="right">
                <p>Quisque vulputate mi id turpis luctus, quis laoreet nisi vestibulum. Morbi facilisis erat vitae augue ornare convallis. Fusce sit amet magna rutrum, hendrerit purus vitae, congue justo. Nam non mi eget purus ultricies lacinia. Fusce ante nisl, efficitur venenatis urna ut, pellentesque egestas nisl. In ut faucibus eros, sed viverra ex. Vestibulum aliquet accumsan massa, at feugiat ipsum interdum blandit. Morbi et orci hendrerit orci consequat ornare ac et sapien. Nulla vestibulum lectus bibendum, efficitur purus in, venenatis nunc. Nunc tincidunt velit sit amet orci pellentesque maximus. Quisque a tempus lectus.</p>
             </div>
        </div>
    </div>
</body>

So basically I just made another div to wrap the pink and yellow, and I make that div have a float:left on it. The blue div has a float:right on it.

Getting a browser's name client-side

This code will return "browser" and "browserVersion"
Works on 95% of 80+ browsers

var geckobrowsers;
var browser = "";
var browserVersion = 0;
var agent = navigator.userAgent + " ";
if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "5.0" && agent.indexOf("like Gecko") != -1){
    geckobrowsers = agent.substring(agent.indexOf("like Gecko")+10).substring(agent.substring(agent.indexOf("like Gecko")+10).indexOf(") ")+2).replace("LG Browser", "LGBrowser").replace("360SE", "360SE/");
    for(i = 0; i < 1; i++){
        geckobrowsers = geckobrowsers.replace(geckobrowsers.substring(geckobrowsers.indexOf("("), geckobrowsers.indexOf(")")+1), "");
    }
    geckobrowsers = geckobrowsers.split(" ");
    for(i = 0; i < geckobrowsers.length; i++){
        if(geckobrowsers[i].indexOf("/") == -1)geckobrowsers[i] = "Chrome";
        if(geckobrowsers[i].indexOf("/") != -1)geckobrowsers[i] = geckobrowsers[i].substring(0, geckobrowsers[i].indexOf("/"));
    }
    if(geckobrowsers.length < 4){
        browser = geckobrowsers[0];
    } else {
        for(i = 0; i < geckobrowsers.length; i++){
            if(geckobrowsers[i].indexOf("Chrome") == -1 && geckobrowsers[i].indexOf("Safari") == -1 && geckobrowsers[i].indexOf("Mobile") == -1 && geckobrowsers[i].indexOf("Version") == -1)browser = geckobrowsers[i];
        }
    }
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "5.0" && agent.indexOf("Gecko/") != -1){
    browser = agent.substring(agent.substring(agent.indexOf("Gecko/")+6).indexOf(" ") + agent.indexOf("Gecko/")+6).substring(0, agent.substring(agent.substring(agent.indexOf("Gecko/")+6).indexOf(" ") + agent.indexOf("Gecko/")+6).indexOf("/"));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "5.0" && agent.indexOf("Clecko/") != -1){
    browser = agent.substring(agent.substring(agent.indexOf("Clecko/")+7).indexOf(" ") + agent.indexOf("Clecko/")+7).substring(0, agent.substring(agent.substring(agent.indexOf("Clecko/")+7).indexOf(" ") + agent.indexOf("Clecko/")+7).indexOf("/"));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "5.0"){
    browser = agent.substring(agent.indexOf("(")+1, agent.indexOf(";"));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "4.0" && agent.indexOf(")")+1 == agent.length-1){
    browser = agent.substring(agent.indexOf("(")+1, agent.indexOf(")")).split("; ")[agent.substring(agent.indexOf("(")+1, agent.indexOf(")")).split("; ").length-1];
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "4.0" && agent.indexOf(")")+1 != agent.length-1){
    if(agent.substring(agent.indexOf(") ")+2).indexOf("/") != -1)browser = agent.substring(agent.indexOf(") ")+2, agent.indexOf(") ")+2+agent.substring(agent.indexOf(") ")+2).indexOf("/"));
    if(agent.substring(agent.indexOf(") ")+2).indexOf("/") == -1)browser = agent.substring(agent.indexOf(") ")+2, agent.indexOf(") ")+2+agent.substring(agent.indexOf(") ")+2).indexOf(" "));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(0, 6) == "Opera/"){
    browser = "Opera";
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
    if(agent.substring(agent.indexOf("(")+1).indexOf(";") != -1)os = agent.substring(agent.indexOf("(")+1, agent.indexOf("(")+1+agent.substring(agent.indexOf("(")+1).indexOf(";"));
    if(agent.substring(agent.indexOf("(")+1).indexOf(";") == -1)os = agent.substring(agent.indexOf("(")+1, agent.indexOf("(")+1+agent.substring(agent.indexOf("(")+1).indexOf(")"));
} else if(agent.substring(0, agent.indexOf("/")) != "Mozilla" && agent.substring(0, agent.indexOf("/")) != "Opera"){
    browser = agent.substring(0, agent.indexOf("/"));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else {
    browser = agent;
}
alert(browser + " v" + browserVersion);

Most common C# bitwise operations on enums

This was inspired by using Sets as indexers in Delphi, way back when:

/// Example of using a Boolean indexed property
/// to manipulate a [Flags] enum:

public class BindingFlagsIndexer
{
  BindingFlags flags = BindingFlags.Default;

  public BindingFlagsIndexer()
  {
  }

  public BindingFlagsIndexer( BindingFlags value )
  {
     this.flags = value;
  }

  public bool this[BindingFlags index]
  {
    get
    {
      return (this.flags & index) == index;
    }
    set( bool value )
    {
      if( value )
        this.flags |= index;
      else
        this.flags &= ~index;
    }
  }

  public BindingFlags Value 
  {
    get
    { 
      return flags;
    } 
    set( BindingFlags value ) 
    {
      this.flags = value;
    }
  }

  public static implicit operator BindingFlags( BindingFlagsIndexer src )
  {
     return src != null ? src.Value : BindingFlags.Default;
  }

  public static implicit operator BindingFlagsIndexer( BindingFlags src )
  {
     return new BindingFlagsIndexer( src );
  }

}

public static class Class1
{
  public static void Example()
  {
    BindingFlagsIndexer myFlags = new BindingFlagsIndexer();

    // Sets the flag(s) passed as the indexer:

    myFlags[BindingFlags.ExactBinding] = true;

    // Indexer can specify multiple flags at once:

    myFlags[BindingFlags.Instance | BindingFlags.Static] = true;

    // Get boolean indicating if specified flag(s) are set:

    bool flatten = myFlags[BindingFlags.FlattenHierarchy];

    // use | to test if multiple flags are set:

    bool isProtected = ! myFlags[BindingFlags.Public | BindingFlags.NonPublic];

  }
}

Nested rows with bootstrap grid system?

Bootstrap Version 3.x

As always, read Bootstrap's great documentation:

3.x Docs: https://getbootstrap.com/docs/3.3/css/#grid-nesting

Make sure the parent level row is inside of a .container element. Whenever you'd like to nest rows, just open up a new .row inside of your column.

Here's a simple layout to work from:

<div class="container">
    <div class="row">
        <div class="col-xs-6">
            <div class="big-box">image</div>
        </div>
        <div class="col-xs-6">
            <div class="row">
                <div class="col-xs-6"><div class="mini-box">1</div></div>
                <div class="col-xs-6"><div class="mini-box">2</div></div>
                <div class="col-xs-6"><div class="mini-box">3</div></div>
                <div class="col-xs-6"><div class="mini-box">4</div></div>
            </div>
        </div>
    </div>
</div>

Bootstrap Version 4.0

4.0 Docs: http://getbootstrap.com/docs/4.0/layout/grid/#nesting

Here's an updated version for 4.0, but you should really read the entire docs section on the grid so you understand how to leverage this powerful feature

<div class="container">
  <div class="row">
    <div class="col big-box">
      image
    </div>

    <div class="col">
      <div class="row">
        <div class="col mini-box">1</div>
        <div class="col mini-box">2</div>
      </div>
      <div class="row">
        <div class="col mini-box">3</div>
        <div class="col mini-box">4</div>
      </div>
    </div>

  </div>
</div>

Demo in Fiddle jsFiddle 3.x | jsFiddle 4.0

Which will look like this (with a little bit of added styling):

screenshot

How can I disable notices and warnings in PHP within the .htaccess file?

If you are in a shared hosting plan that doesn't have PHP installed as a module you will get a 500 server error when adding those flags to the .htaccess file.

But you can add the line

ini_set('display_errors','off');

on top of your .php file and it should work without any errors.

Plotting lines connecting points

Use the matplotlib.arrow() function and set the parameters head_length and head_width to zero to don't get an "arrow-end". The connections between the different points can be simply calculated using vector addition with: A = [1,2], B=[3,4] --> Connection between A and B is B-A = [2,2]. Drawing this vector starting at the tip of A ends at the tip of B.

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import style
style.use('fivethirtyeight')


A = np.array([[10,8],[1,2],[7,5],[3,5],[7,6],[8,7],[9,9],[4,5],[6,5],[6,8]])


fig = plt.figure(figsize=(10,10))
ax0 = fig.add_subplot(212)

ax0.scatter(A[:,0],A[:,1])


ax0.arrow(A[0][0],A[0][1],A[1][0]-A[0][0],A[1][1]-A[0][1],width=0.02,color='red',head_length=0.0,head_width=0.0)
ax0.arrow(A[2][0],A[2][1],A[9][0]-A[2][0],A[9][1]-A[2][1],width=0.02,color='red',head_length=0.0,head_width=0.0)
ax0.arrow(A[4][0],A[4][1],A[6][0]-A[4][0],A[6][1]-A[4][1],width=0.02,color='red',head_length=0.0,head_width=0.0)


plt.show()

enter image description here

pass parameter by link_to ruby on rails

Try:

<%= link_to "Add to cart", {:controller => "car", :action => "add_to_cart", :car => car.id }%>

and then in your controller

@car = Car.find(params[:car])

which, will find in your 'cars' table (as with rails pluralization) in your DB a car with id == to car.id

hope it helps! happy coding

more than a year later, but if you see it or anyone does, i could use the points ;D

How do I get the total number of unique pairs of a set in the database?

