Programs & Examples On #Jbuilder

JBuilder is a IDE for Java developed by Embarcadero Technologies. It is also the name of a Ruby library for producing JSON.

Bundler::GemNotFound: Could not find rake-10.3.2 in any of the sources

bundle install --path vendor/cache

generally fixes it as that is the more common problem. Basically, your bundler path configuration is messed up. See their documentation (first paragraph) for where to find those configurations and change them manually if needed.

What's the difference between interface and @interface in java?

The interface keyword indicates that you are declaring a traditional interface class in Java.
The @interface keyword is used to declare a new annotation type.

See docs.oracle tutorial on annotations for a description of the syntax.
See the JLS if you really want to get into the details of what @interface means.

LDAP Authentication using Java

This is my LDAP Java login test application supporting LDAP:// and LDAPS:// self-signed test certificate. Code is taken from few SO posts, simplified implementation and removed legacy sun.java.* imports.

Usage
I have run this in Windows7 and Linux machines against WinAD directory service. Application prints username and member groups.

$ java -cp classes test.LoginLDAP url=ldap://1.2.3.4:389 [email protected] password=mypwd

$ java -cp classes test.LoginLDAP url=ldaps://1.2.3.4:636 [email protected] password=mypwd

Test application supports temporary self-signed test certificates for ldaps:// protocol, this DummySSLFactory accepts any server cert so man-in-the-middle is possible. Real life installation should import server certificate to a local JKS keystore file and not using dummy factory.

Application uses enduser's username+password for initial context and ldap queries, it works for WinAD but don't know if can be used for all ldap server implementations. You could create context with internal username+pwd then run queries to see if given enduser is found.

LoginLDAP.java

package test;

import java.util.*;
import javax.naming.*;
import javax.naming.directory.*;

public class LoginLDAP {

    public static void main(String[] args) throws Exception {
        Map<String,String> params = createParams(args);

        String url = params.get("url"); // ldap://1.2.3.4:389 or ldaps://1.2.3.4:636
        String principalName = params.get("username"); // [email protected]
        String domainName = params.get("domain"); // mydomain.com or empty

        if (domainName==null || "".equals(domainName)) {
            int delim = principalName.indexOf('@');
            domainName = principalName.substring(delim+1);
        }

        Properties props = new Properties();
        props.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
        props.put(Context.PROVIDER_URL, url); 
        props.put(Context.SECURITY_PRINCIPAL, principalName); 
        props.put(Context.SECURITY_CREDENTIALS, params.get("password")); // secretpwd
        if (url.toUpperCase().startsWith("LDAPS://")) {
            props.put(Context.SECURITY_PROTOCOL, "ssl");
            props.put(Context.SECURITY_AUTHENTICATION, "simple");
            props.put("java.naming.ldap.factory.socket", "test.DummySSLSocketFactory");         
        }

        InitialDirContext context = new InitialDirContext(props);
        try {
            SearchControls ctrls = new SearchControls();
            ctrls.setSearchScope(SearchControls.SUBTREE_SCOPE);
            NamingEnumeration<SearchResult> results = context.search(toDC(domainName),"(& (userPrincipalName="+principalName+")(objectClass=user))", ctrls);
            if(!results.hasMore())
                throw new AuthenticationException("Principal name not found");

            SearchResult result = results.next();
            System.out.println("distinguisedName: " + result.getNameInNamespace() ); // CN=Firstname Lastname,OU=Mycity,DC=mydomain,DC=com

            Attribute memberOf = result.getAttributes().get("memberOf");
            if(memberOf!=null) {
                for(int idx=0; idx<memberOf.size(); idx++) {
                    System.out.println("memberOf: " + memberOf.get(idx).toString() ); // CN=Mygroup,CN=Users,DC=mydomain,DC=com
                    //Attribute att = context.getAttributes(memberOf.get(idx).toString(), new String[]{"CN"}).get("CN");
                    //System.out.println( att.get().toString() ); //  CN part of groupname
                }
            }
        } finally {
            try { context.close(); } catch(Exception ex) { }
        }       
    }

    /**
     * Create "DC=sub,DC=mydomain,DC=com" string
     * @param domainName    sub.mydomain.com
     * @return
     */
    private static String toDC(String domainName) {
        StringBuilder buf = new StringBuilder();
        for (String token : domainName.split("\\.")) {
            if(token.length()==0) continue;
            if(buf.length()>0)  buf.append(",");
            buf.append("DC=").append(token);
        }
        return buf.toString();
    }

    private static Map<String,String> createParams(String[] args) {
        Map<String,String> params = new HashMap<String,String>();  
        for(String str : args) {
            int delim = str.indexOf('=');
            if (delim>0) params.put(str.substring(0, delim).trim(), str.substring(delim+1).trim());
            else if (delim==0) params.put("", str.substring(1).trim());
            else params.put(str, null);
        }
        return params;
    }

}

And SSL helper class.

package test;

import java.io.*;
import java.net.*;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;    
import javax.net.*;
import javax.net.ssl.*;

public class DummySSLSocketFactory extends SSLSocketFactory {
    private SSLSocketFactory socketFactory;
    public DummySSLSocketFactory() {
        try {
          SSLContext ctx = SSLContext.getInstance("TLS");
          ctx.init(null, new TrustManager[]{ new DummyTrustManager()}, new SecureRandom());
          socketFactory = ctx.getSocketFactory();
        } catch ( Exception ex ){ throw new IllegalArgumentException(ex); }
    }

      public static SocketFactory getDefault() { return new DummySSLSocketFactory(); }

      @Override public String[] getDefaultCipherSuites() { return socketFactory.getDefaultCipherSuites(); }
      @Override public String[] getSupportedCipherSuites() { return socketFactory.getSupportedCipherSuites(); }

      @Override public Socket createSocket(Socket socket, String string, int i, boolean bln) throws IOException {
        return socketFactory.createSocket(socket, string, i, bln);
      }
      @Override public Socket createSocket(String string, int i) throws IOException, UnknownHostException {
        return socketFactory.createSocket(string, i);
      }
      @Override public Socket createSocket(String string, int i, InetAddress ia, int i1) throws IOException, UnknownHostException {
        return socketFactory.createSocket(string, i, ia, i1);
      }
      @Override public Socket createSocket(InetAddress ia, int i) throws IOException {
        return socketFactory.createSocket(ia, i);
      }
      @Override public Socket createSocket(InetAddress ia, int i, InetAddress ia1, int i1) throws IOException {
        return socketFactory.createSocket(ia, i, ia1, i1);
      }
}

class DummyTrustManager implements X509TrustManager {
    @Override public void checkClientTrusted(X509Certificate[] xcs, String str) {
        // do nothing
    }
    @Override public void checkServerTrusted(X509Certificate[] xcs, String str) {
        /*System.out.println("checkServerTrusted for authType: " + str); // RSA
        for(int idx=0; idx<xcs.length; idx++) {
            X509Certificate cert = xcs[idx];
            System.out.println("X500Principal: " + cert.getSubjectX500Principal().getName());
        }*/
    }
    @Override public X509Certificate[] getAcceptedIssuers() {
        return new java.security.cert.X509Certificate[0];
    }
}

UILabel is not auto-shrinking text to fit label size

In iOS 9 I just had to:

  1. Add constraints from the left and right of the label to the superview.
  2. Set the line break mode to clipping in IB.
  3. Set the number of lines to 1 in IB.

Someone recommended setting number of lines to 0, but for me this just made the label go to multiple lines...

npm ERR cb() never called

For anyone who has upgraded recently from 6.x to 6.7.0.

Deleting the /Users/{YOUR USERNAME}/.npm folder solved my issues with npm install.

I also, ran some of these commands suggested by https://npm.community/t/crash-npm-err-cb-never-called/858/93?u=jasonfoglia

sudo npm cache clean -f
sudo npm install -g n

But I'm not sure which actually worked until I deleted the folder. So if you experience this issue and just delete the .npm folder fixing your issue please note that in the comments.

How do I reverse a C++ vector?

#include<algorithm>
#include<vector>
#include<iostream>
using namespace std;
int main()
{
    vector<int>v1;
    for(int i=0; i<5; i++)
        v1.push_back(i*2);
    for(int i=0; i<v1.size(); i++)
        cout<<v1[i];    //02468
    reverse(v1.begin(),v1.end());
    
    for(int i=0; i<v1.size(); i++)
        cout<<v1[i];   //86420
}

Push items into mongo array via mongoose

The $push operator appends a specified value to an array.

{ $push: { <field1>: <value1>, ... } }

$push adds the array field with the value as its element.

Above answer fulfils all the requirements, but I got it working by doing the following

var objFriends = { fname:"fname",lname:"lname",surname:"surname" };
Friend.findOneAndUpdate(
   { _id: req.body.id }, 
   { $push: { friends: objFriends  } },
  function (error, success) {
        if (error) {
            console.log(error);
        } else {
            console.log(success);
        }
    });
)

What is event bubbling and capturing?

Bubbling

  Event propagate to the upto root element is **BUBBLING**.

Capturing

  Event propagate from body(root) element to eventTriggered Element is **CAPTURING**.

Detect if page has finished loading

there are two ways to do this in jquery depending what you are looking for..

using jquery you can do

  • //this will wait for the text assets to be loaded before calling this (the dom.. css.. js)

    $(document).ready(function(){...});
    
  • //this will wait for all the images and text assets to finish loading before executing

    $(window).load(function(){...});
    

Differences between ConstraintLayout and RelativeLayout

The only difference i've noted is that things set in a relative layout via drag and drop automatically have their dimensions relative to other elements inferred, so when you run the app what you see is what you get. However in the constraint layout even if you drag and drop an element in the design view, when you run the app things may be shifted around. This can easily be fixed by manually setting the constraints or, a more risky move being to right click the element in the component tree, selecting the constraint layout sub menu, then clicking 'infer constraints'. Hope this helps

How to print the ld(linker) search path

The most compatible command I've found for gcc and clang on Linux (thanks to armando.sano):

$ gcc -m64 -Xlinker --verbose  2>/dev/null | grep SEARCH | sed 's/SEARCH_DIR("=\?\([^"]\+\)"); */\1\n/g'  | grep -vE '^$'

if you give -m32, it will output the correct library directories.

Examples on my machine:

for g++ -m64:

/usr/x86_64-linux-gnu/lib64
/usr/i686-linux-gnu/lib64
/usr/local/lib/x86_64-linux-gnu
/usr/local/lib64
/lib/x86_64-linux-gnu
/lib64
/usr/lib/x86_64-linux-gnu
/usr/lib64
/usr/local/lib
/lib
/usr/lib

for g++ -m32:

/usr/i686-linux-gnu/lib32
/usr/local/lib32
/lib32
/usr/lib32
/usr/local/lib/i386-linux-gnu
/usr/local/lib
/lib/i386-linux-gnu
/lib
/usr/lib/i386-linux-gnu
/usr/lib

How to dynamically set bootstrap-datepicker's date value?

This works for me

$(".datepicker").datepicker("update", new Date());

Delete empty rows

I believe that your problem is that you're checking for an empty string using double quotes instead of single quotes. Try just changing to:

DELETE FROM table WHERE edit_user=''

how to check if a datareader is null or empty

I also experiencing this kind of problem but mine, i'm using DbDataReader as my generic reader (for SQL, Oracle, OleDb, etc.). If using DataTable, DataTable has this method:

DataTable dt = new DataTable();
dt.Rows[0].Table.Columns.Contains("SampleColumn");

using this I can determine if that column is existing in the result set that my query has. I'm also looking if DbDataReader has this capability.

What does the CSS rule "clear: both" do?

CSS float and clear

Sample Fiddle

Just try to remove clear:both property from the div with class sample and see how it follows floating divs.

How can you get the Manifest Version number from the App's (Layout) XML variables?

I believe that was already answered here.

String versionName = getPackageManager().getPackageInfo(getPackageName(), 0).versionName;

OR

int versionCode = getPackageManager().getPackageInfo(getPackageName(), 0).versionCode;

Access elements of parent window from iframe

Have the below js inside the iframe and use ajax to submit the form.

$(function(){

   $("form").submit(e){
        e.preventDefault();

       //Use ajax to submit the form
       $.ajax({
          url: this.action,
          data: $(this).serialize(),
          success: function(){
             window.parent.$("#target").load("urlOfThePageToLoad");
          });
       });

   });

});

Python NoneType object is not callable (beginner)

You should not pass the call function hi() to the loop() function, This will give the result.

def hi():     
  print('hi')

def loop(f, n):         #f repeats n times
  if n<=0:
    return
  else:
    f()             
    loop(f, n-1)    

loop(hi, 5)            # Do not use hi() function inside loop() function

Table 'mysql.user' doesn't exist:ERROR

Your database may be corrupt. Try to check if mysql.user exists:

use mysql;
select * from user;

If these are missing you can try recreating the tables by using

mysql_install_db

or you may have to clean (completely remove it) and reinstall MySQL.

Can I do Android Programming in C++, C?

You can use the Android NDK, but answers should note that the Android NDK app is not free to use and there's no clear open source route to programming Android on Android in an increasingly Android-driven market that began as open source, with Android developer support or the extensiveness of the NDK app, meaning you're looking at abandoning Android as any kind of first steps programming platform without payments.

Note: I consider subscription requests as payments under duress and this is a freemium context which continues to go undefeated by the open source community.

How to set the id attribute of a HTML element dynamically with angularjs (1.x)?

In case you came to this question but related to newer Angular version >= 2.0.

<div [id]="element.id"></div>

"Can't find Project or Library" for standard VBA functions

Even when all references are fine the prefix problem causes compile errors.

What about creating a find and replace sub for all 'built-in VBA functions' in all modules, like this:

replace text in code module

e.g. "= Date" will be replaced with "= VBA.Date".

e.g. " Date(" will be replaced with " VBA.Date(" .

(excluding "dim t As Date" or "mydate")

All vba functions for find and replace are written here :

vba functions list

How to find available directory objects on Oracle 11g system?

The ALL_DIRECTORIES data dictionary view will have information about all the directories that you have access to. That includes the operating system path

SELECT owner, directory_name, directory_path
  FROM all_directories

How to get C# Enum description from value?

You can't easily do this in a generic way: you can only convert an integer to a specific type of enum. As Nicholas has shown, this is a trivial cast if you only care about one kind of enum, but if you want to write a generic method that can handle different kinds of enums, things get a bit more complicated. You want a method along the lines of:

public static string GetEnumDescription<TEnum>(int value)
{
  return GetEnumDescription((Enum)((TEnum)value));  // error!
}

but this results in a compiler error that "int can't be converted to TEnum" (and if you work around this, that "TEnum can't be converted to Enum"). So you need to fool the compiler by inserting casts to object:

public static string GetEnumDescription<TEnum>(int value)
{
  return GetEnumDescription((Enum)(object)((TEnum)(object)value));  // ugly, but works
}

You can now call this to get a description for whatever type of enum is at hand:

GetEnumDescription<MyEnum>(1);
GetEnumDescription<YourEnum>(2);

PhpMyAdmin "Wrong permissions on configuration file, should not be world writable!"

try if install lampp

sudo chown www-data:www-data -R /opt/lampp/phpmyadmin/*
sudo chown www-data:www-data -R /opt/lampp/phpmyadmin

or if install phpmyadmin

sudo chown www-data:www-data -R /etc/phpmyadmin/*
sudo chown www-data:www-data -R /etc/phpmyadmin

Redirecting from cshtml page

Change to this:

@{ Response.Redirect("~/HOME/NoResults");}

Eclipse does not start when I run the exe?

