Programs & Examples On #Let

In Lisp-like and functional languages, introduces a list of local variables, each (possibly optionally) with its initial value.

Why was the name 'let' chosen for block-scoped variable declarations in JavaScript?

Adding to exebook's response, the mathematics usage of the keyword let also encapsulates well the scoping implications of let when used in Javascript/ES6. Specifically, just as the following ES6 code is not aware of the assignment in braces of toPrint when it prints out the value of 'Hello World',

let toPrint = 'Hello World.';
    let toPrint = 'Goodbye World.';
console.log(toPrint); // Prints 'Hello World'

let as used in formalized mathematics (especially the writing of proofs) indicates that the current instance of a variable exists only for the scope of that logical idea. In the following example, x immediately gains a new identity upon entering the new idea (usually these are concepts necessary to prove the main idea) and reverts immediately to the old x upon the conclusion of the sub-proof. Of course, just as in coding, this is considered somewhat confusing and so is usually avoided by choosing a different name for the other variable.

Let x be so and so...

  Proof stuff

 New Idea { Let x be something else ... prove something } Conclude New Idea

 Prove main idea with old x

What's the difference between using "let" and "var"?

The difference is in the scope of the variables declared with each.

In practice, there are a number of useful consequences of the difference in scope:

  1. let variables are only visible in their nearest enclosing block ({ ... }).
  2. let variables are only usable in lines of code that occur after the variable is declared (even though they are hoisted!).
  3. let variables may not be redeclared by a subsequent var or let.
  4. Global let variables are not added to the global window object.
  5. let variables are easy to use with closures (they do not cause race conditions).

The restrictions imposed by let reduce the visibility of the variables and increase the likelihood that unexpected name collisions will be found early. This makes it easier to track and reason about variables, including their reachability(helping with reclaiming unused memory).

Consequently, let variables are less likely to cause problems when used in large programs or when independently-developed frameworks are combined in new and unexpected ways.

var may still be useful if you are sure you want the single-binding effect when using a closure in a loop (#5) or for declaring externally-visible global variables in your code (#4). Use of var for exports may be supplanted if export migrates out of transpiler space and into the core language.


1. No use outside nearest enclosing block: This block of code will throw a reference error because the second use of x occurs outside of the block where it is declared with let:

    let x = 1;
console.log(`x is ${x}`);  // ReferenceError during parsing: "x is not defined".

In contrast, the same example with var works.

2. No use before declaration:
This block of code will throw a ReferenceError before the code can be run because x is used before it is declared:

    x = x + 1;  // ReferenceError during parsing: "x is not defined".
    let x;
    console.log(`x is ${x}`);  // Never runs.

In contrast, the same example with var parses and runs without throwing any exceptions.

3. No redeclaration: The following code demonstrates that a variable declared with let may not be redeclared later:

let x = 1;
let x = 2;  // SyntaxError: Identifier 'x' has already been declared

4. Globals not attached to window:

var button = "I cause accidents because my name is too common.";
let link = "Though my name is common, I am harder to access from other JS files.";
console.log(link);  // OK
console.log(;  // undefined (GOOD!)
console.log(window.button);  // OK

5. Easy use with closures: Variables declared with var do not work well with closures inside loops. Here is a simple loop that outputs the sequence of values that the variable i has at different points in time:

for (let i = 0; i < 5; i++) {
    console.log(`i is ${i}`), 125/*ms*/);

Specifically, this outputs:

i is 0
i is 1
i is 2
i is 3
i is 4

In JavaScript we often use variables at a significantly later time than when they are created. When we demonstrate this by delaying the output with a closure passed to setTimeout:

for (let i = 0; i < 5; i++) {
    setTimeout(_ => console.log(`i is ${i}`), 125/*ms*/);

... the output remains unchanged as long as we stick with let. In contrast, if we had used var i instead:

for (var i = 0; i < 5; i++) {
    setTimeout(_ => console.log(`i is ${i}`), 125/*ms*/);

... the loop unexpectedly outputs "i is 5" five times:

i is 5
i is 5
i is 5
i is 5
i is 5

How to convert java.sql.timestamp to LocalDate (java8) java.time?

I'll slightly expand @assylias answer to take time zone into account. There are at least two ways to get LocalDateTime for specific time zone.

You can use setDefault time zone for whole application. It should be called before any timestamp -> java.time conversion:

public static void main(String... args) {
    TimeZone utcTimeZone = TimeZone.getTimeZone("UTC");

Or you can use toInstant.atZone chain:


Using find command in bash script

You can use this:

list=$(find /home/user/Desktop -name '*.pdf' -o -name '*.txt' -o -name '*.bmp')

Besides, you might want to use -iname instead of -name to catch files with ".PDF" (upper-case) extension as well.

What order are the Junit @Before/@After called?

You can use @BeforeClass annotation to assure that setup() is always called first. Similarly, you can use @AfterClass annotation to assure that tearDown() is always called last.

This is usually not recommended, but it is supported.

It's not exactly what you want - but it'll essentially keep your DB connection open the entire time your tests are running, and then close it once and for all at the end.

TimeStamp on file name using PowerShell


$filenameFormat = "" + " " + (Get-Date -Format "yyyy-MM-dd")
Rename-Item -Path "C:\temp\" -NewName $filenameFormat

socket.emit() vs. socket.send()

socket.send // Sends a message event

socket.emit(eventName[, ...args][, ack]) // you can custom eventName

Enable VT-x in your BIOS security settings (refer to documentation for your computer)

I had similar issues and below is how i fixed it:

  • Restart your PC, when booting up press f10 key to select or open BIOS Settings.
  • Locate and check / enable Virtual Technology-x option under Device Configuration Settings
  • Save changes, system restart.
  • All should be working fine now

Initialising mock objects - MockIto

MockitoAnnotations & the runner have been well discussed above, so I'm going to throw in my tuppence for the unloved:

XXX mockedXxx = mock(XXX.class);

I use this because I find it a little bit more descriptive and I prefer (not out right ban) unit tests not to use member variables as I like my tests to be (as much as they can be) self contained.

How to get rows count of internal table in abap?

Beside the recommended

DESCRIBE TABLE <itab-Name> LINES <variable>

there is also the system variable SY-TFILL.

From documentation:

After the statements DESCRIBE TABLE, LOOP AT and READ TABLE, the number of rows of the accessed internal table.

Example script:

REPORT ytest.


  APPEND '1' TO pf_exclude.
  APPEND '2' TO pf_exclude.
  APPEND '3' TO pf_exclude.
  APPEND '4' TO pf_exclude.

  WRITE: / 'sy-tfill = ', sy-tfill.

  DESCRIBE TABLE pf_exclude.
  WRITE: / 'sy-tfill = ', sy-tfill, 'after describe table'.

  sy-tfill = 0. "Reset
  WRITE: / 'sy-tfill = ', sy-tfill, 'after read table'.

  sy-tfill = 0. "Reset
  LOOP AT pf_exclude.
    WRITE: / 'sy-tfill = ', sy-tfill, 'in loop with', pf_exclude.
    sy-tfill = 0. "Reset

The result:

sy-tfill =           0
sy-tfill =           4  after describe tabl
sy-tfill =           4  after read table
sy-tfill =           4  in loop with 1
sy-tfill =           0  in loop with 2
sy-tfill =           0  in loop with 3
sy-tfill =           0  in loop with 4

Please get attention of the value 0 for the 2nd entry: SY-TFILL is not updated with each step, only after the first loop.

I recommend the usage SY-TFILL only, if you need it direct after the READ(1)... If there are other commands between the READ and the usage of SY-TFILL, there is always the danger of a change of the system variable.

(1) or describe table.

What is the total amount of public IPv4 addresses?

Public IP Addresses will generate a list of Valid IP Public Addresses including Localities.

'' to '' are the valid public IP Address range exclusive of the reserved Private IP Addresses as follows:

import iptools
## Private IP Addresses
private_ips = iptools.IpRangeList(
    '',      '',     '', '',
    '', '',  '',  '',
    '', '', '', '',
    '', '',    '',   ''

IP Generator

Generates a JSON dump of IP Addresses and associated Geo information. Note that the valid public IP Address range is from '' to '' excluding the reserved Private IP Address ranges shown lower down in this readme.

docker build -t geo-ip .
docker run -e IPRANGE='' geo-ip               ## a few IPs
docker run -e IPRANGE='' geo-ip               ## a few more IPs
docker run -e IPRANGE='' geo-ip               ## a lot more IPs
docker run -e IPRANGE=''   geo-ip               ## ALL IPs ( slooooowwwwww )
docker run -e IPRANGE=''   geo-ip > geo-ip.json ## ALL IPs saved to JSON File
docker run geo-ip 

A little faster option for scanning all valid public addresses:

for i in $(seq 1 191); do \
    docker run -e IPRANGE="$i.0.0.0/8" geo-ip; \
    sleep 1; \ 

This prints less than 4,228,250,625 JSON lines to STDOUT. Here is an example of one of the lines:

{"city": "Palo Alto", "ip": "", "longitude": -122.1274,
 "continent": "North America", "continent_code": "NA",
 "state": "California", "country": "United States", "latitude": 37.418,
 "iso_code": "US", "state_code": "CA", "aso": "PubNub",
 "asn": "11404", "zip_code": "94107"}

Private and Reserved IP Range

The dockerfile in the repo above will exclude non-usable IP addresses following the guide from the wikipedia article:

MaxMind Geo IP

The dockerfile imports a free public Database provided by

Java for loop syntax: "for (T obj : objects)"

for each S3ObjecrSummary in objectListing.getObjectSummaries()

it's looping through each item in the collection

How to add a default "Select" option to this ASP.NET DropDownList control?

The reason it is not working is because you are adding an item to the list and then overriding the whole list with a new DataSource which will clear and re-populate your list, losing the first manually added item.

So, you need to do this in reverse like this:

Status status = new Status();
DropDownList1.DataSource = status.getData();
DropDownList1.DataValueField = "ID";
DropDownList1.DataTextField = "Description";

// Then add your first item
DropDownList1.Items.Insert(0, "Select");

how to check and set max_allowed_packet mysql variable

The following PHP worked for me (using mysqli extension but queries should be the same for other extensions):

$db = new mysqli( 'localhost', 'user', 'pass', 'dbname' );
// to get the max_allowed_packet
$maxp = $db->query( 'SELECT @@global.max_allowed_packet' )->fetch_array();
echo $maxp[ 0 ];
// to set the max_allowed_packet to 500MB
$db->query( 'SET @@global.max_allowed_packet = ' . 500 * 1024 * 1024 );

So if you've got a query you expect to be pretty long, you can make sure that mysql will accept it with something like:

$sql = "some really long sql query...";
$db->query( 'SET @@global.max_allowed_packet = ' . strlen( $sql ) + 1024 );
$db->query( $sql );

Notice that I added on an extra 1024 bytes to the length of the string because according to the manual,

The value should be a multiple of 1024; nonmultiples are rounded down to the nearest multiple.

That should hopefully set the max_allowed_packet size large enough to handle your query. I haven't tried this on a shared host, so the same caveat as @Glebushka applies.

Javascript: Fetch DELETE and PUT requests

Just Simple Answer. FETCH DELETE

function deleteData(item, url) {
  return fetch(url + '/' + item, {
    method: 'delete'
  .then(response => response.json());

How to get input from user at runtime

its very simple

just write:

//first create table named test....

create table test (name varchar2(10),age number(5));

//when you run the above code a table will be created....

//now we have to insert a name & an age..

Make sure age will be inserted via opening a form that seeks our help to enter the value in it

insert into test values('Deepak', :age);

//now run the above code and you'll get "1 row inserted" output...

/now run the select query to see the output

select * from test;

//that's all ..Now i think no one has any queries left over accepting a user data...

How to auto-format code in Eclipse?

This can also be done at the Project Level: In the Package Explorer, right-click on the project > Properties > Java Editor > Save Actions

This might be preferable when working as a team so that everyone's code is saved with the same format settings.

How to create a connection string in c#

Add this connection string tag in web.config file:

  <add name="itmall" 
    connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=D:\19-02\ABCC\App_Data\abcc.mdf;Integrated Security=True;User Instance=True"/>

And use it like you mentioned. :)

Scripting Language vs Programming Language

All scripting languages are programming languages.

Languages are not classed as script or not - it entirely depends on the execution environment.

If the environment is one that is interpreted, this is commonly referred to as a scripting environment.

Multiple variables in a 'with' statement?

Note that if you split the variables into lines, you must use backslashes to wrap the newlines.

with A() as a, \
     B() as b, \
     C() as c:

Parentheses don't work, since Python creates a tuple instead.

with (A(),

Since tuples lack a __enter__ attribute, you get an error (undescriptive and does not identify class type):

AttributeError: __enter__

If you try to use as within parentheses, Python catches the mistake at parse time:

with (A() as a,
      B() as b,
      C() as c):
SyntaxError: invalid syntax

When will this be fixed?

This issue is tracked in

Recently, Python announced in PEP 617 that they'll be replacing the current parser with a new one. Because Python's current parser is LL(1), it cannot distinguish between "multiple context managers" with (A(), B()): and "tuple of values" with (A(), B())[0]:.

The new parser can properly parse "multiple context managers" surrounded by tuples. The new parser will be enabled in 3.9, but this syntax will still be rejected until the old parser is removed in Python 3.10.

Read next word in java

You do not necessarily have to split the line because java.util.Scanner's default delimiter is whitespace.

You can just create a new Scanner object within your while statement.

    Scanner sc2 = null;
    try {
        sc2 = new Scanner(new File("translate.txt"));
    } catch (FileNotFoundException e) {
    while (sc2.hasNextLine()) {
            Scanner s2 = new Scanner(sc2.nextLine());
        while (s2.hasNext()) {
            String s =;

error: expected unqualified-id before ‘.’ token //(struct)

The struct's name is ReducedForm; you need to make an object (instance of the struct or class) and use that. Do this:

ReducedForm MyReducedForm;
MyReducedForm.iSimplifiedNumerator = iNumerator/iGreatCommDivisor;
MyReducedForm.iSimplifiedDenominator = iDenominator/iGreatCommDivisor;

How do I check if file exists in jQuery or pure JavaScript?

What you'd have to do is send a request to the server for it to do the check, and then send back the result to you.

What type of server are you trying to communicate with? You may need to write a small service to respond to the request.

POST data in JSON format

Using the new FormData object (and other ES6 stuff), you can do this to turn your entire form into JSON:

let data = {};
let formdata = new FormData(theform);
for (let tuple of formdata.entries()) data[tuple[0]] = tuple[1];

and then just xhr.send(JSON.stringify(data)); like in Jan's original answer.

Django - Did you forget to register or load this tag?

{% load static %}

Please add this template tag on top of the HTML or base HTML file

How can I programmatically generate keypress events in C#?

To produce key events without Windows Forms Context, We can use the following method,

public static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, uint dwExtraInfo);

sample code is given below:

const int VK_UP = 0x26; //up key
const int VK_DOWN = 0x28;  //down key
const int VK_LEFT = 0x25;
const int VK_RIGHT = 0x27;
const uint KEYEVENTF_KEYUP = 0x0002;
const uint KEYEVENTF_EXTENDEDKEY = 0x0001;
int press()
    //Press the key
    keybd_event((byte)VK_UP, 0, KEYEVENTF_EXTENDEDKEY | 0, 0);
    return 0;

List of Virtual Keys are defined here.

To get the complete picture, please use the below link,

Preferred way of loading resources in Java

Well, it partly depends what you want to happen if you're actually in a derived class.

For example, suppose SuperClass is in A.jar and SubClass is in B.jar, and you're executing code in an instance method declared in SuperClass but where this refers to an instance of SubClass. If you use this.getClass().getResource() it will look relative to SubClass, in B.jar. I suspect that's usually not what's required.

Personally I'd probably use Foo.class.getResourceAsStream(name) most often - if you already know the name of the resource you're after, and you're sure of where it is relative to Foo, that's the most robust way of doing it IMO.

Of course there are times when that's not what you want, too: judge each case on its merits. It's just the "I know this resource is bundled with this class" is the most common one I've run into.

How to set up Spark on Windows?

The guide by Ani Menon (thx!) almost worked for me on windows 10, i just had to get a newer winutils.exe off that git (currently hadoop-2.8.1):

<Django object > is not JSON serializable

Our js-programmer asked me to return the exact JSON format data instead of a json-encoded string to her.

Below is the solution.(This will return an object that can be used/viewed straightly in the browser)

import json
from xxx.models import alert
from django.core import serializers

def test(request):
    alert_list = alert.objects.all()

    tmpJson = serializers.serialize("json",alert_list)
    tmpObj = json.loads(tmpJson)

    return HttpResponse(json.dumps(tmpObj))

Why can't I define a default constructor for a struct in .NET?

