Programs & Examples On #Websharper

The web platform based on an F# to JavaScript compiler.

How to listen for 'props' changes

@JoeSchr has an answer. Here is another way to do if you don't want deep: true

 mounted() {
    this.yourMethod();
    // re-render any time a prop changes
    Object.keys(this.$options.props).forEach(key => {
      this.$watch(key, this.yourMethod);
    });
  },

Python, how to check if a result set is empty?

cursor.rowcount will usually be set to 0.

If, however, you are running a statement that would never return a result set (such as INSERT without RETURNING, or SELECT ... INTO), then you do not need to call .fetchall(); there won't be a result set for such statements. Calling .execute() is enough to run the statement.


Note that database adapters are also allowed to set the rowcount to -1 if the database adapter can't determine the exact affected count. See the PEP 249 Cursor.rowcount specification:

The attribute is -1 in case no .execute*() has been performed on the cursor or the rowcount of the last operation is cannot be determined by the interface.

The sqlite3 library is prone to doing this. In all such cases, if you must know the affected rowcount up front, execute a COUNT() select in the same transaction first.

How to run sql script using SQL Server Management Studio?

This website has a concise tutorial on how to use SQL Server Management Studio. As you will see you can open a "Query Window", paste your script and run it. It does not allow you to execute scripts by using the file path. However, you can do this easily by using the command line (cmd.exe):

sqlcmd -S .\SQLExpress -i SqlScript.sql

Where SqlScript.sql is the script file name located at the current directory. See this Microsoft page for more examples

PHP foreach with Nested Array?

Both syntaxes are correct. But the result would be Array. You probably want to do something like this:

foreach ($tmpArray[1] as $value) {
  echo $value[0];
  foreach($value[1] as $val){
    echo $val;
  }
}

This will print out the string "two" ($value[0]) and the integers 4, 5 and 6 from the array ($value[1]).

How do you use Intent.FLAG_ACTIVITY_CLEAR_TOP to clear the Activity Stack?

I use three flags to resolve the problem:

intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|
                Intent.FLAG_ACTIVITY_CLEAR_TASK | 
                Intent.FLAG_ACTIVITY_NEW_TASK);

List passed by ref - help me explain this behaviour

Use the ref keyword.

Look at the definitive reference here to understand passing parameters.
To be specific, look at this, to understand the behavior of the code.

EDIT: Sort works on the same reference (that is passed by value) and hence the values are ordered. However, assigning a new instance to the parameter won't work because parameter is passed by value, unless you put ref.

Putting ref lets you change the pointer to the reference to a new instance of List in your case. Without ref, you can work on the existing parameter, but can't make it point to something else.

How to clear react-native cache?

For React Native Init approach (without expo) use:

npm start -- --reset-cache

PHP Fatal error: Class 'PDO' not found

you can just find-out loaded config file by executing below command,

 php -i | grep 'php.ini'

Then add below lines to correct php.ini file

extension=pdo.so
extension=pdo_sqlite.so
extension=pdo_mysql.so
extension=sqlite.so

Then restart web server,

service httpd restart

VB.Net Properties - Public Get, Private Set

I'm not sure what the minimum required version of Visual Studio is, but in VS2015 you can use

Public ReadOnly Property Name As String

It is read-only for public access but can be privately modified using _Name

Applying .gitignore to committed files

Old question, but some of us are in git-posh (powershell). This is the solution for that:

git ls-files -ci --exclude-standard | foreach { git rm --cached $_ }

How to change Hash values?

I do something like this:

new_hash = Hash[*original_hash.collect{|key,value| [key,value + 1]}.flatten]

This provides you with the facilities to transform the key or value via any expression also (and it's non-destructive, of course).

Making a Sass mixin with optional arguments

You can always assign null to your optional arguments. Here is a simple fix

@mixin box-shadow($top, $left, $blur, $color, $inset:null) { //assigning null to inset value makes it optional
    -webkit-box-shadow: $top $left $blur $color $inset;
    -moz-box-shadow: $top $left $blur $color $inset;
    box-shadow: $top $left $blur $color $inset;
}

What Does 'zoom' do in CSS?

As Joshua M pointed out, the zoom function isn't supported only in Firefox, but you can simply fix this as shown:

div.zoom {
  zoom: 2; /* all browsers */
 -moz-transform: scale(2);  /* Firefox */
}

How to run Java program in terminal with external library JAR

You can do :

1) javac -cp /path/to/jar/file Myprogram.java

2) java -cp .:/path/to/jar/file Myprogram

So, lets suppose your current working directory in terminal is src/Report/

javac -cp src/external/myfile.jar Reporter.java

java -cp .:src/external/myfile.jar Reporter

Take a look here to setup Classpath

Create table variable in MySQL

If you don't want to store table in database then @Evan Todd already has been provided temporary table solution.

But if you need that table for other users and want to store in db then you can use below procedure.

Create below ‘stored procedure’:

————————————

DELIMITER $$

USE `test`$$

DROP PROCEDURE IF EXISTS `sp_variable_table`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `sp_variable_table`()
BEGIN

SELECT CONCAT(‘zafar_’,REPLACE(TIME(NOW()),’:',’_')) INTO @tbl;

SET @str=CONCAT(“create table “,@tbl,” (pbirfnum BIGINT(20) NOT NULL DEFAULT ’0', paymentModes TEXT ,paymentmodeDetails TEXT ,shippingCharges TEXT ,shippingDetails TEXT ,hypenedSkuCodes TEXT ,skuCodes TEXT ,itemDetails TEXT ,colorDesc TEXT ,size TEXT ,atmDesc TEXT ,promotional TEXT ,productSeqNumber VARCHAR(16) DEFAULT NULL,entity TEXT ,entityDetails TEXT ,kmtnmt TEXT ,rating BIGINT(1) DEFAULT NULL,discount DECIMAL(15,0) DEFAULT NULL,itemStockDetails VARCHAR(38) NOT NULL DEFAULT ”) ENGINE=INNODB DEFAULT CHARSET=utf8");
PREPARE stmt FROM @str;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

SELECT ‘Table has been created’;
END$$

DELIMITER ;

———————————————–

Now you can execute this procedure to create a variable name table as per below-

call sp_variable_table();

You can check new table after executing below command-

use test;show tables like ‘%zafar%’; — test is here ‘database’ name.

You can also check more details at below path-

http://mydbsolutions.in/how-can-create-a-table-with-variable-name/

Flutter: Run method on Widget build complete

If you are looking for ReactNative's componentDidMount equivalent, Flutter has it. It's not that simple but it's working just the same way. In Flutter, Widgets do not handle their events directly. Instead they use their State object to do that.

class MyWidget extends StatefulWidget{

  @override
  State<StatefulWidget> createState() => MyState(this);

  Widget build(BuildContext context){...} //build layout here

  void onLoad(BuildContext context){...} //callback when layout build done
}

class MyState extends State<MyWidget>{

  MyWidget widget;

  MyState(this.widget);

  @override
  Widget build(BuildContext context) => widget.build(context);

  @override
  void initState() => widget.onLoad(context);
}

State.initState immediately will be called once upon screen has finishes rendering the layout. And will never again be called even on hot reload if you're in debug mode, until explicitly reaches time to do so.

GET URL parameter in PHP

Please post your code,

<?php
    echo $_GET['link'];
?>

or

<?php
    echo $_REQUEST['link'];
?>

do work...

What to do about Eclipse's "No repository found containing: ..." error messages?

I got this error (September 2020) during an automatic upgrade.

The solution was to add:

http://download.eclipse.org/releases/2020-09

to the list of Available Software Sites.

I also disabled:

http://download.eclipse.org/eclipse/updates/4.15

and several more with release numbers earlier than 4.15, but I don't think that was the important part.

How can I extract a predetermined range of lines from a text file on Unix?

I was about to post the head/tail trick, but actually I'd probably just fire up emacs. ;-)

  1. esc-x goto-line ret 16224
  2. mark (ctrl-space)
  3. esc-x goto-line ret 16482
  4. esc-w

open the new output file, ctl-y save

Let's me see what's happening.

How to extract extension from filename string in Javascript?

This is the solution if your file has more . (dots) in the name.

<script type="text/javascript">var x = "file1.asdf.txt";
var y = x.split(".");
alert(y[(y.length)-1]);</script>

Extracting first n columns of a numpy matrix

I know this is quite an old question -

A = [[1, 2, 3],
     [4, 5, 6],
     [7, 8, 9]]

Let's say, you want to extract the first 2 rows and first 3 columns

A_NEW = A[0:2, 0:3]
A_NEW = [[1, 2, 3],
         [4, 5, 6]]

Understanding the syntax

A_NEW = A[start_index_row : stop_index_row, 
          start_index_column : stop_index_column)]

If one wants row 2 and column 2 and 3

A_NEW = A[1:2, 1:3]

Reference the numpy indexing and slicing article - Indexing & Slicing

Find and Replace string in all files recursive using grep and sed

grep -rl $oldstring . | xargs sed -i "s/$oldstring/$newstring/g"

Getting data posted in between two dates

May this helpful to you.... With Join of Three Tables

public function get_details_beetween_dates()
    {
        $from = $this->input->post('fromdate');
        $to = $this->input->post('todate');

        $this->db->select('users.first_name, users.last_name, users.email, groups.name as designation, dailyinfo.amount as Total_Fine, dailyinfo.date as Date_of_Fine, dailyinfo.desc as Description')
                    ->from('users')
                    ->where('dailyinfo.date >= ',$from)
                    ->where('dailyinfo.date <= ',$to)
                    ->join('users_groups','users.id = users_groups.user_id')
                    ->join('dailyinfo','users.id = dailyinfo.userid')
                    ->join('groups','groups.id = users_groups.group_id');

        /*
        $this->db->select('date, amount, desc')
                 ->from('dailyinfo')
                 ->where('dailyinfo.date >= ',$from)
                 ->where('dailyinfo.date <= ',$to);
        */

        $q = $this->db->get();

        $array['userDetails'] = $q->result();
        return $array;
    }

Unix epoch time to Java Date object

Better yet, use JodaTime. Much easier to parse strings and into strings. Is thread safe as well. Worth the time it will take you to implement it.

How do I find the last column with data?

Try using the code after you active the sheet:

Dim J as integer
J = ActiveSheet.UsedRange.SpecialCells(xlCellTypeLastCell).Row

If you use Cells.SpecialCells(xlCellTypeLastCell).Row only, the problem will be that the xlCellTypeLastCell information will not be updated unless one do a "Save file" action. But use UsedRange will always update the information in realtime.

How can I load storyboard programmatically from class?

Swift 3

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "viewController")
self.navigationController!.pushViewController(vc, animated: true)

Swift 2

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("viewController")
self.navigationController!.pushViewController(vc, animated: true)

Prerequisite

Assign a Storyboard ID to your view controller.

Storyboard ID

IB > Show the Identity inspector > Identity > Storyboard ID

Swift (legacy)

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("viewController") as? UIViewController
self.navigationController!.pushViewController(vc!, animated: true)

Edit: Swift 2 suggested in a comment by Fred A.

if you want to use without any navigationController you have to use like following :

    let Storyboard  = UIStoryboard(name: "Main", bundle: nil)
    let vc = Storyboard.instantiateViewController(withIdentifier: "viewController")
    present(vc , animated: true , completion: nil)

How do I remove javascript validation from my eclipse project?

In addition, if you are using Tern eclipse IDE or IBM Node.js Tools for Eclipse, you may need to disable JSHint and other libraries that you don't want.

To disable this, Project Properties > Tern > Modules > JSHint or any other library that you don't want. enter image description here

Why is a primary-foreign key relation required when we can join without it?

You don't need a FK, you can join arbitrary columns.

But having a foreign key ensures that the join will actually succeed in finding something.

Foreign key give you certain guarantees that would be extremely difficult and error prone to implement otherwise.

For example, if you don't have a foreign key, you might insert a detail record in the system and just after you checked that the matching master record is present somebody else deletes it. So in order to prevent this you need to lock the master table, when ever you modify the detail table (and vice versa). If you don't need/want that guarantee, screw the FKs.

Depending on your RDBMS a foreign key also might improve performance of select (but also degrades performance of updates, inserts and deletes)

How to view DLL functions?

For .NET DLLs you can use ildasm

Is Xamarin free in Visual Studio 2015?

Visual studio community edition is bundled with xamarin and which is free as well.

List of installed gems?

Both

gem query --local

and

 ruby -S gem list --local

list 69 entries

While

ruby -e 'puts Gem::Specification.all_names'

gives me 82

I used wc -l to get the numbers. Not sure if that is the right way to check. Tried to redirect the output to text files and diff'ed but that didn't help - will need to compare manually one by one.

Why does JPA have a @Transient annotation?

In laymen's terms, if you use the @Transient annotation on an attribute of an entity: this attribute will be singled out and will not be saved to the database. The rest of the attribute of the object within the entity will still be saved.

example:

Im saving the Object to the database using the jpa repository built in save method as so:

userRoleJoinRepository.save(user2);

How can we run a test method with multiple parameters in MSTest?