The same thing was happening for me. All I had to do was uninstalled Java Update 8

comparing strings in vb

Dim MyString As String = "Hello World"
Dim YourString As String = "Hello World"
Console.WriteLine(String.Equals(MyString, YourString))

returns a bool True. This comparison is case-sensitive.

So in your example,

if String.Equals(string1, string2) and String.Equals(string3, string4) then
  ' do something
else
  ' do something else
end if

How do I tell matplotlib that I am done with a plot?

As stated from David Cournapeau, use figure().

import matplotlib
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab

plt.figure()
x = [1,10]
y = [30, 1000]
plt.loglog(x, y, basex=10, basey=10, ls="-")
plt.savefig("first.ps")


plt.figure()
x = [10,100]
y = [10, 10000]
plt.loglog(x, y, basex=10, basey=10, ls="-")
plt.savefig("second.ps")

Or subplot(121) / subplot(122) for the same plot, different position.

import matplotlib
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab

plt.subplot(121)
x = [1,10]
y = [30, 1000]
plt.loglog(x, y, basex=10, basey=10, ls="-")

plt.subplot(122)
x = [10,100]
y = [10, 10000]
plt.loglog(x, y, basex=10, basey=10, ls="-")
plt.savefig("second.ps")

QR Code encoding and decoding using zxing

For what it's worth, my groovy spike seems to work with both UTF-8 and ISO-8859-1 character encodings. Not sure what will happen when a non zxing decoder tries to decode the UTF-8 encoded image though... probably varies depending on the device.

// ------------------------------------------------------------------------------------
// Requires: groovy-1.7.6, jdk1.6.0_03, ./lib with zxing core-1.7.jar, javase-1.7.jar 
// Javadocs: http://zxing.org/w/docs/javadoc/overview-summary.html
// Run with: groovy -cp "./lib/*" zxing.groovy
// ------------------------------------------------------------------------------------

import com.google.zxing.*
import com.google.zxing.common.*
import com.google.zxing.client.j2se.*

import java.awt.image.BufferedImage
import javax.imageio.ImageIO

def class zxing {
    def static main(def args) {
        def filename = "./qrcode.png"
        def data = "This is a test to see if I can encode and decode this data..."
        def charset = "UTF-8" //"ISO-8859-1" 
        def hints = new Hashtable<EncodeHintType, String>([(EncodeHintType.CHARACTER_SET): charset])

        writeQrCode(filename, data, charset, hints, 100, 100)

        assert data == readQrCode(filename, charset, hints)
    }

    def static writeQrCode(def filename, def data, def charset, def hints, def width, def height) {
        BitMatrix matrix = new MultiFormatWriter().encode(new String(data.getBytes(charset), charset), BarcodeFormat.QR_CODE, width, height, hints)
        MatrixToImageWriter.writeToFile(matrix, filename.substring(filename.lastIndexOf('.')+1), new File(filename))
    }

    def static readQrCode(def filename, def charset, def hints) {
        BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(ImageIO.read(new FileInputStream(filename)))))
        Result result = new MultiFormatReader().decode(binaryBitmap, hints)

        result.getText()        
    }

}

Determining the last row in a single column

Never too late to post an alternative answer I hope. Here's a snippet of my Find last Cell. I'm primarily interested in speed. On a DB I'm using with around 150,000 rows this function took (average) 0.087 seconds to find solution compared to @Mogsdad elegant JS solution above which takes (average) 0.53 sec on same data. Both arrays were pre-loaded before the function call. It makes use of recursion to do a binary search. For 100,000+ rows you should find it takes no more than 15 to 20 hops to return it's result.

I've left the Log calls in so you can test it in the console first and see its workings.

/* @OnlyCurrentDoc */

function myLastRow() {

var ss=SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
var colArray = ss.getRange('A1:A').getDisplayValues();  // Change to relevant column label and put in Cache
var TestRow=ss.getLastRow();
var MaxRow=ss.getMaxRows(); 

Logger.log ('TestRow = %s',TestRow);
Logger.log ('MaxRow = %s',MaxRow);

var FoundRow=FindLastRow(TestRow,MaxRow);

Logger.log ('FoundRow = %s',FoundRow);    

function FindLastRow(v_TestRow,v_MaxRow) {

/* Some housekeeping/error trapping first
* 1) Check that LastRow doesn't = Max Rows. If so then suggest to add a few lines as this
* indicates the LastRow was the end of the sheet.
* 2) Check it's not a new sheet with no data ie, LastRow = 0 and/or cell A1 is empty.
* 3) A return result of 0 = an error otherwise any positive value is a valid result.
*/

 return   !(colArray[0][0]) ? 1                   // if first row is empty then presume it's a new empty sheet
        :!!(colArray[v_TestRow][0]) ? v_TestRow   // if the last row is not empty then column A was the longest
        : v_MaxRow==v_TestRow ? v_TestRow         // if Last=Max then consider adding a line here to extend row count, else
        : searchPair(0,v_TestRow);                // get on an find the last row
}

function searchPair(LowRow,HighRow){

var BinRow = ((LowRow+HighRow)/2)|0;   // force an INT to avoid row ambiguity

Logger.log ('LowRow/HighRow/BinRow = %s/%s/%s',LowRow, HighRow, BinRow);

/*   Check your log. You shoud find that the last row is always found in under 20 hops.
 *   This will be true whether your data rows are 100 or 100,000 long.
 *   The longest element of this script is loading the Cache (ColArray)
 */

 return   (!(colArray[BinRow-1][0]))^(!(colArray[BinRow][0])) ? BinRow
        : (!(colArray[BinRow-1][0]))&(!(colArray[BinRow][0])) ? searchPair(LowRow,BinRow-1)
        : (!!(colArray[BinRow-1][0]))|(!!(colArray[BinRow][0])) ? searchPair(BinRow+1,HighRow)
        : false;   // Error
 }
}

/* The premise for the above logic is that the binary search is looking for a specific pairing, <Text/No text>
 * on adjacent rows.  You said there are no gaps so the pairing <No Text/Text> is not tested as it's irrelevant.
 * If the logic finds <No Text/No Text> then it looks back up the sheet, if it finds <Text/Text> it looks further
 * down the sheet.  I think you'll find this is quite fast, especially on datasets > 100,000 rows.
 */

How do I obtain the frequencies of each value in an FFT?

The first bin in the FFT is DC (0 Hz), the second bin is Fs / N, where Fs is the sample rate and N is the size of the FFT. The next bin is 2 * Fs / N. To express this in general terms, the nth bin is n * Fs / N.

So if your sample rate, Fs is say 44.1 kHz and your FFT size, N is 1024, then the FFT output bins are at:

  0:   0 * 44100 / 1024 =     0.0 Hz
  1:   1 * 44100 / 1024 =    43.1 Hz
  2:   2 * 44100 / 1024 =    86.1 Hz
  3:   3 * 44100 / 1024 =   129.2 Hz
  4: ...
  5: ...
     ...
511: 511 * 44100 / 1024 = 22006.9 Hz

Note that for a real input signal (imaginary parts all zero) the second half of the FFT (bins from N / 2 + 1 to N - 1) contain no useful additional information (they have complex conjugate symmetry with the first N / 2 - 1 bins). The last useful bin (for practical aplications) is at N / 2 - 1, which corresponds to 22006.9 Hz in the above example. The bin at N / 2 represents energy at the Nyquist frequency, i.e. Fs / 2 ( = 22050 Hz in this example), but this is in general not of any practical use, since anti-aliasing filters will typically attenuate any signals at and above Fs / 2.

How to encode the filename parameter of Content-Disposition header in HTTP?

There is discussion of this, including links to browser testing and backwards compatibility, in the proposed RFC 5987, "Character Set and Language Encoding for Hypertext Transfer Protocol (HTTP) Header Field Parameters."

RFC 2183 indicates that such headers should be encoded according to RFC 2184, which was obsoleted by RFC 2231, covered by the draft RFC above.

Convert date yyyyMMdd to system.datetime format

have at look at the static methods DateTime.Parse() and DateTime.TryParse(). They will allow you to pass in your date string and a format string, and get a DateTime object in return.

http://msdn.microsoft.com/en-us/library/6fw7727c.aspx

What is the difference between public, private, and protected?

?? Here is an easy way to remember the scope of public, protected and private.

PUBLIC:

  • public scope: A public variable/function is available to both objects and other classes.

PROTECTED:

  • protected scope: A protected variable/function is available to all the classes that extend the current class.
  • No! Objects cannot access this scope

PRIVATE:

  • private scope: A private variable/function is only visible in the current class where it is being defined.
  • No! Class that extend the current class cannot access this scope.
  • No! Objects cannot access this scope.

Read the Visibility of a method or variable on PHP Manual.

How do I find which transaction is causing a "Waiting for table metadata lock" state?

mysql 5.7 exposes metadata lock information through the performance_schema.metadata_locks table.

Documentation here

How to include file in a bash shell script

Syntax is source <file-name>

ex. source config.sh

script - config.sh

USERNAME="satish"
EMAIL="[email protected]"

calling script -

#!/bin/bash
source config.sh
echo Welcome ${USERNAME}!
echo Your email is ${EMAIL}.

You can learn to include a bash script in another bash script here.

Android: how to get the current day of the week (Monday, etc...) in the user's language?

I know already answered but who looking for 'Fri' like this

for Fri -

SimpleDateFormat sdf = new SimpleDateFormat("EEE");
Date d = new Date();
String dayOfTheWeek = sdf.format(d);

and who wants full date string they can use 4E for Friday

For Friday-

SimpleDateFormat sdf = new SimpleDateFormat("EEEE");
Date d = new Date();
String dayOfTheWeek = sdf.format(d);

Enjoy...

Check if a string contains a number

This too will work.

if any(i.isdigit() for i in s):
    print("True")

How to add pandas data to an existing csv file?

You can append to a csv by opening the file in append mode:

with open('my_csv.csv', 'a') as f:
    df.to_csv(f, header=False)

If this was your csv, foo.csv:

,A,B,C
0,1,2,3
1,4,5,6

If you read that and then append, for example, df + 6:

In [1]: df = pd.read_csv('foo.csv', index_col=0)

In [2]: df
Out[2]:
   A  B  C
0  1  2  3
1  4  5  6

In [3]: df + 6
Out[3]:
    A   B   C
0   7   8   9
1  10  11  12

In [4]: with open('foo.csv', 'a') as f:
             (df + 6).to_csv(f, header=False)

foo.csv becomes:

,A,B,C
0,1,2,3
1,4,5,6
0,7,8,9
1,10,11,12

List<Map<String, String>> vs List<? extends Map<String, String>>

Today, I have used this feature, so here's my very fresh real-life example. (I have changed class and method names to generic ones so they won't distract from the actual point.)

I have a method that's meant to accept a Set of A objects that I originally wrote with this signature:

void myMethod(Set<A> set)

But it want to actually call it with Sets of subclasses of A. But this is not allowed! (The reason for that is, myMethod could add objects to set that are of type A, but not of the subtype that set's objects are declared to be at the caller's site. So this could break the type system if it were possible.)

Now here come generics to the rescue, because it works as intended if I use this method signature instead:

<T extends A> void myMethod(Set<T> set)

or shorter, if you don't need to use the actual type in the method body:

void myMethod(Set<? extends A> set)

This way, set's type becomes a collection of objects of the actual subtype of A, so it becomes possible to use this with subclasses without endangering the type system.

How to get time in milliseconds since the unix epoch in Javascript?

Date.now() returns a unix timestamp in milliseconds.

_x000D_
_x000D_
const now = Date.now(); // Unix timestamp in milliseconds_x000D_
console.log( now );
_x000D_
_x000D_
_x000D_

Prior to ECMAScript5 (I.E. Internet Explorer 8 and older) you needed to construct a Date object, from which there are several ways to get a unix timestamp in milliseconds:

_x000D_
_x000D_
console.log( +new Date );_x000D_
console.log( (new Date).getTime() );_x000D_
console.log( (new Date).valueOf() );
_x000D_
_x000D_
_x000D_

Is there "\n" equivalent in VBscript?

As David and Remou pointed out, vbCrLf if you want a carriage-return-linefeed combination. Otherwise, Chr(13) and Chr(10) (although some VB-derivatives have vbCr and vbLf; VBScript may well have those, worth checking before using Chr).

Can I use Homebrew on Ubuntu?

As of February 2018, installing brew on Ubuntu (mine is 17.10) machine is as simple as:

sudo apt install linuxbrew-wrapper

Then, on first brew execution (just type brew --help) you will be asked for two installation options:

me@computer:~/$ brew --help
==> Select the Linuxbrew installation directory
- Enter your password to install to /home/linuxbrew/.linuxbrew (recommended)
- Press Control-D to install to /home/me/.linuxbrew
- Press Control-C to cancel installation
[sudo] password for me:

For recommended option type your password (if your current user is in sudo group), or, if you prefer installing all the dependencies in your own home folder, hit Ctrl+D. Enjoy.

Alternative for frames in html5 using iframes

HTML 5 does support iframes. There were a few interesting attributes added like "sandbox" and "srcdoc".

http://www.w3schools.com/html5/tag_iframe.asp

or you can use

<object data="framed.html" type="text/html"><p>This is the fallback code!</p></object>

Simple way to copy or clone a DataRow?

You can use ImportRow method to copy Row from DataTable to DataTable with the same schema:

var row = SourceTable.Rows[RowNum];
DestinationTable.ImportRow(row);

Update:

With your new Edit, I believe:

var desRow = dataTable.NewRow();
var sourceRow = dataTable.Rows[rowNum];
desRow.ItemArray = sourceRow.ItemArray.Clone() as object[];

will work

How to get to Model or Viewbag Variables in a Script Tag

try this method

<script type="text/javascript">

    function set(value) {
        return value;
    }

    alert(set(@Html.Raw(Json.Encode(Model.Message)))); // Message set from controller
    alert(set(@Html.Raw(Json.Encode(ViewBag.UrMessage))));

</script>

Thanks

The AWS Access Key Id does not exist in our records

you can configure profiles in the bash_profile file using

<profile_name>
aws_access_key_id = <access_key>
aws_secret_access_key = <acces_key_secret>

if you are using multiple profiles. then use:

aws s3 ls --profile <profile_name>

Google Maps API Multiple Markers with Infowindows

You could use a closure. Just modify your code like this:

google.maps.event.addListener(marker,'click', (function(marker,content,infowindow){ 
    return function() {
        infowindow.setContent(content);
        infowindow.open(map,marker);
    };
})(marker,content,infowindow));  

Here is the DEMO

call a function in success of datatable ajax call

You can use this:

"drawCallback": function(settings) {
   console.log(settings.json);
   //do whatever  
},

What are the differences between B trees and B+ trees?

