Programs & Examples On #Sfauthorizationpluginview

Call javascript from MVC controller action

<script>
    $(document).ready(function () {
        var msg = '@ViewBag.ErrorMessage'
        if (msg.length > 0)
            OnFailure('Register', msg);
    });

    function OnSuccess(header,Message) {
        $("#Message_Header").text(header);
        $("#Message_Text").text(Message);
        $('#MessageDialog').modal('show');
    }

    function OnFailure(header,error)
    {
        $("#Message_Header").text(header);
        $("#Message_Text").text(error);
        $('#MessageDialog').modal('show');
    }
</script>

window.location.href not working

The browser is still submitting the form after your code runs.

Add return false; to the handler to prevent that.

https connection using CURL from command line

you could use this

curl_setopt($curl->curl, CURLOPT_SSL_VERIFYPEER, false);

Force uninstall of Visual Studio

I was running in to the same issue, but have just managed a full uninstall by means of trusty old CMD:

D:\vs_ultimate.exe /uninstall /force

Where D: is the location of your installation media (mounted iso, etc).

You could also pass /passive (no user input required - just progress displayed) or /quiet to the above command line.

EDIT: Adding link below to MSDN article mentioning that this forcibly removes ALL installed components.

http://blogs.msdn.com/b/heaths/archive/2015/07/17/removing-visual-studio-components-left-behind-after-an-uninstall.aspx

Also, to ensure link rot doesn't invalidate this, adding brief text below from original article.

Starting with Visual Studio 2013, you can forcibly remove almost all components. A few core components – like the .NET Framework and VC runtimes – are left behind because of their ubiquity, though you can remove those separately from Programs and Features if you really want.

Warning: This will remove all components regardless of whether other products require them. This may cause other products to function incorrectly or not function at all.

Good luck!

How to check if a process id (PID) exists

ps command with -p $PID can do this:

$ ps -p 3531
  PID TTY          TIME CMD
 3531 ?        00:03:07 emacs

Google Chrome form autofill and its yellow background

A combination of answers worked for me

<style>
    input:-webkit-autofill,
    input:-webkit-autofill:hover,
    input:-webkit-autofill:focus,
    input:-webkit-autofill:active {
        -webkit-box-shadow: 0 0 0px 1000px #373e4a inset !important;
           -webkit-text-fill-color: white !important;
   }
</style>

What dependency is missing for org.springframework.web.bind.annotation.RequestMapping?

I don't think the problem is the dependencies. I guess you are getting that error on your IDE. Then just refresh it. If it's eclipse, try running Maven->Update Dependencies

VBA setting the formula for a cell

Not sure what isn't working in your case, but the following code will put a formula into cell A1 that will retrieve the value in the cell G2.

strProjectName = "Sheet1"
Cells(1, 1).Formula = "=" & strProjectName & "!" & Cells(2, 7).Address

The workbook and worksheet that strProjectName references must exist at the time that this formula is placed. Excel will immediately try to evaluate the formula. You might be able to stop that from happening by turning off automatic recalculation until the workbook does exist.

reading external sql script in python

according me, it is not possible

solution:

  1. import .sql file on mysql server

  2. after

    import mysql.connector
    import pandas as pd
    

    and then you use .sql file by convert to dataframe

How to call loading function with React useEffect only once

I like to define a mount function, it tricks EsLint in the same way useMount does and I find it more self-explanatory.

const mount = () => {
  console.log('mounted')
  // ...

  const unmount = () => {
    console.log('unmounted')
    // ...
  }
  return unmount
}
useEffect(mount, [])

Open local folder from link

add on click open local directory o local file to google chrome:

The solution from JFish222 works ( URL file solution )

For Webkid Browsers like Chrome on Apache Servers just add to .htaccess o http.config this code:

SetEnvIf Request_URI ".url$" requested_url=url Header add Content-Disposition "attachment" env=requested_url

And by the first downlod of your url file click on the file in chromes downloadbar and select "always open this file".

Increase max_execution_time in PHP?

Add this to an htaccess file (and see edit notes added below):

<IfModule mod_php5.c>
   php_value post_max_size 200M
   php_value upload_max_filesize 200M
   php_value memory_limit 300M
   php_value max_execution_time 259200
   php_value max_input_time 259200
   php_value session.gc_maxlifetime 1200
</IfModule>

Additional resources and information:


2021 EDIT:

As PHP and Apache evolve and grow, I think it is important for me to take a moment to mention a few things to consider and possible "gotchas" to consider:

  • PHP can be run as a module or as CGI. It is not recommended to run as CGI as it creates a lot of opportunities for attack vectors [Read More]. Running as a module (the safer option) will trigger the settings to be used if the specific module from <IfModule is loaded.
  • The answer indicates to write mod_php5.c in the first line. If you are using PHP 7, you would replace that with mod_php7.c.
  • Sometimes after you make changes to your .htaccess file, restarting Apache or NGINX will not work. The most common reason for this is you are running PHP-FPM, which runs as a separate process. You need to restart that as well.
  • Remember these are settings that are normally defined in your php.ini config file(s). This method is usually only useful in the event your hosting provider does not give you access to change those files. In circumstances where you can edit the PHP configuration, it is recommended that you apply these settings there.
  • Finally, it's important to note that not all php.ini settings can be configured via an .htaccess file. A file list of php.ini directives can be found here, and the only ones you can change are the ones in the changeable column with the modes PHP_INI_ALL or PHP_INI_PERDIR.

How to connect to remote Oracle DB with PL/SQL Developer?

The problem is not the TNS file, in PLSQL Developer, if you don't have the oracle installation, you need to provide the location of the OCI.DLL file.

In PLSQL DEV app go to Tools-Preferences-Oracle/connections-OCI Library.

In my case I put the next address C:\Oracle\InstantClient-win32-11.2.0.1.0\oci.dll.

If have Weblogic app installed, I didnt tried but if you want try to put the next location

C:\Oracle\Middleware\wlserver_10.3\server\adr.

Angular File Upload

First, you need to set up HttpClient in your Angular project.

Open the src/app/app.module.ts file, import HttpClientModule and add it to the imports array of the module as follows:

import { BrowserModule } from '@angular/platform-browser';  
import { NgModule } from '@angular/core';
import { AppRoutingModule } from './app-routing.module';  
import { AppComponent } from './app.component';  
import { HttpClientModule } from '@angular/common/http';

@NgModule({  
  declarations: [  
    AppComponent,  
  ],  
  imports: [  
    BrowserModule,  
    AppRoutingModule,  
    HttpClientModule  
  ],  
  providers: [],  
  bootstrap: [AppComponent]  
})  
export class AppModule { }

Next, generate a component:

$ ng generate component home

Next, generate an upload service:

$ ng generate service upload

Next, open the src/app/upload.service.ts file as follows:

import { HttpClient, HttpEvent, HttpErrorResponse, HttpEventType } from  '@angular/common/http';  
import { map } from  'rxjs/operators';

@Injectable({  
  providedIn: 'root'  
})  
export class UploadService { 
    SERVER_URL: string = "https://file.io/";  
    constructor(private httpClient: HttpClient) { }
    public upload(formData) {

      return this.httpClient.post<any>(this.SERVER_URL, formData, {  
         reportProgress: true,  
         observe: 'events'  
      });  
   }
}

Next, open the src/app/home/home.component.ts file, and start by adding the following imports:

import { Component, OnInit, ViewChild, ElementRef  } from '@angular/core';
import { HttpEventType, HttpErrorResponse } from '@angular/common/http';
import { of } from 'rxjs';  
import { catchError, map } from 'rxjs/operators';  
import { UploadService } from  '../upload.service';

Next, define the fileUpload and files variables and inject UploadService as follows:

@Component({  
  selector: 'app-home',  
  templateUrl: './home.component.html',  
  styleUrls: ['./home.component.css']  
})  
export class HomeComponent implements OnInit {
    @ViewChild("fileUpload", {static: false}) fileUpload: ElementRef;files  = [];  
    constructor(private uploadService: UploadService) { }

Next, define the uploadFile() method:

uploadFile(file) {  
    const formData = new FormData();  
    formData.append('file', file.data);  
    file.inProgress = true;  
    this.uploadService.upload(formData).pipe(  
      map(event => {  
        switch (event.type) {  
          case HttpEventType.UploadProgress:  
            file.progress = Math.round(event.loaded * 100 / event.total);  
            break;  
          case HttpEventType.Response:  
            return event;  
        }  
      }),  
      catchError((error: HttpErrorResponse) => {  
        file.inProgress = false;  
        return of(`${file.data.name} upload failed.`);  
      })).subscribe((event: any) => {  
        if (typeof (event) === 'object') {  
          console.log(event.body);  
        }  
      });  
  }

Next, define the uploadFiles() method which can be used to upload multiple image files:

private uploadFiles() {  
    this.fileUpload.nativeElement.value = '';  
    this.files.forEach(file => {  
      this.uploadFile(file);  
    });  
}

Next, define the onClick() method:

onClick() {  
    const fileUpload = this.fileUpload.nativeElement;fileUpload.onchange = () => {  
    for (let index = 0; index < fileUpload.files.length; index++)  
    {  
     const file = fileUpload.files[index];  
     this.files.push({ data: file, inProgress: false, progress: 0});  
    }  
      this.uploadFiles();  
    };  
    fileUpload.click();  
}

Next, we need to create the HTML template of our image upload UI. Open the src/app/home/home.component.html file and add the following content:

<div [ngStyle]="{'text-align':center; 'margin-top': 100px;}">
   <button mat-button color="primary" (click)="fileUpload.click()">choose file</button>  
   <button mat-button color="warn" (click)="onClick()">Upload</button>  
   <input [hidden]="true" type="file" #fileUpload id="fileUpload" name="fileUpload" multiple="multiple" accept="image/*" />
</div>

Check out this tutorial and this post

jQuery serialize does not register checkboxes

This example assumes you want to post a form back via serialize and not serializeArray, and that an unchecked checkbox means false:

var form = $(formSelector);
var postData = form.serialize();

var checkBoxData = form.find('input[type=checkbox]:not(:checked)').map(function () {
    return encodeURIComponent(this.name) + '=' + false;
}).get().join('&');

if (checkBoxData) {
    postData += "&" + checkBoxData;
}

$.post(action, postData);

SQL LIKE condition to check for integer?

PostgreSQL supports regular expressions matching.

So, your example would look like

SELECT * FROM books WHERE title ~ '^\d+ ?' 

This will match a title starting with one or more digits and an optional space

How to convert a Hibernate proxy to a real entity object

I've written following code which cleans object from proxies (if they are not already initialized)

public class PersistenceUtils {

    private static void cleanFromProxies(Object value, List<Object> handledObjects) {
        if ((value != null) && (!isProxy(value)) && !containsTotallyEqual(handledObjects, value)) {
            handledObjects.add(value);
            if (value instanceof Iterable) {
                for (Object item : (Iterable<?>) value) {
                    cleanFromProxies(item, handledObjects);
                }
            } else if (value.getClass().isArray()) {
                for (Object item : (Object[]) value) {
                    cleanFromProxies(item, handledObjects);
                }
            }
            BeanInfo beanInfo = null;
            try {
                beanInfo = Introspector.getBeanInfo(value.getClass());
            } catch (IntrospectionException e) {
                // LOGGER.warn(e.getMessage(), e);
            }
            if (beanInfo != null) {
                for (PropertyDescriptor property : beanInfo.getPropertyDescriptors()) {
                    try {
                        if ((property.getWriteMethod() != null) && (property.getReadMethod() != null)) {
                            Object fieldValue = property.getReadMethod().invoke(value);
                            if (isProxy(fieldValue)) {
                                fieldValue = unproxyObject(fieldValue);
                                property.getWriteMethod().invoke(value, fieldValue);
                            }
                            cleanFromProxies(fieldValue, handledObjects);
                        }
                    } catch (Exception e) {
                        // LOGGER.warn(e.getMessage(), e);
                    }
                }
            }
        }
    }

    public static <T> T cleanFromProxies(T value) {
        T result = unproxyObject(value);
        cleanFromProxies(result, new ArrayList<Object>());
        return result;
    }

    private static boolean containsTotallyEqual(Collection<?> collection, Object value) {
        if (CollectionUtils.isEmpty(collection)) {
            return false;
        }
        for (Object object : collection) {
            if (object == value) {
                return true;
            }
        }
        return false;
    }

    public static boolean isProxy(Object value) {
        if (value == null) {
            return false;
        }
        if ((value instanceof HibernateProxy) || (value instanceof PersistentCollection)) {
            return true;
        }
        return false;
    }

    private static Object unproxyHibernateProxy(HibernateProxy hibernateProxy) {
        Object result = hibernateProxy.writeReplace();
        if (!(result instanceof SerializableProxy)) {
            return result;
        }
        return null;
    }

    @SuppressWarnings("unchecked")
    private static <T> T unproxyObject(T object) {
        if (isProxy(object)) {
            if (object instanceof PersistentCollection) {
                PersistentCollection persistentCollection = (PersistentCollection) object;
                return (T) unproxyPersistentCollection(persistentCollection);
            } else if (object instanceof HibernateProxy) {
                HibernateProxy hibernateProxy = (HibernateProxy) object;
                return (T) unproxyHibernateProxy(hibernateProxy);
            } else {
                return null;
            }
        }
        return object;
    }

    private static Object unproxyPersistentCollection(PersistentCollection persistentCollection) {
        if (persistentCollection instanceof PersistentSet) {
            return unproxyPersistentSet((Map<?, ?>) persistentCollection.getStoredSnapshot());
        }
        return persistentCollection.getStoredSnapshot();
    }

    private static <T> Set<T> unproxyPersistentSet(Map<T, ?> persistenceSet) {
        return new LinkedHashSet<T>(persistenceSet.keySet());
    }

}

I use this function over result of my RPC services (via aspects) and it cleans recursively all result objects from proxies (if they are not initialized).

Android WebView not loading URL

Use the following things on your webview

webview.setWebChromeClient(new WebChromeClient());

then implement the required methods for WebChromeClient class.

Disable Auto Zoom in Input "Text" tag - Safari on iPhone

Inspired by @jirikuchta 's answer, I solved this problem by adding this bit of CSS:

#myTextArea:active {
  font-size: 16px; /* `16px` is safer I assume, although `1rem` works too */
}

No JS, and I don't notice any flash or anything.

It's worth noting that a viewport with maximum-scale=1 also works, but not when the page is loaded as an iframe, or if you have some other script modifying the viewport, etc.

MySQL - Operand should contain 1 column(s)

This error can also occur if you accidentally miss if function name.

for example:

set v_filter_value = 100;

select
    f_id,
    f_sale_value
from
    t_seller
where
    f_id = 5
    and (v_filter_value <> 0, f_sale_value = v_filter_value, true);

Got this problem when I missed putting if in the if function!

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

Get month and year from date cells Excel

I had a requirement to provide a report showing details by month where the date field was formatted as date & time, I simply changed the formatting of the date column to "General" and then used the following formula in a new column,

=CONCATENATE(YEAR(C2),MONTH(C2)) 

List of foreign keys and the tables they reference in Oracle DB

Try this:

select * from all_constraints where r_constraint_name in (select constraint_name 
from all_constraints where table_name='YOUR_TABLE_NAME');

How do you style a TextInput in react native for password input

A little plus:

version = RN 0.57.7

secureTextEntry={true}

does not work when the keyboardType was "phone-pad" or "email-address"

How to get just the date part of getdate()?

try this:

select convert (date ,getdate())

or

select CAST (getdate() as DATE)

or

select convert(varchar(10), getdate(),121)

How does ifstream's eof() work?

eof() checks the eofbit in the stream state.

On each read operation, if the position is at the end of stream and more data has to be read, eofbit is set to true. Therefore you're going to get an extra character before you get eofbit=1.

The correct way is to check whether the eof was reached (or, whether the read operation succeeded) after the reading operation. This is what your second version does - you do a read operation, and then use the resulting stream object reference (which >> returns) as a boolean value, which results in check for fail().

How to properly express JPQL "join fetch" with "where" clause as JPA 2 CriteriaQuery?

I will show visually the problem, using the great example from James answer and adding the alternative solution.

When you do the follow query, without the FETCH:

Select e from Employee e 
join e.phones p 
where p.areaCode = '613'

You will have the follow results from Employee as you expected:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613
1 James 6 416

But when you add the FETCH word on JOIN, this is what happens:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613

The generated SQL is the same for the two queries, but the Hibernate removes on memory the 416 register when you use WHERE on the FETCH join.

So, to bring all phones and apply the WHERE correctly, you need to have two JOINs: one for the WHERE and another for the FETCH. Like:

Select e from Employee e 
join e.phones p 
join fetch e.phones      //no alias, to not commit the mistake
where p.areaCode = '613'

Creating a search form in PHP to search a database?

You're getting errors 'table liam does not exist' because the table's name is Liam which is not the same as liam. MySQL table names are case sensitive.

How to read keyboard-input?

try

raw_input('Enter your input:')  # If you use Python 2
input('Enter your input:')      # If you use Python 3

and if you want to have a numeric value just convert it:

try:
    mode=int(raw_input('Input:'))
except ValueError:
    print "Not a number"

javac error: Class names are only accepted if annotation processing is explicitly requested

chandan@cmaster:~/More$ javac New.java
chandan@cmaster:~/More$ javac New
error: Class names, 'New', are only accepted if annotation processing is explicitly requested
1 error

So if you by mistake after compiling again use javac for running a program.

