Programs & Examples On #Acquisition

Enable Hibernate logging

Hibernate logging has to be also enabled in hibernate configuration.

Add lines

hibernate.show_sql=true
hibernate.format_sql=true

either to

server\default\deployers\ejb3.deployer\META-INF\jpa-deployers-jboss-beans.xml

or to application's persistence.xml in <persistence-unit><properties> tag.

Anyway hibernate logging won't include (in useful form) info on actual prepared statements' parameters.

There is an alternative way of using log4jdbc for any kind of sql logging.

The above answer assumes that you run the code that uses hibernate on JBoss, not in IDE. In this case you should configure logging also on JBoss in server\default\deploy\jboss-logging.xml, not in local IDE classpath.

Note that JBoss 6 doesn't use log4j by default. So adding log4j.properties to ear won't help. Just try to add to jboss-logging.xml:

   <logger category="org.hibernate">
     <level name="DEBUG"/>
   </logger>

Then change threshold for root logger. See SLF4J logger.debug() does not get logged in JBoss 6.

If you manage to debug hibernate queries right from IDE (without deployment), then you should have log4j.properties, log4j, slf4j-api and slf4j-log4j12 jars on classpath. See http://www.mkyong.com/hibernate/how-to-configure-log4j-in-hibernate-project/.

inject bean reference into a Quartz job in Spring?

All those solutions above doesn't work for me with Spring 5 and Hibernate 5 and Quartz 2.2.3 when I want to call transactional methods!

I therefore implemented this solution which automatically starts the scheduler and triggers the jobs. I found a lot of that code at dzone. Because I don't need to create triggers and jobs dynamically I wanted the static triggers to be pre defined via Spring Configuration and only the jobs to be exposed as Spring Components.

My basic configuration look like this

@Configuration
public class QuartzConfiguration {

  @Autowired
  ApplicationContext applicationContext;

  @Bean
  public SchedulerFactoryBean scheduler(@Autowired JobFactory jobFactory) throws IOException {
    SchedulerFactoryBean sfb = new SchedulerFactoryBean();

    sfb.setOverwriteExistingJobs(true);
    sfb.setAutoStartup(true);
    sfb.setJobFactory(jobFactory);

    Trigger[] triggers = new Trigger[] {
        cronTriggerTest().getObject()
    };
    sfb.setTriggers(triggers);
    return sfb;
  }

  @Bean
  public JobFactory cronJobFactory() {
    AutowiringSpringBeanJobFactory jobFactory = new AutowiringSpringBeanJobFactory();
    jobFactory.setApplicationContext(applicationContext);
    return jobFactory;
  }

  @Bean 
  public CronTriggerFactoryBean cronTriggerTest() {
    CronTriggerFactoryBean tfb = new CronTriggerFactoryBean();
    tfb.setCronExpression("0 * * ? * * *");

    JobDetail jobDetail = JobBuilder.newJob(CronTest.class)
                            .withIdentity("Testjob")
                            .build()
                            ;

    tfb.setJobDetail(jobDetail);
    return tfb;
  }

}

As you can see, you have the scheduler and a simple test trigger which is defined via a cron expression. You can obviously choose whatever scheduling expression you like. You then need the AutowiringSpringBeanJobFactory which goes like this

public final class AutowiringSpringBeanJobFactory extends SpringBeanJobFactory implements ApplicationContextAware {

  @Autowired
  private ApplicationContext applicationContext;

  private SchedulerContext schedulerContext;

  @Override
  public void setApplicationContext(final ApplicationContext context) {
    this.applicationContext = context;
  }


  @Override
  protected Object createJobInstance(final TriggerFiredBundle bundle) throws Exception {
    Job job = applicationContext.getBean(bundle.getJobDetail().getJobClass());
    BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(job);

    MutablePropertyValues pvs = new MutablePropertyValues();
    pvs.addPropertyValues(bundle.getJobDetail().getJobDataMap());
    pvs.addPropertyValues(bundle.getTrigger().getJobDataMap());

    if (this.schedulerContext != null)
    {
        pvs.addPropertyValues(this.schedulerContext);
    }
    bw.setPropertyValues(pvs, true);

    return job;
  }  

  public void setSchedulerContext(SchedulerContext schedulerContext) {
    this.schedulerContext = schedulerContext;
    super.setSchedulerContext(schedulerContext);
  }

}

In here you wire your normal application context and your job together. This is the important gap because normally Quartz starts it's worker threads which have no connection to your application context. That is the reason why you can't execute Transactional mehtods. The last thing missing is a job. It can look like that

@Component
public class CronTest implements Job {

  @Autowired
  private MyService s;

  public CronTest() {
  }

  @Override
  public void execute(JobExecutionContext context) throws JobExecutionException {
    s.execute();
  }

}

It's not a perfect solution because you an extra class only for calling your service method. But nevertheless it works.

Configure hibernate to connect to database via JNDI Datasource

I was getting the same error in my IBM Websphere with c3p0 jar files. I have Oracle 10g database. I simply added the oraclejdbc.jar files in the Application server JVM in IBM Classpath using Websphere Console and the error was resolved.

The oraclejdbc.jar should be set with your C3P0 jar files in your Server Class path whatever it be tomcat, glassfish of IBM.

Difference between Statement and PreparedStatement

nothing much to add,

1 - if you want to execute a query in a loop (more than 1 time), prepared statement can be faster, because of optimization that you mentioned.

2 - parameterized query is a good way to avoid SQL Injection. Parameterized querys are only available in PreparedStatement.

Turning off hibernate logging console output

I managed to stop by adding those 2 lines

log4j.logger.org.hibernate.orm.deprecation=error

log4j.logger.org.hibernate=error

Bellow is what my log4j.properties looks like, i just leave some commented lines explaining the log level

# Root logger option
#Level/rules TRACE < DEBUG < INFO < WARN < ERROR < FATAL.
#FATAL: shows messages at a FATAL level only
#ERROR: Shows messages classified as ERROR and FATAL
#WARNING: Shows messages classified as WARNING, ERROR, and FATAL
#INFO: Shows messages classified as INFO, WARNING, ERROR, and FATAL
#DEBUG: Shows messages classified as DEBUG, INFO, WARNING, ERROR, and FATAL
#TRACE : Shows messages classified as TRACE,DEBUG, INFO, WARNING, ERROR, and FATAL
#ALL : Shows messages classified as TRACE,DEBUG, INFO, WARNING, ERROR, and FATAL
#OFF : No log messages display


log4j.rootLogger=INFO, file, console

log4j.logger.main=DEBUG
log4j.logger.org.hibernate.orm.deprecation=error
log4j.logger.org.hibernate=error

#######################################
# Direct log messages to a log file
log4j.appender.file.Threshold=ALL
log4j.appender.file.file=logs/MyProgram.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} %-5p %c{1} - %m%n

# set file size limit
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.MaxFileSize=5MB
log4j.appender.file.MaxBackupIndex=50


#############################################
# Direct log messages to System Out
log4j.appender.console.Threshold=INFO
log4j.appender.console.Target=System.out
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d{HH:mm:ss} %-5p %c{1} - %m%n

Does C++ support 'finally' blocks? (And what's this 'RAII' I keep hearing about?)

why is it that even managed languages provide a finally-block despite resources being deallocated automatically by the garbage collector anyway?

Actually, languages based on Garbage collectors need "finally" more. A garbage collector does not destroy your objects in a timely manner, so it can not be relied upon to clean up non-memory related issues correctly.

In terms of dynamically-allocated data, many would argue that you should be using smart-pointers.

However...

RAII moves the responsibility of exception safety from the user of the object to the designer

Sadly this is its own downfall. Old C programming habits die hard. When you're using a library written in C or a very C style, RAII won't have been used. Short of re-writing the entire API front-end, that's just what you have to work with. Then the lack of "finally" really bites.

Java: notify() vs. notifyAll() all over again

To summarize the excellent detailed explanations above, and in the simplest way I can think of, this is due to the limitations of the JVM built-in monitor, which 1) is acquired on the entire synchronization unit (block or object) and 2) does not discriminate about the specific condition being waited/notified on/about.

This means that if multiple threads are waiting on different conditions and notify() is used, the selected thread may not be the one which would make progress on the newly fulfilled condition - causing that thread (and other currently still waiting threads which would be able to fulfill the condition, etc..) not to be able to make progress, and eventually starvation or program hangup.

In contrast, notifyAll() enables all waiting threads to eventually re-acquire the lock and check for their respective condition, thereby eventually allowing progress to be made.

So notify() can be used safely only if any waiting thread is guaranteed to allow progress to be made should it be selected, which in general is satisfied when all threads within the same monitor check for only one and the same condition - a fairly rare case in real world applications.

Why doesn't Java offer operator overloading?

Assuming Java as the implementation language then a, b, and c would all be references to type Complex with initial values of null. Also assuming that Complex is immutable as the mentioned BigInteger and similar immutable BigDecimal, I'd I think you mean the following, as you're assigning the reference to the Complex returned from adding b and c, and not comparing this reference to a.

Isn't :

Complex a, b, c; a = b + c;

much simpler than:

Complex a, b, c; a = b.add(c);

How to vertically center a "div" element for all browsers using CSS?

For new comers please try

display: flex;
align-items: center;
justify-content: center;

Can't get Python to import from a different folder

The right way to import a module located on a parent folder, when you don't have a standard package structure, is:

import os, sys
CURRENT_DIR = os.path.dirname(os.path.abspath(__file__))
sys.path.append(os.path.dirname(CURRENT_DIR))

(you can merge the last two lines but this way is easier to understand).

This solution is cross-platform and is general enough to need not modify in other circumstances.

ErrorActionPreference and ErrorAction SilentlyContinue for Get-PSSessionConfiguration

A solution for me:

$old_ErrorActionPreference = $ErrorActionPreference
$ErrorActionPreference = 'SilentlyContinue'
if((Get-PSSessionConfiguration -Name "MyShellUri" -ErrorAction SilentlyContinue) -eq $null) {
   WriteTraceForTrans "The session configuration MyShellUri is already unregistered."
}
else {        
   #Unregister-PSSessionConfiguration -Name "MyShellUri" -Force -ErrorAction Ignore
}
$ErrorActionPreference = $old_ErrorActionPreference 

Or use try-catch

try { 

(Get-PSSessionConfiguration -Name "MyShellUri" -ErrorAction SilentlyContinue)

} 
catch {

}

How to clear the cache in NetBeans

The path of the cache directory is listed in the About window (menu Help/About). Close NetBeans, then delete (or rename) the directory. NetBeans will rebuild its cache when it starts up.

UITableViewCell Selected Background Color on Multiple Selection

You can use standard UITableViewDelegate methods

- (nullable NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    EntityTableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    [cell selectMe];
    return indexPath;
}

- (nullable NSIndexPath *)tableView:(UITableView *)tableView willDeselectRowAtIndexPath:(NSIndexPath *)indexPath {
    EntityTableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    [cell deSelectMe];
    return indexPath;
}

in my situation this works, cause we need to select cell, change color, and when user taps 2 times on the selected cell further navigation should be performed.

using nth-child in tables tr td

Current css version still doesn't support selector find by content. But there is a way, by using css selector find by attribute, but you have to put some identifier on all of the <td> that have $ inside. Example: using nth-child in tables tr td

html

<tr>
    <td>&nbsp;</td>
    <td data-rel='$'>$</td>
    <td>&nbsp;</td>
</tr>

css

table tr td[data-rel='$'] {
    background-color: #333;
    color: white;
}

Please try these example.

_x000D_
_x000D_
table tr td[data-content='$'] {_x000D_
    background-color: #333;_x000D_
    color: white;_x000D_
}
_x000D_
<table border="1">_x000D_
    <tr>_x000D_
        <td>A</td>_x000D_
        <td data-content='$'>$</td>_x000D_
        <td>B</td>_x000D_
        <td data-content='$'>$</td>_x000D_
        <td>C</td>_x000D_
        <td data-content='$'>$</td>_x000D_
        <td>D</td>_x000D_
    </tr>_x000D_
</table>
_x000D_
_x000D_
_x000D_

How to close form

for example, if you want to close a windows form when an action is performed there are two methods to do it

1.To close it directly

Form1 f=new Form1();
f.close(); //u can use below comment also
//this.close();

2.We can also hide form without closing it

 private void button1_Click(object sender, EventArgs e)
    {
        Form1 f1 = new Form1();
        Form2 f2 = new Form2();
        int flag = 0;
        string u, p;
        u = textBox1.Text;
        p = textBox2.Text;
        if(u=="username" && p=="pasword")
        {
            flag = 1;
        }
        else
        {
          MessageBox.Show("enter correct details");
        }
        if(flag==1)
        {
            f2.Show();
            this.Hide();
        }

    }

Git diff says subproject is dirty

Update Jan. 2021, ten years later:

"git diff"(man) showed a submodule working tree with untracked cruft as Submodule commit <objectname>-dirty, but a natural expectation is that the "-dirty" indicator would align with "git describe --dirty"(man), which does not consider having untracked files in the working tree as source of dirtiness.
The inconsistency has been fixed with Git 2.31 (Q1 2021).

See commit 8ef9312 (10 Nov 2020) by Sangeeta Jain (sangu09).
(Merged by Junio C Hamano -- gitster -- in commit 0806279, 25 Jan 2021)

diff: do not show submodule with untracked files as "-dirty"

Signed-off-by: Sangeeta Jain

Git diff reports a submodule directory as -dirty even when there are only untracked files in the submodule directory.
This is inconsistent with what git describe --dirty(man) says when run in the submodule directory in that state.

Make --ignore-submodules=untracked the default for git diff(man) when there is no configuration variable or command line option, so that the command would not give '-dirty' suffix to a submodule whose working tree has untracked files, to make it consistent with git describe --dirty that is run in the submodule working tree.

And also make --ignore-submodules=none the default for git status(man) so that the user doesn't end up deleting a submodule that has uncommitted (untracked) files.

git config now includes in its man page:

By default this is set to untracked so that any untracked submodules are ignored.


Original answer (2011)

As mentioned in Mark Longair's blog post Git Submodules Explained,

Versions 1.7.0 and later of git contain an annoying change in the behavior of git submodule.
Submodules are now regarded as dirty if they have any modified files or untracked files, whereas previously it would only be the case if HEAD in the submodule pointed to the wrong commit.

The meaning of the plus sign (+) in the output of git submodule has changed, and the first time that you come across this it takes a little while to figure out what’s going wrong, for example by looking through changelogs or using git bisect on git.git to find the change. It would have been much kinder to users to introduce a different symbol for “at the specified version, but dirty”.

You can fix it by:

  • either committing or undoing the changes/evolutions within each of your submodules, before going back to the parent repo (where the diff shouldn't report "dirty" files anymore). To undo all changes to your submodule just cd into the root directory of your submodule and do git checkout .

dotnetCarpenter comments that you can do a: git submodule foreach --recursive git checkout .

  • or add --ignore-submodules to your git diff, to temporarily ignore those "dirty" submodules.

New in Git version 1.7.2

As Noam comments below, this question mentions that, since git version 1.7.2, you can ignore the dirty submodules with:

git status --ignore-submodules=dirty

Counting number of words in a file

The below code supports in Java 8

//Read file into String

String fileContent=new String(Files.readAlBytes(Paths.get("MyFile.txt")),StandardCharacters.UFT_8);

//Keeping these into list of strings by splitting with a delimiter

List<String> words = Arrays.asList(contents.split("\\PL+"));

int count=0;
for(String x: words){
 if(x.length()>1) count++;
}

sop(x);

C++: Converting Hexadecimal to Decimal

Well, the C way might be something like ...

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

int main()
{
        int n;
        scanf("%d", &n);
        printf("%X", n);

        exit(0);
}

Define global constants

One approach for Angular4 would be defining a constant at module level:

const api_endpoint = 'http://127.0.0.1:6666/api/';

@NgModule({
  declarations: [AppComponent],
  bootstrap: [AppComponent],
  providers: [
    MessageService,
    {provide: 'API_ENDPOINT', useValue: api_endpoint}
  ]
})
export class AppModule {
}

Then, in your service:

import {Injectable, Inject} from '@angular/core';

@Injectable()
export class MessageService {

    constructor(private http: Http, 
      @Inject('API_ENDPOINT') private api_endpoint: string) { }

    getMessages(): Observable<Message[]> {
        return this.http.get(this.api_endpoint+'/messages')
            .map(response => response.json())
            .map((messages: Object[]) => {
                return messages.map(message => this.parseData(message));
            });
    }

    private parseData(data): Message {
        return new Message(data);
    }
}

Does calling clone() on an array also clone its contents?

If I invoke clone() method on array of Objects of type A, how will it clone its elements?

The elements of the array will not be cloned.

Will the copy be referencing to the same objects?

Yes.

Or will it call (element of type A).clone() for each of them?

No, it will not call clone() on any of the elements.

Could not find main class HelloWorld

I had the same problem. Perhaps, the problem is that you have compiled and executed the class with different Java versions.

Make sure the version of the compiler is the same as the command "java":

javac -version

java -version

In Linux, use

sudo update-alternatives --config java

to change the version of Java.

Get the date (a day before current time) in Bash

#!/bin/bash
OFFSET=1;
eval `date "+day=%d; month=%m; year=%Y"`
# Subtract offset from day, if it goes below one use 'cal'
# to determine the number of days in the previous month.
day=`expr $day - $OFFSET`
if [ $day -le 0 ] ;then
month=`expr $month - 1`
if [ $month -eq 0 ] ;then
year=`expr $year - 1`
month=12
fi
set `cal $month $year`
xday=${$#}
day=`expr $xday + $day`
fi
echo $year-$month-$day

Php header location redirect not working

I had similar problem... solved by adding ob_start(); and ob_end_flush(); ...

<?php 
ob_start();


require 'engine/vishnuHTML.class.php';
require 'engine/admin/login.class.php';

$html=new vishnuHTML();
 (!isset($_SESSION))?session_start():"";

/* blah bla Code
...........
...........
 */

</div>
</div>
<?php
}



ob_end_flush();
?>

Think of ob_start() as saying "Start remembering everything that would normally be outputted, but don't quite do anything with it yet."

ob_end_clean() or ob_flush(), which either stops saving things and discards whatever was saved, or stops saving and outputs it all at once, respectively.

