Programs & Examples On #Non greedy

A technique used in regular expressions, that limits the matching text until all conditions of the given regex have been met. The operator "?" is added to the end of wildcard operations.

What do 'lazy' and 'greedy' mean in the context of regular expressions?

As far as I know, most regex engine is greedy by default. Add a question mark at the end of quantifier will enable lazy match.

As @Andre S mentioned in comment.

  • Greedy: Keep searching until condition is not satisfied.
  • Lazy: Stop searching once condition is satisfied.

Refer to the example below for what is greedy and what is lazy.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Test {
    public static void main(String args[]){
        String money = "100000000999";
        String greedyRegex = "100(0*)";
        Pattern pattern = Pattern.compile(greedyRegex);
        Matcher matcher = pattern.matcher(money);
            System.out.println("I'm greeedy and I want " + + " dollars. This is the most I can get.");

        String lazyRegex = "100(0*?)";
        pattern = Pattern.compile(lazyRegex);
        matcher = pattern.matcher(money);
            System.out.println("I'm too lazy to get so much money, only " + + " dollars is enough for me");

The result is:

I'm greeedy and I want 100000000 dollars. This is the most I can get.

I'm too lazy to get so much money, only 100 dollars is enough for me

What is the difference between .*? and .* regular expressions?

It is the difference between greedy and non-greedy quantifiers.

Consider the input 101000000000100.

Using 1.*1, * is greedy - it will match all the way to the end, and then backtrack until it can match 1, leaving you with 1010000000001.
.*? is non-greedy. * will match nothing, but then will try to match extra characters until it matches 1, eventually matching 101.

All quantifiers have a non-greedy mode: .*?, .+?, .{2,6}?, and even .??.

In your case, a similar pattern could be <([^>]*)> - matching anything but a greater-than sign (strictly speaking, it matches zero or more characters other than > in-between < and >).

See Quantifier Cheat Sheet.

How can I write a regex which matches non greedy?

The ? operand makes match non-greedy. E.g. .* is greedy while .*? isn't. So you can use something like <img.*?> to match the whole tag. Or <img[^>]*>.

But remember that the whole set of HTML can't be actually parsed with regular expressions.

Add text to Existing PDF using Python

pdfrw will let you read in pages from an existing PDF and draw them to a reportlab canvas (similar to drawing an image). There are examples for this in the pdfrw examples/rl1 subdirectory on github. Disclaimer: I am the pdfrw author.

WHERE IS NULL, IS NOT NULL or NO WHERE clause depending on SQL Server parameter value

You could just do something like this:

FROM foo
WHERE (@param = 0 AND MyColumn IS NULL)
OR (@param = 1 AND MyColumn IS NOT NULL)
OR (@param = 2)

Something like that.

EOL conversion in notepad ++

That functionality is already built into Notepad++. From the "Edit" menu, select "EOL Conversion" -> "UNIX/OSX Format".

screenshot of the option for even quicker finding (or different language versions)

You can also set the default EOL in notepad++ via "Settings" -> "Preferences" -> "New Document/Default Directory" then select "Unix/OSX" under the Format box.

What is the difference between <html lang="en"> and <html lang="en-US">?

Well, the first question is easy. There are many ens (Englishes) but (mostly) only one US English. One would guess there are en-CN, en-GB, en-AU. Guess there might even be Austrian English but that's more yes you can than yes there is.

Removing Data From ElasticSearch

simplest way !

Endpoint :

Payload :
  "query": { 
    "match": {
      "message": "some message"

where twitter is the index in elastic search

ref ;

Iteration ng-repeat only X times in AngularJs

This is the simplest workaround I could think of.

<span ng-repeat="n in [].constructor(5) track by $index">

Here's a Plunker example.

How to redirect a URL path in IIS?

If you have loads of re-directs to create, having loads of virtual directories over the places is a nightmare to maintain. You could try using ISAPI redirect an IIS extension. Then all you re-directs are managed in one place.

It allows also you to match patterns based on reg ex expressions etc. I've used where I've had to re-direct 100's of pages and its saved a lot of time.

Browser can't access/find relative resources like CSS, images and links when calling a Servlet which forwards to a JSP

Your welcome page is set as That Servlet . So all css , images path should be given relative to that servlet DIR . which is a bad idea ! why do you need the servlet as a home page ? set .jsp as index page and redirect to any page from there ?

are you trying to populate any fields from db is that why you are using servlet ?

Why isn't .ico file defined when setting window's icon?

No way what is suggested here works - the error "bitmap xxx not defined" is ever present. And yes, I set the correct path to it.

What it did work is this:

imgicon = PhotoImage(file=os.path.join(sp,'myicon.gif'))'wm', 'iconphoto', root._w, imgicon)  

where sp is the script path, and root the Tk root window.

It's hard to understand how it does work (I shamelessly copied it from fedoraforums) but it works

What causing this "Invalid length for a Base-64 char array"

int len = qs.Length % 4;
            if (len > 0) qs = qs.PadRight(qs.Length + (4 - len), '=');

where qs is any base64 encoded string

Eclipse - Installing a new JRE (Java SE 8 1.8.0)

You can have many java versions in your system.

I think you should add the java 8 in yours JREs installed or edit.

Take a look my screen:

enter image description here

If you click in edit (check your java 8 path):

enter image description here

How do I rename all folders and files to lowercase on Linux?

A concise version using the "rename" command:

find my_root_dir -depth -exec rename 's/(.*)\/([^\/]*)/$1\/\L$2/' {} \;

This avoids problems with directories being renamed before files and trying to move files into non-existing directories (e.g. "A/A" into "a/a").

Or, a more verbose version without using "rename".

for SRC in `find my_root_dir -depth`
    DST=`dirname "${SRC}"`/`basename "${SRC}" | tr '[A-Z]' '[a-z]'`
    if [ "${SRC}" != "${DST}" ]
        [ ! -e "${DST}" ] && mv -T "${SRC}" "${DST}" || echo "${SRC} was not renamed"


The latter allows more flexibility with the move command (for example, "svn mv").

How to display Woocommerce product price by ID number on a custom page?

In woocommerce,

Get regular price :

$price = get_post_meta( get_the_ID(), '_regular_price', true);
// $price will return regular price

Get sale price:

$sale = get_post_meta( get_the_ID(), '_sale_price', true);
// $sale will return sale price

shorthand If Statements: C#

To use shorthand to get the direction:

int direction = column == 0
                ? 0
                : (column == _gridSize - 1 ? 1 : rand.Next(2));

To simplify the code entirely:

if (column == gridSize - 1 || rand.Next(2) == 1)

How to force R to use a specified factor level as reference in a regression?

The relevel() command is a shorthand method to your question. What it does is reorder the factor so that whatever is the ref level is first. Therefore, reordering your factor levels will also have the same effect but gives you more control. Perhaps you wanted to have levels 3,4,0,1,2. In that case...

bFactor <- factor(b, levels = c(3,4,0,1,2))

I prefer this method because it's easier for me to see in my code not only what the reference was but the position of the other values as well (rather than having to look at the results for that).

NOTE: DO NOT make it an ordered factor. A factor with a specified order and an ordered factor are not the same thing. lm() may start to think you want polynomial contrasts if you do that.

Use css gradient over background image

body {
    margin: 0;
    padding: 0;
    background: url('img/background.jpg') repeat;

body:before {
    content: " ";
    width: 100%;
    height: 100%;
    position: absolute;
    z-index: -1;
    top: 0;
    left: 0;
    background: -webkit-radial-gradient(top center, ellipse cover, rgba(255,255,255,0.2) 0%,rgba(0,0,0,0.5) 100%);

PLEASE NOTE: This only using webkit so it will only work in webkit browsers.

try :

-moz-linear-gradient = (Firefox)
-ms-linear-gradient = (IE)
-o-linear-gradient = (Opera)
-webkit-linear-gradient = (Chrome & safari)

How to plot two histograms together in R?

Here's the version like the ggplot2 one I gave only in base R. I copied some from @nullglob.

generate the data

carrots <- rnorm(100000,5,2)
cukes <- rnorm(50000,7,2.5)

You don't need to put it into a data frame like with ggplot2. The drawback of this method is that you have to write out a lot more of the details of the plot. The advantage is that you have control over more details of the plot.

## calculate the density - don't plot yet
densCarrot <- density(carrots)
densCuke <- density(cukes)
## calculate the range of the graph
xlim <- range(densCuke$x,densCarrot$x)
ylim <- range(0,densCuke$y, densCarrot$y)
#pick the colours
carrotCol <- rgb(1,0,0,0.2)
cukeCol <- rgb(0,0,1,0.2)
## plot the carrots and set up most of the plot parameters
plot(densCarrot, xlim = xlim, ylim = ylim, xlab = 'Lengths',
     main = 'Distribution of carrots and cucumbers', 
     panel.first = grid())
#put our density plots in
polygon(densCarrot, density = -1, col = carrotCol)
polygon(densCuke, density = -1, col = cukeCol)
## add a legend in the corner
       fill = c(carrotCol, cukeCol), bty = 'n',
       border = NA)

enter image description here

Rename multiple files in cmd

I was puzzled by this also... didn't like the parentheses that windows puts in when you rename in bulk. In my research I decided to write a script with PowerShell instead. Super easy and worked like a charm. Now I can use it whenever I need to batch process file renaming... which is frequent. I take hundreds of photos and the camera names them IMG1234.JPG etc...

Here is the script I wrote:

# filename: bulk_file_rename.ps1
# by: subcan
# PowerShell script to rename multiple files within a folder to a 
# name that increments without (#)
# create counter
$int = 1
# ask user for what they want
$regex = Read-Host "Regex for files you are looking for? ex. IMG*.JPG "
$file_name = Read-Host "What is new file name, without extension? ex. New Image "
$extension = Read-Host "What extension do you want? ex. .JPG "
# get a total count of the files that meet regex
$total = Get-ChildItem -Filter $regex | measure
# while loop to rename all files with new name
while ($int -le $total.Count)
    # diplay where in loop you are
    Write-Host "within while loop" $int  
    # create variable for concatinated new name - 
    # $int.ToString(000) ensures 3 digit number 001, 010, etc
    $new_name = $file_name + $int.ToString(000)+$extension
    # get the first occurance and rename
    Get-ChildItem -Filter $regex | select -First 1 | Rename-Item -NewName $new_name
    # display renamed file name
    Write-Host "Renamed to" $new_name
    # increment counter

I hope that this is helpful to someone out there.


What is the difference between Swing and AWT?

AWT is a Java interface to native system GUI code present in your OS. It will not work the same on every system, although it tries.

Swing is a more-or-less pure-Java GUI. It uses AWT to create an operating system window and then paints pictures of buttons, labels, text, checkboxes, etc., into that window and responds to all of your mouse-clicks, key entries, etc., deciding for itself what to do instead of letting the operating system handle it. Thus Swing is 100% portable and is the same across platforms (although it is skinnable and has a "pluggable look and feel" that can make it look more or less like how the native windows and widgets would look).

These are vastly different approaches to GUI toolkits and have a lot of consequences. A full answer to your question would try to explore all of those. :) Here are a couple:

AWT is a cross-platform interface, so even though it uses the underlying OS or native GUI toolkit for its functionality, it doesn't provide access to everything that those toolkits can do. Advanced or newer AWT widgets that might exist on one platform might not be supported on another. Features of widgets that aren't the same on every platform might not be supported, or worse, they might work differently on each platform. People used to invest lots of effort to get their AWT applications to work consistently across platforms - for instance, they may try to make calls into native code from Java.

Because AWT uses native GUI widgets, your OS knows about them and handles putting them in front of each other, etc., whereas Swing widgets are meaningless pixels within a window from your OS's point of view. Swing itself handles your widgets' layout and stacking. Mixing AWT and Swing is highly unsupported and can lead to ridiculous results, such as native buttons that obscure everything else in the dialog box in which they reside because everything else was created with Swing.

Because Swing tries to do everything possible in Java other than the very raw graphics routines provided by a native GUI window, it used to incur quite a performance penalty compared to AWT. This made Swing unfortunately slow to catch on. However, this has shrunk dramatically over the last several years due to more optimized JVMs, faster machines, and (I presume) optimization of the Swing internals. Today a Swing application can run fast enough to be serviceable or even zippy, and almost indistinguishable from an application using native widgets. Some will say it took far too long to get to this point, but most will say that it is well worth it.

Finally, you might also want to check out SWT (the GUI toolkit used for Eclipse, and an alternative to both AWT and Swing), which is somewhat of a return to the AWT idea of accessing native Widgets through Java.

How to update column with null value

If you want to set null value using update query set column value to NULL (without quotes) update tablename set columnname = NULL

However, if you are directly editing field value inside mysql workbench then use (Esc + del) keystroke to insert null value into selected column

SHA-256 or MD5 for file integrity

To 1): Yes, on most CPUs, SHA-256 is about only 40% as fast as MD5.