The primary distinction between B-tree and B+tree is that B-tree eliminates the redundant storage of search key values.Since search keys are not repeated in the B-tree,we may not be able to store the index using fewer tree nodes than in corresponding B+tree index.However,since search key that appear in non-leaf nodes appear nowhere else in B-tree,we are forced to include an additional pointer field for each search key in a non-leaf node. Their are space advantages for B-tree, as repetition does not occur and can be used for large indices.

node.js remove file

As the accepted answer, use fs.unlink to delete files.

But according to Node.js documentation

Using fs.stat() to check for the existence of a file before calling fs.open(), fs.readFile() or fs.writeFile() is not recommended. Instead, user code should open/read/write the file directly and handle the error raised if the file is not available.

To check if a file exists without manipulating it afterwards, fs.access() is recommended.

to check files can be deleted or not, Use fs.access instead

fs.access('/etc/passwd', fs.constants.R_OK | fs.constants.W_OK, (err) => {
  console.log(err ? 'no access!' : 'can read/write');
});

Html.DropDownList - Disabled/Readonly

try with @disabled and jquery, in that way you can get the value on the Controller.

Html.DropDownList("Types", Model.Types, new {@class = "your_class disabled", @disabled= "disabled" })

Add a class called "disabled" so you can enabled by searching that class(in case of multiples disabled fields), then you can use a "setTimeout" in case of not entering controller by validation attributes

<script>

  function clickSubmit() {
    $("select.disabled").attr("disabled", false);
    setTimeout(function () {
        $("select.disabled").attr("disabled", true);
    }, 500);
  }
</script>

submit button like this.

 <button type="submit" value="Submit" onclick="clickSubmit();">Save</button>

in case of inputs, just use @readonly="readonly"

@Html.TextBoxFor("Types",Model.Types, new { @class = "form-control", @readonly= "readonly" })

Generate SHA hash in C++ using OpenSSL library

Here is OpenSSL example of calculating sha-1 digest using BIO:

#include <openssl/bio.h>
#include <openssl/evp.h>

std::string sha1(const std::string &input)
{
    BIO * p_bio_md  = nullptr;
    BIO * p_bio_mem = nullptr;

    try
    {
        // make chain: p_bio_md <-> p_bio_mem
        p_bio_md = BIO_new(BIO_f_md());
        if (!p_bio_md) throw std::bad_alloc();
        BIO_set_md(p_bio_md, EVP_sha1());

        p_bio_mem = BIO_new_mem_buf((void*)input.c_str(), input.length());
        if (!p_bio_mem) throw std::bad_alloc();
        BIO_push(p_bio_md, p_bio_mem);

        // read through p_bio_md
        // read sequence: buf <<-- p_bio_md <<-- p_bio_mem
        std::vector<char> buf(input.size());
        for (;;)
        {
            auto nread = BIO_read(p_bio_md, buf.data(), buf.size());
            if (nread  < 0) { throw std::runtime_error("BIO_read failed"); }
            if (nread == 0) { break; } // eof
        }

        // get result
        char md_buf[EVP_MAX_MD_SIZE];
        auto md_len = BIO_gets(p_bio_md, md_buf, sizeof(md_buf));
        if (md_len <= 0) { throw std::runtime_error("BIO_gets failed"); }

        std::string result(md_buf, md_len);

        // clean
        BIO_free_all(p_bio_md);

        return result;
    }
    catch (...)
    {
        if (p_bio_md) { BIO_free_all(p_bio_md); }
        throw;
    }
}

Though it's longer than just calling SHA1 function from OpenSSL, but it's more universal and can be reworked for using with file streams (thus processing data of any length).

How to swap String characters in Java?

Here's a solution with a StringBuilder. It supports padding resulting strings with uneven string length with a padding character. As you've guessed this method is made for hexadecimal-nibble-swapping.

/**
 * Swaps every character at position i with the character at position i + 1 in the given
 * string.
 */
public static String swapCharacters(final String value, final boolean padding)
{
   if ( value == null )
   {
      return null;
   }

   final StringBuilder stringBuilder = new StringBuilder();
   int posA = 0;
   int posB = 1;
   final char padChar = 'F';

   // swap characters
   while ( posA < value.length() && posB < value.length() )
   {
      stringBuilder.append( value.charAt( posB ) ).append( value.charAt( posA ) );
      posA += 2;
      posB += 2;
   }

   // if resulting string is still smaller than original string we missed the last
   // character
   if ( stringBuilder.length() < value.length() )
   {
      stringBuilder.append( value.charAt( posA ) );
   }

   // add the padding character for uneven strings
   if ( padding && value.length() % 2 != 0 )
   {
      stringBuilder.append( padChar );
   }

   return stringBuilder.toString();
}

Javascript switch vs. if...else if...else

Pointy's answer suggests the use of an object literal as an alternative to switch or if/else. I like this approach too, but the code in the answer creates a new map object every time the dispatch function is called:

function dispatch(funCode) {
  var map = {
    'explode': function() {
      prepExplosive();
      if (flammable()) issueWarning();
      doExplode();
    },

    'hibernate': function() {
      if (status() == 'sleeping') return;
      // ... I can't keep making this stuff up
    },
    // ...
  };

  var thisFun = map[funCode];
  if (thisFun) thisFun();
}

If map contains a large number of entries, this can create significant overhead. It's better to set up the action map only once and then use the already-created map each time, for example:

var actions = {
    'explode': function() {
        prepExplosive();
        if( flammable() ) issueWarning();
        doExplode();
    },

    'hibernate': function() {
        if( status() == 'sleeping' ) return;
        // ... I can't keep making this stuff up
    },
    // ...
};

function dispatch( name ) {
    var action = actions[name];
    if( action ) action();
}

Find out where MySQL is installed on Mac OS X

for me it was installed in /usr/local/opt

The command I used for installation is brew install [email protected]

How to run a Powershell script from the command line and pass a directory as a parameter

Change your code to the following :

Function Foo($directory)
    {
        echo $directory
    }

    if ($args.Length -eq 0)
    {
        echo "Usage: Foo <directory>"
    }
    else
    {
        Foo([string[]]$args)
    }

And then invoke it as:

powershell -ExecutionPolicy RemoteSigned -File "c:\foo.ps1" "c:\Documents and Settings" "c:\test"

How do I find the time difference between two datetime objects in python?

Using datetime example

>>> from datetime import datetime
>>> then = datetime(2012, 3, 5, 23, 8, 15)        # Random date in the past
>>> now  = datetime.now()                         # Now
>>> duration = now - then                         # For build-in functions
>>> duration_in_s = duration.total_seconds()      # Total number of seconds between dates

Duration in years

>>> years = divmod(duration_in_s, 31536000)[0]    # Seconds in a year=365*24*60*60 = 31536000.

Duration in days

>>> days  = duration.days                         # Build-in datetime function
>>> days  = divmod(duration_in_s, 86400)[0]       # Seconds in a day = 86400

Duration in hours

>>> hours = divmod(duration_in_s, 3600)[0]        # Seconds in an hour = 3600

Duration in minutes

>>> minutes = divmod(duration_in_s, 60)[0]        # Seconds in a minute = 60

Duration in seconds

[!] See warning about using duration in seconds in the bottom of this post

>>> seconds = duration.seconds                    # Build-in datetime function
>>> seconds = duration_in_s

Duration in microseconds

[!] See warning about using duration in microseconds in the bottom of this post

>>> microseconds = duration.microseconds          # Build-in datetime function

Total duration between the two dates

>>> days    = divmod(duration_in_s, 86400)        # Get days (without [0]!)
>>> hours   = divmod(days[1], 3600)               # Use remainder of days to calc hours
>>> minutes = divmod(hours[1], 60)                # Use remainder of hours to calc minutes
>>> seconds = divmod(minutes[1], 1)               # Use remainder of minutes to calc seconds
>>> print("Time between dates: %d days, %d hours, %d minutes and %d seconds" % (days[0], hours[0], minutes[0], seconds[0]))

or simply:

>>> print(now - then)

Edit 2019 Since this answer has gained traction, I'll add a function, which might simplify the usage for some

from datetime import datetime

def getDuration(then, now = datetime.now(), interval = "default"):

    # Returns a duration as specified by variable interval
    # Functions, except totalDuration, returns [quotient, remainder]

    duration = now - then # For build-in functions
    duration_in_s = duration.total_seconds() 
    
    def years():
      return divmod(duration_in_s, 31536000) # Seconds in a year=31536000.

    def days(seconds = None):
      return divmod(seconds if seconds != None else duration_in_s, 86400) # Seconds in a day = 86400

    def hours(seconds = None):
      return divmod(seconds if seconds != None else duration_in_s, 3600) # Seconds in an hour = 3600

    def minutes(seconds = None):
      return divmod(seconds if seconds != None else duration_in_s, 60) # Seconds in a minute = 60

    def seconds(seconds = None):
      if seconds != None:
        return divmod(seconds, 1)   
      return duration_in_s

    def totalDuration():
        y = years()
        d = days(y[1]) # Use remainder to calculate next variable
        h = hours(d[1])
        m = minutes(h[1])
        s = seconds(m[1])

        return "Time between dates: {} years, {} days, {} hours, {} minutes and {} seconds".format(int(y[0]), int(d[0]), int(h[0]), int(m[0]), int(s[0]))

    return {
        'years': int(years()[0]),
        'days': int(days()[0]),
        'hours': int(hours()[0]),
        'minutes': int(minutes()[0]),
        'seconds': int(seconds()),
        'default': totalDuration()
    }[interval]

# Example usage
then = datetime(2012, 3, 5, 23, 8, 15)
now = datetime.now()

print(getDuration(then)) # E.g. Time between dates: 7 years, 208 days, 21 hours, 19 minutes and 15 seconds
print(getDuration(then, now, 'years'))      # Prints duration in years
print(getDuration(then, now, 'days'))       #                    days
print(getDuration(then, now, 'hours'))      #                    hours
print(getDuration(then, now, 'minutes'))    #                    minutes
print(getDuration(then, now, 'seconds'))    #                    seconds

Warning: Caveat about built-in .seconds and .microseconds
datetime.seconds and datetime.microseconds are capped to [0,86400) and [0,10^6) respectively.

They should be used carefully if timedelta is bigger than the max returned value.

Examples:

end is 1h and 200µs after start:

>>> start = datetime(2020,12,31,22,0,0,500)
>>> end = datetime(2020,12,31,23,0,0,700)
>>> delta = end - start
>>> delta.microseconds
RESULT: 200
EXPECTED: 3600000200

end is 1d and 1h after start:

>>> start = datetime(2020,12,30,22,0,0)
>>> end = datetime(2020,12,31,23,0,0)
>>> delta = end - start
>>> delta.seconds
RESULT: 3600
EXPECTED: 90000

The entitlements specified...profile. (0xE8008016). Error iOS 4.2

This is what solved my problem: Deleting the path in the Code Signing Entitlements section of the Targets build settings.

How can I get list of values from dict?

There should be one - and preferably only one - obvious way to do it.

Therefore list(dictionary.values()) is the one way.

Yet, considering Python3, what is quicker?

[*L] vs. [].extend(L) vs. list(L)

small_ds = {x: str(x+42) for x in range(10)}
small_df = {x: float(x+42) for x in range(10)}

print('Small Dict(str)')
%timeit [*small_ds.values()]
%timeit [].extend(small_ds.values())
%timeit list(small_ds.values())

print('Small Dict(float)')
%timeit [*small_df.values()]
%timeit [].extend(small_df.values())
%timeit list(small_df.values())

big_ds = {x: str(x+42) for x in range(1000000)}
big_df = {x: float(x+42) for x in range(1000000)}

print('Big Dict(str)')
%timeit [*big_ds.values()]
%timeit [].extend(big_ds.values())
%timeit list(big_ds.values())

print('Big Dict(float)')
%timeit [*big_df.values()]
%timeit [].extend(big_df.values())
%timeit list(big_df.values())
Small Dict(str)
256 ns ± 3.37 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
338 ns ± 0.807 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
336 ns ± 1.9 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

Small Dict(float)
268 ns ± 0.297 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
343 ns ± 15.2 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
336 ns ± 0.68 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

Big Dict(str)
17.5 ms ± 142 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
16.5 ms ± 338 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
16.2 ms ± 19.7 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)

Big Dict(float)
13.2 ms ± 41 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
13.1 ms ± 919 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
12.8 ms ± 578 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)

Done on Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz.

# Name                    Version                   Build
ipython                   7.5.0            py37h24bf2e0_0

The result

  1. For small dictionaries * operator is quicker
  2. For big dictionaries where it matters list() is maybe slightly quicker

Allow multi-line in EditText view in Android?

Just add this android:inputType="textMultiLine" in XML file on relevant field.

Easy way to concatenate two byte arrays

For two or multiple arrays, this simple and clean utility method can be used:

/**
 * Append the given byte arrays to one big array
 *
 * @param arrays The arrays to append
 * @return The complete array containing the appended data
 */
public static final byte[] append(final byte[]... arrays) {
    final ByteArrayOutputStream out = new ByteArrayOutputStream();
    if (arrays != null) {
        for (final byte[] array : arrays) {
            if (array != null) {
                out.write(array, 0, array.length);
            }
        }
    }
    return out.toByteArray();
}

How to get the sizes of the tables of a MySQL database?

SELECT TABLE_NAME AS "Table Name", 
table_rows AS "Quant of Rows", ROUND( (
data_length + index_length
) /1024, 2 ) AS "Total Size Kb"
FROM information_schema.TABLES
WHERE information_schema.TABLES.table_schema = 'YOUR SCHEMA NAME/DATABASE NAME HERE'
LIMIT 0 , 30

You can get schema name from "information_schema" -> SCHEMATA table -> "SCHEMA_NAME" column


Additional You can get size of the mysql databases as following.

SELECT table_schema "DB Name", 
Round(Sum(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB" 
FROM   information_schema.tables 
GROUP  BY table_schema; 

Result

DB Name              |      DB Size in MB

mydatabase_wrdp             39.1
information_schema          0.0

You can get additional details in here.

How to check if a service is running on Android?

onDestroy isn't always called in the service so this is useless!

For example: Just run the app again with one change from Eclipse. The application is forcefully exited using SIG: 9.

Type of expression is ambiguous without more context Swift

Explicitly declaring the inputs for that mapping function should do the trick:

let imageToDeleteParameters  = imagesToDelete.map {
    (whatever : WhateverClass) -> Dictionary<String, Any> in
    ["id": whatever.id, "url": whatever.url.absoluteString, "_destroy": true]
}

Substitute the real class of "$0" for "WhateverClass" in that code snippet, and it should work.

Convert Difference between 2 times into Milliseconds?

