Hide/Show components in react native

Very Easy. Just change to () => this.showCancel() like below:

<TextInput
        onFocus={() => this.showCancel() }
        onChangeText={(text) => this.doSearch({input: text})} />

<TouchableHighlight 
    onPress={this.hideCancel()}>
    <View>
        <Text style={styles.cancelButtonText}>Cancel</Text>
    </View>
</TouchableHighlight>

How to enable loglevel debug on Apache2 server

Edit: note that this answer is 3+ years old. For newer versions of apache, please see the answer by sp00n. Leaving this answer for users of older versions of apache.

For older version apache:

For debugging mod_rewrite issues, you'll want to use RewriteLogLevel and RewriteLog:

RewriteLogLevel 3
RewriteLog "/usr/local/var/apache/logs/rewrite.log"

how do you insert null values into sql server

If you're using SSMS (or old school Enterprise Manager) to edit the table directly, press CTRL+0 to add a null.

How to get $HOME directory of different user in bash script?

I was also looking for this, but didn't want to impersonate a user to simply acquire a path!

user_path=$(grep $username /etc/passwd|cut -f6 -d":");

Now in your script, you can refer to $user_path in most cases would be /home/username

Assumes: You have previously set $username with the value of the intended users username. Source: http://www.unix.com/shell-programming-and-scripting/171782-cut-fields-etc-passwd-file-into-variables.html

Run JavaScript when an element loses focus

You're looking for the onblur event. Look here, for more details.

Printf long long int in C with GCC?

For portable code, the macros in inttypes.h may be used. They expand to the correct ones for the platform.

E.g. for 64 bit integer, the macro PRId64 can be used.

int64_t n = 7;
printf("n is %" PRId64 "\n", n);

Using column alias in WHERE clause of MySQL query produces an error

I am using mysql 5.5.24 and the following code works:

select * from (
SELECT `users`.`first_name`, `users`.`last_name`, `users`.`email`,
SUBSTRING(`locations`.`raw`,-6,4) AS `guaranteed_postcode`
FROM `users` LEFT OUTER JOIN `locations`
ON `users`.`id` = `locations`.`user_id`
) as a
WHERE guaranteed_postcode NOT IN --this is where the fake col is being used
(
 SELECT `postcode` FROM `postcodes` WHERE `region` IN
 (
  'australia'
 )
)

Twitter API returns error 215, Bad Authentication Data

Try this twitter API explorer, you can sign in as a developer and query whatever you want.

How to go to a URL using jQuery?

why not using?

location.href='http://www.example.com';

_x000D_

<!DOCTYPE html>_x000D_
<html>_x000D_
_x000D_
<head>_x000D_
  <script>_x000D_
    function goToURL() {_x000D_
      location.href = 'http://google.it';_x000D_
_x000D_
    }_x000D_
  </script>_x000D_
</head>_x000D_
_x000D_
<body>_x000D_
  <a href="javascript:void(0)" onclick="goToURL(); return false;">Go To URL</a>_x000D_
</body>_x000D_
_x000D_
</html>

_x000D_

Number of days in particular month of particular year?

This worked fine for me.

This is a Sample Output

import java.util.*;

public class DaysInMonth { 

    public static void main(String args []) { 

        Scanner input = new Scanner(System.in); 
        System.out.print("Enter a year:"); 

        int year = input.nextInt(); //Moved here to get input after the question is asked 

        System.out.print("Enter a month:"); 
        int month = input.nextInt(); //Moved here to get input after the question is asked 

        int days = 0; //changed so that it just initializes the variable to zero
        boolean isLeapYear = (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0); 

        switch (month) { 
            case 1: 
                days = 31; 
                break; 
            case 2: 
                if (isLeapYear) 
                    days = 29; 
                else 
                    days = 28; 
                break; 
            case 3: 
                days = 31; 
                break; 
            case 4: 
                days = 30; 
                break; 
            case 5: 
                days = 31; 
                break; 
            case 6: 
                days = 30; 
                break; 
            case 7: 
                days = 31; 
                break; 
            case 8: 
                days = 31; 
                break; 
            case 9: 
                days = 30; 
                break; 
            case 10: 
                days = 31; 
                break; 
            case 11: 
                days = 30; 
                break; 
            case 12: 
                days = 31; 
                break; 
            default: 
                String response = "Have a Look at what you've done and try again";
                System.out.println(response); 
                System.exit(0); 
        } 

        String response = "There are " + days + " Days in Month " + month + " of Year " + year + ".\n"; 
        System.out.println(response); // new line to show the result to the screen. 
    } 
} //[email protected]

Aren't promises just callbacks?

No promises are just wrapper on callbacks

example You can use javascript native promises with node js

my cloud 9 code link : https://ide.c9.io/adx2803/native-promises-in-node

/**
* Created by dixit-lab on 20/6/16.
*/

var express = require('express');
var request = require('request');   //Simplified HTTP request client.


var app = express();

function promisify(url) {
    return new Promise(function (resolve, reject) {
    request.get(url, function (error, response, body) {
    if (!error && response.statusCode == 200) {
        resolve(body);
    }
    else {
        reject(error);
    }
    })
    });
}

//get all the albums of a user who have posted post 100
app.get('/listAlbums', function (req, res) {
//get the post with post id 100
promisify('http://jsonplaceholder.typicode.com/posts/100').then(function (result) {
var obj = JSON.parse(result);
return promisify('http://jsonplaceholder.typicode.com/users/' + obj.userId + '/albums')
})
.catch(function (e) {
    console.log(e);
})
.then(function (result) {
    res.end(result);
}
)

})


var server = app.listen(8081, function () {

var host = server.address().address
var port = server.address().port

console.log("Example app listening at http://%s:%s", host, port)

})


//run webservice on browser : http://localhost:8081/listAlbums

How do you implement a circular buffer in C?

First, the headline. You don't need modulo arithmetic to wrap the buffer if you use bit ints to hold the head & tail "pointers", and size them so they are perfectly in synch. IE: 4096 stuffed into a 12-bit unsigned int is 0 all by itself, unmolested in any way. Eliminating modulo arithmetic, even for powers of 2, doubles the speed - almost exactly.

10 million iterations of filling and draining a 4096 buffer of any type of data elements takes 52 seconds on my 3rd Gen i7 Dell XPS 8500 using Visual Studio 2010's C++ compiler with default inlining, and 1/8192nd of that to service a datum.

I'd RX rewriting the test loops in main() so they no longer control the flow - which is, and should be, controlled by the return values indicating the buffer is full or empty, and the attendant break; statements. IE: the filler and drainer should be able to bang against each other without corruption or instability. At some point I hope to multi-thread this code, whereupon that behavior will be crucial.

The QUEUE_DESC (queue descriptor) and initialization function forces all buffers in this code to be a power of 2. The above scheme will NOT work otherwise. While on the subject, note that QUEUE_DESC is not hard-coded, it uses a manifest constant (#define BITS_ELE_KNT) for its construction. (I'm assuming a power of 2 is sufficient flexibility here)

To make the buffer size run-time selectable, I tried different approaches (not shown here), and settled on using USHRTs for Head, Tail, EleKnt capable of managing a FIFO buffer[USHRT]. To avoid modulo arithmetic I created a mask to && with Head, Tail, but that mask turns out to be (EleKnt -1), so just use that. Using USHRTS instead of bit ints increased performance ~ 15% on a quiet machine. Intel CPU cores have always been faster than their buses, so on a busy, shared machine, packing your data structures gets you loaded and executing ahead of other, competing threads. Trade-offs.

Note the actual storage for the buffer is allocated on the heap with calloc(), and the pointer is at the base of the struct, so the struct and the pointer have EXACTLY the same address. IE; no offset required to be added to the struct address to tie up registers.

In that same vein, all of the variables attendant with servicing the buffer are physically adjacent to the buffer, bound into the same struct, so the compiler can make beautiful assembly language. You'll have to kill the inline optimization to see any assembly, because otherwise it gets crushed into oblivion.

To support the polymorphism of any data type, I've used memcpy() instead of assignments. If you only need the flexibility to support one random variable type per compile, then this code works perfectly.

For polymorphism, you just need to know the type and it's storage requirement. The DATA_DESC array of descriptors provides a way to keep track of each datum that gets put in QUEUE_DESC.pBuffer so it can be retrieved properly. I'd just allocate enough pBuffer memory to hold all of the elements of the largest data type, but keep track of how much of that storage a given datum is actually using in DATA_DESC.dBytes. The alternative is to reinvent a heap manager.

This means QUEUE_DESC's UCHAR *pBuffer would have a parallel companion array to keep track of data type, and size, while a datum's storage location in pBuffer would remain just as it is now. The new member would be something like DATA_DESC *pDataDesc, or, perhaps, DATA_DESC DataDesc[2^BITS_ELE_KNT] if you can find a way to beat your compiler into submission with such a forward reference. Calloc() is always more flexible in these situations.

You'd still memcpy() in Q_Put(),Q_Get, but the number of bytes actually copied would be determined by DATA_DESC.dBytes, not QUEUE_DESC.EleBytes. The elements are potentially all of different types/sizes for any given put or get.

I believe this code satisfies the speed and buffer size requirements, and can be made to satisfy the requirement for 6 different data types. I've left the many test fixtures in, in the form of printf() statements, so you can satisfy yourself (or not) that the code works properly. The random number generator demonstrates that the code works for any random head/tail combo.

enter code here
// Queue_Small.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <stdio.h>
#include <time.h>
#include <limits.h>
#include <stdlib.h>
#include <malloc.h>
#include <memory.h>
#include <math.h>

#define UCHAR unsigned char
#define ULONG unsigned long
#define USHRT unsigned short
#define dbl   double
/* Queue structure */
#define QUEUE_FULL_FLAG 1
#define QUEUE_EMPTY_FLAG -1
#define QUEUE_OK 0
//  
#define BITS_ELE_KNT    12  //12 bits will create 4.096 elements numbered 0-4095
//
//typedef struct    {
//  USHRT dBytes:8;     //amount of QUEUE_DESC.EleBytes storage used by datatype
//  USHRT dType :3; //supports 8 possible data types (0-7)
//  USHRT dFoo  :5; //unused bits of the unsigned short host's storage
// }    DATA_DESC;
//  This descriptor gives a home to all the housekeeping variables
typedef struct  {
    UCHAR   *pBuffer;   //  pointer to storage, 16 to 4096 elements
    ULONG Tail  :BITS_ELE_KNT;  //  # elements, with range of 0-4095
    ULONG Head  :BITS_ELE_KNT;  //  # elements, with range of 0-4095
    ULONG EleBytes  :8;     //  sizeof(elements) with range of 0-256 bytes
    // some unused bits will be left over if BITS_ELE_KNT < 12
    USHRT EleKnt    :BITS_ELE_KNT +1;// 1 extra bit for # elements (1-4096)
    //USHRT Flags   :(8*sizeof(USHRT) - BITS_ELE_KNT +1);   //  flags you can use
    USHRT   IsFull  :1;     // queue is full
    USHRT   IsEmpty :1;     // queue is empty
    USHRT   Unused  :1;     // 16th bit of USHRT
}   QUEUE_DESC;

//  ---------------------------------------------------------------------------
//  Function prototypes
QUEUE_DESC *Q_Init(QUEUE_DESC *Q, int BitsForEleKnt, int DataTypeSz);
int Q_Put(QUEUE_DESC *Q, UCHAR *pNew);
int Q_Get(UCHAR *pOld, QUEUE_DESC *Q);
//  ---------------------------------------------------------------------------
QUEUE_DESC *Q_Init(QUEUE_DESC *Q, int BitsForEleKnt, int DataTypeSz)    {
    memset((void *)Q, 0, sizeof(QUEUE_DESC));//init flags and bit integers to zero
    //select buffer size from powers of 2 to receive modulo 
    //                arithmetic benefit of bit uints overflowing
    Q->EleKnt   =   (USHRT)pow(2.0, BitsForEleKnt);
    Q->EleBytes =   DataTypeSz; // how much storage for each element?
    //  Randomly generated head, tail a test fixture only. 
    //      Demonstrates that the queue can be entered at a random point 
    //      and still perform properly. Normally zero
    srand(unsigned(time(NULL)));    // seed random number generator with current time
    Q->Head = Q->Tail = rand(); // supposed to be set to zero here, or by memset
    Q->Head = Q->Tail = 0;
    //  allocate queue's storage
    if(NULL == (Q->pBuffer = (UCHAR *)calloc(Q->EleKnt, Q->EleBytes)))  {
        return NULL;
    }   else    {
        return Q;
    }
}
//  ---------------------------------------------------------------------------
int Q_Put(QUEUE_DESC *Q, UCHAR *pNew)   
{
    memcpy(Q->pBuffer + (Q->Tail * Q->EleBytes), pNew, Q->EleBytes);
    if(Q->Tail == (Q->Head + Q->EleKnt)) {
        //  Q->IsFull = 1;
        Q->Tail += 1;   
        return QUEUE_FULL_FLAG; //  queue is full
    }
    Q->Tail += 1;   //  the unsigned bit int MUST wrap around, just like modulo
    return QUEUE_OK; // No errors
}
//  ---------------------------------------------------------------------------
int Q_Get(UCHAR *pOld, QUEUE_DESC *Q)   
{
    memcpy(pOld, Q->pBuffer + (Q->Head * Q->EleBytes), Q->EleBytes);
    Q->Head += 1;   //  the bit int MUST wrap around, just like modulo

    if(Q->Head == Q->Tail)      {
        //  Q->IsEmpty = 1;
        return QUEUE_EMPTY_FLAG; // queue Empty - nothing to get
    }
    return QUEUE_OK; // No errors
}
//
//  ---------------------------------------------------------------------------
int _tmain(int argc, _TCHAR* argv[])    {
//  constrain buffer size to some power of 2 to force faux modulo arithmetic
    int LoopKnt = 1000000;  //  for benchmarking purposes only
    int k, i=0, Qview=0;
    time_t start;
    QUEUE_DESC Queue, *Q;
    if(NULL == (Q = Q_Init(&Queue, BITS_ELE_KNT, sizeof(int)))) {
        printf("\nProgram failed to initialize. Aborting.\n\n");
        return 0;
    }

    start = clock();
    for(k=0; k<LoopKnt; k++)    {
        //printf("\n\n Fill'er up please...\n");
        //Q->Head = Q->Tail = rand();
        for(i=1; i<= Q->EleKnt; i++)    {
            Qview = i*i;
            if(QUEUE_FULL_FLAG == Q_Put(Q, (UCHAR *)&Qview))    {
                //printf("\nQueue is full at %i \n", i);
                //printf("\nQueue value of %i should be %i squared", Qview, i);
                break;
            }
            //printf("\nQueue value of %i should be %i squared", Qview, i);
        }
        //  Get data from queue until completely drained (empty)
        //
        //printf("\n\n Step into the lab, and see what's on the slab... \n");
        Qview = 0;
        for(i=1; i; i++)    {
            if(QUEUE_EMPTY_FLAG == Q_Get((UCHAR *)&Qview, Q))   {
                //printf("\nQueue value of %i should be %i squared", Qview, i);
                //printf("\nQueue is empty at %i", i);
                break;
            }
            //printf("\nQueue value of %i should be %i squared", Qview, i);
        }
        //printf("\nQueue head value is %i, tail is %i\n", Q->Head, Q->Tail);
    }
    printf("\nQueue time was %5.3f to fill & drain %i element queue  %i times \n", 
                     (dbl)(clock()-start)/(dbl)CLOCKS_PER_SEC,Q->EleKnt, LoopKnt);
    printf("\nQueue head value is %i, tail is %i\n", Q->Head, Q->Tail);
    getchar();
    return 0;
}

Django: save() vs update() to update the database?

Using update directly is more efficient and could also prevent integrity problems.

From the official documentation https://docs.djangoproject.com/en/3.0/ref/models/querysets/#django.db.models.query.QuerySet.update

If you’re just updating a record and don’t need to do anything with the model object, the most efficient approach is to call update(), rather than loading the model object into memory. For example, instead of doing this:
e = Entry.objects.get(id=10)
e.comments_on = False
e.save()
…do this:
Entry.objects.filter(id=10).update(comments_on=False)
Using update() also prevents a race condition wherein something might change in your database in the short period of time between loading the object and calling save().

Effect of NOLOCK hint in SELECT statements

The answer is Yes if the query is run multiple times at once, because each transaction won't need to wait for the others to complete. However, If the query is run once on its own then the answer is No.
Yes. There's a significant probability that careful use of WITH(NOLOCK) will speed up your database overall. It means that other transactions won't have to wait for this SELECT statement to finish, but on the other hand, other transactions will slow down as they're now sharing their processing time with a new transaction.

Be careful to only use WITH (NOLOCK) in SELECT statements on tables that have a clustered index.

WITH(NOLOCK) is often exploited as a magic way to speed up database read transactions.

The result set can contain rows that have not yet been committed, that are often later rolled back.

If WITH(NOLOCK) is applied to a table that has a non-clustered index then row-indexes can be changed by other transactions as the row data is being streamed into the result-table. This means that the result-set can be missing rows or display the same row multiple times.

READ COMMITTED adds an additional issue where data is corrupted within a single column where multiple users change the same cell simultaneously.

Setting width and height

I cannot believe nobody talked about using a relative parent element.

Code:

<div class="chart-container" style="position: relative; height:40vh; width:80vw">
  <canvas id="chart"></canvas>
</div>

Sources: Official documentation

Compare two dates in Java

Here's what you can do for say yyyy-mm-dd comparison:

GregorianCalendar gc= new GregorianCalendar();
gc.setTimeInMillis(System.currentTimeMillis());
gc.roll(GregorianCalendar.DAY_OF_MONTH, true);

Date d1 = new Date();
Date d2 = gc.getTime();

SimpleDateFormat sf= new SimpleDateFormat("yyyy-MM-dd");

if(sf.format(d2).hashCode() < sf.format(d1).hashCode())
{
    System.out.println("date 2 is less than date 1");
}
else
{
    System.out.println("date 2 is equal or greater than date 1");
}

Is there a way to delete all the data from a topic or delete the topic before every run?

We tried pretty much what the other answers are describing with moderate level of success. What really worked for us (Apache Kafka 0.8.1) is the class command

sh kafka-run-class.sh kafka.admin.DeleteTopicCommand --topic yourtopic --zookeeper localhost:2181

Select tableview row programmatically

Like Jaanus told:

Calling this (-selectRowAtIndexPath:animated:scrollPosition:) method does not cause the delegate to receive a tableView:willSelectRowAtIndexPath: or tableView:didSelectRowAtIndexPath: message, nor will it send UITableViewSelectionDidChangeNotification notifications to observers.

So you just have to call the delegate method yourself.

