Programs & Examples On #Safecontrols

Limit to 2 decimal places with a simple pipe

Well now will be different after angular 5:

{{ number | currency :'GBP':'symbol':'1.2-2' }}

Circle-Rectangle collision detection (intersection)

To visualise, take your keyboard's numpad. If the key '5' represents your rectangle, then all the keys 1-9 represent the 9 quadrants of space divided by the lines that make up your rectangle (with 5 being the inside.)

1) If the circle's center is in quadrant 5 (i.e. inside the rectangle) then the two shapes intersect.

With that out of the way, there are two possible cases: a) The circle intersects with two or more neighboring edges of the rectangle. b) The circle intersects with one edge of the rectangle.

The first case is simple. If the circle intersects with two neighboring edges of the rectangle, it must contain the corner connecting those two edges. (That, or its center lies in quadrant 5, which we have already covered. Also note that the case where the circle intersects with only two opposing edges of the rectangle is covered as well.)

2) If any of the corners A, B, C, D of the rectangle lie inside the circle, then the two shapes intersect.

The second case is trickier. We should make note of that it may only happen when the circle's center lies in one of the quadrants 2, 4, 6 or 8. (In fact, if the center is on any of the quadrants 1, 3, 7, 8, the corresponding corner will be the closest point to it.)

Now we have the case that the circle's center is in one of the 'edge' quadrants, and it only intersects with the corresponding edge. Then, the point on the edge that is closest to the circle's center, must lie inside the circle.

3) For each line AB, BC, CD, DA, construct perpendicular lines p(AB,P), p(BC,P), p(CD,P), p(DA,P) through the circle's center P. For each perpendicular line, if the intersection with the original edge lies inside the circle, then the two shapes intersect.

There is a shortcut for this last step. If the circle's center is in quadrant 8 and the edge AB is the top edge, the point of intersection will have the y-coordinate of A and B, and the x-coordinate of center P.

You can construct the four line intersections and check if they lie on their corresponding edges, or find out which quadrant P is in and check the corresponding intersection. Both should simplify to the same boolean equation. Be wary of that the step 2 above did not rule out P being in one of the 'corner' quadrants; it just looked for an intersection.

Edit: As it turns out, I have overlooked the simple fact that #2 is a subcase of #3 above. After all, corners too are points on the edges. See @ShreevatsaR's answer below for a great explanation. And in the meanwhile, forget #2 above unless you want a quick but redundant check.

"%%" and "%/%" for the remainder and the quotient

In R, you can assign your own operators using %[characters]%. A trivial example:

'%p%' <- function(x, y){x^2 + y}

2 %p% 3 # result: 7

While I agree with BlueTrin that %% is pretty standard, I have a suspicion %/% may have something to do with the sort of operator definitions I showed above - perhaps it was easier to implement, and makes sense: %/% means do a special sort of division (integer division)

Get properties of a class

Some answers are partially wrong, and some facts in them are partially wrong as well.

Answer your question: Yes! You can.

In Typescript

class A {
    private a1;
    private a2;


}

Generates the following code in Javascript:

var A = /** @class */ (function () {
    function A() {
    }
    return A;
}());

as @Erik_Cupal said, you could just do:

let a = new A();
let array = return Object.getOwnPropertyNames(a);

But this is incomplete. What happens if your class has a custom constructor? You need to do a trick with Typescript because it will not compile. You need to assign as any:

let className:any = A;
let a = new className();// the members will have value undefined

A general solution will be:

class A {
    private a1;
    private a2;
    constructor(a1:number, a2:string){
        this.a1 = a1;
        this.a2 = a2;
    }
}

class Describer{

   describeClass( typeOfClass:any){
       let a = new typeOfClass();
       let array = Object.getOwnPropertyNames(a);
       return array;//you can apply any filter here
   }
}

For better understanding this will reference depending on the context.

Search for an item in a Lua list

This is a swiss-armyknife function you can use:

function table.find(t, val, recursive, metatables, keys, returnBool)
    if (type(t) ~= "table") then
        return nil
    end

    local checked = {}
    local _findInTable
    local _checkValue
    _checkValue = function(v)
        if (not checked[v]) then
            if (v == val) then
                return v
            end
            if (recursive and type(v) == "table") then
                local r = _findInTable(v)
                if (r ~= nil) then
                    return r
                end
            end
            if (metatables) then
                local r = _checkValue(getmetatable(v))
                if (r ~= nil) then
                    return r
                end
            end
            checked[v] = true
        end
        return nil
    end
    _findInTable = function(t)
        for k,v in pairs(t) do
            local r = _checkValue(t, v)
            if (r ~= nil) then
                return r
            end
            if (keys) then
                r = _checkValue(t, k)
                if (r ~= nil) then
                    return r
                end
            end
        end
        return nil
    end

    local r = _findInTable(t)
    if (returnBool) then
        return r ~= nil
    end
    return r
end

You can use it to check if a value exists:

local myFruit = "apple"
if (table.find({"apple", "pear", "berry"}, myFruit)) then
    print(table.find({"apple", "pear", "berry"}, myFruit)) -- 1

You can use it to find the key:

local fruits = {
    apple = {color="red"},
    pear = {color="green"},
}
local myFruit = fruits.apple
local fruitName = table.find(fruits, myFruit)
print(fruitName) -- "apple"

I hope the recursive parameter speaks for itself.

The metatables parameter allows you to search metatables as well.

The keys parameter makes the function look for keys in the list. Of course that would be useless in Lua (you can just do fruits[key]) but together with recursive and metatables, it becomes handy.

The returnBool parameter is a safe-guard for when you have tables that have false as a key in a table (Yes that's possible: fruits = {false="apple"})

Execute JavaScript using Selenium WebDriver in C#

The shortest code

ChromeDriver drv = new ChromeDriver();

drv.Navigate().GoToUrl("https://stackoverflow.com/questions/6229769/execute-javascript-using-selenium-webdriver-in-c-sharp");

drv.ExecuteScript("return alert(document.title);");


Eclipse+Maven src/main/java not visible in src folder in Package Explorer

If none of the answers worked for you. You might be in the wrong "Window". I was in "Package explorer" and switching to "Project Explorer" showed me the folders.

How to check for an active Internet connection on iOS or macOS?

Import Reachable.h class in your ViewController, and use the following code to check connectivity:

#define hasInternetConnection [[Reachability reachabilityForInternetConnection] isReachable]
if (hasInternetConnection){
      // To-do block
}

Hashing a file in Python

import hashlib
user = input("Enter ")
h = hashlib.md5(user.encode())
h2 = h.hexdigest()
with open("encrypted.txt","w") as e:
    print(h2,file=e)


with open("encrypted.txt","r") as e:
    p = e.readline().strip()
    print(p)

How to bring a window to the front?

I had the same problem with bringing a JFrame to the front under Ubuntu (Java 1.6.0_10). And the only way I could resolve it is by providing a WindowListener. Specifically, I had to set my JFrame to always stay on top whenever toFront() is invoked, and provide windowDeactivated event handler to setAlwaysOnTop(false).


So, here is the code that could be placed into a base JFrame, which is used to derive all application frames.

@Override
public void setVisible(final boolean visible) {
  // make sure that frame is marked as not disposed if it is asked to be visible
  if (visible) {
      setDisposed(false);
  }
  // let's handle visibility...
  if (!visible || !isVisible()) { // have to check this condition simply because super.setVisible(true) invokes toFront if frame was already visible
      super.setVisible(visible);
  }
  // ...and bring frame to the front.. in a strange and weird way
  if (visible) {
      toFront();
  }
}

@Override
public void toFront() {
  super.setVisible(true);
  int state = super.getExtendedState();
  state &= ~JFrame.ICONIFIED;
  super.setExtendedState(state);
  super.setAlwaysOnTop(true);
  super.toFront();
  super.requestFocus();
  super.setAlwaysOnTop(false);
}

Whenever your frame should be displayed or brought to front call frame.setVisible(true).

Since I moved to Ubuntu 9.04 there seems to be no need in having a WindowListener for invoking super.setAlwaysOnTop(false) -- as can be observed; this code was moved to the methods toFront() and setVisible().

Please note that method setVisible() should always be invoked on EDT.

Possible to iterate backwards through a foreach?

It is possible if you can change the collection code that implements IEnumerable or IEnumerable (e.g. your own implementation of IList).

Create an Iterator doing this job for you, for example like the following implementation through the IEnumerable interface (assuming 'items' is a List field in this sample):

public IEnumerator<TObject> GetEnumerator()
{
    for (var i = items.Count - 1; i >= 0; i--)
    { 
        yield return items[i];
    }
}

IEnumerator IEnumerable.GetEnumerator()
{
    return GetEnumerator();
}

Because of this your List will iterate in reverse order through your list.

Just a hint: You should clearly state this special behaviour of your list within the documentation (even better by choosing a self-explaining class name like Stack or Queue, too).

Best Practice: Initialize JUnit class fields in setUp() or at declaration?

I started digging myself and I found one potential advantage of using setUp(). If any exceptions are thrown during the execution of setUp(), JUnit will print a very helpful stack trace. On the other hand, if an exception is thrown during object construction, the error message simply says JUnit was unable to instantiate the test case and you don't see the line number where the failure occurred, probably because JUnit uses reflection to instantiate the test classes.

None of this applies to the example of creating an empty collection, since that will never throw, but it is an advantage of the setUp() method.

How to get a particular date format ('dd-MMM-yyyy') in SELECT query SQL Server 2008 R2

select convert(varchar(11), transfer_date, 106)

got me my desired result of date formatted as 07 Mar 2018

My column transfer_date is a datetime type column and I am using SQL Server 2017 on azure

Check if xdebug is working

Just to extend KsaRs answer and provide a possibility to check xdebug from command line:

php -r "echo (extension_loaded('xdebug') ? '' : 'non '), 'exists';"

Your project contains error(s), please fix it before running it

Is there a way to ignore existing errors in project. Something similar what eclipse allows in case of java projects.

In my case the errors exist in jni directory. The errors are shown even though ndk-buid succeeds. So all i want to do is to ignore the errors reported by eclipse.

If the errors are indeed errors then i should get unresolved symbols during ndk-build.

I have ensured standard android includes are there in include path.

Also my project is of type android/c/c++.

I have two builders associated with the project 1. statndard android builder 2. custom ndk builder that ive explicitly created.

need to add a class to an element

You are missing a closing h2 tag. It should be:

<h2><!-- Content --></h2> 

How to get a function name as a string?

You just want to get the name of the function here is a simple code for that. let say you have these functions defined

def function1():
    print "function1"

def function2():
    print "function2"

def function3():
    print "function3"
print function1.__name__

the output will be function1

Now let say you have these functions in a list

a = [function1 , function2 , funciton3]

to get the name of the functions

for i in a:
    print i.__name__

the output will be

function1
function2
function3

What is the use of a private static variable in Java?

Static variables have a single value for all instances of a class.

If you were to make something like:

public class Person
{
    private static int numberOfEyes;
    private String name;
}

and then you wanted to change your name, that is fine, my name stays the same. If, however you wanted to change it so that you had 17 eyes then everyone in the world would also have 17 eyes.

Decompile an APK, modify it and then recompile it

Thanks to Chris Jester-Young I managed to make it work!

I think the way I managed to do it will work only on really simple projects:

  • With Dex2jar I obtained the Jar.
  • With jd-gui I convert my Jar back to Java files.
  • With apktool i got the android manifest and the resources files.

  • In Eclipse I create a new project with the same settings as the old one (checking all the information in the manifest file)

  • When the project is created I'm replacing all the resources and the manifest with the ones I obtained with apktool
  • I paste the java files I extracted from the Jar in the src folder (respecting the packages)
  • I modify those files with what I need
  • Everything is compiling!

/!\ be sure you removed the old apk from the device an error will be thrown stating that the apk signature is not the same as the old one!

how to get files from <input type='file' .../> (Indirect) with javascript

If you are looking to style a file input element, look at open file dialog box in javascript. If you are looking to grab the files associated with a file input element, you must do something like this:

inputElement.onchange = function(event) {
   var fileList = inputElement.files;
   //TODO do something with fileList.  
}

See this MDN article for more info on the FileList type.

Note that the code above will only work in browsers that support the File API. For IE9 and earlier, for example, you only have access to the file name. The input element has no files property in non-File API browsers.

How to export all collections in MongoDB?

I wrote bash script for that. Just run it with 2 parameters (database name, dir to store files).

#!/bin/bash

if [ ! $1 ]; then
        echo " Example of use: $0 database_name [dir_to_store]"
        exit 1
fi
db=$1
out_dir=$2
if [ ! $out_dir ]; then
        out_dir="./"
else
        mkdir -p $out_dir
fi

tmp_file="fadlfhsdofheinwvw.js"
echo "print('_ ' + db.getCollectionNames())" > $tmp_file
cols=`mongo $db $tmp_file | grep '_' | awk '{print $2}' | tr ',' ' '`
for c in $cols
do
    mongoexport -d $db -c $c -o "$out_dir/exp_${db}_${c}.json"
done
rm $tmp_file

How to abort makefile if variable not set?

Use the shell error handling for unset variables (note the double $):

$ cat Makefile
foo:
        echo "something is set to $${something:?}"

$ make foo
echo "something is set to ${something:?}"
/bin/sh: something: parameter null or not set
make: *** [foo] Error 127


$ make foo something=x
echo "something is set to ${something:?}"
something is set to x

If you need a custom error message, add it after the ?:

$ cat Makefile
hello:
        echo "hello $${name:?please tell me who you are via \$$name}"

$ make hello
echo "hello ${name:?please tell me who you are via \$name}"
/bin/sh: name: please tell me who you are via $name
make: *** [hello] Error 127

$ make hello name=jesus
echo "hello ${name:?please tell me who you are via \$name}"
hello jesus

Why calling react setState method doesn't mutate the state immediately?

You could try using ES7 async/await. For instance using your example:

handleChange: async function(event) {
    console.log(this.state.value);
    await this.setState({value: event.target.value});
    console.log(this.state.value);
}

Pythonically add header to a csv file

This worked for me.

header = ['row1', 'row2', 'row3']
some_list = [1, 2, 3]
with open('test.csv', 'wt', newline ='') as file:
    writer = csv.writer(file, delimiter=',')
    writer.writerow(i for i in header)
    for j in some_list:
        writer.writerow(j)

Reading a text file and splitting it into single words in python

Here is my totally functional approach which avoids having to read and split lines. It makes use of the itertools module:

Note for python 3, replace itertools.imap with map

import itertools

def readwords(mfile):
    byte_stream = itertools.groupby(
        itertools.takewhile(lambda c: bool(c),
            itertools.imap(mfile.read,
                itertools.repeat(1))), str.isspace)

    return ("".join(group) for pred, group in byte_stream if not pred)

Sample usage:

>>> import sys
>>> for w in readwords(sys.stdin):
...     print (w)
... 
I really love this new method of reading words in python
I
really
love
this
new
method
of
reading
words
in
python
           
It's soo very Functional!
It's
soo
very
Functional!
>>>

I guess in your case, this would be the way to use the function:

with open('words.txt', 'r') as f:
    for word in readwords(f):
        print(word)

How to activate "Share" button in android app?

Share Any File as below ( Kotlin ) :
first create a folder named xml in the res folder and create a new XML Resource File named provider_paths.xml and put the below code inside it :

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <files-path
        name="files"
        path="."/>

    <external-path
        name="external_files"
        path="."/>
</paths>

now go to the manifests folder and open the AndroidManifest.xml and then put the below code inside the <application> tag :

<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
    android:name="android.support.FILE_PROVIDER_PATHS"
    android:resource="@xml/provider_paths" /> // provider_paths.xml file path in this example
</provider>

now you put the below code in the setOnLongClickListener :

share_btn.setOnClickListener {
    try {
        val file = File("pathOfFile")
        if(file.exists()) {
            val uri = FileProvider.getUriForFile(this, BuildConfig.APPLICATION_ID + ".provider", file)
            val intent = Intent(Intent.ACTION_SEND)
            intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
            intent.setType("*/*")
            intent.putExtra(Intent.EXTRA_STREAM, uri)
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent)
        }
    } catch (e: java.lang.Exception) {
        e.printStackTrace()
        toast("Error")
    }
}

String length in bytes in JavaScript

There is no way to do it in JavaScript natively. (See Riccardo Galli's answer for a modern approach.)


