Programs & Examples On #Wolframalpha

Wolfram Alpha (also written WolframAlpha and Wolfram|Alpha) is an answer-engine developed by Wolfram Research

Javascript: Uncaught TypeError: Cannot call method 'addEventListener' of null

Move script tag at the end of BODY instead of HEAD because in current code when the script is computed html element doesn't exist in document.

Since you don't want to you jquery. Use window.onload or document.onload to execute the entire piece of code that you have in current script tag. window.onload vs document.onload

java.util.Date format SSSSSS: if not microseconds what are the last 3 digits?

tl;dr

Instant.now()
       .toString() 

2018-02-02T00:28:02.487114Z

Instant.parse(
    "2018-02-02T00:28:02.487114Z"
)

java.time

The accepted Answer by ppeterka is correct. Your abuse of the formatting pattern results in an erroneous display of data, while the internal value is always limited milliseconds.

The troublesome SimpleDateFormat and Date classes you are using are now legacy, supplanted by the java.time classes. The java.time classes handle nanoseconds resolution, much finer than the milliseconds limit of the legacy classes.

The equivalent to java.util.Date is java.time.Instant. You can even convert between them using new methods added to the old classes.

Instant instant = myJavaUtilDate.toInstant() ;

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

Capture the current moment in UTC. Java 8 captures the current moment in milliseconds, while a new Clock implementation in Java 9 captures the moment in finer granularity, typically microseconds though it depends on the capabilities of your computer hardware clock & OS & JVM implementation.

Instant instant = Instant.now() ;

Generate a String in standard ISO 8601 format.

String output = instant.toString() ;

2018-02-02T00:28:02.487114Z

To generate strings in other formats, search Stack Overflow for DateTimeFormatter, already covered many times.

To adjust into a time zone other than UTC, use ZonedDateTime.

ZonedDateTime zdt = instant.atZone( ZoneId.of( "Pacific/Auckland" ) ) ;

About java.time

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

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

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

Where to obtain the java.time classes?

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

Create Excel files from C# without office

If you're interested in making .xlsx (Office 2007 and beyond) files, you're in luck. Office 2007+ uses OpenXML which for lack of a more apt description is XML files inside of a zip named .xlsx

Take an excel file (2007+) and rename it to .zip, you can open it up and take a look. If you're using .NET 3.5 you can use the System.IO.Packaging library to manipulate the relationships & zipfile itself, and linq to xml to play with the xml (or just DOM if you're more comfortable).

Otherwise id reccomend DotNetZip, a powerfull library for manipulation of zipfiles.

OpenXMLDeveloper has lots of resources about OpenXML and you can find more there.

If you want .xls (2003 and below) you're going to have to look into 3rd party libraries or perhaps learn the file format yourself to achieve this without excel installed.

Get Date Object In UTC format in Java

In java 8 , It's really easy to get timestamp in UTC by using java 8 java.time.Instant library :

Instant.now();

That few word of code will return the UTC Timestamp.

How do I create a datetime in Python from milliseconds?

Converting millis to datetime (UTC):

import datetime
time_in_millis = 1596542285000
dt = datetime.datetime.fromtimestamp(time_in_millis / 1000.0, tz=datetime.timezone.utc)

Converting datetime to string following the RFC3339 standard (used by Open API specification):

from rfc3339 import rfc3339
converted_to_str = rfc3339(dt, utc=True, use_system_timezone=False)
# 2020-08-04T11:58:05Z

How to convert from Hex to ASCII in JavaScript?

function hex2a(hexx) {
    var hex = hexx.toString();//force conversion
    var str = '';
    for (var i = 0; (i < hex.length && hex.substr(i, 2) !== '00'); i += 2)
        str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
    return str;
}
hex2a('32343630'); // returns '2460'

Remove HTML Tags in Javascript with Regex

This is an old question, but I stumbled across it and thought I'd share the method I used:

var body = '<div id="anid">some <a href="link">text</a></div> and some more text';
var temp = document.createElement("div");
temp.innerHTML = body;
var sanitized = temp.textContent || temp.innerText;

sanitized will now contain: "some text and some more text"

Simple, no jQuery needed, and it shouldn't let you down even in more complex cases.

How to generate random number with the specific length in python

If you want it as a string (for example, a 10-digit phone number) you can use this:

n = 10
''.join(["{}".format(randint(0, 9)) for num in range(0, n)])

Getting execute permission to xp_cmdshell

I want to complete the answer from tchester.

(1) Enable the xp_cmdshell procedure:

-- To allow advanced options to be changed.
EXEC sp_configure 'show advanced options', 1
RECONFIGURE
GO

-- Enable the xp_cmdshell procedure
EXEC sp_configure 'xp_cmdshell', 1
RECONFIGURE
GO

(2) Create a login 'Domain\TestUser' (windows user) for the non-sysadmin user that has public access to the master database

(3) Grant EXEC permission on the xp_cmdshell stored procedure:

GRANT EXECUTE ON xp_cmdshell TO [Domain\TestUser]

(4) Create a proxy account that xp_cmdshell will be run under using sp_xp_cmdshell_proxy_account

EXEC sp_xp_cmdshell_proxy_account 'Domain\TestUser', 'pwd'
-- Note: pwd means windows password for [Domain\TestUser] account id on the box.
--       Don't include square brackets around Domain\TestUser.

(5) Grant control server permission to user

USE master;
GRANT CONTROL SERVER TO [Domain\TestUser]
GO

Maximum Java heap size of a 32-bit JVM on a 64-bit OS

You can ask the Java Runtime:

public class MaxMemory {
    public static void main(String[] args) {
        Runtime rt = Runtime.getRuntime();
        long totalMem = rt.totalMemory();
        long maxMem = rt.maxMemory();
        long freeMem = rt.freeMemory();
        double megs = 1048576.0;

        System.out.println ("Total Memory: " + totalMem + " (" + (totalMem/megs) + " MiB)");
        System.out.println ("Max Memory:   " + maxMem + " (" + (maxMem/megs) + " MiB)");
        System.out.println ("Free Memory:  " + freeMem + " (" + (freeMem/megs) + " MiB)");
    }
}

This will report the "Max Memory" based upon default heap allocation. So you still would need to play with -Xmx (on HotSpot). I found that running on Windows 7 Enterprise 64-bit, my 32-bit HotSpot JVM can allocate up to 1577MiB:

[C:scratch]> java -Xmx1600M MaxMemory
Error occurred during initialization of VM
Could not reserve enough space for object heap
Could not create the Java virtual machine.
[C:scratch]> java -Xmx1590M MaxMemory
Total Memory: 2031616 (1.9375 MiB)
Max Memory:   1654456320 (1577.8125 MiB)
Free Memory:  1840872 (1.75559234619 MiB)
[C:scratch]>

Whereas with a 64-bit JVM on the same OS, of course it's much higher (about 3TiB)

[C:scratch]> java -Xmx3560G MaxMemory
Error occurred during initialization of VM
Could not reserve enough space for object heap
[C:scratch]> java -Xmx3550G MaxMemory
Total Memory: 94240768 (89.875 MiB)
Max Memory:   3388252028928 (3184151.84297 MiB)
Free Memory:  93747752 (89.4048233032 MiB)
[C:scratch]>

As others have already mentioned, it depends on the OS.

  • For 32-bit Windows: it'll be <2GB (Windows internals book says 2GB for user processes)
  • For 32-bit BSD / Linux: <3GB (from the Devil Book)
  • For 32-bit MacOS X: <4GB (from Mac OS X internals book)
  • Not sure about 32-bit Solaris, try the above code and let us know.

For a 64-bit host OS, if the JVM is 32-bit, it'll still depend, most likely like above as demonstrated.

-- UPDATE 20110905: I just wanted to point out some other observations / details:

  • The hardware that I ran this on was 64-bit with 6GB of actual RAM installed. The operating system was Windows 7 Enterprise, 64-bit
  • The actual amount of Runtime.MaxMemory that can be allocated also depends on the operating system's working set. I once ran this while I also had VirtualBox running and found I could not successfully start the HotSpot JVM with -Xmx1590M and had to go smaller. This also implies that you may get more than 1590M depending upon your working set size at the time (though I still maintain it'll be under 2GiB for 32-bit because of Windows' design)

Fixing Sublime Text 2 line endings?

to chnage line endings from LF to CRLF:

open Sublime and follow the steps:-

1 press Ctrl+shift+p then install package name line unify endings

then again press Ctrl+shift+p

2 in the blank input box type "Line unify ending "

3 Hit enter twice

Sublime may freeze for sometimes and as a result will change the line endings from LF to CRLF

How to disable Excel's automatic cell reference change after copy/paste?

This macro does the whole job.

Sub Absolute_Reference_Copy_Paste()
'By changing "=" in formulas to "#" the content is no longer seen as a formula.
' C+S+e (my keyboard shortcut)

Dim Dummy As Range
Dim FirstSelection As Range
Dim SecondSelection As Range
Dim SheetFirst As Worksheet
Dim SheetSecond As Worksheet

On Error GoTo Whoa

Application.EnableEvents = False

' Set starting selection variable.
Set FirstSelection = Selection
Set SheetFirst = FirstSelection.Worksheet

' Reset the Find function so the scope of the search area is the current worksheet.
Set Dummy = Worksheets(1).Range("A1:A1").Find("Dummy", LookIn:=xlValues)

' Change "=" to "#" in selection.
Selection.Replace What:="=", Replacement:="#", LookAt:=xlPart, _
    SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, ReplaceFormat:=False

' Select the area you want to paste the formulas; must be same size as original
  selection and outside of the original selection.
Set SecondSelection = Application.InputBox("Select a range", "Obtain Range Object", Type:=8)
Set SheetSecond = SecondSelection.Worksheet

' Copy the original selection and paste it into the newly selected area. The active
  selection remains FirstSelection.
FirstSelection.Copy SecondSelection

' Restore "=" in FirstSelection.
Selection.Replace What:="#", Replacement:="=", LookAt:=xlPart, _
SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, ReplaceFormat:=False

' Select SecondSelection.
SheetSecond.Activate
SecondSelection.Select

' Restore "=" in SecondSelection.
Selection.Replace What:="#", Replacement:="=", LookAt:=xlPart, _
SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, ReplaceFormat:=False

' Return active selection to the original area: FirstSelection.
SheetFirst.Activate
FirstSelection.Select

Application.EnableEvents = True

Exit Sub

Whoa:
' If something goes wrong after "=" has been changed in FirstSelection, restore "=".
FirstSelection.Select
Selection.Replace What:="#", Replacement:="=", LookAt:=xlPart, _
    SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, ReplaceFormat:=False

End Sub

Note that you must match the size and shape of the original selection when you make your new selection.

How to identify a strong vs weak relationship on ERD?

The relationship Room to Class is considered weak (non-identifying) because the primary key components CID and DATE of entity Class doesn't contain the primary key RID of entity Room (in this case primary key of Room entity is a single component, but even if it was a composite key, one component of it also fulfills the condition).

However, for instance, in the case of the relationship Class and Class_Ins we see that is a strong (identifying) relationship because the primary key components EmpID and CID and DATE of Class_Ins contains a component of the primary key Class (in this case it contains both components CID and DATE).

Get Memory Usage in Android

Based on the previous answers and personnal experience, here is the code I use to monitor CPU use. The code of this class is written in pure Java.

import java.io.IOException;
import java.io.RandomAccessFile;

/**
 * Utilities available only on Linux Operating System.
 * 
 * <p>
 * A typical use is to assign a thread to CPU monitoring:
 * </p>
 * 
 * <pre>
 * &#064;Override
 * public void run() {
 *  while (CpuUtil.monitorCpu) {
 * 
 *      LinuxUtils linuxUtils = new LinuxUtils();
 * 
 *      int pid = android.os.Process.myPid();
 *      String cpuStat1 = linuxUtils.readSystemStat();
 *      String pidStat1 = linuxUtils.readProcessStat(pid);
 * 
 *      try {
 *          Thread.sleep(CPU_WINDOW);
 *      } catch (Exception e) {
 *      }
 * 
 *      String cpuStat2 = linuxUtils.readSystemStat();
 *      String pidStat2 = linuxUtils.readProcessStat(pid);
 * 
 *      float cpu = linuxUtils.getSystemCpuUsage(cpuStat1, cpuStat2);
 *      if (cpu &gt;= 0.0f) {
 *          _printLine(mOutput, &quot;total&quot;, Float.toString(cpu));
 *      }
 * 
 *      String[] toks = cpuStat1.split(&quot; &quot;);
 *      long cpu1 = linuxUtils.getSystemUptime(toks);
 * 
 *      toks = cpuStat2.split(&quot; &quot;);
 *      long cpu2 = linuxUtils.getSystemUptime(toks);
 * 
 *      cpu = linuxUtils.getProcessCpuUsage(pidStat1, pidStat2, cpu2 - cpu1);
 *      if (cpu &gt;= 0.0f) {
 *          _printLine(mOutput, &quot;&quot; + pid, Float.toString(cpu));
 *      }
 * 
 *      try {
 *          synchronized (this) {
 *              wait(CPU_REFRESH_RATE);
 *          }
 *      } catch (InterruptedException e) {
 *          e.printStackTrace();
 *          return;
 *      }
 *  }
 * 
 *  Log.i(&quot;THREAD CPU&quot;, &quot;Finishing&quot;);
 * }
 * </pre>
 */
public final class LinuxUtils {

    // Warning: there appears to be an issue with the column index with android linux:
    // it was observed that on most present devices there are actually
    // two spaces between the 'cpu' of the first column and the value of 
    // the next column with data. The thing is the index of the idle 
    // column should have been 4 and the first column with data should have index 1. 
    // The indexes defined below are coping with the double space situation.
    // If your file contains only one space then use index 1 and 4 instead of 2 and 5.
    // A better way to deal with this problem may be to use a split method 
    // not preserving blanks or compute an offset and add it to the indexes 1 and 4.

    private static final int FIRST_SYS_CPU_COLUMN_INDEX = 2;

    private static final int IDLE_SYS_CPU_COLUMN_INDEX = 5;

    /** Return the first line of /proc/stat or null if failed. */
    public String readSystemStat() {

        RandomAccessFile reader = null;
        String load = null;

        try {
            reader = new RandomAccessFile("/proc/stat", "r");
            load = reader.readLine();
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            Streams.close(reader);
        }

        return load;
    }

    /**
     * Compute and return the total CPU usage, in percent.
     * 
     * @param start
     *            first content of /proc/stat. Not null.
     * @param end
     *            second content of /proc/stat. Not null.
     * @return 12.7 for a CPU usage of 12.7% or -1 if the value is not
     *         available.
     * @see {@link #readSystemStat()}
     */
    public float getSystemCpuUsage(String start, String end) {
        String[] stat = start.split("\\s");
        long idle1 = getSystemIdleTime(stat);
        long up1 = getSystemUptime(stat);

        stat = end.split("\\s");
        long idle2 = getSystemIdleTime(stat);
        long up2 = getSystemUptime(stat);

        // don't know how it is possible but we should care about zero and
        // negative values.
        float cpu = -1f;
        if (idle1 >= 0 && up1 >= 0 && idle2 >= 0 && up2 >= 0) {
            if ((up2 + idle2) > (up1 + idle1) && up2 >= up1) {
                cpu = (up2 - up1) / (float) ((up2 + idle2) - (up1 + idle1));
                cpu *= 100.0f;
            }
        }

        return cpu;
    }

    /**
     * Return the sum of uptimes read from /proc/stat.
     * 
     * @param stat
     *            see {@link #readSystemStat()}
     */
    public long getSystemUptime(String[] stat) {
        /*
         * (from man/5/proc) /proc/stat kernel/system statistics. Varies with
         * architecture. Common entries include: cpu 3357 0 4313 1362393
         * 
         * The amount of time, measured in units of USER_HZ (1/100ths of a
         * second on most architectures, use sysconf(_SC_CLK_TCK) to obtain the
         * right value), that the system spent in user mode, user mode with low
         * priority (nice), system mode, and the idle task, respectively. The
         * last value should be USER_HZ times the second entry in the uptime
         * pseudo-file.
         * 
         * In Linux 2.6 this line includes three additional columns: iowait -
         * time waiting for I/O to complete (since 2.5.41); irq - time servicing
         * interrupts (since 2.6.0-test4); softirq - time servicing softirqs
         * (since 2.6.0-test4).
         * 
         * Since Linux 2.6.11, there is an eighth column, steal - stolen time,
         * which is the time spent in other operating systems when running in a
         * virtualized environment
         * 
         * Since Linux 2.6.24, there is a ninth column, guest, which is the time
         * spent running a virtual CPU for guest operating systems under the
         * control of the Linux kernel.
         */

        // with the following algorithm, we should cope with all versions and
        // probably new ones.
        long l = 0L;

        for (int i = FIRST_SYS_CPU_COLUMN_INDEX; i < stat.length; i++) {
            if (i != IDLE_SYS_CPU_COLUMN_INDEX ) { // bypass any idle mode. There is currently only one.
                try {
                    l += Long.parseLong(stat[i]);
                } catch (NumberFormatException ex) {
                    ex.printStackTrace();
                    return -1L;
                }
            }
        }

        return l;
    }

    /**
     * Return the sum of idle times read from /proc/stat.
     * 
     * @param stat
     *            see {@link #readSystemStat()}
     */
    public long getSystemIdleTime(String[] stat) {
        try {
            return Long.parseLong(stat[IDLE_SYS_CPU_COLUMN_INDEX]);
        } catch (NumberFormatException ex) {
            ex.printStackTrace();
        }

        return -1L;
    }

    /** Return the first line of /proc/pid/stat or null if failed. */
    public String readProcessStat(int pid) {