Maven error: Not authorized, ReasonPhrase:Unauthorized

The issue may happen while fetching dependencies from a remote repository. In my case, the repository did not need any authentication and it has been resolved by removing the servers section in the settings.xml file:

<servers>
    <server>
      <id>SomeRepo</id>
      <username>SomeUN</username>
      <password>SomePW</password>
    </server>
</servers>

ps: I guess your target is mvn clean install instead of maven install clean

How to Flatten a Multidimensional Array?

As of PHP 5.3 the shortest solution seems to be array_walk_recursive() with the new closures syntax:

function flatten(array $array) {
    $return = array();
    array_walk_recursive($array, function($a) use (&$return) { $return[] = $a; });
    return $return;
}

Capturing TAB key in text box

In Chrome on the Mac, alt-tab inserts a tab character into a <textarea> field.

Here’s one: . Wee!

Disable scrolling in an iPhone web application?

The page has to be launched from the Home screen for the meta tag to work.

Generate a random number in the range 1 - 10

Actually I don't know you want to this.

try this

INSERT INTO my_table (my_column)
SELECT
    (random() * 10) + 1
;

How do I SET the GOPATH environment variable on Ubuntu? What file must I edit?

This is what got it working for me on Ubuntu 15.10 using the fish shell:

# ~/.config/fish/config.fish

set -g -x PATH /usr/local/bin $PATH
set -g -x GOPATH /usr/share/go

Then I had to change the permissions on the go folder (it was set to root)

sudo chown <name>:<name> -R /usr/share/go

Batch File: ( was unexpected at this time

you need double quotes in all your three if statements, eg.:

IF "%a%"=="2" (

@echo OFF &SETLOCAL ENABLEDELAYEDEXPANSION
cls
title ~USB Wizard~
echo What do you want to do?
echo 1.Enable/Disable USB Storage Devices.
echo 2.Enable/Disable Writing Data onto USB Storage.
echo 3.~Yet to come~.


set "a=%globalparam1%"
goto :aCheck
:aPrompt
set /p "a=Enter Choice: "
:aCheck
if "%a%"=="" goto :aPrompt
echo %a%

IF "%a%"=="2" (
    title USB WRITE LOCK
    echo What do you want to do?
    echo 1.Apply USB Write Protection
    echo 2.Remove USB Write Protection
    ::param1
    set "param1=%globalparam2%"
    goto :param1Check
    :param1Prompt
    set /p "param1=Enter Choice: "
    :param1Check
    if "!param1!"=="" goto :param1Prompt

    if "!param1!"=="1" (
         REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies\ /v WriteProtect /t REG_DWORD /d 00000001
         USB Write is Locked!
    )
    if "!param1!"=="2" (
         REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies\ /v WriteProtect /t REG_DWORD /d 00000000
         USB Write is Unlocked!
    )
)
pause

How to update the constant height constraint of a UIView programmatically?

Create an IBOutlet of NSLayoutConstraint of yourView and update the constant value accordingly the condition specifies.

//Connect them from Interface 
@IBOutlet viewHeight: NSLayoutConstraint! 
@IBOutlet view: UIView!

private func updateViewHeight(height:Int){
   guard let aView = view, aViewHeight = viewHeight else{
      return
   }
   aViewHeight.constant = height
   aView.layoutIfNeeded()
}

how can I copy a conditional formatting in Excel 2010 to other cells, which is based on a other cells content?

I had this problem too and couldn't solve it without using VBA.

In my case I had a table with numbers that I wanted to be formatted and a corresponding table next to it with the desired formatting values.

i.e. While column F contains the values I want to format, the desired formatting for each cell is captured in column Z, expressed as "RED", "AMBER" or "GREEN."

Quick solution below. Manually select the range to which to apply the conditional formatting and then run the macro.

   Sub ConditionalFormatting()
For Each Cell In Selection.Cells
With Cell
    'clean
    .FormatConditions.Delete

    'green rule
    .FormatConditions.Add Type:=xlExpression, Formula1:= _
        "=$Z" & Cell.Row & "=""GREEN"""
    .FormatConditions(.FormatConditions.Count).SetFirstPriority
    With .FormatConditions(1).Font
        .Color = -11489280
        .TintAndShade = 0
    End With
    .FormatConditions(1).StopIfTrue = False

    'amber rule
    .FormatConditions.Add Type:=xlExpression, Formula1:= _
        "=$Z" & Cell.Row & "=""AMBER"""
    .FormatConditions(.FormatConditions.Count).SetFirstPriority
    With .FormatConditions(1).Font
        .ThemeColor = xlThemeColorAccent6
        .TintAndShade = -0.249946592608417
    End With
    .FormatConditions(1).StopIfTrue = False

    'red rule
    .FormatConditions.Add Type:=xlExpression, Formula1:= _
        "=$Z" & Cell.Row & "=""RED"""
    .FormatConditions(.FormatConditions.Count).SetFirstPriority
    With .FormatConditions(1).Font
        .Color = -16776961
        .TintAndShade = 0
    End With
    .FormatConditions(1).StopIfTrue = False
End With

Next Cell

End Sub

Multiline TextBox multiple newline

textBox1.Text = "Line1" + Environment.NewLine + "Line2";

Also the markup needs to include TextMode="MultiLine" (otherwise it shows text as one line)

<asp:TextBox ID="multitxt" runat="server" TextMode="MultiLine" ></asp:TextBox>

Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

I found a need for this while programming an iOS-Phone monotouch app controller in a visual studio winforms prototype project outside of xamarin stuidio. Preferring to program in VS over xamarin studio as much as possible, I wanted the controller to be completely decoupled from the phone framework. This way implementing this for other frameworks like Android and Windows Phone would be much easier for future uses.

I wanted a solution where the GUI could respond to events without the burden of dealing with the cross threading switching code behind every button click. Basically let the class controller handle that to keep the client code simple. You could possibly have many events on the GUI where as if you could handle it in one place in the class would be cleaner. I am not a multi theading expert, let me know if this is flawed.

public partial class Form1 : Form
{
    private ExampleController.MyController controller;

    public Form1()
    {          
        InitializeComponent();
        controller = new ExampleController.MyController((ISynchronizeInvoke) this);
        controller.Finished += controller_Finished;
    }

    void controller_Finished(string returnValue)
    {
        label1.Text = returnValue; 
    }

    private void button1_Click(object sender, EventArgs e)
    {
        controller.SubmitTask("Do It");
    }
}

The GUI form is unaware the controller is running asynchronous tasks.

public delegate void FinishedTasksHandler(string returnValue);

public class MyController
{
    private ISynchronizeInvoke _syn; 
    public MyController(ISynchronizeInvoke syn) {  _syn = syn; } 
    public event FinishedTasksHandler Finished; 

    public void SubmitTask(string someValue)
    {
        System.Threading.ThreadPool.QueueUserWorkItem(state => submitTask(someValue));
    }

    private void submitTask(string someValue)
    {
        someValue = someValue + " " + DateTime.Now.ToString();
        System.Threading.Thread.Sleep(5000);
//Finished(someValue); This causes cross threading error if called like this.

        if (Finished != null)
        {
            if (_syn.InvokeRequired)
            {
                _syn.Invoke(Finished, new object[] { someValue });
            }
            else
            {
                Finished(someValue);
            }
        }
    }
}

addClass and removeClass in jQuery - not removing class

I actually just resolved an issue I was having by swapping around the order that I was altering the properties in. For example I was changing the attribute first but I actually had to remove the class and add the new class before modifying the attributes. I'm not sure why it worked but it did. So something to try would be to change from $("XXXX").attr('something').removeClass( "class" ).addClass( "newClass" ) to $("XXXX").removeClass( "class" ).addClass( "newClass" ).attr('something').

Save plot to image file instead of displaying it using Matplotlib

As suggested before, you can either use:

import matplotlib.pyplot as plt
plt.savefig("myfig.png")

For saving whatever IPhython image that you are displaying. Or on a different note (looking from a different angle), if you ever get to work with open cv, or if you have open cv imported, you can go for:

import cv2

cv2.imwrite("myfig.png",image)

But this is just in case if you need to work with Open CV. Otherwise plt.savefig() should be sufficient.

How can I autoformat/indent C code in vim?

I like indent as mentioned above, but most often I want to format only a small section of the file that I'm working on. Since indent can take code from stdin, its really simple:

  1. Select the block of code you want to format with V or the like.
  2. Format by typing :!indent.

astyle takes stdin too, so you can use the same trick there.

Text not wrapping in p tag

You can use word-wrap to break words or a continuous string of characters if it doesn't fit on a line in a container.

word-wrap: break-word;

this will keep breaking lines at appropriate break points unless a single string of characters doesn't fit on a line, in that case it will break.

JSFiddle

Change image size with JavaScript

If you want to resize an image after it is loaded, you can attach to the onload event of the <img> tag. Note that it may not be supported in all browsers (Microsoft's reference claims it is part of the HTML 4.0 spec, but the HTML 4.0 spec doesn't list the onload event for <img>).

The code below is tested and working in: IE 6, 7 & 8, Firefox 2, 3 & 3.5, Opera 9 & 10, Safari 3 & 4 and Google Chrome:

<img src="yourImage.jpg" border="0" height="real_height" width="real_width"
    onload="resizeImg(this, 200, 100);">

<script type="text/javascript">
function resizeImg(img, height, width) {
    img.height = height;
    img.width = width;
}
</script>

Google map V3 Set Center to specific Marker

Once you have markers on the map, you can retrieve the Lat/Long coordinates through the API and use this to set the map's center. You'll first just need to determine which marker you wish to center on - I'll leave that up to you.

// "marker" refers to the Marker object you wish to center on

var latLng = marker.getPosition(); // returns LatLng object
map.setCenter(latLng); // setCenter takes a LatLng object

Info windows are separate objects which are typically bound to a marker, so to open the info window you might do something like this (however it will depend on your code):

var infoWindow = marker.infoWindow; // retrieve the InfoWindow object
infoWindow.open(map); // Trigger the "open()" method

Hope this helps.

How to append rows in a pandas dataframe in a for loop?

I have created a data frame in a for loop with the help of a temporary empty data frame. Because for every iteration of for loop, a new data frame will be created thereby overwriting the contents of previous iteration.

Hence I need to move the contents of the data frame to the empty data frame that was created already. It's as simple as that. We just need to use .append function as shown below :

temp_df = pd.DataFrame() #Temporary empty dataframe
for sent in Sentences:
    New_df = pd.DataFrame({'words': sent.words}) #Creates a new dataframe and contains tokenized words of input sentences
    temp_df = temp_df.append(New_df, ignore_index=True) #Moving the contents of newly created dataframe to the temporary dataframe

Outside the for loop, you can copy the contents of the temporary data frame into the master data frame and then delete the temporary data frame if you don't need it

Change background color on mouseover and remove it after mouseout

If you don't care about IE =6, you could use pure CSS ...

.forum:hover { background-color: #380606; }

_x000D_
_x000D_
.forum { color: white; }_x000D_
.forum:hover { background-color: #380606 !important; }_x000D_
/* we use !important here to override specificity. see http://stackoverflow.com/q/5805040/ */_x000D_
_x000D_
#blue { background-color: blue; }
_x000D_
<meta charset=utf-8>_x000D_
_x000D_
<p class="forum" style="background-color:red;">Red</p>_x000D_
<p class="forum" style="background:green;">Green</p>_x000D_
<p class="forum" id="blue">Blue</p>
_x000D_
_x000D_
_x000D_


With jQuery, usually it is better to create a specific class for this style:

.forum_hover { background-color: #380606; }

and then apply the class on mouseover, and remove it on mouseout.

$('.forum').hover(function(){$(this).toggleClass('forum_hover');});

_x000D_
_x000D_
$(document).ready(function(){_x000D_
  $('.forum').hover(function(){$(this).toggleClass('forum_hover');});_x000D_
});
_x000D_
.forum_hover { background-color: #380606 !important; }_x000D_
_x000D_
.forum { color: white; }_x000D_
#blue { background-color: blue; }
_x000D_
<meta charset=utf-8>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
<p class="forum" style="background-color:red;">Red</p>_x000D_
<p class="forum" style="background:green;">Green</p>_x000D_
<p class="forum" id="blue">Blue</p>
_x000D_
_x000D_
_x000D_


If you must not modify the class, you could save the original background color in .data():

  $('.forum').data('bgcolor', '#380606').hover(function(){
    var $this = $(this);
    var newBgc = $this.data('bgcolor');
    $this.data('bgcolor', $this.css('background-color')).css('background-color', newBgc);
  });

_x000D_
_x000D_
$(document).ready(function(){_x000D_
  $('.forum').data('bgcolor', '#380606').hover(function(){_x000D_
    var $this = $(this);_x000D_
    var newBgc = $this.data('bgcolor');_x000D_
    $this.data('bgcolor', $this.css('background-color')).css('background-color', newBgc);_x000D_
  });_x000D_
});
_x000D_
.forum { color: white; }_x000D_
#blue { background-color: blue; }
_x000D_
<meta charset=utf-8>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
<p class="forum" style="background-color:red;">Red</p>_x000D_
<p class="forum" style="background:green;">Green</p>_x000D_
<p class="forum" id="blue">Blue</p>
_x000D_
_x000D_
_x000D_

or

  $('.forum').hover(
    function(){
      var $this = $(this);
      $this.data('bgcolor', $this.css('background-color')).css('background-color', '#380606');
    },
    function(){
      var $this = $(this);
      $this.css('background-color', $this.data('bgcolor'));
    }
  );   

_x000D_
_x000D_
$(document).ready(function(){_x000D_
  $('.forum').hover(_x000D_
    function(){_x000D_
      var $this = $(this);_x000D_
      $this.data('bgcolor', $this.css('background-color')).css('background-color', '#380606');_x000D_
    },_x000D_
    function(){_x000D_
      var $this = $(this);_x000D_
      $this.css('background-color', $this.data('bgcolor'));_x000D_
    }_x000D_
  );    _x000D_
});
_x000D_
.forum { color: white; }_x000D_
#blue { background-color: blue; }
_x000D_
<meta charset=utf-8>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
<p class="forum" style="background-color:red;">Red</p>_x000D_
<p class="forum" style="background:green;">Green</p>_x000D_
<p class="forum" id="blue">Blue</p>
_x000D_
_x000D_
_x000D_

When to use an interface instead of an abstract class and vice versa?

One interesting location where interfaces fare better than abstract classes is when you need to add extra functionality to a group of (related or unrelated) objects. If you cannot give them a base abstract class (e.g., they are sealed or already have a parent), you can give them a dummy (empty) interface instead, and then simply write extension methods for that interface.

AngularJS - Trigger when radio button is selected

Another approach is using Object.defineProperty to set valueas a getter setter property in the controller scope, then each change on the value property will trigger a function specified in the setter:

The HTML file:

<input type="radio" ng-model="value" value="one"/>
<input type="radio" ng-model="value" value="two"/>
<input type="radio" ng-model="value" value="three"/>

The javascript file:

var _value = null;
Object.defineProperty($scope, 'value', {
  get: function () {
    return _value;
  },         
  set: function (value) {
    _value = value;
    someFunction();
  }
});

see this plunker for the implementation

Android Studio SDK location

C:\Users\Max\AppData\Local\Android\sdk\

The location I found it in for Windows 8.1. I think the default SDK folder. AppData is a hidden folder, so you will not locate it unless you type it in once you get into your C:\Users\ folder.

Tensorflow: how to save/restore a model?

If you use tf.train.MonitoredTrainingSession as the default session, you don't need to add extra code to do save/restore things. Just pass a checkpoint dir name to MonitoredTrainingSession's constructor, it will use session hooks to handle these.

Count unique values in a column in Excel

My data set is D3:D786, Column headings in D2, function in D1. Formula will ignore blank values.

=SUM(IF(FREQUENCY(IF(SUBTOTAL(3,OFFSET(D3,ROW(D3:D786)-ROW(D3),,1)),IF(D3:D786<>"",MATCH("~"&D3:D786,D3:D786&"",0))),ROW(D3:D786)-ROW(D3)+1),1))

When entering the formula, CTRL + SHIFT + ENTER

I found this at the site below, there's more explanations there about Excel that i didn't understand, if you're into that sort of thing.

http://www.mrexcel.com/forum/excel-questions/553903-count-unique-values-filtered-column.html#post2735467

I copied and pasted my dataset into a different sheet to verify it and it's worked for me.

Disabling the long-running-script message in Internet Explorer

This message displays when Internet Explorer reaches the maximum number of synchronous instructions for a piece of JavaScript. The default maximum is 5,000,000 instructions, you can increase this number on a single machine by editing the registry.

Internet Explorer now tracks the total number of executed script statements and resets the value each time that a new script execution is started, such as from a timeout or from an event handler, for the current page with the script engine. Internet Explorer displays a "long-running script" dialog box when that value is over a threshold amount.

The only way to solve the problem for all users that might be viewing your page is to break up the number of iterations your loop performs using timers, or refactor your code so that it doesn't need to process as many instructions.

Breaking up a loop with timers is relatively straightforward:

var i=0;
(function () {
    for (; i < 6000000; i++) {
        /*
            Normal processing here
        */

        // Every 100,000 iterations, take a break
        if ( i > 0 && i % 100000 == 0) {
            // Manually increment `i` because we break
            i++;
            // Set a timer for the next iteration 
            window.setTimeout(arguments.callee);
            break;
        }
    }
})();

Return value from exec(@sql)

that's my procedure

CREATE PROC sp_count
    @CompanyId sysname,
    @codition sysname
    AS
    SET NOCOUNT ON
    CREATE TABLE #ctr
    ( NumRows int )

    DECLARE @intCount int
         , @vcSQL varchar(255)

    SELECT    @vcSQL = ' INSERT #ctr FROM dbo.Comm_Services 
                       WHERE CompanyId = '+@CompanyId+' and '+@condition+')'
    EXEC      (@vcSQL)

    IF @@ERROR = 0
    BEGIN
         SELECT    @intCount = NumRows
         FROM #ctr

         DROP TABLE #ctr
         RETURN @intCount
    END
    ELSE
    BEGIN
         DROP TABLE #ctr
         RETURN -1
    END
    GO

JQUERY: Uncaught Error: Syntax error, unrecognized expression

The "double quote" + 'single quote' combo is not needed

console.log( $('#'+d) ); // single quotes only
console.log( $("#"+d) ); // double quotes only

Your selector results like this, which is overkill with the quotes:

$('"#abc"') // -> it'll try to find  <div id='"#abc"'>

// In css, this would be the equivalent:
"#abc"{ /* Wrong */ } // instead of:
#abc{ /* Right */ }

Determining the path that a yum package installed to

Not in Linux at the moment, so can't double check, but I think it's:

rpm -ql ffmpeg

That should list all the files installed as part of the ffmpeg package.