To 2): I would argue for a different algorithm than MD5 in such a case. I would definitely prefer an algorithm that is considered safe. However, this is more a feeling. Cases where this matters would be rather constructed than realistic, e.g. if your backup system encounters an example case of an attack on an MD5-based certificate, you are likely to have two files in such an example with different data, but identical MD5 checksums. For the rest of the cases, it doesn't matter, because MD5 checksums have a collision (= same checksums for different data) virtually only when provoked intentionally. I'm not an expert on the various hashing (checksum generating) algorithms, so I can not suggest another algorithm. Hence this part of the question is still open. Suggested further reading is Cryptographic Hash Function - File or Data Identifier on Wikipedia. Also further down on that page there is a list of cryptographic hash algorithms.

To 3): MD5 is an algorithm to calculate checksums. A checksum calculated using this algorithm is then called an MD5 checksum.

String isNullOrEmpty in Java? string) from Google Guava

Android Emulator sdcard push error: Read-only file system

Alternate way: Dismount the drive (from settings/storage) and re-mount the sdcard also fixes the problem. (verify by moving a file from internal storage to sdcard) In any case, this simple method saved my butt this time :)

Jinja2 shorthand conditional

Alternative way (but it's not python style. It's JS style)

{{ files and 'Update' or 'Continue' }}

Using Google maps API v3 how do I get LatLng with a given address?

If you need to do this on the backend you can use the following URL structure:[STREET_ADDRESS]&key=[YOUR_API_KEY]

Sample PHP code using curl:

$curl = curl_init();

curl_setopt($curl, CURLOPT_URL, '' . rawurlencode($address) . '&key=' . $api_key);

curl_setopt ($curl, CURLOPT_RETURNTRANSFER, 1);

$json = curl_exec($curl);

curl_close ($curl);

$obj = json_decode($json);

See additional documentation for more details and expected json response.

The docs provide sample output and will assist you in getting your own API key in order to be able to make requests to the Google Maps Geocoding API.

Using Python Requests: Sessions, Cookies, and POST

I don't know how stubhub's api works, but generally it should look like this:

s = requests.Session()
data = {"login":"my_login", "password":"my_password"}
url = ""
r =, data=data)

Now your session contains cookies provided by login form. To access cookies of this session simply use


Any further actions like another requests will have this cookie

dynamically set iframe src

Try this:


How to download HTTP directory with all files and sub-directories as they appear on the online files/folders list?

you can use lftp, the swish army knife of downloading if you have bigger files you can add --use-pget-n=10 to command

lftp -c 'mirror --parallel=100 ;exit'

Hexadecimal to Integer in Java

Try this

public static long Hextonumber(String hexval)
//      String decimal="0x00000bb9";
        Long number = Long.decode(hexval);
//.......       System.out.println("String [" + hexval + "] = " + number);
        return number;

Multiplication on command line terminal

If you like python and have an option to install a package, you can use this utility that I made.

# install pythonp
python -m pip install pythonp

pythonp "5*5"

pythonp "1 / (1+math.exp(0.5))"

# define a custom function and pass it to another higher-order function
pythonp "n=10;functools.reduce(lambda x,y:x*y, range(1,n+1))"     

How to prevent multiple definitions in C?

You shouldn't include other source files (*.c) in .c files. I think you want to have a header (.h) file with the DECLARATION of test function, and have it's DEFINITION in a separate .c file.

The error is caused by multiple definitions of the test function (one in test.c and other in main.c)

create multiple tag docker image

How not to do it:

When building an image, you could also tag it this way.

docker build -t ubuntu:14.04 .

Then you build it again with another tag:

docker build -t ubuntu:latest .

If your Dockerfile makes good use of the cache, the same image should come out, and it effectively does the same as retagging the same image. If you do docker images then you will see that they have the same ID.

There's probably a case where this goes wrong though... But like @david-braun said, you can't create tags with Dockerfiles themselves, just with the docker command.

C++ display stack trace on exception

Since the stack is already unwound when entering the catch block, the solution in my case was to not catch certain exceptions which then lead to a SIGABRT. In the signal handler for SIGABRT I then fork() and execl() either gdb (in debug builds) or Google breakpads stackwalk (in release builds). Also I try to only use signal handler safe functions.


static const char BACKTRACE_START[] = "<2>--- backtrace of entire stack ---\n";
static const char BACKTRACE_STOP[] = "<2>--- backtrace finished ---\n";

static char *ltrim(char *s)
    while (' ' == *s) {
    return s;

void Backtracer::print()
    int child_pid = ::fork();
    if (child_pid == 0) {
        // redirect stdout to stderr
        ::dup2(2, 1);

        // create buffer for parent pid (2+16+1 spaces to allow up to a 64 bit hex parent pid)
        char pid_buf[32];
        const char* stem = "                   ";
        const char* s = stem;
        char* d = &pid_buf[0];
        while (static_cast<bool>(*s))
            *d++ = *s++;
        *d-- = '\0';
        char* hexppid = d;

        // write parent pid to buffer and prefix with 0x
        int ppid = getppid();
        while (ppid != 0) {
            *hexppid = ((ppid & 0xF) + '0');
            if(*hexppid > '9') {
                *hexppid += 'a' - '0' - 10;
            ppid >>= 4;
        *hexppid-- = 'x';
        *hexppid = '0';

        // invoke GDB
        char name_buf[512];
        name_buf[::readlink("/proc/self/exe", &name_buf[0], 511)] = 0;
        ssize_t r = ::write(STDERR_FILENO, &BACKTRACE_START[0], sizeof(BACKTRACE_START));
                "/usr/bin/gdb", "--batch", "-n", "-ex", "thread apply all bt full", "-ex", "quit",
                &name_buf[0], ltrim(&pid_buf[0]), nullptr);
        ::exit(1); // if GDB failed to start
    } else if (child_pid == -1) {
        ::exit(1); // if forking failed
    } else {
        // make it work for non root users
        if (0 != getuid()) {
            ::prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, 0, 0, 0);
        ::waitpid(child_pid, nullptr, 0);
        ssize_t r = ::write(STDERR_FILENO, &BACKTRACE_STOP[0], sizeof(BACKTRACE_STOP));


static bool dumpCallback(const google_breakpad::MinidumpDescriptor& descriptor, void* context, bool succeeded)
    int child_pid = ::fork();
    if (child_pid == 0) {
        ::dup2(open("/dev/null", O_WRONLY), 2); // ignore verbose output on stderr
        ::execl("/usr/bin/minidump_stackwalk", "/usr/bin/minidump_stackwalk", descriptor.path(), "/usr/share/breakpad-syms", nullptr);
        ::exit(1); // if minidump_stackwalk failed to start
    } else if (child_pid == -1) {
        ::exit(1); // if forking failed
    } else {
        ::waitpid(child_pid, nullptr, 0);
    ::remove(descriptor.path()); // this is not signal safe anymore but should still work
    return succeeded;

Edit: To make it work for breakpad I also had to add this:

    ssize_t r = ::write(STDERR_FILENO, EXCEPTION, sizeof(EXCEPTION));
    google_breakpad::ExceptionHandler::WriteMinidump(std::string("/tmp"), dumpCallback, NULL);
    exit(1); // avoid creating a second dump by not calling std::abort

Source: How to get a stack trace for C++ using gcc with line number information? and Is it possible to attach gdb to a crashed process (a.k.a "just-in-time" debugging)

Plot multiple lines in one graph

You should bring your data into long (i.e. molten) format to use it with ggplot2:

mdf <- melt(mdf, id.vars="Company","value","Year")

And then you have to use aes( ... , group = Company ) to group them:

ggplot(data=mdf, aes(x=Year, y=value, group = Company, colour = Company)) +
    geom_line() +
    geom_point( size=4, shape=21, fill="white")

enter image description here

NameError: name 'reduce' is not defined in Python

You can add

from functools import reduce

before you use the reduce.

400 BAD request HTTP error code meaning?

Selecting a HTTP response code is quite an easy task and can be described by simple rules. The only tricky part which is often forgotten is paragraph 6.5 from RFC 7231:

Except when responding to a HEAD request, the server SHOULD send a representation containing an explanation of the error situation, and whether it is a temporary or permanent condition.

Rules are as following:

  1. If request was successful, then return 2xx code (3xx for redirect). If there was an internal logic error on a server, then return 5xx. If there is anything wrong in client request, then return 4xx code.
  2. Look through available response code from selected category. If one of them has a name which matches well to your situation, you can use it. Otherwise just fallback to x00 code (200, 400, 500). If you doubt, fallback to x00 code.
  3. Return error description in response body. For 4xx codes it must contain enough information for client developer to understand the reason and fix the client. For 5xx because of security reasons no details must be revealed.
  4. If client needs to distinguish different errors and have different reaction depending on it, define a machine readable and extendible error format and use it everywhere in your API. It is good practice to make that from very beginning.
  5. Keep in mind that client developer may do strange things and try to parse strings which you return as human readable description. And by changing the strings you will break such badly written clients. So always provide machine readable description and try to avoid reporting additional information in text.

So in your case I'd returned 400 error and something like this if "Roman" is obtained from user input and client must have specific reaction:

    "error_type" : "unsupported_resource",
    "error_description" : "\"Roman\" is not supported"

or a more generic error, if such situation is a bad logic error in a client and is not expected, unless developer made something wrong:

    "error_type" : "malformed_json",
    "error_description" : "\"Roman\" is not supported for \"requestedResource\" field"

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

Use the oncontextmenu event.

Here's an example:

<div oncontextmenu="javascript:alert('success!');return false;">
    Lorem Ipsum

And using event listeners (credit to rampion from a comment in 2011):

el.addEventListener('contextmenu', function(ev) {
    return false;
}, false);

Don't forget to return false, otherwise the standard context menu will still pop up.

If you are going to use a function you've written rather than javascript:alert("Success!"), remember to return false in BOTH the function AND the oncontextmenu attribute.

Write objects into file with Node.js

If you're geting [object object] then use JSON.stringify

fs.writeFile('./data.json', JSON.stringify(obj) , 'utf-8');

It worked for me.

Soft keyboard open and close listener in an activity in Android

For Activity:

    final View activityRootView = findViewById(;
activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            public void onGlobalLayout() {
                Rect r = new Rect();


                int heightDiff = view.getRootView().getHeight() - (r.bottom -;
                if (heightDiff > 100) { 
                 //enter your code here
                 //enter code for hid

For Fragment:

    view = inflater.inflate(R.layout.live_chat_fragment, null);
view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            public void onGlobalLayout() {
                Rect r = new Rect();
                //r will be populated with the coordinates of your view that area still visible.

                int heightDiff = view.getRootView().getHeight() - (r.bottom -;
                if (heightDiff > 500) { // if more than 100 pixels, its probably a keyboard...


Google MAP API v3: Center & Zoom on displayed markers

for center and auto zoom on display markers

// map: an instance of google.maps.Map object

// latlng_points_array: an array of google.maps.LatLng objects

var latlngbounds = new google.maps.LatLngBounds( );

    for ( var i = 0; i < latlng_points_array.length; i++ ) {
        latlngbounds.extend( latlng_points_array[i] );

map.fitBounds( latlngbounds );

Cleanest way to toggle a boolean variable in Java?


boolean result = isresult();
if (result) {
    result = false;
} else {
    result = true;


boolean result = isresult();
result ^= true;

Spark - repartition() vs coalesce()

What follows from the code and code docs is that coalesce(n) is the same as coalesce(n, shuffle = false) and repartition(n) is the same as coalesce(n, shuffle = true)

Thus, both coalesce and repartition can be used to increase number of partitions

With shuffle = true, you can actually coalesce to a larger number of partitions. This is useful if you have a small number of partitions, say 100, potentially with a few partitions being abnormally large.

Another important note to accentuate is that if you drastically decrease number of partitions you should consider using shuffled version of coalesce (same as repartition in that case). This will allow your computations be performed in parallel on parent partitions (multiple task).

However, if you're doing a drastic coalesce, e.g. to numPartitions = 1, this may result in your computation taking place on fewer nodes than you like (e.g. one node in the case of numPartitions = 1). To avoid this, you can pass shuffle = true. This will add a shuffle step, but means the current upstream partitions will be executed in parallel (per whatever the current partitioning is).

Please also refer to the related answer here

Programmatically open new pages on Tabs

It's up to the user whether they want to use new tabs or new windows, it isn't the business of the developer to modify this behaviour. I do not think you can do it.

Pet peeve of mine - I hate it when sites force me to open in a new window / tab - I am quite capable of making that decision for myself. Particularly when they do it in javascript - that is really unhelpful.

ModelState.IsValid == false, why?

As has just happened to me - this can also happen when you add a required property to your model without updating your form. In this case the ValidationSummary will not list the error message.

How to move from one fragment to another fragment on click of an ImageView in Android?

purple.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        Fragment fragment = new tasks();
        FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.replace(, fragment);

you write the above code...there we are replacing with our fragment. hope this helps you

Reference to non-static member function must be called

You may want to have a look at, especially [33.1] Is the type of "pointer-to-member-function" different from "pointer-to-function"?