You have to convert textbox's values to DateTime (t1,t2), then:

DateTime t1,t2;
t1 = DateTime.Parse(textbox1.Text);
t2 = DateTime.Parse(textbox2.Text);
int diff = ((TimeSpan)(t2 - t1)).TotalMilliseconds;

Or use DateTime.TryParse(textbox1, out t1); Error handling is up to you.

Python + Regex: AttributeError: 'NoneType' object has no attribute 'groups'

You are getting AttributeError because you're calling groups on None, which hasn't any methods.

regex.search returning None means the regex couldn't find anything matching the pattern from supplied string.

when using regex, it is nice to check whether a match has been made:

Result = re.search(SearchStr, htmlString)

if Result:
    print Result.groups()

How do I connect to a specific Wi-Fi network in Android programmatically?

Before connecting WIFI network you need to check security type of the WIFI network ScanResult class has a capabilities. This field gives you type of network

Refer: https://developer.android.com/reference/android/net/wifi/ScanResult.html#capabilities

There are three types of WIFI networks.

First, instantiate a WifiConfiguration object and fill in the network’s SSID (note that it has to be enclosed in double quotes), set the initial state to disabled, and specify the network’s priority (numbers around 40 seem to work well).

WifiConfiguration wfc = new WifiConfiguration();

wfc.SSID = "\"".concat(ssid).concat("\"");
wfc.status = WifiConfiguration.Status.DISABLED;
wfc.priority = 40;

Now for the more complicated part: we need to fill several members of WifiConfiguration to specify the network’s security mode. For open networks.

wfc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
wfc.allowedAuthAlgorithms.clear();
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP104);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);

For networks using WEP; note that the WEP key is also enclosed in double quotes.

wfc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
wfc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN);
wfc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.SHARED);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP104);

if (isHexString(password)) wfc.wepKeys[0] = password;
else wfc.wepKeys[0] = "\"".concat(password).concat("\"");
wfc.wepTxKeyIndex = 0;

For networks using WPA and WPA2, we can set the same values for either.

wfc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
wfc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP104);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);

wfc.preSharedKey = "\"".concat(password).concat("\"");

Finally, we can add the network to the WifiManager’s known list

WifiManager wfMgr = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
int networkId = wfMgr.addNetwork(wfc);
if (networkId != -1) {
 // success, can call wfMgr.enableNetwork(networkId, true) to connect
} 

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

You can do this in the 'Conditional Formatting' tool in the Home tab of Excel 2010.

Assuming the existing rule is 'Use a formula to dtermine which cells to format':

Edit the existing rule, so that the 'Formula' refers to relative rows and columns (i.e. remove $s), and then in the 'Applies to' box, click the icon to make the sheet current and select the cells you want the formatting to apply to (absolute cell references are ok here), then go back to the tool panel and click Apply.

This will work assuming the relative offsets are appropriate throughout your desired apply-to range.

You can copy conditional formatting from one cell to another or a range using copy and paste-special with formatting only, assuming you do not mind copying the normal formats.

SelectSingleNode returning null for known good xml node path using XPath

just use //id instead of /id. It works fine in my code

How to copy multiple files in one layer using a Dockerfile?

simple

COPY README.md  package.json gulpfile.js __BUILD_NUMBER ./

from the doc

If multiple resources are specified, either directly or due to the use of a wildcard, then must be a directory, and it must end with a slash /.

Sending a file over TCP sockets in Python

You can send some flag to stop while loop in server

for example

Server side:

import socket
s = socket.socket()
s.bind(("localhost", 5000))
s.listen(1)
c,a = s.accept()
filetodown = open("img.png", "wb")
while True:
   print("Receiving....")
   data = c.recv(1024)
   if data == b"DONE":
           print("Done Receiving.")
           break
   filetodown.write(data)
filetodown.close()
c.send("Thank you for connecting.")
c.shutdown(2)
c.close()
s.close()
#Done :)

Client side:

import socket
s = socket.socket()
s.connect(("localhost", 5000))
filetosend = open("img.png", "rb")
data = filetosend.read(1024)
while data:
    print("Sending...")
    s.send(data)
    data = filetosend.read(1024)
filetosend.close()
s.send(b"DONE")
print("Done Sending.")
print(s.recv(1024))
s.shutdown(2)
s.close()
#Done :)

Head and tail in one line

Python 2, using lambda

>>> head, tail = (lambda lst: (lst[0], lst[1:]))([1, 1, 2, 3, 5, 8, 13, 21, 34, 55])
>>> head
1
>>> tail
[1, 2, 3, 5, 8, 13, 21, 34, 55]

Spring: @Component versus @Bean

@Bean was created to avoid coupling Spring and your business rules in compile time. It means you can reuse your business rules in other frameworks like PlayFramework or JEE.

Moreover, you have total control on how create beans, where it is not enough the default Spring instantation.

I wrote a post talking about it.

https://coderstower.com/2019/04/23/factory-methods-decoupling-ioc-container-abstraction/

Getting a list of files in a directory with a glob

You can achieve this pretty easily with the help of NSPredicate, like so:

NSString *bundleRoot = [[NSBundle mainBundle] bundlePath];
NSFileManager *fm = [NSFileManager defaultManager];
NSArray *dirContents = [fm contentsOfDirectoryAtPath:bundleRoot error:nil];
NSPredicate *fltr = [NSPredicate predicateWithFormat:@"self ENDSWITH '.jpg'"];
NSArray *onlyJPGs = [dirContents filteredArrayUsingPredicate:fltr];

If you need to do it with NSURL instead it looks like this:

NSURL *bundleRoot = [[NSBundle mainBundle] bundleURL];
NSArray * dirContents = 
      [fm contentsOfDirectoryAtURL:bundleRoot
        includingPropertiesForKeys:@[] 
                           options:NSDirectoryEnumerationSkipsHiddenFiles
                             error:nil];
NSPredicate * fltr = [NSPredicate predicateWithFormat:@"pathExtension='jpg'"];
NSArray * onlyJPGs = [dirContents filteredArrayUsingPredicate:fltr];

Remove spaces from a string in VB.NET

"Spaces" in the original post could refer to whitespace, and no answer yet shows how to remove ALL whitespace from a string. For that regular expressions are the most flexible approach I've found.

Below is a console application where you can see the difference between replacing just spaces or all whitespace.

You can find more about .NET regular expressions at http://msdn.microsoft.com/en-us/library/hs600312.aspx and http://msdn.microsoft.com/en-us/library/az24scfc.aspx

Imports System.Text.RegularExpressions
Module TestRegExp
    Sub Main()
        ' Use to match all whitespace (note the lowercase s matters)
        Dim regWhitespace As New Regex("\s")

        ' Use to match space characters only
        Dim regSpace As New Regex(" ")

        Dim testString As String = "First Line" + vbCrLf + _
        "Second line followed by 2 tabs" + vbTab + vbTab + _
        "End of tabs"

        Console.WriteLine("Test string :")
        Console.WriteLine(testString)

        Console.WriteLine("Replace all whitespace :")
        ' This prints the string on one line with no spacing at all
        Console.WriteLine(regWhitespace.Replace(testString, String.Empty))

        Console.WriteLine("Replace all spaces :")
        ' This removes spaces, but retains the tabs and new lines
        Console.WriteLine(regSpace.Replace(testString, String.Empty))

        Console.WriteLine("Press any key to finish")
        Console.ReadKey()
    End Sub
End Module

How to remove focus from input field in jQuery?

Use .blur().

The blur event is sent to an element when it loses focus. Originally, this event was only applicable to form elements, such as <input>. In recent browsers, the domain of the event has been extended to include all element types. An element can lose focus via keyboard commands, such as the Tab key, or by mouse clicks elsewhere on the page.

$("#myInputID").blur(); 

Find empty or NaN entry in Pandas Dataframe

you also do something good:

text_empty = df['column name'].str.len() > -1

df.loc[text_empty].index

The results will be the rows which are empty & it's index number.

mysql after insert trigger which updates another table's column

Maybe remove the semi-colon after set because now the where statement doesn't belong to the update statement. Also the idRequest could be a problem, better write BookingRequest.idRequest

How can I make an EXE file from a Python program?

I found this presentation to be very helpfull.

How I Distribute Python applications on Windows - py2exe & InnoSetup

From the site:

There are many deployment options for Python code. I'll share what has worked well for me on Windows, packaging command line tools and services using py2exe and InnoSetup. I'll demonstrate a simple build script which creates windows binaries and an InnoSetup installer in one step. In addition, I'll go over common errors which come up when using py2exe and hints on troubleshooting them. This is a short talk, so there will be a follow-up Open Space session to share experience and help each other solve distribution problems.

jQuery has deprecated synchronous XMLHTTPRequest

It was mentioned as a comment by @henri-chan, but I think it deserves some more attention:

When you update the content of an element with new html using jQuery/javascript, and this new html contains <script> tags, those are executed synchronously and thus triggering this error. Same goes for stylesheets.

You know this is happening when you see (multiple) scripts or stylesheets being loaded as XHR in the console window. (firefox).

Delete a dictionary item if the key exists

Approach: calculate keys to remove, mutate dict

Let's call keys the list/iterator of keys that you are given to remove. I'd do this:

keys_to_remove = set(keys).intersection(set(mydict.keys()))
for key in keys_to_remove:
    del mydict[key]

You calculate up front all the affected items and operate on them.

Approach: calculate keys to keep, make new dict with those keys

I prefer to create a new dictionary over mutating an existing one, so I would probably also consider this:

keys_to_keep = set(mydict.keys()) - set(keys)
new_dict = {k: v for k, v in mydict.iteritems() if k in keys_to_keep}

or:

keys_to_keep = set(mydict.keys()) - set(keys)
new_dict = {k: mydict[k] for k in keys_to_keep}

In Python, how do I split a string and keep the separators?

I found this generator based approach more satisfying:

def split_keep(string, sep):
    """Usage:
    >>> list(split_keep("a.b.c.d", "."))
    ['a.', 'b.', 'c.', 'd']
    """
    start = 0
    while True:
        end = string.find(sep, start) + 1
        if end == 0:
            break
        yield string[start:end]
        start = end
    yield string[start:]

It avoids the need to figure out the correct regex, while in theory should be fairly cheap. It doesn't create new string objects and, delegates most of the iteration work to the efficient find method.

... and in Python 3.8 it can be as short as:

def split_keep(string, sep):
    start = 0
    while (end := string.find(sep, start) + 1) > 0:
        yield string[start:end]
        start = end
    yield string[start:]

What is the best way to trigger onchange event in react js

At least on text inputs, it appears that onChange is listening for input events:

var event = new Event('input', { bubbles: true });
element.dispatchEvent(event);

What is a stack trace, and how can I use it to debug my application errors?

Just to add to the other examples, there are inner(nested) classes that appear with the $ sign. For example:

public class Test {

    private static void privateMethod() {
        throw new RuntimeException();
    }

    public static void main(String[] args) throws Exception {
        Runnable runnable = new Runnable() {
            @Override public void run() {
                privateMethod();
            }
        };
        runnable.run();
    }
}

Will result in this stack trace:

Exception in thread "main" java.lang.RuntimeException
        at Test.privateMethod(Test.java:4)
        at Test.access$000(Test.java:1)
        at Test$1.run(Test.java:10)
        at Test.main(Test.java:13)

Get all messages from Whatsapp

Edit

As WhatsApp put some effort into improving their encryption system, getting the data is not that easy anymore. With newer versions of WhatsApp it is no longer possible to use adb backup. Apps can deny backups and the WhatsApp client does that. If you happen to have a rooted phone, you can use a root shell to get the unencrypted database file.

If you do not have root, you can still decrypt the data if you have an old WhatsApp APK. Find a version that still allows backups. Then you can make a backup of the app's data folder, which will contain an encryption key named, well, key.

Now you'll need the encrypted database. Use a file explorer of your choice or, if you like the command line more, use adb:

adb pull /sdcard/WhatsApp/Databases/msgstore.db.crypt12

Using the two files, you could now use https://gitlab.com/digitalinternals/whatsapp-crypt12 to get the plain text database. It is no longer possible to use Linux board tools like openssl because WhatsApp seems to use a modified version of the Spongy Castle API for cryptography that openssl does not understand.

Original Answer (only for the old crypt7)

As whatsapp is now using the crypt7 format, it is not that easy to get and decrypt the database anymore. There is a working approach using ADB and USB debugging.

You can either get the encryption keys via ADB and decrypt the message database stored on /sdcard, or you just get the plain version of the database via ADB backup, what seems to be the easier option.

To get the database, do the following:

Connect your Android phone to your computer. Now run

adb backup -f whatsapp_backup.ab -noapk com.whatsapp

to backup all files WhatsApp has created in its private folder.
You will get a zlib compressed file using tar format with some ADB headers. We need to get rid of those headers first as they confuse the decompression command:

dd if=whatsapp_backup.ab ibs=1 skip=24 of=whatsapp_backup.ab.nohdr

The file can now be decompressed:

cat whatsapp_backup.ab.nohdr | python -c "import zlib,sys;sys.stdout.write(zlib.decompress(sys.stdin.read()))" 1> whatsapp_backup.tar

This command runs Python and decompresses the file using zlib to whatsapp_backup.tar
Now we can unTAR the file:

tar xf whatsapp_backup.tar

The archive is now extracted to your current working directory and you can find the databases (msgstore.db and wa.db) in apps/com.whatsapp/db/

How do I shrink my SQL Server Database?

You also have to modify the minimum size of the data and log files. DBCC SHRINKDATABASE will shrink the data inside the files you already have allocated. To shrink a file to a size smaller than its minimum size, use DBCC SHRINKFILE and specify the new size.

embedding image in html email

The other solution is attaching the image as attachment and then referencing it html code using cid.

HTML Code:

<html>
    <head>
    </head>
    <body>
        <img width=100 height=100 id="1" src="cid:Logo.jpg">
    </body>
</html>

C# Code:

EmailMessage email = new EmailMessage(service);
email.Subject = "Email with Image";
email.Body = new MessageBody(BodyType.HTML, html);
email.ToRecipients.Add("[email protected]");
string file = @"C:\Users\acv\Pictures\Logo.jpg";
email.Attachments.AddFileAttachment("Logo.jpg", file);
email.Attachments[0].IsInline = true;
email.Attachments[0].ContentId = "Logo.jpg";
email.SendAndSaveCopy();

Get filename and path from URI from mediastore

I do this with a one liner:

val bitmap = MediaStore.Images.Media.getBitmap(contentResolver, uri)

Which in the onActivityResult looks like:

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    if (resultCode == Activity.RESULT_OK && requestCode == REQUEST_CODE_IMAGE_PICKER ) {
        data?.data?.let { imgUri: Uri ->
            val bitmap = MediaStore.Images.Media.getBitmap(contentResolver, imgUri)
        }
    }
}

Why is access to the path denied?

I had the exact error when deleting a file. It was a Windows Service running under a Service Account which was unable to delete a .pdf document from a Shared Folder even though it had Full Control of the folder.