SQL Insert into table only if record doesn't exist

Assuming you cannot modify DDL (to create a unique constraint) or are limited to only being able to write DML then check for a null on filtered result of your values against the whole table

FIDDLE

insert into funds (ID, date, price) 
select 
    T.* 
from 
    (select 23 ID,  '2013-02-12' date,  22.43 price) T  
        left join 
    funds on funds.ID = T.ID and funds.date = T.date
where 
    funds.ID is null

Visual Studio 2015 or 2017 does not discover unit tests

Go to Nuget package manager and download Nunit Adapter as follow.

enter image description here

Suppress console output in PowerShell

Try redirecting the output to Out-Null. Like so,

$key = & 'gpg' --decrypt "secret.gpg" --quiet --no-verbose | out-null

rejected master -> master (non-fast-forward)

I had this problem on a development machine. The dev branch was pushing fine but the the master branch gave me (while git pushing when being on the dev branch):

! [rejected]        master -> master (non-fast-forward)

So I tried:

git checkout master
git pull

Which gave me:

You asked me to pull without telling me which branch you
want to merge with, and 'branch.master.merge' in
your configuration file does not tell me, either.

I found out the master branch was missing from .git/config and added:

[branch "master"]
    remote = origin
    merge = refs/heads/master

Afterwards git push also worked fine on the dev branch.

Using import fs from 'fs'

In order to use import { readFileSync } from 'fs', you have to:

  1. Be using Node.js 10 or later
  2. Use the --experimental-modules flag (in Node.js 10), e.g. node --experimental-modules server.mjs (see #3 for explanation of .mjs)
  3. Rename the file extension of your file with the import statements, to .mjs, .js will not work, e.g. server.mjs

The other answers hit on 1 and 2, but 3 is also necessary. Also, note that this feature is considered extremely experimental at this point (1/10 stability) and not recommended for production, but I will still probably use it.

Here's the Node.js 10 ESM documentation.

What is the best way to get all the divisors of a number?

Here is a smart and fast way to do it for numbers up to and around 10**16 in pure Python 3.6,

from itertools import compress

def primes(n):
    """ Returns  a list of primes < n for n > 2 """
    sieve = bytearray([True]) * (n//2)
    for i in range(3,int(n**0.5)+1,2):
        if sieve[i//2]:
            sieve[i*i//2::i] = bytearray((n-i*i-1)//(2*i)+1)
    return [2,*compress(range(3,n,2), sieve[1:])]

def factorization(n):
    """ Returns a list of the prime factorization of n """
    pf = []
    for p in primeslist:
      if p*p > n : break
      count = 0
      while not n % p:
        n //= p
        count += 1
      if count > 0: pf.append((p, count))
    if n > 1: pf.append((n, 1))
    return pf

def divisors(n):
    """ Returns an unsorted list of the divisors of n """
    divs = [1]
    for p, e in factorization(n):
        divs += [x*p**k for k in range(1,e+1) for x in divs]
    return divs

n = 600851475143
primeslist = primes(int(n**0.5)+1) 
print(divisors(n))

How do I implement Toastr JS?

Toastr is a very nice component, and you can show messages with theses commands:

// for success - green box
toastr.success('Success messages');

// for errors - red box
toastr.error('errors messages');

// for warning - orange box
toastr.warning('warning messages');

// for info - blue box
toastr.info('info messages');

If you want to provide a title on the toastr message, just add a second argument:

// for info - blue box
toastr.success('The process has been saved.', 'Success');

you also can change the default behaviour using something like this:

toastr.options.timeOut = 3000; // 3s

See more on the github of the project.

Edits

A sample of use:

$(document).ready(function() {

    // show when page load
    toastr.info('Page Loaded!');

    $('#linkButton').click(function() {
       // show when the button is clicked
       toastr.success('Click Button');

    });

});

and a html:

<a id='linkButton'>Show Message</a>

How to redirect stdout to both file and console with scripting?

I've tried a few solutions here and didn't find the one that writes into file and into console at the same time. So here is what I did (based on this answer)

class Logger(object):
    def __init__(self):
        self.terminal = sys.stdout

    def write(self, message):
        with open ("logfile.log", "a", encoding = 'utf-8') as self.log:            
            self.log.write(message)
        self.terminal.write(message)

    def flush(self):
        #this flush method is needed for python 3 compatibility.
        #this handles the flush command by doing nothing.
        #you might want to specify some extra behavior here.
        pass
sys.stdout = Logger()   

This solution uses more computing power, but reliably saves all of the data from stdout into logger file and uses less memeory. For my needs I've added time stamp into self.log.write(message) aswell. Works great.

Where is HttpContent.ReadAsAsync?

It looks like it is an extension method (in System.Net.Http.Formatting):

HttpContentExtensions Class

Update:

PM> install-package Microsoft.AspNet.WebApi.Client

According to the System.Net.Http.Formatting NuGet package page, the System.Net.Http.Formatting package is now legacy and can instead be found in the Microsoft.AspNet.WebApi.Client package available on NuGet here.

When should I use double or single quotes in JavaScript?

Single Quotes

I wish double quotes were the standard, because they make a little bit more sense, but I keep using single quotes because they dominate the scene.

Single quotes:

No preference:

Double quotes:

Testing Private method using mockito

There is actually a way to test methods from a private member with Mockito. Let's say you have a class like this:

public class A {
    private SomeOtherClass someOtherClass;
    A() {
        someOtherClass = new SomeOtherClass();
    }
    public void method(boolean b){
        if (b == true)
            someOtherClass.method1();
        else
            someOtherClass.method2();
    }

}

public class SomeOtherClass {
    public void method1() {}
    public void method2() {}
}

If you want to test a.method will invoke a method from SomeOtherClass, you can write something like below.

@Test
public void testPrivateMemberMethodCalled() {
    A a = new A();
    SomeOtherClass someOtherClass = Mockito.spy(new SomeOtherClass());
    ReflectionTestUtils.setField( a, "someOtherClass", someOtherClass);
    a.method( true );

    Mockito.verify( someOtherClass, Mockito.times( 1 ) ).method1();
}

ReflectionTestUtils.setField(); will stub the private member with something you can spy on.

How to check if bootstrap modal is open, so I can use jquery validate?

You can use

$('#myModal').hasClass('in');

Bootstrap adds the in class when the modal is open and removes it when closed

Overflow Scroll css is not working in the div

If you add height in .wrapper class then your scroll is working, without height scroll is not working.

Try this http://jsfiddle.net/ZcrFr/3/

CSS:

.wrapper {
  position: relative;
  overflow: scroll;
  width: 1000px;
  height: 800px;
}

How to write/update data into cells of existing XLSX workbook using xlsxwriter in python

Quote from xlsxwriter module documentation:

This module cannot be used to modify or write to an existing Excel XLSX file.

If you want to modify existing xlsx workbook, consider using openpyxl module.

See also:

Random Number Between 2 Double Numbers

Use a static Random or the numbers tend to repeat in tight/fast loops due to the system clock seeding them.

public static class RandomNumbers
{
    private static Random random = new Random();
    //=-------------------------------------------------------------------
    // double between min and the max number
    public static double RandomDouble(int min, int max) 
    {
        return (random.NextDouble() * (max - min)) + min;
    }
    //=----------------------------------
    // double between 0 and the max number
    public static double RandomDouble(int max) 
    {
        return (random.NextDouble() * max);
    }
    //=-------------------------------------------------------------------
    // int between the min and the max number
    public static int RandomInt(int min, int max) 
    {   
        return random.Next(min, max + 1);
    }
    //=----------------------------------
    // int between 0 and the max number
    public static int RandomInt(int max) 
    {
        return random.Next(max + 1);
    }
    //=-------------------------------------------------------------------
 }

See also : https://docs.microsoft.com/en-us/dotnet/api/system.random?view=netframework-4.8

Is it possible to have empty RequestParam values use the defaultValue?

You can set RequestParam, using generic class Integer instead of int, it will resolve your issue.

   @RequestParam(value= "i", defaultValue = "20") Integer i

How do I insert an image in an activity with android studio?

since you followed the tutorial, I presume you have a screen that says Hello World.

that means you have some code in your layout xml that looks like this

<TextView        
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

you want to display an image, so instead of TextView you want to have ImageView. and instead of a text attribute you want an src attribute, that links to your drawable resource

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/cool_pic"
/>

How to enable/disable bluetooth programmatically in android

The solution of prijin worked perfectly for me. It is just fair to mention that two additional permissions are needed:

<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>

When these are added, enabling and disabling works flawless with the default bluetooth adapter.

init-param and context-param

What is the difference between <init-param> and <context-param> !?

Single servlet versus multiple servlets.

Other Answers give details, but here is the summary:

A web app, that is, a “context”, is made up of one or more servlets.

  • <init-param> defines a value available to a single specific servlet within a context.
  • <context-param> defines a value available to all the servlets within a context.

Line Break in XML?

If you use CDATA, you could embed the line breaks directly into the XML I think. Example:

<song>
    <title>Song Title</title>
    <lyric><![CDATA[Line 1
Line 2
Line 3]]></lyric>
</song>

How to get the full URL of a Drupal page?

Maybe what you want is just plain old predefined variables.

Consider trying

$_SERVER['REQUEST_URI'']

Or read more here.

C# equivalent of C++ vector, with contiguous memory?

You could use a List<T> and when T is a value type it will be allocated in contiguous memory which would not be the case if T is a reference type.

Example:

List<int> integers = new List<int>();
integers.Add(1);
integers.Add(4);
integers.Add(7);

int someElement = integers[1];

Is there a way to get a textarea to stretch to fit its content without using PHP or JavaScript?

Another simple solution for dynamic textarea control.

_x000D_
_x000D_
<!--JAVASCRIPT-->
<script type="text/javascript">
$('textarea').on('input', function () {
            this.style.height = "";
            this.style.height = this.scrollHeight + "px";
 });
</script>
_x000D_
_x000D_
_x000D_

How to submit form on change of dropdown list?

Just ask assistance of JavaScript.

<select onchange="this.form.submit()">
    ...
</select>

See also:

How to run a subprocess with Python, wait for it to exit and get the full stdout as a string?

subprocess.check_output(...)

calls the process, raises if its error code is nonzero, and otherwise returns its stdout. It's just a quick shorthand so you don't have to worry about PIPEs and things.

"The page you are requesting cannot be served because of the extension configuration." error message

Related to Server 2016, I should add:

  1. Run this command: aspnet_regiis -lv from this dir: C:\Windows\Microsoft.NET\Framework\v2.0.50727\ This gives you the best view of what is going on

  2. On Server 2016, installing .net and iis out of sequence does not seem to be a problem.

  3. What is more likely to be a problem on Server 2016 is simply that asp.net is not installed on the machine.

How do you tell if a checkbox is selected in Selenium for Java?

I would do it with cssSelector:

// for all checked checkboxes
driver.findElements(By.cssSelector("input:checked[type='checkbox']"));
// for all notchecked checkboxes
driver.findElements(By.cssSelector("input:not(:checked)[type='checkbox']"));

Maybe that also helps ;-)

How to disable Home and other system buttons in Android?

First of, please think long and hard if you really want to disable the Home button or any other button for that matter (e.g. the Back button), this is not something that should be done (at least most of the times, this is a bad design). I can speak only for myself, but if I downloaded an app that doesn't let me do something like clicking an OS button, the next thing I do is uninstall that app and leave a very bad review. I also believe that your app will not be featured on the App Store.

Now...

Notice that MX Player is asking permission to draw on top of other applications:MX Player permissions
Since you cannot override the Home button on Android device (at least no in the latest OS versions). MX Player draws itself on top of your launcher when you "lock" the app and clicks on the Home button.
To see an example of that is a bit more simple and straight forward to understand, you can see the Facebook Messenger App.

As I was asked to provide some more info about MX Player Status Bar and Navigation Bar "overriding", I'm editing my answer to include these topics too.

First thing first, MX Player is using Immersive Full-Screen Mode (DevBytes Video) on KitKat.
Android 4.4 (API Level 19) introduces a new SYSTEM_UI_FLAG_IMMERSIVE flag for setSystemUiVisibility() that lets your app go truly "full screen." This flag, when combined with the SYSTEM_UI_FLAG_HIDE_NAVIGATION and SYSTEM_UI_FLAG_FULLSCREEN flags, hides the navigation and status bars and lets your app capture all touch events on the screen.

When immersive full-screen mode is enabled, your activity continues to receive all touch events. The user can reveal the system bars with an inward swipe along the region where the system bars normally appear. This clears the SYSTEM_UI_FLAG_HIDE_NAVIGATION flag (and the SYSTEM_UI_FLAG_FULLSCREEN flag, if applied) so the system bars become visible. This also triggers your View.OnSystemUiVisibilityChangeListener, if set. However, if you'd like the system bars to automatically hide again after a few moments, you can instead use the SYSTEM_UI_FLAG_IMMERSIVE_STICKY flag. Note that the "sticky" version of the flag doesn't trigger any listeners, as system bars temporarily shown in this mode are in a transient state.

Second: Hiding the Status Bar
Third: Hiding the Navigation Bar
Please note that although using immersive full screen is only for KitKat, hiding the Status Bar and Navigation Bar is not only for KitKat.

I don't have much to say about the 2nd and 3rd, You get the idea I believe, it's a fast read in any case. Just make sure you pay close attention to View.OnSystemUiVisibilityChangeListener.

I added a Gist that explains what I meant, it's not complete and needs some fixing but you'll get the idea. https://gist.github.com/Epsiloni/8303531

Good luck implementing this, and have fun!

How do you use "git --bare init" repository?

It is nice to verify that the code you pushed actually got committed.

You can get a log of changes on a bare repository by explicitly setting the path using the --relative option.

$ cd test_repo
$ git log --relative=/

This will show you the committed changes as if this was a regular git repo.

Android statusbar icons color

Setting windowLightStatusBar to true not works with Mi phones, some Meizu phones, Blackview phones, WileyFox etc. I've found such hack for Mi and Meizu devices. This is not a comprehensive solution of this perfomance problem, but maybe it would be useful to somebody.

And I think, it would be better to tell your customer that coloring status bar (for example) white - is not a good idea. instead of using different hacks it would be better to define appropriate colorPrimaryDark according to the guidelines

Vue component event after render

updated() should be what you're looking for:

Called after a data change causes the virtual DOM to be re-rendered and patched.

The component’s DOM will have been updated when this hook is called, so you can perform DOM-dependent operations here.

How can I check if my python object is a number?

Use Number from the numbers module to test isinstance(n, Number) (available since 2.6).

isinstance(n, numbers.Number)

Here it is in action with various kinds of numbers and one non-number:

>>> from numbers import Number
... from decimal import Decimal
... from fractions import Fraction
... for n in [2, 2.0, Decimal('2.0'), complex(2,0), Fraction(2,1), '2']:
...     print '%15s %s' % (n.__repr__(), isinstance(n, Number))
              2 True
            2.0 True
 Decimal('2.0') True
         (2+0j) True
 Fraction(2, 1) True
            '2' False

This is, of course, contrary to duck typing. If you are more concerned about how an object acts rather than what it is, perform your operations as if you have a number and use exceptions to tell you otherwise.

Rounding integer division (instead of truncating)

(Edited) Rounding integers with floating point is the easiest solution to this problem; however, depending on the problem set is may be possible. For example, in embedded systems the floating point solution may be too costly.

Doing this using integer math turns out to be kind of hard and a little unintuitive. The first posted solution worked okay for the the problem I had used it for but after characterizing the results over the range of integers it turned out to be very bad in general. Looking through several books on bit twiddling and embedded math return few results. A couple of notes. First, I only tested for positive integers, my work does not involve negative numerators or denominators. Second, and exhaustive test of 32 bit integers is computational prohibitive so I started with 8 bit integers and then mades sure that I got similar results with 16 bit integers.

I started with the 2 solutions that I had previously proposed:

#define DIVIDE_WITH_ROUND(N, D) (((N) == 0) ? 0:(((N * 10)/D) + 5)/10)

#define DIVIDE_WITH_ROUND(N, D) (N == 0) ? 0:(N - D/2)/D + 1;

My thought was that the first version would overflow with big numbers and the second underflow with small numbers. I did not take 2 things into consideration. 1.) the 2nd problem is actually recursive since to get the correct answer you have to properly round D/2. 2.) In the first case you often overflow and then underflow, the two canceling each other out. Here is an error plot of the two (incorrect) algorithms:Divide with Round1 8 bit x=numerator y=denominator

This plot shows that the first algorithm is only incorrect for small denominators (0 < d < 10). Unexpectedly it actually handles large numerators better than the 2nd version.

Here is a plot of the 2nd algorithm: 8 bit signed numbers 2nd algorithm.

As expected it fails for small numerators but also fails for more large numerators than the 1st version.

Clearly this is the better starting point for a correct version:

#define DIVIDE_WITH_ROUND(N, D) (((N) == 0) ? 0:(((N * 10)/D) + 5)/10)

If your denominators is > 10 then this will work correctly.

A special case is needed for D == 1, simply return N. A special case is needed for D== 2, = N/2 + (N & 1) // Round up if odd.

D >= 3 also has problems once N gets big enough. It turns out that larger denominators only have problems with larger numerators. For 8 bit signed number the problem points are

if (D == 3) && (N > 75))
else if ((D == 4) && (N > 100))
else if ((D == 5) && (N > 125))
else if ((D == 6) && (N > 150))
else if ((D == 7) && (N > 175))
else if ((D == 8) && (N > 200))
else if ((D == 9) && (N > 225))
else if ((D == 10) && (N > 250))

(return D/N for these)

So in general the the pointe where a particular numerator gets bad is somewhere around
N > (MAX_INT - 5) * D/10

This is not exact but close. When working with 16 bit or bigger numbers the error < 1% if you just do a C divide (truncation) for these cases.