I couldn't get The DataRowAttribute to work in Visual Studio 2015, and this is what I ended up with:

[TestClass]
public class Tests
{
    private Foo _toTest;

    [TestInitialize]
    public void Setup()
    {
        this._toTest = new Foo();
    }

    [TestMethod]
    public void ATest()
    {
        this.Perform_ATest(1, 1, 2);
        this.Setup();

        this.Perform_ATest(100, 200, 300);
        this.Setup();

        this.Perform_ATest(817001, 212, 817213);
        this.Setup();
    }

    private void Perform_ATest(int a, int b, int expected)
    {
        // Obviously this would be way more complex...

        Assert.IsTrue(this._toTest.Add(a,b) == expected);
    }
}

public class Foo
{
    public int Add(int a, int b)
    {
        return a + b;
    }
}

The real solution here is to just use NUnit (unless you're stuck in MSTest like I am in this particular instance).

Online PHP syntax checker / validator

I found this for online php validation:-

http://www.icosaedro.it/phplint/phplint-on-line.html

Hope this helps.

Only variable references should be returned by reference - Codeigniter

this has been modified in codeigniter 2.2.1...usually not best practice to modify core files, I would always check for updates and 2.2.1 came out in Jan 2015

You have not accepted the license agreements of the following SDK components

Go to your $ANDROID_HOME/tools/bin and fire the cmd

./sdkmanager --licenses

Accept All licenses listed there.

After this just go to the licenses folder in sdk and check that it's having these five files:

android-sdk-license, android-googletv-license, android-sdk-preview-license, google-gdk-license, mips-android-sysimage-license

Give a retry and build again, still jenkins giving 'licenses not accepted' then you have to give full permission to your 'sdk' directory and all it's parent directories. Here is the command:

sudo chmod -R 777 /opt/

If you having sdk in /opt/ directory.

How to raise a ValueError?

>>> response='bababa'
...  if "K" in response.text:
...     raise ValueError("Not found")

Read only file system on Android

I checked with emulator and following worked.

  1. adb reboot
  2. adb root && adb remount && adb push ~/Desktop/hosts /system/etc/hosts

As mentioned above as well, execute second step in single shot.

"Python version 2.7 required, which was not found in the registry" error when attempting to install netCDF4 on Windows 8

I had the same issue when using an .exe to install a Python package (because I use Anaconda and it didn't add Python to the registry). I fixed the problem by running this script:

#
# script to register Python 2.0 or later for use with 
# Python extensions that require Python registry settings
#
# written by Joakim Loew for Secret Labs AB / PythonWare
#
# source:
# http://www.pythonware.com/products/works/articles/regpy20.htm
#
# modified by Valentine Gogichashvili as described in http://www.mail-archive.com/[email protected]/msg10512.html

import sys

from _winreg import *

# tweak as necessary
version = sys.version[:3]
installpath = sys.prefix

regpath = "SOFTWARE\\Python\\Pythoncore\\%s\\" % (version)
installkey = "InstallPath"
pythonkey = "PythonPath"
pythonpath = "%s;%s\\Lib\\;%s\\DLLs\\" % (
    installpath, installpath, installpath
)

def RegisterPy():
    try:
        reg = OpenKey(HKEY_CURRENT_USER, regpath)
    except EnvironmentError as e:
        try:
            reg = CreateKey(HKEY_CURRENT_USER, regpath)
            SetValue(reg, installkey, REG_SZ, installpath)
            SetValue(reg, pythonkey, REG_SZ, pythonpath)
            CloseKey(reg)
        except:
            print "*** Unable to register!"
            return
        print "--- Python", version, "is now registered!"
        return
    if (QueryValue(reg, installkey) == installpath and
        QueryValue(reg, pythonkey) == pythonpath):
        CloseKey(reg)
        print "=== Python", version, "is already registered!"
        return
    CloseKey(reg)
    print "*** Unable to register!"
    print "*** You probably have another Python installation!"

if __name__ == "__main__":
    RegisterPy()

How can I insert new line/carriage returns into an element.textContent?

I found that inserting \\n works. I.e., you escape the escaped new line character

How to find where javaw.exe is installed?

Try this

for %i in (javaw.exe) do @echo. %~$PATH:i

How do we use runOnUiThread in Android?

We use Worker Thread to make Apps smoother and avoid ANR's. We may need to update UI after the heavy process in worker Tread. The UI can only be updated from UI Thread. In such cases, we use Handler or runOnUiThread both have a Runnable run method that executes in UI Thread. The onClick method runs in UI thread so don't need to use runOnUiThread here.

Using Kotlin

While in Activity,

this.runOnUiThread {
      // Do stuff
}

From Fragment,

activity?.runOnUiThread {
      // Do stuff
}

Using Java,

this.runOnUiThread(new Runnable() {
     void run() {
         // Do stuff
     }
});

How to solve "Kernel panic - not syncing - Attempted to kill init" -- without erasing any user data

At grub screen goto boot in recovery.

As booting hold ESC

It should take you into a gui menu. Open command and fix selinux.

Also I suggest run the clean broken packages

JavaScript replace \n with <br />

Use a regular expression for .replace().:

messagetoSend = messagetoSend.replace(/\n/g, "<br />");

If those linebreaks were made by windows-encoding, you will also have to replace the carriage return.

messagetoSend = messagetoSend.replace(/\r\n/g, "<br />");

Radio Buttons ng-checked with ng-model

Please explain why same ng-model is used? And what value is passed through ng- model and how it is passed? To be more specific, if I use console.log(color) what would be the output?

possibly undefined macro: AC_MSG_ERROR

I had the same problem on Ubuntu (error: possibly undefined macro: AC_MSG_ERROR) but the answers above didn't work for me. I found the solution here

That did the trick:

$ LANG=C LC_CTYPE=C ./autogen.sh

Two dimensional array in python

the above method did not work for me for a for loop, where I wanted to transfer data from a 2D array to a new array under an if the condition. This method would work

a_2d_list = [[1, 2], [3, 4]]
a_2d_list.append([5, 6])
print(a_2d_list)

OUTPUT - [[1, 2], [3, 4], [5, 6]]

Sniffing/logging your own Android Bluetooth traffic

Also, this might help finding the actual location the btsnoop_hci.log is being saved:

adb shell "cat /etc/bluetooth/bt_stack.conf | grep FileName"

Save a list to a .txt file

You can use inbuilt library pickle

This library allows you to save any object in python to a file

This library will maintain the format as well

import pickle
with open('/content/list_1.txt', 'wb') as fp:
    pickle.dump(list_1, fp)

you can also read the list back as an object using same library

with open ('/content/list_1.txt', 'rb') as fp:
    list_1 = pickle.load(fp)

reference : Writing a list to a file with Python

How to wait until an element is present in Selenium?

You need to call ignoring with exception to ignore while the WebDriver will wait.

FluentWait<WebDriver> fluentWait = new FluentWait<>(driver)
        .withTimeout(30, TimeUnit.SECONDS)
        .pollingEvery(200, TimeUnit.MILLISECONDS)
        .ignoring(NoSuchElementException.class);

See the documentation of FluentWait for more info. But beware that this condition is already implemented in ExpectedConditions so you should use

WebElement element = (new WebDriverWait(driver, 10))
   .until(ExpectedConditions.elementToBeClickable(By.id("someid")));

*Update for newer versions of Selenium:

withTimeout(long, TimeUnit) has become withTimeout(Duration)
pollingEvery(long, TimeUnit) has become pollingEvery(Duration)

So the code will look as such:

FluentWait<WebDriver> fluentWait = new FluentWait<>(driver)
        .withTimeout(Duration.ofSeconds(30)
        .pollingEvery(Duration.ofMillis(200)
        .ignoring(NoSuchElementException.class);

Basic tutorial for waiting can be found here.

How to abort an interactive rebase if --abort doesn't work?

Try to follow the advice you see on the screen, and first reset your master's HEAD to the commit it expects.

git update-ref refs/heads/master b918ac16a33881ce00799bea63d9c23bf7022d67

Then, abort the rebase again.

Android: ProgressDialog.show() crashes with getApplicationContext

I have implemented Alert Dialog for exception throwing on to the current activitty view.Whenever I had given like this

AlertDialog.Builder builder = new AlertDialog.Builder(context);

Given same Window Exception.I write code for alert out of onCreate().So simple I used context = this; after setContentView() statement in onCreate() method.Taken context variable as global like Context context;

Code sample is

static Context context;

 public void onCreate(Bundle savedInstanceState)  { 
        super.onCreate(savedInstanceState); 


        setContentView(R.layout.network); 
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

        context = this;
.......

Alert Method Sample is

private void alertException(String execMsg){
        Log.i(TAG,"in alertException()..."+context);
        Log.e(TAG,"Exception :"+execMsg);
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
.......

It works fine for me.Actually I searched for this error on StackOverflow I found this query.After reading all responses of this post, I tried this way so It works .I thought this is a simple solution for overcome the exception.

Thanks, Rajendar

How to convert UTF-8 byte[] to string?

In adition to the selected answer, if you're using .NET35 or .NET35 CE, you have to specify the index of the first byte to decode, and the number of bytes to decode:

string result = System.Text.Encoding.UTF8.GetString(byteArray,0,byteArray.Length);

How to "test" NoneType in python?

It can also be done with isinstance as per Alex Hall's answer :

>>> NoneType = type(None)
>>> x = None
>>> type(x) == NoneType
True
>>> isinstance(x, NoneType)
True

isinstance is also intuitive but there is the complication that it requires the line

NoneType = type(None)

which isn't needed for types like int and float.

PostgreSQL: ERROR: operator does not exist: integer = character varying

I think it is telling you exactly what is wrong. You cannot compare an integer with a varchar. PostgreSQL is strict and does not do any magic typecasting for you. I'm guessing SQLServer does typecasting automagically (which is a bad thing).

If you want to compare these two different beasts, you will have to cast one to the other using the casting syntax ::.

Something along these lines:

create view view1
as 
select table1.col1,table2.col1,table3.col3
from table1 
inner join
table2 
inner join 
table3
on 
table1.col4::varchar = table2.col5
/* Here col4 of table1 is of "integer" type and col5 of table2 is of type "varchar" */
/* ERROR: operator does not exist: integer = character varying */
....;

Notice the varchar typecasting on the table1.col4.

Also note that typecasting might possibly render your index on that column unusable and has a performance penalty, which is pretty bad. An even better solution would be to see if you can permanently change one of the two column types to match the other one. Literately change your database design.

Or you could create a index on the casted values by using a custom, immutable function which casts the values on the column. But this too may prove suboptimal (but better than live casting).

Process all arguments except the first one (in a bash script)

http://wiki.bash-hackers.org/scripting/posparams

It explains the use of shift (if you want to discard the first N parameters) and then implementing Mass Usage

How do I install Keras and Theano in Anaconda Python on Windows?

Anaconda with Windows

  • Run anaconda prompt with administrator privilages
  • conda update conda
  • conda update --all
  • conda install mingw libpython
  • conda install theano

After conda commands it's required to accept process - Proceed ([y]/n)?

how to use python2.7 pip instead of default pip

An alternative is to call the pip module by using python2.7, as below:

python2.7 -m pip <commands>

For example, you could run python2.7 -m pip install <package> to install your favorite python modules. Here is a reference: https://stackoverflow.com/a/50017310/4256346.

In case the pip module has not yet been installed for this version of python, you can run the following:

python2.7 -m ensurepip

Running this command will "bootstrap the pip installer". Note that running this may require administrative privileges (i.e. sudo). Here is a reference: https://docs.python.org/2.7/library/ensurepip.html and another reference https://stackoverflow.com/a/46631019/4256346.

MySQL CONCAT returns NULL if any field contain NULL

Use CONCAT_WS instead:

CONCAT_WS() does not skip empty strings. However, it does skip any NULL values after the separator argument.

SELECT CONCAT_WS('-',`affiliate_name`,`model`,`ip`,`os_type`,`os_version`) AS device_name FROM devices

JRE 1.7 - java version - returns: java/lang/NoClassDefFoundError: java/lang/Object

Quick Solution for impatient people ;) On Windows machines, try this: Go to C:\Windows\System32 directory and delete java.exe (or rename it to something like java.exe.old).

Since at least 1.6, there should not be a java.exe in the Windows directory. If there is, it's a leftover from something.

A bit more reading:

I'm really suprised that a question from 2012 doesn't have an approved answer yet and I've actually encountered the same issue in 2015 on my Win 7 32-Bit OS!

So what did happen?

Basically, everything was working fine, I downloaded H2 database and when I tried to start H2 Console (Command Line) I got:

Error occurred during initialization of VM
java/lang/NoClassDefFoundError: java/lang/Object

I found this question and I was able to confirm the same symptoms:

JAVA_HOME is set correctly:

echo %JAVA_HOME%
C:\Program Files\Java\jdk1.6.0_26

java -version fails, while java --fullversion works fine:

java -fullversion
java full version "1.6.0_45-b06"

SOLUTION: Go to C:\Windows\System32 directory and delete (I actually renamed) java.exe file!!!!