What you're looking for is n choose k. Basically:

enter image description here

For every pair of 100 items, you'd have 4,950 combinations - provided order doesn't matter (AB and BA are considered a single combination) and you don't want to repeat (AA is not a valid pair).

Python, remove all non-alphabet chars from string

Try:

s = ''.join(filter(str.isalnum, s))

This will take every char from the string, keep only alphanumeric ones and build a string back from them.

PostgreSQL return result set as JSON array?

TL;DR

SELECT json_agg(t) FROM t

for a JSON array of objects, and

SELECT
    json_build_object(
        'a', json_agg(t.a),
        'b', json_agg(t.b)
    )
FROM t

for a JSON object of arrays.

List of objects

This section describes how to generate a JSON array of objects, with each row being converted to a single object. The result looks like this:

[{"a":1,"b":"value1"},{"a":2,"b":"value2"},{"a":3,"b":"value3"}]

9.3 and up

The json_agg function produces this result out of the box. It automatically figures out how to convert its input into JSON and aggregates it into an array.

SELECT json_agg(t) FROM t

There is no jsonb (introduced in 9.4) version of json_agg. You can either aggregate the rows into an array and then convert them:

SELECT to_jsonb(array_agg(t)) FROM t

or combine json_agg with a cast:

SELECT json_agg(t)::jsonb FROM t

My testing suggests that aggregating them into an array first is a little faster. I suspect that this is because the cast has to parse the entire JSON result.

9.2

9.2 does not have the json_agg or to_json functions, so you need to use the older array_to_json:

SELECT array_to_json(array_agg(t)) FROM t

You can optionally include a row_to_json call in the query:

SELECT array_to_json(array_agg(row_to_json(t))) FROM t

This converts each row to a JSON object, aggregates the JSON objects as an array, and then converts the array to a JSON array.

I wasn't able to discern any significant performance difference between the two.

Object of lists

This section describes how to generate a JSON object, with each key being a column in the table and each value being an array of the values of the column. It's the result that looks like this:

{"a":[1,2,3], "b":["value1","value2","value3"]}

9.5 and up

We can leverage the json_build_object function:

SELECT
    json_build_object(
        'a', json_agg(t.a),
        'b', json_agg(t.b)
    )
FROM t

You can also aggregate the columns, creating a single row, and then convert that into an object:

SELECT to_json(r)
FROM (
    SELECT
        json_agg(t.a) AS a,
        json_agg(t.b) AS b
    FROM t
) r

Note that aliasing the arrays is absolutely required to ensure that the object has the desired names.

Which one is clearer is a matter of opinion. If using the json_build_object function, I highly recommend putting one key/value pair on a line to improve readability.

You could also use array_agg in place of json_agg, but my testing indicates that json_agg is slightly faster.

There is no jsonb version of the json_build_object function. You can aggregate into a single row and convert:

SELECT to_jsonb(r)
FROM (
    SELECT
        array_agg(t.a) AS a,
        array_agg(t.b) AS b
    FROM t
) r

Unlike the other queries for this kind of result, array_agg seems to be a little faster when using to_jsonb. I suspect this is due to overhead parsing and validating the JSON result of json_agg.

Or you can use an explicit cast:

SELECT
    json_build_object(
        'a', json_agg(t.a),
        'b', json_agg(t.b)
    )::jsonb
FROM t

The to_jsonb version allows you to avoid the cast and is faster, according to my testing; again, I suspect this is due to overhead of parsing and validating the result.

9.4 and 9.3

The json_build_object function was new to 9.5, so you have to aggregate and convert to an object in previous versions:

SELECT to_json(r)
FROM (
    SELECT
        json_agg(t.a) AS a,
        json_agg(t.b) AS b
    FROM t
) r

or

SELECT to_jsonb(r)
FROM (
    SELECT
        array_agg(t.a) AS a,
        array_agg(t.b) AS b
    FROM t
) r

depending on whether you want json or jsonb.

(9.3 does not have jsonb.)

9.2

In 9.2, not even to_json exists. You must use row_to_json:

SELECT row_to_json(r)
FROM (
    SELECT
        array_agg(t.a) AS a,
        array_agg(t.b) AS b
    FROM t
) r

Documentation

Find the documentation for the JSON functions in JSON functions.

json_agg is on the aggregate functions page.

Design

If performance is important, ensure you benchmark your queries against your own schema and data, rather than trust my testing.

Whether it's a good design or not really depends on your specific application. In terms of maintainability, I don't see any particular problem. It simplifies your app code and means there's less to maintain in that portion of the app. If PG can give you exactly the result you need out of the box, the only reason I can think of to not use it would be performance considerations. Don't reinvent the wheel and all.

Nulls

Aggregate functions typically give back NULL when they operate over zero rows. If this is a possibility, you might want to use COALESCE to avoid them. A couple of examples:

SELECT COALESCE(json_agg(t), '[]'::json) FROM t

Or

SELECT to_jsonb(COALESCE(array_agg(t), ARRAY[]::t[])) FROM t

Credit to Hannes Landeholm for pointing this out

In a javascript array, how do I get the last 5 elements, excluding the first element?

You can call:

arr.slice(Math.max(arr.length - 5, 1))

If you don't want to exclude the first element, use

arr.slice(Math.max(arr.length - 5, 0))

"React.Children.only expected to receive a single React element child" error when putting <Image> and <TouchableHighlight> in a <View>

just after TouchableWithoutFeedback or <TouchableHighlight> insert a <View> this way you won't get this error. why is that then @Pedram answer or other answers explains enough.

How does += (plus equal) work?

That is just a short form for:

sum = sum + value;

What is the significance of load factor in HashMap?

Default initial capacity of the HashMap takes is 16 and load factor is 0.75f (i.e 75% of current map size). The load factor represents at what level the HashMap capacity should be doubled.

For example product of capacity and load factor as 16 * 0.75 = 12. This represents that after storing the 12th key – value pair into the HashMap , its capacity becomes 32.

How do I create a slug in Django?

There is corner case with some utf-8 characters

Example:

>>> from django.template.defaultfilters import slugify
>>> slugify(u"test aescóln")
u'test-aescon' # there is no "l"

This can be solved with Unidecode

>>> from unidecode import unidecode
>>> from django.template.defaultfilters import slugify
>>> slugify(unidecode(u"test aescóln"))
u'test-aescoln'

Hashmap holding different data types as values for instance Integer, String and Object

If you don't have Your own Data Class, then you can design your map as follows

Map<Integer, Object> map=new HashMap<Integer, Object>();

Here don't forget to use "instanceof" operator while retrieving the values from MAP.

If you have your own Data class then then you can design your map as follows

Map<Integer, YourClassName> map=new HashMap<Integer, YourClassName>();

import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;


public class HashMapTest {
public static void main(String[] args) {
    Map<Integer,Demo> map=new HashMap<Integer, Demo>();
    Demo d1= new Demo(1,"hi",new Date(),1,1);
    Demo d2= new Demo(2,"this",new Date(),2,1);
    Demo d3= new Demo(3,"is",new Date(),3,1);
    Demo d4= new Demo(4,"mytest",new Date(),4,1);
    //adding values to map
    map.put(d1.getKey(), d1);
    map.put(d2.getKey(), d2);
    map.put(d3.getKey(), d3);
    map.put(d4.getKey(), d4);
    //retrieving values from map
    Set<Integer> keySet= map.keySet();
    for(int i:keySet){
        System.out.println(map.get(i));
    }
    //searching key on map
    System.out.println(map.containsKey(d1.getKey()));
    //searching value on map
    System.out.println(map.containsValue(d1));
}

}
class Demo{
    private int key;
    private String message;
    private Date time;
    private int count;
    private int version;

    public Demo(int key,String message, Date time, int count, int version){
        this.key=key;
        this.message = message;
        this.time = time;
        this.count = count;
        this.version = version;
    }
    public String getMessage() {
        return message;
    }
    public Date getTime() {
        return time;
    }
    public int getCount() {
        return count;
    }
    public int getVersion() {
        return version;
    }
    public int getKey() {
        return key;
    }
    @Override
    public String toString() {
        return "Demo [message=" + message + ", time=" + time
                + ", count=" + count + ", version=" + version + "]";
    }

}

What does the star operator mean, in a function call?

One small point: these are not operators. Operators are used in expressions to create new values from existing values (1+2 becomes 3, for example. The * and ** here are part of the syntax of function declarations and calls.

How do you get the selected value of a Spinner?

To get just the string value within the spinner use the following:

spinner.getSelectedItem().toString();

java.lang.NoClassDefFoundError in junit

Try below steps:

  1. Go to your project's run configuration. In Classpath tab add JUnit library.
  2. Retry the same steps.

It worked for me.

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

You don't need to use arrays.

JSON values can be arrays, objects, or primitives (numbers or strings).

You can write JSON like this:

{ 
    "stuff": {
        "onetype": [
            {"id":1,"name":"John Doe"},
            {"id":2,"name":"Don Joeh"}
        ],
        "othertype": {"id":2,"company":"ACME"}
    }, 
    "otherstuff": {
        "thing": [[1,42],[2,2]]
     }
}

You can use it like this:

obj.stuff.onetype[0].id
obj.stuff.othertype.id
obj.otherstuff.thing[0][1]  //thing is a nested array or a 2-by-2 matrix.
                            //I'm not sure whether you intended to do that.