You can make a static property that initializes and returns a default "rational" number:

public static Rational One => new Rational(0, 1); 

And use it like:

var rat = Rational.One;

Excel VBA, How to select rows based on data in a column?

Yes using Option Explicit is a good habit. Using .Select however is not :) it reduces the speed of the code. Also fully justify sheet names else the code will always run for the Activesheet which might not be what you actually wanted.

Is this what you are trying?

Option Explicit

Sub Sample()
    Dim lastRow As Long, i As Long
    Dim CopyRange As Range

    '~~> Change Sheet1 to relevant sheet name
    With Sheets("Sheet1")
        lastRow = .Range("A" & .Rows.Count).End(xlUp).Row

        For i = 2 To lastRow
            If Len(Trim(.Range("A" & i).Value)) <> 0 Then
                If CopyRange Is Nothing Then
                    Set CopyRange = .Rows(i)
                    Set CopyRange = Union(CopyRange, .Rows(i))
                End If
                Exit For
            End If

        If Not CopyRange Is Nothing Then
            '~~> Change Sheet2 to relevant sheet name
            CopyRange.Copy Sheets("Sheet2").Rows(1)
        End If
    End With
End Sub


If if you have data from Row 2 till Row 10 and row 11 is blank and then you have data again from Row 12 then the above code will only copy data from Row 2 till Row 10

If you want to copy all rows which have data then use this code.

Option Explicit

Sub Sample()
    Dim lastRow As Long, i As Long
    Dim CopyRange As Range

    '~~> Change Sheet1 to relevant sheet name
    With Sheets("Sheet1")
        lastRow = .Range("A" & .Rows.Count).End(xlUp).Row

        For i = 2 To lastRow
            If Len(Trim(.Range("A" & i).Value)) <> 0 Then
                If CopyRange Is Nothing Then
                    Set CopyRange = .Rows(i)
                    Set CopyRange = Union(CopyRange, .Rows(i))
                End If
            End If

        If Not CopyRange Is Nothing Then
            '~~> Change Sheet2 to relevant sheet name
            CopyRange.Copy Sheets("Sheet2").Rows(1)
        End If
    End With
End Sub

Hope this is what you wanted?


How do you access the value of an SQL count () query in a Java program

The answers provided by Bohzo and Brabster will obviously work, but you could also just use:


to get the value in the first, and in your case, only column.

Android ADB commands to get the device properties

adb shell getprop

If you want to see the whole list of parameters just type:

adb shell getprop

How to check if a string contains an element from a list in Python

This is a variant of the list comprehension answer given by @psun.

By switching the output value, you can actually extract the matching pattern from the list comprehension (something not possible with the any() approach by @Lauritz-v-Thaulow)

extensionsToCheck = ['.pdf', '.doc', '.xls']
url_string = 'http://.../foo.doc'

print [extension for extension in extensionsToCheck if(extension in url_string)]


You can furthermore insert a regular expression if you want to collect additional information once the matched pattern is known (this could be useful when the list of allowed patterns is too long to write into a single regex pattern)

print ['(\w+)'+extension, url_string).group(0) for extension in extensionsToCheck if(extension in url_string)]


Print Combining Strings and Numbers

The other answers explain how to produce a string formatted like in your example, but if all you need to do is to print that stuff you could simply write:

first = 10
second = 20
print "First number is", first, "and second number is", second

What is the difference between a "line feed" and a "carriage return"?

Both of these are primary from the old printing days.

Carriage return is from the days of the teletype printers/old typewriters, where literally the carriage would return to the next line, and push the paper up. This is what we now call \r.

Line feed LF signals the end of the line, it signals that the line has ended - but doesn't move the cursor to the next line. In other words, it doesn't "return" the cursor/printer head to the next line.

For more sundry details, the mighty wikipedia to the rescue.

Selecting multiple columns in a Pandas dataframe

You can use Pandas.

I create the DataFrame:

import pandas as pd
df = pd.DataFrame([[1, 2,5], [5,4, 5], [7,7, 8], [7,6,9]],
                  index=['Jane', 'Peter','Alex','Ann'],
                  columns=['Test_1', 'Test_2', 'Test_3'])

The DataFrame:

       Test_1  Test_2  Test_3
Jane        1       2       5
Peter       5       4       5
Alex        7       7       8
Ann         7       6       9

To select one or more columns by name:

df[['Test_1', 'Test_3']]

       Test_1  Test_3
Jane        1       5
Peter       5       5
Alex        7       8
Ann         7       9

You can also use:


And you get column Test_2:

Jane     2
Peter    4
Alex     7
Ann      6

You can also select columns and rows from these rows using .loc(). This is called "slicing". Notice that I take from column Test_1 to Test_3:

df.loc[:, 'Test_1':'Test_3']

The "Slice" is:

       Test_1  Test_2  Test_3
Jane        1       2       5
Peter       5       4       5
Alex        7       7       8
Ann         7       6       9

And if you just want Peter and Ann from columns Test_1 and Test_3:

df.loc[['Peter', 'Ann'], ['Test_1', 'Test_3']]

You get:

       Test_1  Test_3
Peter       5       5
Ann         7       9

How to dynamically create CSS class in JavaScript and apply?

I was looking through some of the answers here, and I couldn't find anything that automatically adds a new stylesheet if there are none, and if not simply modifies an existing one that already contains the style needed, so I made a new function (should work accross all browsers, though not tested, uses addRule and besides that only basic native JavaScript, let me know if it works):

function myCSS(data) {
    var head = document.head || document.getElementsByTagName("head")[0];
    if(head) {
        if(data && data.constructor == Object) {
            for(var k in data) {
                var selector = k;
                var rules = data[k];

                var allSheets = document.styleSheets;
                var cur = null;

                var indexOfPossibleRule = null,
                    indexOfSheet = null;
                for(var i = 0; i < allSheets.length; i++) {
                    indexOfPossibleRule = findIndexOfObjPropInArray("selectorText",selector,allSheets[i].cssRules);
                    if(indexOfPossibleRule != null) {
                        indexOfSheet = i;

                var ruleToEdit = null;
                if(indexOfSheet != null) {

                    ruleToEdit = allSheets[indexOfSheet].cssRules[indexOfPossibleRule];

                } else {
                    cur = document.createElement("style");
                    cur.type =  "text/css";
                    ruleToEdit = cur.sheet.cssRules[0];
                    console.log("NOPE, but here's a new one:", cur);
                applyCustomCSSruleListToExistingCSSruleList(rules, ruleToEdit, (err) => {
                    if(err) {
                    } else {
                        console.log("successfully added ", rules, " to ", ruleToEdit);
        } else {
            console.log("provide one paramter as an object containing the cssStyles, like: {\"#myID\":{position:\"absolute\"}, \".myClass\":{background:\"red\"}}, etc...");
    } else {
        console.log("run this after the page loads");


then just add these 2 helper functions either inside the above function, or anywhere else:

function applyCustomCSSruleListToExistingCSSruleList(customRuleList, existingRuleList, cb) {
    var err = null;
    console.log("trying to apply ", customRuleList, " to ", existingRuleList);
    if(customRuleList && customRuleList.constructor == Object && existingRuleList && existingRuleList.constructor == CSSStyleRule) {
        for(var k in customRuleList) {
            existingRuleList["style"][k] = customRuleList[k];

    } else {
        err = ("provide first argument as an object containing the selectors for the keys, and the second argument is the CSSRuleList to modify");
    if(cb) {

function findIndexOfObjPropInArray(objPropKey, objPropValue, arr) {
    var index = null;
    for(var i = 0; i < arr.length; i++) {
        if(arr[i][objPropKey] == objPropValue) {
            index = i;
    return index;

(notice that in both of them I use a for loop instead of .filter, since the CSS style / rule list classes only have a length property, and no .filter method.)

Then to call it:

    "#coby": {
    ".myError": {

Let me know if it works for your browser or gives an error.

Best practices for API versioning?

We found it practical and useful to put the version in the URL. It makes it easy to tell what you're using at a glance. We do alias /foo to /foo/(latest versions) for ease of use, shorter / cleaner URLs, etc, as the accepted answer suggests.

Keeping backwards compatibility forever is often cost-prohibitive and/or very difficult. We prefer to give advanced notice of deprecation, redirects like suggested here, docs, and other mechanisms.

How do I lock the orientation to portrait mode in a iPhone Web Application?

Maybe in a new future it will have an out-of-the-box soludion...

As for May 2015,

there is an experimental functionality that does that.

But it only works on Firefox 18+, IE11+, and Chrome 38+.

However, it does not work on Opera or Safari yet.

Here is the current code for the compatible browsers:

var lockOrientation = screen.lockOrientation || screen.mozLockOrientation || screen.msLockOrientation;


Select rows of a matrix that meet a condition

I will choose a simple approach using the dplyr package.

If the dataframe is data.

result <- filter(data, three == 11)

Which header file do you include to use bool type in c in linux?

bool is just a macro that expands to _Bool. You can use _Bool with no #include very much like you can use int or double; it is a C99 keyword.

The macro is defined in <stdbool.h> along with 3 other macros.

The macros defined are

  • bool: macro expands to _Bool
  • false: macro expands to 0
  • true: macro expands to 1
  • __bool_true_false_are_defined: macro expands to 1

Best way to reverse a string

If someone asks about string reverse, the intension could be to find out whether you know any bitwise operation like XOR. In C# you have Array.Reverse function, however, you can do using simple XOR operation in few lines of code(minimal)

    public static string MyReverse(string s)
        char[] charArray = s.ToCharArray();
        int bgn = -1;
        int end = s.Length;
        while(++bgn < --end)
            charArray[bgn] ^= charArray[end];
            charArray[end] ^= charArray[bgn];
            charArray[bgn] ^= charArray[end];
        return new string(charArray);

Split an NSString to access one particular piece

NSArray* foo = [@"10/04/2011" componentsSeparatedByString: @"/"];
NSString* firstBit = [foo objectAtIndex: 0];

Update 7/3/2018:

Now that the question has acquired a Swift tag, I should add the Swift way of doing this. It's pretty much as simple:

let substrings = "10/04/2011".split(separator: "/")
let firstBit = substrings[0]

Although note that it gives you an array of Substring. If you need to convert these back to ordinary strings, use map

let strings = "10/04/2011".split(separator: "/").map{ String($0) }
let firstBit = strings[0]


let firstBit = String(substrings[0])

Convert Uri to String and String to Uri

I am not sure if you got this resolved. To follow up on "CommonsWare's" comment.

That is not a valid string representation of a Uri. A Uri has a scheme, and "/external/images/media/470939" does not have a scheme.


Uri uri=Uri.parse("/external/images/media/470939");


Uri uri=Uri.parse("content://external/images/media/470939");

in my case

Uri uri = Uri.parse("content://media/external/images/media/6562");

PHPMailer: SMTP Error: Could not connect to SMTP host

I recently dealt with this problem, and the cause of the problem turned out to be that the root certificate on the SMTP server that I was connecting to was the Sectigo root certificate that recently expired.

If you're connecting to the SMTP server by SSL/TLS or STARTTLS, and you've not changed anything recently in the environment where your PHPMailer script is running, and this problem suddenly occurred - then you might want to check for an expired or invalid certificate somewhere in the certificate chain on the server.

You can view the server's certificate chain using openssl s_client.

For SSL/TLS on port 465:

openssl s_client -connect server.domain.tld:465 | openssl x509 -text

For STARTTLS on port 587:

openssl s_client -starttls smtp -crlf -connect server.domain.tld:587 | openssl x509 -text

How to add a new line of text to an existing file in Java?

Starting from Java 7:

Define a path and the String containing the line separator at the beginning:

Path p = Paths.get("C:\\Users\\first.last\\test.txt");
String s = System.lineSeparator() + "New Line!";

and then you can use one of the following approaches:

  1. Using Files.write (small files):

    try {
        Files.write(p, s.getBytes(), StandardOpenOption.APPEND);
    } catch (IOException e) {
  2. Using Files.newBufferedWriter(text files):

    try (BufferedWriter writer = Files.newBufferedWriter(p, StandardOpenOption.APPEND)) {
    } catch (IOException ioe) {
        System.err.format("IOException: %s%n", ioe);
  3. Using Files.newOutputStream (interoperable with APIs):

    try (OutputStream out = new BufferedOutputStream(Files.newOutputStream(p, StandardOpenOption.APPEND))) {
    } catch (IOException e) {
  4. Using Files.newByteChannel (random access files):

    try (SeekableByteChannel sbc = Files.newByteChannel(p, StandardOpenOption.APPEND)) {
    } catch (IOException e) {
  5. Using (random access files):

    try (FileChannel sbc =, StandardOpenOption.APPEND)) {
    } catch (IOException e) {

Details about these methods can be found in the Oracle's tutorial.

How to pass in a react component into another react component to transclude the first component's content?

Note I provided a more in-depth answer here

Runtime wrapper:

It's the most idiomatic way.

const Wrapper = ({children}) => (

const App = () => <div>Hello</div>;

const WrappedApp = () => (

Note that children is a "special prop" in React, and the example above is syntactic sugar and is (almost) equivalent to <Wrapper children={<App/>}/>

Initialization wrapper / HOC

You can use an Higher Order Component (HOC). They have been added to the official doc recently.

// Signature may look fancy but it's just 
// a function that takes a component and returns a new component
const wrapHOC = (WrappedComponent) => (props) => (
    <div><WrappedComponent {...props}/></div>

const App = () => <div>Hello</div>;

const WrappedApp = wrapHOC(App);

This can lead to (little) better performances because the wrapper component can short-circuit the rendering one step ahead with shouldComponentUpdate, while in the case of a runtime wrapper, the children prop is likely to always be a different ReactElement and cause re-renders even if your components extend PureComponent.

Notice that connect of Redux used to be a runtime wrapper but was changed to an HOC because it permits to avoid useless re-renders if you use the pure option (which is true by default)

You should never call an HOC during the render phase because creating React components can be expensive. You should rather call these wrappers at initialization.

Note that when using functional components like above, the HOC version do not provide any useful optimisation because stateless functional components do not implement shouldComponentUpdate

More explanations here:

Changing case in Vim

Visual select the text, then U for uppercase or u for lowercase. To swap all casing in a visual selection, press ~ (tilde).

Without using a visual selection, gU<motion> will make the characters in motion uppercase, or use gu<motion> for lowercase.

For more of these, see Section 3 in Vim's change.txt help file.

Where is the web server root directory in WAMP?

To check what is your root directory go to httpd.conf file of apache and search for "DocumentRoot".The location following it is your root directory

How to write "Html.BeginForm" in Razor

The following code works fine:

@using (Html.BeginForm("Upload", "Upload", FormMethod.Post, 
                                      new { enctype = "multipart/form-data" }))
        Select a file <input type="file" name="file" />
        <input type="submit" value="Upload" />

and generates as expected:

<form action="/Upload/Upload" enctype="multipart/form-data" method="post">    
        Select a file <input type="file" name="file" />
        <input type="submit" value="Upload" />

On the other hand if you are writing this code inside the context of other server side construct such as an if or foreach you should remove the @ before the using. For example:

@if (SomeCondition)
    using (Html.BeginForm("Upload", "Upload", FormMethod.Post, 
                                      new { enctype = "multipart/form-data" }))
            Select a file <input type="file" name="file" />
            <input type="submit" value="Upload" />

As far as your server side code is concerned, here's how to proceed:

public ActionResult Upload(HttpPostedFileBase file) 
    if (file != null && file.ContentLength > 0) 
        var fileName = Path.GetFileName(file.FileName);
        var path = Path.Combine(Server.MapPath("~/content/pics"), fileName);
    return RedirectToAction("Upload");

Does Android keep the .apk files? if so where?

You can pull apps with ADB. They are in /data/App/, I believe.

adb pull (location on device) (where to save)

Note that you have to root your phone to pull copy protected apps.

yii2 hidden input value

Hello World!
You see, the main question while using hidden input is what kind of data you want to pass? I will assume that you are trying to pass the user ID.
Which is not a really good idea to pass it here because field() method will generate input and the value will be shown to user as we can't hide html from the users browser. This if you really care about security of your website.

please check this link, and you will see that it's impossible to hide value attribute from users to see.

so what to do then?

