Programs & Examples On #Objectify

Objectify is a 3rd party Java data access API specifically designed for Google Cloud Datastore in the App Engine Standard runtime. It occupies a "middle ground"; easier to use and more transparent than JDO or JPA, but significantly more convenient than the Low-Level API provided for Cloud Datastore.

Error:Execution failed for task ':app:dexDebug'.

I am adding it so that someone in a similar situation might find it helpful.

So, even after multiDexEnabled = true I was getting the same error. I had no duplicate libraries. None of the above solutions worked. Upon reading the error log, I found OutOfMemError issue to be the primary reason and thought of changing the heap size somehow. Hence, this -

dexOptions {
        preDexLibraries = false
        javaMaxHeapSize "4g"

Where "4g" means HeapSize of 4 GB. And it worked! I hope it does for you too.

How to convert an XML file to nice pandas dataframe?

Here is another way of converting a xml to pandas data frame. For example i have parsing xml from a string but this logic holds good from reading file as well.

import pandas as pd
import xml.etree.ElementTree as ET

xml_str = '<?xml version="1.0" encoding="utf-8"?>\n<response>\n <head>\n  <code>\n   200\n  </code>\n </head>\n <body>\n  <data id="0" name="All Categories" t="2018052600" tg="1" type="category"/>\n  <data id="13" name=" [H]" t="2018052600" tg="1" type="publication"/>\n </body>\n</response>'

etree = ET.fromstring(xml_str)
dfcols = ['id', 'name']
df = pd.DataFrame(columns=dfcols)

for i in etree.iter(tag='data'):
    df = df.append(
        pd.Series([i.get('id'), i.get('name')], index=dfcols),


pip is not able to install packages correctly: Permission denied error

On a Mac, you need to use this command:

STATIC_DEPS=true sudo pip install lxml

SyntaxError of Non-ASCII character

You should define source code encoding, add this to the top of your script:

# -*- coding: utf-8 -*-

The reason why it works differently in console and in the IDE is, likely, because of different default encodings set. You can check it by running:

import sys
print sys.getdefaultencoding()

Also see:

Why should we typedef a struct so often in C?

A> a typdef aids in the meaning and documentation of a program by allowing creation of more meaningful synonyms for data types. In addition, they help parameterize a program against portability problems (K&R, pg147, C prog lang).

B> a structure defines a type. Structs allows convenient grouping of a collection of vars for convenience of handling (K&R, pg127, C prog lang.) as a single unit

C> typedef'ing a struct is explained in A above.

D> To me, structs are custom types or containers or collections or namespaces or complex types, whereas a typdef is just a means to create more nicknames.

Text-align class for inside a table

Here is a short and sweet answer with an example.

    width: 100%;_x000D_
table td, table th {_x000D_
    border: 1px solid #000;_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<link href="" rel="stylesheet"/>_x000D_
      <th class="text-left">Text align left.</th>_x000D_
      <th class="text-center">Text align center.</th>_x000D_
      <th class="text-right">Text align right.</th>_x000D_
      <td class="text-left">Text align left.</td>_x000D_
      <td class="text-center">Text align center.</td>_x000D_
      <td class="text-right">Text align right.</td>_x000D_

Combining C++ and C - how does #ifdef __cplusplus work?

  1. extern "C" doesn't change the presence or absence of the __cplusplus macro. It just changes the linkage and name-mangling of the wrapped declarations.

  2. You can nest extern "C" blocks quite happily.

  3. If you compile your .c files as C++ then anything not in an extern "C" block, and without an extern "C" prototype will be treated as a C++ function. If you compile them as C then of course everything will be a C function.

  4. Yes

  5. You can safely mix C and C++ in this way.

stringstream, string, and char* conversion confusion

stringstream.str() returns a temporary string object that's destroyed at the end of the full expression. If you get a pointer to a C string from that (stringstream.str().c_str()), it will point to a string which is deleted where the statement ends. That's why your code prints garbage.

You could copy that temporary string object to some other string object and take the C string from that one:

const std::string tmp = stringstream.str();
const char* cstr = tmp.c_str();

Note that I made the temporary string const, because any changes to it might cause it to re-allocate and thus render cstr invalid. It is therefor safer to not to store the result of the call to str() at all and use cstr only until the end of the full expression:

use_c_str( stringstream.str().c_str() );

Of course, the latter might not be easy and copying might be too expensive. What you can do instead is to bind the temporary to a const reference. This will extend its lifetime to the lifetime of the reference:

  const std::string& tmp = stringstream.str();   
  const char* cstr = tmp.c_str();

IMO that's the best solution. Unfortunately it's not very well known.

How to play an android notification sound

If anyone's still looking for a solution to this, I found an answer at How to play ringtone/alarm sound in Android

try {
    Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
    Ringtone r = RingtoneManager.getRingtone(getApplicationContext(), notification);;
} catch (Exception e) {

You can change TYPE_NOTIFICATION to TYPE_ALARM, but you'll want to keep track of your Ringtone r in order to stop playing it... say, when the user clicks a button or something.

Android Error [Attempt to invoke virtual method 'void' on a null object reference]

You should try this one. I think it will work.

    Toolbar toolbar = findViewById(;

    mDrawerLayout = findViewById(;
    mDrawerLayout = findViewById(;

    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
            toolbar, R.string.navigation_drawer_close,
            R.string.navigation_drawer_close) {
        public void onDrawerClosed(View view) {

        public void onDrawerOpened(View drawerView) {

What is a "callback" in C and how are they implemented?

This wikipedia article has an example in C.

A good example is that new modules written to augment the Apache Web server register with the main apache process by passing them function pointers so those functions are called back to process web page requests.

What are ABAP and SAP?

SAP is really a big Company that offers incredible solutions oriented to medium-large companies.

Actually, I can say that the main IT products are: ERP, WEB, Human Resources, Integration, BI, Reports, Machine Learning, Mobile, Cloud, Robotics, and so on.

On the cloud, you can even find solutions using Cloud Foundry, NodeJS, HTML5, Java, etc.

It's really huge the solutions that offers to their customers.

SQL LEFT JOIN Subquery Alias

I recognize that the answer works and has been accepted but there is a much cleaner way to write that query. Tested on mysql and postgres.

SELECT wpoi.order_id As No_Commande
FROM  wp_woocommerce_order_items AS wpoi
LEFT JOIN wp_postmeta AS wpp ON wpoi.order_id = wpp.post_id 
                            AND wpp.meta_key = '_shipping_first_name'
WHERE  wpoi.order_id =2198 

Android Studio AVD - Emulator: Process finished with exit code 1

Check android studio event log as it could be low storage issue.

emulator: ERROR: Not enough disk space to run AVD 'Nexus_5_API_21'. Exiting...

How to put a UserControl into Visual Studio toolBox

The issue with my designer was 32 vs 64 bit issue. I could add the control to tool box after following the instructions in Cannot add Controls from 64-bit Assemblies to the Toolbox or Use in Designers Within the Visual Studio IDE MS KB article.

Array.sort() doesn't sort numbers correctly

try this:

a = new Array();


function Test(a,b)
    return a > b ? true : false;

How to access a value defined in the file in Spring Boot

You can use the @Value annotation and access the property in whichever Spring bean you're using

private String userBucketPath;

The Externalized Configuration section of the Spring Boot docs, explains all the details that you might need.

how to delete all cookies of my website in php

PHP setcookie()

Taken from that page, this will unset all of the cookies for your domain:

// unset cookies
if (isset($_SERVER['HTTP_COOKIE'])) {
    $cookies = explode(';', $_SERVER['HTTP_COOKIE']);
    foreach($cookies as $cookie) {
        $parts = explode('=', $cookie);
        $name = trim($parts[0]);
        setcookie($name, '', time()-1000);
        setcookie($name, '', time()-1000, '/');

How to randomize Excel rows

I usually do as you describe:
Add a separate column with a random value (=RAND()) and then perform a sort on that column.

Might be more complex and prettyer ways (using macros etc), but this is fast enough and simple enough for me.

Command line tool to dump Windows DLL version?

You can write a VBScript script to get the file version info:


set args = WScript.Arguments
Set fso = CreateObject("Scripting.FileSystemObject")
WScript.Echo fso.GetFileVersion(args(0))

You can call this from the command line like this:

cscript //nologo VersionInfo.vbs C:\Path\To\MyFile.dll

How to detect window.print() finish

See As a workaround, you can listen for the afterPrint event on the window (Firefox and IE) and listen for mouse movement on the document (indicating that the user has closed the print dialog and returned to the page) after the window.mediaMatch API indicates that the media no longer matches "print" (Firefox and Chrome).

Keep in mind that the user may or may not have actually printed the document. Also, if you call window.print() too often in Chrome, the user may not have even been prompted to print.

How to add parameters into a WebRequest?

Hope this works

webRequest.Credentials= new NetworkCredential("API_User","API_Password");

Property '...' has no initializer and is not definitely assigned in the constructor

I think you are using the latest version of TypeScript. Please see the section "Strict Class Initialization" in the link.

There are two ways to fix this:

A. If you are using VSCode you need to change the TS version that the editor use.

B. Just initialize the array when you declare it inside the constructor,

makes: any[] = [];

constructor(private makeService: MakeService) { 
   // Initialization inside the constructor
   this.makes = [];

What is the difference between SAX and DOM?

Well, you are close.

In SAX, events are triggered when the XML is being parsed. When the parser is parsing the XML, and encounters a tag starting (e.g. <something>), then it triggers the tagStarted event (actual name of event might differ). Similarly when the end of the tag is met while parsing (</something>), it triggers tagEnded. Using a SAX parser implies you need to handle these events and make sense of the data returned with each event.

In DOM, there are no events triggered while parsing. The entire XML is parsed and a DOM tree (of the nodes in the XML) is generated and returned. Once parsed, the user can navigate the tree to access the various data previously embedded in the various nodes in the XML.

In general, DOM is easier to use but has an overhead of parsing the entire XML before you can start using it.

Access Controller method from another controller in Laravel 5

You can access the controller by instantiating it and calling doAction: (put use Illuminate\Support\Facades\App; before the controller class declaration)

$controller = App::make('\App\Http\Controllers\YouControllerName');
$data = $controller->callAction('controller_method', $parameters);

Also note that by doing this you will not execute any of the middlewares declared on that controller.

Updates were rejected because the tip of your current branch is behind hint: its remote counterpart. Integrate the remote changes (e.g

You need to merge the remote branch into your current branch by running git pull.

If your local branch is already up-to-date, you may also need to run git pull --rebase.

A quick google search also turned up this same question asked by another SO user: Cannot push to GitHub - keeps saying need merge. More details there.

Converting File to MultiPartFile

Solution without Mocking class, Java9+ and Spring only.

FileItem fileItem = new DiskFileItemFactory().createItem("file",
    Files.probeContentType(file.toPath()), false, file.getName());

try (InputStream in = new FileInputStream(file); OutputStream out = fileItem.getOutputStream()) {
} catch (Exception e) {
    throw new IllegalArgumentException("Invalid file: " + e, e);

CommonsMultipartFile multipartFile = new CommonsMultipartFile(fileItem);

How can I use JavaScript in Java?

Java includes a scripting language extension package starting with version 6.

See the Rhino project documentation for embedding a JavaScript interpreter in Java.


Here is a small example of how you can expose Java objects to your interpreted script:

public class JS {
  public static void main(String args[]) throws Exception {
    ScriptEngine js = new ScriptEngineManager().getEngineByName("javascript");
    Bindings bindings = js.getBindings(ScriptContext.ENGINE_SCOPE);
    bindings.put("stdout", System.out);
    // Prints "-1.0" to the standard output stream.

How do I increase the contrast of an image in Python OpenCV

Best explanation for X = aY + b (in fact it f(x) = ax + b)) is provided at

A Simpler one by just adjusting lightness/luma/brightness for contrast as is below:

import cv2

img = cv2.imread('test.jpg')
cv2.imshow('test', img)
imghsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)

imghsv[:,:,2] = [[max(pixel - 25, 0) if pixel < 190 else min(pixel + 25, 255) for pixel in row] for row in imghsv[:,:,2]]
cv2.imshow('contrast', cv2.cvtColor(imghsv, cv2.COLOR_HSV2BGR))

Perform commands over ssh with Python

Asking User to enter the command as per the device they are logging in.
The below code is validated by

import paramiko
import xlrd
import time

ssh = paramiko.SSHClient()
loc = ('/Users/harshgow/Documents/PYTHON_WORK/labcred.xlsx')
wo = xlrd.open_workbook(loc)
sheet = wo.sheet_by_index(0)
Host = sheet.cell_value(0, 1)
Port = int(sheet.cell_value(3, 1))
User = sheet.cell_value(1, 1)
Pass = sheet.cell_value(2, 1)

def details(Host, Port, User, Pass):
    ssh.connect(Host, Port, User, Pass)
    print('connected to ip ', Host)
    stdin, stdout, stderr = ssh.exec_command("")
    x = input('Enter the command:')

details(Host, Port, User, Pass)

Parse JSON String to JSON Object in C#.NET

Since you mentioned that you are using Newtonsoft.dll you can convert a JSON string to an object by using its facilities:

MyClass myClass = JsonConvert.DeserializeObject<MyClass>(your_json_string);

public class MyClass
    public string myVar {get; set;}

Propagation Delay vs Transmission delay

Transmission Delay : Amount of time required to pump all bits/packets into the electric wire/optic fibre.

Propagation delay : It's the amount of time needed for a packet to reach the destination.

If propagation delay is very high than transmission delay the chance of losing the packet is high.

