Programs & Examples On #Treap

Iframe transparent background

I've used this creating an IFrame through Javascript and it worked for me:

// IFrame points to the IFrame element, obviously
IFrame.src = 'about: blank';
IFrame.style.backgroundColor = "transparent";
IFrame.frameBorder = "0";
IFrame.allowTransparency="true";

Not sure if it makes any difference, but I set those properties before adding the IFrame to the DOM. After adding it to the DOM, I set its src to the real URL.

How to override a JavaScript function

var origParseFloat = parseFloat;
parseFloat = function(str) {
     alert("And I'm in your floats!");
     return origParseFloat(str);
}

Can someone provide an example of a $destroy event for scopes in AngularJS?

$destroy can refer to 2 things: method and event

1. method - $scope.$destroy

.directive("colorTag", function(){
  return {
    restrict: "A",
    scope: {
      value: "=colorTag"
    },
    link: function (scope, element, attrs) {
      var colors = new App.Colors();
      element.css("background-color", stringToColor(scope.value));
      element.css("color", contrastColor(scope.value));

      // Destroy scope, because it's no longer needed.
      scope.$destroy();
    }
  };
})

2. event - $scope.$on("$destroy")

See @SunnyShah's answer.

Getting the computer name in Java

The computer "name" is resolved from the IP address by the underlying DNS (Domain Name System) library of the OS. There's no universal concept of a computer name across OSes, but DNS is generally available. If the computer name hasn't been configured so DNS can resolve it, it isn't available.

import java.net.InetAddress;
import java.net.UnknownHostException;

String hostname = "Unknown";

try
{
    InetAddress addr;
    addr = InetAddress.getLocalHost();
    hostname = addr.getHostName();
}
catch (UnknownHostException ex)
{
    System.out.println("Hostname can not be resolved");
}

SQL query for a carriage return in a string and ultimately removing carriage return

this works: select * from table where column like '%(hit enter)%'

Ignore the brackets and hit enter to introduce new line.

JavaScript blob filename without link

Working example of a download button, to save a cat photo from an url as "cat.jpg":

HTML:

<button onclick="downloadUrl('https://i.imgur.com/AD3MbBi.jpg', 'cat.jpg')">Download</button>

JavaScript:

function downloadUrl(url, filename) {
  let xhr = new XMLHttpRequest();
  xhr.open("GET", url, true);
  xhr.responseType = "blob";
  xhr.onload = function(e) {
    if (this.status == 200) {
      const blob = this.response;
      const a = document.createElement("a");
      document.body.appendChild(a);
      const blobUrl = window.URL.createObjectURL(blob);
      a.href = blobUrl;
      a.download = filename;
      a.click();
      setTimeout(() => {
        window.URL.revokeObjectURL(blobUrl);
        document.body.removeChild(a);
      }, 0);
    }
  };
  xhr.send();
}

iOS: UIButton resize according to text length

The way to do this in code is:

[button sizeToFit];

If you are subclassing and want to add extra rules you can override:

- (CGSize)sizeThatFits:(CGSize)size;

No grammar constraints (DTD or XML schema) detected for the document

i know this is old but I'm passing trought the same problem and found the solution in the spring documentation, the following xml configuration has been solved the problem for me.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc" 
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/mvc 
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http://www.springframework.org/schema/tx 

<!-- THIS IS THE LINE THAT SOLVE MY PROBLEM -->
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd 

http://www.springframework.org/schema/beans 
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context 
http://www.springframework.org/schema/context/spring-context-3.0.xsd">

before I put the line above as sugested in this forum topic , I have the same warning message, and placing this...

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xml>

and it give me the following warning message...

The content of element type "template" must match "
(description,variation?,variation-field?,allow- multiple-variation?,class-
pattern?,getter-setter?,allowed-file-extensions?,number-required- 
classes?,template-body)".

so just try to use the sugested lines of my xml configuration.

What is __gxx_personality_v0 for?

It's part of the exception handling. The gcc EH mechanism allows to mix various EH models, and a personality routine is invoked to determine if an exception match, what finalization to invoke, etc. This specific personality routine is for C++ exception handling (as opposed to, say, gcj/Java exception handling).

How to build query string with Javascript

Create an URL object and append the values to seachParameters

let baseURL = "http://www.google.com/search";
let url = new URL(baseURL);
let params = url.searchParams;
    params.append("q","This is seach query");

console.log( url.toString() );

Replace all elements of Python NumPy Array that are greater than some value

Lets us assume you have a numpy array that has contains the value from 0 all the way up to 20 and you want to replace numbers greater than 10 with 0

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_x000D_
import numpy as np

my_arr = np.arange(0,21) # creates an array
my_arr[my_arr > 10] = 0 # modifies the value
_x000D_
_x000D_
_x000D_

Note this will however modify the original array to avoid overwriting the original array try using arr.copy() to create a new detached copy of the original array and modify that instead.

_x000D_
_x000D_
import numpy as np

my_arr = np.arange(0,21)
my_arr_copy = my_arr.copy() # creates copy of the orignal array

my_arr_copy[my_arr_copy > 10] = 0 
_x000D_
_x000D_
_x000D_

Bootstrap 3 Navbar with Logo

<header class="navbar navbar-inverse header-outer" role="banner">
  <div class="container form-inline">
    <img src="@Url.Content(" ~/Content/img/Logo-Sample.png ")" alt="Image" id="logo" class="img-responsive pull-left" />

    <div class="pull-right padding-top">
      <form class="hidden-xs" role="form">

        <div class="form-group" style="padding-left:10px">
          <input type="email" class="form-control" id="exampleInputEmail2" placeholder="Username">
        </div>

        <div class="form-group">
          <input type="password" class="form-control" id="exampleInputPassword2" placeholder="Password">
        </div>
        <div class="form-group navbar-remember">
          <label class="white-font">
            <input type="checkbox" class="white-font"> Remember me
          </label>
        </div>
        <button type="button" class="btn btn-primary form-group" title="Sign In">Sign In</button>
      </form>
    </div>
  </div>

</header>

Please understand the code at your own effort :D This is my draft code and its already working :) Here's the screenshot.

enter image description here

HTML select drop-down with an input field

You can use input text with "list" attribute, which refers to the datalist of values.

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_x000D_
<input type="text" name="city" list="cityname">_x000D_
    <datalist id="cityname">_x000D_
      <option value="Boston">_x000D_
      <option value="Cambridge">_x000D_
    </datalist>
_x000D_
_x000D_
_x000D_

This creates a free text input field that also has a drop-down to select predefined choices. Attribution for example and more information: https://www.w3.org/wiki/HTML/Elements/datalist

Unprotect workbook without password

No longer works for spreadsheets Protected with Excel 2013 or later -- they improved the pw hash. So now need to unzip .xlsx and hack the internals.

Send data from activity to fragment in Android

This answer may be too late. but it will be useful for future readers.

I have some criteria. I have coded for pick the file from intent. and selected file to be passed to particular fragment for further process. i have many fragments having the functionality of File picking. at the time , every time checking the condition and get the fragment and pass the value is quite disgusting. so , i have decided to pass the value using interface.

Step 1: Create the interface on Main Activity.

   public interface SelectedBundle {
    void onBundleSelect(Bundle bundle);
   }

Step 2: Create the SelectedBundle reference on the Same Activity

   SelectedBundle selectedBundle;

Step 3: create the Method in the Same Activity

   public void setOnBundleSelected(SelectedBundle selectedBundle) {
       this.selectedBundle = selectedBundle;
   }

Step 4: Need to initialise the SelectedBundle reference which are all fragment need filepicker functionality.You place this code on your fragment onCreateView(..) method

    ((MainActivity)getActivity()).setOnBundleSelected(new MainActivity.SelectedBundle() {
          @Override
         public void onBundleSelect(Bundle bundle) {
            updateList(bundle);
        }
     });

Step 5: My case, i need to pass the image Uri from HomeActivity to fragment. So, i used this functionality on onActivityResult method.

onActivityResult from the MainActivity, pass the values to the fragments using interface.

Note: Your case may be different. you can call it from any where from your HomeActivity.

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

Thats all. Implement every fragment you needed on the FragmentClass. You are great. you have done. WOW...

What is a blob URL and why it is used?

What is blob url? Why it is used?

BLOB is just byte sequence. Browser recognize it as byte stream. It is used to get byte stream from source.

A Blob object represents a file-like object of immutable, raw data. Blobs represent data that isn't necessarily in a JavaScript-native format. The File interface is based on Blob, inheriting blob functionality and expanding it to support files on the user's system.

Can i make my own blob url on a server?

Yes you can there are serveral ways to do so for example try http://php.net/manual/en/function.ibase-blob-echo.php

Read more on

UIDevice uniqueIdentifier deprecated - What to do now?

UIDevice identifierForVendor introduced in iOS 6 would work for your purposes.

identifierForVendor is an alphanumeric string that uniquely identifies a device to the app’s vendor. (read-only)

@property(nonatomic, readonly, retain) NSUUID *identifierForVendor

The value of this property is the same for apps that come from the same vendor running on the same device. A different value is returned for apps onthe same device that come from different vendors, and for apps on different devices regardles of vendor.

Available in iOS 6.0 and later and declared in UIDevice.h

For iOS 5 refer this link UIDevice-with-UniqueIdentifier-for-iOS-5

How can I convert uppercase letters to lowercase in Notepad++

Ctrl+A , Ctrl+Shift+U

should do the trick!

Edit: Ctrl+U is the shortcut to be used to convert capital letters to lowercase (reverse scenario)

"Fatal error: Unable to find local grunt." when running "grunt" command

All is explained quite nicely on gruntjs.com.

Note that installing grunt-cli does not install the grunt task runner! The job of the grunt CLI is simple: run the version of grunt which has been installed next to a Gruntfile. This allows multiple versions of grunt to be installed on the same machine simultaneously.

So in your project folder, you will need to install (preferably) the latest grunt version:

npm install grunt --save-dev

Option --save-dev will add grunt as a dev-dependency to your package.json. This makes it easy to reinstall dependencies.

Difference between View and Request scope in managed beans

A @ViewScoped bean lives exactly as long as a JSF view. It usually starts with a fresh new GET request, or with a navigation action, and will then live as long as the enduser submits any POST form in the view to an action method which returns null or void (and thus navigates back to the same view). Once you refresh the page, or return a non-null string (even an empty string!) navigation outcome, then the view scope will end.

A @RequestScoped bean lives exactly as long a HTTP request. It will thus be garbaged by end of every request and recreated on every new request, hereby losing all changed properties.

A @ViewScoped bean is thus particularly more useful in rich Ajax-enabled views which needs to remember the (changed) view state across Ajax requests. A @RequestScoped one would be recreated on every Ajax request and thus fail to remember all changed view state. Note that a @ViewScoped bean does not share any data among different browser tabs/windows in the same session like as a @SessionScoped bean. Every view has its own unique @ViewScoped bean.

See also:

Excel VBA - select multiple columns not in sequential order

Some things of top of my head.

Method 1.

Application.Union(Range("a1"), Range("b1"), Range("d1"), Range("e1"), Range("g1"), Range("h1")).EntireColumn.Select

Method 2.

Range("a1,b1,d1,e1,g1,h1").EntireColumn.Select

Method 3.

Application.Union(Columns("a"), Columns("b"), Columns("d"), Columns("e"), Columns("g"), Columns("h")).Select

Check for a substring in a string in Oracle without LIKE

I'm guessing the reason you're asking is performance? There's the instr function. But that's likely to work pretty much the same behind the scenes.

Maybe you could look into full text search.

As last resorts you'd be looking at caching or precomputed columns/an indexed view.

Convert MySql DateTime stamp into JavaScript's Date format

Some of the answers given here are either overcomplicated or just will not work (at least, not in all browsers). If you take a step back, you can see that the MySQL timestamp has each component of time in the same order as the arguments required by the Date() constructor.

All that's needed is a very simple split on the string:

// Split timestamp into [ Y, M, D, h, m, s ]
var t = "2010-06-09 13:12:01".split(/[- :]/);

// Apply each element to the Date function
var d = new Date(Date.UTC(t[0], t[1]-1, t[2], t[3], t[4], t[5]));

console.log(d);
// -> Wed Jun 09 2010 14:12:01 GMT+0100 (BST)

Fair warning: this assumes that your MySQL server is outputting UTC dates (which is the default, and recommended if there is no timezone component of the string).

How to put a link on a button with bootstrap?

This is how I solved

   <a href="#" >
      <button type="button" class="btn btn-info">Button Text</button>
   </a>  

Seedable JavaScript random number generator

If you don't need the seeding capability just use Math.random() and build helper functions around it (eg. randRange(start, end)).

I'm not sure what RNG you're using, but it's best to know and document it so you're aware of its characteristics and limitations.

Like Starkii said, Mersenne Twister is a good PRNG, but it isn't easy to implement. If you want to do it yourself try implementing a LCG - it's very easy, has decent randomness qualities (not as good as Mersenne Twister), and you can use some of the popular constants.