For example:

Swift 3 version:

let indexPath = IndexPath(row: 0, section: 0);
self.tableView.selectRow(at: indexPath, animated: false, scrollPosition: UITableViewScrollPosition.none)
self.tableView(self.tableView, didSelectRowAt: indexPath)

ObjectiveC version:

NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.tableView selectRowAtIndexPath:indexPath 
                            animated:YES 
                      scrollPosition:UITableViewScrollPositionNone];
[self tableView:self.tableView didSelectRowAtIndexPath:indexPath];

Swift 2.3 version:

 let indexPath = NSIndexPath(forRow: 0, inSection: 0);
 self.tableView.selectRowAtIndexPath(indexPath, animated: false, scrollPosition: UITableViewScrollPosition.None)
 self.tableView(self.tableView, didSelectRowAtIndexPath: indexPath)

Send Post Request with params using Retrofit

build.gradle

      compile 'com.google.code.gson:gson:2.6.2'

      compile 'com.squareup.retrofit2:retrofit:2.1.0'// compulsory

      compile 'com.squareup.retrofit2:converter-gson:2.1.0' //for retrofit conversion

Login APi Put Two Parameters

    {
        "UserId": "1234",
        "Password":"1234"
    }

Login Response

    {
        "UserId": "1234",
        "FirstName": "Keshav",
        "LastName": "Gera",
        "ProfilePicture": "312.113.221.1/GEOMVCAPI/Files/1.500534651736E12p.jpg"
    }

APIClient.java

    import retrofit2.Retrofit;
    import retrofit2.converter.gson.GsonConverterFactory;

    class APIClient {

        public static final String BASE_URL = "Your Base Url ";
        private static Retrofit retrofit = null;

        public static Retrofit getClient() {
            if (retrofit == null) {
                retrofit = new Retrofit.Builder()
                        .baseUrl(BASE_URL)
                        .addConverterFactory(GsonConverterFactory.create())
                        .build();
            }
            return retrofit;
        }
    }

APIInterface interface

    interface APIInterface {

        @POST("LoginController/Login")
        Call<LoginResponse> createUser(@Body LoginResponse login);
    }

Login Pojo

    package pojos;

    import com.google.gson.annotations.SerializedName;

    public class LoginResponse {


        @SerializedName("UserId")
        public String UserId;
        @SerializedName("FirstName")
        public String FirstName;
        @SerializedName("LastName")
        public String LastName;
        @SerializedName("ProfilePicture")
        public String ProfilePicture;
        @SerializedName("Password")
        public String Password;
        @SerializedName("ResponseCode")
        public String ResponseCode;
        @SerializedName("ResponseMessage")
        public String ResponseMessage;

        public LoginResponse(String UserId, String Password) {
            this.UserId = UserId;
            this.Password = Password;
        }

        public String getUserId() {
            return UserId;
        }

        public String getFirstName() {
            return FirstName;
        }

        public String getLastName() {
            return LastName;
        }

        public String getProfilePicture() {
            return ProfilePicture;
        }

        public String getResponseCode() {
            return ResponseCode;
        }

        public String getResponseMessage() {
            return ResponseMessage;
        }
    }

MainActivity

    package com.keshav.retrofitloginexampleworkingkeshav;

    import android.app.Dialog;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.util.Log;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;
    import android.widget.Toast;

    import pojos.LoginResponse;
    import retrofit2.Call;
    import retrofit2.Callback;
    import retrofit2.Response;
    import utilites.CommonMethod;

    public class MainActivity extends AppCompatActivity {

        TextView responseText;
        APIInterface apiInterface;

        Button loginSub;
        EditText et_Email;
        EditText et_Pass;
        private Dialog mDialog;
        String userId;
        String password;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            apiInterface = APIClient.getClient().create(APIInterface.class);

            loginSub = (Button) findViewById(R.id.loginSub);
            et_Email = (EditText) findViewById(R.id.edtEmail);
            et_Pass = (EditText) findViewById(R.id.edtPass);

            loginSub.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (checkValidation()) {
                        if (CommonMethod.isNetworkAvailable(MainActivity.this))
                            loginRetrofit2Api(userId, password);
                        else
                            CommonMethod.showAlert("Internet Connectivity Failure", MainActivity.this);
                    }
                }
            });
        }

        private void loginRetrofit2Api(String userId, String password) {
            final LoginResponse login = new LoginResponse(userId, password);
            Call<LoginResponse> call1 = apiInterface.createUser(login);
            call1.enqueue(new Callback<LoginResponse>() {
                @Override
                public void onResponse(Call<LoginResponse> call, Response<LoginResponse> response) {
                    LoginResponse loginResponse = response.body();

                    Log.e("keshav", "loginResponse 1 --> " + loginResponse);
                    if (loginResponse != null) {
                        Log.e("keshav", "getUserId          -->  " + loginResponse.getUserId());
                        Log.e("keshav", "getFirstName       -->  " + loginResponse.getFirstName());
                        Log.e("keshav", "getLastName        -->  " + loginResponse.getLastName());
                        Log.e("keshav", "getProfilePicture  -->  " + loginResponse.getProfilePicture());

                        String responseCode = loginResponse.getResponseCode();
                        Log.e("keshav", "getResponseCode  -->  " + loginResponse.getResponseCode());
                        Log.e("keshav", "getResponseMessage  -->  " + loginResponse.getResponseMessage());
                        if (responseCode != null && responseCode.equals("404")) {
                            Toast.makeText(MainActivity.this, "Invalid Login Details \n Please try again", Toast.LENGTH_SHORT).show();
                        } else {
                            Toast.makeText(MainActivity.this, "Welcome " + loginResponse.getFirstName(), Toast.LENGTH_SHORT).show();
                        }
                    }
                }

                @Override
                public void onFailure(Call<LoginResponse> call, Throwable t) {
                    Toast.makeText(getApplicationContext(), "onFailure called ", Toast.LENGTH_SHORT).show();
                    call.cancel();
                }
            });
        }

        public boolean checkValidation() {
            userId = et_Email.getText().toString();
            password = et_Pass.getText().toString();

            Log.e("Keshav", "userId is -> " + userId);
            Log.e("Keshav", "password is -> " + password);

            if (et_Email.getText().toString().trim().equals("")) {
                CommonMethod.showAlert("UserId Cannot be left blank", MainActivity.this);
                return false;
            } else if (et_Pass.getText().toString().trim().equals("")) {
                CommonMethod.showAlert("password Cannot be left blank", MainActivity.this);
                return false;
            }
            return true;
        }
    }

CommonMethod.java

    public class CommonMethod {


        public static final String DISPLAY_MESSAGE_ACTION =
                "com.codecube.broking.gcm";

        public static final String EXTRA_MESSAGE = "message";

        public  static boolean isNetworkAvailable(Context ctx) {
            ConnectivityManager connectivityManager
                    = (ConnectivityManager)ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
            return activeNetworkInfo != null && activeNetworkInfo.isConnected();
        }

        public static void showAlert(String message, Activity context) {

            final AlertDialog.Builder builder = new AlertDialog.Builder(context);
            builder.setMessage(message).setCancelable(false)
                    .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {

                        }
                    });
            try {
                builder.show();
            } catch (Exception e) {
                e.printStackTrace();
            }

        }
    }

activity_main.xml

    <LinearLayout android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:focusable="true"
        android:focusableInTouchMode="true"
        android:orientation="vertical"
        xmlns:android="http://schemas.android.com/apk/res/android">

            <ImageView
                android:id="@+id/imgLogin"
                android:layout_width="200dp"
                android:layout_height="150dp"
                android:layout_gravity="center"
                android:layout_marginTop="20dp"
                android:padding="5dp"
                android:background="@mipmap/ic_launcher_round"
                />

            <TextView
                android:id="@+id/txtLogo"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/imgLogin"
                android:layout_centerHorizontal="true"
                android:text="Holostik Track and Trace"
                android:textSize="20dp"
                android:visibility="gone" />

            <android.support.design.widget.TextInputLayout
                android:id="@+id/textInputLayout1"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="@dimen/box_layout_margin_left"
                android:layout_marginRight="@dimen/box_layout_margin_right"
                android:layout_marginTop="8dp"
                android:padding="@dimen/text_input_padding">

                <EditText
                    android:id="@+id/edtEmail"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="5dp"
                    android:ems="10"
                    android:fontFamily="sans-serif"
                    android:gravity="top"
                    android:hint="Login ID"
                    android:maxLines="10"
                    android:paddingLeft="@dimen/edit_input_padding"
                    android:paddingRight="@dimen/edit_input_padding"
                    android:paddingTop="@dimen/edit_input_padding"
                    android:singleLine="true"></EditText>

            </android.support.design.widget.TextInputLayout>

            <android.support.design.widget.TextInputLayout
                android:id="@+id/textInputLayout2"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/textInputLayout1"
                android:layout_marginLeft="@dimen/box_layout_margin_left"
                android:layout_marginRight="@dimen/box_layout_margin_right"
                android:padding="@dimen/text_input_padding">

                <EditText
                    android:id="@+id/edtPass"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:focusable="true"
                    android:fontFamily="sans-serif"
                    android:hint="Password"
                    android:inputType="textPassword"

                    android:singleLine="true" />

            </android.support.design.widget.TextInputLayout>

            <RelativeLayout
                android:id="@+id/rel12"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/textInputLayout2"
                android:layout_marginTop="10dp"
                android:layout_marginLeft="10dp"
                >

                <Button
                    android:id="@+id/loginSub"
                    android:layout_width="wrap_content"
                    android:layout_height="45dp"
                    android:layout_alignParentRight="true"
                    android:layout_centerVertical="true"
                    android:background="@drawable/border_button"
                    android:paddingLeft="30dp"
                    android:paddingRight="30dp"
                    android:layout_marginRight="10dp"
                    android:text="Login"
                    android:textColor="#ffffff" />    
            </RelativeLayout>

    </LinearLayout>

Code to loop through all records in MS Access

Found a good code with comments explaining each statement. Code found at - accessallinone

Sub DAOLooping()
On Error GoTo ErrorHandler

Dim strSQL As String
Dim rs As DAO.Recordset

strSQL = "tblTeachers"
'For the purposes of this post, we are simply going to make 
'strSQL equal to tblTeachers.
'You could use a full SELECT statement such as:
'SELECT * FROM tblTeachers (this would produce the same result in fact).
'You could also add a Where clause to filter which records are returned:
'SELECT * FROM tblTeachers Where ZIPPostal = '98052'
' (this would return 5 records)

Set rs = CurrentDb.OpenRecordset(strSQL)
'This line of code instantiates the recordset object!!! 
'In English, this means that we have opened up a recordset 
'and can access its values using the rs variable.

With rs


    If Not .BOF And Not .EOF Then
    'We don’t know if the recordset has any records, 
    'so we use this line of code to check. If there are no records 
    'we won’t execute any code in the if..end if statement.    

        .MoveLast
        .MoveFirst
        'It is not necessary to move to the last record and then back 
        'to the first one but it is good practice to do so.

        While (Not .EOF)
        'With this code, we are using a while loop to loop 
        'through the records. If we reach the end of the recordset, .EOF 
        'will return true and we will exit the while loop.

            Debug.Print rs.Fields("teacherID") & " " & rs.Fields("FirstName")
            'prints info from fields to the immediate window

            .MoveNext
            'We need to ensure that we use .MoveNext, 
            'otherwise we will be stuck in a loop forever… 
            '(or at least until you press CTRL+Break)
        Wend

    End If

    .close
    'Make sure you close the recordset...
End With

ExitSub:
    Set rs = Nothing
    '..and set it to nothing
    Exit Sub
ErrorHandler:
    Resume ExitSub
End Sub

Recordsets have two important properties when looping through data, EOF (End-Of-File) and BOF (Beginning-Of-File). Recordsets are like tables and when you loop through one, you are literally moving from record to record in sequence. As you move through the records the EOF property is set to false but after you try and go past the last record, the EOF property becomes true. This works the same in reverse for the BOF property.

These properties let us know when we have reached the limits of a recordset.

C Program to find day of week given date

For Day of Week, years 2000 - 2099.

uint8_t rtc_DayOfWeek(uint8_t year, uint8_t month, uint8_t day)
{
    //static const uint8_t month_offset_table[] = {0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5}; // Typical table.

    // Added 1 to Jan, Feb. Subtracted 1 from each instead of adding 6 in calc below.

    static const uint8_t month_offset_table[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};

    // Year is 0 - 99, representing years 2000 - 2099

    // Month starts at 0.

    // Day starts at 1.

    // Subtract 1 in calc for Jan, Feb, only in leap years.
    // Subtracting 1 from year has the effect of subtracting 2 in leap years, subtracting 1 otherwise.
    // Adding 1 for Jan, Feb in Month Table so calc ends up subtracting 1 for Jan, Feb, only in leap years.
    // All of this complication to avoid the check if it is a leap year.
    if (month < 2) {
        year--;
    }

    // Century constant is 6. Subtract 1 from Month Table, so difference is 7.

    // Sunday (0), Monday (1) ...

    return (day + month_offset_table[month] + year + (year >> 2)) % 7;

} /* end rtc_DayOfWeek() */

Single Line Nested For Loops

You might be interested in itertools.product, which returns an iterable yielding tuples of values from all the iterables you pass it. That is, itertools.product(A, B) yields all values of the form (a, b), where the a values come from A and the b values come from B. For example:

import itertools

A = [50, 60, 70]
B = [0.1, 0.2, 0.3, 0.4]

print [a + b for a, b in itertools.product(A, B)]

This prints:

[50.1, 50.2, 50.3, 50.4, 60.1, 60.2, 60.3, 60.4, 70.1, 70.2, 70.3, 70.4]

Notice how the final argument passed to itertools.product is the "inner" one. Generally, itertools.product(a₀, a₁, ... a_n) is equal to [(i₀, i₁, ... i_n) for i_n in a_n for i_n-1 in a_n-1 ... for i₀ in a₀]

Change collations of all columns of all tables in SQL Server

Following script will work with table schema along with latest Types like (MAX), IMAGE, and etc. change your collation type according to your need on this line (SET @collate = 'DATABASE_DEFAULT';)

SQL SCRIPT HERE:

BEGIN
DECLARE @collate nvarchar(100);
declare @schema nvarchar(255);
DECLARE @table nvarchar(255);
DECLARE @column_name nvarchar(255);
DECLARE @column_id int;
DECLARE @data_type nvarchar(255);
DECLARE @max_length varchar(100);
DECLARE @row_id int;
DECLARE @sql nvarchar(max);
DECLARE @sql_column nvarchar(max);

SET @collate = 'DATABASE_DEFAULT';

DECLARE tbl_cursor CURSOR FOR SELECT (s.[name])schemaName, (o.[name])[tableName]
FROM sysobjects sy 
INNER JOIN sys.objects  o on o.name = sy.name
INNER JOIN sys.schemas s ON o.schema_id = s.schema_id
WHERE OBJECTPROPERTY(sy.id, N'IsUserTable') = 1

OPEN tbl_cursor FETCH NEXT FROM tbl_cursor INTO @schema,@table

WHILE @@FETCH_STATUS = 0
BEGIN
    DECLARE tbl_cursor_changed CURSOR FOR
        SELECT ROW_NUMBER() OVER (ORDER BY c.column_id) AS row_id
            , c.name column_name
            , t.Name data_type
            , c.max_length
            , c.column_id
        FROM sys.columns c
        JOIN sys.types t ON c.system_type_id = t.system_type_id
        LEFT OUTER JOIN sys.index_columns ic ON ic.object_id = c.object_id AND ic.column_id = c.column_id
        LEFT OUTER JOIN sys.indexes i ON ic.object_id = i.object_id AND ic.index_id = i.index_id
    WHERE c.object_id like OBJECT_ID(@schema+'.'+@table)
    ORDER BY c.column_id


    OPEN tbl_cursor_changed 
     FETCH NEXT FROM tbl_cursor_changed
    INTO @row_id, @column_name, @data_type, @max_length, @column_id



    WHILE @@FETCH_STATUS = 0
    BEGIN
    IF (@max_length = -1) SET @max_length = 'MAX';
        IF (@data_type LIKE '%char%')
        BEGIN TRY
            SET @sql = 'ALTER TABLE ' +@schema+'.'+ @table + ' ALTER COLUMN ' + @column_name + ' ' + @data_type + '(' + CAST(@max_length AS nvarchar(100)) + ') COLLATE ' + @collate
            print @sql
            EXEC sp_executesql @sql
        END TRY
        BEGIN CATCH
          PRINT 'ERROR:'
          PRINT @sql
        END CATCH

        FETCH NEXT FROM tbl_cursor_changed
        INTO @row_id, @column_name, @data_type, @max_length, @column_id

    END

    CLOSE tbl_cursor_changed
    DEALLOCATE tbl_cursor_changed

    FETCH NEXT FROM tbl_cursor
    INTO @schema, @table

END

CLOSE tbl_cursor
DEALLOCATE tbl_cursor

PRINT 'Collation For All Tables Done!'
END

Service vs IntentService in the Android platform

An IntentService is an extension of a Service that is made to ease the execution of a task that needs to be executed in background and in a seperated thread.

IntentService starts, create a thread and runs its task in the thread. once done, it cleans everything. Only one instance of a IntentService can run at the same time, several calls are enqueued.

It is very simple to use and very convenient for a lot of uses, for instance downloading stuff. But it has limitations that can make you want to use instead the more basic (not simple) Service.

For example, a service connected to a xmpp server and bound by activities cannot be simply done using an IntentService. You'll end up ignoring or overriding IntentService stuffs.

Usage of $broadcast(), $emit() And $on() in AngularJS

This little example shows how the $rootScope emit a event that will be listen by a children scope in another controller.

(function(){


angular
  .module('ExampleApp',[]);

angular
  .module('ExampleApp')
  .controller('ExampleController1', Controller1);

Controller1.$inject = ['$rootScope'];

function Controller1($rootScope) {
  var vm = this, 
      message = 'Hi my children scope boy';

  vm.sayHi = sayHi;

  function sayHi(){
    $rootScope.$broadcast('greeting', message);
  }

}

angular
  .module('ExampleApp')
  .controller('ExampleController2', Controller2);

Controller2.$inject = ['$scope'];

function Controller2($scope) {
  var vm = this;

  $scope.$on('greeting', listenGreeting)

  function listenGreeting($event, message){
    alert(['Message received',message].join(' : '));
  }

}


})();

http://codepen.io/gpincheiraa/pen/xOZwqa

The answer of @gayathri bottom explain technically the differences of all those methods in the scope angular concept and their implementations $scope and $rootScope.

Replace all whitespace characters

Actually it has been worked but

just try this.

take the value /\s/g into a string variable like

String a = /\s/g;

str = str.replaceAll(a,"X");

how concatenate two variables in batch script?

The way is correct, but can be improved a bit with the extended set-syntax.

set "var=xyz"

Sets the var to the content until the last quotation mark, this ensures that no "hidden" spaces are appended.

Your code would look like

set "var1=A"
set "var2=B"
set "AB=hi"
set "newvar=%var1%%var2%"
echo %newvar% is the concat of var1 and var2
echo !%newvar%! is the indirect content of newvar

Bootstrap 3 : Vertically Center Navigation Links when Logo Increasing The Height of Navbar

Bootstrap sets the height of the navbar automatically to 50px. The padding above and below links is set to 15px. I think that bootstrap is adding padding to your logo.

You can either remove some of the padding above and below your logo or you can add more padding above and below links.

Adding more padding should look something like this:

nav.navbar-inverse>li>a {
 padding-top: 25px;
 padding-bottom: 25px;
}

How to compare a local git branch with its remote branch?

To update remote-tracking branches, you need to type git fetch first and then :

git diff <mainbranch_path> <remotebranch_path>

You can git branch -a to list all branches (local and remote) then choose branch name from list (just remove remotes/ from remote branch name.

Example: git diff main origin/main (where "main" is local main branch and "origin/main" is a remote namely origin and main branch.)

Ansible: Store command's stdout in new variable?

If you want to go further and extract the exact information you want from the Playbook results, use JSON query language like jmespath, an example:

  - name: Sample Playbook
    // Fill up your task
    no_log: True
    register: example_output

  - name: Json Query
    set_fact:
      query_result:
        example_output:"{{ example_output | json_query('results[*].name') }}"

With block equivalent in C#?

A big fan of With here!