For historical reference or where TextEncoder APIs are still unavailable.

If you know the character encoding, you can calculate it yourself though.

encodeURIComponent assumes UTF-8 as the character encoding, so if you need that encoding, you can do,

function lengthInUtf8Bytes(str) {
  // Matches only the 10.. bytes that are non-initial characters in a multi-byte sequence.
  var m = encodeURIComponent(str).match(/%[89ABab]/g);
  return str.length + (m ? m.length : 0);
}

This should work because of the way UTF-8 encodes multi-byte sequences. The first encoded byte always starts with either a high bit of zero for a single byte sequence, or a byte whose first hex digit is C, D, E, or F. The second and subsequent bytes are the ones whose first two bits are 10. Those are the extra bytes you want to count in UTF-8.

The table in wikipedia makes it clearer

Bits        Last code point Byte 1          Byte 2          Byte 3
  7         U+007F          0xxxxxxx
 11         U+07FF          110xxxxx        10xxxxxx
 16         U+FFFF          1110xxxx        10xxxxxx        10xxxxxx
...

If instead you need to understand the page encoding, you can use this trick:

function lengthInPageEncoding(s) {
  var a = document.createElement('A');
  a.href = '#' + s;
  var sEncoded = a.href;
  sEncoded = sEncoded.substring(sEncoded.indexOf('#') + 1);
  var m = sEncoded.match(/%[0-9a-f]{2}/g);
  return sEncoded.length - (m ? m.length * 2 : 0);
}

What's the best practice to "git clone" into an existing folder?

If you are using at least git 1.7.7 (which taught clone the --config option), to turn the current directory into a working copy:

git clone example.com/my.git ./.git --mirror --config core.bare=false

This works by:

  • Cloning the repository into a new .git folder
  • --mirror makes the new clone into a purely metadata folder as .git needs to be
  • --config core.bare=false countermands the implicit bare=true of the --mirror option, thereby allowing the repository to have an associated working directory and act like a normal clone

This obviously won't work if a .git metadata directory already exists in the directory you wish to turn into a working copy.

Convert number to month name in PHP

This is how I did it

// sets Asia/Calcutta time zone
date_default_timezone_set("Asia/Calcutta");

//fetches current date and time
$date = date("Y-m-d H:i:s");

$dateArray = date_parse_from_format('Y/m/d', $date);
$month = DateTime::createFromFormat('!m', $dateArray['month'])->format('F');
$dateString = $dateArray['day'] . " " . $month  . " " . $dateArray['year'];

echo $dateString;

returns 30 June 2019

Using sed, how do you print the first 'N' characters of a line?

Don't use sed, use cut:

grep .... | cut -c 1-N

If you MUST use sed:

grep ... | sed -e 's/^\(.\{12\}\).*/\1/'

Conditional step/stage in Jenkins pipeline

Doing the same in declarative pipeline syntax, below are few examples:

stage('master-branch-stuff') {
    when {
        branch 'master'
    }
    steps {
        echo 'run this stage - ony if the branch = master branch'
    }
}

stage('feature-branch-stuff') {
    when {
        branch 'feature/*'
    }
    steps {
        echo 'run this stage - only if the branch name started with feature/'
    }
}

stage('expression-branch') {
    when {
        expression {
            return env.BRANCH_NAME != 'master';
        }
    }
    steps {
        echo 'run this stage - when branch is not equal to master'
    }
}

stage('env-specific-stuff') {
    when { 
        environment name: 'NAME', value: 'this' 
    }
    steps {
        echo 'run this stage - only if the env name and value matches'
    }
}

More effective ways coming up - https://issues.jenkins-ci.org/browse/JENKINS-41187
Also look at - https://jenkins.io/doc/book/pipeline/syntax/#when


The directive beforeAgent true can be set to avoid spinning up an agent to run the conditional, if the conditional doesn't require git state to decide whether to run:

when { beforeAgent true; expression { return isStageConfigured(config) } }

Release post and docs


UPDATE
New WHEN Clause
REF: https://jenkins.io/blog/2018/04/09/whats-in-declarative

equals - Compares two values - strings, variables, numbers, booleans - and returns true if they’re equal. I’m honestly not sure how we missed adding this earlier! You can do "not equals" comparisons using the not { equals ... } combination too.

changeRequest - In its simplest form, this will return true if this Pipeline is building a change request, such as a GitHub pull request. You can also do more detailed checks against the change request, allowing you to ask "is this a change request against the master branch?" and much more.

buildingTag - A simple condition that just checks if the Pipeline is running against a tag in SCM, rather than a branch or a specific commit reference.

tag - A more detailed equivalent of buildingTag, allowing you to check against the tag name itself.

Laravel Eloquent "WHERE NOT IN"

You can use WhereNotIn in the following way:

$category=DB::table('category')
          ->whereNotIn('category_id',[14 ,15])
          ->get();`enter code here`

Animate element transform rotate

As far as I know, basic animates can't animate non-numeric CSS properties.

I believe you could get this done using a step function and the appropriate css3 transform for the users browser. CSS3 transform is a bit tricky to cover all your browsers in (IE6 you need to use the Matrix filter, for instance).

EDIT: here's an example that works in webkit browsers (Chrome, Safari): http://jsfiddle.net/ryleyb/ERRmd/

If you wanted to support IE9 only, you could use transform instead of -webkit-transform, or -moz-transform would support FireFox.

The trick used is to animate a CSS property we don't care about (text-indent) and then use its value in a step function to do the rotation:

$('#foo').animate(
..
step: function(now,fx) {
  $(this).css('-webkit-transform','rotate('+now+'deg)'); 
}
...

Disable Buttons in jQuery Mobile

What seems to be needed is to actually define the button as a button widget.

I had the same problem (in beta 1)

I did

$("#submitButton").button();

in my window ready handler, after that it worked to do as it is said in the docs, i.e.:

$("#submitButton").button('disable'); 

I guess this has to do with that jqm is converting the markup, but isnt actually instatiating a real button widget for buttons and link buttons.

Is it a bad practice to use an if-statement without curly braces?

The "rule" I follow is this:

If the "if" statement is testing in order to do something (I.E. call functions, configure variables etc.), use braces.

if($test)
{
    doSomething();
}

This is because I feel you need to make it clear what functions are being called and where the flow of the program is going, under what conditions. Having the programmer understand exactly what functions are called and what variables are set in this condition is important to helping them understand exactly what your program is doing.

If the "if" statement is testing in order to stop doing something (I.E. flow control within a loop or function), use a single line.

if($test) continue;
if($test) break;
if($test) return;

In this case, what's important to the programmer is discovering quickly what the exceptional cases are where you don't want the code to run, and that is all coverred in $test, not in the execution block.

How to select following sibling/xml tag using xpath

For completeness - adding to accepted answer above - in case you are interested in any sibling regardless of the element type you can use variation:

following-sibling::*

Windows Batch: How to add Host-Entries?

Sometime I have to work from home and connect to office through vpn. Internal domain names should be resolved to different IPs at home. There are several names that have to be changed between office and home. For example:

At office, a => 192.168.0.3, b => 192.168.0.52. 
At home, a => 10.6.1.7, b => 10.4.5.23. 

My solution is to create two files: C:\WINDOWS\system32\drivers\etc\hosts-home and C:\WINDOWS\system32\drivers\etc\hosts-office. Each of them contains set of name-to-IP mapping. From Administrator PowerShell, When I work at the office, execute

C:\WINDOWS\system32> cp .\drivers\etc\hosts-office .\drivers\etc\hosts

When I arrive at home, execute

C:\WINDOWS\system32> cp .\drivers\etc\hosts-home .\drivers\etc\hosts

Download text/csv content as files from server in Angular

Most of the references on the web about this issue point out to the fact that you cannot download files via ajax call 'out of the box'. I have seen (hackish) solutions that involve iframes and also solutions like @dcodesmith's that work and are perfectly viable.

Here's another solution I found that works in Angular and is very straighforward.

In the view, wrap the csv download button with <a> tag the following way :

<a target="_self" ng-href="{{csv_link}}">
  <button>download csv</button>
</a>

(Notice the target="_self there, it's crucial to disable Angular's routing inside the ng-app more about it here)

Inside youre controller you can define csv_link the following way :

$scope.csv_link = '/orders' + $window.location.search;

(the $window.location.search is optional and onlt if you want to pass additionaly search query to your server)

Now everytime you click the button, it should start downloading.

Warning: "continue" targeting switch is equivalent to "break". Did you mean to use "continue 2"?

The issue looks to me to be a backward incompatibility with PHP 7.3 for the continue keyword in Switch statements. Take a look at the "Continue Targeting Switch issues Warning" section in Backward Incompatible Changes.

I ran into the same issue with Symfony 3.3 using PHP 7.3 and downgrading to PHP 7.2 resolved the warning.

How can I get dictionary key as variable directly in Python (not by searching from value)?

If you want to access both the key and value, use the following:

Python 2:

for key, value in my_dict.iteritems():
    print(key, value)

Python 3:

for key, value in my_dict.items():
    print(key, value)

PHP code is not being executed, instead code shows on the page

I'm running Apache on Ubuntu and my issue was that the /etc/apache2/mods-available/php5.conf file was missing this:

<FilesMatch ".+\.ph(p[345]?|t|tml)$">
    SetHandler application/x-httpd-php
</FilesMatch>

I added it back in and php was parsing php files correctly.

How do I POST with multipart form data using fetch?

You're setting the Content-Type to be multipart/form-data, but then using JSON.stringify on the body data, which returns application/json. You have a content type mismatch.

You will need to encode your data as multipart/form-data instead of json. Usually multipart/form-data is used when uploading files, and is a bit more complicated than application/x-www-form-urlencoded (which is the default for HTML forms).

The specification for multipart/form-data can be found in RFC 1867.

For a guide on how to submit that kind of data via javascript, see here.

The basic idea is to use the FormData object (not supported in IE < 10):

async function sendData(url, data) {
  const formData  = new FormData();

  for(const name in data) {
    formData.append(name, data[name]);
  }

  const response = await fetch(url, {
    method: 'POST',
    body: formData
  });

  // ...
}

Per this article make sure not to set the Content-Type header. The browser will set it for you, including the boundary parameter.

How do you run a command as an administrator from the Windows command line?

A batch/WSH hybrid is able to call ShellExecute to display the UAC elevation dialog...

@if (1==1) @if(1==0) @ELSE
@echo off&SETLOCAL ENABLEEXTENSIONS
>nul 2>&1 "%SYSTEMROOT%\system32\cacls.exe" "%SYSTEMROOT%\system32\config\system"||(
    cscript //E:JScript //nologo "%~f0"
    @goto :EOF
)
echo.Performing admin tasks...
REM call foo.exe
@goto :EOF
@end @ELSE
ShA=new ActiveXObject("Shell.Application")
ShA.ShellExecute("cmd.exe","/c \""+WScript.ScriptFullName+"\"","","runas",5);
@end

Mongod complains that there is no /data/db folder

To fix that error on OS X, I restarted and stopped the service: $ brew services restart mongodb $ brew services stop mongodb

Then I ran mongod --config /usr/local/etc/mongod.conf, and the problem was gone.

The error seemed to arise after upgrading the mongodb homebrew package.

Check input value length

You can add a form onsubmit handler, something like:

<form onsubmit="return validate();">

</form>


<script>function validate() {
 // check if input is bigger than 3
 var value = document.getElementById('titleeee').value;
 if (value.length < 3) {
   return false; // keep form from submitting
 }

 // else form is good let it submit, of course you will 
 // probably want to alert the user WHAT went wrong.

 return true;
}</script>

Bring a window to the front in WPF

Well, since this is such a hot topic... here is what works for me. I got errors if I didn't do it this way because Activate() will error out on you if you cannot see the window.

Xaml:

<Window .... 
        Topmost="True" 
        .... 
        ContentRendered="mainWindow_ContentRendered"> .... </Window>

Codebehind:

private void mainWindow_ContentRendered(object sender, EventArgs e)
{
    this.Topmost = false;
    this.Activate();
    _UsernameTextBox.Focus();
}

This was the only way for me to get the window to show on top. Then activate it so you can type in the box without having to set focus with the mouse. control.Focus() wont work unless the window is Active();

getApplication() vs. getApplicationContext()

To answer the question, getApplication() returns an Application object and getApplicationContext() returns a Context object. Based on your own observations, I would assume that the Context of both are identical (i.e. behind the scenes the Application class calls the latter function to populate the Context portion of the base class or some equivalent action takes place). It shouldn't really matter which function you call if you just need a Context.

Random strings in Python

try importing the below package from random import*

How to enumerate an enum with String type?

This post is relevant here https://www.swift-studies.com/blog/2014/6/10/enumerating-enums-in-swift

Essentially the proposed solution is

enum ProductCategory : String {
     case Washers = "washers", Dryers = "dryers", Toasters = "toasters"

     static let allValues = [Washers, Dryers, Toasters]
}

for category in ProductCategory.allValues{
     //Do something
}

Use table row coloring for cells in Bootstrap

With less you can set it up like this;

.table tbody tr {
    &.error > td { background-color: red !important; }
    &.error:hover > td { background-color: yellow !important; }
    &.success > td { background-color: green !important; }
    &.success:hover > td { background-color: yellow !important; }
    ...
}

That did the trick for me.

Regex to accept alphanumeric and some special character in Javascript?

I forgot to mention. This should also accept whitespace.

You could use:

/^[-@.\/#&+\w\s]*$/

Note how this makes use of the character classes \w and \s.

EDIT:- Added \ to escape /

Open Sublime Text from Terminal in macOS

Creating the file in the Default path did not work for me as the Menu.sublime-menu file has overridden almost all other menu options and left me with only the custom one.

What worked for me is creating the below file in path ~/Library/Application Support/Sublime Text 3/Packages/User/Main.sublime-menu (note directory User instead of Default):

[
    {
        "caption": "File",
        "mnemonic": "F",
        "id": "file",
        "children":
        [
            {
                "caption": "Open Recent More",
                "children":
                [
                    { "command": "open_recent_file", "args": {"index": 1 } },
                    { "command": "open_recent_file", "args": {"index": 2 } },
                    { "command": "open_recent_file", "args": {"index": 3 } },
                    { "command": "open_recent_file", "args": {"index": 4 } },
                    { "command": "open_recent_file", "args": {"index": 5 } },
                    { "command": "open_recent_file", "args": {"index": 6 } },
                    { "command": "open_recent_file", "args": {"index": 7 } },
                    { "command": "open_recent_file", "args": {"index": 8 } },
                    { "command": "open_recent_file", "args": {"index": 9 } },
                    { "command": "open_recent_file", "args": {"index": 10 } },
                    { "command": "open_recent_file", "args": {"index": 11 } },
                    { "command": "open_recent_file", "args": {"index": 12 } },
                    { "command": "open_recent_file", "args": {"index": 13 } },
                    { "command": "open_recent_file", "args": {"index": 14 } },
                    { "command": "open_recent_file", "args": {"index": 15 } },
                    { "command": "open_recent_file", "args": {"index": 16 } },
                    { "command": "open_recent_file", "args": {"index": 17 } },
                    { "command": "open_recent_file", "args": {"index": 18 } },
                    { "command": "open_recent_file", "args": {"index": 19 } },
                    { "command": "open_recent_file", "args": {"index": 20 } },
                    { "command": "open_recent_file", "args": {"index": 21 } },
                    { "command": "open_recent_file", "args": {"index": 22 } },
                    { "command": "open_recent_file", "args": {"index": 23 } },
                    { "command": "open_recent_file", "args": {"index": 24 } },
                    { "command": "open_recent_file", "args": {"index": 25 } },
                    { "command": "open_recent_file", "args": {"index": 26 } },
                    { "command": "open_recent_file", "args": {"index": 27 } },
                    { "command": "open_recent_file", "args": {"index": 28 } },
                    { "command": "open_recent_file", "args": {"index": 29 } },
                    { "command": "open_recent_file", "args": {"index": 30 } },
                    { "command": "open_recent_file", "args": {"index": 31 } },
                    { "command": "open_recent_file", "args": {"index": 32 } },
                    { "command": "open_recent_file", "args": {"index": 33 } },
                    { "command": "open_recent_file", "args": {"index": 34 } },
                    { "command": "open_recent_file", "args": {"index": 35 } },
                    { "command": "open_recent_file", "args": {"index": 36 } },
                    { "command": "open_recent_file", "args": {"index": 37 } },
                    { "command": "open_recent_file", "args": {"index": 38 } },
                    { "command": "open_recent_file", "args": {"index": 39 } },
                    { "command": "open_recent_file", "args": {"index": 40 } },
                    { "command": "open_recent_file", "args": {"index": 41 } },
                    { "command": "open_recent_file", "args": {"index": 42 } },
                    { "command": "open_recent_file", "args": {"index": 43 } },
                    { "command": "open_recent_file", "args": {"index": 44 } },
                    { "command": "open_recent_file", "args": {"index": 45 } },
                    { "command": "open_recent_file", "args": {"index": 46 } },
                    { "command": "open_recent_file", "args": {"index": 47 } },
                    { "command": "open_recent_file", "args": {"index": 48 } },
                    { "command": "open_recent_file", "args": {"index": 49 } },
                    { "command": "open_recent_file", "args": {"index": 50 } }
                ]
            }
        ]
    }
]

Result:

(needed to blur some parts of the image for security reasons)

open-recent-more.png

How to use Typescript with native ES6 Promises

I had to downgrade @types/core-js to 9.36 to get it to work with "target": "es5" set in my tsconfig.