How do I create a GUI for a windows application using C++?

If you want to learn about win32, WTL http://wtl.sourceforge.net/ is the pretty lightweight equivalent to MFC, but you have to love template to use it.

If you want something simple MFC is already integrated with VS, also it has a large base of extra code and workarounds of know bugs in the net already.

Also Qt is really great framework it have a nice set of tools, dialog editor, themes, and a lot of other stuff, plus your application will be ready to be cross platform, although it will require some time to get accustomed.

You also have Gtk, wxWindow, and you will have no problems if you have already used it on linux.

How to sort an array based on the length of each element?

If you want to preserve the order of the element with the same length as the original array, use bubble sort.

Input = ["ab","cdc","abcd","de"];

Output  = ["ab","cd","cdc","abcd"]

Function:

function bubbleSort(strArray){
  const arrayLength = Object.keys(strArray).length;
    var swapp;
    var newLen = arrayLength-1;
    var sortedStrArrByLenght=strArray;
    do {
        swapp = false;
        for (var i=0; i < newLen; i++)
        {
            if (sortedStrArrByLenght[i].length > sortedStrArrByLenght[i+1].length)
            {
               var temp = sortedStrArrByLenght[i];
               sortedStrArrByLenght[i] = sortedStrArrByLenght[i+1];
               sortedStrArrByLenght[i+1] = temp;
               swapp = true;
            }
        }
        newLen--;
    } while (swap);
  return sortedStrArrByLenght;
}

400 BAD request HTTP error code meaning?

A 400 means that the request was malformed. In other words, the data stream sent by the client to the server didn't follow the rules.

In the case of a REST API with a JSON payload, 400's are typically, and correctly I would say, used to indicate that the JSON is invalid in some way according to the API specification for the service.

By that logic, both the scenarios you provided should be 400s.

Imagine instead this were XML rather than JSON. In both cases, the XML would never pass schema validation--either because of an undefined element or an improper element value. That would be a bad request. Same deal here.

How to declare a variable in a PostgreSQL query

I accomplished the same goal by using a WITH clause, it's nowhere near as elegant but can do the same thing. Though for this example it's really overkill. I also don't particularly recommend this.

WITH myconstants (var1, var2) as (
   values (5, 'foo')
)
SELECT *
FROM somewhere, myconstants
WHERE something = var1
   OR something_else = var2;

jQuery hover and class selector

I just coded up an example in jQuery on how to create div overlays over radio buttons to create a compact, interactive but simple color selector plug-in for jQuery

http://blarnee.com/wp/jquery-colour-selector-plug-in-with-support-for-graceful-degradation/

How do I make XAML DataGridColumns fill the entire DataGrid?

My 2 Cent ->

Very late to party

DataGrid -> Column -> Width="*" only work if DataGrid parent container has fix width.

example : i put the DataGrid in Grid -> Column whose width="Auto" then Width="*" in DataGrid does not work but if you set Grid -> Column Width="450" mean fixed then it work fine

Use SELECT inside an UPDATE query

I wrote about some of the limitations of correlated subqueries in Access/JET SQL a while back, and noted the syntax for joining multiple tables for SQL UPDATEs. Based on that info and some quick testing, I don't believe there's any way to do what you want with Access/JET in a single SQL UPDATE statement. If you could, the statement would read something like this:

UPDATE FUNCTIONS A
INNER JOIN (
  SELECT AA.Func_ID, Min(BB.Tax_Code) AS MinOfTax_Code
  FROM TAX BB, FUNCTIONS AA
  WHERE AA.Func_Pure<=BB.Tax_ToPrice AND AA.Func_Year= BB.Tax_Year
  GROUP BY AA.Func_ID
) B 
ON B.Func_ID = A.Func_ID
SET A.Func_TaxRef = B.MinOfTax_Code

Alternatively, Access/JET will sometimes let you get away with saving a subquery as a separate query and then joining it in the UPDATE statement in a more traditional way. So, for instance, if we saved the SELECT subquery above as a separate query named FUNCTIONS_TAX, then the UPDATE statement would be:

UPDATE FUNCTIONS
INNER JOIN FUNCTIONS_TAX
ON FUNCTIONS.Func_ID = FUNCTIONS_TAX.Func_ID
SET FUNCTIONS.Func_TaxRef = FUNCTIONS_TAX.MinOfTax_Code

However, this still doesn't work.

I believe the only way you will make this work is to move the selection and aggregation of the minimum Tax_Code value out-of-band. You could do this with a VBA function, or more easily using the Access DLookup function. Save the GROUP BY subquery above to a separate query named FUNCTIONS_TAX and rewrite the UPDATE statement as:

UPDATE FUNCTIONS
SET Func_TaxRef = DLookup(
  "MinOfTax_Code", 
  "FUNCTIONS_TAX", 
  "Func_ID = '" & Func_ID & "'"
)

Note that the DLookup function prevents this query from being used outside of Access, for instance via JET OLEDB. Also, the performance of this approach can be pretty terrible depending on how many rows you're targeting, as the subquery is being executed for each FUNCTIONS row (because, of course, it is no longer correlated, which is the whole point in order for it to work).

Good luck!

How can I use Python to get the system hostname?

You have to execute this line of code

sock_name = socket.gethostname()

And then you can use the name to find the addr :

print(socket.gethostbyname(sock_name))

Explicit Return Type of Lambda

The return type of a lambda (in C++11) can be deduced, but only when there is exactly one statement, and that statement is a return statement that returns an expression (an initializer list is not an expression, for example). If you have a multi-statement lambda, then the return type is assumed to be void.

Therefore, you should do this:

  remove_if(rawLines.begin(), rawLines.end(), [&expression, &start, &end, &what, &flags](const string& line) -> bool
  {
    start = line.begin();
    end = line.end();
    bool temp = boost::regex_search(start, end, what, expression, flags);
    return temp;
  })

But really, your second expression is a lot more readable.

How to get SLF4J "Hello World" working with log4j?

you need to add 3 dependency ( API+ API implementation + log4j dependency) 
Add also this 
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.5</version>
</dependency>

# And to see log in command line , set log4j.properties 

# Root logger option
log4j.rootLogger=INFO, file, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

#And to see log in file  , set log4j.properties 
# Direct log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=./logs/logging.log
log4j.appender.file.MaxFileSize=10MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

Table column sizing

I hacked this out for release Bootstrap 4.1.1 per my needs before I saw @florian_korner's post. Looks very similar.

If you use sass you can paste this snippet at the end of your bootstrap includes. It seems to fix the issue for chrome, IE, and edge. Does not seem to break anything in firefox.

@mixin make-td-col($size, $columns: $grid-columns) {
    width: percentage($size / $columns);
}

@each $breakpoint in map-keys($grid-breakpoints) {
    $infix: breakpoint-infix($breakpoint, $grid-breakpoints);

    @for $i from 1 through $grid-columns {
        td.col#{$infix}-#{$i}, th.col#{$infix}-#{$i} {
            @include make-td-col($i, $grid-columns);
        }
    }
}

or if you just want the compiled css utility:

td.col-1, th.col-1 {
  width: 8.33333%; }

td.col-2, th.col-2 {
  width: 16.66667%; }

td.col-3, th.col-3 {
  width: 25%; }

td.col-4, th.col-4 {
  width: 33.33333%; }

td.col-5, th.col-5 {
  width: 41.66667%; }

td.col-6, th.col-6 {
  width: 50%; }

td.col-7, th.col-7 {
  width: 58.33333%; }

td.col-8, th.col-8 {
  width: 66.66667%; }

td.col-9, th.col-9 {
  width: 75%; }

td.col-10, th.col-10 {
  width: 83.33333%; }

td.col-11, th.col-11 {
  width: 91.66667%; }

td.col-12, th.col-12 {
  width: 100%; }

td.col-sm-1, th.col-sm-1 {
  width: 8.33333%; }

td.col-sm-2, th.col-sm-2 {
  width: 16.66667%; }

td.col-sm-3, th.col-sm-3 {
  width: 25%; }

td.col-sm-4, th.col-sm-4 {
  width: 33.33333%; }

td.col-sm-5, th.col-sm-5 {
  width: 41.66667%; }

td.col-sm-6, th.col-sm-6 {
  width: 50%; }

td.col-sm-7, th.col-sm-7 {
  width: 58.33333%; }

td.col-sm-8, th.col-sm-8 {
  width: 66.66667%; }

td.col-sm-9, th.col-sm-9 {
  width: 75%; }

td.col-sm-10, th.col-sm-10 {
  width: 83.33333%; }

td.col-sm-11, th.col-sm-11 {
  width: 91.66667%; }

td.col-sm-12, th.col-sm-12 {
  width: 100%; }

td.col-md-1, th.col-md-1 {
  width: 8.33333%; }

td.col-md-2, th.col-md-2 {
  width: 16.66667%; }

td.col-md-3, th.col-md-3 {
  width: 25%; }

td.col-md-4, th.col-md-4 {
  width: 33.33333%; }

td.col-md-5, th.col-md-5 {
  width: 41.66667%; }

td.col-md-6, th.col-md-6 {
  width: 50%; }

td.col-md-7, th.col-md-7 {
  width: 58.33333%; }

td.col-md-8, th.col-md-8 {
  width: 66.66667%; }

td.col-md-9, th.col-md-9 {
  width: 75%; }

td.col-md-10, th.col-md-10 {
  width: 83.33333%; }

td.col-md-11, th.col-md-11 {
  width: 91.66667%; }

td.col-md-12, th.col-md-12 {
  width: 100%; }

td.col-lg-1, th.col-lg-1 {
  width: 8.33333%; }

td.col-lg-2, th.col-lg-2 {
  width: 16.66667%; }

td.col-lg-3, th.col-lg-3 {
  width: 25%; }

td.col-lg-4, th.col-lg-4 {
  width: 33.33333%; }

td.col-lg-5, th.col-lg-5 {
  width: 41.66667%; }

td.col-lg-6, th.col-lg-6 {
  width: 50%; }

td.col-lg-7, th.col-lg-7 {
  width: 58.33333%; }

td.col-lg-8, th.col-lg-8 {
  width: 66.66667%; }

td.col-lg-9, th.col-lg-9 {
  width: 75%; }

td.col-lg-10, th.col-lg-10 {
  width: 83.33333%; }

td.col-lg-11, th.col-lg-11 {
  width: 91.66667%; }

td.col-lg-12, th.col-lg-12 {
  width: 100%; }

td.col-xl-1, th.col-xl-1 {
  width: 8.33333%; }

td.col-xl-2, th.col-xl-2 {
  width: 16.66667%; }

td.col-xl-3, th.col-xl-3 {
  width: 25%; }

td.col-xl-4, th.col-xl-4 {
  width: 33.33333%; }

td.col-xl-5, th.col-xl-5 {
  width: 41.66667%; }

td.col-xl-6, th.col-xl-6 {
  width: 50%; }

td.col-xl-7, th.col-xl-7 {
  width: 58.33333%; }

td.col-xl-8, th.col-xl-8 {
  width: 66.66667%; }

td.col-xl-9, th.col-xl-9 {
  width: 75%; }

td.col-xl-10, th.col-xl-10 {
  width: 83.33333%; }

td.col-xl-11, th.col-xl-11 {
  width: 91.66667%; }

td.col-xl-12, th.col-xl-12 {
  width: 100%; }

How good is Java's UUID.randomUUID?

Since most answers focused on the theory I think I can add something to the discussion by giving a practical test I did. In my database I have around 4.5 million UUIDs generated using Java 8 UUID.randomUUID(). The following ones are just some I found out:

c0f55f62-b990-47bc-8caa-f42313669948

c0f55f62-e81e-4253-8299-00b4322829d5

c0f55f62-4979-4e87-8cd9-1c556894e2bb


b9ea2498-fb32-40ef-91ef-0ba00060fe64

be87a209-2114-45b3-9d5a-86d00060fe64


4a8a74a6-e972-4069-b480-bdea1177b21f

12fb4958-bee2-4c89-8cf8-edea1177b21f

If it was truly random, the probability of having these kind of similar UUIDs would be considerably low (see edit), since we're considering only 4.5 million entries. So, although this function is good, in terms of not having collisions, for me it doesn't seem that good as it would be in theory.

Edit:

A lot of people seem to not understand this answer so I'll clarify my point: I know that the similarities are "small" and far from a full collision. However, I just wanted to compare the Java's UUID.randomUUID() with a true random number generator, which is the actual question.

In a true random number generator, the probability of the last case happening would be around = 0.007%. Therefore, I think my conclusion stands.

Formula is explained in this wiki article en.wikipedia.org/wiki/Birthday_problem

Send text to specific contact programmatically (whatsapp)

I've found the right way to do this:

Source code: phone and message are both String.

    PackageManager packageManager = context.getPackageManager();
    Intent i = new Intent(Intent.ACTION_VIEW);

    try {
        String url = "https://api.whatsapp.com/send?phone="+ phone +"&text=" + URLEncoder.encode(message, "UTF-8");
        i.setPackage("com.whatsapp");
        i.setData(Uri.parse(url));
        if (i.resolveActivity(packageManager) != null) {
            context.startActivity(i);
        }
    } catch (Exception e){
        e.printStackTrace();
    }

Enjoy yourself!

MySQL the right syntax to use near '' at line 1 error

INSERT INTO wp_bp_activity
            (
            user_id,
             component,
             `type`,
             `action`,
             content,
             primary_link,
             item_id,
             secondary_item_id,
             date_recorded,
             hide_sitewide,
             mptt_left,
             mptt_right
             )
             VALUES(
             1,'activity','activity_update','<a title="admin" href="http://brandnewmusicreleases.com/social-network/members/admin/">admin</a> posted an update','<a title="242925_1" href="http://brandnewmusicreleases.com/social-network/wp-content/uploads/242925_1.jpg" class="buddyboss-pics-picture-link">242925_1</a>','http://brandnewmusicreleases.com/social-network/members/admin/',' ',' ','2012-06-22 12:39:07',0,0,0
             )

How can I convert bigint (UNIX timestamp) to datetime in SQL Server?

For GMT, here is the easiest way:

Select dateadd(s, @UnixTime+DATEDIFF (S, GETUTCDATE(), GETDATE()), '1970-01-01')

What is the syntax for an inner join in LINQ to SQL?

You create a foreign key, and LINQ-to-SQL creates navigation properties for you. Each Dealer will then have a collection of DealerContacts which you can select, filter, and manipulate.

from contact in dealer.DealerContacts select contact

or

context.Dealers.Select(d => d.DealerContacts)

If you're not using navigation properties, you're missing out one of the main benefits on LINQ-to-SQL - the part that maps the object graph.

changing iframe source with jquery

Should work.

Here's a working example:

http://jsfiddle.net/rhpNc/

Excerpt:

function loadIframe(iframeName, url) {
    var $iframe = $('#' + iframeName);
    if ($iframe.length) {
        $iframe.attr('src',url);
        return false;
    }
    return true;
}

Using a bitmask in C#

One other really good reason to use a bitmask vs individual bools is as a web developer, when integrating one website to another, we frequently need to send parameters or flags in the querystring. As long as all of your flags are binary, it makes it much simpler to use a single value as a bitmask than send multiple values as bools. I know there are otherways to send data (GET, POST, etc.), but a simple parameter on the querystring is most of the time sufficient for nonsensitive items. Try to send 128 bool values on a querystring to communicate with an external site. This also gives the added ability of not pushing the limit on url querystrings in browsers

Laravel 5 Application Key

For me the problem was in that I had not yet ran composer update for this new project/fork. The command failed silently, nothing happened.

After running composer update it worked.

How can I show current location on a Google Map on Android Marshmallow?

Sorry but that's just much too much overhead (above), short and quick, if you have the MapFragment, you also have to map, just do the following:

if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            googleMap.setMyLocationEnabled(true)
} else {
    // Show rationale and request permission.
}

Code is in Kotlin, hope you don't mind.

have fun

Btw I think this one is a duplicate of: Show Current Location inside Google Map Fragment

How to put two divs side by side

This will work

<div style="width:800px;">
  <div style="width:300px; float:left;"></div>
  <div style="width:300px; float:right;"></div>
</div>
<div style="clear: both;"></div>

"Unable to find remote helper for 'https'" during git clone

found this in 2020 and solution solved the issue with OMZ https://stackoverflow.com/a/13018777/13222154

...
?  ~ cd $ZSH
?  .oh-my-zsh (master) ? git remote -v
origin  https://github.com/ohmyzsh/ohmyzsh.git (fetch)
origin  https://github.com/ohmyzsh/ohmyzsh.git (push)
?  .oh-my-zsh (master) ? date ; omz update
Wed Sep 30 16:16:31 CDT 2020
Updating Oh My Zsh
fatal: Unable to find remote helper for 'https'
There was an error updating. Try again later?
omz::update: restarting the zsh session...

...

    ln "$execdir/git-remote-http" "$execdir/$p" 2>/dev/null || \
    ln -s "git-remote-http" "$execdir/$p" 2>/dev/null || \
    cp "$execdir/git-remote-http" "$execdir/$p" || exit; \
done && \
./check_bindir "z$bindir" "z$execdir" "$bindir/git-add"
?  git-2.9.5 
?  git-2.9.5 
?  git-2.9.5 
?  git-2.9.5 omz update       
Updating Oh My Zsh
remote: Enumerating objects: 296, done.
remote: Counting objects: 100% (296/296), done.
remote: Compressing objects: 100% (115/115), done.
remote: Total 221 (delta 146), reused 179 (delta 105), pack-reused 0
Receiving objects: 100% (221/221), 42.89 KiB | 0 bytes/s, done.
Resolving deltas: 100% (146/146), completed with 52 local objects.
From https://github.com/ohmyzsh/ohmyzsh
 * branch            master     -> FETCH_HEAD
   7deda85..f776af2  master     -> origin/master
Created autostash: 273f6e9

Adding link a href to an element using css

No. Its not possible to add link through css. But you can use jquery

$('.case').each(function() {
  var link = $(this).html();
  $(this).contents().wrap('<a href="example.com/script.php?id="></a>');
});

Here the demo: http://jsfiddle.net/r5uWX/1/

How do I get the result of a command in a variable in windows?

If you're looking for the solution provided in Using the result of a command as an argument in bash?

then here is the code:

@echo off
if not "%1"=="" goto get_basename_pwd
for /f "delims=X" %%i in ('cd') do call %0 %%i
for /f "delims=X" %%i in ('dir /o:d /b') do echo %%i>>%filename%.txt
goto end

:get_basename_pwd
set filename=%~n1

:end
  • This will call itself with the result of the CD command, same as pwd.
  • String extraction on parameters will return the filename/folder.
  • Get the contents of this folder and append to the filename.txt

[Credits]: Thanks to all the other answers and some digging on the Windows XP commands page.

Which UUID version to use?

There are two different ways of generating a UUID.

If you just need a unique ID, you want a version 1 or version 4.

  • Version 1: This generates a unique ID based on a network card MAC address and a timer. These IDs are easy to predict (given one, I might be able to guess another one) and can be traced back to your network card. It's not recommended to create these.

  • Version 4: These are generated from random (or pseudo-random) numbers. If you just need to generate a UUID, this is probably what you want.

If you need to always generate the same UUID from a given name, you want a version 3 or version 5.