MySQL 'create schema' and 'create database' - Is there any difference

Mysql documentation says : CREATE SCHEMA is a synonym for CREATE DATABASE as of MySQL 5.0.2.


this all goes back to an ANSI standard for SQL in the mid-80s.

That standard had a "CREATE SCHEMA" command, and it served to introduce multiple name spaces for table and view names. All tables and views were created within a "schema". I do not know whether that version defined some cross-schema access to tables and views, but I assume it did. AFAIR, no product (at least back then) really implemented it, that whole concept was more theory than practice.

OTOH, ISTR this version of the standard did not have the concept of a "user" or a "CREATE USER" command, so there were products that used the concept of a "user" (who then had his own name space for tables and views) to implement their equivalent of "schema".

This is an area where systems differ.

As far as administration is concerned, this should not matter too much, because here you have differences anyway.

As far as you look at application code, you "only" have to care about cases where one application accesses tables from multiple name spaces. AFAIK, all systems support a syntax ".", and for this it should not matter whether the name space is that of a user, a "schema", or a "database".

How to Display Selected Item in Bootstrap Button Dropdown Title

For example:

HTML:

<div class="dropdown">
  <button class="btn btn-default dropdown-toggle" type="button" data-toggle="dropdown">
     <BtnCaption>Select item</BtnCaption>
     <span class="caret"></span>   
  </button>
  <ul class="dropdown-menu">
     <li><a href="#">Option 1</a></li>
     <li><a href="#">Option 2</a></li>
     <li class="disabled"><a href="#">Option 3</a></li>   
  </ul> 
</div>

I use new element BtnCaption for changing only button's text.

Paste into $(document).ready(function () {} the following text

JavaScript:

    $(".dropdown-menu li:not(.disabled) a").click(function () {
        $(this).closest(".dropdown").find(".btn BtnCaption").text($(this).text()));
    });

:not(.disabled) don't allow use the disabled menu items

How can I simulate an anchor click via jquery?

In Javascript you can do like this

function submitRequest(buttonId) {
    if (document.getElementById(buttonId) == null
            || document.getElementById(buttonId) == undefined) {
        return;
    }
    if (document.getElementById(buttonId).dispatchEvent) {
        var e = document.createEvent("MouseEvents");
        e.initEvent("click", true, true);
        document.getElementById(buttonId).dispatchEvent(e);
    } else {
        document.getElementById(buttonId).click();
    }
}

and you can use it like

submitRequest("target-element-id");

Program to find prime numbers

There are some very optimal ways to implement the algorithm. But if you don't know much about maths and you simply follow the definition of prime as the requirement: a number that is only divisible by 1 and by itself (and nothing else), here's a simple to understand code for positive numbers.

public bool IsPrime(int candidateNumber)
{
    int fromNumber = 2;
    int toNumber = candidateNumber - 1;

    while(fromNumber <= toNumber)
    {
        bool isDivisible = candidateNumber % fromNumber == 0;
        if (isDivisible)
        {
            return false;
        }

        fromNumber++;
    }
    return true;
}

Since every number is divisible by 1 and by itself, we start checking from 2 onwards until the number immediately before itself. That's the basic reasoning.

Laravel - Route::resource vs Route::controller

RESTful Resource controller

A RESTful resource controller sets up some default routes for you and even names them.

Route::resource('users', 'UsersController');

Gives you these named routes:

Verb          Path                        Action  Route Name
GET           /users                      index   users.index
GET           /users/create               create  users.create
POST          /users                      store   users.store
GET           /users/{user}               show    users.show
GET           /users/{user}/edit          edit    users.edit
PUT|PATCH     /users/{user}               update  users.update
DELETE        /users/{user}               destroy users.destroy

And you would set up your controller something like this (actions = methods)

class UsersController extends BaseController {

    public function index() {}

    public function show($id) {}

    public function store() {}

}

You can also choose what actions are included or excluded like this:

Route::resource('users', 'UsersController', [
    'only' => ['index', 'show']
]);

Route::resource('monkeys', 'MonkeysController', [
    'except' => ['edit', 'create']
]);

API Resource controller

Laravel 5.5 added another method for dealing with routes for resource controllers. API Resource Controller acts exactly like shown above, but does not register create and edit routes. It is meant to be used for ease of mapping routes used in RESTful APIs - where you typically do not have any kind of data located in create nor edit methods.

Route::apiResource('users', 'UsersController');

RESTful Resource Controller documentation


Implicit controller

An Implicit controller is more flexible. You get routed to your controller methods based on the HTTP request type and name. However, you don't have route names defined for you and it will catch all subfolders for the same route.

Route::controller('users', 'UserController');

Would lead you to set up the controller with a sort of RESTful naming scheme:

class UserController extends BaseController {

    public function getIndex()
    {
        // GET request to index
    }

    public function getShow($id)
    {
        // get request to 'users/show/{id}'
    }

    public function postStore()
    {
        // POST request to 'users/store'
    }

}

Implicit Controller documentation


It is good practice to use what you need, as per your preference. I personally don't like the Implicit controllers, because they can be messy, don't provide names and can be confusing when using php artisan routes. I typically use RESTful Resource controllers in combination with explicit routes.

Child element click event trigger the parent click event

You need to use event.stopPropagation()

Live Demo

$('#childDiv').click(function(event){
    event.stopPropagation();
    alert(event.target.id);
});?

event.stopPropagation()

Description: Prevents the event from bubbling up the DOM tree, preventing any parent handlers from being notified of the event.

Javascript/jQuery detect if input is focused

Did you try:

$(this).is(':focus');

Take a look at Using jQuery to test if an input has focus it features some more examples

jquery can't get data attribute value

You can change the selector and data attributes as you wish!

 <select id="selectVehicle">
       <option value="1" data-year="2011">Mazda</option>
       <option value="2" data-year="2015">Honda</option>
       <option value="3" data-year="2008">Mercedes</option>
       <option value="4" data-year="2005">Toyota</option>
  </select>

$("#selectVehicle").change(function () {
     alert($(this).find(':selected').data("year"));
});

Here is the working example: https://jsfiddle.net/ed5axgvk/1/

SQL query for finding records where count > 1

I wouldn't recommend the HAVING keyword for newbies, it is essentially for legacy purposes.

I am not clear on what is the key for this table (is it fully normalized, I wonder?), consequently I find it difficult to follow your specification:

I would like to find all records for all users that have more than one payment per day with the same account number... Additionally, there should be a filter than only counts the records whose ZIP code is different.

So I've taken a literal interpretation.

The following is more verbose but could be easier to understand and therefore maintain (I've used a CTE for the table PAYMENT_TALLIES but it could be a VIEW:

WITH PAYMENT_TALLIES (user_id, zip, tally)
     AS
     (
      SELECT user_id, zip, COUNT(*) AS tally
        FROM PAYMENT
       GROUP 
          BY user_id, zip
     )
SELECT DISTINCT *
  FROM PAYMENT AS P
 WHERE EXISTS (
               SELECT * 
                 FROM PAYMENT_TALLIES AS PT
                WHERE P.user_id = PT.user_id
                      AND PT.tally > 1
              );

Android runOnUiThread explanation

If you already have the data "for (Parcelable currentHeadline : allHeadlines)," then why are you doing that in a separate thread?

You should poll the data in a separate thread, and when it's finished gathering it, then call your populateTables method on the UI thread:

private void populateTable() {
    runOnUiThread(new Runnable(){
        public void run() {
            //If there are stories, add them to the table
            for (Parcelable currentHeadline : allHeadlines) {
                addHeadlineToTable(currentHeadline);
            }
            try {
                dialog.dismiss();
            } catch (final Exception ex) {
                Log.i("---","Exception in thread");
            }
        }
    });
}

How to edit an Android app?

You would need to decompile the apk as Davis suggested, can use tools such as apkTool , then if you need to change the source code you would need other tools to do that.

You would then need to put the apk back together and sign it, if you don't have the original key used to sign the apk this means the new apk will have a different signature.

If the developer employed any obfuscation or other techniques to protect the app then it gets more complicated.

In short its a pretty complex and technical procedure, so if the developer is really just out of reach, its better to wait until he is in reach. And ask for the source code next time.

How to print a two dimensional array?

more simpler approach , use java 5 style for loop

Integer[][] twoDimArray = {{8, 9},{8, 10}};
        for (Integer[] array: twoDimArray){
            System.out.print(array[0] + " ,");
            System.out.println(array[1]);
        }

NULL values inside NOT IN clause

In A, 3 is tested for equality against each member of the set, yielding (FALSE, FALSE, TRUE, UNKNOWN). Since one of the elements is TRUE, the condition is TRUE. (It's also possible that some short-circuiting takes place here, so it actually stops as soon as it hits the first TRUE and never evaluates 3=NULL.)

In B, I think it is evaluating the condition as NOT (3 in (1,2,null)). Testing 3 for equality against the set yields (FALSE, FALSE, UNKNOWN), which is aggregated to UNKNOWN. NOT ( UNKNOWN ) yields UNKNOWN. So overall the truth of the condition is unknown, which at the end is essentially treated as FALSE.

Set "Homepage" in Asp.Net MVC

I tried the answer but it didn't worked for me. This is what i ended up doing:

Create a new controller DefaultController. In index action, i wrote one line redirect:

return Redirect("~/Default.aspx")

In RouteConfig.cs, change controller="Default" for the route.

 routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Default", action = "Index", id = UrlParameter.Optional }
        );

How can I connect to MySQL in Python 3 on Windows?

This is a quick tutorial on how to get Python 3.7 working with Mysql
Thanks to all from who I got answers to my questions
- hope this helps somebody someday.
----------------------------------------------------
My System:
Windows Version: Pro 64-bit

REQUIREMENTS.. download and install these first...
1. Download Xampp..
https://www.apachefriends.org/download.html
2. Download Python
https://www.python.org/downloads/windows/

--------------
//METHOD
--------------
Install xampp first after finished installing - install Python 3.7.
Once finished installing both - reboot your windows system.
Now start xampp and from the control panel - start the mysql server.
Confirm the versions by opening up CMD and in the terminal type

c:\>cd c:\xampp\mysql\bin

c:\xampp\mysql\bin>mysql -h localhost -v
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 2
Server version: 10.1.21-MariaDB mariadb.org binary distribution

Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.

This is to check the MYSQL version

c:\xampp\mysql\bin>python
Python 3.7.0b3 (v3.7.0b3:4e7efa9c6f, Mar 29 2018, 18:42:04) [MSC v.1913 64 bit (AMD64)] on win32

This is to check the Python version
Now that both have been confirmed type the following into the CMD...

c:\xampp\mysql\bin>pip install pymysql

After the install of pymysql is completed.
create a new file called "testconn.py" on your desktop or whereever for quick access.
Open this file with sublime or another text editor and put this into it.
Remember to change the settings to reflect your database.

#!/usr/bin/python
import pymysql
pymysql.install_as_MySQLdb() 

import MySQLdb
db = MySQLdb.connect(user="yourusernamehere",passwd="yourpasswordhere",host="yourhosthere",db="yourdatabasehere")
cursor = db.cursor()
cursor.execute("SELECT * from yourmysqltablehere")
data=cursor.fetchall()
for row in data :
    print (row)
db.close()

Now in your CMD - type

c:\Desktop>testconn.py

And thats it... your now fully connected from a python script to mysql...
Enjoy...

Send attachments with PHP Mail()?

After struggling for a while with badly formatted attachments, this is the code I used:

$email = new PHPMailer();
$email->From      = '[email protected]';
$email->FromName  = 'FromName';
$email->Subject   = 'Subject';
$email->Body      = 'Body';
$email->AddAddress( '[email protected]' );
$email->AddAttachment( "/path/to/filename.ext" , "filename.ext", 'base64', 'application/octet-stream' );
$email->Send();

How can I upload files asynchronously?

I've written this up in a Rails environment. It's only about five lines of JavaScript, if you use the lightweight jQuery-form plugin.

The challenge is in getting AJAX upload working as the standard remote_form_for doesn't understand multi-part form submission. It's not going to send the file data Rails seeks back with the AJAX request.

That's where the jQuery-form plugin comes into play.

Here’s the Rails code for it:

<% remote_form_for(:image_form, 
                   :url => { :controller => "blogs", :action => :create_asset }, 
                   :html => { :method => :post, 
                              :id => 'uploadForm', :multipart => true }) 
                                                                        do |f| %>
 Upload a file: <%= f.file_field :uploaded_data %>
<% end %>

Here’s the associated JavaScript:

$('#uploadForm input').change(function(){
 $(this).parent().ajaxSubmit({
  beforeSubmit: function(a,f,o) {
   o.dataType = 'json';
  },
  complete: function(XMLHttpRequest, textStatus) {
   // XMLHttpRequest.responseText will contain the URL of the uploaded image.
   // Put it in an image element you create, or do with it what you will.
   // For example, if you have an image elemtn with id "my_image", then
   //  $('#my_image').attr('src', XMLHttpRequest.responseText);
   // Will set that image tag to display the uploaded image.
  },
 });
});

And here’s the Rails controller action, pretty vanilla:

 @image = Image.new(params[:image_form])
 @image.save
 render :text => @image.public_filename

I’ve been using this for the past few weeks with Bloggity, and it’s worked like a champ.

How to convert from []byte to int in Go Programming

now := []byte{0xFF,0xFF,0xFF,0xFF}
nowBuffer := bytes.NewReader(now)
var  nowVar uint32
binary.Read(nowBuffer,binary.BigEndian,&nowVar)
fmt.Println(nowVar)
4294967295

Get today date in google appScript

Utilities.formatDate(new Date(), "GMT+1", "dd/MM/yyyy")

You can change the format by doing swapping the values.

  • dd = day(31)
  • MM = Month(12) - Case sensitive
  • yyyy = Year(2017)
function changeDate() {
    var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(GA_CONFIG);
    // You could use now Date(); on its own but it will not look nice.
    var date = Utilities.formatDate(new Date(), "GMT+1", "dd/MM/yyyy")
    var endDate = date
}

How to create a GUID/UUID using iOS

Reviewing the Apple Developer documentation I found the CFUUID object is available on the iPhone OS 2.0 and later.

CodeIgniter: 404 Page Not Found on Live Server

I was stuck with this approx a day i just rename filename "Filename" with capital letter and rename the controller class "Classname". and it solved the problem.

**class Myclass extends CI_Controller{}
save file: Myclass.php**

application/config/config.php

$config['base_url'] = '';

How can I change or remove HTML5 form validation default error messages?

I found a bug on Ankur answer and I've fixed it with this correction:

 <input type="text" pattern="[a-zA-Z]+"
    oninvalid="setCustomValidity('Plz enter on Alphabets ')"
    onchange="try{setCustomValidity('')}catch(e){}" />

The bug seen when you set an invalid input data, then correct the input and send the form. oops! you can't do this. I've tested it on firefox and chrome

How do I create a message box with "Yes", "No" choices and a DialogResult?

You can also use this variant with text strings, here's the complete changed code (Code from Mikael), tested in C# 2012:

// Variable
string MessageBoxTitle = "Some Title";
string MessageBoxContent = "Sure";

DialogResult dialogResult = MessageBox.Show(MessageBoxContent, MessageBoxTitle, MessageBoxButtons.YesNo);
if(dialogResult == DialogResult.Yes)
{
    //do something
}
else if (dialogResult == DialogResult.No)
{
    //do something else
}

You can after

.YesNo

insert a message icon

, MessageBoxIcon.Question

Alter table add multiple columns ms sql

You need to remove the brackets

ALTER TABLE Countries
ADD  
HasPhotoInReadyStorage  bit,
 HasPhotoInWorkStorage  bit,
 HasPhotoInMaterialStorage bit,
 HasText  bit;

SQL Server: Extract Table Meta-Data (description, fields and their data types)

I just finished a .net library with a few useful queries that return strongly typed C# objects for code gen/ t4 templates.

nuget SqlMeta

Project Site

github source

/// <summary>
    ///     Get All Table Names
    /// </summary>
    /// <returns></returns>
    public List<string> GetTableNames()
    {
        var sql = @"SELECT name
                    FROM dbo.sysobjects
                    WHERE xtype = 'U' 
                    AND name <> 'sysdiagrams'
                    order by name asc";

        return databaseWrapper.Call(connection => connection.Query<string>(
            sql: sql))
            .ToList();
    }