EDIT: consider the great options at this answer for short seedable RNG implementations, including an LCG option.

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_x000D_
function RNG(seed) {_x000D_
  // LCG using GCC's constants_x000D_
  this.m = 0x80000000; // 2**31;_x000D_
  this.a = 1103515245;_x000D_
  this.c = 12345;_x000D_
_x000D_
  this.state = seed ? seed : Math.floor(Math.random() * (this.m - 1));_x000D_
}_x000D_
RNG.prototype.nextInt = function() {_x000D_
  this.state = (this.a * this.state + this.c) % this.m;_x000D_
  return this.state;_x000D_
}_x000D_
RNG.prototype.nextFloat = function() {_x000D_
  // returns in range [0,1]_x000D_
  return this.nextInt() / (this.m - 1);_x000D_
}_x000D_
RNG.prototype.nextRange = function(start, end) {_x000D_
  // returns in range [start, end): including start, excluding end_x000D_
  // can't modulu nextInt because of weak randomness in lower bits_x000D_
  var rangeSize = end - start;_x000D_
  var randomUnder1 = this.nextInt() / this.m;_x000D_
  return start + Math.floor(randomUnder1 * rangeSize);_x000D_
}_x000D_
RNG.prototype.choice = function(array) {_x000D_
  return array[this.nextRange(0, array.length)];_x000D_
}_x000D_
_x000D_
var rng = new RNG(20);_x000D_
for (var i = 0; i < 10; i++)_x000D_
  console.log(rng.nextRange(10, 50));_x000D_
_x000D_
var digits = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];_x000D_
for (var i = 0; i < 10; i++)_x000D_
  console.log(rng.choice(digits));
_x000D_
_x000D_
_x000D_

How to know that a string starts/ends with a specific string in jQuery?

ES6 now supports the startsWith() and endsWith() method for checking beginning and ending of strings. If you want to support pre-es6 engines, you might want to consider adding one of the suggested methods to the String prototype.

if (typeof String.prototype.startsWith != 'function') {
  String.prototype.startsWith = function (str) {
    return this.match(new RegExp("^" + str));
  };
}

if (typeof String.prototype.endsWith != 'function') {
  String.prototype.endsWith = function (str) {
    return this.match(new RegExp(str + "$"));
  };
}

var str = "foobar is not barfoo";
console.log(str.startsWith("foob"); // true
console.log(str.endsWith("rfoo");   // true

How to append the output to a file?

Use >> to append:

command >> file

How to convert string to double with proper cultureinfo

I have this function in my toolbelt since years ago (all the function and variable names are messy and mixing Spanish and English, sorry for that).

It lets the user use , and . to separate the decimals and will try to do the best if both symbols are used.

    Public Shared Function TryCDec(ByVal texto As String, Optional ByVal DefaultValue As Decimal = 0) As Decimal

        If String.IsNullOrEmpty(texto) Then
            Return DefaultValue
        End If

        Dim CurAsTexto As String = texto.Trim.Replace("$", "").Replace(" ", "")

        ''// You can probably use a more modern way to find out the
        ''// System current locale, this function was done long time ago
        Dim SepDecimal As String, SepMiles As String
        If CDbl("3,24") = 324 Then
            SepDecimal = "."
            SepMiles = ","
        Else
            SepDecimal = ","
            SepMiles = "."
        End If

        If InStr(CurAsTexto, SepDecimal) > 0 Then
            If InStr(CurAsTexto, SepMiles) > 0 Then
                ''//both symbols was used find out what was correct
                If InStr(CurAsTexto, SepDecimal) > InStr(CurAsTexto, SepMiles) Then
                    ''// The usage was correct, but get rid of thousand separator
                    CurAsTexto = Replace(CurAsTexto, SepMiles, "")
                Else
                    ''// The usage was incorrect, but get rid of decimal separator and then replace it
                    CurAsTexto = Replace(CurAsTexto, SepDecimal, "")
                    CurAsTexto = Replace(CurAsTexto, SepMiles, SepDecimal)
                End If
            End If
        Else
            CurAsTexto = Replace(CurAsTexto, SepMiles, SepDecimal)
        End If
        ''// At last we try to tryParse, just in case
        Dim retval As Decimal = DefaultValue
        Decimal.TryParse(CurAsTexto, retval)
        Return retval
    End Function

Indexing vectors and arrays with +:

Description and examples can be found in IEEE Std 1800-2017 § 11.5.1 "Vector bit-select and part-select addressing". First IEEE appearance is IEEE 1364-2001 (Verilog) § 4.2.1 "Vector bit-select and part-select addressing". Here is an direct example from the LRM:

logic [31: 0] a_vect;
logic [0 :31] b_vect;
logic [63: 0] dword;
integer sel;
a_vect[ 0 +: 8] // == a_vect[ 7 : 0]
a_vect[15 -: 8] // == a_vect[15 : 8]
b_vect[ 0 +: 8] // == b_vect[0 : 7]
b_vect[15 -: 8] // == b_vect[8 :15]
dword[8*sel +: 8] // variable part-select with fixed width

If sel is 0 then dword[8*(0) +: 8] == dword[7:0]
If sel is 7 then dword[8*(7) +: 8] == dword[63:56]

The value to the left always the starting index. The number to the right is the width and must be a positive constant. the + and - indicates to select the bits of a higher or lower index value then the starting index.

Assuming address is in little endian ([msb:lsb]) format, then if(address[2*pointer+:2]) is the equivalent of if({address[2*pointer+1],address[2*pointer]})

Unable to install pyodbc on Linux

For archlinux/manjaro:

sudo pacman -S unixodbc

then:

sudo pip install pyodbc

or:

pip install pyodbc

You can upgrade your pip wheel setuptools before installing pyodbc (it won't affect the pyodbc installation) also with:

sudo python -m pip install --upgrade pip wheel setuptools

or

python -m pip install --upgrade pip wheel setuptools

Convert a list to a data frame

assume your list is called L,

data.frame(Reduce(rbind, L))

PATH issue with pytest 'ImportError: No module named YadaYadaYada'

My solution:

create the conftest.py file in the test directory containing:

import os
import sys
sys.path.insert(0,os.path.dirname(os.path.realpath(__file__)) + "/relative/path/to/code/")

This will add the folder of interest to the python path without modifying every test file, setting env variable or messing with absolute/relative paths.

Show special characters in Unix while using 'less' Command

You can do that with cat and that pipe the output to less:

cat -e yourFile | less

This excerpt from man cat explains what -e means:

   -e     equivalent to -vE

   -E, --show-ends
          display $ at end of each line

   -v, --show-nonprinting
          use ^ and M- notation, except for LFD and TAB

How can I wait for a thread to finish with .NET?

The previous two answers are great and will work for simple scenarios. There are other ways to synchronize threads, however. The following will also work:

public void StartTheActions()
{
    ManualResetEvent syncEvent = new ManualResetEvent(false);

    Thread t1 = new Thread(
        () =>
        {
            // Do some work...
            syncEvent.Set();
        }
    );
    t1.Start();

    Thread t2 = new Thread(
        () =>
        {
            syncEvent.WaitOne();

            // Do some work...
        }
    );
    t2.Start();
}

ManualResetEvent is one of the various WaitHandle's that the .NET framework has to offer. They can provide much richer thread synchronization capabilities than the simple, but very common tools like lock()/Monitor, Thread.Join, etc.

They can also be used to synchronize more than two threads, allowing complex scenarios such as a 'master' thread that coordinates multiple 'child' threads, multiple concurrent processes that are dependent upon several stages of each other to be synchronized, etc.

What's the difference between git reset --mixed, --soft, and --hard?

All the other answers are great, but I find it best to understand them by breaking down files into three categories: unstaged, staged, commit:

  • --hard should be easy to understand, it restores everything
  • --mixed (default) :
    1. unstaged files: don't change
    2. staged files: move to unstaged
    3. commit files: move to unstaged
  • --soft:
    1. unstaged files: don't change
    2. staged files: dont' change
    3. commit files: move to staged

In summary:

  • --soft option will move everything (except unstaged files) into staging area
  • --mixed option will move everything into unstaged area

Specify multiple attribute selectors in CSS

For concatenating it's:

input[name="Sex"][value="M"] {}

And for taking union it's:

input[name="Sex"], input[value="M"] {}

What is the difference between “int” and “uint” / “long” and “ulong”?

The difference is that the uint and ulong are unsigned data types, meaning the range is different: They do not accept negative values:

int range: -2,147,483,648 to 2,147,483,647
uint range: 0 to 4,294,967,295

long range: –9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
ulong range: 0 to 18,446,744,073,709,551,615

cartesian product in pandas

This won't win a code golf competition, and borrows from the previous answers - but clearly shows how the key is added, and how the join works. This creates 2 new data frames from lists, then adds the key to do the cartesian product on.

My use case was that I needed a list of all store IDs on for each week in my list. So, I created a list of all the weeks I wanted to have, then a list of all the store IDs I wanted to map them against.

The merge I chose left, but would be semantically the same as inner in this setup. You can see this in the documentation on merging, which states it does a Cartesian product if key combination appears more than once in both tables - which is what we set up.

days = pd.DataFrame({'date':list_of_days})
stores = pd.DataFrame({'store_id':list_of_stores})
stores['key'] = 0
days['key'] = 0
days_and_stores = days.merge(stores, how='left', on = 'key')
days_and_stores.drop('key',1, inplace=True)

Requery a subform from another form?

By closing and opening, the main form usually runs all related queries (including the subform related ones). I had a similar problem and resolved it by adding the following to Save Command button on click event.

DoCmd.Close acForm, "formname", acSaveYes
DoCmd.OpenForm "formname"

How can I remove a child node in HTML using JavaScript?

You have to remove any event handlers you've set on the node before you remove it, to avoid memory leaks in IE

Calling a Sub in VBA

For anyone still coming to this post, the other option is to simply omit the parentheses:

Sub SomeOtherSub(Stattyp As String)
    'Daty and the other variables are defined here

    CatSubProduktAreakum Stattyp, Daty + UBound(SubCategories) + 2

End Sub

The Call keywords is only really in VBA for backwards compatibilty and isn't actually required.

If however, you decide to use the Call keyword, then you have to change your syntax to suit.

'// With Call
Call Foo(Bar)

'// Without Call
Foo Bar

Both will do exactly the same thing.


That being said, there may be instances to watch out for where using parentheses unnecessarily will cause things to be evaluated where you didn't intend them to be (as parentheses do this in VBA) so with that in mind the better option is probably to omit the Call keyword and the parentheses

How to create Password Field in Model Django

You should create a ModelForm (docs), which has a field that uses the PasswordInput widget from the forms library.

It would look like this:

models.py

from django import models
class User(models.Model):
    username = models.CharField(max_length=100)
    password = models.CharField(max_length=50)

forms.py (not views.py)

from django import forms
class UserForm(forms.ModelForm):
    class Meta:
        model = User
        widgets = {
        'password': forms.PasswordInput(),
    }

For more about using forms in a view, see this section of the docs.

Apply CSS rules if browser is IE

I prefer using a separate file for ie rules, as described earlier.

<!--[if IE]><link rel="stylesheet" type="text/css" href="ie-style.css"/><![endif]-->

And inside it you can set up rules for different versions of ie using this:

.abc {...} /* ALL MSIE */
*html *.abc {...} /* MSIE 6 */
*:first-child+html .abc {...} /* MSIE 7 */

How to compare strings in C conditional preprocessor-directives

[UPDATE: 2021.01.04]

One thing that has changed since I first posted this in 2014, is the format of #pragma message.

Nowadays, the parens are required!

#pragma message ("USER    IS " USER)
#pragma message ("USER_VS IS " USER_VS)

That said, the 2016 code (using characters, not strings) still works in VS2019.

But, as @Artyer points out, the version involving c_strcmp will NOT work in ANY modern compiler.

[UPDATE: 2018.05.03]

CAVEAT: Not all compilers implement the C++11 specification in the same way. The below code works in the compiler I tested on, while many commenters used a different compiler.

Quoting from Shafik Yaghmour's answer at: Computing length of a C string at compile time. Is this really a constexpr?

Constant expressions are not guaranteed to be evaluated at compile time, we only have a non-normative quote from draft C++ standard section 5.19 Constant expressions that says this though:

[...]>[ Note: Constant expressions can be evaluated during translation.—end note ]

That word can makes all the difference in the world.

So, YMMV on this (or any) answer involving constexpr, depending on the compiler writer's interpretation of the spec.

[UPDATED 2016.01.31]

As some didn't like my earlier answer because it avoided the whole compile time string compare aspect of the OP by accomplishing the goal with no need for string compares, here is a more detailed answer.

You can't! Not in C98 or C99. Not even in C11. No amount of MACRO manipulation will change this.