        RandomAccessFile reader = null;
        String line = null;

        try {
            reader = new RandomAccessFile("/proc/" + pid + "/stat", "r");
            line = reader.readLine();
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            Streams.close(reader);
        }

        return line;
    }

    /**
     * Compute and return the CPU usage for a process, in percent.
     * 
     * <p>
     * The parameters {@code totalCpuTime} is to be the one for the same period
     * of time delimited by {@code statStart} and {@code statEnd}.
     * </p>
     * 
     * @param start
     *            first content of /proc/pid/stat. Not null.
     * @param end
     *            second content of /proc/pid/stat. Not null.
     * @return the CPU use in percent or -1f if the stats are inverted or on
     *         error
     * @param uptime
     *            sum of user and kernel times for the entire system for the
     *            same period of time.
     * @return 12.7 for a cpu usage of 12.7% or -1 if the value is not available
     *         or an error occurred.
     * @see {@link #readProcessStat(int)}
     */
    public float getProcessCpuUsage(String start, String end, long uptime) {

        String[] stat = start.split("\\s");
        long up1 = getProcessUptime(stat);

        stat = end.split("\\s");
        long up2 = getProcessUptime(stat);

        float ret = -1f;
        if (up1 >= 0 && up2 >= up1 && uptime > 0.) {
            ret = 100.f * (up2 - up1) / (float) uptime;
        }

        return ret;
    }

    /**
     * Decode the fields of the file {@code /proc/pid/stat} and return (utime +
     * stime)
     * 
     * @param stat
     *            obtained with {@link #readProcessStat(int)}
     */
    public long getProcessUptime(String[] stat) {
        return Long.parseLong(stat[14]) + Long.parseLong(stat[15]);
    }

    /**
     * Decode the fields of the file {@code /proc/pid/stat} and return (cutime +
     * cstime)
     * 
     * @param stat
     *            obtained with {@link #readProcessStat(int)}
     */
    public long getProcessIdleTime(String[] stat) {
        return Long.parseLong(stat[16]) + Long.parseLong(stat[17]);
    }

    /**
     * Return the total CPU usage, in percent.
     * <p>
     * The call is blocking for the time specified by elapse.
     * </p>
     * 
     * @param elapse
     *            the time in milliseconds between reads.
     * @return 12.7 for a CPU usage of 12.7% or -1 if the value is not
     *         available.
     */
    public float syncGetSystemCpuUsage(long elapse) {

        String stat1 = readSystemStat();
        if (stat1 == null) {
            return -1.f;
        }

        try {
            Thread.sleep(elapse);
        } catch (Exception e) {
        }

        String stat2 = readSystemStat();
        if (stat2 == null) {
            return -1.f;
        }

        return getSystemCpuUsage(stat1, stat2);
    }

    /**
     * Return the CPU usage of a process, in percent.
     * <p>
     * The call is blocking for the time specified by elapse.
     * </p>
     * 
     * @param pid
     * @param elapse
     *            the time in milliseconds between reads.
     * @return 6.32 for a CPU usage of 6.32% or -1 if the value is not
     *         available.
     */
    public float syncGetProcessCpuUsage(int pid, long elapse) {

        String pidStat1 = readProcessStat(pid);
        String totalStat1 = readSystemStat();
        if (pidStat1 == null || totalStat1 == null) {
            return -1.f;
        }

        try {
            Thread.sleep(elapse);
        } catch (Exception e) {
            e.printStackTrace();
            return -1.f;
        }

        String pidStat2 = readProcessStat(pid);
        String totalStat2 = readSystemStat();
        if (pidStat2 == null || totalStat2 == null) {
            return -1.f;
        }

        String[] toks = totalStat1.split("\\s");
        long cpu1 = getSystemUptime(toks);

        toks = totalStat2.split("\\s");
        long cpu2 = getSystemUptime(toks);

        return getProcessCpuUsage(pidStat1, pidStat2, cpu2 - cpu1);
    }

}

There are several ways of exploiting this class. You can call either syncGetSystemCpuUsage or syncGetProcessCpuUsage but each is blocking the calling thread. Since a common issue is to monitor the total CPU usage and the CPU use of the current process at the same time, I have designed a class computing both of them. That class contains a dedicated thread. The output management is implementation specific and you need to code your own.

The class can be customized by a few means. The constant CPU_WINDOW defines the depth of a read, i.e. the number of milliseconds between readings and computing of the corresponding CPU load. CPU_REFRESH_RATE is the time between each CPU load measurement. Do not set CPU_REFRESH_RATE to 0 because it will suspend the thread after the first read.

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.OutputStream;

import android.app.Application;
import android.os.Handler;
import android.os.HandlerThread;
import android.util.Log;

import my.app.LinuxUtils;
import my.app.Streams;
import my.app.TestReport;
import my.app.Utils;

public final class CpuUtil {

    private static final int CPU_WINDOW = 1000;

    private static final int CPU_REFRESH_RATE = 100; // Warning: anything but > 0

    private static HandlerThread handlerThread;

    private static TestReport output;

    static {
        output = new TestReport();
        output.setDateFormat(Utils.getDateFormat(Utils.DATE_FORMAT_ENGLISH));
    }

    private static boolean monitorCpu;

    /**
     * Construct the class singleton. This method should be called in
     * {@link Application#onCreate()}
     * 
     * @param dir
     *            the parent directory
     * @param append
     *            mode
     */
    public static void setOutput(File dir, boolean append) {
        try {
            File file = new File(dir, "cpu.txt");
            output.setOutputStream(new FileOutputStream(file, append));
            if (!append) {
                output.println(file.getAbsolutePath());
                output.newLine(1);

                // print header
                _printLine(output, "Process", "CPU%");

                output.flush();
            }

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

    /** Start CPU monitoring */
    public static boolean startCpuMonitoring() {
        CpuUtil.monitorCpu = true;

        handlerThread = new HandlerThread("CPU monitoring"); //$NON-NLS-1$
        handlerThread.start();

        Handler handler = new Handler(handlerThread.getLooper());
        handler.post(new Runnable() {

            @Override
            public void run() {
                while (CpuUtil.monitorCpu) {

                    LinuxUtils linuxUtils = new LinuxUtils();

                    int pid = android.os.Process.myPid();
                    String cpuStat1 = linuxUtils.readSystemStat();
                    String pidStat1 = linuxUtils.readProcessStat(pid);

                    try {
                        Thread.sleep(CPU_WINDOW);
                    } catch (Exception e) {
                    }

                    String cpuStat2 = linuxUtils.readSystemStat();
                    String pidStat2 = linuxUtils.readProcessStat(pid);

                    float cpu = linuxUtils
                            .getSystemCpuUsage(cpuStat1, cpuStat2);
                    if (cpu >= 0.0f) {
                        _printLine(output, "total", Float.toString(cpu));
                    }

                    String[] toks = cpuStat1.split(" ");
                    long cpu1 = linuxUtils.getSystemUptime(toks);

                    toks = cpuStat2.split(" ");
                    long cpu2 = linuxUtils.getSystemUptime(toks);

                    cpu = linuxUtils.getProcessCpuUsage(pidStat1, pidStat2,
                            cpu2 - cpu1);
                    if (cpu >= 0.0f) {
                        _printLine(output, "" + pid, Float.toString(cpu));
                    }

                    try {
                        synchronized (this) {
                            wait(CPU_REFRESH_RATE);
                        }
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                        return;
                    }
                }

                Log.i("THREAD CPU", "Finishing");
            }

        });

        return CpuUtil.monitorCpu;
    }

    /** Stop CPU monitoring */
    public static void stopCpuMonitoring() {
        if (handlerThread != null) {
            monitorCpu = false;
            handlerThread.quit();
            handlerThread = null;
        }
    }

    /** Dispose of the object and release the resources allocated for it */
    public void dispose() {

        monitorCpu = false;

        if (output != null) {
            OutputStream os = output.getOutputStream();
            if (os != null) {
                Streams.close(os);
                output.setOutputStream(null);
            }

            output = null;
        }
    }

    private static void _printLine(TestReport output, String process, String cpu) {
        output.stampln(process + ";" + cpu);
    }

}

Get file path of image on Android

To get the path of all images in android I am using following code

public void allImages() 
{
    ContentResolver cr = getContentResolver();
    Cursor cursor;
    Uri allimagessuri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
    String selection = MediaStore.Images.Media._ID + " != 0";

    cursor = cr.query(allsongsuri, STAR, selection, null, null);

    if (cursor != null) {
        if (cursor.moveToFirst()) {
            do {

                String fullpath = cursor.getString(cursor
                        .getColumnIndex(MediaStore.Images.Media.DATA));
                Log.i("Image path ", fullpath + "");


            } while (cursor.moveToNext());
        }
        cursor.close();
    }

}

Rename Files and Directories (Add Prefix)

with Perl:

perl -e 'rename $_, "PRE_$_" for <*>'

How can I install pip on Windows?

To install pip globally on Python 2.x, easy_install appears to be the best solution as Adrián states.

However the installation instructions for pip recommend using virtualenv since every virtualenv has pip installed in it automatically. This does not require root access or modify your system Python installation.

Installing virtualenv still requires easy_install though.

2018 update:

Python 3.3+ now includes the venv module for easily creating virtual environments like so:

python3 -m venv /path/to/new/virtual/environment

See documentation for different platform methods of activating the environment after creation, but typically one of:

$ source <venv>/bin/activate 

C:\> <venv>\Scripts\activate.bat

How to add a Try/Catch to SQL Stored Procedure

See TRY...CATCH (Transact-SQL)

 CREATE PROCEDURE [dbo].[PL_GEN_PROVN_NO1]        
       @GAD_COMP_CODE  VARCHAR(2) =NULL, 
       @@voucher_no numeric =null output 
       AS         
   BEGIN  

     begin try 
         -- your proc code
     end try

     begin catch
          -- what you want to do in catch
     end catch    
  END -- proc end

Use of True, False, and None as return values in Python functions

One thing to ensure is that nothing can reassign your variable. If it is not a Boolean in the end, relying on truthiness will lead to bugs. The beauty of conditional programming in dynamically typed languages :).

The following prints "no".

x = False
if x:
    print 'yes'
else:
    print 'no'

Now let's change x.

x = 'False'

Now the statement prints "yes", because the string is truthy.

if x:
    print 'yes'
else:
    print 'no'

This statement, however, correctly outputs "no".

if x == True:
    print 'yes'
else:
    print 'no'

Javascript wait() function

You shouldn't edit it, you should completely scrap it.

Any attempt to make execution stop for a certain amount of time will lock up the browser and switch it to a Not Responding state. The only thing you can do is use setTimeout correctly.

How to automatically generate unique id in SQL like UID12345678?

Reference:https://docs.microsoft.com/en-us/sql/t-sql/functions/newid-transact-sql?view=sql-server-2017

-- Creating a table using NEWID for uniqueidentifier data type.

CREATE TABLE cust  
(  
 CustomerID uniqueidentifier NOT NULL  
   DEFAULT newid(),  
 Company varchar(30) NOT NULL,  
 ContactName varchar(60) NOT NULL,   
 Address varchar(30) NOT NULL,   
 City varchar(30) NOT NULL,  
 StateProvince varchar(10) NULL,  
 PostalCode varchar(10) NOT NULL,   
 CountryRegion varchar(20) NOT NULL,   
 Telephone varchar(15) NOT NULL,  
 Fax varchar(15) NULL  
);  
GO  
-- Inserting 5 rows into cust table.  
INSERT cust  
(CustomerID, Company, ContactName, Address, City, StateProvince,   
 PostalCode, CountryRegion, Telephone, Fax)  
VALUES  
 (NEWID(), 'Wartian Herkku', 'Pirkko Koskitalo', 'Torikatu 38', 'Oulu', NULL,  
 '90110', 'Finland', '981-443655', '981-443655')  
,(NEWID(), 'Wellington Importadora', 'Paula Parente', 'Rua do Mercado, 12', 'Resende', 'SP',  
 '08737-363', 'Brasil', '(14) 555-8122', '')  
,(NEWID(), 'Cactus Comidas para Ilevar', 'Patricio Simpson', 'Cerrito 333', 'Buenos Aires', NULL,   
 '1010', 'Argentina', '(1) 135-5555', '(1) 135-4892')  
,(NEWID(), 'Ernst Handel', 'Roland Mendel', 'Kirchgasse 6', 'Graz', NULL,  
 '8010', 'Austria', '7675-3425', '7675-3426')  
,(NEWID(), 'Maison Dewey', 'Catherine Dewey', 'Rue Joseph-Bens 532', 'Bruxelles', NULL,  
 'B-1180', 'Belgium', '(02) 201 24 67', '(02) 201 24 68');  
GO

How to round 0.745 to 0.75 using BigDecimal.ROUND_HALF_UP?

Use BigDecimal.valueOf(double d) instead of new BigDecimal(double d). The last one has precision errors by float and double.

Laravel-5 how to populate select box from database with id value and name value

I have added toArray() after pluck

$items = Item::get()->pluck('name', 'id')->toArray();

{{ Form::select('item_id', [null=>'Please Select'] + $items) }}

How to remove title bar from the android activity?

Add this two line in your style.xml

<item name="windowActionBar">false</item>
<item name="windowNoTitle">true</item>

Default background color of SVG root element

SVG 1.2 Tiny has viewport-fill I'm not sure how widely implemented this property is though as most browsers are targetting SVG 1.1 at this time. Opera implements it FWIW.

A more cross-browser solution currently would be to stick a <rect> element with width and height of 100% and fill="red" as the first child of the <svg> element, for example:

<rect width="100%" height="100%" fill="red"/>

How exactly does the android:onClick XML attribute differ from setOnClickListener?

To make your life easier and avoid the Anonymous Class in setOnClicklistener (), implement a View.OnClicklistener Interface as below:

public class YourClass extends CommonActivity implements View.OnClickListener, ...

this avoids:

btn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        yourMethod(v);
    }
});

and goes directly to:

@Override
public void onClick(View v) {
  switch (v.getId()) {
    case R.id.your_view:
      yourMethod();
      break;
  }
}

Free easy way to draw graphs and charts in C++?

Cern's ROOT produces some pretty nice stuff, I use it to display Neural Network data a lot.

Show pop-ups the most elegant way

See http://adamalbrecht.com/2013/12/12/creating-a-simple-modal-dialog-directive-in-angular-js/ for a simple way of doing modal dialog with Angular and without needing bootstrap

Edit: I've since been using ng-dialog from http://likeastore.github.io/ngDialog which is flexible and doesn't have any dependencies.

Difference between setTimeout with and without quotes and parentheses

i think the setTimeout function that you write is not being run. if you use jquery, you can make it run correctly by doing this :

    function alertMsg() {
      //your func
    }

    $(document).ready(function() {
       setTimeout(alertMsg,3000); 
       // the function you called by setTimeout must not be a string.
    });

How to get input field value using PHP

If its a get request use, $_GET['subject'] or if its a post request use, $_POST['subject']

How to remove a web site from google analytics

Update 26/03/2016:

Instead of a link in the bottom right corner of the Settings form, the delete button is moved to the top right corner, saying:

Move To Trash Can

When you click on it, it will ask you for confirmation and move it to Trash Can.

Set the value of an input field

The answer is really simple

// Your HTML text field

<input type="text" name="name" id="txt">

//Your javascript

<script type="text/javascript"> 
document.getElementById("txt").value = "My default value";
</script>

Or if you want to avoid JavaScript entirely: You can define it just using HTML

<input type="text" name="name" id="txt" value="My default value">

Change auto increment starting number?

You can also do it using phpmyadmin. Just select the table than go to actions. And change the Auto increment below table options. Don't forget to click on start Auto increment in phpmyadmin

How to make an executable JAR file?

A jar file is simply a file containing a collection of java files. To make a jar file executable, you need to specify where the main Class is in the jar file. Example code would be as follows.

public class JarExample {

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                // your logic here
            }
        });
    }
}

Compile your classes. To make a jar, you also need to create a Manifest File (MANIFEST.MF). For example,

Manifest-Version: 1.0
Main-Class: JarExample

Place the compiled output class files (JarExample.class,JarExample$1.class) and the manifest file in the same folder. In the command prompt, go to the folder where your files placed, and create the jar using jar command. For example (if you name your manifest file as jexample.mf)

jar cfm jarexample.jar jexample.mf *.class

It will create executable jarexample.jar.

SQL Server principal "dbo" does not exist,

Under Security, add the principal as a "SQL user without login", make it own the schema with the same name as the principal and then in Membership make it db_owner.

how to convert binary string to decimal?