For 16 bit signed numbers the tests would be

if ((D == 3) && (N >= 9829))
else if ((D == 4) && (N >= 13106))
else if ((D == 5) && (N >= 16382))
else if ((D == 6) && (N >= 19658))
else if ((D == 7) && (N >= 22935))
else if ((D == 8) && (N >= 26211))
else if ((D == 9) && (N >= 29487))
else if ((D == 10) && (N >= 32763))

Of course for unsigned integers MAX_INT would be replaced with MAX_UINT. I am sure there is an exact formula for determining the largest N that will work for a particular D and number of bits but I don't have any more time to work on this problem...

(I seem to be missing this graph at the moment, I will edit and add later.) This is a graph of the 8 bit version with the special cases noted above:![8 bit signed with special cases for 0 < N <= 10 3

Note that for 8 bit the error is 10% or less for all errors in the graph, 16 bit is < 0.1%.

Find all controls in WPF Window by type

To get a list of all childs of a specific type you can use:

private static IEnumerable<DependencyObject> FindInVisualTreeDown(DependencyObject obj, Type type)
{
    if (obj != null)
    {
        if (obj.GetType() == type)
        {
            yield return obj;
        }

        for (var i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
        {
            foreach (var child in FindInVisualTreeDown(VisualTreeHelper.GetChild(obj, i), type))
            {
                if (child != null)
                {
                    yield return child;
                }
            }
        }
    }

    yield break;
}

Python Requests package: Handling xml response

requests does not handle parsing XML responses, no. XML responses are much more complex in nature than JSON responses, how you'd serialize XML data into Python structures is not nearly as straightforward.

Python comes with built-in XML parsers. I recommend you use the ElementTree API:

import requests
from xml.etree import ElementTree

response = requests.get(url)

tree = ElementTree.fromstring(response.content)

or, if the response is particularly large, use an incremental approach:

    response = requests.get(url, stream=True)
    # if the server sent a Gzip or Deflate compressed response, decompress
    # as we read the raw stream:
    response.raw.decode_content = True

    events = ElementTree.iterparse(response.raw)
    for event, elem in events:
        # do something with `elem`

The external lxml project builds on the same API to give you more features and power still.

Convert time span value to format "hh:mm Am/Pm" using C#

You cannot add AM / PM to a TimeSpan. You'll anyway have to associate the TimaSpan value with DateTime if you want to display the time in 12-hour clock format.

TimeSpan is not intended to use with a 12-hour clock format, because we are talking about a time interval here.

As it says in the documentation;

A TimeSpan object represents a time interval (duration of time or elapsed time) that is measured as a positive or negative number of days, hours, minutes, seconds, and fractions of a second. The TimeSpan structure can also be used to represent the time of day, but only if the time is unrelated to a particular date. Otherwise, the DateTime or DateTimeOffset structure should be used instead.

Also Microsoft Docs describes as follows;

A TimeSpan value can be represented as [-]d.hh:mm:ss.ff, where the optional minus sign indicates a negative time interval, the d component is days, hh is hours as measured on a 24-hour clock, mm is minutes, ss is seconds, and ff is fractions of a second.

So in this case, you can display using AM/PM as follows.

TimeSpan storedTime = new TimeSpan(03,00,00);
string displayValue = new DateTime().Add(storedTime).ToString("hh:mm tt");


Side note :
Also should note that the TimeOfDay property of DateTime is a TimeSpan, where it represents

a time interval that represents the fraction of the day that has elapsed since midnight.

align text center with android

Set also android:gravity parameter in TextView to center.

For testing the effects of different layout parameters I recommend to use different background color for every element, so you can see how your layout changes with parameters like gravity, layout_gravity or others.

Is there a float input type in HTML5?

I do so

 <input id="relacionac" name="relacionac" type="number" min="0.4" max="0.7" placeholder="0,40-0,70" class="form-control input-md" step="0.01">

then, I define min in 0.4 and max in 0.7 with step 0.01: 0.4, 0.41, 0,42 ... 0.7

XPath: difference between dot and text()

There is big difference between dot (".") and text() :-

  • The dot (".") in XPath is called the "context item expression" because it refers to the context item. This could be match with a node (such as an element, attribute, or text node) or an atomic value (such as a string, number, or boolean). While text() refers to match only element text which is in string form.

  • The dot (".") notation is the current node in the DOM. This is going to be an object of type Node while Using the XPath function text() to get the text for an element only gets the text up to the first inner element. If the text you are looking for is after the inner element you must use the current node to search for the string and not the XPath text() function.

For an example :-

<a href="something.html">
  <img src="filename.gif">
  link
</a>

Here if you want to find anchor a element by using text link, you need to use dot ("."). Because if you use //a[contains(.,'link')] it finds the anchor a element but if you use //a[contains(text(),'link')] the text() function does not seem to find it.

Hope it will help you..:)

How to join two sets in one line without using "|"

Assuming you also can't use s.union(t), which is equivalent to s | t, you could try

>>> from itertools import chain
>>> set(chain(s,t))
set([1, 2, 3, 4, 5, 6])

Or, if you want a comprehension,

>>> {i for j in (s,t) for i in j}
set([1, 2, 3, 4, 5, 6])

Cannot enqueue Handshake after invoking quit

According to:

TL;DR You need to establish a new connection by calling the createConnection method after every disconnection.

and

Note: If you're serving web requests, then you shouldn't be ending connections on every request. Just create a connection on server startup and use the connection/client object to query all the time. You can listen on the error event to handle server disconnection and for reconnecting purposes. Full code here.


From:

It says:

Server disconnects

You may lose the connection to a MySQL server due to network problems, the server timing you out, or the server crashing. All of these events are considered fatal errors, and will have the err.code = 'PROTOCOL_CONNECTION_LOST'. See the Error Handling section for more information.

The best way to handle such unexpected disconnects is shown below:

function handleDisconnect(connection) {
  connection.on('error', function(err) {
    if (!err.fatal) {
      return;
    }

    if (err.code !== 'PROTOCOL_CONNECTION_LOST') {
      throw err;
    }

    console.log('Re-connecting lost connection: ' + err.stack);

    connection = mysql.createConnection(connection.config);
    handleDisconnect(connection);
    connection.connect();
  });
}

handleDisconnect(connection);

As you can see in the example above, re-connecting a connection is done by establishing a new connection. Once terminated, an existing connection object cannot be re-connected by design.

With Pool, disconnected connections will be removed from the pool freeing up space for a new connection to be created on the next getConnection call.


I have tweaked the function such that every time a connection is needed, an initializer function adds the handlers automatically:

function initializeConnection(config) {
    function addDisconnectHandler(connection) {
        connection.on("error", function (error) {
            if (error instanceof Error) {
                if (error.code === "PROTOCOL_CONNECTION_LOST") {
                    console.error(error.stack);
                    console.log("Lost connection. Reconnecting...");

                    initializeConnection(connection.config);
                } else if (error.fatal) {
                    throw error;
                }
            }
        });
    }

    var connection = mysql.createConnection(config);

    // Add handlers.
    addDisconnectHandler(connection);

    connection.connect();
    return connection;
}

Initializing a connection:

var connection = initializeConnection({
    host: "localhost",
    user: "user",
    password: "password"
});

Minor suggestion: This may not apply to everyone but I did run into a minor issue relating to scope. If the OP feels this edit was unnecessary then he/she can choose to remove it. For me, I had to change a line in initializeConnection, which was var connection = mysql.createConnection(config); to simply just

connection = mysql.createConnection(config);

The reason being that if connection is a global variable in your program, then the issue before was that you were making a new connection variable when handling an error signal. But in my nodejs code, I kept using the same global connection variable to run queries on, so the new connection would be lost in the local scope of the initalizeConnection method. But in the modification, it ensures that the global connection variable is reset This may be relevant if you're experiencing an issue known as

Cannot enqueue Query after fatal error

after trying to perform a query after losing connection and then successfully reconnecting. This may have been a typo by the OP, but I just wanted to clarify.

Creating a new directory in C

I want to write a program that (...) creates the directory and a (...) file inside of it

because this is a very common question, here is the code to create multiple levels of directories and than call fopen. I'm using a gnu extension to print the error message with printf.

void rek_mkdir(char *path) {
    char *sep = strrchr(path, '/');
    if(sep != NULL) {
        *sep = 0;
        rek_mkdir(path);
        *sep = '/';
    }
    if(mkdir(path, 0777) && errno != EEXIST)
        printf("error while trying to create '%s'\n%m\n", path); 
}

FILE *fopen_mkdir(char *path, char *mode) {
    char *sep = strrchr(path, '/');
    if(sep) { 
        char *path0 = strdup(path);
        path0[ sep - path ] = 0;
        rek_mkdir(path0);
        free(path0);
    }
    return fopen(path,mode);
}

How can you use php in a javascript function

I think you're confusing server code with client code.

JavaScript runs on the client after it has received data from the server (like a webpage).

PHP runs on the server before it sends the data.

So there are two ways with interacting with JavaScript with php.

Like above, you can generate javascript with php in the same fashion you generate HTML with php.

Or you can use an AJAX request from javascript to interact with the server. The server can respond with data and the javascript can receive that and do something with it.

I'd recommend going back to the basics and studying how HTTP works in the server-client relationship. Then study the concept of server side languages and client side languages.

Then take a tutorial with ajax, and you will start getting the concept.

Good luck, google is your friend.

VNC viewer with multiple monitors

tightVNC 2.5.X and even pre 2.5 supports multi monitor. When you connect, you get a huge virtual monitor. However, this is also has disadvantages. UltaVNC (Tho when I tried it, was buggy in this area) allows you to connect to one huge virtual monitor or just to 1 screen at a time. (With a button to cycle through them) TightVNC also plan to support such a feature.. (When , no idea) This feature is important as if you have large multi monitors and connecting over a reasonably slow link.. The screen updates are just to slow.. Cutting down to one monitor to focus on is desirable.

I like tightVNC, but UltraVNC seems to have a few more features right now..

I have found tightVNC more solid. And that is why I have stuck with it.

I would try both. They both work well, but I imagine one would suite slightly more then the other.

Inserting Data into Hive Table

this is supported from version hive 0.14

INSERT INTO TABLE pd_temp(dept,make,cost,id,asmb_city,asmb_ct,retail) VALUES('production','thailand',10,99202,'northcarolina','usa',20)

calculating the difference in months between two dates

Below is actually the most accurate way you can do it, since the definition of "1 Month" changes depending on which month it is, and non of the other answers take this into account! If you want more information about the issue which is not built into the framework, you can read this post: A Real Timespan Object With .Years & .Months (however, reading that post isn't necessary to understand and use the function below, it works 100%, without the inherent inaccuracies of the approximation others love to use - and feel free to replace the .ReverseIt function with the built-in .Reverse function you may have on your framework (it's just here for completeness).

Please note that you can get any number of dates/times accuracy, seconds & minutes, or seconds, minutes and days, anywhere up to years (which would contain 6 parts/segments). If you specify top two and it's over a year old, it will return "1 year and 3 months ago" and won't return the rest because you've requested two segments. if it's only a few hours old, then it will only return "2 hours and 1 minute ago". Of course, same rules apply if you specify 1, 2, 3, 4, 5 or 6 segmets (maxes out at 6 because seconds, minutes, hours, days, months, years only make 6 types). It will also correct grammer issues like "minutes" vs "minute" depending on if it's 1 minute or more, same for all types, and the "string" generated will always be grammatically correct.

Here are some examples for use: bAllowSegments identifies how many segments to show... ie: if 3, then return string would be (as an example)... "3 years, 2 months and 13 days" (won't include hours, minutes and seconds as the top 3 time categories are returned), if however, the date was a newer date, such as something a few days ago, specifying the same segments (3) will return "4 days, 1 hour and 13 minutes ago" instead, so it takes everything into account!

if bAllowSegments is 2 it would return "3 years and 2 months" and if 6 (maximum value) would return "3 years, 2 months, 13 days, 13 hours, 29 minutes and 9 seconds", but, be reminded that it will NEVER RETURN something like this "0 years, 0 months, 0 days, 3 hours, 2 minutes and 13 seconds ago" as it understands there is no date data in the top 3 segments and ignores them, even if you specify 6 segments, so don't worry :). Of course, if there is a segment with 0 in it, it will take that into account when forming the string, and will display as "3 days and 4 seconds ago" and ignoring the "0 hours" part! Enjoy and please comment if you like.

 Public Function RealTimeUntilNow(ByVal dt As DateTime, Optional ByVal bAllowSegments As Byte = 2) As String
  ' bAllowSegments identifies how many segments to show... ie: if 3, then return string would be (as an example)...
  ' "3 years, 2 months and 13 days" the top 3 time categories are returned, if bAllowSegments is 2 it would return
  ' "3 years and 2 months" and if 6 (maximum value) would return "3 years, 2 months, 13 days, 13 hours, 29 minutes and 9 seconds"
  Dim rYears, rMonths, rDays, rHours, rMinutes, rSeconds As Int16
  Dim dtNow = DateTime.Now
  Dim daysInBaseMonth = Date.DaysInMonth(dt.Year, dt.Month)

  rYears = dtNow.Year - dt.Year
  rMonths = dtNow.Month - dt.Month
  If rMonths < 0 Then rMonths += 12 : rYears -= 1 ' add 1 year to months, and remove 1 year from years.
  rDays = dtNow.Day - dt.Day
  If rDays < 0 Then rDays += daysInBaseMonth : rMonths -= 1
  rHours = dtNow.Hour - dt.Hour
  If rHours < 0 Then rHours += 24 : rDays -= 1
  rMinutes = dtNow.Minute - dt.Minute
  If rMinutes < 0 Then rMinutes += 60 : rHours -= 1
  rSeconds = dtNow.Second - dt.Second
  If rSeconds < 0 Then rSeconds += 60 : rMinutes -= 1

  ' this is the display functionality
  Dim sb As StringBuilder = New StringBuilder()
  Dim iSegmentsAdded As Int16 = 0

  If rYears > 0 Then sb.Append(rYears) : sb.Append(" year" & If(rYears <> 1, "s", "") & ", ") : iSegmentsAdded += 1
  If bAllowSegments = iSegmentsAdded Then GoTo parseAndReturn

  If rMonths > 0 Then sb.AppendFormat(rMonths) : sb.Append(" month" & If(rMonths <> 1, "s", "") & ", ") : iSegmentsAdded += 1
  If bAllowSegments = iSegmentsAdded Then GoTo parseAndReturn

  If rDays > 0 Then sb.Append(rDays) : sb.Append(" day" & If(rDays <> 1, "s", "") & ", ") : iSegmentsAdded += 1
  If bAllowSegments = iSegmentsAdded Then GoTo parseAndReturn

  If rHours > 0 Then sb.Append(rHours) : sb.Append(" hour" & If(rHours <> 1, "s", "") & ", ") : iSegmentsAdded += 1
  If bAllowSegments = iSegmentsAdded Then GoTo parseAndReturn

  If rMinutes > 0 Then sb.Append(rMinutes) : sb.Append(" minute" & If(rMinutes <> 1, "s", "") & ", ") : iSegmentsAdded += 1
  If bAllowSegments = iSegmentsAdded Then GoTo parseAndReturn

  If rSeconds > 0 Then sb.Append(rSeconds) : sb.Append(" second" & If(rSeconds <> 1, "s", "") & "") : iSegmentsAdded += 1

parseAndReturn:

  ' if the string is entirely empty, that means it was just posted so its less than a second ago, and an empty string getting passed will cause an error
  ' so we construct our own meaningful string which will still fit into the "Posted * ago " syntax...

  If sb.ToString = "" Then sb.Append("less than 1 second")

  Return ReplaceLast(sb.ToString.TrimEnd(" ", ",").ToString, ",", " and")

 End Function

Of course, you will need a "ReplaceLast" function, which takes a source string, and an argument specifying what needs to be replaced, and another arg specifying what you want to replace it with, and it only replaces the last occurance of that string... i've included my one if you don't have one or dont want to implement it, so here it is, it will work "as is" with no modification needed. I know the reverseit function is no longer needed (exists in .net) but the ReplaceLast and the ReverseIt func are carried over from the pre-.net days, so please excuse how dated it may look (still works 100% tho, been using em for over ten years, can guarante they are bug free)... :). cheers.