The definition of const-expression used in the #if does not allow strings.

It does allow characters, so if you limit yourself to characters you might use this:

#define JACK 'J'
#define QUEEN 'Q'

#define CHOICE JACK     // or QUEEN, your choice

#if 'J' == CHOICE
#define USER "jack"
#define USER_VS "queen"
#elif 'Q' == CHOICE
#define USER "queen"
#define USER_VS "jack"
#else
#define USER "anonymous1"
#define USER_VS "anonymous2"
#endif

#pragma message "USER    IS " USER
#pragma message "USER_VS IS " USER_VS

You can! In C++11. If you define a compile time helper function for the comparison.

[2021.01.04: CAVEAT: This does not work in any MODERN compiler. See comment by @Artyer.]

// compares two strings in compile time constant fashion
constexpr int c_strcmp( char const* lhs, char const* rhs )
{
    return (('\0' == lhs[0]) && ('\0' == rhs[0])) ? 0
        :  (lhs[0] != rhs[0]) ? (lhs[0] - rhs[0])
        : c_strcmp( lhs+1, rhs+1 );
}
// some compilers may require ((int)lhs[0] - (int)rhs[0])

#define JACK "jack"
#define QUEEN "queen"

#define USER JACK       // or QUEEN, your choice

#if 0 == c_strcmp( USER, JACK )
#define USER_VS QUEEN
#elif 0 == c_strcmp( USER, QUEEN )
#define USER_VS JACK
#else
#define USER_VS "unknown"
#endif

#pragma message "USER    IS " USER
#pragma message "USER_VS IS " USER_VS

So, ultimately, you will have to change the way you accomlish your goal of choosing final string values for USER and USER_VS.

You can't do compile time string compares in C99, but you can do compile time choosing of strings.

If you really must do compile time sting comparisons, then you need to change to C++11 or newer variants that allow that feature.

[ORIGINAL ANSWER FOLLOWS]

Try:

#define jack_VS queen
#define queen_VS jack

#define USER jack          // jack    or queen, your choice
#define USER_VS USER##_VS  // jack_VS or queen_VS

// stringify usage: S(USER) or S(USER_VS) when you need the string form.
#define S(U) S_(U)
#define S_(U) #U

UPDATE: ANSI token pasting is sometimes less than obvious. ;-D

Putting a single # before a macro causes it to be changed into a string of its value, instead of its bare value.

Putting a double ## between two tokens causes them to be concatenated into a single token.

So, the macro USER_VS has the expansion jack_VS or queen_VS, depending on how you set USER.

The stringify macro S(...) uses macro indirection so the value of the named macro gets converted into a string. instead of the name of the macro.

Thus USER##_VS becomes jack_VS (or queen_VS), depending on how you set USER.

Later, when the stringify macro is used as S(USER_VS) the value of USER_VS (jack_VS in this example) is passed to the indirection step S_(jack_VS) which converts its value (queen) into a string "queen".

If you set USER to queen then the final result is the string "jack".

For token concatenation, see: https://gcc.gnu.org/onlinedocs/cpp/Concatenation.html

For token string conversion, see: https://gcc.gnu.org/onlinedocs/cpp/Stringification.html#Stringification

[UPDATED 2015.02.15 to correct a typo.]

How to read text file in JavaScript

This can be done quite easily using javascript XMLHttpRequest() class (AJAX):

function FileHelper()

{
    FileHelper.readStringFromFileAtPath = function(pathOfFileToReadFrom)
    {
        var request = new XMLHttpRequest();
        request.open("GET", pathOfFileToReadFrom, false);
        request.send(null);
        var returnValue = request.responseText;

        return returnValue;
    }
}

...

var text = FileHelper.readStringFromFileAtPath ( "mytext.txt" );

Display exact matches only with grep

Recently I came across an issue in grep. I was trying to match the pattern x.y.z and grep returned x.y-z.Using some regular expression we may can overcome this, but with grep whole word matching did not help. Since the script I was writing is a generic one, I cannot restrict search for a specific way as in like x.y.z or x.y-z ..

Quick way I figured is to run a grep and then a condition check var="x.y.z" var1=grep -o x.y.z file.txt if [ $var1 == $var ] echo "Pattern match exact" else echo "Pattern does not match exact" fi

https://linuxacatalyst.blogspot.com/2019/12/grep-pattern-matching-issues.html

How to convert date in to yyyy-MM-dd Format?

A date-time object is supposed to store the information about the date, time, timezone etc., not about the formatting. You can format a date-time object into a String with the pattern of your choice using date-time formatting API.

  • The date-time formatting API for the modern date-time types is in the package, java.time.format e.g. java.time.format.DateTimeFormatter, java.time.format.DateTimeFormatterBuilder etc.
  • The date-time formatting API for the legacy date-time types is in the package, java.text e.g. java.text.SimpleDateFormat, java.text.DateFormat etc.

Demo using modern API:

import java.time.LocalDate;
import java.time.Month;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;

public class Main {
    public static void main(String[] args) {
        ZonedDateTime zdt = ZonedDateTime.of(LocalDate.of(2012, Month.DECEMBER, 1).atStartOfDay(),
                ZoneId.of("Europe/London"));

        // Default format returned by Date#toString
        System.out.println(zdt);

        // Custom format
        DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd", Locale.ENGLISH);
        String formattedDate = dtf.format(zdt);
        System.out.println(formattedDate);
    }
}

Output:

2012-12-01T00:00Z[Europe/London]
2012-12-01

Learn about the modern date-time API from Trail: Date Time.

Demo using legacy API:

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;

public class Main {
    public static void main(String[] args) {
        Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
        calendar.setTimeInMillis(0);
        calendar.set(Calendar.YEAR, 2012);
        calendar.set(Calendar.MONTH, 11);
        calendar.set(Calendar.DAY_OF_MONTH, 1);
        Date date = calendar.getTime();

        // Default format returned by Date#toString
        System.out.println(date);

        // Custom format
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd", Locale.ENGLISH);
        String formattedDate = sdf.format(date);
        System.out.println(formattedDate);
    }
}

Output:

Sat Dec 01 00:00:00 GMT 2012
2012-12-01

Some more important points:

  1. The java.util.Date object is not a real date-time object like the modern date-time types; rather, it represents the milliseconds from the Epoch of January 1, 1970. When you print an object of java.util.Date, its toString method returns the date-time calculated from this milliseconds value. Since java.util.Date does not have timezone information, it applies the timezone of your JVM and displays the same. If you need to print the date-time in a different timezone, you will need to set the timezone to SimpleDateFomrat and obtain the formatted string from it.
  2. The date-time API of java.util and their formatting API, SimpleDateFormat are outdated and error-prone. It is recommended to stop using them completely and switch to the modern date-time API.

bootstrap initially collapsed element

If removing the in class doesn't work for you, such was my case, you can force the collapsed initial state using the CSS display property:

...
<div id="collapseOne" class="accordion-body collapse" style="display: none;">
...

How to change row color in datagridview?

Just a note about setting DefaultCellStyle.BackColor...you can't set it to any transparent value except Color.Empty. That's the default value. That falsely implies (to me, anyway) that transparent colors are OK. They're not. Every row I set to a transparent color just draws the color of selected-rows.

I spent entirely too much time beating my head against the wall over this issue.

How to add a ListView to a Column in Flutter?

Reason for the error:

Column expands to the maximum size in main axis direction (vertical axis), and so does the ListView.

Solutions

So, you need to constrain the height of the ListView. There are many ways of doing it, you can choose that best suits your need.


  1. If you want to allow ListView to take up all remaining space inside Column use Expanded.

    Column(
      children: <Widget>[
        Expanded(
          child: ListView(...),
        )
      ],
    )
    

  1. If you want to limit your ListView to certain height, you can use SizedBox.

    Column(
      children: <Widget>[
        SizedBox(
          height: 200, // constrain height
          child: ListView(),
        )
      ],
    )
    

  1. If your ListView is small, you may try shrinkWrap property on it.

    Column(
      children: <Widget>[
        ListView(
          shrinkWrap: true, // use it
        )
      ],
    )
    

ValueError: max() arg is an empty sequence

in one line,

v = max(v) if v else None

>>> v = []
>>> max(v)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: max() arg is an empty sequence
>>> v = max(v) if v else None
>>> v
>>> 

Build a basic Python iterator

Iterator objects in python conform to the iterator protocol, which basically means they provide two methods: __iter__() and __next__().

  • The __iter__ returns the iterator object and is implicitly called at the start of loops.

  • The __next__() method returns the next value and is implicitly called at each loop increment. This method raises a StopIteration exception when there are no more value to return, which is implicitly captured by looping constructs to stop iterating.

Here's a simple example of a counter:

class Counter:
    def __init__(self, low, high):
        self.current = low - 1
        self.high = high

    def __iter__(self):
        return self

    def __next__(self): # Python 2: def next(self)
        self.current += 1
        if self.current < self.high:
            return self.current
        raise StopIteration


for c in Counter(3, 9):
    print(c)

This will print:

3
4
5
6
7
8

This is easier to write using a generator, as covered in a previous answer:

def counter(low, high):
    current = low
    while current < high:
        yield current
        current += 1

for c in counter(3, 9):
    print(c)

The printed output will be the same. Under the hood, the generator object supports the iterator protocol and does something roughly similar to the class Counter.

David Mertz's article, Iterators and Simple Generators, is a pretty good introduction.

Python Requests and persistent sessions

Check out my answer in this similar question:

python: urllib2 how to send cookie with urlopen request

import urllib2
import urllib
from cookielib import CookieJar

cj = CookieJar()
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
# input-type values from the html form
formdata = { "username" : username, "password": password, "form-id" : "1234" }
data_encoded = urllib.urlencode(formdata)
response = opener.open("https://page.com/login.php", data_encoded)
content = response.read()

EDIT:

I see I've gotten a few downvotes for my answer, but no explaining comments. I'm guessing it's because I'm referring to the urllib libraries instead of requests. I do that because the OP asks for help with requests or for someone to suggest another approach.

List<T> or IList<T>

If you are exposing your class through a library that others will use, you generally want to expose it via interfaces rather than concrete implementations. This will help if you decide to change the implementation of your class later to use a different concrete class. In that case the users of your library won't need to update their code since the interface doesn't change.

If you are just using it internally, you may not care so much, and using List<T> may be ok.

Choose File Dialog

I have implemented the Samsung File Selector Dialog, it provides the ability to open, save file, file extension filter, and create new directory in the same dialog I think it worth trying Here is the Link you have to log in to Samsung developer site to view the solution

How to set a session variable when clicking a <a> link

Is your link to another web page? If so, perhaps you could put the variable in the query string and set the session variable when the page being linked to is loaded.

So the link looks like this:

<a href="home.php?variable=value" name="home">home</a>

And the homge page would parse the query string and set the session variable.

The Role Manager feature has not been enabled

If you got here because you're using the new ASP.NET Identity UserManager, what you're actually looking for is the RoleManager:

var roleManager = new RoleManager<IdentityRole>(new RoleStore<IdentityRole>(new ApplicationDbContext()));

roleManager will give you access to see if the role exists, create, etc, plus it is created for the UserManager

Hiding a form and showing another when a button is clicked in a Windows Forms application

Anything after Application.Run( ) will only be executed when the main form closes.

What you could do is handle the VisibleChanged event as follows:

static Form1 form1;
static Form2 form2;

static void Main()
{

    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    form2 = new Form2();
    form1 = new Form1();
    form2.Hide();
    form1.VisibleChanged += OnForm1Changed;
    Application.Run(form1);

}

static void OnForm1Changed( object sender, EventArgs args )
{
    if ( !form1.Visible )
    {
        form2.Show( );
    }
}

How to check the maximum number of allowed connections to an Oracle database?

The sessions parameter is derived from the processes parameter and changes accordingly when you change the number of max processes. See the Oracle docs for further info.

To get only the info about the sessions:

    select current_utilization, limit_value 
    from v$resource_limit 
    where resource_name='sessions';
CURRENT_UTILIZATION LIMIT_VALUE
------------------- -----------
                110         792

Try this to show info about both:

    select resource_name, current_utilization, max_utilization, limit_value 
    from v$resource_limit 
    where resource_name in ('sessions', 'processes');
RESOURCE_NAME CURRENT_UTILIZATION MAX_UTILIZATION LIMIT_VALUE
------------- ------------------- --------------- -----------
processes                      96             309         500
sessions                      104             323         792

Bootstrap 4, how to make a col have a height of 100%?

Although it is not a good solution but may solve your problem. You need to use position absolute in #yellow element!