How does one check if a table exists in an Android SQLite database?

Kotlin solution, based on what others wrote here:

    fun isTableExists(database: SQLiteDatabase, tableName: String): Boolean {
        database.rawQuery("select DISTINCT tbl_name from sqlite_master where tbl_name = '$tableName'", null)?.use {
            return it.count > 0
        } ?: return false

How to start a Process as administrator mode in C#

Here is an example of run process as administrator without Windows Prompt

  Process p = new Process();
  p.StartInfo.FileName = Server.MapPath("process.exe");
  p.StartInfo.Arguments = "";
  p.StartInfo.UseShellExecute = false;
  p.StartInfo.CreateNoWindow = true;
  p.StartInfo.RedirectStandardOutput = true;
  p.StartInfo.Verb = "runas";

Writing to a file in a for loop

The main problem was that you were opening/closing files repeatedly inside your loop.

Try this approach:

with open('new.txt') as text_file, open('xyz.txt', 'w') as myfile:  
    for line in text_file:
        var1, var2 = line.split(",");

We open both files at once and because we are using with they will be automatically closed when we are done (or an exception occurs). Previously your output file was repeatedly openend inside your loop.

We are also processing the file line-by-line, rather than reading all of it into memory at once (which can be a problem when you deal with really big files).

Note that write() doesn't append a newline ('\n') so you'll have to do that yourself if you need it (I replaced your writelines() with write() as you are writing a single item, not a list of items).

When opening a file for rread, the 'r' is optional since it's the default mode.

how to activate a textbox if I select an other option in drop down box

Below is the core JavaScript you need to write:

<script type="text/javascript">
function CheckColors(val){
 var element=document.getElementById('color');
 if(val=='pick a color'||val=='others')'block';

  <select name="color" onchange='CheckColors(this.value);'> 
    <option>pick a color</option>  
    <option value="red">RED</option>
    <option value="blue">BLUE</option>
    <option value="others">others</option>
<input type="text" name="color" id="color" style='display:none;'/>

pthread function from a class

C++ : How to pass class member function to pthread_create()?

typedef void * (*THREADFUNCPTR)(void *);

class C { 
   // ...
   void *print(void *) { cout << "Hello"; }

pthread_create(&threadId, NULL, (THREADFUNCPTR) &C::print, NULL);

How to convert column with string type to int form in pyspark data frame?

Another way to do it is using the StructField if you have multiple fields that needs to be modified.


from pyspark.sql.types import StructField,IntegerType, StructType,StringType



 |-- CLICK_FLG: string (nullable = true)
 |-- OPEN_FLG: string (nullable = true)
 |-- I1_GNDR_CODE: string (nullable = true)
 |-- TRW_INCOME_CD_V4: string (nullable = true)
 |-- ASIAN_CD: integer (nullable = true)
 |-- I1_INDIV_HHLD_STATUS_CODE: string (nullable = true)


 |-- CLICK_FLG: integer (nullable = true)
 |-- OPEN_FLG: integer (nullable = true)
 |-- I1_GNDR_CODE: string (nullable = true)
 |-- TRW_INCOME_CD_V4: string (nullable = true)
 |-- ASIAN_CD: integer (nullable = true)
 |-- I1_INDIV_HHLD_STATUS_CODE: integer (nullable = true)

This is slightly a long procedure to cast , but the advantage is that all the required fields can be done.

It is to be noted that if only the required fields are assigned the data type, then the resultant dataframe will contain only those fields which are changed.

How to return a struct from a function in C++?

Here is an edited version of your code which is based on ISO C++ and which works well with G++:

#include <string.h>
#include <iostream>
using namespace std;

#define NO_OF_TEST 1

struct studentType {
    string studentID;
    string firstName;
    string lastName;
    string subjectName;
    string courseGrade;
    int arrayMarks[4];
    double avgMarks;

studentType input() {
    studentType newStudent;
    cout << "\nPlease enter student information:\n";

    cout << "\nFirst Name: ";
    cin >> newStudent.firstName;

    cout << "\nLast Name: ";
    cin >> newStudent.lastName;

    cout << "\nStudent ID: ";
    cin >> newStudent.studentID;

    cout << "\nSubject Name: ";
    cin >> newStudent.subjectName;

    for (int i = 0; i < NO_OF_TEST; i++) {
        cout << "\nTest " << i+1 << " mark: ";
        cin >> newStudent.arrayMarks[i];

    return newStudent;

int main() {
    studentType s;
    s = input();

    cout <<"\n========"<< endl << "Collected the details of "
        << s.firstName << endl;

    return 0;

How to make the background DIV only transparent using CSS


        filter: alpha(opacity=80);
        opacity: 0.8;
        z-index: 10000;

Is there a kind of Firebug or JavaScript console debug for Android?

I also looked for a simple console replacement, just to dump text. So what I did was this function:

function remoteLog (arg) {
    var file = '/files/remoteLog.php';
    $.post(file, {text: arg});

The remote PHP file recorded all the output to a database in arg. It took me 5 minutes (OK, on the server side I used a simple logging library that records and displays text messages, but still...).

How to delete files/subfolders in a specific directory at the command prompt in Windows

rmdir is my all time favorite command for the job. It works for deleting huge files and folders with subfolders. A backup is not created, so make sure that you have copied your files safely before running this command.


This silently removes the folder and all files and subfolders.

How do you write multiline strings in Go?

You can write:

"line 1" +
"line 2" +
"line 3"

which is the same as:

"line 1line 2line 3"

Unlike using back ticks, it will preserve escape characters. Note that the "+" must be on the 'leading' line - for instance, the following will generate an error:

"line 1"
+"line 2"

What is the difference between a 'closure' and a 'lambda'?

It depends on whether a function uses external variable or not to perform operation.

External variables - variables defined outside the scope of a function.

  • Lambda expressions are stateless because It depends on parameters, internal variables or constants to perform operations.

    Function<Integer,Integer> lambda = t -> {
        int n = 2
        return t * n 
  • Closures hold state because it uses external variables (i.e. variable defined outside the scope of the function body) along with parameters and constants to perform operations.

    int n = 2
    Function<Integer,Integer> closure = t -> {
        return t * n 

When Java creates closure, it keeps the variable n with the function so it can be referenced when passed to other functions or used anywhere.

How to push to History in React Router v4?

Be careful that don't use [email protected] or [email protected] with [email protected]. URL will update after history.push or any other push to history instructions but navigation is not working with react-router. use npm install [email protected] to change the history version. see React router not working after upgrading to v 5.

I think this problem is happening when push to history happened. for example using <NavLink to="/apps"> facing a problem in NavLink.js that consume <RouterContext.Consumer>. context.location is changing to an object with action and location properties when the push to history occurs. So currentLocation.pathname is null to match the path.

Which comes first in a 2D array, rows or columns?

Instinctively one thinks geometrically: horizontal (X) axis and then vertical (Y) axis. This is not, however, the case with a 2D array, rows come first and then columns.

Consider the following analogy: in geometry one walks to the ladder (X axis) and climbs it (Y axis). Conversely, in Java one descends the ladder (rows) and walks away (columns).

Excel CSV. file with more than 1,048,576 rows of data

First you want to change the file format from csv to txt. That is simple to do, just edit the file name and change csv to txt. (Windows will give you warning about possibly corrupting the data, but it is fine, just click ok). Then make a copy of the txt file so that now you have two files both with 2 millions rows of data. Then open up the first txt file and delete the second million rows and save the file. Then open the second txt file and delete the first million rows and save the file. Now change the two files back to csv the same way you changed them to txt originally.

How to load a controller from another controller in codeigniter?

you cannot call a controller method from another controller directly

my solution is to use inheritances and extend your controller from the library controller

class Controller1 extends CI_Controller {

    public function index() {
        // some codes here

    public function methodA(){
        // code here

in your controller we call it Mycontoller it will extends Controller1

include_once (dirname(__FILE__) . "/controller1.php");

class Mycontroller extends Controller1 {

    public function __construct() {

    public function methodB(){
        // codes....

and you can call methodA from mycontroller

this solution worked for me

How to prevent a double-click using jQuery?

just put this method in your forms then it will handle double-click or more clicks in once. once request send it will not allow sending again and again request.

<script type="text/javascript">
            $("form").submit(function() {
                $(this).submit(function() {
                    return false;
                return true;

it will help you for sure.

Get IPv4 addresses from Dns.GetHostEntry()


lblIP.Text = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName).AddressList(0).ToString()


lblIP.Text = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName).AddressList(1).ToString()

C99 stdint.h header and MS Visual Studio

Another portable solution:

POSH: The Portable Open Source Harness

"POSH is a simple, portable, easy-to-use, easy-to-integrate, flexible, open source "harness" designed to make writing cross-platform libraries and applications significantly less tedious to create and port."

as described and used in the book: Write portable code: an introduction to developing software for multiple platforms By Brian Hook


alternatives to REPLACE on a text or ntext datatype

Assuming SQL Server 2000, the following StackOverflow question should address your problem.

If using SQL Server 2005/2008, you can use the following code (taken from here):

select cast(replace(cast(myntext as nvarchar(max)),'find','replace') as ntext)
from myntexttable

Shell Script: Execute a python program from within a shell script

Save the following program as

print('Hello World')

Then in the terminal type:

chmod +x

How does Trello access the user's clipboard?

Something very similar can be seen on when you shorten the URL.

There is a readonly input element that gets programmatically focused, with tooltip press CTRL-C to copy.

When you hit that shortcut, the input content effectively gets into the clipboard. Really nice :)

Mysql SELECT CASE WHEN something then return field

You are mixing the 2 different CASE syntaxes inappropriately.

Use this style (Searched)

  WHEN u.nnmu ='0' THEN mu.naziv_mesta
  WHEN u.nnmu ='1' THEN m.naziv_mesta
 END as mesto_utovara,

Or this style (Simple)

  CASE u.nnmu 
  WHEN '0' THEN mu.naziv_mesta
  WHEN '1' THEN m.naziv_mesta
 END as mesto_utovara,

Not This (Simple but with boolean search predicates)

  CASE u.nnmu 
  WHEN u.nnmu ='0' THEN mu.naziv_mesta
  WHEN u.nnmu ='1' THEN m.naziv_mesta
 END as mesto_utovara,

In MySQL this will end up testing whether u.nnmu is equal to the value of the boolean expression u.nnmu ='0' itself. Regardless of whether u.nnmu is 1 or 0 the result of the case expression itself will be 1

For example if nmu = '0' then (nnmu ='0') evaluates as true (1) and (nnmu ='1') evaluates as false (0). Substituting these into the case expression gives

  WHEN 1 THEN '0'
  WHEN 0 THEN '1'
 END as mesto_utovara

if nmu = '1' then (nnmu ='0') evaluates as false (0) and (nnmu ='1') evaluates as true (1). Substituting these into the case expression gives

  WHEN 0 THEN '0'
  WHEN 1 THEN '1'
 END as mesto_utovara

Padding a table row

You could simply add this style to the table.

table {
    border-spacing: 15px;

Inner Joining three tables

select *
    tableA a
        inner join
    tableB b
        on a.common = b.common
        inner join 
    TableC c
        on b.common = c.common

How to add many functions in ONE ng-click?

Try this:

  • Make a collection of functions
  • Make a function that loops through and executes all the functions in the collection.
  • Add the function to the html
array = [
    function() {},
    function() {},
    function() {}

function loop() {
    array.forEach(item) {

ng - click = "loop()"

How to change content on hover

<span class="label"></span>

How to redirect output to a file and stdout

The command you want is named tee:

foo | tee output.file

For example, if you only care about stdout:

ls -a | tee output.file

If you want to include stderr, do:

program [arguments...] 2>&1 | tee outfile

2>&1 redirects channel 2 (stderr/standard error) into channel 1 (stdout/standard output), such that both is written as stdout. It is also directed to the given output file as of the tee command.

Furthermore, if you want to append to the log file, use tee -a as:

program [arguments...] 2>&1 | tee -a outfile

How to request a random row in SQL?


takes 7.4 milliseconds

WHERE num_value >= RAND() * (SELECT MAX(num_value) FROM table)

takes 0.0065 milliseconds!

I will definitely go with latter method.

Getting the size of an array in an object

Javascript arrays have a length property. Use it like this:


Compile throws a "User-defined type not defined" error but does not go to the offending line of code

Possible solution, you are trying to work with Powerpoint via Excel VBA and you didn't activate Powerpoint Object Library first.

To do this, in the VBA editor top menu select Tools, References, then scroll down to click the library called Microsoft Powerpoint xx.x Object Library. Office 2007 is library 12, each Office version has a different library. FYI, I've experienced some odd errors and file corruption when I activate the 2007 library but someone tries to open and run this macro using Excel 2003. The old version of Excel doesn't recognize the newer library, which seems to cause problems.

How to export data as CSV format from SQL Server using sqlcmd?