  • Version 3: This generates a unique ID from an MD5 hash of a namespace and name. If you need backwards compatibility (with another system that generates UUIDs from names), use this.

  • Version 5: This generates a unique ID from an SHA-1 hash of a namespace and name. This is the preferred version.

Why is super.super.method(); not allowed in Java?

Calling of super.super.method() make sense when you can't change code of base class. This often happens when you are extending an existing library.

Ask yourself first, why are you extending that class? If answer is "because I can't change it" then you can create exact package and class in your application, and rewrite naughty method or create delegate:

package com.company.application;

public class OneYouWantExtend extends OneThatContainsDesiredMethod {

    // one way is to rewrite method() to call super.method() only or 
    // to doStuff() and then call super.method()

    public void method() {
        if (isDoStuff()) {
            // do stuff
        }
        super.method();
    }

    protected abstract boolean isDoStuff();


    // second way is to define methodDelegate() that will call hidden super.method()

    public void methodDelegate() {
        super.method();
    }
    ...
}

public class OneThatContainsDesiredMethod {

    public void method() {...}
    ...
}

For instance, you can create org.springframework.test.context.junit4.SpringJUnit4ClassRunner class in your application so this class should be loaded before the real one from jar. Then rewrite methods or constructors.

Attention: This is absolute hack, and it is highly NOT recommended to use but it's WORKING! Using of this approach is dangerous because of possible issues with class loaders. Also this may cause issues each time you will update library that contains overwritten class.

Call a function with argument list in python

You need to use arguments unpacking..

def wrapper(func, *args):
    func(*args)

def func1(x):
    print(x)

def func2(x, y, z):
    print x+y+z

wrapper(func1, 1)
wrapper(func2, 1, 2, 3)

Read file from aws s3 bucket using node fs

I couldn't figure why yet, but the createReadStream/pipe approach didn't work for me. I was trying to download a large CSV file (300MB+) and I got duplicated lines. It seemed a random issue. The final file size varied in each attempt to download it.

I ended up using another way, based on AWS JS SDK examples:

var s3 = new AWS.S3();
var params = {Bucket: 'myBucket', Key: 'myImageFile.jpg'};
var file = require('fs').createWriteStream('/path/to/file.jpg');

s3.getObject(params).
    on('httpData', function(chunk) { file.write(chunk); }).
    on('httpDone', function() { file.end(); }).
    send();

This way, it worked like a charm.

How to find a value in an array and remove it by using PHP array functions?

Okay, this is a bit longer, but does a couple of cool things.

I was trying to filter a list of emails but exclude certain domains and emails.

Script below will...

  1. Remove any records with a certain domain
  2. Remove any email with an exact value.

First you need an array with a list of emails and then you can add certain domains or individual email accounts to exclusion lists.

Then it will output a list of clean records at the end.

//list of domains to exclude
$excluded_domains = array(
    "domain1.com",
);

//list of emails to exclude
$excluded_emails = array(
    "[email protected]",
    "[email protected]",    
);

function get_domain($email) {

    $domain = explode("@", $email);
    $domain = $domain[1];
    return $domain;

}

//loop through list of emails
foreach($emails as $email) {

    //set false flag
    $exclude = false;

    //extract the domain from the email     
    $domain = get_domain($email);

    //check if the domain is in the exclude domains list
    if(in_array($domain, $excluded_domains)){
        $exclude = true;
    }

    //check if the domain is in the exclude emails list
    if(in_array($email, $excluded_emails)){
        $exclude = true;
    } 

    //if its not excluded add it to the final array
    if($exclude == false) {
        $clean_email_list[] = $email;
    }

    $count = $count + 1;
}

print_r($clean_email_list);

Changing the interval of SetInterval while it's running

This is my way of doing this, i use setTimeout:

var timer = {
    running: false,
    iv: 5000,
    timeout: false,
    cb : function(){},
    start : function(cb,iv){
        var elm = this;
        clearInterval(this.timeout);
        this.running = true;
        if(cb) this.cb = cb;
        if(iv) this.iv = iv;
        this.timeout = setTimeout(function(){elm.execute(elm)}, this.iv);
    },
    execute : function(e){
        if(!e.running) return false;
        e.cb();
        e.start();
    },
    stop : function(){
        this.running = false;
    },
    set_interval : function(iv){
        clearInterval(this.timeout);
        this.start(false, iv);
    }
};

Usage:

timer.start(function(){
    console.debug('go');
}, 2000);

timer.set_interval(500);

timer.stop();

MySQL "ERROR 1005 (HY000): Can't create table 'foo.#sql-12c_4' (errno: 150)"

all, I solved a problem and wanted to share it:

I had this error <> The issue was in that in my statement:

alter table system_registro_de_modificacion add foreign key (usuariomodificador_id) REFERENCES Usuario(id) On delete restrict;

I had incorrectly written the CASING: it works in Windows WAMP, but in Linux MySQL it is more strict with the CASING, so writting "Usuario" instead of "usuario" (exact casing), generated the error, and was corrected simply changing the casing.

Django - Reverse for '' not found. '' is not a valid view function or pattern name

In my case, what I did was a mistake in the url tag in the respective template. So, in my url tag I had something like

{% url 'polls:details' question.id %}

while in the views, I had written something like:

def details(request, question_id): code here

So, the first thing you might wanna check is whether things are spelled as they shoould be. The next thing then you can do is as the people above have suggested.

Node Express sending image files as API response

a proper solution with streams and error handling is below:

const fs = require('fs')
const stream = require('stream')

app.get('/report/:chart_id/:user_id',(req, res) => {
  const r = fs.createReadStream('path to file') // or any other way to get a readable stream
  const ps = new stream.PassThrough() // <---- this makes a trick with stream error handling
  stream.pipeline(
   r,
   ps, // <---- this makes a trick with stream error handling
   (err) => {
    if (err) {
      console.log(err) // No such file or any other kind of error
      return res.sendStatus(400); 
    }
  })
  ps.pipe(res) // <---- this makes a trick with stream error handling
})

with Node older then 10 you will need to use pump instead of pipeline.

How is CountDownLatch used in Java Multithreading?

If you add some debug after your call to latch.countDown(), this may help you understand its behaviour better.

latch.countDown();
System.out.println("DONE "+this.latch); // Add this debug

The output will show the Count being decremented. This 'count' is effectively the number of Runnable tasks (Processor objects) you've started against which countDown() has not been invoked and hence is blocked the main thread on its call to latch.await().

DONE java.util.concurrent.CountDownLatch@70e69696[Count = 2]
DONE java.util.concurrent.CountDownLatch@70e69696[Count = 1]
DONE java.util.concurrent.CountDownLatch@70e69696[Count = 0]

How to change package name in flutter?

If you don’t like changing files in such a way then alternative way would be to use this package.

https://pub.dev/packages/rename

rename --bundleId com.newpackage.appname
pub global run rename --appname "Your New App Name"

Using this, you simply run these 2 commands in your terminal and your app name and identifiers will be changed.pub global run

Android- Error:Execution failed for task ':app:transformClassesWithDexForRelease'

So, mine didn't get resolved by adding the multiDexEnabled flag. It actually was there before getting the error message.

What resolved the error for me was making sure I was using the same version of all play-services libraries. In one library I had 11.8.0 but in the app that consumes the library I was using 11.6.0 and that difference was what caused the error message.

So, instead of changing your libraries to a specific version like previous answers, maybe you wanna check you're using the same version all across since mixing versions is explicitly discouraged by Android Studio by warnings.

How to install Hibernate Tools in Eclipse?

Once you have copied the plugins and features folder to eclipse (eg. c:\program files\eclipse (or whereever you installed it). You will see a features and plugins folder there already) you can check if hibernate has installed by going to Help > Software updates > installed software. If hibernate is not listed close eclipse and launch it again via a command window with this command "eclipse -clean".

How can I get useful error messages in PHP?

Aside from error_reporting and the display_errors ini setting, you can get SYNTAX errors from your web server's log files. When I'm developing PHP I load my development system's web server logs into my editor. Whenever I test a page and get a blank screen, the log file goes stale and my editor asks if I want to reload it. When I do, I jump to the bottom and there is the syntax error. For example:

[Sun Apr 19 19:09:11 2009] [error] [client 127.0.0.1] PHP Parse error:  syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING in D:\\webroot\\test\\test.php on line 9

Jquery Date picker Default Date

While the defaultDate does not set the widget. What is needed is something like:

$(".datepicker").datepicker({
    showButtonPanel: true,
    numberOfMonths: 2

});

$(".datepicker[value='']").datepicker("setDate", "-0d"); 

Excel VBA - Sum up a column

I think you are misinterpreting the source of the error; rExternalTotal appears to be equal to a single cell. rReportData.offset(0,0) is equal to rReportData
rReportData.offset(261,0).end(xlUp) is likely also equal to rReportData, as you offset by 261 rows and then use the .end(xlUp) function which selects the top of a contiguous data range.
If you are interested in the sum of just a column, you can just refer to the whole column:

dExternalTotal = Application.WorksheetFunction.Sum(columns("A:A"))

or

dExternalTotal = Application.WorksheetFunction.Sum(columns((rReportData.column))

The worksheet function sum will correctly ignore blank spaces.

Let me know if this helps!

How to count number of records per day?

If your timestamp includes time, not only date, use:

SELECT DATE_FORMAT('timestamp', '%Y-%m-%d') AS date, COUNT(id) AS count FROM table GROUP BY DATE_FORMAT('timestamp', '%Y-%m-%d')

How to increase apache timeout directive in .htaccess?

This solution is for Litespeed Server (Apache as well)

Add the following code in .htaccess

RewriteRule .* - [E=noabort:1]
RewriteRule .* - [E=noconntimeout:1]

Litespeed reference

How can one tell the version of React running at runtime in the browser?