_x000D_
_x000D_
#yellow {height: 100%; background: yellow; position: absolute; top: 0px; left: 0px;}_x000D_
.container-fluid {position: static !important;}
_x000D_
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" integrity="sha384-rwoIResjU2yc3z8GV/NPeZWAv56rSmLldC3R/AZzGRnGxQQKnKkoFVhFQhNUwEyJ" crossorigin="anonymous">_x000D_
<div class="container-fluid">_x000D_
  <div class="row justify-content-center">_x000D_
_x000D_
    <div class="col-4" id="yellow">_x000D_
      XXXX_x000D_
    </div>_x000D_
_x000D_
    <div class="col-10 col-sm-10 col-md-10 col-lg-8 col-xl-8">_x000D_
      Form Goes Here_x000D_
    </div>_x000D_
  </div>_x000D_
</div>_x000D_
<script src="https://code.jquery.com/jquery-3.1.1.slim.min.js" integrity="sha384-A7FZj7v+d/sdmMqp/nOQwliLvUsJfDHW+k9Omg/a/EheAdgtzNs3hpfag6Ed950n" crossorigin="anonymous"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/tether/1.4.0/js/tether.min.js" integrity="sha384-DztdAPBWPRXSA/3eYEEUWrWCy7G5KFbe8fFjk5JAIxUYHKkDx6Qin1DkWx51bBrb" crossorigin="anonymous"></script>_x000D_
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js" integrity="sha384-vBWWzlZJ8ea9aCX4pEW3rVHjgjt7zpkNpZk+02D9phzyeVkE+jo0ieGizqPLForn" crossorigin="anonymous"></script>
_x000D_
_x000D_
_x000D_

How can I detect browser type using jQuery?

Try to use it

$(document).ready(function() {
// If the browser type if Mozilla Firefox
if ($.browser.mozilla && $.browser.version >= "1.8" ){ 
// some code
}
// If the browser type is Opera
if( $.browser.opera)
{
// some code
}
// If the web browser type is Safari
if( $.browser.safari )
{
// some code
}
// If the web browser type is Chrome
if( $.browser.chrome)
{
// some code
}
// If the web browser type is Internet Explorer
if ($.browser.msie && $.browser.version <= 6 )
{
// some code
}
//If the web browser type is Internet Explorer 6 and above
if ($.browser.msie && $.browser.version > 6)
{
// some code
}
});

How to declare a type as nullable in TypeScript?

You can just implement a user-defined type like the following:

type Nullable<T> = T | undefined | null;

var foo: Nullable<number> = 10; // ok
var bar: Nullable<number> = true; // type 'true' is not assignable to type 'Nullable<number>'
var baz: Nullable<number> = null; // ok

var arr1: Nullable<Array<number>> = [1,2]; // ok
var obj: Nullable<Object> = {}; // ok

 // Type 'number[]' is not assignable to type 'string[]'. 
 // Type 'number' is not assignable to type 'string'
var arr2: Nullable<Array<string>> = [1,2];

opening a window form from another form programmatically

To open from with button click please add the following code in the button event handler

var m = new Form1();
m.Show();

Here Form1 is the name of the form which you want to open.

Also to close the current form, you may use

this.close();

Undefined Symbols error when integrating Apptentive iOS SDK via Cocoapods

We have found that adding the Apptentive cocoa pod to an existing Xcode project may potentially not include some of our required frameworks.

Check your linker flags:

Target > Build Settings > Other Linker Flags 

You should see -lApptentiveConnect listed as a linker flag:

... -ObjC -lApptentiveConnect ... 

You should also see our required Frameworks listed:

  • Accelerate
  • CoreData
  • CoreText
  • CoreGraphics
  • CoreTelephony
  • Foundation
  • QuartzCore
  • StoreKit
  • SystemConfiguration
  • UIKit

    -ObjC -lApptentiveConnect -framework Accelerate -framework CoreData -framework CoreGraphics -framework CoreText -framework Foundation -framework QuartzCore -framework SystemConfiguration -framework UIKit -framework CoreTelephony -framework StoreKit  

Why does LayoutInflater ignore the layout_width and layout_height layout parameters I've specified?

andig is correct that a common reason for LayoutInflater ignoring your layout_params would be because a root was not specified. Many people think you can pass in null for root. This is acceptable for a few scenarios such as a dialog, where you don't have access to root at the time of creation. A good rule to follow, however, is that if you have root, give it to LayoutInflater.

I wrote an in-depth blog post about this that you can check out here:

https://www.bignerdranch.com/blog/understanding-androids-layoutinflater-inflate/

What is the meaning of "$" sign in JavaScript

Basic syntax is: $(selector).action()

A dollar sign to define jQuery A (selector) to "query (or find)" HTML elements A jQuery action() to be performed on the element(s)

How do you install Boost on MacOS?

Fink appears to have a full set of Boost packages...

With fink installed and running just do

fink install boost1.35.nopython

at the terminal and accept the dependencies it insists on. Or use

fink list boost

to get a list of different packages that are availible.

Define preprocessor macro through CMake?

To do this for a specific target, you can do the following:

target_compile_definitions(my_target PRIVATE FOO=1 BAR=1)

You should do this if you have more than one target that you're building and you don't want them all to use the same flags. Also see the official documentation on target_compile_definitions.

How can I close a dropdown on click outside?

ELEGANT METHOD

I found this clickOut directive: https://github.com/chliebel/angular2-click-outside. I check it and it works well (i only copy clickOutside.directive.ts to my project). U can use it in this way:

<div (clickOutside)="close($event)"></div>

Where close is your function which will be call when user click outside div. It is very elegant way to handle problem described in question.

If you use above directive to close popUp window, remember first to add event.stopPropagation() to button click event handler which open popUp.

BONUS:

Below i copy oryginal directive code from file clickOutside.directive.ts (in case if link will stop working in future) - the author is Christian Liebel :

_x000D_
_x000D_
import {Directive, ElementRef, Output, EventEmitter, HostListener} from '@angular/core';_x000D_
    _x000D_
@Directive({_x000D_
    selector: '[clickOutside]'_x000D_
})_x000D_
export class ClickOutsideDirective {_x000D_
    constructor(private _elementRef: ElementRef) {_x000D_
    }_x000D_
_x000D_
    @Output()_x000D_
    public clickOutside = new EventEmitter<MouseEvent>();_x000D_
_x000D_
    @HostListener('document:click', ['$event', '$event.target'])_x000D_
    public onClick(event: MouseEvent, targetElement: HTMLElement): void {_x000D_
        if (!targetElement) {_x000D_
            return;_x000D_
        }_x000D_
_x000D_
        const clickedInside = this._elementRef.nativeElement.contains(targetElement);_x000D_
        if (!clickedInside) {_x000D_
            this.clickOutside.emit(event);_x000D_
        }_x000D_
    }_x000D_
}
_x000D_
_x000D_
_x000D_

Check if cookie exists else set cookie to Expire in 10 days

if (/(^|;)\s*visited=/.test(document.cookie)) {
    alert("Hello again!");
} else {
    document.cookie = "visited=true; max-age=" + 60 * 60 * 24 * 10; // 60 seconds to a minute, 60 minutes to an hour, 24 hours to a day, and 10 days.
    alert("This is your first time!");
}

is one way to do it. Note that document.cookie is a magic property, so you don't have to worry about overwriting anything, either.

There are also more convenient libraries to work with cookies, and if you don’t need the information you’re storing sent to the server on every request, HTML5’s localStorage and friends are convenient and useful.

List all indexes on ElasticSearch server?

I had Kibana and ES installed on a machine. But I did not know the details(at what path, or port) was the ES node on that machine.

So how can you do it from Kibana (version 5.6)?

  • Go to Dev Tools
  • See Console section, and run the following query:

GET _cat/indices

I was interested in finding the the size of a particular ES index

How to find and restore a deleted file in a Git repository

Actually, this question is directly about Git, but somebody like me works with GUI tools like the WebStorm VCS other than knowing about Git CLI commands.

I right click on the path that contains the deleted file, and then go to Git and then click on Show History.

Enter image description here

The VCS tools show all revisions train and I can see all commits and changes of each of them.

Enter image description here

Then I select the commits that my friend delete the PostAd.js file. now see below:

Enter image description here

And now, I can see my desire deleted file. I just double-click on the filename and it recovers.

Enter image description here

I know my answer is not Git commands, but it is fast, reliable and easy for beginner and professional developers. WebStorm VCS tools are awesome and perfect for working with Git and it doesn't need any other plugin or tools.

How to rename JSON key

If anyone needs to do this dynamically:

const keys = Object.keys(jsonObject);

keys.forEach((key) => {

      // CREATE A NEW KEY HERE
      var newKey = key.replace(' ', '_');

      jsonObject[newKey] = jsonObject[key];
      delete jsonObject[key];
   });

jsonObject will now have the new keys.

IMPORTANT:

If your key is not changed by the replace function, it will just take it out of the array. You may want to put some if statements in there.

One-line list comprehension: if-else variants

Just another solution, hope some one may like it :

Using: [False, True][Expression]

>>> map(lambda x: [x*100, x][x % 2 != 0], range(1,10))
[1, 200, 3, 400, 5, 600, 7, 800, 9]
>>>

Put quotes around a variable string in JavaScript

You can add these single quotes with template literals:

_x000D_
_x000D_
var text = "http://example.com"_x000D_
var quoteText = `'${text}'`_x000D_
_x000D_
console.log(quoteText)
_x000D_
_x000D_
_x000D_

Docs are here. Browsers that support template literals listed here.

PHP expects T_PAAMAYIM_NEKUDOTAYIM?

For me this happened within a class function.

In PHP 5.3 and above $this::$defaults worked fine; when I swapped the code into a server that for whatever reason had a lower version number it threw this error.

The solution, in my case, was to use the keyword self instead of $this:

self::$defaults works just fine.

Using css transform property in jQuery

If you're using jquery, jquery.transit is very simple and powerful lib that allows you to make your transformation while handling cross-browser compability for you. It can be as simple as this : $("#element").transition({x:'90px'}).

Take it from this link : http://ricostacruz.com/jquery.transit/

Can I call methods in constructor in Java?

Can I put my method readConfig() into constructor?

Invoking a not overridable method in a constructor is an acceptable approach.
While if the method is only used by the constructor you may wonder if extracting it into a method (even private) is really required.

If you choose to extract some logic done by the constructor into a method, as for any method you have to choose a access modifier that fits to the method requirement but in this specific case it matters further as protecting the method against the overriding of the method has to be done at risk of making the super class constructor inconsistent.

So it should be private if it is used only by the constructor(s) (and instance methods) of the class.
Otherwise it should be both package-private and final if the method is reused inside the package or in the subclasses.

which would give me benefit of one time calling or is there another mechanism to do that ?

You don't have any benefit or drawback to use this way.
I don't encourage to perform much logic in constructors but in some cases it may make sense to init multiple things in a constructor.
For example the copy constructor may perform a lot of things.
Multiple JDK classes illustrate that.
Take for example the HashMap copy constructor that constructs a new HashMap with the same mappings as the specified Map parameter :

public HashMap(Map<? extends K, ? extends V> m) {
    this.loadFactor = DEFAULT_LOAD_FACTOR;
    putMapEntries(m, false);
}

final void putMapEntries(Map<? extends K, ? extends V> m, boolean evict) {
    int s = m.size();
    if (s > 0) {
        if (table == null) { // pre-size
            float ft = ((float)s / loadFactor) + 1.0F;
            int t = ((ft < (float)MAXIMUM_CAPACITY) ?
                     (int)ft : MAXIMUM_CAPACITY);
            if (t > threshold)
                threshold = tableSizeFor(t);
        }
        else if (s > threshold)
            resize();
        for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
            K key = e.getKey();
            V value = e.getValue();
            putVal(hash(key), key, value, false, evict);
        }
    }
}

Extracting the logic of the map populating in putMapEntries() is a good thing because it allows :

  • reusing the method in other contexts. For example clone() and putAll() use it too
  • (minor but interesting) giving a meaningful name that conveys the performed logic

Asyncio.gather vs asyncio.wait

A very important distinction, which is easy to miss, is the default bheavior of these two functions, when it comes to exceptions.


I'll use this example to simulate a coroutine that will raise exceptions, sometimes -

import asyncio
import random


async def a_flaky_tsk(i):
    await asyncio.sleep(i)  # bit of fuzz to simulate a real-world example

    if i % 2 == 0:
        print(i, "ok")
    else:
        print(i, "crashed!")
        raise ValueError

coros = [a_flaky_tsk(i) for i in range(10)]

await asyncio.gather(*coros) outputs -

0 ok
1 crashed!
Traceback (most recent call last):
  File "/Users/dev/PycharmProjects/trading/xxx.py", line 20, in <module>
    asyncio.run(main())
  File "/Users/dev/.pyenv/versions/3.8.2/lib/python3.8/asyncio/runners.py", line 43, in run
    return loop.run_until_complete(main)
  File "/Users/dev/.pyenv/versions/3.8.2/lib/python3.8/asyncio/base_events.py", line 616, in run_until_complete
    return future.result()
  File "/Users/dev/PycharmProjects/trading/xxx.py", line 17, in main
    await asyncio.gather(*coros)
  File "/Users/dev/PycharmProjects/trading/xxx.py", line 12, in a_flaky_tsk
    raise ValueError
ValueError

As you can see, the coros after index 1 never got to execute.