This is literally my current C# code:

if (SKYLib.AccountsPayable.Client.ApiAuthorization.Authorization.AccessTokenExpiry == null || SKYLib.AccountsPayable.Client.ApiAuthorization.Authorization.AccessTokenExpiry < DateTime.Now)
{
    SKYLib.AccountsPayable.Client.ApiAuthorization.Authorization.Refresh();
    _api = new SKYLib.AccountsPayable.Api.DefaultApi(new SKYLib.AccountsPayable.Client.Configuration { DefaultHeader = SKYLib.AccountsPayable.Client.ApiAuthorization.Authorization.ApiHeader });
}

In VB it could be:

With SKYLib.AccountsPayable.Client.ApiAuthorization.Authorization
    If .AccessTokenExpiry Is Nothing OrElse .AccessTokenExpiry < Now Then .Refresh()
    _api = New SKYLib.AccountsPayable.Api.DefaultApi(New SKYLib.AccountsPayable.Client.Configuration With {DefaultHeader = .ApiHeaders}
End With

Much clearer I think. You could even tweak it to be more concise by tuning the With variable. And, style-wise, I still have a choice! Perhaps something the C# Program Manager has overlooked.

As an aside, it's not very common to see this, but I have used it on occasion:

Instead of

Using oClient As HttpClient = New HttpClient
    With oClient
        .BaseAddress = New Uri("http://mysite")
        .Timeout = New TimeSpan(123)
        .PostAsync( ... )
    End With
End Using

You can use

With New HttpClient
    .BaseAddress = New Uri("http://mysite")
    .Timeout = New TimeSpan(123)
    .PostAsync( ... )
End With

You risk a wrist-slapping - as do I for posting! - but it seems that you get all the benefits of a Using statement in terms of disposal, etc without the extra rigmarole.

NOTE: This can go wrong occasionally, so only use it for non-critical code. Or not at all. Remember: You have a choice ...

Is there a 'foreach' function in Python 3?

The correct answer is "python collections do not have a foreach". In native python we need to resort to the external for _element_ in _collection_ syntax which is not what the OP is after.

Python is in general quite weak for functionals programming. There are a few libraries to mitigate a bit. I helped author one of these infixpy https://pypi.org/project/infixpy/

from infixpy import Seq
(Seq([1,2,3]).foreach(lambda x: print(x)))
1
2
3

Also see: Left to right application of operations on a list in Python 3

Relative paths based on file location instead of current working directory

@Martin Konecny's answer provides the correct answer, but - as he mentions - it only works if the actual script is not invoked through a symlink residing in a different directory.

This answer covers that case: a solution that also works when the script is invoked through a symlink or even a chain of symlinks:

Linux / GNU readlink solution:

If your script needs to run on Linux only or you know that GNU readlink is in the $PATH, use readlink -f, which conveniently resolves a symlink to its ultimate target:

 scriptDir=$(dirname -- "$(readlink -f -- "$BASH_SOURCE")")

^{Note that GNU readlink has 3 related options for resolving a symlink to its ultimate target's full path: -f (--canonicalize), -e (--canonicalize-existing), and -m (--canonicalize-missing) - see man readlink.

Since the target by definition exists in this scenario, any of the 3 options can be used; I've chosen -f here, because it is the most well-known one.}

Multi-(Unix-like-)platform solution (including platforms with a POSIX-only set of utilities):

If your script must run on any platform that:

has a readlink utility, but lacks the -f option (in the GNU sense of resolving a symlink to its ultimate target) - e.g., macOS.
- macOS uses an older version of the BSD implementation of readlink; note that recent versions of FreeBSD/PC-BSD do support -f.
does not even have readlink, but has POSIX-compatible utilities - e.g., HP-UX (thanks, @Charles Duffy).

The following solution, inspired by https://stackoverflow.com/a/1116890/45375, defines helper shell function, rreadlink(), which resolves a given symlink to its ultimate target in a loop - this function is in effect a POSIX-compliant implementation of GNU readlink's -e option, which is similar to the -f option, except that the ultimate target must exist.

Note: The function is a bash function, and is POSIX-compliant only in the sense that only POSIX utilities with POSIX-compliant options are used. For a version of this function that is itself written in POSIX-compliant shell code (for /bin/sh), see here.

If readlink is available, it is used (without options) - true on most modern platforms.
Otherwise, the output from ls -l is parsed, which is the only POSIX-compliant way to determine a symlink's target.
Caveat: this will break if a filename or path contains the literal substring -> - which is unlikely, however.
(Note that platforms that lack readlink may still provide other, non-POSIX methods for resolving a symlink; e.g., @Charles Duffy mentions HP-UX's find utility supporting the %l format char. with its -printf primary; in the interest of brevity the function does NOT try to detect such cases.)
An installable utility (script) form of the function below (with additional functionality) can be found as rreadlink in the npm registry; on Linux and macOS, install it with [sudo] npm install -g rreadlink; on other platforms (assuming they have bash), follow the manual installation instructions.

If the argument is a symlink, the ultimate target's canonical path is returned; otherwise, the argument's own canonical path is returned.

#!/usr/bin/env bash

# Helper function.
rreadlink() ( # execute function in a *subshell* to localize the effect of `cd`, ...

  local target=$1 fname targetDir readlinkexe=$(command -v readlink) CDPATH= 

  # Since we'll be using `command` below for a predictable execution
  # environment, we make sure that it has its original meaning.
  { \unalias command; \unset -f command; } &>/dev/null

  while :; do # Resolve potential symlinks until the ultimate target is found.
      [[ -L $target || -e $target ]] || { command printf '%s\n' "$FUNCNAME: ERROR: '$target' does not exist." >&2; return 1; }
      command cd "$(command dirname -- "$target")" # Change to target dir; necessary for correct resolution of target path.
      fname=$(command basename -- "$target") # Extract filename.
      [[ $fname == '/' ]] && fname='' # !! curiously, `basename /` returns '/'
      if [[ -L $fname ]]; then
        # Extract [next] target path, which is defined
        # relative to the symlink's own directory.
        if [[ -n $readlinkexe ]]; then # Use `readlink`.
          target=$("$readlinkexe" -- "$fname")
        else # `readlink` utility not available.
          # Parse `ls -l` output, which, unfortunately, is the only POSIX-compliant 
          # way to determine a symlink's target. Hypothetically, this can break with
          # filenames containig literal ' -> ' and embedded newlines.
          target=$(command ls -l -- "$fname")
          target=${target#* -> }
        fi
        continue # Resolve [next] symlink target.
      fi
      break # Ultimate target reached.
  done
  targetDir=$(command pwd -P) # Get canonical dir. path
  # Output the ultimate target's canonical path.
  # Note that we manually resolve paths ending in /. and /.. to make sure we
  # have a normalized path.
  if [[ $fname == '.' ]]; then
    command printf '%s\n' "${targetDir%/}"
  elif  [[ $fname == '..' ]]; then
    # Caveat: something like /var/.. will resolve to /private (assuming
    # /var@ -> /private/var), i.e. the '..' is applied AFTER canonicalization.
    command printf '%s\n' "$(command dirname -- "${targetDir}")"
  else
    command printf '%s\n' "${targetDir%/}/$fname"
  fi
)

# Determine ultimate script dir. using the helper function.
# Note that the helper function returns a canonical path.
scriptDir=$(dirname -- "$(rreadlink "$BASH_SOURCE")")

Format timedelta to string

I would seriously consider the Occam's Razor approach here:

td = str(timedelta).split('.')[0]

This returns a string without the microseconds

If you want to regenerate the datetime.timedelta object, just do this:

h,m,s = re.split(':', td)
new_delta = datetime.timedelta(hours=int(h),minutes=int(m),seconds=int(s))

2 years in, I love this language!

Setting Android Theme background color

Okay turned out that I made a really silly mistake. The device I am using for testing is running Android 4.0.4, API level 15.

The styles.xml file that I was editing is in the default values folder. I edited the styles.xml in values-v14 folder and it works all fine now.

Compare two objects' properties to find differences?

The real problem: How to get the difference of two sets?

The fastest way I've found is to convert the sets to dictionaries first, then diff 'em. Here's a generic approach:

static IEnumerable<T> DictionaryDiff<K, T>(Dictionary<K, T> d1, Dictionary<K, T> d2)
{
    return from x in d1 where !d2.ContainsKey(x.Key) select x.Value;
}

Then you can do something like this:

static public IEnumerable<PropertyInfo> PropertyDiff(Type t1, Type t2)
{
    var d1 = t1.GetProperties().ToDictionary(x => x.Name);
    var d2 = t2.GetProperties().ToDictionary(x => x.Name);
    return DictionaryDiff(d1, d2);
}

How to remove an unpushed outgoing commit in Visual Studio?

Open the history tab in Team Explorer from the Branches tile (right-click your branch). Then in the history right-click the commit before the one you don't want to push, choose Reset. That will move the branch back to that commit and should get rid of the extra commit you made. In order to reset before a given commit you thus have to select its parent.

Depending on what you want to do with the changes choose hard, which will get rid of them locally. Or choose soft which will undo the commit but will leave your working directory with the changes in your discarded commit.

Replace a value if null or undefined in JavaScript

Logical nullish assignment, 2020+ solution

A new operator has been added, ??=. This is equivalent to value = value ?? defaultValue.

||= and &&= are similar, links below.

This checks if left side is undefined or null, short-circuiting if already defined. If not, the left side is assigned the right-side value.

Basic Examples

let a          // undefined
let b = null
let c = false

a ??= true  // true
b ??= true  // true
c ??= true  // false

// Equivalent to
a = a ?? true

Object/Array Examples

let x = ["foo"]
let y = { foo: "fizz" }

x[0] ??= "bar"  // "foo"
x[1] ??= "bar"  // "bar"

y.foo ??= "buzz"  // "fizz"
y.bar ??= "buzz"  // "buzz"

x  // Array [ "foo", "bar" ]
y  // Object { foo: "fizz", bar: "buzz" }

Functional Example

function config(options) {
    options.duration ??= 100
    options.speed ??= 25
    return options
}

config({ duration: 555 })   // { duration: 555, speed: 25 }
config({})                  // { duration: 100, speed: 25 }
config({ duration: null })  // { duration: 100, speed: 25 }

??= Browser Support Nov 2020 - 77%

??= Mozilla Documentation

||= Mozilla Documentation

&&= Mozilla Documentation

Filter an array using a formula (without VBA)

Sounds like you're just trying to do a classic two-column lookup. http://www.dailydoseofexcel.com/archives/2009/04/21/vlookup-on-two-columns/

Tons of solutions for this, most simple is probably the following (which doesn't require an array formula):

=SUMPRODUCT((Lookup!A:A=Param!A1)*(Lookup!B:B=Param!B1)*(Lookup!C:C))

To translate your specific example, you would use:

=SUMPRODUCT((A1:A3=A2)*(B1:B3="B")*(C1:C3))

What is a Subclass

A sub class is a small file of a program that extends from some other class. For example you make a class about cars in general and have basic information that holds true for all cars with your constructors and stuff then you have a class that extends from that on a more specific car or line of cars that would have new variables/methods. I see you already have plenty of examples of code from above by the time I get to post this but I hope this description helps.

CATALINA_HOME environmental variable is not defined correctly

What is a Y-combinator?

If you're ready for a long read, Mike Vanier has a great explanation. Long story short, it allows you to implement recursion in a language that doesn't necessarily support it natively.

One time page refresh after first page load

Here is another solution with setTimeout, not perfect, but it works:

It requires a parameter in the current url, so just image the current url looks like this:

www.google.com?time=1

The following code make the page reload just once:

 // Reload Page Function //
    // get the time parameter //
        let parameter = new URLSearchParams(window.location.search);
          let time = parameter.get("time");
          console.log(time)//1
          let timeId;
          if (time == 1) {
    // reload the page after 0 ms //
           timeId = setTimeout(() => {
            window.location.reload();//
           }, 0);
   // change the time parameter to 0 //
           let currentUrl = new URL(window.location.href);
           let param = new URLSearchParams(currentUrl.search);
           param.set("time", 0);
   // replace the time parameter in url to 0; now it is 0 not 1 //
           window.history.replaceState({}, "", `${currentUrl.pathname}?${param}`);
        // cancel the setTimeout function after 0 ms //
           let currentTime = Date.now();
           if (Date.now() - currentTime > 0) {
            clearTimeout(timeId);
           }
          }

The accepted answer uses the least amount of code and is easy to understand. I just provided another solution to this.

Hope this helps others.

On postback, how can I check which control cause postback in Page_Init event

if (Request.Params["__EVENTTARGET"] != null)
{
  if (Request.Params["__EVENTTARGET"].ToString().Contains("myControlID"))
  {
    DoWhateverYouWant();
  }
}

How to check if "Radiobutton" is checked?

        if(jRadioButton1.isSelected()){
            jTextField1.setText("Welcome");
        }
        else if(jRadioButton2.isSelected()){
            jTextField1.setText("Hello");
        }

Relationship between hashCode and equals method in Java

Have a look at Hashtables, Hashmaps, HashSets and so forth. They all store the hashed key as their keys. When invoking get(Object key) the hash of the parameter is generated and lookup in the given hashes.

When not overwriting hashCode() and the instance of the key has been changed (for example a simple string that doesn't matter at all), the hashCode() could result in 2 different hashcodes for the same object, resulting in not finding your given key in map.get().

Last executed queries for a specific database

This works for me to find queries on any database in the instance. I'm sysadmin on the instance (check your privileges):

SELECT deqs.last_execution_time AS [Time], dest.text AS [Query], dest.*
FROM sys.dm_exec_query_stats AS deqs
CROSS APPLY sys.dm_exec_sql_text(deqs.sql_handle) AS dest
WHERE dest.dbid = DB_ID('msdb')
ORDER BY deqs.last_execution_time DESC

This is the same answer that Aaron Bertrand provided but it wasn't placed in an answer.

Checking whether a String contains a number value in Java

if(str.matches(".*\\d.*")){
   // contains a number
} else{
   // does not contain a number
}

Previous suggested solution, which does not work, but brought back because of @Eng.Fouad's request/suggestion.

Not working suggested solution

String strWithNumber = "This string has a 1 number";
String strWithoutNumber = "This string does not have a number";

System.out.println(strWithNumber.contains("\d"));
System.out.println(strWithoutNumber.contains("\d"));

Working solution

String strWithNumber = "This string has a 1 number";
if(strWithNumber.matches(".*\\d.*")){
    System.out.println("'"+strWithNumber+"' contains digit");
} else{
    System.out.println("'"+strWithNumber+"' does not contain a digit");
}

String strWithoutNumber = "This string does not have a number";
if(strWithoutNumber.matches(".*\\d.*")){
    System.out.println("'"+strWithoutNumber+"' contains digit");
} else{
    System.out.println("'"+strWithoutNumber+"' does not contain a digit");
}

Output

'This string has a 1 number' contains digit
'This string does not have a number' does not contain a digit

How to find all serial devices (ttyS, ttyUSB, ..) on Linux without opening them?

In recent kernels (not sure since when) you can list the contents of /dev/serial to get a list of the serial ports on your system. They are actually symlinks pointing to the correct /dev/ node:

flu0@laptop:~$ ls /dev/serial/
total 0
drwxr-xr-x 2 root root 60 2011-07-20 17:12 by-id/
drwxr-xr-x 2 root root 60 2011-07-20 17:12 by-path/
flu0@laptop:~$ ls /dev/serial/by-id/
total 0
lrwxrwxrwx 1 root root 13 2011-07-20 17:12 usb-Prolific_Technology_Inc._USB-Serial_Controller-if00-port0 -> ../../ttyUSB0
flu0@laptop:~$ ls /dev/serial/by-path/
total 0
lrwxrwxrwx 1 root root 13 2011-07-20 17:12 pci-0000:00:0b.0-usb-0:3:1.0-port0 -> ../../ttyUSB0

This is a USB-Serial adapter, as you can see. Note that when there are no serial ports on the system, the /dev/serial/ directory does not exists. Hope this helps :).

MySQL DAYOFWEEK() - my week begins with monday

Try to use the WEEKDAY() function.

Returns the weekday index for date (0 = Monday, 1 = Tuesday, … 6 = Sunday).

How to detect page zoom level in all modern browsers?

This answer is based on comments about devicePixelRatio coming back incorrectly on user1080381's answer.

I found that this command was coming back incorrectly in some instances too when working with a desktop, Surface Pro 3, and Surface Pro 4.

What I found is that it worked on my desktop, but the SP3 and SP4 were giving different numbers from each other and the desktop.

I noticed though that the SP3 was coming back as 1 and a half times the zoom level I was expecting. When I took a look at the display settings, the SP3 was actually set to 150% instead of the 100% I had on my desktop.

So, the solution to the comments should be to divide the returned zoom level by the scale of the machine you are currently on.

I was able to get the scale in the Windows settings by doing the following:

ManagementObjectSearcher searcher = new ManagementObjectSearcher("SELECT * FROM Win32_DesktopMonitor");
double deviceScale = Convert.ToDouble(searcher.Get().OfType<ManagementObject>().FirstOrDefault()["PixelsPerXLogicalInch"]);
int standardPixelPerInch = 96;
return deviceScale / standardPixelPerInch;

So in the case of my SP3, this is how this code looks at 100% zoom:

devicePixelRatio = 1.5
deviceScale = 144
deviceScale / standardPixelPerInch = 1.5
devicePixelRatio / (deviceScale / standardPixelPerInch) = 1

Multiplying by the 100 in user1080381's original answer then would give you a zoom of 100 (%).

Counting the occurrences / frequency of array elements

ES6 solution with reduce (fixed):

_x000D_

const arr = [2, 2, 2, 3, 2]_x000D_
_x000D_
const count = arr.reduce((pre, cur) => (cur === 2) ? ++pre : pre, 0)_x000D_
console.log(count) // 4

_x000D_

Reference - What does this error mean in PHP?

Warning: Illegal string offset 'XXX'

This happens when you try to access an array element with the square bracket syntax, but you're doing this on a string, and not on an array, so the operation clearly doesn't make sense.

Example:

$var = "test";
echo $var["a_key"];

If you think the variable should be an array, see where it comes from and fix the problem there.

JavaScript closures vs. anonymous functions

Consider the following. This creates and recreates a function f that closes on i, but different ones!:

_x000D_

i=100;_x000D_
_x000D_
f=function(i){return function(){return ++i}}(0);_x000D_
alert([f,f(),f(),f(),f(),f(),f(),f(),f(),f(),f()].join('\n\n'));_x000D_
_x000D_
f=function(i){return new Function('return ++i')}(0);        /*  function declarations ~= expressions! */_x000D_
alert([f,f(),f(),f(),f(),f(),f(),f(),f(),f(),f()].join('\n\n'));

_x000D_

while the following closes on "a" function "itself"
( themselves! the snippet after this uses a single referent f )

_x000D_

for(var i = 0; i < 10; i++) {_x000D_
    setTimeout( new Function('console.log('+i+')'),  1000 );_x000D_
}

_x000D_

or to be more explicit:

_x000D_

for(var i = 0; i < 10; i++) {_x000D_
    console.log(    f = new Function( 'console.log('+i+')' )    );_x000D_
    setTimeout( f,  1000 );_x000D_
}

_x000D_

NB. the last definition of f is function(){ console.log(9) } before 0 is printed.

Caveat! The closure concept can be a coercive distraction from the essence of elementary programming:

_x000D_

for(var i = 0; i < 10; i++) {     setTimeout( 'console.log('+i+')',  1000 );      }

_x000D_

x-refs.:
How do JavaScript closures work?
Javascript Closures Explanation
Does a (JS) Closure Require a Function Inside a Function
How to understand closures in Javascript?
Javascript local and global variable confusion

Making an svg image object clickable with onclick, avoiding absolute positioning

It worked by simply replacing the <embed/> tag with <img/> and deleting the type attribute.