I gathered all what others have suggested and created following function which has 3 arguments, the number and the base which that number has come from and the base which that number is going to be on:

changeBase(1101000, 2, 10) => 104

Run Code Snippet to try it yourself:

_x000D_
_x000D_
function changeBase(number, fromBase, toBase) {_x000D_
                        if (fromBase == 10)_x000D_
                            return (parseInt(number)).toString(toBase)_x000D_
                        else if (toBase == 10)_x000D_
                            return parseInt(number, fromBase);_x000D_
                        else{_x000D_
                            var numberInDecimal = parseInt(number, fromBase);_x000D_
                            return (parseInt(numberInDecimal)).toString(toBase);_x000D_
                    }_x000D_
}_x000D_
_x000D_
$("#btnConvert").click(function(){_x000D_
  var number = $("#txtNumber").val(),_x000D_
  fromBase = $("#txtFromBase").val(),_x000D_
  toBase = $("#txtToBase").val();_x000D_
  $("#lblResult").text(changeBase(number, fromBase, toBase));_x000D_
});
_x000D_
#lblResult{_x000D_
  padding: 20px;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<input id="txtNumber" type="text" placeholder="Number" />_x000D_
<input id="txtFromBase" type="text" placeholder="From Base" />_x000D_
<input id="txtToBase" type="text" placeholder="To Base" />_x000D_
<input id="btnConvert" type="button" value="Convert" />_x000D_
<span id="lblResult"></span>_x000D_
_x000D_
<p>Hint: <br />_x000D_
Try 110, 2, 10 and it will return 6; (110)<sub>2</sub> = 6<br />_x000D_
_x000D_
or 2d, 16, 10 => 45 meaning: (2d)<sub>16</sub> = 45<br />_x000D_
or 45, 10, 16 => 2d meaning: 45 = (2d)<sub>16</sub><br />_x000D_
or 2d, 2, 16 => 2d meaning: (101101)<sub>2</sub> = (2d)<sub>16</sub><br />_x000D_
</p>
_x000D_
_x000D_
_x000D_

FYI: If you want to pass 2d as hex number, you need to send it as a string so it goes like this: changeBase('2d', 16, 10)

ng-if, not equal to?

Here is a nifty solution with a filter:

app.filter('status', function() {

  var statusDict = {
    0: "No payment",
    1: "Late",
    2: "Late",
    3: "Some payment made",
    4: "Some payment made",
    5: "Some payment made",
    6: "Late and further taken out"
  };

  return function(status) {
    return statusDict[status] || 'Error';
  };
});

Markup:

<div ng-repeat="details in myDataSet">
  <p>{{ details.Name }}</p>
  <p>{{ details.DOB  }}</p>
  <p>{{ details.Payment[0].Status | status }}</p>
  <p>{{ details.Gender}}</p>
</div>

How to get ALL child controls of a Windows Forms form of a specific type (Button/Textbox)?

You can use a LINQ query to do this. This will query everything on the form that is type TextBox

var c = from controls in this.Controls.OfType<TextBox>()
              select controls;

Getting Python error "from: can't read /var/mail/Bio"

I ran into a similar error

"from: can't read /var/mail/django.test.utils"

when trying to run a command

>>> from django.test.utils import setup_test_environment
>>> setup_test_environment()

in the tutorial at https://docs.djangoproject.com/en/1.8/intro/tutorial05/

after reading the answer by Tamás I realized I was not trying this command in the python shell but in the termnial (this can happen to those new to linux)

solution was to first enter in the python shell with the command python and when you get these >>> then run any python commands

window.open with target "_blank" in Chrome

As Dennis says, you can't control how the browser chooses to handle target=_blank.

If you're wondering about the inconsistent behavior, probably it's pop-up blocking. Many browsers will forbid new windows from being opened apropos of nothing, but will allow new windows to be spawned as the eventual result of a mouse-click event.

SQL Server - SELECT FROM stored procedure

You need to declare a table type which contains the same number of columns your store procedure is returning. Data types of the columns in the table type and the columns returned by the procedures should be same

declare @MyTableType as table
(
FIRSTCOLUMN int
,.....
)  

Then you need to insert the result of your stored procedure in your table type you just defined

Insert into @MyTableType 
EXEC [dbo].[MyStoredProcedure]

In the end just select from your table type

Select * from @MyTableType

grep from tar.gz without extracting [faster one]

If this is really slow, I suspect you're dealing with a large archive file. It's going to uncompress it once to extract the file list, and then uncompress it N times--where N is the number of files in the archive--for the grep. In addition to all the uncompressing, it's going to have to scan a fair bit into the archive each time to extract each file. One of tar's biggest drawbacks is that there is no table of contents at the beginning. There's no efficient way to get information about all the files in the archive and only read that portion of the file. It essentially has to read all of the file up to the thing you're extracting every time; it can't just jump to a filename's location right away.

The easiest thing you can do to speed this up would be to uncompress the file first (gunzip file.tar.gz) and then work on the .tar file. That might help enough by itself. It's still going to loop through the entire archive N times, though.

If you really want this to be efficient, your only option is to completely extract everything in the archive before processing it. Since your problem is speed, I suspect this is a giant file that you don't want to extract first, but if you can, this will speed things up a lot:

tar zxf file.tar.gz
for f in hopefullySomeSubdir/*; do
  grep -l "string" $f
done

Note that grep -l prints the name of any matching file, quits after the first match, and is silent if there's no match. That alone will speed up the grepping portion of your command, so even if you don't have the space to extract the entire archive, grep -l will help. If the files are huge, it will help a lot.

How can I get the current screen orientation?

In some devices void onConfigurationChanged() may crash. User will use this code to get current screen orientation.

public int getScreenOrientation()
{
    Display getOrient = getActivity().getWindowManager().getDefaultDisplay();
    int orientation = Configuration.ORIENTATION_UNDEFINED;
    if(getOrient.getWidth()==getOrient.getHeight()){
        orientation = Configuration.ORIENTATION_SQUARE;
    } else{ 
        if(getOrient.getWidth() < getOrient.getHeight()){
            orientation = Configuration.ORIENTATION_PORTRAIT;
        }else { 
             orientation = Configuration.ORIENTATION_LANDSCAPE;
        }
    }
    return orientation;
}

And use

if (orientation==1)        // 1 for Configuration.ORIENTATION_PORTRAIT
{                          // 2 for Configuration.ORIENTATION_LANDSCAPE
   //your code             // 0 for Configuration.ORIENTATION_SQUARE
}

'react-scripts' is not recognized as an internal or external command

Running these commands worked for me:

npm cache clean --force
npm rebuild
npm install

How to put a jpg or png image into a button in HTML

<a href="#">
        <img src="p.png"></img>
    </a>

Scp command syntax for copying a folder from local machine to a remote server

scp -r C:/site user@server_ip:path

path is the place, where site will be copied into the remote server


EDIT: As I said in my comment, try pscp, as you want to use scp using PuTTY.

The other option is WinSCP

how to set value of a input hidden field through javascript?

It seems to work fine in Google Chrome. Which browser are you using? Here the proof http://jsfiddle.net/CN8XL/

Anyhow you can also access to the input value parameter through the document.FormName.checkyear.value. You have to wrap in the input in a <form> tag like with the proper name attribute, like shown below:

<form name="FormName">
    <input type="hidden" name="checkyear" id="checkyear" value="">
</form>

Have you considered using the jQuery Library? Here are the docs for .val() function.

javax.xml.bind.UnmarshalException: unexpected element. Expected elements are (none)

One of the reasons for this error is the use of the jaxb implementation from the jdk. I am not sure why such a problem can appear in pretty simple xml parsing situations. You may use the latest version of the jaxb library from a public maven repository:

http://mvnrepository.com

<dependency>
    <groupId>javax.xml.bind</groupId>
    <artifactId>jaxb-api</artifactId>
    <version>2.2.12</version>
</dependency>

Setting an int to Infinity in C++

int min and max values

Int -2,147,483,648 / 2,147,483,647 Int 64 -9,223,372,036,854,775,808 / 9,223,372,036,854,775,807

i guess you could set a to equal 9,223,372,036,854,775,807 but it would need to be an int64

if you always want a to be grater that b why do you need to check it? just set it to be true always

Create a day-of-week column in a Pandas dataframe using Python

df =df['Date'].dt.dayofweek

dayofweek is in numeric format

How to update std::map after using the find method?

std::map::find returns an iterator to the found element (or to the end() if the element was not found). So long as the map is not const, you can modify the element pointed to by the iterator:

std::map<char, int> m;
m.insert(std::make_pair('c', 0));  // c is for cookie

std::map<char, int>::iterator it = m.find('c'); 
if (it != m.end())
    it->second = 42;

ERROR Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies

If you are working with Source safe then make a new directory and take the latest there, this solved my issue...thanks

How do I write a custom init for a UIView subclass in Swift?

I create a common init for the designated and required. For convenience inits I delegate to init(frame:) with frame of zero.

Having zero frame is not a problem because typically the view is inside a ViewController's view; your custom view will get a good, safe chance to layout its subviews when its superview calls layoutSubviews() or updateConstraints(). These two functions are called by the system recursively throughout the view hierarchy. You can use either updateContstraints() or layoutSubviews(). updateContstraints() is called first, then layoutSubviews(). In updateConstraints() make sure to call super last. In layoutSubviews(), call super first.

Here's what I do:

@IBDesignable
class MyView: UIView {

      convenience init(args: Whatever) {
          self.init(frame: CGRect.zero)
          //assign custom vars
      }

      override init(frame: CGRect) {
           super.init(frame: frame)
           commonInit()
      }

      required init?(coder aDecoder: NSCoder) {
           super.init(coder: aDecoder)
           commonInit()
      }

      override func prepareForInterfaceBuilder() {
           super.prepareForInterfaceBuilder()
           commonInit()
      }

      private func commonInit() {
           //custom initialization
      }

      override func updateConstraints() {
           //set subview constraints here
           super.updateConstraints()
      }

      override func layoutSubviews() {
           super.layoutSubviews()
           //manually set subview frames here
      }

}

Error: Uncaught SyntaxError: Unexpected token <

I had the exact same symptom, and this was my problem, very tricky to track down, so I hope it helps someone.

I was using JQuery parseJSON() and the content I was attempting to parse was actually not JSON, but an error page that was being returned.

Sending arrays with Intent.putExtra

This code sends array of integer values

Initialize array List

List<Integer> test = new ArrayList<Integer>();

Add values to array List

test.add(1);
test.add(2);
test.add(3);
Intent intent=new Intent(this, targetActivty.class);

Send the array list values to target activity

intent.putIntegerArrayListExtra("test", (ArrayList<Integer>) test);
startActivity(intent);

here you get values on targetActivty

Intent intent=getIntent();
ArrayList<String> test = intent.getStringArrayListExtra("test");

Understanding the set() function

As an unordered collection type, set([8, 1, 6]) is equivalent to set([1, 6, 8]).

While it might be nicer to display the set contents in sorted order, that would make the repr() call more expensive.

Internally, the set type is implemented using a hash table: a hash function is used to separate items into a number of buckets to reduce the number of equality operations needed to check if an item is part of the set.

To produce the repr() output it just outputs the items from each bucket in turn, which is unlikely to be the sorted order.

How to list all users in a Linux group?

lid -g groupname | cut -f1 -d'(' 

How do I copy the contents of one stream to another?

From .NET 4.5 on, there is the Stream.CopyToAsync method

input.CopyToAsync(output);

This will return a Task that can be continued on when completed, like so:

await input.CopyToAsync(output)

// Code from here on will be run in a continuation.

Note that depending on where the call to CopyToAsync is made, the code that follows may or may not continue on the same thread that called it.

The SynchronizationContext that was captured when calling await will determine what thread the continuation will be executed on.

Additionally, this call (and this is an implementation detail subject to change) still sequences reads and writes (it just doesn't waste a threads blocking on I/O completion).

From .NET 4.0 on, there's is the Stream.CopyTo method

input.CopyTo(output);

For .NET 3.5 and before

There isn't anything baked into the framework to assist with this; you have to copy the content manually, like so:

public static void CopyStream(Stream input, Stream output)
{
    byte[] buffer = new byte[32768];
    int read;
    while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
    {
        output.Write (buffer, 0, read);
    }
}

Note 1: This method will allow you to report on progress (x bytes read so far ...)
Note 2: Why use a fixed buffer size and not input.Length? Because that Length may not be available! From the docs:

If a class derived from Stream does not support seeking, calls to Length, SetLength, Position, and Seek throw a NotSupportedException.

How to generate components in a specific folder with Angular CLI?

I wasn't having any luck with the above answers (including --flat), but what worked for me was:

cd path/to/specific/directory

From there, I ran the ng g c mynewcomponent

Xcode Product -> Archive disabled

Select active scheme to Generic iOs Device.

select to Generic iOs Device

How to undo a git pull?

Find the <SHA#> for the commit you want to go. You can find it in github or by typing git log or git reflog show at the command line and then do git reset --hard <SHA#>

Format a Go string without printing?

In your case, you need to use Sprintf() for format string.

func Sprintf(format string, a ...interface{}) string

Sprintf formats according to a format specifier and returns the resulting string.

s := fmt.Sprintf("Good Morning, This is %s and I'm living here from last %d years ", "John", 20)

Your output will be :

Good Morning, This is John and I'm living here from last 20 years.

Take screenshots in the iOS simulator

Press ?S or go to File > Save screenshot from your simulator menu and you will get the screenshot saved on your desktop.

How to put scroll bar only for modal-body?

What worked for me is setting the height to 100% the having the overflow on auto hope this will help

   <div style="height: 100%;overflow-y: auto;"> Some text o othre div scroll </div>

Find the version of an installed npm package

You can also check the version with this command:

npm info <package name> version

java.net.MalformedURLException: no protocol on URL based on a string modified with URLEncoder

This code worked for me

public static void main(String[] args) {
    try {
        java.net.URL myUr = new java.net.URL("http://path");
        System.out.println("Instantiated new URL: " + connection_url);
    }
    catch (MalformedURLException e) {
        e.printStackTrace();
    }
}

Instantiated new URL: http://path

How to sum array of numbers in Ruby?

Ruby 2.4.0 is released, and it has an Enumerable#sum method. So you can do

array.sum

Examples from the docs:

{ 1 => 10, 2 => 20 }.sum {|k, v| k * v }  #=> 50
(1..10).sum                               #=> 55
(1..10).sum {|v| v * 2 }                  #=> 110

Is <img> element block level or inline level?

behaves as an inline-block element as it allows other images in same line i.e. inline and also we can change the width and height of the image and this is the property of a block element. Hence, provide both the features of inline and block elements.

Difference between @Before, @BeforeClass, @BeforeEach and @BeforeAll

The basic difference between all these annotations is as follows -

  1. @BeforeEach - Use to run a common code before( eg setUp) each test method execution. analogous to JUnit 4’s @Before.
  2. @AfterEach - Use to run a common code after( eg tearDown) each test method execution. analogous to JUnit 4’s @After.
  3. @BeforeAll - Use to run once per class before any test execution. analogous to JUnit 4’s @BeforeClass.
  4. @AfterAll - Use to run once per class after all test are executed. analogous to JUnit 4’s @AfterClass.

All these annotations along with the usage is defined on Codingeek - Junit5 Test Lifecycle

How to make background of table cell transparent

What is this? :)

background-color: #D8F0DA;

Try

 background: none

And override works only if property is exactly the same.

background doesn't override background-color.

If you want alpha transparency, then use something like this

background: rgba(100, 100, 100, 0.5);

Underscore prefix for property and method names in JavaScript

import/export is now doing the job with ES6. I still tend to prefix not exported functions with _ if most of my functions are exported.

If you export only a class (like in angular projects), it's not needed at all.

export class MyOpenClass{

    open(){
         doStuff()
         this._privateStuff()
         return close();
    }

    _privateStuff() { /* _ only as a convention */} 

}

function close(){ /*... this is really private... */ }

Run php function on button click

No Problem You can use onClick() function easily without using any other interference of language,

<?php
echo '<br><Button onclick="document.getElementById(';?>'modal-wrapper2'<?php echo ').style.display=';?>'block'<?php echo '" name="comment" style="width:100px; color: white;background-color: black;border-radius: 10px; padding: 4px;">Show</button>';
?>

MySQL Select all columns from one table and some from another table

Using alias for referencing the tables to get the columns from different tables after joining them.

Select tb1.*, tb2.col1, tb2.col2 from table1 tb1 JOIN table2 tb2 on tb1.Id = tb2.Id

Text in Border CSS HTML

You can use a fieldset tag.

_x000D_
_x000D_
<!DOCTYPE html>_x000D_
<html>_x000D_
<body>_x000D_
_x000D_
<form>_x000D_
 <fieldset>_x000D_
  <legend>Personalia:</legend>_x000D_
  Name: <input type="text"><br>_x000D_
  Email: <input type="text"><br>_x000D_
  Date of birth: <input type="text">_x000D_
 </fieldset>_x000D_
</form>_x000D_
_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

Check this link: HTML Tag

Copy map values to vector in STL

You can't easily use a range here because the iterator you get from a map refers to a std::pair, where the iterators you would use to insert into a vector refers to an object of the type stored in the vector, which is (if you are discarding the key) not a pair.

I really don't think it gets much cleaner than the obvious:

#include <map>
#include <vector>
#include <string>
using namespace std;

int main() {
    typedef map <string, int> MapType;
    MapType m;  
    vector <int> v;

    // populate map somehow

    for( MapType::iterator it = m.begin(); it != m.end(); ++it ) {
        v.push_back( it->second );
    }
}

which I would probably re-write as a template function if I was going to use it more than once. Something like:

template <typename M, typename V> 
void MapToVec( const  M & m, V & v ) {
    for( typename M::const_iterator it = m.begin(); it != m.end(); ++it ) {
        v.push_back( it->second );
    }
}

batch file to check 64bit or 32bit OS

PROCESSOR_ARCHITECTURE=x86

Will appear on Win32, and

PROCESSOR_ARCHITECTURE=AMD64

will appear for Win64.