From command line to view react version, npm view react version

Is False == 0 and True == 1 an implementation detail or is it guaranteed by the language?

In Python 2.x, it is not guaranteed at all:

>>> False = 5
>>> 0 == False
False

So it could change. In Python 3.x, True, False, and None are reserved words, so the above code would not work.

In general, with booleans you should assume that while False will always have an integer value of 0 (so long as you don't change it, as above), True could have any other value. I wouldn't necessarily rely on any guarantee that True==1, but on Python 3.x, this will always be the case, no matter what.

How to remove the Flutter debug banner?

how to remove debug banner in flutter

Just add debugShowCheckedModeBanner: false in MaterialApp.

3 ways - Remove Debug Banner In Flutter

How do I disable TextBox using JavaScript?

You can use disabled attribute to disable the textbox.

document.getElementById('color').disabled = true;

Does WhatsApp offer an open API?

  1. is the correct answer. WhatsApp is intentionally a closed system without an API for external access.

There were several projects available that reverse engineered the WhatsApp webservice interfaces. However, to my knowledge all of them are now discontinued/defunct due to legal action against them from WhatsApp.

For mobile phone applications there is a limited URL-Scheme-API available on IPhone and Android (Android-intent possible as well).

CSS, Images, JS not loading in IIS

If you're seeing 403 errors in your browser console, check your MVC Bundle Config. Bundle names should not match any existing folder names in your project.

eg.

bundles.Add(new StyleBundle("~/Content/css")...

...would cause issues for IIS if the folder structure $(ProjectDir)\Content\css exists in your project, since it tries to look within the existing folder for bundle content that's not there.

Instead just use something like:

bundles.Add(new StyleBundle("~/Content/cssbundle")...

In an array of objects, fastest way to find the index of an object whose attributes match a search

The simplest and easiest way to find element index in array.

ES5 syntax: [{id:1},{id:2},{id:3},{id:4}].findIndex(function(obj){return obj.id == 3})

ES6 syntax: [{id:1},{id:2},{id:3},{id:4}].findIndex(obj => obj.id == 3)

How to reverse an animation on mouse out after hover

Using transform in combination with transition works flawlessly for me:

.ani-grow {
    -webkit-transition: all 0.5s ease; 
    -moz-transition: all 0.5s ease; 
    -o-transition: all 0.5s ease; 
    -ms-transition: all 0.5s ease; 
    transition: all 0.5s ease; 
}
.ani-grow:hover {
    transform: scale(1.01);
}

css selector to match an element without attribute x

For a more cross-browser solution you could style all inputs the way you want the non-typed, text, and password then another style the overrides that style for radios, checkboxes, etc.

input { border:solid 1px red; }

input[type=radio], 
input[type=checkbox], 
input[type=submit], 
input[type=reset], 
input[type=file] 
      { border:none; }

- Or -

could whatever part of your code that is generating the non-typed inputs give them a class like .no-type or simply not output at all? Additionally this type of selection could be done with jQuery.

jquery multiple checkboxes array

var checkedString = $('input:checkbox:checked.name').map(function() { return this.value; }).get().join();

how to convert milliseconds to date format in android?

i finally find normal code that works for me

Long longDate = Long.valueOf(date);

Calendar cal = Calendar.getInstance();
int offset = cal.getTimeZone().getOffset(cal.getTimeInMillis());
Date da = new Date(); 
da = new Date(longDate-(long)offset);
cal.setTime(da);

String time =cal.getTime().toLocaleString(); 
//this is full string        

time = DateFormat.getTimeInstance(DateFormat.MEDIUM).format(da);
//this is only time

time = DateFormat.getDateInstance(DateFormat.MEDIUM).format(da);
//this is only date

Convert normal date to unix timestamp

You can use Date.parse(), but the input formats that it accepts are implementation-dependent. However, if you can convert the date to ISO format (YYYY-MM-DD), most implementations should understand it.

See Why does Date.parse give incorrect results?.

Bootstrap modal link

Please remove . from your target it should be a id

<a href="#bannerformmodal" data-toggle="modal" data-target="#bannerformmodal">Load me</a>

Also you have to give your modal id like below

<div class="modal fade bannerformmodal" tabindex="-1" role="dialog" aria-labelledby="bannerformmodal" aria-hidden="true" id="bannerformmodal">

Here is the solution in a fiddle.

CSS class for pointer cursor

There is no classes for that. But you can add inline style for your div or other elements like,

<div class="" style="cursor: pointer;">

Pandas: ValueError: cannot convert float NaN to integer

ValueError: cannot convert float NaN to integer

From v0.24, you actually can. Pandas introduces Nullable Integer Data Types which allows integers to coexist with NaNs.

Given a series of whole float numbers with missing data,

s = pd.Series([1.0, 2.0, np.nan, 4.0])
s

0    1.0
1    2.0
2    NaN
3    4.0
dtype: float64

s.dtype
# dtype('float64')

You can convert it to a nullable int type (choose from one of Int16, Int32, or Int64) with,

s2 = s.astype('Int32') # note the 'I' is uppercase
s2

0      1
1      2
2    NaN
3      4
dtype: Int32

s2.dtype
# Int32Dtype()

Your column needs to have whole numbers for the cast to happen. Anything else will raise a TypeError:

s = pd.Series([1.1, 2.0, np.nan, 4.0])

s.astype('Int32')
# TypeError: cannot safely cast non-equivalent float64 to int32

Convert an array into an ArrayList

This will give you a list.

List<Card> cardsList = Arrays.asList(hand);

If you want an arraylist, you can do

ArrayList<Card> cardsList = new ArrayList<Card>(Arrays.asList(hand));

How to change identity column values programmatically?

Through the UI in SQL Server 2005 manager, change the column remove the autonumber (identity) property of the column (select the table by right clicking on it and choose "Design").

Then run your query:

UPDATE table SET Id = Id + 1

Then go and add the autonumber property back to the column.

jQuery UI 1.10: dialog and zIndex option

Add zIndex property to dialog object:

$(elm).dialog(
 zIndex: 10000
);

How to download a file using a Java REST service and a data stream

"How can I directly (without saving the file on 2nd server) download the file from 1st server to client's machine?"

Just use the Client API and get the InputStream from the response

Client client = ClientBuilder.newClient();
String url = "...";
final InputStream responseStream = client.target(url).request().get(InputStream.class);

There are two flavors to get the InputStream. You can also use

Response response = client.target(url).request().get();
InputStream is = (InputStream)response.getEntity();

Which one is the more efficient? I'm not sure, but the returned InputStreams are different classes, so you may want to look into that if you care to.

From 2nd server I can get a ByteArrayOutputStream to get the file from 1st server, can I pass this stream further to the client using the REST service?

So most of the answers you'll see in the link provided by @GradyGCooper seem to favor the use of StreamingOutput. An example implementation might be something like

final InputStream responseStream = client.target(url).request().get(InputStream.class);
System.out.println(responseStream.getClass());
StreamingOutput output = new StreamingOutput() {
    @Override
    public void write(OutputStream out) throws IOException, WebApplicationException {  
        int length;
        byte[] buffer = new byte[1024];
        while((length = responseStream.read(buffer)) != -1) {
            out.write(buffer, 0, length);
        }
        out.flush();
        responseStream.close();
    }   
};
return Response.ok(output).header(
        "Content-Disposition", "attachment, filename=\"...\"").build();

But if we look at the source code for StreamingOutputProvider, you'll see in the writeTo, that it simply writes the data from one stream to another. So with our implementation above, we have to write twice.

How can we get only one write? Simple return the InputStream as the Response

final InputStream responseStream = client.target(url).request().get(InputStream.class);
return Response.ok(responseStream).header(
        "Content-Disposition", "attachment, filename=\"...\"").build();

If we look at the source code for InputStreamProvider, it simply delegates to ReadWriter.writeTo(in, out), which simply does what we did above in the StreamingOutput implementation

 public static void writeTo(InputStream in, OutputStream out) throws IOException {
    int read;
    final byte[] data = new byte[BUFFER_SIZE];
    while ((read = in.read(data)) != -1) {
        out.write(data, 0, read);
    }
}

Asides:

  • Client objects are expensive resources. You may want to reuse the same Client for request. You can extract a WebTarget from the client for each request.

    WebTarget target = client.target(url);
    InputStream is = target.request().get(InputStream.class);
    

    I think the WebTarget can even be shared. I can't find anything in the Jersey 2.x documentation (only because it is a larger document, and I'm too lazy to scan through it right now :-), but in the Jersey 1.x documentation, it says the Client and WebResource (which is equivalent to WebTarget in 2.x) can be shared between threads. So I'm guessing Jersey 2.x would be the same. but you may want to confirm for yourself.

  • You don't have to make use of the Client API. A download can be easily achieved with the java.net package APIs. But since you're already using Jersey, it doesn't hurt to use its APIs

  • The above is assuming Jersey 2.x. For Jersey 1.x, a simple Google search should get you a bunch of hits for working with the API (or the documentation I linked to above)


UPDATE

I'm such a dufus. While the OP and I are contemplating ways to turn a ByteArrayOutputStream to an InputStream, I missed the simplest solution, which is simply to write a MessageBodyWriter for the ByteArrayOutputStream

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;

@Provider
public class OutputStreamWriter implements MessageBodyWriter<ByteArrayOutputStream> {

    @Override
    public boolean isWriteable(Class<?> type, Type genericType,
            Annotation[] annotations, MediaType mediaType) {
        return ByteArrayOutputStream.class == type;
    }

    @Override
    public long getSize(ByteArrayOutputStream t, Class<?> type, Type genericType,
            Annotation[] annotations, MediaType mediaType) {
        return -1;
    }

    @Override
    public void writeTo(ByteArrayOutputStream t, Class<?> type, Type genericType,
            Annotation[] annotations, MediaType mediaType,
            MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream)
            throws IOException, WebApplicationException {
        t.writeTo(entityStream);
    }
}

Then we can simply return the ByteArrayOutputStream in the response

return Response.ok(baos).build();

D'OH!