"@types/core-js": "0.9.36",

Best/Most Comprehensive API for Stocks/Financial Data

Yahoo's api provides a CSV dump:

Example: http://finance.yahoo.com/d/quotes.csv?s=msft&f=price

I'm not sure if it is documented or not, but this code sample should showcase all of the features (namely the stat types [parameter f in the query string]. I'm sure you can find documentation (official or not) if you search for it.

http://www.goldb.org/ystockquote.html

Edit

I found some unofficial documentation:

http://ilmusaham.wordpress.com/tag/stock-yahoo-data/

NPM: npm-cli.js not found when running npm

Don't change any environment variables

It was the installer which caused the issue and did not install all the required file.

I just repaired the NODEJS setup on windows 7 and it works very well. May be you can reinstall, just incase something does not work.

Check that Field Exists with MongoDB

Suppose we have a collection like below:

{ 
  "_id":"1234"
  "open":"Yes"
  "things":{
             "paper":1234
             "bottle":"Available"
             "bottle_count":40
            } 
}

We want to know if the bottle field is present or not?

Ans:

db.products.find({"things.bottle":{"$exists":true}})

Solution to "subquery returns more than 1 row" error

use MAX in your SELECT to return on value.. EXAMPLE

INSERT INTO school_year_studentid (student_id,syr_id) VALUES
((SELECT MAX(student_id) FROM student), (SELECT MAX(syr_id) FROM school_year))

instead of

INSERT INTO school_year_studentid (student_id,syr_id) VALUES
((SELECT (student_id) FROM student), (SELECT (syr_id) FROM school_year))

try it without MAX it will more than one value

Download file inside WebView

    mwebView.setDownloadListener(new DownloadListener()
   {

  @Override  


   public void onDownloadStart(String url, String userAgent,
        String contentDisposition, String mimeType,
        long contentLength) {

    DownloadManager.Request request = new DownloadManager.Request(
            Uri.parse(url));


    request.setMimeType(mimeType);


    String cookies = CookieManager.getInstance().getCookie(url);


    request.addRequestHeader("cookie", cookies);


    request.addRequestHeader("User-Agent", userAgent);


    request.setDescription("Downloading file...");


    request.setTitle(URLUtil.guessFileName(url, contentDisposition,
            mimeType));


    request.allowScanningByMediaScanner();


    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
    request.setDestinationInExternalPublicDir(
            Environment.DIRECTORY_DOWNLOADS, URLUtil.guessFileName(
                    url, contentDisposition, mimeType));
    DownloadManager dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
    dm.enqueue(request);
    Toast.makeText(getApplicationContext(), "Downloading File",
            Toast.LENGTH_LONG).show();
}});

Allow 2 decimal places in <input type="number">

For currency, I'd suggest:

<div><label>Amount $
    <input type="number" placeholder="0.00" required name="price" min="0" value="0" step="0.01" title="Currency" pattern="^\d+(?:\.\d{1,2})?$" onblur="
this.parentNode.parentNode.style.backgroundColor=/^\d+(?:\.\d{1,2})?$/.test(this.value)?'inherit':'red'
"></label></div>

See http://jsfiddle.net/vx3axsk5/1/

The HTML5 properties "step", "min" and "pattern" will be validated when the form is submit, not onblur. You don't need the step if you have a pattern and you don't need a pattern if you have a step. So you could revert back to step="any" with my code since the pattern will validate it anyways.

If you'd like to validate onblur, I believe giving the user a visual cue is also helpful like coloring the background red. If the user's browser doesn't support type="number" it will fallback to type="text". If the user's browser doesn't support the HTML5 pattern validation, my JavaScript snippet doesn't prevent the form from submitting, but it gives a visual cue. So for people with poor HTML5 support, and people trying to hack into the database with JavaScript disabled or forging HTTP Requests, you need to validate on the server again anyways. The point with validation on the front-end is for a better user experience. So as long as most of your users have a good experience, it's fine to rely on HTML5 features provided the code will still works and you can validate on the back-end.

C# Macro definitions in Preprocessor

You can use a C preprocessor (like mcpp) and rig it into your .csproj file. Then you chnage "build action" on your source file from Compile to Preprocess or whatever you call it. Just add BeforBuild to your .csproj like this:

  <Target Name="BeforeBuild" Inputs="@(Preprocess)" Outputs="@(Preprocess->'%(Filename)_P.cs')">
<Exec Command="..\Bin\cpp.exe @(Preprocess) -P -o %(RelativeDir)%(Filename)_P.cs" />
<CreateItem Include="@(Preprocess->'%(RelativeDir)%(Filename)_P.cs')">
  <Output TaskParameter="Include" ItemName="Compile" />
</CreateItem>

You may have to manually change Compile to Preprocess on at least one file (in a text editor) - then the "Preprocess" option should be available for selection in Visual Studio.

I know that macros are heavily overused and misused but removing them completely is equally bad if not worse. A classic example of macro usage would be NotifyPropertyChanged. Every programmer who had to rewrite this code by hand thousands of times knows how painful it is without macros.

Getting checkbox values on submit

It's very simple.

The checkbox field is like an input text. If you don't write anything in the field, it will say the field doesn't exist.

<form method="post">
    <input type="checkbox" name="check">This is how it works!<br>
    <button type="submit" name="submit">Submit</button>
</form>
<?php
if(isset($_POST['submit'])) {
    if(!isset($_POST['check'])) {
        echo "Not selected!";
    }else{
        echo "Selected!";
    }
}
?>

Should I use Vagrant or Docker for creating an isolated environment?

If your purpose is the isolation, I think Docker is what you want.

Vagrant is a virtual machine manager. It allows you to script the virtual machine configuration as well as the provisioning. However, it is still a virtual machine depending on VirtualBox (or others) with a huge overhead. It requires you to have a hard drive file that can be huge, it takes a lot of ram, and performance may be not very good.

Docker on the other hand uses kernel cgroup and namespacing via LXC. It means that you are using the same kernel as the host and the same file system. You can use Dockerfile with the docker build command in order to handle the provisioning and configuration of your container. You have an example at docs.docker.com on how to make your Dockerfile; it is very intuitive.

The only reason you could want to use Vagrant is if you need to do BSD, Windows or other non-Linux development on your Ubuntu box. Otherwise, go for Docker.

Is there a difference between x++ and ++x in java?

I landed here from one of its recent dup's, and though this question is more than answered, I couldn't help decompiling the code and adding "yet another answer" :-)

To be accurate (and probably, a bit pedantic),

int y = 2;
y = y++;

is compiled into:

int y = 2;
int tmp = y;
y = y+1;
y = tmp;

If you javac this Y.java class:

public class Y {
    public static void main(String []args) {
        int y = 2;
        y = y++;
    }
}

and javap -c Y, you get the following jvm code (I have allowed me to comment the main method with the help of the Java Virtual Machine Specification):

public class Y extends java.lang.Object{
public Y();
  Code:
   0:   aload_0
   1:   invokespecial  #1; //Method java/lang/Object."<init>":()V
   4:   return

public static void main(java.lang.String[]);
  Code:
   0:   iconst_2 // Push int constant `2` onto the operand stack. 

   1:   istore_1 // Pop the value on top of the operand stack (`2`) and set the
                 // value of the local variable at index `1` (`y`) to this value.

   2:   iload_1  // Push the value (`2`) of the local variable at index `1` (`y`)
                 // onto the operand stack

   3:   iinc  1, 1 // Sign-extend the constant value `1` to an int, and increment
                   // by this amount the local variable at index `1` (`y`)

   6:   istore_1 // Pop the value on top of the operand stack (`2`) and set the
                 // value of the local variable at index `1` (`y`) to this value.
   7:   return

}

Thus, we finally have:

0,1: y=2
2: tmp=y
3: y=y+1
6: y=tmp

How to query values from xml nodes?

SELECT  b.BatchID,
        x.XmlCol.value('(ReportHeader/OrganizationReportReferenceIdentifier)[1]','VARCHAR(100)') AS OrganizationReportReferenceIdentifier,
        x.XmlCol.value('(ReportHeader/OrganizationNumber)[1]','VARCHAR(100)') AS OrganizationNumber
FROM    Batches b
CROSS APPLY b.RawXml.nodes('/CasinoDisbursementReportXmlFile/CasinoDisbursementReport') x(XmlCol);

Demo: SQLFiddle

How to test if JSON object is empty in Java

I have added isEmpty() methods on JSONObject and JSONArray()

 //on JSONObject 
 public Boolean isEmpty(){         
     return !this.keys().hasNext();
 }

...

//on JSONArray
public Boolean isEmpty(){
    return this.length()==0;        
}

you can get it here https://github.com/kommradHomer/JSON-java

Save Screen (program) output to a file

There is a command line option for logging. The output is saved to screenlog.n file, where n is a number of the screen. From man pages of screen:

‘-L’ Tell screen to turn on automatic output logging for the windows.

Apply global variable to Vuejs

If the global variable should not be written to by anything, including Vuejs, you can use Object.freeze to freeze your object. Adding it to Vue's viewmodel won't unfreeze it. Another option is to provide Vuejs with a frozen copy of the object, if the object is intended to be written globally but just not by Vue: var frozenCopy = Object.freeze(Object.assign({}, globalObject))

How to set the style -webkit-transform dynamically using JavaScript?

The JavaScript style names are WebkitTransformOrigin and WebkitTransform

element.style.webkitTransform = "rotate(-2deg)";

Check the DOM extension reference for WebKit here.

What is the canonical way to check for errors using the CUDA runtime API?

The solution discussed here worked well for me. This solution uses built-in cuda functions and is very simple to implement.

The relevant code is copied below:

#include <stdio.h>
#include <stdlib.h>

__global__ void foo(int *ptr)
{
  *ptr = 7;
}

int main(void)
{
  foo<<<1,1>>>(0);

  // make the host block until the device is finished with foo
  cudaDeviceSynchronize();

  // check for error
  cudaError_t error = cudaGetLastError();
  if(error != cudaSuccess)
  {
    // print the CUDA error message and exit
    printf("CUDA error: %s\n", cudaGetErrorString(error));
    exit(-1);
  }

  return 0;
}

What is console.log?

console.log specifically is a method for developers to write code to inconspicuously inform the developers what the code is doing. It can be used to alert you that there's an issue, but shouldn't take the place of an interactive debugger when it comes time to debug the code. Its asynchronous nature means that the logged values don't necessarily represent the value when the method was called.

In short: log errors with console.log (if available), then fix the errors using your debugger of choice: Firebug, WebKit Developer Tools (built-in to Safari and Chrome), IE Developer Tools or Visual Studio.

APK signing error : Failed to read key from keystore

For someone not using the signing configs and trying to test out the Cordova Release command by typing all the parameters at command line, you may need to enclose your passwords with single quotes if you have special characters in your password

cordova run android --release -- --keystore=../my-release-key.keystore --storePassword='password' --alias=alias_name --password='password'

How SID is different from Service name in Oracle tnsnames.ora

As per Oracle Glossary :

SID is a unique name for an Oracle database instance. ---> To switch between Oracle databases, users must specify the desired SID <---. The SID is included in the CONNECT DATA parts of the connect descriptors in a TNSNAMES.ORA file, and in the definition of the network listener in the LISTENER.ORA file. Also known as System ID. Oracle Service Name may be anything descriptive like "MyOracleServiceORCL". In Windows, You can your Service Name running as a service under Windows Services.

You should use SID in TNSNAMES.ORA as a better approach.

Is there a way to make HTML5 video fullscreen?

An alternative solution would be to have to browser simply provide this option on the contextual menu. No need to have Javascript to do this, though I could see when it would be useful.

In the mean time an alternative solution would simply be to maximise the window (Javascript can provide screen dimensions) and then maximise the video within it. Give it a go and then simply see if the results are acceptable to your users.

How to bring back "Browser mode" in IE11?

Easiest way, especially if in MSDN,,wasted hours of my time, stupid MS

http://support.microsoft.com/kb/2900662/en-us?sd=rss

  1. Open the Developer Tools pane. To do this, press F12.
  2. Open the Emulation screen. To do this, press Ctrl+8.
  3. On the Document mode list under Mode, click 9.
  4. On the User agent string list under Mode, click Internet Explorer 9.

how to "execute" make file

As paxdiablo said make -f pax.mk would execute the pax.mk makefile, if you directly execute it by typing ./pax.mk, then you would get syntax error.

Also you can just type make if your file name is makefile/Makefile.

Suppose you have two files named makefile and Makefile in the same directory then makefile is executed if make alone is given. You can even pass arguments to makefile.

Check out more about makefile at this Tutorial : Basic understanding of Makefile

split string only on first instance - java

String[] func(String apple){
String[] tmp = new String[2];
for(int i=0;i<apple.length;i++){
   if(apple.charAt(i)=='='){
      tmp[0]=apple.substring(0,i);
      tmp[1]=apple.substring(i+1,apple.length);
      break;
   }
}
return tmp;
}
//returns string_ARRAY_!

i like writing own methods :)

Change directory command in Docker?

RUN git clone http://username:password@url/example.git
WORKDIR /folder
RUN make

PHP - add 1 day to date format mm-dd-yyyy

$date = DateTime::createFromFormat('m-d-Y', '04-15-2013');
$date->modify('+1 day');
echo $date->format('m-d-Y');

See it in action

Or in PHP 5.4+

echo (DateTime::createFromFormat('m-d-Y', '04-15-2013'))->modify('+1 day')->format('m-d-Y');

reference

Basic example of using .ajax() with JSONP?

There is even easier way how to work with JSONP using jQuery

$.getJSON("http://example.com/something.json?callback=?", function(result){
   //response data are now in the result variable
   alert(result);
});

The ? on the end of the URL tells jQuery that it is a JSONP request instead of JSON. jQuery registers and calls the callback function automatically.

For more detail refer to the jQuery.getJSON documentation.

Write output to a text file in PowerShell

Use the Out-File cmdlet

 Compare-Object ... | Out-File C:\filename.txt

Optionally, add -Encoding utf8 to Out-File as the default encoding is not really ideal for many uses.

How can I align the columns of tables in Bash?

Not sure where you were running this, but the code you posted would not produce the output you gave, at least not in the bash that I'm familiar with.

Try this instead:

stringarray=('test' 'some thing' 'very long long long string' 'blah')
numberarray=(1 22 7777 8888888888)
anotherfieldarray=('other' 'mixed' 456 'data')
array_size=4

for((i=0;i<array_size;i++))
do
    echo ${stringarray[$i]} $'\x1d' ${numberarray[$i]} $'\x1d' ${anotherfieldarray[$i]}
done | column -t -s$'\x1d'

Note that I'm using the group seperator character (1d) intead of tab, because if you are getting these arrays from a file, they might contain tabs.