<Extension()> _ 
Public Function ReplaceLast(ByVal sReplacable As String, ByVal sReplaceWhat As String, ByVal sReplaceWith As String) As String 
    ' let empty string arguments run, incase we dont know if we are sending and empty string or not. 
    sReplacable = sReplacable.ReverseIt 
    sReplacable = Replace(sReplacable, sReplaceWhat.ReverseIt, sReplaceWith.ReverseIt, , 1) ' only does first item on reversed version! 
    Return sReplacable.ReverseIt.ToString 
End Function 

<Extension()> _ 
Public Function ReverseIt(ByVal strS As String, Optional ByVal n As Integer = -1) As String 
    Dim strTempX As String = "", intI As Integer 

    If n > strS.Length Or n = -1 Then n = strS.Length 

    For intI = n To 1 Step -1 
        strTempX = strTempX + Mid(strS, intI, 1) 
    Next intI 

    ReverseIt = strTempX + Right(strS, Len(strS) - n) 

End Function 

Return row of Data Frame based on value in a column - R

@Zelazny7's answer works, but if you want to keep ties you could do:

df[which(df$Amount == min(df$Amount)), ]

For example with the following data frame:

df <- data.frame(Name = c("A", "B", "C", "D", "E"), 
                 Amount = c(150, 120, 175, 160, 120))

df[which.min(df$Amount), ]
#   Name Amount
# 2    B    120

df[which(df$Amount == min(df$Amount)), ]
#   Name Amount
# 2    B    120
# 5    E    120

Edit: If there are NAs in the Amount column you can do:

df[which(df$Amount == min(df$Amount, na.rm = TRUE)), ]

Jupyter notebook not running code. Stuck on In [*]

I have installed jupyter with command pip3 install jupyter and have the same problem. when instead I used the command pip3 install jupyter ipython the problem was fixed.

File Upload ASP.NET MVC 3.0

to transfer to byte[] (e.g. for saving to DB):

using (MemoryStream ms = new MemoryStream()) {
    file.InputStream.CopyTo(ms);
    byte[] array = ms.GetBuffer();
}

To transfer the input stream directly into the database, without storing it in the memory you can use this class taken from here and a bit changed:

public class VarbinaryStream : Stream {
private SqlConnection _Connection;

private string _TableName;
private string _BinaryColumn;
private string _KeyColumn;
private int _KeyValue;

private long _Offset;

private SqlDataReader _SQLReader;
private long _SQLReadPosition;

private bool _AllowedToRead = false;

public VarbinaryStream(
    string ConnectionString,
    string TableName,
    string BinaryColumn,
    string KeyColumn,
    int KeyValue,
    bool AllowRead = false)
{
  // create own connection with the connection string.
  _Connection = new SqlConnection(ConnectionString);

  _TableName = TableName;
  _BinaryColumn = BinaryColumn;
  _KeyColumn = KeyColumn;
  _KeyValue = KeyValue;


  // only query the database for a result if we are going to be reading, otherwise skip.
  _AllowedToRead = AllowRead;
  if (_AllowedToRead == true)
  {
    try
    {
      if (_Connection.State != ConnectionState.Open)
        _Connection.Open();

      SqlCommand cmd = new SqlCommand(
                      @"SELECT TOP 1 [" + _BinaryColumn + @"]
                            FROM [dbo].[" + _TableName + @"]
                            WHERE [" + _KeyColumn + "] = @id",
                  _Connection);

      cmd.Parameters.Add(new SqlParameter("@id", _KeyValue));

      _SQLReader = cmd.ExecuteReader(
          CommandBehavior.SequentialAccess |
          CommandBehavior.SingleResult |
          CommandBehavior.SingleRow |
          CommandBehavior.CloseConnection);

      _SQLReader.Read();
    }
    catch (Exception e)
    {
      // log errors here
    }
  }
}

// this method will be called as part of the Stream ímplementation when we try to write to our VarbinaryStream class.
public override void Write(byte[] buffer, int index, int count)
{
  try
  {
    if (_Connection.State != ConnectionState.Open)
      _Connection.Open();

    if (_Offset == 0)
    {
      // for the first write we just send the bytes to the Column
      SqlCommand cmd = new SqlCommand(
                                  @"UPDATE [dbo].[" + _TableName + @"]
                                            SET [" + _BinaryColumn + @"] = @firstchunk 
                                        WHERE [" + _KeyColumn + "] = @id",
                              _Connection);

      cmd.Parameters.Add(new SqlParameter("@firstchunk", buffer));
      cmd.Parameters.Add(new SqlParameter("@id", _KeyValue));

      cmd.ExecuteNonQuery();

      _Offset = count;
    }
    else
    {
      // for all updates after the first one we use the TSQL command .WRITE() to append the data in the database
      SqlCommand cmd = new SqlCommand(
                              @"UPDATE [dbo].[" + _TableName + @"]
                                        SET [" + _BinaryColumn + @"].WRITE(@chunk, NULL, @length)
                                    WHERE [" + _KeyColumn + "] = @id",
                           _Connection);

      cmd.Parameters.Add(new SqlParameter("@chunk", buffer));
      cmd.Parameters.Add(new SqlParameter("@length", count));
      cmd.Parameters.Add(new SqlParameter("@id", _KeyValue));

      cmd.ExecuteNonQuery();

      _Offset += count;
    }
  }
  catch (Exception e)
  {
    // log errors here
  }
}

// this method will be called as part of the Stream ímplementation when we try to read from our VarbinaryStream class.
public override int Read(byte[] buffer, int offset, int count)
{
  try
  {
    long bytesRead = _SQLReader.GetBytes(0, _SQLReadPosition, buffer, offset, count);
    _SQLReadPosition += bytesRead;
    return (int)bytesRead;
  }
  catch (Exception e)
  {
    // log errors here
  }
  return -1;
}
public override bool CanRead
{
  get { return _AllowedToRead; }
}

protected override void Dispose(bool disposing)
{
  if (_Connection != null)
  {
    if (_Connection.State != ConnectionState.Closed)
      try { _Connection.Close();           }
      catch { }
    _Connection.Dispose();
  }
  base.Dispose(disposing);
}

#region unimplemented methods
public override bool CanSeek
{
  get { return false; }
}

public override bool CanWrite
{
  get { return true; }
}

public override void Flush()
{
  throw new NotImplementedException();
}

public override long Length
{
  get { throw new NotImplementedException(); }
}

public override long Position
{
  get
  {
    throw new NotImplementedException();
  }
  set
  {
    throw new NotImplementedException();
  }
}
public override long Seek(long offset, SeekOrigin origin)
{
  throw new NotImplementedException();
}

public override void SetLength(long value)
{
  throw new NotImplementedException();
}
#endregion unimplemented methods  }

and the usage:

  using (var filestream = new VarbinaryStream(
                            "Connection_String",
                            "Table_Name",
                            "Varbinary_Column_name",
                            "Key_Column_Name",
                            keyValueId,
                            true))
  {
    postedFile.InputStream.CopyTo(filestream);
  }

ASP.NET Core Web API Authentication

I have implemented BasicAuthenticationHandler for basic authentication so you can use it with standart attributes Authorize and AllowAnonymous.

public class BasicAuthenticationHandler : AuthenticationHandler<BasicAuthenticationOptions>
{
    protected override Task<AuthenticateResult> HandleAuthenticateAsync()
    {
        var authHeader = (string)this.Request.Headers["Authorization"];

        if (!string.IsNullOrEmpty(authHeader) && authHeader.StartsWith("basic", StringComparison.OrdinalIgnoreCase))
        {
            //Extract credentials
            string encodedUsernamePassword = authHeader.Substring("Basic ".Length).Trim();
            Encoding encoding = Encoding.GetEncoding("iso-8859-1");
            string usernamePassword = encoding.GetString(Convert.FromBase64String(encodedUsernamePassword));

            int seperatorIndex = usernamePassword.IndexOf(':', StringComparison.OrdinalIgnoreCase);

            var username = usernamePassword.Substring(0, seperatorIndex);
            var password = usernamePassword.Substring(seperatorIndex + 1);

            //you also can use this.Context.Authentication here
            if (username == "test" && password == "test")
            {
                var user = new GenericPrincipal(new GenericIdentity("User"), null);
                var ticket = new AuthenticationTicket(user, new AuthenticationProperties(), Options.AuthenticationScheme);
                return Task.FromResult(AuthenticateResult.Success(ticket));
            }
            else
            {
                return Task.FromResult(AuthenticateResult.Fail("No valid user."));
            }
        }

        this.Response.Headers["WWW-Authenticate"]= "Basic realm=\"yourawesomesite.net\"";
        return Task.FromResult(AuthenticateResult.Fail("No credentials."));
    }
}

public class BasicAuthenticationMiddleware : AuthenticationMiddleware<BasicAuthenticationOptions>
{
    public BasicAuthenticationMiddleware(
       RequestDelegate next,
       IOptions<BasicAuthenticationOptions> options,
       ILoggerFactory loggerFactory,
       UrlEncoder encoder)
       : base(next, options, loggerFactory, encoder)
    {
    }

    protected override AuthenticationHandler<BasicAuthenticationOptions> CreateHandler()
    {
        return new BasicAuthenticationHandler();
    }
}

public class BasicAuthenticationOptions : AuthenticationOptions
{
    public BasicAuthenticationOptions()
    {
        AuthenticationScheme = "Basic";
        AutomaticAuthenticate = true;
    }
}

Registration at Startup.cs - app.UseMiddleware<BasicAuthenticationMiddleware>();. With this code, you can restrict any controller with standart attribute Autorize:

[Authorize(ActiveAuthenticationSchemes = "Basic")]
[Route("api/[controller]")]
public class ValuesController : Controller

and use attribute AllowAnonymous if you apply authorize filter on application level.

Facebook share link - can you customize the message body text?

Facebook does not allow you to change the "What's on your mind?" text box, unless of course you're developing an application for use on Facebook.

The real difference between "int" and "unsigned int"

the type just tells you what the bit pattern is supposed to represent. the bits are only what you make of them. the same sequences can be interpreted in different ways.

What is the best open XML parser for C++?

Try TinyXML or IrrXML...Both are lightweight XML parsers ( I'd suggest you to use TinyXML, anyway ).

Disable Required validation attribute under certain circumstances

The cleanest way here I believe is going to disable your client side validation and on the server side you will need to:

  1. ModelState["SomeField"].Errors.Clear (in your controller or create an action filter to remove errors before the controller code is executed)
  2. Add ModelState.AddModelError from your controller code when you detect a violation of your detected issues.

Seems even a custom view model here wont solve the problem because the number of those 'pre answered' fields could vary. If they dont then a custom view model may indeed be the easiest way, but using the above technique you can get around your validations issues.

Cannot perform runtime binding on a null reference, But it is NOT a null reference

This error happens when you have a ViewBag Non-Existent in your razor code calling a method.

Controller

public ActionResult Accept(int id)
{
    return View();
}

razor:

<div class="form-group">
      @Html.LabelFor(model => model.ToId, "To", htmlAttributes: new { @class = "control-label col-md-2" })
     <div class="col-md-10">
           @Html.Flag(Model.from)
     </div>
</div>
<div class="form-group">
     <div class="col-md-10">
          <input value="@ViewBag.MaximounAmount.ToString()" />@* HERE is the error *@ 
     </div>
</div>

For some reason, the .net aren't able to show the error in the correct line.

Normally this causes a lot of wasted time.

Chrome Dev Tools - Modify javascript and reload

Great news, the fix is coming in March 2018, see this link: https://developers.google.com/web/updates/2018/01/devtools

"Local Overrides let you make changes in DevTools, and keep those changes across page loads. Previously, any changes that you made in DevTools would be lost when you reloaded the page. Local Overrides work for most file types

How it works:

  • You specify a directory where DevTools should save changes. When you make changes in DevTools, DevTools saves a copy of the modified file to your directory.
  • When you reload the page, DevTools serves the local, modified file, rather than the network resource.

To set up Local Overrides:

  1. Open the Sources panel.
  2. Open the Overrides tab.
  3. Click Setup Overrides.
  4. Select which directory you want to save your changes to.
  5. At the top of your viewport, click Allow to give DevTools read and write access to the directory.
  6. Make your changes."

UPDATE (March 19, 2018): It's live, detailed explanations here: https://developers.google.com/web/updates/2018/01/devtools#overrides

How can I clone a private GitLab repository?

If you are using Windows,

  1. make a folder and open git bash from there

  2. in the git bash,

    git clone [email protected]:Example/projectName.git

Intersect Two Lists in C#

You need to first transform data1, in your case by calling ToString() on each element.

Use this if you want to return strings.

List<int> data1 = new List<int> {1,2,3,4,5};
List<string> data2 = new List<string>{"6","3"};

var newData = data1.Select(i => i.ToString()).Intersect(data2);

Use this if you want to return integers.

List<int> data1 = new List<int> {1,2,3,4,5};
List<string> data2 = new List<string>{"6","3"};

var newData = data1.Intersect(data2.Select(s => int.Parse(s));

Note that this will throw an exception if not all strings are numbers. So you could do the following first to check:

int temp;
if(data2.All(s => int.TryParse(s, out temp)))
{
    // All data2 strings are int's
}

Handling warning for possible multiple enumeration of IEnumerable

First off, that warning does not always mean so much. I usually disabled it after making sure it's not a performance bottle neck. It just means the IEnumerable is evaluated twice, wich is usually not a problem unless the evaluation itself takes a long time. Even if it does take a long time, in this case your only using one element the first time around.

In this scenario you could also exploit the powerful linq extension methods even more.

var firstObject = objects.First();
return DoSomeThing(firstObject).Concat(DoSomeThingElse(objects).ToList();

It is possible to only evaluate the IEnumerable once in this case with some hassle, but profile first and see if it's really a problem.

Need to combine lots of files in a directory

Assuming these are text files (since you are using notepad++) and that you are on Windows, you could fashion a simple batch script to concatenate them together.

For example, in the directory with all the text files, execute the following:

for %f in (*.txt) do type "%f" >> combined.txt

This will merge all files matching *.txt into one file called combined.txt.

For more information:

http://www.howtogeek.com/howto/keyboard-ninja/keyboard-ninja-concatenate-multiple-text-files-in-windows/

convert php date to mysql format

PHP 5.3 has functions to create and reformat at DateTime object from whatever format you specify:

$mysql_date = "2012-01-02";   // date in Y-m-d format as MySQL stores it
$date_obj = date_create_from_format('Y-m-d',$mysql_date);
$date = date_format($date_obj, 'm/d/Y');
echo $date;

Outputs:

01/02/2012

MySQL can also control the formatting by using the STR_TO_DATE() function when inserting/updating, and the DATE_FORMAT() when querying.

$php_date = "01/02/2012";
$update_query = "UPDATE `appointments` SET `start_time` = STR_TO_DATE('" . $php_date . "', '%m/%d/%Y')";
$query = "SELECT DATE_FORMAT(`start_time`,'%m/%d/%Y') AS `start_time` FROM `appointments`";

Change a column type from Date to DateTime during ROR migration

First in your terminal:

rails g migration change_date_format_in_my_table

Then in your migration file:

For Rails >= 3.2:

class ChangeDateFormatInMyTable < ActiveRecord::Migration
  def up
    change_column :my_table, :my_column, :datetime
  end

  def down
    change_column :my_table, :my_column, :date
  end
end

Socket accept - "Too many open files"

When your program has more open descriptors than the open files ulimit (ulimit -a will list this), the kernel will refuse to open any more file descriptors. Make sure you don't have any file descriptor leaks - for example, by running it for a while, then stopping and seeing if any extra fds are still open when it's idle - and if it's still a problem, change the nofile ulimit for your user in /etc/security/limits.conf

How to iterate through LinkedHashMap with lists as values

I'm assuming you have a typo in your get statement and that it should be test1.get(key). If so, I'm not sure why it is not returning an ArrayList unless you are not putting in the correct type in the map in the first place.

This should work:

// populate the map
Map<String, List<String>> test1 = new LinkedHashMap<String, List<String>>();
test1.put("key1", new ArrayList<String>());
test1.put("key2", new ArrayList<String>());

// loop over the set using an entry set
for( Map.Entry<String,List<String>> entry : test1.entrySet()){
  String key = entry.getKey();
  List<String>value = entry.getValue();
  // ...
}

or you can use

// second alternative - loop over the keys and get the value per key
for( String key : test1.keySet() ){
  List<String>value = test1.get(key);
  // ...
}

You should use the interface names when declaring your vars (and in your generic params) unless you have a very specific reason why you are defining using the implementation.

Package php5 have no installation candidate (Ubuntu 16.04)

You must use prefix "php5.6-" instead of "php5-" as in ubuntu 14.04 and olders:

sudo apt-get install php5.6 php5.6-mcrypt

Count unique values with pandas per groups

Generally to count distinct values in single column, you can use Series.value_counts:

df.domain.value_counts()

#'vk.com'          5
#'twitter.com'     2
#'facebook.com'    1
#'google.com'      1
#Name: domain, dtype: int64

To see how many unique values in a column, use Series.nunique:

df.domain.nunique()
# 4

To get all these distinct values, you can use unique or drop_duplicates, the slight difference between the two functions is that unique return a numpy.array while drop_duplicates returns a pandas.Series:

df.domain.unique()
# array(["'vk.com'", "'twitter.com'", "'facebook.com'", "'google.com'"], dtype=object)

df.domain.drop_duplicates()
#0          'vk.com'
#2     'twitter.com'
#4    'facebook.com'
#6      'google.com'
#Name: domain, dtype: object

As for this specific problem, since you'd like to count distinct value with respect to another variable, besides groupby method provided by other answers here, you can also simply drop duplicates firstly and then do value_counts():

import pandas as pd
df.drop_duplicates().domain.value_counts()

# 'vk.com'          3
# 'twitter.com'     2
# 'facebook.com'    1
# 'google.com'      1
# Name: domain, dtype: int64

How to count the number of words in a sentence, ignoring numbers, punctuation and whitespace?

You can use regex.findall():

import re
line = " I am having a very nice day."
count = len(re.findall(r'\w+', line))
print (count)

How do I run a PowerShell script when the computer starts?

You can see scripts and more scheduled for startup inside Task Manager in the Startup tab. Here is how to add a new item to the scheduled startup items.