But await asyncio.wait(coros) continues to execute tasks, even if some of them fail -

0 ok
1 crashed!
2 ok
3 crashed!
4 ok
5 crashed!
6 ok
7 crashed!
8 ok
9 crashed!
Task exception was never retrieved
future: <Task finished name='Task-10' coro=<a_flaky_tsk() done, defined at /Users/dev/PycharmProjects/trading/xxx.py:6> exception=ValueError()>
Traceback (most recent call last):
  File "/Users/dev/PycharmProjects/trading/xxx.py", line 12, in a_flaky_tsk
    raise ValueError
ValueError
Task exception was never retrieved
future: <Task finished name='Task-8' coro=<a_flaky_tsk() done, defined at /Users/dev/PycharmProjects/trading/xxx.py:6> exception=ValueError()>
Traceback (most recent call last):
  File "/Users/dev/PycharmProjects/trading/xxx.py", line 12, in a_flaky_tsk
    raise ValueError
ValueError
Task exception was never retrieved
future: <Task finished name='Task-2' coro=<a_flaky_tsk() done, defined at /Users/dev/PycharmProjects/trading/xxx.py:6> exception=ValueError()>
Traceback (most recent call last):
  File "/Users/dev/PycharmProjects/trading/xxx.py", line 12, in a_flaky_tsk
    raise ValueError
ValueError
Task exception was never retrieved
future: <Task finished name='Task-9' coro=<a_flaky_tsk() done, defined at /Users/dev/PycharmProjects/trading/xxx.py:6> exception=ValueError()>
Traceback (most recent call last):
  File "/Users/dev/PycharmProjects/trading/xxx.py", line 12, in a_flaky_tsk
    raise ValueError
ValueError
Task exception was never retrieved
future: <Task finished name='Task-3' coro=<a_flaky_tsk() done, defined at /Users/dev/PycharmProjects/trading/xxx.py:6> exception=ValueError()>
Traceback (most recent call last):
  File "/Users/dev/PycharmProjects/trading/xxx.py", line 12, in a_flaky_tsk
    raise ValueError
ValueError

Ofcourse, this behavior can be changed for both by using -

asyncio.gather(..., return_exceptions=True)

or,

asyncio.wait([...], return_when=asyncio.FIRST_EXCEPTION)


But it doesn't end here!

Notice: Task exception was never retrieved in the logs above.

asyncio.wait() won't re-raise exceptions from the child tasks until you await them individually. (The stacktrace in the logs are just messages, they cannot be caught!)

done, pending = await asyncio.wait(coros)
for tsk in done:
    try:
        await tsk
    except Exception as e:
        print("I caught:", repr(e))

Output -

0 ok
1 crashed!
2 ok
3 crashed!
4 ok
5 crashed!
6 ok
7 crashed!
8 ok
9 crashed!
I caught: ValueError()
I caught: ValueError()
I caught: ValueError()
I caught: ValueError()
I caught: ValueError()

On the other hand, to catch exceptions with asyncio.gather(), you must -

results = await asyncio.gather(*coros, return_exceptions=True)
for result_or_exc in results:
    if isinstance(result_or_exc, Exception):
        print("I caught:", repr(result_or_exc))

(Same output as before)

How do I update a model value in JavaScript in a Razor view?

You could use jQuery and an Ajax call to post the specific update back to your server with Javascript.

It would look something like this:

function updatePostID(val, comment)
{

    var args = {};
    args.PostID = val;
    args.Comment = comment;

    $.ajax({
     type: "POST",
     url: controllerActionMethodUrlHere,
     contentType: "application/json; charset=utf-8",
     data: args,
     dataType: "json",
     success: function(msg) 
     {
        // Something afterwards here

     }
    });

}

How to write to error log file in PHP

We all know that PHP save errors in php_errors.log file.

But, that file contains a lot of data.

If we want to log our application data, we need to save it to a custom location.

We can use two parameters in the error_log function to achieve this.

http://php.net/manual/en/function.error-log.php

We can do it using:

error_log(print_r($v, TRUE), 3, '/var/tmp/errors.log');

Where,

print_r($v, TRUE) : logs $v (array/string/object) to log file. 3: Put log message to custom log file specified in the third parameter.

'/var/tmp/errors.log': Custom log file (This path is for Linux, we can specify other depending upon OS).

OR, you can use file_put_contents()

file_put_contents('/var/tmp/e.log', print_r($v, true), FILE_APPEND);

Where:

'/var/tmp/errors.log': Custom log file (This path is for Linux, we can specify other depending upon OS). print_r($v, TRUE) : logs $v (array/string/object) to log file. FILE_APPEND: Constant parameter specifying whether to append to the file if it exists, if file does not exist, new file will be created.

Difference between thread's context class loader and normal classloader

There is an article on javaworld.com that explains the difference => Which ClassLoader should you use

(1)

Thread context classloaders provide a back door around the classloading delegation scheme.

Take JNDI for instance: its guts are implemented by bootstrap classes in rt.jar (starting with J2SE 1.3), but these core JNDI classes may load JNDI providers implemented by independent vendors and potentially deployed in the application's -classpath. This scenario calls for a parent classloader (the primordial one in this case) to load a class visible to one of its child classloaders (the system one, for example). Normal J2SE delegation does not work, and the workaround is to make the core JNDI classes use thread context loaders, thus effectively "tunneling" through the classloader hierarchy in the direction opposite to the proper delegation.

(2) from the same source:

This confusion will probably stay with Java for some time. Take any J2SE API with dynamic resource loading of any kind and try to guess which loading strategy it uses. Here is a sampling:

  • JNDI uses context classloaders
  • Class.getResource() and Class.forName() use the current classloader
  • JAXP uses context classloaders (as of J2SE 1.4)
  • java.util.ResourceBundle uses the caller's current classloader
  • URL protocol handlers specified via java.protocol.handler.pkgs system property are looked up in the bootstrap and system classloaders only
  • Java Serialization API uses the caller's current classloader by default

Beginner Python: AttributeError: 'list' object has no attribute

Consider:

class Bike(object):
    def __init__(self, name, weight, cost):
        self.name = name
        self.weight = weight
        self.cost = cost

bikes = {
    # Bike designed for children"
    "Trike": Bike("Trike", 20, 100),      # <--
    # Bike designed for everyone"
    "Kruzer": Bike("Kruzer", 50, 165),    # <--
    }

# Markup of 20% on all sales
margin = .2
# Revenue minus cost after sale
for bike in bikes.values():
    profit = bike.cost * margin
    print(profit)

Output:

33.0
20.0

The difference is that in your bikes dictionary, you're initializing the values as lists [...]. Instead, it looks like the rest of your code wants Bike instances. So create Bike instances: Bike(...).

As for your error

AttributeError: 'list' object has no attribute 'cost'

this will occur when you try to call .cost on a list object. Pretty straightforward, but we can figure out what happened by looking at where you call .cost -- in this line:

profit = bike.cost * margin

This indicates that at least one bike (that is, a member of bikes.values() is a list). If you look at where you defined bikes you can see that the values were, in fact, lists. So this error makes sense.

But since your class has a cost attribute, it looked like you were trying to use Bike instances as values, so I made that little change:

[...] -> Bike(...)

and you're all set.

Convert JSON String To C# Object

Copy your Json and paste at textbox on json2csharp and click on Generate button.

A cs class will be generated use that cs file as below

var generatedcsResponce = JsonConvert.DeserializeObject(yourJson);

Where RootObject is the name of the generated cs file;

php foreach with multidimensional array

This would have been a comment under Brad's answer, but I don't have a high enough reputation.

Recently I found that I needed the key of the multidimensional array too, i.e., it wasn't just an index for the array, in the foreach loop.

In order to achieve that, you could use something very similar to the accepted answer, but instead split the key and value as follows

foreach ($mda as $mdaKey => $mdaData) {
    echo $mdaKey . ": " . $mdaData["value"];
}

Hope that helps someone.

Getting Java version at runtime

Just a note that in Java 9 and above, the naming convention is different. System.getProperty("java.version") returns "9" rather than "1.9".

How to change the new TabLayout indicator color and height

Foto indicator use this:

 tabLayout.setSelectedTabIndicatorColor(ContextCompat.getColor(this, R.color.colorWhite));//put your color

Replace all occurrences of a string in a data frame

late to the party. but if you only want to get rid of leading/trailing white space, R base has a function trimws

For example:

data <- apply(X = data, MARGIN = 2, FUN = trimws) %>% as.data.frame()

What is the purpose of a plus symbol before a variable?

Operator + is a unary operator which converts value to number. Below I prepared a table with corresponding results of using this operator for different values.

+-----------------------------+-----------+
| Value                       | + (Value) |
+-----------------------------+-----------+
| 1                           | 1         |
| '-1'                        | -1        |
| '3.14'                      | 3.14      |
| '3'                         | 3         |
| '0xAA'                      | 170       |
| true                        | 1         |
| false                       | 0         |
| null                        | 0         |
| 'Infinity'                  | Infinity  |
| 'infinity'                  | NaN       |
| '10a'                       | NaN       |
| undefined                   | Nan       |
| ['Apple']                   | Nan       |
| function(val){ return val } | NaN       |
+-----------------------------+-----------+

Operator + returns value for objects which have implemented method valueOf.

let something = {
    valueOf: function () {
        return 25;
    }
};

console.log(+something);

How to convert timestamps to dates in Bash?

I use this cross-platform one-liner:

date -d @1267619929 2>/dev/null || date -r 1267619929

It should work in both macOS and later versions of popular Linux distributions.

MySQL: How to set the Primary Key on phpMyAdmin?

MySQL can index the first x characters of a column,but a TEXT type is of variable length so mysql cant assure the uniqueness of the column.If you still want text column,use VARCHAR.

Multiple contexts with the same path error running web service in Eclipse using Tomcat

This error occurs when you copy a project than past it, and then you change the name of that project.

in such a case, follow the following steps.

Step-1: you need to edit your web.xml file. remove servlet and servlet-mapping of the previous projects.

Step-2: got to SERVER--> server.xml--> find context

Example :- Context docBase="JSPandServletDemo" path="/JSPandServletDemo" reloadable="true" source="org.eclipse.jst.jee.server:JSPandServletDemo"/>

now you just need to change the pathname to your current project name.

Good Luck Happy Coding :)

How to capture multiple repeated groups?

After reading Byte Commander's answer, I want to introduce a tiny possible improvement:

You can generate a regexp that will match either n words, as long as your n is predetermined. For instance, if I want to match between 1 and 3 words, the regexp:

^([A-Z]+)(?:,([A-Z]+))?(?:,([A-Z]+))?$

will match the next sentences, with one, two or three capturing groups.

HELLO,LITTLE,WORLD
HELLO,WORLD
HELLO

You can see a fully detailed explanation about this regular expression on Regex101.

As I said, it is pretty easy to generate this regexp for any groups you want using your favorite language. Since I'm not much of a swift guy, here's a ruby example:

def make_regexp(group_regexp, count: 3, delimiter: ",")
  regexp_str = "^(#{group_regexp})"
  (count - 1).times.each do
    regexp_str += "(?:#{delimiter}(#{group_regexp}))?"
  end
  regexp_str += "$"
  return regexp_str
end

puts make_regexp("[A-Z]+")

That being said, I'd suggest not using regular expression in that case, there are many other great tools from a simple split to some tokenization patterns depending on your needs. IMHO, a regular expression is not one of them. For instance in ruby I'd use something like str.split(",") or str.scan(/[A-Z]+/)

'setInterval' vs 'setTimeout'

setTimeout(expression, timeout); runs the code/function once after the timeout.

setInterval(expression, timeout); runs the code/function in intervals, with the length of the timeout between them.

Example:

var intervalID = setInterval(alert, 1000); // Will alert every second.
// clearInterval(intervalID); // Will clear the timer.

setTimeout(alert, 1000); // Will alert once, after a second.

Why is Dictionary preferred over Hashtable in C#?

In .NET, the difference between Dictionary<,> and HashTable is primarily that the former is a generic type, so you get all the benefits of generics in terms of static type checking (and reduced boxing, but this isn't as big as people tend to think in terms of performance - there is a definite memory cost to boxing, though).

Can't get private key with openssl (no start line:pem_lib.c:703:Expecting: ANY PRIVATE KEY)

My two cents: came across the same error message in RHEL7.3 while running the openssl command with root CA certificate. The reason being, while downloading the certificate from AD server, Encoding was selected as DER instead of Base64. Once the proper version of encoding was selected for the new certificate download, error was resolved

Hope this helps for new users :-)

Difference between binary tree and binary search tree

A binary search tree is a special kind of binary tree which exhibits the following property: for any node n, every descendant node's value in the left subtree of n is less than the value of n, and every descendant node's value in the right subtree is greater than the value of n.