What happens if you mount to a non-empty mount point with fuse?

Apparently nothing happens, it fails in a non-destructive way and gives you a warning.

I've had this happen as well very recently. One way you can solve this is by moving all the files in the non-empty mount point to somewhere else, e.g.:

mv /nonEmptyMountPoint/* ~/Desktop/mountPointDump/

This way your mount point is now empty, and your mount command will work.

How to resolve "must be an instance of string, string given" prior to PHP 7?

From PHP's manual :

Type Hints can only be of the object and array (since PHP 5.1) type. Traditional type hinting with int and string isn't supported.

So you have it. The error message is not really helpful, I give you that though.

** 2017 Edit **

PHP7 introduced more function data type declarations, and the aforementioned link has been moved to Function arguments : Type declarations. From that page :

Valid types

  • Class/interface name : The parameter must be an instanceof the given class or interface name. (since PHP 5.0.0)
  • self : The parameter must be an instanceof the same class as the one the method is defined on. This can only be used on class and instance methods. (since PHP 5.0.0)
  • array : The parameter must be an array. (since PHP 5.1.0)
  • callable : The parameter must be a valid callable. (since PHP 5.4.0)
  • bool : The parameter must be a boolean value. (since PHP 7.0.0)
  • float : The parameter must be a floating point number. (since PHP 7.0.0)
  • int : The parameter must be an integer. (since PHP 7.0.0)
  • string : The parameter must be a string. (since PHP 7.0.0)
  • iterable : The parameter must be either an array or an instanceof Traversable. (since PHP 7.1.0)


Aliases for the above scalar types are not supported. Instead, they are treated as class or interface names. For example, using boolean as a parameter or return type will require an argument or return value that is an instanceof the class or interface boolean, rather than of type bool:

  function test(boolean $param) {}

The above example will output:

 Fatal error: Uncaught TypeError: Argument 1 passed to test() must be an instance of boolean, boolean given, called in - on line 1 and defined in -:1

The last warning is actually significant to understand the error "Argument must of type string, string given"; since mostly only class/interface names are allowed as argument type, PHP tries to locate a class name "string", but can't find any because it is a primitive type, thus fail with this awkward error.

Where is the itoa function in Linux?

Where is the itoa function in Linux?

There is no such function in Linux. I use this code instead.


Convert integer to string

- value     A 64-bit number to convert
- str       Destination buffer; should be 66 characters long for radix2, 24 - radix8, 22 - radix10, 18 - radix16.
- radix     Radix must be in range -36 .. 36. Negative values used for signed numbers.

char* itoa (unsigned long long  value,  char str[],  int radix)
    char        buf [66];
    char*       dest = buf + sizeof(buf);
    boolean     sign = false;

    if (value == 0) {
        memcpy (str, "0", 2);
        return str;

    if (radix < 0) {
        radix = -radix;
        if ( (long long) value < 0) {
            value = -value;
            sign = true;

    *--dest = '\0';

    switch (radix)
    case 16:
        while (value) {
            * --dest = '0' + (value & 0xF);
            if (*dest > '9') *dest += 'A' - '9' - 1;
            value >>= 4;
    case 10:
        while (value) {
            *--dest = '0' + (value % 10);
            value /= 10;

    case 8:
        while (value) {
            *--dest = '0' + (value & 7);
            value >>= 3;

    case 2:
        while (value) {
            *--dest = '0' + (value & 1);
            value >>= 1;

    default:            // The slow version, but universal
        while (value) {
            *--dest = '0' + (value % radix);
            if (*dest > '9') *dest += 'A' - '9' - 1;
            value /= radix;

    if (sign) *--dest = '-';

    memcpy (str, dest, buf +sizeof(buf) - dest);
    return str;

Java - using System.getProperty("user.dir") to get the home directory

Program to get the current working directory=user.dir

public class CurrentDirectoryExample {

    public static void main(String args[]) {

        String current = System.getProperty("user.dir");
        System.out.println("Current working directory in Java : " + current);

How to conditionally take action if FINDSTR fails to find a string

You are not evaluating a condition for the IF. I am guessing you want to not copy if you find stringToCheck in fileToCheck. You need to do something like (code untested but you get the idea):

CD C:\MyFolder
findstr /c:"stringToCheck" fileToCheck.bat
IF NOT ERRORLEVEL 0 XCOPY "C:\OtherFolder\fileToCheck.bat" "C:\MyFolder" /s /y

EDIT by dbenham
The above test is WRONG, it always evaluates to FALSE.
The correct test is IF ERRORLEVEL 1 XCOPY ...

Update: I can't test the code, but I am not sure what return value findstr actually returns if it doesn't find anything. You might have to do something like:

CD C:\MyFolder
findstr /c:"stringToCheck" fileToCheck.bat > tempfindoutput.txt
set /p FINDOUTPUT= < tempfindoutput.txt
IF "%FINDOUTPUT%"=="" XCOPY "C:\OtherFolder\fileToCheck.bat" "C:\MyFolder" /s /y
del tempfindoutput.txt

Getting the class name from a static method in Java

In order to support refactoring correctly (rename class), then you should use either:

 MyClass.class.getName(); // full name with package

or (thanks to @James Van Huis):

 MyClass.class.getSimpleName(); // class name and no more

How do I split a string on a delimiter in Bash?

This worked for me:

echo $string | cut -d';' -f1 # output is 1
echo $string | cut -d';' -f2 # output is 2

How do I determine whether my calculation of pi is accurate?

Undoubtedly, for your purposes (which I assume is just a programming exercise), the best thing is to check your results against any of the listings of the digits of pi on the web.

And how do we know that those values are correct? Well, I could say that there are computer-science-y ways to prove that an implementation of an algorithm is correct.

More pragmatically, if different people use different algorithms, and they all agree to (pick a number) a thousand (million, whatever) decimal places, that should give you a warm fuzzy feeling that they got it right.

Historically, William Shanks published pi to 707 decimal places in 1873. Poor guy, he made a mistake starting at the 528th decimal place.

Very interestingly, in 1995 an algorithm was published that had the property that would directly calculate the nth digit (base 16) of pi without having to calculate all the previous digits!

Finally, I hope your initial algorithm wasn't pi/4 = 1 - 1/3 + 1/5 - 1/7 + ... That may be the simplest to program, but it's also one of the slowest ways to do so. Check out the pi article on Wikipedia for faster approaches.

Detecting input change in jQuery?

If you want the event to be fired whenever something is changed within the element then you could use the keyup event.

Explaining the 'find -mtime' command

To find all files modified in the last 24 hours use the one below. The -1 here means changed 1 day or less ago.

find . -mtime -1 -ls

What is the difference between PUT, POST and PATCH?

Main Difference Between PUT and PATCH Requests:

Suppose we have a resource that holds the first name and last name of a person.

If we want to change the first name then we send a put request for Update

{ "first": "Michael", "last": "Angelo" }

Here, although we are only changing the first name, with PUT request we have to send both parameters first and last.
In other words, it is mandatory to send all values again, the full payload.

When we send a PATCH request, however, we only send the data which we want to update. In other words, we only send the first name to update, no need to send the last name.

ObservableCollection Doesn't support AddRange method, so I get notified for each item added, besides what about INotifyCollectionChanging?

Proof of need for OnPropertyChanged("Count") and OnPropertyChanged("Item[]") calls in order to behave as per ObservableCollection. Note that I don't know what the consequences are if you don't bother!

Here is a test method that shows that there are two PropertyChange events for each add in a normal observable collection. One for "Count" and one for "Item[]".

public void TestAddSinglesInOldObsevableCollection()
  int colChangedEvents = 0;
  int propChangedEvents = 0;
  var collection = new ObservableCollection<object>();
  collection.CollectionChanged += (sender, e) => { colChangedEvents++; };
  (collection as INotifyPropertyChanged).PropertyChanged += (sender, e) => { propChangedEvents++; };
  collection.Add(new object());
  collection.Add(new object());
  collection.Add(new object());
  Assert.AreEqual(3, colChangedEvents);
  Assert.AreEqual(6, propChangedEvents);

@Shimmy , swap the standard for your collection and change to an add range and you will get zero PropertyChanges. Note that collection change does work fine, but not doing exactly what ObservableCollection does. So Test for shimmy collection looks like this:

public void TestShimmyAddRange()
  int colChangedEvents = 0;
  int propChangedEvents = 0;
  var collection = new ShimmyObservableCollection<object>();
  collection.CollectionChanged += (sender, e) => { colChangedEvents++; };
  (collection as INotifyPropertyChanged).PropertyChanged += (sender, e) => { propChangedEvents++; };
    new object(), new object(), new object(), new object()}); //4 objects at once
  Assert.AreEqual(1, colChangedEvents);  //great, just one!
  Assert.AreEqual(2, propChangedEvents); //fails, no events :(

FYI here is code from InsertItem (also called by Add) from ObservableCollection:

protected override void InsertItem(int index, T item)
  base.InsertItem(index, item);
  base.OnCollectionChanged(NotifyCollectionChangedAction.Add, item, index);

how to display a javascript var in html body

<script type="text/javascript">_x000D_
        function get_param(param) {_x000D_
   var search =;_x000D_
   var compareKeyValuePair = function(pair) {_x000D_
      var key_value = pair.split('=');_x000D_
      var decodedKey = decodeURIComponent(key_value[0]);_x000D_
      var decodedValue = decodeURIComponent(key_value[1]);_x000D_
      if(decodedKey == param) return decodedValue;_x000D_
      return null;_x000D_
   var comparisonResult = null;_x000D_
   if(search.indexOf('&') > -1) {_x000D_
      var params = search.split('&');_x000D_
      for(var i = 0; i < params.length; i++) {_x000D_
         comparisonResult = compareKeyValuePair(params[i]); _x000D_
         if(comparisonResult !== null) {_x000D_
   } else {_x000D_
      comparisonResult = compareKeyValuePair(search);_x000D_
   return comparisonResult;_x000D_
var parcelNumber = get_param('parcelNumber'); //abc_x000D_
var registryId  = get_param('registryId'); //abc_x000D_
var registrySectionId = get_param('registrySectionId'); //abc_x000D_
var apartmentNumber = get_param('apartmentNumber'); //abc_x000D_

then in the page i call the values like so:

 <td class="tinfodd"> <script  type="text/javascript">_x000D_

SQL Query - Concatenating Results into One String

If you're on SQL Server 2005 or up, you can use this FOR XML PATH & STUFF trick:

DECLARE @CodeNameString varchar(100)

   @CodeNameString = STUFF( (SELECT ',' + CodeName 
                             FROM dbo.AccountCodes 
                             ORDER BY Sort
                             FOR XML PATH('')), 
                            1, 1, '')

The FOR XML PATH('') basically concatenates your strings together into one, long XML result (something like ,code1,code2,code3 etc.) and the STUFF puts a "nothing" character at the first character, e.g. wipes out the "superfluous" first comma, to give you the result you're probably looking for.

UPDATE: OK - I understand the comments - if your text in the database table already contains characters like <, > or &, then my current solution will in fact encode those into &lt;, &gt;, and &amp;.

If you have a problem with that XML encoding - then yes, you must look at the solution proposed by @KM which works for those characters, too. One word of warning from me: this approach is a lot more resource and processing intensive - just so you know.

How to install OpenSSL in windows 10?

Either set the openssl present in Git as your default openssl and include that into your path in environmental variables (quick way)


  1. Install the system-specific openssl from this link.
  2. set the following variable : set OPENSSL_CONF=LOCATION_OF_SSL_INSTALL\bin\openssl.cfg
  3. Update the path : set Path=...Other Values here...;LOCATION_OF_SSL_INSTALL\bin

How to execute logic on Optional if not present?

First of all, your dao.find() should either return an Optional<Obj> or you will have to create one.


Optional<Obj> = dao.find();

or you can do it yourself like:

Optional<Obj> = Optional.ofNullable(dao.find());

this one will return Optional<Obj> if present or Optional.empty() if not present.

So now let's get to the solution,

public Obj getObjectFromDB() {
   return Optional.ofNullable(dao.find()).flatMap(ob -> {
            return Optional.of(ob);    
        }).orElseGet(() -> {
            logger.fatal("Object not available");
            return null;

This is the one liner you're looking for :)

How to show android checkbox at right side?

Just copy this:

            android:text="Your text:"/>

Happy codding! :)

How to clear jQuery validation error messages?

I think we just need to enter the inputs to clean everything

$("#your_div").click(function() {

Definitive way to trigger keypress events with jQuery

I made it work with keyup.

$("#id input").trigger('keyup');

C++: Where to initialize variables in constructor

Option 1 allows you to initialize const members. This cannot be done with option 2 (as they are assigned to, not initialized).

Why must const members be intialized in the constructor initializer rather than in its body?

MAMP mysql server won't start. No mysql processes are running

I was running MAMP 4.1 on windows and MYSQL 5.7 .Was having this problem many times and found out a fix for this: For me deleting the log files was not working then just delete

  • mysql-bin.index

and boom it starts working again. If this also doesn't work for your, remember to delete each file one by one and keep checking if any works for you. Make sure to backup always.

How to remove multiple deleted files in Git repository

Another version to ByScripts answer is

git rm $(git ls-files --deleted)

This will ONLY remove the deleted files from the git.

It could be also be used for adding ONLY modified files also.

git add $(git ls-files --modified)

These commands also works on gitbash for windows.

Understanding repr( ) function in Python

When you say

foo = 'bar'

you are not passing foo to the baz function. foo is just a name used to represent a value, in this case 'bar', and that value is passed to the baz function.