LINQ to SQL using GROUP BY and COUNT(DISTINCT)

I wouldn't bother doing it in Linq2SQL. Create a stored Procedure for the query you want and understand and then create the object to the stored procedure in the framework or just connect direct to it.

create table with sequence.nextval in oracle

Oracle 12c

We now finally have IDENTITY columns like many other databases, in case of which a sequence is auto-generated behind the scenes. This solution is much faster than a trigger-based one as can be seen in this blog post.

So, your table creation would look like this:

CREATE TABLE qname
(
    qname_id integer GENERATED BY DEFAULT AS IDENTITY (START WITH 1) NOT NULL PRIMARY KEY,
    qname    VARCHAR2(4000) NOT NULL -- CONSTRAINT qname_uk UNIQUE
);

Oracle 11g and below

According to the documentation, you cannot do that:

Restriction on Default Column Values A DEFAULT expression cannot contain references to PL/SQL functions or to other columns, the pseudocolumns CURRVAL, NEXTVAL, LEVEL, PRIOR, and ROWNUM, or date constants that are not fully specified.

The standard way to have "auto increment" columns in Oracle is to use triggers, e.g.

CREATE OR REPLACE TRIGGER my_trigger
  BEFORE INSERT 
  ON qname
  FOR EACH ROW
  -- Optionally restrict this trigger to fire only when really needed
  WHEN (new.qname_id is null)
DECLARE
  v_id qname.qname_id%TYPE;
BEGIN
  -- Select a new value from the sequence into a local variable. As David
  -- commented, this step is optional. You can directly select into :new.qname_id
  SELECT qname_id_seq.nextval INTO v_id FROM DUAL;

  -- :new references the record that you are about to insert into qname. Hence,
  -- you can overwrite the value of :new.qname_id (qname.qname_id) with the value
  -- obtained from your sequence, before inserting
  :new.qname_id := v_id;
END my_trigger;

Read more about Oracle TRIGGERs in the documentation

How can I make Bootstrap 4 columns all the same height?

You just have to use class="row-eq-height" with your class="row" to get equal height columns for previous bootstrap versions.

but with bootstrap 4 this comes natively.

check this link --http://getbootstrap.com.vn/examples/equal-height-columns/

If '<selector>' is an Angular component, then verify that it is part of this module

In my case I had a component in a Shared module.

The component was loading and worked well but typescript was highlighting the html tag with red line and showed this error message.

Inside this component, I noticed I didn't import a rxjs operator.

import {map} from 'rxjs/operators';

When I added this import the error message disappeared.

Check all imports inside the component.

Hope it helps someone.

jQuery map vs. each

1: The arguments to the callback functions are reversed.

.each()'s, $.each()'s, and .map()'s callback function take the index first, and then the element

function (index, element) 

$.map()'s callback has the same arguments, but reversed

function (element, index)

2: .each(), $.each(), and .map() do something special with this

each() calls the function in such a way that this points to the current element. In most cases, you don't even need the two arguments in the callback function.

function shout() { alert(this + '!') }

result = $.each(['lions', 'tigers', 'bears'], shout)

// result == ['lions', 'tigers', 'bears']

For $.map() the this variable refers to the global window object.

3: map() does something special with the callback's return value

map() calls the function on each element, and stores the result in a new array, which it returns. You usually only need to use the first argument in the callback function.

function shout(el) { return el + '!' }

result = $.map(['lions', 'tigers', 'bears'], shout)

// result == ['lions!', 'tigers!', 'bears!']

How can I trigger a JavaScript event click

I'm quite ashamed that there are so many incorrect or undisclosed partial applicability.

The easiest way to do this is through Chrome or Opera (my examples will use Chrome) using the Console. Enter the following code into the console (generally in 1 line):

var l = document.getElementById('testLink');
for(var i=0; i<5; i++){
  l.click();
}

This will generate the required result

Adding and removing extensionattribute to AD object

Extension attributes are added by Exchange. According to this Technet article something like this should work:

Set-Mailbox -Identity "anyUser" -ExtensionCustomAttribute4 @{Remove="myString"}

python, sort descending dataframe with pandas

New syntax (either):

 test = df.sort_values(['one'], ascending=[False])
 test = df.sort_values(['one'], ascending=[0])

Multiline TextBox multiple newline

You need to set the textbox to be multiline, this can be done two ways:

In the control:

<asp:TextBox runat="server" ID="MyBox" TextMode="MultiLine" Rows="10" />

Code Behind:

MyBox.TextMode = TextBoxMode.MultiLine;
MyBox.Rows = 10;

This will render as a <textarea>

How to display both icon and title of action inside ActionBar?

Try adding a TextView to the menubar first and using setCompoundDrawables() to place the image on whichever side you want. Bond click activity to the textview in the end.

MenuItem item = menu.add(Menu.NONE, R.id.menu_item_save, 10, R.string.save);
item.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS|MenuItem.SHOW_AS_ACTION_WITH_TEXT);
TextView textBtn = getTextButton(btn_title, btn_image);
item.setActionView(textBtn);
textBtn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
           // your selector here   }
    });

You can literally customize everything here:

public TextView getTextButton (String btn_title, Drawable btn_image) {
    TextView textBtn = new TextView(this);
    textBtn.setText(btn_title);
    textBtn.setTextColor(Color.WHITE);
    textBtn.setTextSize(18);
    textBtn.setTypeface(Typeface.create("sans-serif-light", Typeface.BOLD));
    textBtn.setGravity(Gravity.CENTER_VERTICAL | Gravity.CENTER_HORIZONTAL);
    Drawable img = btn_image;
    img.setBounds(0, 0, 30, 30);
    textBtn.setCompoundDrawables(null, null, img, null); 
    // left,top,right,bottom. In this case icon is right to the text

    return textBtn;
}

How do I convert a dictionary to a JSON String in C#?

Serializing data structures containing only numeric or boolean values is fairly straightforward. If you don't have much to serialize, you can write a method for your specific type.

For a Dictionary<int, List<int>> as you have specified, you can use Linq:

string MyDictionaryToJson(Dictionary<int, List<int>> dict)
{
    var entries = dict.Select(d =>
        string.Format("\"{0}\": [{1}]", d.Key, string.Join(",", d.Value)));
    return "{" + string.Join(",", entries) + "}";
}

But, if you are serializing several different classes, or more complex data structures, or especially if your data contains string values, you would be better off using a reputable JSON library that already knows how to handle things like escape characters and line breaks. Json.NET is a popular option.

How do you dynamically allocate a matrix?

A matrix is actually an array of arrays.

int rows = ..., cols = ...;
int** matrix = new int*[rows];
for (int i = 0; i < rows; ++i)
    matrix[i] = new int[cols];

Of course, to delete the matrix, you should do the following:

for (int i = 0; i < rows; ++i)
    delete [] matrix[i];
delete [] matrix;

I have just figured out another possibility:

int rows = ..., cols = ...;
int** matrix = new int*[rows];
if (rows)
{
    matrix[0] = new int[rows * cols];
    for (int i = 1; i < rows; ++i)
        matrix[i] = matrix[0] + i * cols;
}

Freeing this array is easier:

if (rows) delete [] matrix[0];
delete [] matrix;

This solution has the advantage of allocating a single big block of memory for all the elements, instead of several little chunks. The first solution I posted is a better example of the arrays of arrays concept, though.

C# 4.0: Convert pdf to byte[] and vice versa

// loading bytes from a file is very easy in C#. The built in System.IO.File.ReadAll* methods take care of making sure every byte is read properly.
// note that for Linux, you will not need the c: part
// just swap out the example folder here with your actual full file path
string pdfFilePath = "c:/pdfdocuments/myfile.pdf";
byte[] bytes = System.IO.File.ReadAllBytes(pdfFilePath);

// munge bytes with whatever pdf software you want, i.e. http://sourceforge.net/projects/itextsharp/
// bytes = MungePdfBytes(bytes); // MungePdfBytes is your custom method to change the PDF data
// ...
// make sure to cleanup after yourself

// and save back - System.IO.File.WriteAll* makes sure all bytes are written properly - this will overwrite the file, if you don't want that, change the path here to something else
System.IO.File.WriteAllBytes(pdfFilePath, bytes);

Removing a Fragment from the back stack

you show fragment in a container (with id= fragmentcontainer) so you remove fragment with:

 Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.fragmentContainer);
            fragmentTransaction.remove(fragment);
            fragmentTransaction.addToBackStack(null);
            fragmentTransaction.commit();

Using json_encode on objects in PHP (regardless of scope)

Following code worked for me:

public function jsonSerialize()
{
    return get_object_vars($this);
}

Excel: last character/string match in a string

I think I get what you mean. Let's say for example you want the right-most \ in the following string (which is stored in cell A1):

Drive:\Folder\SubFolder\Filename.ext

To get the position of the last \, you would use this formula:

=FIND("@",SUBSTITUTE(A1,"\","@",(LEN(A1)-LEN(SUBSTITUTE(A1,"\","")))/LEN("\")))

That tells us the right-most \ is at character 24. It does this by looking for "@" and substituting the very last "\" with an "@". It determines the last one by using

(len(string)-len(substitute(string, substring, "")))\len(substring)

In this scenario, the substring is simply "\" which has a length of 1, so you could leave off the division at the end and just use:

=FIND("@",SUBSTITUTE(A1,"\","@",LEN(A1)-LEN(SUBSTITUTE(A1,"\",""))))

Now we can use that to get the folder path:

=LEFT(A1,FIND("@",SUBSTITUTE(A1,"\","@",LEN(A1)-LEN(SUBSTITUTE(A1,"\","")))))

Here's the folder path without the trailing \

=LEFT(A1,FIND("@",SUBSTITUTE(A1,"\","@",LEN(A1)-LEN(SUBSTITUTE(A1,"\",""))))-1)

And to get just the filename:

=MID(A1,FIND("@",SUBSTITUTE(A1,"\","@",LEN(A1)-LEN(SUBSTITUTE(A1,"\",""))))+1,LEN(A1))

However, here is an alternate version of getting everything to the right of the last instance of a specific character. So using our same example, this would also return the file name:

=TRIM(RIGHT(SUBSTITUTE(A1,"\",REPT(" ",LEN(A1))),LEN(A1)))

Conditionally hide CommandField or ButtonField in Gridview

To conditionally control view of Template/Command fields, use RowDataBound event of Gridview, like:

    <asp:GridView ID="gv1" OnRowDataBound="gv1_RowDataBound"
              runat="server" AutoGenerateColumns="False" DataKeyNames="Id" >
    <Columns>   
        ...        
           <asp:TemplateField HeaderText="Order Status" 
HeaderStyle-HorizontalAlign="Center" ItemStyle-HorizontalAlign="Center"> 
                 <ItemTemplate> 
                       <asp:Label ID="lblOrderStatus" runat="server"
Text='<%# Bind("OrderStatus") %>'></asp:Label> 
                 </ItemTemplate>
                 <HeaderStyle HorizontalAlign="Center"></HeaderStyle>
                 <ItemStyle HorizontalAlign="Center"></ItemStyle>
           </asp:TemplateField>  
        ...

            <asp:CommandField ShowSelectButton="True" SelectText="Select" />

    </Columns>
                </asp:GridView>

and following:

protected void gv1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        Label lblOrderStatus=(Label) e.Row.Cells[4].FindControl("lblOrderStatus");

        if (lblOrderStatus.Text== "Ordered")
        {
            lblOrderStatus.ForeColor = System.Drawing.Color.DarkBlue;
            LinkButton bt = (LinkButton)e.Row.Cells[5].Controls[0];
            bt.Visible = false;
            e.Row.BackColor = System.Drawing.Color.LightGray;
        }
    }

Normalize data in pandas

You can use apply for this, and it's a bit neater:

import numpy as np
import pandas as pd

np.random.seed(1)

df = pd.DataFrame(np.random.randn(4,4)* 4 + 3)

          0         1         2         3
0  9.497381  0.552974  0.887313 -1.291874
1  6.461631 -6.206155  9.979247 -0.044828
2  4.276156  2.002518  8.848432 -5.240563
3  1.710331  1.463783  7.535078 -1.399565

df.apply(lambda x: (x - np.mean(x)) / (np.max(x) - np.min(x)))

          0         1         2         3
0  0.515087  0.133967 -0.651699  0.135175
1  0.125241 -0.689446  0.348301  0.375188
2 -0.155414  0.310554  0.223925 -0.624812
3 -0.484913  0.244924  0.079473  0.114448

Also, it works nicely with groupby, if you select the relevant columns:

df['grp'] = ['A', 'A', 'B', 'B']

          0         1         2         3 grp
0  9.497381  0.552974  0.887313 -1.291874   A
1  6.461631 -6.206155  9.979247 -0.044828   A
2  4.276156  2.002518  8.848432 -5.240563   B
3  1.710331  1.463783  7.535078 -1.399565   B


df.groupby(['grp'])[[0,1,2,3]].apply(lambda x: (x - np.mean(x)) / (np.max(x) - np.min(x)))

     0    1    2    3
0  0.5  0.5 -0.5 -0.5
1 -0.5 -0.5  0.5  0.5
2  0.5  0.5  0.5 -0.5
3 -0.5 -0.5 -0.5  0.5

jQueryUI modal dialog does not show close button (x)

Just linking the CSS worked for me. It may have been missing from my project entirely:

<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">

How to use double or single brackets, parentheses, curly braces

Parentheses in function definition

Parentheses () are being used in function definition:

function_name () { command1 ; command2 ; }

That is the reason you have to escape parentheses even in command parameters:

$ echo (
bash: syntax error near unexpected token `newline'

$ echo \(
(

$ echo () { command echo The command echo was redefined. ; }
$ echo anything
The command echo was redefined.

How to stop event bubbling on checkbox click

As others have mentioned, try stopPropagation().

And there is a second handler to try: event.cancelBubble = true; It's a IE specific handler, but it is supported in at least FF. Don't really know much about it, as I haven't used it myself, but it might be worth a shot, if all else fails.

SQL Server copy all rows from one table into another i.e duplicate table

Duplicate your table into a table to be archived:

SELECT * INTO ArchiveTable FROM MyTable

Delete all entries in your table:

DELETE * FROM MyTable

Docker can't connect to docker daemon

Check if you are using Docker Machine :)

Run docker-machine env default should do the trick.

Because according to documentation:

Docker Machine is a tool that lets you install Docker Engine on virtual hosts, and manage the hosts with docker-machine commands. You can use Machine to create Docker hosts on your local Mac or Windows box, on your company network, in your data center, or on cloud providers like AWS or Digital Ocean.

Using docker-machine commands, you can start, inspect, stop, and restart a managed host, upgrade the Docker client and daemon, and configure a Docker client to talk to your host.

Point the Machine CLI at a running, managed host, and you can run docker commands directly on that host. For example, run docker-machine env default to point to a host called default, follow on-screen instructions to complete env setup, and run docker ps, docker run hello-world, and so forth.

https://docs.docker.com/machine/overview/

Remove last character from C++ string

That's all you need:

#include <string>  //string::pop_back & string::empty

if (!st.empty())
    st.pop_back();

How to change XAMPP apache server port?

To answer the original question:

To change the XAMPP Apache server port here the procedure :

1. Choose a free port number

The default port used by Apache is 80.

Take a look to all your used ports with Netstat (integrated to XAMPP Control Panel).

Screenshot of xampp control netstat

Then you can see all used ports and here we see that the 80port is already used by System.

screenshot netstat port 80

Choose a free port number (8012, for this exemple).

2. Edit the file "httpd.conf"

This file should be found in C:\xampp\apache\conf on Windows or in bin/apache for Linux.:

Listen 80
ServerName localhost:80

Replace them by:

Listen 8012
ServerName localhost:8012

Save the file.

Access to : http://localhost:8012 for check if it's work.

If not, you must to edit the http-ssl.conf file as explain in step 3 below. ?

3. Edit the file "http-ssl.conf"

This file should be found in C:\xampp\apache\conf\extra on Windows or see this link for Linux.

Locate the following lines:

Listen 443
<VirtualHost _default_:443>
ServerName localhost:443

Replace them by with a other port number (8013 for this example) :

Listen 8013
<VirtualHost _default_:8013>
ServerName localhost:8013

Save the file.

Restart the Apache Server.

Access to : http://localhost:8012 for check if it's work.