Is there a way to access the "previous row" value in a SELECT statement?

The selected answer will only work if there are no gaps in the sequence. However if you are using an autogenerated id, there are likely to be gaps in the sequence due to inserts that were rolled back.

This method should work if you have gaps

declare @temp (value int, primaryKey int, tempid int identity)
insert value, primarykey from mytable order by  primarykey

select t1.value - t2.value from @temp  t1
join @temp  t2 
on t1.tempid = t2.tempid - 1

How to use lodash to find and return an object from Array?

Fetch id basing on name

 {
    "roles": [
     {
      "id": 1,
      "name": "admin",
     },
     {
      "id": 3,
      "name": "manager",
     }
    ]
    }



    fetchIdBasingOnRole() {
          const self = this;
          if (this.employee.roles) {
            var roleid = _.result(
              _.find(this.getRoles, function(obj) {
                return obj.name === self.employee.roles;
              }),
              "id"
            );
          }
          return roleid;
        },

How do I check in python if an element of a list is empty?

Just check if that element is equal to None type or make use of NOT operator ,which is equivalent to the NULL type you observe in other languages.

if not A[i]:
    ## do whatever

Anyway if you know the size of your list then you don't need to do all this.

How to prune local tracking branches that do not exist on remote anymore

I wanted something that would purge all local branches that were tracking a remote branch, on origin, where the remote branch has been deleted (gone). I did not want to delete local branches that were never set up to track a remote branch (i.e.: my local dev branches). Also, I wanted a simple one-liner that just uses git, or other simple CLI tools, rather than writing custom scripts. I ended up using a bit of grep and awk to make this simple command, then added it as an alias in my ~/.gitconfig.

[alias]
  prune-branches = !git remote prune origin && git branch -vv | grep ': gone]' | awk '{print $1}' | xargs -r git branch -D

Here is a git config --global ... command for easily adding this as git prune-branches:

git config --global alias.prune-branches '!git remote prune origin && git branch -vv | grep '"'"': gone]'"'"' | awk '"'"'{print $1}'"'"' | xargs -r git branch -d'

NOTE: Use of the -D flag to git branch can be very dangerous. So, in the config command above I use the -d option to git branch rather than -D; I use -D in my actual config. I use -D because I don't want to hear Git complain about unmerged branches, I just want them to go away. You may want this functionality as well. If so, simply use -D instead of -d at the end of that config command.

Cloning specific branch

I don't think you fully understand how git by default gives you all history of all branches.

git clone --branch master <URL> will give you what you want.

But in fact, in any of the other repos where you ended up with test_1 checked out, you could have just done git checkout master and it would have switched you to the master branch.

(What @CodeWizard says is all true, I just think it's more advanced than what you really need.)

How can I make a float top with CSS?

Hugogi Raudel has came up with an interesting way to to achieve this by CSS. suppose here is our HTML markup:

<ul>
  <li>1</li>
  <li>2</li>
  <li>3</li>
  <li>4</li>
  <li>5</li> 
  <li>6</li>
  <li>7</li>
  <li>8</li>
  <li>9</li>
</ul>

You can achieve a 3-row column using this CSS code:

li:nth-child(3n+2){
  margin: 120px 0 0 -110px;
}

li:nth-child(3n+3) {
  margin: 230px 0 0 -110px;
}

And here is the end result:
enter image description here
What we are doing here is adding a appropriate margin for each item in the row. This approach limitation is that you have to determine the column row count. it's not going to be dynamic. I'm sure it has use cases so I included this solution here.

Using Default Arguments in a Function

<?php
function info($name="George",$age=18) {
echo "$name is $age years old.<br>";
}
info();     // prints default values(number of values = 2)
info("Nick");   // changes first default argument from George to Nick
info("Mark",17);    // changes both default arguments' values

?>

SQLDataReader Row Count

Maybe you can try this: though please note - This pulls the column count, not the row count

 using (SqlDataReader reader = command.ExecuteReader())
 {
     while (reader.Read())
     {
         int count = reader.VisibleFieldCount;
         Console.WriteLine(count);
     }
 }

Where is Java's Array indexOf?

Array has no indexOf() method.

Maybe this Apache Commons Lang ArrayUtils method is what you are looking for

import org.apache.commons.lang3.ArrayUtils;

String[] colours = { "Red", "Orange", "Yellow", "Green" };

int indexOfYellow = ArrayUtils.indexOf(colours, "Yellow");

Search for an item in a Lua list

Use the following representation instead:

local items = { apple=true, orange=true, pear=true, banana=true }
if items.apple then
    ...
end

How can I format the output of a bash command in neat columns

Since AIX doesn't have a "column" command, I created the simplistic script below. It would be even shorter without the doc & input edits... :)

#!/usr/bin/perl
#       column.pl: convert STDIN to multiple columns on STDOUT
#       Usage: column.pl column-width number-of-columns  file...
#
$width = shift;
($width ne '') or die "must give column-width and number-of-columns\n";
$columns = shift;
($columns ne '') or die "must give number-of-columns\n";
($x = $width) =~ s/[^0-9]//g;
($x eq $width) or die "invalid column-width: $width\n";
($x = $columns) =~ s/[^0-9]//g;
($x eq $columns) or die "invalid number-of-columns: $columns\n";

$w = $width * -1; $c = $columns;
while (<>) {
        chomp;
        if ( $c-- > 1 ) {
                printf "%${w}s", $_;
                next;
        }
        $c = $columns;
        printf "%${w}s\n", $_;
}
print "\n";

bash: pip: command not found

Do following:

sudo apt update
sudo apt install python3-pip
source ~/.bashrc

This will surely install pip with all its dependencies. PS this is for python 3 if you want for python 2 replace python3 from the second command to python

sudo apt install python-pip

Best way to remove duplicate entries from a data table

In order to distinct all datatable columns, you can easily retrieve the names of the columns in a string array

public static DataTable RemoveDuplicateRows(this DataTable dataTable)
{
    List<string> columnNames = new List<string>();
    foreach (DataColumn col in dataTable.Columns)
    {
        columnNames.Add(col.ColumnName);
    }
    return dataTable.DefaultView.ToTable(true, columnNames.Select(c => c.ToString()).ToArray());
}

As you can notice, I thought of using it as an extension to DataTable class

C# - Insert a variable number of spaces into a string? (Formatting an output file)

Use String.Format:

string title1 = "Sample Title One";
string element1 = "Element One";
string format = "{0,-20} {1,-10}";

string result = string.Format(format, title1, element1);
//or you can print to Console directly with
//Console.WriteLine(format, title1, element1);

In the format {0,-20} means the first argument has a fixed length 20, and the negative sign guarantees the string is printed from left to right.

Maven not found in Mac OSX mavericks

Maven is not installed any more by default on Mac OS X 10.9. You need to install it yourself, for example using Homebrew.

The command to install Maven using Homebrew is brew install maven

Difference between volatile and synchronized in Java

volatile is a field modifier, while synchronized modifies code blocks and methods. So we can specify three variations of a simple accessor using those two keywords:

    int i1;
    int geti1() {return i1;}

    volatile int i2;
    int geti2() {return i2;}

    int i3;
    synchronized int geti3() {return i3;}

geti1() accesses the value currently stored in i1 in the current thread. Threads can have local copies of variables, and the data does not have to be the same as the data held in other threads.In particular, another thread may have updated i1 in it's thread, but the value in the current thread could be different from that updated value. In fact Java has the idea of a "main" memory, and this is the memory that holds the current "correct" value for variables. Threads can have their own copy of data for variables, and the thread copy can be different from the "main" memory. So in fact, it is possible for the "main" memory to have a value of 1 for i1, for thread1 to have a value of 2 for i1 and for thread2 to have a value of 3 for i1 if thread1 and thread2 have both updated i1 but those updated value has not yet been propagated to "main" memory or other threads.

On the other hand, geti2() effectively accesses the value of i2 from "main" memory. A volatile variable is not allowed to have a local copy of a variable that is different from the value currently held in "main" memory. Effectively, a variable declared volatile must have it's data synchronized across all threads, so that whenever you access or update the variable in any thread, all other threads immediately see the same value. Generally volatile variables have a higher access and update overhead than "plain" variables. Generally threads are allowed to have their own copy of data is for better efficiency.

There are two differences between volitile and synchronized.

Firstly synchronized obtains and releases locks on monitors which can force only one thread at a time to execute a code block. That's the fairly well known aspect to synchronized. But synchronized also synchronizes memory. In fact synchronized synchronizes the whole of thread memory with "main" memory. So executing geti3() does the following:

  1. The thread acquires the lock on the monitor for object this .
  2. The thread memory flushes all its variables, i.e. it has all of its variables effectively read from "main" memory .
  3. The code block is executed (in this case setting the return value to the current value of i3, which may have just been reset from "main" memory).
  4. (Any changes to variables would normally now be written out to "main" memory, but for geti3() we have no changes.)
  5. The thread releases the lock on the monitor for object this.

So where volatile only synchronizes the value of one variable between thread memory and "main" memory, synchronized synchronizes the value of all variables between thread memory and "main" memory, and locks and releases a monitor to boot. Clearly synchronized is likely to have more overhead than volatile.

http://javaexp.blogspot.com/2007/12/difference-between-volatile-and.html

Randomize a List<T>

You can achieve that be using this simple extension method

public static class IEnumerableExtensions
{

    public static IEnumerable<t> Randomize<t>(this IEnumerable<t> target)
    {
        Random r = new Random();

        return target.OrderBy(x=>(r.Next()));
    }        
}

and you can use it by doing the following

// use this on any collection that implements IEnumerable!
// List, Array, HashSet, Collection, etc

List<string> myList = new List<string> { "hello", "random", "world", "foo", "bar", "bat", "baz" };

foreach (string s in myList.Randomize())
{
    Console.WriteLine(s);
}

How to open a web page from my application?

Accepted answer no longer works on .NET Core 3. To make it work, use the following method:

var psi = new ProcessStartInfo
{
    FileName = url,
    UseShellExecute = true
};
Process.Start (psi);

How do I pass an object to HttpClient.PostAsync and serialize as a JSON body?

New .NET 5 Solution:

In .NET 5, a new class has been introduced called JsonContent, which derives from HttpContent. See in Microsoft docs

This class has a static method called Create(), which takes an object as a parameter.

Usage:

var myObject = new
{
    foo = "Hello",
    bar = "World",
};

JsonContent content = JsonContent.Create(myObject);

HttpResponseMessage response = await _httpClient.PostAsync("https://...", content);

Add space between two particular <td>s

td:nth-of-type(n) { padding-right: 10px;}

it will adjust auto space between all td

How to add directory to classpath in an application run profile in IntelliJ IDEA?

You can try -Xbootclasspath/a:path option of java application launcher. By description it specifies "a colon-separated path of directires, JAR archives, and ZIP archives to append to the default bootstrap class path."

Which MIME type to use for a binary file that's specific to my program?

According to the spec RFC 2045 #Syntax of the Content-Type Header Field application/myappname is not allowed, but application/x-myappname is allowed and sounds most appropriate for you're application to me.

How to increase heap size of an android application?

you can't increase the heap size dynamically.

you can request to use more by using android:largeHeap="true" in the manifest.

also, you can use native memory (NDK & JNI) , so you actually bypass the heap size limitation.

here are some posts i've made about it:

and here's a library i've made for it:

Java program to get the current date without timestamp

You can get by this date:

DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
print(dateFormat.format(new Date());

How to create a session using JavaScript?

You can use the name attr:

<script type="text/javascript" >
{
window.name ="This is my session";
}
</script> 

You still have to develop for yourself the format to use, or use a wrapper from an already existing library (mootools, Dojo etc).
You can also use cookies, but they are more heavy on performance, as they go back and forth from the client to the server, and are specific to one domain.

Properties file in python (similar to Java Properties)

My Java ini files didn't have section headers and I wanted a dict as a result. So i simply injected an "[ini]" section and let the default config library do its job. The result is converted to a dict:

from configparser import ConfigParser

@staticmethod
    def readPropertyFile(path):
        # https://stackoverflow.com/questions/3595363/properties-file-in-python-similar-to-java-properties
        config = ConfigParser()
        s_config= open(path, 'r').read()
        s_config="[ini]\n%s" % s_config
        # https://stackoverflow.com/a/36841741/1497139
        config.read_string(s_config)
        items=config.items('ini')
        itemDict={}
        for key,value in items:
            itemDict[key]=value
        return itemDict

How to remove a web site from google analytics

UPDATED ANSWER

Google Analytics Admin panel has 3 panels, wherein deleting can be done on any of the following :

  1. Account (Contains multiple properties, and views)
  2. Properties (Contains Views, a subset of Account)
  3. Views (subset of properties)

Google Analytics Admin Panel


Deleting an Account

Deleting the account, will remove all data pertaining to that account, along with all properties/profiles it contains. This is (usually) as good as removing the entire website data.