    /// <summary>
    ///     Get table info by schema and table or null for all
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="table"></param>
    /// <returns></returns>
    public List<SqlTableInfo> GetTableInfo(string schema = null, string table = null)
    {
        var result = new List<SqlTableInfo>();

        var sql = @"SELECT
                    c.TABLE_CATALOG AS [TableCatalog]
                ,   c.TABLE_SCHEMA AS [Schema]
                ,   c.TABLE_NAME AS [TableName]
                ,   c.COLUMN_NAME AS [ColumnName]
                ,   c.ORDINAL_POSITION AS [OrdinalPosition]
                ,   c.COLUMN_DEFAULT AS [ColumnDefault]
                ,   c.IS_NULLABLE AS [Nullable]
                ,   c.DATA_TYPE AS [DataType]
                ,   c.CHARACTER_MAXIMUM_LENGTH AS [CharacterMaxLength]
                ,   c.CHARACTER_OCTET_LENGTH AS [CharacterOctetLenth]
                ,   c.NUMERIC_PRECISION AS [NumericPrecision]
                ,   c.NUMERIC_PRECISION_RADIX AS [NumericPrecisionRadix]
                ,   c.NUMERIC_SCALE AS [NumericScale]
                ,   c.DATETIME_PRECISION AS [DatTimePrecision]
                ,   c.CHARACTER_SET_CATALOG AS [CharacterSetCatalog]
                ,   c.CHARACTER_SET_SCHEMA AS [CharacterSetSchema]
                ,   c.CHARACTER_SET_NAME AS [CharacterSetName]
                ,   c.COLLATION_CATALOG AS [CollationCatalog]
                ,   c.COLLATION_SCHEMA AS [CollationSchema]
                ,   c.COLLATION_NAME AS [CollationName]
                ,   c.DOMAIN_CATALOG AS [DomainCatalog]
                ,   c.DOMAIN_SCHEMA AS [DomainSchema]
                ,   c.DOMAIN_NAME AS [DomainName]
                ,   IsPrimaryKey = CONVERT(BIT, (SELECT
                            COUNT(*)
                        FROM    INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
                            ,   INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE cu
                        WHERE CONSTRAINT_TYPE = 'PRIMARY KEY'
                        AND tc.CONSTRAINT_NAME = cu.CONSTRAINT_NAME
                        AND tc.TABLE_NAME = c.TABLE_NAME
                        AND cu.TABLE_SCHEMA = c.TABLE_SCHEMA
                        AND cu.COLUMN_NAME = c.COLUMN_NAME)
                    )
                ,   IsIdentity = CONVERT(BIT, (SELECT
                            COUNT(*)
                        FROM sys.objects obj
                        INNER JOIN sys.COLUMNS col
                            ON obj.object_id = col.object_id
                        WHERE obj.type = 'U'
                        AND obj.Name = c.TABLE_NAME
                        AND col.Name = c.COLUMN_NAME
                        AND col.is_identity = 1)
                    )
                FROM INFORMATION_SCHEMA.COLUMNS c
                WHERE (@Schema IS NULL
                        OR c.TABLE_SCHEMA = @Schema)
                    AND (@TableName IS NULL
                        OR c.TABLE_NAME = @TableName)
                    ";

        var columns = databaseWrapper.Call(connection => connection.Query<SqlColumnInfo>(
            sql: sql,
            param: new { Schema = schema, TableName = table },
            commandType: CommandType.Text)
            .ToList());

        var refs = this.GetReferentialConstraints(table: table, schema: schema);

        foreach (var tableName in columns.Select(info => info.TableName).Distinct())
        {
            var tableColumns = columns.Where(info => info.TableName == tableName).ToList();
            var children = refs.Where(c => c.UniqueTableName == tableName).ToList();
            var parents = refs.Where(c => c.TableName == tableName).ToList();
            result.Add(new SqlTableInfo
            {
                TableName = tableName,
                Columns = tableColumns,
                ChildConstraints = children,
                ParentConstraints = parents
            });

        }

        return result;
    }

    public List<SqlReferentialConstraint> GetReferentialConstraints(string table = null, string schema = null)
    {
        //https://technet.microsoft.com/en-us/library/aa175805%28v=sql.80%29.aspx
        //https://technet.microsoft.com/en-us/library/Aa175805.312ron1%28l=en-us,v=sql.80%29.jpg
        //https://msdn.microsoft.com/en-us/library/ms186778.aspx

        var sql = @"
                    SELECT
                        KCU1.CONSTRAINT_NAME AS [ConstraintName]
                    ,   KCU1.TABLE_NAME AS [TableName]
                    ,   KCU1.COLUMN_NAME AS [ColumnName]
                    ,   KCU2.CONSTRAINT_NAME AS [UniqueConstraintName]
                    ,   KCU2.TABLE_NAME AS [UniqueTableName]
                    ,   KCU2.COLUMN_NAME AS [UniqueColumnName]
                    ,   RC.MATCH_OPTION AS [MatchOption]
                    ,   RC.UPDATE_RULE AS [UpdateRule]
                    ,   RC.DELETE_RULE AS [DeleteRule]
                    FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS RC
                    LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KCU1 ON KCU1.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG
                        AND KCU1.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA
                        AND KCU1.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
                    LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KCU2 ON KCU2.CONSTRAINT_CATALOG = RC.UNIQUE_CONSTRAINT_CATALOG
                        AND KCU2.CONSTRAINT_SCHEMA = RC.UNIQUE_CONSTRAINT_SCHEMA
                        AND KCU2.CONSTRAINT_NAME = RC.UNIQUE_CONSTRAINT_NAME
                    WHERE KCU1.ORDINAL_POSITION = KCU2.ORDINAL_POSITION
                            AND (@Table IS NULL
                                OR KCU1.TABLE_NAME = @Table
                                OR KCU2.TABLE_NAME = @Table)
                            AND (@Schema IS NULL
                                OR KCU1.TABLE_SCHEMA = @Schema
                                OR KCU2.TABLE_SCHEMA = @Schema)
                    ";

        return databaseWrapper.Call(connection => connection.Query<SqlReferentialConstraint>(
            sql: sql,
            param: new { Table = table, Schema = schema },
            commandType: CommandType.Text))
            .ToList();
    }

    /// <summary>
    ///     Get Primary Key Column by schema and table name
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="tableName"></param>
    /// <returns></returns>
    public string GetPrimaryKeyColumnName(string schema, string tableName)
    {
        var sql = @"SELECT
                    B.COLUMN_NAME
                FROM    INFORMATION_SCHEMA.TABLE_CONSTRAINTS A
                    ,   INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE B
                WHERE CONSTRAINT_TYPE = 'PRIMARY KEY'
                    AND A.CONSTRAINT_NAME = B.CONSTRAINT_NAME
                    AND A.TABLE_NAME = @TableName
                    AND A.TABLE_SCHEMA = @Schema";

        return databaseWrapper.Call(connection => connection.Query<string>(
            sql: sql,
            param: new { TableName = tableName, Schema = schema },
            commandType: CommandType.Text))
            .SingleOrDefault();
    }

    /// <summary>
    ///     Get Identity Column by table name
    /// </summary>
    /// <param name="tableName"></param>
    /// <returns></returns>
    public string GetIdentityColumnName(string tableName)
    {
        var sql = @"SELECT
                    c.Name
                FROM sys.objects o
                INNER JOIN sys.columns c ON o.object_id = c.object_id
                WHERE o.type = 'U'
                    AND c.is_identity = 1
                    AND o.Name = @TableName";

        return databaseWrapper.Call(connection => connection.Query<string>(
            sql: sql,
            param: new { TableName = tableName },
            commandType: CommandType.Text))
            .SingleOrDefault();
    }

    /// <summary>
    ///     Get All Stored Procedures by schema
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="procName"></param>
    /// <returns></returns>
    public List<SqlStoredProcedureInfo> GetStoredProcedureInfo(string schema = null, string procName = null)
    {
        var result = new List<SqlStoredProcedureInfo>();

        var sql = @"SELECT
                        SPECIFIC_NAME AS [Name]
                    ,   SPECIFIC_SCHEMA AS [Schema]
                    ,   Created AS [Created]
                    ,   LAST_ALTERED AS [LastAltered]
                    FROM INFORMATION_SCHEMA.ROUTINES
                    WHERE ROUTINE_TYPE = 'PROCEDURE'
                        AND (SPECIFIC_SCHEMA = @Schema
                            OR @Schema IS NULL)
                        AND (SPECIFIC_NAME = @ProcName
                            OR @ProcName IS NULL)
                        AND ((SPECIFIC_NAME NOT LIKE 'sp_%'
                                AND SPECIFIC_NAME NOT LIKE 'procUtils_GenerateClass'
                                AND (SPECIFIC_SCHEMA = @Schema
                                    OR @Schema IS NULL))
                            OR SPECIFIC_SCHEMA <> @Schema)";

        var sprocs = databaseWrapper.Call(connection => connection.Query<SqlStoredProcedureInfo>(
            sql: sql,
            param: new { Schema = schema, ProcName = procName },
            commandType: CommandType.Text).ToList());

        foreach (var s in sprocs)
        {
            s.Parameters = GetStoredProcedureInputParameters(sprocName: s.Name, schema: schema);
            s.ResultColumns = GetColumnInfoFromStoredProcResult(storedProcName: s.Name, schema: schema);
            result.Add(s);
        }

        return result;
    }

    /// <summary>
    ///     Get Column info from Stored procedure result set
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="storedProcName"></param>
    /// <returns></returns>
    public List<DataColumn> GetColumnInfoFromStoredProcResult(string schema, string storedProcName)
    {
        //this one actually needs to use the dataset because it has the only accurate information about columns and if they can be null or not.
        var sb = new StringBuilder();
        if (!String.IsNullOrEmpty(schema))
        {
            sb.Append(String.Format("exec [{0}].[{1}] ", schema, storedProcName));
        }
        else
        {
            sb.Append(String.Format("exec [{0}] ", storedProcName));
        }

        var prms = GetStoredProcedureInputParameters(schema, storedProcName);

        var count = 1;
        foreach (var param in prms)
        {
            sb.Append(String.Format("{0}=null", param.Name));
            if (count < prms.Count)
            {
                sb.Append(", ");
            }
            count++;
        }

        var ds = new DataSet();
        using (var sqlConnection = (SqlConnection)databaseWrapper.GetOpenDbConnection())
        {
            using (var sqlAdapter = new SqlDataAdapter(sb.ToString(), sqlConnection))
            {
                if (sqlConnection.State != ConnectionState.Open) sqlConnection.Open();

                sqlAdapter.SelectCommand.ExecuteReader(CommandBehavior.SchemaOnly);

                sqlConnection.Close();

                sqlAdapter.FillSchema(ds, SchemaType.Source, "MyTable");
            }
        }

        var list = new List<DataColumn>();
        if (ds.Tables.Count > 0)
        {
            list = ds.Tables["MyTable"].Columns.Cast<DataColumn>().ToList();
        }

        return list;
    }

    /// <summary>
    ///     Get the input parameters for a stored procedure
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="sprocName"></param>
    /// <returns></returns>
    public List<SqlParameterInfo> GetStoredProcedureInputParameters(string schema = null, string sprocName = null)
    {
        var sql = @"SELECT
                    SCHEMA_NAME(schema_id) AS [Schema]
                ,   P.Name AS Name
                ,   @ProcName AS ProcedureName
                ,   TYPE_NAME(P.user_type_id) AS [ParameterDataType]
                ,   P.max_length AS [MaxLength]
                ,   P.Precision AS [Precision]
                ,   P.Scale AS Scale
                ,   P.has_default_value AS HasDefaultValue
                ,   P.default_value AS DefaultValue
                ,   P.object_id AS ObjectId
                ,   P.parameter_id AS ParameterId
                ,   P.system_type_id AS SystemTypeId
                ,   P.user_type_id AS UserTypeId
                ,   P.is_output AS IsOutput
                ,   P.is_cursor_ref AS IsCursor
                ,   P.is_xml_document AS IsXmlDocument
                ,   P.xml_collection_id AS XmlCollectionId
                ,   P.is_readonly AS IsReadOnly
                FROM sys.objects AS SO
                INNER JOIN sys.parameters AS P ON SO.object_id = P.object_id
                WHERE SO.object_id IN (SELECT
                            object_id
                        FROM sys.objects
                        WHERE type IN ('P', 'FN'))
                    AND (SO.Name = @ProcName
                        OR @ProcName IS NULL)
                    AND (SCHEMA_NAME(schema_id) = @Schema
                        OR @Schema IS NULL)
                ORDER BY P.parameter_id ASC";

        var result = databaseWrapper.Call(connection => connection.Query<SqlParameterInfo>(
            sql: sql,
            param: new { Schema = schema, ProcName = sprocName },
            commandType: CommandType.Text))
            .ToList();

        return result;
    }

Foreign Key Metadata

What does it mean when a PostgreSQL process is "idle in transaction"?

As mentioned here: Re: BUG #4243: Idle in transaction it is probably best to check your pg_locks table to see what is being locked and that might give you a better clue where the problem lies.

how do you view macro code in access?

EDIT: Per Michael Dillon's answer, SaveAsText does save the commands in a macro without having to go through converting to VBA. I don't know what happened when I tested that, but it didn't produce useful text in the resulting file.

So, I learned something new today!

ORIGINAL POST: To expand the question, I wondered if there was a way to retrieve the contents of a macro from code, and it doesn't appear that there is (at least not in A2003, which is what I'm running).

There are two collections through which you can access stored Macros:

  CurrentDB.Containers("Scripts").Documents
  CurrentProject.AllMacros

The properties that Intellisense identifies for the two collections are rather different, because the collections are of different types. The first (i.e., traditional, pre-A2000 way) is via a documents collection, and the methods/properties/members of all documents are the same, i.e., not specific to Macros.

Likewise, the All... collections of CurrentProject return collections where the individual items are of type Access Object. The result is that Intellisense gives you methods/properties/members that may not exist for the particular document/object.

So far as I can tell, there is no way to programatically retrieve the contents of a macro.

This would stand to reason, as macros aren't of much use to anyone who would have the capability of writing code to examine them programatically.

But if you just want to evaluate what the macros do, one alternative would be to convert them to VBA, which can be done programmatically thus:

  Dim varItem As Variant
  Dim strMacroName As String

  For Each varItem In CurrentProject.AllMacros
    strMacroName = varItem.Name
    'Debug.Print strMacroName
    DoCmd.SelectObject acMacro, strMacroName, True
    DoCmd.RunCommand acCmdConvertMacrosToVisualBasic
    Application.SaveAsText acModule, "Converted Macro- " & strMacroName, _
      CurrentProject.Path & "\" & "Converted Macro- " & strMacroName & ".txt"
  Next varItem

Then you could use the resulting text files for whatever you needed to do.

Note that this has to be run interactively in Access because it uses DoCmd.RunCommand, and you have to click OK for each macro -- tedious for databases with lots of macros, but not too onerous for a normal app, which shouldn't have more than a handful of macros.

Running shell command and capturing the output

I would like to suggest simppl as an option for consideration. It is a module that is available via pypi: pip install simppl and was runs on python3.

simppl allows the user to run shell commands and read the output from the screen.

The developers suggest three types of use cases:

  1. The simplest usage will look like this:
    from simppl.simple_pipeline import SimplePipeline
    sp = SimplePipeline(start=0, end=100):
    sp.print_and_run('<YOUR_FIRST_OS_COMMAND>')
    sp.print_and_run('<YOUR_SECOND_OS_COMMAND>') ```

  1. To run multiple commands concurrently use:
    commands = ['<YOUR_FIRST_OS_COMMAND>', '<YOUR_SECOND_OS_COMMAND>']
    max_number_of_processes = 4
    sp.run_parallel(commands, max_number_of_processes) ```

  1. Finally, if your project uses the cli module, you can run directly another command_line_tool as part of a pipeline. The other tool will be run from the same process, but it will appear from the logs as another command in the pipeline. This enables smoother debugging and refactoring of tools calling other tools.
    from example_module import example_tool
    sp.print_and_run_clt(example_tool.run, ['first_number', 'second_nmber'], 
                                 {'-key1': 'val1', '-key2': 'val2'},
                                 {'--flag'}) ```

Note that the printing to STDOUT/STDERR is via python's logging module.


Here is a complete code to show how simppl works:

import logging
from logging.config import dictConfig

logging_config = dict(
    version = 1,
    formatters = {
        'f': {'format':
              '%(asctime)s %(name)-12s %(levelname)-8s %(message)s'}
        },
    handlers = {
        'h': {'class': 'logging.StreamHandler',
              'formatter': 'f',
              'level': logging.DEBUG}
        },
    root = {
        'handlers': ['h'],
        'level': logging.DEBUG,
        },
)
dictConfig(logging_config)

from simppl.simple_pipeline import SimplePipeline
sp = SimplePipeline(0, 100)
sp.print_and_run('ls')

Show two digits after decimal point in c++

This will be possible with setiosflags(ios::showpoint).

How can I compile a Java program in Eclipse without running it?

Try this in your console:

javac {$PathToYourProyect}/*

If you also need any external library, try:

javac -cp {$PathToYourLibrary}.jar {$PathToYourProyect}/*

Matplotlib scatterplot; colour as a function of a third variable

Sometimes you may need to plot color precisely based on the x-value case. For example, you may have a dataframe with 3 types of variables and some data points. And you want to do following,

  • Plot points corresponding to Physical variable 'A' in RED.
  • Plot points corresponding to Physical variable 'B' in BLUE.
  • Plot points corresponding to Physical variable 'C' in GREEN.

In this case, you may have to write to short function to map the x-values to corresponding color names as a list and then pass on that list to the plt.scatter command.

x=['A','B','B','C','A','B']
y=[15,30,25,18,22,13]

# Function to map the colors as a list from the input list of x variables
def pltcolor(lst):
    cols=[]
    for l in lst:
        if l=='A':
            cols.append('red')
        elif l=='B':
            cols.append('blue')
        else:
            cols.append('green')
    return cols
# Create the colors list using the function above
cols=pltcolor(x)

plt.scatter(x=x,y=y,s=500,c=cols) #Pass on the list created by the function here
plt.grid(True)
plt.show()

Coloring scatter plot as a function of x variable

Removing a non empty directory programmatically in C or C++

If you are using a POSIX compliant OS, you could use nftw() for file tree traversal and remove (removes files or directories). If you are in C++ and your project uses boost, it is not a bad idea to use the Boost.Filesystem as suggested by Manuel.

In the code example below I decided not to traverse symbolic links and mount points (just to avoid a grand removal:) ):

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

static int rmFiles(const char *pathname, const struct stat *sbuf, int type, struct FTW *ftwb)
{
    if(remove(pathname) < 0)
    {
        perror("ERROR: remove");
        return -1;
    }
    return 0;
}

int main(int argc, char *argv[])
{
    if (argc != 2)
    {
        fprintf(stderr,"usage: %s path\n",argv[0]);
        exit(1);
    }

    // Delete the directory and its contents by traversing the tree in reverse order, without crossing mount boundaries and symbolic links

    if (nftw(argv[1], rmFiles,10, FTW_DEPTH|FTW_MOUNT|FTW_PHYS) < 0)
    {
        perror("ERROR: ntfw");
        exit(1);
    }

    return 0;
}

Use Robocopy to copy only changed files?

Looks like /e option is what you need, it'll skip same files/directories.

robocopy c:\data c:\backup /e

If you run the command twice, you'll see the second round is much faster since it skips a lot of things.

Mask for an Input to allow phone numbers?

I Think the simplest solutions is to add ngx-mask

npm i --save ngx-mask

then you can do

<input type='text' mask='(000) 000-0000' >

OR

<p>{{ phoneVar | mask: '(000) 000-0000' }} </p>

Multiprocessing vs Threading Python

MULTIPROCESSING

  • Multiprocessing adds CPUs to increase computing power.
  • Multiple processes are executed concurrently.
  • Creation of a process is time-consuming and resource intensive.
  • Multiprocessing can be symmetric or asymmetric.
  • The multiprocessing library in Python uses separate memory space, multiple CPU cores, bypasses GIL limitations in CPython, child processes are killable (ex. function calls in program) and is much easier to use.
  • Some caveats of the module are a larger memory footprint and IPC’s a little more complicated with more overhead.