See, this is the core of OOP in PHP. and I quote from Matt Zandstr in his great book PHP Objects, Patterns, and Practice fifth edition

I am still stuck with a great deal of unwanted flexibility, though. I rely on the client coder to change a ShopProduct object’s properties from their default values. This is problematic in two ways. First, it takes five lines to properly initialize a ShopProduct object, and no coder will thank you for that. Second, I have no way of ensuring that any of the properties are set when a ShopProduct object is initialized. What I need is a method that is called automatically when an object is instantiated from a class.

Please check this example of using __construct() method which is mentioned in his book too.

     class ShopProduct { 
       public $title;   
       public $producerMainName;  
       public $producerFirstName;  
       public $price = 0;
       public function __construct($title,$firstName,$mainName,$price) {
            $this->title = $title;
            $this->producerFirstName = $firstName;  
            $this->producerMainName = $mainName; 
            $this->price = $price;

And you can simply do this magic.

$product1 = new ShopProduct("My Antonia","Willa","Cather",5.99 );
print "author: {$product1->getProducer()}\n";

This produces the following:

author: Willa Cather

In your case it will be something semilar to this, every time you create an object just pass the user ID to the user_id property, and save yourself a lot of coding.

Class Car {
  private $user_id;
//.. your properties

  public function __construct($title,$firstName,$mainName,$price){
     $this->user_id = \Yii::$app->user->id;
    //..Your magic


Good luck! And Happy Coding!

Usage of sys.stdout.flush() method

import sys
for x in range(10000):
    print "HAPPY >> %s <<\r" % str(x),

How can I view an object with an alert()

alert( JSON.stringify(product) );

Implementing multiple interfaces with Java - is there a way to delegate?

There's no pretty way. You might be able to use a proxy with the handler having the target methods and delegating everything else to them. Of course you'll have to use a factory because there'll be no constructor.

Why does this iterative list-growing code give IndexError: list assignment index out of range?

You could use a dictionary (similar to an associative array) for j

i = [1, 2, 3, 5, 8, 13]
j = {} #initiate as dictionary
k = 0

for l in i:
    j[k] = l
    k += 1


will print :

{0: 1, 1: 2, 2: 3, 3: 5, 4: 8, 5: 13}

Abstraction vs Encapsulation in Java

Abstraction is about identifying commonalities and reducing features that you have to work with at different levels of your code.

e.g. I may have a Vehicle class. A Car would derive from a Vehicle, as would a Motorbike. I can ask each Vehicle for the number of wheels, passengers etc. and that info has been abstracted and identified as common from Cars and Motorbikes.

In my code I can often just deal with Vehicles via common methods go(), stop() etc. When I add a new Vehicle type later (e.g. Scooter) the majority of my code would remain oblivious to this fact, and the implementation of Scooter alone worries about Scooter particularities.

Why did a network-related or instance-specific error occur while establishing a connection to SQL Server?

If you are connecting from Windows Machine A to Windows Machine B (server with SQL Server installed) and are getting this error, you need to do the following:

On Machine B:

  1. Turn on the Windows service called "SQL Server Browser" and start the service Windows Services
  2. In Windows Firewall:
    • enable incoming port UDP 1434 (in case SQL Server Management Studio on machine A is connecting or a program on machine A is connecting)
    • enable incoming port TCP 1433 (in case there is a telnet connection) Windows firewall
  3. In SQL Server Configuration Manager:
    • enable TCP/IP protocol for port 1433 Sql Server Configuration Manager

Create dataframe from a matrix

Using dplyr and tidyr:


df <- as_data_frame(mat) %>%      # convert the matrix to a data frame
  gather(name, val, C_0:C_1) %>%  # convert the data frame from wide to long
  select(name, time, val)         # reorder the columns

# A tibble: 6 x 3
   name  time   val
  <chr> <dbl> <dbl>
1   C_0   0.0   0.1
2   C_0   0.5   0.2
3   C_0   1.0   0.3
4   C_1   0.0   0.3
5   C_1   0.5   0.4
6   C_1   1.0   0.5

how to pass parameter from @Url.Action to controller function

This way to pass value from Controller to View:

ViewData["ID"] = _obj.ID;

Here is the way to pass value from View to Controller back:

<input type="button" title="Next" value="Next Step" onclick="location.href='@Url.Action("CreatePerson", "Person", new { ID = ViewData["ID"] })'" />

Groovy method with optional parameters

Can't be done as it stands... The code

def myMethod(pParm1='1', pParm2='2'){
    println "${pParm1}${pParm2}"

Basically makes groovy create the following methods:

Object myMethod( pParm1, pParm2 ) {
    println "$pParm1$pParm2"

Object myMethod( pParm1 ) {
    this.myMethod( pParm1, '2' )

Object myMethod() {
    this.myMethod( '1', '2' )

One alternative would be to have an optional Map as the first param:

def myMethod( Map map = [:], String mandatory1, String mandatory2 ){
    println "${mandatory1} ${mandatory2} ${map.parm1 ?: '1'} ${map.parm2 ?: '2'}"

myMethod( 'a', 'b' )                // prints 'a b 1 2'
myMethod( 'a', 'b', parm1:'value' ) // prints 'a b value 2'
myMethod( 'a', 'b', parm2:'2nd')    // prints 'a b 1 2nd'

Obviously, documenting this so other people know what goes in the magical map and what the defaults are is left to the reader ;-)

Hide particular div onload and then show div after click

Make sure to watch your selectors. You appear to have forgotten the # for div2. Additionally, you can toggle the visibility of many elements at once with .toggle():

// Short-form of `document.ready`
    $("#preview").on("click", function(){
        $("#div1, #div2").toggle();


Click toggle with jQuery

I have a single checkbox named chkDueDate and an HTML object with a click event as follows:

$('#chkDueDate').attr('checked', !$('#chkDueDate').is(':checked'));

Clicking the HTML object (in this case a <span>) toggles the checked property of the checkbox.

How to insert 1000 rows at a time

You can of course use a loop, or you can insert them in a single statement, e.g.

Insert into db

It really depends where you're getting your data from.

If you use a loop, wrapping it in a transaction will make it a bit faster.


What if i want to insert unique names?

If you want to insert unique names, then you need to generate data with unique names. One way to do this is to use Visual Studio to generate test data.

What does 'index 0 is out of bounds for axis 0 with size 0' mean?

Essentially it means you don't have the index you are trying to reference. For example:

df = pd.DataFrame()
df['data'][0]=5 #I haven't yet assigned how long df[data] should be!

will give me the error you are referring to, because I haven't told Pandas how long my dataframe is. Whereas if I do the exact same code but I DO assign an index length, I don't get an error:

df = pd.DataFrame(index=[0,1,2,3,4])
df['data'][0]=5 #since I've properly labelled my index, I don't run into this problem!

Hope that answers your question!

Shell script to capture Process ID and kill it if exist

I use the command pkill for this:

       pgrep, pkill - look up or signal processes based on name and 
       other attributes

       pgrep [options] pattern
       pkill [options] pattern

       pgrep looks through the currently running processes and lists 
       the process IDs which match the selection criteria to stdout.
       All the criteria have to match.  For example,

              $ pgrep -u root sshd

       will only list the processes called sshd AND owned by root.
       On the other hand,

              $ pgrep -u root,daemon

       will list the processes owned by root OR daemon.

       pkill will send the specified signal (by default SIGTERM) 
       to each process instead of listing them on stdout.

If your code runs via interpreter (java, python, ...) then the name of the process is the name of the interpreter. You need to user the argument --full. This matches against the command name and the arguments.

How to Convert Datetime to Date in dd/MM/yyyy format

Give a different alias

SELECT  Convert(varchar,A.InsertDate,103) as converted_Tran_Date from table as A
order by A.InsertDate 

What is a regular expression for a MAC Address?

If you need spaces between numbers, like this variant

3D : F2 : C9 : A6 : B3 : 4F

The regex changes to


Padding between ActionBar's home icon and title

I had a similar issue but with spacing between the up and the custom app icon/logo in the action bar. Dushyanth's solution of setting padding programatically worked for me (setting padding on app/logo icon). I tried to find either or (ActionBarSherlock only, as this ensures backwards compatibility), and it seems to work across 2.3-4.3 devices I've tested on.

Git On Custom SSH Port

git clone ssh://[email protected]:[port]/gitolite-admin

Note that the port number should be there without the square brackets: []

How to change text color of cmd with windows batch script every 1 second

echo off & cls
title   never buy these they're so easy to make... hmu for source code             

color 0D

echo =================================================================
echo i flex on my unhittable ovh, you flex on an easy to hit trash ovh
echo =================================================================
set /p IP=Enter IP:
title :: this skid's boutta get slammed FeelsGoodMan ::    -%pinging:IP%-
PING -n 1 %IP% | FIND "TTL="
IF ERRORLEVEL (echo stop flexing on ovh's i down them with ease, mine on the other hand is unhittable.):
set /a num=(%Random%%%9)+1
color %num%IP   ping -t 2 0 10 >nul
GoTo top

This is an ip pinging that has custom timed out messages for if something such as a website or server is down, also, can use for if booting people offline, I can make a tool that opens files and individual pingers dependant on your input, and a built in geo-location tool.

How to append rows to an R data frame

A more generic solution for might be the following.

    extendDf <- function (df, n) {
    withFactors <- sum(sapply (df, function(X) (is.factor(X)) )) > 0
    nr          <- nrow (df)
    colNames    <- names(df)
    for (c in 1:length(colNames)) {
        if (is.factor(df[,c])) {
            col         <- vector (mode='character', length = nr+n) 
            col[1:nr]   <- as.character(df[,c])
            col[(nr+1):(n+nr)]<- rep(col[1], n)  # to avoid extra levels
            col         <- as.factor(col)
        } else {
            col         <- vector (mode=mode(df[1,c]), length = nr+n)
            class(col)  <- class (df[1,c])
            col[1:nr]   <- df[,c] 
        if (c==1) {
            newDf       <- data.frame (col ,stringsAsFactors=withFactors)
        } else {
            newDf[,c]   <- col 
    names(newDf) <- colNames

The function extendDf() extends a data frame with n rows.

As an example:

aDf <- data.frame (l=TRUE, i=1L, n=1, c='a', t=Sys.time(), stringsAsFactors = TRUE)
extendDf (aDf, 2)
#      l i n c                   t
# 1  TRUE 1 1 a 2016-07-06 17:12:30
# 2 FALSE 0 0 a 1970-01-01 01:00:00
# 3 FALSE 0 0 a 1970-01-01 01:00:00

system.time (eDf <- extendDf (aDf, 100000))
#    user  system elapsed 
#   0.009   0.002   0.010
system.time (eDf <- extendDf (eDf, 100000))
#    user  system elapsed 
#   0.068   0.002   0.070

Android: adb pull file on desktop

Use a fully-qualified path to the desktop (e.g., /home/mmurphy/Desktop).

Example: adb pull sdcard/log.txt /home/mmurphy/Desktop

Getting the first index of an object

If the order of the objects is significant, you should revise your JSON schema to store the objects in an array:

    {"name":"foo", ...},
    {"name":"bar", ...},
    {"name":"baz", ...}

or maybe:

    ["foo", {}],
    ["bar", {}],
    ["baz", {}]

As Ben Alpert points out, properties of Javascript objects are unordered, and your code is broken if you expect them to enumerate in the same order that they are specified in the object literal—there is no "first" property.

Copy files from one directory into an existing directory

What you want is:

cp -R t1/. t2/

The dot at the end tells it to copy the contents of the current directory, not the directory itself. This method also includes hidden files and folders.

WAMP Cannot access on local network 403 Forbidden

For Apache 2.4.9

in addition, look at the httpd-vhosts.conf file in C:\wamp\bin\apache\apache2.4.9\conf\extra

<VirtualHost *:80>
ServerName localhost
ServerAlias localhost
DocumentRoot C:/wamp/www
<Directory "C:/wamp/www/">
Options Indexes FollowSymLinks MultiViews
AllowOverride all
Require local

Change to:

<VirtualHost *:80>
ServerName localhost
ServerAlias localhost
DocumentRoot C:/wamp/www
<Directory "C:/wamp/www/">
Options Indexes FollowSymLinks MultiViews
AllowOverride all
Require all granted

changing from "Require local" to "Require all granted" solved the error 403 in my local network

How to run batch file from network share without "UNC path are not supported" message?

I needed to be able to just Windows Explorer browse through the server share, then double-click launch the batch file. @dbenham led me to an easier solution for my scenario (without the popd worries):

:: Capture UNC or mapped-drive path script was launched from
set NetPath=%~dp0

:: Assumes that setup.exe is in the same UNC path

:: Note that NetPath has a trailing backslash ("\")
robocopy.exe "%NetPath%Custom" /copyall "C:\Program Files (x86)\WP\Custom Templates"
Regedit.exe /s %NetPath%..\WPX5\Custom\Migrate.reg

:: I am not sure if WPX5 was typo, so use ".." for parent directory
set NetPath=

"&" meaning after variable type

The & means that the function accepts the address (or reference) to a variable, instead of the value of the variable.

For example, note the difference between this:

void af(int& g)

int main()
    int g = 123;
    cout << g;
    cout << g;
    return 0;

And this (without the &):

void af(int g)

int main()
    int g = 123;
    cout << g;
    cout << g;
    return 0;

Switch statement with returns -- code correctness

I'd normally write the code without them. IMO, dead code tends to indicate sloppiness and/or lack of understanding.

Of course, I'd also consider something like:

char const *rets[] = {"blah", "foo", "bar"};

return rets[something];

Edit: even with the edited post, this general idea can work fine:

char const *rets[] = { "blah", "foo", "bar", "bar", "foo"};

if ((unsigned)something < 5)
    return rets[something]
return "foobar";

At some point, especially if the input values are sparse (e.g., 1, 100, 1000 and 10000), you want a sparse array instead. You can implement that as either a tree or a map reasonably well (though, of course, a switch still works in this case as well).

Activity transition in Android

Yes. You can tell the OS what kind of transition you want to have for your activity.

public void onCreate(Bundle savedInstanceState)



Where ANIMATION is an integer referring to a built in animation in the OS.

Trim to remove white space

No need for jQuery

JavaScript does have a native .trim() method.

var name = "    John Smith  ";
name = name.trim();

console.log(name); // "John Smith"

Example Here


The trim() method removes whitespace from both ends of a string. Whitespace in this context is all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator characters (LF, CR, etc.).

ValueError: Length of values does not match length of index | Pandas DataFrame.unique()

The error comes up when you are trying to assign a list of numpy array of different length to a data frame, and it can be reproduced as follows:

A data frame of four rows:

df = pd.DataFrame({'A': [1,2,3,4]})

Now trying to assign a list/array of two elements to it:

df['B'] = [3,4]   # or df['B'] = np.array([3,4])

Both errors out:

ValueError: Length of values does not match length of index

Because the data frame has four rows but the list and array has only two elements.

Work around Solution (use with caution): convert the list/array to a pandas Series, and then when you do assignment, missing index in the Series will be filled with NaN:

df['B'] = pd.Series([3,4])

#   A     B
#0  1   3.0
#1  2   4.0
#2  3   NaN          # NaN because the value at index 2 and 3 doesn't exist in the Series
#3  4   NaN

For your specific problem, if you don't care about the index or the correspondence of values between columns, you can reset index for each column after dropping the duplicates:

df.apply(lambda col: col.drop_duplicates().reset_index(drop=True))

#   A     B
#0  1   1.0
#1  2   5.0
#2  7   9.0
#3  8   NaN

Android 'Unable to add window -- token null is not for an application' exception

I solved this error by add below user-permission in AndroidManifest.xml

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

Also, Initialize Alert dialog with Activity Name:

AlertDialog.Builder builder = new AlertDialog.Builder(YourActivity.this);

For More Details, visit==> How to create Alert Dialog in Android

R - test if first occurrence of string1 is followed by string2

> grepl("^[^_]+_1",s)
> grepl("^[^_]+_2",s)
[1] TRUE

basically, look for everything at the beginning except _, and then the _2.

+1 to @Ananda_Mahto for suggesting grepl instead of grep.

how to customise input field width in bootstrap 3

You can use these classes





for input fields and replace input with btn for buttons.

Check this documentation

This will change only height of the element, to reduce the width you have to use grid system classes like col-xs-* col-md-* col-lg-*.

Example col-md-3. See doc here

Cannot find Microsoft.Office.Interop Visual Studio

I think you need to run that .msi to install the dlls. After I ran that .msi I can go to (VS 2012) Add References > Assemblies > Extensions and all of the Microsoft.Office.Interop dlls are there.

On my computer the dlls are found in "c:\Program Files(x86)\Microsoft Visual Studio 12.0\Visual Studio Tools for Office\PIA" so you could check in a similar/equivalent directory on yours just to make sure they're not there?

How to write data with FileOutputStream without losing old data?