4. Configure XAMPP Apache server settings

If your want to access localhost without specify the port number in the URL
http://localhost instead of http://localhost:8012.

  • Open Xampp Control Panel
  • Go to Config ? Service and Port Settings ? Apache
  • Replace the Main Port and SSL Port values ??with those chosen (e.g. 8012 and 8013).
  • Save Service settings
  • Save Configuration of Control Panel
  • Restart the Apache Server xampp apache setting port It should work now.

4.1. Web browser configuration

If this configuration isn't hiding port number in URL it's because your web browser is not configured for. See : Tools ? Options ? General ? Connection Settings... will allow you to choose different ports or change proxy settings.

4.2. For the rare cases of ultimate bad luck

If step 4 and Web browser configuration are not working for you the only way to do this is to change back to 80, or to install a listener on port 80 (like a proxy) that redirects all your traffic to port 8012.

To answer your problem :

If you still have this message in Control Panel Console :

Apache Started [Port 80]

  • Find location of xampp-control.exe file (probably in C:\xampp)
  • Create a file XAMPP.INI in that directory (so XAMPP.ini and xampp-control.exe are in the same directory)

Put following lines in the XAMPP.INI file:

[PORTS]
apache = 8012

Now , you will always get:

Apache started [Port 8012]

Please note that, this is for display purpose only. It has no relation with your httpd.conf.

How can I pass a parameter to a Java Thread?

Either write a class that implements Runnable, and pass whatever you need in a suitably defined constructor, or write a class that extends Thread with a suitably defined constructor that calls super() with appropriate parameters.

How to access a RowDataPacket object

Hi try this 100% works:

results=JSON.parse(JSON.stringify(results))
doStuffwithTheResult(results); 

Regex select all text between tags

For multiple lines:

<htmltag>(.+)((\s)+(.+))+</htmltag>

How to add DOM element script to head section?

For modern browsers, the best solution is to use Promises.

Go to https://stackoverflow.com/a/63936671/13720928 to find out more!

Drawing Isometric game worlds

Update: Corrected map rendering algorithm, added more illustrations, changed formating.

Perhaps the advantage for the "zig-zag" technique for mapping the tiles to the screen can be said that the tile's x and y coordinates are on the vertical and horizontal axes.

"Drawing in a diamond" approach:

By drawing an isometric map using "drawing in a diamond", which I believe refers to just rendering the map by using a nested for-loop over the two-dimensional array, such as this example:

tile_map[][] = [[...],...]

for (cellY = 0; cellY < tile_map.size; cellY++):
    for (cellX = 0; cellX < tile_map[cellY].size cellX++):
        draw(
            tile_map[cellX][cellY],
            screenX = (cellX * tile_width  / 2) + (cellY * tile_width  / 2)
            screenY = (cellY * tile_height / 2) - (cellX * tile_height / 2)
        )

Advantage:

The advantage to the approach is that it is a simple nested for-loop with fairly straight forward logic that works consistently throughout all tiles.

Disadvantage:

One downside to that approach is that the x and y coordinates of the tiles on the map will increase in diagonal lines, which might make it more difficult to visually map the location on the screen to the map represented as an array:

Image of tile map

However, there is going to be a pitfall to implementing the above example code -- the rendering order will cause tiles that are supposed to be behind certain tiles to be drawn on top of the tiles in front:

Resulting image from incorrect rendering order

In order to amend this problem, the inner for-loop's order must be reversed -- starting from the highest value, and rendering toward the lower value:

tile_map[][] = [[...],...]

for (i = 0; i < tile_map.size; i++):
    for (j = tile_map[i].size; j >= 0; j--):  // Changed loop condition here.
        draw(
            tile_map[i][j],
            x = (j * tile_width / 2) + (i * tile_width / 2)
            y = (i * tile_height / 2) - (j * tile_height / 2)
        )

With the above fix, the rendering of the map should be corrected:

Resulting image from correct rendering order

"Zig-zag" approach:

Advantage:

Perhaps the advantage of the "zig-zag" approach is that the rendered map may appear to be a little more vertically compact than the "diamond" approach:

Zig-zag approach to rendering seems compact

Disadvantage:

From trying to implement the zig-zag technique, the disadvantage may be that it is a little bit harder to write the rendering code because it cannot be written as simple as a nested for-loop over each element in an array:

tile_map[][] = [[...],...]

for (i = 0; i < tile_map.size; i++):
    if i is odd:
        offset_x = tile_width / 2
    else:
        offset_x = 0

    for (j = 0; j < tile_map[i].size; j++):
        draw(
            tile_map[i][j],
            x = (j * tile_width) + offset_x,
            y = i * tile_height / 2
        )

Also, it may be a little bit difficult to try to figure out the coordinate of a tile due to the staggered nature of the rendering order:

Coordinates on a zig-zag order rendering

Note: The illustrations included in this answer were created with a Java implementation of the tile rendering code presented, with the following int array as the map:

tileMap = new int[][] {
    {0, 1, 2, 3},
    {3, 2, 1, 0},
    {0, 0, 1, 1},
    {2, 2, 3, 3}
};

The tile images are:

  • tileImage[0] -> A box with a box inside.
  • tileImage[1] -> A black box.
  • tileImage[2] -> A white box.
  • tileImage[3] -> A box with a tall gray object in it.

A Note on Tile Widths and Heights

The variables tile_width and tile_height which are used in the above code examples refer to the width and height of the ground tile in the image representing the tile:

Image showing the tile width and height

Using the dimensions of the image will work, as long as the image dimensions and the tile dimensions match. Otherwise, the tile map could be rendered with gaps between the tiles.

No serializer found for class org.hibernate.proxy.pojo.javassist.Javassist?

As it is correctly suggested in previous answers, lazy loading means that when you fetch your object from the database, the nested objects are not fetched (and may be fetched later when required).

Now Jackson tries to serialize the nested object (== make JSON out of it), but fails as it finds JavassistLazyInitializer instead of normal object. This is the error you see. Now, how to solve it?

As suggested by CP510 previously, one option is to suppress the error by this line of configuration:

spring.jackson.serialization.fail-on-empty-beans=false

But this is dealing with the symptoms, not the cause. To solve it elegantly, you need to decide whether you need this object in JSON or not?

  1. Should you need the object in JSON, remove the FetchType.LAZY option from the field that causes it (it might also be a field in some nested object, not only in the root entity you are fetching).

  2. If do not need the object in JSON, annotate the getter of this field (or the field itself, if you do not need to accept incoming values either) with @JsonIgnore, for example:

    // this field will not be serialized to/from JSON @JsonIgnore private NestedType secret;

Should you have more complex needs (e.g. different rules for different REST controllers using the same entity), you can use jackson views or filtering or for very simple use case, fetch nested objects separately.

Create dynamic variable name

Variable names should be known at compile time. If you intend to populate those names dynamically at runtime you could use a List<T>

 var variables = List<Variable>();
 variables.Add(new Variable { Name = inputStr1 });
 variables.Add(new Variable { Name = inputStr2 });

here input string maybe any text or any list

Open Url in default web browser

Try this:

import React, { useCallback } from "react";
import { Linking } from "react-native";
OpenWEB = () => {
  Linking.openURL(url);
};

const App = () => {
  return <View onPress={() => OpenWeb}>OPEN YOUR WEB</View>;
};

Hope this will solve your problem.

S3 limit to objects in a bucket

It looks like the limit has changed. You can store 5TB for a single object.

The total volume of data and number of objects you can store are unlimited. Individual Amazon S3 objects can range in size from a minimum of 0 bytes to a maximum of 5 terabytes. The largest object that can be uploaded in a single PUT is 5 gigabytes. For objects larger than 100 megabytes, customers should consider using the Multipart Upload capability.

http://aws.amazon.com/s3/faqs/#How_much_data_can_I_store

Required maven dependencies for Apache POI to work

Add this dependency to work with Apache POI

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.16-beta1</version>
 </dependency>

How to show data in a table by using psql command line interface?

On windows use the name of the table in quotes: TABLE "user"; or SELECT * FROM "user";

How to implement a binary tree?

I know many good solutions have already been posted but I usually have a different approach for binary trees: going with some Node class and implementing it directly is more readable but when you have a lot of nodes it can become very greedy regarding memory, so I suggest adding one layer of complexity and storing the nodes in a python list, and then simulating a tree behavior using only the list.

You can still define a Node class to finally represent the nodes in the tree when needed, but keeping them in a simple form [value, left, right] in a list will use half the memory or less!

Here is a quick example of a Binary Search Tree class storing the nodes in an array. It provides basic fonctions such as add, remove, find...

"""
Basic Binary Search Tree class without recursion...
"""

__author__ = "@fbparis"

class Node(object):
    __slots__ = "value", "parent", "left", "right"
    def __init__(self, value, parent=None, left=None, right=None):
        self.value = value
        self.parent = parent
        self.left = left
        self.right = right

    def __repr__(self):
        return "<%s object at %s: parent=%s, left=%s, right=%s, value=%s>" % (self.__class__.__name__, hex(id(self)), self.parent, self.left, self.right, self.value)

class BinarySearchTree(object):
    __slots__ = "_tree"
    def __init__(self, *args):
        self._tree = []
        if args:
            for x in args[0]:
                self.add(x)

    def __len__(self):
        return len(self._tree)

    def __repr__(self):
        return "<%s object at %s with %d nodes>" % (self.__class__.__name__, hex(id(self)), len(self))

    def __str__(self, nodes=None, level=0):
        ret = ""
        if nodes is None:
            if len(self):
                nodes = [0]
            else:
                nodes = []
        for node in nodes:
            if node is None:
                continue
            ret += "-" * level + " %s\n" % self._tree[node][0]
            ret += self.__str__(self._tree[node][2:4], level + 1)
        if level == 0:
            ret = ret.strip()
        return ret

    def __contains__(self, value):
        if len(self):
            node_index = 0
            while self._tree[node_index][0] != value:
                if value < self._tree[node_index][0]:
                    node_index = self._tree[node_index][2]
                else:
                    node_index = self._tree[node_index][3]
                if node_index is None:
                    return False
            return True
        return False

    def __eq__(self, other):
        return self._tree == other._tree

    def add(self, value):
        if len(self):
            node_index = 0
            while self._tree[node_index][0] != value:
                if value < self._tree[node_index][0]:
                    b = self._tree[node_index][2]
                    k = 2
                else:
                    b = self._tree[node_index][3]
                    k = 3
                if b is None:
                    self._tree[node_index][k] = len(self)
                    self._tree.append([value, node_index, None, None])
                    break
                node_index = b
        else:
            self._tree.append([value, None, None, None])

    def remove(self, value):
        if len(self):
            node_index = 0
            while self._tree[node_index][0] != value:
                if value < self._tree[node_index][0]:
                    node_index = self._tree[node_index][2]
                else:
                    node_index = self._tree[node_index][3]
                if node_index is None:
                    raise KeyError
            if self._tree[node_index][2] is not None:
                b, d = 2, 3
            elif self._tree[node_index][3] is not None:
                b, d = 3, 2
            else:
                i = node_index
                b = None
            if b is not None:
                i = self._tree[node_index][b]
                while self._tree[i][d] is not None:
                    i = self._tree[i][d]
                p = self._tree[i][1]
                b = self._tree[i][b]
                if p == node_index:
                    self._tree[p][5-d] = b
                else:
                    self._tree[p][d] = b
                if b is not None:
                    self._tree[b][1] = p
                self._tree[node_index][0] = self._tree[i][0]
            else:
                p = self._tree[i][1]
                if p is not None:
                    if self._tree[p][2] == i:
                        self._tree[p][2] = None
                    else:
                        self._tree[p][3] = None
            last = self._tree.pop()
            n = len(self)
            if i < n:
                self._tree[i] = last[:]
                if last[2] is not None:
                    self._tree[last[2]][1] = i
                if last[3] is not None:
                    self._tree[last[3]][1] = i
                if self._tree[last[1]][2] == n:
                    self._tree[last[1]][2] = i
                else:
                    self._tree[last[1]][3] = i
        else:
            raise KeyError

    def find(self, value):
        if len(self):
            node_index = 0
            while self._tree[node_index][0] != value:
                if value < self._tree[node_index][0]:
                    node_index = self._tree[node_index][2]
                else:
                    node_index = self._tree[node_index][3]
                if node_index is None:
                    return None
            return Node(*self._tree[node_index])
        return None

I've added a parent attribute so that you can remove any node and maintain the BST structure.

Sorry for the readability, especially for the "remove" function. Basically, when a node is removed, we pop the tree array and replace it with the last element (except if we wanted to remove the last node). To maintain the BST structure, the removed node is replaced with the max of its left children or the min of its right children and some operations have to be done in order to keep the indexes valid but it's fast enough.

I used this technique for more advanced stuff to build some big words dictionaries with an internal radix trie and I was able to divide memory consumption by 7-8 (you can see an example here: https://gist.github.com/fbparis/b3ddd5673b603b42c880974b23db7cda)

How do I decrease the size of my sql server log file?

I had the same problem, my database log file size was about 39 gigabyte, and after shrinking (both database and files) it reduced to 37 gigabyte that was not enough, so I did this solution: (I did not need the ldf file (log file) anymore)

(**Important) : Get a full backup of your database before the process.

  1. Run "checkpoint" on that database.

  2. Detach that database (right click on the database and chose tasks >> Detach...) {if you see an error, do the steps in the end of this text}

  3. Move MyDatabase.ldf to another folder, you can find it in your hard disk in the same folder as your database (Just in case you need it in the future for some reason such as what user did some task).

  4. Attach the database (right click on Databases and chose Attach...)

  5. On attach dialog remove the .ldf file (which shows 'file not found' comment) and click Ok. (don`t worry the ldf file will be created after the attachment process.)

  6. After that, a new log file create with a size of 504 KB!!!.

In step 2, if you faced an error that database is used by another user, you can:

1.run this command on master database "sp_who2" and see what process using your database.

2.read the process number, for example it is 52 and type "kill 52", now your database is free and ready to detach.

If the number of processes using your database is too much:

1.Open services (type services in windows start) find SQL Server ... process and reset it (right click and chose reset).

  1. Immediately click Ok button in the detach dialog box (that showed the detach error previously).

How can I get around MySQL Errcode 13 with SELECT INTO OUTFILE?

Which particular version of Ubuntu is this and is this Ubuntu Server Edition?

Recent Ubuntu Server Editions (such as 10.04) ship with AppArmor and MySQL's profile might be in enforcing mode by default. You can check this by executing sudo aa-status like so:

# sudo aa-status
5 profiles are loaded.
5 profiles are in enforce mode.
   /usr/lib/connman/scripts/dhclient-script
   /sbin/dhclient3
   /usr/sbin/tcpdump
   /usr/lib/NetworkManager/nm-dhcp-client.action
   /usr/sbin/mysqld
0 profiles are in complain mode.
1 processes have profiles defined.
1 processes are in enforce mode :
   /usr/sbin/mysqld (1089)
0 processes are in complain mode.

If mysqld is included in enforce mode, then it is the one probably denying the write. Entries would also be written in /var/log/messages when AppArmor blocks the writes/accesses. What you can do is edit /etc/apparmor.d/usr.sbin.mysqld and add /data/ and /data/* near the bottom like so:

...  
/usr/sbin/mysqld  {  
    ...  
    /var/log/mysql/ r,  
    /var/log/mysql/* rw,  
    /var/run/mysqld/mysqld.pid w,  
    /var/run/mysqld/mysqld.sock w,  
    **/data/ r,  
    /data/* rw,**  
}

And then make AppArmor reload the profiles.

# sudo /etc/init.d/apparmor reload

WARNING: the change above will allow MySQL to read and write to the /data directory. We hope you've already considered the security implications of this.

how to convert String into Date time format in JAVA?

With SimpleDateFormat. And steps are -

  1. Create your date pattern string
  2. Create SimpleDateFormat Object
  3. And parse with it.
  4. It will return Date Object.