For instance, in my code, instead of:

<embed src=\"./images/info_09c.svg\" type=\"image/svg+xml\" width=\"45\" onClick='afiseaza_indicatie($i, \"$indicatii[$i]\")'>

which does not answer the clicking, I wrote:

<img src=\"./images/info_09c.svg\" height=\"25\" width=\"25\" onClick='afiseaza_indicatie($i, \"$indicatii[$i]\")'>

It works in Internet Explorer and Google Chrome, and I hope that in the other browsers too.

PHP error: php_network_getaddresses: getaddrinfo failed: (while getting information from other site.)

In the following httpd.conf file, configure the ServerName properly.

/etc/httpd/conf/httpd.conf

Like below:

ServerName 127.0.0.1:80

ServerName sitename

This resolved similar issue I was facing.

How do I use grep to search the current directory for all files having the a string "hello" yet display only .h and .cc files?

grep -l hello **/*.{h,cc}

You might want to shopt -s nullglob to avoid error messages if there are no .h or no .cc files.

Webdriver Unable to connect to host 127.0.0.1 on port 7055 after 45000 ms

Update selenium jars if our selenium script is not executing. Currently i am using selenium-java-2.43.0-srcs

Now it is working fine

utf-8 special characters not displaying

set meta tag in head as

 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />

use the link http://www.i18nqa.com/debug/utf8-debug.html to replace the symbols character you want.

then use str_replace like

    $find = array('â€œ', 'â€™', 'â€¦', 'â€”', 'â€“', 'â€˜', 'Ã©', 'Â', 'â€¢', 'Ëœ', 'â€'); // en dash
                        $replace = array('“', '’', '…', '—', '–', '‘', 'é', '', '•', '˜', '”');
$content = str_replace($find, $replace, $content);

Its the method i use and help alot. Thanks!

Print a file, skipping the first X lines, in Bash

Easiest way I found to remove the first ten lines of a file:

$ sed 1,10d file.txt

In the general case (where X is the number of initial lines to delete, credit to commenters and editors for this):

$ sed 1,Xd file.txt

Why, Fatal error: Class 'PHPUnit_Framework_TestCase' not found in ...?

For those arriving here after updating phpunit to version 6 or greater released on 2017-02-03 (e.g. with composer), you may be getting this error because phpunit code is now namespaced (check changelog).

You will need to refactor things like \PHPUnit_Framework_TestCase to \PHPUnit\Framework\TestCase

How do I get IntelliJ to recognize common Python modules?

I got it to work after I unchecked the following options in the Run/Debug Configurations for main.py

Add content roots to PYTHONPATH

Add source roots to PYTHONPATH

This is after I had invalidated the cache and restarted.

Double.TryParse or Convert.ToDouble - which is faster and safer?

Personally, I find the TryParse method easier to read, which one you'll actually want to use depends on your use-case: if errors can be handled locally you are expecting errors and a bool from TryParse is good, else you might want to just let the exceptions fly.

I would expect the TryParse to be faster too, since it avoids the overhead of exception handling. But use a benchmark tool, like Jon Skeet's MiniBench to compare the various possibilities.

Set field value with reflection

You can try this:

static class Student {
    private int age;
    private int number;

    public Student(int age, int number) {
        this.age = age;
        this.number = number;
    }

    public Student() {
    }
}
public static void main(String[] args) throws IllegalAccessException, NoSuchFieldException {
    Student student1=new Student();
   // Class g=student1.getClass();
    Field[]fields=student1.getClass().getDeclaredFields();
    Field age=student1.getClass().getDeclaredField("age");
    age.setAccessible(true);
    age.setInt(student1,13);
    Field number=student1.getClass().getDeclaredField("number");
    number.setAccessible(true);
    number.setInt(student1,936);

    for (Field f:fields
         ) {
        f.setAccessible(true);

        System.out.println(f.getName()+" "+f.getInt(student1));

    }
}

}

Run Stored Procedure in SQL Developer?

Open the procedure in SQL Developer and run it from there. SQL Developer displays the SQL that it runs.

BEGIN
  PROCEEDURE_NAME_HERE();
END;

Using DISTINCT and COUNT together in a MySQL Query

SELECTING DISTINCT PRODUCT AND DISPLAY COUNT PER PRODUCT

for another answer about this type of question this is my another answer for getting count of product base on product name distinct like this sample below:

Table Value

select * FROM Product

Counted Product Name

SELECT DISTINCT(Product_Name),
(SELECT COUNT(Product_Name) 
from Product  WHERE Product_Name = Prod.Product_Name)  
as `Product_Count`
from Product as Prod

Record Count: 4; Execution Time: 2ms

Checking if a worksheet-based checkbox is checked

Is this what you are trying?

Sub Sample()
    Dim cb As Shape

    Set cb = ActiveSheet.Shapes("Check Box 1")

    If cb.OLEFormat.Object.Value = 1 Then
        MsgBox "Checkbox is Checked"
    Else
        MsgBox "Checkbox is not Checked"
    End If
End Sub

Replace Activesheet with the relevant sheetname. Also replace Check Box 1 with the relevant checkbox name.

Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed

I had the same error, then I tried <asp:PostBackTrigger ControlID="xyz"/> instead of AsyncPostBackTrigger .This worked for me. It is because we don't want a partial postback.

PHP CURL DELETE request

My own class request with wsse authentication

class Request {

    protected $_url;
    protected $_username;
    protected $_apiKey;

    public function __construct($url, $username, $apiUserKey) {
        $this->_url = $url;     
        $this->_username = $username;
        $this->_apiKey = $apiUserKey;
    }

    public function getHeader() {
        $nonce = uniqid();
        $created = date('c');
        $digest = base64_encode(sha1(base64_decode($nonce) . $created . $this->_apiKey, true));

        $wsseHeader = "Authorization: WSSE profile=\"UsernameToken\"\n";
        $wsseHeader .= sprintf(
            'X-WSSE: UsernameToken Username="%s", PasswordDigest="%s", Nonce="%s", Created="%s"', $this->_username, $digest, $nonce, $created
        );

        return $wsseHeader;
    }

    public function curl_req($path, $verb=NULL, $data=array()) {                    

        $wsseHeader[] = "Accept: application/vnd.api+json";
        $wsseHeader[] = $this->getHeader();

        $options = array(
            CURLOPT_URL => $this->_url . $path,
            CURLOPT_HTTPHEADER => $wsseHeader,
            CURLOPT_RETURNTRANSFER => true, 
            CURLOPT_HEADER => false             
        );                  

        if( !empty($data) ) {
            $options += array(
                CURLOPT_POSTFIELDS => $data,
                CURLOPT_SAFE_UPLOAD => true
            );                          
        }

        if( isset($verb) ) {
            $options += array(CURLOPT_CUSTOMREQUEST => $verb);                          
        }

        $ch = curl_init();
        curl_setopt_array($ch, $options);
        $result = curl_exec($ch);                   

        if(false === $result ) {
            echo curl_error($ch);
        }
        curl_close($ch);

        return $result; 
    }
}

How does HttpContext.Current.User.Identity.Name know which usernames exist?

Also check that

<modules>
      <remove name="FormsAuthentication"/>
</modules>

If you found anything like this just remove:

<remove name="FormsAuthentication"/>

Line from web.config and here you go it will work fine I have tested it.

Understanding unique keys for array children in React.js

I had a unique key, just had to pass it as a prop like this:

<CompName key={msg._id} message={msg} />

This page was helpful:

https://reactjs.org/docs/lists-and-keys.html#keys

Sort a Map<Key, Value> by values

The answer voted for the most does not work when you have 2 items that equals. the TreeMap leaves equal values out.

the exmaple: unsorted map

key/value: D/67.3
key/value: A/99.5
key/value: B/67.4
key/value: C/67.5
key/value: E/99.5

results

key/value: A/99.5
key/value: C/67.5
key/value: B/67.4
key/value: D/67.3

So leaves out E!!

For me it worked fine to adjust the comparator, if it equals do not return 0 but -1.

in the example:

class ValueComparator implements Comparator {

Map base; public ValueComparator(Map base) { this.base = base; }

public int compare(Object a, Object b) {
if((Double)base.get(a) < (Double)base.get(b)) {
  return 1;
} else if((Double)base.get(a) == (Double)base.get(b)) {
  return -1;
} else {
  return -1;
}
} }

now it returns:

unsorted map:

key/value: D/67.3
key/value: A/99.5
key/value: B/67.4
key/value: C/67.5
key/value: E/99.5

results:

key/value: A/99.5
key/value: E/99.5
key/value: C/67.5
key/value: B/67.4
key/value: D/67.3

as a response to Aliens (2011 nov. 22): I Am using this solution for a map of Integer Id's and names, but the idea is the same, so might be the code above is not correct (I will write it in a test and give you the correct code), this is the code for a Map sorting, based on the solution above:

package nl.iamit.util;

import java.util.Comparator;
import java.util.Map;

public class Comparators {


    public static class MapIntegerStringComparator implements Comparator {

        Map<Integer, String> base;

        public MapIntegerStringComparator(Map<Integer, String> base) {
            this.base = base;
        }

        public int compare(Object a, Object b) {

            int compare = ((String) base.get(a))
                    .compareTo((String) base.get(b));
            if (compare == 0) {
                return -1;
            }
            return compare;
        }
    }


}

and this is the test class (I just tested it, and this works for the Integer, String Map:

package test.nl.iamit.util;

import java.util.HashMap;
import java.util.TreeMap;
import nl.iamit.util.Comparators;
import org.junit.Test;
import static org.junit.Assert.assertArrayEquals;

public class TestComparators {


    @Test
    public void testMapIntegerStringComparator(){
        HashMap<Integer, String> unSoretedMap = new HashMap<Integer, String>();
        Comparators.MapIntegerStringComparator bvc = new Comparators.MapIntegerStringComparator(
                unSoretedMap);
        TreeMap<Integer, String> sorted_map = new TreeMap<Integer, String>(bvc);
        //the testdata:
        unSoretedMap.put(new Integer(1), "E");
        unSoretedMap.put(new Integer(2), "A");
        unSoretedMap.put(new Integer(3), "E");
        unSoretedMap.put(new Integer(4), "B");
        unSoretedMap.put(new Integer(5), "F");

        sorted_map.putAll(unSoretedMap);

        Object[] targetKeys={new Integer(2),new Integer(4),new Integer(3),new Integer(1),new Integer(5) };
        Object[] currecntKeys=sorted_map.keySet().toArray();

        assertArrayEquals(targetKeys,currecntKeys);
    }
}

here is the code for the Comparator of a Map:

public static class MapStringDoubleComparator implements Comparator {

    Map<String, Double> base;

    public MapStringDoubleComparator(Map<String, Double> base) {
        this.base = base;
    }

    //note if you want decending in stead of ascending, turn around 1 and -1
    public int compare(Object a, Object b) {
        if ((Double) base.get(a) == (Double) base.get(b)) {
            return 0;
        } else if((Double) base.get(a) < (Double) base.get(b)) {
            return -1;
        }else{
            return 1;
        }
    }
}

and this is the testcase for this:

@Test
public void testMapStringDoubleComparator(){
    HashMap<String, Double> unSoretedMap = new HashMap<String, Double>();
    Comparators.MapStringDoubleComparator bvc = new Comparators.MapStringDoubleComparator(
            unSoretedMap);
    TreeMap<String, Double> sorted_map = new TreeMap<String, Double>(bvc);
    //the testdata:
    unSoretedMap.put("D",new Double(67.3));
    unSoretedMap.put("A",new Double(99.5));
    unSoretedMap.put("B",new Double(67.4));
    unSoretedMap.put("C",new Double(67.5));
    unSoretedMap.put("E",new Double(99.5));

    sorted_map.putAll(unSoretedMap);

    Object[] targetKeys={"D","B","C","E","A"};
    Object[] currecntKeys=sorted_map.keySet().toArray();

    assertArrayEquals(targetKeys,currecntKeys);
}

of cource you can make this a lot more generic, but I just needed it for 1 case (the Map)

CSS to make table 100% of max-width

I have a very well working solution for tables of max-width: 100%. Just use word-break: break-all; for the table cells (except heading cells) to break all long text into several lines:

<!DOCTYPE html>
<html>
<head>
<style>

table {
  max-width: 100%; 
}
table td {
  word-break: break-all;
}

</style>
</head>
<body>

<table border="1">
  <tr>
    <th><strong>Input</strong></th>
    <th><strong>Output</strong></th>
  </tr>
  <tr>
    <td>some text</td>
    <td>12b6459fc6b4cabb4b1990be1a78e4dc5fa79c3a0fe9aa9f0386d673cfb762171a4aaa363b8dac4c33e0ad23e4830888</td>
  </tr>
</table>

</body>
</html>

This will render like this (when the screen width is limited):

How can I assign an ID to a view programmatically?

Yes, you can call setId(value) in any view with any (positive) integer value that you like and then find it in the parent container using findViewById(value). Note that it is valid to call setId() with the same value for different sibling views, but findViewById() will return only the first one.

Running multiple commands with xargs

Try this:

git config --global alias.all '!f() { find . -d -name ".git" | sed s/\\/\.git//g | xargs -P10 -I{} git --git-dir={}/.git --work-tree={} $1; }; f'

It runs ten threads in parallel and does what ever git command you want to all repos in the folder structure. No matter if the repo is one or n levels deep.

E.g: git all pull

What values for checked and selected are false?

There are no values that will cause the checkbox to be unchecked. If the checked attribute exists, the checkbox will be checked regardless of what value you set it to.

_x000D_

<input type="checkbox" checked />_x000D_
<input type="checkbox" checked="" />_x000D_
<input type="checkbox" checked="checked" />_x000D_
<input type="checkbox" checked="unchecked" />_x000D_
<input type="checkbox" checked="true" />_x000D_
<input type="checkbox" checked="false" />_x000D_
<input type="checkbox" checked="on" />_x000D_
<input type="checkbox" checked="off" />_x000D_
<input type="checkbox" checked="1" />_x000D_
<input type="checkbox" checked="0" />_x000D_
<input type="checkbox" checked="yes" />_x000D_
<input type="checkbox" checked="no" />_x000D_
<input type="checkbox" checked="y" />_x000D_
<input type="checkbox" checked="n" />

_x000D_

Renders everything checked in all modern browsers (FF3.6, Chrome 10, IE8).

What is the Record type in typescript?

A Record lets you create a new type from a Union. The values in the Union are used as attributes of the new type.

For example, say I have a Union like this:

type CatNames = "miffy" | "boris" | "mordred";

Now I want to create an object that contains information about all the cats, I can create a new type using the values in the CatName Union as keys.

type CatList = Record<CatNames, {age: number}>

If I want to satisfy this CatList, I must create an object like this:

const cats:CatList = {
  miffy: { age:99 },
  boris: { age:16 },
  mordred: { age:600 }
}

You get very strong type safety:

If I forget a cat, I get an error.
If I add a cat that's not allowed, I get an error.
If I later change CatNames, I get an error. This is especially useful because CatNames is likely imported from another file, and likely used in many places.

Real-world React example.

I used this recently to create a Status component. The component would receive a status prop, and then render an icon. I've simplified the code quite a lot here for illustrative purposes

I had a union like this:

type Statuses = "failed" | "complete";

I used this to create an object like this:

const icons: Record<
  Statuses,
  { iconType: IconTypes; iconColor: IconColors }
> = {
  failed: {
    iconType: "warning",
    iconColor: "red"
  },
  complete: {
    iconType: "check",
    iconColor: "green"
  };

I could then render by destructuring an element from the object into props, like so:

const Status = ({status}) => <Icon {...icons[status]} />

If the Statuses union is later extended or changed, I know my Status component will fail to compile and I'll get an error that I can fix immediately. This allows me to add additional error states to the app.

Note that the actual app had dozens of error states that were referenced in multiple places, so this type safety was extremely useful.

node.js: cannot find module 'request'

I had same problem, for me npm install request --save solved the problem. Hope it helps.

How to restart remote MySQL server running on Ubuntu linux?

sudo service mysql stop;
sudo service mysql start;

If the above process will not work let's check one the given code above you can stop Mysql server and again start server

Add st, nd, rd and th (ordinal) suffix to a number

I wanted to provide a functional answer to this question to complement the existing answer:

const ordinalSuffix = ['st', 'nd', 'rd']
const addSuffix = n => n + (ordinalSuffix[(n - 1) % 10] || 'th')
const numberToOrdinal = n => `${n}`.match(/1\d$/) ? n + 'th' : addSuffix(n)

we've created an array of the special values, the important thing to remember is arrays have a zero based index so ordinalSuffix[0] is equal to 'st'.

Our function numberToOrdinal checks if the number ends in a teen number in which case append the number with 'th' as all then numbers ordinals are 'th'. In the event that the number is not a teen we pass the number to addSuffix which adds the number to the ordinal which is determined by if the number minus 1 (because we're using a zero based index) mod 10 has a remainder of 2 or less it's taken from the array, otherwise it's 'th'.

sample output:

numberToOrdinal(1) // 1st
numberToOrdinal(2) // 2nd
numberToOrdinal(3) // 3rd
numberToOrdinal(4) // 4th
numberToOrdinal(5) // 5th
numberToOrdinal(6) // 6th
numberToOrdinal(7) // 7th
numberToOrdinal(8) // 8th
numberToOrdinal(9) // 9th
numberToOrdinal(10) // 10th
numberToOrdinal(11) // 11th
numberToOrdinal(12) // 12th
numberToOrdinal(13) // 13th
numberToOrdinal(14) // 14th
numberToOrdinal(101) // 101st

Ignoring directories in Git repositories on Windows

You can create the ".gitignore" file with the contents:

*
!.gitignore

It works for me.

How do I use typedef and typedef enum in C?

typedef defines a new data type. So you can have:

typedef char* my_string;
typedef struct{
  int member1;
  int member2;
} my_struct;

So now you can declare variables with these new data types

my_string s;
my_struct x;

s = "welcome";
x.member1 = 10;

For enum, things are a bit different - consider the following examples:

enum Ranks {FIRST, SECOND};
int main()
{
   int data = 20;
   if (data == FIRST)
   {
      //do something
   }
}

using typedef enum creates an alias for a type:

typedef enum Ranks {FIRST, SECOND} Order;
int main()
{
   Order data = (Order)20;  // Must cast to defined type to prevent error

   if (data == FIRST)
   {
      //do something
   }
}

Using Linq to group a list of objects into a new grouped list of list of objects

For type

public class KeyValue
{
    public string KeyCol { get; set; }
    public string ValueCol { get; set; }
}

collection

var wordList = new Model.DTO.KeyValue[] {
    new Model.DTO.KeyValue {KeyCol="key1", ValueCol="value1" },
    new Model.DTO.KeyValue {KeyCol="key2", ValueCol="value1" },
    new Model.DTO.KeyValue {KeyCol="key3", ValueCol="value2" },
    new Model.DTO.KeyValue {KeyCol="key4", ValueCol="value2" },
    new Model.DTO.KeyValue {KeyCol="key5", ValueCol="value3" },
    new Model.DTO.KeyValue {KeyCol="key6", ValueCol="value4" }
};

our linq query look like below

var query =from m in wordList group m.KeyCol by m.ValueCol into g
select new { Name = g.Key, KeyCols = g.ToList() };

or for array instead of list like below

var query =from m in wordList group m.KeyCol by m.ValueCol into g
select new { Name = g.Key, KeyCols = g.ToList().ToArray<string>() };

how to execute php code within javascript

Interaction of Javascript and PHP

We all grew up knowing that Javascript ran on the Client Side (ie the browser) and PHP was a server side tool (ie the Server side). CLEARLY the two just cant interact.