Use the constructor for appending material to the file:

FileOutputStream(File file, boolean append)
Creates a file output stream to write to the file represented by the specified File object.

So to append to a file say "abc.txt" use

FileOutputStream fos=new FileOutputStream(new File("abc.txt"),true);

MySQL select rows where left join is null

Here is a query that returns only the rows where no correspondance has been found in both columns user_one and user_two of table2:

FROM table1 T1
LEFT OUTER JOIN table2 T2A ON T2A.user_one =
LEFT OUTER JOIN table2 T2B ON T2B.user_two =
WHERE T2A.user_one IS NULL
    AND T2B.user_two IS NULL

There is one jointure for each column (user_one and user_two) and the query only returns rows that have no matching jointure.

Hope this will help you.

Swift - Integer conversion to Hours/Minutes/Seconds

Here is another simple implementation in Swift3.

func seconds2Timestamp(intSeconds:Int)->String {
   let mins:Int = intSeconds/60
   let hours:Int = mins/60
   let secs:Int = intSeconds%60

   let strTimestamp:String = ((hours<10) ? "0" : "") + String(hours) + ":" + ((mins<10) ? "0" : "") + String(mins) + ":" + ((secs<10) ? "0" : "") + String(secs)
   return strTimestamp

How to have a default option in Angular.js select box

try this in your angular controller...

$somethingHere = {name: 'Something Cool'};

You can set a value, but you are using a complex type and the angular will search key/value to set in your view.

And, if does not work, try this : ng-options="option.value as for option in options track by"

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

The simplest approach I found on Mac OS X was to use the rename package from

brew install rename
rename --force --lower-case --nows *

--force Rename even when a file with the destination name already exists.

--lower-case Convert file names to all lower case.

--nows Replace all sequences of whitespace in the filename with single underscore characters.

How can I display the users profile pic using the facebook graph api?

to get different sizes, you can use the type parameter:

You can specify the picture size you want with the type argument, which should be one of square (50x50), small (50 pixels wide, variable height), and large (about 200 pixels wide, variable height):

See whether an item appears more than once in a database column

To expand on Solomon Rutzky's answer, if you are looking for a piece of data that shows up in a range (i.e. more than once but less than 5x), you can use

having count(*) > 1 and count(*) < 5

And you can use whatever qualifiers you desire in there - they don't have to match, it's all just included in the 'having' statement.

Number of processors/cores in command line

Another one-liner, without counting hyper-threaded cores:

lscpu | awk -F ":" '/Core/ { c=$2; }; /Socket/ { print c*$2 }' 


There is a great solution for this problem ,You can use the Merge Keyword of Sql

Merge MyTargetTable hba
USING (SELECT Id = 8, Name = 'Product Listing Message') temp 
ON temp.Id = hba.Id
WHEN NOT matched THEN 
INSERT (Id, Name) VALUES (temp.Id, temp.Name);

You can check this before following, below is the sample

IF OBJECT_ID ('dbo.TargetTable') IS NOT NULL
    DROP TABLE dbo.TargetTable

CREATE TABLE dbo.TargetTable
    Id   INT NOT NULL,
    Name VARCHAR (255) NOT NULL,

INSERT INTO dbo.TargetTable (Name)
VALUES ('Unknown')

INSERT INTO dbo.TargetTable (Name)
VALUES ('Mapping')

INSERT INTO dbo.TargetTable (Name)
VALUES ('Update')

INSERT INTO dbo.TargetTable (Name)
VALUES ('Message')

INSERT INTO dbo.TargetTable (Name)
VALUES ('Switch')

INSERT INTO dbo.TargetTable (Name)
VALUES ('Unmatched')

INSERT INTO dbo.TargetTable (Name)
VALUES ('ProductMessage')

Merge MyTargetTable hba
USING (SELECT Id = 8, Name = 'Listing Message') temp 
ON temp.Id = hba.Id
WHEN NOT matched THEN 
INSERT (Id, Name) VALUES (temp.Id, temp.Name);

How to use the ProGuard in Android Studio?

NB.: Now instead of

runProguard false

you'll need to use

minifyEnabled false

How to iterate over each string in a list of strings and operate on it's elements

Use range() instead, like the following :

for i in range(len(words)):

Spring: Returning empty HTTP Responses with ResponseEntity<Void> doesn't work

NOTE: This is true for the version mentioned in the question, 4.1.1.RELEASE.

Spring MVC handles a ResponseEntity return value through HttpEntityMethodProcessor.

When the ResponseEntity value doesn't have a body set, as is the case in your snippet, HttpEntityMethodProcessor tries to determine a content type for the response body from the parameterization of the ResponseEntity return type in the signature of the @RequestMapping handler method.

So for

public ResponseEntity<Void> taxonomyPackageExists( @PathVariable final String key ) {

that type will be Void. HttpEntityMethodProcessor will then loop through all its registered HttpMessageConverter instances and find one that can write a body for a Void type. Depending on your configuration, it may or may not find any.

If it does find any, it still needs to make sure that the corresponding body will be written with a Content-Type that matches the type(s) provided in the request's Accept header, application/xml in your case.

If after all these checks, no such HttpMessageConverter exists, Spring MVC will decide that it cannot produce an acceptable response and therefore return a 406 Not Acceptable HTTP response.

With ResponseEntity<String>, Spring will use String as the response body and find StringHttpMessageConverter as a handler. And since StringHttpMessageHandler can produce content for any media type (provided in the Accept header), it will be able to handle the application/xml that your client is requesting.

Spring MVC has since been changed to only return 406 if the body in the ResponseEntity is NOT null. You won't see the behavior in the original question if you're using a more recent version of Spring MVC.

In iddy85's solution, which seems to suggest ResponseEntity<?>, the type for the body will be inferred as Object. If you have the correct libraries in your classpath, ie. Jackson (version > 2.5.0) and its XML extension, Spring MVC will have access to MappingJackson2XmlHttpMessageConverter which it can use to produce application/xml for the type Object. Their solution only works under these conditions. Otherwise, it will fail for the same reason I've described above.

Check whether a string contains a substring

To find out if a string contains substring you can use the index function:

if (index($str, $substr) != -1) {
    print "$str contains $substr\n";

It will return the position of the first occurrence of $substr in $str, or -1 if the substring is not found.

Select max value of each group

select name, max(value)
from out_pumptable
group by name

How do I escape a string inside JavaScript code inside an onClick handler?

Declare separate functions in the <head> section and invoke those in your onClick method. If you have lots you could use a naming scheme that numbers them, or pass an integer in in your onClicks and have a big fat switch statement in the function.

Exporting data In SQL Server as INSERT INTO

Here is an example of creating a data migration script using a cursor to iterate the source table.

DECLARE @out nvarchar(max) = ''
DECLARE @row nvarchar(1024)
DECLARE @first int = 1

    SELECT '(' + CONVERT(CHAR(1),[Stage]) + ',''' + [Label] + ''')'
    ORDER BY [Stage]



OPEN cur
    INTO @row

    IF @first = 1
        SET @first = 0
        SET @out = @out + ',' + CHAR(13);

    SET @out = @out + @row

    FETCH NEXT FROM cur into @row


PRINT @out


"Parse Error : There is a problem parsing the package" while installing Android application

If you're compiling and exporting your apk file under SDK version 2.1, it will not work on any android version below your SDK export "2.1". Android software is forward compatible not backward compatible. For example if you're programming using the android NDK (ann add-on to the android SDK) package that allows development in the C/C++ family, this is only compatible with android 2.3, android version 2.2 and below support java builds only. Therefore you will reaceive the "There is a problem parsing the package" error.

How to Decode Json object in laravel and apply foreach loop on that in laravel

you can use json_decode function

foreach (json_decode($response) as $area)
 print_r($area); // this is your area from json response

See this fiddle

HTML5 video won't play in Chrome only

I had a similar issue, no videos would play in Chrome. Tried installing beta 64bit, going back to Chrome 32bit release.

The only thing that worked for me was updating my video drivers.

I have the NVIDIA GTS 240. Downloaded, installed the drivers and restarted and Chrome 38.0.2125.77 beta-m (64-bit) starting playing HTML5 videos again on youtube, vimeo and others. Hope this helps anyone else.

How to display raw html code in PRE or something like it but without escaping it

Essentially the original question can be broken down in 2 parts:

  • Main objective/challenge: embedding(/transporting) a raw formatted code-snippet (any kind of code) in a web-page's markup (for simple copy/paste/edit due to no encoding/escaping)
  • correctly displaying/rendering that code-snippet (possibly edit it) in the browser

The short (but) ambiguous answer is: you can't, ...but you can (get very close).
(I know, that are 3 contradicting answers, so read on...)

(polyglot)(x)(ht)ml Markup-languages rely on wrapping (almost) everything between begin/opening and end/closing tags/character(sequences).
So, to embed any kind of raw code/snippet inside your markup-language, one will always have to escape/encode every instance (inside that snippet) that resembles the character(-sequence) that would close the wrapping 'container' element in the markup. (During this post I'll refer to this as rule no 1.)
Think of "some "data" here" or <i>..close italics with '</i>'-tag</i>, where it is obvious one should escape/encode (something in) </i and " (or change container's quote-character from " to ').

So, because of rule no 1, you can't 'just' embed 'any' unknown raw code-snippet inside markup.
Because, if one has to escape/encode even one character inside the raw snippet, then that snippet would no longer be the same original 'pure raw code' that anyone can copy/paste/edit in the document's markup without further thought. It would lead to malformed/illegal markup and Mojibake (mainly) because of entities.
Also, should that snippet contain such characters, you'd still need some javascript to 'translate' that character(sequence) from (and to) it's escaped/encoded representation to display the snippet correctly in the 'webpage' (for copy/paste/edit).

That brings us to (some of) the datatypes that markup-languages specify. These datatypes essentially define what are considered 'valid characters' and their meaning (per tag, property, etc.):

  • PCDATA (Parsed Character DATA): will expand entities and one must escape <, & (and > depending on markup language/version).
    Most tags like body, div, pre, etc, but also textarea (until HTML5) fall under this type.
    So not only do you need to encode all the container's closing character-sequences inside the snippet, you also have to encode all <, & (,>) characters (at minimum).
    Needless to say, encoding/escaping this many characters falls outside this objective's scope of embedding a raw snippet in the markup.
    '..But a textarea seems to work...', yes, either because of the browsers error-engine trying to make something out of it, or because HTML5:

  • RCDATA (Replaceable Character DATA): will not not treat tags inside the text as markup (but are still governed by rule 1), so one doesn't need to encode < (>). BUT entities are still expanded, so they and 'ambiguous ampersands' (&) need special care.
    The current HTML5 spec says the textarea is now a RCDATA field and (quote):

    The text in raw text and RCDATA elements must not contain any occurrences of the string "</" (U+003C LESS-THAN SIGN, U+002F SOLIDUS) followed by characters that case-insensitively match the tag name of the element followed by one of U+0009 CHARACTER TABULATION (tab), U+000A LINE FEED (LF), U+000C FORM FEED (FF), U+000D CARRIAGE RETURN (CR), U+0020 SPACE, U+003E GREATER-THAN SIGN (>), or U+002F SOLIDUS (/).

    Thus no matter what, textarea needs a hefty entity translation handler or it will eventually Mojibake on entities!

  • CDATA (Character Data) will not treat tags inside the text as markup and will not expand entities.
    So as long as the raw snippet code does not violate rule 1 (that one can't have the containers closing character(sequence) inside the snippet), this requires no other escaping/encoding.

Clearly this boils down to: how can we minimize the number of characters/character-sequences that still need to be encoded in the snippet's raw source and the number of times that character(sequence) might appear in an average snippet; something that is also of importance for the javascript that handles the translation of these characters (if they occur).

So what 'containers' have this CDATA context?

Most value properties of tags are CDATA, so one could (ab)use a hidden input's value property (proof of concept jsfiddle here).
However (conform rule 1) this creates an encoding/escape problem with nested quotes (" and ') in the raw snippet and one needs some javascript to get/translate and set the snippet in another (visible) element (or simply setting it as a text-area's value). Somehow this gave me problems with entities in FF (just like in a textarea). But it doesn't really matter, since the 'price' of having to escape/encode nested quotes is higher then a (HTML5) textarea (quotes are quite common in source code..).

What about trying to (ab)use <![CDATA[<tag>bla & bla</tag>]]>?
As Jukka points out in his extended answer, this would only work in (rare) 'real xhtml'.
I thought of using a script-tag (with or without such a CDATA wrapper inside the script-tag) together with a multi-line comment /* */ that wraps the raw snippet (script-tags can have an id and you can access them by count). But since this obviously introduces a escaping problem with */, ]]> and </script in the raw snippet, this doesn't seem like a solution either.

Please post other viable 'containers' in the comments to this answer.

By the way, encoding or counting the number of - characters and balancing them out inside a comment tag <!-- --> is just insane for this purpose (apart from rule 1).

That leaves us with Jukka K. Korpela's excellent answer: the <xmp> tag seems the best option!

The 'forgotten' <xmp> holds CDATA, is intended for this purpose AND is indeed still in the current HTML 5 spec (and has been at least since HTML3.2); exactly what we need! It's also widely supported, even in IE6 (that is.. until it suffers from the same regression as the scrolling table-body).
Note: as Jukka pointed out, this will not work in true xhtml or polyglot (that will treat it as a pre) and the xmp tag must still adhere to rule no 1. But that's the 'only' rule.

Consider the following markup:

<!-- ATTENTION: replace any occurrence of &lt;/xmp with </xmp -->
<xmp id="snippet-container">
    <div>this is an example div &amp; holds an xmp tag:<br />
<html><head>  <!-- indentation col 0!! -->
    <title>My Title</title>
    <p>hello world !!</p>
        &lt;/xmp>  <!-- note this encoded/escaped tag -->
    This line is also part of the snippet

The above codeblok illustrates a raw piece of markup where <xmp id="snippet-container"> contains an (almost raw) code-snippet (containing div>div>xmp>html-document).
Notice the encoded closing tag in this markup? To comply with rule no 1, this was encoded/escaped).

So embedding/transporting the (sometimes almost) raw code is/seems solved.

What about displaying/rendering the snippet (and that encoded &lt;/xmp>)?

The browser will (or it should) render the snippet (the contents inside snippet-container) exactly the way you see it in the codeblock above (with some discrepancy amongst browsers whether or not the snippet starts with a blank line).
That includes the formatting/indentation, entities (like the string &amp;), full tags, comments AND the encoded closing tag &lt;/xmp> (just like it was encoded in the markup). And depending on browser(version) one could even try use the property contenteditable="true" to edit this snippet (all that without javascript enabled). Doing something like textarea.value=xmp.innerHTML is also a breeze.

So you can... if the snippet doesn't contain the containers closing character-sequence.

However, should a raw snippet contain the closing character-sequence </xmp (because it is an example of xmp itself or it contains some regex, etc), you must accept that you have to encode/escape that sequence in the raw snippet AND need a javascript handler to translate that encoding to display/render the encoded &lt;/xmp> like </xmp> inside a textarea (for editing/posting) or (for example) a pre just to correctly render the snippet's code (or so it seems).

A very rudimentary jsfiddle example of this here. Note that getting/embedding/displaying/retrieving-to-textarea worked perfect even in IE6. But setting the xmp's innerHTML revealed some interesting 'would-be-intelligent' behavior on IE's part. There is a more extensive note and workaround on that in the fiddle.

But now comes the important kicker (another reason why you only get very close): Just as an over-simplified example, imagine this rabbit-hole:

Intended raw code-snippet:

<!-- remember to translate between </xmp> and &lt;/xmp> -->
<p>a paragraph</p>

Well, to comply with rule 1, we 'only' need to encode those </xmp[> \n\r\t\f\/] sequences, right?

So that gives us the following markup (using just a possible encoding):

<xmp id="container">
<!-- remember to translate between &lt;/xmp> and &lt;/xmp> -->
<p>a paragraph</p>

Hmm.. shalt I get my crystal ball or flip a coin? No, let the computer look at its system-clock and state that a derived number is 'random'. Yes, that should do it..

Using a regex like: xmp.innerHTML.replace(/&lt;(?=\/xmp[> \n\r\t\f\/])/gi, '<');, would translate 'back' to this:

<!-- remember to translate between </xmp> and </xmp> -->
<p>a paragraph</p>

Hmm.. seems this random generator is broken... Houston..?
Should you have missed the joke/problem, read again starting at the 'intended raw code-snippet'.

Wait, I know, we (also) need to encode .... to ....
Ok, rewind to 'intended raw code-snippet' and read again.
Somehow this all begins to smell like the famous hilarious-but-true rexgex-answer on SO, a good read for people fluent in mojibake.