Using sed to split a string with a delimiter

Using simply :

$ tr ':' $'\n' <<< string1:string2:string3:string4:string5

If you really need :

$ sed 's/:/\n/g' <<< string1:string2:string3:string4:string5

Pandas - replacing column values

Yes, you are using it incorrectly, Series.replace() is not inplace operation by default, it returns the replaced dataframe/series, you need to assign it back to your dataFrame/Series for its effect to occur. Or if you need to do it inplace, you need to specify the inplace keyword argument as True Example -

data['sex'].replace(0, 'Female',inplace=True)
data['sex'].replace(1, 'Male',inplace=True)

Also, you can combine the above into a single replace function call by using list for both to_replace argument as well as value argument , Example -


Example/Demo -

In [10]: data = pd.DataFrame([[1,0],[0,1],[1,0],[0,1]], columns=["sex", "split"])

In [11]: data['sex'].replace([0,1],['Female','Male'],inplace=True)

In [12]: data
      sex  split
0    Male      0
1  Female      1
2    Male      0
3  Female      1

You can also use a dictionary, Example -

In [15]: data = pd.DataFrame([[1,0],[0,1],[1,0],[0,1]], columns=["sex", "split"])

In [16]: data['sex'].replace({0:'Female',1:'Male'},inplace=True)

In [17]: data
      sex  split
0    Male      0
1  Female      1
2    Male      0
3  Female      1

Why I'm getting 'Non-static method should not be called statically' when invoking a method in a Eloquent model?

For use the syntax like return Post::getAll(); you should have a magic function __callStatic in your class where handle all static calls:

public static function __callStatic($method, $parameters)
    return (new static)->$method(...$parameters);

How to fix the error; 'Error: Bootstrap tooltips require Tether ('

I was having this issue with requirejs using the newest boostrap 4 build. I ended up just defining:

  window.Tether = {};

in my html head tag to fool bootstrap's check. I then added a second require statement just before the require that loads my app, and subsequently, my bootstrap dependency:

require(['tether'], function (Tether) {
  window.Tether = Tether;

], function(App){

Using both of these in tandem and you should have no problem using current bootstrap 4 alpha build.

Unable to send email using Gmail SMTP server through PHPMailer, getting error: SMTP AUTH is required for message submission on port 587. How to fix?

 $mail->SMTPOptions = array(
                'ssl' => array(
                    'verify_peer' => false,
                    'verify_peer_name' => false,
                    'allow_self_signed' => true

Bootstrap how to get text to vertical align in a div container

  transform: translateY(-50%);
  -webkit-transform: translateY(-50%);
  -ms-transform: translateY(-50%);


The top:50% style essentially pushes the header element down 50% from the top of the parent element. The translateY stylings also act in a similar manner by moving then element down 50% from the top.

Please note that this works well for headers with 1 (maybe 2) lines of text as this simply moves the top of the header element down 50% and then the rest of the content fills in below that, which means that with multiple lines of text it would appear to be slightly below vertically aligned.

A possible fix for multiple lines would be to use a percentage slightly less than 50%.

How to scp in Python?

I don't think there's any one module that you can easily download to implement scp, however you might find this helpful:

Angular 2 - NgFor using numbers instead collections

I couldn't bear the idea of allocating an array for plain repeat of components, so I've written a structural directive. In simplest form, that doesn't make the index available to the template, it looks like this:

import { Directive, Input, TemplateRef, ViewContainerRef } from '@angular/core';

@Directive({ selector: '[biRepeat]' })
export class RepeatDirective {

  constructor( private templateRef: TemplateRef<any>,
             private viewContainer: ViewContainerRef) { }

  @Input('biRepeat') set count(c:number) {
    for(var i=0;i<c;i++) {

How can I use LTRIM/RTRIM to search and replace leading/trailing spaces?

I understand this question is for sql server 2012, but if the same scenario for SQL Server 2017 or SQL Azure you can use Trim directly as below:

UPDATE *tablename*
   SET *columnname* = trim(*columnname*);

Is there a MessageBox equivalent in WPF?

Maybe the code here below helps:

using Windows.UI.Popups;
namespace something.MyViewModels
    public class TestViewModel
        public void aRandonMethode()

        public async void MyMessageBox(string mytext)
            var dialog = new MessageDialog(mytext);
            await dialog.ShowAsync();

How to install python3 version of package via pip on Ubuntu?

Firstly, you need to install pip for the Python 3 installation that you want. Then you run that pip to install packages for that Python version.

Since you have both pip and python 3 in /usr/bin, I assume they are both installed with a package manager of some sort. That package manager should also have a Python 3 pip. That's the one you should install.

Felix' recommendation of virtualenv is a good one. If you are only testing, or you are doing development, then you shouldn't install the package in the system python. Using virtualenv, or even building your own Pythons for development, is better in those cases.

But if you actually do want to install this package in the system python, installing pip for Python 3 is the way to go.

Combine hover and click functions (jQuery)?

You could also use bind:

$('#myelement').bind('click hover', function yourCommonHandler (e) {
   // Your handler here

Showing loading animation in center of page while making a call to Action method in ASP .NET MVC

Another solution that it is similar to those already exposed here is this one. Just before the closing body tag place this html:

<div id="resultLoading" style="display: none; width: 100%; height: 100%; position: fixed; z-index: 10000; top: 0px; left: 0px; right: 0px; bottom: 0px; margin: auto;">
    <div style="width: 340px; height: 200px; text-align: center; position: fixed; top: 0px; left: 0px; right: 0px; bottom: 0px; margin: auto; z-index: 10; color: rgb(255, 255, 255);">
        <div class="uil-default-css">
            <img src="/images/loading-animation1.gif" style="max-width: 150px; max-height: 150px; display: block; margin-left: auto; margin-right: auto;" />
        <div class="loader-text" style="display: block; font-size: 18px; font-weight: 300;">&nbsp;</div>
    <div style="background: rgb(0, 0, 0); opacity: 0.6; width: 100%; height: 100%; position: absolute; top: 0px;"></div>

Finally, replace .loader-text element's content on the fly on every navigation event and turn on the #resultloading div, note that it is initially hidden.

var showLoader = function (text) {

jQuery(document).ready(function () {
    jQuery(window).on("beforeunload ", function () {
        showLoader('Loading, please wait...');

This can be applied to any html based project with jQuery where you don't know which pages of your administration area will take too long to finish loading.

The gif image is 176x176px but you can use any transparent gif animation, please take into account that the image size is not important as it will be maxed to 150x150px.

Also, the function showLoader can be called on an element's click to perform an action that will further redirect the page, that is why it is provided ad an individual function. i hope this can also help anyone.

Making text background transparent but not text itself

box-shadow: inset 1px 2000px rgba(208, 208, 208, 0.54);

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

BY default password will be null, so you have to change password by doing below steps.

connect to mysql

root# mysql

Use mysql

mysql> update user set password=PASSWORD('root') where User='root'; Finally, reload the privileges:

mysql> flush privileges; mysql> quit

Python int to binary string?

you can do like that :


or :

f = str(bin(10))
c = []
c.append("".join(map(int, f[2:])))
print c

Change the bullet color of list

I would recommend you to use background-image instead of default list.

.listStyle {
    list-style: none;
    background: url(image_path.jpg) no-repeat left center;
    padding-left: 30px;
    width: 20px;
    height: 20px;

Or, if you don't want to use background-image as bullet, there is an option to do it with pseudo element:

    list-style: none;
    margin: 0;
    padding: 0;
.liststyle:before {
    content: "• ";
    color: red; /* or whatever color you prefer */
    font-size: 20px;/* or whatever the bullet size you prefer */

How to supply value to an annotation from a Constant java

I am thinking this may not be possible in Java because annotation and its parameters are resolved at compile time.

With Seam 2 you were able to resolve annotation parameters at runtime, with expression language inside double quotes.

In Seam 3, this feature is the module Seam Solder

How to mount the android img file under linux?

I have found a simple solution:


(with slight adjustments for better readability)

This is for all who want to unpack and modify the original system.img that you can flash using recovery. system.img (which you get from the google factory images for example) represents a sparse ext4 loop mounted file system. It is mounted into /system of your device. Note that this tutorial is for ext4 file system. You may have system image which is yaffs2, for example.

The way it is mounted on Galaxy Nexus:

/dev/block/platform/omap/omap_hsmmc.0/by-name/system /system ext4 ro,relatime,barrier=1,data=ordered 0 0


  • Linux box or virtual machine
  • simg2img and make_ext4fs binaries, which can be downloaded from the linux package android-tools-fsutils


Place your system.img and the 2 binaries in one directory, and make sure the binaries have exec permission.

Part 1 – mount the file-system

mkdir sys
./simg2img system.img sys.raw
sudo mount -t ext4 -o loop sys.raw sys/

Then you have your system partition mounted in ‘sys/’ and you can modify whatever you want in ‘sys/’. For example de-odex apks and framework jars.

Part 2 – create a new flashable system image

sudo ./make_ext4fs -s -l 512M -a system new.img sys/
sudo umount sys
rm -fr sys

Now you can simply type:

fastboot flash system new.img

TypeError: int() argument must be a string, a bytes-like object or a number, not 'list'

What the error is telling, is that you can't convert an entire list into an integer. You could get an index from the list and convert that into an integer:

x = ["0", "1", "2"] 
y = int(x[0]) #accessing the zeroth element

If you're trying to convert a whole list into an integer, you are going to have to convert the list into a string first:

x = ["0", "1", "2"]
y = ''.join(x) # converting list into string
z = int(y)

If your list elements are not strings, you'll have to convert them to strings before using str.join:

x = [0, 1, 2]
y = ''.join(map(str, x))
z = int(y)

Also, as stated above, make sure that you're not returning a nested list.

How to get response using cURL in PHP

The ultimate curl php function:

function getURL($url,$fields=null,$method=null,$file=null){
    // author   = Ighor Toth <[email protected]>
    // required:
    //      url     = include http or https 
    // optionals:
    //      fields  = must be array (e.g.: 'field1' => $field1, ...)
    //      method  = "GET", "POST"
    //      file    = if want to download a file, declare store location and file name (e.g.: /var/www/img.jpg, ...)
    // please crete 'cookies' dir to store local cookies if neeeded

    // do not modify below
    $useragent = 'Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko';
    $timeout= 240;
    $dir = dirname(__FILE__);
    $cookie_file    = $dir . '/cookies/' . md5($_SERVER['REMOTE_ADDR']) . '.txt';
    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);    
    curl_setopt($ch, CURLOPT_FAILONERROR, true);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_COOKIEFILE, $cookie_file);
    curl_setopt($ch, CURLOPT_COOKIEJAR, $cookie_file);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true );
    curl_setopt($ch, CURLOPT_ENCODING, "" );
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true );
    curl_setopt($ch, CURLOPT_AUTOREFERER, true );
    curl_setopt($ch, CURLOPT_MAXREDIRS, 10 );
    curl_setopt($ch, CURLOPT_USERAGENT, $useragent);
    curl_setopt($ch, CURLOPT_REFERER, '');
        if (!curl_setopt($ch, CURLOPT_FILE, $file)){ // Handle error
                die("curl setopt bit the dust: " . curl_error($ch));
        //curl_setopt($ch, CURLOPT_FILE, $file);
        $timeout= 3600;
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout );
    curl_setopt($ch, CURLOPT_TIMEOUT, $timeout );
        $postvars = http_build_query($fields); // build the urlencoded data
            // set the url, number of POST vars, POST data
            curl_setopt($ch, CURLOPT_POST, count($fields));
            curl_setopt($ch, CURLOPT_POSTFIELDS, $postvars);
            curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
            $url = $url.'?'.$postvars;
    curl_setopt($ch, CURLOPT_URL, $url);
    $content = curl_exec($ch);
    if (!$content){
        $error = curl_error($ch);
        $info = curl_getinfo($ch);
        die("cURL request failed, error = {$error}; info = " . print_r($info, true));
        echo 'error:' . curl_error($ch);
    } else {
        return $content;        

JavaScript check if variable exists (is defined/initialized)

You can also use !! before a variable to check if it's defined. E.g.

let dog = "woof";
let chineseCat; // Undefined.
console.log(!!dog && !!chineseCat ? "Both are defined" : "Both are NOT defined");

chineseCat= "mao"; // dog and chineseCat are now defined.
console.log(!!dog && !!chineseCat ? "Both are defined" : "Both are NOT defined");


Both are NOT defined
Both are defined

npx command not found

if you are using Linux system, use sudo command

sudo npm i -g npx

CSS: fixed position on x-axis but not y?

I realize this thread is mighty old but it helped me come up with a solution for my project.

In my case I had a header that I wanted to never be less than 1000px wide, header always on top, with content that could go unlimited right.

header{position:fixed; min-width:1024px;}
<header data-min-width="1024"></header>

    $(window).on('scroll resize', function () {
        var header = $('header');
        if ($(this).width() <'min-width')) {
            header.css('left', -$(this).scrollLeft());
        } else {
            header.css('left', '');

This also should handle when your browser is less than your headers min-width

Smooth scroll to specific div on click

You can use basic css to achieve smooth scroll

html {
  scroll-behavior: smooth;

How to use boolean datatype in C?

If you have a compiler that supports C99 you can

#include <stdbool.h>

Otherwise, you can define your own if you'd like. Depending on how you want to use it (and whether you want to be able to compile your code as C++), your implementation could be as simple as:

#define bool int
#define true 1
#define false 0

In my opinion, though, you may as well just use int and use zero to mean false and nonzero to mean true. That's how it's usually done in C.

What is AF_INET, and why do I need it?