Subset data to contain only columns whose names match a condition

Just in case for data.table users, the following works for me:

df[, grep("ABC", names(df)), with = FALSE]

ES6 export default with multiple functions referring to each other

tl;dr: baz() { this.foo(); this.bar() }

In ES2015 this construct:

var obj = {
    foo() { console.log('foo') }
}

is equal to this ES5 code:

var obj = {
    foo : function foo() { console.log('foo') }
}

exports.default = {} is like creating an object, your default export translates to ES5 code like this:

exports['default'] = {
    foo: function foo() {
        console.log('foo');
    },
    bar: function bar() {
        console.log('bar');
    },
    baz: function baz() {
        foo();bar();
    }
};

now it's kind of obvious (I hope) that baz tries to call foo and bar defined somewhere in the outer scope, which are undefined. But this.foo and this.bar will resolve to the keys defined in exports['default'] object. So the default export referencing its own methods shold look like this:

export default {
    foo() { console.log('foo') }, 
    bar() { console.log('bar') },
    baz() { this.foo(); this.bar() }
}

See babel repl transpiled code.

Java: Static Class?

comment on the "private constructor" arguments: come on, developers are not that stupid; but they ARE lazy. creating an object then call static methods? not gonna happen.

don't spend too much time to make sure your class cannot be misused. have some faith for your colleagues. and there is always a way to misuse your class no matter how you protect it. the only thing that cannot be misused is a thing that is completely useless.

Undefined reference to main - collect2: ld returned 1 exit status

One possibility which has not been mentioned so far is that you might not be editing the file you think you are. i.e. your editor might have a different cwd than you had in mind.

Run 'more' on the file you're compiling to double check that it does indeed have the contents you hope it does. Hope that helps!

How to determine CPU and memory consumption from inside a process?

Mac OS X

I was hoping to find similar information for Mac OS X as well. Since it wasn't here, I went out and dug it up myself. Here are some of the things I found. If anyone has any other suggestions, I'd love to hear them.

Total Virtual Memory

This one is tricky on Mac OS X because it doesn't use a preset swap partition or file like Linux. Here's an entry from Apple's documentation:

Note: Unlike most Unix-based operating systems, Mac OS X does not use a preallocated swap partition for virtual memory. Instead, it uses all of the available space on the machine’s boot partition.

So, if you want to know how much virtual memory is still available, you need to get the size of the root partition. You can do that like this:

struct statfs stats;
if (0 == statfs("/", &stats))
{
    myFreeSwap = (uint64_t)stats.f_bsize * stats.f_bfree;
}

Total Virtual Currently Used

Calling systcl with the "vm.swapusage" key provides interesting information about swap usage:

sysctl -n vm.swapusage
vm.swapusage: total = 3072.00M  used = 2511.78M  free = 560.22M  (encrypted)

Not that the total swap usage displayed here can change if more swap is needed as explained in the section above. So the total is actually the current swap total. In C++, this data can be queried this way:

xsw_usage vmusage = {0};
size_t size = sizeof(vmusage);
if( sysctlbyname("vm.swapusage", &vmusage, &size, NULL, 0)!=0 )
{
   perror( "unable to get swap usage by calling sysctlbyname(\"vm.swapusage\",...)" );
}

Note that the "xsw_usage", declared in sysctl.h, seems not documented and I suspect there there is a more portable way of accessing these values.

Virtual Memory Currently Used by my Process

You can get statistics about your current process using the task_info function. That includes the current resident size of your process and the current virtual size.

#include<mach/mach.h>

struct task_basic_info t_info;
mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;

if (KERN_SUCCESS != task_info(mach_task_self(),
                              TASK_BASIC_INFO, (task_info_t)&t_info, 
                              &t_info_count))
{
    return -1;
}
// resident size is in t_info.resident_size;
// virtual size is in t_info.virtual_size;

Total RAM available

The amount of physical RAM available in your system is available using the sysctl system function like this:

#include <sys/types.h>
#include <sys/sysctl.h>
...
int mib[2];
int64_t physical_memory;
mib[0] = CTL_HW;
mib[1] = HW_MEMSIZE;
length = sizeof(int64_t);
sysctl(mib, 2, &physical_memory, &length, NULL, 0);

RAM Currently Used

You can get general memory statistics from the host_statistics system function.

#include <mach/vm_statistics.h>
#include <mach/mach_types.h>
#include <mach/mach_init.h>
#include <mach/mach_host.h>

int main(int argc, const char * argv[]) {
    vm_size_t page_size;
    mach_port_t mach_port;
    mach_msg_type_number_t count;
    vm_statistics64_data_t vm_stats;

    mach_port = mach_host_self();
    count = sizeof(vm_stats) / sizeof(natural_t);
    if (KERN_SUCCESS == host_page_size(mach_port, &page_size) &&
        KERN_SUCCESS == host_statistics64(mach_port, HOST_VM_INFO,
                                        (host_info64_t)&vm_stats, &count))
    {
        long long free_memory = (int64_t)vm_stats.free_count * (int64_t)page_size;

        long long used_memory = ((int64_t)vm_stats.active_count +
                                 (int64_t)vm_stats.inactive_count +
                                 (int64_t)vm_stats.wire_count) *  (int64_t)page_size;
        printf("free memory: %lld\nused memory: %lld\n", free_memory, used_memory);
    }

    return 0;
}

One thing to note here are that there are five types of memory pages in Mac OS X. They are as follows:

  1. Wired pages that are locked in place and cannot be swapped out
  2. Active pages that are loading into physical memory and would be relatively difficult to swap out
  3. Inactive pages that are loaded into memory, but haven't been used recently and may not even be needed at all. These are potential candidates for swapping. This memory would probably need to be flushed.
  4. Cached pages that have been some how cached that are likely to be easily reused. Cached memory probably would not require flushing. It is still possible for cached pages to be reactivated
  5. Free pages that are completely free and ready to be used.

It is good to note that just because Mac OS X may show very little actual free memory at times that it may not be a good indication of how much is ready to be used on short notice.

RAM Currently Used by my Process

See the "Virtual Memory Currently Used by my Process" above. The same code applies.

Sorted collection in Java

You want the SortedSet implementations, namely TreeSet.

How to find Max Date in List<Object>?

A small improvement from the accepted answer is to do the null check and also get full object.

public class DateComparator {

public static void main(String[] args) throws ParseException {
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");

    List<Employee> employees = new ArrayList<>();
    employees.add(new Employee(1, "name1", addDays(new Date(), 1)));
    employees.add(new Employee(2, "name2", addDays(new Date(), 3)));
    employees.add(new Employee(3, "name3", addDays(new Date(), 6)));
    employees.add(new Employee(4, "name4", null));
    employees.add(new Employee(5, "name5", addDays(new Date(), 4)));
    employees.add(new Employee(6, "name6", addDays(new Date(), 5)));
    System.out.println(employees);
    Date maxDate = employees.stream().filter(emp -> emp.getJoiningDate() != null).map(Employee::getJoiningDate).max(Date::compareTo).get();
    System.out.println(format.format(maxDate));
    //Comparator<Employee> comparator = (p1, p2) -> p1.getJoiningDate().compareTo(p2.getJoiningDate());
    Comparator<Employee> comparator = Comparator.comparing(Employee::getJoiningDate);
    Employee maxDatedEmploye = employees.stream().filter(emp -> emp.getJoiningDate() != null).max(comparator).get();
    System.out.println(" maxDatedEmploye : " + maxDatedEmploye);

    Employee minDatedEmployee = employees.stream().filter(emp -> emp.getJoiningDate() != null).min(comparator).get();
    System.out.println(" minDatedEmployee : " + minDatedEmployee);

}

public static Date addDays(Date date, int days) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.DATE, days); // minus number would decrement the days
    return cal.getTime();
}
}

You would get below results :

 [Employee [empId=1, empName=name1, joiningDate=Wed Mar 21 13:33:09 EDT 2018],
Employee [empId=2, empName=name2, joiningDate=Fri Mar 23 13:33:09 EDT 2018],
Employee [empId=3, empName=name3, joiningDate=Mon Mar 26 13:33:09 EDT 2018],
Employee [empId=4, empName=name4, joiningDate=null],
Employee [empId=5, empName=name5, joiningDate=Sat Mar 24 13:33:09 EDT 2018],
Employee [empId=6, empName=name6, joiningDate=Sun Mar 25 13:33:09 EDT 2018]
]
2018-03-26
 maxDatedEmploye : Employee [empId=3, empName=name3, joiningDate=Mon Mar 26 13:33:09 EDT 2018]

 minDatedEmployee : Employee [empId=1, empName=name1, joiningDate=Wed Mar 21 13:33:09 EDT 2018]

Update : What if list itself is empty ?

        Date maxDate = employees.stream().filter(emp -> emp.getJoiningDate() != null).map(Employee::getJoiningDate).max(Date::compareTo).orElse(new Date());
    System.out.println(format.format(maxDate));
    Comparator<Employee> comparator = Comparator.comparing(Employee::getJoiningDate);
    Employee maxDatedEmploye = employees.stream().filter(emp -> emp.getJoiningDate() != null).max(comparator).orElse(null);
    System.out.println(" maxDatedEmploye : " + maxDatedEmploye);

Writing html form data to a txt file without the use of a webserver

You can use JavaScript:

<script type ="text/javascript">
 function WriteToFile(passForm) {

    set fso = CreateObject("Scripting.FileSystemObject");  
    set s = fso.CreateTextFile("C:\test.txt", True);
    s.writeline(document.passForm.input1.value);
    s.writeline(document.passForm.input2.value);
    s.writeline(document.passForm.input3.value);
    s.Close();
 }
  </script>

If this does not work, an alternative is the ActiveX object:

<script type = "text/javascript">
function WriteToFile(passForm)
{
var fso = new ActiveXObject("Scripting.FileSystemObject");
var s = fso.CreateTextFile("C:\\Test.txt", true);
s.WriteLine(document.passForm.input.value);
s.Close();
}
</script>

Unfortunately, the ActiveX object, to my knowledge, is only supported in IE.

How do I bind a WPF DataGrid to a variable number of columns?

Here's a workaround for Binding Columns in the DataGrid. Since the Columns property is ReadOnly, like everyone noticed, I made an Attached Property called BindableColumns which updates the Columns in the DataGrid everytime the collection changes through the CollectionChanged event.

If we have this Collection of DataGridColumn's

public ObservableCollection<DataGridColumn> ColumnCollection
{
    get;
    private set;
}

Then we can bind BindableColumns to the ColumnCollection like this

<DataGrid Name="dataGrid"
          local:DataGridColumnsBehavior.BindableColumns="{Binding ColumnCollection}"
          AutoGenerateColumns="False"
          ...>

The Attached Property BindableColumns

public class DataGridColumnsBehavior
{
    public static readonly DependencyProperty BindableColumnsProperty =
        DependencyProperty.RegisterAttached("BindableColumns",
                                            typeof(ObservableCollection<DataGridColumn>),
                                            typeof(DataGridColumnsBehavior),
                                            new UIPropertyMetadata(null, BindableColumnsPropertyChanged));
    private static void BindableColumnsPropertyChanged(DependencyObject source, DependencyPropertyChangedEventArgs e)
    {
        DataGrid dataGrid = source as DataGrid;
        ObservableCollection<DataGridColumn> columns = e.NewValue as ObservableCollection<DataGridColumn>;
        dataGrid.Columns.Clear();
        if (columns == null)
        {
            return;
        }
        foreach (DataGridColumn column in columns)
        {
            dataGrid.Columns.Add(column);
        }
        columns.CollectionChanged += (sender, e2) =>
        {
            NotifyCollectionChangedEventArgs ne = e2 as NotifyCollectionChangedEventArgs;
            if (ne.Action == NotifyCollectionChangedAction.Reset)
            {
                dataGrid.Columns.Clear();
                foreach (DataGridColumn column in ne.NewItems)
                {
                    dataGrid.Columns.Add(column);
                }
            }
            else if (ne.Action == NotifyCollectionChangedAction.Add)
            {
                foreach (DataGridColumn column in ne.NewItems)
                {
                    dataGrid.Columns.Add(column);
                }
            }
            else if (ne.Action == NotifyCollectionChangedAction.Move)
            {
                dataGrid.Columns.Move(ne.OldStartingIndex, ne.NewStartingIndex);
            }
            else if (ne.Action == NotifyCollectionChangedAction.Remove)
            {
                foreach (DataGridColumn column in ne.OldItems)
                {
                    dataGrid.Columns.Remove(column);
                }
            }
            else if (ne.Action == NotifyCollectionChangedAction.Replace)
            {
                dataGrid.Columns[ne.NewStartingIndex] = ne.NewItems[0] as DataGridColumn;
            }
        };
    }
    public static void SetBindableColumns(DependencyObject element, ObservableCollection<DataGridColumn> value)
    {
        element.SetValue(BindableColumnsProperty, value);
    }
    public static ObservableCollection<DataGridColumn> GetBindableColumns(DependencyObject element)
    {
        return (ObservableCollection<DataGridColumn>)element.GetValue(BindableColumnsProperty);
    }
}

Style input element to fill remaining width of its container

Please use flexbox for this. You have a container that is going to flex its children into a row. The first child takes its space as needed. The second one flexes to take all the remaining space:

_x000D_
_x000D_
<div style="display:flex;flex-direction:row">_x000D_
    <label for="MyInput">label&nbsp;text</label>_x000D_
    <input type="text" id="MyInput" style="flex:1" />_x000D_
</div>
_x000D_
_x000D_
_x000D_

How can I reorder a list?

This is what I used when I stumbled upon this problem.

def order(list_item, i): # reorder at index i
    order_at = list_item.index(i)
    ordered_list = list_item[order_at:] + list_item[:order_at]
    return ordered_list

EX: for the the lowercase letters

order(string.ascii_lowercase, 'h'):
>>> 'hijklmnopqrstuvwxyzabcdefg'

It simply just shifts the list to a specified index

creating Hashmap from a JSON String

HashMap<String, String> hashMap = new HashMap<String, String>();
String string = "{\"phonetype\":\"N95\",\"cat\":\"WP\"}";

try {
    JSONObject json = new JSONObject(string);

    hashMap.put("phonetype", json.getString("phonetype"));
    hashMap.put("cat", json.getString("cat"));
} catch (JSONException e) {
     // TODO Handle expection!
}

Non-static variable cannot be referenced from a static context

It is ClassLoader responsible to load the class files.Let's see what happens when we write our own classes.

Example 1:

class StaticTest {

      static int a;
      int b;
      int c;
}

Now we can see that class "StaticTest" has 3 fields.But actually there is no existence of b,c member variable.But why ???. OK Lest's see. Here b,c are instance variable.Since instance variable gets the memory at the time of object creation. So here b,c are not getting any memory yet. That's why there is no existence of b,c. So There is only existence of a. For ClassLoader it has only one information about a. ClassLoader yet not recognize b,c because it's object not instantiated yet.

Let's see another example: Example 2:

class StaticTest {

      public void display() {
          System.out.println("Static Test");
      }


      public static void main(String []cmd) {

             display();       
      }

}

Now if we try to compile this code compiler will give CE error. CE: non-static method display() cannot be referenced from a static context.

Now For ClassLoader it looks like:

class StaticTest {

      public static void main(String []cmd) {

             display();       
      }

}

In Example 2 CE error is because we call non static method from a static context. So it is not possible for ClassLoader to recognize method display() at compile time.So compile time error is occurred.

How do I use CSS with a ruby on rails application?

If you are using rails > 3 version, then there is a concept called asset pipeline. You could add your CSS to

app/assets/stylesheets

then it will automatically be picked up by the app. (this is useful as rails will automatically compress the CSS files)

read more here about the asset pipeline

python save image from url

import random
import urllib.request

def download_image(url):
    name = random.randrange(1,100)
    fullname = str(name)+".jpg"
    urllib.request.urlretrieve(url,fullname)     
download_image("http://site.meishij.net/r/58/25/3568808/a3568808_142682562777944.jpg")

Reset par to the default values at startup

From Quick-R

par()              # view current settings
opar <- par()      # make a copy of current settings
par(col.lab="red") # red x and y labels 
hist(mtcars$mpg)   # create a plot with these new settings 
par(opar)          # restore original settings

Is HTML considered a programming language?

No - there's a big prejudice in IT against web design; but in this case the "real" programmers are on pretty firm ground.

If you've done a lot of web design work you've probably done some JavaScript, so you can put that down under 'programming languages'; if you want to list HTML as well, then I agree with the answer that suggests "Technologies".