MULTITHREADING

  • Multithreading creates multiple threads of a single process to increase computing power.
  • Multiple threads of a single process are executed concurrently.
  • Creation of a thread is economical in both sense time and resource.
  • The multithreading library is lightweight, shares memory, responsible for responsive UI and is used well for I/O bound applications.
  • The module isn’t killable and is subject to the GIL.
  • Multiple threads live in the same process in the same space, each thread will do a specific task, have its own code, own stack memory, instruction pointer, and share heap memory.
  • If a thread has a memory leak it can damage the other threads and parent process.

Example of Multi-threading and Multiprocessing using Python

Python 3 has the facility of Launching parallel tasks. This makes our work easier.

It has for thread pooling and Process pooling.

The following gives an insight:

ThreadPoolExecutor Example

import concurrent.futures
import urllib.request

URLS = ['http://www.foxnews.com/',
        'http://www.cnn.com/',
        'http://europe.wsj.com/',
        'http://www.bbc.co.uk/',
        'http://some-made-up-domain.com/']

# Retrieve a single page and report the URL and contents
def load_url(url, timeout):
    with urllib.request.urlopen(url, timeout=timeout) as conn:
        return conn.read()

# We can use a with statement to ensure threads are cleaned up promptly
with concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor:
    # Start the load operations and mark each future with its URL
    future_to_url = {executor.submit(load_url, url, 60): url for url in URLS}
    for future in concurrent.futures.as_completed(future_to_url):
        url = future_to_url[future]
        try:
            data = future.result()
        except Exception as exc:
            print('%r generated an exception: %s' % (url, exc))
        else:
            print('%r page is %d bytes' % (url, len(data)))

ProcessPoolExecutor

import concurrent.futures
import math

PRIMES = [
    112272535095293,
    112582705942171,
    112272535095293,
    115280095190773,
    115797848077099,
    1099726899285419]

def is_prime(n):
    if n % 2 == 0:
        return False

    sqrt_n = int(math.floor(math.sqrt(n)))
    for i in range(3, sqrt_n + 1, 2):
        if n % i == 0:
            return False
    return True

def main():
    with concurrent.futures.ProcessPoolExecutor() as executor:
        for number, prime in zip(PRIMES, executor.map(is_prime, PRIMES)):
            print('%d is prime: %s' % (number, prime))

if __name__ == '__main__':
    main()

Awaiting multiple Tasks with different results

Given three tasks - FeedCat(), SellHouse() and BuyCar(), there are two interesting cases: either they all complete synchronously (for some reason, perhaps caching or an error), or they don't.

Let's say we have, from the question:

Task<string> DoTheThings() {
    Task<Cat> x = FeedCat();
    Task<House> y = SellHouse();
    Task<Tesla> z = BuyCar();
    // what here?
}

Now, a simple approach would be:

Task.WhenAll(x, y, z);

but ... that isn't convenient for processing the results; we'd typically want to await that:

async Task<string> DoTheThings() {
    Task<Cat> x = FeedCat();
    Task<House> y = SellHouse();
    Task<Tesla> z = BuyCar();

    await Task.WhenAll(x, y, z);
    // presumably we want to do something with the results...
    return DoWhatever(x.Result, y.Result, z.Result);
}

but this does lots of overhead and allocates various arrays (including the params Task[] array) and lists (internally). It works, but it isn't great IMO. In many ways it is simpler to use an async operation and just await each in turn:

async Task<string> DoTheThings() {
    Task<Cat> x = FeedCat();
    Task<House> y = SellHouse();
    Task<Tesla> z = BuyCar();

    // do something with the results...
    return DoWhatever(await x, await y, await z);
}

Contrary to some of the comments above, using await instead of Task.WhenAll makes no difference to how the tasks run (concurrently, sequentially, etc). At the highest level, Task.WhenAll predates good compiler support for async/await, and was useful when those things didn't exist. It is also useful when you have an arbitrary array of tasks, rather than 3 discreet tasks.

But: we still have the problem that async/await generates a lot of compiler noise for the continuation. If it is likely that the tasks might actually complete synchronously, then we can optimize this by building in a synchronous path with an asynchronous fallback:

Task<string> DoTheThings() {
    Task<Cat> x = FeedCat();
    Task<House> y = SellHouse();
    Task<Tesla> z = BuyCar();

    if(x.Status == TaskStatus.RanToCompletion &&
       y.Status == TaskStatus.RanToCompletion &&
       z.Status == TaskStatus.RanToCompletion)
        return Task.FromResult(
          DoWhatever(a.Result, b.Result, c.Result));
       // we can safely access .Result, as they are known
       // to be ran-to-completion

    return Awaited(x, y, z);
}

async Task Awaited(Task<Cat> a, Task<House> b, Task<Tesla> c) {
    return DoWhatever(await x, await y, await z);
}

This "sync path with async fallback" approach is increasingly common especially in high performance code where synchronous completions are relatively frequent. Note it won't help at all if the completion is always genuinely asynchronous.

Additional things that apply here:

  1. with recent C#, a common pattern is for the async fallback method is commonly implemented as a local function:

    Task<string> DoTheThings() {
        async Task<string> Awaited(Task<Cat> a, Task<House> b, Task<Tesla> c) {
            return DoWhatever(await a, await b, await c);
        }
        Task<Cat> x = FeedCat();
        Task<House> y = SellHouse();
        Task<Tesla> z = BuyCar();
    
        if(x.Status == TaskStatus.RanToCompletion &&
           y.Status == TaskStatus.RanToCompletion &&
           z.Status == TaskStatus.RanToCompletion)
            return Task.FromResult(
              DoWhatever(a.Result, b.Result, c.Result));
           // we can safely access .Result, as they are known
           // to be ran-to-completion
    
        return Awaited(x, y, z);
    }
    
  2. prefer ValueTask<T> to Task<T> if there is a good chance of things ever completely synchronously with many different return values:

    ValueTask<string> DoTheThings() {
        async ValueTask<string> Awaited(ValueTask<Cat> a, Task<House> b, Task<Tesla> c) {
            return DoWhatever(await a, await b, await c);
        }
        ValueTask<Cat> x = FeedCat();
        ValueTask<House> y = SellHouse();
        ValueTask<Tesla> z = BuyCar();
    
        if(x.IsCompletedSuccessfully &&
           y.IsCompletedSuccessfully &&
           z.IsCompletedSuccessfully)
            return new ValueTask<string>(
              DoWhatever(a.Result, b.Result, c.Result));
           // we can safely access .Result, as they are known
           // to be ran-to-completion
    
        return Awaited(x, y, z);
    }
    
  3. if possible, prefer IsCompletedSuccessfully to Status == TaskStatus.RanToCompletion; this now exists in .NET Core for Task, and everywhere for ValueTask<T>

How do I change the default index page in Apache?

You can also set DirectoryIndex in apache's httpd.conf file.

CentOS keeps this file in /etc/httpd/conf/httpd.conf Debian: /etc/apache2/apache2.conf

Open the file in your text editor and find the line starting with DirectoryIndex

To load landing.html as a default (but index.html if that's not found) change this line to read:

DirectoryIndex  landing.html index.html

HTML select drop-down with an input field

You can use input text with "list" attribute, which refers to the datalist of values.

_x000D_
_x000D_
<input type="text" name="city" list="cityname">_x000D_
    <datalist id="cityname">_x000D_
      <option value="Boston">_x000D_
      <option value="Cambridge">_x000D_
    </datalist>
_x000D_
_x000D_
_x000D_

This creates a free text input field that also has a drop-down to select predefined choices. Attribution for example and more information: https://www.w3.org/wiki/HTML/Elements/datalist

jQuery issue - #<an Object> has no method

I had this problem, or one that looked superficially similar, yesterday. It turned out that I wasn't being careful when mixing jQuery and prototype. I found several solutions at http://docs.jquery.com/Using_jQuery_with_Other_Libraries. I opted for

var $j = jQuery.noConflict();

but there are other reasonable options described there.

request exceeds the configured maxQueryStringLength when using [Authorize]

When an unauthorized request comes in, the entire request is URL encoded, and added as a query string to the request to the authorization form, so I can see where this may result in a problem given your situation.

According to MSDN, the correct element to modify to reset maxQueryStringLength in web.config is the <httpRuntime> element inside the <system.web> element, see httpRuntime Element (ASP.NET Settings Schema). Try modifying that element.

Understanding the main method of python

Python does not have a defined entry point like Java, C, C++, etc. Rather it simply executes a source file line-by-line. The if statement allows you to create a main function which will be executed if your file is loaded as the "Main" module rather than as a library in another module.

To be clear, this means that the Python interpreter starts at the first line of a file and executes it. Executing lines like class Foobar: and def foobar() creates either a class or a function and stores them in memory for later use.

Remove Elements from a HashSet while Iterating

Java 8 Collection has a nice method called removeIf that makes things easier and safer. From the API docs:

default boolean removeIf(Predicate<? super E> filter)
Removes all of the elements of this collection that satisfy the given predicate. 
Errors or runtime exceptions thrown during iteration or by the predicate 
are relayed to the caller.

Interesting note:

The default implementation traverses all elements of the collection using its iterator(). 
Each matching element is removed using Iterator.remove().

From: https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html#removeIf-java.util.function.Predicate-

Find and kill a process in one line using bash and regex

In bash, you should be able to do:

kill $(ps aux | grep '[p]ython csp_build.py' | awk '{print $2}')

Details on its workings are as follows:

  • The ps gives you the list of all the processes.
  • The grep filters that based on your search string, [p] is a trick to stop you picking up the actual grep process itself.
  • The awk just gives you the second field of each line, which is the PID.
  • The $(x) construct means to execute x then take its output and put it on the command line. The output of that ps pipeline inside that construct above is the list of process IDs so you end up with a command like kill 1234 1122 7654.

Here's a transcript showing it in action:

pax> sleep 3600 &
[1] 2225
pax> sleep 3600 &
[2] 2226
pax> sleep 3600 &
[3] 2227
pax> sleep 3600 &
[4] 2228
pax> sleep 3600 &
[5] 2229
pax> kill $(ps aux | grep '[s]leep' | awk '{print $2}')
[5]+  Terminated              sleep 3600
[1]   Terminated              sleep 3600
[2]   Terminated              sleep 3600
[3]-  Terminated              sleep 3600
[4]+  Terminated              sleep 3600

and you can see it terminating all the sleepers.


Explaining the grep '[p]ython csp_build.py' bit in a bit more detail:

When you do sleep 3600 & followed by ps -ef | grep sleep, you tend to get two processes with sleep in it, the sleep 3600 and the grep sleep (because they both have sleep in them, that's not rocket science).

However, ps -ef | grep '[s]leep' won't create a process with sleep in it, it instead creates grep '[s]leep' and here's the tricky bit: the grep doesn't find it because it's looking for the regular expression "any character from the character class [s] (which is s) followed by leep.

In other words, it's looking for sleep but the grep process is grep '[s]leep' which doesn't have sleep in it.

When I was shown this (by someone here on SO), I immediately started using it because

  • it's one less process than adding | grep -v grep; and
  • it's elegant and sneaky, a rare combination :-)

What is the maximum possible length of a .NET string?

The theoretical limit may be 2,147,483,647, but the practical limit is nowhere near that. Since no single object in a .NET program may be over 2GB and the string type uses UTF-16 (2 bytes for each character), the best you could do is 1,073,741,823, but you're not likely to ever be able to allocate that on a 32-bit machine.

This is one of those situations where "If you have to ask, you're probably doing something wrong."

How do you specifically order ggplot2 x axis instead of alphabetical order?

The accepted answer offers a solution which requires changing of the underlying data frame. This is not necessary. One can also simply factorise within the aes() call directly or create a vector for that instead.

This is certainly not much different than user Drew Steen's answer, but with the important difference of not changing the original data frame.

level_order <- c('virginica', 'versicolor', 'setosa') #this vector might be useful for other plots/analyses

ggplot(iris, aes(x = factor(Species, level = level_order), y = Petal.Width)) + geom_col()

or

level_order <- factor(iris$Species, level = c('virginica', 'versicolor', 'setosa'))

ggplot(iris, aes(x = level_order, y = Petal.Width)) + geom_col()

or
directly in the aes() call without a pre-created vector:

ggplot(iris, aes(x = factor(Species, level = c('virginica', 'versicolor', 'setosa')), y = Petal.Width)) + geom_col()

that's for the first version

increase font size of hyperlink text html

You can do like this:

a {font-size: 100px}

Try avoid using font tag because it's deprecated. Use CSS like above instead. You can give your anchors specific class and apply any style for them.

Are PDO prepared statements sufficient to prevent SQL injection?

No this is not enough (in some specific cases)! By default PDO uses emulated prepared statements when using MySQL as a database driver. You should always disable emulated prepared statements when using MySQL and PDO:

$dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);

Another thing that always should be done it set the correct encoding of the database:

$dbh = new PDO('mysql:dbname=dbtest;host=127.0.0.1;charset=utf8', 'user', 'pass');

Also see this related question: How can I prevent SQL injection in PHP?

Also note that that only is about the database side of the things you would still have to watch yourself when displaying the data. E.g. by using htmlspecialchars() again with the correct encoding and quoting style.

Create a file if it doesn't exist

I think this should work:

#open file for reading
fn = input("Enter file to open: ")
try:
    fh = open(fn,'r')
except:
# if file does not exist, create it
    fh = open(fn,'w')

Also, you incorrectly wrote fh = open ( fh, "w") when the file you wanted open was fn

What is the purpose and uniqueness SHTML?

SHTML is a file extension that lets the web server know the file should be processed as using Server Side Includes (SSI).

(HTML is...you know what it is, and DHTML is Microsoft's name for Javascript+HTML+CSS or something).

You can use SSI to include a common header and footer in your pages, so you don't have to repeat code as much. Changing one included file updates all of your pages at once. You just put it in your HTML page as per normal.

It's embedded in a standard XML comment, and looks like this:

<!--#include virtual="top.shtml" -->

It's been largely superseded by other mechanisms, such as PHP includes, but some hosting packages still support it and nothing else.

You can read more in this Wikipedia article.

Is there a way to make a DIV unselectable?

Make sure that you set position explicitly as absolute or relative for z-index to work for selection. I had a similar issue and this solved it for me.

Case-Insensitive List Search

I realise this is an old post, but just in case anyone else is looking, you can use Contains by providing the case insensitive string equality comparer like so:

using System.Linq;

// ...

if (testList.Contains(keyword, StringComparer.OrdinalIgnoreCase))
{
    Console.WriteLine("Keyword Exists");
}

This has been available since .net 2.0 according to msdn.

Save PHP variables to a text file

Okay, so I needed a solution to this, and I borrowed heavily from the answers to this question and made a library: https://github.com/rahuldottech/varDx (Licensed under the MIT license).

It uses serialize() and unserialize() and writes data to a file. It can read and write multiple objects/variables/whatever to and from the same file.

Usage:

<?php
require 'varDx.php';
$dx = new \varDx\cDX; //create an object
$dx->def('file.dat'); //define data file
$val1 = "this is a string";
$dx->write('data1', $val1); //writes key to file
echo $dx->read('data1'); //returns key value from file

See the github page for more information. It has functions to read, write, check, modify and delete data.

New og:image size for Facebook share?

The aspect ratio for a Facebook post image is 41:20.

To find the appropriate widths and height for your photo, you can use the Aspect Ratio Calculator.

Here you can select different ratios under “Common ratios:” which includes the option “1200 x 630 (Facebook)". So if the width of your photo is 1800, plug that number into the “W2” slot and it will tell you what the respective height should be.

Is there a sleep function in JavaScript?

function sleep(delay) {
    var start = new Date().getTime();
    while (new Date().getTime() < start + delay);
}

This code blocks for the specified duration. This is CPU hogging code. This is different from a thread blocking itself and releasing CPU cycles to be utilized by another thread. No such thing is going on here. Do not use this code, it's a very bad idea.

How to get Real IP from Visitor?

Proxies may send a HTTP_X_FORWARDED_FOR header but even that is optional.

Also keep in mind that visitors may share IP addresses; University networks, large companies and third-world/low-budget ISPs tend to share IPs over many users.

add allow_url_fopen to my php.ini using .htaccess

If your host is using suPHP, you can try creating a php.ini file in the same folder as the script and adding:

allow_url_fopen = On

(you can determine this by creating a file and checking which user it was created under: if you, it's suPHP, if "apache/nobody" or not you, then it's a normal PHP mode. You can also make a script

<?php
echo `id`;
?>

To give the same information, assuming shell_exec is not a disabled function)

Nesting CSS classes

Not possible with vanilla CSS. However you can use something like:

Sass makes CSS fun again. Sass is an extension of CSS3, adding nested rules, variables, mixins, selector inheritance, and more. It’s translated to well-formatted, standard CSS using the command line tool or a web-framework plugin.

Or

Rather than constructing long selector names to specify inheritance, in Less you can simply nest selectors inside other selectors. This makes inheritance clear and style sheets shorter.

Example:

#header {
  color: red;
  a {
    font-weight: bold;
    text-decoration: none;
  }
}

CSS table td width - fixed, not flexible

It is not only the table cell which is growing, the table itself can grow, too. To avoid this you can assign a fixed width to the table which in return forces the cell width to be respected:

table {
  table-layout: fixed;
  width: 120px; /* Important */
}
td {
  width: 30px;
}

(Using overflow: hidden and/or text-overflow: ellipsis is optional but highly recommended for a better visual experience)

So if your situation allows you to assign a fixed width to your table, this solution might be a better alternative to the other given answers (which do work with or without a fixed width)

Can overridden methods differ in return type?

class Phone {
    public Phone getMsg() {
        System.out.println("phone...");
        return new Phone();
    }
}

class Samsung extends Phone{
    @Override
    public Samsung getMsg() {
        System.out.println("samsung...");
        return new Samsung();
    }
    
    public static void main(String[] args) {
        Phone p=new Samsung();
        p.getMsg();
    }
}

CSS getting text in one line rather than two

The best way to use is white-space: nowrap; This will align the text to one line.

Angular 2 change event on every keypress

What you're looking for is

<input type="text" [(ngModel)]="mymodel" (keyup)="valuechange()" />
{{mymodel}}

Then do whatever you want with the data by accessing the bound this.mymodel in your .ts file.