If you are perversely running the 32-bit cmd.exe process then Windows presents two environment variables:

PROCESSOR_ARCHITECTURE=x86
PROCESSOR_ARCHITEW6432=AMD64

Warning: comparison with string literals results in unspecified behaviour

I ran across this issue today working with a clients program. The program works FINE in VS6.0 using the following: (I've changed it slightly)

//
// This is the one include file that every user-written Nextest programs needs.
// Patcom-generated files will also look for this file.
//
#include "stdio.h"
#define IS_NONE( a_key )   ( ( a_key == "none" || a_key == "N/A" ) ? TRUE : FALSE )

//
// Note in my environment we have output() which is printf which adds /n at the end
//
main {
    char *psNameNone = "none";
    char *psNameNA   = "N/A";
    char *psNameCAT  = "CAT";

    if (IS_NONE(psNameNone) ) {
        output("psNameNone Matches NONE");
        output("%s psNameNoneAddr 0x%x  \"none\" addr 0x%X",
            psNameNone,psNameNone,
            "none");
    } else {
        output("psNameNone Does Not Match None");
        output("%s psNameNoneAddr 0x%x  \"none\" addr 0x%X",
            psNameNone,psNameNone,
            "none");
    }

    if (IS_NONE(psNameNA) ) {
        output("psNameNA Matches N/A");
        output("%s psNameNA 0x%x  \"N/A\" addr 0x%X",
        psNameNA,psNameNA,
        "N/A");
    } else {
        output("psNameNone Does Not Match N/A");
        output("%s psNameNA 0x%x  \"N/A\" addr 0x%X",
        psNameNA,psNameNA,
        "N/A");
    }
    if (IS_NONE(psNameCAT)) {
        output("psNameNA Matches CAT");
        output("%s psNameNA 0x%x  \"CAT\" addr 0x%X",
        psNameNone,psNameNone,
        "CAT");
    } else {
        output("psNameNA does not match CAT");
        output("%s psNameNA 0x%x  \"CAT\" addr 0x%X",
        psNameNone,psNameNone,
        "CAT");
    }
}

If built in VS6.0 with Program Database with Edit and Continue. The compares APPEAR to work. With this setting STRING pooling is enabled, and the compiler optimizes all STRING pointers to POINT TO THE SAME ADDRESSS, so this can work. Any strings created on the fly after compile time will have DIFFERENT addresses so will fail the compare. Where Compiler settings are Changing the setting to Program Database only will build the program so that it will fail.

How to change Visual Studio 2012,2013 or 2015 License Key?

For those of you using Visual Studio 2017 Professional, the registry key is:

HKCR\Licenses\5C505A59-E312-4B89-9508-E162F8150517

I also recommend you first export the registry key, before you delete it, so you'll have a backup if you accidentally delete the wrong key.

How to specify an element after which to wrap in css flexbox?

The only thing that appears to work is to set flex-wrap: wrap; on the container and them somehow make the child you want to break out after to fill the full width, so width: 100%; should work.

If, however, you can't stretch the element to 100% (for example, if it's an <img>), you can apply a margin to it, like width: 50px; margin-right: calc(100% - 50px).

"You may need an appropriate loader to handle this file type" with Webpack and Babel

This one throw me for a spin. Angular 7, Webpack I found this article so I want to give credit to the Article https://www.edc4it.com/blog/web/helloworld-angular2.html

What the solution is: //on your component file. use template as webpack will treat it as text template: require('./process.component.html')

for karma to interpret it npm install add html-loader --save-dev { test: /.html$/, use: "html-loader" },

Hope this helps somebody

How to deal with ModalDialog using selenium webdriver?

Try the below code. It is working in IE but not in FF22. If Modal dialog found is printed in Console, then Modal dialog is identified and switched.

 public class ModalDialog {

        public static void main(String[] args) throws InterruptedException {
            // TODO Auto-generated method stub
            WebDriver driver = new InternetExplorerDriver();
            //WebDriver driver = new FirefoxDriver();
            driver.get("http://samples.msdn.microsoft.com/workshop/samples/author/dhtml/refs/showModalDialog2.htm");
            String parent = driver.getWindowHandle();
            WebDriverWait wait = new WebDriverWait(driver, 10);
            WebElement push_to_create = wait.until(ExpectedConditions
                    .elementToBeClickable(By
                            .cssSelector("input[value='Push To Create']")));
            push_to_create.click();
            waitForWindow(driver);
            switchToModalDialog(driver, parent);

        }

        public static void waitForWindow(WebDriver driver)
                throws InterruptedException {
            //wait until number of window handles become 2 or until 6 seconds are completed.
            int timecount = 1;
            do {
                driver.getWindowHandles();
                Thread.sleep(200);
                timecount++;
                if (timecount > 30) {
                    break;
                }
            } while (driver.getWindowHandles().size() != 2);

        }

        public static void switchToModalDialog(WebDriver driver, String parent) { 
                //Switch to Modal dialog
            if (driver.getWindowHandles().size() == 2) {
                for (String window : driver.getWindowHandles()) {
                    if (!window.equals(parent)) {
                        driver.switchTo().window(window);
                        System.out.println("Modal dialog found");
                        break;
                    }
                }
            }
        }

    }

How to create a self-signed certificate for a domain name for development?

Another option is to create a self-signed certificate that allows you to specify the domain name per website. This means you can use it across many domain names.

In IIS Manager

  1. Click machine name node
  2. Open Server Certificates
  3. In Actions panel, choose 'Create Self-Signed Certificate'
  4. In 'Specify a friendly name...' name it *Dev (select 'Personal' from type list)
  5. Save

Now, on your website in IIS...

  1. Manage the bindings
  2. Create a new binding for Https
  3. Choose your self-signed certificate from the list
  4. Once selected, the domain name box will become enabled and you'll be able to input your domain name.

enter image description here

How do I get the RootViewController from a pushed controller?

Here I came up with universal method to navigate from any place to root.

  1. You create a new Class file with this class, so that it's accessible from anywhere in your project:

    import UIKit
    
    class SharedControllers
    {
        static func navigateToRoot(viewController: UIViewController)
        {
            var nc = viewController.navigationController
    
            // If this is a normal view with NavigationController, then we just pop to root.
            if nc != nil
            {
                nc?.popToRootViewControllerAnimated(true)
                return
            }
    
            // Most likely we are in Modal view, so we will need to search for a view with NavigationController.
            let vc = viewController.presentingViewController
    
            if nc == nil
            {
                nc = viewController.presentingViewController?.navigationController
            }
    
            if nc == nil
            {
                nc = viewController.parentViewController?.navigationController
            }
    
            if vc is UINavigationController && nc == nil
            {
                nc = vc as? UINavigationController
            }
    
            if nc != nil
            {
                viewController.dismissViewControllerAnimated(false, completion:
                    {
                        nc?.popToRootViewControllerAnimated(true)
                })
            }
        }
    }
    
  2. Usage from anywhere in your project:

    {
        ...
        SharedControllers.navigateToRoot(self)
        ...
    }
    

Formula to determine brightness of RGB color

The method could vary depending on your needs. Here are 3 ways to calculate Luminance:

  • Luminance (standard for certain colour spaces): (0.2126*R + 0.7152*G + 0.0722*B) source img

  • Luminance (perceived option 1): (0.299*R + 0.587*G + 0.114*B) source img

  • Luminance (perceived option 2, slower to calculate): sqrt( 0.241*R^2 + 0.691*G^2 + 0.068*B^2 ) ? sqrt( 0.299*R^2 + 0.587*G^2 + 0.114*B^2 ) (thanks to @MatthewHerbst) source img

[Edit: added examples using named css colors sorted with each method.]

jQuery's .on() method combined with the submit event

The problem here is that the "on" is applied to all elements that exists AT THE TIME. When you create an element dynamically, you need to run the on again:

$('form').on('submit',doFormStuff);

createNewForm();

// re-attach to all forms
$('form').off('submit').on('submit',doFormStuff);

Since forms usually have names or IDs, you can just attach to the new form as well. If I'm creating a lot of dynamic stuff, I'll include a setup or bind function:

function bindItems(){
    $('form').off('submit').on('submit',doFormStuff); 
    $('button').off('click').on('click',doButtonStuff);
}   

So then whenever you create something (buttons usually in my case), I just call bindItems to update everything on the page.

createNewButton();
bindItems();

I don't like using 'body' or document elements because with tabs and modals they tend to hang around and do things you don't expect. I always try to be as specific as possible unless its a simple 1 page project.

How to debug an apache virtual host configuration?

Here's a command I think could be of some help :

apachectl -t -D DUMP_VHOSTS

You'll get a list of all the vhosts, you'll know which one is the default one and you'll make sure that your syntax is correct (same as apachectl configtest suggested by yojimbo87).

You'll also know where each vhost is declared. It can be handy if your config files are a mess. ;)

Make selected block of text uppercase

Update on March 8, 2018 with Visual Studio Code 1.20.1 (mac)

It has been simplified quite a lot lately.
Very easy and straight forward now.

  1. From "Code" -> "Preferences" -> "Keyboard shortcuts"
  2. From the search box just search for "editor.action.transformTo", You will see the screen like: screenshot of keyboard shortcuts setup dialog in Visual Studio Code (mac)

  3. Click the "plus" sign at the left of each item, it will prompt dialog for your to [press] you desired key-bindings, after it showing that on the screen, just hit [Enter] to save.

exec failed because the name not a valid identifier?

As was in my case if your sql is generated by concatenating or uses converts then sql at execute need to be prefixed with letter N as below

e.g.

Exec N'Select bla..' 

the N defines string literal is unicode.

Stop form from submitting , Using Jquery

use this too :

if(e.preventDefault) 
   e.preventDefault(); 
else 
   e.returnValue = false;

Becoz e.preventDefault() is not supported in IE( some versions ). In IE it is e.returnValue = false

can you add HTTPS functionality to a python flask web server?

Deploy Flask on a real web server, rather than with the built-in (development) server.

See the Deployment Options chapter of the Flask documentation. Servers like Nginx and Apache both can handle setting up HTTPS servers rather than HTTP servers for your site.

The standalone WSGI servers listed would typically be deployed behind Nginx and Apache in a proxy-forwarding configuration, where the front-end server handles the SSL encryption for you still.

How to upload files in asp.net core?

You can add a new property of type IFormFile to your view model

public class CreatePost
{
   public string ImageCaption { set;get; }
   public string ImageDescription { set;get; }
   public IFormFile MyImage { set; get; }
}

and in your GET action method, we will create an object of this view model and send to the view.

public IActionResult Create()
{
   return View(new CreatePost());
}

Now in your Create view which is strongly typed to our view model, have a form tag which has the enctype attribute set to "multipart/form-data"

@model CreatePost
<form asp-action="Create" enctype="multipart/form-data">   

    <input asp-for="ImageCaption"/>
    <input asp-for="ImageDescription"/>
    <input asp-for="MyImage"/>

    <input type="submit"/>
</form>

And your HttpPost action to handle the form posting

[HttpPost]
public IActionResult Create(CreatePost model)
{
   var img = model.MyImage;
   var imgCaption = model.ImageCaption;

   //Getting file meta data
   var fileName = Path.GetFileName(model.MyImage.FileName);
   var contentType = model.MyImage.ContentType;

   // do something with the above data
   // to do : return something
}

If you want to upload the file to some directory in your app, you should use IHostingEnvironment to get the webroot path. Here is a working sample.

public class HomeController : Controller
{
    private readonly IHostingEnvironment hostingEnvironment;
    public HomeController(IHostingEnvironment environment)
    {
        hostingEnvironment = environment;
    }
    [HttpPost]
    public IActionResult Create(CreatePost model)
    {
        // do other validations on your model as needed
        if (model.MyImage != null)
        {
            var uniqueFileName = GetUniqueFileName(model.MyImage.FileName);
            var uploads = Path.Combine(hostingEnvironment.WebRootPath, "uploads");
            var filePath = Path.Combine(uploads,uniqueFileName);
            model.MyImage.CopyTo(new FileStream(filePath, FileMode.Create)); 

            //to do : Save uniqueFileName  to your db table   
        }
        // to do  : Return something
        return RedirectToAction("Index","Home");
    }
    private string GetUniqueFileName(string fileName)
    {
        fileName = Path.GetFileName(fileName);
        return  Path.GetFileNameWithoutExtension(fileName)
                  + "_" 
                  + Guid.NewGuid().ToString().Substring(0, 4) 
                  + Path.GetExtension(fileName);
    }
}

This will save the file to uploads folder inside wwwwroot directory of your app with a random file name generated using Guids ( to prevent overwriting of files with same name)

Here we are using a very simple GetUniqueName method which will add 4 chars from a guid to the end of the file name to make it somewhat unique. You can update the method to make it more sophisticated as needed.

Should you be storing the full url to the uploaded image in the database ?

No. Do not store the full url to the image in the database. What if tomorrow your business decides to change your company/product name from www.thefacebook.com to www.facebook.com ? Now you have to fix all the urls in the table!

What should you store ?

You should store the unique filename which you generated above(the uniqueFileName varibale we used above) to store the file name. When you want to display the image back, you can use this value (the filename) and build the url to the image.

For example, you can do this in your view.

@{
    var imgFileName = "cats_46df.png";
}
<img src="~/uploads/@imgFileName"  alt="my img"/>

I just hardcoded an image name to imgFileName variable and used that. But you may read the stored file name from your database and set to your view model property and use that. Something like

<img src="~/uploads/@Model.FileName"  alt="my img"/>

Storing the image to table

If you want to save the file as bytearray/varbinary to your database, you may convert the IFormFile object to byte array like this

private byte[] GetByteArrayFromImage(IFormFile file)
{
    using (var target = new MemoryStream())
    {
        file.CopyTo(target);
        return target.ToArray();
    }
}

Now in your http post action method, you can call this method to generate the byte array from IFormFile and use that to save to your table. the below example is trying to save a Post entity object using entity framework.

[HttpPost]
public IActionResult Create(CreatePost model)
{
    //Create an object of your entity class and map property values
    var post=new Post() { ImageCaption = model.ImageCaption };

    if (model.MyImage != null)
    {
       post.Image =  GetByteArrayFromImage(model.MyImage);
    }
    _context.Posts.Add(post);
    _context.SaveChanges();
    return RedirectToAction("Index","Home");
}

How to avoid a System.Runtime.InteropServices.COMException?

Your code (or some code called by you) is making a call to a COM method which is returning an unknown value. If you can find that then you're half way there.

You could try breaking when the exception is thrown. Go to Debug > Exceptions... and use the Find... option to locate System.Runtime.InteropServices.COMException. Tick the option to break when it's thrown and then debug your application.

Hopefully it will break somewhere meaningful and you'll be able to trace back and find the source of the error.

if (select count(column) from table) > 0 then

not so elegant but you dont need to declare any variable:

for k in (select max(1) from table where 1 = 1) loop
    update x where column = value;
end loop;

Why do I get permission denied when I try use "make" to install something?

Execute chmod 777 -R scripts/, it worked fine for me ;)

How to disable Python warnings?

I realise this is only applicable to a niche of the situations, but within a numpy context I really like using np.errstate:

np.sqrt(-1)
__main__:1: RuntimeWarning: invalid value encountered in sqrt
nan

However, using np.errstate:

with np.errstate(invalid='ignore'):
    np.sqrt(-1)
nan

The best part being you can apply this to very specific lines of code only.

The connection to adb is down, and a severe error has occurred

It's also possible to get this error if you are running the test project using JUnit instead of Android JUnit. Naturally, the solution is just to change how you run it.

How can I export a GridView.DataSource to a datatable or dataset?

Assuming your DataSource is of type DataTable, you can just do this:

myGridView.DataSource as DataTable

Floating point comparison functions for C#

Further to Andrew Wang's answer: if the BitConverter method is too slow but you cannot use unsafe code in your project, this struct is ~6x quicker than BitConverter:

[StructLayout(LayoutKind.Explicit)]
public struct FloatToIntSafeBitConverter
{
    public static int Convert(float value)
    {
        return new FloatToIntSafeBitConverter(value).IntValue;
    }

    public FloatToIntSafeBitConverter(float floatValue): this()
    {
        FloatValue = floatValue;
    }

    [FieldOffset(0)]
    public readonly int IntValue;

    [FieldOffset(0)]
    public readonly float FloatValue;
}

(Incidentally, I tried using the accepted solution but it (well my conversion at least) failed some of the unit tests also mentioned in the answer. e.g. assertTrue(nearlyEqual(Float.MIN_VALUE, -Float.MIN_VALUE)); )

What exactly is LLVM?

The LLVM Compiler Infrastructure is particularly useful for performing optimizations and transformations on code. It also consists of a number of tools serving distinct usages. llvm-prof is a profiling tool that allows you to do profiling of execution in order to identify program hotspots. Opt is an optimization tool that offers various optimization passes (dead code elimination for instance).

Importantly LLVM provides you with the libraries, to write your own Passes. For instance if you require to add a range check on certain arguments that are passed into certain functions of a Program, writing a simple LLVM Pass would suffice.