Since following 2 reasons, you should run my solution in CMD:

  1. There may be double quotes in the query
  2. Login username & password is sometimes necessary to query a remote SQL Server instance

    sqlcmd -U [your_User]  -P[your_password] -S [your_remote_Server] -d [your_databasename]  -i "query.txt" -o "output.csv" -s"," -w 700

Can we use JSch for SSH key-based communication?

It is possible. Have a look at JSch.addIdentity(...)

This allows you to use key either as byte array or to read it from file.

import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;

public class UserAuthPubKey {
    public static void main(String[] arg) {
        try {
            JSch jsch = new JSch();

            String user = "tjill";
            String host = "";
            int port = 10022;
            String privateKey = ".ssh/id_rsa";

            System.out.println("identity added ");

            Session session = jsch.getSession(user, host, port);
            System.out.println("session created.");

            // disabling StrictHostKeyChecking may help to make connection but makes it insecure
            // see
            // java.util.Properties config = new java.util.Properties();
            // config.put("StrictHostKeyChecking", "no");
            // session.setConfig(config);

            System.out.println("session connected.....");

            Channel channel = session.openChannel("sftp");
            System.out.println("shell channel connected....");

            ChannelSftp c = (ChannelSftp) channel;

            String fileName = "test.txt";
            c.put(fileName, "./in/");

        } catch (Exception e) {

Make a table fill the entire window

This works fine for me:

<style type="text/css">_x000D_
#table {_x000D_
 position: absolute;_x000D_
 top: 0;_x000D_
 bottom: 0;_x000D_
 left: 0;_x000D_
 right: 0;_x000D_
 height: 100%;_x000D_
 width: 100%;_x000D_

For me, just changing Height and Width to 100% doesn’t do it for me, and neither do setting left, right, top and bottom to 0, but using them both together will do the trick.

How do I download a tarball from GitHub using cURL?

The modernized way of doing this is:

curl -sL | tar xz

Replace user-or-org, repo, and sha1-or-ref accordingly.

If you want a zip file instead of a tarball, specify .zip instead of .tar.gz suffix.

You can also retrieve the archive of a private repo, by specifying -u token:x-oauth-basic option to curl. Replace token with a personal access token.

How do I pass named parameters with Invoke-Command?

I suspect its a new feature since this post was created - pass parameters to the script block using $Using:var. Then its a simple mater to pass parameters provided the script is already on the machine or in a known network location relative to the machine

Taking the main example it would be:

icm -cn $Env:ComputerName { 
    C:\Scripts\ArchiveEventLogs\ver5\ArchiveEventLogs.ps1 -one "uno" -two "dos" -Debug -Clear $Using:Clear

Calculating how many minutes there are between two times

Try this

DateTime startTime = varValue
DateTime endTime = varTime

TimeSpan span = endTime.Subtract ( startTime );
Console.WriteLine( "Time Difference (minutes): " + span.TotalMinutes );

Edit: If are you trying 'span.Minutes', this will return only the minutes of timespan [0~59], to return sum of all minutes from this interval, just use 'span.TotalMinutes'.

How do you access the matched groups in a JavaScript regular expression?

I you are like me and wish regex would return an Object like this:

    match: '...',
    matchAtIndex: 0,
    capturedGroups: [ '...', '...' ]

then snip the function from below

 * @param {string | number} input_x000D_
 *          The input string to match_x000D_
 * @param {regex | string}  expression_x000D_
 *          Regular expression _x000D_
 * @param {string} flags_x000D_
 *          Optional Flags_x000D_
 * _x000D_
 * @returns {array}_x000D_
 * [{_x000D_
    match: '...',_x000D_
    matchAtIndex: 0,_x000D_
    capturedGroups: [ '...', '...' ]_x000D_
  }]     _x000D_
function regexMatch(input, expression, flags = "g") {_x000D_
  let regex = expression instanceof RegExp ? expression : new RegExp(expression, flags)_x000D_
  let matches = input.matchAll(regex)_x000D_
  matches = [...matches]_x000D_
  return => {_x000D_
    return {_x000D_
      match: item[0],_x000D_
      matchAtIndex: item.index,_x000D_
      capturedGroups: item.length > 1 ? item.slice(1) : undefined_x000D_
let input = "key1:value1, key2:value2 "_x000D_
let regex = /(\w+):(\w+)/g_x000D_
let matches = regexMatch(input, regex)_x000D_

Oracle insert from select into table with more columns

Put 0 as default in SQL or add 0 into your area of table

how to print an exception using logger?

You should probably clarify which logger are you using.

org.apache.commons.logging.Log interface has method void error(Object message, Throwable t) (and method void info(Object message, Throwable t)), which logs the stack trace together with your custom message. Log4J implementation has this method too.

So, probably you need to write:

logger.error("BOOM!", e);

If you need to log it with INFO level (though, it might be a strange use case), then:"Just a stack trace, nothing to worry about", e);

Hope it helps.

C++ error: "Array must be initialized with a brace enclosed initializer"

You cannot initialize an array to '0' like that

int cipher[Array_size][Array_size]=0;

You can either initialize all the values in the array as you declare it like this:

// When using different values
int a[3] = {10,20,30};

// When using the same value for all members
int a[3] = {0};

// When using same value for all members in a 2D array
int a[Array_size][Array_size] = { { 0 } };

Or you need to initialize the values after declaration. If you want to initialize all values to 0 for example, you could do something like:

for (int i = 0; i < Array_size; i++ ) {
    a[i] = 0;

How can I get the MAC and the IP address of a connected client in PHP?

Getting MAC Address Using PHP: (Tested in Ubuntu 18.04) - 2020 Update

Here's the Code:

    $mac = shell_exec("ip link | awk '{print $2}'");
    preg_match_all('/([a-z0-9]+):\s+((?:[0-9a-f]{2}:){5}[0-9a-f]{2})/i', $mac, $matches);
    $output = array_combine($matches[1], $matches[2]);
    $mac_address_values =  json_encode($output, JSON_PRETTY_PRINT);   
    echo $mac_address_values


    "lo": "00:00:00:00:00:00",
    "enp0s25": "00:21:cc:d4:2a:23",
    "wlp3s0": "84:3a:4b:03:3c:3a",
    "wwp0s20u4": "7a:e3:2a:de:66:09"

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.

Non-invocable member cannot be used like a method?

Where you've written "OffenceBox.Text()", you need to replace this with "OffenceBox.Text". It's a property, not a method - the clue's in the error!

How do I find a stored procedure containing <text>?

I took Kashif's answer and union'd all of them together. Strangely, sometimes, I found results in one of the selects but not the other. So to be safe, I run all 3 when I'm looking for something. Hope this helps:

DECLARE @SearchText varchar(1000) = 'mytext';

        WHERE ROUTINE_DEFINITION LIKE '%' + @SearchText + '%' 
        WHERE [text] LIKE '%' + @SearchText + '%' 
        AND OBJECTPROPERTY(id, 'IsProcedure') = 1 
    (SELECT OBJECT_NAME(object_id) SPName
        FROM sys.sql_modules
        WHERE OBJECTPROPERTY(object_id, 'IsProcedure') = 1
        AND definition LIKE '%' + @SearchText + '%')
) AS T

Example of a strong and weak entity types

A weak entity is the entity which can't be fully identified by its own attributes and takes the foreign key as an attribute (generally it takes the primary key of the entity it is related to) in conjunction.


The existence of rooms is entirely dependent on the existence of a hotel. So room can be seen as the weak entity of the hotel.
Another example is the
bank account of a particular bank has no existence if the bank doesn't exist anymore.

Access camera from a browser

Video Tutorial: Accessing the Camera with HTML5 & appMobi API will be helpful for you.

Also, you may try the getUserMedia method (supported by Opera 12)

enter image description here

Installing Java 7 (Oracle) in Debian via apt-get

Managed to get answer after do some google..

echo "deb precise main" | tee -a /etc/apt/sources.list
echo "deb-src precise main" | tee -a /etc/apt/sources.list
apt-key adv --keyserver hkp:// --recv-keys EEA14886
apt-get update
# Java 7
apt-get install oracle-java7-installer
# For Java 8 command is:
apt-get install oracle-java8-installer

Composer Warning: openssl extension is missing. How to enable in WAMP

Yes, you must have to open php.ini and remove the semicolon to:


remove the ";" like this and it will work.


Happy Coding.

What is time(NULL) in C?

You have to refer to the documentation for ctime. time is a function that takes one parameter of type time_t * (a pointer to a time_t object) and assigns to it the current time. Instead of passing this pointer, you can also pass NULL and then use the returned time_t value instead.

How can I make Flexbox children 100% height of their parent?

If I understand correctly, you want flex-2-child to fill the height and width of its parent, so that the red area is fully covered by the green?

If so, you just need to set flex-2 to use Flexbox:

.flex-2 {
    display: flex;

Then tell flex-2-child to become flexible:

.flex-2-child {
    flex: 1;


The reason is that flex-2-child is not a Flexbox item, but its parent is.

select the TOP N rows from a table

you can also check this link

SELECT * FROM master_question WHERE 1 ORDER BY question_id ASC LIMIT 20

for more detail click here

Ordering by the order of values in a SQL IN() clause

Give this a shot:

SELECT name, description, ...
    (SELECT id FROM table1 WHERE...)
    (SELECT display_order FROM table1 WHERE...),
    (SELECT name FROM table1 WHERE...)

The WHEREs will probably take a little tweaking to get the correlated subqueries working properly, but the basic principle should be sound.

What's the fastest way to loop through an array in JavaScript?

After performing this test with most modern browsers:

Currently, the fastest form of loop (and in my opinion the most syntactically obvious).

A standard for-loop with length caching

    var i = 0, len = myArray.length;
    while (i < len) {
        // your code

I would say, this is definitely a case where I applaud JavaScript engine developers. A runtime should be optimized for clarity, not cleverness.

How to check if a string is a valid JSON string in JavaScript without using Try/Catch

If you're dealing with a response from an AJAX (or XMLHttpRequest) call, what worked for me is to check the response content type and parse or not the content accordingly.

Convert number of minutes into hours & minutes using PHP

$hours = floor($final_time_saving / 60);
$minutes = $final_time_saving % 60;

How to insert a large block of HTML in JavaScript?

Template literals may solve your issue as it will allow writing multi-line strings and string interpolation features. You can use variables or expression inside string (as given below). It's easy to insert bulk html in a reader friendly way.

I have modified the example given in question and please see it below. I am not sure how much browser compatible Template literals are. Please read about Template literals here.

var a = 1, b = 2;_x000D_
var div = document.createElement('div');_x000D_
div.setAttribute('class', 'post block bc2');_x000D_
div.innerHTML = `_x000D_
    <div class="parent">_x000D_
        <div class="child">${a}</div>_x000D_
        <div class="child">+</div>_x000D_
        <div class="child">${b}</div>_x000D_
        <div class="child">=</div>_x000D_
        <div class="child">${a + b}</div>_x000D_
.parent {_x000D_
  background-color: blue;_x000D_
  display: flex;_x000D_
  justify-content: center;_x000D_
.post div {_x000D_
  color: white;_x000D_
  font-size: 2.5em;_x000D_
  padding: 20px;_x000D_
<div id="posts"></div>

changing iframe source with jquery

Should work.

Here's a working example:


function loadIframe(iframeName, url) {
    var $iframe = $('#' + iframeName);
    if ($iframe.length) {
        return false;
    return true;

Remove local git tags that are no longer on the remote repository

TortoiseGit can compare tags now.

Left log is on remote, right is at local.

enter image description here

Using the Compare tags feature of Sync dialog:

enter image description here

Also see TortoiseGit issue 2973

In SQL Server, how do I generate a CREATE TABLE statement for a given table?