UPDATE 2

Here are the tests I used (

Resource class

@Path("test")
public class TestResource {

    final String path = "some_150_mb_file";

    @GET
    @Produces(MediaType.APPLICATION_OCTET_STREAM)
    public Response doTest() throws Exception {
        InputStream is = new FileInputStream(path);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        int len;
        byte[] buffer = new byte[4096];
        while ((len = is.read(buffer, 0, buffer.length)) != -1) {
            baos.write(buffer, 0, len);
        }
        System.out.println("Server size: " + baos.size());
        return Response.ok(baos).build();
    }
}

Client test

public class Main {
    public static void main(String[] args) throws Exception {
        Client client = ClientBuilder.newClient();
        String url = "http://localhost:8080/api/test";
        Response response = client.target(url).request().get();
        String location = "some_location";
        FileOutputStream out = new FileOutputStream(location);
        InputStream is = (InputStream)response.getEntity();
        int len = 0;
        byte[] buffer = new byte[4096];
        while((len = is.read(buffer)) != -1) {
            out.write(buffer, 0, len);
        }
        out.flush();
        out.close();
        is.close();
    }
}

UPDATE 3

So the final solution for this particular use case was for the OP to simply pass the OutputStream from the StreamingOutput's write method. Seems the third-party API, required a OutputStream as an argument.

StreamingOutput output = new StreamingOutput() {
    @Override
    public void write(OutputStream out) {
        thirdPartyApi.downloadFile(.., .., .., out);
    }
}
return Response.ok(output).build();

Not quite sure, but seems the reading/writing within the resource method, using ByteArrayOutputStream`, realized something into memory.

The point of the downloadFile method accepting an OutputStream is so that it can write the result directly to the OutputStream provided. For instance a FileOutputStream, if you wrote it to file, while the download is coming in, it would get directly streamed to the file.

It's not meant for us to keep a reference to the OutputStream, as you were trying to do with the baos, which is where the memory realization comes in.

So with the way that works, we are writing directly to the response stream provided for us. The method write doesn't actually get called until the writeTo method (in the MessageBodyWriter), where the OutputStream is passed to it.

You can get a better picture looking at the MessageBodyWriter I wrote. Basically in the writeTo method, replace the ByteArrayOutputStream with StreamingOutput, then inside the method, call streamingOutput.write(entityStream). You can see the link I provided in the earlier part of the answer, where I link to the StreamingOutputProvider. This is exactly what happens

Error in strings.xml file in Android

1. for error: unescaped apostrophe in string

what I found is that AAPT2 tool points to wrong row in xml, sometimes. So you should correct whole strings.xml file

In Android Studio, in problem file use :

Edit->find->replace

Then write in first field \' (or \&,>,\<,\")
in second put '(or &,>,<,")
then replace each if needed.(or "reptlace all" in case with ')
Then in first field again put '(or &,>,<,")
and in second write \'
then replace each if needed.(or "replace all" in case with ')

2. for other problematic symbols
I use to comment each next half part +rebuild until i won't find the wrong sign.

E.g. an escaped word "\update" unexpectedly drops such error :)

Clicking submit button of an HTML form by a Javascript code

You can do :

document.forms["loginForm"].submit()

But this won't call the onclick action of your button, so you will need to call it by hand.

Be aware that you must use the name of your form and not the id to access it.

Easiest way to compare arrays in C#

This LINQ solution works, not sure how it compares in performance to SequenceEquals. But it handles different array lengths and the .All will exit on the first item that is not equal without iterating through the whole array.

private static bool arraysEqual<T>(IList<T> arr1, IList<T> arr2)
        =>
            ReferenceEquals(arr1, arr2) || (
                arr1 != null && arr2 != null &&
                arr1.Count == arr2.Count &&
                arr1.Select((a, i) => arr2[i].Equals(a)).All(i => i)
            );

How to check Grants Permissions at Run-Time?

You can also query by following code snippet as backward compatible;

int hasPermission = ContextCompat.checkSelfPermission(this,Manifest.permission.WRITE_CONTACTS);
if (hasPermission == PackageManager.PERMISSION_GRANTED) {
    //Do smthng
}

Get an element by index in jQuery

$(...)[index]      // gives you the DOM element at index
$(...).get(index)  // gives you the DOM element at index
$(...).eq(index)   // gives you the jQuery object of element at index

DOM objects don't have css function, use the last...

$('ul li').eq(index).css({'background-color':'#343434'});

docs:

.get(index) Returns: Element

.eq(index) Returns: jQuery

Move SQL Server 2008 database files to a new folder location

Some notes to complement the ALTER DATABASE process:

1) You can obtain a full list of databases with logical names and full paths of MDF and LDF files:

   USE master SELECT name, physical_name FROM sys.master_files

2) You can move manually the files with CMD move command:

Move "Source" "Destination"

Example:

md "D:\MSSQLData"
Move "C:\test\SYSADMIT-DB.mdf" "D:\MSSQLData\SYSADMIT-DB_Data.mdf"
Move "C:\test\SYSADMIT-DB_log.ldf" "D:\MSSQLData\SYSADMIT-DB_log.ldf"

3) You should change the default database path for new databases creation. The default path is obtained from the Windows registry.

You can also change with T-SQL, for example, to set default destination to: D:\MSSQLData

USE [master]

GO

EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE', N'Software\Microsoft\MSSQLServer\MSSQLServer', N'DefaultData', REG_SZ, N'D:\MSSQLData'

GO

EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE', N'Software\Microsoft\MSSQLServer\MSSQLServer', N'DefaultLog', REG_SZ, N'D:\MSSQLData'

GO

Extracted from: http://www.sysadmit.com/2016/08/mover-base-de-datos-sql-server-a-otro-disco.html

PHP remove commas from numeric strings

Not tested, but probably something like if(preg_match("/^[0-9,]+$/", $a)) $a = str_replace(...)


Do it the other way around:

$a = "1,435";
$b = str_replace( ',', '', $a );

if( is_numeric( $b ) ) {
    $a = $b;
}

The easiest would be:

$var = intval(preg_replace('/[^\d.]/', '', $var));

or if you need float:

$var = floatval(preg_replace('/[^\d.]/', '', $var));

How to to send mail using gmail in Laravel?

if you still could be able to send mail after setting all configs right and get forbidden or timeout errors you could set the allow less secure apps to access your account in gmail. you can follow how to here

How to limit text width

Try

<div style="max-width:200px; word-wrap:break-word;">Texttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt</div>

Create Excel file in Java

Flat files do not allow providing meta information.

I would suggest writing out a HTML table containing the information you need, and let Excel read it instead. You can then use <b> tags to do what you ask for.

Close a MessageBox after several seconds

I know this question is 8 year old, however there was and is a better solution for this purpose. It's always been there, and still is: User32.dll!MessageBoxTimeout.

This is an undocumented function used by Microsoft Windows, and it does exactly what you want and even more. It supports different languages as well.

C# Import:

[DllImport("user32.dll", SetLastError = true)]
public static extern int MessageBoxTimeout(IntPtr hWnd, String lpText, String lpCaption, uint uType, Int16 wLanguageId, Int32 dwMilliseconds);

[DllImport("user32.dll", SetLastError = true)]
public static extern IntPtr GetForegroundWindow();

How to use it in C#:

uint uiFlags = /*MB_OK*/ 0x00000000 | /*MB_SETFOREGROUND*/  0x00010000 | /*MB_SYSTEMMODAL*/ 0x00001000 | /*MB_ICONEXCLAMATION*/ 0x00000030;

NativeFunctions.MessageBoxTimeout(NativeFunctions.GetForegroundWindow(), $"Kitty", $"Hello", uiFlags, 0, 5000);

Work smarter, not harder.

How to show grep result with complete path or file name

I fall here when I was looking exactly for the same problem and maybe it can help other.

I think the real solution is:

cat *.log | grep -H somethingtosearch

How to redirect to Index from another controller?

Complete answer (.Net Core 3.1)

Most answers here are correct but taken a bit out of context, so I will provide a full-fledged answer which works for Asp.Net Core 3.1. For completeness' sake:

[Route("health")]
[ApiController]
public class HealthController : Controller
{
    [HttpGet("some_health_url")]
    public ActionResult SomeHealthMethod() {}
}

[Route("v2")]
[ApiController]
public class V2Controller : Controller
{
    [HttpGet("some_url")]
    public ActionResult SomeV2Method()
    {
        return RedirectToAction("SomeHealthMethod", "Health"); // omit "Controller"
    }
}

If you try to use any of the url-specific strings, e.g. "some_health_url", it will not work!

socket.error:[errno 99] cannot assign requested address and namespace in python

This error will also appear if you try to connect to an exposed port from within a Docker container, when nothing is actively serving the port.

On a host where nothing is listening/bound to that port you'd get a No connection could be made because the target machine actively refused it error instead when making a request to a local URL that is not served, eg: localhost:5000. However, if you start a container that binds to the port, but there is no server running inside of it actually serving the port, any requests to that port on localhost will result in:

  • [Errno 99] Cannot assign requested address (if called from within the container), or
  • [Errno 0] Error (if called from outside of the container).