For more information on writing your own Pass, check this http://llvm.org/docs/WritingAnLLVMPass.html

Adding dictionaries together, Python

If you're interested in creating a new dict without using intermediary storage: (this is faster, and in my opinion, cleaner than using dict.items())

dic2 = dict(dic0, **dic1)

Or if you're happy to use one of the existing dicts:

dic0.update(dic1)

Where can I download Spring Framework jars without using Maven?

Please edit to keep this list of mirrors current

I found this maven repo where you could download from directly a zip file containing all the jars you need.

Alternate solution: Maven

The solution I prefer is using Maven, it is easy and you don't have to download each jar alone. You can do it with the following steps:

  1. Create an empty folder anywhere with any name you prefer, for example spring-source

  2. Create a new file named pom.xml

  3. Copy the xml below into this file

  4. Open the spring-source folder in your console

  5. Run mvn install

  6. After download finished, you'll find spring jars in /spring-source/target/dependencies

    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>spring-source-download</groupId>
      <artifactId>SpringDependencies</artifactId>
      <version>1.0</version>
      <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      </properties>
      <dependencies>
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
          <version>3.2.4.RELEASE</version>
        </dependency>
      </dependencies>
      <build>
        <plugins>
          <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <version>2.8</version>
            <executions>
              <execution>
                <id>download-dependencies</id>
                <phase>generate-resources</phase>
                <goals>
                  <goal>copy-dependencies</goal>
                </goals>
                <configuration>
                  <outputDirectory>${project.build.directory}/dependencies</outputDirectory>
                </configuration>
              </execution>
            </executions>
          </plugin>
        </plugins>
      </build>
    </project>
    

Also, if you need to download any other spring project, just copy the dependency configuration from its corresponding web page.

For example, if you want to download Spring Web Flow jars, go to its web page, and add its dependency configuration to the pom.xml dependencies, then run mvn install again.

<dependency>
  <groupId>org.springframework.webflow</groupId>
  <artifactId>spring-webflow</artifactId>
  <version>2.3.2.RELEASE</version>
</dependency>

numpy get index where value is true

To get the row numbers where at least one item is larger than 15:

>>> np.where(np.any(e>15, axis=1))
(array([1, 2], dtype=int64),)

Printing an array in C++?

Use the STL

#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>

int main()
{
    std::vector<int>    userInput;

    // Read until end of input.
    // Hit control D  
    std::copy(std::istream_iterator<int>(std::cin),
              std::istream_iterator<int>(),
              std::back_inserter(userInput)
             );

    // Print in Normal order
    std::copy(userInput.begin(),
              userInput.end(),
              std::ostream_iterator<int>(std::cout,",")
             );
    std::cout << "\n";

    // Print in reverse order:
    std::copy(userInput.rbegin(),
              userInput.rend(),
              std::ostream_iterator<int>(std::cout,",")
             );
    std::cout << "\n";

    // Update for C++11
    // Range based for is now a good alternative.
    for(auto const& value: userInput)
    {
        std::cout << value << ",";
    }
    std::cout << "\n";
}

How do I run a program from command prompt as a different user and as an admin

You can use psexec.exe from Microsoft Sysinternals Suite https://docs.microsoft.com/en-us/sysinternals/downloads/sysinternals-suite

Example:

c:\somedir\psexec.exe -u domain\user -p password cmd.exe

List files committed for a revision

From remote repo:

svn log -v -r 42 --stop-on-copy --non-interactive --no-auth-cache --username USERNAME --password PASSWORD http://repourl/projectname/

How can I mock an ES6 module import using Jest?

I've been able to solve this by using a hack involving import *. It even works for both named and default exports!

For a named export:

// dependency.js
export const doSomething = (y) => console.log(y)

// myModule.js
import { doSomething } from './dependency';

export default (x) => {
  doSomething(x * 2);
}

// myModule-test.js
import myModule from '../myModule';
import * as dependency from '../dependency';

describe('myModule', () => {
  it('calls the dependency with double the input', () => {
    dependency.doSomething = jest.fn(); // Mutate the named export

    myModule(2);

    expect(dependency.doSomething).toBeCalledWith(4);
  });
});

Or for a default export:

// dependency.js
export default (y) => console.log(y)

// myModule.js
import dependency from './dependency'; // Note lack of curlies

export default (x) => {
  dependency(x * 2);
}

// myModule-test.js
import myModule from '../myModule';
import * as dependency from '../dependency';

describe('myModule', () => {
  it('calls the dependency with double the input', () => {
    dependency.default = jest.fn(); // Mutate the default export

    myModule(2);

    expect(dependency.default).toBeCalledWith(4); // Assert against the default
  });
});

As Mihai Damian quite rightly pointed out below, this is mutating the module object of dependency, and so it will 'leak' across to other tests. So if you use this approach you should store the original value and then set it back again after each test.

To do this easily with Jest, use the spyOn() method instead of jest.fn(), because it supports easily restoring its original value, therefore avoiding before mentioned 'leaking'.

how to open a page in new tab on button click in asp.net?

Add_ supplier is name of the form

private void add_supplier_Load(object sender, EventArgs e)
{
    add_supplier childform = new add_supplier();
    childform.MdiParent = this;
    childform.Show();
}

Is it possible to declare a variable in Gradle usable in Java?

How can you insert String result of function into buildConfigField

Here's an example of build date in human-readable format set:

def getDate() {
    return new SimpleDateFormat("dd MMMM yyyy", new Locale("ru")).format(new Date())
}

def buildDate = getDate()

defaultConfig {
    buildConfigField "String", "BUILD_DATE", "\"$buildDate\""
}

What is the difference between __dirname and ./ in node.js?

./ refers to the current working directory, except in the require() function. When using require(), it translates ./ to the directory of the current file called. __dirname is always the directory of the current file.

For example, with the following file structure

/home/user/dir/files/config.json

{
  "hello": "world"
}

/home/user/dir/files/somefile.txt

text file

/home/user/dir/dir.js

var fs = require('fs');

console.log(require('./files/config.json'));
console.log(fs.readFileSync('./files/somefile.txt', 'utf8'));

If I cd into /home/user/dir and run node dir.js I will get

{ hello: 'world' }
text file

But when I run the same script from /home/user/ I get

{ hello: 'world' }

Error: ENOENT, no such file or directory './files/somefile.txt'
    at Object.openSync (fs.js:228:18)
    at Object.readFileSync (fs.js:119:15)
    at Object.<anonymous> (/home/user/dir/dir.js:4:16)
    at Module._compile (module.js:432:26)
    at Object..js (module.js:450:10)
    at Module.load (module.js:351:31)
    at Function._load (module.js:310:12)
    at Array.0 (module.js:470:10)
    at EventEmitter._tickCallback (node.js:192:40)

Using ./ worked with require but not for fs.readFileSync. That's because for fs.readFileSync, ./ translates into the cwd (in this case /home/user/). And /home/user/files/somefile.txt does not exist.

How to convert this var string to URL in Swift

In swift 3 use:

let url = URL(string: "Whatever url you have(eg: https://google.com)")

Long Press in JavaScript?

For cross platform developers (Note All answers given so far will not work on iOS):

Mouseup/down seemed to work okay on android - but not all devices ie (samsung tab4). Did not work at all on iOS.

Further research its seems that this is due to the element having selection and the native magnification interupts the listener.

This event listener enables a thumbnail image to be opened in a bootstrap modal, if the user holds the image for 500ms.

It uses a responsive image class therefore showing a larger version of the image. This piece of code has been fully tested upon (iPad/Tab4/TabA/Galaxy4):

var pressTimer;  
$(".thumbnail").on('touchend', function (e) {
   clearTimeout(pressTimer);
}).on('touchstart', function (e) {
   var target = $(e.currentTarget);
   var imagePath = target.find('img').attr('src');
   var title = target.find('.myCaption:visible').first().text();
   $('#dds-modal-title').text(title);
   $('#dds-modal-img').attr('src', imagePath);
   // Set timeout
   pressTimer = window.setTimeout(function () {
      $('#dds-modal').modal('show');
   }, 500)
});

What's the best way to detect a 'touch screen' device using JavaScript?

var isTouchScreen = 'createTouch' in document;

or

var isTouchScreen = 'createTouch' in document || screen.width <= 699 || 
    ua.match(/(iPhone|iPod|iPad)/) || ua.match(/BlackBerry/) || 
    ua.match(/Android/);

would be a more thorough check I suppose.

Full Page <iframe>

This is cross-browser and fully responsive:

<iframe
  src="https://drive.google.com/file/d/0BxrMaW3xINrsR3h2cWx0OUlwRms/preview"
  style="
    position: fixed;
    top: 0px;
    bottom: 0px;
    right: 0px;
    width: 100%;
    border: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    z-index: 999999;
    height: 100%;
  ">
</iframe>

Unit testing with Spring Security

Personally I would just use Powermock along with Mockito or Easymock to mock the static SecurityContextHolder.getSecurityContext() in your unit/integration test e.g.

@RunWith(PowerMockRunner.class)
@PrepareForTest(SecurityContextHolder.class)
public class YourTestCase {

    @Mock SecurityContext mockSecurityContext;

    @Test
    public void testMethodThatCallsStaticMethod() {
        // Set mock behaviour/expectations on the mockSecurityContext
        when(mockSecurityContext.getAuthentication()).thenReturn(...)
        ...
        // Tell mockito to use Powermock to mock the SecurityContextHolder
        PowerMockito.mockStatic(SecurityContextHolder.class);

        // use Mockito to set up your expectation on SecurityContextHolder.getSecurityContext()
        Mockito.when(SecurityContextHolder.getSecurityContext()).thenReturn(mockSecurityContext);
        ...
    }
}

Admittedly there is quite a bit of boiler plate code here i.e. mock an Authentication object, mock a SecurityContext to return the Authentication and finally mock the SecurityContextHolder to get the SecurityContext, however its very flexible and allows you to unit test for scenarios like null Authentication objects etc. without having to change your (non test) code

Php - testing if a radio button is selected and get the value

I suggest you do it through the GET request: for example, index.html:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<form action="result.php" method="post">
  Answer 1 <input type="radio" name="ans" value="ans1" /><br />
  Answer 2 <input type="radio" name="ans" value="ans2"  /><br />
  Answer 3 <input type="radio" name="ans" value="ans3"  /><br />
  Answer 4 <input type="radio" name="ans" value="ans4"  /><br />
  <input type="button" value="submit" onclick="sendPost()" />
 </form>
 <script type="text/javascript">
    function sendPost(){
        var value = $('input[name="ans"]:checked').val();
        window.location.href = "sendpost.php?ans="+value;
    };
 </script>

this is sendpost.php:

<?php
if(isset($_GET["ans"]) AND !empty($_GET["ans"])){
    echo $_GET["ans"];
}
?>

best way to preserve numpy arrays on disk

I've compared performance (space and time) for a number of ways to store numpy arrays. Few of them support multiple arrays per file, but perhaps it's useful anyway.

benchmark for numpy array storage

Npy and binary files are both really fast and small for dense data. If the data is sparse or very structured, you might want to use npz with compression, which'll save a lot of space but cost some load time.

If portability is an issue, binary is better than npy. If human readability is important, then you'll have to sacrifice a lot of performance, but it can be achieved fairly well using csv (which is also very portable of course).

More details and the code are available at the github repo.

How to vertically align <li> elements in <ul>?

I had the same problem. Try this.

<nav>
    <ul>
        <li><a href="#">AnaSayfa</a></li>
        <li><a href="#">Hakkimizda</a></li>
        <li><a href="#">Iletisim</a></li>
    </ul>
</nav>
@charset "utf-8";

nav {
    background-color: #9900CC;
    height: 80px;
    width: 400px;
}

ul {
    list-style: none;
    float: right;
    margin: 0;
}

li {
    float: left;
    width: 100px;
    line-height: 80px;
    vertical-align: middle;
    text-align: center;
    margin: 0;
}

nav li a {
    width: 100px;
    text-decoration: none;
    color: #FFFFFF;
}

Build a simple HTTP server in C

Mongoose (Formerly Simple HTTP Daemon) is pretty good. In particular, it's embeddable and compiles under Windows, Windows CE, and UNIX.

Divide a number by 3 without using *, /, +, -, % operators

Generally, a solution to this would be:

log(pow(exp(numerator),pow(denominator,-1)))

Guzzlehttp - How get the body of a response from Guzzle 6?

If expecting JSON back, the simplest way to get it:

$data = json_decode($response->getBody()); // returns an object

// OR

$data = json_decode($response->getBody(), true); // returns an array

json_decode() will automatically cast the body to string, so there is no need to call getContents().

Regex to Match Symbols: !$%^&*()_+|~-=`{}[]:";'<>?,./

The most simple and shortest way to accomplish this:

/[^\p{L}\d\s@#]/u

Explanation

[^...] Match a single character not present in the list below

  • \p{L} => matches any kind of letter from any language

  • \d => matches a digit zero through nine

  • \s => matches any kind of invisible character

  • @# => @ and # characters

Don't forget to pass the u (unicode) flag.

Best way to do a PHP switch with multiple values per case?

Switch in combination with variable variables will give you more flexibility:

<?php
$p = 'home'; //For testing

$p = ( strpos($p, 'users') !== false? 'users': $p);
switch ($p) { 
    default:
        $varContainer = 'current_' . $p; //Stores the variable [$current_"xyORz"] into $varContainer
        ${$varContainer} = 'current'; //Sets the VALUE of [$current_"xyORz"] to 'current'
    break;

}
//For testing
echo $current_home;
?>

To learn more, checkout variable variables and the examples I submitted to php manual:
Example 1: http://www.php.net/manual/en/language.variables.variable.php#105293
Example 2: http://www.php.net/manual/en/language.variables.variable.php#105282

PS: This example code is SMALL AND SIMPLE, just the way I like it. It's tested and works too

Is it possible to use a batch file to establish a telnet session, send a command and have the output written to a file?

The microsoft telnet.exe is not scriptable without using another script (which needs keyboard focus), as shown in another answer to this question, but there is a free

Telnet Scripting Tool v.1.0 by Albert Yale

that you can google for and which is both scriptable and loggable and can be launched from a batch file without needing keyboard focus.

The problem with telnet.exe and a second script when keyboard focus is being used is that if someone is using the computer at the time the script runs, then it is highly likely that the script will fail due to mouse clicks and keyboard use at that moment in time.

What is the difference between UTF-8 and Unicode?

They're not the same thing - UTF-8 is a particular way of encoding Unicode.

There are lots of different encodings you can choose from depending on your application and the data you intend to use. The most common are UTF-8, UTF-16 and UTF-32 s far as I know.

How to check if an environment variable exists and get its value?

There is no difference between environment variables and variables in a script. Environment variables are just defined earlier, outside the script, before the script is called. From the script's point of view, a variable is a variable.

You can check if a variable is defined:

if [ -z "$a" ]
then
    echo "not defined"
else 
    echo "defined"
fi

and then set a default value for undefined variables or do something else.

The -z checks for a zero-length (i.e. empty) string. See man bash and look for the CONDITIONAL EXPRESSIONS section.

You can also use set -u at the beginning of your script to make it fail once it encounters an undefined variable, if you want to avoid having an undefined variable breaking things in creative ways.

Replace whitespaces with tabs in linux

Download and run the following script to recursively convert soft tabs to hard tabs in plain text files.

Place and execute the script from inside the folder which contains the plain text files.

#!/bin/bash

find . -type f -and -not -path './.git/*' -exec grep -Iq . {} \; -and -print | while read -r file; do {
    echo "Converting... "$file"";
    data=$(unexpand --first-only -t 4 "$file");
    rm "$file";
    echo "$data" > "$file";
}; done;

Java math function to convert positive int to negative and negative to positive?

Just use the unary minus operator:

int x = 5;
...
x = -x; // Here's the mystery library function - the single character "-"

Java has two minus operators:

  • the familiar arithmetic version (eg 0 - x), and
  • the unary minus operation (used here), which negates the (single) operand

This compiles and works as expected.

How to run Rake tasks from within Rake tasks?

I would suggest not to create general debug and release tasks if the project is really something that gets compiled and so results in files. You should go with file-tasks which is quite doable in your example, as you state, that your output goes into different directories. Say your project just compiles a test.c file to out/debug/test.out and out/release/test.out with gcc you could setup your project like this:

WAYS = ['debug', 'release']
FLAGS = {}
FLAGS['debug'] = '-g'
FLAGS['release'] = '-O'
def out_dir(way)
  File.join('out', way)
end
def out_file(way)
  File.join(out_dir(way), 'test.out')
end
WAYS.each do |way|
  desc "create output directory for #{way}"
  directory out_dir(way)

  desc "build in the #{way}-way"
  file out_file(way) => [out_dir(way), 'test.c'] do |t|
    sh "gcc #{FLAGS[way]} -c test.c -o #{t.name}"
  end
end
desc 'build all ways'
task :all => WAYS.map{|way|out_file(way)}

task :default => [:all]

This setup can be used like:

rake all # (builds debug and release)
rake debug # (builds only debug)
rake release # (builds only release)

This does a little more as asked for, but shows my points:

  1. output directories are created, as necessary.
  2. the files are only recompiled if needed (this example is only correct for the simplest of test.c files).
  3. you have all tasks readily at hand if you want to trigger the release build or the debug build.
  4. this example includes a way to also define small differences between debug and release-builds.
  5. no need to reenable a build-task that is parametrized with a global variable, because now the different builds have different tasks. the codereuse of the build-task is done by reusing the code to define the build-tasks. see how the loop does not execute the same task twice, but instead created tasks, that can later be triggered (either by the all-task or be choosing one of them on the rake commandline).

php $_POST array empty upon form submission

I could solve the problem using enctype="application/x-www-form-urlencoded" as the default is "text/plain". When you check in $DATA the seperator is a space for "text/plain" and a special character for the "urlencoded".