Now, I get:

java -version
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) Client VM (build 20.1-b02, mixed mode, sharing)

and H2 Console (Command Line) works fine as well!

Credits go to the last post in this forum: https://bukkit.org/threads/java-lang-noclassdeffounderror-java-lang-object.70450/

How to compile a 32-bit binary on a 64-bit linux machine with gcc/cmake

For any complex application, I suggest to use an lxc container. lxc containers are 'something in the middle between a chroot on steroids and a full fledged virtual machine'.

For example, here's a way to build 32-bit wine using lxc on an Ubuntu Trusty system:

sudo apt-get install lxc lxc-templates
sudo lxc-create -t ubuntu -n my32bitbox -- --bindhome $LOGNAME -a i386 --release trusty
sudo lxc-start -n my32bitbox
# login as yourself
sudo sh -c "sed s/deb/deb-src/ /etc/apt/sources.list >> /etc/apt/sources.list"
sudo apt-get install devscripts
sudo apt-get build-dep wine1.7
apt-get source wine1.7
cd wine1.7-*
debuild -eDEB_BUILD_OPTIONS="parallel=8" -i -us -uc -b
shutdown -h now   # to exit the container

Here is the wiki page about how to build 32-bit wine on a 64-bit host using lxc.

How to specify a port to run a create-react-app based project?

This works on both Windows and Linux (Doesn't work on Mac)

package.json

"scripts": {
    "start": "(set PORT=3006 || export PORT=3006) && react-scripts start"
    ...
}

but you propably prefer to create .env with PORT=3006 written inside it

Getting request URL in a servlet

The getRequestURL() omits the port when it is 80 while the scheme is http, or when it is 443 while the scheme is https.

So, just use getRequestURL() if all you want is obtaining the entire URL. This does however not include the GET query string. You may want to construct it as follows then:

StringBuffer requestURL = request.getRequestURL();
if (request.getQueryString() != null) {
    requestURL.append("?").append(request.getQueryString());
}
String completeURL = requestURL.toString();

How to get the first day of the current week and month?

public static void main(String[] args) {
    System.out.println(getMonthlyEpochList(1498867199L,12,"Monthly"));

}

public static Map<String,String> getMonthlyEpochList(Long currentEpoch, int noOfTerms, String timeMode) {
    Map<String,String> map = new LinkedHashMap<String,String>();
    int month = 0;
    while(noOfTerms != 0) {
        Calendar calendar = Calendar.getInstance();         
        calendar.add(Calendar.MONTH, month);
        calendar.set(Calendar.DATE, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
        Date monthFirstDay = calendar.getTime();
        calendar.set(Calendar.DATE, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
        Date monthLastDay = calendar.getTime();
        map.put(getMMYY(monthFirstDay.getTime()), monthFirstDay + ":" +monthLastDay);
        month--;
        noOfTerms--;
    }
    return map;     
}

Tensorflow set CUDA_VISIBLE_DEVICES within jupyter

You can do it faster without any imports just by using magics:

%env CUDA_DEVICE_ORDER=PCI_BUS_ID
%env CUDA_VISIBLE_DEVICES=0

Notice that all env variable are strings, so no need to use ". You can verify that env-variable is set up by running: %env <name_of_var>. Or check all of them with %env.

datetime.parse and making it work with a specific format

Thanks for the tip, i used this to get my date "20071122" parsed, I needed to add datetimestyles, I used none and it worked:

DateTime dt = DateTime.MinValue;

DateTime.TryParseExact("20071122", "yyyyMMdd", null,System.Globalization.DateTimeStyles.None, out dt);

How to print the current Stack Trace in .NET without any exception?

There are two ways to do this. The System.Diagnostics.StackTrace() will give you a stack trace for the current thread. If you have a reference to a Thread instance, you can get the stack trace for that via the overloaded version of StackTrace().

You may also want to check out Stack Overflow question How to get non-current thread's stacktrace?.

Clear variable in python

The del keyword would do.

>>> a=1
>>> a
1
>>> del a
>>> a
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'a' is not defined

But in this case I vote for self.left = None

Mysql: Select rows from a table that are not in another

This worked for me in Oracle:

SELECT a.* 
    FROM tbl1 a 
MINUS 
SELECT b.* 
    FROM tbl2 b;

Change the Arrow buttons in Slick slider

You can easily create your own style of arrow with the .slick-next:before and the .slick-prev:after pseudo-classes.

Here's an example:

.slick-prev:before {
  content: "<";
  color: red;
  font-size: 30px;
}

.slick-next:before {
  content: ">";
  color: red;
  font-size: 30px;
}

How to fix the session_register() deprecated issue?

To complement Felix Kling's answer, I was studying a codebase that used to have the following code:

if (is_array($start_vars)) {
    foreach ($start_vars as $var) {
        session_register($var);
    }
} else if (!(empty($start_vars))) {
    session_register($start_vars);
}

In order to not use session_register they made the following adjustments:

if (is_array($start_vars)) {
    foreach ($start_vars as $var) {
        $_SESSION[$var] =  $GLOBALS[$var];
    }
} else if (!(empty($start_vars))) {
    $_SESSION[$start_vars] =  $GLOBALS[$start_vars];
}

How To Inject AuthenticationManager using Java Configuration in a Custom Filter

Override method authenticationManagerBean in WebSecurityConfigurerAdapter to expose the AuthenticationManager built using configure(AuthenticationManagerBuilder) as a Spring bean:

For example:

   @Bean(name = BeanIds.AUTHENTICATION_MANAGER)
   @Override
   public AuthenticationManager authenticationManagerBean() throws Exception {
       return super.authenticationManagerBean();
   }

Tensorflow: how to save/restore a model?

For tensorflow-2.0

it's very simple.

import tensorflow as tf

SAVE

model.save("model_name")

RESTORE

model = tf.keras.models.load_model('model_name')

Getting current date and time in JavaScript

function display_c(){   
    var refresh = 1000; // Refresh rate in milli seconds    
    mytime = setTimeout('display_ct()', refresh)    
}

function display_ct() {

    var strcount    
    var currentdate = new Date();

    document.getElementById('ct').innerHTML = currentdate.toDateString() + " " + currentdate.getHours() + ":" + currentdate.getMinutes() + ":" + currentdate.getSeconds();

    tt = display_c();   
}


id = 'ct'     // Replace in Your id

onload = "display_ct();"     // Type inside a Body Tag

How to insert data into elasticsearch

You have to install the curl binary in your PC first. You can download it from here.

After that unzip it into a folder. Lets say C:\curl. In that folder you'll find curl.exe file with several .dll files.

Now open a command prompt by typing cmd from the start menu. And type cd c:\curl on there and it will take you to the curl folder. Now execute the curl command that you have.

One thing, windows doesn't support single quote around around the fields. So you have to use double quotes. For example I have converted your curl command like appropriate one.

curl -H "Content-Type: application/json" -XPOST "http://localhost:9200/indexname/typename/optionalUniqueId" -d "{ \"field\" : \"value\"}"

How do I check if an HTML element is empty using jQuery?

Here's a jQuery filter based on https://stackoverflow.com/a/6813294/698289

$.extend($.expr[':'], {
  trimmedEmpty: function(el) {
    return !$.trim($(el).html());
  }
});

S3 Static Website Hosting Route All Paths to Index.html

The easiest solution to make Angular 2+ application served from Amazon S3 and direct URLs working is to specify index.html both as Index and Error documents in S3 bucket configuration.

enter image description here

Syntax for async arrow function

You may also do:

 YourAsyncFunctionName = async (value) => {

    /* Code goes here */

}

Android: textview hyperlink

Very simple way to do this---

In your Activity--

 TextView tv = (TextView) findViewById(R.id.site);
 tv.setText(Html.fromHtml("<a href=http://www.stackoverflow.com> STACK OVERFLOW "));
 tv.setMovementMethod(LinkMovementMethod.getInstance());

Then you will get just the Tag, not the whole link..

Hope it will help you...

How can I work with command line on synology?

You can use your favourite telnet (not recommended) or ssh (recommended) application to connect to your Synology box and use it as a terminal.

  1. Enable the command line interface (CLI) from the Network Services
  2. Define the protocol and the user and make sure the user has password set
  3. Access the CLI

If you need more detailed instruction read https://www.synology.com/en-global/knowledgebase/DSM/help/DSM/AdminCenter/system_terminal

Saving the PuTTY session logging

It works fine for me, but it's a little tricky :)

  • First open the PuTTY configuration.
  • Select the session (right part of the window, Saved Sessions)
  • Click Load (now you have loaded Host Name, Port and Connection type)
  • Then click Logging (under Session on the left)
  • Change whatever settings you want
  • Go back to Session window and click the Save button

Now you have settings for this session set (every time you load session it will be logged).

How does numpy.histogram() work?

A bin is range that represents the width of a single bar of the histogram along the X-axis. You could also call this the interval. (Wikipedia defines them more formally as "disjoint categories".)

The Numpy histogram function doesn't draw the histogram, but it computes the occurrences of input data that fall within each bin, which in turns determines the area (not necessarily the height if the bins aren't of equal width) of each bar.

In this example:

 np.histogram([1, 2, 1], bins=[0, 1, 2, 3])

There are 3 bins, for values ranging from 0 to 1 (excl 1.), 1 to 2 (excl. 2) and 2 to 3 (incl. 3), respectively. The way Numpy defines these bins if by giving a list of delimiters ([0, 1, 2, 3]) in this example, although it also returns the bins in the results, since it can choose them automatically from the input, if none are specified. If bins=5, for example, it will use 5 bins of equal width spread between the minimum input value and the maximum input value.

The input values are 1, 2 and 1. Therefore, bin "1 to 2" contains two occurrences (the two 1 values), and bin "2 to 3" contains one occurrence (the 2). These results are in the first item in the returned tuple: array([0, 2, 1]).

Since the bins here are of equal width, you can use the number of occurrences for the height of each bar. When drawn, you would have:

  • a bar of height 0 for range/bin [0,1] on the X-axis,
  • a bar of height 2 for range/bin [1,2],
  • a bar of height 1 for range/bin [2,3].

You can plot this directly with Matplotlib (its hist function also returns the bins and the values):

>>> import matplotlib.pyplot as plt
>>> plt.hist([1, 2, 1], bins=[0, 1, 2, 3])
(array([0, 2, 1]), array([0, 1, 2, 3]), <a list of 3 Patch objects>)
>>> plt.show()

enter image description here

How do I convert from int to String?

Normal ways would be Integer.toString(i) or String.valueOf(i).

The concatenation will work, but it is unconventional and could be a bad smell as it suggests the author doesn't know about the two methods above (what else might they not know?).

Java has special support for the + operator when used with strings (see the documentation) which translates the code you posted into:

StringBuilder sb = new StringBuilder();
sb.append("");
sb.append(i);
String strI = sb.toString();

at compile-time. It's slightly less efficient (sb.append() ends up calling Integer.getChars(), which is what Integer.toString() would've done anyway), but it works.

To answer Grodriguez's comment: ** No, the compiler doesn't optimise out the empty string in this case - look:

simon@lucifer:~$ cat TestClass.java
public class TestClass {
  public static void main(String[] args) {
    int i = 5;
    String strI = "" + i;
  }
}
simon@lucifer:~$ javac TestClass.java && javap -c TestClass
Compiled from "TestClass.java"
public class TestClass extends java.lang.Object{
public TestClass();
  Code:
   0:    aload_0
   1:    invokespecial    #1; //Method java/lang/Object."<init>":()V
   4:    return

public static void main(java.lang.String[]);
  Code:
   0:    iconst_5
   1:    istore_1

Initialise the StringBuilder:

   2:    new    #2; //class java/lang/StringBuilder
   5:    dup
   6:    invokespecial    #3; //Method java/lang/StringBuilder."<init>":()V

Append the empty string:

   9:    ldc    #4; //String
   11:    invokevirtual    #5; //Method java/lang/StringBuilder.append:
(Ljava/lang/String;)Ljava/lang/StringBuilder;

Append the integer:

   14:    iload_1
   15:    invokevirtual    #6; //Method java/lang/StringBuilder.append:
(I)Ljava/lang/StringBuilder;

Extract the final string:

   18:    invokevirtual    #7; //Method java/lang/StringBuilder.toString:
()Ljava/lang/String;
   21:    astore_2
   22:    return
}

There's a proposal and ongoing work to change this behaviour, targetted for JDK 9.

Official reasons for "Software caused connection abort: socket write error"

I have seen this most often when a corporate firewall on a workstation/laptop gets in the way, it kills the connection.

eg. I have a server process and a client process on the same machine. The server is listening on all interfaces (0.0.0.0) and the client attempts a connection to the public/home interface (note not the loopback interface 127.0.0.1).