I include definitions for computed columns

    select 'CREATE TABLE [' + + '] (' + o.list + ')' + CASE WHEN tc.Constraint_Name IS NULL THEN '' ELSE 'ALTER TABLE ' + so.Name + ' ADD CONSTRAINT ' + tc.Constraint_Name  + ' PRIMARY KEY ' + ' (' + LEFT(j.List, Len(j.List)-1) + ')' END, name
from    sysobjects so
cross apply

case when comps.definition is not null then '  ['+column_name+'] AS ' + comps.definition 
        '  ['+column_name+'] ' + data_type + 
        when data_type like '%text' or data_type in ('image', 'sql_variant' ,'xml')
            then ''
        when data_type in ('float')
            then '(' + cast(coalesce(numeric_precision, 18) as varchar(11)) + ')'
        when data_type in ('datetime2', 'datetimeoffset', 'time')
            then '(' + cast(coalesce(datetime_precision, 7) as varchar(11)) + ')'
        when data_type in ('decimal', 'numeric')
            then '(' + cast(coalesce(numeric_precision, 18) as varchar(11)) + ',' + cast(coalesce(numeric_scale, 0) as varchar(11)) + ')'
        when (data_type like '%binary' or data_type like '%char') and character_maximum_length = -1
            then '(max)'
        when character_maximum_length is not null
            then '(' + cast(character_maximum_length as varchar(11)) + ')'
        else ''
        end + ' ' +
        case when exists ( 
        select id from syscolumns
        where object_name(id)
        and name=column_name
        and columnproperty(id,name,'IsIdentity') = 1 
        ) then
        'IDENTITY(' + 
        cast(ident_seed( as varchar) + ',' + 
        cast(ident_incr( as varchar) + ')'
        else ''
        end + ' ' +
         (case when information_schema.columns.IS_NULLABLE = 'No' then 'NOT ' else '' end ) + 'NULL ' + 
          case when information_schema.columns.COLUMN_DEFAULT IS NOT NULL THEN 'DEFAULT '+ information_schema.columns.COLUMN_DEFAULT ELSE '' END 
end + ', ' 

     from information_schema.columns 
     left join sys.computed_columns comps 
     on OBJECT_ID(information_schema.columns.TABLE_NAME)=comps.object_id and

     where table_name =
     order by ordinal_position
    FOR XML PATH('')) o (list)
left join
    information_schema.table_constraints tc
on  tc.Table_name       = so.Name
AND tc.Constraint_Type  = 'PRIMARY KEY'
cross apply
    (select '[' + Column_Name + '], '
     FROM   information_schema.key_column_usage kcu
     WHERE  kcu.Constraint_Name = tc.Constraint_Name
     FOR XML PATH('')) j (list)
where   xtype = 'U'
AND name    NOT IN ('dtproperties')

How can I search Git branches for a file or directory?

You could use gitk --all and search for commits "touching paths" and the pathname you are interested in.

Undo git pull, how to bring repos to old state

Try run

git reset --keep HEAD@{1}

Java format yyyy-MM-dd'T'HH:mm:ss.SSSz to yyyy-mm-dd HH:mm:ss

I have a case where I am transforming a legacy DB2 z/os database timestamp (formatted as: "yyyy-MM-dd'T'HH:mm:ss.SSSZ") into a SqlServer 2016 datetime2 (formatted as: "yyyy-MM-dd HH:mm:ss.SSS) field that is handled by our Spring/Hibernate Entity Manager instance (in this case, the OldRevision Table). In the Class, I define the date as the java.util type, and write the setter and getter in the normal way. Then, When handling the data, the code I have handling the data related to this question looks like this:

OldRevision revision = new OldRevision();
String oldRevisionDateString= oldRevisionData.getString("originalRevisionDate", "");
Date oldDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss.SSSZ");
SimpleDateFormat newDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
Date finalFormattedDate= newDateFormat.parse(newDateFormat.format(oldDateFormat));

A simpler way to do the same case is:

SimpleDateFormat newDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
                new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss.SSSZ")
                        .parse(rs.getString("originalRevisionDate", "")))));

How to redirect on another page and pass parameter in url from table?

Set the user name as data-username attribute to the button and also a class:


<input type="button" name="theButton" value="Detail" class="btn" data-username="{{result['username']}}" />


$(document).on('click', '.btn', function() {

    var name = $(this).data('username');        
    if (name != undefined && name != null) {
        window.location = '/player_detail?username=' + name;


Also, you can simply check for undefined && null using:

$(document).on('click', '.btn', function() {

    var name = $(this).data('username');        
    if (name) {
        window.location = '/player_detail?username=' + name;

As, mentioned in this answer

if (name) {            

will evaluate to true if value is not:

  • null
  • undefined
  • NaN
  • empty string ("")
  • 0
  • false

The above list represents all possible falsy values in ECMA/Javascript.

How to remove leading zeros using C#

return numberString.TrimStart('0');

Gray out image with CSS?

If you don't mind using a bit of JavaScript, jQuery's fadeTo() works nicely in every browser I've tried.

jQuery(selector).fadeTo(speed, opacity);

How to automatically reload a page after a given period of inactivity

Yes dear,then you have to use Ajax technology. to changes contents of particular html tag:

        <script src=""></script>
        <title>Ajax Page</title>
        setInterval(function () { autoloadpage(); }, 30000); // it will call the function autoload() after each 30 seconds. 
        function autoloadpage() {
                url: "URL of the destination page",
                type: "POST",
                success: function(data) {
                    $("div#wrapper").html(data); // here the wrapper is main div
    <div id="wrapper">
    contents will be changed automatically. 

MVC which submit button has been pressed

This post is not going to answer to Coppermill, because he have been answered long time ago. My post will be helpful for who will seeking for solution like this. First of all , I have to say " WDuffy's solution is totally correct" and it works fine, but my solution (not actually mine) will be used in other elements and it makes the presentation layer more independent from controller (because your controller depend on "value" which is used for showing label of the button, this feature is important for other languages.).

Here is my solution, give them different names:

<input type="submit" name="buttonSave" value="Save"/>
<input type="submit" name="buttonProcess" value="Process"/>
<input type="submit" name="buttonCancel" value="Cancel"/>

And you must specify the names of buttons as arguments in the action like below:

public ActionResult Register(string buttonSave, string buttonProcess, string buttonCancel)
    if (buttonSave!= null)
        //save is pressed
    if (buttonProcess!= null)
        //Process is pressed
    if (buttonCancel!= null)
        //Cancel is pressed

when user submits the page using one of the buttons, only one of the arguments will have value. I guess this will be helpful for others.


This answer is quite old and I actually reconsider my opinion . maybe above solution is good for situation which passing parameter to model's properties. don't bother yourselves and take best solution for your project.

Activity transition in Android

An even easy way to do it is:

  1. Create an animation style into your styles.xml file
<style name="WindowAnimationTransition">
    <item name="android:windowEnterAnimation">@android:anim/fade_in</item>
    <item name="android:windowExitAnimation">@android:anim/fade_out</item>
  1. Add this style to your app theme
<style name="AppBaseTheme" parent="Theme.Material.Light.DarkActionBar">
      <item name="android:windowAnimationStyle">@style/WindowAnimationTransition</item>

That's it :)

MySQL Error: : 'Access denied for user 'root'@'localhost'

None of the above answers helped me with this problem, so here's the solution I found.

The relevant part:

In Ubuntu systems running MySQL 5.7 (and later versions), the root MySQL user is set to authenticate using the auth_socket plugin by default rather than with a password. This allows for some greater security and usability in many cases, but it can also complicate things when you need to allow an external program (e.g., phpMyAdmin) to access the user.

In order to use a password to connect to MySQL as root, you will need to switch its authentication method from auth_socket to mysql_native_password. To do this, open up the MySQL prompt from your terminal:

sudo mysql

Next, check which authentication method each of your MySQL user accounts use with the following command:

SELECT user,authentication_string,plugin,host FROM mysql.user;


| user             | authentication_string                     | plugin                | host      |
| root             |                                           | auth_socket           | localhost |
| mysql.session    | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password | localhost |
| mysql.sys        | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password | localhost |
| debian-sys-maint | *CC744277A401A7D25BE1CA89AFF17BF607F876FF | mysql_native_password | localhost |
4 rows in set (0.00 sec)

In this example, you can see that the root user does in fact authenticate using the auth_socket plugin. To configure the root account to authenticate with a password, run the following ALTER USER command. Be sure to change password to a strong password of your choosing, and note that this command will change the root password you set in Step 2:

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';

Then, run FLUSH PRIVILEGES which tells the server to reload the grant tables and put your new changes into effect:


Check the authentication methods employed by each of your users again to confirm that root no longer authenticates using the auth_socket plugin:

SELECT user,authentication_string,plugin,host FROM mysql.user;


| user             | authentication_string                     | plugin                | host      |
| root             | *3636DACC8616D997782ADD0839F92C1571D6D78F | mysql_native_password | localhost |
| mysql.session    | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password | localhost |
| mysql.sys        | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password | localhost |
| debian-sys-maint | *CC744277A401A7D25BE1CA89AFF17BF607F876FF | mysql_native_password | localhost |
4 rows in set (0.00 sec)

You can see in this example output that the root MySQL user now authenticates using a password. Once you confirm this on your own server, you can exit the MySQL shell:


What is an opaque response, and what purpose does it serve?

Consider the case in which a service worker acts as an agnostic cache. Your only goal is serve the same resources that you would get from the network, but faster. Of course you can't ensure all the resources will be part of your origin (consider libraries served from CDNs, for instance). As the service worker has the potential of altering network responses, you need to guarantee you are not interested in the contents of the response, nor on its headers, nor even on the result. You're only interested on the response as a black box to possibly cache it and serve it faster.

This is what { mode: 'no-cors' } was made for.

How can I open a popup window with a fixed size using the HREF tag?

Plain HTML does not support this. You'll need to use some JavaScript code.

Also, note that large parts of the world are using a popup blocker nowadays. You may want to reconsider your design!

How to Detect cause of 503 Service Temporarily Unavailable error and handle it?

There is of course some apache log files. Search in your apache configuration files for 'Log' keyword, you'll certainly find plenty of them. Depending on your OS and installation places may vary (in a Typical Linux server it would be /var/log/apache2/[access|error].log).

Having a 503 error in Apache usually means the proxied page/service is not available. I assume you're using tomcat and that means tomcat is either not responding to apache (timeout?) or not even available (down? crashed?). So chances are that it's a configuration error in the way to connect apache and tomcat or an application inside tomcat that is not even sending a response for apache.

Sometimes, in production servers, it can as well be that you get too much traffic for the tomcat server, apache handle more request than the proxyied service (tomcat) can accept so the backend became unavailable.

Cassandra cqlsh - connection refused

Had same problem recently after downgrade from Cassandra 3.0 to Cassandra 2.2 on ArchLinux.

Unlike above solutions my problem wasn't in .cassandra, but version 3.0 left its configuration in /var/lib/cassandra directory.

Following commands solved my problem:

sudo rm -R /var/lib/cassandra
sudo rm -R /var/log/cassandra
sudo rm -R /usr/share/cassandra

Then i installed cassandra and everything worked again :)

PersistenceContext EntityManager injection NullPointerException

An entity manager can only be injected in classes running inside a transaction. In other words, it can only be injected in a EJB. Other classe must use an EntityManagerFactory to create and destroy an EntityManager.

Since your TestService is not an EJB, the annotation @PersistenceContext is simply ignored. Not only that, in JavaEE 5, it's not possible to inject an EntityManager nor an EntityManagerFactory in a JAX-RS Service. You have to go with a JavaEE 6 server (JBoss 6, Glassfish 3, etc).

Here's an example of injecting an EntityManagerFactory:

package com.test.service;

import java.util.*;
import javax.persistence.*;

public class TestService {

    @PersistenceUnit(unitName = "test")
    private EntityManagerFactory entityManagerFactory;

    public List get() {
        EntityManager entityManager = entityManagerFactory.createEntityManager();
        try {
            return entityManager.createQuery("from TestEntity").getResultList();
        } finally {

The easiest way to go here is to declare your service as a EJB 3.1, assuming you're using a JavaEE 6 server.

Related question: Inject an EJB into JAX-RS (RESTful service)

How to use a SQL SELECT statement with Access VBA

Access 2007 can lose the CurrentDb: see, so in the event of getting "Object Invalid or no longer set" with the examples, use:

Dim db as Database
Dim rs As DAO.Recordset
Set db = CurrentDB
Set rs = db.OpenRecordset("SELECT * FROM myTable")

android pinch zoom

In honeycomb, API level 11, it is possible, We can use setScalaX and setScaleY with pivot point
I have explained it here
Zooming a view completely
Pinch Zoom to view completely

Postman Chrome: What is the difference between form-data, x-www-form-urlencoded and raw


Note. Please consult RFC2388 for additional information about file uploads, including backwards compatibility issues, the relationship between "multipart/form-data" and other content types, performance issues, etc.

Please consult the appendix for information about security issues for forms.

The content type "application/x-www-form-urlencoded" is inefficient for sending large quantities of binary data or text containing non-ASCII characters. The content type "multipart/form-data" should be used for submitting forms that contain files, non-ASCII data, and binary data.

The content type "multipart/form-data" follows the rules of all multipart MIME data streams as outlined in RFC2045. The definition of "multipart/form-data" is available at the [IANA] registry.

A "multipart/form-data" message contains a series of parts, each representing a successful control. The parts are sent to the processing agent in the same order the corresponding controls appear in the document stream. Part boundaries should not occur in any of the data; how this is done lies outside the scope of this specification.

As with all multipart MIME types, each part has an optional "Content-Type" header that defaults to "text/plain". User agents should supply the "Content-Type" header, accompanied by a "charset" parameter.


This is the default content type. Forms submitted with this content type must be encoded as follows:

Control names and values are escaped. Space characters are replaced by +', and then reserved characters are escaped as described in [RFC1738], section 2.2: Non-alphanumeric characters are replaced by%HH', a percent sign and two hexadecimal digits representing the ASCII code of the character. Line breaks are represented as "CR LF" pairs (i.e., %0D%0A'). The control names/values are listed in the order they appear in the document. The name is separated from the value by=' and name/value pairs are separated from each other by `&'.

application/x-www-form-urlencoded the body of the HTTP message sent to the server is essentially one giant query string -- name/value pairs are separated by the ampersand (&), and names are separated from values by the equals symbol (=). An example of this would be:


The content type "application/x-www-form-urlencoded" is inefficient for sending large quantities of binary data or text containing non-ASCII characters. The content type "multipart/form-data" should be used for submitting forms that contain files, non-ASCII data, and binary data.