You need arguments like AF_UNIX or AF_INET to specify which type of socket addressing you would be using to implement IPC socket communication. AF stands for Address Family.

As in BSD standard Socket (adopted in Python socket module) addresses are represented as follows:

  1. A single string is used for the AF_UNIX/AF_LOCAL address family. This option is used for IPC on local machines where no IP address is required.

  2. A pair (host, port) is used for the AF_INET address family, where host is a string representing either a hostname in Internet domain notation like '' or an IPv4 address like '', and port is an integer. Used to communicate between processes over the Internet.

AF_UNIX , AF_INET6 , AF_NETLINK , AF_TIPC , AF_CAN , AF_BLUETOOTH , AF_PACKET , AF_RDS are other option which could be used instead of AF_INET.

This thread about the differences between AF_INET and PF_INET might also be useful.

What is difference between Lightsail and EC2?

Lightsail VPSs are bundles of existing AWS products, offered through a significantly simplified interface. The difference is that Lightsail offers you a limited and fixed menu of options but with much greater ease of use. Other than the narrower scope of Lightsail in order to meet the requirements for simplicity and low cost, the underlying technology is the same.

The pre-defined bundles can be described:

% aws lightsail --region us-east-1 get-bundles
    "bundles": [
            "name": "Nano",
            "power": 300,
            "price": 5.0,
            "ramSizeInGb": 0.5,
            "diskSizeInGb": 20,
            "transferPerMonthInGb": 1000,
            "cpuCount": 1,
            "instanceType": "t2.nano",
            "isActive": true,
            "bundleId": "nano_1_0"

It's worth reading through the Amazon EC2 T2 Instances documentation, particularly the CPU Credits section which describes the base and burst performance characteristics of the underlying instances.

Importantly, since your Lightsail instances run in VPC, you still have access to the full spectrum of AWS services, e.g. S3, RDS, and so on, as you would from any EC2 instance.

Visual Studio : short cut Key : Duplicate Line

Here's a macro based on the one in the link posted by Wael, but improved in the following areas:

  • slightly shorter
  • slightly faster
  • comments :)
  • behaves for lines starting with "///"
  • can be undone with a single undo
Imports System
Imports EnvDTE
Imports EnvDTE80

Public Module Module1

    Sub DuplicateLine()
        Dim sel As TextSelection = DTE.ActiveDocument.Selection
        sel.StartOfLine(0) '' move to start
        sel.EndOfLine(True) '' select to end
        Dim line As String = sel.Text
        sel.EndOfLine(False) '' move to end
        sel.Insert(ControlChars.NewLine + line, vsInsertFlags.vsInsertFlagsCollapseToEnd)
    End Sub

End Module

Method with a bool return

I'm sure neither of these options were available in C# when you asked the question but nowadays you can do it like the following:

// Return with ternary conditional operator.
private bool CheckAll()
    return (your_condition) ? true : false;

// Alternatively as an expression bodied method.
private bool CheckAll() => (your_condition) ? true : false;

In javascript, how do you search an array for a substring match

If you're able to use Underscore.js in your project, the _.filter() array function makes this a snap:

// find all strings in array containing 'thi'
var matches = _.filter(
    [ 'item 1', 'thing', 'id-3-text', 'class' ],
    function( s ) { return s.indexOf( 'thi' ) !== -1; }

The iterator function can do whatever you want as long as it returns true for matches. Works great.

Update 2017-12-03:
This is a pretty outdated answer now. Maybe not the most performant option in a large batch, but it can be written a lot more tersely and use native ES6 Array/String methods like .filter() and .includes() now:

// find all strings in array containing 'thi'
const items = ['item 1', 'thing', 'id-3-text', 'class'];
const matches = items.filter(s => s.includes('thi'));

Note: There's no <= IE11 support for String.prototype.includes() (Edge works, mind you), but you're fine with a polyfill, or just fall back to indexOf().

Javascript Thousand Separator / string format

Updated using look-behind support in line with ECMAScript2018 changes.
For backwards compatibility, scroll further down to see the original solution.

A regular expression may be used - notably useful in dealing with big numbers stored as strings.

const format = num => _x000D_
    String(num).replace(/(?<!\..*)(\d)(?=(?:\d{3})+(?:\.|$))/g, '$1,')_x000D_
    format(100),                           // "100"_x000D_
    format(1000),                          // "1,000"_x000D_
    format(1e10),                          // "10,000,000,000"  _x000D_
    format(1000.001001),                   // "1,000.001001"_x000D_
    format('100000000000000.001001001001') // "100,000,000,000,000.001001001001_x000D_
    .forEach(n => console.log(n))

» Verbose regex explanation ( flow diagram

This original answer may not be required but can be used for backwards compatibility.

Attempting to handle this with a single regular expression (without callback) my current ability fails me for lack of a negative look-behind in Javascript... never the less here's another concise alternative that works in most general cases - accounting for any decimal point by ignoring matches where the index of the match appears after the index of a period.

const format = num => {_x000D_
    const n = String(num),_x000D_
          p = n.indexOf('.')_x000D_
    return n.replace(_x000D_
        (m, i) => p < 0 || i < p ? `${m},` : m_x000D_
    format(100),                           // "100"_x000D_
    format(1000),                          // "1,000"_x000D_
    format(1e10),                          // "10,000,000,000"  _x000D_
    format(1000.001001),                   // "1,000.001001"_x000D_
    format('100000000000000.001001001001') // "100,000,000,000,000.001001001001_x000D_
    .forEach(n => console.log(n))

» Verbose regex explanation (

flow diagram

How to convert NSData to byte array in iPhone?

Here's what I believe is the Swift equivalent:

if let data = NSData(contentsOfFile: filePath) {
   let length = data.length
   let byteData = malloc(length)
   memcmp(byteData, data.bytes, length)

JSP tricks to make templating easier?

Use tiles. It saved my life.

But if you can't, there's the include tag, making it similar to php.

The body tag might not actually do what you need it to, unless you have super simple content. The body tag is used to define the body of a specified element. Take a look at this example:

<jsp:element name="${content.headerName}"   
   <jsp:attribute name="lang">${content.lang}</jsp:attribute>   

You specify the element name, any attributes that element might have ("lang" in this case), and then the text that goes in it--the body. So if

  • content.headerName = h1,
  • content.lang = fr, and
  • content.body = Heading in French

Then the output would be

<h1 lang="fr">Heading in French</h1>

Add Insecure Registry to Docker

Creating /etc/docker/daemon.json file and adding the below content and then doing a docker restart on CentOS 7 resolved the issue.

    "insecure-registries" : [ "" ]

How to generate and manually insert a uniqueidentifier in sql server?

Kindly check Column ApplicationId datatype in Table aspnet_Users , ApplicationId column datatype should be uniqueidentifier .

*Your parameter order is passed wrongly , Parameter @id should be passed as first argument, but in your script it is placed in second argument..*

So error is raised..

Please refere sample script:

DECLARE @id uniqueidentifier
SET @id = NEWID()
Create Table #temp1(AppId uniqueidentifier)

insert into #temp1 values(@id)

Select * from #temp1

Drop Table #temp1

get all characters to right of last dash

string tail = test.Substring(test.LastIndexOf('-') + 1);

How to check cordova android version of a cordova/phonegap project?

After upgrading the Application. I observed different Cordova versions.

  1. Apache Cordova Cli version which is 6.0.0.
  2. Cordova Android version which is 5.1.0.
  3. Cordova IOS version which is 4.1.1.
  4. Docs version is which is 6.0.0, shown on the Cordova Docs website.

Now i am confused, On which version basis, Google Dev Console is giving warning?

Please migrate your app(s) to Apache Cordova v.4.1.1 or higher as soon as possible and increment the version number of the upgraded APK. Beginning May 9, 2016, Google Play will block publishing of any new apps or updates that use pre-4.1.1 versions of Apache Cordova.

The vulnerabilities were addressed in Apache Cordova 4.1.1. If you’re using a 3rd party library that bundles Apache Cordova, you’ll need to upgrade it to a version that bundles Apache Cordova 4.1.1 or later.

And before upgrading. Our Application versions were these.

  1. Apache Cordova Cli version which is 5.4.1.
  2. Cordova Android version which is 4.1.1.
  3. Cordova IOS version which is 3.9.1.
  4. Docs version is which is 5.4.1, shown on the Cordova Docs website.

Linq to Entities - SQL "IN" clause

Real example:

var trackList = Model.TrackingHistory.GroupBy(x => x.ShipmentStatusId).Select(x => x.Last()).Reverse();
List<int> done_step1 = new List<int>() {2,3,4,5,6,7,8,9,10,11,14,18,21,22,23,24,25,26 };
bool isExists = trackList.Where(x => done_step1.Contains(x.ShipmentStatusId.Value)).FirstOrDefault() != null;

Convert List(of object) to List(of string)

Not possible without iterating to build a new list. You can wrap the list in a container that implements IList.

You can use LINQ to get a lazy evaluated version of IEnumerable<string> from an object list like this:

var stringList = myList.OfType<string>();

How to create a GUID/UUID using iOS

Here is the simple code I am using, compliant with ARC.

+(NSString *)getUUID
    CFUUIDRef newUniqueId = CFUUIDCreate(kCFAllocatorDefault);
    NSString * uuidString = (__bridge_transfer NSString*)CFUUIDCreateString(kCFAllocatorDefault, newUniqueId);

    return uuidString;

Centering the image in Bootstrap

Use This as the solution

This worked for me perfectly..

<div align="center">
   <img src="">

How can getContentResolver() be called in Android?

You can use like this:


with the proper context.

REST API Best practices: Where to put parameters?

It's a very interesting question.

You can use both of them, there's not any strict rule about this subject, but using URI path variables has some advantages:

  • Cache: Most of the web cache services on the internet don't cache GET request when they contains query parameters. They do that because there are a lot of RPC systems using GET requests to change data in the server (fail!! Get must be a safe method)

But if you use path variables, all of this services can cache your GET requests.

  • Hierarchy: The path variables can represent hierarchy: /City/Street/Place

It gives the user more information about the structure of the data.

But if your data doesn't have any hierarchy relation you can still use Path variables, using comma or semi-colon:


As a rule, use comma when the ordering of the parameters matter, use semi-colon when the ordering doesn't matter:


Apart of those reasons, there are some cases when it's very common to use query string variables:

  • When you need the browser to automatically put HTML form variables into the URI
  • When you are dealing with algorithm. For example the google engine use query strings:


To sum up, there's not any strong reason to use one of this methods but whenever you can, use URI variables.

How do I make a placeholder for a 'select' box?

Something like this:


<select id="choice">
    <option value="0" selected="selected">Choose...</option>
    <option value="1">Something</option>
    <option value="2">Something else</option>
    <option value="3">Another choice</option>


#choice option { color: black; }
.empty { color: gray; }


$("#choice").change(function () {
    if($(this).val() == "0") $(this).addClass("empty");
    else $(this).removeClass("empty")


Working example:

C++ templates that accept only certain types

class Base
    struct FooSecurity{};

template<class Type>
class Foo
    typename Type::FooSecurity If_You_Are_Reading_This_You_Tried_To_Create_An_Instance_Of_Foo_For_An_Invalid_Type;

Make sure derived classes inherit the FooSecurity structure and the compiler will get upset in all the right places.

What is the benefit of zerofill in MySQL?

One example in order to understand, where the usage of ZEROFILL might be interesting:

In Germany, we have 5 digit zipcodes. However, those Codes may start with a Zero, so 80337 is a valid zipcode for munic, 01067 is a zipcode of Berlin.

As you see, any German citizen expects the zipcodes to be displayed as a 5 digit code, so 1067 looks strange.

In order to store those data, you could use a VARCHAR(5) or INT(5) ZEROFILL whereas the zerofilled integer has two big advantages:

  1. Lot lesser storage space on hard disk
  2. If you insert 1067, you still get 01067 back

Maybe this example helps understanding the use of ZEROFILL.

Excel function to make SQL-like queries on worksheet data?

If you can save the workbook then you have the option to use ADO and Jet/ACE to treat the workbook as a database, and execute SQL against the sheet.

The MSDN information on how to hit Excel using ADO can be found here.

how to make password textbox value visible when hover an icon

Its simple javascript. Done using toggling the type attribute of the input. Check this

Laravel: How to Get Current Route Name? (v5 ... v7)

Accessing The Current Route

Get current route name in Blade templates

{{ Route::currentRouteName() }}

for more info

Why use pip over easy_install?

UPDATE: setuptools has absorbed distribute as opposed to the other way around, as some thought. setuptools is up-to-date with the latest distutils changes and the wheel format. Hence, easy_install and pip are more or less on equal footing now.


Creating a data frame from two vectors using cbind

Vectors and matrices can only be of a single type and cbind and rbind on vectors will give matrices. In these cases, the numeric values will be promoted to character values since that type will hold all the values.