First, open up explorer to shell:startup location via start-button => run:

explorer shell:startup

Right click in that folder and in the context menu select a new shortcut. Enter the following:

C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -NoProfile -Command "C:\myfolder\somescript.ps1"

This will startup a Powershell script without starting up your $profile scripts for faster execution. This will make sure that the powershell script is started up.

The shell:startup folder is in:

$env:APPDATA\Microsoft\Windows

And then into the folder:

Start Menu\Programs\Startup

As usual, Microsoft makes things a bit cumbersome for us when a path contains spaces, so you have to put quotes around the full path or just hit tab inside Powershell to autocomplete in this case.

notifyDataSetChanged example

For an ArrayAdapter, notifyDataSetChanged only works if you use the add(), insert(), remove(), and clear() on the Adapter.

When an ArrayAdapter is constructed, it holds the reference for the List that was passed in. If you were to pass in a List that was a member of an Activity, and change that Activity member later, the ArrayAdapter is still holding a reference to the original List. The Adapter does not know you changed the List in the Activity.

Your choices are:

  1. Use the functions of the ArrayAdapter to modify the underlying List (add(), insert(), remove(), clear(), etc.)
  2. Re-create the ArrayAdapter with the new List data. (Uses a lot of resources and garbage collection.)
  3. Create your own class derived from BaseAdapter and ListAdapter that allows changing of the underlying List data structure.
  4. Use the notifyDataSetChanged() every time the list is updated. To call it on the UI-Thread, use the runOnUiThread() of Activity. Then, notifyDataSetChanged() will work.

Android API 21 Toolbar Padding

In case someone else stumbles here... you can set padding as well, for instance:

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);

int padding = 200 // padding left and right

toolbar.setPadding(padding, toolbar.getPaddingTop(), padding, toolbar.getPaddingBottom());

Or contentInset:

toolbar.setContentInsetsAbsolute(toolbar.getContentInsetLeft(), 200);

Angular - "has no exported member 'Observable'"

use return Observable.of(HEROES);

Get the first element of an array

Also worth bearing in mind is the context in which you're doing this, as an exhaustive check can be expensive and not always necessary.

For example, this solution works fine for the situation in which I'm using it (but obviously it can't be relied on in all cases...)

 /**
 * A quick and dirty way to determine whether the passed in array is associative or not, assuming that either:<br/>
 * <br/>
 * 1) All the keys are strings - i.e. associative<br/>
 * or<br/>
 * 2) All the keys are numeric - i.e. not associative<br/>
 *
 * @param array $objects
 * @return boolean
 */
private function isAssociativeArray(array $objects)
{
    // This isn't true in the general case, but it's a close enough (and quick) approximation for the context in
    // which we're using it.

    reset($objects);
    return count($objects) > 0 && is_string(key($objects));
}

SQL update from one Table to another based on a ID match

This will allow you to update a table based on the column value not being found in another table.

    UPDATE table1 SET table1.column = 'some_new_val' WHERE table1.id IN (
            SELECT * 
            FROM (
                    SELECT table1.id
                    FROM  table1 
                    LEFT JOIN table2 ON ( table2.column = table1.column ) 
                    WHERE table1.column = 'some_expected_val'
                    AND table12.column IS NULL
            ) AS Xalias
    )

This will update a table based on the column value being found in both tables.

    UPDATE table1 SET table1.column = 'some_new_val' WHERE table1.id IN (
            SELECT * 
            FROM (
                    SELECT table1.id
                    FROM  table1 
                    JOIN table2 ON ( table2.column = table1.column ) 
                    WHERE table1.column = 'some_expected_val'
            ) AS Xalias
    )

getActivity() returns null in Fragment function

Do as follows. I think it will be helpful to you.

private boolean isVisibleToUser = false;
private boolean isExecutedOnce = false;


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View root = inflater.inflate(R.layout.fragment_my, container, false);
    if (isVisibleToUser && !isExecutedOnce) {
        executeWithActivity(getActivity());
    }
    return root;
}

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    super.setUserVisibleHint(isVisibleToUser);
    this.isVisibleToUser = isVisibleToUser;
    if (isVisibleToUser && getActivity()!=null) {
        isExecutedOnce =true;
        executeWithActivity(getActivity());
    }
}


private void executeWithActivity(Activity activity){
    //Do what you have to do when page is loaded with activity

}

How to present a modal atop the current view in Swift

The only way I able to get this to work was by doing this on the presenting view controller:

    func didTapButton() {
    self.definesPresentationContext = true
    self.modalTransitionStyle = .crossDissolve
    let yourVC = self.storyboard?.instantiateViewController(withIdentifier: "YourViewController") as! YourViewController
    let navController = UINavigationController(rootViewController: yourVC)
    navController.modalPresentationStyle = .overCurrentContext
    navController.modalTransitionStyle = .crossDissolve
    self.present(navController, animated: true, completion: nil)
}

Get source jar files attached to Eclipse for Maven-managed dependencies

If the source jars are in the local repository and you are using Eclipses maven support the sources are getting automatically attached. You can run mvn dependency:sources to download all source jars for a given project. Not sure how to do the same with the documentation though.

How to config Tomcat to serve images from an external folder outside webapps?

Instead of configuring Tomcat to redirect requests, use Apache as a frontend with the Apache Tomcat connector so that Apache is only serving static content, while asking tomcat for dynamic content.

Using the JKmount directive (or others) you could specify exactly which requests are sent to Tomcat.

Requests for static content, such as images, would be served directly by Apache, using a standard virtual host configuration, while other requests, defined in the JKMount directive will be sent to Tomcat workers.

I think this implementation would give you the most flexibility and control on the overall application.

Reliable way for a Bash script to get the full path to itself

If we use Bash I believe this is the most convenient way as it doesn't require calls to any external commands:

THIS_PATH="${BASH_SOURCE[0]}";
THIS_DIR=$(dirname $THIS_PATH)

Specify JDK for Maven to use

Yet another alternative to manage multiple jdk versions is jEnv

After installation, you can simply change java version "locally" i.e. for a specific project directory by:

jenv local 1.6

This will also make mvn use that version locally, when you enable the mvn plugin:

jenv enable-plugin maven

How do I configure Maven for offline development?

If you're using IntelliJ, you can simply go to Preferences -> Build, Execution, Deployment -> Build Tools -> Maven and check/uncheck Work offline.

Handling exceptions from Java ExecutorService tasks

I got around it by wrapping the supplied runnable submitted to the executor.

CompletableFuture.runAsync(() -> {
        try {
              runnable.run();
        } catch (Throwable e) {
              Log.info(Concurrency.class, "runAsync", e);
        }
}, executorService);

How do I remove a substring from the end of a string in Python?

Depends on what you know about your url and exactly what you're tryinh to do. If you know that it will always end in '.com' (or '.net' or '.org') then

 url=url[:-4]

is the quickest solution. If it's a more general URLs then you're probably better of looking into the urlparse library that comes with python.

If you on the other hand you simply want to remove everything after the final '.' in a string then

url.rsplit('.',1)[0]

will work. Or if you want just want everything up to the first '.' then try

url.split('.',1)[0]

MySQL Stored procedure variables from SELECT statements

Corrected a few things and added an alternative select - delete as appropriate.

DELIMITER |

CREATE PROCEDURE getNearestCities
(
IN p_cityID INT -- should this be int unsigned ?
)
BEGIN

DECLARE cityLat FLOAT; -- should these be decimals ?
DECLARE cityLng FLOAT;

    -- method 1
    SELECT lat,lng into cityLat, cityLng FROM cities WHERE cities.cityID = p_cityID;

    SELECT 
     b.*, 
     HAVERSINE(cityLat,cityLng, b.lat, b.lng) AS dist 
    FROM 
     cities b 
    ORDER BY 
     dist 
    LIMIT 10;

    -- method 2
    SELECT   
      b.*, 
      HAVERSINE(a.lat, a.lng, b.lat, b.lng) AS dist
    FROM     
      cities AS a
    JOIN cities AS b on a.cityID = p_cityID
    ORDER BY 
      dist
    LIMIT 10;

END |

delimiter ;

"Non-resolvable parent POM: Could not transfer artifact" when trying to refer to a parent pom from a child pom with ${parent.groupid}

As Nayan said the Path has to updated properly in my case the apache-maven was installed in C:\apache-maven and settings.xml was found inside C:\apache-maven\conf\settings.xml

if this doesn't work go to your local repos
in my case C:\Users\<<"name">>.m2\
and search for .lastUpdated and delete them
then build the maven

How to restart VScode after editing extension's config?

You can do the following

  1. Click on extensions
  2. Type Reload
  3. Then install

It will add a reload button on your right hand at the bottom of the vs code.

How to find encoding of a file via script on Linux?

You can extract encoding of a single file with the file command. I have a sample.html file with:

$ file sample.html 

sample.html: HTML document, UTF-8 Unicode text, with very long lines

$ file -b sample.html

HTML document, UTF-8 Unicode text, with very long lines

$ file -bi sample.html

text/html; charset=utf-8

$ file -bi sample.html  | awk -F'=' '{print $2 }'

utf-8

Where does Oracle SQL Developer store connections?

It is stored in a file called connections.xml under

\Users\[User]\AppData\Roaming\SQL Developer\System\

When I renamed the file, all my connection info went away. I renamed it back, and it all came back. When I viewed the XML file, I found both test connection aliases, ports, usernames, roles, authentication types, etc.

How to delete an SVN project from SVN repository

"Obliberating" contents from a svn repository, i.e. wiping this contents from the disc, can be done as described in this article http://www.limilabs.com/blog/how-to-permanently-remove-svn-folder

It requires access to the server side svn repository, thus you must have some admin privileges.

It works by (a) dumping the repository content into a file, (b) excluding some contents and (c) wiping and re-creating the plain repository again and eventually by (d) loading the filtered repository contents:

svnadmin dump "path/to/svnrepo" > svnrepo.txt                    // (a)
svndumpfilter exclude "my/folder" < svnrepo.txt > filtered.txt   // (b)
rm -rf "path/to/svnrepo" && svnadmin create "path/to/svnrepo"    // (c)
svnadmin load "path/to/svnrepo" < filtered.txt                   // (d)

The repository counter is unchanged by this operations. However, your repository is now "missing" all those revision numbers used to create that contents you removed in step (b).

Subversion 1.7.5 appears to handle this "missing" revisions pretty well. Using "svn ls -r $missing" for example, reports the very same as "svn ls -r $(( missing - 1))".

Contrary to this, my (pretty old) VIEWVC reports "no contents" when querying a "missing" revision.

Fastest way to remove first char in a String

You could profile it, if you really cared. Write a loop of many iterations and see what happens. Chances are, however, that this is not the bottleneck in your application, and TrimStart seems the most semantically correct. Strive to write code readably before optimizing.

How to add image in Flutter

How to include images in your app

1. Create an assets/images folder

  • This should be located in the root of your project, in the same folder as your pubspec.yaml file.
  • In Android Studio you can right click in the Project view
  • You don't have to call it assets or images. You don't even need to make images a subfolder. Whatever name you use, though, is what you will regester in the pubspec.yaml file.

2. Add your image to the new folder

  • You can just copy your image into assets/images. The relative path of lake.jpg, for example, would be assets/images/lake.jpg.

3. Register the assets folder in pubspec.yaml

  • Open the pubspec.yaml file that is in the root of your project.

  • Add an assets subsection to the flutter section like this:

      flutter:
        assets:
          - assets/images/lake.jpg
    
  • If you have multiple images that you want to include then you can leave off the file name and just use the directory name (include the final /):

      flutter:
        assets:
          - assets/images/
    

4. Use the image in code

  • Get the asset in an Image widget with Image.asset('assets/images/lake.jpg').

  • The entire main.dart file is here:

      import 'package:flutter/material.dart';
    
      void main() => runApp(MyApp());
    
      class MyApp extends StatelessWidget {
        @override
        Widget build(BuildContext context) {
          return MaterialApp(
            home: Scaffold(
              appBar: AppBar(
                title: Text("Image from assets"),
              ),
              body: Image.asset('assets/images/lake.jpg'), //   <--- image
            ),
          );
        }
      }
    

5. Restart your app

When making changes to pubspec.yaml I find that I often need to completely stop my app and restart it again, especially when adding assets. Otherwise I get a crash.

Running the app now you should have something like this:

enter image description here

Further reading

  • See the documentation for how to do things like provide alternate images for different densities.

Videos

The first video here goes into a lot of detail about how to include images in your app. The second video covers more about how to adjust how they look.

How to retrieve the last autoincremented ID from a SQLite table?

I've had issues with using SELECT last_insert_rowid() in a multithreaded environment. If another thread inserts into another table that has an autoinc, last_insert_rowid will return the autoinc value from the new table.

Here's where they state that in the doco:

If a separate thread performs a new INSERT on the same database connection while the sqlite3_last_insert_rowid() function is running and thus changes the last insert rowid, then the value returned by sqlite3_last_insert_rowid() is unpredictable and might not equal either the old or the new last insert rowid.

That's from sqlite.org doco

Access Https Rest Service using Spring RestTemplate

KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
keyStore.load(new FileInputStream(new File(keyStoreFile)),
  keyStorePassword.toCharArray());

SSLConnectionSocketFactory socketFactory = new SSLConnectionSocketFactory(
  new SSLContextBuilder()
    .loadTrustMaterial(null, new TrustSelfSignedStrategy())
    .loadKeyMaterial(keyStore, keyStorePassword.toCharArray())
    .build(),
    NoopHostnameVerifier.INSTANCE);

HttpClient httpClient = HttpClients.custom().setSSLSocketFactory(
  socketFactory).build();

ClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(
  httpClient);
RestTemplate restTemplate = new RestTemplate(requestFactory);
MyRecord record = restTemplate.getForObject(uri, MyRecord.class);
LOG.debug(record.toString());

Material effect on button with background color

There are two approaches explained in the great tutorial be Alex Lockwood: http://www.androiddesignpatterns.com/2016/08/coloring-buttons-with-themeoverlays-background-tints.html:

Approach #1: Modifying the button’s background color w/ a ThemeOverlay

<!-- res/values/themes.xml -->
<style name="RedButtonLightTheme" parent="ThemeOverlay.AppCompat.Light">
    <item name="colorAccent">@color/googred500</item>
</style>

<Button
    style="@style/Widget.AppCompat.Button.Colored"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:theme="@style/RedButtonLightTheme"/>

Approach #2: Setting the AppCompatButton’s background tint

<!-- res/color/btn_colored_background_tint.xml -->
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <!-- Disabled state. -->
    <item android:state_enabled="false"
          android:color="?attr/colorButtonNormal"
          android:alpha="?android:attr/disabledAlpha"/>

    <!-- Enabled state. -->
    <item android:color="?attr/colorAccent"/>

</selector>

<android.support.v7.widget.AppCompatButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:backgroundTint="@color/btn_colored_background_tint"/>

How to set label size in Bootstrap

In Bootstrap 3 they do not have separate classes for different styles of labels.

http://getbootstrap.com/components/

However, you can customize bootstrap classes that way. In your css file

.lb-sm {
  font-size: 12px;
}

.lb-md {
  font-size: 16px;
}

.lb-lg {
  font-size: 20px;
}

Alternatively, you can use header tags to change the sizes. For example, here is a medium sized label and a small-sized label

_x000D_
_x000D_
<link href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<h3>Example heading <span class="label label-default">New</span></h3>_x000D_
<h6>Example heading <span class="label label-default">New</span></h6>
_x000D_
_x000D_
_x000D_

They might add size classes for labels in future Bootstrap versions.

What are the complexity guarantees of the standard containers?

I found the nice resource Standard C++ Containers. Probably this is what you all looking for.

VECTOR

Constructors

vector<T> v;              Make an empty vector.                                     O(1)
vector<T> v(n);           Make a vector with N elements.                            O(n)
vector<T> v(n, value);    Make a vector with N elements, initialized to value.      O(n)
vector<T> v(begin, end);  Make a vector and copy the elements from begin to end.    O(n)

Accessors

v[i]          Return (or set) the I'th element.                        O(1)
v.at(i)       Return (or set) the I'th element, with bounds checking.  O(1)
v.size()      Return current number of elements.                       O(1)
v.empty()     Return true if vector is empty.                          O(1)
v.begin()     Return random access iterator to start.                  O(1)
v.end()       Return random access iterator to end.                    O(1)
v.front()     Return the first element.                                O(1)
v.back()      Return the last element.                                 O(1)
v.capacity()  Return maximum number of elements.                       O(1)

Modifiers

v.push_back(value)         Add value to end.                                                O(1) (amortized)
v.insert(iterator, value)  Insert value at the position indexed by iterator.                O(n)
v.pop_back()               Remove value from end.                                           O(1)
v.assign(begin, end)       Clear the container and copy in the elements from begin to end.  O(n)
v.erase(iterator)          Erase value indexed by iterator.                                 O(n)
v.erase(begin, end)        Erase the elements from begin to end.                            O(n)

For other containers, refer to the page.

How to Create an excel dropdown list that displays text with a numeric hidden value

Data validation drop down

There is a list option in Data validation. If this is combined with a VLOOKUP formula you would be able to convert the selected value into a number.

The steps in Excel 2010 are:

  • Create your list with matching values.
  • On the Data tab choose Data Validation
  • The Data validation form will be displayed
  • Set the Allow dropdown to List
  • Set the Source range to the first part of your list
  • Click on OK (User messages can be added if required)

In a cell enter a formula like this

=VLOOKUP(A2,$D$3:$E$5,2,FALSE)

which will return the matching value from the second part of your list.