If the machine is has its network disconnected (eg wifi turned off) then the connection is formed. If the machine is connected to the corporate network (directly or vpn) then the connection is formed.

However, if the machine is connected to a public wifi (or home network) then the firewall kicks in an kills the connection. In this situation connecting the client to the loopback interface works fine, just not to the home/public interface.

Hope this helps.

Error: Microsoft Visual C++ 10.0 is required (Unable to find vcvarsall.bat) when running Python script

Python 3.3 and later now uses the 2010 compiler. To best way to solve the issue is to just install Visual C++ Express 2010 for free.

Now comes the harder part for 64 bit users and to be honest I just moved to 32 bit but 2010 express doesn't come with a 64 bit compiler (you get a new error, ValueError: ['path'] ) so you have to install Microsoft SDK 7.1 and follow the directions here to get the 64 bit compiler working with python: Python PIP has issues with path for MS Visual Studio 2010 Express for 64-bit install on Windows 7

It may just be easier for you to use the 32 bit version for now. In addition to getting the compiler working, you can bypass the need to compile many modules by getting the binary wheel file from this locaiton http://www.lfd.uci.edu/~gohlke/pythonlibs/

Just download the .whl file you need, shift + right click the download folder and select "open command window here" and run

pip install module-name.whl 

I used that method on 64 bit 3.4.3 before I broke down and decided to just get a working compiler for pip compiles modules from source by default, which is why the binary wheel files work and having pip build from source doesn't.

People getting this (vcvarsall.bat) error on Python 2.7 can instead install "Microsoft Visual C++ Compiler for Python 2.7"

jQuery get content between <div> tags

var x = '<p>blah</p><div><a href="http://bs.serving-sys.com/BurstingPipe/adServer.bs?cn=brd&FlightID=2997227&Page=&PluID=0&Pos=9088" target="_blank"><img src="http://bs.serving-sys.com/BurstingPipe/adServer.bs?cn=bsr&FlightID=2997227&Page=&PluID=0&Pos=9088" border=0 width=300 height=250></a></div>';
$(x).children('div').html();

How does a ArrayList's contains() method evaluate objects?

class Thing {  
    public int value;  

    public Thing (int x) {
        value = x;
    }

    equals (Thing x) {
        if (x.value == value) return true;
        return false;
    }
}

You must write:

class Thing {  
    public int value;  

    public Thing (int x) {
        value = x;
    }

    public boolean equals (Object o) {
    Thing x = (Thing) o;
        if (x.value == value) return true;
        return false;
    }
}

Now it works ;)

What is difference between monolithic and micro kernel?

Monolithic kernel has all kernel services along with kernel core part, thus are heavy and has negative impact on speed and performance. On the other hand micro kernel is lightweight causing increase in performance and speed.
I answered same question at wordpress site. For the difference between monolithic, microkernel and exokernel in tabular form, you can visit here

How do I remove blue "selected" outline on buttons?

This is an issue in the Chrome family and has been there forever.

A bug has been raised https://bugs.chromium.org/p/chromium/issues/detail?id=904208

It can be shown here: https://codepen.io/anon/pen/Jedvwj as soon as you add a border to anything button-like (say role="button" has been added to a tag for example) Chrome messes up and sets the focus state when you click with your mouse. You should see that outline only on keyboard tab-press.

I highly recommend using this fix: https://github.com/wicg/focus-visible.

Just do the following

npm install --save focus-visible

Add the script to your html:

<script src="/node_modules/focus-visible/dist/focus-visible.min.js"></script>

or import into your main entry file if using webpack or something similar:

import 'focus-visible/dist/focus-visible.min';

then put this in your css file:

// hide the focus indicator if element receives focus via mouse, but show on keyboard focus (on tab).
.js-focus-visible :focus:not(.focus-visible) {
  outline: none;
}

// Define a strong focus indicator for keyboard focus.
// If you skip this then the browser's default focus indicator will display instead
// ideally use outline property for those users using windows high contrast mode
.js-focus-visible .focus-visible {
  outline: magenta auto 5px;
}

You can just set:

button:focus {outline:0;}

but if you have a large number of users, you're disadvantaging those who cannot use mice or those who just want to use their keyboard for speed.

Difference between webdriver.get() and webdriver.navigate()

Otherwise you prob want the get method:

Load a new web page in the current browser window. This is done using an
HTTP GET operation, and the method will block until the load is complete.

Navigate allows you to work with browser history as far as i understand it.

Java: Finding the highest value in an array

Easiest way which I've found, supports all android versions

Arrays.sort(series1Numbers);

int maxSeries = Integer.parseInt(String.valueOf(series1Numbers[series1Numbers.length-1]));

Use of "this" keyword in C++

It's programmer preference. Personally, I love using this since it explicitly marks the object members. Of course the _ does the same thing (only when you follow the convention)

Printing to the console in Google Apps Script?

Just to build on vinnief's hacky solution above, I use MsgBox like this:

Browser.msgBox('BorderoToMatriz', Browser.Buttons.OK_CANCEL);

and it acts kinda like a break point, stops the script and outputs whatever string you need to a pop-up box. I find especially in Sheets, where I have trouble with Logger.log, this provides an adequate workaround most times.

How to Convert datetime value to yyyymmddhhmmss in SQL server?

SELECT REPLACE(REPLACE(REPLACE(CONVERT(VARCHAR(19), CONVERT(DATETIME, getdate(), 112), 126), '-', ''), 'T', ''), ':', '') 

How to create a testflight invitation code?

after you add the user for testing. the user should get an email. open that email by your iOS device, then click "Start testing" it will bring you to testFlight to download the app directly. If you open that email via computer, and then click "Start testing" it will show you another page which have the instruction of how to install the app. and that invitation code is on the last line. those All upper case letters is the code.

How to get hostname from IP (Linux)?

To find a hostname in your local network by IP address you can use:

nmblookup -A <ip>

To find a hostname on the internet you could use the host program:

host <ip>

Or you can install nbtscan by running:

sudo apt-get install nbtscan

And use:

nbtscan <ip>

*Taken from https://askubuntu.com/questions/205063/command-to-get-the-hostname-of-remote-server-using-ip-address/205067#205067

Update 2018-05-13

You can query a name server with nslookup. It works both ways!

nslookup <IP>
nslookup <hostname>

Check if value exists in dataTable?

You can use LINQ-to-DataSet with Enumerable.Any:

String author = "John Grisham";
bool contains = tbl.AsEnumerable().Any(row => author == row.Field<String>("Author"));

Another approach is to use DataTable.Select:

DataRow[] foundAuthors = tbl.Select("Author = '" + searchAuthor + "'");
if(foundAuthors.Length != 0)
{
    // do something...
}

Q: what if we do not know the columns Headers and we want to find if any cell value PEPSI exist in any rows'c columns? I can loop it all to find out but is there a better way? –

Yes, you can use this query:

DataColumn[] columns = tbl.Columns.Cast<DataColumn>().ToArray();
bool anyFieldContainsPepsi = tbl.AsEnumerable()
    .Any(row => columns.Any(col => row[col].ToString() == "PEPSI"));

Import a custom class in Java

First off, avoid using the default package.

Second of all, you don't need to import the class; it's in the same package.

Comments in Markdown

I use standard HTML tags, like

<!---
your comment goes here
and here
-->

Note the triple dash. The advantage is that it works with pandoc when generating TeX or HTML output. More information is available on the pandoc-discuss group.

Subtracting 1 day from a timestamp date

Use the INTERVAL type to it. E.g:

--yesterday
SELECT NOW() - INTERVAL '1 DAY';

--Unrelated to the question, but PostgreSQL also supports some shortcuts:
SELECT 'yesterday'::TIMESTAMP, 'tomorrow'::TIMESTAMP, 'allballs'::TIME;

Then you can do the following on your query:

SELECT 
    org_id,
    count(accounts) AS COUNT,
    ((date_at) - INTERVAL '1 DAY') AS dateat
FROM 
    sourcetable
WHERE 
    date_at <= now() - INTERVAL '130 DAYS'
GROUP BY 
    org_id,
    dateat;


TIPS

Tip 1

You can append multiple operands. E.g.: how to get last day of current month?

SELECT date_trunc('MONTH', CURRENT_DATE) + INTERVAL '1 MONTH - 1 DAY';

Tip 2

You can also create an interval using make_interval function, useful when you need to create it at runtime (not using literals):

SELECT make_interval(days => 10 + 2);
SELECT make_interval(days => 1, hours => 2);
SELECT make_interval(0, 1, 0, 5, 0, 0, 0.0);


More info:

Date/Time Functions and Operators

datatype-datetime (Especial values).

Remove all files in a directory

Although this is an old question, I think none has already answered using this approach:

# python 2.7
import os

d='/home/me/test'
filesToRemove = [os.path.join(d,f) for f in os.listdir(d)]
for f in filesToRemove:
    os.remove(f) 

Error: EACCES: permission denied

This solved my issue straight away - mac Mojave 10.14.6 - PhpStorm.

Unhandled rejection Error: EACCES: permission denied, mkdir '/Users/myname/.npm/_cacache/index-v5/fb/5a'

sudo chown -R $USER:$GROUP ~/.npm
sudo chown -R $USER:$GROUP ~/.config

Original post: https://stackoverflow.com/a/50639828

invalid types 'int[int]' for array subscript

Just for completeness, this error can happen also in a different situation: when you declare an array in an outer scope, but declare another variable with the same name in an inner scope, shadowing the array. Then, when you try to index the array, you are actually accessing the variable in the inner scope, which might not even be an array, or it might be an array with fewer dimensions.

Example:

int a[10];  // a global scope

void f(int a)   // a declared in local scope, overshadows a in global scope
{
  printf("%d", a[0]);  // you trying to access the array a, but actually addressing local argument a
}

Install pip in docker

While T. Arboreus's answer might fix the issues with resolving 'archive.ubuntu.com', I think the last error you're getting says that it doesn't know about the packages php5-mcrypt and python-pip. Nevertheless, the reduced Dockerfile of you with just these two packages worked for me (using Debian 8.4 and Docker 1.11.0), but I'm not quite sure if that could be the case because my host system is different than yours.

FROM ubuntu:14.04

# Install dependencies
RUN apt-get update && apt-get install -y \
    php5-mcrypt \
    python-pip

However, according to this answer you should think about installing the python3-pip package instead of the python-pip package when using Python 3.x.

Furthermore, to make the php5-mcrypt package installation working, you might want to add the universe repository like it's shown right here. I had trouble with the add-apt-repository command missing in the Ubuntu Docker image so I installed the package software-properties-common at first to make the command available.

Splitting up the statements and putting apt-get update and apt-get install into one RUN command is also recommended here.

Oh and by the way, you actually don't need the -y flag at apt-get update because there is nothing that has to be confirmed automatically.

Finally:

FROM ubuntu:14.04

# Install dependencies
RUN apt-get update && apt-get install -y \
    software-properties-common
RUN add-apt-repository universe
RUN apt-get update && apt-get install -y \
    apache2 \
    curl \
    git \
    libapache2-mod-php5 \
    php5 \
    php5-mcrypt \
    php5-mysql \
    python3.4 \
    python3-pip

Remark: The used versions (e.g. of Ubuntu) might be outdated in the future.

json parsing error syntax error unexpected end of input

Unexpected end of input means that the parser has ended prematurely. For example, it might be expecting "abcd...wxyz" but only sees "abcd...wxy.

This can be a typo error somewhere, or it could be a problem you get when encodings are mixed across different parts of the application.

One example: consider you are receiving data from a native app using chrome.runtime.sendNativeMessage:

chrome.runtime.sendNativeMessage('appname', {toJSON:()=>{return msg}}, (data)=>{
    console.log(data);
});

Now before your callback is called, the browser would attempt to parse the message using JSON.parse which can give you "unexpected end of input" errors if the supplied byte length does not match the data.

Java Desktop application: SWT vs. Swing

I would use Swing for a couple of reasons.

  • It has been around longer and has had more development effort applied to it. Hence it is likely more feature complete and (maybe) has fewer bugs.

  • There is lots of documentation and other guidance on producing performant applications.

  • It seems like changes to Swing propagate to all platforms simultaneously while changes to SWT seem to appear on Windows first, then Linux.

If you want to build a very feature-rich application, you might want to check out the NetBeans RCP (Rich Client Platform). There's a learning curve, but you can put together nice applications quickly with a little practice. I don't have enough experience with the Eclipse platform to make a valid judgment.

If you don't want to use the entire RCP, NetBeans also has many useful components that can be pulled out and used independently.

One other word of advice, look into different layout managers. They tripped me up for a long time when I was learning. Some of the best aren't even in the standard library. The MigLayout (for both Swing and SWT) and JGoodies Forms tools are two of the best in my opinion.