Maybe someone knows a clever algorithm or solution to fix this problem, but I assume that the embedded raw code will get more and more obscure to the point where you'd be better of properly escaping/encoding just your <, & (and >), just like the rest of the world.

Conclusion: (using the xmp tag)

  • it can be done with known snippets that do not contain the container's closing character-sequence,
  • we can get very close to the original objective with known snippets that only use 'basic first-level' escaping/encoding so we don't fall in the rabbithole,
  • but ultimately it seems that one can't do this reliably in a 'production-environment' where people can/should copy/paste/edit 'any unknown' raw snippets while not knowing/understanding the implications/rules/rabbithole (depending on your implementation of handling/translating for rule 1 and the rabbit-hole).

Hope this helps!

PS: Whilst I would appreciate an upvote if you find this explanation useful, I kind of think Jukka's answer should be the accepted answer (should no better option/answer come along), since he was the one who remembered the xmp tag (that I forgot about over the years and got 'distracted' by the commonly advocated PCDATA elements like pre, textarea, etc.).
This answer originated in explaining why you can't do it (with any unknown raw snippet) and explain some obvious pitfalls that some other (now deleted) answers overlooked when advising a textarea for embedding/transport. I've expanded my existing explanation to also support and further explain Jukka's answer (since all that entity and *CDATA stuff is almost harder than code-pages).

Custom Drawable for ProgressBar/ProgressDialog

I was having some trouble using an Indeterminate Progress Dialog with the solution here, after some work and trial and error I got it to work.

First, create the animation you want to use for the Progress Dialog. In my case I used 5 images.


<animation-list xmlns:android="">
    <item android:drawable="@drawable/icon_progress_dialog_drawable_1" android:duration="150" />
    <item android:drawable="@drawable/icon_progress_dialog_drawable_2" android:duration="150" />
    <item android:drawable="@drawable/icon_progress_dialog_drawable_3" android:duration="150" />
    <item android:drawable="@drawable/icon_progress_dialog_drawable_4" android:duration="150" />
    <item android:drawable="@drawable/icon_progress_dialog_drawable_5" android:duration="150" />

Where you want to show a ProgressDialog:

dialog = new ProgressDialog(Context.this);
dialog.setMessage("Some Text");;

This solution is really simple and worked for me, you could extend ProgressDialog and make it override the drawable internally, however, this was really too complicated for what I needed so I did not do it.

Unable to run 'adb root' on a rooted Android phone

I finally found out how to do this! Basically you need to run adb shell first and then while you're in the shell run su, which will switch the shell to run as root!

$: adb shell
$: su

The one problem I still have is that sqlite3 is not installed so the command is not recognized.

How do I change Android Studio editor's background color?

You can change it by going File => Settings (Shortcut CTRL+ ALT+ S) , from Left panel Choose Appearance , Now from Right Panel choose theme.

enter image description here

Android Studio 2.1

Preference -> Search for Appearance -> UI options , Click on DropDown Theme

enter image description here

Android 2.2

Android studio -> File -> Settings -> Appearance & Behavior -> Look for UI Options


Import External Themes

You can download custom theme from this website. Choose your theme, download it. To set theme Go to Android studio -> File -> Import Settings -> Choose the .jar file downloaded.

How to print pandas DataFrame without index

Similar to many of the answers above that use df.to_string(index=False), I often find it necessary to extract a single column of values in which case you can specify an individual column with .to_string using the following:

data = pd.DataFrame({'col1': np.random.randint(0, 100, 10), 
    'col2': np.random.randint(50, 100, 10), 
    'col3': np.random.randint(10, 10000, 10)})

print(data.to_string(columns=['col1'], index=False)

print(data.to_string(columns=['col1', 'col2'], index=False))

Which provides an easy to copy (and index free) output for use pasting elsewhere (Excel). Sample output:

col1  col2    
49    62    
97    97    
87    94    
85    61    
18    55

How to secure phpMyAdmin

The biggest threat is that an attacker could leverage a vulnerability such as; directory traversal, or using SQL Injection to call load_file() to read the plain text username/password in the configuration file and then Login using phpmyadmin or over tcp port 3306. As a pentester I have used this attack pattern to compromise a system.

Here is a great way to lock down phpmyadmin:

  • DO NOT ALLOW REMOTE ROOT LOGINS! Instead phpmyadmin can be configured to use "Cookie Auth" to limit what user can access the system. If you need some root privileges, create a custom account that can add/drop/create but doesn't have grant or file_priv.
  • Remove file_priv permissions from every account. file_priv is one of the most dangerous privileges in MySQL because it allows an attacker to read files or upload a backdoor.
  • Whitelist IP address who have access to the phpmyadmin interface. Here is an example .htaccess reulset:
Order deny,allow
Deny from all
allow from
  • Do not have a predictable file location like: Vulnerability scanners like Nessus/Nikto/Acunetix/w3af will scan for this.

  • Firewall off tcp port 3306 so that it cannot be accessed by an attacker.

  • Use HTTPS, otherwise data and passwords can be leaked to an attacker. If you don't want to fork out the $30 for a cert, then use a self-signed. You'll accept it once, and even if it was changed due to a MITM you'll be notified.

Global Variable from a different file Python

When you write

from file2 import *

it actually copies the names defined in file2 into the namespace of file1. So if you reassign those names in file1, by writing

foo = "bar"

for example, it will only make that change in file1, not file2. Note that if you were to change an attribute of foo, say by doing

foo.blah = "bar"

then that change would be reflected in file2, because you are modifying the existing object referred to by the name foo, not replacing it with a new object.

You can get the effect you want by doing this in

import file2 = "bar"
test = SomeClass()

(note that you should delete from foo import *) although I would suggest thinking carefully about whether you really need to do this. It's not very common that changing one module's variables from within another module is really justified.

Foreign key constraints: When to use ON UPDATE and ON DELETE

You'll need to consider this in context of the application. In general, you should design an application, not a database (the database simply being part of the application).

Consider how your application should respond to various cases.

The default action is to restrict (i.e. not permit) the operation, which is normally what you want as it prevents stupid programming errors. However, on DELETE CASCADE can also be useful. It really depends on your application and how you intend to delete particular objects.

Personally, I'd use InnoDB because it doesn't trash your data (c.f. MyISAM, which does), rather than because it has FK constraints.

What can MATLAB do that R cannot do?

In my experience moving from MATLAB to Python is an easier transition - Python with numpy/scipy is closer to MATLAB in terms of style and features than R. There are also open source direct MATLAB clones Octave and Scilab.

There is certainly much that MATLAB can do that R can't - in my area MATLAB is used a lot for real time data aquisition - most hardware companies include MATLAB interfaces. While this may be possible with R I imagine it would be a lot more involved. Also Simulink provides a whole area of functionality which I think is missing from R. I'm sure there is more but I'm not so familiar with R.

Run batch file from Java code

try following

try {
            String[] command = {"cmd.exe", "/C", "Start", "D:\\test.bat"};
            Process p =  Runtime.getRuntime().exec(command);           
        } catch (IOException ex) {

SQL Server 2008 - Case / If statements in SELECT Clause

The most obvious solutions are already listed. Depending on where the query is sat (i.e. in application code) you can't always use IF statements and the inline CASE statements can get painful where lots of columns become conditional. Assuming Col1 + Col3 + Col7 are the same type, and likewise Col2, Col4 + Col8 you can do this:

SELECT Col1, Col2 FROM tbl WHERE @Var LIKE 'xyz'
SELECT Col3, Col4 FROM tbl WHERE @Var LIKE 'zyx'
SELECT Col7, Col8 FROM tbl WHERE @Var NOT LIKE 'xyz' AND @Var NOT LIKE 'zyx'

As this is a single command there are several performance benefits with regard to plan caching. Also the Query Optimiser will quickly eliminate those statements where @Var doesn't match the appropriate value without touching the storage engine.

127 Return code from $?

Value 127 is returned by /bin/sh when the given command is not found within your PATH system variable and it is not a built-in shell command. In other words, the system doesn't understand your command, because it doesn't know where to find the binary you're trying to call.

What is "Linting"?

Linting is the process of running a program that will analyse code for potential errors.

See lint on wikipedia:

lint was the name originally given to a particular program that flagged some suspicious and non-portable constructs (likely to be bugs) in C language source code. The term is now applied generically to tools that flag suspicious usage in software written in any computer language.

How to base64 encode image in linux bash / shell

You need to use cat to get the contents of the file named 'DSC_0251.JPG', rather than the filename itself.

test="$(cat DSC_0251.JPG | base64)"

However, base64 can read from the file itself:

test=$( base64 DSC_0251.JPG )

Nginx location "not equal to" regex

According to nginx documentation

there is no syntax for NOT matching a regular expression. Instead, match the target regular expression and assign an empty block, then use location / to match anything else

So you could define something like

location ~ (dir1|file2\.php) { 
    # empty

location / {
    rewrite ^/(.*)$1 permanent; 

How do I work with dynamic multi-dimensional arrays in C?

int rows, columns;
/* initialize rows and columns to the desired value */

    arr = (int**)malloc(rows*sizeof(int*));
            arr[i] = (int*)malloc(cols*sizeof(int));

Using continue in a switch statement

It's syntactically correct and stylistically okay.

Good style requires every case: statement should end with one of the following:

 return (x);
 exit (x);
 throw (x);

Additionally, following case (x): immediately with

 case (y):

is permissible - bundling several cases that have exactly the same effect.

Anything else is suspected to be a mistake, just like if(a=4){...} Of course you need enclosing loop (while, for, do...while) for continue to work. It won't loop back to case() alone. But a construct like:

while(record = getNewRecord())
        case RECORD_TYPE_...;
        default: //unknown type
            continue; //skip processing this record altogether.
    //...more processing...
} okay.

How to create a new text file using Python

# Method 1
f = open("Path/To/Your/File.txt", "w")   # 'r' for reading and 'w' for writing
f.write("Hello World from " +    # Write inside file 
f.close()                                # Close file 

# Method 2
with open("Path/To/Your/File.txt", "w") as f:   # Opens file and casts as f 
    f.write("Hello World form " +       # Writing
    # File closed automatically

There are many more methods but these two are most common. Hope this helped!

Dynamic SQL results into temp table in SQL Stored procedure

CREATE PROCEDURE dbo.pdpd_DynamicCall 
    --- Create global temp table
    CREATE TABLE ##T1 ( column_1 varchar(10) , column_2 varchar(100) )

    SELECT @SQLString_2 = 'INSERT INTO ##T1( column_1, column_2) SELECT column_1 = "123", column_2 = "MUHAMMAD IMRON"'
    SELECT @SQLString_2 = REPLACE(@SQLString_2, '"', '''')


    --- Test Display records
    SELECT * FROM ##T1

    --- Drop global temp table 
    IF OBJECT_ID('tempdb..##T1','u') IS NOT NULL

Passing route control with optional parameter after root in express?

Express version:

"dependencies": {
    "body-parser": "^1.19.0",
    "express": "^4.17.1"

Optional parameter are very much handy, you can declare and use them easily using express:

app.get('/api/v1/tours/:cId/:pId/:batchNo?', (req, res)=>{
    console.log("category Id: "+req.params.cId);
    console.log("product ID: "+req.params.pId);
    if (req.params.batchNo){
        console.log("Batch No: "+req.params.batchNo);

In the above code batchNo is optional. Express will count it optional because after in URL construction, I gave a '?' symbol after batchNo '/:batchNo?'

Now I can call with only categoryId and productId or with all three-parameter.

enter image description here enter image description here

Reading the selected value from asp:RadioButtonList using jQuery

This worked for me...

<asp:RadioButtonList runat="server" ID="Intent">
  <asp:ListItem Value="Confirm">Yes!</asp:ListItem>
  <asp:ListItem Value="Postpone">Not now</asp:ListItem>
  <asp:ListItem Value="Decline">Never!</asp:ListItem>

The handler:

$(document).ready(function () {
   var rbvalue = $("input[name='<%=Intent.UniqueID%>']:radio:checked").val();

   if(rbvalue == "Confirm"){
    alert("Woohoo, Thanks!");
   } else if (rbvalue == "Postpone"){
    alert("Well, I really hope it's soon");
   } else if (rbvalue == "Decline"){
   } else {
    alert("How'd you get here? Who sent you?");

The important part: $("input[name='<%=Intent.UniqueID%>']:radio:checked").val();

How to manually deploy artifacts in Nexus Repository Manager OSS 3

You can upload artifacts via their native publishing capabilities (e.g. maven deploy, npm publish).

You can also upload artifacts to "raw" repositories via a simple curl request, e.g.

curl --fail -u admin:admin123 --upload-file foo.jar ''

Hibernate Error executing DDL via JDBC Statement

spring.jpa.hibernate.ddl-auto = update

change update to create, and run it

after run safely again change create to update so again all tables will not create and you can use your previous data

cat, grep and cut - translated to python

you need to use os.system module to execute shell command

import os

if you want to save the output for later use, you need to use subprocess module

import subprocess
child = subprocess.Popen('command',stdout=subprocess.PIPE,shell=True)
output = child.communicate()[0]

Reading file from Workspace in Jenkins with Groovy script

If you already have the Groovy (Postbuild) plugin installed, I think it's a valid desire to get this done with (generic) Groovy instead of installing a (specialized) plugin.

That said, you can get the workspace using Don't forget to add File.separator between path and file name.

Fast way to discover the row count of a table in PostgreSQL

Counting rows in big tables is known to be slow in PostgreSQL. To get a precise number it has to do a full count of rows due to the nature of MVCC. There is a way to speed this up dramatically if the count does not have to be exact like it seems to be in your case.

Instead of getting the exact count (slow with big tables):

SELECT count(*) AS exact_count FROM myschema.mytable;

You get a close estimate like this (extremely fast):

SELECT reltuples::bigint AS estimate FROM pg_class where relname='mytable';

How close the estimate is depends on whether you run ANALYZE enough. It is usually very close.
See the PostgreSQL Wiki FAQ.
Or the dedicated wiki page for count(*) performance.

Better yet

The article in the PostgreSQL Wiki is was a bit sloppy. It ignored the possibility that there can be multiple tables of the same name in one database - in different schemas. To account for that:

SELECT c.reltuples::bigint AS estimate
FROM   pg_class c
JOIN   pg_namespace n ON n.oid = c.relnamespace
WHERE  c.relname = 'mytable'
AND    n.nspname = 'myschema'

Or better still

SELECT reltuples::bigint AS estimate
FROM   pg_class
WHERE  oid = 'myschema.mytable'::regclass;

Faster, simpler, safer, more elegant. See the manual on Object Identifier Types.

Use to_regclass('myschema.mytable') in Postgres 9.4+ to avoid exceptions for invalid table names:

TABLESAMPLE SYSTEM (n) in Postgres 9.5+

SELECT 100 * count(*) AS estimate FROM mytable TABLESAMPLE SYSTEM (1);

Like @a_horse commented, the newly added clause for the SELECT command might be useful if statistics in pg_class are not current enough for some reason. For example:

  • No autovacuum running.
  • Immediately after a big INSERT or DELETE.
  • TEMPORARY tables (which are not covered by autovacuum).

This only looks at a random n % (1 in the example) selection of blocks and counts rows in it. A bigger sample increases the cost and reduces the error, your pick. Accuracy depends on more factors:

  • Distribution of row size. If a given block happens to hold wider than usual rows, the count is lower than usual etc.
  • Dead tuples or a FILLFACTOR occupy space per block. If unevenly distributed across the table, the estimate may be off.
  • General rounding errors.

In most cases the estimate from pg_class will be faster and more accurate.

Answer to actual question

First, I need to know the number of rows in that table, if the total count is greater than some predefined constant,

And whether it ...

... is possible at the moment the count pass my constant value, it will stop the counting (and not wait to finish the counting to inform the row count is greater).

Yes. You can use a subquery with LIMIT:

SELECT count(*) FROM (SELECT 1 FROM token LIMIT 500000) t;

Postgres actually stops counting beyond the given limit, you get an exact and current count for up to n rows (500000 in the example), and n otherwise. Not nearly as fast as the estimate in pg_class, though.

How to read file from relative path in Java project? cannot find the path specified

If it's already in the classpath, then just obtain it from the classpath instead of from the disk file system. Don't fiddle with relative paths in They are dependent on the current working directory over which you have totally no control from inside the Java code.