Could not resolve '...' from state ''

I've just had this same issue with Ionic.

It turns out nothing was wrong with my code, I simply had to quit the ionic serve session and run ionic serve again.

After going back into the app, my states worked fine.

I would also suggest pressing save on your app.js file a few times if you are running gulp, to make sure everything gets re-compiled.

How do I specify different layouts for portrait and landscape orientations?

For Mouse lovers! I say right click on resources folder and Add new resource file, and from Available qualifiers select the orientation :

enter image description here

But still you can do it manually by say, adding the sub-folder "layout-land" to


since then any layout.xml file under this sub-folder will only work for landscape mode automatically.

Use "layout-port" for portrait mode.

Auto-scaling input[type=text] to width of value?


I have seen several ways to do this but calculating the width of fonts isn't always 100% accurate, it's just an estimate.

I managed to create a pixel perfect way of adjusting the input width by having a hidden placeholder to measure from.

jQuery (Recommended)

}).on('input', function () {_x000D_
<script src=""></script>_x000D_
<p>Lorem ipsum _x000D_
  <span id="hide"></span><input id="txt" type="text" value="type here ...">_x000D_
  egestas arcu._x000D_

Pure JavaScript

I was unable to determine how jQuery calculates the width of hidden elements so a slight tweak to css was required to accomodate this solution.

var hide = document.getElementById('hide');_x000D_
var txt = document.getElementById('txt');_x000D_
txt.addEventListener("input", resize);_x000D_
function resize() {_x000D_
  hide.textContent = txt.value;_x000D_ = hide.offsetWidth + "px";_x000D_
#hide {_x000D_
  font: inherit;_x000D_
  margin: 0;_x000D_
  padding: 0;_x000D_
#txt {_x000D_
  border: none;_x000D_
  color: #888;_x000D_
  min-width: 10px;_x000D_
#hide {_x000D_
  position: absolute;_x000D_
  height: 0;_x000D_
  overflow: hidden;_x000D_
  white-space: pre;_x000D_
<p>Lorem ipsum_x000D_
  <span id="hide"></span><input id="txt" type="text" value="type here ..."> egestas arcu._x000D_

Setting up a cron job in Windows

If you don't want to use Scheduled Tasks you can use the Windows Subsystem for Linux which will allow you to use cron jobs like on Linux.

To make sure cron is actually running you can type service cron status from within the Linux terminal. If it isn't currently running then type service cron start and you should be good to go.

ImportError: cannot import name

This can also happen if you've been working on your scripts and functions and have been moving them around (i.e. changed the location of the definition) which could have accidentally created a looping reference.

You may find that the situation is solved if you just reset the iPython kernal to clear any old assignments:


or menu->restart terminal

JavaScript: Get image dimensions

This uses the function and waits for it to complete.

function getMeta(url){
    var r = $.Deferred();

  $('<img/>').attr('src', url).load(function(){
     var s = {w:this.width, h:this.height};
  return r;

    alert(test.w + ' ' + test.h);

Execute a batch file on a remote PC using a batch file on local PC

You can use WMIC or SCHTASKS (which means no third party software is needed):


SCHTASKS /s remote_machine /U username /P password /create /tn "On demand demo" /tr "C:\some.bat" /sc ONCE /sd 01/01/1910 /st 00:00
SCHTASKS /s remote_machine /U username /P password /run /TN "On demand demo" 

2) WMIC (wmic will return the pid of the started process)

WMIC /NODE:"remote_machine" /user user /password password process call create "c:\some.bat","c:\exec_dir"

Validate fields after user has left a field

If you use bootstrap 3 and lesscss you can enable on blur validation with the following less snippet:

:focus ~ .form-control-feedback.glyphicon-ok {

:focus ~ .form-control-feedback.glyphicon-remove {

.has-feedback > :focus {
  & {

How can I search (case-insensitive) in a column using LIKE wildcard?

SELECT name 
       FROM gallery 
       WHERE CONVERT(name USING utf8) LIKE _utf8 '%$q%' 
       GROUP BY name COLLATE utf8_general_ci LIMIT 5 

Keeping ASP.NET Session Open / Alive

Do you really need to keep the session (do you have data in it?) or is it enough to fake this by reinstantiating the session when a request comes in? If the first, use the method above. If the second, try something like using the Session_End event handler.

If you have Forms Authentication, then you get something in the Global.asax.cs like

FormsAuthenticationTicket ticket = FormsAuthentication.Decrypt(formsCookie.Value);
if (ticket.Expired)
{   ...
    // renew ticket if old
    ticket = FormsAuthentication.RenewTicketIfOld(ticket);

And you set the ticket lifetime much longer than the session lifetime. If you're not authenticating, or using a different authentication method, there are similar tricks. Microsoft TFS web interface and SharePoint seem to use these - the give away is that if you click a link on a stale page, you get authentication prompts in the popup window, but if you just use a command, it works.

How do I add a bullet symbol in TextView?

Copy paste: •. I've done it with other weird characters, such as ? and ?.

Edit: here's an example. The two Buttons at the bottom have android:text="?" and "?".

What happened to the .pull-left and .pull-right classes in Bootstrap 4?

bootstrap-4 add class float-left or right for floating

HTTP POST and GET using cURL in Linux

*nix provides a nice little command which makes our lives a lot easier.


with JSON:

curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://hostname/resource

with XML:

curl -H "Accept: application/xml" -H "Content-Type: application/xml" -X GET http://hostname/resource


For posting data:

curl --data "param1=value1&param2=value2" http://hostname/resource

For file upload:

curl --form "[email protected]" http://hostname/resource

RESTful HTTP Post:

curl -X POST -d @filename http://hostname/resource

For logging into a site (auth):

curl -d "username=admin&password=admin&submit=Login" --dump-header headers http://localhost/Login
curl -L -b headers http://localhost/

Pretty-printing the curl results:


If you use npm and nodejs, you can install json package by running this command:

npm install -g json


curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://hostname/resource | json

If you use pip and python, you can install pjson package by running this command:

pip install pjson


curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://hostname/resource | pjson

If you use Python 2.6+, json tool is bundled within.


curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://hostname/resource | python -m json.tool

If you use gem and ruby, you can install colorful_json package by running this command:

gem install colorful_json


curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://hostname/resource | cjson

If you use apt-get (aptitude package manager of your Linux distro), you can install yajl-tools package by running this command:

sudo apt-get install yajl-tools


curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://hostname/resource |  json_reformat

For XML:

If you use *nix with Debian/Gnome envrionment, install libxml2-utils:

sudo apt-get install libxml2-utils


curl -H "Accept: application/xml" -H "Content-Type: application/xml" -X GET http://hostname/resource | xmllint --format -

or install tidy:

sudo apt-get install tidy


curl -H "Accept: application/xml" -H "Content-Type: application/xml" -X GET http://hostname/resource | tidy -xml -i -

Saving the curl response to a file

curl http://hostname/resource >> /path/to/your/file


curl http://hostname/resource -o /path/to/your/file

For detailed description of the curl command, hit:

man curl

For details about options/switches of the curl command, hit:

curl -h

Java: How to read a text file

Using Java 7 to read files with NIO.2

Import these packages:

import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

This is the process to read a file:

Path file = Paths.get("C:\\Java\\file.txt");

if(Files.exists(file) && Files.isReadable(file)) {

    try {
        // File reader
        BufferedReader reader = Files.newBufferedReader(file, Charset.defaultCharset());

        String line;
        // read each line
        while((line = reader.readLine()) != null) {
            // tokenize each number
            StringTokenizer tokenizer = new StringTokenizer(line, " ");
            while (tokenizer.hasMoreElements()) {
                // parse each integer in file
                int element = Integer.parseInt(tokenizer.nextToken());
    } catch (Exception e) {

To read all lines of a file at once:

Path file = Paths.get("C:\\Java\\file.txt");
List<String> lines = Files.readAllLines(file, StandardCharsets.UTF_8);

copy from one database to another using oracle sql developer - connection failed

The copy command is a SQL*Plus command (not a SQL Developer command). If you have your tnsname entries setup for SID1 and SID2 (e.g. try a tnsping), you should be able to execute your command.

Another assumption is that table1 has the same columns as the message_table (and the columns have only the following data types: CHAR, DATE, LONG, NUMBER or VARCHAR2). Also, with an insert command, you would need to be concerned about primary keys (e.g. that you are not inserting duplicate records).

I tried a variation of your command as follows in SQL*Plus (with no errors):

copy from scott/tiger@db1 to scott/tiger@db2 create new_emp using select * from emp;

After I executed the above statement, I also truncate the new_emp table and executed this command:

copy from scott/tiger@db1 to scott/tiger@db2 insert new_emp using select * from emp;

With SQL Developer, you could do the following to perform a similar approach to copying objects:

  1. On the tool bar, select Tools>Database copy.

  2. Identify source and destination connections with the copy options you would like. enter image description here

  3. For object type, select table(s). enter image description here

  4. Specify the specific table(s) (e.g. table1). enter image description here

The copy command approach is old and its features are not being updated with the release of new data types. There are a number of more current approaches to this like Oracle's data pump (even for tables).

How to implement a material design circular progress bar in android

With the Material Components library you can use the CircularProgressIndicator:

Something like:


where array/progress_colors is an array with the colors:

  <integer-array name="progress_colors">

enter image description here

Note: it requires at least the version 1.3.0

Communication between multiple docker-compose projects

You just need to make sure that the containers you want to talk to each other are on the same network. Networks are a first-class docker construct, and not specific to compose.

# front/docker-compose.yml
version: '2'
      - some-net
    driver: bridge


# api/docker-compose.yml
version: '2'
      - front_some-net
    external: true

Note: Your app’s network is given a name based on the “project name”, which is based on the name of the directory it lives in, in this case a prefix front_ was added

They can then talk to each other using the service name. From front you can do ping api and vice versa.

Open Form2 from Form1, close Form1 from Form2

This works:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

How to get the width of a react element

This is basically Marco Antônio's answer for a React custom hook, but modified to set the dimensions initially and not only after a resize.

export const useContainerDimensions = myRef => {
  const getDimensions = () => ({
    width: myRef.current.offsetWidth,
    height: myRef.current.offsetHeight

  const [dimensions, setDimensions] = useState({ width: 0, height: 0 })

  useEffect(() => {
    const handleResize = () => {

    if (myRef.current) {

    window.addEventListener("resize", handleResize)

    return () => {
      window.removeEventListener("resize", handleResize)
  }, [myRef])

  return dimensions;

Used in the same way:

const MyComponent = () => {
  const componentRef = useRef()
  const { width, height } = useContainerDimensions(componentRef)

  return (
    <div ref={componentRef}>
      <p>width: {width}px</p>
      <p>height: {height}px</p>

How do I iterate through each element in an n-dimensional matrix in MATLAB?

You can use linear indexing to access each element.

for idx = 1:numel(array)
    element = array(idx)

This is useful if you don't need to know what i,j,k, you are at. However, if you don't need to know what index you are at, you are probably better off using arrayfun()

Printing newlines with print() in R

Using writeLines also allows you to dispense with the "\n" newline character, by using c(). As in:

writeLines(c("File not supplied.","Usage: ./program F=filename",[additional text for third line]))

This is helpful if you plan on writing a multiline message with combined fixed and variable input, such as the [additional text for third line] above.

Python Accessing Nested JSON Data

I'm using this lib to access nested dict keys

 import requests
 from addict import Dict
 r = requests.get('')
 j = Dict(r.json())

 print j.state
 print j.places[1]['post code']  # only work with keys without '-', space, or starting with number 

How to check if another instance of the application is running

Here are some good sample applications. Below is one possible way.

public static Process RunningInstance() 
    Process current = Process.GetCurrentProcess(); 
    Process[] processes = Process.GetProcessesByName (current.ProcessName); 

    //Loop through the running processes in with the same name 
    foreach (Process process in processes) 
        //Ignore the current process 
        if (process.Id != current.Id) 
            //Make sure that the process is running from the exe file. 
            if (Assembly.GetExecutingAssembly().Location.
                 Replace("/", "\\") == current.MainModule.FileName) 

                //Return the other process instance.  
                return process; 

    //No other instance was found, return null.  
    return null;  

if (MainForm.RunningInstance() != null)
    MessageBox.Show("Duplicate Instance");
    //Your application logic for duplicate 
    //instances would go here.

Many other possible ways. See the examples for alternatives.

First one.

Second One.