From milliseconds to hour, minutes, seconds and milliseconds

milliseconds = 12884983  // or x milliseconds
hr = 0
min = 0
sec = 0 
day = 0
while (milliseconds >= 1000) {
  milliseconds = (milliseconds - 1000)
  sec = sec + 1
  if (sec >= 60) min = min + 1
  if (sec == 60) sec = 0
  if (min >= 60) hr = hr + 1
  if (min == 60) min = 0
  if (hr >= 24) {
    hr = (hr - 24)
    day = day + 1
  }
}

I hope that my shorter method will help you

How do I reference to another (open or closed) workbook, and pull values back, in VBA? - Excel 2007

You will have to open the file in one way or another if you want to access the data within it. Obviously, one way is to open it in your Excel application instance, e.g.:-

(untested code)

Dim wbk As Workbook
Set wbk = Workbooks.Open("C:\myworkbook.xls")

' now you can manipulate the data in the workbook anyway you want, e.g. '

Dim x As Variant
x = wbk.Worksheets("Sheet1").Range("A6").Value

Call wbk.Worksheets("Sheet2").Range("A1:G100").Copy
Call ThisWorbook.Worksheets("Target").Range("A1").PasteSpecial(xlPasteValues)
Application.CutCopyMode = False

' etc '

Call wbk.Close(False)

Another way to do it would be to use the Excel ADODB provider to open a connection to the file and then use SQL to select data from the sheet you want, but since you are anyway working from within Excel I don't believe there is any reason to do this rather than just open the workbook. Note that there are optional parameters for the Workbooks.Open() method to open the workbook as read-only, etc.

Should I always use a parallel stream when possible?

Never parallelize an infinite stream with a limit. Here is what happens:

    public static void main(String[] args) {
        // let's count to 1 in parallel
        System.out.println(
            IntStream.iterate(0, i -> i + 1)
                .parallel()
                .skip(1)
                .findFirst()
                .getAsInt());
    }

Result

    Exception in thread "main" java.lang.OutOfMemoryError
        at ...
        at java.base/java.util.stream.IntPipeline.findFirst(IntPipeline.java:528)
        at InfiniteTest.main(InfiniteTest.java:24)
    Caused by: java.lang.OutOfMemoryError: Java heap space
        at java.base/java.util.stream.SpinedBuffer$OfInt.newArray(SpinedBuffer.java:750)
        at ...

Same if you use .limit(...)

Explanation here: Java 8, using .parallel in a stream causes OOM error

Similarly, don't use parallel if the stream is ordered and has much more elements than you want to process, e.g.

public static void main(String[] args) {
    // let's count to 1 in parallel
    System.out.println(
            IntStream.range(1, 1000_000_000)
                    .parallel()
                    .skip(100)
                    .findFirst()
                    .getAsInt());
}

This may run much longer because the parallel threads may work on plenty of number ranges instead of the crucial one 0-100, causing this to take very long time.

how to check if item is selected from a comboBox in C#

Use:

if(comboBox.SelectedIndex > -1) //somthing was selected

To get the selected item you do:

Item m = comboBox.Items[comboBox.SelectedIndex];

As Matthew correctly states, to get the selected item you could also do

Item m = comboBox.SelectedItem;

Getting coordinates of marker in Google Maps API

One more alternative options

var map = new google.maps.Map(document.getElementById('map_canvas'), {
    zoom: 1,
    center: new google.maps.LatLng(35.137879, -82.836914),
    mapTypeId: google.maps.MapTypeId.ROADMAP
});

var myMarker = new google.maps.Marker({
    position: new google.maps.LatLng(47.651968, 9.478485),
    draggable: true
});

google.maps.event.addListener(myMarker, 'dragend', function (evt) {
    document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + evt.latLng.lat().toFixed(3) + ' Current Lng: ' + evt.latLng.lng().toFixed(3) + '</p>';
});

google.maps.event.addListener(myMarker, 'dragstart', function (evt) {
    document.getElementById('current').innerHTML = '<p>Currently dragging marker...</p>';
});

map.setCenter(myMarker.position);
myMarker.setMap(map);

and html file

<body>
    <section>
        <div id='map_canvas'></div>
        <div id="current">Nothing yet...</div>
    </section>
</body>

What is the meaning of Bus: error 10 in C

str2 is pointing to a statically allocated constant character array. You can't write to it/over it. You need to dynamically allocate space via the *alloc family of functions.

Get top 1 row of each group

I just learned how to use cross apply. Here's how to use it in this scenario:

 select d.DocumentID, ds.Status, ds.DateCreated 
 from Documents as d 
 cross apply 
     (select top 1 Status, DateCreated
      from DocumentStatusLogs 
      where DocumentID = d.DocumentId
      order by DateCreated desc) as ds

SSRS the definition of the report is invalid

I just had this same problem during a SSRS development of a Custom Report for MS CRM Dynamics 2011.

The reason because it occurred is because I am using some Hidden Parameters and for some of them I forget to give a default value.

So, because of I have few time to finish the report I forget to put the default value for some Parameters and I risked to lost more time to fix it.

Luckily I found it very fast because the error shows the textbox and the paragraph with the first wrong parameter but it didn't shows the name of the parameter:

"I cannot post the image of the error because this website don't allows me"

In general during SSRS developments it's very important to remember: - To put the report parameters in the correct sequence (the referred ones for first es. parameters inherited from master report or parameters essentials for sub-datasets) - To assign a default value to the Hide and Internal Parameters.

What is EOF in the C programming language?

to keep it simple: EOF is an integer type with value -1. Therefore, we must use an integer variable to test EOF.

C# Passing Function as Argument

There are a couple generic types in .Net (v2 and later) that make passing functions around as delegates very easy.

For functions with return types, there is Func<> and for functions without return types there is Action<>.

Both Func and Action can be declared to take from 0 to 4 parameters. For example, Func < double, int > takes one double as a parameter and returns an int. Action < double, double, double > takes three doubles as parameters and returns nothing (void).

So you can declare your Diff function to take a Func:

public double Diff(double x, Func<double, double> f) {
    double h = 0.0000001;

    return (f(x + h) - f(x)) / h;
}

And then you call it as so, simply giving it the name of the function that fits the signature of your Func or Action:

double result = Diff(myValue, Function);

You can even write the function in-line with lambda syntax:

double result = Diff(myValue, d => Math.Sqrt(d * 3.14));

Lock screen orientation (Android)

inside the Android manifest file of your project, find the activity declaration of whose you want to fix the orientation and add the following piece of code ,

android:screenOrientation="landscape"

for landscape orientation and for portrait add the following code,

android:screenOrientation="portrait"

trying to animate a constraint in swift

You need to first change the constraint and then animate the update.
This should be in the superview.

self.nameInputConstraint.constant = 8

Swift 2

UIView.animateWithDuration(0.5) {
    self.view.layoutIfNeeded()
}

Swift 3, 4, 5

UIView.animate(withDuration: 0.5) {
    self.view.layoutIfNeeded()
}

Bootstrap: wider input field

I made a wider input field by using either span4 or span6 as class.

<input type="text" class="span6 input-large search-query">

This way you don't need the additional custom css, mentioned earlier.

ffmpeg usage to encode a video to H264 codec format

I used these options to convert to the H.264/AAC .mp4 format for HTML5 playback (I think it may help other guys with this problem in some way):

ffmpeg -i input.flv -vcodec mpeg4 -acodec aac output.mp4

UPDATE

As @LordNeckbeard mentioned, the previous line will produce MPEG-4 Part 2 (back in 2012 that worked somehow, I don't remember/understand why). Use the libx264 encoder to produce the proper video with H.264/AAC. To test the output file you can just drag it to a browser window and it should playback just fine.

ffmpeg -i input.flv -vcodec libx264 -acodec aac output.mp4

How to use placeholder as default value in select2 framework

In the current version of select2 you just need to add the attribute data-placeholder="A NICE PLACEHOLDER". select2 will automatically assign the placeholder. Please note: adding an empty <option></option> inside the select is still mandatory.

laravel 5.5 The page has expired due to inactivity. Please refresh and try again

Tried different solutions to solve the problem for several weeks without success.

The problem I was facing was caused by upgrading from laravel 5.0 to 5.5 and forgot to update config/session.php

If anyone is facing the problem, try to update the config/session.php to match the version on Laravel you are running

How do I write the 'cd' command in a makefile?

Here is the pattern I've used:

.PHONY: test_py_utils
PY_UTILS_DIR = py_utils
test_py_utils:
    cd $(PY_UTILS_DIR) && black .
    cd $(PY_UTILS_DIR) && isort .
    cd $(PY_UTILS_DIR) && mypy .
    cd $(PY_UTILS_DIR) && pytest -sl .
    cd $(PY_UTILS_DIR) && flake8 .

My motivations for this pattern are:

  • The above solution is simple and readable
  • I read the classic paper "Recursive Make Considered Harmful", which discouraged me from using $(MAKE) -C some_dir all
  • I didn't want to use just one line of code (punctuated by semicolons or &&) because it is less readable, and I fear that I will make a typo when editing the make recipe.
  • I didn't want to use the .ONESHELL special target because:
    • that is a global option that affects all recipes in the makefile
    • using .ONESHELL causes all lines of the recipe to be executed even if one of the earlier lines has failed with a nonzero exit status. Workarounds like calling set -e are possible, but such workarounds would have to be implemented for every recipe in the makefile.

How to change the foreign key referential action? (behavior)

ALTER TABLE DROP FOREIGN KEY fk_name;
ALTER TABLE ADD FOREIGN KEY fk_name(fk_cols)
            REFERENCES tbl_name(pk_names) ON DELETE RESTRICT;

Removing page title and date when printing web page (with CSS?)

You can add this in your stylesheet: @page{size:auto; margin:5mm;} But this discards the page number too

Using boolean values in C

This is what I use:

enum {false, true};
typedef _Bool bool;

_Bool is a built in type in C. It's intended for boolean values.

How to check if activity is in foreground or in visible background?

That's exactly the difference between onPause and onStop events of the activity as described in the Activity class documentation.

If I understand you correctly, what you want to do is call finish() from your activity onStop to terminate it. See the attached image of the Activity Lifecycle Demo App. This is how it looks like when Activity B is launched from Activity A. The order of events is from bottom to top so you can see that Activity A onStop is called after Activity B onResume was already called.

Activity lifecycle demo

In case a dialog is shown your activity is dimmed in the background and only onPause is called.

Streaming a video file to an html5 video player with Node.js so that the video controls continue to work?

Firstly create app.js file in the directory you want to publish.

var http = require('http');
var fs = require('fs');
var mime = require('mime');
http.createServer(function(req,res){
    if (req.url != '/app.js') {
    var url = __dirname + req.url;
        fs.stat(url,function(err,stat){
            if (err) {
            res.writeHead(404,{'Content-Type':'text/html'});
            res.end('Your requested URI('+req.url+') wasn\'t found on our server');
            } else {
            var type = mime.getType(url);
            var fileSize = stat.size;
            var range = req.headers.range;
                if (range) {
                    var parts = range.replace(/bytes=/, "").split("-");
                var start = parseInt(parts[0], 10);
                    var end = parts[1] ? parseInt(parts[1], 10) : fileSize-1;
                    var chunksize = (end-start)+1;
                    var file = fs.createReadStream(url, {start, end});
                    var head = {
                'Content-Range': `bytes ${start}-${end}/${fileSize}`,
                'Accept-Ranges': 'bytes',
                'Content-Length': chunksize,
                'Content-Type': type
                }
                    res.writeHead(206, head);
                    file.pipe(res);
                    } else {    
                    var head = {
                'Content-Length': fileSize,
                'Content-Type': type
                    }
                res.writeHead(200, head);
                fs.createReadStream(url).pipe(res);
                    }
            }
        });
    } else {
    res.writeHead(403,{'Content-Type':'text/html'});
    res.end('Sorry, access to that file is Forbidden');
    }
}).listen(8080);

Simply run node app.js and your server shall be running on port 8080. Besides video it can stream all kinds of files.

How to use find command to find all files with extensions from list?

find /path/to -regex ".*\.\(jpg\|gif\|png\|jpeg\)" > log

jQuery returning "parsererror" for ajax request

The problem

window.JSON.parse raises an error in $.parseJSON function.

<pre>
$.parseJSON: function( data ) {
...
// Attempt to parse using the native JSON parser first
if ( window.JSON && window.JSON.parse ) {
return window.JSON.parse( data );
}
...
</pre>

My solution

Overloading JQuery using requirejs tool.

<pre>
define(['jquery', 'jquery.overload'], function() { 
    //Loading jquery.overload
});
</pre>

jquery.overload.js file content

<pre>
define(['jquery'],function ($) { 

    $.parseJSON: function( data ) {
        // Attempt to parse using the native JSON parser first
        /**  THIS RAISES Parsing ERROR
        if ( window.JSON && window.JSON.parse ) {
            return window.JSON.parse( data );
        }
        **/

        if ( data === null ) {
            return data;
        }

        if ( typeof data === "string" ) {

            // Make sure leading/trailing whitespace is removed (IE can't handle it)
            data = $.trim( data );

            if ( data ) {
                // Make sure the incoming data is actual JSON
                // Logic borrowed from http://json.org/json2.js
                if ( rvalidchars.test( data.replace( rvalidescape, "@" )
                    .replace( rvalidtokens, "]" )
                    .replace( rvalidbraces, "")) ) {

                    return ( new Function( "return " + data ) )();
                }
            }
        }

        $.error( "Invalid JSON: " + data );
    }

    return $;

});
</pre>

How do you create a static class in C++?