(Note that in your rbind example, the promotion happens within the c call:

> c(10, "[]", "[[1,2]]")
[1] "10"      "[]"      "[[1,2]]"

If you want a rectangular structure where the columns can be different types, you want a data.frame. Any of the following should get you what you want:

> x = data.frame(v1=c(10, 20), v2=c("[]", "[]"), v3=c("[[1,2]]","[[1,3]]"))
> x
  v1 v2      v3
1 10 [] [[1,2]]
2 20 [] [[1,3]]
> str(x)
'data.frame':   2 obs. of  3 variables:
 $ v1: num  10 20
 $ v2: Factor w/ 1 level "[]": 1 1
 $ v3: Factor w/ 2 levels "[[1,2]]","[[1,3]]": 1 2

or (using specifically the data.frame version of cbind)

> x =, 20), c("[]", "[]"), c("[[1,2]]","[[1,3]]"))
> x
  c(10, 20) c("[]", "[]") c("[[1,2]]", "[[1,3]]")
1        10            []                 [[1,2]]
2        20            []                 [[1,3]]
> str(x)
'data.frame':   2 obs. of  3 variables:
 $ c(10, 20)              : num  10 20
 $ c("[]", "[]")          : Factor w/ 1 level "[]": 1 1
 $ c("[[1,2]]", "[[1,3]]"): Factor w/ 2 levels "[[1,2]]","[[1,3]]": 1 2

or (using cbind, but making the first a data.frame so that it combines as data.frames do):

> x = cbind(data.frame(c(10, 20)), c("[]", "[]"), c("[[1,2]]","[[1,3]]"))
> x
  c.10..20. c("[]", "[]") c("[[1,2]]", "[[1,3]]")
1        10            []                 [[1,2]]
2        20            []                 [[1,3]]
> str(x)
'data.frame':   2 obs. of  3 variables:
 $ c.10..20.              : num  10 20
 $ c("[]", "[]")          : Factor w/ 1 level "[]": 1 1
 $ c("[[1,2]]", "[[1,3]]"): Factor w/ 2 levels "[[1,2]]","[[1,3]]": 1 2

What's the simplest way to list conflicted files in Git?

Utility git wizard counts separately unresolved conflicted changes (collisions) and unmerged files. Conflicts must be resolved manually or with mergetool. Resolved unmerged changes can me added and committed usually with git rebase --continue.

val() vs. text() for textarea

The best way to set/get the value of a textarea is the .val(), .value method.

.text() internally uses the .textContent (or .innerText for IE) method to get the contents of a <textarea>. The following test cases illustrate how text() and .val() relate to each other:

var t = '<textarea>';
console.log($(t).text('test').val());             // Prints test
console.log($(t).val('too').text('test').val());  // Prints too
console.log($(t).val('too').text());              // Prints nothing
console.log($(t).text('test').val('too').val());  // Prints too

console.log($(t).text('test').val('too').text()); // Prints test

The value property, used by .val() always shows the current visible value, whereas text()'s return value can be wrong.

Size of character ('a') in C/C++

In C language, character literal is not a char type. C considers character literal as integer. So, there is no difference between sizeof('a') and sizeof(1).

So, the sizeof character literal is equal to sizeof integer in C.

In C++ language, character literal is type of char. The cppreference say's:

1) narrow character literal or ordinary character literal, e.g. 'a' or '\n' or '\13'. Such literal has type char and the value equal to the representation of c-char in the execution character set. If c-char is not representable as a single byte in the execution character set, the literal has type int and implementation-defined value.

So, in C++ character literal is a type of char. so, size of character literal in C++ is one byte.

Alos, In your programs, you have used wrong format specifier for sizeof operator.

C11 § (P9) :

If a conversion specification is invalid, the behavior is undefined.275) If any argument is not the correct type for the corresponding conversion specification, the behavior is undefined.

So, you should use %zu format specifier instead of %d, otherwise it is undefined behaviour in C.

How to set a cron job to run at a exact time?

My use case is that I'm on a metered account. Data transfer is limited on weekdays, Mon - Fri, from 6am - 6pm. I am using bandwidth limiting, but somehow, data still slips through, about 1GB per day!

I strongly suspected it's sickrage or sickbeard, doing a high amount of searches. My download machine is called "download." The following was my solution, using the above,for starting, and stopping the download VM, using KVM:

# Stop download Mon-Fri, 6am
0 6 * * 1,2,3,4,5 root          virsh shutdown download
# Start download Mon-Fri, 6pm
0 18 * * 1,2,3,4,5 root         virsh start download

I think this is correct, and hope it helps someone else too.

How to change the opacity (alpha, transparency) of an element in a canvas element after it has been drawn?

Edit: The answer marked as "correct" is not correct.

It's easy to do. Try this code, swapping out "ie.jpg" with whatever picture you have handy:

            var canvas;
            var context;
            var ga = 0.0;
            var timerId = 0;
            function init()
                canvas = document.getElementById("myCanvas");
                context = canvas.getContext("2d");
                timerId = setInterval("fadeIn()", 100);
            function fadeIn()
                context.clearRect(0,0, canvas.width,canvas.height);
                context.globalAlpha = ga;
                var ie = new Image();
                ie.onload = function()
                    context.drawImage(ie, 0, 0, 100, 100);
                ie.src = "ie.jpg";
                ga = ga + 0.1;
                if (ga > 1.0)
                    goingUp = false;
    <body onload="init()">
        <canvas height="200" width="300" id="myCanvas"></canvas>

The key is the globalAlpha property.

Tested with IE 9, FF 5, Safari 5, and Chrome 12 on Win7.

How to upload (FTP) files to server in a bash script?

The ftp command isn't designed for scripts, so controlling it is awkward, and getting its exit status is even more awkward.

Curl is made to be scriptable, and also has the merit that you can easily switch to other protocols later by just modifying the URL. If you put your FTP credentials in your .netrc, you can simply do:

# Download file
curl --netrc --remote-name
# Upload file
curl --netrc --upload-file file.bin

If you must, you can specify username and password directly on the command line using --user username:password instead of --netrc.

Pretty-Printing JSON with PHP

This function will take JSON string and indent it very readable. It also should be convergent,

prettyPrint( $json ) === prettyPrint( prettyPrint( $json ) )




    "key1": [
    "key2": "value"


function prettyPrint( $json )
    $result = '';
    $level = 0;
    $in_quotes = false;
    $in_escape = false;
    $ends_line_level = NULL;
    $json_length = strlen( $json );

    for( $i = 0; $i < $json_length; $i++ ) {
        $char = $json[$i];
        $new_line_level = NULL;
        $post = "";
        if( $ends_line_level !== NULL ) {
            $new_line_level = $ends_line_level;
            $ends_line_level = NULL;
        if ( $in_escape ) {
            $in_escape = false;
        } else if( $char === '"' ) {
            $in_quotes = !$in_quotes;
        } else if( ! $in_quotes ) {
            switch( $char ) {
                case '}': case ']':
                    $ends_line_level = NULL;
                    $new_line_level = $level;

                case '{': case '[':
                case ',':
                    $ends_line_level = $level;

                case ':':
                    $post = " ";

                case " ": case "\t": case "\n": case "\r":
                    $char = "";
                    $ends_line_level = $new_line_level;
                    $new_line_level = NULL;
        } else if ( $char === '\\' ) {
            $in_escape = true;
        if( $new_line_level !== NULL ) {
            $result .= "\n".str_repeat( "\t", $new_line_level );
        $result .= $char.$post;

    return $result;

What is polymorphism, what is it for, and how is it used?

Polymorphism is an ability of object which can be taken in many forms. For example in human class a man can act in many forms when we talk about relationships. EX: A man is a father to his son and he is husband to his wife and he is teacher to his students.

Can't bind to 'ngIf' since it isn't a known property of 'div'

Just for anyone who still has an issue, I also had an issue where I typed ngif rather than ngIf (notice the capital 'I').

Remove duplicated rows using dplyr

If you want to find the rows that are duplicated you can use find_duplicates from hablar:


df <- tibble(a = c(1, 2, 2, 4),
             b = c(5, 2, 2, 8))

df %>% find_duplicates()

Ant build failed: "Target "build..xml" does not exist"

Looks like you called it 'ant build..xml'. ant automatically choose a file build.xml in the current directory, so it is enough to call 'ant' (if a default-target is defined) or 'ant target' (the target named target will be called).

With the call 'ant -p' you get a list of targets defined in your build.xml.

Edit: In the comment is shown the call 'ant -verbose build.xml'. To be correct, this has to be called as 'ant -verbose'. The file build.xml in the current directory will be used automatically. If it is needed to explicitly specify the buildfile (because it's name isn't build.xml for example), you have to specify the buildfile with the '-f'-option: 'ant -verbose -f build.xml'. I hope this helps.

Can not deserialize instance of java.util.ArrayList out of VALUE_STRING

from Jackson 2.7.x+ there is a way to annotate the member variable itself:

 @JsonFormat(with = JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY)
 private List<String> newsletters;

More info here: Jackson @JsonFormat

See changes to a specific file using git

Or if you prefer to use your own gui tool:

git difftool ./filepath

You can set your gui tool guided by this post: How do I view 'git diff' output with a visual diff program?

Can't get Gulp to run: cannot find module 'gulp-util'

Any answer didn't help in my case. What eventually helped was removing bower and gulp (I use both of them in my project):

npm remove -g bower
npm remove -g gulp

After that I installed them again:

npm install -g bower
npm install -g gulp

Now it works just fine.

Linking to a specific part of a web page

In case the target page is on the same domain (i.e. shares the same origin with your page) and you don't mind creation of new tabs (1), you can (ab)use some JavaScript:

<a href="javascript:void('./target.html').onload=function(){this.document.querySelector('p:nth-child(10)').scrollIntoView()})">see tenth paragraph on another page</a>


var w ='some URL of the same origin');
w.onload = function(){
  // do whatever you want with `this.document`, like

Working example of such 'exploit' you can try right now could be:


If you enter this into location bar (mind that Chrome removes javascript: prefix when pasted from clipboard) or make it a href value of any link on this page (using Developer Tools) and click it, you will get another (duplicate) SO question page scrolled to the footer and footer painted red. (Delay added as a workaround for ajax-loaded content pushing footer down after load.)


  • Tested in current Chrome and Firefox, generally should work since it is based on defined standard behaviour.
  • Cannot be illustrated in interactive snippet here at SO, because they are isolated from the page origin-wise.
  • MDN:
  • (1),'_self') seems to be breaking the load event; basically makes the behave like a normal a href="" click navigation; haven't researched more yet.

How can I check if PostgreSQL is installed or not via Linux script?

If you are running Debian Linux (or derivative) and if you have a postive return with > which psql, then simply type psql -V (capital "V") and you will get a return like: psql (PostgreSQL) 9.4.8

How do I trim leading/trailing whitespace in a standard way?

As the other answers don't seem to mutate the string pointer directly, but rather rely on the return value, I thought I would provide this method which additionally does not use any libraries and so is appropriate for operating system style programming:

// only used for printf in main
#include <stdio.h>

// note the char ** means we can modify the address
char *trimws(char **strp) { 
  char *str;
  // go to the end of the string
  for (str = *strp; *str; str++) 
  // back up one from the null terminator
  // set trailing ws to null
  for (; *str == ' '; str--) 
    *str = 0;
  // increment past leading ws
  for (str = *strp; *str == ' '; str++) 
  // set new begin address of string
  *strp = str; 

int main(void) {
  char buf[256] = "   whitespace    ";
  // pointer must be modifiable lvalue so we make bufp
  char **bufp = &buf;
  // pass in the address
  // prints : XXXwhitespaceXXX
  printf("XXX%sXXX\n", bufp); 
  return 0;

Pure CSS to make font-size responsive based on dynamic amount of characters

Create a lookup table that computes font-size based on the length of the string inside your <div>.

const fontSizeLookupTable = () => {
  // lookup table looks like: [ '72px', ..., '32px', ..., '16px', ..., ]
  let a = [];
  // adjust this based on how many characters you expect in your <div>
  a.length = 32;
  // adjust the following ranges empirically
  a.fill( '72px' ,     );
  a.fill( '32px' , 4 , );
  a.fill( '16px' , 8 , );
  // add more ranges as necessary
  return a;

const computeFontSize = stringLength => {
  const table = fontSizeLookupTable();
  return stringLength < table.length ? table[stringLength] : '16px';

Adjust and tune all parameters by empirical test.

How to write DataFrame to postgres table?

For Python 2.7 and Pandas 0.24.2 and using Psycopg2

Psycopg2 Connection Module

def dbConnect (db_parm, username_parm, host_parm, pw_parm):
    # Parse in connection information
    credentials = {'host': host_parm, 'database': db_parm, 'user': username_parm, 'password': pw_parm}
    conn = psycopg2.connect(**credentials)
    conn.autocommit = True  # auto-commit each entry to the database
    conn.cursor_factory = RealDictCursor
    cur = conn.cursor()
    print ("Connected Successfully to DB: " + str(db_parm) + "@" + str(host_parm))
    return conn, cur

Connect to the database

conn, cur = dbConnect(databaseName, dbUser, dbHost, dbPwd)

Assuming dataframe to be present already as df

output = io.BytesIO() # For Python3 use StringIO
df.to_csv(output, sep='\t', header=True, index=False) # Required for rewinding the String object
copy_query = "COPY mem_info FROM STDOUT csv DELIMITER '\t' NULL ''  ESCAPE '\\' HEADER "  # Replace your table name in place of mem_info
cur.copy_expert(copy_query, output)

SharePoint 2013 get current user using JavaScript

Here is the code that worked for me:

<script src="/SiteAssets/jquery.SPServices-2013.02a.js" type="text/javascript"></script>
<script src="/SiteAssets/jquery.js" type="text/javascript"></script>

<script type="text/javascript">
  var userid= _spPageContextInfo.userId;
  var requestUri = _spPageContextInfo.webAbsoluteUrl + "/_api/web/getuserbyid(" + userid + ")";
  var requestHeaders = { "accept" : "application/json;odata=verbose" };
    url : requestUri,
    contentType : "application/json;odata=verbose",
    headers : requestHeaders,
    success : onSuccess,
    error : onError

  function onSuccess(data, request){
    var loginName = data.d.Title;

  function onError(error) {

jQuery replace one class with another

In jquery to replace a class with another you can use jqueryUI SwitchClass option

 $("#YourID").switchClass("old-class-here", "new-class-here"); 

What does this error mean: "error: expected specifier-qualifier-list before 'type_name'"?