What worked for me was navigating to the Security tab of the Shared Folder > Advanced > Share > Add.

I then added the service account to the administrators group, applied the changes and the service account was then able to perform all operations on all files within that folder.

How to set a variable to be "Today's" date in Python/Pandas

pd.datetime.now().strftime("%d/%m/%Y")

this will give output as '11/02/2019'

you can use add time if you want

pd.datetime.now().strftime("%d/%m/%Y %I:%M:%S")

this will give output as '11/02/2019 11:08:26'

strftime formats

Converting date between DD/MM/YYYY and YYYY-MM-DD?

Does anyone else else think it's a waste to convert these strings to date/time objects for what is, in the end, a simple text transformation? If you're certain the incoming dates will be valid, you can just use:

>>> ddmmyyyy = "21/12/2008"
>>> yyyymmdd = ddmmyyyy[6:] + "-" + ddmmyyyy[3:5] + "-" + ddmmyyyy[:2]
>>> yyyymmdd
'2008-12-21'

This will almost certainly be faster than the conversion to and from a date.

How to do an array of hashmaps?

You can't have an array of a generic type. Use List instead.

Get Table and Index storage size in sql server

This query here will list the total size that a table takes up - clustered index, heap and all nonclustered indices:

SELECT 
    s.Name AS SchemaName,
    t.NAME AS TableName,
    p.rows AS RowCounts,
    SUM(a.total_pages) * 8 AS TotalSpaceKB, 
    SUM(a.used_pages) * 8 AS UsedSpaceKB, 
    (SUM(a.total_pages) - SUM(a.used_pages)) * 8 AS UnusedSpaceKB
FROM 
    sys.tables t
INNER JOIN 
    sys.schemas s ON s.schema_id = t.schema_id
INNER JOIN      
    sys.indexes i ON t.OBJECT_ID = i.object_id
INNER JOIN 
    sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
INNER JOIN 
    sys.allocation_units a ON p.partition_id = a.container_id
WHERE 
    t.NAME NOT LIKE 'dt%'    -- filter out system tables for diagramming
    AND t.is_ms_shipped = 0
    AND i.OBJECT_ID > 255 
GROUP BY 
    t.Name, s.Name, p.Rows
ORDER BY 
    s.Name, t.Name

If you want to separate table space from index space, you need to use AND i.index_id IN (0,1) for the table space (index_id = 0 is the heap space, index_id = 1 is the size of the clustered index = data pages) and AND i.index_id > 1 for the index-only space

MSSQL Regular expression

Thank you all for your help.

This is what I have used in the end:

SELECT *, 
  CASE WHEN [url] NOT LIKE '%[^-A-Za-z0-9/.+$]%' 
    THEN 'Valid' 
    ELSE 'No valid' 
  END [Validate]
FROM 
  *table*
  ORDER BY [Validate]

Powershell: count members of a AD group

Every response has missed one detail. What if the group only has 1 user.

$count = @(get-adgroupmember $group).count

Put the command in the @() wrapper so that the result is an array no matter what, so even if it is 1 item, you get a count.

ImportError: cannot import name

Instead of using local imports, you may import the entire module instead of the particular object. Then, in your app module, call mod_login.mod_login

app.py

from flask import Flask
import mod_login

# ...

do_stuff_with(mod_login.mod_login)

mod_login.py

from app import app

mod_login = something

MySQL: update a field only if condition is met

Try this:

UPDATE test
SET
   field = 1
WHERE id = 123 and condition

Pass multiple optional parameters to a C# function

Use a parameter array with the params modifier:

public static int AddUp(params int[] values)
{
    int sum = 0;
    foreach (int value in values)
    {
        sum += value;
    }
    return sum;
}

If you want to make sure there's at least one value (rather than a possibly empty array) then specify that separately:

public static int AddUp(int firstValue, params int[] values)

(Set sum to firstValue to start with in the implementation.)

Note that you should also check the array reference for nullity in the normal way. Within the method, the parameter is a perfectly ordinary array. The parameter array modifier only makes a difference when you call the method. Basically the compiler turns:

int x = AddUp(4, 5, 6);

into something like:

int[] tmp = new int[] { 4, 5, 6 };
int x = AddUp(tmp);

You can call it with a perfectly normal array though - so the latter syntax is valid in source code as well.

Get response from PHP file using AJAX

<script type="text/javascript">
        function returnwasset(){
            alert('return sent');
            $.ajax({
                type: "POST",
                url: "process.php",
                data: somedata;
                dataType:'text'; //or HTML, JSON, etc.
                success: function(response){
                    alert(response);
                    //echo what the server sent back...
                }
            });
        }
    </script>

How can I set an SQL Server connection string?

sa is a system administrator account which comes with SQL Server by default. As you know might already know, you can use two ways to log in to SQL Server.

screen shot of SQL Server Management Studio

Therefore there are connection strings which suitable for each scenario (such as Windows authentication, localdb, etc.). Use SQL Server Connection Strings for ASP.NET Web Applications to build your connection string. These are XML tags. You just need a value of connectionString.

Reversing an Array in Java

Or you could loop through it backeards

int[] firstArray = new int[]{1,2,3,4};
int[] reversedArray = new int[firstArray.length];
int j = 0;
for (int i = firstArray.length -1; i > 0; i--){
    reversedArray[j++] = firstArray[i];
}

(note: I have not compiled this but hopefully it is correct)

How do I print the content of httprequest request?

You can print the request type using:

request.getMethod();

You can print all the headers as mentioned here:

Enumeration<String> headerNames = request.getHeaderNames();
while(headerNames.hasMoreElements()) {
  String headerName = headerNames.nextElement();
  System.out.println("Header Name - " + headerName + ", Value - " + request.getHeader(headerName));
}

To print all the request params, use this:

Enumeration<String> params = request.getParameterNames(); 
while(params.hasMoreElements()){
 String paramName = params.nextElement();
 System.out.println("Parameter Name - "+paramName+", Value - "+request.getParameter(paramName));
}

request is the instance of HttpServletRequest

You can beautify the outputs as you desire.

VueJs get url query

In my case I console.log(this.$route) and returned the fullPath:

console.js:
fullPath: "/solicitud/MX/666",
params: {market: "MX", id: "666"},
path: "/solicitud/MX/666"

console.js: /solicitud/MX/666

How to run Visual Studio post-build events for debug build only

Pre- and Post-Build Events run as a batch script. You can do a conditional statement on $(ConfigurationName).

For instance

if $(ConfigurationName) == Debug xcopy something somewhere

List of strings to one string

I would go with option A:

String.Join(String.Empty, los.ToArray());

My reasoning is because the Join method was written for that purpose. In fact if you look at Reflector, you'll see that unsafe code was used to really optimize it. The other two also WORK, but I think the Join function was written for this purpose, and I would guess, the most efficient. I could be wrong though...

As per @Nuri YILMAZ without .ToArray(), but this is .NET 4+:

String.Join(String.Empty, los);

Option to ignore case with .contains method?

If you are looking for contains & not equals then i would propose below solution. Only drawback is if your searchItem in below solution is "DE" then also it would match

    List<String> list = new ArrayList<>();
    public static final String[] LIST_OF_ELEMENTS = { "ABC", "DEF","GHI" };
    String searchItem= "def";

     if(String.join(",", LIST_OF_ELEMENTS).contains(searchItem.toUpperCase())) {
            System.out.println("found element");
            break;
    }

Emulator in Android Studio doesn't start

I had a similar problem... Android Emulator doesn't open. You need to discover the reason of this... You could run your emulator from the command line. For this you could copy and paste your command line from "Run" or "AVD" Android Studio console. For example:

"{path}\android-sdk\tools\emulator.exe -avd Default_Nexus_5 -netspeed full -netdelay none"

When you launch it from a command line terminal, It give you a message with the error. In my case it was useful for discover the problem:

..\android-sdk\tools>emulator: ERROR: x86 emulation currently requires hardware acceleration! Please ensure Intel HAXM is properly installed and usable. CPU acceleration status: HAX kernel module is not installed!

  • I needed to activate GPU acceleration with a tool to enable it on my machine. I solved it installing from SDK Manager the tool HAXM...

  • I had another problem... For example i had assigned a bad url for skin path of my virtual device... To solve it I have configured my virtual device with a valid skin from my platform sdk: '{path}\android-sdk\platforms\android-{number}\skins{SCREEN_SIZE}'

Now it is opening fine.

Update 8/8/2019:

For newer version of Android SDK, emulator path should be:

"{path}\android-sdk\emulator\emulator.exe"

reference (thank you @CoolMind)

How to update TypeScript to latest version with npm?

Use the command where in prompt to find the current executable in path

C:\> where tsc
C:\Users\user\AppData\Roaming\npm\tsc
C:\Users\user\AppData\Roaming\npm\tsc.cmd

How to form tuple column from two columns in Pandas

Get comfortable with zip. It comes in handy when dealing with column data.

df['new_col'] = list(zip(df.lat, df.long))

It's less complicated and faster than using apply or map. Something like np.dstack is twice as fast as zip, but wouldn't give you tuples.

How to read a large file line by line?

The correct, fully Pythonic way to read a file is the following:

with open(...) as f:
    for line in f:
        # Do something with 'line'

The with statement handles opening and closing the file, including if an exception is raised in the inner block. The for line in f treats the file object f as an iterable, which automatically uses buffered I/O and memory management so you don't have to worry about large files.

There should be one -- and preferably only one -- obvious way to do it.

How do I quickly rename a MySQL database (change schema name)?

I posted this How do I change the database name using MySQL? today after days of head scratching and hair pulling. The solution is quite simple export a schema to a .sql file and open the file and change the database/schema name in the sql CREAT TABLE section at the top. There are three instances or more and may not be at the top of the page if multible schemas are saved to the file. It is posible to edit the entire database this way but I expect that in large databases it could be quite a pain following all instances of a table property or index.

Plotting multiple time series on the same plot using ggplot()

An alternative is to bind the dataframes, and assign them the type of variable they represent. This will let you use the full dataset in a tidier way

library(ggplot2)
library(dplyr)

df1 <- data.frame(dates = 1:10,Variable = rnorm(mean = 0.5,10))
df2 <- data.frame(dates = 1:10,Variable = rnorm(mean = -0.5,10))

df3 <- df1 %>%
  mutate(Type = 'a') %>%
  bind_rows(df2 %>%
              mutate(Type = 'b'))


ggplot(df3,aes(y = Variable,x = dates,color = Type)) + 
  geom_line()

querySelectorAll with multiple conditions

According to the documentation, just like with any css selector, you can specify as many conditions as you want, and they are treated as logical 'OR'.

This example returns a list of all div elements within the document with a class of either "note" or "alert":

var matches = document.querySelectorAll("div.note, div.alert");

source: https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelectorAll

Meanwhile to get the 'AND' functionality you can for example simply use a multiattribute selector, as jquery says:

https://api.jquery.com/multiple-attribute-selector/

ex. "input[id][name$='man']" specifies both id and name of the element and both conditions must be met. For classes it's as obvious as ".class1.class2" to require object of 2 classes.

All possible combinations of both are valid, so you can easily get equivalent of more sophisticated 'OR' and 'AND' expressions.

Compiling C++11 with g++

Flags (or compiler options) are nothing but ordinary command line arguments passed to the compiler executable.

Assuming you are invoking g++ from the command line (terminal):

$ g++ -std=c++11 your_file.cpp -o your_program

or

$ g++ -std=c++0x your_file.cpp -o your_program

if the above doesn't work.

How to parse JSON in Scala using standard Scala classes?

This is the way I do the Scala Parser Combinator Library:

import scala.util.parsing.combinator._
class ImprovedJsonParser extends JavaTokenParsers {

  def obj: Parser[Map[String, Any]] =
    "{" ~> repsep(member, ",") <~ "}" ^^ (Map() ++ _)

  def array: Parser[List[Any]] =
    "[" ~> repsep(value, ",") <~ "]"

  def member: Parser[(String, Any)] =
    stringLiteral ~ ":" ~ value ^^ { case name ~ ":" ~ value => (name, value) }

  def value: Parser[Any] = (
    obj
      | array
      | stringLiteral
      | floatingPointNumber ^^ (_.toDouble)
      |"true"
      |"false"
    )

}
object ImprovedJsonParserTest extends ImprovedJsonParser {
  def main(args: Array[String]) {
    val jsonString =
    """
      {
        "languages": [{
            "name": "English",
            "is_active": true,
            "completeness": 2.5
        }, {
            "name": "Latin",
            "is_active": false,
            "completeness": 0.9
        }]
      }
    """.stripMargin


    val result = parseAll(value, jsonString)
    println(result)

  }
}

How can I check whether a option already exist in select by JQuery

This evaluates to true if it already exists:

$("#yourSelect option[value='yourValue']").length > 0;

how to set mongod --dbpath

For me it must have:

mongod --dbpath=/whatever/data/path

Prevent direct access to a php include file

My answer is somewhat different in approach but includes many of the answers provided here. I would recommend a multipronged approach:

  1. .htaccess and Apache restrictions for sure
  2. defined('_SOMECONSTANT') or die('Hackers! Be gone!');

HOWEVER the defined or die approach has a number of failings. Firstly, it is a real pain in the assumptions to test and debug with. Secondly, it involves horrifyingly, mind-numbingly boring refactoring if you change your mind. "Find and replace!" you say. Yes, but how sure are you that it is written exactly the same everywhere, hmmm? Now multiply that with thousands of files... o.O

And then there's .htaccess. What happens if your code is distributed onto sites where the administrator is not so scrupulous? If you rely only on .htaccess to secure your files you're also going to need a) a backup, b) a box of tissues to dry your tears, c) a fire extinguisher to put out the flames in all the hatemail from people using your code.

So I know the question asks for the "easiest", but I think what this calls for is more "defensive coding".

What I suggest is:

  1. Before any of your scripts require('ifyoulieyougonnadie.php'); (not include() and as a replacement for defined or die)
  2. In ifyoulieyougonnadie.php, do some logic stuff - check for different constants, calling script, localhost testing and such - and then implement your die(), throw new Exception, 403, etc.

    I am creating my own framework with two possible entry points - the main index.php (Joomla framework) and ajaxrouter.php (my framework) - so depending on the point of entry, I check for different things. If the request to ifyoulieyougonnadie.php doesn't come from one of those two files, I know shenanigans are being undertaken!

    But what if I add a new entry point? No worries. I just change ifyoulieyougonnadie.php and I'm sorted, plus no 'find and replace'. Hooray!

    What if I decided to move some of my scripts to do a different framework that doesn't have the same constants defined()? ... Hooray! ^_^

I found this strategy makes development a lot more fun and a lot less:

/**
 * Hmmm... why is my netbeans debugger only showing a blank white page 
 * for this script (that is being tested outside the framework)?
 * Later... I just don't understand why my code is not working...
 * Much later... There are no error messages or anything! 
 * Why is it not working!?!
 * I HATE PHP!!!
 * 
 * Scroll back to the top of my 100s of lines of code...
 * U_U
 *
 * Sorry PHP. I didn't mean what I said. I was just upset.
 */

 // defined('_JEXEC') or die();

 class perfectlyWorkingCode {}

 perfectlyWorkingCode::nowDoingStuffBecauseIRememberedToCommentOutTheDie();

Git - remote: Repository not found

The problem here is windows credentials manager, Please goto control panel and search for credentials manager and delete all contents of it regarding github

How do you perform wireless debugging in Xcode 9 with iOS 11, Apple TV 4K, etc?