Change onClick attribute with javascript

Using Jquery instead of Javascript, use 'attr' property instead of 'setAttribute'

like

$('buttonLED'+id).attr('onclick','writeLED(1,1)')

How do you make websites with Java?

Also be advised, that while Java is in general very beginner friendly, getting into JavaEE, Servlets, Facelets, Eclipse integration, JSP and getting everything in Tomcat up and running is not. Certainly not the easiest way to build a website and probably way overkill for most things.

On top of that you may need to host your website yourself, because most webspace providers don't provide Servlet Containers. If you just want to check it out for fun, I would try Ruby or Python, which are much more cooler things to fiddle around with. But anyway, to provide at least something relevant to the question, here's a nice Servlet tutorial: link

How to remove a column from an existing table?

The question is, can you only delete a column from an unexisting table ;-)

BEGIN TRANSACTION

IF exists (SELECT * FROM  sys.columns c 
INNER JOIN  sys.objects t ON (c.[object_id] = t.[object_id])
WHERE t.[object_id] = OBJECT_ID(N'[dbo].[MyTable]')
AND c.[name] = 'ColumnName')
    BEGIN TRY
        ALTER TABLE [dbo].[MyTable] DROP COLUMN ColumnName
    END TRY
    BEGIN CATCH
        print 'FAILED!'
    END CATCH
ELSE
    BEGIN 
        SELECT ERROR_NUMBER() AS ErrorNumber;
        print 'NO TABLE OR COLUMN FOUND !'
    END 

COMMIT  

How to get Map data using JDBCTemplate.queryForMap

To add to @BrianBeech's answer, this is even more trimmed down in java 8:

jdbcTemplate.query("select string1,string2 from table where x=1", (ResultSet rs) -> {
    HashMap<String,String> results = new HashMap<>();
    while (rs.next()) {
        results.put(rs.getString("string1"), rs.getString("string2"));
    }
    return results;
});

How to convert SQL Server's timestamp column to datetime format

After impelemtation of conversion to integer CONVERT(BIGINT, [timestamp]) as Timestamp I've got the result like

446701117 446701118 446701119 446701120 446701121 446701122 446701123 446701124 446701125 446701126

Yes, this is not a date and time, It's serial numbers

printf() prints whole array

But still, the memory address for each letter in this address is different.

Memory address is different but as its array of characters they are sequential. When you pass address of first element and use %s, printf will print all characters starting from given address until it finds '\0'.

TypeError: 'str' object cannot be interpreted as an integer

I'm guessing you're running python3, in which input(prompt) returns a string. Try this.

x=int(input('prompt'))
y=int(input('prompt'))

Golang read request body

I could use the GetBody from Request package.

Look this comment in source code from request.go in net/http:

GetBody defines an optional func to return a new copy of Body. It is used for client requests when a redirect requires reading the body more than once. Use of GetBody still requires setting Body. For server requests it is unused."

GetBody func() (io.ReadCloser, error)

This way you can get the body request without make it empty.

Sample:

getBody := request.GetBody
copyBody, err := getBody()
if err != nil {
    // Do something return err
}
http.DefaultClient.Do(request)

How can I add an ampersand for a value in a ASP.net/C# app config file value

Have you tried this?

<appSettings>  
  <add key="myurl" value="http://www.myurl.com?&amp;cid=&amp;sid="/>
<appSettings>

Check if an element is a child of a parent

If you are only interested in the direct parent, and not other ancestors, you can just use parent(), and give it the selector, as in target.parent('div#hello').

Example: http://jsfiddle.net/6BX9n/

function fun(evt) {
    var target = $(evt.target);    
    if (target.parent('div#hello').length) {
        alert('Your clicked element is having div#hello as parent');
    }
}

Or if you want to check to see if there are any ancestors that match, then use .parents().

Example: http://jsfiddle.net/6BX9n/1/

function fun(evt) {
    var target = $(evt.target);    
    if (target.parents('div#hello').length) {
        alert('Your clicked element is having div#hello as parent');
    }
}

Making sure at least one checkbox is checked

Vanilla JS:

var checkboxes = document.getElementsByClassName('activityCheckbox'); // puts all your checkboxes in a variable

function activitiesReset() {
    var checkboxesChecked = function () { // if a checkbox is checked, function ends and returns true. If all checkboxes have been iterated through (which means they are all unchecked), returns false.
        for (var i = 0; i < checkboxes.length; i++) {
            if (checkboxes[i].checked) {
                return true;
            }
        }
        return false;
    }
    error[2].style.display = 'none'; // an array item specific to my project - it's a red label which says 'Please check a checkbox!'. Here its display is set to none, so the initial non-error label is visible instead. 
        if (submitCounter > 0 && checkboxesChecked() === false) { // if a form submit has been attempted, and if all checkboxes are unchecked
            error[2].style.display = 'block'; // red error label is now visible.
        }
}

for (var i=0; i<checkboxes.length; i++) {  // whenever a checkbox is checked or unchecked, activitiesReset runs.
    checkboxes[i].addEventListener('change', activitiesReset);
}


Explanation:
Once a form submit has been attempted, this will update your checkbox section's label to notify the user to check a checkbox if he/she hasn't yet. If no checkboxes are checked, a hidden 'error' label is revealed prompting the user to 'Please check a checkbox!'. If the user checks at least one checkbox, the red label is instantaneously hidden again, revealing the original label. If the user again un-checks all checkboxes, the red label returns in real-time. This is made possible by JavaScript's onchange event (written as .addEventListener('change', function(){});

Bash Script : what does #!/bin/bash mean?

In bash script, what does #!/bin/bash at the 1st line mean ?

In Linux system, we have shell which interprets our UNIX commands. Now there are a number of shell in Unix system. Among them, there is a shell called bash which is very very common Linux and it has a long history. This is a by default shell in Linux.

When you write a script (collection of unix commands and so on) you have a option to specify which shell it can be used. Generally you can specify which shell it wold be by using Shebang(Yes that's what it's name).

So if you #!/bin/bash in the top of your scripts then you are telling your system to use bash as a default shell.

Now coming to your second question :Is there a difference between #!/bin/bash and #!/bin/sh ?

The answer is Yes. When you tell #!/bin/bash then you are telling your environment/ os to use bash as a command interpreter. This is hard coded thing.

Every system has its own shell which the system will use to execute its own system scripts. This system shell can be vary from OS to OS(most of the time it will be bash. Ubuntu recently using dash as default system shell). When you specify #!/bin/sh then system will use it's internal system shell to interpreting your shell scripts.

Visit this link for further information where I have explained this topic.

Hope this will eliminate your confusions...good luck.

String.equals versus ==

equals() function is a method of Object class which should be overridden by programmer. String class overrides it to check if two strings are equal i.e. in content and not reference.

== operator checks if the references of both the objects are the same.

Consider the programs

String abc = "Awesome" ;
String xyz =  abc;

if(abc == xyz)
     System.out.println("Refers to same string");

Here the abc and xyz, both refer to same String "Awesome". Hence the expression (abc == xyz) is true.

String abc = "Hello World";
String xyz = "Hello World";

if(abc == xyz)
    System.out.println("Refers to same string");
else
    System.out.println("Refers to different strings");

if(abc.equals(xyz))
     System.out.prinln("Contents of both strings are same");
else
     System.out.prinln("Contents of strings are different");

Here abc and xyz are two different strings with the same content "Hello World". Hence here the expression (abc == xyz) is false where as (abc.equals(xyz)) is true.

Hope you understood the difference between == and <Object>.equals()

Thanks.

Error: expected type-specifier before 'ClassName'

For future people struggling with a similar problem, the situation is that the compiler simply cannot find the type you are using (even if your Intelisense can find it).

This can be caused in many ways:

  • You forgot to #include the header that defines it.
  • Your inclusion guards (#ifndef BLAH_H) are defective (your #ifndef BLAH_H doesn't match your #define BALH_H due to a typo or copy+paste mistake).
  • Your inclusion guards are accidentally used twice (two separate files both using #define MYHEADER_H, even if they are in separate directories)
  • You forgot that you are using a template (eg. new Vector() should be new Vector<int>())
  • The compiler is thinking you meant one scope when really you meant another (For example, if you have NamespaceA::NamespaceB, AND a <global scope>::NamespaceB, if you are already within NamespaceA, it'll look in NamespaceA::NamespaceB and not bother checking <global scope>::NamespaceB) unless you explicitly access it.
  • You have a name clash (two entities with the same name, such as a class and an enum member).

To explicitly access something in the global namespace, prefix it with ::, as if the global namespace is a namespace with no name (e.g. ::MyType or ::MyNamespace::MyType).

ASP.NET - How to write some html in the page? With Response.Write?

why don't you give LiteralControl a try?

 myLitCtrl.Text="<h2><p>Notify:</p> Alert</h2>";

Postgresql query between date ranges

SELECT user_id 
FROM user_logs 
WHERE login_date BETWEEN '2014-02-01' AND '2014-03-01'

Between keyword works exceptionally for a date. it assumes the time is at 00:00:00 (i.e. midnight) for dates.

val() doesn't trigger change() in jQuery

onchange only fires when the user types into the input and then the input loses focus.

You can manually call the onchange event using after setting the value:

$("#mytext").change(); // someObject.onchange(); in standard JS

Alternatively, you can trigger the event using:

$("#mytext").trigger("change");

How do you get the current time of day?

DateTime.Now.TimeOfDay

or

DateTime.Now.ToShortTimeString()

Angular 4 HttpClient Query Parameters

search property of type URLSearchParams in RequestOptions class is deprecated in angular 4. Instead, you should use params property of type URLSearchParams.

Dividing two integers to produce a float result

Cast the operands to floats:

float ans = (float)a / (float)b;

"Automatic" vs "Automatic (Delayed start)"

In short, services set to Automatic will start during the boot process, while services set to start as Delayed will start shortly after boot.

Starting your service Delayed improves the boot performance of your server and has security benefits which are outlined in the article Adriano linked to in the comments.

Update: "shortly after boot" is actually 2 minutes after the last "automatic" service has started, by default. This can be configured by a registry key, according to Windows Internals and other sources (3,4).

The registry keys of interest (At least in some versions of windows) are:

  • HKLM\SYSTEM\CurrentControlSet\services\<service name>\DelayedAutostart will have the value 1 if delayed, 0 if not.
  • HKLM\SYSTEM\CurrentControlSet\services\AutoStartDelay or HKLM\SYSTEM\CurrentControlSet\Control\AutoStartDelay (on Windows 10): decimal number of seconds to wait, may need to create this one. Applies globally to all Delayed services.

Bootstrap-select - how to fire event on change

My implementation

import $ from 'jquery';

$(document).ready(() => {
  $('#whatDescribesYouSelectInput').on('change', (e) => {
    if (e.target.value === 'Other') {
      $('#whatDescribesYouOtherInput').attr('type', 'text');
      $('#specifyLabel').show();
    } else {
      $('#whatDescribesYouOtherInput').attr('type', 'hidden');
      $('#specifyLabel').hide();
    }
  });
});

Detect if a browser in a mobile device (iOS/Android phone/tablet) is used

I know this is an old thread but I thought this might help someone:

Mobile devices have greater height than width, in contrary, computers have greater width than height. For example:

@media all and (max-width: 320px) and (min-height: 320px)

so that would have to be done for every width i guess.

Which @NotNull Java annotation should I use?

I use the IntelliJ one, because I'm mostly concerned with IntelliJ flagging things that might produce a NPE. I agree that it's frustrating not having a standard annotation in the JDK. There's talk of adding it, it might make it into Java 7. In which case there will be one more to choose from!

Close popup window

For such a seemingly simple thing this can be a royal pain in the butt! I found a solution that works beautifully (class="video-close" is obviously particular to this button and optional)

 <a href="javascript:window.open('','_self').close();" class="video-close">Close this window</a>

AngularJS: How to clear query parameters in the URL?

If you want to move to another URL and clear the query parameters just use:

$location.path('/my/path').search({});

"date(): It is not safe to rely on the system's timezone settings..."

For docker user: Create a local timezone.ini file in your project, set up the config in docker-compose.yml,

    volumes:
        - "./docker/config/timezone.ini:/usr/local/etc/php/conf.d/timezone.ini"

timezone.ini

    date.timezone=Australia/Sydney

Swift - Split string over multiple lines

I tried several ways but found an even better solution: Just use a "Text View" element. It's text shows up multiple lines automatically! Found here: UITextField multiple lines

Using str_replace so that it only acts on the first match?

For a string

$string = 'OOO.OOO.OOO.S';
$search = 'OOO';
$replace = 'B';

//replace ONLY FIRST occurance of "OOO" with "B"
    $string = substr_replace($string,$replace,0,strlen($search));
    //$string => B.OOO.OOO.S

//replace ONLY LAST occurance of "OOOO" with "B"
    $string = substr_replace($string,$replace,strrpos($string,$search),strlen($search)) 
    //$string => OOO.OOO.B.S

    //replace ONLY LAST occurance of "OOOO" with "B"
    $string = strrev(implode(strrev($replace),explode(strrev($search),strrev($string),2)))
    //$string => OOO.OOO.B.S

For a single character

$string[strpos($string,$search)] = $replace;


//EXAMPLE

$string = 'O.O.O.O.S';
$search = 'O';
$replace = 'B';

//replace ONLY FIRST occurance of "O" with "B" 
    $string[strpos($string,$search)] = $replace;  
    //$string => B.O.O.O.S

//replace ONLY LAST occurance of "O" with "B" 
    $string[strrpos($string,$search)] = $replace; 
    // $string => B.O.O.B.S

Enums in Javascript with ES6

If you don't need pure ES6 and can use Typescript, it has a nice enum:

https://www.typescriptlang.org/docs/handbook/enums.html

CSS On hover show another element

It is indeed possible with the following code

 <div href="#" id='a'>
     Hover me
 </div>

<div id='b'>
    Show me
</div>

and css

#a {
  display: block;
}

#a:hover + #b {
  display:block;
}

#b {
  display:none;
  }

Now by hovering on element #a shows element #b.

Function to calculate R2 (R-squared) in R

Not sure why this isn't implemented directly in R, but this answer is essentially the same as Andrii's and Wordsforthewise, I just turned into a function for the sake of convenience if somebody uses it a lot like me.

r2_general <-function(preds,actual){ 
  return(1- sum((preds - actual) ^ 2)/sum((actual - mean(actual))^2))
}

How to get the current time as datetime

You can use Swift4 or Swift 5 bellow like:

let date = Date()
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let current_date = dateFormatter.string(from: date)
print("current_date-->",current_date)

output like:

2020-03-02

Drop all the tables, stored procedures, triggers, constraints and all the dependencies in one sql statement

To remove all objects in oracle :

1) Dynamic

DECLARE
CURSOR IX IS
SELECT * FROM ALL_OBJECTS WHERE OBJECT_TYPE ='TABLE' 
AND OWNER='SCHEMA_NAME';
 CURSOR IY IS
 SELECT * FROM ALL_OBJECTS WHERE OBJECT_TYPE 
IN ('SEQUENCE',
'PROCEDURE',
'PACKAGE',
'FUNCTION',
'VIEW') AND  OWNER='SCHEMA_NAME';
 CURSOR IZ IS
 SELECT * FROM ALL_OBJECTS WHERE OBJECT_TYPE IN ('TYPE') AND  OWNER='SCHEMA_NAME';
BEGIN
 FOR X IN IX LOOP
   EXECUTE IMMEDIATE('DROP '||X.OBJECT_TYPE||' '||X.OBJECT_NAME|| ' CASCADE CONSTRAINT');
 END LOOP;
 FOR Y IN IY LOOP
   EXECUTE IMMEDIATE('DROP '||Y.OBJECT_TYPE||' '||Y.OBJECT_NAME);
 END LOOP;
 FOR Z IN IZ LOOP
   EXECUTE IMMEDIATE('DROP '||Z.OBJECT_TYPE||' '||Z.OBJECT_NAME||' FORCE ');
 END LOOP;
END;
/

2)Static

    SELECT 'DROP TABLE "' || TABLE_NAME || '" CASCADE CONSTRAINTS;' FROM user_tables
        union ALL
        select 'drop '||object_type||' '|| object_name || ';' from user_objects 
        where object_type in ('VIEW','PACKAGE','SEQUENCE', 'PROCEDURE', 'FUNCTION')
        union ALL
        SELECT 'drop '
        ||object_type
        ||' '
        || object_name
        || ' force;'
        FROM user_objects
        WHERE object_type IN ('TYPE');

What is the difference between SAX and DOM?

Here in simpler words:

DOM

  • Tree model parser (Object based) (Tree of nodes).

  • DOM loads the file into the memory and then parse- the file.

  • Has memory constraints since it loads the whole XML file before parsing.

  • DOM is read and write (can insert or delete nodes).

  • If the XML content is small, then prefer DOM parser.

  • Backward and forward search is possible for searching the tags and evaluation of the information inside the tags. So this gives the ease of navigation.

  • Slower at run time.

SAX

  • Event based parser (Sequence of events).

  • SAX parses the file as it reads it, i.e. parses node by node.

  • No memory constraints as it does not store the XML content in the memory.

  • SAX is read only i.e. can’t insert or delete the node.

  • Use SAX parser when memory content is large.

  • SAX reads the XML file from top to bottom and backward navigation is not possible.

  • Faster at run time.

How do I break out of nested loops in Java?

If you don't like breaks and gotos, you can use a "traditional" for loop instead the for-in, with an extra abort condition:

int a, b;
bool abort = false;
for (a = 0; a < 10 && !abort; a++) {
    for (b = 0; b < 10 && !abort; b++) {
        if (condition) {
            doSomeThing();
            abort = true;
        }
    }
}

How to play a local video with Swift?

Sure you can use Swift!

1. Adding the video file

Add the video (lets call it video.m4v) to your Xcode project

2. Checking your video is into the Bundle

Open the Project Navigator cmd + 1

Then select your project root > your Target > Build Phases > Copy Bundle Resources.

Your video MUST be here. If it's not, then you should add it using the plus button

enter image description here

3. Code

Open your View Controller and write this code.

import UIKit
import AVKit
import AVFoundation

class ViewController: UIViewController {

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        playVideo()
    }

    private func playVideo() {
        guard let path = Bundle.main.path(forResource: "video", ofType:"m4v") else {
            debugPrint("video.m4v not found")
            return
        }
        let player = AVPlayer(url: URL(fileURLWithPath: path))
        let playerController = AVPlayerViewController()
        playerController.player = player
        present(playerController, animated: true) {
            player.play()
        }
    }
}

How to correctly assign a new string value?