If you're looking for a way of applying the "static" keyword to a class, like you can in C# for example

static classes are just the compiler hand-holding you and stopping you from writing any instance methods/variables.

If you just write a normal class without any instance methods/variables, it's the same thing, and this is what you'd do in C++

What does it mean to bind a multicast (UDP) socket?

To bind a UDP socket when receiving multicast means to specify an address and port from which to receive data (NOT a local interface, as is the case for TCP acceptor bind). The address specified in this case has a filtering role, i.e. the socket will only receive datagrams sent to that multicast address & port, no matter what groups are subsequently joined by the socket. This explains why when binding to INADDR_ANY (0.0.0.0) I received datagrams sent to my multicast group, whereas when binding to any of the local interfaces I did not receive anything, even though the datagrams were being sent on the network to which that interface corresponded.

Quoting from UNIX® Network Programming Volume 1, Third Edition: The Sockets Networking API by W.R Stevens. 21.10. Sending and Receiving

[...] We want the receiving socket to bind the multicast group and port, say 239.255.1.2 port 8888. (Recall that we could just bind the wildcard IP address and port 8888, but binding the multicast address prevents the socket from receiving any other datagrams that might arrive destined for port 8888.) We then want the receiving socket to join the multicast group. The sending socket will send datagrams to this same multicast address and port, say 239.255.1.2 port 8888.

Select elements by attribute

To select elements having a certain attribute, see the answers above.

To determine if a given jQuery element has a specific attribute I'm using a small plugin that returns true if the first element in ajQuery collection has this attribute:

/** hasAttr
 ** helper plugin returning boolean if the first element of the collection has a certain attribute
 **/
$.fn.hasAttr = function(attr) {
   return 0 < this.length
       && 'undefined' !== typeof attr
       && undefined !== attr
       && this[0].hasAttribute(attr)
}

Concatenate two slices in Go

Appending to and copying slices

The variadic function append appends zero or more values x to s of type S, which must be a slice type, and returns the resulting slice, also of type S. The values x are passed to a parameter of type ...T where T is the element type of S and the respective parameter passing rules apply. As a special case, append also accepts a first argument assignable to type []byte with a second argument of string type followed by .... This form appends the bytes of the string.

append(s S, x ...T) S  // T is the element type of S

s0 := []int{0, 0}
s1 := append(s0, 2)        // append a single element     s1 == []int{0, 0, 2}
s2 := append(s1, 3, 5, 7)  // append multiple elements    s2 == []int{0, 0, 2, 3, 5, 7}
s3 := append(s2, s0...)    // append a slice              s3 == []int{0, 0, 2, 3, 5, 7, 0, 0}

Passing arguments to ... parameters

If f is variadic with final parameter type ...T, then within the function the argument is equivalent to a parameter of type []T. At each call of f, the argument passed to the final parameter is a new slice of type []T whose successive elements are the actual arguments, which all must be assignable to the type T. The length of the slice is therefore the number of arguments bound to the final parameter and may differ for each call site.

The answer to your question is example s3 := append(s2, s0...) in the Go Programming Language Specification. For example,

s := append([]int{1, 2}, []int{3, 4}...)

How to make correct date format when writing data to Excel

Try this solution, in my softwarew work very well:

if (obj != null)
{
    if (obj is DateTime)
    {
        if (DateTime.MinValue == ((DateTime)obj))
        {

            xlWorkSheet.Cells[x,y] = String.Empty;

        }
        else
        {

            dynamic opp = ((DateTime)obj);
            xlWorkSheet.Cells[x,y] = (DateTime)opp;

        }
    }
}

AssertionError: View function mapping is overwriting an existing endpoint function: main

use flask 0.9 instead use the following commands sudo pip uninstall flask

sudo pip install flask==0.9

What is "stdafx.h" used for in Visual Studio?

I just ran into this myself since I'm trying to create myself a bare bones framework but started out by creating a new Win32 Program option in Visual Studio 2017. "stdafx.h" is unnecessary and should be removed. Then you can remove the stupid "stdafx.h" and "stdafx.cpp" that is in your Solution Explorer as well as the files from your project. In it's place, you'll need to put

#include <Windows.h>

instead.

java.net.SocketException: Connection reset by peer: socket write error When serving a file

It is possible for the TCP socket to be "closing" and your code to not have yet been notified.

Here is a animation for the life cycle. http://tcp.cs.st-andrews.ac.uk/index.shtml?page=connection_lifecycle

Basically, the connection was closed by the client. You already have throws IOException and SocketException extends IOException. This is working just fine. You just need to properly handle IOException because it is a normal part of the api.

EDIT: The RST packet occurs when a packet is received on a socket which does not exist or was closed. There is no difference to your application. Depending on the implementation the reset state may stick and closed will never officially occur.

Do I need Content-Type: application/octet-stream for file download?

No.

The content-type should be whatever it is known to be, if you know it. application/octet-stream is defined as "arbitrary binary data" in RFC 2046, and there's a definite overlap here of it being appropriate for entities whose sole intended purpose is to be saved to disk, and from that point on be outside of anything "webby". Or to look at it from another direction; the only thing one can safely do with application/octet-stream is to save it to file and hope someone else knows what it's for.

You can combine the use of Content-Disposition with other content-types, such as image/png or even text/html to indicate you want saving rather than display. It used to be the case that some browsers would ignore it in the case of text/html but I think this was some long time ago at this point (and I'm going to bed soon so I'm not going to start testing a whole bunch of browsers right now; maybe later).

RFC 2616 also mentions the possibility of extension tokens, and these days most browsers recognise inline to mean you do want the entity displayed if possible (that is, if it's a type the browser knows how to display, otherwise it's got no choice in the matter). This is of course the default behaviour anyway, but it means that you can include the filename part of the header, which browsers will use (perhaps with some adjustment so file-extensions match local system norms for the content-type in question, perhaps not) as the suggestion if the user tries to save.

Hence:

Content-Type: application/octet-stream
Content-Disposition: attachment; filename="picture.png"

Means "I don't know what the hell this is. Please save it as a file, preferably named picture.png".

Content-Type: image/png
Content-Disposition: attachment; filename="picture.png"

Means "This is a PNG image. Please save it as a file, preferably named picture.png".

Content-Type: image/png
Content-Disposition: inline; filename="picture.png"

Means "This is a PNG image. Please display it unless you don't know how to display PNG images. Otherwise, or if the user chooses to save it, we recommend the name picture.png for the file you save it as".

Of those browsers that recognise inline some would always use it, while others would use it if the user had selected "save link as" but not if they'd selected "save" while viewing (or at least IE used to be like that, it may have changed some years ago).

Add a column to existing table and uniquely number them on MS SQL Server

This will depend on the database but for SQL Server, this could be achieved as follows:

alter table Example
add NewColumn int identity(1,1)

/bin/sh: pushd: not found

here is a method to point

sh -> bash

run this command on terminal

sudo dpkg-reconfigure dash

After this you should see

ls -l /bin/sh

point to /bin/bash (and not to /bin/dash)

Reference

Determine if a String is an Integer in Java

As an alternative approach to trying to parse the string and catching NumberFormatException, you could use a regex; e.g.

if (Pattern.compile("-?[0-9]+").matches(str)) {
    // its an integer
}

This is likely to be faster, especially if you precompile and reuse the regex.

However, the problem with this approach is that Integer.parseInt(str) will also fail if str represents a number that is outside range of legal int values. While it is possible to craft a regex that only matches integers in the range Integer.MIN_INT to Integer.MAX_INT, it is not a pretty sight. (And I am not going to try it ...)

On the other hand ... it may be acceptable to treat "not an integer" and "integer too large" separately for validation purposes.

Floating point vs integer calculations on modern hardware

Addition is much faster than rand, so your program is (especially) useless.

You need to identify performance hotspots and incrementally modify your program. It sounds like you have problems with your development environment that will need to be solved first. Is it impossible to run your program on your PC for a small problem set?

Generally, attempting FP jobs with integer arithmetic is a recipe for slow.

HTML5 video - show/hide controls programmatically

<video id="myvideo">
  <source src="path/to/movie.mp4" />
</video>

<p onclick="toggleControls();">Toggle</p>

<script>
var video = document.getElementById("myvideo");

function toggleControls() {
  if (video.hasAttribute("controls")) {
     video.removeAttribute("controls")   
  } else {
     video.setAttribute("controls","controls")   
  }
}
</script>

See it working on jsFiddle: http://jsfiddle.net/dgLds/

Adding files to java classpath at runtime

yes, you can. it will need to be in its package structure in a separate directory from the rest of your compiled code if you want to isolate it. you will then just put its base dir in the front of the classpath on the command line.

find a minimum value in an array of floats

If min value in array, you can try like:

>>> mydict = {"a": -1.5, "b": -1000.44, "c": -3}
>>> min(mydict.values())
-1000.44

How to delete a record in Django models?

If you want to delete one item

wishlist = Wishlist.objects.get(id = 20)
wishlist.delete()

If you want to delete all items in Wishlist for example

Wishlist.objects.all().delete()

Nested jQuery.each() - continue/break

The problem here is that while you can return false from within the .each callback, the .each function itself returns the jQuery object. So you have to return a false at both levels to stop the iteration of the loop. Also since there is not way to know if the inner .each found a match or not, we will have to use a shared variable using a closure that gets updated.

Each inner iteration of words refers to the same notFound variable, so we just need to update it when a match is found, and then return it. The outer closure already has a reference to it, so it can break out when needed.

$(sentences).each(function() {
    var s = this;
    var notFound = true;

    $(words).each(function() {
        return (notFound = (s.indexOf(this) == -1));
    });

    return notFound;
});

You can try your example here.

PHP Include for HTML?

You can use php code in files with extension .php and only there (iff other is not defined in your server settings).

Just rename your file *.html to *.php


If you want to allow php code processing in files of different format, you have two options to do that:

1) Modifying httpd.conf to allow this for all projects on your server, by adding:

AddHandler application/x-httpd-php .htm .html

2) Creating .htaccess file in your separate project top directory with:

<Files />
    AddType application/x-httpd-php .html
</Files>

For second option you need to allow use of .htaccess files in your httpd.conf, by adding the following settings:

AllowOverride All
AccessFileName .htaccess

*that is correct for Apache HTTP Server

Error:(9, 5) error: resource android:attr/dialogCornerRadius not found

Maybe it's too late but i found a solution:

You have to edit in the build.gradle either the compileSdkVersion --> to lastest (now it is 28). Like that:

android {
compileSdkVersion 28
defaultConfig {
    applicationId "NAME_OF_YOUR_PROJECT_DIRECTORY"
    minSdkVersion 21
    targetSdkVersion 28
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}

or you can change the version of implementation:

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    api 'com.android.support:design:27.+'
    implementation 'com.android.support:appcompat-v7:27.1.1'
    implementation 'com.android.support.constraint:constraint-layout:1.1.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

Index was out of range. Must be non-negative and less than the size of the collection parameter name:index

This error is caused when you have enabled paging in Grid view. If you want to delete a record from grid then you have to do something like this.

int index = Convert.ToInt32(e.CommandArgument);
int i = index % 20;
// Here 20 is my GridView's Page Size.
GridViewRow row = gvMainGrid.Rows[i];
int id = Convert.ToInt32(gvMainGrid.DataKeys[i].Value);
new GetData().DeleteRecord(id);
GridView1.DataSource = RefreshGrid();
GridView1.DataBind();

Hope this answers the question.

How do I include inline JavaScript in Haml?

You can actually do what Chris Chalmers does in his answer, but you must make sure that HAML doesn't parse the JavaScript. This approach is actually useful when you need to use a different type than text/javascript, which is was I needed to do for MathJax.

You can use the plain filter to keep HAML from parsing the script and throwing an illegal nesting error:

%script{type: "text/x-mathjax-config"}
  :plain
    MathJax.Hub.Config({
      tex2jax: {
        inlineMath: [["$","$"],["\\(","\\)"]]
      }
    });

Disabling user input for UITextfield in swift

In swift 5, I used following code to disable the textfield

override func viewDidLoad() {
   super.viewDidLoad()
   self.textfield.isEnabled = false
   //e.g
   self.design.isEnabled = false
}

How do I block comment in Jupyter notebook?

Try using the / from the numeric keyboard. Ctrl + / in Chrome wasn't working for me, but when I used the /(division symbol) from the numeric it worked.

How to get and set the current web page scroll position?

The currently accepted answer is incorrect - document.documentElement.scrollTop always returns 0 on Chrome. This is because WebKit uses body for keeping track of scrolling, whereas Firefox and IE use html.