You have to name your struct like that:

typedef struct car_t {



} car_t;

Accept function as parameter in PHP

Simple example using a class :

class test {

    public function works($other_parameter, $function_as_parameter)

        return $function_as_parameter($other_parameter) ;



$obj = new test() ;

echo $obj->works('working well',function($other_parameter){

    return $other_parameter;


How to convert .pfx file to keystore with private key?

I found this page which tells you how to import a PFX to JKS (Java Key Store):

keytool -importkeystore -srckeystore PFX_P12_FILE_NAME -srcstoretype pkcs12 -srcstorepass PFX_P12_FILE -srcalias SOURCE_ALIAS -destkeystore KEYSTORE_FILE -deststoretype jks -deststorepass PASSWORD -destalias ALIAS_NAME

When to use the JavaScript MIME type application/javascript instead of text/javascript?

application because .js-Files aren't something a user wants to read but something that should get executed.

What do 1.#INF00, -1.#IND00 and -1.#IND mean?

From IEEE floating-point exceptions in C++ :

This page will answer the following questions.

  • My program just printed out 1.#IND or 1.#INF (on Windows) or nan or inf (on Linux). What happened?
  • How can I tell if a number is really a number and not a NaN or an infinity?
  • How can I find out more details at runtime about kinds of NaNs and infinities?
  • Do you have any sample code to show how this works?
  • Where can I learn more?

These questions have to do with floating point exceptions. If you get some strange non-numeric output where you're expecting a number, you've either exceeded the finite limits of floating point arithmetic or you've asked for some result that is undefined. To keep things simple, I'll stick to working with the double floating point type. Similar remarks hold for float types.

Debugging 1.#IND, 1.#INF, nan, and inf

If your operation would generate a larger positive number than could be stored in a double, the operation will return 1.#INF on Windows or inf on Linux. Similarly your code will return -1.#INF or -inf if the result would be a negative number too large to store in a double. Dividing a positive number by zero produces a positive infinity and dividing a negative number by zero produces a negative infinity. Example code at the end of this page will demonstrate some operations that produce infinities.

Some operations don't make mathematical sense, such as taking the square root of a negative number. (Yes, this operation makes sense in the context of complex numbers, but a double represents a real number and so there is no double to represent the result.) The same is true for logarithms of negative numbers. Both sqrt(-1.0) and log(-1.0) would return a NaN, the generic term for a "number" that is "not a number". Windows displays a NaN as -1.#IND ("IND" for "indeterminate") while Linux displays nan. Other operations that would return a NaN include 0/0, 0*8, and 8/8. See the sample code below for examples.

In short, if you get 1.#INF or inf, look for overflow or division by zero. If you get 1.#IND or nan, look for illegal operations. Maybe you simply have a bug. If it's more subtle and you have something that is difficult to compute, see Avoiding Overflow, Underflow, and Loss of Precision. That article gives tricks for computing results that have intermediate steps overflow if computed directly.

Casting int to bool in C/C++

The following cites the C11 standard (final draft). When any scalar value is converted to _Bool, the result is 0 if the value compares equal to 0; otherwise, the result is 1.

bool (mapped by stdbool.h to the internal name _Bool for C) itself is an unsigned integer type:

... The type _Bool and the unsigned integer types that correspond to the standard signed integer types are the standard unsigned integer types.

According to 6.2.5p2:

An object declared as type _Bool is large enough to store the values 0 and 1.

AFAIK these definitions are semantically identical to C++ - with the minor difference of the built-in(!) names. bool for C++ and _Bool for C.

Note that C does not use the term rvalues as C++ does. However, in C pointers are scalars, so assigning a pointer to a _Bool behaves as in C++.

How to remove specific session in

There are many ways to nullify session in ASP.NET. Session in essence is a cookie, set on client's browser and in ASP.NET, its name is usually ASP.NET_SessionId. So, theoretically if you delete that cookie (which in terms of browser means that you set its expiration date to some date in past, because cookies can't be deleted by developers), then you loose the session in server. Another way as you said is to use Session.Clear() method. But the best way is to set another irrelevant object (usually null value) in the session in correspondance to a key. For example, to nullify Session["FirstName"], simply set it to Session["FirstName"] = null.

org.xml.sax.SAXParseException: Premature end of file for *VALID* XML

It is a problem with Java InputStream. When the stream is read once the file offset position counter is moved to the end of file. On the subsequent read by using the same stream you'll get this error. So you have to close and reopen the stream again or call inputStream.reset() to reset the offset counter to its initial position.

python pandas extract year from datetime: df['year'] = df['date'].year is not working

What worked for me was upgrading pandas to latest version:

From Command Line do:

conda update pandas

Unable to run Java GUI programs with Ubuntu

In my case


was set (indirectly by a Maven configuration). I had to actively use


to override this.

How to save a Python interactive session?

If you use bpython, all your command history is by default saved to ~/.pythonhist.

To save the commands for later reusage you can copy them to a python script file:

$ cp ~/.pythonhist

Then edit that file to clean it up and put it under Python path (global or virtual environment's site-packages, current directory, mentioning in *.pth, or some other way).

To include the commands into your shell, just import them from the saved file:

>>> from mycommands import *

Adding Table rows Dynamically in Android

You shouldn't be using an item defined in the Layout XML in order to create more instances of it. You should either create it in a separate XML and inflate it or create the TableRow programmaticaly. If creating them programmaticaly, should be something like this:

    public void init(){
    TableLayout ll = (TableLayout) findViewById(;

    for (int i = 0; i <2; i++) {

        TableRow row= new TableRow(this);
        TableRow.LayoutParams lp = new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT);
        checkBox = new CheckBox(this);
        tv = new TextView(this);
        addBtn = new ImageButton(this);
        minusBtn = new ImageButton(this);
        qty = new TextView(this);

Apache HttpClient 4.0.3 - how do I set cookie with sessionID for POST request?

I did it by passing the cookie through the HttpContext:

HttpContext localContext = new BasicHttpContext();

localContext.setAttribute(ClientContext.COOKIE_STORE, cookieStore);

response = client.execute(httppost, localContext);

What's the difference between HTML 'hidden' and 'aria-hidden' attributes?

setting aria-hidden to false and toggling it on worked for me.


<span aria-hidden="true">aria text</span>

$(span).attr('aria-hidden', 'false');

and when hiding back

$(span).attr('aria-hidden', 'true');

BOOLEAN or TINYINT confusion

The Newest MySQL Versions have the new BIT data type in which you can specify the number of bits in the field, for example BIT(1) to use as Boolean type, because it can be only 0 or 1.

ImportError: No module named PyQt4.QtCore

Try this command to solve your problem.

sudo apt install build-essential python3-dev libqt4-dev

This works for me in python3.

Click a button with XPath containing partial id and title in Selenium IDE

Now that you have provided your HTML sample, we're able to see that your XPath is slightly wrong. While it's valid XPath, it's logically wrong.

You've got:

//*[contains(@id, 'ctl00_btnAircraftMapCell')]//*[contains(@title, 'Select Seat')]

Which translates into:

Get me all the elements that have an ID that contains ctl00_btnAircraftMapCell. Out of these elements, get any child elements that have a title that contains Select Seat.

What you actually want is:

//a[contains(@id, 'ctl00_btnAircraftMapCell') and contains(@title, 'Select Seat')]

Which translates into:

Get me all the anchor elements that have both: an id that contains ctl00_btnAircraftMapCell and a title that contains Select Seat.

Change One Cell's Data in mysql

try this.

UPDATE `database_name`.`table_name` SET `column_name`='value' WHERE `id`='1';

Detect if a NumPy array contains at least one non-numeric value?

This should be faster than iterating and will work regardless of shape.


Edit: 30x faster:

import timeit
s = 'import numpy;a = numpy.arange(10000.).reshape((100,100));a[10,10]=numpy.nan'
ms = [
    'any(numpy.isnan(x) for x in a.flatten())']
for m in ms:
    print "  %.2f s" % timeit.Timer(m, s).timeit(1000), m


  0.11 s numpy.isnan(a).any()
  3.75 s any(numpy.isnan(x) for x in a.flatten())

Bonus: it works fine for non-array NumPy types:

>>> a = numpy.float64(42.)
>>> numpy.isnan(a).any()
>>> a = numpy.float64(numpy.nan)
>>> numpy.isnan(a).any()

How do I use Node.js Crypto to create a HMAC-SHA1 hash?

Documentation for crypto:

const crypto = require('crypto')

const text = 'I love cupcakes'
const key = 'abcdeg'

crypto.createHmac('sha1', key)

.htaccess not working on localhost with XAMPP

I've setup xampp for my localhost as well, I've not done anything with the files created by xampp during or after setup.

But in the '.htaccess' file, make sure you've set it to something like this. Works for me, and this should not make any difference for you.

RewriteEngine On
RewriteRule ^filename/?$ filename.html

Change .html to whatever format you're using.

Make sure your install is clean, and just make the .htaccess file. Also remember to put one .htaccess file for each directory (don't really know if you can use ONE file for all folders, but to be safe, just do this and it will always work.

How to reject in async/await syntax?

This is not an answer over @T.J. Crowder's one. Just an comment responding to the comment "And actually, if the exception is going to be converted to a rejection, I'm not sure whether I am actually bothered if it's an Error. My reasons for throwing only Error probably don't apply."

if your code is using async/await, then it is still a good practice to reject with an Error instead of 400:

try {
  await foo('a');
catch (e) {
  // you would still want `e` to be an `Error` instead of `400`

How to append multiple values to a list in Python

If you take a look at the official docs, you'll see right below append, extend. That's what your looking for.

There's also itertools.chain if you are more interested in efficient iteration than ending up with a fully populated data structure.

Java "lambda expressions not supported at this language level"

For me none of the solutions provided worked.

This should be your last resort: -> Open .iml file of your project change the LANGUAGE_LEVEL to JDK_1_8 or whatever version you wish. -> If this didn't help, you should grep "JDK" in your project root directory and find the file which contains version setting and set it to your preferred version.

Visual Studio Code Automatic Imports

There is a Visual Studio Code issue you can track and thumbs up for this feature. There was also a User Voice issue, but I believe they moved voting to GitHub issues.

It seems they want auto import functionality in TypeScript, so it can be reused. TypeScript auto import issue to track and thumbs up here.

Android check null or empty string in Android

This worked for me

EditText   etname = (EditText) findViewById(;
 if(etname.length() == 0){
                    etname.setError("Required field");

or Use this for strings

String DEP_DATE;
if (DEP_DATE.equals("") || DEP_DATE.length() == 0 || DEP_DATE.isEmpty() || DEP_DATE == null){

How can I know if Object is String type object?

javamonkey79 is right. But don't forget what you might want to do (e.g. try something else or notify someone) if object is not an instance of String.

String myString;
if (object instanceof String) {
  myString = (String) object;
} else {
  // do something else     

BTW: If you use ClassCastException instead of Exception in your code above, you can be sure that you will catch the exception caused by casting object to String. And not any other exceptions caused by other code (e.g. NullPointerExceptions).

Sending a file over TCP sockets in Python

Client need to notify that it finished sending, using socket.shutdown (not socket.close which close both reading/writing part of the socket):

print "Done Sending"
print s.recv(1024)


Client sends Hello server! to the server; which is written to the file in the server side.

s.send("Hello server!")

Remove above line to avoid it.

time.sleep -- sleeps thread or process?

The thread will block, but the process is still alive.

In a single threaded application, this means everything is blocked while you sleep. In a multithreaded application, only the thread you explicitly 'sleep' will block and the other threads still run within the process.

How to set a default row for a query that returns no rows?

This snippet uses Common Table Expressions to reduce redundant code and to improve readability. It is a variation of John Baughman's answer.

The syntax is for SQL Server.

WITH products AS (
            SELECT prod_name,
              FROM Products_Table
             WHERE prod_name LIKE '%foo%'
     defaults AS (
            SELECT '-' AS prod_name,
                   0   AS price

SELECT * FROM products
SELECT * FROM defaults

ReactJS: Maximum update depth exceeded error

In this case , this code

{<td><span onClick={this.toggle()}>Details</span></td>}

causes toggle function to call immediately and re render it again and again thus making infinite calls.

so passing only the reference to that toggle method will solve the problem.

so ,

{<td><span onClick={this.toggle}>Details</span></td>}

will be the solution code.

If you want to use the () , you should use an arrow function like this

{<td><span onClick={()=> this.toggle()}>Details</span></td>}

In case you want to pass parameters you should choose the last option and you can pass parameters like this

{<td><span onClick={(arg)=>this.toggle(arg)}>Details</span></td>}

In the last case it doesn't call immediately and don't cause the re render of the function, hence avoiding infinite calls.

Get the second largest number in a list in linear time

Most of previous answers are correct but here is another way !

Our strategy is to create a loop with two variables first_highest and second_highest. We loop through the numbers and if our current_value is greater than the first_highest then we set second_highest to be the same as first_highest and then the second_highest to be the current number. If our current number is greater than second_highest then we set second_highest to the same as current numberenter image description here

#!/usr/bin/env python3
import sys
def find_second_highest(numbers):

    min_integer = -sys.maxsize -1
    first_highest= second_highest = min_integer
    for current_number in numbers:
        if current_number == first_highest and min_integer != second_highest:
        elif current_number > first_highest:
            second_highest = first_highest
            first_highest = current_number
        elif current_number > second_highest:
            second_highest = current_number
    return second_highest


How to select <td> of the <table> with javascript?