Screenshot of Data validation list

Form control drop down

Alternatively, Form controls can be placed on a worksheet. They can be linked to a range and return the position number of the selected value to a specific cell.

The steps in Excel 2010 are:

  • Create your list of data in a worksheet
  • Click on the Developer tab and dropdown on the Insert option
  • In the Form section choose Combo box or List box
  • Use the mouse to draw the box on the worksheet
  • Right click on the box and select Format control
  • The Format control form will be displayed
  • Click on the Control tab
  • Set the Input range to your list of data
  • Set the Cell link range to the cell where you want the number of the selected item to appear
  • Click on OK

Screenshot of form control

How to create and download a csv file from php script?

That is the function that I used for my project, and it works as expected.

function array_csv_download( $array, $filename = "export.csv", $delimiter=";" )
{
    header( 'Content-Type: application/csv' );
    header( 'Content-Disposition: attachment; filename="' . $filename . '";' );

    // clean output buffer
    ob_end_clean();

    $handle = fopen( 'php://output', 'w' );

    // use keys as column titles
    fputcsv( $handle, array_keys( $array['0'] ) );

    foreach ( $array as $value ) {
        fputcsv( $handle, $value , $delimiter );
    }

    fclose( $handle );

    // flush buffer
    ob_flush();

    // use exit to get rid of unexpected output afterward
    exit();
}

What is the difference between #import and #include in Objective-C?

There seems to be a lot of confusion regarding the preprocessor.

What the compiler does when it sees a #include that it replaces that line with the contents of the included files, no questions asked.

So if you have a file a.h with this contents:

typedef int my_number;

and a file b.c with this content:

#include "a.h"
#include "a.h"

the file b.c will be translated by the preprocessor before compilation to

typedef int my_number;
typedef int my_number;

which will result in a compiler error, since the type my_number is defined twice. Even though the definition is the same this is not allowed by the C language.

Since a header often is used in more than one place include guards usually are used in C. This looks like this:

 #ifndef _a_h_included_
 #define _a_h_included_

 typedef int my_number;

 #endif

The file b.c still would have the whole contents of the header in it twice after being preprocessed. But the second instance would be ignored since the macro _a_h_included_ would already have been defined.

This works really well, but has two drawbacks. First of all the include guards have to be written, and the macro name has to be different in every header. And secondly the compiler has still to look for the header file and read it as often as it is included.

Objective-C has the #import preprocessor instruction (it also can be used for C and C++ code with some compilers and options). This does almost the same as #include, but it also notes internally which file has already been included. The #import line is only replaced by the contents of the named file for the first time it is encountered. Every time after that it is just ignored.

Appending an id to a list if not already present in a string

Your list just contains a string. Convert it to integer IDs:

L = ['350882 348521 350166\r\n']

ids = [int(i) for i in L[0].strip().split()]
print(ids)
id = 348521
if id not in ids:
    ids.append(id)
print(ids)
id = 348522
if id not in ids:
    ids.append(id)
print(ids)
# Turn it back into your odd format
L = [' '.join(str(id) for id in ids) + '\r\n']
print(L)

Output:

[350882, 348521, 350166]
[350882, 348521, 350166]
[350882, 348521, 350166, 348522]
['350882 348521 350166 348522\r\n']

What exactly does stringstream do?

You entered an alphanumeric and int, blank delimited in mystr.

You then tried to convert the first token (blank delimited) into an int.

The first token was RS which failed to convert to int, leaving a zero for myprice, and we all know what zero times anything yields.

When you only entered int values the second time, everything worked as you expected.

It was the spurious RS that caused your code to fail.

How can I break from a try/catch block without throwing an exception in Java

Various ways:

  • return
  • break or continue when in a loop
  • break to label when in a labeled statement (see @aioobe's example)
  • break when in a switch statement.

...

  • System.exit() ... though that's probably not what you mean.

In my opinion, "break to label" is the most natural (least contorted) way to do this if you just want to get out of a try/catch. But it could be confusing to novice Java programmers who have never encountered that Java construct.

But while labels are obscure, in my opinion wrapping the code in a do ... while (false) so that you can use a break is a worse idea. This will confuse non-novices as well as novices. It is better for novices (and non-novices!) to learn about labeled statements.


By the way, return works in the case where you need to break out of a finally. But you should avoid doing a return in a finally block because the semantics are a bit confusing, and liable to give the reader a headache.

MySQL parameterized queries

As an alternative to the chosen answer, and with the same safe semantics of Marcel's, here is a compact way of using a Python dictionary to specify the values. It has the benefit of being easy to modify as you add or remove columns to insert:

  meta_cols=('SongName','SongArtist','SongAlbum','SongGenre')
  insert='insert into Songs ({0}) values ({1})'.
        .format(','.join(meta_cols), ','.join( ['%s']*len(meta_cols) ))
  args = [ meta[i] for i in meta_cols ]
  cursor=db.cursor()
  cursor.execute(insert,args)
  db.commit()

Where meta is the dictionary holding the values to insert. Update can be done in the same way:

  meta_cols=('SongName','SongArtist','SongAlbum','SongGenre')
  update='update Songs set {0} where id=%s'.
        .format(','.join([ '{0}=%s'.format(c) for c in meta_cols ]))
  args = [ meta[i] for i in meta_cols ]
  args.append( songid )
  cursor=db.cursor()
  cursor.execute(update,args)
  db.commit()

Easiest way to mask characters in HTML(5) text input

Look up the new HTML5 Input Types. These instruct browsers to perform client-side filtering of data, but the implementation is incomplete across different browsers. The pattern attribute will do regex-style filtering, but, again, browsers don't fully (or at all) support it.

However, these won't block the input itself, it will simply prevent submitting the form with the invalid data. You'll still need to trap the onkeydown event to block key input before it displays on the screen.

How can I select random files from a directory in bash?

I use this: it uses temporary file but goes deeply in a directory until it find a regular file and return it.

# find for a quasi-random file in a directory tree:

# directory to start search from:
ROOT="/";  

tmp=/tmp/mytempfile    
TARGET="$ROOT"
FILE=""; 
n=
r=
while [ -e "$TARGET" ]; do 
    TARGET="$(readlink -f "${TARGET}/$FILE")" ; 
    if [ -d "$TARGET" ]; then
      ls -1 "$TARGET" 2> /dev/null > $tmp || break;
      n=$(cat $tmp | wc -l); 
      if [ $n != 0 ]; then
        FILE=$(shuf -n 1 $tmp)
# or if you dont have/want to use shuf:
#       r=$(($RANDOM % $n)) ; 
#       FILE=$(tail -n +$(( $r + 1 ))  $tmp | head -n 1); 
      fi ; 
    else
      if [ -f "$TARGET"  ] ; then
        rm -f $tmp
        echo $TARGET
        break;
      else 
        # is not a regular file, restart:
        TARGET="$ROOT"
        FILE=""
      fi
    fi
done;

Convert data.frame column to a vector?

I'm going to attempt to explain this without making any mistakes, but I'm betting this will attract a clarification or two in the comments.

A data frame is a list. When you subset a data frame using the name of a column and [, what you're getting is a sublist (or a sub data frame). If you want the actual atomic column, you could use [[, or somewhat confusingly (to me) you could do aframe[,2] which returns a vector, not a sublist.

So try running this sequence and maybe things will be clearer:

avector <- as.vector(aframe['a2'])
class(avector) 

avector <- aframe[['a2']]
class(avector)

avector <- aframe[,2]
class(avector)

@Autowired - No qualifying bean of type found for dependency at least 1 bean

In your controller class, just add @ComponentScan("package") annotation. In my case the package name is com.shoppingcart.So i wrote the code as @ComponentScan("com.shoppingcart") and it worked for me.

How to read a value from the Windows registry

Typically the register key and value are constants in the program. If so, here is an example how to read a DWORD registry value Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\LongPathsEnabled:

#include <windows.h>

DWORD val;
DWORD dataSize = sizeof(val);
if (ERROR_SUCCESS == RegGetValueA(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Control\\FileSystem", "LongPathsEnabled", RRF_RT_DWORD, nullptr /*type not required*/, &val, &dataSize)) {
  printf("Value is %i\n", val);
  // no CloseKey needed because it is a predefined registry key
}
else {
  printf("Error reading.\n");
}

To adapt for other value types, see https://docs.microsoft.com/en-us/windows/win32/api/winreg/nf-winreg-reggetvaluea for complete spec.

How can I capture the right-click event in JavaScript?

I think that you are looking for something like this:

   function rightclick() {
    var rightclick;
    var e = window.event;
    if (e.which) rightclick = (e.which == 3);
    else if (e.button) rightclick = (e.button == 2);
    alert(rightclick); // true or false, you can trap right click here by if comparison
}

(http://www.quirksmode.org/js/events_properties.html)

And then use the onmousedown even with the function rightclick() (if you want to use it globally on whole page you can do this <body onmousedown=rightclick(); >

Find a commit on GitHub given the commit hash

A URL of the form https://github.com/<owner>/<project>/commit/<hash> will show you the changes introduced in that commit. For example here's a recent bugfix I made to one of my projects on GitHub:

https://github.com/jerith666/git-graph/commit/35e32b6a00dec02ae7d7c45c6b7106779a124685

You can also shorten the hash to any unique prefix, like so:

https://github.com/jerith666/git-graph/commit/35e32b


I know you just asked about GitHub, but for completeness: If you have the repository checked out, from the command line, you can achieve basically the same thing with either of these commands (unique prefixes work here too):

git show 35e32b6a00dec02ae7d7c45c6b7106779a124685
git log -p -1 35e32b6a00dec02ae7d7c45c6b7106779a124685

Note: If you shorten the commit hash too far, the command line gives you a helpful disambiguation message, but GitHub will just return a 404.

ORA-00060: deadlock detected while waiting for resource

I was testing a function that had multiple UPDATE statements within IF-ELSE blocks.

I was testing all possible paths, so I reset the tables to their previous values with 'manual' UPDATE statements each time before running the function again.

I noticed that the issue would happen just after those UPDATE statements;

I added a COMMIT; after the UPDATE statement I used to reset the tables and that solved the problem.

So, caution, the problem was not the function itself...

process.env.NODE_ENV is undefined

We ran into this problem when working with node on Windows.

Rather than requiring anyone who attempts to run the app to set these variables, we provided a fallback within the application.

var environment = process.env.NODE_ENV || 'development';

In a production environment, we would define it per the usual methods (SET/export).

Error: " 'dict' object has no attribute 'iteritems' "

The purpose of .iteritems() was to use less memory space by yielding one result at a time while looping. I am not sure why Python 3 version does not support iteritems()though it's been proved to be efficient than .items()

If you want to include a code that supports both the PY version 2 and 3,

try:
    iteritems
except NameError:
    iteritems = items

This can help if you deploy your project in some other system and you aren't sure about the PY version.

Why when a constructor is annotated with @JsonCreator, its arguments must be annotated with @JsonProperty?

Jackson has to know in what order to pass fields from a JSON object to the constructor. It is not possible to access parameter names in Java using reflection - that's why you have to repeat this information in annotations.

How to convert std::chrono::time_point to calendar datetime string with fractional seconds?

If system_clock, this class have time_t conversion.

#include <iostream>
#include <chrono>
#include <ctime>

using namespace std::chrono;

int main()
{
  system_clock::time_point p = system_clock::now();

  std::time_t t = system_clock::to_time_t(p);
  std::cout << std::ctime(&t) << std::endl; // for example : Tue Sep 27 14:21:13 2011
}

example result:

Thu Oct 11 19:10:24 2012

EDIT: But, time_t does not contain fractional seconds. Alternative way is to use time_point::time_since_epoch() function. This function returns duration from epoch. Follow example is milli second resolution's fractional.

#include <iostream>
#include <chrono>
#include <ctime>

using namespace std::chrono;

int main()
{
  high_resolution_clock::time_point p = high_resolution_clock::now();

  milliseconds ms = duration_cast<milliseconds>(p.time_since_epoch());

  seconds s = duration_cast<seconds>(ms);
  std::time_t t = s.count();
  std::size_t fractional_seconds = ms.count() % 1000;

  std::cout << std::ctime(&t) << std::endl;
  std::cout << fractional_seconds << std::endl;
}

example result:

Thu Oct 11 19:10:24 2012

925

Difference between DOM parentNode and parentElement

In Internet Explorer, parentElement is undefined for SVG elements, whereas parentNode is defined.

Checking if a folder exists (and creating folders) in Qt, C++

When you use QDir.mkpath() it returns true if the path already exists, in the other hand QDir.mkdir() returns false if the path already exists. So depending on your program you have to choose which fits better.

You can see more on Qt Documentation

How can I use regex to get all the characters after a specific character, e.g. comma (",")

.+,(.+)

Explanation:

.+,

will search for everything before the comma, including the comma.

(.+) 

will search for everything after the comma, and depending on your regex environment,

\1

is the reference for the first parentheses captured group that you need, in this example, everything after the comma.

data type not understood

Try:

mmatrix = np.zeros((nrows, ncols))

Since the shape parameter has to be an int or sequence of ints

http://docs.scipy.org/doc/numpy/reference/generated/numpy.zeros.html

Otherwise you are passing ncols to np.zeros as the dtype.

What is the string length of a GUID?

22 bytes, if you do it like this:

System.Guid guid = System.Guid.NewGuid();
byte[] guidbytes = guid.ToByteArray();
string uuid = Convert.ToBase64String(guidbytes).Trim('=');

Who is listening on a given TCP port on Mac OS X?

lsof -n -i | awk '{ print $1,$9; }' | sort -u

This displays who's doing what. Remove -n to see hostnames (a bit slower).

Git: can't undo local changes (error: path ... is unmerged)

I find git stash very useful for temporal handling of all 'dirty' states.

Allowing the "Enter" key to press the submit button, as opposed to only using MouseClick

There is a simple trick for this. After you constructed the frame with all it buttons do this:

frame.getRootPane().setDefaultButton(submitButton);

For each frame, you can set a default button that will automatically listen to the Enter key (and maybe some other event's I'm not aware of). When you hit enter in that frame, the ActionListeners their actionPerformed() method will be invoked.


And the problem with your code as far as I see is that your dialog pops up every time you hit a key, because you didn't put it in the if-body. Try changing it to this:

@Override
public void keyPressed(KeyEvent e) {
    if (e.getKeyCode()==KeyEvent.VK_ENTER){
        System.out.println("Hello");

        JOptionPane.showMessageDialog(null , "You've Submitted the name " + nameInput.getText());
    }

}

UPDATE: I found what is wrong with your code. You are adding the key listener to the Submit button instead of to the TextField. Change your code to this:

SubmitButton listener = new SubmitButton(textBoxToEnterName);
textBoxToEnterName.addActionListener(listener);
submit.addKeyListener(listener);

How do you overcome the svn 'out of date' error?

Are you moving it using svn mv, or just mv? I think using just mv may cause this issue.

How to know if an object has an attribute in Python

This is super simple, just use dir(object)
This will return a list of every available function and attribute of the object.

Rounded Corners Image in Flutter

   Container(
      width: 48.0,
      height: 48.0,
      decoration: new BoxDecoration(
        shape: BoxShape.circle,
        image: new DecorationImage(
            fit: BoxFit.fill,
            image: NetworkImage("path to your image")
        )
    )),

How do you say not equal to in Ruby?

Yes. In Ruby the not equal to operator is:

!=

You can get a full list of ruby operators here: https://www.tutorialspoint.com/ruby/ruby_operators.htm.

Python [Errno 98] Address already in use

If you use a TCPServer, UDPServer or their subclasses in the SocketServer module, you can set this class variable (before instanciating a server):

SocketServer.TCPServer.allow_reuse_address = True

(via SocketServer.ThreadingTCPServer - Cannot bind to address after program restart )

This causes the init (constructor) to:

 if self.allow_reuse_address:
     self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

Java: How to stop thread?

One possible way is to do something like this:

public class MyThread extends Thread {
    @Override
    public void run() {
        while (!this.isInterrupted()) {
            //
        }
    }
}

And when you want to stop your thread, just call a method interrupt():

myThread.interrupt();

Of course, this won't stop thread immediately, but in the following iteration of the loop above. In the case of downloading, you need to write a non-blocking code. It means, that you will attempt to read new data from the socket only for a limited amount of time. If there are no data available, it will just continue. It may be done using this method from the class Socket:

mySocket.setSoTimeout(50);

In this case, timeout is set up to 50 ms. After this time has gone and no data was read, it throws an SocketTimeoutException. This way, you may write iterative and non-blocking thread, which may be killed using the construction above.

It's not possible to kill thread in any other way and you've to implement such a behavior yourself. In past, Thread had some method (not sure if kill() or stop()) for this, but it's deprecated now. My experience is, that some implementations of JVM doesn't even contain that method currently.

How to change the Text color of Menu item in Android?