Kind regards Frank

Hash string in c#

The fastest way, to get a hash string for password store purposes, is a following code:

    internal static string GetStringSha256Hash(string text)
    {
        if (String.IsNullOrEmpty(text))
            return String.Empty;

        using (var sha = new System.Security.Cryptography.SHA256Managed())
        {
            byte[] textData = System.Text.Encoding.UTF8.GetBytes(text);
            byte[] hash = sha.ComputeHash(textData);
            return BitConverter.ToString(hash).Replace("-", String.Empty);
        }
    }

Remarks:

  • if the method is invoked often, the creation of sha variable should be refactored into a class field;
  • output is presented as encoded hex string;

ASP.Net Download file to client browser

Try changing it to.

 Response.Clear();
 Response.ClearHeaders();
 Response.ClearContent();
 Response.AddHeader("Content-Disposition", "attachment; filename=" + file.Name);
 Response.AddHeader("Content-Length", file.Length.ToString());
 Response.ContentType = "text/plain";
 Response.Flush();
 Response.TransmitFile(file.FullName);
 Response.End();

Read whole ASCII file into C++ std::string

Update: Turns out that this method, while following STL idioms well, is actually surprisingly inefficient! Don't do this with large files. (See: http://insanecoding.blogspot.com/2011/11/how-to-read-in-file-in-c.html)

You can make a streambuf iterator out of the file and initialize the string with it:

#include <string>
#include <fstream>
#include <streambuf>

std::ifstream t("file.txt");
std::string str((std::istreambuf_iterator<char>(t)),
                 std::istreambuf_iterator<char>());

Not sure where you're getting the t.open("file.txt", "r") syntax from. As far as I know that's not a method that std::ifstream has. It looks like you've confused it with C's fopen.

Edit: Also note the extra parentheses around the first argument to the string constructor. These are essential. They prevent the problem known as the "most vexing parse", which in this case won't actually give you a compile error like it usually does, but will give you interesting (read: wrong) results.

Following KeithB's point in the comments, here's a way to do it that allocates all the memory up front (rather than relying on the string class's automatic reallocation):

#include <string>
#include <fstream>
#include <streambuf>

std::ifstream t("file.txt");
std::string str;

t.seekg(0, std::ios::end);   
str.reserve(t.tellg());
t.seekg(0, std::ios::beg);

str.assign((std::istreambuf_iterator<char>(t)),
            std::istreambuf_iterator<char>());

Explanation of 'String args[]' and static in 'public static void main(String[] args)'

I just thought I'd chip in on this one. It's been answered perfectly well by others though.

The full main method declaration should be :

 public static void main(final String[] args) throws Exception {

 }

The args are declared final because technically they should not be altered. They are console parameters given by the user.

You should usually specify that main throws Exception so that stack traces can be echoed to console easily without needing to do e.printStackTrace() etc.

As for Array Syntax. I prefer it this way. I suppose that it's a little bit like the difference between french and english. In English it's "a black car", in french it's "a car black". Which is the important noun, car, or black?

I don't like this sort of thing :

String blah[] = {};

What's important here is that it's a String array, so it should be

String[] blah = {};

blah is just a name. I personally think it's a bit of a mistake in Java that arrays can sometimes be declared in that manner.

What are MVP and MVC and what is the difference?

There are many answers to the question, but I felt there is a need for some really simple answer clearly comparing the two. Here's the discussion I made up when a user searches for a movie name in an MVP and MVC app:

User: Click click …

View: Who’s that? [MVP|MVC]

User: I just clicked on the search button …

View: Ok, hold on a sec … . [MVP|MVC]

( View calling the Presenter|Controller … ) [MVP|MVC]

View: Hey Presenter|Controller, a User has just clicked on the search button, what shall I do? [MVP|MVC]

Presenter|Controller: Hey View, is there any search term on that page? [MVP|MVC]

View: Yes,… here it is … “piano” [MVP|MVC]

Presenter: Thanks View,… meanwhile I’m looking up the search term on the Model, please show him/her a progress bar [MVP|MVC]

( Presenter|Controller is calling the Model … ) [MVP|MVC]

Presenter|Controller: Hey Model, Do you have any match for this search term?: “piano” [MVP|MVC]

Model: Hey Presenter|Controller, let me check … [MVP|MVC]

( Model is making a query to the movie database … ) [MVP|MVC]

( After a while ... )

-------------- This is where MVP and MVC start to diverge ---------------

Model: I found a list for you, Presenter, here it is in JSON “[{"name":"Piano Teacher","year":2001},{"name":"Piano","year":1993}]” [MVP]

Model: There is some result available, Controller. I have created a field variable in my instance and filled it with the result. It's name is "searchResultsList" [MVC]

(Presenter|Controller thanks Model and gets back to the View) [MVP|MVC]

Presenter: Thanks for waiting View, I found a list of matching results for you and arranged them in a presentable format: ["Piano Teacher 2001","Piano 1993"]. Please show it to the user in a vertical list. Also please hide the progress bar now [MVP]

Controller: Thanks for waiting View, I have asked Model about your search query. It says it has found a list of matching results and stored them in a variable named "searchResultsList" inside its instance. You can get it from there. Also please hide the progress bar now [MVC]

View: Thank you very much Presenter [MVP]

View: Thank you "Controller" [MVC] (Now the View is questioning itself: How should I present the results I get from the Model to the user? Should the production year of the movie come first or last...? Should it be in a vertical or horizontal list? ...)

In case you're interested, I have been writing a series of articles dealing with app architectural patterns (MVC, MVP, MVVP, clean architecture, ...) accompanied by a Github repo here. Even though the sample is written for android, the underlying principles can be applied to any medium.

JAVA_HOME should point to a JDK not a JRE

Be sure to use the correct path!

I mistakenly had written C:\Program Files\Java\. Changing it to C:\Program Files\Java\jdk\11.0.6\ fixed the issue.

In cmd I then checked for the version of maven with mvn -version.

Reading an image file in C/C++

corona is nice. From the tutorial:

corona::Image* image = corona::OpenImage("img.jpg", corona::PF_R8G8B8A8);
if (!image) {
  // error!
}

int width  = image->getWidth();
int height = image->getHeight();
void* pixels = image->getPixels();

// we're guaranteed that the first eight bits of every pixel is red,
// the next eight bits is green, and so on...
typedef unsigned char byte;
byte* p = (byte*)pixels;
for (int i = 0; i < width * height; ++i) {
  byte red   = *p++;
  byte green = *p++;
  byte blue  = *p++;
  byte alpha = *p++;
}

pixels would be a one dimensional array, but you could easily convert a given x and y position to a position in a 1D array. Something like pos = (y * width) + x

In C - check if a char exists in a char array

I believe the original question said:

a character belongs to a list/array of invalid characters

and not:

belongs to a null-terminated string

which, if it did, then strchr would indeed be the most suitable answer. If, however, there is no null termination to an array of chars or if the chars are in a list structure, then you will need to either create a null-terminated string and use strchr or manually iterate over the elements in the collection, checking each in turn. If the collection is small, then a linear search will be fine. A large collection may need a more suitable structure to improve the search times - a sorted array or a balanced binary tree for example.

Pick whatever works best for you situation.

Does `anaconda` create a separate PYTHONPATH variable for each new environment?

Anaconda does not use the PYTHONPATH. One should however note that if the PYTHONPATH is set it could be used to load a library that is not in the anaconda environment. That is why before activating an environment it might be good to do a

unset PYTHONPATH

For instance this PYTHONPATH points to an incorrect pandas lib:

export PYTHONPATH=/home/john/share/usr/anaconda/lib/python
source activate anaconda-2.7
python
>>>> import pandas as pd
/home/john/share/usr/lib/python/pandas-0.12.0-py2.7-linux-x86_64.egg/pandas/hashtable.so: undefined symbol: PyUnicodeUCS2_DecodeUTF8
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/john/share/usr/lib/python/pandas-0.12.0-py2.7-linux-x86_64.egg/pandas/__init__.py", line 6, in <module>
    from . import hashtable, tslib, lib
ImportError: /home/john/share/usr/lib/python/pandas-0.12.0-py2.7-linux-x86_64.egg/pandas/hashtable.so: undefined symbol: PyUnicodeUCS2_DecodeUTF8

unsetting the PYTHONPATH prevents the wrong pandas lib from being loaded:

unset PYTHONPATH
source activate anaconda-2.7
python
>>>> import pandas as pd
>>>>

What causes javac to issue the "uses unchecked or unsafe operations" warning

This warning also could be raised due to

new HashMap() or new ArrayList() that is generic type has to be specific otherwise the compiler will generate warning.

Please make sure that if you code contains the following you have to change accordingly

new HashMap() => Map map = new HashMap() new HashMap() => Map map = new HashMap<>()

new ArrayList() => List map = new ArrayList() new ArrayList() => List map = new ArrayList<>()

Php $_POST method to get textarea value

Try to use different id and name parameters, currently you have same here. Please visit the link below for the same, this might be help you :

Issue using $_POST with a textarea

How to copy file from one location to another location?

  public static void copyFile(File oldLocation, File newLocation) throws IOException {
        if ( oldLocation.exists( )) {
            BufferedInputStream  reader = new BufferedInputStream( new FileInputStream(oldLocation) );
            BufferedOutputStream  writer = new BufferedOutputStream( new FileOutputStream(newLocation, false));
            try {
                byte[]  buff = new byte[8192];
                int numChars;
                while ( (numChars = reader.read(  buff, 0, buff.length ) ) != -1) {
                    writer.write( buff, 0, numChars );
                }
            } catch( IOException ex ) {
                throw new IOException("IOException when transferring " + oldLocation.getPath() + " to " + newLocation.getPath());
            } finally {
                try {
                    if ( reader != null ){                      
                        writer.close();
                        reader.close();
                    }
                } catch( IOException ex ){
                    Log.e(TAG, "Error closing files when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() ); 
                }
            }
        } else {
            throw new IOException("Old location does not exist when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() );
        }
    }  

What's the difference between @JoinColumn and mappedBy when using a JPA @OneToMany association

Unidirectional one-to-many association

If you use the @OneToMany annotation with @JoinColumn, then you have a unidirectional association, like the one between the parent Post entity and the child PostComment in the following diagram:

Unidirectional one-to-many association

When using a unidirectional one-to-many association, only the parent side maps the association.

In this example, only the Post entity will define a @OneToMany association to the child PostComment entity:

@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
@JoinColumn(name = "post_id")
private List<PostComment> comments = new ArrayList<>();

Bidirectional one-to-many association

If you use the @OneToMany with the mappedBy attribute set, you have a bidirectional association. In our case, both the Post entity has a collection of PostComment child entities, and the child PostComment entity has a reference back to the parent Post entity, as illustrated by the following diagram:

Bidirectional one-to-many association

In the PostComment entity, the post entity property is mapped as follows:

@ManyToOne(fetch = FetchType.LAZY)
private Post post;

The reason we explicitly set the fetch attribute to FetchType.LAZY is because, by default, all @ManyToOne and @OneToOne associations are fetched eagerly, which can cause N+1 query issues.

In the Post entity, the comments association is mapped as follows:

@OneToMany(
    mappedBy = "post",
    cascade = CascadeType.ALL,
    orphanRemoval = true
)
private List<PostComment> comments = new ArrayList<>();

The mappedBy attribute of the @OneToMany annotation references the post property in the child PostComment entity, and, this way, Hibernate knows that the bidirectional association is controlled by the @ManyToOne side, which is in charge of managing the Foreign Key column value this table relationship is based on.

For a bidirectional association, you also need to have two utility methods, like addChild and removeChild:

public void addComment(PostComment comment) {
    comments.add(comment);
    comment.setPost(this);
}

public void removeComment(PostComment comment) {
    comments.remove(comment);
    comment.setPost(null);
}

These two methods ensure that both sides of the bidirectional association are in sync. Without synchronizing both ends, Hibernate does not guarantee that association state changes will propagate to the database.

Which one to choose?

The unidirectional @OneToMany association does not perform very well, so you should avoid it.

You are better off using the bidirectional @OneToMany which is more efficient.

How to fix the Hibernate "object references an unsaved transient instance - save the transient instance before flushing" error

My problem was related to @BeforeEach of JUnit. And even if I saved the related entities (in my case @ManyToOne), I got the same error.

The problem is somehow related to the sequence that I have in my parent. If I assign the value to that attribute, the problem is solved.

Ex. If I have the entity Question that can have some categories (one or more) and entity Question has a sequence:

@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "feedbackSeq")
@Id
private Long id;

I have to assign the value question.setId(1L);

The object 'DF__*' is dependent on column '*' - Changing int to double

As constraint has unpredictable name, you can write special script(DropConstraint) to remove it without knowing it's name (was tested at EF 6.1.3):

public override void Up()
{    
    DropConstraint();
    AlterColumn("dbo.MyTable", "Rating", c => c.Double(nullable: false));
}

private void DropConstraint()
{
    Sql(@"DECLARE @var0 nvarchar(128)
          SELECT @var0 = name
          FROM sys.default_constraints
          WHERE parent_object_id = object_id(N'dbo.MyTable')
          AND col_name(parent_object_id, parent_column_id) = 'Rating';
          IF @var0 IS NOT NULL
              EXECUTE('ALTER TABLE [dbo].[MyTable] DROP CONSTRAINT [' + @var0 + ']')");
}

public override void Down()
{            
    AlterColumn("dbo.MyTable", "Rating", c => c.Int(nullable: false));    
}

onActivityResult is not being called in Fragment

FOR MANY NESTED FRAGMENTS (for example, when using a ViewPager in a fragment)

In your main activity:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
}

In your fragment:

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    for (Fragment fragment : getChildFragmentManager().getFragments()) {
        fragment.onActivityResult(requestCode, resultCode, data);
    }
}

In your nested fragment

Call activity

getParentFragment().startActivityForResult(intent, uniqueInstanceInt);

uniqueInstanceInt - replace it with an int that is unique among the nested fragments to prevent another fragment treat the answer.

Receive response

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == uniqueInstanceInt ) {
        // TODO your code
    }
}

Attention

A number between 0 and 65536 need be used in uniqueInstanceInt for error avoid "Can only use lower 16 bits for requestCode".

Any way to make a WPF textblock selectable?

There is an alternative solution that might be adaptable to the RichTextBox oultined in this blog post - it used a trigger to swap out the control template when the use hovers over the control - should help with performance

Reactive forms - disabled attribute

I tried these in angular 7. It worked successfully.

this.form.controls['fromField'].reset();
if(condition){
      this.form.controls['fromField'].enable();
}
else{
      this.form.controls['fromField'].disable();
}

The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception

The general issue is just any issue involving Machine/Web/App configs.

I had the same connection strings in Machine.Config as in my App.Config so I put before my first connection string in my App.Config

Chaining Observables in RxJS

About promise composition vs. Rxjs, as this is a frequently asked question, you can refer to a number of previously asked questions on SO, among which :

Basically, flatMap is the equivalent of Promise.then.

For your second question, do you want to replay values already emitted, or do you want to process new values as they arrive? In the first case, check the publishReplay operator. In the second case, standard subscription is enough. However you might need to be aware of the cold. vs. hot dichotomy depending on your source (cf. Hot and Cold observables : are there 'hot' and 'cold' operators? for an illustrated explanation of the concept)

Find the maximum value in a list of tuples in Python

Use max():

 
Using itemgetter():

In [53]: lis=[(101, 153), (255, 827), (361, 961)]

In [81]: from operator import itemgetter

In [82]: max(lis,key=itemgetter(1))[0]    #faster solution
Out[82]: 361

using lambda:

In [54]: max(lis,key=lambda item:item[1])
Out[54]: (361, 961)

In [55]: max(lis,key=lambda item:item[1])[0]
Out[55]: 361

timeit comparison:

In [30]: %timeit max(lis,key=itemgetter(1))
1000 loops, best of 3: 232 us per loop

In [31]: %timeit max(lis,key=lambda item:item[1])
1000 loops, best of 3: 556 us per loop

On design patterns: When should I use the singleton?

A singleton should be used when managing access to a resource which is shared by the entire application, and it would be destructive to potentially have multiple instances of the same class. Making sure that access to shared resources thread safe is one very good example of where this kind of pattern can be vital.

When using Singletons, you should make sure that you're not accidentally concealing dependencies. Ideally, the singletons (like most static variables in an application) be set up during the execution of your initialization code for the application (static void Main() for C# executables, static void main() for java executables) and then passed in to all other classes that are instantiated which require it. This helps you maintain testability.

How can I call PHP functions by JavaScript?