The two structs are different. When you initialize the first struct, about 40 bytes of memory are allocated. When you initialize the second struct, about 10 bytesof memory are allocated. (Actual amount is architecture dependent)

You can use the string literals (string constants) to initalize character arrays. This is why

person p = {"John", "Doe",30};

works in the first example.

You cannot assign (in the conventional sense) a string in C.

The string literals you have ("John") are loaded into memory when your code executes. When you initialize an array with one of these literals, then the string is copied into a new memory location. In your second example, you are merely copying the pointer to (location of) the string literal. Doing something like:

char* string = "Hello";
*string = 'C'

might cause compile or runtime errors (I am not sure.) It is a bad idea because you are modifying the literal string "Hello" which, for example on a microcontroler, could be located in read-only memory.

Bootstrap - How to add a logo to navbar class?

I found a solution on another thread that works - use the pull-left class:

 <a href="#" class="pull-left"><img src="/path/to/image.png"></a> 

Thanks to Michael in this thread:

Bootstrap - How to add a logo to navbar class?

How do I get the logfile from an Android device?

For those not interested in USB debugging or using adb there is an easier solution. In Android 6 (Not sure about prior version) there is an option under developer tools: Take Bug Report

Clicking this option will prepare a bug report and prompt you to save it to drive or have it sent in email.

I found this to be the easiest way to get logs. I don't like to turn on USB debugging.

How to toggle boolean state of react component?

You should use this.state.check instead of check.value here:

this.setState({check: !this.state.check})

But anyway it is bad practice to do it this way. Much better to move it to separate method and don't write callbacks directly in markup.

Define a global variable in a JavaScript function

There are three types of scope in JavaScript:

  • Global Scoop: where the variable is available through the code.
  • Block Scoop: where the variable is available inside a certain area like a function.
  • Local Scoop: where the variable is available in more certain areas, like an if-statement

If you add Var before the variable name, then its scoop is determined where its location is


Example:

var num1 = 18; // Global scope
function fun() {
  var num2 = 20; // Local (Function) Scope
  if (true) {
    var num3 = 22; // Block Scope (within an if-statement)
  }
}

num1 = 18; // Global scope
function fun() {
  num2 = 20; // Global Scope
  if (true) {
    num3 = 22; // Global Scope
  }
}

How can I see the size of a GitHub repository before cloning it?

One can achieve this using one's browser console and running

fetch('https://api.github.com/repos/[USERNAME]/[REPO]')
  .then(v => v.json()).then((function(v){
   console.log(v['size'] + "KB")
  })
)

Let's consider a practical example.

Assuming one wants to find the size of this repo using Firefox.

Open the console with Ctrl+Shift+K.

Then paste the following code

fetch('https://api.github.com/repos/goncaloperes/TimeSeries')
  .then(v => v.json()).then((function(v){
   console.log(v['size'] + "KB")
  })
)

Press enter and one will receive the size of the repo as one can see in the image bellow.

enter image description here

How do I sort strings alphabetically while accounting for value when a string is numeric?

namespace X
{
    public class Utils
    {
        public class StrCmpLogicalComparer : IComparer<Projects.Sample>
        {
            [DllImport("Shlwapi.dll", CharSet = CharSet.Unicode)]
            private static extern int StrCmpLogicalW(string x, string y);


            public int Compare(Projects.Sample x, Projects.Sample y)
            {
                string[] ls1 = x.sample_name.Split("_");
                string[] ls2 = y.sample_name.Split("_");
                string s1 = ls1[0];
                string s2 = ls2[0];
                return StrCmpLogicalW(s1, s2);
            }
        }

    }
}

Filter items which array contains any of given values

For those looking at this in 2020, you may notice that accepted answer is deprecated in 2020, but there is a similar approach available using terms_set and minimum_should_match_script combination.

Please see the detailed answer here in the SO thread

SimpleDateFormat parse loses timezone

tl;dr

what is the way to retrieve a Date object so that its always in GMT?

Instant.now() 

Details

You are using troublesome confusing old date-time classes that are now supplanted by the java.time classes.

Instant = UTC

The Instant class represents a moment on the timeline in UTC with a resolution of nanoseconds (up to nine (9) digits of a decimal fraction).

Instant instant = Instant.now() ; // Current moment in UTC.

ISO 8601

To exchange this data as text, use the standard ISO 8601 formats exclusively. These formats are sensibly designed to be unambiguous, easy to process by machine, and easy to read across many cultures by people.

The java.time classes use the standard formats by default when parsing and generating strings.

String output = instant.toString() ;  

2017-01-23T12:34:56.123456789Z

Time zone

If you want to see that same moment as presented in the wall-clock time of a particular region, apply a ZoneId to get a ZonedDateTime.

Specify a proper time zone name in the format of continent/region, such as America/Montreal, Africa/Casablanca, or Pacific/Auckland. Never use the 3-4 letter abbreviation such as EST or IST as they are not true time zones, not standardized, and not even unique(!).

ZoneId z = ZoneId.of( "Asia/Singapore" ) ;
ZonedDateTime zdt = instant.atZone( z ) ;  // Same simultaneous moment, same point on the timeline.

See this code live at IdeOne.com.

Notice the eight hour difference, as the time zone of Asia/Singapore currently has an offset-from-UTC of +08:00. Same moment, different wall-clock time.

instant.toString(): 2017-01-23T12:34:56.123456789Z

zdt.toString(): 2017-01-23T20:34:56.123456789+08:00[Asia/Singapore]

Convert

Avoid the legacy java.util.Date class. But if you must, you can convert. Look to new methods added to the old classes.

java.util.Date date = Date.from( instant ) ;

…going the other way…

Instant instant = myJavaUtilDate.toInstant() ;

Date-only

For date-only, use LocalDate.

LocalDate ld = zdt.toLocalDate() ;

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

How do I register a .NET DLL file in the GAC?

Try GACView if you have a fear of command prompts.

You have not set the PATH properly in DOS.You need to point the path to where the gacutil resides to use it in DOS.

How to change the status bar background color and text color on iOS 7?

The below code snippet should work with Objective C.

   if (@available(iOS 13.0, *)) {
      UIView *statusBar = [[UIView alloc]initWithFrame:[UIApplication sharedApplication].keyWindow.windowScene.statusBarManager.statusBarFrame] ;
      statusBar.backgroundColor = [UIColor whiteColor];
      [[UIApplication sharedApplication].keyWindow addSubview:statusBar];
  } else {
      // Fallback on earlier versions

       UIView *statusBar = [[[UIApplication sharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"];
          if ([statusBar respondsToSelector:@selector(setBackgroundColor:)]) {
              statusBar.backgroundColor = [UIColor whiteColor];//set whatever color you like
      }
  }

Count number of occurrences by month

Use a pivot table. You can manually refresh a pivot table's data source by right-clicking on it and clicking refresh. Otherwise you can set up a worksheet_change macro - or just a refresh button. Pivot Table tutorial is here: http://chandoo.org/wp/2009/08/19/excel-pivot-tables-tutorial/

1) Create a Month column from your Date column (e.g. =TEXT(B2,"MMM") )

image1

2) Create a Year column from your Date column (e.g. =TEXT(B2,"YYYY") )

image2

3) Add a Count column, with "1" for each value

image3

4) Create a Pivot table with the fields, Count, Month and Year 5) Drag the Year and Month fields into Row Labels. Ensure that Year is above month so your Pivot table first groups by year, then by month 6) Drag the Count field into Values to create a Count of Count

image4

There are better tutorials I'm sure just google/bing "pivot table tutorial".

How do I get the first n characters of a string without checking the size or going out of bounds?

There's a class of question on SO that sometimes make less than perfect sense, this one is perilously close :-)

Perhaps you could explain your aversion to using one of the two methods you ruled out.

If it's just because you don't want to pepper your code with if statements or exception catching code, one solution is to use a helper function that will take care of it for you, something like:

static String substring_safe (String s, int start, int len) { ... }

which will check lengths beforehand and act accordingly (either return smaller string or pad with spaces).

Then you don't have to worry about it in your code at all, just call:

String s2 = substring_safe (s, 10, 7);

instead of:

String s2 = s.substring (10,7);

This would work in the case that you seem to be worried about (based on your comments to other answers), not breaking the flow of the code when doing lots of string building stuff.

Databound drop down list - initial value

To select a value from the dropdown use the index like this:

if we have the

<asp:DropDownList ID="DropDownList1" runat="server" AppendDataBoundItems="true"></asp:DropDownList>

you would use :

DropDownList1.Items[DropDownList1.SelectedIndex].Value

this would return the value for the selected index.

Return multiple fields as a record in PostgreSQL with PL/pgSQL

If you have a table with this exact record layout, use its name as a type, otherwise you will have to declare the type explicitly:

CREATE OR REPLACE FUNCTION get_object_fields
        (
        name text
        )
RETURNS mytable
AS
$$
        DECLARE f1 INT;
        DECLARE f2 INT;
        …
        DECLARE f8 INT;
        DECLARE retval mytable;
        BEGIN
        -- fetch fields f1, f2 and f3 from table t1
        -- fetch fields f4, f5 from table t2
        -- fetch fields f6, f7 and f8 from table t3
                retval := (f1, f2, …, f8);
                RETURN retval;
        END
$$ language plpgsql; 

What is "Connect Timeout" in sql server connection string?

Connection Timeout=30 means that the database server has 30 seconds to establish a connection.

Connection Timeout specifies the time limit (in seconds), within which the connection to the specified server must be made, otherwise an exception is thrown i.e. It specifies how long you will allow your program to be held up while it establishes a database connection.

DataSource=server;
InitialCatalog=database;
UserId=username;
Password=password;
Connection Timeout=30

SqlConnection.ConnectionTimeout. specifies how many seconds the SQL Server service has to respond to a connection attempt. This is always set as part of the connection string.

Notes:

  • The value is expressed in seconds, not milliseconds.

  • The default value is 30 seconds.

  • A value of 0 means to wait indefinitely and never time out.

In addition, SqlCommand.CommandTimeout specifies the timeout value of a specific query running on SQL Server, however this is set via the SqlConnection object/setting (depending on your programming language), and not in the connection string i.e. It specifies how long you will allow your program to be held up while the command is run.

Writing numerical values on the plot with Matplotlib

Use pyplot.text() (import matplotlib.pyplot as plt)

import matplotlib.pyplot as plt

x=[1,2,3]
y=[9,8,7]

plt.plot(x,y)
for a,b in zip(x, y): 
    plt.text(a, b, str(b))
plt.show()

Can you "compile" PHP code and upload a binary-ish file, which will just be run by the byte code interpreter?

The short answer is "no".

The current implementation of PHP is that of an interpreted language. You can argue the theoretical aspects of the fact that any language can technically be interpreted or compiled, but as it stands, the current implementations are such that PHP code requires an interpreter to run, and the interpreter manages the executing environment.

To answer your question about uploading pre-compiled PHP bytecode, it's probably possible, but you'd have to implement a way for the PHP interpreter to read in such a file and work with it. With existing opcode caches out there already, it doesn't seem like a task that would reap much reward.

Set value of input instead of sendKeys() - Selenium WebDriver nodejs

JavascriptExecutor js = (JavascriptExecutor)driver;
js.executeScript("document.querySelector('attributeValue').value='new value'");

Best way to repeat a character in C#

Try this:

  1. Add Microsoft.VisualBasic reference
  2. Use: String result = Microsoft.VisualBasic.Strings.StrDup(5,"hi");
  3. Let me know if it works for you.

Passing arguments to JavaScript function from code-behind

include script manager

code behind function

ScriptManager.RegisterStartupScript(this, this.GetType(), "HideConfirmBox", "javascript:HideAAConfirmBox(); ", true);

After updating Entity Framework model, Visual Studio does not see changes

I also had this problem, however, right-clicking on the model.tt file and running "Custom tool" didn't make any difference for me somehow, but a comment on the page Ghlouw linked to mentioned to use the menu item "BUILD > Transform All T4 Templates." which did it for me

How to insert tab character when expandtab option is on in Vim

You can disable expandtab option from within Vim as below:

:set expandtab!

or

:set noet

PS: And set it back when you are done with inserting tab, with "set expandtab" or "set et"

PS: If you have tab set equivalent to 4 spaces in .vimrc (softtabstop), you may also like to set it to 8 spaces in order to be able to insert a tab by pressing tab key once instead of twice (set softtabstop=8).

How to execute UNION without sorting? (SQL)

select T.Col1, T.Col2, T.Sort
from 
    (
      select T.Col1,
             T.Col2,
             T.Sort,
             rank() over(partition by T.Col1, T.Col2 order by T.Sort) as rn
      from
          (
            select Col1, Col2, 1 as Sort
            from Table1
            union all
            select Col1, Col2, 2
            from Table2
          ) as T
    ) as T
where T.rn = 1    
order by T.Sort

How to create multidimensional array

Quote taken from Data Structures and Algorithms with JavaScript

The Good Parts (O’Reilly, p. 64). Crockford extends the JavaScript array object with a function that sets the number of rows and columns and sets each value to a value passed to the function. Here is his definition:

Array.matrix = function(numrows, numcols, initial) {
    var arr = [];
    for (var i = 0; i < numrows; ++i) {
        var columns = [];
        for (var j = 0; j < numcols; ++j) {
            columns[j] = initial;
        }
        arr[i] = columns;
    }
    return arr;
}

Here is some code to test the definition:

var nums = Array.matrix(5,5,0);
print(nums[1][1]); // displays 0
var names = Array.matrix(3,3,"");
names[1][2] = "Joe";
print(names[1][2]); // display "Joe"

We can also create a two-dimensional array and initialize it to a set of values in one line:

var grades = [[89, 77, 78],[76, 82, 81],[91, 94, 89]];
print(grades[2][2]); // displays 89

How do I create an Excel chart that pulls data from multiple sheets?

Use the Chart Wizard.

On Step 2 of 4, there is a tab labeled "Series". There are 3 fields and a list box on this tab. The list box shows the different series you are already including on the chart. Each series has both a "Name" field and a "Values" field that is specific to that series. The final field is the "Category (X) axis labels" field, which is common to all series.

Click on the "Add" button below the list box. This will add a blank series to your list box. Notice that the values for "Name" and for "Values" change when you highlight a series in the list box.

Select your new series.

There is an icon in each field on the right side. This icon allows you to select cells in the workbook to pull the data from. When you click it, the Wizard temporarily hides itself (except for the field you are working in) allowing you to interact with the workbook.

Select the appropriate sheet in the workbook and then select the fields with the data you want to show in the chart. The button on the right of the field can be clicked to unhide the wizard.

Hope that helps.

EDIT: The above applies to 2003 and before. For 2007, when the chart is selected, you should be able to do a similar action using the "Select Data" option on the "Design" tab of the ribbon. This opens up a dialog box listing the Series for the chart. You can select the series just as you could in Excel 2003, but you must use the "Add" and "Edit" buttons to define custom series.

How do I set proxy for chrome in python webdriver?

I had an issue with the same thing. ChromeOptions is very weird because it's not integrated with the desiredcapabilities like you would think. I forget the exact details, but basically ChromeOptions will reset to default certain values based on whether you did or did not pass a desired capabilities dict.

I did the following monkey-patch that allows me to specify my own dict without worrying about the complications of ChromeOptions

change the following code in /selenium/webdriver/chrome/webdriver.py:

def __init__(self, executable_path="chromedriver", port=0,
             chrome_options=None, service_args=None,
             desired_capabilities=None, service_log_path=None, skip_capabilities_update=False):
    """
    Creates a new instance of the chrome driver.

    Starts the service and then creates new instance of chrome driver.

    :Args:
     - executable_path - path to the executable. If the default is used it assumes the executable is in the $PATH
     - port - port you would like the service to run, if left as 0, a free port will be found.
     - desired_capabilities: Dictionary object with non-browser specific
       capabilities only, such as "proxy" or "loggingPref".
     - chrome_options: this takes an instance of ChromeOptions
    """
    if chrome_options is None:
        options = Options()
    else:
        options = chrome_options

    if skip_capabilities_update:
        pass
    elif desired_capabilities is not None:
        desired_capabilities.update(options.to_capabilities())
    else:
        desired_capabilities = options.to_capabilities()

    self.service = Service(executable_path, port=port,
        service_args=service_args, log_path=service_log_path)
    self.service.start()

    try:
        RemoteWebDriver.__init__(self,
            command_executor=self.service.service_url,
            desired_capabilities=desired_capabilities)
    except:
        self.quit()
        raise 
    self._is_remote = False

all that changed was the "skip_capabilities_update" kwarg. Now I just do this to set my own dict:

capabilities = dict( DesiredCapabilities.CHROME )

if not "chromeOptions" in capabilities:
    capabilities['chromeOptions'] = {
        'args' : [],
        'binary' : "",
        'extensions' : [],
        'prefs' : {}
    }

capabilities['proxy'] = {
    'httpProxy' : "%s:%i" %(proxy_address, proxy_port),
    'ftpProxy' : "%s:%i" %(proxy_address, proxy_port),
    'sslProxy' : "%s:%i" %(proxy_address, proxy_port),
    'noProxy' : None,
    'proxyType' : "MANUAL",
    'class' : "org.openqa.selenium.Proxy",
    'autodetect' : False
}

driver = webdriver.Chrome( executable_path="path_to_chrome", desired_capabilities=capabilities, skip_capabilities_update=True )

Convert Pandas Series to DateTime in a DataFrame

df=pd.read_csv("filename.csv" , parse_dates=["<column name>"])

type(df.<column name>)

example: if you want to convert day which is initially a string to a Timestamp in Pandas

df=pd.read_csv("weather_data2.csv" , parse_dates=["day"])

type(df.day)

The output will be pandas.tslib.Timestamp

How to make the tab character 4 spaces instead of 8 spaces in nano?

For future viewers, there is a line in my /etc/nanorc file close to line 153 that says "set tabsize 8". The word might need to be tabsize instead of tabspace. After I replaced 8 with 4 and uncommented the line, it solved my problem.

How to build a 2 Column (Fixed - Fluid) Layout with Twitter Bootstrap?