Third One

EDIT 1: Just saw your comment that you have got a console application. That is discussed in the second sample.

async await return Task

This is a Task that is returning a Task of type String (C# anonymous function or in other word a delegation is used 'Func')

    public static async Task<string> MyTask()
        //C# anonymous AsyncTask
        return await Task.FromResult<string>(((Func<string>)(() =>
            // your code here
            return  "string result here";


Wipe data/Factory reset through ADB

After a lot of digging around I finally ended up downloading the source code of the recovery section of Android. Turns out you can actually send commands to the recovery.

 * The arguments which may be supplied in the recovery.command file:
 *   --send_intent=anystring - write the text out to recovery.intent
 *   --update_package=path - verify install an OTA package file
 *   --wipe_data - erase user data (and cache), then reboot
 *   --wipe_cache - wipe cache (but not user data), then reboot
 *   --set_encrypted_filesystem=on|off - enables / diasables encrypted fs

Those are the commands you can use according to the one I found but that might be different for modded files. So using adb you can do this:

adb shell
recovery --wipe_data

Using --wipe_data seemed to do what I was looking for which was handy although I have not fully tested this as of yet.


For anyone still using this topic, these commands may change based on which recovery you are using. If you are using Clockword recovery, these commands should still work. You can find other commands in /cache/recovery/command

For more information please see here:

Using Mockito to test abstract classes

What really makes me feel bad about mocking abstract classes is the fact, that neither the default constructor YourAbstractClass() gets called (missing super() in mock) nor seems there to be any way in Mockito to default initialize mock properties (e.g List properties with empty ArrayList or LinkedList).

My abstract class (basically the class source code gets generated) does NOT provide a dependency setter injection for list elements, nor a constructor where it initializes the list elements (which I tried to add manually).

Only the class attributes use default initialization:

private List<MyGenType> dep1 = new ArrayList<MyGenType>();
private List<MyGenType> dep2 = new ArrayList<MyGenType>();

So there is NO way to mock an abstract class without using a real object implementation (e.g inner class definition in unit test class, overriding abstract methods) and spying the real object (which does proper field initialization).

Too bad that only PowerMock would help here further.

C++ Fatal Error LNK1120: 1 unresolved externals

My problem was int Main() instead of int main()

good luck

Play audio as microphone input

Just as there are printer drivers that do not connect to a printer at all but rather write to a PDF file, analogously there are virtual audio drivers available that do not connect to a physical microphone at all but can pipe input from other sources such as files or other programs.

I hope I'm not breaking any rules by recommending free/donation software, but VB-Audio Virtual Cable should let you create a pair of virtual input and output audio devices. Then you could play an MP3 into the virtual output device and then set the virtual input device as your "microphone". In theory I think that should work.

If all else fails, you could always roll your own virtual audio driver. Microsoft provides some sample code but unfortunately it is not applicable to the older Windows XP audio model. There is probably sample code available for XP too.

Horizontal scroll css?

I figured it this way:

* { padding: 0; margin: 0 }
body { height: 100%; white-space: nowrap }
html { height: 100% }

.red { background: red }
.blue { background: blue }
.yellow { background: yellow }

.header { width: 100%; height: 10%; position: fixed }
.wrapper { width: 1000%; height: 100%; background: green }
.page { width: 10%; height: 100%; float: left }

<div class="header red"></div>
<div class="wrapper">
    <div class="page yellow"></div>
    <div class="page blue"></div>
    <div class="page yellow"></div>
    <div class="page blue"></div>
    <div class="page yellow"></div>
    <div class="page blue"></div>
    <div class="page yellow"></div>
    <div class="page blue"></div>
    <div class="page yellow"></div>
    <div class="page blue"></div>

I have the wrapper at 1000% and ten pages at 10% each. I set mine up to still have "pages" with each being 100% of the window (color coded). You can do eight pages with an 800% wrapper. I guess you can leave out the colors and have on continues page. I also set up a fixed header, but that's not necessary. Hope this helps.

Bootstrap modal not displaying

In order to get my modal to display when calling .modal('show')

I changed:

modal.on('', function() 


modal.on('', function() {

Which one is the best PDF-API for PHP?

I found mpdf better than tcpdf in terms of html rendering. It can parse css styles much better and create pdf that look very similar to the original html.

mpdf even supports css things like border-radius and gradient etc.

I am surprised to see why mpdf is so less talked about when it comes to html to pdf.

Check out the examples here

I found it useful for designing invoices, receipts and simple prints etc. However the website itself says that pdfs generated from mpdf tend to be larger in size.

Excel VBA - read cell value from code

I think you need this ..

Dim n as Integer   

For n = 5 to 17
  msgbox cells(n,3) '--> sched waste
  msgbox cells(n,4) '--> type of treatm
  msgbox format(cells(n,5),"dd/MM/yyyy") '--> Lic exp
  msgbox cells(n,6) '--> email col

Android Shared preferences for creating one time activity (example)

public class Preferences {

public static final String PREF_NAME = "your preferences name";

public static final int MODE = Context.MODE_WORLD_WRITEABLE;

public static final String USER_ID = "USER_ID_NEW";
public static final String USER_NAME = "USER_NAME";

public static final String NAME = "NAME";
public static final String EMAIL = "EMAIL";
public static final String PHONE = "PHONE";
public static final String address = "address";

public static void writeBoolean(Context context, String key, boolean value) {
    getEditor(context).putBoolean(key, value).commit();

public static boolean readBoolean(Context context, String key,
        boolean defValue) {
    return getPreferences(context).getBoolean(key, defValue);

public static void writeInteger(Context context, String key, int value) {
    getEditor(context).putInt(key, value).commit();


public static int readInteger(Context context, String key, int defValue) {
    return getPreferences(context).getInt(key, defValue);

public static void writeString(Context context, String key, String value) {
    getEditor(context).putString(key, value).commit();


public static String readString(Context context, String key, String defValue) {
    return getPreferences(context).getString(key, defValue);

public static void writeFloat(Context context, String key, float value) {
    getEditor(context).putFloat(key, value).commit();

public static float readFloat(Context context, String key, float defValue) {
    return getPreferences(context).getFloat(key, defValue);

public static void writeLong(Context context, String key, long value) {
    getEditor(context).putLong(key, value).commit();

public static long readLong(Context context, String key, long defValue) {
    return getPreferences(context).getLong(key, defValue);

public static SharedPreferences getPreferences(Context context) {
    return context.getSharedPreferences(PREF_NAME, MODE);

public static Editor getEditor(Context context) {
    return getPreferences(context).edit();


****Use Preferences to Write value using:-****

                    Preferences.NAME, "dev");

****Use Preferences to Read value using:-****

Preferences.readString(getApplicationContext(), Preferences.NAME,

How can I redirect a php page to another php page?

Send a Location header to redirect. Keep in mind this only works before any other output is sent.

header('Location: index.php'); // redirect to index.php

convert string to specific datetime format?

More formats:

 require 'date'

 date = "01/07/2016 09:17AM"
 DateTime.parse(date).strftime("%A, %b %d")
 #=> Friday, Jul 01

 #=> 07/01/2016

 DateTime.parse(date).strftime("%m-%e-%y %H:%M")
 #=> 07- 1-16 09:17

 DateTime.parse(date).strftime("%b %e")
 #=> Jul  1

 DateTime.parse(date).strftime("%l:%M %p")
 #=>  9:17 AM

 DateTime.parse(date).strftime("%B %Y")
 #=> July 2016
 DateTime.parse(date).strftime("%b %d, %Y")
 #=> Jul 01, 2016
 DateTime.parse(date).strftime("%a, %e %b %Y %H:%M:%S %z")
 #=> Fri,  1 Jul 2016 09:17:00 +0200
 #=> 2016-07-01T 9:17:00+0200
 DateTime.parse(date).strftime("%I:%M:%S %p")
 #=> 09:17:00 AM
 #=> 09:17:00
 DateTime.parse(date).strftime("%e %b %Y %H:%M:%S%p")
 #=>  1 Jul 2016 09:17:00AM
 #=> 01.07.16
 DateTime.parse(date).strftime("%A, %d %b %Y %l:%M %p")
 #=> Friday, 01 Jul 2016  9:17 AM

Laravel redirect back to original destination after login

For laravel 5.* try these.

return redirect()->intended('/');


return Redirect::intended('/');

Maven error in eclipse (pom.xml) : Failure to transfer org.apache.maven.plugins:maven-surefire-plugin:pom:2.12.4

You need just to follow those steps:

  1. Right Click on your project: Run (As) -> Maven clean
  2. Right Click on your project: Run (As) -> Maven install

After which, if the build fails when you do Maven Install, it means there is no web.xml file under WEB-INF or some problem associated with it. it really works

Python Replace \\ with \

r'a\\nb'.replace('\\\\', '\\')


'a\nb'.replace('\n', '\\n')

Getting error "The package appears to be corrupt" while installing apk file

After searching a lot I found a solution:

Go to Build-> Build Apk(s).

After creating apk you will see a dialog as below.

enter image description here

Click on locate and install it in your phone


Writing a string to a cell in excel

I've had a few cranberry-vodkas tonight so I might be missing something...Is setting the range necessary? Why not use:

Activeworkbook.Sheets("Game").Range("A1").value = "Subtotal"

Does this fail as well?

Looks like you tried something similar:

'Worksheets("Game").Range("A1") = "Asdf"

However, Worksheets is a collection, so you can't reference "Game". I think you need to use the Sheets object instead.

Bootstrap datetimepicker is not a function

Below is the right code. Include JS files in following manner:

$(document).ready(function() {_x000D_
  $(function() {_x000D_
      useCurrent: false //Important! See issue #1075_x000D_
    $("#datetimepicker6").on("dp.change", function(e) {_x000D_
    $("#datetimepicker7").on("dp.change", function(e) {_x000D_
<!-- Latest compiled and minified CSS -->_x000D_
<link rel="stylesheet" href="">_x000D_
<!-- Optional theme -->_x000D_
<link rel="stylesheet" href="">_x000D_
<link rel="stylesheet" href="" />_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
  <div class="container">_x000D_
    <div class='col-md-5'>_x000D_
      <div class="form-group">_x000D_
        <div class='input-group date' id='datetimepicker6'>_x000D_
          <input type='text' class="form-control" />_x000D_
          <span class="input-group-addon">_x000D_
                        <span class="glyphicon glyphicon-calendar"></span>_x000D_
    <div class='col-md-5'>_x000D_
      <div class="form-group">_x000D_
        <div class='input-group date' id='datetimepicker7'>_x000D_
          <input type='text' class="form-control" />_x000D_
          <span class="input-group-addon">_x000D_
                        <span class="glyphicon glyphicon-calendar"></span>_x000D_

Take n rows from a spark dataframe and pass to toPandas()

You can use the limit(n) function:

l = [('Alice', 1),('Jim',2),('Sandra',3)]
df = sqlContext.createDataFrame(l, ['name', 'age'])
df.limit(2).withColumn('age2', df.age + 2).toPandas()


l = [('Alice', 1),('Jim',2),('Sandra',3)]
df = sqlContext.createDataFrame(l, ['name', 'age'])
df.withColumn('age2', df.age + 2).limit(2).toPandas()

set the width of select2 input (through Angular-ui directive)

Add width resolve option to your select2 function

$(document).ready(function() { 
        $("#myselect").select2({ width: 'resolve' });           

After add below CSS to your stylesheet

.select2-container {
width: 100% !important;

It will sort the issue

CSS3 transition events

W3C CSS Transitions Draft

The completion of a CSS Transition generates a corresponding DOM Event. An event is fired for each property that undergoes a transition. This allows a content developer to perform actions that synchronize with the completion of a transition.


To determine when a transition completes, set a JavaScript event listener function for the DOM event that is sent at the end of a transition. The event is an instance of WebKitTransitionEvent, and its type is webkitTransitionEnd.

box.addEventListener( 'webkitTransitionEnd', 
    function( event ) { alert( "Finished transition!" ); }, false );


There is a single event that is fired when transitions complete. In Firefox, the event is transitionend, in Opera, oTransitionEnd, and in WebKit it is webkitTransitionEnd.


There is one type of transition event available. The oTransitionEnd event occurs at the completion of the transition.

Internet Explorer

The transitionend event occurs at the completion of the transition. If the transition is removed before completion, the event will not fire.

Stack Overflow: How do I normalize CSS3 Transition functions across browsers?

how to measure running time of algorithms in python

I am not 100% sure what is meant by "running times of my algorithms written in python", so I thought I might try to offer a broader look at some of the potential answers.

  • Algorithms don't have running times; implementations can be timed, but an algorithm is an abstract approach to doing something. The most common and often the most valuable part of optimizing a program is analyzing the algorithm, usually using asymptotic analysis and computing the big O complexity in time, space, disk use and so forth.

    A computer cannot really do this step for you. This requires doing the math to figure out how something works. Optimizing this side of things is the main component to having scalable performance.

  • You can time your specific implementation. The nicest way to do this in Python is to use timeit. The way it seems most to want to be used is to make a module with a function encapsulating what you want to call and call it from the command line with python -m timeit ....