You can set color programmatically.

private static void setMenuTextColor(final Context context, final Toolbar toolbar, final int menuResId, final int colorRes) {
    toolbar.post(new Runnable() {
        @Override
        public void run() {
            View settingsMenuItem =  toolbar.findViewById(menuResId);
            if (settingsMenuItem instanceof TextView) {
                if (DEBUG) {
                    Log.i(TAG, "setMenuTextColor textview");
                }
                TextView tv = (TextView) settingsMenuItem;
                tv.setTextColor(ContextCompat.getColor(context, colorRes));
            } else { // you can ignore this branch, because usually there is not the situation
                Menu menu = toolbar.getMenu();
                MenuItem item = menu.findItem(menuResId);
                SpannableString s = new SpannableString(item.getTitle());
                s.setSpan(new ForegroundColorSpan(ContextCompat.getColor(context, colorRes)), 0, s.length(), 0);
                item.setTitle(s);
            }

        }
    });
}

Session only cookies with Javascript

A simpler solution would be to use sessionStorage, in this case:

var myVariable = "Hello World";

sessionStorage['myvariable'] = myVariable;

var readValue = sessionStorage['myvariable'];
console.log(readValue);

However, keep in mind that sessionStorage saves everything as a string, so when working with arrays / objects, you can use JSON to store them:

var myVariable = {a:[1,2,3,4], b:"some text"};

sessionStorage['myvariable'] = JSON.stringify(myVariable);
var readValue = JSON.parse(sessionStorage['myvariable']);

A page session lasts for as long as the browser is open and survives over page reloads and restores. Opening a page in a new tab or window will cause a new session to be initiated.

So, when you close the page / tab, the data is lost.

Creating stored procedure with declare and set variables

You should try this syntax - assuming you want to have @OrderID as a parameter for your stored procedure:

CREATE PROCEDURE dbo.YourStoredProcNameHere
   @OrderID INT
AS
BEGIN
 DECLARE @OrderItemID AS INT
 DECLARE @AppointmentID AS INT
 DECLARE @PurchaseOrderID AS INT
 DECLARE @PurchaseOrderItemID AS INT
 DECLARE @SalesOrderID AS INT
 DECLARE @SalesOrderItemID AS INT

 SELECT @OrderItemID = OrderItemID 
 FROM [OrderItem] 
 WHERE OrderID = @OrderID

 SELECT @AppointmentID = AppoinmentID 
 FROM [Appointment] 
 WHERE OrderID = @OrderID

 SELECT @PurchaseOrderID = PurchaseOrderID 
 FROM [PurchaseOrder] 
 WHERE OrderID = @OrderID

END

OF course, that only works if you're returning exactly one value (not multiple values!)

jQuery: Setting select list 'selected' based on text, failing strangely

If you want to selected value on drop-down text bases so you should use below changes: Here below is example and country name is dynamic:

    <select id="selectcountry">
    <option value="1">India</option>
    <option value="2">Ireland</option>
    </select>
    <script>
     var country_name ='India'
     $('#selectcountry').find('option:contains("' + country_name + '")').attr('selected', 'selected');
    </script>

How can I center an image in Bootstrap?

Three ways to align img in the center of its parent.

  1. img is an inline element, text-center aligns inline elements in the center of its container should the container be a block element.

_x000D_
_x000D_
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.1/css/bootstrap.css" rel="stylesheet"/>_x000D_
<div class="container mt-5">_x000D_
  <div class="row">_x000D_
    <div class="col text-center">_x000D_
      <img src="https://upload.wikimedia.org/wikipedia/en/8/80/Wikipedia-logo-v2.svg" alt="" class="img-fluid">_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

  1. mx-auto centers block elements. In order to so, change display of the img from inline to block with d-block class.

_x000D_
_x000D_
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.1/css/bootstrap.css" rel="stylesheet"/>_x000D_
<div class="container mt-5">_x000D_
  <div class="row">_x000D_
    <div class="col">_x000D_
      <img src="https://upload.wikimedia.org/wikipedia/en/8/80/Wikipedia-logo-v2.svg" alt="" class="img-fluid d-block mx-auto">_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

  1. Use d-flex and justify-content-center on its parent.

_x000D_
_x000D_
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.1/css/bootstrap.css" rel="stylesheet"/>_x000D_
<div class="container mt-5">_x000D_
  <div class="row">_x000D_
    <div class="col d-flex justify-content-center">_x000D_
      <img src="https://upload.wikimedia.org/wikipedia/en/8/80/Wikipedia-logo-v2.svg" alt="" class="img-fluid">_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

What is best tool to compare two SQL Server databases (schema and data)?

Database Workbench can made it too

http://www.upscene.com/products.dbw.index.php

Cross database development

Use the Schema Compare and Migration Tools to compare testing and deployed databases, migrate existing databases to different database systems.

you can also made it with database Comparer

http://www.clevercomponents.com/products/dbcomparer/dbcomparer.asp

I use it for Firebird and it works well.

How to solve could not create the virtual machine error of Java Virtual Machine Launcher?

I was facing the same issue while i was using "jdk-10.0.1_windows-x64_bin" and eclipse-jee-oxygen-3a-win32-x86_64 on Windows 64 bit Operating System.

But Finally i resolved this issue by changing my jdk to "jdk-8u172-windows-x64", Now its working fine. @Thanks

How to import keras from tf.keras in Tensorflow?

Try from tensorflow.python import keras

with this, you can easily change keras dependent code to tensorflow in one line change.

You can also try from tensorflow.contrib import keras. This works on tensorflow 1.3

Edited: for tensorflow 1.10 and above you can use import tensorflow.keras as keras to get keras in tensorflow.

Powershell 2 copy-item which creates a folder if doesn't exist

Yes, add the -Force parameter.

copy-item $from $to -Recurse -Force

Change image in HTML page every few seconds

As of current edited version of the post, you call setInterval at each change's end, adding a new "changer" with each new iterration. That means after first run, there's one of them ticking in memory, after 100 runs, 100 different changers change image 100 times every second, completely destroying performance and producing confusing results.

You only need to "prime" setInterval once. Remove it from function and place it inside onload instead of direct function call.

Getting list of parameter names inside python function

import inspect

def func(a,b,c=5):
    pass

inspect.getargspec(func)  # inspect.signature(func) in Python 3

(['a', 'b', 'c'], None, None, (5,))

Show Image View from file path?

String path = Environment.getExternalStorageDirectory()+ "/Images/test.jpg";

File imgFile = new File(path);
if(imgFile.exists())
{
   Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());
   ImageView imageView=(ImageView)findViewById(R.id.imageView);
  imageView.setImageBitmap(myBitmap);
}

Create SQLite Database and table

The next link will bring you to a great tutorial, that helped me a lot!

How to SQLITE in C#

I nearly used everything in that article to create the SQLite database for my own C# Application.

Don't forget to download the SQLite.dll, and add it as a reference to your project. This can be done using NuGet and by adding the dll manually.

After you added the reference, refer to the dll from your code using the following line on top of your class:

using System.Data.SQLite;

You can find the dll's here:

SQLite DLL's

You can find the NuGet way here:

NuGet

Up next is the create script. Creating a database file:

SQLiteConnection.CreateFile("MyDatabase.sqlite");

SQLiteConnection m_dbConnection = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");
m_dbConnection.Open();

string sql = "create table highscores (name varchar(20), score int)";

SQLiteCommand command = new SQLiteCommand(sql, m_dbConnection);
command.ExecuteNonQuery();

sql = "insert into highscores (name, score) values ('Me', 9001)";

command = new SQLiteCommand(sql, m_dbConnection);
command.ExecuteNonQuery();

m_dbConnection.Close();

After you created a create script in C#, I think you might want to add rollback transactions, it is safer and it will keep your database from failing, because the data will be committed at the end in one big piece as an atomic operation to the database and not in little pieces, where it could fail at 5th of 10 queries for example.

Example on how to use transactions:

 using (TransactionScope tran = new TransactionScope())
 {
     //Insert create script here.

     //Indicates that creating the SQLiteDatabase went succesfully, so the database can be committed.
     tran.Complete();
 }

Python 2,3 Convert Integer to "bytes" Cleanly

Answer 1:

To convert a string to a sequence of bytes in either Python 2 or Python 3, you use the string's encode method. If you don't supply an encoding parameter 'ascii' is used, which will always be good enough for numeric digits.

s = str(n).encode()

In Python 2 str(n) already produces bytes; the encode will do a double conversion as this string is implicitly converted to Unicode and back again to bytes. It's unnecessary work, but it's harmless and is completely compatible with Python 3.


Answer 2:

Above is the answer to the question that was actually asked, which was to produce a string of ASCII bytes in human-readable form. But since people keep coming here trying to get the answer to a different question, I'll answer that question too. If you want to convert 10 to b'10' use the answer above, but if you want to convert 10 to b'\x0a\x00\x00\x00' then keep reading.

The struct module was specifically provided for converting between various types and their binary representation as a sequence of bytes. The conversion from a type to bytes is done with struct.pack. There's a format parameter fmt that determines which conversion it should perform. For a 4-byte integer, that would be i for signed numbers or I for unsigned numbers. For more possibilities see the format character table, and see the byte order, size, and alignment table for options when the output is more than a single byte.

import struct
s = struct.pack('<i', 5) # b'\x05\x00\x00\x00'

Check for internet connection with Swift

Swift 5

import SystemConfiguration    

protocol Utilities {}
extension NSObject: Utilities {
    enum ReachabilityStatus {
        case notReachable
        case reachableViaWWAN
        case reachableViaWiFi
    }
    
    var currentReachabilityStatus: ReachabilityStatus {
        
        var zeroAddress = sockaddr_in()
        zeroAddress.sin_len = UInt8(MemoryLayout<sockaddr_in>.size)
        zeroAddress.sin_family = sa_family_t(AF_INET)
        guard let defaultRouteReachability = withUnsafePointer(to: &zeroAddress, {
            $0.withMemoryRebound(to: sockaddr.self, capacity: 1) {
                SCNetworkReachabilityCreateWithAddress(nil, $0)
            }
        }) else {
            return .notReachable
        }
        
        var flags: SCNetworkReachabilityFlags = []
        if !SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags) {
            return .notReachable
        }
        
        if flags.contains(.reachable) == false {
            // The target host is not reachable.
            return .notReachable
        }
        else if flags.contains(.isWWAN) == true {
            // WWAN connections are OK if the calling application is using the CFNetwork APIs.
            return .reachableViaWWAN
        }
        else if flags.contains(.connectionRequired) == false {
            // If the target host is reachable and no connection is required then we'll assume that you're on Wi-Fi...
            return .reachableViaWiFi
        }
        else if (flags.contains(.connectionOnDemand) == true || flags.contains(.connectionOnTraffic) == true) && flags.contains(.interventionRequired) == false {
            // The connection is on-demand (or on-traffic) if the calling application is using the CFSocketStream or higher APIs and no [user] intervention is needed
            return .reachableViaWiFi
        }
        else {
            return .notReachable
        }
    }
}

In any method use the below condition

if currentReachabilityStatus == .notReachable {
    // Network Unavailable
} else {
    // Network Available
}

Why Choose Struct Over Class?

Since struct instances are allocated on stack, and class instances are allocated on heap, structs can sometimes be drastically faster.

However, you should always measure it yourself and decide based on your unique use case.

Consider the following example, which demonstrates 2 strategies of wrapping Int data type using struct and class. I am using 10 repeated values are to better reflect real world, where you have multiple fields.

class Int10Class {
    let value1, value2, value3, value4, value5, value6, value7, value8, value9, value10: Int
    init(_ val: Int) {
        self.value1 = val
        self.value2 = val
        self.value3 = val
        self.value4 = val
        self.value5 = val
        self.value6 = val
        self.value7 = val
        self.value8 = val
        self.value9 = val
        self.value10 = val
    }
}

struct Int10Struct {
    let value1, value2, value3, value4, value5, value6, value7, value8, value9, value10: Int
    init(_ val: Int) {
        self.value1 = val
        self.value2 = val
        self.value3 = val
        self.value4 = val
        self.value5 = val
        self.value6 = val
        self.value7 = val
        self.value8 = val
        self.value9 = val
        self.value10 = val
    }
}

func + (x: Int10Class, y: Int10Class) -> Int10Class {
    return IntClass(x.value + y.value)
}

func + (x: Int10Struct, y: Int10Struct) -> Int10Struct {
    return IntStruct(x.value + y.value)
}

Performance is measured using

// Measure Int10Class
measure("class (10 fields)") {
    var x = Int10Class(0)
    for _ in 1...10000000 {
        x = x + Int10Class(1)
    }
}

// Measure Int10Struct
measure("struct (10 fields)") {
    var y = Int10Struct(0)
    for _ in 1...10000000 {
        y = y + Int10Struct(1)
    }
}

func measure(name: String, @noescape block: () -> ()) {
    let t0 = CACurrentMediaTime()

    block()

    let dt = CACurrentMediaTime() - t0
    print("\(name) -> \(dt)")
}

Code can be found at https://github.com/knguyen2708/StructVsClassPerformance

UPDATE (27 Mar 2018):

As of Swift 4.0, Xcode 9.2, running Release build on iPhone 6S, iOS 11.2.6, Swift Compiler setting is -O -whole-module-optimization:

  • class version took 2.06 seconds
  • struct version took 4.17e-08 seconds (50,000,000 times faster)

(I no longer average multiple runs, as variances are very small, under 5%)

Note: the difference is a lot less dramatic without whole module optimization. I'd be glad if someone can point out what the flag actually does.


UPDATE (7 May 2016):

As of Swift 2.2.1, Xcode 7.3, running Release build on iPhone 6S, iOS 9.3.1, averaged over 5 runs, Swift Compiler setting is -O -whole-module-optimization:

  • class version took 2.159942142s
  • struct version took 5.83E-08s (37,000,000 times faster)

Note: as someone mentioned that in real-world scenarios, there will be likely more than 1 field in a struct, I have added tests for structs/classes with 10 fields instead of 1. Surprisingly, results don't vary much.


ORIGINAL RESULTS (1 June 2014):

(Ran on struct/class with 1 field, not 10)

As of Swift 1.2, Xcode 6.3.2, running Release build on iPhone 5S, iOS 8.3, averaged over 5 runs

  • class version took 9.788332333s
  • struct version took 0.010532942s (900 times faster)

OLD RESULTS (from unknown time)

(Ran on struct/class with 1 field, not 10)

With release build on my MacBook Pro:

  • The class version took 1.10082 sec
  • The struct version took 0.02324 sec (50 times faster)

MVC pattern on Android

Android's MVC pattern is (kind-of) implemented with their Adapter classes. They replace a controller with an "adapter." The description for the adapter states:

An Adapter object acts as a bridge between an AdapterView and the underlying data for that view.

I'm just looking into this for an Android application that reads from a database, so I don't know how well it works yet. However, it seems a little like Qt's Model-View-Delegate architecture, which they claim is a step up from a traditional MVC pattern. At least on the PC, Qt's pattern works fairly well.

Can you install and run apps built on the .NET framework on a Mac?

You can use a .Net environment Visual studio, Take a look at the differences with the PC version.

A lighter editor would be Visual Code

Alternatives :

  1. Installing the Mono Project runtime . It allows you to re-compile the code and run it on a Mac, but this requires various alterations to the codebase, as the fuller .Net Framework is not available. (Also, WPF applications aren't supported here either.)

  2. Virtual machine (VMWare Fusion perhaps)

  3. Update your codebase to .Net Core, (before choosing this option take a look at this migration process)

    • .Net Core 3.1 is an open-source, free and available on Window, MacOs and Linux

    • As of September 14, a release candidate 1 of .Net Core 5.0 has been deployed on Window, MacOs and Linux.

[1] : Release candidate (RC) : releases providing early access to complete features. These releases are supported for production use when they have a go-live license

What is TypeScript and why would I use it in place of JavaScript?

"TypeScript Fundamentals" -- a Pluralsight video-course by Dan Wahlin and John Papa is a really good, presently (March 25, 2016) updated to reflect TypeScript 1.8, introduction to Typescript.

For me the really good features, beside the nice possibilities for intellisense, are the classes, interfaces, modules, the ease of implementing AMD, and the possibility to use the Visual Studio Typescript debugger when invoked with IE.

To summarize: If used as intended, Typescript can make JavaScript programming more reliable, and easier. It can increase the productivity of the JavaScript programmer significantly over the full SDLC.

How do I add a reference to the MySQL connector for .NET?

This is an older question, but I found it yesterday while struggling with getting the MySQL Connector reference working properly on examples I'd found on the web. I'm working with VS 2010 on Win7 64 bit but have to work with .NET 3.5.

As others have stated, you need to download the .Net & Mono versions (I don't know why this is true, but it's what I've found works). The link to the connectors is given above in the earlier answers.