To get the current position, you want:

document.documentElement.scrollTop || document.body.scrollTop

You can set the current position to 1000px down the page like so:

document.documentElement.scrollTop = document.body.scrollTop = 1000;

Or, using jQuery (animate it while you're at it!):

$("html, body").animate({ scrollTop: "1000px" });

How to implement a secure REST API with node.js

There are many questions about REST auth patterns here on SO. These are the most relevant for your question:

Basically you need to choose between using API keys (least secure as the key may be discovered by an unauthorized user), an app key and token combo (medium), or a full OAuth implementation (most secure).

Getting a list of values from a list of dicts

I think as simple as below would give you what you are looking for.

In[5]: ll = [{'value': 'apple', 'blah': 2}, {'value': 'banana', 'blah': 3} , {'value': 'cars', 'blah':4}]
In[6]: ld = [d.get('value', None) for d in ll]
In[7]: ld
Out[7]: ['apple', 'banana', 'cars']

You can do this with a combination of map and lambda as well but list comprehension looks more elegant and pythonic.

For a smaller input list comprehension is way to go but if the input is really big then i guess generators are the ideal way.

In[11]: gd = (d.get('value', None) for d in ll)
In[12]: gd
Out[12]: <generator object <genexpr> at 0x7f5774568b10>
In[13]: '-'.join(gd)
Out[13]: 'apple-banana-cars'

Here is a comparison of all possible solutions for bigger input

 In[2]: l = [{'value': 'apple', 'blah': 2}, {'value': 'banana', 'blah': 3} , {'value': 'cars', 'blah':4}] * 9000000
In[3]: def gen_version():
  ...:     for i in l:
  ...:         yield i.get('value', None)
  ...: 
In[4]: def list_comp_verison():
  ...:     return [i.get('value', None) for i in l]
  ...: 
In[5]: def list_verison():
  ...:     ll = []
  ...:     for i in l:
  ...:         ll.append(i.get('value', None))
  ...:     return ll
In[10]: def map_lambda_version():
   ...:      m = map(lambda i:i.get('value', None), l)
   ...:      return m
   ...: 
In[11]: %timeit gen_version()
172 ns ± 0.393 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)
In[12]: %timeit map_lambda_version()
203 ns ± 2.31 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
In[13]: %timeit list_comp_verison()
1.61 s ± 20.4 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
In[14]: %timeit list_verison()
2.29 s ± 4.58 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)

As you can see, generators are a better solution in comparison to the others, map is also slower compared to generator for reason I will leave up to OP to figure out.

How to check whether an array is empty using PHP?

if you are to check the array content you may use:

$arr = array();

if(!empty($arr)){
  echo "not empty";
}
else 
{
  echo "empty";
}

see here: http://codepad.org/EORE4k7v

Android: How can I get the current foreground activity (from a service)?

Just recently found out about this. With apis as:

  • minSdkVersion 19
  • targetSdkVersion 26

    ActivityManager.getCurrentActivity(context)

Hope this is of any use.

error C2065: 'cout' : undeclared identifier

Such a silly solution in my case:

// Example a
#include <iostream>    
#include "stdafx.h"

The above was odered as per example a, when I changed it to resemble example b below...

// Example b
#include "stdafx.h"
#include <iostream>  

My code compiled like a charm. Try it, guaranteed to work.

UINavigationBar Hide back Button Text

to remove the Text from backbutton programmatically, used below Code this will work form xcode7 and above.

self.navigationController.navigationBar.topItem.title = @" ";

or

manualLy in storyboards, select the navigation bar on the view controller and put " " in back button text.

this will work. thanks

How do I copy a range of formula values and paste them to a specific range in another sheet?

You can change

Range("B3:B65536").Copy Destination:=Sheets("DB").Range("B" & lastrow)

to

Range("B3:B65536").Copy 
Sheets("DB").Range("B" & lastrow).PasteSpecial xlPasteValues

BTW, if you have xls file (excel 2003), you would get an error if your lastrow would be greater 3.

Try to use this code instead:

Sub Get_Data()
    Dim lastrowDB As Long, lastrow As Long
    Dim arr1, arr2, i As Integer

    With Sheets("DB")
        lastrowDB = .Cells(.Rows.Count, "A").End(xlUp).Row + 1
    End With

    arr1 = Array("B", "C", "D", "E", "F", "AH", "AI", "AJ", "J", "P", "AF")
    arr2 = Array("B", "A", "C", "P", "D", "E", "G", "F", "H", "I", "J")

    For i = LBound(arr1) To UBound(arr1)
        With Sheets("Sheet1")
             lastrow = Application.Max(3, .Cells(.Rows.Count, arr1(i)).End(xlUp).Row)
             .Range(.Cells(3, arr1(i)), .Cells(lastrow, arr1(i))).Copy
             Sheets("DB").Range(arr2(i) & lastrowDB).PasteSpecial xlPasteValues
        End With
    Next
    Application.CutCopyMode = False
End Sub

Note, above code determines last non empty row on DB sheet in column A (variable lastrowDB). If you need to find lastrow for each destination column in DB sheet, use next modification:

For i = LBound(arr1) To UBound(arr1)
   With Sheets("DB")
       lastrowDB = .Cells(.Rows.Count, arr2(i)).End(xlUp).Row + 1
   End With

   ' NEXT CODE

Next

You could also use next approach instead Copy/PasteSpecial. Replace

.Range(.Cells(3, arr1(i)), .Cells(lastrow, arr1(i))).Copy
Sheets("DB").Range(arr2(i) & lastrowDB).PasteSpecial xlPasteValues

with

Sheets("DB").Range(arr2(i) & lastrowDB).Resize(lastrow - 2).Value = _
      .Range(.Cells(3, arr1(i)), .Cells(lastrow, arr1(i))).Value

Change input value onclick button - pure javascript or jQuery

using html5 data attribute...

try this

Html

Product price: $<span id="product_price">500</span>

<br>Total price: $500
<br>
<input type="button" data-quantity="2" value="2&#x00A;Qty">
<input type="button" data-quantity="4" class="mnozstvi_sleva" value="4&#x00A;Qty">
<br>Total
<input type="text" id="count" value="1">

JS

$(function(){
$('input:button').click(function () {
  $('#count').val($(this).data('quantity') * $('#product_price').text());
});
});

fiddle here

Find if listA contains any elements not in listB

This piece of code compares two lists both containing a field for a CultureCode like 'en-GB'. This will leave non existing translations in the list. (we needed a dropdown list for not-translated languages for articles)

var compared = supportedLanguages.Where(sl => !existingTranslations.Any(fmt => fmt.CultureCode == sl.Culture)).ToList();

How can I trigger a JavaScript event click


Please call trigger function any where and button will click.


<a href="#" id="myBtn" title="" >Button click </a>

function trigger(){
    document.getElementById("myBtn").click();
}

What is the difference between atan and atan2 in C++?

Another thing to mention is that atan2 is more stable when computing tangents using an expression like atan(y / x) and x is 0 or close to 0.

Not equal string

It should be this:

if (myString!="-1")
{
//Do things
}

Your equals and exclamation are the wrong way round.

How to use a Java8 lambda to sort a stream in reverse order?

Instead of all these complications, this simple step should do the trick for reverse sorting using Lambda .sorted(Comparator.reverseOrder())

Arrays.asList(files).stream()
.filter(file -> isNameLikeBaseLine(file, baseLineFile.getName()))
.sorted(Comparator.reverseOrder()).skip(numOfNewestToLeave)
.forEach(item -> item.delete());

How SQL query result insert in temp table?

Try:

exec('drop table #tab') -- you can add condition 'if table exists'
exec('select * into #tab from tab')

Checking if a number is a prime number in Python

There are many efficient ways to test primality (and this isn't one of them), but the loop you wrote can be concisely rewritten in Python:

def is_prime(a):
    return all(a % i for i in xrange(2, a))

That is, a is prime if all numbers between 2 and a (not inclusive) give non-zero remainder when divided into a.

check null,empty or undefined angularjs

just use -

if(!a) // if a is negative,undefined,null,empty value then...
{
    // do whatever
}
else {
    // do whatever
}

this works because of the == difference from === in javascript, which converts some values to "equal" values in other types to check for equality, as opposed for === which simply checks if the values equal. so basically the == operator know to convert the "", null, undefined to a false value. which is exactly what you need.

System.MissingMethodException: Method not found?

I came across the same situation in my ASP.NET website. I deleted the published files, restarted VS, cleaned and rebuild the project again. After the next publish, the error was gone...

How does Google calculate my location on a desktop?

I've finally worked it out. The biggest issue is how they managed to work out what Wireless networks were around me and how do they know where these networks are.

It "seems" to be something similar to this:

  1. skyhookwireless.com [or similar] Company has mapped the location of many wireless access points, i assume by similar means that google streetview went around and picked up all the photos.
  2. Using Google gears and my browser, we can report which wireless networks i see and have around me
  3. Compare these wireless points to their geolocation and triangulate my position.

Reference: Slashdot

What is use of c_str function In c++

Oh must add my own pick here, you will use this when you encode/decode some string obj you transfer between two programs.

Lets say you use base64encode some array in python, and then you want to decode that into c++. Once you have the string you decode from base64decode in c++. In order to get it back to array of float, all you need to do here is

float arr[1024];
memcpy(arr, ur_string.c_str(), sizeof(float) * 1024);

This is pretty common use I suppose.

Setting property 'source' to 'org.eclipse.jst.jee.server:JSFTut' did not find a matching property

This is not an error. This is a warning. The difference is pretty huge. This particular warning basically means that the <Context> element in Tomcat's server.xml contains an unknown attribute source and that Tomcat doesn't know what to do with this attribute and therefore will ignore it.

Eclipse WTP adds a custom attribute source to the project related <Context> element in the server.xml of Tomcat which identifies the source of the context (the actual project in the workspace which is deployed to the particular server). This way Eclipse can correlate the deployed webapplication with an project in the workspace. Since Tomcat version 6.0.16, any unspecified XML tags and attributes in the server.xml will produce a warning during Tomcat's startup, even though there is no DTD nor XSD for server.xml.

Just ignore it. Your web project is fine. It should run fine. This issue is completely unrelated to JSF.

How can I make space between two buttons in same div?

Put them inside btn-toolbar or some other container, not btn-group. btn-group joins them together. More info on Bootstrap documentation.

Edit: The original question was for Bootstrap 2.x, but the same is still valid for Bootstrap 3 and Bootstrap 4.

In Bootstrap 4 you will need to add appropriate margin to your groups using utility classes, such as mx-2.

How can I discard remote changes and mark a file as "resolved"?

Make sure of the conflict origin: if it is the result of a git merge, see Brian Campbell's answer.

But if is the result of a git rebase, in order to discard remote (their) changes and use local changes, you would have to do a:

git checkout --theirs -- .

See "Why is the meaning of “ours” and “theirs” reversed"" to see how ours and theirs are swapped during a rebase (because the upstream branch is checked out).

Angular 2: Passing Data to Routes?

It changes in angular 2.1.0

In something.module.ts

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { BlogComponent } from './blog.component';
import { AddComponent } from './add/add.component';
import { EditComponent } from './edit/edit.component';
import { RouterModule } from '@angular/router';
import { MaterialModule } from '@angular/material';
import { FormsModule } from '@angular/forms';
const routes = [
  {
    path: '',
    component: BlogComponent
  },
  {
    path: 'add',
    component: AddComponent
  },
  {
    path: 'edit/:id',
    component: EditComponent,
    data: {
      type: 'edit'
    }
  }

];
@NgModule({
  imports: [
    CommonModule,
    RouterModule.forChild(routes),
    MaterialModule.forRoot(),
    FormsModule
  ],
  declarations: [BlogComponent, EditComponent, AddComponent]
})
export class BlogModule { }

To get the data or params in edit component

import { Component, OnInit } from '@angular/core';
import { Router, ActivatedRoute, Params, Data } from '@angular/router';
@Component({
  selector: 'app-edit',
  templateUrl: './edit.component.html',
  styleUrls: ['./edit.component.css']
})
export class EditComponent implements OnInit {
  constructor(
    private route: ActivatedRoute,
    private router: Router

  ) { }
  ngOnInit() {

    this.route.snapshot.params['id'];
    this.route.snapshot.data['type'];

  }
}

PostgreSQL wildcard LIKE for any of a list of words

One 'elegant' solution would be to use full text search: http://www.postgresql.org/docs/9.0/interactive/textsearch.html. Then you would use full text search queries.

How do I escape spaces in path for scp copy in Linux?

works

scp localhost:"f/a\ b\ c" .

scp localhost:'f/a\ b\ c' .

does not work

scp localhost:'f/a b c' .

The reason is that the string is interpreted by the shell before the path is passed to the scp command. So when it gets to the remote the remote is looking for a string with unescaped quotes and it fails

To see this in action, start a shell with the -vx options ie bash -vx and it will display the interpolated version of the command as it runs it.

Ship an application with a database

The SQLiteAssetHelper library makes this task really simple.