    Using timeit to compare multiple snippets when doing microoptimization, but often isn't the correct tool you want for comparing two different algorithms. It is common that what you want is asymptotic analysis, but it's possible you want more complicated types of analysis.

  • You have to know what to time. Most snippets aren't worth improving. You need to make changes where they actually count, especially when you're doing micro-optimisation and not improving the asymptotic complexity of your algorithm.

    If you quadruple the speed of a function in which your code spends 1% of the time, that's not a real speedup. If you make a 20% speed increase on a function in which your program spends 50% of the time, you have a real gain.

    To determine the time spent by a real Python program, use the stdlib profiling utilities. This will tell you where in an example program your code is spending its time.

How can I make my layout scroll both horizontally and vertically?

In this post Scrollview vertical and horizontal in android they talk about a possible solution, quoting:

Matt Clark has built a custom view based on the Android source, and it seems to work perfectly:

Beware that the class in that page has a bug calculating the view's horizonal width. A fix by Manuel Hilty is in the comments:

Solution: Replace the statement on line 808 by the following:

final int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(lp.leftMargin + lp.rightMargin, MeasureSpec.UNSPECIFIED);

Convert MySql DateTime stamp into JavaScript's Date format

From Andy's Answer, For AngularJS - Filter

    .module('utils', [])
.filter('mysqlToJS', function () {
            return function (mysqlStr) {
                var t, result = null;

                if (typeof mysqlStr === 'string') {
                    t = mysqlStr.split(/[- :]/);

                    //when t[3], t[4] and t[5] are missing they defaults to zero
                    result = new Date(t[0], t[1] - 1, t[2], t[3] || 0, t[4] || 0, t[5] || 0);

                return result;

What is the difference between _tmain() and main() in C++?

the _T convention is used to indicate the program should use the character set defined for the application (Unicode, ASCII, MBCS, etc.). You can surround your strings with _T( ) to have them stored in the correct format.

 cout << _T( "There are " ) << argc << _T( " arguments:" ) << endl;

Nested Git repositories?


Can I nest git repositories?

Yes. However, by default git does not track the .git folder of the nested repository. Git has features designed to manage nested repositories (read on).

Does it make sense to git init/add the /project_root to ease management of everything locally or do I have to manage my_project and the 3rd party one separately?

It probably doesn't make sense as git has features to manage nested repositories. Git's built in features to manage nested repositories are submodule and subtree.

Here is a blog on the topic and here is a SO question that covers the pros and cons of using each.

How to make flutter app responsive according to different screen size?

You can use MediaQuery for parent's dimension or FractionallySizedBox as containers.

Visual Studio 6 Windows Common Controls 6.0 (sp6) Windows 7, 64 bit

I had the problem whereby VB6 IDE would not load the common controls (Sp6)with VB6 install on W7 64bit, specifically comctrl and msmask. I tried all the solutions proposed using regsrv32 (elevated), edited the registry, changing the version number in the vbp etc as proposed by MS and others. All failed. These solutions worked on my other 2 PCS but not this one. Eventually I removed IE11 and all worked properly afterwards. IE10 had never bene installed on thsi PC - we went straight from IE8 to IE11 and have been forced to backtrack to using IE8.

I have to say the simple solution above does not address the problem which is that the VB6 IDE will not load the common controls (using the Components menu selection under Project) - you get an error saying Object not loaded. So this will happen (and I proved this to myself) on any project, new or old that try to use theose common controls that will not load.

So my suggestion to anyone who has this problem is to try the manual register solution using regsrv32 route, then the edit the vbp to change the version, and if these fail uninstall IE11 (and defintely IE10). But this may still not be a 100% solution because if your existing project files ".vbp" contain references to the wrong common controls you need to correct that manually - this is where loading a new project, loading the Components you need inside the IDE, then edit the newly create vbp using notepad and copy the version numbers for the common controls to your existing vbp files.

Simple InputBox function

The simplest way to get an input box is with the Read-Host cmdlet and -AsSecureString parameter.

$us = Read-Host 'Enter Your User Name:' -AsSecureString
$pw = Read-Host 'Enter Your Password:' -AsSecureString

This is especially useful if you are gathering login info like my example above. If you prefer to keep the variables obfuscated as SecureString objects you can convert the variables on the fly like this:


If the info does not need to be secure at all you can convert it to plain text:

$user = [Runtime.InteropServices.Marshal]::PtrToStringAuto([Runtime.InteropServices.Marshal]::SecureStringToBSTR($us))

Read-Host and -AsSecureString appear to have been included in all PowerShell versions (1-6) but I do not have PowerShell 1 or 2 to ensure the commands work identically.

Check for internet connection with Swift

Although it does not directly answers your question, I would like to mention Apple recentely had this talk:

At around 09:55 he talks about doing this stuff you are asking about:

  1. Check connection
  2. If connection -> Do something
  3. If no connection -> Do something else (wait? retry?)

However, this has a few pitfalls:

  • What if in step 2 it says it has a connection, but 0.5 seconds later he hasn't?
  • What if the user is behind a proxy
  • Last but not least, what if some answers here can not determine the connectivity right? (I am sure that if you rapidly switch your connection, go to wi-fi and turn it off (just make it complicated), it almost never can correctly determine whetever I got a connection or not).
  • Quote from the video: "There is no way to guarentee whether a future operation will succeed or not"

The following points are some best practices according to Apple:

According to the talk, there shouldn't be any reason to pre-check whetever you got internet connection or not, since it may not be accurate at the time you send your request to the server.

Is there a Max function in SQL Server that takes two values like Math.Max in .NET?

If you're using SQL Server 2008 (or above), then this is the better solution:

SELECT o.OrderId,
       (SELECT MAX(Price)
        FROM (VALUES (o.NegotiatedPrice),(o.SuggestedPrice)) AS AllPrices(Price))
FROM Order o

All credit and votes should go to Sven's answer to a related question, "SQL MAX of multiple columns?"
I say it's the "best answer" because:

  1. It doesn't require complicating your code with UNION's, PIVOT's, UNPIVOT's, UDF's, and crazy-long CASE statments.
  2. It isn't plagued with the problem of handling nulls, it handles them just fine.
  3. It's easy to swap out the "MAX" with "MIN", "AVG", or "SUM". You can use any aggregate function to find the aggregate over many different columns.
  4. You're not limited to the names I used (i.e. "AllPrices" and "Price"). You can pick your own names to make it easier to read and understand for the next guy.
  5. You can find multiple aggregates using SQL Server 2008's derived_tables like so:
    SELECT MAX(a), MAX(b) FROM (VALUES (1, 2), (3, 4), (5, 6), (7, 8), (9, 10) ) AS MyTable(a, b)

How can I disable a specific LI element inside a UL?

Using CSS3:

If that's not an option for any reason, you could try giving the list items classes:

<li class="one"></li>
<li class="two"></li>
<li class="three"></li>

Then in your css:{display:none}/*hide first li*/
li.three{display:none}/*hide third li*/

Apache won't start in wamp

I was having same problem.

I followed this steps, problem solved.

run command line (CMD) with Administrator Permission.

cd c:/wamp64/bin/apache/apache2.4.27/bin

httpd.exe -k uninstall

httpd.exe -k install

at last restart all services from wamp system tray icon

The VMware Authorization Service is not running

This problem was solved for me by running VMware workstation as Windows administrator. From the start menu right click on the VMware workstation, then select "Run as Administrator"

How to downgrade or install an older version of Cocoapods

Note that your pod specs will remain, and are located at ~/.cocoapods/ . This directory may also need to be removed if you want a completely fresh install.

They can be removed using pod spec remove SPEC_NAME then pod setup

It may help to do pod spec remove master then pod setup

How to resize array in C++?

  1. Use std::vector or
  2. Write your own method. Allocate chunk of memory using new. with that memory you can expand till the limit of memory chunk.

How to write to a file, using the logging Python module?

Here is two examples, one print the logs (stdout) the other write the logs to a file:

import logging
import sys

logger = logging.getLogger()
formatter = logging.Formatter('%(asctime)s | %(levelname)s | %(message)s')

stdout_handler = logging.StreamHandler(sys.stdout)

file_handler = logging.FileHandler('logs.log')


With this example, all logs will be printed and also be written to a file named logs.log

Use example:'This is a log message!')
logger.error('This is an error message.')

Set value for particular cell in pandas DataFrame using index

If one wants to change the cell in the position (0,0) of the df to a string such as '"236"76"', the following options will do the work:

df[0][0] = '"236"76"'
# %timeit df[0][0] = '"236"76"'
# 938 µs ± 83.4 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

Or using[0, 0] = '"236"76"'
#  %timeit[0, 0] = '"236"76"' 
#15 µs ± 2.09 µs per loop (mean ± std. dev. of 7 runs, 100000 loops each)

Or using pandas.DataFrame.iat

df.iat[0, 0] = '"236"76"'
#  %timeit df.iat[0, 0] = '"236"76"'
# 41.1 µs ± 3.09 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)

Or using pandas.DataFrame.loc

df.loc[0, 0] = '"236"76"'
#  %timeit df.loc[0, 0] = '"236"76"'
# 5.21 ms ± 401 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)

Or using pandas.DataFrame.iloc

df.iloc[0, 0] = '"236"76"'
#  %timeit df.iloc[0, 0] = '"236"76"'
# 5.12 ms ± 300 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)

If time is of relevance, using is the fastest approach.

Set Value of Input Using Javascript Function

I'm not using YUI, but in case it helps anyone else - my issue was that I had duplicate ID's on the page (was working inside a dialog and forgot about the page underneath).

Changing the ID so it was unique allowed me to use the methods listed in Sangeet's answer.

Using global variables in a function

Writing to explicit elements of a global array does not apparently need the global declaration, though writing to it "wholesale" does have that requirement:

import numpy as np

hostValue = 3.14159
hostArray = np.array([2., 3.])
hostMatrix = np.array([[1.0, 0.0],[ 0.0, 1.0]])

def func1():
    global hostValue    # mandatory, else local.
    hostValue = 2.0

def func2():
    global hostValue    # mandatory, else UnboundLocalError.
    hostValue += 1.0

def func3():
    global hostArray    # mandatory, else local.
    hostArray = np.array([14., 15.])

def func4():            # no need for globals
    hostArray[0] = 123.4

def func5():            # no need for globals
    hostArray[1] += 1.0

def func6():            # no need for globals
    hostMatrix[1][1] = 12.

def func7():            # no need for globals
    hostMatrix[0][0] += 0.33

print "After func1(), hostValue = ", hostValue
print "After func2(), hostValue = ", hostValue
print "After func3(), hostArray = ", hostArray
print "After func4(), hostArray = ", hostArray
print "After func5(), hostArray = ", hostArray
print "After func6(), hostMatrix = \n", hostMatrix
print "After func7(), hostMatrix = \n", hostMatrix

importing pyspark in python shell

You can get the pyspark path in python using pip (if you have installed pyspark using PIP) as below

pip show pyspark

Get filename from input [type='file'] using jQuery

There is no jQuery function for this. You have to access the DOM element and check the files property.




addEventListener vs onclick

in my Visual Studio Code, addEventListener has Real Intellisense on event

enter image description here

but onclick does not, only fake ones

enter image description here

How to know the git username and email saved during configuration?

List all variables set in the config file, along with their values.

git config --list

If you are new to git then use the following commands to set a user name and email address.

Set user name

git config --global "your Name"

Set user email

git config --global "[email protected]"

Check user name

git config

Check user email

git config

Best way to do nested case statement logic in SQL Server

I personally do it this way, keeping the embedded CASE expressions confined. I'd also put comments in to explain what is going on. If it is too complex, break it out into function.

    CASE WHEN condition THEN
      CASE WHEN condition1 THEN
        CASE WHEN condition2 THEN calculation1
        ELSE calculation2 END
        CASE WHEN condition2 THEN calculation3
        ELSE calculation4 END
    ELSE CASE WHEN condition1 THEN 
      CASE WHEN condition2 THEN calculation5
      ELSE calculation6 END
    ELSE CASE WHEN condition2 THEN calculation7
         ELSE calculation8 END
    END AS 'calculatedcol1',
    col5 -- etc
FROM table

How can I tail a log file in Python?

Non Blocking

If you are on linux (as windows does not support calling select on files) you can use the subprocess module along with the select module.

import time
import subprocess
import select

f = subprocess.Popen(['tail','-F',filename],\
p = select.poll()

while True:
    if p.poll(1):
        print f.stdout.readline()

This polls the output pipe for new data and prints it when it is available. Normally the time.sleep(1) and print f.stdout.readline() would be replaced with useful code.


You can use the subprocess module without the extra select module calls.

import subprocess
f = subprocess.Popen(['tail','-F',filename],\
while True:
    line = f.stdout.readline()
    print line

This will also print new lines as they are added, but it will block until the tail program is closed, probably with f.kill().

How organize uploaded media in WP?

You can use the Media Library Folders plugin. It allows you to create folders, move or copy images to a folder and even includes a sync function to bulk add images uploaded by FTP to the server to the Wordpress media library.

Media Library Folders example