But -- good news; it can be made to work and here's how.

The objective is to get some dynamic info (say server configuration items) from the server into the Javascript environment so it can be used when needed - - typically this implies DHTML modification to the presentation.

First, to clarify the DHTML usage I'll cite this DHTML example:

<script type="text/javascript">

function updateContent() {
 var frameObj = document.getElementById("frameContent");
 var y = (frameObj.contentWindow || frameObj.contentDocument);

 if (y.document) y = y.document;
 y.body.style.backgroundColor="red";  // demonstration of failure to alter the display

 // create a default, simplistic alteration usinga fixed string.
 var textMsg = 'Say good night Gracy';

 y.write(textMsg);

 y.body.style.backgroundColor="#00ee00";  // visual confirmation that the updateContent() was effective

}
</script>

Assuming we have an html file with the ID="frameContent" somewhere, then we can alter the display with a simple < body onload="updateContent()" >

Golly gee; we don't need PHP to do that now do we! But that creates a structure for applying PHP provided content.

We change the webpage in question into a PHTML type to allow the server side PHP access to the content:

**foo.html becomes foo.phtml**

and we add to the top of that page. We also cause the php data to be loaded into globals for later access - - like this:

<?php
   global $msg1, $msg2, $textMsgPHP;

function getContent($filename) {
    if ($theData = file_get_contents($filename, FALSE)) {
        return "$theData";
    } else {
        echo "FAILED!";
        }
}
function returnContent($filename) {

  if ( $theData = getContent($filename) ) {
    // this works ONLY if $theData is one linear line (ie remove all \n)
    $textPHP = trim(preg_replace('/\r\n|\r|\n/', '', $theData));
    return "$textPHP";
  } else {
    echo '<span class="ERR">Error opening source file :(\n</span>';  # $filename!\n";
  } 
}

// preload the dynamic contents now for use later in the javascript (somewhere)
$msg1 =       returnContent('dummy_frame_data.txt');
$msg2 =       returnContent('dummy_frame_data_0.txt');
$textMsgPHP = returnContent('dummy_frame_data_1.txt');

?>

Now our javascripts can get to the PHP globals like this:

// by accessig the globals var textMsg = '< ? php global $textMsgPHP; echo "$textMsgPHP"; ? >';

In the javascript, replace

var textMsg = 'Say good night Gracy';

with: // using php returnContent()

var textMsg = '< ? php $msgX = returnContent('dummy_div_data_3.txt'); echo "$msgX" ? >';

Summary:

the webpage to be modified MUST be a phtml or some php file
the first thing in that file MUST be the < ? php to get the dynamic data ?>
the php data MUST contain its own css styling (if content is in a frame)
the javascript to use the dynamic data must be in this same file
and we drop in/outof PHP as necessary to access the dynamic data
Notice:- use single quotes in the outer javascript and ONLY double quotes in the dynamic php data

To be resolved: calling updateContent() with a filename and using it via onClick() instead of onLoad()

An example could be provided in the Sample_Dynamic_Frame.zip for your inspection, but didn't find a means to attach it

How to open mail app from Swift

For Swift 4.2+ and iOS 9+

let appURL = URL(string: "mailto:[email protected]")!

if #available(iOS 10.0, *) {
    UIApplication.shared.open(appURL, options: [:], completionHandler: nil)
} else {
    UIApplication.shared.openURL(appURL)
}

Replace [email protected] with your desired email address.

How to dispatch a Redux action with a timeout?

Why should it be so hard? It's just UI logic. Use a dedicated action to set notification data:

dispatch({ notificationData: { message: 'message', expire: +new Date() + 5*1000 } })

and a dedicated component to display it:

const Notifications = ({ notificationData }) => {
    if(notificationData.expire > this.state.currentTime) {
      return <div>{notificationData.message}</div>
    } else return null;
}

In this case the questions should be "how do you clean up old state?", "how to notify a component that time has changed"

You can implement some TIMEOUT action which is dispatched on setTimeout from a component.

Maybe it's just fine to clean it whenever a new notification is shown.

Anyway, there should be some setTimeout somewhere, right? Why not to do it in a component

setTimeout(() => this.setState({ currentTime: +new Date()}), 
           this.props.notificationData.expire-(+new Date()) )

The motivation is that the "notification fade out" functionality is really a UI concern. So it simplifies testing for your business logic.

It doesn't seem to make sense to test how it's implemented. It only makes sense to verify when the notification should time out. Thus less code to stub, faster tests, cleaner code.

No connection could be made because the target machine actively refused it 127.0.0.1

I had a similar issue, trying to run a WCF-based HttpSelfHostServer in Debug under my VisualStudio 2013. I tried every possible direction (turn off firewall, disabling IIS completely to eliminate the possibility localhost port is taken by some other service, etc.).

Eventually, what "did the trick" (solved the problem) was re-running VisualStudio 2013 as Administrator.

Amazing.

What is the different between RESTful and RESTless

'RESTless' is a term not often used.

You can define 'RESTless' as any system that is not RESTful. For that it is enough to not have one characteristic that is required for a RESTful system.

Most systems are RESTless by this definition because they don't implement HATEOAS.

How to set order of repositories in Maven settings.xml

As far as I know, the order of the repositories in your pom.xml will also decide the order of the repository access.

As for configuring repositories in settings.xml, I've read that the order of repositories is interestingly enough the inverse order of how the repositories will be accessed.

Here a post where someone explains this curiosity:
http://community.jboss.org/message/576851

Make Bootstrap Popover Appear/Disappear on Hover instead of Click

If you want to hover the popover itself as well you have to use a manual trigger.

This is what i came up with:

function enableThumbPopover() {
    var counter;

    $('.thumbcontainer').popover({
        trigger: 'manual',
        animation: false,
        html: true,
        title: function () {
            return $(this).parent().find('.thumbPopover > .title').html();
        },
        content: function () {
            return $(this).parent().find('.thumbPopover > .body').html();
        },
        container: 'body',
        placement: 'auto'
    }).on("mouseenter",function () {
        var _this = this; // thumbcontainer

        console.log('thumbcontainer mouseenter')
        // clear the counter
        clearTimeout(counter);
        // Close all other Popovers
        $('.thumbcontainer').not(_this).popover('hide');

        // start new timeout to show popover
        counter = setTimeout(function(){
            if($(_this).is(':hover'))
            {
                $(_this).popover("show");
            }
            $(".popover").on("mouseleave", function () {
                $('.thumbcontainer').popover('hide');
            });
        }, 400);

    }).on("mouseleave", function () {
        var _this = this;

        setTimeout(function () {
            if (!$(".popover:hover").length) {
                if(!$(_this).is(':hover')) // change $(this) to $(_this) 
                {
                    $(_this).popover('hide');
                }
            }
        }, 200);
    });
}

call javascript function onchange event of dropdown list

You just try this, Its so easy

 <script>

  $("#YourDropDownId").change(function () {
            alert($("#YourDropDownId").val());
        });

</script>

DataSet panel (Report Data) in SSRS designer is gone

If you are using BIDS with SQL 2008 R2 you can only get the "Report Data" menu by clicking inside the actual report layout itself.

Click inside the actual report layout.
Now select "View" from the main menu bar.
Now select "Report Data" which is the last item.

Create an array with random values

function shuffle(maxElements) {
    //create ordered array : 0,1,2,3..maxElements
    for (var temArr = [], i = 0; i < maxElements; i++) {
        temArr[i] = i;
    }

    for (var finalArr = [maxElements], i = 0; i < maxElements; i++) {
        //remove rundom element form the temArr and push it into finalArrr
        finalArr[i] = temArr.splice(Math.floor(Math.random() * (maxElements - i)), 1)[0];
    }

    return finalArr
}

I guess this method will solve the issue with the probabilities, only limited by random numbers generator.

Image resolution for mdpi, hdpi, xhdpi and xxhdpi

Check the image above I hope it will help someone.

Link to the whole article itself

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

You can do it using the Github API

This is the Python example:

import requests


if __name__ == '__main__':
    base_api_url = 'https://api.github.com/repos'
    git_repository_url = 'https://github.com/garysieling/wikipedia-categorization.git'

    github_username, repository_name = git_repository_url[:-4].split('/')[-2:]  # garysieling and wikipedia-categorization
    res = requests.get(f'{base_api_url}/{github_username}/{repository_name}')
    repository_size = res.json().get('size')
    print(repository_size)

How do I output lists as a table in Jupyter notebook?

There is a nice trick: wrap the data with pandas DataFrame.

import pandas as pd
data = [[1, 2], [3, 4]]
pd.DataFrame(data, columns=["Foo", "Bar"])

It displays data like:

  | Foo | Bar |
0 | 1   | 2   |
1 | 3   | 4   |

How to avoid installing "Unlimited Strength" JCE policy files when deploying an application?

Here's a updated version of ntoskrnl answer. It additionally contains a function to remove the final modifier like Arjan mentioned in the comments.

This version works with JRE 8u111 or newer.

private static void removeCryptographyRestrictions() {
    if (!isRestrictedCryptography()) {
        return;
    }
    try {
        /*
         * Do the following, but with reflection to bypass access checks:
         * 
         * JceSecurity.isRestricted = false; JceSecurity.defaultPolicy.perms.clear();
         * JceSecurity.defaultPolicy.add(CryptoAllPermission.INSTANCE);
         */
        final Class<?> jceSecurity = Class.forName("javax.crypto.JceSecurity");
        final Class<?> cryptoPermissions = Class.forName("javax.crypto.CryptoPermissions");
        final Class<?> cryptoAllPermission = Class.forName("javax.crypto.CryptoAllPermission");

        Field isRestrictedField = jceSecurity.getDeclaredField("isRestricted");
        isRestrictedField.setAccessible(true);
        setFinalStatic(isRestrictedField, true);
        isRestrictedField.set(null, false);

        final Field defaultPolicyField = jceSecurity.getDeclaredField("defaultPolicy");
        defaultPolicyField.setAccessible(true);
        final PermissionCollection defaultPolicy = (PermissionCollection) defaultPolicyField.get(null);

        final Field perms = cryptoPermissions.getDeclaredField("perms");
        perms.setAccessible(true);
        ((Map<?, ?>) perms.get(defaultPolicy)).clear();

        final Field instance = cryptoAllPermission.getDeclaredField("INSTANCE");
        instance.setAccessible(true);
        defaultPolicy.add((Permission) instance.get(null));
    }
    catch (final Exception e) {
        e.printStackTrace();
    }
}

static void setFinalStatic(Field field, Object newValue) throws Exception {
      field.setAccessible(true);

      Field modifiersField = Field.class.getDeclaredField("modifiers");
      modifiersField.setAccessible(true);
      modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);

      field.set(null, newValue);
   }

private static boolean isRestrictedCryptography() {
    // This simply matches the Oracle JRE, but not OpenJDK.
    return "Java(TM) SE Runtime Environment".equals(System.getProperty("java.runtime.name"));
}

What’s the best RESTful method to return total number of items in an object?

Alternative when you don't need actual items

Franci Penov's answer is certainly the best way to go so you always return items along with all additional metadata about your entities being requested. That's the way it should be done.

but sometimes returning all data doesn't make sense, because you may not need them at all. Maybe all you need is that metadata about your requested resource. Like total count or number of pages or something else. In such case you can always have URL query tell your service not to return items but rather just metadata like:

/api/members?metaonly=true
/api/members?includeitems=0

or something similar...

Java generics: multiple generic parameters?

You can follow one of the below approaches:

1) Basic, single type :

//One type
public static <T> void fill(List <T> list, T val) {

    for(int i=0; i<list.size(); i++){
        list.set(i, val);
    }

}

2) Multiple Types :

// multiple types as parameters
public static <T1, T2> String multipleTypeArgument(T1 val1, T2 val2) {

    return val1+" "+val2;

}

3) Below will raise compiler error as 'T3 is not in the listing of generic types that are used in function declaration part.

//Raised compilation error
public static <T1, T2> T3 returnTypeGeneric(T1 val1, T2 val2) {
    return 0;
}

Correct : Compiles fine

public static <T1, T2, T3> T3 returnTypeGeneric(T1 val1, T2 val2) {
    return 0;
}

Sample Class Code :

package generics.basics;

import java.util.ArrayList;
import java.util.List;

public class GenericMethods {

/*
 Declare the generic type parameter T in this method. 

 After the qualifiers public and static, you put <T> and 
 then followed it by return type, method name, and its parameters.

 Observe : type of val is 'T' and not '<T>'

 * */
//One type
public static <T> void fill(List <T> list, T val) {

    for(int i=0; i<list.size(); i++){
        list.set(i, val);
    }

}

// multiple types as parameters
public static <T1, T2> String multipleTypeArgument(T1 val1, T2 val2) {

    return val1+" "+val2;

}

/*// Q: To audience -> will this compile ? 
 * 
 * public static <T1, T2> T3 returnTypeGeneric(T1 val1, T2 val2) {

    return 0;

}*/

 public static <T1, T2, T3> T3 returnTypeGeneric(T1 val1, T2 val2) {

    return null;

}

public static void main(String[] args) {
    List<Integer> list = new ArrayList<>();
    list.add(10);
    list.add(20);
    System.out.println(list.toString());
    fill(list, 100);
    System.out.println(list.toString());

    List<String> Strlist = new ArrayList<>();
    Strlist.add("Chirag");
    Strlist.add("Nayak");
    System.out.println(Strlist.toString());
    fill(Strlist, "GOOD BOY");
    System.out.println(Strlist.toString());


    System.out.println(multipleTypeArgument("Chirag", 100));
    System.out.println(multipleTypeArgument(100,"Nayak"));

}

}

// class definition ends

Sample Output:

[10, 20]
[100, 100]
[Chirag, Nayak]
[GOOD BOY, GOOD BOY]
Chirag 100
100 Nayak

How to format date with hours, minutes and seconds when using jQuery UI Datepicker?

Using jQuery UI in combination with the excellent datetimepicker plugin from http://trentrichardson.com/examples/timepicker/

You can specify the dateFormat and timeFormat

$('#datepicker').datetimepicker({
    dateFormat: "yy-mm-dd",
    timeFormat:  "hh:mm:ss"
});

sql select with column name like

Blorgbeard had a great answer for SQL server. If you have a MySQL server like mine then the following will allow you to select the information from columns where the name is like some key phrase. You just have to substitute the table name, database name, and keyword.

SET @columnnames = (SELECT concat("`",GROUP_CONCAT(`COLUMN_NAME` SEPARATOR "`, `"),"`") 
FROM `INFORMATION_SCHEMA`.`COLUMNS` 
WHERE `TABLE_SCHEMA`='your_database' 
    AND `TABLE_NAME`='your_table'
    AND COLUMN_NAME LIKE "%keyword%");

SET @burrito = CONCAT("SELECT ",@columnnames," FROM your_table");

PREPARE result FROM @burrito;
EXECUTE result;

connecting MySQL server to NetBeans

Fist of all make sure your SQL server is running. Actually I'm working on windows and I have installed a nice tool which is called MySQL workbench (you can find it here for almost any platform ).

you can see the server is running

Thus I just create a new database to test the connection, let's call it stackoverflow, with one table called user.

SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL,ALLOW_INVALID_DATES';

DROP SCHEMA IF EXISTS `stackoverflow` ;
CREATE SCHEMA IF NOT EXISTS `stackoverflow` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci ;
USE `stackoverflow` ;

-- -----------------------------------------------------
-- Table `stackoverflow`.`user`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `stackoverflow`.`user` ;

CREATE TABLE IF NOT EXISTS `stackoverflow`.`user` (
  `iduser` INT NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(75) NOT NULL,
  `email` VARCHAR(150) NOT NULL,
  PRIMARY KEY (`iduser`),
  UNIQUE INDEX `iduser_UNIQUE` (`iduser` ASC),
  UNIQUE INDEX `email_UNIQUE` (`email` ASC))
ENGINE = InnoDB;


SET SQL_MODE=@OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;

You can reduce important part to

 CREATE SCHEMA IF NOT EXISTS `stackoverflow`

 CREATE TABLE IF NOT EXISTS `stackoverflow`.`user` (
      `iduser` INT NOT NULL AUTO_INCREMENT,
      `name` VARCHAR(75) NOT NULL,
      `email` VARCHAR(150) NOT NULL,
      PRIMARY KEY (`iduser`),
      UNIQUE INDEX `iduser_UNIQUE` (`iduser` ASC),
      UNIQUE INDEX `email_UNIQUE` (`email` ASC))

So now I have my brand new stackoverflow database. Let's connect to it throught Netbeans. Launch netbeans and go to the services panel list of connections available Now right click on databases: new connection.. Choose MySql connector, they already come packed with netbeans. Then fill in the gaps the data you need. As shown in the picture add the database name and remove from the connection url the optional parameters as l?zeroDateTimeBehaviour=convertToNull . Use the right user name and password and test the connection. data

As you can see connection is successful.

Click FINISH.

You will have your connection successfully working and available under the services.

finish

Cannot connect to the Docker daemon at unix:/var/run/docker.sock. Is the docker daemon running?

I had this problem after closing docker will pulling a container docker pull mongo. At first I was getting weird errors so I purged docker sudo apt-get purge docker.io and reinstalled sudo apt-get install docker.io... all of this did nothing. I couldn't even run the hello-world container. The correct fix for me at least was:

systemctl unmask docker.service
systemctl unmask docker.socket
systemctl start docker.service

After this I could pull mongo and run hello world.

Cheers!

What is the difference between compileSdkVersion and targetSdkVersion?

The compileSdkVersion should be newest stable version. The targetSdkVersion should be fully tested and less or equal to compileSdkVersion.

Importing text file into excel sheet

There are many ways you can import Text file to the current sheet. Here are three (including the method that you are using above)

Using a QueryTable
Open the text file in memory and then write to the current sheet and finally applying Text To Columns if required.
If you want to use the method that you are currently using then after you open the text file in a new workbook, simply copy it over to the current sheet using Cells.Copy

Using a QueryTable

Here is a simple macro that I recorded. Please amend it to suit your needs.

Sub Sample()
    With ActiveSheet.QueryTables.Add(Connection:= _
        "TEXT;C:\Sample.txt", Destination:=Range("$A$1") _
        )
        .Name = "Sample"
        .FieldNames = True
        .RowNumbers = False
        .FillAdjacentFormulas = False
        .PreserveFormatting = True
        .RefreshOnFileOpen = False
        .RefreshStyle = xlInsertDeleteCells
        .SavePassword = False
        .SaveData = True
        .AdjustColumnWidth = True
        .RefreshPeriod = 0
        .TextFilePromptOnRefresh = False
        .TextFilePlatform = 437
        .TextFileStartRow = 1
        .TextFileParseType = xlDelimited
        .TextFileTextQualifier = xlTextQualifierDoubleQuote
        .TextFileConsecutiveDelimiter = False
        .TextFileTabDelimiter = True
        .TextFileSemicolonDelimiter = False
        .TextFileCommaDelimiter = True
        .TextFileSpaceDelimiter = False
        .TextFileColumnDataTypes = Array(1, 1, 1, 1, 1, 1)
        .TextFileTrailingMinusNumbers = True
        .Refresh BackgroundQuery:=False
    End With
End Sub

Open the text file in memory

Sub Sample()
    Dim MyData As String, strData() As String

    Open "C:\Sample.txt" For Binary As #1
    MyData = Space$(LOF(1))
    Get #1, , MyData
    Close #1
    strData() = Split(MyData, vbCrLf)
End Sub

Once you have the data in the array you can export it to the current sheet.