But unless you're targeting agents who're trying to tick boxes rather than find you a good job, a bare list of things you've used doesn't really look all that good. You're better off listing the projects you've worked on and detailing the technologies you used on each; that demonstrates that you've got real experience of using them rather than just that you know some buzzwords.

How can I pass a parameter in Action?

Dirty trick: You could as well use lambda expression to pass any code you want including the call with parameters.

this.Include(includes, () =>
{
    _context.Cars.Include(<parameters>);
});

TextView bold via xml file?

Use android:textStyle="bold"

4 ways to make Android TextView Bold

like this

<TextView
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:textSize="12dip"
android:textStyle="bold"
/>

There are many ways to make Android TextView bold.

Implement specialization in ER diagram

So I assume your permissions table has a foreign key reference to admin_accounts table. If so because of referential integrity you will only be able to add permissions for account ids exsiting in the admin accounts table. Which also means that you wont be able to enter a user_account_id [assuming there are no duplicates!]

How to create a string with format?

The beauty of String(format:) is that you can save a formatting string and then reuse it later in dozen of places. It also can be localized in this single place. Where as in case of the interpolation approach you must write it again and again.

Div width 100% minus fixed amount of pixels

Maybe I'm being dumb, but isn't table the obvious solution here?

<div class="parent">
    <div class="fixed">
    <div class="stretchToFit">
</div>

.parent{ display: table; width 100%; }
.fixed { display: table-cell; width: 150px; }
.stretchToFit{ display: table-cell; vertical-align: top}

Another way that I've figured out in chrome is even simpler, but man is it a hack!

.fixed{ 
   float: left
}
.stretchToFit{
   display: table-cell;
   width: 1%;
}

This alone should fill the rest of the line horizontally, as table-cells do. However, you get some strange issues with it going over 100% of its parent, setting the width to a percent value fixes it though.

Get everything after and before certain character in SQL Server

SELECT SUBSTRING('[email protected]',1,(CHARINDEX('@','[email protected]')-1)) Before, RIGHT('[email protected]',(CHARINDEX('@','[email protected]')+1)) After

A transport-level error has occurred when receiving results from the server

Try the following command on the command prompt:

netsh interface tcp set global autotuning=disabled

This turns off the auto scaling abilities of the network stack

How to keep form values after post

you can save them into a $_SESSION variable and then when the user calls that page again populate all the inputs with their respective session variables.

How do I turn a String into a InputStreamReader in java?

I also found the apache commons IOUtils class , so :

InputStreamReader isr = new InputStreamReader(IOUtils.toInputStream(myString));

What is a superfast way to read large files line-by-line in VBA?

I would think , in a large file scenario using a stream would be far more efficient, because memory consumption would be very small.

But your algorithm could alternate between using a stream and loading the entire thing in memory based on the file size. I wouldn't be surprised if one is only better than the other under certain criteria.

Read file line by line in PowerShell

I was able to read a 4GB log file in about 50 seconds with the following. You may be able to make it faster by loading it as a C# assembly dynamically using PowerShell.

[System.IO.StreamReader]$sr = [System.IO.File]::Open($file, [System.IO.FileMode]::Open)
while (-not $sr.EndOfStream){
    $line = $sr.ReadLine()
}
$sr.Close() 

How can I convert a string to boolean in JavaScript?

If you are certain that the test subject is always a string, then explicitly checking that it equals true is your best bet.

You may want to consider including an extra bit of code just in case the subject could actually a boolean.

var isTrueSet =
    myValue === true ||
    myValue != null &&
    myValue.toString().toLowerCase() === 'true';

This could save you a bit of work in the future if the code gets improved/refactored to use actual boolean values instead of strings.

JUnit Testing Exceptions

are you sure you told it to expect the exception?

for newer junit (>= 4.7), you can use something like (from here)

@Rule
public ExpectedException exception = ExpectedException.none();

@Test
public void testRodneCisloRok(){
    exception.expect(IllegalArgumentException.class);
    exception.expectMessage("error1");
    new RodneCislo("891415",dopocitej("891415"));
}

and for older junit, this:

@Test(expected = ArithmeticException.class)  
public void divisionWithException() {  
  int i = 1/0;
}

PHP Fatal error: Call to undefined function mssql_connect()

I am using IIS and mysql (directly downloaded, without wamp or xampp) My php was installed in c:\php I was getting the error of "call to undefined function mysql_connect()" For me the change of extension_dir worked. This is what I did. In the php.ini, Originally, I had this line

; On windows: extension_dir = "ext"

I changed it to:

; On windows: extension_dir = "C:\php\ext"

And it worked. Of course, I did the other things also like uncommenting the dll extensions etc, as explained in others remarks.

Two decimal places using printf( )

Try using a format like %d.%02d

int iAmount = 10050;
printf("The number with fake decimal point is %d.%02d", iAmount/100, iAmount%100);

Another approach is to type cast it to double before printing it using %f like this:

printf("The number with fake decimal point is %0.2f", (double)(iAmount)/100);

My 2 cents :)

possible EventEmitter memory leak detected

I prefer to hunt down and fix problems instead of suppressing logs whenever possible. After a couple days of observing this issue in my app, I realized I was setting listeners on the req.socket in an Express middleware to catch socket io errors that kept popping up. At some point, I learned that that was not necessary, but I kept the listeners around anyway. I just removed them and the error you are experiencing went away. I verified it was the cause by running requests to my server with and without the following middleware:

socketEventsHandler(req, res, next) {
        req.socket.on("error", function(err) {
            console.error('------REQ ERROR')
            console.error(err.stack)
        });
        res.socket.on("error", function(err) {
            console.error('------RES ERROR')
            console.error(err.stack)
        });
        next();
    }

Removing that middleware stopped the warning you are seeing. I would look around your code and try to find anywhere you may be setting up listeners that you don't need.

What is the most efficient way to create HTML elements using jQuery?

If you have a lot of HTML content (more than just a single div), you might consider building the HTML into the page within a hidden container, then updating it and making it visible when needed. This way, a large portion of your markup can be pre-parsed by the browser and avoid getting bogged down by JavaScript when called. Hope this helps!

Fastest way to write huge data in text file Java

For those who want to improve the time for retrieval of records and dump into the file (i.e no processing on records), instead of putting them into an ArrayList, append those records into a StringBuffer. Apply toSring() function to get a single String and write it into the file at once.

For me, the retrieval time reduced from 22 seconds to 17 seconds.

How to set default value for HTML select?

Note: this is JQuery. See Sébastien answer for Javascript

$(function() {
    var temp="a"; 
    $("#MySelect").val(temp);
});

<select name="MySelect" id="MySelect">
    <option value="a">a</option>
    <option value="b">b</option>
    <option value="c">c</option>
</select>

Prevent browser caching of AJAX call result

Internet Explorer’s Ajax Caching: What Are YOU Going To Do About It? suggests three approaches:

  1. Add a cache busting token to the query string, like ?date=[timestamp]. In jQuery and YUI you can tell them to do this automatically.
  2. Use POST instead of a GET
  3. Send a HTTP response header that specifically forbids browsers to cache it

asterisk : Unable to connect to remote asterisk (does /var/run/asterisk.ctl exist?)

It's probably because asterisk is not running on your server.

Try to run it with this command :

asterisk -vvvvvvc

You'll enter into the Asterisk CLI and if something goes wrong you'll see it. After that you can quit the CLI by entering the exit command. Then you can reconnect to the CLI by typing asterisk -r. All this commands assumed you're the root user. If you are not root prefix them by sudo, by example sudo asterisk -vvvvvvc.

Hope it helps, regards, Duc.

Eclipse not recognizing JVM 1.8

I have had the same problem as noted above. I could not get Eclipse to install because of Java incompatibilities. The sequence I followed goes like this:

  1. Upgraded to MAC OS Sierra
  2. Downloaded the Eclipse installer but was prompted that I needed to instal a legacy Java.
  3. Installed Java 1.6
  4. Was unable to install Eclipse and was prompted that I needed Java 1.7 or greater. Downloaded and installed Java 1.8
  5. Ran the terminal code 'java -version' // this will check your jre version. This showed returned Java 1.6 despite the fact that I had upgraded to 1.8. The Java version listed in the Java control panel said 1.8
  6. Tried multiple downloads of eclipse and Java and multiple restarts always with the same result.
  7. Visited the Oracle web page noted above: http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html I could not find the above reference to 8u73 and 8u74 but I did find and option to download 1.8.0_12. I did this. It installed without difficulty, and then I was able to install Eclipse without difficulty.

This took hours of my time. I hope this proves useful.

How to get IP address of running docker container

Use --format option to get only the IP address instead whole container info:

sudo docker inspect --format '{{ .NetworkSettings.IPAddress }}' <CONTAINER ID>

Tool to compare directories (Windows 7)

I use WinMerge. It is free and works pretty well (works for files and directories).

Add A Year To Today's Date

You can create a new date object with todays date using the following code:

_x000D_
_x000D_
var d = new Date();_x000D_
    console.log(d);
_x000D_
_x000D_
_x000D_ // => Sun Oct 11 2015 14:46:51 GMT-0700 (PDT)

If you want to create a date a specific time, you can pass the new Date constructor arguments

_x000D_
_x000D_
 var d = new Date(2014);_x000D_
    console.log(d)
_x000D_
_x000D_
_x000D_

// => Wed Dec 31 1969 16:00:02 GMT-0800 (PST)

If you want to take todays date and add a year, you can first create a date object, access the relevant properties, and then use them to create a new date object

_x000D_
_x000D_
var d = new Date();_x000D_
    var year = d.getFullYear();_x000D_
    var month = d.getMonth();_x000D_
    var day = d.getDate();_x000D_
    var c = new Date(year + 1, month, day);_x000D_
    console.log(c);
_x000D_
_x000D_
_x000D_

// => Tue Oct 11 2016 00:00:00 GMT-0700 (PDT)

You can read more about the methods on the date object on MDN

Date Object

TypeScript: Creating an empty typed container array

The existing answers missed an option, so here's a complete list:

// 1. Explicitly declare the type
var arr: Criminal[] = [];

// 2. Via type assertion
var arr = <Criminal[]>[];
var arr = [] as Criminal[];

// 3. Using the Array constructor
var arr = new Array<Criminal>();
  1. Explicitly specifying the type is the general solution for whenever type inference fails for a variable declaration.

  2. The advantage of using a type assertion (sometimes called a cast, but it's not really a cast in TypeScript) works for any expression, so it can be used even when no variable is declared. There are two syntaxes for type assertions, but only the latter will work in combination with JSX if you care about that.

  3. Using the Array constructor is something that will only help you in this specific use case, but which I personally find the most readable. However, there is a slight performance impact at runtime*. Also, if someone were crazy enough to redefine the Array constructor, the meaning could change.

It's a matter of personal preference, but I find the third option the most readable. In the vast majority of cases the mentioned downsides would be negligible and readability is the most important factor.

*: Fun fact; at the time of writing the performance difference was 60% in Chrome, while in Firefox there was no measurable performance difference.

Error Installing Homebrew - Brew Command Not Found

This was just happening to me, but none of the suggestions above worked. I changed directories ("cd ~/tmp") and suddenly the command

ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"

worked for me. Prior to changing directories I had been in a directory that is a Git repository. Perhaps that was interfering with the ruby and Git commands in the Brew install script.

Multiple INSERT statements vs. single INSERT with multiple VALUES

Addition: SQL Server 2012 shows some improved performance in this area but doesn't seem to tackle the specific issues noted below. This should apparently be fixed in the next major version after SQL Server 2012!

Your plan shows the single inserts are using parameterised procedures (possibly auto parameterised) so parse/compile time for these should be minimal.

I thought I'd look into this a bit more though so set up a loop (script) and tried adjusting the number of VALUES clauses and recording the compile time.

I then divided the compile time by the number of rows to get the average compile time per clause. The results are below

Graph

Up until 250 VALUES clauses present the compile time / number of clauses has a slight upward trend but nothing too dramatic.

Graph

But then there is a sudden change.

That section of the data is shown below.

+------+----------------+-------------+---------------+---------------+
| Rows | CachedPlanSize | CompileTime | CompileMemory | Duration/Rows |
+------+----------------+-------------+---------------+---------------+
|  245 |            528 |          41 |          2400 | 0.167346939   |
|  246 |            528 |          40 |          2416 | 0.162601626   |
|  247 |            528 |          38 |          2416 | 0.153846154   |
|  248 |            528 |          39 |          2432 | 0.157258065   |
|  249 |            528 |          39 |          2432 | 0.156626506   |
|  250 |            528 |          40 |          2448 | 0.16          |
|  251 |            400 |         273 |          3488 | 1.087649402   |
|  252 |            400 |         274 |          3496 | 1.087301587   |
|  253 |            400 |         282 |          3520 | 1.114624506   |
|  254 |            408 |         279 |          3544 | 1.098425197   |
|  255 |            408 |         290 |          3552 | 1.137254902   |
+------+----------------+-------------+---------------+---------------+

The cached plan size which had been growing linearly suddenly drops but CompileTime increases 7 fold and CompileMemory shoots up. This is the cut off point between the plan being an auto parametrized one (with 1,000 parameters) to a non parametrized one. Thereafter it seems to get linearly less efficient (in terms of number of value clauses processed in a given time).

Not sure why this should be. Presumably when it is compiling a plan for specific literal values it must perform some activity that does not scale linearly (such as sorting).

It doesn't seem to affect the size of the cached query plan when I tried a query consisting entirely of duplicate rows and neither affects the order of the output of the table of the constants (and as you are inserting into a heap time spent sorting would be pointless anyway even if it did).

Moreover if a clustered index is added to the table the plan still shows an explicit sort step so it doesn't seem to be sorting at compile time to avoid a sort at run time.

Plan

I tried to look at this in a debugger but the public symbols for my version of SQL Server 2008 don't seem to be available so instead I had to look at the equivalent UNION ALL construction in SQL Server 2005.

A typical stack trace is below

sqlservr.exe!FastDBCSToUnicode()  + 0xac bytes  
sqlservr.exe!nls_sqlhilo()  + 0x35 bytes    
sqlservr.exe!CXVariant::CmpCompareStr()  + 0x2b bytes   
sqlservr.exe!CXVariantPerformCompare<167,167>::Compare()  + 0x18 bytes  
sqlservr.exe!CXVariant::CmpCompare()  + 0x11f67d bytes  
sqlservr.exe!CConstraintItvl::PcnstrItvlUnion()  + 0xe2 bytes   
sqlservr.exe!CConstraintProp::PcnstrUnion()  + 0x35e bytes  
sqlservr.exe!CLogOp_BaseSetOp::PcnstrDerive()  + 0x11a bytes    
sqlservr.exe!CLogOpArg::PcnstrDeriveHandler()  + 0x18f bytes    
sqlservr.exe!CLogOpArg::DeriveGroupProperties()  + 0xa9 bytes   
sqlservr.exe!COpArg::DeriveNormalizedGroupProperties()  + 0x40 bytes    
sqlservr.exe!COptExpr::DeriveGroupProperties()  + 0x18a bytes   
sqlservr.exe!COptExpr::DeriveGroupProperties()  + 0x146 bytes   
sqlservr.exe!COptExpr::DeriveGroupProperties()  + 0x146 bytes   
sqlservr.exe!COptExpr::DeriveGroupProperties()  + 0x146 bytes   
sqlservr.exe!CQuery::PqoBuild()  + 0x3cb bytes  
sqlservr.exe!CStmtQuery::InitQuery()  + 0x167 bytes 
sqlservr.exe!CStmtDML::InitNormal()  + 0xf0 bytes   
sqlservr.exe!CStmtDML::Init()  + 0x1b bytes 
sqlservr.exe!CCompPlan::FCompileStep()  + 0x176 bytes   
sqlservr.exe!CSQLSource::FCompile()  + 0x741 bytes  
sqlservr.exe!CSQLSource::FCompWrapper()  + 0x922be bytes    
sqlservr.exe!CSQLSource::Transform()  + 0x120431 bytes  
sqlservr.exe!CSQLSource::Compile()  + 0x2ff bytes   

So going off the names in the stack trace it appears to spend a lot of time comparing strings.