Assuming that ListStopWords.txt is in the same package as your FileLoader class, then do:

URL url = getClass().getResource("ListStopWords.txt");
File file = new File(url.getPath());

Or if all you're ultimately after is actually an InputStream of it:

InputStream input = getClass().getResourceAsStream("ListStopWords.txt");

This is certainly preferred over creating a new File() because the url may not necessarily represent a disk file system path, but it could also represent virtual file system path (which may happen when the JAR is expanded into memory instead of into a temp folder on disk file system) or even a network path which are both not per definition digestable by File constructor.

If the file is -as the package name hints- is actually a fullworthy properties file (containing key=value lines) with just the "wrong" extension, then you could feed the InputStream immediately to the load() method.

Properties properties = new Properties();

Note: when you're trying to access it from inside static context, then use FileLoader.class (or whatever YourClass.class) instead of getClass() in above examples.

How do I negate a condition in PowerShell?

If you are like me and dislike the double parenthesis, you can use a function

function not ($cm, $pm) {
  if (& $cm $pm) {0} else {1}

if (not Test-Path C:\Code) {'it does not exist!'}


How to create a generic array?

You should not mix-up arrays and generics. They don't go well together. There are differences in how arrays and generic types enforce the type check. We say that arrays are reified, but generics are not. As a result of this, you see these differences working with arrays and generics.

Arrays are covariant, Generics are not:

What that means? You must be knowing by now that the following assignment is valid:

Object[] arr = new String[10];

Basically, an Object[] is a super type of String[], because Object is a super type of String. This is not true with generics. So, the following declaration is not valid, and won't compile:

List<Object> list = new ArrayList<String>(); // Will not compile.

Reason being, generics are invariant.

Enforcing Type Check:

Generics were introduced in Java to enforce stronger type check at compile time. As such, generic types don't have any type information at runtime due to type erasure. So, a List<String> has a static type of List<String> but a dynamic type of List.

However, arrays carry with them the runtime type information of the component type. At runtime, arrays use Array Store check to check whether you are inserting elements compatible with actual array type. So, the following code:

Object[] arr = new String[10];
arr[0] = new Integer(10);

will compile fine, but will fail at runtime, as a result of ArrayStoreCheck. With generics, this is not possible, as the compiler will try to prevent the runtime exception by providing compile time check, by avoiding creation of reference like this, as shown above.

So, what's the issue with Generic Array Creation?

Creation of array whose component type is either a type parameter, a concrete parameterized type or a bounded wildcard parameterized type, is type-unsafe.

Consider the code as below:

public <T> T[] getArray(int size) {
    T[] arr = new T[size];  // Suppose this was allowed for the time being.
    return arr;

Since the type of T is not known at runtime, the array created is actually an Object[]. So the above method at runtime will look like:

public Object[] getArray(int size) {
    Object[] arr = new Object[size];
    return arr;

Now, suppose you call this method as:

Integer[] arr = getArray(10);

Here's the problem. You have just assigned an Object[] to a reference of Integer[]. The above code will compile fine, but will fail at runtime.

That is why generic array creation is forbidden.

Why typecasting new Object[10] to E[] works?

Now your last doubt, why the below code works:

E[] elements = (E[]) new Object[10];

The above code have the same implications as explained above. If you notice, the compiler would be giving you an Unchecked Cast Warning there, as you are typecasting to an array of unknown component type. That means, the cast may fail at runtime. For e.g, if you have that code in the above method:

public <T> T[] getArray(int size) {
    T[] arr = (T[])new Object[size];        
    return arr;

and you call invoke it like this:

String[] arr = getArray(10);

this will fail at runtime with a ClassCastException. So, no this way will not work always.

What about creating an array of type List<String>[]?

The issue is the same. Due to type erasure, a List<String>[] is nothing but a List[]. So, had the creation of such arrays allowed, let's see what could happen:

List<String>[] strlistarr = new List<String>[10];  // Won't compile. but just consider it
Object[] objarr = strlistarr;    // this will be fine
objarr[0] = new ArrayList<Integer>(); // This should fail but succeeds.

Now the ArrayStoreCheck in the above case will succeed at runtime although that should have thrown an ArrayStoreException. That's because both List<String>[] and List<Integer>[] are compiled to List[] at runtime.

So can we create array of unbounded wildcard parameterized types?

Yes. The reason being, a List<?> is a reifiable type. And that makes sense, as there is no type associated at all. So there is nothing to loose as a result of type erasure. So, it is perfectly type-safe to create an array of such type.

List<?>[] listArr = new List<?>[10];
listArr[0] = new ArrayList<String>();  // Fine.
listArr[1] = new ArrayList<Integer>(); // Fine

Both the above case is fine, because List<?> is super type of all the instantiation of the generic type List<E>. So, it won't issue an ArrayStoreException at runtime. The case is same with raw types array. As raw types are also reifiable types, you can create an array List[].

So, it goes like, you can only create an array of reifiable types, but not non-reifiable types. Note that, in all the above cases, declaration of array is fine, it's the creation of array with new operator, which gives issues. But, there is no point in declaring an array of those reference types, as they can't point to anything but null (Ignoring the unbounded types).

Is there any workaround for E[]?

Yes, you can create the array using Array#newInstance() method:

public <E> E[] getArray(Class<E> clazz, int size) {
    E[] arr = (E[]) Array.newInstance(clazz, size);

    return arr;

Typecast is needed because that method returns an Object. But you can be sure that it's a safe cast. So, you can even use @SuppressWarnings on that variable.

How do I get video durations with YouTube API version 3?

Youtube data 3 API , duration string to seconds conversion in Python




def convert_YouTube_duration_to_seconds(duration):
   day_time = duration.split('T')
   day_duration = day_time[0].replace('P', '')
   day_list = day_duration.split('D')
   if len(day_list) == 2:
      day = int(day_list[0]) * 60 * 60 * 24
      day_list = day_list[1]
      day = 0
      day_list = day_list[0]
   hour_list = day_time[1].split('H')
   if len(hour_list) == 2:
      hour = int(hour_list[0]) * 60 * 60
      hour_list = hour_list[1]
      hour = 0
      hour_list = hour_list[0]
   minute_list = hour_list.split('M')
   if len(minute_list) == 2:
      minute = int(minute_list[0]) * 60
      minute_list = minute_list[1]
      minute = 0
      minute_list = minute_list[0]
   second_list = minute_list.split('S')
   if len(second_list) == 2:
      second = int(second_list[0])
      second = 0
   return day + hour + minute + second

Assigning variables with dynamic names in Java

You don't. The closest thing you can do is working with Maps to simulate it, or defining your own Objects to deal with.

Change HTML email body font type and size in VBA

I did a little research and was able to write this code:

strbody = "<BODY style=font-size:11pt;font-family:Calibri>Good Morning;<p>We have completed our main aliasing process for today.  All assigned firms are complete.  Please feel free to respond with any questions.<p>Thank you.</BODY>"

apparently by setting the "font-size=11pt" instead of setting the font size <font size=5>, It allows you to select a specific font size like you normally would in a text editor, as opposed to selecting a value from 1-7 like my code was originally.

This link from simpLE MAn gave me some good info.

Skipping error in for-loop

One (dirty) way to do it is to use tryCatch with an empty function for error handling. For example, the following code raises an error and breaks the loop :

for (i in 1:10) {
    if (i==7) stop("Urgh, the iphone is in the blender !")

[1] 1
[1] 2
[1] 3
[1] 4
[1] 5
[1] 6
[1] 7
Erreur : Urgh, the iphone is in the blender !

But you can wrap your instructions into a tryCatch with an error handling function that does nothing, for example :

for (i in 1:10) {
    if (i==7) stop("Urgh, the iphone is in the blender !")
  }, error=function(e){})

[1] 1
[1] 2
[1] 3
[1] 4
[1] 5
[1] 6
[1] 7
[1] 8
[1] 9
[1] 10

But I think you should at least print the error message to know if something bad happened while letting your code continue to run :

for (i in 1:10) {
    if (i==7) stop("Urgh, the iphone is in the blender !")
  }, error=function(e){cat("ERROR :",conditionMessage(e), "\n")})

[1] 1
[1] 2
[1] 3
[1] 4
[1] 5
[1] 6
[1] 7
ERROR : Urgh, the iphone is in the blender ! 
[1] 8
[1] 9
[1] 10

EDIT : So to apply tryCatch in your case would be something like :

for (v in 2:180){
        mypath=file.path("C:", "file1", (paste("graph",names(mydata[columnname]), ".pdf", sep="-")))
        mytitle = paste("anything")
        myplotfunction(mydata[,columnnumber]) ## this function is defined previously in the program
    }, error=function(e){cat("ERROR :",conditionMessage(e), "\n")})

How to detect simple geometric shapes using OpenCV

You can also use template matching to detect shapes inside an image.

SQL Server: Error converting data type nvarchar to numeric

In case of float values with characters 'e' '+' it errors out if we try to convert in decimal. ('2.81104e+006'). It still pass ISNUMERIC test.

SELECT ISNUMERIC('2.81104e+006') 

returns 1.

SELECT convert(decimal(15,2), '2.81104e+006') 


error: Error converting data type varchar to numeric.


SELECT try_convert(decimal(15,2), '2.81104e+006') 

returns NULL.

SELECT convert(float, '2.81104e+006') 

returns the correct value 2811040.

How to list the size of each file and directory and sort by descending size in Bash?

[enhanced version]
This is going to be much faster and precise than the initial version below and will output the sum of all the file size of current directory:

echo `find . -type f -exec stat -c %s {} \; | tr '\n' '+' | sed 's/+$//g'` | bc

the stat -c %s command on a file will return its size in bytes. The tr command here is used to overcome xargs command limitations (apparently piping to xargs is splitting results on more lines, breaking the logic of my command). Hence tr is taking care of replacing line feed with + (plus) sign. sed has the only goal to remove the last + sign from the resulting string to avoid complains from the final bc (basic calculator) command that, as usual, does the math.

Performances: I tested it on several directories and over ~150.000 files top (the current number of files of my fedora 15 box) having what I believe it is an amazing result:

# time echo `find / -type f -exec stat -c %s {} \; | tr '\n' '+' | sed 's/+$//g'` | bc

real    2m19.164s
user    0m2.039s
sys 0m14.850s

Just in case you want to make a comparison with the du -sb / command, it will output an estimated disk usage in bytes (-b option)

# du -sb /
12684646920 /

As I was expecting it is a little larger than my command calculation because the du utility returns allocated space of each file and not the actual consumed space.

[initial version]
You cannot use du command if you need to know the exact sum size of your folder because (as per man page citation) du estimates file space usage. Hence it will lead you to a wrong result, an approximation (maybe close to the sum size but most likely greater than the actual size you are looking for).

I think there might be different ways to answer your question but this is mine:

ls -l $(find . -type f | xargs) | cut -d" " -f5 | xargs | sed 's/\ /+/g'| bc

It finds all files under . directory (change . with whatever directory you like), also hidden files are included and (using xargs) outputs their names in a single line, then produces a detailed list using ls -l. This (sometimes) huge output is piped towards cut command and only the fifth field (-f5), which is the file size in bytes is taken and again piped against xargs which produces again a single line of sizes separated by blanks. Now take place a sed magic which replaces each blank space with a plus (+) sign and finally bc (basic calculator) does the math.

It might need additional tuning and you may have ls command complaining about arguments list too long.

javascript code to check special characters

You can test a string using this regular expression:

function isValid(str){
 return !/[~`!#$%\^&*+=\-\[\]\\';,/{}|\\":<>\?]/g.test(str);

Read and parse a Json File in C#

Doing this yourself is an awful idea. Use Json.NET. It has already solved the problem better than most programmers could if they were given months on end to work on it. As for your specific needs, parsing into arrays and such, check the documentation, particularly on JsonTextReader. Basically, Json.NET handles JSON arrays natively and will parse them into strings, ints, or whatever the type happens to be without prompting from you. Here is a direct link to the basic code usages for both the reader and the writer, so you can have that open in a spare window while you're learning to work with this.

This is for the best: Be lazy this time and use a library so you solve this common problem forever.

VBA test if cell is in a range

From the Help:

Set isect = Application.Intersect(Range("rg1"), Range("rg2"))
If isect Is Nothing Then
    MsgBox "Ranges do not intersect"
End If

How to get the week day name from a date?

SQL> SELECT TO_CHAR(date '1982-03-09', 'DAY') day FROM dual;


SQL> SELECT TO_CHAR(date '1982-03-09', 'DY') day FROM dual;


SQL> SELECT TO_CHAR(date '1982-03-09', 'Dy') day FROM dual;


(Note that the queries use ANSI date literals, which follow the ISO-8601 date standard and avoid date format ambiguity.)

GIT clone repo across local file system in windows

While UNC path is supported since Git 2.21 (Feb. 2019, see below), Git 2.24 (Q4 2019) will allow

git clone file://

No more file:////xxx, 'file://' is enough to refer to an UNC path share.
See "Git Fetch Error with UNC".

Note, since 2016 and the MingW-64 git.exe packaged with Git for Windows, an UNC path is supported.
(See "How are msys, msys2, and MinGW-64 related to each other?")

And with Git 2.21 (Feb. 2019), this support extends even in in an msys2 shell (with quotes around the UNC path).

See commit 9e9da23, commit 5440df4 (17 Jan 2019) by Johannes Schindelin (dscho).
Helped-by: Kim Gybels (Jeff-G).
(Merged by Junio C Hamano -- gitster -- in commit f5dd919, 05 Feb 2019)

Before Git 2.21, due to a quirk in Git's method to spawn git-upload-pack, there is a problem when passing paths with backslashes in them: Git will force the command-line through the shell, which has different quoting semantics in Git for Windows (being an MSYS2 program) than regular Win32 executables such as git.exe itself.

The symptom is that the first of the two backslashes in UNC paths of the form \\myserver\folder\repository.git is stripped off.

This is mitigated now:

mingw: special-case arguments to sh

The MSYS2 runtime does its best to emulate the command-line wildcard expansion and de-quoting which would be performed by the calling Unix shell on Unix systems.

Those Unix shell quoting rules differ from the quoting rules applying to Windows' cmd and Powershell, making it a little awkward to quote command-line parameters properly when spawning other processes.

In particular, git.exe passes arguments to subprocesses that are not intended to be interpreted as wildcards, and if they contain backslashes, those are not to be interpreted as escape characters, e.g. when passing Windows paths.

Note: this is only a problem when calling MSYS2 executables, not when calling MINGW executables such as git.exe. However, we do call MSYS2 executables frequently, most notably when setting the use_shell flag in the child_process structure.

There is no elegant way to determine whether the .exe file to be executed is an MSYS2 program or a MINGW one.
But since the use case of passing a command line through the shell is so prevalent, we need to work around this issue at least when executing sh.exe.

Let's introduce an ugly, hard-coded test whether argv[0] is "sh", and whether it refers to the MSYS2 Bash, to determine whether we need to quote the arguments differently than usual.

That still does not fix the issue completely, but at least it is something.

Incidentally, this also fixes the problem where git clone \\server\repo failed due to incorrect handling of the backslashes when handing the path to the git-upload-pack process.

Further, we need to take care to quote not only whitespace and backslashes, but also curly brackets.
As aliases frequently go through the MSYS2 Bash, and as aliases frequently get parameters such as HEAD@{yesterday}, this is really important.

See t/

Why does Boolean.ToString output "True" and not "true"

How is it not compatible with C#? Boolean.Parse and Boolean.TryParse is case insensitive and the parsing is done by comparing the value to Boolean.TrueString or Boolean.FalseString which are "True" and "False".

EDIT: When looking at the Boolean.ToString method in reflector it turns out that the strings are hard coded so the ToString method is as follows:

public override string ToString()
    if (!this)
        return "False";
    return "True";

jQuery click events firing multiple times

In my case I had loaded the same *.js file on the page twice in a <script> tag, so both files were attaching event handlers to the element. I removed the duplicate declaration and that fixed the problem.

XMLHttpRequest cannot load an URL with jQuery

Fiddle with 3 working solutions in action.