You can open Xcode Help -> Run and debug -> Network debugging for more info. Hope it helps.

How can I create a unique constraint on my column (SQL Server 2008 R2)?

Set column as unique in SQL Server from the GUI:

They really make you run around the barn to do it with the GUI:

Make sure your column does not violate the unique constraint before you begin.

  1. Open SQL Server Management Studio.
  2. Right click your Table, click "Design".
  3. Right click the column you want to edit, a popup menu appears, click Indexes/Keys.
  4. Click the "Add" Button.
  5. Expand the "General" tab.
  6. Make sure you have the column you want to make unique selected in the "columns" box.
  7. Change the "Type" box to "Unique Key".
  8. Click "Close".
  9. You see a little asterisk in the file window, this means changes are not yet saved.
  10. Press Save or hit Ctrl+s. It should save, and your column should be unique.

Or set column as unique from the SQL Query window:

alter table location_key drop constraint pinky;
alter table your_table add constraint pinky unique(yourcolumn);

Changes take effect immediately:

Command(s) completed successfully.

How can I change image tintColor in iOS and WatchKit

There is a native method for UIImage since iOS 13

let image = yourImage.withTintColor(.systemRed)

How can I set the background color of <option> in a <select> element?

I had this problem too. I found setting the appearance to none helped.

.class {
    appearance:none;
    -moz-appearance:none;
    -webkit-appearance:none;

    background-color: red;
}

Get the client's IP address in socket.io

Here's how to get your client's ip address (v 3.1.0):


// Current Client
const ip = socket.handshake.headers["x-forwarded-for"].split(",")[1].toString().substring(1, this.length);
// Server 
const ip2 = socket.handshake.headers["x-forwarded-for"].split(",")[0].toString();

And just to check if it works go to geoplugin.net/json.gsp?ip= just make sure to switch the ip in the link. After you have done that it should give you the accurate location of the client which means that it worked.

How to generate the whole database script in MySQL Workbench?

None of these worked for me. I'm using Mac OS 10.10.5 and Workbench 6.3. What worked for me is Database->Migration Wizard... Flow the steps very carefully

click() event is calling twice in jquery

I faced this issue because my $(elem).click(function(){}); script was placed inline in a div that was set to style="display:none;".

When the css display was switched to block, the script would add the event listener a second time. I moved the script to a separate .js file and the duplicate event listener was no longer initiated.

What is &#39; and why does Google search replace it with apostrophe?

It's HTML character references for encoding a character by its decimal code point

Look at the ASCII table here and you'll see that 39 (hex 0x27, octal 47) is the code for apostrophe

ASCII table

How to get a resource id with a known resource name?

in addition to @lonkly solution

  1. see reflections and field accessibility
  2. unnecessary variables

method:

/**
 * lookup a resource id by field name in static R.class 
 * 
 * @author - ceph3us
 * @param variableName - name of drawable, e.g R.drawable.<b>image</b>
 * @param ?            - class of resource, e.g R.drawable.class or R.raw.class
 * @return integer id of resource
 */
public static int getResId(String variableName, Class<?> ?)
                     throws android.content.res.Resources.NotFoundException {
    try {
        // lookup field in class 
        java.lang.reflect.Field field = ?.getField(variableName);
        // always set access when using reflections  
        // preventing IllegalAccessException   
        field.setAccessible(true);
        // we can use here also Field.get() and do a cast 
        // receiver reference is null as it's static field 
        return field.getInt(null);
    } catch (Exception e) {
        // rethrow as not found ex
        throw new Resources.NotFoundException(e.getMessage());
    }
}

Remove duplicate values from JS array

Vanilla JS solutions with complexity of O(n) (fastest possible for this problem). Modify the hashFunction to distinguish the objects (e.g. 1 and "1") if needed. The first solution avoids hidden loops (common in functions provided by Array).

var dedupe = function(a) 
{
    var hash={},ret=[];
    var hashFunction = function(v) { return ""+v; };
    var collect = function(h)
    {
        if(hash.hasOwnProperty(hashFunction(h)) == false) // O(1)
        {
            hash[hashFunction(h)]=1;
            ret.push(h); // should be O(1) for Arrays
            return;
        }
    };

    for(var i=0; i<a.length; i++) // this is a loop: O(n)
        collect(a[i]);
    //OR: a.forEach(collect); // this is a loop: O(n)

    return ret;
}

var dedupe = function(a) 
{
    var hash={};
    var isdupe = function(h)
    {
        if(hash.hasOwnProperty(h) == false) // O(1)
        {
            hash[h]=1;
            return true;
        }

        return false;
    };

    return a.filter(isdupe); // this is a loop: O(n)
}

List of ANSI color escape sequences

For these who don't get proper results other than mentioned languages, if you're using C# to print a text into console(terminal) window you should replace "\033" with "\x1b". In Visual Basic it would be Chrw(27).

Regex for numbers only

Sorry for ugly formatting. For any number of digits:

[0-9]*

For one or more digit:

[0-9]+

jQuery/JavaScript: accessing contents of an iframe

I prefer to use other variant for accessing. From parent you can have a access to variable in child iframe. $ is a variable too and you can receive access to its just call window.iframe_id.$

For example, window.view.$('div').hide() - hide all divs in iframe with id 'view'

But, it doesn't work in FF. For better compatibility you should use

$('#iframe_id')[0].contentWindow.$

sudo: npm: command not found

If you have downloaded node package and extracted somewhere like /opt you can simply create symbolic link inside /usr/local/bin.

/usr/local/bin/npm -> /opt/node-v4.6.0-linux-x64/bin/npm
/usr/local/bin/node -> /opt/node-v4.6.0-linux-x64/bin/node

How do I join two lines in vi?

Vi or Vim?

Anyway, the following command works for Vim in 'nocompatible' mode. That is, I suppose, almost pure vi.

:join!

If you want to do it from normal command use

gJ

With 'gJ' you join lines as is -- without adding or removing whitespaces:

S<Switch_ID>_F<File type>
_ID<ID number>_T<date+time>_O<Original File name>.DAT

Result:

S<Switch_ID>_F<File type>_ID<ID number>_T<date+time>_O<Original File name>.DAT

With 'J' command you will have:

S<Switch_ID>_F<File type> _ID<ID number>_T<date+time>_O<Original File name>.DAT

Note space between type> and _ID.

SQLite3 database or disk is full / the database disk image is malformed

Cloning the current database from the sqlite3 commandline worked for me.

.open /path/to/database/corrupted_database.sqlite3
.clone /path/to/database/new_database.sqlite3

In the Django setting file change the database name

DATABASES = {
'default': {
    'ENGINE': 'django.db.backends.sqlite3',
    'NAME': os.path.join(BASE_DIR, 'new_database.sqlite3'),
}}

Converting HTML to Excel?

We copy/paste html pages from our ERP to Excel using "paste special.. as html/unicode" and it works quite well with tables.

Doing a cleanup action just before Node.js exits

Just wanted to mention death package here: https://github.com/jprichardson/node-death

Example:

var ON_DEATH = require('death')({uncaughtException: true}); //this is intentionally ugly

ON_DEATH(function(signal, err) {
  //clean up code here
})

Make a URL-encoded POST request using `http.NewRequest(...)`

URL-encoded payload must be provided on the body parameter of the http.NewRequest(method, urlStr string, body io.Reader) method, as a type that implements io.Reader interface.

Based on the sample code:

package main

import (
    "fmt"
    "net/http"
    "net/url"
    "strconv"
    "strings"
)

func main() {
    apiUrl := "https://api.com"
    resource := "/user/"
    data := url.Values{}
    data.Set("name", "foo")
    data.Set("surname", "bar")

    u, _ := url.ParseRequestURI(apiUrl)
    u.Path = resource
    urlStr := u.String() // "https://api.com/user/"

    client := &http.Client{}
    r, _ := http.NewRequest(http.MethodPost, urlStr, strings.NewReader(data.Encode())) // URL-encoded payload
    r.Header.Add("Authorization", "auth_token=\"XXXXXXX\"")
    r.Header.Add("Content-Type", "application/x-www-form-urlencoded")
    r.Header.Add("Content-Length", strconv.Itoa(len(data.Encode())))

    resp, _ := client.Do(r)
    fmt.Println(resp.Status)
}

resp.Status is 200 OK this way.

PreparedStatement IN clause alternatives?

This worked for me (psuedocode):

public class SqlHelper
{
    public static final ArrayList<String>platformList = new ArrayList<>(Arrays.asList("iOS","Android","Windows","Mac"));

    public static final String testQuery = "select * from devices where platform_nm in (:PLATFORM_NAME)";
}

specicify binding :

public class Test extends NamedParameterJdbcDaoSupport
public List<SampleModelClass> runQuery()
{
    //define rowMapper to insert in object of SampleClass
    final Map<String,Object> map = new HashMap<>();
    map.put("PLATFORM_LIST",DeviceDataSyncQueryConstants.platformList);
    return getNamedParameterJdbcTemplate().query(SqlHelper.testQuery, map, rowMapper)
}

Solutions for INSERT OR UPDATE on SQL Server

That depends on the usage pattern. One has to look at the usage big picture without getting lost in the details. For example, if the usage pattern is 99% updates after the record has been created, then the 'UPSERT' is the best solution.

After the first insert (hit), it will be all single statement updates, no ifs or buts. The 'where' condition on the insert is necessary otherwise it will insert duplicates, and you don't want to deal with locking.

UPDATE <tableName> SET <field>=@field WHERE key=@key;

IF @@ROWCOUNT = 0
BEGIN
   INSERT INTO <tableName> (field)
   SELECT @field
   WHERE NOT EXISTS (select * from tableName where key = @key);
END

C++ Boost: undefined reference to boost::system::generic_category()

You could come across another problem. After installing Boost on the Linux Mint I've had the same problem. Linking -lboost_system or -lboost_system-mt haven't worked because library have had name libboost_system.so.1.54.0.

So the solution is to create symbolic link to the original file. In my case

sudo ln -s /usr/lib/x86_64-linux-gnu/libboost_system.so.1.54.0 /usr/lib/libboost_system.so

For more information see this question.

How to store image in SQL Server database tables column

give this a try,

insert into tableName (ImageColumn) 
SELECT BulkColumn 
FROM Openrowset( Bulk 'image..Path..here', Single_Blob) as img

INSERTING

enter image description here

REFRESHING THE TABLE

enter image description here

Reactjs: Unexpected token '<' Error

I just started learning React today and was facing the same problem. Below is the code I had written.

<script type="text/babel">
    class Hello extends React.Component {
        render(){
            return (
                <div>
                    <h1>Hello World</h1>
                </div>
            )
        }
    }
    ReactDOM.render(
        <Hello/>
        document.getElementById('react-container')
    )


</script>

And as you can see that I had missed a comma (,) after I use <Hello/>. And error itself is saying on which line we need to look.

enter image description here

So once I add a comma before the second parameter for the ReactDOM.render() function, all started working fine.

How to open a workbook specifying its path

You can also open a required file through a prompt, This helps when you want to select file from different path and different file.

Sub openwb()
Dim wkbk As Workbook
Dim NewFile As Variant

NewFile = Application.GetOpenFilename("microsoft excel files (*.xlsm*), *.xlsm*")

If NewFile <> False Then
Set wkbk = Workbooks.Open(NewFile)
End If
End Sub

When to use .First and when to use .FirstOrDefault with LINQ?

linq many ways to implement single simple query on collections, just we write joins in sql, a filter can be applied first or last depending on the need and necessity.

Here is an example where we can find an element with a id in a collection. To add more on this, methods First, FirstOrDefault, would ideally return same when a collection has at least one record. If, however, a collection is okay to be empty. then First will return an exception but FirstOrDefault will return null or default. For instance, int will return 0. Thus usage of such is although said to be personal preference, but its better to use FirstOrDefault to avoid exception handling. here is an example where, we run over a collection of transactionlist

java.lang.ClassNotFoundException: com.sun.jersey.spi.container.servlet.ServletContainer

If you are using jersey 2.x then you need different configuration in web.xml as servlet class is change in it. you can update your web.xml with following configuration.

    <servlet>
    <servlet-name>myrest</servlet-name>
    <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>    
    <init-param>
      <param-name>jersey.config.server.provider.packages</param-name>
      <param-value>your.package.path</param-value>
    </init-param>
    <init-param>
     <param-name>unit:WidgetPU</param-name>
     <param-value>persistence/widget</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>myrest</servlet-name>
    <url-pattern>/rest/*</url-pattern>
  </servlet-mapping>

How do I link to Google Maps with a particular longitude and latitude?

The best way is to use q parameter so that it displays the map with the point marked. eg.:

https://maps.google.com/?q=<lat>,<lng>

Spring Data JPA findOne() change to Optional how to use this?

I always write a default method "findByIdOrError" in widely used CrudRepository repos/interfaces.

@Repository 
public interface RequestRepository extends CrudRepository<Request, Integer> {

    default Request findByIdOrError(Integer id) {
        return findById(id).orElseThrow(EntityNotFoundException::new);
    } 
}

When should one use a spinlock instead of mutex?

The rule for using spinlocks is simple: use a spinlock if and only if the real time the lock is held is bounded and sufficiently small.

Note that usually user implemented spinlocks DO NOT satisfy this requirement because they do not disable interrupts. Unless pre-emptions are disabled, a pre-emption whilst a spinlock is held violates the bounded time requirement.

Sufficiently small is a judgement call and depends on the context.

Exception: some kernel programming must use a spinlock even when the time is not bounded. In particular if a CPU has no work to do, it has no choice but to spin until some more work turns up.

Special danger: in low level programming take great care when multiple interrupt priorities exist (usually there is at least one non-maskable interrupt). In this higher priority pre-emptions can run even if interrupts at the thread priority are disabled (such as priority hardware services, often related to the virtual memory management). Provided a strict priority separation is maintained, the condition for bounded real time must be relaxed and replaced with bounded system time at that priority level. Note in this case not only can the lock holder be pre-empted but the spinner can also be interrupted; this is generally not a problem because there's nothing you can do about it.

How to append one file to another in Linux from the shell?

You can also do this without cat, though honestly cat is more readable:

>> file1 < file2

The >> appends STDIN to file1 and the < dumps file2 to STDIN.

How to watch and compile all TypeScript sources?

you can watch all files like this

tsc *.ts --watch

Getting the IP address of the current machine using Java

You can use java.net.InetAddress API. Try this :

InetAddress.getLocalHost().getHostAddress();

Find position of a node using xpath

Just a note to the answer done by James Sulak.