Using the method that you are already using

Sub Sample()
    Dim wbI As Workbook, wbO As Workbook
    Dim wsI As Worksheet

    Set wbI = ThisWorkbook
    Set wsI = wbI.Sheets("Sheet1") '<~~ Sheet where you want to import

    Set wbO = Workbooks.Open("C:\Sample.txt")

    wbO.Sheets(1).Cells.Copy wsI.Cells

    wbO.Close SaveChanges:=False
End Sub

FOLLOWUP

You can use the Application.GetOpenFilename to choose the relevant file. For example...

Sub Sample()
    Dim Ret

    Ret = Application.GetOpenFilename("Prn Files (*.prn), *.prn")

    If Ret <> False Then
        With ActiveSheet.QueryTables.Add(Connection:= _
        "TEXT;" & Ret, Destination:=Range("$A$1"))

            '~~> Rest of the code

        End With
    End If
End Sub

Adding header for HttpURLConnection

Your code is fine.You can also use the same thing in this way.

public static String getResponseFromJsonURL(String url) {
    String jsonResponse = null;
    if (CommonUtility.isNotEmpty(url)) {
        try {
            /************** For getting response from HTTP URL start ***************/
            URL object = new URL(url);

            HttpURLConnection connection = (HttpURLConnection) object
                    .openConnection();
            // int timeOut = connection.getReadTimeout();
            connection.setReadTimeout(60 * 1000);
            connection.setConnectTimeout(60 * 1000);
            String authorization="xyz:xyz$123";
            String encodedAuth="Basic "+Base64.encode(authorization.getBytes());
            connection.setRequestProperty("Authorization", encodedAuth);
            int responseCode = connection.getResponseCode();
            //String responseMsg = connection.getResponseMessage();

            if (responseCode == 200) {
                InputStream inputStr = connection.getInputStream();
                String encoding = connection.getContentEncoding() == null ? "UTF-8"
                        : connection.getContentEncoding();
                jsonResponse = IOUtils.toString(inputStr, encoding);
                /************** For getting response from HTTP URL end ***************/

            }
        } catch (Exception e) {
            e.printStackTrace();

        }
    }
    return jsonResponse;
}

Its Return response code 200 if authorizationis success

How is a JavaScript hash map implemented?

While plain old JavaScript objects can be used as maps, they are usually implemented in a way to preserve insertion-order for compatibility with most browsers (see Craig Barnes's answer) and are thus not simple hash maps.

ES6 introduces proper Maps (see MDN JavaScript Map) of which the standard says:

Map object must be implemented using either hash tables or other mechanisms that, on average, provide access times that are sublinear on the number of elements in the collection.

Skip rows during csv import pandas

You can try yourself:

>>> import pandas as pd
>>> from StringIO import StringIO
>>> s = """1, 2
... 3, 4
... 5, 6"""
>>> pd.read_csv(StringIO(s), skiprows=[1], header=None)
   0  1
0  1  2
1  5  6
>>> pd.read_csv(StringIO(s), skiprows=1, header=None)
   0  1
0  3  4
1  5  6

How do servlets work? Instantiation, sessions, shared variables and multithreading

When the servlet container (like Apache Tomcat) starts up, it will read from the web.xml file (only one per application) if anything goes wrong or shows up an error at container side console, otherwise, it will deploy and load all web applications by using web.xml (so named it as deployment descriptor).

During instantiation phase of the servlet, servlet instance is ready but it cannot serve the client request because it is missing with two pieces of information:
1: context information
2: initial configuration information

Servlet engine creates servletConfig interface object encapsulating the above missing information into it servlet engine calls init() of the servlet by supplying servletConfig object references as an argument. Once init() is completely executed servlet is ready to serve the client request.

Q) In the lifetime of servlet how many times instantiation and initialization happens ??

A)only once (for every client request a new thread is created) only one instance of the servlet serves any number of the client request ie, after serving one client request server does not die. It waits for other client requests ie what CGI (for every client request a new process is created) limitation is overcome with the servlet (internally servlet engine creates the thread).

Q)How session concept works?

A)whenever getSession() is called on HttpServletRequest object

Step 1: request object is evaluated for incoming session ID.

Step 2: if ID not available a brand new HttpSession object is created and its corresponding session ID is generated (ie of HashTable) session ID is stored into httpservlet response object and the reference of HttpSession object is returned to the servlet (doGet/doPost).

Step 3: if ID available brand new session object is not created session ID is picked up from the request object search is made in the collection of sessions by using session ID as the key.

Once the search is successful session ID is stored into HttpServletResponse and the existing session object references are returned to the doGet() or doPost() of UserDefineservlet.

Note:

1)when control leaves from servlet code to client don't forget that session object is being held by servlet container ie, the servlet engine

2)multithreading is left to servlet developers people for implementing ie., handle the multiple requests of client nothing to bother about multithread code

Inshort form:

A servlet is created when the application starts (it is deployed on the servlet container) or when it is first accessed (depending on the load-on-startup setting) when the servlet is instantiated, the init() method of the servlet is called then the servlet (its one and only instance) handles all requests (its service() method being called by multiple threads). That's why it is not advisable to have any synchronization in it, and you should avoid instance variables of the servlet when the application is undeployed (the servlet container stops), the destroy() method is called.

How to secure RESTful web services?

There's another, very secure method. It's client certificates. Know how servers present an SSL Cert when you contact them on https? Well servers can request a cert from a client so they know the client is who they say they are. Clients generate certs and give them to you over a secure channel (like coming into your office with a USB key - preferably a non-trojaned USB key).

You load the ~~public key of the cert~~ client certificates (and their signer's certificate(s), if necessary) into your web server, and the web server won't accept connections from anyone except the people who have the corresponding private keys for the certs it knows about. It runs on the HTTPS layer, so you may even be able to completely skip application-level authentication like OAuth (depending on your requirements). You can abstract a layer away and create a local Certificate Authority and sign Cert Requests from clients, allowing you to skip the 'make them come into the office' and 'load certs onto the server' steps.

Pain the neck? Absolutely. Good for everything? Nope. Very secure? Yup.

It does rely on clients keeping their certificates safe however (they can't post their private keys online), and it's usually used when you sell a service to clients rather then letting anyone register and connect.

Anyway, it may not be the solution you're looking for (it probably isn't to be honest), but it's another option.

How to cast the size_t to double or int C++

You can use Boost numeric_cast.

This throws an exception if the source value is out of range of the destination type, but it doesn't detect loss of precision when converting to double.

Whatever function you use, though, you should decide what you want to happen in the case where the value in the size_t is greater than INT_MAX. If you want to detect it use numeric_cast or write your own code to check. If you somehow know that it cannot possibly happen then you could use static_cast to suppress the warning without the cost of a runtime check, but in most cases the cost doesn't matter anyway.

Retrieving the last record in each group - MySQL

Hope below Oracle query can help:

WITH Temp_table AS
(
    Select id, name, othercolumns, ROW_NUMBER() over (PARTITION BY name ORDER BY ID 
    desc)as rank from messages
)
Select id, name,othercolumns from Temp_table where rank=1

How to avoid variable substitution in Oracle SQL Developer with 'trinidad & tobago'

In SQL*Plus putting SET DEFINE ? at the top of the script will normally solve this. Might work for Oracle SQL Developer as well.

Can't subtract offset-naive and offset-aware datetimes

You don't need anything outside the std libs

datetime.datetime.now().astimezone()

If you just replace the timezone it will not adjust the time. If your system is already UTC then .replace(tz='UTC') is fine.

>>> x=datetime.datetime.now()
datetime.datetime(2020, 11, 16, 7, 57, 5, 364576)

>>> print(x)
2020-11-16 07:57:05.364576

>>> print(x.astimezone()) 
2020-11-16 07:57:05.364576-07:00

>>> print(x.replace(tzinfo=datetime.timezone.utc)) # wrong
2020-11-16 07:57:05.364576+00:00

Angular2 If ngModel is used within a form tag, either the name attribute must be set or the form

You didn't mention the version you're using, but if you're using rc5 or rc6, that "old" style of form has been deprecated. Take a look at this for guidance on the "new" forms techniques: https://angular.io/docs/ts/latest/guide/forms.html

ModuleNotFoundError: No module named 'sklearn'

Cause

Conda and pip install scikit-learn under ~/anaconda3/envs/$ENV/lib/python3.7/site-packages, however Jupyter notebook looks for the package under ~/anaconda3/lib/python3.7/site-packages.

Therefore, even when the environment is specified to conda, it does not work.

conda install -n $ENV scikit-learn # Does not work

Solution

pip 3 install the package under ~/anaconda3/lib/python3.7/site-packages.

Verify

After pip3, in a Jupyter notebook.

import sklearn
sklearn.__file__

~/anaconda3/lib/python3.7/site-packages/sklearn/init.py'

Does WGET timeout?

Prior to version 1.14, wget timeout arguments were not adhered to if downloading over https due to a bug.

Disable output buffering

def disable_stdout_buffering():
    # Appending to gc.garbage is a way to stop an object from being
    # destroyed.  If the old sys.stdout is ever collected, it will
    # close() stdout, which is not good.
    gc.garbage.append(sys.stdout)
    sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)

# Then this will give output in the correct order:
disable_stdout_buffering()
print "hello"
subprocess.call(["echo", "bye"])

Without saving the old sys.stdout, disable_stdout_buffering() isn't idempotent, and multiple calls will result in an error like this:

Traceback (most recent call last):
  File "test/buffering.py", line 17, in <module>
    print "hello"
IOError: [Errno 9] Bad file descriptor
close failed: [Errno 9] Bad file descriptor

Another possibility is:

def disable_stdout_buffering():
    fileno = sys.stdout.fileno()
    temp_fd = os.dup(fileno)
    sys.stdout.close()
    os.dup2(temp_fd, fileno)
    os.close(temp_fd)
    sys.stdout = os.fdopen(fileno, "w", 0)

(Appending to gc.garbage is not such a good idea because it's where unfreeable cycles get put, and you might want to check for those.)

MavenError: Failed to execute goal on project: Could not resolve dependencies In Maven Multimodule project

For me, adding the following block of code under <dependency management><dependencies> solved the problem.

<dependency>
    <groupId>org.glassfish</groupId>
    <artifactId>javax.el</artifactId>
    <version>3.0.1-b06</version>
</dependency>

YAML mapping values are not allowed in this context

The elements of a sequence need to be indented at the same level. Assuming you want two jobs (A and B) each with an ordered list of key value pairs, you should use:

jobs:
 - - name: A
   - schedule: "0 0/5 * 1/1 * ? *"
   - - type: mongodb.cluster
     - config:
       - host: mongodb://localhost:27017/admin?replicaSet=rs
       - minSecondaries: 2
       - minOplogHours: 100
       - maxSecondaryDelay: 120
 - - name: B
   - schedule: "0 0/5 * 1/1 * ? *"
   - - type: mongodb.cluster
     - config:
       - host: mongodb://localhost:27017/admin?replicaSet=rs
       - minSecondaries: 2
       - minOplogHours: 100
       - maxSecondaryDelay: 120

Converting the sequences of (single entry) mappings to a mapping as @Tsyvarrev does is also possible, but makes you lose the ordering.

What's the best way to use R scripts on the command line (terminal)?

#!/path/to/R won't work because R is itself a script, so execve is unhappy.

I use R --slave -f script

"rm -rf" equivalent for Windows?

You can install GnuWin32 and use *nix commands natively on windows. I install this before I install anything else on a minty fresh copy of windows. :)

groovy.lang.MissingPropertyException: No such property: jenkins for class: groovy.lang.Binding

As pointed out by @Jayan in another post, the solution was to do the following

import jenkins.model.*
jenkins = Jenkins.instance

Then I was able to do the rest of my scripting the way it was.

How to use <DllImport> in VB.NET?

I know this has already been answered, but here is an example for the people who are trying to use SQL Server Types in a vb project:

            Imports System
            Imports System.IO
            Imports System.Runtime.InteropServices

            Namespace SqlServerTypes
                Public Class Utilities



                    <DllImport("kernel32.dll", CharSet:=CharSet.Auto, SetLastError:=True)>
                    Public Shared Function LoadLibrary(ByVal libname As String) As IntPtr

                    End Function

                    Public Shared Sub LoadNativeAssemblies(ByVal rootApplicationPath As String)
                        Dim nativeBinaryPath = If(IntPtr.Size > 4, Path.Combine(rootApplicationPath, "SqlServerTypes\x64\"), Path.Combine(rootApplicationPath, "SqlServerTypes\x86\"))
                        LoadNativeAssembly(nativeBinaryPath, "msvcr120.dll")
                        LoadNativeAssembly(nativeBinaryPath, "SqlServerSpatial140.dll")
                    End Sub

                    Private Shared Sub LoadNativeAssembly(ByVal nativeBinaryPath As String, ByVal assemblyName As String)
                        Dim path = System.IO.Path.Combine(nativeBinaryPath, assemblyName)
                        Dim ptr = LoadLibrary(path)

                        If ptr = IntPtr.Zero Then
                            Throw New Exception(String.Format("Error loading {0} (ErrorCode: {1})", assemblyName, Marshal.GetLastWin32Error()))
                        End If
                    End Sub
                End Class
            End Namespace

Conditional Binding: if let error – Initializer for conditional binding must have Optional type

Well, it'd still be convenient (syntactically) if we could declare usual values inside the if's condition. So, here's a trick: you can make the compiler think there is an assignment of Optional.some(T) to a value like so:

    if let i = "abc".firstIndex(of: "a"),
        let i_int = .some(i.utf16Offset(in: "abc")),
        i_int < 1 {
        // Code
    }

Why aren't programs written in Assembly more often?

Why? Simple.

Compare this :

        for (var i = 1; i <= 100; i++)
        {
            if (i % 3 == 0)
                Console.Write("Fizz");
            if (i % 5 == 0)
                Console.Write("Buzz");
            if (i % 3 != 0 && i % 5 != 0)
                Console.Write(i);
            Console.WriteLine();
        }

with

.locals init (
    [0] int32 i)
L_0000: ldc.i4.1 
L_0001: stloc.0 
L_0002: br.s L_003b
L_0004: ldloc.0 
L_0005: ldc.i4.3 
L_0006: rem 
L_0007: brtrue.s L_0013
L_0009: ldstr "Fizz"
L_000e: call void [mscorlib]System.Console::Write(string)
L_0013: ldloc.0 
L_0014: ldc.i4.5 
L_0015: rem 
L_0016: brtrue.s L_0022
L_0018: ldstr "Buzz"
L_001d: call void [mscorlib]System.Console::Write(string)
L_0022: ldloc.0 
L_0023: ldc.i4.3 
L_0024: rem 
L_0025: brfalse.s L_0032
L_0027: ldloc.0 
L_0028: ldc.i4.5 
L_0029: rem 
L_002a: brfalse.s L_0032
L_002c: ldloc.0 
L_002d: call void [mscorlib]System.Console::Write(int32)
L_0032: call void [mscorlib]System.Console::WriteLine()
L_0037: ldloc.0 
L_0038: ldc.i4.1 
L_0039: add 
L_003a: stloc.0 
L_003b: ldloc.0 
L_003c: ldc.i4.s 100
L_003e: ble.s L_0004
L_0040: ret

They're identical feature-wise. The second one isn't even assembler but .NET IL (Intermediary Language, similar to Java's bytecode). The second compilation transforms the IL into native code (i.e. almost assembler), making it even more cryptical.

resize2fs: Bad magic number in super-block while trying to open

On Centos 7, in answer to the original question where resize2fs fails with "bad magic number" try using fsadm as follows:

fsadm resize /dev/the-device-name-returned-by-df

Then:

df

... to confirm the size changes have worked.

Easy pretty printing of floats in python?

First, elements inside a collection print their repr. you should learn about __repr__ and __str__.

This is the difference between print repr(1.1) and print 1.1. Let's join all those strings instead of the representations:

numbers = [9.0, 0.053, 0.0325754, 0.0108928, 0.0557025, 0.07933]
print "repr:", " ".join(repr(n) for n in numbers)
print "str:", " ".join(str(n) for n in numbers)

GitHub: Permission denied (publickey). fatal: The remote end hung up unexpectedly

I had to add my public key to github. https://help.github.com/articles/generating-ssh-keys

"Unable to acquire application service" error while launching Eclipse

For me, what eventually did the trick was adding -clean at the start of eclipse.ini

How to iterate through property names of Javascript object?

In JavaScript 1.8.5, Object.getOwnPropertyNames returns an array of all properties found directly upon a given object.

Object.getOwnPropertyNames ( obj )

and another method Object.keys, which returns an array containing the names of all of the given object's own enumerable properties.

Object.keys( obj )

I used forEach to list values and keys in obj, same as for (var key in obj) ..

Object.keys(obj).forEach(function (key) {
      console.log( key , obj[key] );
});

This all are new features in ECMAScript , the mothods getOwnPropertyNames, keys won't supports old browser's.

htaccess remove index.php from url

Assuming the existent url is

http://example.com/index.php/foo/bar

and we want to convert it into

 http://example.com/foo/bar

You can use the following rule :

RewriteEngine on
#1) redirect the client from "/index.php/foo/bar" to "/foo/bar"
RewriteCond %{THE_REQUEST} /index\.php/(.+)\sHTTP [NC]
RewriteRule ^ /%1 [NE,L,R]
#2)internally map "/foo/bar" to "/index.php/foo/bar"
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.+)$ /index.php/$1 [L]

In the spep #1 we first match against the request string and capture everything after the /index.php/ and the captured value is saved in %1 var. We then send the browser to a new url. The #2 processes the request internally. When the browser arrives at /foo/bar , #2rule rewrites the new url to the orignal location.

Request format is unrecognized for URL unexpectedly ending in

In html you have to enclose the call in a a form with a GET with something like

<a href="/service/servicename.asmx/FunctionName/parameter=SomeValue">label</a>

You can also use a POST with the action being the location of the web service and input the parameter via an input tag.

There are also SOAP and proxy classes.

ZIP Code (US Postal Code) validation

Are you referring to address validation? Like the previous answer by Mike, you need to cater for the othe 95%.

What you can do is when the user select's their country, then enable validation. Address validation and zipcode validation are 2 different things. Validating the ZIP is just making sure its integer. Address validation is validating the actual address for accuracy, preferably for mailing.

How to use multiprocessing pool.map with multiple arguments?

A better way is using decorator instead of writing wrapper function by hand. Especially when you have a lot of functions to map, decorator will save your time by avoiding writing wrapper for every function. Usually a decorated function is not picklable, however we may use functools to get around it. More disscusions can be found here.

Here the example

def unpack_args(func):
    from functools import wraps
    @wraps(func)
    def wrapper(args):
        if isinstance(args, dict):
            return func(**args)
        else:
            return func(*args)
    return wrapper

@unpack_args
def func(x, y):
    return x + y

Then you may map it with zipped arguments

np, xlist, ylist = 2, range(10), range(10)
pool = Pool(np)
res = pool.map(func, zip(xlist, ylist))
pool.close()
pool.join()

Of course, you may always use Pool.starmap in Python 3 (>=3.3) as mentioned in other answers.