You can reproduce this error and the behaviour described above as follows:

Start a dummy container (note: this will pull the python image if not found locally):

docker run --name serv1 -p 5000:5000 -dit python

Then for [Errno 0] Error enter a Python console on host, while for [Errno 99] Cannot assign requested address access a Python console on the container by calling:

docker exec -it -u 0 serv1 python

And then in either case call:

import urllib.request
urllib.request.urlopen('https://localhost:5000')

I concluded with treating either of these errors as equivalent to No connection could be made because the target machine actively refused it rather than trying to fix their cause - although please advise if that's a bad idea.


I've spent over a day figuring this one out, given that all resources and answers I could find on the [Errno 99] Cannot assign requested address point in the direction of binding to an occupied port, connecting to an invalid IP, sysctl conflicts, docker network issues, TIME_WAIT being incorrect, and many more things. Therefore I wanted to leave this answer here, despite not being a direct answer to the question at hand, given that it can be a common cause for the error described in this question.

Download multiple files as a zip-file using php

You are ready to do with php zip lib, and can use zend zip lib too,

<?PHP
// create object
$zip = new ZipArchive();   

// open archive 
if ($zip->open('app-0.09.zip') !== TRUE) {
    die ("Could not open archive");
}

// get number of files in archive
$numFiles = $zip->numFiles;

// iterate over file list
// print details of each file
for ($x=0; $x<$numFiles; $x++) {
    $file = $zip->statIndex($x);
    printf("%s (%d bytes)", $file['name'], $file['size']);
    print "
";    
}

// close archive
$zip->close();
?>

http://devzone.zend.com/985/dynamically-creating-compressed-zip-archives-with-php/

and there is also php pear lib for this http://www.php.net/manual/en/class.ziparchive.php

MySQL timestamp select date range

This SQL query will extract the data for you. It is easy and fast.

SELECT *
  FROM table_name
  WHERE extract( YEAR_MONTH from timestamp)="201010";

get Context in non-Activity class

If your class is non-activity class, and creating an instance of it from the activiy, you can pass an instance of context via constructor of the later as follows:

class YourNonActivityClass{

// variable to hold context
private Context context;

//save the context recievied via constructor in a local variable

public YourNonActivityClass(Context context){
    this.context=context;
}

}

You can create instance of this class from the activity as follows:

new YourNonActivityClass(this);

CSS3 :unchecked pseudo-class

The way I handled this was switching the className of a label based on a condition. This way you only need one label and you can have different classes for different states... Hope that helps!

How to create an alert message in jsp page after submit process is complete

in your servlet

 request.setAttribute("submitDone","done");
 return mapping.findForward("success");

In your jsp

<c:if test="${not empty submitDone}">
  <script>alert("Form submitted");
</script></c:if>

Dropping a connected user from an Oracle 10g database schema

To find the sessions, as a DBA use

select sid,serial# from v$session where username = '<your_schema>'

If you want to be sure only to get the sessions that use SQL Developer, you can add and program = 'SQL Developer'. If you only want to kill sessions belonging to a specific developer, you can add a restriction on os_user

Then kill them with

alter system kill session '<sid>,<serial#>'

(e.g. alter system kill session '39,1232')

A query that produces ready-built kill-statements could be

select 'alter system kill session ''' || sid || ',' || serial# || ''';' from v$session where username = '<your_schema>'

This will return one kill statement per session for that user - something like:

alter system kill session '375,64855';

alter system kill session '346,53146';

iPhone system font

Category UIFontSystemFonts for UIFont (UIInterface.h) provides several convenient predefined sizes.

@interface UIFont (UIFontSystemFonts)
 + (CGFloat)labelFontSize;
 + (CGFloat)buttonFontSize;
 + (CGFloat)smallSystemFontSize;
 + (CGFloat)systemFontSize;
@end 

I use it for chat messages (labels) and it work well when I need to get size of text blocks.

 [UIFont systemFontOfSize:[UIFont labelFontSize]];

Happy coding!

How to write new line character to a file in Java

This approach always works for me:

String newLine = System.getProperty("line.separator");
String textInNewLine = "this is my first line " + newLine + "this is my second 
line ";

Distribution certificate / private key not installed

In my case Xcode was not accessing certificates from the keychain, I followed these steps:

  1. delete certificates from the keychain.
  2. restart the mac.
  3. generate new certificates.
  4. install new certificates.
  5. clean build folder.
  6. build project.
  7. again clean build folder.
  8. archive now. It works That's it.

what is the multicast doing on 224.0.0.251?

I deactivated my "Arno's Iptables Firewall" for testing, and then the messages are gone

Looping Over Result Sets in MySQL

Something like this should do the trick (However, read after the snippet for more info)

CREATE PROCEDURE GetFilteredData()
BEGIN
  DECLARE bDone INT;

  DECLARE var1 CHAR(16);    -- or approriate type
  DECLARE Var2 INT;
  DECLARE Var3 VARCHAR(50);

  DECLARE curs CURSOR FOR  SELECT something FROM somewhere WHERE some stuff;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;

  DROP TEMPORARY TABLE IF EXISTS tblResults;
  CREATE TEMPORARY TABLE IF NOT EXISTS tblResults  (
    --Fld1 type,
    --Fld2 type,
    --...
  );

  OPEN curs;

  SET bDone = 0;
  REPEAT
    FETCH curs INTO var1,, b;

    IF whatever_filtering_desired
       -- here for whatever_transformation_may_be_desired
       INSERT INTO tblResults VALUES (var1, var2, var3 ...);
    END IF;
  UNTIL bDone END REPEAT;

  CLOSE curs;
  SELECT * FROM tblResults;
END

A few things to consider...

Concerning the snippet above:

  • may want to pass part of the query to the Stored Procedure, maybe particularly the search criteria, to make it more generic.
  • If this method is to be called by multiple sessions etc. may want to pass a Session ID of sort to create a unique temporary table name (actually unnecessary concern since different sessions do not share the same temporary file namespace; see comment by Gruber, below)
  • A few parts such as the variable declarations, the SELECT query etc. need to be properly specified

More generally: trying to avoid needing a cursor.

I purposely named the cursor variable curs[e], because cursors are a mixed blessing. They can help us implement complicated business rules that may be difficult to express in the declarative form of SQL, but it then brings us to use the procedural (imperative) form of SQL, which is a general feature of SQL which is neither very friendly/expressive, programming-wise, and often less efficient performance-wise.

Maybe you can look into expressing the transformation and filtering desired in the context of a "plain" (declarative) SQL query.

How to group pandas DataFrame entries by date in a non-unique column

this will also work

data.groupby(data['date'].dt.year)

How can I perform a reverse string search in Excel without using VBA?

I found this on google, tested in Excel 2003 & it works for me:

=IF(COUNTIF(A1,"* *"),RIGHT(A1,LEN(A1)-LOOKUP(LEN(A1),FIND(" ",A1,ROW(INDEX($A:$A,1,1):INDEX($A:$A,LEN(A1),1))))),A1)

[edit] I don't have enough rep to comment, so this seems the best place...BradC's answer also doesn't work with trailing spaces or empty cells...
[2nd edit] actually, it doesn't work for single words either...

Get record counts for all tables in MySQL database

This is what I do to get the actual count (no using the schema)

It's slower but more accurate.

It's a two step process at

  1. Get list of tables for your db. You can get it using

    mysql -uroot -p mydb -e "show tables"
    
  2. Create and assign the list of tables to the array variable in this bash script (separated by a single space just like in the code below)

    array=( table1 table2 table3 )
    
    for i in "${array[@]}"
    do
        echo $i
        mysql -uroot mydb -e "select count(*) from $i"
    done
    
  3. Run it:

    chmod +x script.sh; ./script.sh
    

does linux shell support list data structure?

For make a list, simply do that

colors=(red orange white "light gray")

Technically is an array, but - of course - it has all list features.
Even python list are implemented with array

Disable sorting for a particular column in jQuery DataTables

"aoColumnDefs" : [   
{
  'bSortable' : false,  
  'aTargets' : [ 0 ]
}]

Here 0 is the index of the column, if you want multiple columns to be not sorted, mention column index values seperated by comma(,)

Matplotlib tight_layout() doesn't take into account figure suptitle

You can adjust the subplot geometry in the very tight_layout call as follows:

fig.tight_layout(rect=[0, 0.03, 1, 0.95])

As it's stated in the documentation (https://matplotlib.org/users/tight_layout_guide.html):

tight_layout() only considers ticklabels, axis labels, and titles. Thus, other artists may be clipped and also may overlap.

Permission denied (publickey,gssapi-keyex,gssapi-with-mic)

The trick here is to use the -C (comment) parameter to specify your GCE userid. It looks like Google introduced this change last in 2018.

If the Google user who owns the GCE instance is [email protected] (which you will use as your login userid), then generate the key pair with (for example)

ssh-keygen -b521 -t ecdsa -C myname -f mykeypair

When you paste mykeypair.pub into the instance's public key list, you should see "myname" appear as the userid of the key.

Setting this up will let you use ssh, scp, etc from your command line.

null check in jsf expression language

Use empty (it checks both nullness and emptiness) and group the nested ternary expression by parentheses (EL is in certain implementations/versions namely somewhat problematic with nested ternary expressions). Thus, so:

styleClass="#{empty obj.validationErrorMap ? ' ' :  
 (obj.validationErrorMap.contains('key') ? 'highlight_field' : 'highlight_row')}"

If still in vain (I would then check JBoss EL configs), use the "normal" EL approach:

styleClass="#{empty obj.validationErrorMap ? ' ' :  
 (obj.validationErrorMap['key'] ne null ? 'highlight_field' : 'highlight_row')}"

Update: as per the comments, the Map turns out to actually be a List (please work on your naming conventions). To check if a List contains an item the "normal" EL way, use JSTL fn:contains (although not explicitly documented, it works for List as well).

styleClass="#{empty obj.validationErrorMap ? ' ' :  
 (fn:contains(obj.validationErrorMap, 'key') ? 'highlight_field' : 'highlight_row')}"