This KB article indicates that DeriveNormalizedGroupProperties is associated with what used to be called the normalization stage of query processing

This stage is now called binding or algebrizing and it takes the expression parse tree output from the previous parse stage and outputs an algebrized expression tree (query processor tree) to go forward to optimization (trivial plan optimization in this case) [ref].

I tried one more experiment (Script) which was to re-run the original test but looking at three different cases.

  1. First Name and Last Name Strings of length 10 characters with no duplicates.
  2. First Name and Last Name Strings of length 50 characters with no duplicates.
  3. First Name and Last Name Strings of length 10 characters with all duplicates.

Graph

It can clearly be seen that the longer the strings the worse things get and that conversely the more duplicates the better things get. As previously mentioned duplicates don't affect the cached plan size so I presume that there must be a process of duplicate identification when constructing the algebrized expression tree itself.

Edit

One place where this information is leveraged is shown by @Lieven here

SELECT * 
FROM (VALUES ('Lieven1', 1),
             ('Lieven2', 2),
             ('Lieven3', 3))Test (name, ID)
ORDER BY name, 1/ (ID - ID) 

Because at compile time it can determine that the Name column has no duplicates it skips ordering by the secondary 1/ (ID - ID) expression at run time (the sort in the plan only has one ORDER BY column) and no divide by zero error is raised. If duplicates are added to the table then the sort operator shows two order by columns and the expected error is raised.

How do you run a crontab in Cygwin on Windows?

Applied the instructions from this answer and it worked Just to point out a more copy paste like answer ( because cygwin installation procedure is kind of anti-copy-paste wise implemented )
Click WinLogo button , type cmd.exe , right click it , choose "Start As Administrator". In cmd prompt:

 cd <directory_where_i_forgot_the setup-x86_64.exe> cygwin installer:
 set package_name=cygrunsrv cron
 setup-x86_64.exe -n -q -s http://cygwin.mirror.constant.com -P %package_name%

Ensure the installer does not throw any errors in the prompt ... If it has - you probably have some cygwin binaries running or you are not an Windows admin, or some freaky bug ...

Now in cmd promt:

 C:\cygwin64\bin\cygrunsrv.exe -I cron -p /usr/sbin/cron -a -D   

or whatever full file path you might have to the cygrunsrv.exe and start the cron as windows service in the cmd prompt

 net start cron

Now in bash terminal run crontab -e

set up you cron entry an example bellow:

        #sync my gdrive each 10th minute
    */10 * * * * /home/Yordan/sync_gdrive.sh

    # * * * * * command to be executed
    # - - - - -
    # | | | | |
    # | | | | +- - - - day of week (0 - 6) (Sunday=0)
    # | | | +- - - - - month (1 - 12)
    # | | +- - - - - - day of month (1 - 31)
    # | +- - - - - - - hour (0 - 23)
    # +--------------- minute

How can I create an editable dropdownlist in HTML?

You can accomplish this by using the <datalist> tag in HTML5.

_x000D_
_x000D_
<input type="text" name="product" list="productName"/>
    <datalist id="productName">
        <option value="Pen">Pen</option>
        <option value="Pencil">Pencil</option>
        <option value="Paper">Paper</option>
    </datalist>
_x000D_
_x000D_
_x000D_

If you double click on the input text in the browser a list with the defined option will appear.

Convert a string to datetime in PowerShell

ParseExact is told the format of the date it is expected to parse, not the format you wish to get out.

$invoice = '01-Jul-16'
[datetime]::parseexact($invoice, 'dd-MMM-yy', $null)

If you then wish to output a date string:

[datetime]::parseexact($invoice, 'dd-MMM-yy', $null).ToString('yyyy-MM-dd')

Chris

How does C compute sin() and other math functions?

In GNU libm, the implementation of sin is system-dependent. Therefore you can find the implementation, for each platform, somewhere in the appropriate subdirectory of sysdeps.

One directory includes an implementation in C, contributed by IBM. Since October 2011, this is the code that actually runs when you call sin() on a typical x86-64 Linux system. It is apparently faster than the fsin assembly instruction. Source code: sysdeps/ieee754/dbl-64/s_sin.c, look for __sin (double x).

This code is very complex. No one software algorithm is as fast as possible and also accurate over the whole range of x values, so the library implements several different algorithms, and its first job is to look at x and decide which algorithm to use.

  • When x is very very close to 0, sin(x) == x is the right answer.

  • A bit further out, sin(x) uses the familiar Taylor series. However, this is only accurate near 0, so...

  • When the angle is more than about 7°, a different algorithm is used, computing Taylor-series approximations for both sin(x) and cos(x), then using values from a precomputed table to refine the approximation.

  • When |x| > 2, none of the above algorithms would work, so the code starts by computing some value closer to 0 that can be fed to sin or cos instead.

  • There's yet another branch to deal with x being a NaN or infinity.

This code uses some numerical hacks I've never seen before, though for all I know they might be well-known among floating-point experts. Sometimes a few lines of code would take several paragraphs to explain. For example, these two lines

double t = (x * hpinv + toint);
double xn = t - toint;

are used (sometimes) in reducing x to a value close to 0 that differs from x by a multiple of π/2, specifically xn × π/2. The way this is done without division or branching is rather clever. But there's no comment at all!


Older 32-bit versions of GCC/glibc used the fsin instruction, which is surprisingly inaccurate for some inputs. There's a fascinating blog post illustrating this with just 2 lines of code.

fdlibm's implementation of sin in pure C is much simpler than glibc's and is nicely commented. Source code: fdlibm/s_sin.c and fdlibm/k_sin.c

List distinct values in a vector in R

Do you mean unique:

R> x = c(1,1,2,3,4,4,4)
R> x
[1] 1 1 2 3 4 4 4
R> unique(x)
[1] 1 2 3 4

How do I compare two strings in Perl?

  • cmp Compare

    'a' cmp 'b' # -1
    'b' cmp 'a' #  1
    'a' cmp 'a' #  0
    
  • eq Equal to

    'a' eq  'b' #  0
    'b' eq  'a' #  0
    'a' eq  'a' #  1
    
  • ne Not-Equal to

    'a' ne  'b' #  1
    'b' ne  'a' #  1
    'a' ne  'a' #  0
    
  • lt Less than

    'a' lt  'b' #  1
    'b' lt  'a' #  0
    'a' lt  'a' #  0
    
  • le Less than or equal to

    'a' le  'b' #  1
    'b' le  'a' #  0
    'a' le  'a' #  1
    
  • gt Greater than

    'a' gt  'b' #  0
    'b' gt  'a' #  1
    'a' gt  'a' #  0
    
  • ge Greater than or equal to

    'a' ge  'b' #  0
    'b' ge  'a' #  1
    'a' ge  'a' #  1
    

See perldoc perlop for more information.

( I'm simplifying this a little bit as all but cmp return a value that is both an empty string, and a numerically zero value instead of 0, and a value that is both the string '1' and the numeric value 1. These are the same values you will always get from boolean operators in Perl. You should really only be using the return values for boolean or numeric operations, in which case the difference doesn't really matter. )

Capture the screen shot using .NET

It's certainly possible to grab a screenshot using the .NET Framework. The simplest way is to create a new Bitmap object and draw into that using the Graphics.CopyFromScreen method.

Sample code:

using (Bitmap bmpScreenCapture = new Bitmap(Screen.PrimaryScreen.Bounds.Width, 
                                            Screen.PrimaryScreen.Bounds.Height))
using (Graphics g = Graphics.FromImage(bmpScreenCapture))
{
    g.CopyFromScreen(Screen.PrimaryScreen.Bounds.X,
                     Screen.PrimaryScreen.Bounds.Y,
                     0, 0,
                     bmpScreenCapture.Size,
                     CopyPixelOperation.SourceCopy);
}

Caveat: This method doesn't work properly for layered windows. Hans Passant's answer here explains the more complicated method required to get those in your screen shots.

How to get access to raw resources that I put in res folder?

This worked for for me: getResources().openRawResource(R.raw.certificate)

Java: recommended solution for deep cloning/copying an instance

I'd recommend the DIY way which, combined with a good hashCode() and equals() method should be easy to proof in a unit test.

Updates were rejected because the tip of your current branch is behind its remote counterpart

Set current branch name like master

git pull --rebase origin master git push origin master

Or branch name develop

git pull --rebase origin develop git push origin develop

Extracting extension from filename in Python

Any of the solutions above work, but on linux I have found that there is a newline at the end of the extension string which will prevent matches from succeeding. Add the strip() method to the end. For example:

import os.path
extension = os.path.splitext(filename)[1][1:].strip() 

Check if pull needed in Git

There are many very feature rich and ingenious answers already. To provide some contrast, I could make do with a very simple line.

# Check return value to see if there are incoming updates.
if ! git diff --quiet remotes/origin/HEAD; then
 # pull or whatever you want to do
fi

Xcode 10 Error: Multiple commands produce

I found the solution for this build error, for anybody else having the same issue with Xcode 10 build system, follow the following steps to fix it:

  1. In Xcode, go to File->Project/Workspace settings.
  2. Change the build system to Legacy Build system.

enter image description here It will resolve the build issue with the new Xcode 10.

If you want to work with the new build system, then you can find the troubleshooting help from this apple Xcode help page.

Hope this helps!

How can I get a count of the total number of digits in a number?

int i = 855865264;
int NumLen = i.ToString().Length;

Dynamic function name in javascript?

Thank you Marcosc! Building on his answer, if you want to rename any function, use this:

// returns the function named with the passed name
function namedFunction(name, fn) {
    return new Function('fn',
        "return function " + name + "(){ return fn.apply(this,arguments)}"
    )(fn)
}

Checking character length in ruby

Verification, do not forget the to_s

 def nottolonng?(value)
   if value.to_s.length <=8
     return true
   else
     return false
   end
  end

How to list files in a directory in a C program?

One tiny addition to JB Jansen's answer - in the main readdir() loop I'd add this:

  if (dir->d_type == DT_REG)
  {
     printf("%s\n", dir->d_name);
  }

Just checking if it's really file, not (sym)link, directory, or whatever.

NOTE: more about struct dirent in libc documentation.

How to return history of validation loss in Keras

For plotting the loss directly the following works:

model_ = model.fit(X, Y, epochs= ..., verbose=1 )
plt.plot(list(model_.history.values())[0],'k-o')

H2 in-memory database. Table not found

When opening the h2-console, the JDBC URL must match the one specified in the properties:

spring.datasource.driverClassName=org.h2.Driver
spring.datasource.url=jdbc:h2:mem:testdb

spring.jpa.hibernate.ddl-auto=create
spring.jpa.show-sql=true

spring.h2.console.enabled=true

enter image description here

Which seems obvious, but I spent hours figuring this out..

Creating a daemon in Linux

Try using the daemon function:

#include <unistd.h>

int daemon(int nochdir, int noclose);

From the man page:

The daemon() function is for programs wishing to detach themselves from the controlling terminal and run in the background as system daemons.

If nochdir is zero, daemon() changes the calling process's current working directory to the root directory ("/"); otherwise, the current working directory is left unchanged.

If noclose is zero, daemon() redirects standard input, standard output and standard error to /dev/null; otherwise, no changes are made to these file descriptors.

Any way to exit bash script, but not quitting the terminal

I think that this happens because you are running it on source mode with the dot

. myscript.sh

You should run that in a subshell:

/full/path/to/script/myscript.sh

'source' http://ss64.com/bash/source.html

Is it possible to use the SELECT INTO clause with UNION [ALL]?

Maybe try this?

SELECT * INTO tmpFerdeen (
SELECT top(100)* 
FROM Customers
UNION All
SELECT top(100)* 
FROM CustomerEurope
UNION All
SELECT top(100)* 
FROM CustomerAsia
UNION All
SELECT top(100)* 
FROM CustomerAmericas)

How to return a result (startActivityForResult) from a TabHost Activity?

http://tylenoly.wordpress.com/2010/10/27/how-to-finish-activity-with-results/

With a slight modification for "param_result"

/* Start Activity */
public void onClick(View v) {
    Intent intent = new Intent(Intent.ACTION_VIEW);
    intent.setClassName("com.thinoo.ActivityTest", "com.thinoo.ActivityTest.NewActivity");
    startActivityForResult(intent,90);
}
/* Called when the second activity's finished */
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch(requestCode) {
    case 90:
        if (resultCode == RESULT_OK) {
            Bundle res = data.getExtras();
            String result = res.getString("param_result");
            Log.d("FIRST", "result:"+result);
        }
        break;
    }
}

private void finishWithResult()
{
    Bundle conData = new Bundle();
    conData.putString("param_result", "Thanks Thanks");
    Intent intent = new Intent();
    intent.putExtras(conData);
    setResult(RESULT_OK, intent);
    finish();
}

python max function using 'key' and lambda expression

max is built in function which takes first argument an iterable (like list or tuple)

keyword argument key has it's default value None but it accept function to evaluate, consider it as wrapper which evaluates iterable based on function

Consider this example dictionary:

d = {'aim':99, 'aid': 45, 'axe': 59, 'big': 9, 'short': 995, 'sin':12, 'sword':1, 'friend':1000, 'artwork':23}

Ex:

>>> max(d.keys())
'sword'

As you can see if you only pass the iterable without kwarg(a function to key) it is returning maximum value of key(alphabetically)

Ex. Instead of finding max value of key alphabetically you might need to find max key by length of key:

>>>max(d.keys(), key=lambda x: len(x))
'artwork'

in this example lambda function is returning length of key which will be iterated hence while evaluating values instead of considering alphabetically it will keep track of max length of key and returns key which has max length

Ex.

>>> max(d.keys(), key=lambda x: d[x])
'friend'

in this example lambda function is returning value of corresponding dictionary key which has maximum value

How to right-align form input boxes?

Try this:

<!DOCTYPE html>
<html>
<head>
    <style type="text/css">
    p {
        text-align: right;
    }
    input {
        width: 100px;
    }
    </style>
</head>

<body>
    <form>
        <p>
            <input name="declared_first" value="above" />
        </p>
        <p>
            <input name="declared_second" value="below" />
        </p>
    </form>
</body>
</html>

Inner join vs Where

In PostgreSQL, there's definitely no difference - they both equate to the same query plan. I'm 99% sure that's also the case for Oracle.

Zip folder in C#

There's nothing in the BCL to do this for you, but there are two great libraries for .NET which do support the functionality.

I've used both and can say that the two are very complete and have well-designed APIs, so it's mainly a matter of personal preference.

I'm not sure whether they explicitly support adding Folders rather than just individual files to zip files, but it should be quite easy to create something that recursively iterated over a directory and its sub-directories using the DirectoryInfo and FileInfo classes.

How to Delete Session Cookie?

A session cookie is just a normal cookie without an expiration date. Those are handled by the browser to be valid until the window is closed or program is quit.

But if the cookie is a httpOnly cookie (a cookie with the httpOnly parameter set), you cannot read, change or delete it from outside of HTTP (meaning it must be changed on the server).

How to create file object from URL object (image)

You can make use of ImageIO in order to load the image from an URL and then write it to a file. Something like this:

URL url = new URL("http://google.com/pathtoaimage.jpg");
BufferedImage img = ImageIO.read(url);
File file = new File("downloaded.jpg");
ImageIO.write(img, "jpg", file);

This also allows you to convert the image to some other format if needed.

Complete list of reasons why a css file might not be working

Copy the css file's url and paste it into your browser. If it doesn't load the file than you know the problem is in the url.

What is the correct way to do a CSS Wrapper?

/******************
Fit the body to the edges of the screen
******************/    

body {
         margin:0;
         padding:0;
    }

header {
     background:black;
     width:100%;
}

.header {
     height:200px;
}

nav {
     width:100%;
     background:lightseagreen;
}

.nav {
     padding:0;
     margin:0;
}

.nav a {
     padding:10px;
     font-family:tahoma;
     font-size:12pt;
     color:white;
}

/******************
Centered wrapper, all other content divs will go inside this and will never exceed the width of 960px.
******************/

    .wrapper {
         width:960px;
         max-width:100%;
         margin:0 auto;
    }



<!-------- Start HTML ---------->

    <body>

<header>

    <div id="header" class="wrapper">

    </div>

</header>

<nav>

     <div id="nav" class="wrapper">

     </div>

</nav>



    </body>