There begin to appear some answers that assume you want to get all <td> elements from #table. If so, the simplest cross-browser way how to do this is document.getElementById('table').getElementsByTagName('td'). This works because getElementsByTagName doesn't return only immediate children. No loops are needed.

How to lowercase a pandas dataframe string column if it has missing values?

copy your Dataframe column and simply apply


Dependent DLL is not getting copied to the build output folder in Visual Studio


Encountered with a similar issue for a NuGet package DLL (Newtonsoft.json.dll) where the build output doesn't include the referenced DLL. But the compilation goes thru fine.


Go through your projects in a text editor and look for references with "Private" tags in them. Like True or False. “Private” is a synonym for “Copy Local.” Somewhere in the actions, MSBuild is taking to locate dependencies, it’s finding your dependency somewhere else and deciding not to copy it.

So, go through each .csproj/.vbproj file and remove the tags manually. Rebuild, and everything works in both Visual Studio and MSBuild. Once you’ve got that working, you can go back in and update the to where you think they need to be.


Unique device identification

You can use the fingerprintJS2 library, it helps a lot with calculating a browser fingerprint.

By the way, on Panopticlick you can see how unique this usually is.

How do you revert to a specific tag in Git?

Use git reset:

git reset --hard "Version 1.0 Revision 1.5"

(assuming that the specified string is the tag).

Java Security: Illegal key size or default parameters?

There's a short discussion of what appears to be this issue here. The page it links to appears to be gone, but one of the responses might be what you need:

Indeed, copying US_export_policy.jar and local_policy.jar from core/lib/jce to $JAVA_HOME/jre/lib/security helped. Thanks.

How can strip whitespaces in PHP's variable?

Is old post but can be done like this:

if(!function_exists('strim')) :
function strim($str,$charlist=" ",$option=0){
        // Translate HTML entities
        $return = str_replace("&nbsp;"," ",$str);
        $return = strtr($return, array_flip(get_html_translation_table(HTML_ENTITIES, ENT_QUOTES)));
        // Choose trim option
            // Strip whitespace (and other characters) from the begin and end of string
            case 0:
                $return = trim($return,$charlist);
            // Strip whitespace (and other characters) from the begin of string 
            case 1:
                $return = ltrim($return,$charlist);
            // Strip whitespace (and other characters) from the end of string 
            case 2:
                $return = rtrim($return,$charlist);

    return $return;

Standard trim() functions can be a problematic when come HTML entities. That's why i wrote "Super Trim" function what is used to handle with this problem and also you can choose is trimming from the begin, end or booth side of string.

Ping with timestamp on Windows CLI

This might help someone : [Needs to be run in Windows PowerShell]

ping.exe -t |Foreach{"{0} - {1}" -f (Get-Date),$_} >> Ping_IP.txt

-- Check for the Ping_IP.txt file at the current directory or user home path.

Above command gives you output in a file like below ;

9/14/2018 8:58:48 AM - Pinging with 32 bytes of data:
9/14/2018 8:58:48 AM - Reply from bytes=32 time=29ms TTL=117
9/14/2018 8:58:49 AM - Reply from bytes=32 time=29ms TTL=117
9/14/2018 8:58:50 AM - Reply from bytes=32 time=28ms TTL=117
9/14/2018 8:58:51 AM - Reply from bytes=32 time=27ms TTL=117
9/14/2018 8:58:52 AM - Reply from bytes=32 time=28ms TTL=117
9/14/2018 8:58:53 AM - Reply from bytes=32 time=27ms TTL=117
9/14/2018 8:58:54 AM - Reply from bytes=32 time=28ms TTL=117

Apache 2.4 - Request exceeded the limit of 10 internal redirects due to probable configuration error

You're getting into looping most likely due to these rules:

RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L]

Just comment it out and try again in a new browser.

How do I use regular expressions in bash scripts?

You need spaces around the operator =~

if [[ $i =~ "200[78]" ]];
  echo "OK"
  echo "not OK"

Django TemplateDoesNotExist?

Hi guys I found a new solution. Actually it is defined in another template so instead of defining TEMPLATE_DIRS yourself, put your directory path name at their: enter image description here

Fastest way to tell if two files have the same contents in Unix/Linux?

Try also to use the cksum command:

chk1=`cksum <file1> | awk -F" " '{print $1}'`
chk2=`cksum <file2> | awk -F" " '{print $1}'`

if [ $chk1 -eq $chk2 ]
  echo "File is identical"
  echo "File is not identical"

The cksum command will output the byte count of a file. See 'man cksum'.

How to write oracle insert script with one field as CLOB?

Keep in mind that SQL strings can not be larger than 4000 bytes, while Pl/SQL can have strings as large as 32767 bytes. see below for an example of inserting a large string via an anonymous block which I believe will do everything you need it to do.

note I changed the varchar2(32000) to CLOB

set serveroutput ON 
CREATE TABLE testclob 
     id NUMBER, 
     c  CLOB, 
     d  VARCHAR2(4000) 

    reallybigtextstring CLOB := '123'; 
    i                   INT; 
    WHILE Length(reallybigtextstring) <= 60000 LOOP 
        reallybigtextstring := reallybigtextstring 
                               || '000000000000000000000000000000000'; 
    END LOOP; 

    INSERT INTO testclob 
    VALUES     (0, 

    dbms_output.Put_line('I have finished inputting your clob: ' 
                         || Length(reallybigtextstring)); 

FROM   testclob; 

 "I have finished inputting your clob: 60030"

Simple dynamic breadcrumb

Here is a great simple dynamic breadcrumb (tweak as needed):

    $docroot = "/zen/index5.php";
    $path =($_SERVER['REQUEST_URI']);
    $names = explode("/", $path); 
    $trimnames = array_slice($names, 1, -1);
    $length = count($trimnames)-1;
    $fixme = array(".php","-","myname");
    $fixes = array(""," ","My<strong>Name</strong>");
    echo '<div id="breadwrap"><ol id="breadcrumb">';
    $url = "";
    for ($i = 0; $i <= $length;$i++){
    $url .= $trimnames[$i]."/";
        if($i>0 && $i!=$length){
            echo '<li><a href="/'.$url.'">'.ucfirst(str_replace($fixme,$fixes,$trimnames[$i]) . ' ').'</a></li>';
    elseif ($i == $length){
        echo '<li class="current">'.ucfirst(str_replace($fixme,$fixes,$trimnames[$i]) . ' ').'</li>';       
        echo $trimnames[$i]='<li><a href='.$docroot.' id="bread-home"><span>&nbsp;</span></a></li>';
echo '</ol>';

CSS3 Transparency + Gradient

Here is my code:

background: #e8e3e3; /* Old browsers */
  background: -moz-linear-gradient(top,  rgba(232, 227, 227, 0.95) 0%, rgba(246, 242, 242, 0.95) 100%); /* FF3.6+ */
  background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(232, 227, 227, 0.95)), color-stop(100%,rgba(246, 242, 242, 0.95))); /* Chrome,Safari4+ */
  background: -webkit-linear-gradient(top,  rgba(232, 227, 227, 0.95) 0%,rgba(246, 242, 242, 0.95) 100%); /* Chrome10+,Safari5.1+ */
  background: -o-linear-gradient(top,  rgba(232, 227, 227, 0.95) 0%,rgba(246, 242, 242, 0.95) 100%); /* Opera 11.10+ */
  background: -ms-linear-gradient(top,  rgba(232, 227, 227, 0.95) 0%,rgba(246, 242, 242, 0.95) 100%); /* IE10+ */
  background: linear-gradient(to bottom,  rgba(232, 227, 227, 0.95) 0%,rgba(246, 242, 242, 0.95) 100%); /* W3C */
  filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='rgba(232, 227, 227, 0.95)', endColorstr='rgba(246, 242, 242, 0.95)',GradientType=0 ); /* IE6-9 */

Go install fails with error: no install location for directory xxx outside GOPATH

You'll want to have 3 directories inside your chosen GOPATH directory.


Then you'll run go install from inside either someProgram (which puts an executable in bin) or someLibrary (which puts a library in pkg).

In Bash, how can I check if a string begins with some value?

I tweaked @markrushakoff's answer to make it a callable function:

function yesNo {
  # Prompts user with $1, returns true if response starts with y or Y or is empty string
  read -e -p "
$1 [Y/n] " YN

  [[ "$YN" == y* || "$YN" == Y* || "$YN" == "" ]]

Use it like this:

$ if yesNo "asfd"; then echo "true"; else echo "false"; fi

asfd [Y/n] y

$ if yesNo "asfd"; then echo "true"; else echo "false"; fi

asfd [Y/n] Y

$ if yesNo "asfd"; then echo "true"; else echo "false"; fi

asfd [Y/n] yes

$ if yesNo "asfd"; then echo "true"; else echo "false"; fi

asfd [Y/n]

$ if yesNo "asfd"; then echo "true"; else echo "false"; fi

asfd [Y/n] n

$ if yesNo "asfd"; then echo "true"; else echo "false"; fi

asfd [Y/n] ddddd

Here is a more complex version that provides for a specified default value:

function toLowerCase {
  echo "$1" | tr '[:upper:]' '[:lower:]'

function yesNo {
  # $1: user prompt
  # $2: default value (assumed to be Y if not specified)
  # Prompts user with $1, using default value of $2, returns true if response starts with y or Y or is empty string

  local DEFAULT=yes
  if [ "$2" ]; then local DEFAULT="$( toLowerCase "$2" )"; fi
  if [[ "$DEFAULT" == y* ]]; then
    local PROMPT="[Y/n]"
    local PROMPT="[y/N]"
  read -e -p "

  YN="$( toLowerCase "$YN" )"
  { [ "$YN" == "" ] && [[ "$PROMPT" = *Y* ]]; } || [[ "$YN" = y* ]]

Use it like this:

$ if yesNo "asfd" n; then echo "true"; else echo "false"; fi

asfd [y/N]

$ if yesNo "asfd" n; then echo "true"; else echo "false"; fi

asfd [y/N] y

$ if yesNo "asfd" y; then echo "true"; else echo "false"; fi

asfd [Y/n] n

Python: Removing spaces from list objects

Strings in Python are immutable (meaning that their data cannot be modified) so the replace method doesn't modify the string - it returns a new string. You could fix your code as follows:

for i in hello:
    j = i.replace(' ','')

However a better way to achieve your aim is to use a list comprehension. For example the following code removes leading and trailing spaces from every string in the list using strip:

hello = [x.strip(' ') for x in hello]

Update ViewPager dynamically?

I have encountered this problem and finally solved it today, so I write down what I have learned and I hope it is helpful for someone who is new to Android's ViewPager and update as I do. I'm using FragmentStatePagerAdapter in API level 17 and currently have just 2 fragments. I think there must be something not correct, please correct me, thanks. enter image description here

  1. Serialized data has to be loaded into memory. This can be done using a CursorLoader/AsyncTask/Thread. Whether it's automatically loaded depends on your code. If you are using a CursorLoader, it's auto-loaded since there is a registered data observer.

  2. After you call viewpager.setAdapter(pageradapter), the adapter's getCount() is constantly called to build fragments. So if data is being loaded, getCount() can return 0, thus you don't need to create dummy fragments for no data shown.

  3. After the data is loaded, the adapter will not build fragments automatically since getCount() is still 0, so we can set the actually loaded data number to be returned by getCount(), then call the adapter's notifyDataSetChanged(). ViewPager begin to create fragments (just the first 2 fragments) by data in memory. It's done before notifyDataSetChanged() is returned. Then the ViewPager has the right fragments you need.

  4. If the data in the database and memory are both updated (write through), or just data in memory is updated (write back), or only data in the database is updated. In the last two cases if data is not automatically loaded from the database to memory (as mentioned above). The ViewPager and pager adapter just deal with data in memory.

  5. So when data in memory is updated, we just need to call the adapter's notifyDataSetChanged(). Since the fragment is already created, the adapter's onItemPosition() will be called before notifyDataSetChanged() returns. Nothing needs to be done in getItemPosition(). Then the data is updated.

CSS Animation and Display None

The following will get you to animate an element when

  1. Giving it a Display - None
  2. Giving it a Display - Block


.MyClass {
       opacity: 0;
       transition: opacity 0.5s linear;
       -webkit-transition: opacity 0.5s linear;
       -moz-transition: opacity 0.5s linear;
       -o-transition: opacity 0.5s linear;
       -ms-transition: opacity 0.5s linear;


function GetThisHidden(){
    $(".MyClass").css("opacity", "0").on('transitionend webkitTransitionEnd oTransitionEnd otransitionend', HideTheElementAfterAnimation);

function GetThisDisplayed(){
    $(".MyClass").css("display", "block").css("opacity", "1").unbind("transitionend webkitTransitionEnd oTransitionEnd otransitionend");

function HideTheElementAfterAnimation(){
    $(".MyClass").css("display", "none");

Using LINQ to group by multiple properties and sum

Linus is spot on in the approach, but a few properties are off. It looks like 'AgencyContractId' is your Primary Key, which is unrelated to the output you want to give the user. I think this is what you want (assuming you change your ViewModel to match the data you say you want in your view).

var agencyContracts = _agencyContractsRepository.AgencyContracts
    .GroupBy(ac => new
    .Select(ac => new AgencyContractViewModel
                       AgencyId = ac.Key.AgencyID,
                       VendorId = ac.Key.VendorID,
                       RegionId = ac.Key.RegionID,
                       Total = ac.Sum(acs => acs.Amount) + ac.Sum(acs => acs.Fee)

How to detect tableView cell touched or clicked in swift

I screw up on the every time! Just make sure the tableView delegate and dataSource are declared in viewDidLoad. Then I normally populate a few arrays to simulate returned data and then take it from there!