Given an external JSON:

myurl = '|zh-hant|fr&props=sitelinks|labels|aliases|descriptions&format=json'

Solution 1: $.ajax() + jsonp:

  dataType: "jsonp",
  url: myurl ,
  }).done(function ( data ) {
  // do my stuff

Solution 2: $.ajax()+json+&calback=?:

  dataType: "json",
  url: myurl + '&callback=?',
  }).done(function ( data ) {
  // do my stuff

Solution 3: $.getJSON()+calback=?:

$.getJSON( myurl + '&callback=?', function(data) {
  // do my stuff

Documentations: ,

jQuery UI autocomplete with item and id

At last i did it Thanks alot friends, and a special thanks to Mr because of his code i was able to solve it properly. finally my code is looking like this as i am using groovy grails i hope this will help somebody there.. Thanks alot

html code looks like this in my gsp page

  <input id="populate-dropdown" name="nameofClient" type="text">
  <input id="wilhaveid" name="idofclient" type="text">

script Function is like this in my gsp page

        $( "#populate-dropdown").on('input', function() {
                data: {inputField: $("#populate-dropdown").val()},
                success: function(resp){
                        select: function (event, ui) {
                             return false;

And my controller code is like this

   def autoCOmp(){
    def c = Client.createCriteria()
    def results = c.list {
        like("nameOfClient", params.inputField+"%")

    def itemList = []
        itemList  << [,label:it.nameOfClient]
    render itemList as JSON

One more thing i have not set id field hidden because at first i was checking that i am getting the exact id , you can keep it hidden just put type=hidden instead of text for second input item in html

Thanks !

How do I clone a job in Jenkins?

All above answers are good. But if you have created "folders" for your jobs, things are slightly different.

Click on the folder under which you want to create a new job. Then click "New Item" on the left menu. Now your "new job" URL will look like this (assuming you are creating the new job under "my-folder"):


Under Enter an item name, enter your desired new job name. Then use the Copy from text box at the bottom. Enter job path of he source job.

E.g. If your source job is under folder src-folder and name of the job is src-job, you will have to enter src-folder/src-job in "Copy from" box.

Hope it helps.

Vertical rulers in Visual Studio Code

With Visual Studio Code 1.27.2:

  1. When I go to File > Preference > Settings, I get the following tab


  2. I type rulers in Search settings and I get the following list of settings


  3. Clicking on the first Edit in settings.json, I can edit the user settings


  4. Clicking on the pen icon that appears to the left of the setting in Default user settings I can copy it on the user settings and edit it

With Visual Studio Code 1.38.1, the screenshot shown on the third point changes to the following one.

enter image description here

The panel for selecting the default user setting values isn't shown anymore.

Node.js getaddrinfo ENOTFOUND

  var http=require('http');
   http.get('', function(res){
        var str = '';
        console.log('Response is '+res.statusCode);

        res.on('data', function (chunk) {
               str += chunk;

        res.on('end', function () {


How to force child div to be 100% of parent div's height without specifying parent's height?

My solution:

$(window).resize(function() {
        $(window).height() - $('#div_to_occupy_the_rest').offset().top

System.BadImageFormatException: Could not load file or assembly

I found a different solution to this issue. Apparently my IIS 7 did not have 32bit mode enabled in my Application Pool by default.

To enable 32bit mode, open IIS and select your Application Pool. Mine was named "ASP.NET v4.0".
Right click, go to "Advanced Settings" and change the section named: "Enabled 32-bit Applications" to true.

Restart your web server and try again.

I found the fix from this blog reference:

Additionally, you can change the settings on Visual Studio. In my case, I went to Tools > Options > Projects and Solutions > Web Projects and checked Use the 64 bit version of IIS Express for web sites and projects - This was on VS Pro 2015. Nothing else fixed it but this.

How to open URL in Microsoft Edge from the command line?

It will do more or less the same thing in good old dos script fashion

set add=%1
if %add%$ ==$ set add="about:blank" && goto launch

rem http://
set test=%add:~0, 7%
if %test% == http:// goto launch

rem ftp:// 
set test=%add:~0, 6%
if %test% == ftp:// goto launch

rem https://
set test=%add:~0, 8%
if %test% == https:// goto launch

rem add http
set add=http://%add%

start microsoft-edge:%add%

How to read/write a boolean when implementing the Parcelable interface?

It is hard to identify the real question here. I guess it is how to deal with booleans when implementing the Parcelable interface.

Some attributes of MyObject are boolean but Parcel don't have any method read/writeBoolean.

You will have to either store the value as a string or as a byte. If you go for a string then you'll have to use the static method of the String class called valueOf() to parse the boolean value. It isn't as effective as saving it in a byte tough.


If you go for a byte you'll have to implement a conversion logic yourself.

byte convBool = -1;
if (theBoolean) {
    convBool = 1;
} else {
    convBool = 0;

When unmarshalling the Parcel object you have to take care of the conversion to the original type.

How to use adb command to push a file on device without sd card

In Mac: To push files via adb

adb push /Users/Downloads?/amazon.sdktester.json '/mnt/sdcard/amazon.sdktester.json'

The following classes could not be instantiated: -

I had the same error on my Android Studio screen when i wanted to prevew my project. I fix the problem by this ways:

1- I chang the version from 22 to 21. But if I change back to version 22, the rendering breaks, if I switch back to 21, it works again. Thank you @Overloaded_Operator

I updated my Android Studio but not working. Thank you @Salvuccio96

How to detect scroll position of page using jQuery

GET Scroll Position:

var scrolled_val = window.scrollY;

DETECT Scroll Position:

     function (event) 
          var scrolled_val = window.scrollY;

Laravel Fluent Query Builder Join with subquery

Query with sub query in Laravel

$resortData = DB::table('resort')
        ->leftJoin('country', '', '=', '')
        ->leftJoin('states', 'resort.state', '=', '')
        ->leftJoin('city', '', '=', '')
        ->select('resort.*', ' as country_name', ' as state_name',' as city_name', DB::raw("(SELECT GROUP_CONCAT( from resort_amenities LEFT JOIN amenities on resort_amenities.amenities_id WHERE as amenities_name"))->groupBy('')
        ->orderBy('', 'DESC')

Can I serve multiple clients using just Flask as standalone?

Tips from 2020:

From Flask 1.0, it defaults to enable multiple threads (source), you don't need to do anything, just upgrade it with:

$ pip install -U flask

If you are using flask run instead of with older versions, you can control the threaded behavior with a command option (--with-threads/--without-threads):

$ flask run --with-threads

It's same as

How to check if current thread is not main thread

Allow me to preface this with: I acknowledged this post has the 'Android' tag, however, my search had nothing to do with 'Android' and this was my top result. To that end, for the non-Android SO Java users landing here, don't forget about:

public static void main(String[] args{
    /*...the rest of main...*/

After setting this, elsewhere in your code, you can easily check if you're about to execute on the main thread with:

    //do something on main thread

A bit embarrassed I had searched before remembering this, but hopefully it will help someone else!

How do I get the web page contents from a WebView?

Per issue 12987, Blundell's answer crashes (at least on my 2.3 VM). Instead, I intercept a call to console.log with a special prefix:

// intercept calls to console.log
web.setWebChromeClient(new WebChromeClient() {
    public boolean onConsoleMessage(ConsoleMessage cmsg)
        // check secret prefix
        if (cmsg.message().startsWith("MAGIC"))
            String msg = cmsg.message().substring(5); // strip off prefix

            /* process HTML */

            return true;

        return false;

// inject the JavaScript on page load
web.setWebViewClient(new WebViewClient() {
    public void onPageFinished(WebView view, String address)
        // have the page spill its guts, with a secret prefix


Path of assets in CSS files in Symfony 2

I have came across the very-very-same problem.

In short:

  • Willing to have original CSS in an "internal" dir (Resources/assets/css/a.css)
  • Willing to have the images in the "public" dir (Resources/public/images/devil.png)
  • Willing that twig takes that CSS, recompiles it into web/css/a.css and make it point the image in /web/bundles/mynicebundle/images/devil.png

I have made a test with ALL possible (sane) combinations of the following:

  • @notation, relative notation
  • Parse with cssrewrite, without it
  • CSS image background vs direct <img> tag src= to the very same image than CSS
  • CSS parsed with assetic and also without parsing with assetic direct output
  • And all this multiplied by trying a "public dir" (as Resources/public/css) with the CSS and a "private" directory (as Resources/assets/css).

This gave me a total of 14 combinations on the same twig, and this route was launched from

  • "/app_dev.php/"
  • "/app.php/"
  • and "/"

thus giving 14 x 3 = 42 tests.

Additionally, all this has been tested working in a subdirectory, so there is no way to fool by giving absolute URLs because they would simply not work.

The tests were two unnamed images and then divs named from 'a' to 'f' for the CSS built FROM the public folder and named 'g to 'l' for the ones built from the internal path.

I observed the following:

Only 3 of the 14 tests were shown adequately on the three URLs. And NONE was from the "internal" folder (Resources/assets). It was a pre-requisite to have the spare CSS PUBLIC and then build with assetic FROM there.

These are the results:

  1. Result launched with /app_dev.php/ Result launched with /app_dev.php/

  2. Result launched with /app.php/ Result launched with /app.php/

  3. Result launched with / enter image description here

So... ONLY - The second image - Div B - Div C are the allowed syntaxes.

Here there is the TWIG code:

            {% stylesheets 'bundles/commondirty/css_original/container.css' filter="cssrewrite" %}
                <link href="{{ asset_url }}" rel="stylesheet" type="text/css" />
            {% endstylesheets %}

    {# First Row: ABCDEF #}

            <link href="{{ '../bundles/commondirty/css_original/a.css' }}" rel="stylesheet" type="text/css" />
            <link href="{{ asset( 'bundles/commondirty/css_original/b.css' ) }}" rel="stylesheet" type="text/css" />

            {% stylesheets 'bundles/commondirty/css_original/c.css' filter="cssrewrite" %}
                <link href="{{ asset_url }}" rel="stylesheet" type="text/css" />
            {% endstylesheets %}

            {% stylesheets 'bundles/commondirty/css_original/d.css' %}
                <link href="{{ asset_url }}" rel="stylesheet" type="text/css" />
            {% endstylesheets %}

            {% stylesheets '@CommonDirtyBundle/Resources/public/css_original/e.css' filter="cssrewrite" %}
                <link href="{{ asset_url }}" rel="stylesheet" type="text/css" />
            {% endstylesheets %}

            {% stylesheets '@CommonDirtyBundle/Resources/public/css_original/f.css' %}
                <link href="{{ asset_url }}" rel="stylesheet" type="text/css" />
            {% endstylesheets %}

    {# First Row: GHIJKL #}

            <link href="{{ '../../src/Common/DirtyBundle/Resources/assets/css/g.css' }}" rel="stylesheet" type="text/css" />
            <link href="{{ asset( '../src/Common/DirtyBundle/Resources/assets/css/h.css' ) }}" rel="stylesheet" type="text/css" />

            {% stylesheets '../src/Common/DirtyBundle/Resources/assets/css/i.css' filter="cssrewrite" %}
                <link href="{{ asset_url }}" rel="stylesheet" type="text/css" />
            {% endstylesheets %}

            {% stylesheets '../src/Common/DirtyBundle/Resources/assets/css/j.css' %}
                <link href="{{ asset_url }}" rel="stylesheet" type="text/css" />
            {% endstylesheets %}

            {% stylesheets '@CommonDirtyBundle/Resources/assets/css/k.css' filter="cssrewrite" %}
                <link href="{{ asset_url }}" rel="stylesheet" type="text/css" />
            {% endstylesheets %}

            {% stylesheets '@CommonDirtyBundle/Resources/assets/css/l.css' %}
                <link href="{{ asset_url }}" rel="stylesheet" type="text/css" />
            {% endstylesheets %}

        <div class="container">
                <img alt="Devil" src="../bundles/commondirty/images/devil.png">
                <img alt="Devil" src="{{ asset('bundles/commondirty/images/devil.png') }}">
                <div class="a">
                <div class="b">
                <div class="c">
                <div class="d">
                <div class="e">
                <div class="f">
                <div class="g">
                <div class="h">
                <div class="i">
                <div class="j">
                <div class="k">
                <div class="l">

The container.css:

    border: 1px solid red;
    padding: 0px;

div.container img, div.container div 
    border: 1px solid green;
    padding: 5px;
    margin: 5px;
    width: 64px;
    height: 64px;
    display: inline-block;
    vertical-align: top;

And a.css, b.css, c.css, etc: all identical, just changing the color and the CSS selector.

    background: red url('../images/devil.png');

The "directories" structure is:

Directories Directories

All this came, because I did not want the individual original files exposed to the public, specially if I wanted to play with "less" filter or "sass" or similar... I did not want my "originals" published, only the compiled one.

But there are good news. If you don't want to have the "spare CSS" in the public directories... install them not with --symlink, but really making a copy. Once "assetic" has built the compound CSS, and you can DELETE the original CSS from the filesystem, and leave the images:

Compilation process Compilation process

Note I do this for the --env=prod environment.

Just a few final thoughts:

  • This desired behaviour can be achieved by having the images in "public" directory in Git or Mercurial and the "css" in the "assets" directory. That is, instead of having them in "public" as shown in the directories, imagine a, b, c... residing in the "assets" instead of "public", than have your installer/deployer (probably a Bash script) to put the CSS temporarily inside the "public" dir before assets:install is executed, then assets:install, then assetic:dump, and then automating the removal of CSS from the public directory after assetic:dump has been executed. This would achive EXACTLY the behaviour desired in the question.

  • Another (unknown if possible) solution would be to explore if "assets:install" can only take "public" as the source or could also take "assets" as a source to publish. That would help when installed with the --symlink option when developing.

  • Additionally, if we are going to script the removal from the "public" dir, then, the need of storing them in a separate directory ("assets") disappears. They can live inside "public" in our version-control system as there will be dropped upon deploy to the public. This allows also for the --symlink usage.

BUT ANYWAY, CAUTION NOW: As now the originals are not there anymore (rm -Rf), there are only two solutions, not three. The working div "B" does not work anymore as it was an asset() call assuming there was the original asset. Only "C" (the compiled one) will work.

So... there is ONLY a FINAL WINNER: Div "C" allows EXACTLY what it was asked in the topic: To be compiled, respect the path to the images and do not expose the original source to the public.

The winner is C

The winner is C

How can I Convert HTML to Text in C#?

I had some decoding issues with HtmlAgility and I didn't want to invest time investigating it.

Instead I used that utility from the Microsoft Team Foundation API:

var text = HtmlFilter.ConvertToPlainText(htmlContent);

How to add hyperlink in JLabel?

Update I've tidied up the SwingLink class further and added more features; an up-to-date copy of it can be found here:

@McDowell's answer is great, but there's several things that could be improved upon. Notably text other than the hyperlink is clickable and it still looks like a button even though some of the styling has been changed/hidden. While accessibility is important, a coherent UI is as well.

So I put together a class extending JLabel based on McDowell's code. It's self-contained, handles errors properly, and feels more like a link:

public class SwingLink extends JLabel {
  private static final long serialVersionUID = 8273875024682878518L;
  private String text;
  private URI uri;

  public SwingLink(String text, URI uri){

  public SwingLink(String text, String uri){

  public void setup(String t, URI u){
    text = t;
    uri = u;
    addMouseListener(new MouseAdapter() {
      public void mouseClicked(MouseEvent e) {
      public void mouseEntered(MouseEvent e) {
      public void mouseExited(MouseEvent e) {

  public void setText(String text){

  public void setText(String text, boolean ul){
    String link = ul ? "<u>"+text+"</u>" : text;
    super.setText("<html><span style=\"color: #000099;\">"+
    this.text = text;

  public String getRawText(){
    return text;

  private static void open(URI uri) {
    if (Desktop.isDesktopSupported()) {
      Desktop desktop = Desktop.getDesktop();
      try {
      } catch (IOException e) {
            "Failed to launch the link, your computer is likely misconfigured.",
            "Cannot Launch Link",JOptionPane.WARNING_MESSAGE);
    } else {
          "Java is not able to launch links on your computer.",
          "Cannot Launch Link", JOptionPane.WARNING_MESSAGE);

You could also, for instance, change the link color to purple after being clicked, if that seemed useful. It's all self contained, you simply call:

SwingLink link = new SwingLink("Java", "");

How to run test methods in specific order in JUnit4?

The (as yet unreleased) change introduces a @SortMethodsWith. at least made the order predictable without that (in Java 7 it can be quite random).

How do I pass options to the Selenium Chrome driver using Python?

Code which disable chrome extensions for ones, who uses DesiredCapabilities to set browser flags :

desired_capabilities['chromeOptions'] = {
    "args": ["--disable-extensions"],
    "extensions": []

Object variable or With block variable not set (Error 91)

As I wrote in my comment, the solution to your problem is to write the following:

Set hyperLinkText = hprlink.Range

Set is needed because TextRange is a class, so hyperLinkText is an object; as such, if you want to assign it, you need to make it point to the actual object that you need.