Clear the form field after successful submission of php form

The POST data which holds the submitted form data is being echoed in the form, eg:

<input name="firstname" type="text" placeholder="First Name" required="required" 
value="<?php echo $_POST['firstname'];?>"

Either clear the POST data once you have done with the form - ie all inputs were ok and you have actioned whatever your result from a form is.
Or, once you have determined the form is ok and have actioned whatever you action from the form, redirect the user to a new page to say "all done, thanks" etc.

header('Location: thanks.php');
exit();

This stops the POST data being present, it's know as "Post/Redirect/Get":
http://en.wikipedia.org/wiki/Post/Redirect/Get

The Post/Redirect/Get (PRG) method and using another page also ensures that if users click browser refresh, or back button having navigated somewhere else, your form is not submitted again.
This means if your form inserts into a database, or emails someone (etc), without the PRG method the values will (likely) be inserted/emailed every time they click refresh or revisit the page using their history/back button.

How to decode Unicode escape sequences like "\u00ed" to proper UTF-8 encoded characters?

$str = '\u0063\u0061\u0074'.'\ud83d\ude38';
$str2 = '\u0063\u0061\u0074'.'\ud83d';

// U+1F638
var_dump(
    "cat\xF0\x9F\x98\xB8" === escape_sequence_decode($str),
    "cat\xEF\xBF\xBD" === escape_sequence_decode($str2)
);

function escape_sequence_decode($str) {

    // [U+D800 - U+DBFF][U+DC00 - U+DFFF]|[U+0000 - U+FFFF]
    $regex = '/\\\u([dD][89abAB][\da-fA-F]{2})\\\u([dD][c-fC-F][\da-fA-F]{2})
              |\\\u([\da-fA-F]{4})/sx';

    return preg_replace_callback($regex, function($matches) {

        if (isset($matches[3])) {
            $cp = hexdec($matches[3]);
        } else {
            $lead = hexdec($matches[1]);
            $trail = hexdec($matches[2]);

            // http://unicode.org/faq/utf_bom.html#utf16-4
            $cp = ($lead << 10) + $trail + 0x10000 - (0xD800 << 10) - 0xDC00;
        }

        // https://tools.ietf.org/html/rfc3629#section-3
        // Characters between U+D800 and U+DFFF are not allowed in UTF-8
        if ($cp > 0xD7FF && 0xE000 > $cp) {
            $cp = 0xFFFD;
        }

        // https://github.com/php/php-src/blob/php-5.6.4/ext/standard/html.c#L471
        // php_utf32_utf8(unsigned char *buf, unsigned k)

        if ($cp < 0x80) {
            return chr($cp);
        } else if ($cp < 0xA0) {
            return chr(0xC0 | $cp >> 6).chr(0x80 | $cp & 0x3F);
        }

        return html_entity_decode('&#'.$cp.';');
    }, $str);
}

In Python, how to check if a string only contains certain characters?

A different approach, because in my case I needed to also check whether it contained certain words (like 'test' in this example), not characters alone:

input_string = 'abc test'
input_string_test = input_string
allowed_list = ['a', 'b', 'c', 'test', ' ']

for allowed_list_item in allowed_list:
    input_string_test = input_string_test.replace(allowed_list_item, '')

if not input_string_test:
    # test passed

So, the allowed strings (char or word) are cut from the input string. If the input string only contained strings that were allowed, it should leave an empty string and therefore should pass if not input_string.

Sorting a Python list by two fields

python 3 https://docs.python.org/3.5/howto/sorting.html#the-old-way-using-the-cmp-parameter

from functools import cmp_to_key

def custom_compare(x, y):
    # custom comparsion of x[0], x[1] with y[0], y[1]
    return 0

sorted(entries, key=lambda e: (cmp_to_key(custom_compare)(e[0]), e[1]))

Escape invalid XML characters in C#

As the way to remove invalid XML characters I suggest you to use XmlConvert.IsXmlChar method. It was added since .NET Framework 4 and is presented in Silverlight too. Here is the small sample:

void Main() {
    string content = "\v\f\0";
    Console.WriteLine(IsValidXmlString(content)); // False

    content = RemoveInvalidXmlChars(content);
    Console.WriteLine(IsValidXmlString(content)); // True
}

static string RemoveInvalidXmlChars(string text) {
    var validXmlChars = text.Where(ch => XmlConvert.IsXmlChar(ch)).ToArray();
    return new string(validXmlChars);
}

static bool IsValidXmlString(string text) {
    try {
        XmlConvert.VerifyXmlChars(text);
        return true;
    } catch {
        return false;
    }
}

And as the way to escape invalid XML characters I suggest you to use XmlConvert.EncodeName method. Here is the small sample:

void Main() {
    const string content = "\v\f\0";
    Console.WriteLine(IsValidXmlString(content)); // False

    string encoded = XmlConvert.EncodeName(content);
    Console.WriteLine(IsValidXmlString(encoded)); // True

    string decoded = XmlConvert.DecodeName(encoded);
    Console.WriteLine(content == decoded); // True
}

static bool IsValidXmlString(string text) {
    try {
        XmlConvert.VerifyXmlChars(text);
        return true;
    } catch {
        return false;
    }
}

Update: It should be mentioned that the encoding operation produces a string with a length which is greater or equal than a length of a source string. It might be important when you store a encoded string in a database in a string column with length limitation and validate source string length in your app to fit data column limitation.

Android: show soft keyboard automatically when focus is on an EditText

getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);

I call this in onCreate() to show keyboard automatically, when I came in the Activity.

Java Pass Method as Parameter

Use the Observer pattern (sometimes also called Listener pattern):

interface ComponentDelegate {
    void doSomething(Component component);
}

public void setAllComponents(Component[] myComponentArray, ComponentDelegate delegate) {
    // ...
    delegate.doSomething(leaf);
}

setAllComponents(this.getComponents(), new ComponentDelegate() {
                                            void doSomething(Component component) {
                                                changeColor(component); // or do directly what you want
                                            }
                                       });

new ComponentDelegate()... declares an anonymous type implementing the interface.

Sending emails in Node.js?

npm has a few packages, but none have reached 1.0 yet. Best picks from npm list mail:

[email protected]
[email protected]
[email protected]

Schedule automatic daily upload with FileZilla

FileZilla does not have any command line arguments (nor any other way) that allow an automatic transfer.

Some references:

Though you can use any other client that allows automation.

You have not specified, what protocol you are using. FTP or SFTP? You will definitely be able to use WinSCP, as it supports all protocols that FileZilla does (and more).

Combine WinSCP scripting capabilities with Windows Scheduler:

A typical WinSCP script for upload (with SFTP) looks like:

open sftp://user:[email protected]/ -hostkey="ssh-rsa 2048 xxxxxxxxxxx...="
put c:\mypdfs\*.pdf /home/user/
close

With FTP, just replace the sftp:// with the ftp:// and remove the -hostkey="..." switch.

Similarly for download: How to schedule an automatic FTP download on Windows?

WinSCP can even generate a script from an imported FileZilla session.

For details, see the guide to FileZilla automation.

(I'm the author of WinSCP)

Another option, if you are using SFTP, is the psftp.exe client from PuTTY suite.

Tool for sending multipart/form-data request

The usual error is one tries to put Content-Type: {multipart/form-data} into the header of the post request. That will fail, it is best to let Postman do it for you. For example:

Suggestion To Load Via Postman

Fails If In Header

Works

Drawing a dot on HTML5 canvas

In my Firefox this trick works:

function SetPixel(canvas, x, y)
{
  canvas.beginPath();
  canvas.moveTo(x, y);
  canvas.lineTo(x+0.4, y+0.4);
  canvas.stroke();
}

Small offset is not visible on screen, but forces rendering engine to actually draw a point.

Content type 'application/x-www-form-urlencoded;charset=UTF-8' not supported for @RequestBody MultiValueMap

You can try to turn support on in spring's converter

@EnableWebMvc
@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        // add converter suport Content-Type: 'application/x-www-form-urlencoded'
        converters.stream()
                .filter(AllEncompassingFormHttpMessageConverter.class::isInstance)
                .map(AllEncompassingFormHttpMessageConverter.class::cast)
                .findFirst()
                .ifPresent(converter -> converter.addSupportedMediaTypes(MediaType.APPLICATION_FORM_URLENCODED_VALUE));
    }

}

PHP to write Tab Characters inside a file?

Use \t and enclose the string with double-quotes:

$chunk = "abc\tdef\tghi";

How to get Javascript Select box's selected text

Just use

$('#SelectBoxId option:selected').text(); For Getting text as listed

$('#SelectBoxId').val(); For Getting selected Index value

Mockito : doAnswer Vs thenReturn

You should use thenReturn or doReturn when you know the return value at the time you mock a method call. This defined value is returned when you invoke the mocked method.

thenReturn(T value) Sets a return value to be returned when the method is called.

@Test
public void test_return() throws Exception {
    Dummy dummy = mock(Dummy.class);
    int returnValue = 5;

    // choose your preferred way
    when(dummy.stringLength("dummy")).thenReturn(returnValue);
    doReturn(returnValue).when(dummy).stringLength("dummy");
}

Answer is used when you need to do additional actions when a mocked method is invoked, e.g. when you need to compute the return value based on the parameters of this method call.

Use doAnswer() when you want to stub a void method with generic Answer.

Answer specifies an action that is executed and a return value that is returned when you interact with the mock.

@Test
public void test_answer() throws Exception {
    Dummy dummy = mock(Dummy.class);
    Answer<Integer> answer = new Answer<Integer>() {
        public Integer answer(InvocationOnMock invocation) throws Throwable {
            String string = invocation.getArgumentAt(0, String.class);
            return string.length() * 2;
        }
    };

    // choose your preferred way
    when(dummy.stringLength("dummy")).thenAnswer(answer);
    doAnswer(answer).when(dummy).stringLength("dummy");
}

How to sort a data frame by alphabetic order of a character variable in R?

The order() function fails when the column has levels or factor. It works properly when stringsAsFactors=FALSE is used in data.frame creation.

Uninstall Node.JS using Linux command line?

Sorry the answer of George Bailey does work very fine when you want absolutely remove the node from your machine.

This answer is referred from : @tedeh https://github.com/nodesource/distributions/issues/486

If you wanna install a new version of node you have to use the code below

sudo rm -rf /var/cache/yum
sudo yum remove -y nodejs
sudo rm /etc/yum.repos.d/nodesource*
sudo yum clean all

And add new nodejs version to "yum" an new version of node

#using this command for Node version 8
curl --silent --location https://rpm.nodesource.com/setup_8.x | sudo bash -

#using this command for Node version 10
curl --silent --location https://rpm.nodesource.com/setup_10.x | sudo bash -

Install nodejs

sudo yum -y install nodejs

I hope it gonna help you guy!!!

Determine command line working directory when running node bin script

Current Working Directory

To get the current working directory, you can use:

process.cwd()

However, be aware that some scripts, notably gulp, will change the current working directory with process.chdir().

Node Module Path

You can get the path of the current module with:

__filename
__dirname

Original Directory (where the command was initiated)

If you are running a script from the command line, and you want the original directory from which the script was run, regardless of what directory the script is currently operating in, you can use:

process.env.INIT_CWD

Original directory, when working with NPM scripts

It's sometimes desirable to run an NPM script in the current directory, rather than the root of the project.

This variable is available inside npm package scripts as:

$INIT_CWD.

You must be running a recent version of NPM. If this variable is not available, make sure NPM is up to date.

This will allow you access the current path in your package.json, e.g.:

scripts: {
  "customScript": "gulp customScript --path $INIT_CWD"
}

ExtJs Gridpanel store refresh

Refresh Grid Store

Ext.getCmp('GridId').getStore().reload();

This will reload the grid store and get new data.

Java finished with non-zero exit value 2 - Android Gradle

There are two alternatives that'll work for sure:

Clean your project and then build.

If the above method didn't worked, try the next.

Add the following to build.gradle file at app level
```
defaultConfig {   

multiDexEnabled true

}
```

"Comparison method violates its general contract!"

Java does not check consistency in a strict sense, only notifies you if it runs into serious trouble. Also it does not give you much information from the error.

I was puzzled with what's happening in my sorter and made a strict consistencyChecker, maybe this will help you:

/**
 * @param dailyReports
 * @param comparator
 */
public static <T> void checkConsitency(final List<T> dailyReports, final Comparator<T> comparator) {
  final Map<T, List<T>> objectMapSmallerOnes = new HashMap<T, List<T>>();

  iterateDistinctPairs(dailyReports.iterator(), new IPairIteratorCallback<T>() {
    /**
     * @param o1
     * @param o2
     */
    @Override
    public void pair(T o1, T o2) {
      final int diff = comparator.compare(o1, o2);
      if (diff < Compare.EQUAL) {
        checkConsistency(objectMapSmallerOnes, o1, o2);
        getListSafely(objectMapSmallerOnes, o2).add(o1);
      } else if (Compare.EQUAL < diff) {
        checkConsistency(objectMapSmallerOnes, o2, o1);
        getListSafely(objectMapSmallerOnes, o1).add(o2);
      } else {
        throw new IllegalStateException("Equals not expected?");
      }
    }
  });
}

/**
 * @param objectMapSmallerOnes
 * @param o1
 * @param o2
 */
static <T> void checkConsistency(final Map<T, List<T>> objectMapSmallerOnes, T o1, T o2) {
  final List<T> smallerThan = objectMapSmallerOnes.get(o1);

  if (smallerThan != null) {
    for (final T o : smallerThan) {
      if (o == o2) {
        throw new IllegalStateException(o2 + "  cannot be smaller than " + o1 + " if it's supposed to be vice versa.");
      }
      checkConsistency(objectMapSmallerOnes, o, o2);
    }
  }
}

/**
 * @param keyMapValues 
 * @param key 
 * @param <Key> 
 * @param <Value> 
 * @return List<Value>
 */ 
public static <Key, Value> List<Value> getListSafely(Map<Key, List<Value>> keyMapValues, Key key) {
  List<Value> values = keyMapValues.get(key);

  if (values == null) {
    keyMapValues.put(key, values = new LinkedList<Value>());
  }

  return values;
}

/**
 * @author Oku
 *
 * @param <T>
 */
public interface IPairIteratorCallback<T> {
  /**
   * @param o1
   * @param o2
   */
  void pair(T o1, T o2);
}

/**
 * 
 * Iterates through each distinct unordered pair formed by the elements of a given iterator
 *
 * @param it
 * @param callback
 */
public static <T> void iterateDistinctPairs(final Iterator<T> it, IPairIteratorCallback<T> callback) {
  List<T> list = Convert.toMinimumArrayList(new Iterable<T>() {

    @Override
    public Iterator<T> iterator() {
      return it;
    }

  });

  for (int outerIndex = 0; outerIndex < list.size() - 1; outerIndex++) {
    for (int innerIndex = outerIndex + 1; innerIndex < list.size(); innerIndex++) {
      callback.pair(list.get(outerIndex), list.get(innerIndex));
    }
  }
}

Regex Last occurrence?

If you don't want to include the backslash, but only the text after it, try this: ([^\\]+)$ or for unix: ([^\/]+)$

What is a callback in java

A callback is commonly used in asynchronous programming, so you could create a method which handles the response from a web service. When you call the web service, you could pass the method to it so that when the web service responds, it call's the method you told it ... it "calls back".

In Java this can commonly be done through implementing an interface and passing an object (or an anonymous inner class) that implements it. You find this often with transactions and threading - such as the Futures API.

http://docs.oracle.com/javase/1.5.0/docs/api/java/util/concurrent/Future.html

How to get the top 10 values in postgresql?

(SELECT <some columns>
FROM mytable
<maybe some joins here>
WHERE <various conditions>
ORDER BY date DESC
LIMIT 10)

UNION ALL

(SELECT <some columns>
FROM mytable
<maybe some joins here>
WHERE <various conditions>
ORDER BY date ASC    
LIMIT 10)

How can I see if a Perl hash already has a certain key?

I guess that this code should answer your question:

use strict;
use warnings;

my @keys = qw/one two three two/;
my %hash;
for my $key (@keys)
{
    $hash{$key}++;
}

for my $key (keys %hash)
{
   print "$key: ", $hash{$key}, "\n";
}

Output:

three: 1
one: 1
two: 2

The iteration can be simplified to:

$hash{$_}++ for (@keys);

(See $_ in perlvar.) And you can even write something like this:

$hash{$_}++ or print "Found new value: $_.\n" for (@keys);

Which reports each key the first time it’s found.

Updating records codeigniter

In your Controller

public function updtitle() 
{   
    $data = array(
        'table_name' => 'your_table_name_to_update', // pass the real table name
        'id' => $this->input->post('id'),
        'title' => $this->input->post('title')
    );

    $this->load->model('Updmodel'); // load the model first
    if($this->Updmodel->upddata($data)) // call the method from the model
    {
        // update successful
    }
    else
    {
        // update not successful
    }

}

In Your Model

public function upddata($data) {
    extract($data);
    $this->db->where('emp_no', $id);
    $this->db->update($table_name, array('title' => $title));
    return true;
}

The active record query is similar to

"update $table_name set title='$title' where emp_no=$id"

How to set editable true/false EditText in Android programmatically?

editText.setFocusable(false);
editText.setClickable(false);

OnItemCLickListener not working in listview

if you have textviews, buttons or stg clickable or selectable in your row view only

android:descendantFocusability="blocksDescendants"

is not enough. You have to set

android:textIsSelectable="false"

to your textviews and

android:focusable="false"

to your buttons and other focusable items.

PHP str_replace replace spaces with underscores

Try this instead:

$journalName = preg_replace('/\s+/', '_', $journalName);

Explanation: you are most likely seeing whitespace, not just plain spaces (there is a difference).

Specified cast is not valid.. how to resolve this

Use Convert.ToDouble(value) rather than (double)value. It takes an object and supports all of the types you asked for! :)

Also, your method is always returning a string in the code above; I'd recommend having the method indicate so, and give it a more obvious name (public string FormatLargeNumber(object value))

What does %w(array) mean?

%W and %w allow you to create an Array of strings without using quotes and commas.

In HTML5, can the <header> and <footer> tags appear outside of the <body> tag?

I agree with some of the others' answers. The <head> and <header> tags have two unique and very unrelated functions. The <header> tag, if I'm not mistaken, was introduced in HTML5 and was created for increased accessibility, namely for screen readers. It's generally used to indicate the heading of your document and, in order to work appropriately and effectively, should be placed inside the <body> tag. The <head> tag, since it's origin, is used for SEO in that it constructs all of the necessary meta data and such. A valid HTML structure for your page with both tags included would be like something like this:

<!DOCTYPE html/>
<html lang="es">
    <head>
        <!--crazy meta stuff here-->
    </head>
    <body>
        <header>
            <!--Optional nav tag-->
            <nav>
            </nav>
        </header>
        <!--Body content-->
    </body>
</html>

Creating a Zoom Effect on an image on hover using CSS?

Add jQuery JavaScript library together with the jquery.zbox.css and jquery.zbox.js to your webpage.

<link rel="stylesheet" href="jquery.zbox.css">
<script src="jquery.min.js"></script>
<script src="jquery.zbox.min.js"></script>

Add a group of thumbnails with links pointing to the full sized images into the webpage.

<a class="zb" rel="group" href="1.png" title="Image 1">
  <img src="thumb1.png">
</a>
<a class="zb" rel="group" href="2.png" title="Image 2">
  <img src="thumb2.png">
</a>
<a class="zb" rel="group" href="3.png" title="Image 3">
 <img src="thumb3.png">
</a>

Call the function on document ready. That's it.