  • Extract the connectors somewhere convenient.
  • Open the project in Visual Studio, then on the menu bar navigate to Solution Explorer (View > Solution Explorer), and choose Properties (first box on the far left of the toolbar. The Solution Explorer shows up in the top right pane for me, but YMMV).
  • In Properties, select References & locate the instance for mysql.data. It's likely to have a yellow bang on it (Yellow triangle with exclamation point in it). Remove it.
  • Then on the menu bar, navigate to Project > Add Reference... > Browse > point to where you downloaded the connectors. I have only been able to get the V2 version to work, but that may be a factor of my platform, not sure.
  • Clean & build your application. You should now be able to use the MySQL connectors to talk to your database.
  • You can also now downgrade your .NET instance if you need to (we're constrained to .NET 3.5, but mysql.data.dll wants 4.0 at the time of my writing this). On the menu bar, navigate to the properties of your project (Project > Properties). Choose the Application tab > Target framework > Choose which .NET framework you want to use. You have to build the application at least once before you can change the .NET framework. Once you built once the connector will no longer complain about the lower version of .NET.

javax.websocket client simple example

TooTallNate has a simple client side https://github.com/TooTallNate/Java-WebSocket

Just add the java_websocket.jar in the dist folder into your project.

 import org.java_websocket.client.WebSocketClient;
 import org.java_websocket.drafts.Draft_10;
 import org.java_websocket.handshake.ServerHandshake;
 import org.json.JSONException;
 import org.json.JSONObject;

  WebSocketClient mWs = new WebSocketClient( new URI( "ws://socket.example.com:1234" ), new Draft_10() )
{
                    @Override
                    public void onMessage( String message ) {
                     JSONObject obj = new JSONObject(message);
                     String channel = obj.getString("channel");
                    }

                    @Override
                    public void onOpen( ServerHandshake handshake ) {
                        System.out.println( "opened connection" );
                    }

                    @Override
                    public void onClose( int code, String reason, boolean remote ) {
                        System.out.println( "closed connection" );
                    }

                    @Override
                    public void onError( Exception ex ) {
                        ex.printStackTrace();
                    }

                };
 //open websocket
 mWs.connect();
 JSONObject obj = new JSONObject();
 obj.put("event", "addChannel");
 obj.put("channel", "ok_btccny_ticker");
 String message = obj.toString();
 //send message
 mWs.send(message);

// and to close websocket

 mWs.close();

How to resize the jQuery DatePicker control

with out changing the css file you can also change the calendar size  by putting the the following code in to ur <head>.....</head> tag:


<head>
<meta charset="utf-8" />
<title>jQuery UI Datepicker - Icon trigger</title>
<link rel="stylesheet" href="http://code.jquery.com/ui/1.10.2/themes/smoothness/jquery-ui.css" />
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script src="http://code.jquery.com/ui/1.10.2/jquery-ui.js"></script>
<link rel="stylesheet" href="/resources/demos/style.css" />
<style type="text/css">
.ui-widget { font-family: Lucida Grande, Lucida Sans, Arial, sans-serif; font-size: 0.6em; }
</style>

<script>



$(function() {

$( "#datepicker" ).datepicker({
//font-size:10px;
 //numberOfMonths: 3,

showButtonPanel: true,
showOn: 'button',
buttonImage: "images/calendar1.gif",
buttonImageOnly: true
});
});
</script>

</head>

What is The Rule of Three?

Introduction

C++ treats variables of user-defined types with value semantics. This means that objects are implicitly copied in various contexts, and we should understand what "copying an object" actually means.

Let us consider a simple example:

class person
{
    std::string name;
    int age;

public:

    person(const std::string& name, int age) : name(name), age(age)
    {
    }
};

int main()
{
    person a("Bjarne Stroustrup", 60);
    person b(a);   // What happens here?
    b = a;         // And here?
}

(If you are puzzled by the name(name), age(age) part, this is called a member initializer list.)

Special member functions

What does it mean to copy a person object? The main function shows two distinct copying scenarios. The initialization person b(a); is performed by the copy constructor. Its job is to construct a fresh object based on the state of an existing object. The assignment b = a is performed by the copy assignment operator. Its job is generally a little more complicated, because the target object is already in some valid state that needs to be dealt with.

Since we declared neither the copy constructor nor the assignment operator (nor the destructor) ourselves, these are implicitly defined for us. Quote from the standard:

The [...] copy constructor and copy assignment operator, [...] and destructor are special member functions. [ Note: The implementation will implicitly declare these member functions for some class types when the program does not explicitly declare them. The implementation will implicitly define them if they are used. [...] end note ] [n3126.pdf section 12 §1]

By default, copying an object means copying its members:

The implicitly-defined copy constructor for a non-union class X performs a memberwise copy of its subobjects. [n3126.pdf section 12.8 §16]

The implicitly-defined copy assignment operator for a non-union class X performs memberwise copy assignment of its subobjects. [n3126.pdf section 12.8 §30]

Implicit definitions

The implicitly-defined special member functions for person look like this:

// 1. copy constructor
person(const person& that) : name(that.name), age(that.age)
{
}

// 2. copy assignment operator
person& operator=(const person& that)
{
    name = that.name;
    age = that.age;
    return *this;
}

// 3. destructor
~person()
{
}

Memberwise copying is exactly what we want in this case: name and age are copied, so we get a self-contained, independent person object. The implicitly-defined destructor is always empty. This is also fine in this case since we did not acquire any resources in the constructor. The members' destructors are implicitly called after the person destructor is finished:

After executing the body of the destructor and destroying any automatic objects allocated within the body, a destructor for class X calls the destructors for X's direct [...] members [n3126.pdf 12.4 §6]

Managing resources

So when should we declare those special member functions explicitly? When our class manages a resource, that is, when an object of the class is responsible for that resource. That usually means the resource is acquired in the constructor (or passed into the constructor) and released in the destructor.

Let us go back in time to pre-standard C++. There was no such thing as std::string, and programmers were in love with pointers. The person class might have looked like this:

class person
{
    char* name;
    int age;

public:

    // the constructor acquires a resource:
    // in this case, dynamic memory obtained via new[]
    person(const char* the_name, int the_age)
    {
        name = new char[strlen(the_name) + 1];
        strcpy(name, the_name);
        age = the_age;
    }

    // the destructor must release this resource via delete[]
    ~person()
    {
        delete[] name;
    }
};

Even today, people still write classes in this style and get into trouble: "I pushed a person into a vector and now I get crazy memory errors!" Remember that by default, copying an object means copying its members, but copying the name member merely copies a pointer, not the character array it points to! This has several unpleasant effects:

  1. Changes via a can be observed via b.
  2. Once b is destroyed, a.name is a dangling pointer.
  3. If a is destroyed, deleting the dangling pointer yields undefined behavior.
  4. Since the assignment does not take into account what name pointed to before the assignment, sooner or later you will get memory leaks all over the place.

Explicit definitions

Since memberwise copying does not have the desired effect, we must define the copy constructor and the copy assignment operator explicitly to make deep copies of the character array:

// 1. copy constructor
person(const person& that)
{
    name = new char[strlen(that.name) + 1];
    strcpy(name, that.name);
    age = that.age;
}

// 2. copy assignment operator
person& operator=(const person& that)
{
    if (this != &that)
    {
        delete[] name;
        // This is a dangerous point in the flow of execution!
        // We have temporarily invalidated the class invariants,
        // and the next statement might throw an exception,
        // leaving the object in an invalid state :(
        name = new char[strlen(that.name) + 1];
        strcpy(name, that.name);
        age = that.age;
    }
    return *this;
}

Note the difference between initialization and assignment: we must tear down the old state before assigning to name to prevent memory leaks. Also, we have to protect against self-assignment of the form x = x. Without that check, delete[] name would delete the array containing the source string, because when you write x = x, both this->name and that.name contain the same pointer.

Exception safety

Unfortunately, this solution will fail if new char[...] throws an exception due to memory exhaustion. One possible solution is to introduce a local variable and reorder the statements:

// 2. copy assignment operator
person& operator=(const person& that)
{
    char* local_name = new char[strlen(that.name) + 1];
    // If the above statement throws,
    // the object is still in the same state as before.
    // None of the following statements will throw an exception :)
    strcpy(local_name, that.name);
    delete[] name;
    name = local_name;
    age = that.age;
    return *this;
}

This also takes care of self-assignment without an explicit check. An even more robust solution to this problem is the copy-and-swap idiom, but I will not go into the details of exception safety here. I only mentioned exceptions to make the following point: Writing classes that manage resources is hard.

Noncopyable resources

Some resources cannot or should not be copied, such as file handles or mutexes. In that case, simply declare the copy constructor and copy assignment operator as private without giving a definition:

private:

    person(const person& that);
    person& operator=(const person& that);

Alternatively, you can inherit from boost::noncopyable or declare them as deleted (in C++11 and above):

person(const person& that) = delete;
person& operator=(const person& that) = delete;

The rule of three

Sometimes you need to implement a class that manages a resource. (Never manage multiple resources in a single class, this will only lead to pain.) In that case, remember the rule of three:

If you need to explicitly declare either the destructor, copy constructor or copy assignment operator yourself, you probably need to explicitly declare all three of them.

(Unfortunately, this "rule" is not enforced by the C++ standard or any compiler I am aware of.)

The rule of five

From C++11 on, an object has 2 extra special member functions: the move constructor and move assignment. The rule of five states to implement these functions as well.

An example with the signatures:

class person
{
    std::string name;
    int age;

public:
    person(const std::string& name, int age);        // Ctor
    person(const person &) = default;                // 1/5: Copy Ctor
    person(person &&) noexcept = default;            // 4/5: Move Ctor
    person& operator=(const person &) = default;     // 2/5: Copy Assignment
    person& operator=(person &&) noexcept = default; // 5/5: Move Assignment
    ~person() noexcept = default;                    // 3/5: Dtor
};

The rule of zero

The rule of 3/5 is also referred to as the rule of 0/3/5. The zero part of the rule states that you are allowed to not write any of the special member functions when creating your class.

Advice

Most of the time, you do not need to manage a resource yourself, because an existing class such as std::string already does it for you. Just compare the simple code using a std::string member to the convoluted and error-prone alternative using a char* and you should be convinced. As long as you stay away from raw pointer members, the rule of three is unlikely to concern your own code.

iOS change navigation bar title font and color

Add this extension

extension UINavigationBar {
    func changeFont() {
        self.titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white, NSAttributedStringKey.font: UIFont(name:"Poppins-Medium", size: 17)!]
    }
}

Add the following line in viewDidLoad()

self.navigationController?.navigationBar.changeFont()

Should I learn C before learning C++?

There is no need to learn C before learning C++.

They are different languages. It is a common misconception that C++ is in some way dependent on C and not a fully specified language on its own.

Just because C++ shares a lot of the same syntax and a lot of the same semantics, does not mean you need to learn C first.

If you learn C++ you will eventually learn most of C with some differences between the languages that you will learn over time. In fact its a very hard thing to write proper C++ because intermediate C++ programmers tend to write C/C++.That is true whether or not you started with C or started with C++.

If you know C first, then that is good plus to learning C++. You will start with knowing a chunk of the language. If you do not know C first then there is no point focusing on a different language. There are plenty of good books and tutorials available that start you from knowing nothing and will cover anything you would learn from C which applies to C++ as well.

Please see further reasoning in this answer.

Get key and value of object in JavaScript?

for (var i in a) {
   console.log(a[i],i)
}

ASP.NET MVC JsonResult Date Format

Override the controllers Json/JsonResult to return JSON.Net:

This works a treat

Vue 'export default' vs 'new Vue'

Whenever you use

export someobject

and someobject is

{
 "prop1":"Property1",
 "prop2":"Property2",
}

the above you can import anywhere using import or module.js and there you can use someobject. This is not a restriction that someobject will be an object only it can be a function too, a class or an object.

When you say

new Object()

like you said

new Vue({
  el: '#app',
  data: []
)}

Here you are initiating an object of class Vue.

I hope my answer explains your query in general and more explicitly.

Show Hide div if, if statement is true

from php you can invoke jquery like this but my 2nd method is much cleaner and better for php

if($switchView) :?>
 <script>$('.container').hide();</script>
 <script>$('.confirm').show();</script>
<?php endif;

another way is to initiate your class and dynamically invoke the condition like this

$registerForm ='block'; 

then in your html use this

<div class="col" style="display: <?= $registerForm?>">

now you can play with the view with if and else easily without having a messed code example

if($condition)  registerForm = 'none'; 

Make sure you use 'block' to show and 'none' to hide. This is far the easiest way with php

Order a List (C#) by many fields?

Make your object something like

public class MyObject : IComparable
{
    public string a;
    public string b;

    virtual public int CompareTo(object obj)
    {
        if (obj is MyObject)
        {
            var compareObj = (MyObject)obj;
            if (this.a.CompareTo(compareObj.a) == 0)
            {
                // compare second value
                return this.b.CompareTo(compareObj.b);
            }
            return this.a.CompareTo(compareObj.b);
        }
        else
        {
            throw new ArgumentException("Object is not a MyObject ");
        }
    }
}

also note that the returns for CompareTo :

http://msdn.microsoft.com/en-us/library/system.icomparable.compareto.aspx

Then, if you have a List of MyObject, call .Sort() ie

var objList = new List<MyObject>();
objList.Sort();

creating batch script to unzip a file without additional zip tools

If you have PowerShell 5.0 or higher (pre-installed with Windows 10 and Windows Server 2016):

powershell Expand-Archive your.zip -DestinationPath your_destination

bash "if [ false ];" returns true instead of false -- why?

I found that I can do some basic logic by running something like:

A=true
B=true
if ($A && $B); then
    C=true
else
    C=false
fi
echo $C

List files with certain extensions with ls and grep

In case you are still looking for an alternate solution:

ls | grep -i -e '\\.tcl$' -e '\\.exe$' -e '\\.mp4$'

Feel free to add more -e flags if needed.

Changing project port number in Visual Studio 2013

Steps to resolve this:

  1. Open the solution file.
  2. Find the Port tag against your project name.
  3. Assign any different port as current.
  4. Right click on your project and select Property Pages.
  5. Click on Start Options tab and checked Start URL: option.
  6. Assign the start URL in front of Start URL option like:
    localhost:8080/login.aspx

java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare();

Android basically works on two thread types namely UI thread and background thread. According to android documentation -

Do not access the Android UI toolkit from outside the UI thread to fix this problem, Android offers several ways to access the UI thread from other threads. Here is a list of methods that can help:

Activity.runOnUiThread(Runnable)  
View.post(Runnable)  
View.postDelayed(Runnable, long)

Now there are various methods to solve this problem. I will explain it by code sample

runOnUiThread

new Thread()
{
    public void run()
    {
        myactivity.this.runOnUiThread(new runnable()
        {
            public void run()
            {
                //Do your UI operations like dialog opening or Toast here
            }
        });
    }
}.start();

LOOPER

Class used to run a message loop for a thread. Threads by default do not have a message loop associated with them; to create one, call prepare() in the thread that is to run the loop, and then loop() to have it process messages until the loop is stopped.

class LooperThread extends Thread {
    public Handler mHandler;

    public void run() {
        Looper.prepare();

        mHandler = new Handler() {
            public void handleMessage(Message msg) {
                // process incoming messages here
            }
        };

        Looper.loop();
    }

AsyncTask

AsyncTask allows you to perform asynchronous work on your user interface. It performs the blocking operations in a worker thread and then publishes the results on the UI thread, without requiring you to handle threads and/or handlers yourself.

public void onClick(View v) {
    new CustomTask().execute((Void[])null);
}


private class CustomTask extends AsyncTask<Void, Void, Void> {

    protected Void doInBackground(Void... param) {
        //Do some work
        return null;
    }

    protected void onPostExecute(Void param) {
        //Print Toast or open dialog
    }
}

Handler

A Handler allows you to send and process Message and Runnable objects associated with a thread's MessageQueue.

Message msg = new Message();


    new Thread()
    {
        public void run()
        {
            msg.arg1=1;
            handler.sendMessage(msg);
        }
    }.start();



    Handler handler = new Handler(new Handler.Callback() {

        @Override
        public boolean handleMessage(Message msg) {
            if(msg.arg1==1)
            {
                //Print Toast or open dialog        
            }
            return false;
        }
    });

How to read and write to a text file in C++?

Default c++ mechanism for file IO is called streams. Streams can be of three flavors: input, output and inputoutput. Input streams act like sources of data. To read data from an input stream you use >> operator:

istream >> my_variable; //This code will read a value from stream into your variable.

Operator >> acts different for different types. If in the example above my_variable was an int, then a number will be read from the strem, if my_variable was a string, then a word would be read, etc. You can read more then one value from the stream by writing istream >> a >> b >> c; where a, b and c would be your variables.

Output streams act like sink to which you can write your data. To write your data to a stream, use << operator.

ostream << my_variable; //This code will write a value from your variable into stream.

As with input streams, you can write several values to the stream by writing something like this:

ostream << a << b << c;

Obviously inputoutput streams can act as both.

In your code sample you use cout and cin stream objects. cout stands for console-output and cin for console-input. Those are predefined streams for interacting with default console.

To interact with files, you need to use ifstream and ofstream types. Similar to cin and cout, ifstream stands for input-file-stream and ofstream stands for output-file-stream.

Your code might look like this:

#include <iostream>
#include <fstream>

using namespace std;

int start()
{
    cout << "Welcome...";

    // do fancy stuff

    return 0;
}

int main ()
{
    string usreq, usr, yn, usrenter;

    cout << "Is this your first time using TEST" << endl;
    cin >> yn;
    if (yn == "y")
    {
        ifstream iusrfile;
        ofstream ousrfile;
        iusrfile.open("usrfile.txt");
        iusrfile >> usr;
        cout << iusrfile; // I'm not sure what are you trying to do here, perhaps print iusrfile contents?
        iusrfile.close();
        cout << "Please type your Username. \n";
        cin >> usrenter;
        if (usrenter == usr)
        {
            start ();
        }
    }
    else
    {
        cout << "THAT IS NOT A REGISTERED USERNAME.";
    }

    return 0;
}

For further reading you might want to look at c++ I/O reference

Append a Lists Contents to another List C#

if you want to get "terse" :)

List<string>GlobalStrings = new List<string>(); 

for(int x=1; x<10; x++) GlobalStrings.AddRange(new List<string> { "some value", "another value"});

How to replace part of string by position?

As an extension method.

public static class StringBuilderExtension
{
    public static string SubsituteString(this string OriginalStr, int index, int length, string SubsituteStr)
    {
        return new StringBuilder(OriginalStr).Remove(index, length).Insert(index, SubsituteStr).ToString();
    }
}