To delete the account, follow the following steps : (refer to image below)

  • Choose the account you want to delete.

Choose the account you want to delete

  • Click on Account Settings

Click Account Settings

  • Bottom right, a small link that says delete this account.

Delete account

  • You will get a confirmation, if you are sure to, click Delete Account
  • It will give you details, and will confirm deletion (and provide additional info like to remove GA snippet on your website, etc)

Note : If you have multiple accounts linked with your login, the other accounts are NOT touched, only this account will be deleted.


Deleting a property

Deleting a property will remove the selected property, and all the views it holds. To delete a property, delete all views it contains individually (see below for deleting views)

  • Choose the property

Property choice

  • All profiles related to that property appear on the right
  • Delete all the views related to the property individually (details in next section).

Deleting a View (profile)

Deleting a profile will remove only data pertaining to that view, if there is a single profile, the property is automatically deleted.

  • Choose the profile you want to delete

Choose profile

  • Click View Settings

Settings

  • Click on delete View (Bottom right)

Delete the view

  • Click Confirm, and that view will be deleted. If there is only a single view in the property, that property gets automatically deleted.

I want to keep the data, but not see them in the list

Sometimes you have a lot of websites, which you want to keep the data, but remove them from the list, since you don't view them often. I thought of a workaround, in case you do not want to delete the data.

Use another account.

  1. Say, your primary account is A, and you make another account B.
  2. Make B an administrator from A
  3. Remove A

Since A was your primary account, you no longer will be able to access it from the list!
And you still have your data saved, just that you'll have to log in via the other (spare) account.


Previous Answer :

These are the steps to delete a profile from Google Support page :

Delete profiles

Remember, too, that when you delete a profile, you also delete all data associated with that profile, and it is not possible to retrieve that deleted data.

To delete a profile:

  1. Click the Admin tab at the top right of any Analytics page.
  2. Click the account that contains the profile you want to delete.
  3. Click the web property from which you want to delete the profile.
  4. Use the Profile menu to select the profile.
  5. Click the Profile Settings tab.
  6. Click Delete this profile at the bottom of the page.
  7. Click Delete in the confirmation message.

Dynamic SQL - EXEC(@SQL) versus EXEC SP_EXECUTESQL(@SQL)

I would always use sp_executesql these days, all it really is is a wrapper for EXEC which handles parameters & variables.

However do not forget about OPTION RECOMPILE when tuning queries on very large databases, especially where you have data spanned over more than one database and are using a CONSTRAINT to limit index scans.

Unless you use OPTION RECOMPILE, SQL server will attempt to create a "one size fits all" execution plan for your query, and will run a full index scan each time it is run.

This is much less efficient than a seek, and means it is potentially scanning entire indexes which are constrained to ranges which you are not even querying :@

How to get PHP $_GET array?

You can specify an array in your HTML this way:

<input type="hidden" name="id[]" value="1"/>
<input type="hidden" name="id[]" value="2"/>
<input type="hidden" name="id[]" value="3"/>

This will result in this $_GET array in PHP:

array(
  'id' => array(
    0 => 1,
    1 => 2,
    2 => 3
  )
)

Of course, you can use any sort of HTML input, here. The important thing is that all inputs whose values you want in the 'id' array have the name id[].

How to use Apple's new San Francisco font on a webpage

Basically, this is what worked for me:

-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif 

P.S. This works on all systems.

How do I import a .bak file into Microsoft SQL Server 2012?

For SQL Server 2008, I would imagine the procedure is similar...?

  • open SQL Server Management Studio
  • log in to a SQL Server instance, right click on "Databases", select "Restore Database"
  • wizard appears, you want "from device" which allows you to select a .bak file

How to display my location on Google Maps for Android API v2

Call GoogleMap.setMyLocationEnabled(true) in your Activity, and add this 2 lines code in the Manifest:

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

Create database from command line

As the default configuration of Postgres, a user called postgres is made and the user postgres has full super admin access to entire PostgreSQL instance running on your OS.

sudo -u postgres psql

The above command gets you the psql command line interface in admin mode.

Creating user

sudo -u postgres createuser <username>

Creating Database

 sudo -u postgres createdb <dbname>

NOTE: < > are not to be used while writing command, they are used just to signify the variables

How do I create a MongoDB dump of my database?

take mongodb backup for particular db and delete 7 days old backup using bin sh command :-

#!/bin/bash

MONGO_DATABASE="nexgtv_16"
APP_NAME="test"
MONGO_HOST="127.0.0.1"
MONGO_PORT="27017"
TIMESTAMP=`date +%F-%H%M`
MONGODUMP_PATH="/usr/bin/mongodump"
BACKUPS_DIR="/home/mongodbbackups/backups/$APP_NAME"
BACKUP_NAME="$APP_NAME-$TIMESTAMP"
$MONGODUMP_PATH -d $MONGO_DATABASE
mkdir -p $BACKUPS_DIR
mv dump $BACKUP_NAME
tar -zcvf $BACKUPS_DIR/$BACKUP_NAME.tgz $BACKUP_NAME
rm -rf $BACKUP_NAME
find /home/mongodbbackups/backups/test/ -mindepth 1 -mtime +7 -delete

Python: how to capture image from webcam on click using OpenCV

Here is a simple program that displays the camera feed in a cv2.namedWindow and will take a snapshot when you hit SPACE. It will also quit if you hit ESC.

import cv2

cam = cv2.VideoCapture(0)

cv2.namedWindow("test")

img_counter = 0

while True:
    ret, frame = cam.read()
    if not ret:
        print("failed to grab frame")
        break
    cv2.imshow("test", frame)

    k = cv2.waitKey(1)
    if k%256 == 27:
        # ESC pressed
        print("Escape hit, closing...")
        break
    elif k%256 == 32:
        # SPACE pressed
        img_name = "opencv_frame_{}.png".format(img_counter)
        cv2.imwrite(img_name, frame)
        print("{} written!".format(img_name))
        img_counter += 1

cam.release()

cv2.destroyAllWindows()

I think this should answer your question for the most part. If there is any line of it that you don't understand let me know and I'll add comments.

If you need to grab multiple images per press of the SPACE key, you will need an inner loop or perhaps just make a function that grabs a certain number of images.

Note that the key events are from the cv2.namedWindow so it has to have focus.

CSS Input Type Selectors - Possible to have an "or" or "not" syntax?

CSS3 has a pseudo-class called :not()

_x000D_
_x000D_
input:not([type='checkbox']) {    
    visibility: hidden;
}
_x000D_
<p>If <code>:not()</code> is supported, you'll only see the checkbox.</p>
                                      
<ul>
  <li>text: (<input type="text">)</li>  
  <li>password (<input type="password">)</li>       
  <li>checkbox (<input type="checkbox">)</li> 
 </ul>
_x000D_
_x000D_
_x000D_


Multiple selectors

As Vincent mentioned, it's possible to string multiple :not()s together:

input:not([type='checkbox']):not([type='submit'])

CSS4, which is supported in many of the latest browser releases, allows multiple selectors in a :not()

input:not([type='checkbox'],[type='submit'])

Legacy support

All modern browsers support the CSS3 syntax. At the time this question was asked, we needed a fall-back for IE7 and IE8. One option was to use a polyfill like IE9.js. Another was to exploit the cascade in CSS:

input {
   // styles for most inputs
}   

input[type=checkbox] {
  // revert back to the original style
} 

input.checkbox {
  // for completeness, this would have worked even in IE3!
} 

Swift: Determine iOS Screen size

In Swift 3.0

let screenSize = UIScreen.main.bounds
let screenWidth = screenSize.width
let screenHeight = screenSize.height

In older swift: Do something like this:

let screenSize: CGRect = UIScreen.mainScreen().bounds

then you can access the width and height like this:

let screenWidth = screenSize.width
let screenHeight = screenSize.height

if you want 75% of your screen's width you can go:

let screenWidth = screenSize.width * 0.75

Swift 4.0

// Screen width.
public var screenWidth: CGFloat {
    return UIScreen.main.bounds.width
}

// Screen height.
public var screenHeight: CGFloat {
    return UIScreen.main.bounds.height
}

In Swift 5.0

let screenSize: CGRect = UIScreen.main.bounds

Bootstrap: change background color

You could hard code it.

<div class="col-md-6" style="background-color:blue;">
</div>

<div class="col-md-6" style="background-color:white;">
</div>

kill a process in bash

You can use the command pkill to kill processes. If you want to "play around", you can use "pgrep", which works exactly the same but returns the process rather than killing it.

pkill has the -f parameter that allows you to match against the entire command. So for your example, you can: pkill -f "gedit file.txt"

C++: How to round a double to an int?

add 0.5 before casting (if x > 0) or subtract 0.5 (if x < 0), because the compiler will always truncate.

float x = 55; // stored as 54.999999...
x = x + 0.5 - (x<0); // x is now 55.499999...
int y = (int)x; // truncated to 55

C++11 also introduces std::round, which likely uses a similar logic of adding 0.5 to |x| under the hood (see the link if interested) but is obviously more robust.

A follow up question might be why the float isn't stored as exactly 55. For an explanation, see this stackoverflow answer.

XmlDocument - load from string?

XmlDocument doc = new XmlDocument();
doc.LoadXml(str);

Where str is your XML string. See the MSDN article for more info.

Bootstrap: align input with button

style="padding-top: 8px"

Use this to shift your div up or down in your row. Works wonders for me.

Sharing url link does not show thumbnail image on facebook

I found out that the image that you are specify with the og:image, has to actually be present in the HTML page inside an image tag.

the thumbnail appeared for me only after i added an image tag for the image. it was commented out. but worked.

SOAP vs REST (differences)

First of all: officially, the correct question would be web services + WSDL + SOAP vs REST.

Because, although the web service, is used in the loose sense, when using the HTTP protocol to transfer data instead of web pages, officially it is a very specific form of that idea. According to the definition, REST is not "web service".

In practice however, everyone ignores that, so let's ignore it too

There are already technical answers, so I'll try to provide some intuition.

Let's say you want to call a function in a remote computer, implemented in some other programming language (this is often called remote procedure call/RPC). Assume that function can be found at a specific URL, provided by the person who wrote it. You have to (somehow) send it a message, and get some response. So, there are two main questions to consider.

  • what is the format of the message you should send
  • how should the message be carried back and forth

For the first question, the official definition is WSDL. This is an XML file which describes, in detailed and strict format, what are the parameters, what are their types, names, default values, the name of the function to be called, etc. An example WSDL here shows that the file is human-readable (but not easily).

For the second question, there are various answers. However, the only one used in practice is SOAP. Its main idea is: wrap the previous XML (the actual message) into yet another XML (containing encoding info and other helpful stuff), and send it over HTTP. The POST method of the HTTP is used to send the message, since there is always a body.

The main idea of this whole approach is that you map a URL to a function, that is, to an action. So, if you have a list of customers in some server, and you want to view/update/delete one, you must have 3 URLS:

  • myapp/read-customer and in the body of the message, pass the id of the customer to be read.
  • myapp/update-customer and in the body, pass the id of the customer, as well as the new data
  • myapp/delete-customer and the id in the body

The REST approach sees things differently. A URL should not represent an action, but a thing (called resource in the REST lingo). Since the HTTP protocol (which we are already using) supports verbs, use those verbs to specify what actions to perform on the thing.

So, with the REST approach, customer number 12 would be found on URL myapp/customers/12. To view the customer data, you hit the URL with a GET request. To delete it, the same URL, with a DELETE verb. To update it, again, the same URL with a POST verb, and the new content in the request body.

For more details about the requirements that a service has to fulfil to be considered truly RESTful, see the Richardson maturity model. The article gives examples, and, more importantly, explains why a (so-called) SOAP service, is a level-0 REST service (although, level-0 means low compliance to this model, it's not offensive, and it is still useful in many cases).

hasNext in Python iterators?

In addition to all the mentions of StopIteration, the Python "for" loop simply does what you want:

>>> it = iter("hello")
>>> for i in it:
...     print i
...
h
e
l
l
o

Getting datarow values into a string?

You need to specify which column of the datarow you want to pull data from.

Try the following:

        StringBuilder output = new StringBuilder();
        foreach (DataRow rows in results.Tables[0].Rows)
        {
            foreach (DataColumn col in results.Tables[0].Columns)
            {
                output.AppendFormat("{0} ", rows[col]);
            }

            output.AppendLine();
        }

How to start working with GTest and CMake

You can get the best of both worlds. It is possible to use ExternalProject to download the gtest source and then use add_subdirectory() to add it to your build. This has the following advantages:

  • gtest is built as part of your main build, so it uses the same compiler flags, etc. and hence avoids problems like the ones described in the question.
  • There's no need to add the gtest sources to your own source tree.