- Another Update -

Since Twitter Bootstrap version 2.0 - which saw the removal of the .container-fluid class - it has not been possible to implement a two column fixed-fluid layout using just the bootstrap classes - however I have updated my answer to include some small CSS changes that can be made in your own CSS code that will make this possible

It is possible to implement a fixed-fluid structure using the CSS found below and slightly modified HTML code taken from the Twitter Bootstrap Scaffolding : layouts documentation page:

HTML

<div class="container-fluid fill">
    <div class="row-fluid">
        <div class="fixed">  <!-- we want this div to be fixed width -->
            ...
        </div>
        <div class="hero-unit filler">  <!-- we have removed spanX class -->
            ...
        </div>
    </div>
</div>

CSS

/* CSS for fixed-fluid layout */

.fixed {
    width: 150px;  /* the fixed width required */
    float: left;
}

.fixed + div {
     margin-left: 150px;  /* must match the fixed width in the .fixed class */
     overflow: hidden;
}


/* CSS to ensure sidebar and content are same height (optional) */

html, body {
    height: 100%;
}

.fill { 
    min-height: 100%;
    position: relative;
}

.filler:after{
    background-color:inherit;
    bottom: 0;
    content: "";
    height: auto;
    min-height: 100%;
    left: 0;
    margin:inherit;
    right: 0;
    position: absolute;
    top: 0;
    width: inherit;
    z-index: -1;  
}

I have kept the answer below - even though the edit to support 2.0 made it a fluid-fluid solution - as it explains the concepts behind making the sidebar and content the same height (a significant part of the askers question as identified in the comments)


Important

Answer below is fluid-fluid

Update As pointed out by @JasonCapriotti in the comments, the original answer to this question (created for v1.0) did not work in Bootstrap 2.0. For this reason, I have updated the answer to support Bootstrap 2.0

To ensure that the main content fills at least 100% of the screen height, we need to set the height of the html and body to 100% and create a new css class called .fill which has a minimum-height of 100%:

html, body {
    height: 100%;
}

.fill { 
    min-height: 100%;
}

We can then add the .fill class to any element that we need to take up 100% of the sceen height. In this case we add it to the first div:

<div class="container-fluid fill">
    ...
</div>

To ensure that the Sidebar and the Content columns have the same height is very difficult and unnecessary. Instead we can use the ::after pseudo selector to add a filler element that will give the illusion that the two columns have the same height:

.filler::after {
    background-color: inherit;
    bottom: 0;
    content: "";
    right: 0;
    position: absolute;
    top: 0;
    width: inherit;
    z-index: -1;  
}

To make sure that the .filler element is positioned relatively to the .fill element we need to add position: relative to .fill:

.fill { 
    min-height: 100%;
    position: relative;
}

And finally add the .filler style to the HTML:

HTML

<div class="container-fluid fill">
    <div class="row-fluid">
        <div class="span3">
            ...
        </div>
        <div class="span9 hero-unit filler">
            ...
        </div>
    </div>
</div>

Notes

  • If you need the element on the left of the page to be the filler then you need to change right: 0 to left: 0.

How open PowerShell as administrator from the run window

Windows 10 appears to have a keyboard shortcut. According to How to open elevated command prompt in Windows 10 you can press ctrl + shift + enter from the search or start menu after typing cmd for the search term.

image of win 10 start menu
(source: winaero.com)

Nginx Different Domains on Same IP

Your "listen" directives are wrong. See this page: http://nginx.org/en/docs/http/server_names.html.

They should be

server {
    listen      80;
    server_name www.domain1.com;
    root /var/www/domain1;
}

server {
    listen       80;
    server_name www.domain2.com;
    root /var/www/domain2;
}

Note, I have only included the relevant lines. Everything else looked okay but I just deleted it for clarity. To test it you might want to try serving a text file from each server first before actually serving php. That's why I left the 'root' directive in there.

Changing datagridview cell color based on condition

Without looping it can be achived like below.

private void dgEvents_RowPrePaint(object sender, DataGridViewRowPrePaintEventArgs e)
    {

        FormatRow(dgEvents.Rows[e.RowIndex]);

    }

private void FormatRow(DataGridViewRow myrow)
    {
        try
        {
            if (Convert.ToString(myrow.Cells["LevelDisplayName"].Value) == "Error")
            {
                myrow.DefaultCellStyle.BackColor = Color.Red;
            }
            else if (Convert.ToString(myrow.Cells["LevelDisplayName"].Value) == "Warning")
            {
                myrow.DefaultCellStyle.BackColor = Color.Yellow;
            }
            else if (Convert.ToString(myrow.Cells["LevelDisplayName"].Value) == "Information")
            {
                myrow.DefaultCellStyle.BackColor = Color.LightGreen;
            }
        }
        catch (Exception exception)
        {
            onLogs?.Invoke(exception.Message, EventArgs.Empty);
        }
    }

How to handle login pop up window using Selenium WebDriver?

Now in 2020 Selenium 4 supports authenticating using Basic and Digest auth . Its using the CDP and currently only supports chromium-derived browsers

Example :

Java Example :

    Webdriver driver = new ChromeDriver();
    
    ((HasAuthentication) driver).register(UsernameAndPassword.of("username", "pass"));

    driver.get("http://sitewithauth");
    
 

Note : In Alpha-7 there is bug where it send username for both user/password. Need to wait for next release of selenium version as fix is available in trunk https://github.com/SeleniumHQ/selenium/commit/4917444886ba16a033a81a2a9676c9267c472894

How to safely call an async method in C# without await

If you want to get the exception "asynchronously", you could do:

  MyAsyncMethod().
    ContinueWith(t => Console.WriteLine(t.Exception),
        TaskContinuationOptions.OnlyOnFaulted);

This will allow you to deal with an exception on a thread other than the "main" thread. This means you don't have to "wait" for the call to MyAsyncMethod() from the thread that calls MyAsyncMethod; but, still allows you to do something with an exception--but only if an exception occurs.

Update:

technically, you could do something similar with await:

try
{
    await MyAsyncMethod().ConfigureAwait(false);
}
catch (Exception ex)
{
    Trace.WriteLine(ex);
}

...which would be useful if you needed to specifically use try/catch (or using) but I find the ContinueWith to be a little more explicit because you have to know what ConfigureAwait(false) means.

Parse JSON from JQuery.ajax success data

Well... you are about 3/4 of the way there... you already have your JSON as text.

The problem is that you appear to be handling this string as if it was already a JavaScript object with properties relating to the fields that were transmitted.

It isn't... its just a string.

Queries like "content = data[x].Id;" are bound to fail because JavaScript is not finding these properties attached to the string that it is looking at... again, its JUST a string.

You should be able to simply parse the data as JSON through... yup... the parse method of the JSON object.

myResult = JSON.parse(request.responseText);

Now myResult is a javascript object containing the properties that were transmitted through AJAX.

That should allow you to handle it the way you appear to be trying to.

Looks like JSON.parse was added when ECMA5 was added, so anything fairly modern should be able to handle this natively... if you have to handle fossils, you could also try external libraries to handle this, such as jQuery or JSON2.

For the record, this was already answered by Andy E for someone else HERE.

edit - Saw the request for 'official or credible sources', and probably one of the coders that I find the most credible would be John Resig ~ ECMA5 JSON ~ i would have linked to the actual ECMA5 spec regarding native JSON support, but I would rather refer someone to a master like Resig than a dry specification.

Get protocol + host name from URL

Here is a slightly improved version:

urls = [
    "http://stackoverflow.com:8080/some/folder?test=/questions/9626535/get-domain-name-from-url",
    "Stackoverflow.com:8080/some/folder?test=/questions/9626535/get-domain-name-from-url",
    "http://stackoverflow.com/some/folder?test=/questions/9626535/get-domain-name-from-url",
    "https://StackOverflow.com:8080?test=/questions/9626535/get-domain-name-from-url",
    "stackoverflow.com?test=questions&v=get-domain-name-from-url"]
for url in urls:
    spltAr = url.split("://");
    i = (0,1)[len(spltAr)>1];
    dm = spltAr[i].split("?")[0].split('/')[0].split(':')[0].lower();
    print dm

Output

stackoverflow.com
stackoverflow.com
stackoverflow.com
stackoverflow.com
stackoverflow.com

Fiddle: https://pyfiddle.io/fiddle/23e4976e-88d2-4757-993e-532aa41b7bf0/?i=true

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

The trick is that you need to create an environment/workspace for Python. This solution should work for Python 2.7 but at the time of writing keras can run on python 3.5, especially if you have the latest anaconda installed (this took me awhile to figure out so I'll outline the steps I took to install KERAS in python 3.5):

Create environment/workspace for Python 3.5

  1. C:\conda create --name neuralnets python=3.5
  2. C:\activate neuralnets

Install everything (notice the neuralnets workspace in parenthesis on each line). Accept any dependencies each of those steps wants to install:

  1. (neuralnets) C:\conda install theano
  2. (neuralnets) C:\conda install mingw libpython
  3. (neuralnets) C:\pip install tensorflow
  4. (neuralnets) C:\pip install keras

Test it out:

(neuralnets) C:\python -c "from keras import backend; print(backend._BACKEND)"

Just remember, if you want to work in the workspace you always have to do:

C:\activate neuralnets

so you can launch Jupyter for example (assuming you also have Jupyter installed in this environment/workspace) as:

C:\activate neuralnets
(neuralnets) jupyter notebook

You can read more about managing and creating conda environments/workspaces at the follwing URL: https://conda.io/docs/using/envs.html

CodeIgniter PHP Model Access "Unable to locate the model you have specified"

If you are on Linux then make sure your File name must match with the string passed in the load model methods the first argument.

$this->load->model('Order_Model','order_model');

You can use the second argument using that you can call methods from your model and it will work on Linux and windows as well

$result = $this->order_model->get_order_details($orderID);

How to parse JSON using Node.js?

Use JSON.parse(str);. Read more about it here.

Here are some examples:

var jsonStr = '{"result":true, "count":42}';

obj = JSON.parse(jsonStr);

console.log(obj.count);    // expected output: 42
console.log(obj.result);   // expected output: true

Find all files in a folder

A lot of these answers won't actually work, having tried them myself. Give this a go:

string filepath = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
DirectoryInfo d = new DirectoryInfo(filepath);

foreach (var file in d.GetFiles("*.txt"))
{
      Directory.Move(file.FullName, filepath + "\\TextFiles\\" + file.Name);
}

It will move all .txt files on the desktop to the folder TextFiles.

Android Percentage Layout Height

android:layout_weight=".YOURVALUE" is best way to implement in percentage

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/logTextBox"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight=".20"
        android:maxLines="500"
        android:scrollbars="vertical"
        android:singleLine="false"
        android:text="@string/logText" >
    </TextView>

</LinearLayout>

undefined offset PHP error

If preg_match did not find a match, $matches is an empty array. So you should check if preg_match found an match before accessing $matches[0], for example:

function get_match($regex,$content)
{
    if (preg_match($regex,$content,$matches)) {
        return $matches[0];
    } else {
        return null;
    }
}

How do I make my ArrayList Thread-Safe? Another approach to problem in Java?

You might be using the wrong approach. Just because one thread that simulates a car finishes before another car-simulation thread doesn't mean that the first thread should win the simulated race.

It depends a lot on your application, but it might be better to have one thread that computes the state of all cars at small time intervals until the race is complete. Or, if you prefer to use multiple threads, you might have each car record the "simulated" time it took to complete the race, and choose the winner as the one with shortest time.

How do I increment a DOS variable in a FOR /F loop?

The problem with your code snippet is the way variables are expanded. Variable expansion is usually done when a statement is first read. In your case the whole FOR loop and its block is read and all variables, except the loop variables are expanded to their current value.

This means %c% in your echo %%i, %c% expanded instantly and so is actually used as echo %%i, 1 in each loop iteration.

So what you need is the delayed variable expansion. Find some good explanation about it here.

Variables that should be delay expanded are referenced with !VARIABLE! instead of %VARIABLE%. But you need to activate this feature with setlocal ENABLEDELAYEDEXPANSION and reset it with a matching endlocal.

Your modified code would look something like that:

set TEXT_T="myfile.txt"

set /a c=1

setlocal ENABLEDELAYEDEXPANSION

FOR /F "tokens=1 usebackq" %%i in (%TEXT_T%) do (
  set /a c=c+1

  echo %%i, !c!
)

endlocal

Difference between xcopy and robocopy

Its painful to hear people are still suffering at the hands of *{COPY} whatever the version. I am a seasoned batch and Bash script writer and I recommend rsync , you can run this within cygwin (cygwin.org) or you can locate some binaries floating around . and you can redirect output to 2>&1 to some log file like out.log for later analysing. Good luck people its time to love life again . =M. Kaan=

Curl: Fix CURL (51) SSL error: no alternative certificate subject name matches

I had the same issue. In my case I was using digitalocean and nginx.
I have first setup a domain example.app and a subdomain dev.exemple.app in digitalocean. Second,I purchased two ssl certificat from godaddy. And finaly, I configured two domain in nginx to use those two ssl certificat with the following snipet

My example.app domain config

    server {
    listen 7000 default_server;
    listen [::]:7000 default_server;

     listen 443 ssl default_server;
     listen [::]:443 ssl default_server;

    root /srv/nodejs/echantillonnage1;

    # Add index.php to the list if you are using PHP
    index index.html index.htm index.nginx-debian.html;

    server_name echantillonnage.app;
    ssl_certificate /srv/nodejs/certificatSsl/widcardcertificate/echantillonnage.app.chained.crt;
    ssl_certificate_key /srv/nodejs/certificatSsl/widcardcertificate/echantillonnage.app.key;

    location / {
            # First attempt to serve request as file, then
            # as directory, then fall back to displaying a 404.
            proxy_pass http://127.0.0.1:8090;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection 'upgrade';
            proxy_set_header Host $host;
            proxy_cache_bypass $http_upgrade;
    #try_files $uri $uri/ =404;
    }
 }

My dev.example.app

   server {
    listen 7000 default_server;
    listen [::]:7000 default_server;

     listen 444 ssl default_server;
     listen [::]:444 ssl default_server;

    root /srv/nodejs/echantillonnage1;

    # Add index.php to the list if you are using PHP
    index index.html index.htm index.nginx-debian.html;

    server_name dev.echantillonnage.app;
    ssl_certificate /srv/nodejs/certificatSsl/dev/dev.echantillonnage.app.chained.crt;
    ssl_certificate_key /srv/nodejs/certificatSsl/dev/dev.echantillonnage.app.key;

    location / {
            # First attempt to serve request as file, then
            # as directory, then fall back to displaying a 404.
            proxy_pass http://127.0.0.1:8091;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection 'upgrade';
            proxy_set_header Host $host;
            proxy_cache_bypass $http_upgrade;
    #try_files $uri $uri/ =404;
    }
 }

When I was launching https://dev.echantillonnage.app , I was getting

    Fix CURL (51) SSL error: no alternative certificate subject name matches

My mistake was the two lines bellow

    listen 444 ssl default_server;
     listen [::]:444 ssl default_server;

I had to change this to:

     listen 443 ssl;
     listen [::]:443 ssl;

How do I remove a single breakpoint with GDB?

You can delete all breakpoints using

del <start_breakpoint_num> - <end_breakpoint_num>

To view the start_breakpoint_num and end_breakpoint_num use:

info break

How can I scroll to a specific location on the page using jquery?

Here is variant of @juraj-blahunka's lightweight approach. This function does not assume the container is the document and only scrolls if the item is out of view. Animation queuing is also disabled to avoid unnecessary bouncing.

$.fn.scrollToView = function () {
    return $.each(this, function () {
        if ($(this).position().top < 0 ||
            $(this).position().top + $(this).height() > $(this).parent().height()) {
            $(this).parent().animate({
                scrollTop: $(this).parent().scrollTop() + $(this).position().top
            }, {
                duration: 300,
                queue: false
            });
        }
    });
};

Relative Paths in Javascript in an external file

Please use the following syntax to enjoy the luxury of asp.net tilda ("~") in javascript

<script src=<%=Page.ResolveUrl("~/MasterPages/assets/js/jquery.js")%>></script>

making a paragraph in html contain a text from a file

You can do something like that in pure html using an <object> tag:
<div><object data="file.txt"></object></div>

This method has some limitations though, like, it won't fit size of the block to the content - you have to specify width and height manually. And styles won't be applied to the text.

C# 4.0 optional out/ref arguments

There actually is a way to do this that is allowed by C#. This gets back to C++, and rather violates the nice Object-Oriented structure of C#.

USE THIS METHOD WITH CAUTION!

Here's the way you declare and write your function with an optional parameter:

unsafe public void OptionalOutParameter(int* pOutParam = null)
{
    int lInteger = 5;
    // If the parameter is NULL, the caller doesn't care about this value.
    if (pOutParam != null) 
    { 
        // If it isn't null, the caller has provided the address of an integer.
        *pOutParam = lInteger; // Dereference the pointer and assign the return value.
    }
}

Then call the function like this:

unsafe { OptionalOutParameter(); } // does nothing
int MyInteger = 0;
unsafe { OptionalOutParameter(&MyInteger); } // pass in the address of MyInteger.

In order to get this to compile, you will need to enable unsafe code in the project options. This is a really hacky solution that usually shouldn't be used, but if you for some strange, arcane, mysterious, management-inspired decision, REALLY need an optional out parameter in C#, then this will allow you to do just that.

How to add Options Menu to Fragment in Android

Set setHasMenuOptions(true) works if application has a theme with Actionbar such as Theme.MaterialComponents.DayNight.DarkActionBar or Activity has it's own Toolbar, otherwise onCreateOptionsMenu in fragment does not get called.

If you want to use standalone Toolbar you either need to get activity and set your Toolbar as support action bar with

(requireActivity() as? MainActivity)?.setSupportActionBar(toolbar)

which lets your fragment onCreateOptionsMenu to be called.

Other alternative is, you can inflate your Toolbar's own menu with toolbar.inflateMenu(R.menu.YOUR_MENU) and item listener with

toolbar.setOnMenuItemClickListener {
   // do something
   true
}

Adding simple legend to plot in R

Take a look at ?legend and try this:

legend('topright', names(a)[-1] , 
   lty=1, col=c('red', 'blue', 'green',' brown'), bty='n', cex=.75)

enter image description here

Laravel Eloquent ORM Transactions

You can do this:

DB::transaction(function() {
      //
});

Everything inside the Closure executes within a transaction. If an exception occurs it will rollback automatically.