If you want to take into consideration that the node may not exist and want to keep it purely XPATH, then try the following that will return 0 if the node does not exist.

count(a/b[.='tsr']/preceding-sibling::*)+number(boolean(a/b[.='tsr']))

How would one write object-oriented code in C?

Check out GObject. It's meant to be OO in C and one implementation of what you're looking for. If you really want OO though, go with C++ or some other OOP language. GObject can be really tough to work with at times if you're used to dealing with OO languages, but like anything, you'll get used to the conventions and flow.

Deserializing JSON data to C# using JSON.NET

Use

var rootObject =  JsonConvert.DeserializeObject<RootObject>(string json);

Create your classes on JSON 2 C#


Json.NET documentation: Serializing and Deserializing JSON with Json.NET

What's the difference between compiled and interpreted language?

A compiler, in general, reads higher level language computer code and converts it to either p-code or native machine code. An interpreter runs directly from p-code or an interpreted code such as Basic or Lisp. Typically, compiled code runs much faster, is more compact, and has already found all of the syntax errors and many of the illegal reference errors. Interpreted code only finds such errors after the application attempts to interpret the affected code. Interpreted code is often good for simple applications that will only be used once or at most a couple times, or maybe even for prototyping. Compiled code is better for serious applications. A compiler first takes in the entire program, checks for errors, compiles it and then executes it. Whereas, an interpreter does this line by line, so it takes one line, checks it for errors, and then executes it.

If you need more information, just Google for "difference between compiler and interpreter".

Eclipse : Failed to connect to remote VM. Connection refused.

Which server are you using?

Like already said:

  1. In your debug configuration you'll have to define the right port of your server (GF:9009 / Tomcat:8000)
  2. You'll have to set the JVM property of the server to debug

For Glassfish:

    Log in to admin-console > Configurations > server-config > JVM-Settings > check DEBUG checkbox > restart server

For Tomcat:

create file debug.bat/.sh (depending on your OS) in %TOMCAT_HOME%/bin directory and write

    set JPDA_ADDRESS=8000
    set JPDA_TRANSPORT=dt_socket
    catalina.bat jpda start

in it.

After you've created this file start server by executing debug.bat/.sh.

Now you should be able to debug remotely in Eclipse after you set the necessary properties in your debug configuration.

Hope this helped! Have Fun!

EDIT

If you're running tomcat in a Win environment as a service you don't have a catalina.bat file in the bin-directory of your tomcat installation.
To set your server into debug-mode please try the following:

  1. Run the Configuration option in Windows Menu or run %catalina_home%/bin/tomcat6w.exe
  2. In Java tab, add this line to Java:

options:-Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=n

PL/SQL ORA-01422: exact fetch returns more than requested number of rows

A SELECT INTO statement will throw an error if it returns anything other than 1 row. If it returns 0 rows, you'll get a no_data_found exception. If it returns more than 1 row, you'll get a too_many_rows exception. Unless you know that there will always be exactly 1 employee with a salary greater than 3000, you do not want a SELECT INTO statement here.

Most likely, you want to use a cursor to iterate over (potentially) multiple rows of data (I'm also assuming that you intended to do a proper join between the two tables rather than doing a Cartesian product so I'm assuming that there is a departmentID column in both tables)

BEGIN
  FOR rec IN (SELECT EMPLOYEE.EMPID, 
                     EMPLOYEE.ENAME, 
                     EMPLOYEE.DESIGNATION, 
                     EMPLOYEE.SALARY,  
                     DEPARTMENT.DEPT_NAME 
                FROM EMPLOYEE, 
                     DEPARTMENT 
               WHERE employee.departmentID = department.departmentID
                 AND EMPLOYEE.SALARY > 3000)
  LOOP
    DBMS_OUTPUT.PUT_LINE ('Employee Nnumber: ' || rec.EMPID);
    DBMS_OUTPUT.PUT_LINE ('---------------------------------------------------');
    DBMS_OUTPUT.PUT_LINE ('Employee Name: ' || rec.ENAME);
    DBMS_OUTPUT.PUT_LINE ('---------------------------------------------------');
    DBMS_OUTPUT.PUT_LINE ('Employee Designation: ' || rec.DESIGNATION);
    DBMS_OUTPUT.PUT_LINE ('----------------------------------------------------');
    DBMS_OUTPUT.PUT_LINE ('Employee Salary: ' || rec.SALARY);
    DBMS_OUTPUT.PUT_LINE ('----------------------------------------------------');
    DBMS_OUTPUT.PUT_LINE ('Employee Department: ' || rec.DEPT_NAME);
  END LOOP;
END;

I'm assuming that you are just learning PL/SQL as well. In real code, you'd never use dbms_output like this and would not depend on anyone seeing data that you write to the dbms_output buffer.

Check if two unordered lists are equal

What about getting the string representation of the lists and comparing them ?

>>> l1 = ['one', 'two', 'three']
>>> l2 = ['one', 'two', 'three']
>>> l3 = ['one', 'three', 'two']
>>> print str(l1) == str(l2)
True
>>> print str(l1) == str(l3)
False

Automatically set appsettings.json for dev and release environments in asp.net core?

You can make use of environment variables and the ConfigurationBuilder class in your Startup constructor like this:

public Startup(IHostingEnvironment env)
{
    var builder = new ConfigurationBuilder()
    .SetBasePath(env.ContentRootPath)
    .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
    .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
    .AddEnvironmentVariables();
    this.configuration = builder.Build();
}

Then you create an appsettings.xxx.json file for every environment you need, with "xxx" being the environment name. Note that you can put all global configuration values in your "normal" appsettings.json file and only put the environment specific stuff into these new files.

Now you only need an environment variable called ASPNETCORE_ENVIRONMENT with some specific environment value ("live", "staging", "production", whatever). You can specify this variable in your project settings for your development environment, and of course you need to set it in your staging and production environments also. The way you do it there depends on what kind of environment this is.

UPDATE: I just realized you want to choose the appsettings.xxx.json based on your current build configuration. This cannot be achieved with my proposed solution and I don't know if there is a way to do this. The "environment variable" way, however, works and might as well be a good alternative to your approach.

What is the standard Python docstring format?

I suggest using Vladimir Keleshev's pep257 Python program to check your docstrings against PEP-257 and the Numpy Docstring Standard for describing parameters, returns, etc.

pep257 will report divergence you make from the standard and is called like pylint and pep8.

Eloquent get only one column as an array

I think you can achieve it by using the below code

Model::get(['ColumnName'])->toArray();

Auto Generate Database Diagram MySQL

Try out Vertabelo!

It's an online database modeler that supports reverse enginnering.

Just create free of charge Vertabelo account, import an existing database into Vertabelo and voila - your database is in Vertabelo!

It supports following databases:

  • PostgreSQL,
  • MySQL,
  • Oracle,
  • IBM DB2,
  • HSQLDB,
  • MS SQL Server.

Cannot stop or restart a docker container

Enjoy

sudo aa-remove-unknown

This is what worked for me.

<SELECT multiple> - how to allow only one item selected?

<select name="flowers" size="5" style="height:200px">
 <option value="1">Rose</option>
 <option value="2">Tulip</option>
</select>

This simple solution allows to obtain visually a list of options, but to be able to select only one.

Order a MySQL table by two columns

This maybe help somebody who is looking for the way to sort table by two columns, but in paralel way. This means to combine two sorts using aggregate sorting function. It's very useful when for example retrieving articles using fulltext search and also concerning the article publish date.

This is only example, but if you catch the idea you can find a lot of aggregate functions to use. You can even weight the columns to prefer one over second. The function of mine takes extremes from both sorts, thus the most valued rows are on the top.

Sorry if there exists simplier solutions to do this job, but I haven't found any.

SELECT
 `id`,
 `text`,
 `date`
 FROM
   (
   SELECT
     k.`id`,
     k.`text`,
     k.`date`,
     k.`match_order_id`,
     @row := @row + 1 as `date_order_id`
     FROM
     (
       SELECT
         t.`id`,
         t.`text`,
         t.`date`,
         @row := @row + 1 as `match_order_id`
         FROM
         (
           SELECT
             `art_id` AS `id`,
             `text`   AS `text`,
             `date`   AS `date`,
             MATCH (`text`) AGAINST (:string) AS `match`
             FROM int_art_fulltext
             WHERE MATCH (`text`) AGAINST (:string IN BOOLEAN MODE)
             LIMIT 0,101
         ) t,
         (
           SELECT @row := 0
         ) r
         ORDER BY `match` DESC
     ) k,
     (
       SELECT @row := 0
     ) l
     ORDER BY k.`date` DESC
   ) s
 ORDER BY (1/`match_order_id`+1/`date_order_id`) DESC

equivalent of vbCrLf in c#

"FirstLine" + "<br/>" "SecondLine"

How can I trim beginning and ending double quotes from a string?

To remove the first character and last character from the string, use:

myString = myString.substring(1, myString.length()-1);

Why isn't my Pandas 'apply' function referencing multiple columns working?

If you just want to compute (column a) % (column b), you don't need apply, just do it directly:

In [7]: df['a'] % df['c']                                                                                                                                                        
Out[7]: 
0   -1.132022                                                                                                                                                                    
1   -0.939493                                                                                                                                                                    
2    0.201931                                                                                                                                                                    
3    0.511374                                                                                                                                                                    
4   -0.694647                                                                                                                                                                    
5   -0.023486                                                                                                                                                                    
Name: a

How do you get assembler output from C/C++ source in gcc?

Well, as everyone said, use -S option. If you use -save-temps option, you can also get preprocessed file(.i), assembly file(.s) and object file(*.o). (get each of them by using -E, -S, and -c.)

How to convert Map keys to array?

Array.from(myMap.keys()) does not work in google application scripts.

Trying to use it results in the error TypeError: Cannot find function from in object function Array() { [native code for Array.Array, arity=1] }.

To get a list of keys in GAS do this:

var keysList = Object.keys(myMap);

How do I scroll the UIScrollView when the keyboard appears?

The recommended way from Apple is to change the contentInset of the UIScrollView. It is a very elegant solution, because you do not have to mess with the contentSize. Following code is copied from the Keyboard Programming Guide, where the handling of this issue is explained. You should have a look into it.

// Call this method somewhere in your view controller setup code.
- (void)registerForKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self
            selector:@selector(keyboardWasShown:)
            name:UIKeyboardDidShowNotification object:nil];
   [[NSNotificationCenter defaultCenter] addObserver:self
             selector:@selector(keyboardWillBeHidden:)
             name:UIKeyboardWillHideNotification object:nil];
}

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWasShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
    scrollView.contentInset = contentInsets;
    scrollView.scrollIndicatorInsets = contentInsets;

    // If active text field is hidden by keyboard, scroll it so it's visible
    // Your application might not need or want this behavior.
    CGRect aRect = self.view.frame;
    aRect.size.height -= kbSize.height;
    if (!CGRectContainsPoint(aRect, activeField.frame.origin) ) {
        CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y-kbSize.height);
        [scrollView setContentOffset:scrollPoint animated:YES];
    }
}

// Called when the UIKeyboardWillHideNotification is sent    
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    scrollView.contentInset = contentInsets;
    scrollView.scrollIndicatorInsets = contentInsets;
}

Swift version:

func registerForKeyboardNotifications() {
    NotificationCenter.default.addObserver(self, selector: #selector(onKeyboardAppear(_:)), name: NSNotification.Name.UIKeyboardDidShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(onKeyboardDisappear(_:)), name: NSNotification.Name.UIKeyboardDidHide, object: nil)
}

// Don't forget to unregister when done
deinit {
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardDidShow, object: nil)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardDidHide, object: nil)
}

@objc func onKeyboardAppear(_ notification: NSNotification) {
    let info = notification.userInfo!
    let rect: CGRect = info[UIKeyboardFrameBeginUserInfoKey] as! CGRect
    let kbSize = rect.size

    let insets = UIEdgeInsetsMake(0, 0, kbSize.height, 0)
    scrollView.contentInset = insets
    scrollView.scrollIndicatorInsets = insets

    // If active text field is hidden by keyboard, scroll it so it's visible
    // Your application might not need or want this behavior.
    var aRect = self.view.frame;
    aRect.size.height -= kbSize.height;

    let activeField: UITextField? = [addressTextView, servicePathTextView, usernameTextView, passwordTextView].first { $0.isFirstResponder }
    if let activeField = activeField {
        if !aRect.contains(activeField.frame.origin) {
            let scrollPoint = CGPoint(x: 0, y: activeField.frame.origin.y-kbSize.height)
            scrollView.setContentOffset(scrollPoint, animated: true)
        }
    }
}

@objc func onKeyboardDisappear(_ notification: NSNotification) {
    scrollView.contentInset = UIEdgeInsets.zero
    scrollView.scrollIndicatorInsets = UIEdgeInsets.zero
}

Removing header column from pandas dataframe

I had the same problem but solved it in this way:

df = pd.read_csv('your-array.csv', skiprows=[0])

LDAP root query syntax to search more than one specific OU

I don't think this is possible with AD. The distinguishedName attribute is the only thing I know of that contains the OU piece on which you're trying to search, so you'd need a wildcard to get results for objects under those OUs. Unfortunately, the wildcard character isn't supported on DNs.

If at all possible, I'd really look at doing this in 2 queries using OU=Staff... and OU=Vendors... as the base DNs.

Skip a submodule during a Maven build

Maven version 3.2.1 added this feature, you can use the -pl switch (shortcut for --projects list) with ! or - (source) to exclude certain submodules.

mvn -pl '!submodule-to-exclude' install
mvn -pl -submodule-to-exclude install

Be careful in bash the character ! is a special character, so you either have to single quote it (like I did) or escape it with the backslash character.

The syntax to exclude multiple module is the same as the inclusion

mvn -pl '!submodule1,!submodule2' install
mvn -pl -submodule1,-submodule2 install

EDIT Windows does not seem to like the single quotes, but it is necessary in bash ; in Windows, use double quotes (thanks @awilkinson)

mvn -pl "!submodule1,!submodule2" install

Pass a password to ssh in pure bash

Since there were no exact answers to my question, I made some investigation why my code doesn't work when there are other solutions that works, and decided to post what I found to complete the subject.
As it turns out:

"ssh uses direct TTY access to make sure that the password is indeed issued by an interactive keyboard user." sshpass manpage

which answers the question, why the pipes don't work in this case. The obvious solution was to create conditions so that ssh "thought" that it is run in the regular terminal and since it may be accomplished by simple posix functions, it is beyond what simple bash offers.

Android custom Row Item for ListView

you can follow BaseAdapter and create your custome Xml file and bind it with you BaseAdpter and populate it with Listview see here need to change xml file as Require.

How to add multiple columns to pandas dataframe in one assignment?

I would have expected your syntax to work too. The problem arises because when you create new columns with the column-list syntax (df[[new1, new2]] = ...), pandas requires that the right hand side be a DataFrame (note that it doesn't actually matter if the columns of the DataFrame have the same names as the columns you are creating).