It's easy to add as a gradle dependency (but a Jar is also available for Ant/Eclipse), and together with the documentation it can be found at:
https://github.com/jgilfelt/android-sqlite-asset-helper

Note: This project is no longer maintained as stated on above Github link.

As explained in documentation:

  1. Add the dependency to your module's gradle build file:

    dependencies {
        compile 'com.readystatesoftware.sqliteasset:sqliteassethelper:+'
    }
    
  2. Copy the database into the assets directory, in a subdirectory called assets/databases. For instance:
    assets/databases/my_database.db

    (Optionally, you may compress the database in a zip file such as assets/databases/my_database.zip. This isn't needed, since the APK is compressed as a whole already.)

  3. Create a class, for example:

    public class MyDatabase extends SQLiteAssetHelper {
    
        private static final String DATABASE_NAME = "my_database.db";
        private static final int DATABASE_VERSION = 1;
    
        public MyDatabase(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }
    }
    

Counting how many times a certain char appears in a string before any other char appears

This is a similar Solution to find how many email addresses included in a string. This way is more efficient`

int count = 0;
foreach (char c in email.Trim())
    if (c == '@') count++;

Dynamically updating plot in matplotlib

I know I'm late to answer this question, but for your issue you could look into the "joystick" package. I designed it for plotting a stream of data from the serial port, but it works for any stream. It also allows for interactive text logging or image plotting (in addition to graph plotting). No need to do your own loops in a separate thread, the package takes care of it, just give the update frequency you wish. Plus the terminal remains available for monitoring commands while plotting. See http://www.github.com/ceyzeriat/joystick/ or https://pypi.python.org/pypi/joystick (use pip install joystick to install)

Just replace np.random.random() by your real data point read from the serial port in the code below:

import joystick as jk
import numpy as np
import time

class test(jk.Joystick):
    # initialize the infinite loop decorator
    _infinite_loop = jk.deco_infinite_loop()

    def _init(self, *args, **kwargs):
        """
        Function called at initialization, see the doc
        """
        self._t0 = time.time()  # initialize time
        self.xdata = np.array([self._t0])  # time x-axis
        self.ydata = np.array([0.0])  # fake data y-axis
        # create a graph frame
        self.mygraph = self.add_frame(jk.Graph(name="test", size=(500, 500), pos=(50, 50), fmt="go-", xnpts=10000, xnptsmax=10000, xylim=(None, None, 0, 1)))

    @_infinite_loop(wait_time=0.2)
    def _generate_data(self):  # function looped every 0.2 second to read or produce data
        """
        Loop starting with the simulation start, getting data and
    pushing it to the graph every 0.2 seconds
        """
        # concatenate data on the time x-axis
        self.xdata = jk.core.add_datapoint(self.xdata, time.time(), xnptsmax=self.mygraph.xnptsmax)
        # concatenate data on the fake data y-axis
        self.ydata = jk.core.add_datapoint(self.ydata, np.random.random(), xnptsmax=self.mygraph.xnptsmax)
        self.mygraph.set_xydata(t, self.ydata)

t = test()
t.start()
t.stop()

Changing background colour of tr element on mouseover

tr:hover td {background-color:#000;}

Can you run GUI applications in a Docker container?

Xauthority becomes an issue with newer systems. I can either discard any protection with xhost + before running my docker containers, or I can pass in a well prepared Xauthority file. Typical Xauthority files are hostname specific. With docker, each container can have a different host name (set with docker run -h), but even setting the hostname of the container identical to the host system did not help in my case. xeyes (I like this example) simply would ignore the magic cookie and pass no credentials to the server. Hence we get an error message 'No protocol specified Cannot open display'

The Xauthority file can be written in a way so that the hostname does not matter. We need to set the Authentication Family to 'FamilyWild'. I am not sure, if xauth has a proper command line for this, so here is an example that combines xauth and sed to do that. We need to change the first 16 bits of the nlist output. The value of FamilyWild is 65535 or 0xffff.

docker build -t xeyes - << __EOF__
FROM debian
RUN apt-get update
RUN apt-get install -qqy x11-apps
ENV DISPLAY :0
CMD xeyes
__EOF__
XSOCK=/tmp/.X11-unix
XAUTH=/tmp/.docker.xauth
xauth nlist :0 | sed -e 's/^..../ffff/' | xauth -f $XAUTH nmerge -
docker run -ti -v $XSOCK:$XSOCK -v $XAUTH:$XAUTH -e XAUTHORITY=$XAUTH xeyes

How to put two divs side by side

This is just a simple(not-responsive) HTML/CSS translation of the wireframe you provided.

enter image description here

HTML

<div class="container">

  <header>
    <div class="logo">Logo</div>
    <div class="menu">Email/Password</div>
  </header>

  <div class="first-box">
    <p>Video Explaning Site</p>
  </div>

  <div class="second-box">
    <p>Sign up Info</p>
  </div>

  <footer>
    <div>Website Info</div>
  </footer>

</div>

CSS

.container {
  width:900px; 
  height: 150px;
}

header {
  width:900px; 
  float:left; 
  background: pink; 
  height: 50px;
}

.logo {
  float: left;
  padding: 15px
}

.menu {
  float: right;
  padding: 15px
}

.first-box {
  width:300px; 
  float:left; 
  background: green; 
  height: 150px;
  margin: 50px
}

.first-box p {
  color: #ffffff;
  padding-left: 80px;
  padding-top: 50px;
}

.second-box {
  width:300px; 
  height: 150px; 
  float:right; 
  background: blue;
  margin: 50px
}

.second-box p {
  color: #ffffff;
  padding-left: 110px;
  padding-top: 50px;
}

footer {
  width:900px; 
  float:left; 
  background: black; 
  height: 50px;
  color: #ffffff;
}

footer div {
  padding: 15px;
}

How to assign from a function which returns more than one value?

Usually I wrap the output into a list, which is very flexible (you can have any combination of numbers, strings, vectors, matrices, arrays, lists, objects int he output)

so like:

func2<-function(input) {
   a<-input+1
   b<-input+2
   output<-list(a,b)
   return(output)
}

output<-func2(5)

for (i in output) {
   print(i)
}

[1] 6
[1] 7

Is it possible to have SSL certificate for IP address, not domain name?

Yep. Cloudflare uses it for its DNS instructions homepage: https://1.1.1.1

How can foreign key constraints be temporarily disabled using T-SQL?

Right click the table design and go to Relationships and choose the foreign key on the left-side pane and in the right-side pane, set Enforce foreign key constraint to 'Yes' (to enable foreign key constraints) or 'No' (to disable it). enter image description here

invalid conversion from 'const char*' to 'char*'

Well, data.str().c_str() yields a char const* but your function Printfunc() wants to have char*s. Based on the name, it doesn't change the arguments but merely prints them and/or uses them to name a file, in which case you should probably fix your declaration to be

void Printfunc(int a, char const* loc, char const* stream)

The alternative might be to turn the char const* into a char* but fixing the declaration is preferable:

Printfunc(num, addr, const_cast<char*>(data.str().c_str()));

How can I make the computer beep in C#?

In .Net 2.0, you can use Console.Beep().

// Default beep
Console.Beep();

You can also specify the frequency and length of the beep in milliseconds.

// Beep at 5000 Hz for 1 second
Console.Beep(5000, 1000);

For more information refer http://msdn.microsoft.com/en-us/library/8hftfeyw%28v=vs.110%29.aspx

Selecting a Linux I/O Scheduler

You can set this at boot by adding the "elevator" parameter to the kernel cmdline (such as in grub.cfg)

Example:

elevator=deadline

This will make "deadline" the default I/O scheduler for all block devices.

If you'd like to query or change the scheduler after the system has booted, or would like to use a different scheduler for a specific block device, I recommend installing and use the tool ioschedset to make this easy.

https://github.com/kata198/ioschedset

If you're on Archlinux it's available in aur:

https://aur.archlinux.org/packages/ioschedset

Some example usage:

# Get i/o scheduler for all block devices
[username@hostname ~]$ io-get-sched
sda:    bfq
sr0:    bfq

# Query available I/O schedulers
[username@hostname ~]$ io-set-sched --list
mq-deadline kyber bfq none

# Set sda to use "kyber"
[username@hostname ~]$ io-set-sched kyber /dev/sda
Must be root to set IO Scheduler. Rerunning under sudo...

[sudo] password for username:
+ Successfully set sda to 'kyber'!

# Get i/o scheduler for all block devices to assert change
[username@hostname ~]$ io-get-sched
sda:    kyber
sr0:    bfq

# Set all block devices to use 'deadline' i/o scheduler
[username@hostname ~]$ io-set-sched deadline
Must be root to set IO Scheduler. Rerunning under sudo...

+ Successfully set sda to 'deadline'!
+ Successfully set sr0 to 'deadline'!

# Get the current block scheduler just for sda
[username@hostname ~]$ io-get-sched sda
sda:    mq-deadline

Usage should be self-explanatory. The tools are standalone and only require bash.

Hope this helps!

EDIT: Disclaimer, these are scripts I wrote.

How does Python's super() work with multiple inheritance?

Your code, and the other answers, are all buggy. They are missing the super() calls in the first two classes that are required for co-operative subclassing to work.

Here is a fixed version of the code:

class First(object):
    def __init__(self):
        super(First, self).__init__()
        print("first")

class Second(object):
    def __init__(self):
        super(Second, self).__init__()
        print("second")

class Third(First, Second):
    def __init__(self):
        super(Third, self).__init__()
        print("third")

The super() call finds the next method in the MRO at each step, which is why First and Second have to have it too, otherwise execution stops at the end of Second.__init__().

This is what I get:

>>> Third()
second
first
third

TypeError: 'list' object is not callable while trying to access a list

I also got the error when I called a function that had the same name as another variable that was classified as a list.

Once I sorted out the naming the error was resolved.

Add/Delete table rows dynamically using JavaScript

I used some of the solutions indicated above plus solutions from other postings to come up with a working solution for a dynamic table containing input fields. I'm doing this because it might help someone who finds this thread after searching for the same things that led me to it, and also because the accepted answer (and associated jsfiddle) doesn't actually work! That is, it doesn't index the table rows correctly after a number of inserts/deletes. The key issue is how to uniquely index the dynamic row data, which is possible with a bit of jquery:

<form id=frmLines>
  <table id=tabLines>
  <tr>
    <td>img src='/some/suitable/graphic' onclick='removeLine(this);'/></td>
    <td><input type='text' name='field1' /></td>
    <td><input type='text' name='field2' /></td>
    <td><input type='text' name='field3' /></td>
  </tr>
  <tr>
    <td><img src='/some/suitable/graphic' onclick='addLine();' /></td>
    <td colspan=3>&nbsp;</td>
  </tr>
  </table>
</form>

Note the form and table have id's for direct DOM referencing, but you can't use id's on the input fields as to make them unique you'd need to introduce an index which would massively complicate the code - and its easy enough to access them by name when the form is processed (see below)

Then the javascript to control adding and removing lines is like this:

function addLine() {
  var tabLines = document.getElementById("tabLines");
  var tabLinesRow = tabLines.insertRow(tabLines.rows.length-1);
  var col1html = "<img src='/some/suitable/graphic' onclick='removeLine(this);'>";
  var col2html = "<input type='text' name='field1' />";
  var col3html = "<input type='text' name='field2' />";
  var col4html = "<input type='text' name='field3' />";

  var col1 = tabLinesRow.insertCell(0); col1.innerHTML=col1html;
  var col2 = tabLinesRow.insertCell(1); col2.innerHTML=col2html;
  var col3 = tabLinesRow.insertCell(2); col3.innerHTML=col3html;
  var col4 = tabLinesRow.insertCell(3); col4.innerHTML=col4html;
}

function removeLine(lineItem) {
  var row = lineItem.parentNode.parentNode;
  row.parentNode.removeChild(row);
}

Then the final part of the jigsaw - the javascript to process the form data when its submitted. The key jquery function here is .eq() - which allows you to access the field names in the order they appear in the form - i.e. in table row order.

var frmData = {};              // an object to contain all form data
var arrLines = new Array();    // array to contain the dynamic lines

var tabLines = document.getElementById("tabLines").rows.length-1;

for (i=0;i<tabLines;i++) {
  arrLines[i] = {};
  arrLines[i]['no']     = i+1;
  arrLines[i]['field1'] = $("#frmLines input[name=field1]").eq(i).val();
  arrLines[i]['field2'] = $("#frmLines input[name=field2]").eq(i).val();
  arrLines[i]['field3'] = $("#frmLines input[name=field3]").eq(i).val();
}
frmData['lines'] = arrLines;

frmData['another_field'] = $('#frmLines input[name=another_field]").val();

var jsonData = JSON.stringify(frmData);

// lines of data now in a JSON structure as indexed array
// (plus other fields in the JSON as required)
// ready to post via ajax etc

I hope this helps someone, either directly or indirectly. There are a couple of subtle techniques being used which aren't that complicated but took me 3-4 hours to piece together.