Void Function

<?php
function printMessage() {
    echo "Hello World!";
}
?>

<script>
    document.write("<?php printMessage() ?>");
</script>

Value Returning Function

<?php
function getMessage() {
    return "Hello World!";
}
?>

<script>
    var text = "<?php echo getMessage() ?>";
</script>

JQuery $.ajax() post - data in a java servlet

You don't want a string, you really want a JS map of key value pairs. E.g., change:

 data: myDataVar.toString(),

with:

var myKeyVals = { A1984 : 1, A9873 : 5, A1674 : 2, A8724 : 1, A3574 : 3, A1165 : 5 }



var saveData = $.ajax({
      type: 'POST',
      url: "someaction.do?action=saveData",
      data: myKeyVals,
      dataType: "text",
      success: function(resultData) { alert("Save Complete") }
});
saveData.error(function() { alert("Something went wrong"); });

jQuery understands key value pairs like that, it does NOT understand a big string. It passes it simply as a string.

UPDATE: Code fixed.

PowerShell To Set Folder Permissions

$path = "C:\DemoFolder"
$acl = Get-Acl $path
$username = [System.Security.Principal.WindowsIdentity]::GetCurrent().Name
$Attribs = $username, "FullControl", "ContainerInherit,ObjectInherit", "None", "Allow"
$AccessRule = New-Object System.Security.AcessControl.FileSystemAccessRule($Attribs)
$acl.SetAccessRule($AccessRule)
$acl | Set-Acl $path
Get-ChildItem -Path "$path" -Recourse -Force | Set-Acl -aclObject $acl -Verbose

Scheduling recurring task in Android

Timer

As mentioned on the javadocs you are better off using a ScheduledThreadPoolExecutor.

ScheduledThreadPoolExecutor

Use this class when your use case requires multiple worker threads and the sleep interval is small. How small ? Well, I'd say about 15 minutes. The AlarmManager starts schedule intervals at this time and it seems to suggest that for smaller sleep intervals this class can be used. I do not have data to back the last statement. It is a hunch.

Service

Your service can be closed any time by the VM. Do not use services for recurring tasks. A recurring task can start a service, which is another matter entirely.

BroadcastReciever with AlarmManager

For longer sleep intervals (>15 minutes), this is the way to go. AlarmManager already has constants ( AlarmManager.INTERVAL_DAY ) suggesting that it can trigger tasks several days after it has initially been scheduled. It can also wake up the CPU to run your code.

You should use one of those solutions based on your timing and worker thread needs.

Angular2 QuickStart npm start is not working correctly

  1. In devDependencies typescript is 1.7.3 but you have 1.7.5 fix common one.
  2. Import your js files in the correct order in index.html. for more info refer this repository https://github.com/pkozlowski-opensource/ng2-play/blob/master/index.html or refer to my repository here

    https://github.com/MrPardeep/Angular2-DatePicker

index.html

<script src="node_modules/angular2/bundles/angular2-polyfills.js"></script>
    <script src="node_modules/es6-shim/es6-shim.min.js"></script>
    <script src="node_modules/systemjs/dist/system.src.js"></script>

    <script>
        System.config({
                    defaultJSExtensions: true,
                    map: {
                        rxjs: 'node_modules/rxjs'
                    },
                    packages: {
                        rxjs: {
                        defaultExtension: 'js'
                      }
                    }
                });
    </script>
    <script src="node_modules/angular2/bundles/angular2.dev.js"></script>
    <script src="node_modules/rxjs/bundles/Rx.js"></script>
    <script src="node_modules/angular2/bundles/router.dev.js"></script>
    <script src="node_modules/angular2/bundles/http.dev.js"></script>

<script>
    System.import('dist/bootstrap');
</script> 

How to set Java SDK path in AndroidStudio?

C:\Program Files\Android\Android Studio\jre\bin>java -version
openjdk version "1.8.0_76-release"
OpenJDK Runtime Environment (build 1.8.0_76-release-b03)
OpenJDK 64-Bit Server VM (build 25.76-b03, mixed mode)

Somehow the Studio installer would install another version under:

C:\Program Files\Android\Android Studio\jre\jre\bin>java -version
openjdk version "1.8.0_76-release"
OpenJDK Runtime Environment (build 1.8.0_76-release-b03)
OpenJDK 64-Bit Server VM (build 25.76-b03, mixed mode)

where the latest version was installed the Java DevKit installer in:

C:\Program Files\Java\jre1.8.0_121\bin>java -version
java version "1.8.0_121"
Java(TM) SE Runtime Environment (build 1.8.0_121-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)

Need to clean up the Android Studio so it would use the proper latest 1.8.0 versions.

According to How to set Java SDK path in AndroidStudio? one could override with a specific JDK but when I renamed

C:\Program Files\Android\Android Studio\jre\jre\

to:

C:\Program Files\Android\Android Studio\jre\oldjre\

And restarted Android Studio, it would complain that the jre was invalid. When I tried to aecify an JDK to pick the one in C:\Program Files\Java\jre1.8.0_121\bin or:

C:\Program Files\Java\jre1.8.0_121\

It said that these folders are invalid. So I guess that the embedded version must have some special purpose.

Android RelativeLayout programmatically Set "centerInParent"

I have done for

1. centerInParent

2. centerHorizontal

3. centerVertical

with true and false.

private void addOrRemoveProperty(View view, int property, boolean flag){
    RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
    if(flag){
        layoutParams.addRule(property);
    }else {
        layoutParams.removeRule(property);
    }
    view.setLayoutParams(layoutParams);
}

How to call method:

centerInParent - true

addOrRemoveProperty(mView, RelativeLayout.CENTER_IN_PARENT, true);

centerInParent - false

addOrRemoveProperty(mView, RelativeLayout.CENTER_IN_PARENT, false);

centerHorizontal - true

addOrRemoveProperty(mView, RelativeLayout.CENTER_HORIZONTAL, true);

centerHorizontal - false

addOrRemoveProperty(mView, RelativeLayout.CENTER_HORIZONTAL, false);

centerVertical - true

addOrRemoveProperty(mView, RelativeLayout.CENTER_VERTICAL, true);

centerVertical - false

addOrRemoveProperty(mView, RelativeLayout.CENTER_VERTICAL, false);

Hope this would help you.

How to take a first character from the string

Try this..

Dim S As String
S = "RAJAN"
Dim answer As Char
answer = S.Substring(0, 1)

Could not execute menu item (internal error)[Exception] - When changing PHP version from 5.3.1 to 5.2.9

Maybe an old version of the service was not uninstalled from windows

  1. uninstall the old version running this command line

    sc delete wampapache

  2. Reinstall the service from wamp:

    Wamp Tray Icon -> Apache -> Service -> Install Service

It works for me, enjoy!

Binding select element to object in Angular

This could help:

    <select [(ngModel)]="selectedValue">
          <option *ngFor="#c of countries" [value]="c.id">{{c.name}}</option>
    </select>

How do I change a single value in a data.frame?

In RStudio you can write directly in a cell. Suppose your data.frame is called myDataFrame and the row and column are called columnName and rowName. Then the code would look like:

myDataFrame["rowName", "columnName"] <- value

Hope that helps!

Inline comments for Bash?

For disabling a part of a command like a && b, I simply created an empty script x which is on path, so I can do things like:

mvn install && runProject

when I need to build, and

x mvn install && runProject

when not (using Ctrl + A and Ctrl + E to move to the beginning and end).

As noted in comments, another way to do that is Bash built-in : instead of x:

$  : Hello world, how are you? && echo "Fine."
Fine.

PIG how to count a number of rows in alias

Be careful, with COUNT your first item in the bag must not be null. Else you can use the function COUNT_STAR to count all rows.

Location of Django logs and errors

Logs are set in your settings.py file. A new, default project, looks like this:

# A sample logging configuration. The only tangible logging
# performed by this configuration is to send an email to
# the site admins on every HTTP 500 error when DEBUG=False.
# See http://docs.djangoproject.com/en/dev/topics/logging for
# more details on how to customize your logging configuration.
LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'filters': {
        'require_debug_false': {
            '()': 'django.utils.log.RequireDebugFalse'
        }
    },
    'handlers': {
        'mail_admins': {
            'level': 'ERROR',
            'filters': ['require_debug_false'],
            'class': 'django.utils.log.AdminEmailHandler'
        }
    },
    'loggers': {
        'django.request': {
            'handlers': ['mail_admins'],
            'level': 'ERROR',
            'propagate': True,
        },
    }
}

By default, these don't create log files. If you want those, you need to add a filename parameter to your handlers

    'applogfile': {
        'level':'DEBUG',
        'class':'logging.handlers.RotatingFileHandler',
        'filename': os.path.join(DJANGO_ROOT, 'APPNAME.log'),
        'maxBytes': 1024*1024*15, # 15MB
        'backupCount': 10,
    },

This will set up a rotating log that can get 15 MB in size and keep 10 historical versions.

In the loggers section from above, you need to add applogfile to the handlers for your application

'loggers': {
        'django.request': {
            'handlers': ['mail_admins'],
            'level': 'ERROR',
            'propagate': True,
        },
        'APPNAME': {
            'handlers': ['applogfile',],
            'level': 'DEBUG',
        },
    }

This example will put your logs in your Django root in a file named APPNAME.log

How to check if $? is not equal to zero in unix shell scripting?

Put it in a variable first and then try to test it, as shown below

ret=$?
if [ $ret -ne 0 ]; then
        echo "In If"
else
        echo "In Else"
fi

This should help.


Edit: If the above is not working as expected then, there is a possibility that you are not using $? at right place. It must be the very next line after the command of which you need to catch the return status. Even if there is any other single command in between the target and you catching it's return status, you'll be retrieving the returns_status of this intermediate command and not the one you are expecting.

java.lang.UnsupportedClassVersionError: Bad version number in .class file?

Always check for the obvious too. I got this error once when I accidently grabbed the wrong resource for the server's add and remove action. It can be easy to overlook.

python: sys is not defined

Move import sys outside of the try-except block:

import sys
try:
    # ...
except ImportError:
    # ...

If any of the imports before the import sys line fails, the rest of the block is not executed, and sys is never imported. Instead, execution jumps to the exception handling block, where you then try to access a non-existing name.

sys is a built-in module anyway, it is always present as it holds the data structures to track imports; if importing sys fails, you have bigger problems on your hand (as that would indicate that all module importing is broken).

sed one-liner to convert all uppercase to lowercase?

If you are using posix sed

Selection for any case for a pattern (converting the searched pattern with this sed than use the converted pattern in you wanted command using regex:

echo "${MyOrgPattern} | sed "s/[aA]/[aA]/g;s/[bB]/[bB]/g;s/[cC]/[cC]/g;s/[dD]/[dD]/g;s/[eE]/[eE]/g;s/[fF]/[fF]/g;s/[gG]/[gG]/g;s/[hH]/[hH]/g;s/[iI]/[iI]/g;s/[jJ]/[jJ]/g;s/[kK]/[kK]/g;s/[lL]/[lL]/g;s/[mM]/[mM]/g;s/[nN]/[nN]/g;s/[oO]/[oO]/g;s/[pP]/[pP]/g;s/[qQ]/[qQ]/g;s/[rR]/[rR]/g;s/[sS]/[sS]/g;s/[tT]/[tT]/g;s/[uU]/[uU]/g;s/[vV]/[vV]/g;s/[wW]/[wW]/g;s/[xX]/[xX]/g;s/[yY]/[yY]/g;s/[zZ]/[zZ]/g" | read -c MyNewPattern
 YourInputStreamCommand | egrep "${MyNewPattern}"

convert in lower case

sed "s/[aA]/a/g;s/[bB]/b/g;s/[cC]/c/g;s/[dD]/d/g;s/[eE]/e/g;s/[fF]/f/g;s/[gG]/g/g;s/[hH]/h/g;s/[iI]/i/g;s/j/[jJ]/g;s/[kK]/k/g;s/[lL]/l/g;s/[mM]/m/g;s/[nN]/n/g;s/[oO]/o/g;s/[pP]/p/g;s/[qQ]/q/g;s/[rR]/r/g;s/[sS]/s/g;s/[tT]/t/g;s/[uU]/u/g;s/[vV]/v/g;s/[wW]/w/g;s/[xX]/x/g;s/[yY]/y/g;s/[zZ]/z/g"

same for uppercase replace lower letter between // by upper equivalent in the sed

Have fun

SQL: sum 3 columns when one column has a null value?

looks like you want to SUM all the columns (I'm not sure where "sum 3 columns" comes from), not just TotalHoursM, so try this:

SELECT 
    SUM(    ISNULL(TotalHoursM  ,0)
          + ISNULL(TotalHoursT  ,0)
          + ISNULL(TotalHoursW  ,0)
          + ISNULL(TotalHoursTH ,0)
          + ISNULL(TotalHoursF  ,0) 
       ) AS TOTAL
    FROM LeaveRequest

How to search for a part of a word with ElasticSearch

Searching with leading and trailing wildcards is going to be extremely slow on a large index. If you want to be able to search by word prefix, remove leading wildcard. If you really need to find a substring in a middle of a word, you would be better of using ngram tokenizer.

Finding the mode of a list

For those looking for the minimum mode, e.g:case of bi-modal distribution, using numpy.

import numpy as np
mode = np.argmax(np.bincount(your_list))

nullable object must have a value

Try dropping the .value

DateTimeExtended(DateTimeExtended myNewDT)
{
   this.MyDateTime = myNewDT.MyDateTime;
   this.otherdata = myNewDT.otherdata;
}

In-memory size of a Python structure

Also you can use guppy module.

>>> from guppy import hpy; hp=hpy()
>>> hp.heap()
Partition of a set of 25853 objects. Total size = 3320992 bytes.
 Index  Count   %     Size   % Cumulative  % Kind (class / dict of class)
     0  11731  45   929072  28    929072  28 str
     1   5832  23   469760  14   1398832  42 tuple
     2    324   1   277728   8   1676560  50 dict (no owner)
     3     70   0   216976   7   1893536  57 dict of module
     4    199   1   210856   6   2104392  63 dict of type
     5   1627   6   208256   6   2312648  70 types.CodeType
     6   1592   6   191040   6   2503688  75 function
     7    199   1   177008   5   2680696  81 type
     8    124   0   135328   4   2816024  85 dict of class
     9   1045   4    83600   3   2899624  87 __builtin__.wrapper_descriptor
<90 more rows. Type e.g. '_.more' to view.>

And:

>>> hp.iso(1, [1], "1", (1,), {1:1}, None)
Partition of a set of 6 objects. Total size = 560 bytes.
 Index  Count   %     Size   % Cumulative  % Kind (class / dict of class)
     0      1  17      280  50       280  50 dict (no owner)
     1      1  17      136  24       416  74 list
     2      1  17       64  11       480  86 tuple
     3      1  17       40   7       520  93 str
     4      1  17       24   4       544  97 int
     5      1  17       16   3       560 100 types.NoneType

Start redis-server with config file

Okay, redis is pretty user friendly but there are some gotchas.

Here are just some easy commands for working with redis on Ubuntu:

install:

sudo apt-get install redis-server

start with conf:

sudo redis-server <path to conf>
sudo redis-server config/redis.conf

stop with conf:

redis-ctl shutdown

(not sure how this shuts down the pid specified in the conf. Redis must save the path to the pid somewhere on boot)

log:

tail -f /var/log/redis/redis-server.log

Also, various example confs floating around online and on this site were beyond useless. The best, sure fire way to get a compatible conf is to copy-paste the one your installation is already using. You should be able to find it here:

/etc/redis/redis.conf

Then paste it at <path to conf>, tweak as needed and you're good to go.

Batchfile to create backup and rename with timestamp

Renames all .pdf files based on current system date. For example a file named Gross Profit.pdf is renamed to Gross Profit 2014-07-31.pdf. If you run it tomorrow, it will rename it to Gross Profit 2014-08-01.pdf.

You could replace the ? with the report name Gross Profit, but it will only rename the one report. The ? renames everything in the Conduit folder. The reason there are so many ?, is that some .pdfs have long names. If you just put 12 ?s, then any name longer than 12 characters will be clipped off at the 13th character. Try it with 1 ?, then try it with many ?s. The ? length should be a little longer or as long as the longest report name.

@ECHO OFF
SET NETWORKSOURCE=\\flcorpfile\shared\"SHORE Reports"\2014\Conduit
REN %NETWORKSOURCE%\*.pdf "????????????????????????????????????????????????? %date:~-4,4%-%date:~-10,2%-%date:~7,2%.pdf"

Capture HTML Canvas as gif/jpg/png/pdf?

On some versions of Chrome, you can:

  1. Use the draw image function ctx.drawImage(image1, 0, 0, w, h);
  2. Right-click on the canvas

php: Get html source code with cURL

Try the following:

$ch = curl_init("http://www.example-webpage.com/file.html");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_BINARYTRANSFER, true);
$content = curl_exec($ch);
curl_close($ch);

I would only recommend this for small files. Big files are read as a whole and are likely to produce a memory error.


EDIT: after some discussion in the comments we found out that the problem was that the server couldn't resolve the host name and the page was in addition a HTTPS resource so here comes your temporary solution (until your server admin fixes the name resolving).

what i did is just pinging graph.facebook.com to see the IP address, replace the host name with the IP address and instead specify the header manually. This however renders the SSL certificate invalid so we have to suppress peer verification.

//$url = "https://graph.facebook.com/19165649929?fields=name";
$url = "https://66.220.146.224/19165649929?fields=name";
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_BINARYTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Host: graph.facebook.com'));
$output = curl_exec($ch);
curl_close($ch); 

Keep in mind that the IP address might change and this is an error source. you should also do some error handling using curl_error();.