Undo scaffolding in Rails

To generate scaffolding :

rails generate scaffold xyz

To revert scaffolding :

rails destroy scaffold xyz

Base64: java.lang.IllegalArgumentException: Illegal character

Just use the below code to resolve this:

JsonObject obj = Json.createReader(new ByteArrayInputStream(Base64.getDecoder().decode(accessToken.split("\\.")[1].
                        replace('-', '+').replace('_', '/')))).readObject();

In the above code replace('-', '+').replace('_', '/') did the job. For more details see the I understood the problem from the part of the code got from that link:

function url_base64_decode(str) {
  var output = str.replace(/-/g, '+').replace(/_/g, '/');
  switch (output.length % 4) {
    case 0:
    case 2:
      output += '==';
    case 3:
      output += '=';
      throw 'Illegal base64url string!';
  var result = window.atob(output); //polifyll
    return decodeURIComponent(escape(result));
  } catch (err) {
    return result;

Regular expression to match standard 10 digit phone number

Phone number regex that I use: /^[+]?(\d{1,2})?[\s.-]?\(?\d{3}\)?[\s.-]?\d{3}[\s.-]?\d{4}$/


  • 18001234567
  • 1 800 123 4567
  • +1 800 123-4567
  • +86 800 123 4567
  • 1-800-123-4567
  • 1 (800) 123-4567
  • (800)123-4567
  • (800) 123-4567
  • (800)1234567
  • 800-123-4567
  • 800.123.4567

how to make a div to wrap two float divs inside?

It's a common problem when you have two floats inside a block. The best way of fixing it is using clear:both after the second div.

<div style="display: block; clear: both;"></div>

It should force the container to be the correct height.

use a javascript array to fill up a drop down select box

This is a part from a REST-Service I´ve written recently.

var select = $("#productSelect")
for (var prop in data) {
    var option = document.createElement('option');
    option.innerHTML = data[prop].ProduktName
    option.value = data[prop].ProduktName;

The reason why im posting this is because appendChild() wasn´t working in my case so I decided to put up another possibility that works aswell.

Remove trailing comma from comma-separated string

Check if str.charAt(str.length() -1) == ','. Then do str = str.substring(0, str.length()-1)

ADB not responding. You can wait more,or kill "adb.exe" process manually and click 'Restart'

I had this problem on Windows 7. My situation is this through SDK Manager. I only download API 19 but I had not downloaded related Android SDK build-tools. So it occur this problem.

I went through SDK Manager download build-tools 19 to fix it. Hope to give you help.

What's the best way to validate an XML file against an XSD file?

I had to validate an XML against XSD just one time, so I tried XMLFox. I found it to be very confusing and weird. The help instructions didn't seem to match the interface.

I ended up using LiquidXML Studio 2008 (v6) which was much easier to use and more immediately familiar (the UI is very similar to Visual Basic 2008 Express, which I use frequently). The drawback: the validation capability is not in the free version, so I had to use the 30 day trial.

How to hide only the Close (x) button?

If you really want to hide it, as in "not visible", then you will probably have to create a borderless form and draw the caption components yourself. VisualStyles library has the Windows Elements available. You would also have to add back in the functionality of re-sizing the form or moving the form by grabbing the caption bar. Not to mention the system menu in the corner.

In most cases, it's hard to justify having the "close" button not available, especially when you want a modal form with minimizing capabilities. Minimizing a modal form really makes no sense.

How to check whether a str(variable) is empty or not?

Some time we have more spaces in between quotes, then use this approach

a = "   "
>>> bool(a)
>>> bool(a.strip())

if not a.strip():
    print("String is empty")
    print("String is not empty")

Uint8Array to string in Javascript

TextEncoder and TextDecoder from the Encoding standard, which is polyfilled by the stringencoding library, converts between strings and ArrayBuffers:

var uint8array = new TextEncoder("utf-8").encode("¢");
var string = new TextDecoder("utf-8").decode(uint8array);

How do I sleep for a millisecond in Perl?

A quick googling on "perl high resolution timers" gave a reference to Time::HiRes. Maybe that it what you want.

What's the difference between ViewData and ViewBag?

All answers suggest that ViewBag and/or ViewData is to pass data from Controller to Views which is misinformation. both are very useful to pass data from Views to Layout or Partial to Views (or ViewComponents, etc) It's not controller exclusive.

as the default sample have this in the layout page:

<title>@ViewData["Title"] - MyApp</title>

and in any view

ViewData["Title"] = "Details";

So then, to asking the question: "what's the difference between ViewBag and ViewData?"

The most notable difference is ViewData is a Strongly Typed Dictionary while ViewBag is a dynamic type.

Note that the data inside IS THE SAME

ViewData["Title"] = "MyTitle";
ViewBag.Title; // returns "MyTitle";

When to use one or another?

  • ViewBag doesn't support not valid C# names. you can't access ViewData["Key With Space"] with ViewBag
  • ViewBag.Something is dynamic and you may have problems when calling methods (like extension methods) that needs to know the exact parameter at compile time.
  • ViewBag can check for nulls syntactical cleaner: ViewBag.Person?.Name
  • ViewData have all the properties of a Dictionary like ContainsKey, Add, etc. so you can use ViewData.Add("somekey", "somevalue") keep in mind it might throw exceptions.
  • Using ViewData on views needs TypeCasting while ViewBag don't.

Knowing the subtle differences, using one or another is much more a taste preference.

Normally you can think of ViewBag.AnyKey to an alias of ViewData["AnyKey"]

Current user in Magento?

Found under "app/code/core/Mage/Page/Block/Html/Header.php":

public function getWelcome()
    if (empty($this->_data['welcome'])) {
        if (Mage::app()->isInstalled() && Mage::getSingleton('customer/session')->isLoggedIn()) {
            $this->_data['welcome'] = $this->__('Welcome, %s!', Mage::getSingleton('customer/session')->getCustomer()->getName());
        } else {
            $this->_data['welcome'] = Mage::getStoreConfig('design/header/welcome');

    return $this->_data['welcome'];

So it looks like Mage::getSingleton('customer/session')->getCustomer() will get your current logged in customer ;)

To get the currently logged in admin:


Detecting input change in jQuery?

With HTML5 and without using jQuery, you can using the input event:

var input = document.querySelector('input');

input.addEventListener('input', function()
    console.log('input changed to: ', input.value);

This will fire each time the input's text changes.

Supported in IE9+ and other browsers.

Try it live in a jsFiddle here.

Programmatically relaunch/recreate an activity?

After looking for the gingerbread implement for recreate, I'd like to use following codes (for gingerbread):

activity.mMainThread.mAppThread.scheduleRelaunchActivity(activity.mToken, null, null, 0, false, null);

For these codes, it's from the implementation in higher api.

public void recreate() {
    if (mParent != null) {
        throw new IllegalStateException("Can only be called on top-level activity");
    if (Looper.myLooper() != mMainThread.getLooper()) {
        throw new IllegalStateException("Must be called from main thread");
    mMainThread.requestRelaunchActivity(mToken, null, null, 0, false, null, false);

Api-10 has no requestRelaunchActivity, however, from the diff, i found this:

             public final void scheduleRelaunchActivity(IBinder token,
                     List<ResultInfo> pendingResults, List<Intent> pendingNewIntents,
                     int configChanges, boolean notResumed, Configuration config) {
    -            ActivityClientRecord r = new ActivityClientRecord();
    -            r.token = token;
    -            r.pendingResults = pendingResults;
    -            r.pendingIntents = pendingNewIntents;
    -            r.startsNotResumed = notResumed;
    -            r.createdConfig = config;
    -            synchronized (mPackages) {
    -                mRelaunchingActivities.add(r);
    -            }
    -            queueOrSendMessage(H.RELAUNCH_ACTIVITY, r, configChanges);
    +            requestRelaunchActivity(token, pendingResults, pendingNewIntents,
    +                    configChanges, notResumed, config, true);

So I think I could use scheduleRelaunchActivity instead of requestRelaunchActivity.

And I have written them using reflect:

package me.piebridge.util;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.List;

import android.annotation.TargetApi;
import android.content.res.Configuration;
import android.os.Build;
import android.os.IBinder;

public class GingerBreadUtil {

    private static Field scanField(Class<?> clazz, String... names) {
        for (String name : names) {
            Field field;
            try {
                field = clazz.getDeclaredField(name);
                return field;
            } catch (NoSuchFieldException e) {
            try {
                field = clazz.getField(name);
                return field;
            } catch (NoSuchFieldException e) {
        return null;

    public static void recreate(Activity activity) {
        } else {
            try {
            } catch (InvocationTargetException e) {
            } catch (Exception e) {

    private static void recreateHC(Activity activity) {
        ((Activity) activity).recreate();

    private static void recreateGB(Activity activity) throws IllegalArgumentException, IllegalAccessException, NoSuchMethodException, InvocationTargetException {
        Field Activity$mToken = scanField(Activity.class, "mToken");
        IBinder mToken = (IBinder) Activity$mToken.get(activity);
        Field Activity$mMainThread = scanField(Activity.class, "mMainThread");
        Object mMainThread = Activity$mMainThread.get(activity);
        Field ActivityThread$mAppThread = scanField(mMainThread.getClass(), "mAppThread");
        Object mAppThread = ActivityThread$mAppThread.get(mMainThread);
        Method method = mAppThread.getClass().getMethod("scheduleRelaunchActivity",
            IBinder.class, List.class, List.class, int.class, boolean.class, Configuration.class);
        method.invoke(mAppThread, mToken, null, null, 0, false, null);


I'm using these codes for the back-porting of xposed framework.

TypeError: can only concatenate list (not "str") to list

Let me fix your code

inventory=["sword", "potion", "armour", "bow"]
print("\ncommands: use (remove) and pickup (add)")
selection=input("choose a command [use/pickup]")

if selection == "use":
    inventory.remove(input("What do you want to use? "))
elif selection == "pickup":
    add=input("What do you want to pickup? ")
    newinv=inventory+[str(add)] #use '[str(add)]' or list(str(add))

The error is you are adding string and list, you should use list or [] to make the string become list type

CSS Display an Image Resized and Cropped

object-fit may help you, if you're playing with <img> tag

The below code will crop your image for you. You can play around with object-fit

img {
  object-fit: cover;
  width: 300px;
  height: 337px;

Django ChoiceField

If your choices are not pre-decided or they are coming from some other source, you can generate them in your view and pass it to the form .


def my_view(request, interview_pk):
    interview = Interview.objects.get(pk=interview_pk)
    all_rounds = interview.round_set.order_by('created_at')
    all_round_names = [ for rnd in all_rounds]
    form = forms.AddRatingForRound(all_round_names)
    return render(request, 'add_rating.html', {'form': form, 'interview': interview, 'rounds': all_rounds})

class AddRatingForRound(forms.ModelForm):

    def __init__(self, round_list, *args, **kwargs):
        super(AddRatingForRound, self).__init__(*args, **kwargs)
        self.fields['name'] = forms.ChoiceField(choices=tuple([(name, name) for name in round_list]))

    class Meta:
        model = models.RatingSheet
        fields = ('name', )


<form method="post">
    {% csrf_token %}
    {% if interview %}
         {{ interview }}
    {% endif %}
    {% if rounds %}
        {{ form.as_p }}
        <input type="submit" value="Submit" />
    {% else %}
        <h3>No rounds found</h3>
    {% endif %}


How do I ignore all files in a folder with a Git repository in Sourcetree?

Ignore full folder on source tree.

   Just Open Repository >Repository setting > Edit git ignore File and 
   you can rite some thing like this :


For bin folder and obj folder just write : */bin/ */obj/

Jquery get input array field

var data = $("input[name='page_title[]']")
  .map(function () {
    return $(this).val();

Bootstrap 3 unable to display glyphicon properly

the icons and the css are now seperated out from bootstrap. here is a fiddle that is from another stackoverflow answer

@import url("//");

Bootstrap 3 Glyphicons CDN

Why is list initialization (using curly braces) better than the alternatives?

Basically copying and pasting from Bjarne Stroustrup's "The C++ Programming Language 4th Edition":

List initialization does not allow narrowing (§iso.8.5.4). That is:

  • An integer cannot be converted to another integer that cannot hold its value. For example, char to int is allowed, but not int to char.
  • A floating-point value cannot be converted to another floating-point type that cannot hold its value. For example, float to double is allowed, but not double to float.
  • A floating-point value cannot be converted to an integer type.
  • An integer value cannot be converted to a floating-point type.


void fun(double val, int val2) {

    int x2 = val;    // if val == 7.9, x2 becomes 7 (bad)

    char c2 = val2;  // if val2 == 1025, c2 becomes 1 (bad)

    int x3 {val};    // error: possible truncation (good)

    char c3 {val2};  // error: possible narrowing (good)

    char c4 {24};    // OK: 24 can be represented exactly as a char (good)

    char c5 {264};   // error (assuming 8-bit chars): 264 cannot be 
                     // represented as a char (good)

    int x4 {2.0};    // error: no double to int value conversion (good)


The only situation where = is preferred over {} is when using auto keyword to get the type determined by the initializer.


auto z1 {99};   // z1 is an int
auto z2 = {99}; // z2 is std::initializer_list<int>
auto z3 = 99;   // z3 is an int


Prefer {} initialization over alternatives unless you have a strong reason not to.

jQuery UI: Datepicker set year range dropdown to 100 years

This is a bit late in the day for suggesting this, given how long ago the original question was posted, but this is what I did.

I needed a range of 70 years, which, while not as much as 100, is still too many years for the visitor to scroll through. (jQuery does step through year in groups, but that's a pain in the patootie for most people.)

The first step was to modify the JavaScript for the datepicker widget: Find this code in jquery-ui.js or jquery-ui-min.js (where it will be minimized):

for (a.yearshtml+='<select class="ui-datepicker-year" onchange="DP_jQuery_'+y+".datepicker._selectMonthYear('#"+"', this, 'Y');\" onclick=\"DP_jQuery_"+y+".datepicker._clickMonthYear('#""');\">";b<=g;b++)
 a.yearshtml+='<option value="'+b+'"'+(b==c?' selected="selected"':"")+">"+b+"</option>";

And replace it with this:

a.yearshtml+='<select class="ui-datepicker-year" onchange="DP_jQuery_'+y+
 ".datepicker._selectMonthYear('#""', this, 'Y');
 \" onclick=\"DP_jQuery_"+y+".datepicker._clickMonthYear('#""');
for(opg=-1;b<=g;b++) {
    a.yearshtml+=((b%10)==0 || opg==-1 ?
        (opg==1 ? (opg=0, '</optgroup>') : '')+
        (b<(g-10) ? (opg=1, '<optgroup label="'+b+' >">') : '') : '')+
        '<option value="'+b+'"'+(b==c?' selected="selected"':"")+">"+b+"</option>";

This surrounds the decades (except for the current) with OPTGROUP tags.

Next, add this to your CSS file:

.ui-datepicker OPTGROUP { font-weight:normal; }
.ui-datepicker OPTGROUP OPTION { display:none; text-align:right; }
.ui-datepicker OPTGROUP:hover OPTION { display:block; }

This hides the decades until the visitor mouses over the base year. Your visitor can scroll through any number of years quickly.

Feel free to use this; just please give proper attribution in your code.

What's wrong with nullable columns in composite primary keys?

NULL == NULL -> false (at least in DBMSs)

So you wouldn't be able to retrieve any relationships using a NULL value even with additional columns with real values.

Sending HTML Code Through JSON

All these answers didn't work for me.

But this one did:

json_encode($array, JSON_HEX_QUOT | JSON_HEX_TAG);

Thanks to this answer.

Java decimal formatting using String.format?

You want java.text.DecimalFormat.

DecimalFormat df = new DecimalFormat("0.00##");
String result = df.format(34.4959);

css divide width 100% to 3 column

Just in case someone is still looking for the answer,

let the browser take care of that. Try this:

  • display: table on the container element.
  • display: table-cell on the child elements.

The browser will evenly divide it whether you have 3 or 10 columns.


the container element should also have: table-layout: fixed otherwise the browser will determine the width of each element (most of the time not that bad).

LINQ extension methods - Any() vs. Where() vs. Exists()

context.Authors.Where(a => a.Books.Any(b => b.BookID == bookID)).ToList();

a.Books is the list of books by that author. The property is automatically created by Linq-to-Sql, provided you have a foreign-key relationship set up.

So, a.Books.Any(b => b.BookID == bookID) translates to "Do any of the books by this author have an ID of bookID", which makes the complete expression "Who are the authors of the book with id bookID?"

That could also be written something like

  from a in context.Authors
  join b in context.Books on a.AuthorId equal b.AuthorID
  where b.BookID == bookID
  select a;

UPDATE: Any() as far as I know, only returns a bool. Its effective implementation is:

 public Any(this IEnumerable<T> coll, Func<T, bool> predicate)
     foreach(T t in coll)
         if (predicte(t))
            return true;
     return false;