//******** Populate Table with data ***********
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{

    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell") as? SetupCellView
    cell?.ControllerLbl.text = ViewContHeading[indexPath.row]
    cell?.DetailLbl.text = ViewContDetail[indexPath.row]
    cell?.StartupImageImg.image = UIImage(named: ViewContImages[indexPath.row])
    return cell!

Getting date format m-d-Y H:i:s.u from milliseconds

You can readily do this this with the input format U.u.

$now = DateTime::createFromFormat('U.u', microtime(true));
echo $now->format("m-d-Y H:i:s.u");

This produces the following output:

04-13-2015 05:56:22.082300

From the PHP manual page for date formats:

  • U = Seconds since the Unix Epoch
  • u = Microseconds

Thanks goes to giggsey for pointing out a flaw in my original answer, adding number_format() to the line should fix the case of the exact second. Too bad it doesn't feel quite as elegant any more...

$now = DateTime::createFromFormat('U.u', number_format(microtime(true), 6, '.', ''));

A note on time zones in response to DaVe.

Normally the createFromFormat() method will use the local time zone if one is not specified.

However, the technique described here is initialising the DateTime object using microtime() which returns the number of seconds elapsed since the Unix Epoch (01 Jan 1970 00:00:00 GMT).

This means that the DateTime object is implicitly initialised to UTC, which is fine for server internal tasks that just want to track elapsed time.

If you need to display the time for a particular time zone then you need to set it accordingly. However, this should be done as a separate step after the initialisation (not using the third parameter of createFromFormat()) because of the reasons discussed above.

The setTimeZone() method can be used to accomplish this requirement.

As an example:

$now = DateTime::createFromFormat('U.u', number_format(microtime(true), 6, '.', ''));
echo $now->format("m-d-Y H:i:s.u") . '<br>';

$local = $now->setTimeZone(new DateTimeZone('Australia/Canberra'));
echo $local->format("m-d-Y H:i:s.u") . '<br>';

Produces the following output:

10-29-2015 00:40:09.433818
10-29-2015 11:40:09.433818

Note that if you want to input into mysql, the time format needs to be:

format("Y-m-d H:i:s.u")

Creating C formatted strings (not printing them)

Use sprintf.

int sprintf ( char * str, const char * format, ... );

Write formatted data to string Composes a string with the same text that would be printed if format was used on printf, but instead of being printed, the content is stored as a C string in the buffer pointed by str.

The size of the buffer should be large enough to contain the entire resulting string (see snprintf for a safer version).

A terminating null character is automatically appended after the content.

After the format parameter, the function expects at least as many additional arguments as needed for format.



Pointer to a buffer where the resulting C-string is stored. The buffer should be large enough to contain the resulting string.


C string that contains a format string that follows the same specifications as format in printf (see printf for details).

... (additional arguments)

Depending on the format string, the function may expect a sequence of additional arguments, each containing a value to be used to replace a format specifier in the format string (or a pointer to a storage location, for n). There should be at least as many of these arguments as the number of values specified in the format specifiers. Additional arguments are ignored by the function.


// Allocates storage
char *hello_world = (char*)malloc(13 * sizeof(char));
// Prints "Hello world!" on hello_world
sprintf(hello_world, "%s %s!", "Hello", "world");

Get the current cell in Excel VB

Have you tried:

For one cell:


For multiple selected cells:


For example:

Dim rng As Range
Set rng = Range(Selection.Address)

mysql alphabetical order

i want to show records only starting with b

select name from user where name LIKE 'b%';

i am trying to sort MySQL data alphabeticaly

select name from user ORDER BY name;

i am trying to sort MySQL data in reverse alphabetic order

select name from user ORDER BY name desc;

How to set different colors in HTML in one statement?

You could use CSS for this and create classes for the elements. So you'd have something like this

p.detail { color:#4C4C4C;font-weight:bold;font-family:Calibri;font-size:20 } { color:#FF0000;font-weight:bold;font-family:Tahoma;font-size:20 }

Then your HTML would read:

<p class="detail">My Name is: <span class="name">Tintinecute</span> </p>

It's a lot neater then inline stylesheets, is easier to maintain and provides greater reuse.

Here's the complete HTML to demonstrate what I mean:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">
<html xmlns="">
    <style type="text/css">
    p.detail { color:#4C4C4C;font-weight:bold;font-family:Calibri;font-size:20 } { color:#FF0000;font-weight:bold;font-family:Tahoma;font-size:20 }
    <p class="detail">My Name is: <span class="name">Tintinecute</span> </p>

You'll see that I have the stylesheet classes in a style tag in the header, and then I only apply those classes in the code such as <p class="detail"> ... </p>. Go through the w3schools tutorial, it will only take a couple of hours and will really turn you around when it comes to styling your HTML elements. If you cut and paste that into an HTML document you can edit the styles and see what effect they have when you open the file in a browser. Experimenting like this is a great way to learn.


Maybe try this

Select cust.*

From dbo.Customers cust
Left Join dbo.Subscribers subs on cust.Customer_ID = subs.Customer_ID
Where subs.Customer_Id Is Null

How can I include all JavaScript files in a directory via JavaScript file?

I was looking for an answer to this question and had my own problems. I found a couple solutions in various places and put them together into my own preferred answer.

function exploreFolder(folderURL,options){
/* options:                 type            explaination

    **REQUIRED** callback:  FUNCTION        function to be called on each file. passed the complete filepath
    then:                   FUNCTION        function to be called after loading all files in folder. passed the number of files loaded
    recursive:              BOOLEAN         specifies wether or not to travel deep into folders
    ignore:                 REGEX           file names matching this regular expression will not be operated on
    accept:                 REGEX           if this is present it overrides the `ignore` and only accepts files matching the regex
    url: folderURL,
    success: function(data){
        var filesLoaded = 0,
        fileName = '';

        $(data).find("td > a").each(function(){
            fileName = $(this).attr("href");

            if(fileName === '/')
                return;  //to account for the (go up a level) link

            if(/\/\//.test(folderURL + fileName))
                return; //if the url has two consecutive slashes '//'

                    //if accept is present and the href fails, dont callback
            }else if(options.ignore)
                    //if ignore is present and the href passes, dont callback

            if(fileName.length > 1 && fileName.substr(fileName.length-1) === "/")
                    //only recurse if we are told to
                    exploreFolder(folderURL + fileName, options);

            options.callback(folderURL + fileName);
            //pass the full URL into the callback function
        if(options.then && filesLoaded > 0) options.then(filesLoaded);

Then you can call it like this:

var loadingConfig = {
    callback: function(file) { console.log("Loaded file: " + file); },
    then: function(numFiles) { console.log("Finished loading " + numFiles + " files"); },
    recursive: true,
    ignore: /^NOLOAD/,
exploreFolder('/someFolderURL/', loadingConfig);

This example will call that callback on every file/folder in the specified folder except for ones that start with NOLOAD. If you want to actually load the file into the page then you can use this other helper function that I developed.

function getFileExtension(fname){
        return fname.substr((~-fname.lastIndexOf(".") >>> 0) + 2);
    console.warn("No file name provided");
var loadFile = (function(filename){
    var img = new Image();

    return function(){
        var fileref,
            filename = arguments[0],
            filetype = getFileExtension(filename).toLowerCase();

        switch (filetype) {
            case '':
            case 'js':
                fileref.setAttribute("src", filename);
            case "css":
                fileref.setAttribute("rel", "stylesheet");
                fileref.setAttribute("type", "text/css");
                fileref.setAttribute("href", filename);
            case "jpg":
            case "jpeg":
            case 'png':
            case 'gif':
                img.src = filename;
                console.warn("This file type is not supported: "+filetype);
        if (typeof fileref !== undefined){
            console.log('Loaded file: ' + filename);

This function accepts a JS | CSS | (common image) file and loads it. It will also execute the JS files. The complete call that needs to be run in your script to load all images and* stylesheets and other scripts could look like this:

loadingConfig = {
    callback: loadfile,
    then: function(numFiles) { console.log("Finished loading " + numFiles + " files"); },
    recursive: true,
    ignore: /^NOLOAD/,
exploreFolder('/someFolderURL/', loadingConfig);

It works amazingly!

How do you get a list of the names of all files present in a directory in Node.js?

My 2 cents if someone:

Just want to list file names (excluding directories) from a local sub-folder on their project

  • ? No additional dependencies
  • ? 1 function
  • ? Normalize path (Unix vs. Windows)
const fs = require("fs");
const path = require("path");

 * @param {string} relativeName "resources/foo/goo"
 * @return {string[]}
const listFileNames = (relativeName) => {
  try {
    const folderPath = path.join(process.cwd(), ...relativeName.split("/"));
    return fs
      .readdirSync(folderPath, { withFileTypes: true })
      .filter((dirent) => dirent.isFile())
      .map((dirent) =>".")[0]);
  } catch (err) {
    // ...
 |-- countries
    |-- usa.yaml
    |-- japan.yaml
    |-- gb.yaml
    |-- provinces
       |-- .........

listFileNames("resources/countries") #=> ["usa", "japan", "gb"]

How to install xgboost in Anaconda Python (Windows platform)?

This simple helped me you don't have to include anything at the end because if you include something, some of your packages will be upgraded but some will be downgraded. You can get this from this url:

conda install -c anaconda py-xgboost 

Jasmine JavaScript Testing - toBe vs toEqual

Thought someone might like explanation by (annotated) example:

Below, if my deepClone() function does its job right, the test (as described in the 'it()' call) will succeed:

describe('deepClone() array copy', ()=>{
    let source:any = {}
    let clone:any = source
        source.a = [1,'string literal',{x:10, obj:{y:4}}]
        clone = Utils.deepClone(source) // THE CLONING ACT TO BE TESTED - lets see it it does it right.
    it('should create a clone which has unique identity, but equal values as the source object',()=>{
        expect(source !== clone).toBe(true) // If we have different object instances...
        expect(source).not.toBe(clone) // <= synonymous to the above. Will fail if: you remove the '.not', and if: the two being compared are indeed different objects.
        expect(source).toEqual(clone) // ...that hold same values, all tests will succeed.

Of course this is not a complete test suite for my deepClone(), as I haven't tested here if the object literal in the array (and the one nested therein) also have distinct identity but same values.

Different ways of adding to Dictionary

To insert the Value into the Dictionary

 Dictionary<string, string> dDS1 = new Dictionary<string, string>();//Declaration
 dDS1.Add("VEqpt", "aaaa");//adding key and value into the dictionary
 string Count = dDS1["VEqpt"];//assigning the value of dictionary key to Count variable
 dDS1["VEqpt"] = Count + "bbbb";//assigning the value to key

Where does mysql store data?

as @PhilHarvey said, you can use mysqld --verbose --help | grep datadir

How to vertically align label and input in Bootstrap 3?

I'm sure you've found your answer by now, but for those who are still looking for an answer:

When input-lg is used, margins mismatch unless you use form-group-lg in addition to form-group class. Its example is in docs:

<form class="form-horizontal">
  <div class="form-group form-group-lg">
    <label class="col-sm-2 control-label" for="formGroupInputLarge">Large label</label>
    <div class="col-sm-10">
      <input class="form-control" type="text" id="formGroupInputLarge" placeholder="Large input">
  <div class="form-group form-group-sm">
    <label class="col-sm-2 control-label" for="formGroupInputSmall">Small label</label>
    <div class="col-sm-10">
      <input class="form-control" type="text" id="formGroupInputSmall" placeholder="Small input">

Change url query string value using jQuery

If you only need to modify the page num you can replace it:

var newUrl = location.href.replace("page="+currentPageNum, "page="+newPageNum);

Why does flexbox stretch my image rather than retaining aspect ratio?

The key attribute is align-self: center:

.container {_x000D_
  display: flex;_x000D_
  flex-direction: column;_x000D_
img {_x000D_
  max-width: 100%;_x000D_
img.align-self {_x000D_
  align-self: center;_x000D_
<div class="container">_x000D_
    <p>Without align-self:</p>_x000D_
    <img src="" />_x000D_
    <p>With align-self:</p>_x000D_
    <img class="align-self" src="" />_x000D_

How can I test an AngularJS service from the console?

TLDR: In one line the command you are looking for:


Deep dive

AngularJS uses Dependency Injection (DI) to inject services/factories into your components,directives and other services. So what you need to do to get a service is to get the injector of AngularJS first (the injector is responsible for wiring up all the dependencies and providing them to components).

To get the injector of your app you need to grab it from an element that angular is handling. For example if your app is registered on the body element you call injector = angular.element(document.body).injector()

From the retrieved injector you can then get whatever service you like with injector.get('ServiceName')

More information on that in this answer: Can't retrieve the injector from angular
And even more here: Call AngularJS from legacy code

Another useful trick to get the $scope of a particular element. Select the element with the DOM inspection tool of your developer tools and then run the following line ($0 is always the selected element):

How to check if NSString begins with a certain character

You can use the -hasPrefix: method of NSString:


NSString* output = nil;
if([string hasPrefix:@"*"]) {
    output = [string substringFromIndex:1];


var output:String?
if string.hasPrefix("*") {
    output = string.substringFromIndex(string.startIndex.advancedBy(1))

Communicating between a fragment and an activity - best practices

You can create declare a public interface with a function declaration in the fragment and implement the interface in the activity. Then you can call the function from the fragment.