What is the difference between concurrent programming and parallel programming?

Different people talk about different kinds of concurrency and parallelism in many different specific cases, so some abstractions to cover their common nature are needed.

The basic abstraction is done in computer science, where both concurrency and parallelism are attributed to the properties of programs. Here, programs are formalized descriptions of computing. Such programs need not to be in any particular language or encoding, which is implementation-specific. The existence of API/ABI/ISA/OS is irrelevant to such level of abstraction. Surely one will need more detailed implementation-specific knowledge (like threading model) to do concrete programming works, the spirit behind the basic abstraction is not changed.

A second important fact is, as general properties, concurrency and parallelism can coexist in many different abstractions.

For the general distinction, see the relevant answer for the basic view of concurrency v. parallelism. (There are also some links containing some additional sources.)

Concurrent programming and parallel programming are techniques to implement such general properties with some systems which expose programmability. The systems are usually programming languages and their implementations.

A programming language may expose the intended properties by built-in semantic rules. In most cases, such rules specify the evaluations of specific language structures (e.g. expressions) making the computation involved effectively concurrent or parallel. (More specifically, the computational effects implied by the evaluations can perfectly reflect these properties.) However, concurrent/parallel language semantics are essentially complex and they are not necessary to practical works (to implement efficient concurrent/parallel algorithms as the solutions of realistic problems). So, most traditional languages take a more conservative and simpler approach: assuming the semantics of evaluation totally sequential and serial, then providing optional primitives to allow some of the computations being concurrent and parallel. These primitives can be keywords or procedural constructs ("functions") supported by the language. They are implemented based on the interaction with hosted environments (OS, or "bare metal" hardware interface), usually opaque (not able to be derived using the language portably) to the language. Thus, in this particular kind of high-level abstractions seen by the programmers, nothing is concurrent/parallel besides these "magic" primitives and programs relying on these primitives; the programmers can then enjoy less error-prone experience of programming when concurrency/parallelism properties are not so interested.

Although primitives abstract the complex away in the most high-level abstractions, the implementations still have the extra complexity not exposed by the language feature. So, some mid-level abstractions are needed. One typical example is threading. Threading allows one or more thread of execution (or simply thread; sometimes it is also called a process, which is not necessarily the concept of a task scheduled in an OS) supported by the language implementation (the runtime). Threads are usually preemptively scheduled by the runtime, so a thread needs to know nothing about other threads. Thus, threads are natural to implement parallelism as long as they share nothing (the critical resources): just decompose computations in different threads, once the underlying implementation allows the overlapping of the computation resources during the execution, it works. Threads are also subject to concurrent accesses of shared resources: just access resources in any order meets the minimal constraints required by the algorithm, and the implementation will eventually determine when to access. In such cases, some synchronization operations may be necessary. Some languages treat threading and synchronization operations as parts of the high-level abstraction and expose them as primitives, while some other languages encourage only relatively more high-level primitives (like futures/promises) instead.

Under the level of language-specific threads, there come multitasking of the underlying hosting environment (typically, an OS). OS-level preemptive multitasking are used to implement (preemptive) multithreading. In some environments like Windows NT, the basic scheduling units (the tasks) are also "threads". To differentiate them with userspace implementation of threads mentioned above, they are called kernel threads, where "kernel" means the kernel of the OS (however, strictly speaking, this is not quite true for Windows NT; the "real" kernel is the NT executive). Kernel threads are not always 1:1 mapped to the userspace threads, although 1:1 mapping often reduces most overhead of mapping. Since kernel threads are heavyweight (involving system calls) to create/destroy/communicate, there are non 1:1 green threads in the userspace to overcome the overhead problems at the cost of the mapping overhead. The choice of mapping depending on the programming paradigm expected in the high-level abstraction. For example, when a huge number of userspace threads expected being concurrently executed (like Erlang), 1:1 mapping is never feasible.

The underlying of OS multitasking is ISA-level multitasking provided by the logical core of the processor. This is usually the most low-level public interface for programmers. Beneath this level, there may exist SMT. This is a form of more low-level multithreading implemented by the hardware, but arguably, still somewhat programmable - though it is usually only accessible by the processor manufacturer. Note the hardware design is apparently reflecting parallelism, but there is also concurrent scheduling mechanism to make the internal hardware resources being efficiently used.

In each level of "threading" mentioned above, both concurrency and parallelism are involved. Although the programming interfaces vary dramatically, all of them are subject to the properties revealed by the basic abstraction at the very beginning.

Best way to get user GPS location in background in Android

Use : GCM Network Manager

Run this to start a periodic task that will be ran even after re-boot:

PeriodicTask task = new PeriodicTask.Builder()
    .setService(MyLocationService.class)
    .setTag("periodic")
    .setPeriod(30L)
    .setPersisted(true)
    .build();
mGcmNetworkManager.schedule(task);

then in onRunTask() get current location and use it (in this example, event is submitted at the end to let UI know that location was found):

    public void getLastKnownLocation() {
    Location lastKnownGPSLocation;
    Location lastKnownNetworkLocation;
    String gpsLocationProvider = LocationManager.GPS_PROVIDER;
    String networkLocationProvider = LocationManager.NETWORK_PROVIDER;

    try {
        locationManager = (LocationManager) App.get().getSystemService(Context.LOCATION_SERVICE);

        lastKnownNetworkLocation = locationManager.getLastKnownLocation(networkLocationProvider);
        lastKnownGPSLocation = locationManager.getLastKnownLocation(gpsLocationProvider);

        if (lastKnownGPSLocation != null) {
            Log.i(TAG, "lastKnownGPSLocation is used.");
            this.mCurrentLocation = lastKnownGPSLocation;
        } else if (lastKnownNetworkLocation != null) {
            Log.i(TAG, "lastKnownNetworkLocation is used.");
            this.mCurrentLocation = lastKnownNetworkLocation;
        } else {
            Log.e(TAG, "lastLocation is not known.");
            return;
        }

        LocationChangedEvent event = new LocationChangedEvent();
        event.setLocation(mCurrentLocation);
        EventHelper.publishEvent(event);

    } catch (SecurityException sex) {
        Log.e(TAG, "Location permission is not granted!");
    }

    return;
}

The MyLocationService in whole:

public class MyLocationService extends GcmTaskService {
private static final String TAG = MyLocationService.class.getSimpleName();

private LocationManager locationManager;
private Location mCurrentLocation;

public static final String TASK_GET_LOCATION_ONCE="location_oneoff_task";
public static final String TASK_GET_LOCATION_PERIODIC="location_periodic_task";


private static final int RC_PLAY_SERVICES = 123;

@Override
public void onInitializeTasks() {
    // When your package is removed or updated, all of its network tasks are cleared by
    // the GcmNetworkManager. You can override this method to reschedule them in the case of
    // an updated package. This is not called when your application is first installed.
    //
    // This is called on your application's main thread.
    startPeriodicLocationTask(TASK_GET_LOCATION_PERIODIC,
            30L, null);
}

@Override
public int onRunTask(TaskParams taskParams) {
    Log.d(TAG, "onRunTask: " + taskParams.getTag());

    String tag = taskParams.getTag();
    Bundle extras = taskParams.getExtras();
    // Default result is success.
    int result = GcmNetworkManager.RESULT_SUCCESS;

    switch (tag) {
        case TASK_GET_LOCATION_ONCE:
            getLastKnownLocation();
            break;

        case TASK_GET_LOCATION_PERIODIC:
            getLastKnownLocation();
            break;

    }

    return result;
}


public void getLastKnownLocation() {
    Location lastKnownGPSLocation;
    Location lastKnownNetworkLocation;
    String gpsLocationProvider = LocationManager.GPS_PROVIDER;
    String networkLocationProvider = LocationManager.NETWORK_PROVIDER;

    try {
        locationManager = (LocationManager) App.get().getSystemService(Context.LOCATION_SERVICE);

        lastKnownNetworkLocation = locationManager.getLastKnownLocation(networkLocationProvider);
        lastKnownGPSLocation = locationManager.getLastKnownLocation(gpsLocationProvider);

        if (lastKnownGPSLocation != null) {
            Log.i(TAG, "lastKnownGPSLocation is used.");
            this.mCurrentLocation = lastKnownGPSLocation;
        } else if (lastKnownNetworkLocation != null) {
            Log.i(TAG, "lastKnownNetworkLocation is used.");
            this.mCurrentLocation = lastKnownNetworkLocation;
        } else {
            Log.e(TAG, "lastLocation is not known.");
            return;
        }

        LocationChangedEvent event = new LocationChangedEvent();
        event.setLocation(mCurrentLocation);
        EventHelper.publishEvent(event);

    } catch (SecurityException sex) {
        Log.e(TAG, "Location permission is not granted!");
    }

    return;
}

public static void startOneOffLocationTask(String tag, Bundle extras) {
    Log.d(TAG, "startOneOffLocationTask");

    GcmNetworkManager mGcmNetworkManager = GcmNetworkManager.getInstance(App.get());
    OneoffTask.Builder taskBuilder = new OneoffTask.Builder()
            .setService(MyLocationService.class)
            .setTag(tag);

    if (extras != null) taskBuilder.setExtras(extras);

    OneoffTask task = taskBuilder.build();
    mGcmNetworkManager.schedule(task);
}

public static void startPeriodicLocationTask(String tag, Long period, Bundle extras) {
    Log.d(TAG, "startPeriodicLocationTask");

    GcmNetworkManager mGcmNetworkManager = GcmNetworkManager.getInstance(App.get());
    PeriodicTask.Builder taskBuilder = new PeriodicTask.Builder()
            .setService(MyLocationService.class)
            .setTag(tag)
            .setPeriod(period)
            .setPersisted(true)
            .setRequiredNetwork(Task.NETWORK_STATE_CONNECTED);

    if (extras != null) taskBuilder.setExtras(extras);

    PeriodicTask task = taskBuilder.build();
    mGcmNetworkManager.schedule(task);
}




public static boolean checkPlayServicesAvailable(Activity activity) {
    GoogleApiAvailability availability = GoogleApiAvailability.getInstance();
    int resultCode = availability.isGooglePlayServicesAvailable(App.get());

    if (resultCode != ConnectionResult.SUCCESS) {
        if (availability.isUserResolvableError(resultCode)) {
            // Show dialog to resolve the error.
            availability.getErrorDialog(activity, resultCode, RC_PLAY_SERVICES).show();
        }
        return false;
    } else {
        return true;
    }
}

Also add these 2 to the AndroidManifest.xml:

 <manifest...
 <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

 <application...
 <service
        android:name=".api.location.MyLocationService"
        android:exported="true"
        android:permission="com.google.android.gms.permission.BIND_NETWORK_TASK_SERVICE">
        <intent-filter>
            <action android:name="com.google.android.gms.gcm.ACTION_TASK_READY" />
        </intent-filter>
    </service>

Clear Cache in Android Application programmatically

Kotlin has an one-liner

context.cacheDir.deleteRecursively()

React Router Pass Param to Component

In addition to Alexander Lunas answer ... If you want to add more than one argument just use:

<Route path="/details/:id/:title" component={DetailsPage}/>

export default class DetailsPage extends Component {
  render() {
    return(
      <div>
        <h2>{this.props.match.params.id}</h2>
        <h3>{this.props.match.params.title}</h3>
      </div>
    )
  }
}

C# testing to see if a string is an integer?

I've been coding for about 2 weeks and created a simple logic to validate an integer has been accepted.

    Console.WriteLine("How many numbers do you want to enter?"); // request a number
    string input = Console.ReadLine(); // set the input as a string variable
    int numberTotal; // declare an int variable

    if (!int.TryParse(input, out numberTotal)) // process if input was an invalid number
    {
        while (numberTotal  < 1) // numberTotal is set to 0 by default if no number is entered
        {
            Console.WriteLine(input + " is an invalid number."); // error message
            int.TryParse(Console.ReadLine(), out numberTotal); // allows the user to input another value
        }

    } // this loop will repeat until numberTotal has an int set to 1 or above

you could also use the above in a FOR loop if you prefer by not declaring an action as the third parameter of the loop, such as

    Console.WriteLine("How many numbers do you want to enter?");
    string input2 = Console.ReadLine();

    if (!int.TryParse(input2, out numberTotal2))
    {
        for (int numberTotal2 = 0; numberTotal2 < 1;)
        {
            Console.WriteLine(input2 + " is an invalid number.");
            int.TryParse(Console.ReadLine(), out numberTotal2);
        }

    }

if you don't want a loop, simply remove the entire loop brace

How to change an Android app's name?

There's the android:label for the application, and the android:label for the launch activity. The former is what you see under Settings -> Applications -> Manage Applications on your device. The latter is what you see under Applications, and by extension in any shortcut to your application, e.g.

<application
    android:label="@string/turns_up_in_manage_apps" >
    <activity
        android:name=".MainActivity"
        android:label="@string/turns_up_in_shortcuts" >
        ...
    </activity>
</application>

Efficiently counting the number of lines of a text file. (200mb+)

I use this method for purely counting how many lines in a file. What is the downside of doing this verses the other answers. I'm seeing many lines as opposed to my two line solution. I'm guessing there's a reason nobody does this.

$lines = count(file('your.file'));
echo $lines;

What is the difference between Linear search and Binary search?

binary search runs in O(logn) time whereas linear search runs in O(n) times thus binary search has better performance

Set div height equal to screen size

Use simple CSS height: 100%; matches the height of the parent and using height: 100vh matches the height of the viewport.

Use vh instead of %;

SQL Server procedure declare a list

Alternative to @Peter Monks.

If the number in the 'in' statement is small and fixed.

DECLARE @var1 varchar(30), @var2 varchar(30), @var3  varchar(30);

SET @var1 = 'james';
SET @var2 = 'same';
SET @var3 = 'dogcat';

Select * FROM Database Where x in (@var1,@var2,@var3);

What is the difference between json.dump() and json.dumps() in python?

One notable difference in Python 2 is that if you're using ensure_ascii=False, dump will properly write UTF-8 encoded data into the file (unless you used 8-bit strings with extended characters that are not UTF-8):

dumps on the other hand, with ensure_ascii=False can produce a str or unicode just depending on what types you used for strings:

Serialize obj to a JSON formatted str using this conversion table. If ensure_ascii is False, the result may contain non-ASCII characters and the return value may be a unicode instance.

(emphasis mine). Note that it may still be a str instance as well.

Thus you cannot use its return value to save the structure into file without checking which format was returned and possibly playing with unicode.encode.

This of course is not valid concern in Python 3 any more, since there is no more this 8-bit/Unicode confusion.


As for load vs loads, load considers the whole file to be one JSON document, so you cannot use it to read multiple newline limited JSON documents from a single file.

How do I read the contents of a Node.js stream into a string variable?

I had more luck using like that :

let string = '';
readstream
    .on('data', (buf) => string += buf.toString())
    .on('end', () => console.log(string));

I use node v9.11.1 and the readstream is the response from a http.get callback.

join on multiple columns

The other queries are all going base on any ONE of the conditions qualifying and it will return a record... if you want to make sure the BOTH columns of table A are matched, you'll have to do something like...

select 
      tA.Col1,
      tA.Col2,
      tB.Val
   from
      TableA tA
         join TableB tB
            on  ( tA.Col1 = tB.Col1 OR tA.Col1 = tB.Col2 )
            AND ( tA.Col2 = tB.Col1 OR tA.Col2 = tB.Col2 )

Pressing Ctrl + A in Selenium WebDriver

Actions act = new Actions(driver);
act.keyDown(Keys.CONTROL).sendKeys("a").keyUp(Keys.CONTROL).build().perform();

how to check if object already exists in a list

Another point to mention is that you should ensure that your equality function is as you expect. You should override the equals method to set up what properties of your object have to match for two instances to be considered equal.

Then you can just do mylist.contains(item)

How to extract or unpack an .ab file (Android Backup file)

I have had to unpack a .ab-file, too and found this post while looking for an answer. My suggested solution is Android Backup Extractor, a free Java tool for Windows, Linux and Mac OS.

Make sure to take a look at the README, if you encounter a problem. You might have to download further files, if your .ab-file is password-protected.

Usage:
java -jar abe.jar [-debug] [-useenv=yourenv] unpack <backup.ab> <backup.tar> [password]

Example:

Let's say, you've got a file test.ab, which is not password-protected, you're using Windows and want the resulting .tar-Archive to be called test.tar. Then your command should be:

java.exe -jar abe.jar unpack test.ab test.tar ""

Get the last 4 characters of a string

str = "aaaaabbbb"
newstr = str[-4:]

See : http://codepad.org/S3zjnKoD

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

You could have a redirect servlet. In you web.xml you'd have:

<servlet>
    <servlet-name>images</servlet-name>
    <servlet-class>com.example.images.ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>images</servlet-name>
    <url-pattern>/images/*</url-pattern>
</servlet-mapping>

All your images would be in "/images", which would be intercepted by the servlet. It would then read in the relevant file in whatever folder and serve it right back out. For example, say you have a gif in your images folder, c:\Server_Images\smilie.gif. In the web page would be <img src="http:/example.com/app/images/smilie.gif".... In the servlet, HttpServletRequest.getPathInfo() would yield "/smilie.gif". Which the servlet would find in the folder.