In the view source do:

$(".zb").zbox();

Convert Pandas column containing NaNs to dtype `int`

Most solutions here tell you how to use a placeholder integer to represent nulls. That approach isn't helpful if you're uncertain that integer won't show up in your source data though. My method with will format floats without their decimal values and convert nulls to None's. The result is an object datatype that will look like an integer field with null values when loaded into a CSV.

keep_df[col] = keep_df[col].apply(lambda x: None if pandas.isnull(x) else '{0:.0f}'.format(pandas.to_numeric(x)))

Int to Decimal Conversion - Insert decimal point at specified location

Declare it as a decimal which uses the int variable and divide this by 100

int number = 700
decimal correctNumber = (decimal)number / 100;

Edit: Bala was faster with his reaction

What is property in hasOwnProperty in JavaScript?

How do you get the "object reference" of an object in java when toString() and hashCode() have been overridden?

This is how I solved it:

Integer.toHexString(System.identityHashCode(object));

How can I use a C++ library from node.js?

Look at node-ffi.

node-ffi is a Node.js addon for loading and calling dynamic libraries using pure JavaScript. It can be used to create bindings to native libraries without writing any C++ code.

Highlight all occurrence of a selected word?

In Normal mode:

:set hlsearch

Then search for a pattern with the command / in Normal mode, or <Ctrl>o followed by / in Insert mode. * in Normal mode will search for the next occurrence of the word under the cursor. The hlsearch option will highlight all of them if set. # will search for the previous occurrence of the word.

To remove the highlight of the previous search:

:nohlsearch

You might wish to map :nohlsearch<CR> to some convenient key.

Check whether user has a Chrome extension installed

Your extension could interact with the website (e.g. changing variables) and your website could detect this.

But there should be a better way to do this. I wonder how Google is doing it on their extension gallery (already installed applications are marked).

Edit:

The gallery use the chrome.management.get function. Example:

chrome.management.get("mblbciejcodpealifnhfjbdlkedplodp", function(a){console.log(a);});

But you can only access the method from pages with the right permissions.

Passing Variable through JavaScript from one html page to another page

There are two pages: Pageone.html :

<script>
var hello = "hi"
location.replace("http://example.com/PageTwo.html?" + hi + "");
</script>

PageTwo.html :

<script>
var link = window.location.href;
link = link.replace("http://example.com/PageTwo.html?","");
document.write("The variable contained this content:" + link + "");
</script>

Hope it helps!

Custom CSS Scrollbar for Firefox

Since Firefox 64, is possible to use new specs for a simple Scrollbar styling (not as complete as in Chrome with vendor prefixes).

In this example is possible to see a solution that combine different rules to address both Firefox and Chrome with a similar (not equal) final result (example use your original Chrome rules):

The key rules are:

For Firefox

.scroller {
  overflow-y: scroll;
  scrollbar-color: #0A4C95 #C2D2E4;
}

For Chrome

.scroller::-webkit-scrollbar {
    width: 15px;
    height: 15px;
}

.scroller::-webkit-scrollbar-track-piece  {
    background-color: #C2D2E4;
}

.scroller::-webkit-scrollbar-thumb:vertical {
    height: 30px;
    background-color: #0A4C95;
}

Please note that respect to your solution, is possible to use also simpler Chrome rules as the following:

.scroller::-webkit-scrollbar-track  {
    background-color: #C2D2E4;
}

.scroller::-webkit-scrollbar-thumb {
    height: 30px;
    background-color: #0A4C95;
}

Finally, in order to hide arrows in scrollbars also in Firefox, currently is necessary to set it as "thin" with the following rule scrollbar-width: thin;

Call and receive output from Python script in Java?

You can include the Jython library in your Java Project. You can download the source code from the Jython project itself.

Jython does offers support for JSR-223 which basically lets you run a Python script from Java.

You can use a ScriptContext to configure where you want to send your output of the execution.

For instance, let's suppose you have the following Python script in a file named numbers.py:

for i in range(1,10):
    print(i)

So, you can run it from Java as follows:

public static void main(String[] args) throws ScriptException, IOException {

    StringWriter writer = new StringWriter(); //ouput will be stored here

    ScriptEngineManager manager = new ScriptEngineManager();
    ScriptContext context = new SimpleScriptContext();

    context.setWriter(writer); //configures output redirection
    ScriptEngine engine = manager.getEngineByName("python");
    engine.eval(new FileReader("numbers.py"), context);
    System.out.println(writer.toString()); 
}

And the output will be:

As long as your Python script is compatible with Python 2.5 you will not have any problems running this with Jython.

ShowAllData method of Worksheet class failed

AutoFilterMode will be True if engaged, regardless of whether there is actually a filter applied to a specific column or not. When this happens, ActiveSheet.ShowAllData will still run, throwing an error (because there is no actual filtering).

I had the same issue and got it working with

If (ActiveSheet.AutoFilterMode And ActiveSheet.FilterMode) Or ActiveSheet.FilterMode Then
  ActiveSheet.ShowAllData
End If

This seems to prevent ShowAllData from running when there is no actual filter applied but with AutoFilterMode turned on.

The second catch Or ActiveSheet.FilterMode should catch advanced filters

Undefined index with $_POST

Using the answer from the question above, you can safely get a value from $_POST without generating PHP notice if the key does not exists.

echo _arr($_POST, 'username', 'no username supplied');  
// will print $_POST['username'] or 'no username supplied'

Is there a list of Pytz Timezones?

They appear to be populated by the tz database time zones found here.

enter image description here

The cast to value type 'Int32' failed because the materialized value is null

I have used this code and it responds correctly, only the output value is nullable.

var packesCount = await botContext.Sales.Where(s => s.CustomerId == cust.CustomerId && s.Validated)
                                .SumAsync(s => (int?)s.PackesCount);
                            if(packesCount != null)
                            {
                                // your code
                            }
                            else
                            {
                                // your code
                            }

Activate tabpage of TabControl

tabControl1.SelectedTab = MyTab;

TypeScript error: Type 'void' is not assignable to type 'boolean'

Your code is passing a function as an argument to find. That function takes an element argument (of type Conversation) and returns void (meaning there is no return value). TypeScript describes this as (element: Conversation) => void'

What TypeScript is saying is that the find function doesn't expect to receive a function that takes a Conversation and returns void. It expects a function that takes a Conversations, a number and a Conversation array, and that this function should return a boolean.

So bottom line is that you either need to change your code to pass in the values to find correctly, or else you need to provide an overload to the definition of find in your definition file that accepts a Conversation and returns void.

C# - Substring: index and length must refer to a location within the string

Here is another suggestion. If you can prepend http:// to your url string you can do this

  string path = "http://www.example.com/aaa/bbb.jpg";
  Uri uri = new Uri(path);            
  string expectedString = 
      uri.PathAndQuery.Remove(uri.PathAndQuery.LastIndexOf("."));

How to check if a word is an English word with Python?

For a faster NLTK-based solution you could hash the set of words to avoid a linear search.

from nltk.corpus import words as nltk_words
def is_english_word(word):
    # creation of this dictionary would be done outside of 
    #     the function because you only need to do it once.
    dictionary = dict.fromkeys(nltk_words.words(), None)
    try:
        x = dictionary[word]
        return True
    except KeyError:
        return False

How to grep for contents after pattern?

You can use grep, as the other answers state. But you don't need grep, awk, sed, perl, cut, or any external tool. You can do it with pure bash.

Try this (semicolons are there to allow you to put it all on one line):

$ while read line;
  do
    if [[ "${line%%:\ *}" == "potato" ]];
    then
      echo ${line##*:\ };
    fi;
  done< file.txt

## tells bash to delete the longest match of ": " in $line from the front.

$ while read line; do echo ${line##*:\ }; done< file.txt
1234
5678
5432
4567
5432
56789

or if you wanted the key rather than the value, %% tells bash to delete the longest match of ": " in $line from the end.

$ while read line; do echo ${line%%:\ *}; done< file.txt
potato
apple
potato
grape
banana
sushi

The substring to split on is ":\ " because the space character must be escaped with the backslash.

You can find more like these at the linux documentation project.

String compare in Perl with "eq" vs "=="

First, eq is for comparing strings; == is for comparing numbers.

Even if the "if" condition is satisfied, it doesn't evaluate the "then" block.

I think your problem is that your variables don't contain what you think they do. I think your $str1 or $str2 contains something like "taste\n" or so. Check them by printing before your if: print "str1='$str1'\n";.

The trailing newline can be removed with the chomp($str1); function.

Array slices in C#

You could use the arrays CopyTo() method.

Or with LINQ you can use Skip() and Take()...

byte[] arr = {1, 2, 3, 4, 5, 6, 7, 8};
var subset = arr.Skip(2).Take(2);

Populate a datagridview with sql query results

you have to add the property Tables to the DataGridView Data Source

 dataGridView1.DataSource = table.Tables[0];

SSRS Conditional Formatting Switch or IIF

To dynamically change the color of a text box goto properties, goto font/Color and set the following expression

=SWITCH(Fields!CurrentRiskLevel.Value = "Low", "Green",
Fields!CurrentRiskLevel.Value = "Moderate", "Blue",
Fields!CurrentRiskLevel.Value = "Medium", "Yellow",
Fields!CurrentRiskLevel.Value = "High", "Orange",
Fields!CurrentRiskLevel.Value = "Very High", "Red"
)

Same way for tolerance

=SWITCH(Fields!Tolerance.Value = "Low", "Red",
Fields!Tolerance.Value = "Moderate", "Orange",
Fields!Tolerance.Value = "Medium", "Yellow",
Fields!Tolerance.Value = "High", "Blue",
Fields!Tolerance.Value = "Very High", "Green")

How to run shell script on host from docker container?

Write a simple server python server listening on a port (say 8080), bind the port -p 8080:8080 with the container, make a HTTP request to localhost:8080 to ask the python server running shell scripts with popen, run a curl or writing code to make a HTTP request curl -d '{"foo":"bar"}' localhost:8080

#!/usr/bin/python
from BaseHTTPServer import BaseHTTPRequestHandler,HTTPServer
import subprocess
import json

PORT_NUMBER = 8080

# This class will handles any incoming request from
# the browser 
class myHandler(BaseHTTPRequestHandler):
        def do_POST(self):
                content_len = int(self.headers.getheader('content-length'))
                post_body = self.rfile.read(content_len)
                self.send_response(200)
                self.end_headers()
                data = json.loads(post_body)

                # Use the post data
                cmd = "your shell cmd"
                p = subprocess.Popen(cmd, stdout=subprocess.PIPE, shell=True)
                p_status = p.wait()
                (output, err) = p.communicate()
                print "Command output : ", output
                print "Command exit status/return code : ", p_status

                self.wfile.write(cmd + "\n")
                return
try:
        # Create a web server and define the handler to manage the
        # incoming request
        server = HTTPServer(('', PORT_NUMBER), myHandler)
        print 'Started httpserver on port ' , PORT_NUMBER

        # Wait forever for incoming http requests
        server.serve_forever()

except KeyboardInterrupt:
        print '^C received, shutting down the web server'
        server.socket.close()

isset() and empty() - what to use

In your particular case: if ($var).

You need to use isset if you don't know whether the variable exists or not. Since you declared it on the very first line though, you know it exists, hence you don't need to, nay, should not use isset.

The same goes for empty, only that empty also combines a check for the truthiness of the value. empty is equivalent to !isset($var) || !$var and !empty is equivalent to isset($var) && $var, or isset($var) && $var == true.

If you only want to test a variable that should exist for truthiness, if ($var) is perfectly adequate and to the point.

What is the difference between a Shared Project and a Class Library in Visual Studio 2015?

Class library is shared compiled code.

Shared project is shared source code.

What is unit testing and how do you do it?

I find the easiest way to illustrate it is to look at some code. This getting started page on the NUnit site is a good introduction to the what and the how

http://www.nunit.org/index.php?p=quickStart&r=2.5

Is everything testable? Generally if it calculates something then yes. UI code is a whole other problem to deal with though, as simulating users clicking on buttons is tricky.

What should you test? I tend to write tests around the things I know are going to be tricky. Complicated state transitions, business critical calculations, that sort of thing. Generally I'm not too worried about testing basic input/output stuff, although the purists will doubtless say I'm wrong on that front and everything should be tested. Like so many other things, there is no right answer!

Debugging in Maven?

I use the MAVEN_OPTS option, and find it useful to set suspend to "suspend=y" as my exec:java programs tend to be small generators which are finished before I have manage to attach a debugger.... :) With suspend on it will wait for a debugger to attach before proceding.

How to Read and Write from the Serial Port

SerialPort (RS-232 Serial COM Port) in C# .NET
This article explains how to use the SerialPort class in .NET to read and write data, determine what serial ports are available on your machine, and how to send files. It even covers the pin assignments on the port itself.

Example Code:

using System;
using System.IO.Ports;
using System.Windows.Forms;

namespace SerialPortExample
{
  class SerialPortProgram
  {
    // Create the serial port with basic settings
    private SerialPort port = new SerialPort("COM1",
      9600, Parity.None, 8, StopBits.One);

    [STAThread]
    static void Main(string[] args)
    { 
      // Instatiate this class
      new SerialPortProgram();
    }

    private SerialPortProgram()
    {
      Console.WriteLine("Incoming Data:");

      // Attach a method to be called when there
      // is data waiting in the port's buffer
      port.DataReceived += new 
        SerialDataReceivedEventHandler(port_DataReceived);

      // Begin communications
      port.Open();

      // Enter an application loop to keep this thread alive
      Application.Run();
    }

    private void port_DataReceived(object sender,
      SerialDataReceivedEventArgs e)
    {
      // Show all the incoming data in the port's buffer
      Console.WriteLine(port.ReadExisting());
    }
  }
}

What IDE to use for Python?

Results

Spreadsheet version

Alternatively, in plain text: (also available as a a screenshot)

                         Bracket Matching -.  .- Line Numbering
                          Smart Indent -.  |  |  .- UML Editing / Viewing
         Source Control Integration -.  |  |  |  |  .- Code Folding
                    Error Markup -.  |  |  |  |  |  |  .- Code Templates
  Integrated Python Debugging -.  |  |  |  |  |  |  |  |  .- Unit Testing
    Multi-Language Support -.  |  |  |  |  |  |  |  |  |  |  .- GUI Designer (Qt, Eric, etc)
   Auto Code Completion -.  |  |  |  |  |  |  |  |  |  |  |  |  .- Integrated DB Support
     Commercial/Free -.  |  |  |  |  |  |  |  |  |  |  |  |  |  |  .- Refactoring
   Cross Platform -.  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |     
                  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Atom              |Y |F |Y |Y*|Y |Y |Y |Y |Y |Y |  |Y |Y |  |  |  |  |*many plugins
Editra            |Y |F |Y |Y |  |  |Y |Y |Y |Y |  |Y |  |  |  |  |  |
Emacs             |Y |F |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |  |  |  |
Eric Ide          |Y |F |Y |  |Y |Y |  |Y |  |Y |  |Y |  |Y |  |  |  |
Geany             |Y |F |Y*|Y |  |  |  |Y |Y |Y |  |Y |  |  |  |  |  |*very limited
Gedit             |Y |F |Y¹|Y |  |  |  |Y |Y |Y |  |  |Y²|  |  |  |  |¹with plugin; ²sort of
Idle              |Y |F |Y |  |Y |  |  |Y |Y |  |  |  |  |  |  |  |  |
IntelliJ          |Y |CF|Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |
JEdit             |Y |F |  |Y |  |  |  |  |Y |Y |  |Y |  |  |  |  |  |
KDevelop          |Y |F |Y*|Y |  |  |Y |Y |Y |Y |  |Y |  |  |  |  |  |*no type inference
Komodo            |Y |CF|Y |Y |Y |Y |Y |Y |Y |Y |  |Y |Y |Y |  |Y |  |
NetBeans*         |Y |F |Y |Y |Y |  |Y |Y |Y |Y |Y |Y |Y |Y |  |  |Y |*pre-v7.0
Notepad++         |W |F |Y |Y |  |Y*|Y*|Y*|Y |Y |  |Y |Y*|  |  |  |  |*with plugin
Pfaide            |W |C |Y |Y |  |  |  |Y |Y |Y |  |Y |Y |  |  |  |  |
PIDA              |LW|F |Y |Y |  |  |  |Y |Y |Y |  |Y |  |  |  |  |  |VIM based
PTVS              |W |F |Y |Y |Y |Y |Y |Y |Y |Y |  |Y |  |  |Y*|  |Y |*WPF bsed
PyCharm           |Y |CF|Y |Y*|Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |*JavaScript
PyDev (Eclipse)   |Y |F |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |  |  |  |
PyScripter        |W |F |Y |  |Y |Y |  |Y |Y |Y |  |Y |Y |Y |  |  |  |
PythonWin         |W |F |Y |  |Y |  |  |Y |Y |  |  |Y |  |  |  |  |  |
SciTE             |Y |F¹|  |Y |  |Y |  |Y |Y |Y |  |Y |Y |  |  |  |  |¹Mac version is
ScriptDev         |W |C |Y |Y |Y |Y |  |Y |Y |Y |  |Y |Y |  |  |  |  |    commercial
Spyder            |Y |F |Y |  |Y |Y |  |Y |Y |Y |  |  |  |  |  |  |  |
Sublime Text      |Y |CF|Y |Y |  |Y |Y |Y |Y |Y |  |Y |Y |Y*|  |  |  |extensible w/Python,
TextMate          |M |F |  |Y |  |  |Y |Y |Y |Y |  |Y |Y |  |  |  |  |    *PythonTestRunner
UliPad            |Y |F |Y |Y |Y |  |  |Y |Y |  |  |  |Y |Y |  |  |  |
Vim               |Y |F |Y |Y |Y |Y |Y |Y |Y |Y |  |Y |Y |Y |  |  |  |
Visual Studio     |W |CF|Y |Y |Y |Y |Y |Y |Y |Y |? |Y |? |? |Y |? |Y |
Visual Studio Code|Y |F |Y |Y |Y |Y |Y |Y |Y |Y |? |Y |? |? |? |? |Y |uses plugins
WingIde           |Y |C |Y |Y*|Y |Y |Y |Y |Y |Y |  |Y |Y |Y |  |  |  |*support for C
Zeus              |W |C |  |  |  |  |Y |Y |Y |Y |  |Y |Y |  |  |  |  |
                  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   Cross Platform -'  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |     
     Commercial/Free -'  |  |  |  |  |  |  |  |  |  |  |  |  |  |  '- Refactoring
   Auto Code Completion -'  |  |  |  |  |  |  |  |  |  |  |  |  '- Integrated DB Support
    Multi-Language Support -'  |  |  |  |  |  |  |  |  |  |  '- GUI Designer (Qt, Eric, etc)
  Integrated Python Debugging -'  |  |  |  |  |  |  |  |  '- Unit Testing
                    Error Markup -'  |  |  |  |  |  |  '- Code Templates
         Source Control Integration -'  |  |  |  |  '- Code Folding
                          Smart Indent -'  |  |  '- UML Editing / Viewing
                         Bracket Matching -'  '- Line Numbering

Acronyms used:

 L  - Linux
 W  - Windows
 M  - Mac
 C  - Commercial
 F  - Free
 CF - Commercial with Free limited edition
 ?  - To be confirmed

I don't mention basics like syntax highlighting as I expect these by default.

This is a just dry list reflecting your feedback and comments, I am not advocating any of these tools. I will keep updating this list as you keep posting your answers.

PS. Can you help me to add features of the above editors to the list (like auto-complete, debugging, etc.)?

We have a comprehensive wiki page for this question https://wiki.python.org/moin/IntegratedDevelopmentEnvironments

Submit edits to the spreadsheet

How to Install gcc 5.3 with yum on CentOS 7.2?

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