Your syntax works fine for assigning scalar values to existing columns, and pandas is also happy to assign scalar values to a new column using the single-column syntax (df[new1] = ...). So the solution is either to convert this into several single-column assignments, or create a suitable DataFrame for the right-hand side.

Here are several approaches that will work:

import pandas as pd
import numpy as np

df = pd.DataFrame({
    'col_1': [0, 1, 2, 3],
    'col_2': [4, 5, 6, 7]
})

Then one of the following:

1) Three assignments in one, using list unpacking:

df['column_new_1'], df['column_new_2'], df['column_new_3'] = [np.nan, 'dogs', 3]

2) DataFrame conveniently expands a single row to match the index, so you can do this:

df[['column_new_1', 'column_new_2', 'column_new_3']] = pd.DataFrame([[np.nan, 'dogs', 3]], index=df.index)

3) Make a temporary data frame with new columns, then combine with the original data frame later:

df = pd.concat(
    [
        df,
        pd.DataFrame(
            [[np.nan, 'dogs', 3]], 
            index=df.index, 
            columns=['column_new_1', 'column_new_2', 'column_new_3']
        )
    ], axis=1
)

4) Similar to the previous, but using join instead of concat (may be less efficient):

df = df.join(pd.DataFrame(
    [[np.nan, 'dogs', 3]], 
    index=df.index, 
    columns=['column_new_1', 'column_new_2', 'column_new_3']
))

5) Using a dict is a more "natural" way to create the new data frame than the previous two, but the new columns will be sorted alphabetically (at least before Python 3.6 or 3.7):

df = df.join(pd.DataFrame(
    {
        'column_new_1': np.nan,
        'column_new_2': 'dogs',
        'column_new_3': 3
    }, index=df.index
))

6) Use .assign() with multiple column arguments.

I like this variant on @zero's answer a lot, but like the previous one, the new columns will always be sorted alphabetically, at least with early versions of Python:

df = df.assign(column_new_1=np.nan, column_new_2='dogs', column_new_3=3)

7) This is interesting (based on https://stackoverflow.com/a/44951376/3830997), but I don't know when it would be worth the trouble:

new_cols = ['column_new_1', 'column_new_2', 'column_new_3']
new_vals = [np.nan, 'dogs', 3]
df = df.reindex(columns=df.columns.tolist() + new_cols)   # add empty cols
df[new_cols] = new_vals  # multi-column assignment works for existing cols

8) In the end it's hard to beat three separate assignments:

df['column_new_1'] = np.nan
df['column_new_2'] = 'dogs'
df['column_new_3'] = 3

Note: many of these options have already been covered in other answers: Add multiple columns to DataFrame and set them equal to an existing column, Is it possible to add several columns at once to a pandas DataFrame?, Add multiple empty columns to pandas DataFrame

Java Scanner String input

use this to clear the previous keyboard buffer before scanning the string it will solve your problem scanner.nextLine();//this is to clear the keyboard buffer

What is the default font of Sublime Text?

Yes. You can use Console of Sublime with (Linux):

Ctrl + `

And type:

view.settings().get('font_face')

Get any setting the same way.

How is the java memory pool divided?

Heap memory

The heap memory is the runtime data area from which the Java VM allocates memory for all class instances and arrays. The heap may be of a fixed or variable size. The garbage collector is an automatic memory management system that reclaims heap memory for objects.

  • Eden Space: The pool from which memory is initially allocated for most objects.

  • Survivor Space: The pool containing objects that have survived the garbage collection of the Eden space.

  • Tenured Generation or Old Gen: The pool containing objects that have existed for some time in the survivor space.

Non-heap memory

Non-heap memory includes a method area shared among all threads and memory required for the internal processing or optimization for the Java VM. It stores per-class structures such as a runtime constant pool, field and method data, and the code for methods and constructors. The method area is logically part of the heap but, depending on the implementation, a Java VM may not garbage collect or compact it. Like the heap memory, the method area may be of a fixed or variable size. The memory for the method area does not need to be contiguous.

  • Permanent Generation: The pool containing all the reflective data of the virtual machine itself, such as class and method objects. With Java VMs that use class data sharing, this generation is divided into read-only and read-write areas.

  • Code Cache: The HotSpot Java VM also includes a code cache, containing memory that is used for compilation and storage of native code.

Here's some documentation on how to use Jconsole.

Not able to change TextField Border Color

That is not changing due to the default theme set to the screen.

So just change them for the widget you are drawing by wrapping your TextField with new ThemeData()

child: new Theme(
          data: new ThemeData(
            primaryColor: Colors.redAccent,
            primaryColorDark: Colors.red,
          ),
          child: new TextField(
            decoration: new InputDecoration(
                border: new OutlineInputBorder(
                    borderSide: new BorderSide(color: Colors.teal)),
                hintText: 'Tell us about yourself',
                helperText: 'Keep it short, this is just a demo.',
                labelText: 'Life story',
                prefixIcon: const Icon(
                  Icons.person,
                  color: Colors.green,
                ),
                prefixText: ' ',
                suffixText: 'USD',
                suffixStyle: const TextStyle(color: Colors.green)),
          ),
        ));

enter image description here

How do I remove the old history from a git repository?

I needed to read several answers and some other info to understand what I was doing.

1. Ignore everything older than a certain commit

The file .git/info/grafts can define fake parents for a commit. A line with just a commit id, says that the commit doesn't have a parent. If we wanted to say that we care only about the last 2000 commits, we can type:

git rev-parse HEAD~2000 > .git/info/grafts

git rev-parse gives us the commit id of the 2000th parent of the current commit. The above command will overwrite the grafts file if present. Check if it's there first.

2. Rewrite the Git history (optional)

If you want to make this grafted fake parent a real one, then run:

git filter-branch -- --all

It will change all commit ids. Every copy of this repository needs to be updated forcefully.

3. Clean up disk space

I didn't done step 2, because I wanted my copy to stay compatible with the upstream. I just wanted to save some disk space. In order to forget all the old commits:

git prune
git gc

Alternative: shallow copies

If you have a shallow copy of another repository and just want to save some disk space, you can update .git/shallow. But be careful that nothing is pointing at a commit from before. So you could run something like this:

git fetch --prune
git rev-parse HEAD~2000 > .git/shallow
git prune
git gc

The entry in shallow works like a graft. But be careful not to use grafts and shallow at the same time. At least, don't have the same entries in there, it will fail.

If you still have some old references (tags, branches, remote heads) that point to older commits, they won't be cleaned up and you won't save more disk space.

How to do a SUM() inside a case statement in SQL server

You could use a Common Table Expression to create the SUM first, join it to the table, and then use the WHEN to to get the value from the CTE or the original table as necessary.

WITH PercentageOfTotal (Id, Percentage) 
AS 
(
    SELECT Id, (cnt / SUM(AreaId)) FROM dbo.MyTable GROUP BY Id
)
SELECT 
    CASE
        WHEN o.TotalType = 'Average' THEN r.avgscore
        WHEN o.TotalType = 'PercentOfTot' THEN pt.Percentage
        ELSE o.cnt
    END AS [displayscore]
FROM PercentageOfTotal pt
    JOIN dbo.MyTable t ON pt.Id = t.Id

How do I query between two dates using MySQL?

Is date_field of type datetime? Also you need to put the eariler date first.

It should be:

SELECT * FROM `objects` 
WHERE  (date_field BETWEEN '2010-01-30 14:15:55' AND '2010-09-29 10:15:55')

Right HTTP status code to wrong input

409 Conflict could be an acceptable solution.

According to: https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html

The request could not be completed due to a conflict with the current state of the resource. This code is only allowed in situations where it is expected that the user might be able to resolve the conflict and resubmit the request. The response body SHOULD include enough information for the user to recognize the source of the conflict. Ideally, the response entity would include enough information for the user or user agent to fix the problem; however, that might not be possible and is not required.

The doc continues with an example:

Conflicts are most likely to occur in response to a PUT request. For example, if versioning were being used and the entity being PUT included changes to a resource which conflict with those made by an earlier (third-party) request, the server might use the 409 response to indicate that it can't complete the request. In this case, the response entity would likely contain a list of the differences between the two versions in a format defined by the response Content-Type.


In my case, I would like to PUT a string, that must be unique, to a database via an API. Before adding it to the database, I am checking that it is not already in the database.

If it is, I will return "Error: The string is already in the database", 409.

I believe this is what the OP wanted: an error code suitable for when the data does not pass the server's criteria.

Difference between "read commited" and "repeatable read"

Read committed is an isolation level that guarantees that any data read was committed at the moment is read. It simply restricts the reader from seeing any intermediate, uncommitted, 'dirty' read. It makes no promise whatsoever that if the transaction re-issues the read, will find the Same data, data is free to change after it was read.

Repeatable read is a higher isolation level, that in addition to the guarantees of the read committed level, it also guarantees that any data read cannot change, if the transaction reads the same data again, it will find the previously read data in place, unchanged, and available to read.

The next isolation level, serializable, makes an even stronger guarantee: in addition to everything repeatable read guarantees, it also guarantees that no new data can be seen by a subsequent read.

Say you have a table T with a column C with one row in it, say it has the value '1'. And consider you have a simple task like the following:

BEGIN TRANSACTION;
SELECT * FROM T;
WAITFOR DELAY '00:01:00'
SELECT * FROM T;
COMMIT;

That is a simple task that issue two reads from table T, with a delay of 1 minute between them.

  • under READ COMMITTED, the second SELECT may return any data. A concurrent transaction may update the record, delete it, insert new records. The second select will always see the new data.
  • under REPEATABLE READ the second SELECT is guaranteed to display at least the rows that were returned from the first SELECT unchanged. New rows may be added by a concurrent transaction in that one minute, but the existing rows cannot be deleted nor changed.
  • under SERIALIZABLE reads the second select is guaranteed to see exactly the same rows as the first. No row can change, nor deleted, nor new rows could be inserted by a concurrent transaction.

If you follow the logic above you can quickly realize that SERIALIZABLE transactions, while they may make life easy for you, are always completely blocking every possible concurrent operation, since they require that nobody can modify, delete nor insert any row. The default transaction isolation level of the .Net System.Transactions scope is serializable, and this usually explains the abysmal performance that results.

And finally, there is also the SNAPSHOT isolation level. SNAPSHOT isolation level makes the same guarantees as serializable, but not by requiring that no concurrent transaction can modify the data. Instead, it forces every reader to see its own version of the world (it's own 'snapshot'). This makes it very easy to program against as well as very scalable as it does not block concurrent updates. However, that benefit comes with a price: extra server resource consumption.

Supplemental reads:

How to use WinForms progress bar?

There is Task exists, It is unnesscery using BackgroundWorker, Task is more simple. for example:

ProgressDialog.cs:

   public partial class ProgressDialog : Form
    {
        public System.Windows.Forms.ProgressBar Progressbar { get { return this.progressBar1; } }

        public ProgressDialog()
        {
            InitializeComponent();
        }

        public void RunAsync(Action action)
        {
            Task.Run(action);
        }
    }

Done! Then you can reuse ProgressDialog anywhere:

var progressDialog = new ProgressDialog();
progressDialog.Progressbar.Value = 0;
progressDialog.Progressbar.Maximum = 100;

progressDialog.RunAsync(() =>
{
    for (int i = 0; i < 100; i++)
    {
        Thread.Sleep(1000)
        this.progressDialog.Progressbar.BeginInvoke((MethodInvoker)(() => {
            this.progressDialog.Progressbar.Value += 1;
        }));
    }
});

progressDialog.ShowDialog();

Storyboard doesn't contain a view controller with identifier

Identity located in Identity Inspector tab named Storyboard ID for Xcode 6.3.2 and checked Use Storyboard ID option. enter image description here

Combining Two Images with OpenCV

in OpenCV 3.0 you can use it easily as follow:

#combine 2 images same as to concatenate images with two different sizes
h1, w1 = img1.shape[:2]
h2, w2 = img2.shape[:2]
#create empty martrix (Mat)
res = np.zeros(shape=(max(h1, h2), w1 + w2, 3), dtype=np.uint8)
# assign BGR values to concatenate images
for i in range(res.shape[2]):
    # assign img1 colors
    res[:h1, :w1, i] = np.ones([img1.shape[0], img1.shape[1]]) * img1[:, :, i]
    # assign img2 colors
    res[:h2, w1:w1 + w2, i] = np.ones([img2.shape[0], img2.shape[1]]) * img2[:, :, i]

output_img = res.astype('uint8')

Remove all child elements of a DOM node in JavaScript

simply only IE:

parentElement.removeNode(true);

true - means to do deep removal - which means that all child are also removed

Html helper for <input type="file" />

Or you could do it properly:

In your HtmlHelper Extension class:

public static MvcHtmlString FileFor<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression)
    {
        return helper.FileFor(expression, null);
    }

public static MvcHtmlString FileFor<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression, object htmlAttributes)
    {
        var builder = new TagBuilder("input");

        var id = helper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(ExpressionHelper.GetExpressionText(expression));
        builder.GenerateId(id);
        builder.MergeAttribute("name", id);
        builder.MergeAttribute("type", "file");

        builder.MergeAttributes(new RouteValueDictionary(htmlAttributes));

        // Render tag
        return MvcHtmlString.Create(builder.ToString(TagRenderMode.SelfClosing));
    }

This line:

var id = helper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(ExpressionHelper.GetExpressionText(expression));

Generates an id unique to the model, you know in lists and stuff. model[0].Name etc.

Create the correct property in the model:

public HttpPostedFileBase NewFile { get; set; }

Then you need to make sure your form will send files:

@using (Html.BeginForm("Action", "Controller", FormMethod.Post, new { enctype = "multipart/form-data" }))

Then here's your helper:

@Html.FileFor(x => x.NewFile)

Bootstrap 3 Glyphicons are not working

Note to readers: be sure to read @user2261073's comment and @Jeff's answer concerning a bug in the customizer. It's likely the cause of your problem.


The font file isn't being loaded correctly. Check if the files are in their expected location.

@font-face {
  font-family: 'Glyphicons Halflings';
  src: url('../fonts/glyphicons-halflings-regular.eot');
  src: url('../fonts/glyphicons-halflings-regular.eot?#iefix') format('embedded-opentype'), url('../fonts/glyphicons-halflings-regular.woff') format('woff'), url('../fonts/glyphicons-halflings-regular.ttf') format('truetype'), url('../fonts/glyphicons-halflings-regular.svg#glyphicons-halflingsregular') format('svg');
}

As indicated by Daniel, it might also be a mimetype issue. Chrome's dev tools show downloaded fonts in the network tab:

chrome network tab font download

How to find the length of an array in shell?

this works well for me

    arglen=$#
    argparam=$*
    if [ $arglen -eq '3' ];
    then
            echo Valid Number of arguments
            echo "Arguments are $*"
    else
            echo only four arguments are allowed
    fi

What's the best way to get the last element of an array without deleting it?

Use the end() function.

$array = [1,2,3,4,5];
$last = end($array); // 5