Used in the normal way, ExternalProject won't do the download and unpacking at configure time (i.e. when CMake is run), but you can get it to do so with just a little bit of work. I've written a blog post on how to do this which also includes a generalised implementation which works for any external project which uses CMake as its build system, not just gtest. You can find them here:

Update: This approach is now also part of the googletest documentation.

Missing `server' JVM (Java\jre7\bin\server\jvm.dll.)

To Fix The "Missing "server" JVM at C:\Program Files\Java\jre7\bin\server\jvm­­.dll, please install or use the JRE or JDK that contains these missing components.

Follow these steps:

Go to oracle.com and install Java JRE7 (Check if Java 6 is not installed already)

After that, go to C:/Program files/java/jre7/bin

Here, create an folder called Server

Now go into the C:/Program files/java/jre7/bin/client folder

Copy all the data in this folder into the new C:/Program files/java/jre7/bin/Server folder

How to preserve request url with nginx proxy_pass

Just proxy_set_header Host $host miss port for my case. Solved by:



    location / {
     proxy_pass http://BACKENDIP/;
     include /etc/nginx/proxy.conf;
    }

and then in the proxy.conf



    proxy_redirect off;
    proxy_set_header Host $host:$server_port;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

cannot be cast to java.lang.Comparable

  • the object which implements Comparable is Fegan.

The method compareTo you are overidding in it should have a Fegan object as a parameter whereas you are casting it to a FoodItems. Your compareTo implementation should describe how a Fegan compare to another Fegan.

  • To actually do your sorting, you might want to make your FoodItems implement Comparable aswell and copy paste your actual compareTo logic in it.

SQL Server : login success but "The database [dbName] is not accessible. (ObjectExplorer)"

In my case it worked when I had opened SQL Server Management Studio with Administrator credentials and I right-clicked on the database and select "Go online" or something like this.

How do you create a Marker with a custom icon for google maps API v3?

LatLng hello = new LatLng(X, Y);          // whereX & Y are coordinates

Bitmap icon = BitmapFactory.decodeResource(getApplicationContext().getResources(),
                R.drawable.university);   // where university is the icon name that is used as a marker.

mMap.addMarker(new MarkerOptions().icon(BitmapDescriptorFactory.fromBitmap(icon)).position(hello).title("Hello World!"));

mMap.moveCamera(CameraUpdateFactory.newLatLng(hello));

OR is not supported with CASE Statement in SQL Server

CASE
  WHEN ebv.db_no = 22978 OR 
       ebv.db_no = 23218 OR
       ebv.db_no = 23219
  THEN 'WECS 9500' 
  ELSE 'WECS 9520' 
END as wecs_system 

"configuration file /etc/nginx/nginx.conf test failed": How do I know why this happened?

sudo nginx -t should test all files and return errors and warnings locations

Putting images with options in a dropdown list

You can't do that in plain HTML, but you can do it with jQuery:

JavaScript Image Dropdown

Are you tired with your old fashion dropdown? Try this new one. Image combo box. You can add an icon with each option. It works with your existing "select" element or you can create by JSON object.

What's the difference between a single precision and double precision floating point operation?

All have explained in great detail and nothing I could add further. Though I would like to explain it in Layman's Terms or plain ENGLISH

1.9 is less precise than 1.99
1.99 is less precise than 1.999
1.999 is less precise than 1.9999

.....

A variable, able to store or represent "1.9" provides less precision than the one able to hold or represent 1.9999. These Fraction can amount to a huge difference in large calculations.

Python: fastest way to create a list of n lists

So I did some speed comparisons to get the fastest way. List comprehensions are indeed very fast. The only way to get close is to avoid bytecode getting exectuded during construction of the list. My first attempt was the following method, which would appear to be faster in principle:

l = [[]]
for _ in range(n): l.extend(map(list,l))

(produces a list of length 2**n, of course) This construction is twice as slow as the list comprehension, according to timeit, for both short and long (a million) lists.

My second attempt was to use starmap to call the list constructor for me, There is one construction, which appears to run the list constructor at top speed, but still is slower, but only by a tiny amount:

from itertools import starmap
l = list(starmap(list,[()]*(1<<n)))

Interesting enough the execution time suggests that it is the final list call that is makes the starmap solution slow, since its execution time is almost exactly equal to the speed of:

l = list([] for _ in range(1<<n))

My third attempt came when I realized that list(()) also produces a list, so I tried the apperently simple:

l = list(map(list, [()]*(1<<n)))

but this was slower than the starmap call.

Conclusion: for the speed maniacs: Do use the list comprehension. Only call functions, if you have to. Use builtins.

Commenting out a set of lines in a shell script

You can also put multi-line comments using:

: '
comment1comment1
comment2comment2
comment3comment3
comment4comment4
'

As per the Bash Reference for Bourne Shell builtins

: (a colon)

: [arguments]

Do nothing beyond expanding arguments and performing redirections. The return status is zero.

Thanks to Ikram for pointing this out in the post Shell script put multiple line comment

How to make a simple popup box in Visual C#?

Why not make use of a tooltip?

private void ShowToolTip(object sender, string message)
{
  new ToolTip().Show(message, this, Cursor.Position.X - this.Location.X, Cursor.Position.Y - this.Location.Y, 1000);
}

The code above will show message for 1000 milliseconds (1 second) where you clicked.

To call it, you can use the following in your button click event:

ShowToolTip("Hello World");

Creating a custom JButton in Java

Yes, this is possible. One of the main pros for using Swing is the ease with which the abstract controls can be created and manipulates.

Here is a quick and dirty way to extend the existing JButton class to draw a circle to the right of the text.

package test;

import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;

import javax.swing.JButton;
import javax.swing.JFrame;

public class MyButton extends JButton {

    private static final long serialVersionUID = 1L;

    private Color circleColor = Color.BLACK;

    public MyButton(String label) {
        super(label);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);

        Dimension originalSize = super.getPreferredSize();
        int gap = (int) (originalSize.height * 0.2);
        int x = originalSize.width + gap;
        int y = gap;
        int diameter = originalSize.height - (gap * 2);

        g.setColor(circleColor);
        g.fillOval(x, y, diameter, diameter);
    }

    @Override
    public Dimension getPreferredSize() {
        Dimension size = super.getPreferredSize();
        size.width += size.height;
        return size;
    }

    /*Test the button*/
    public static void main(String[] args) {
        MyButton button = new MyButton("Hello, World!");

        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 400);

        Container contentPane = frame.getContentPane();
        contentPane.setLayout(new FlowLayout());
        contentPane.add(button);

        frame.setVisible(true);
    }

}

Note that by overriding paintComponent that the contents of the button can be changed, but that the border is painted by the paintBorder method. The getPreferredSize method also needs to be managed in order to dynamically support changes to the content. Care needs to be taken when measuring font metrics and image dimensions.

For creating a control that you can rely on, the above code is not the correct approach. Dimensions and colours are dynamic in Swing and are dependent on the look and feel being used. Even the default Metal look has changed across JRE versions. It would be better to implement AbstractButton and conform to the guidelines set out by the Swing API. A good starting point is to look at the javax.swing.LookAndFeel and javax.swing.UIManager classes.

http://docs.oracle.com/javase/8/docs/api/javax/swing/LookAndFeel.html

http://docs.oracle.com/javase/8/docs/api/javax/swing/UIManager.html

Understanding the anatomy of LookAndFeel is useful for writing controls: Creating a Custom Look and Feel

Functional style of Java 8's Optional.ifPresent and if-not-Present?

You cannot call orElse after ifPresent, the reason is, orElse is called on an optiional but ifPresent returns void. So the best approach to achieve is ifPresentOrElse. It could be like this:

op.ifPresentOrElse( 
            (value) 
                -> { System.out.println( 
                         "Value is present, its: "
                         + value); }, 
            () 
                -> { System.out.println( 
                         "Value is empty"); }); 

Entity Framework VS LINQ to SQL VS ADO.NET with stored procedures?

First off, if you're starting a new project, go with Entity Framework ("EF") - it now generates much better SQL (more like Linq to SQL does) and is easier to maintain and more powerful than Linq to SQL ("L2S"). As of the release of .NET 4.0, I consider Linq to SQL to be an obsolete technology. MS has been very open about not continuing L2S development further.

1) Performance

This is tricky to answer. For most single-entity operations (CRUD) you will find just about equivalent performance with all three technologies. You do have to know how EF and Linq to SQL work in order to use them to their fullest. For high-volume operations like polling queries, you may want to have EF/L2S "compile" your entity query such that the framework doesn't have to constantly regenerate the SQL, or you can run into scalability issues. (see edits)

For bulk updates where you're updating massive amounts of data, raw SQL or a stored procedure will always perform better than an ORM solution because you don't have to marshal the data over the wire to the ORM to perform updates.

2) Speed of Development

In most scenarios, EF will blow away naked SQL/stored procs when it comes to speed of development. The EF designer can update your model from your database as it changes (upon request), so you don't run into synchronization issues between your object code and your database code. The only time I would not consider using an ORM is when you're doing a reporting/dashboard type application where you aren't doing any updating, or when you're creating an application just to do raw data maintenance operations on a database.

3) Neat/Maintainable code

Hands down, EF beats SQL/sprocs. Because your relationships are modeled, joins in your code are relatively infrequent. The relationships of the entities are almost self-evident to the reader for most queries. Nothing is worse than having to go from tier to tier debugging or through multiple SQL/middle tier in order to understand what's actually happening to your data. EF brings your data model into your code in a very powerful way.

4) Flexibility

Stored procs and raw SQL are more "flexible". You can leverage sprocs and SQL to generate faster queries for the odd specific case, and you can leverage native DB functionality easier than you can with and ORM.

5) Overall

Don't get caught up in the false dichotomy of choosing an ORM vs using stored procedures. You can use both in the same application, and you probably should. Big bulk operations should go in stored procedures or SQL (which can actually be called by the EF), and EF should be used for your CRUD operations and most of your middle-tier's needs. Perhaps you'd choose to use SQL for writing your reports. I guess the moral of the story is the same as it's always been. Use the right tool for the job. But the skinny of it is, EF is very good nowadays (as of .NET 4.0). Spend some real time reading and understanding it in depth and you can create some amazing, high-performance apps with ease.

EDIT: EF 5 simplifies this part a bit with auto-compiled LINQ Queries, but for real high volume stuff, you'll definitely need to test and analyze what fits best for you in the real world.

How to add an auto-incrementing primary key to an existing table, in PostgreSQL?

(Updated - Thanks to the people who commented)

Modern Versions of PostgreSQL

Suppose you have a table named test1, to which you want to add an auto-incrementing, primary-key id (surrogate) column. The following command should be sufficient in recent versions of PostgreSQL:

   ALTER TABLE test1 ADD COLUMN id SERIAL PRIMARY KEY;

Older Versions of PostgreSQL

In old versions of PostgreSQL (prior to 8.x?) you had to do all the dirty work. The following sequence of commands should do the trick:

  ALTER TABLE test1 ADD COLUMN id INTEGER;
  CREATE SEQUENCE test_id_seq OWNED BY test1.id;
  ALTER TABLE test ALTER COLUMN id SET DEFAULT nextval('test_id_seq');
  UPDATE test1 SET id = nextval('test_id_seq');

Again, in recent versions of Postgres this is roughly equivalent to the single command above.

Javascript string replace with regex to strip off illegal characters

I tend to look at it from the inverse perspective which may be what you intended:

What characters do I want to allow?

This is because there could be lots of characters that make in into a string somehow that blow stuff up that you wouldn't expect.

For example this one only allows for letters and numbers removing groups of invalid characters replacing them with a hypen:

"This¢£«±Ÿ÷could&*()\/<>be!@#$%^bad".replace(/([^a-z0-9]+)/gi, '-');
//Result: "This-could-be-bad"

Paused in debugger in chrome?

Its really a bad experience. if the above answer didn't work for you try this.

Click on the Settings icon and then click on the Restore defaults and reload button.

Press 'F8' until its became normal.

Happy coding!!

Can't find out where does a node.js app running and can't kill it

You can kill all node processes using pkill node

or you can do a ps T to see all processes on this terminal
then you can kill a specific process ID doing a kill [processID] example: kill 24491

Additionally, you can do a ps -help to see all the available options

LEFT function in Oracle

I've discovered that LEFT and RIGHT are not supported functions in Oracle. They are used in SQL Server, MySQL, and some other versions of SQL. In Oracle, you need to use the SUBSTR function. Here are simple examples:

LEFT ('Data', 2) = 'Da'

->   SUBSTR('Data',1,2) = 'Da'

RIGHT ('Data', 2) = 'ta'

->   SUBSTR('Data',-2,2) = 'ta'

Notice that a negative number counts back from the end.

How can I split and parse a string in Python?

"2.7.0_bf4fda703454".split("_") gives a list of strings:

In [1]: "2.7.0_bf4fda703454".split("_")
Out[1]: ['2.7.0', 'bf4fda703454']

This splits the string at every underscore. If you want it to stop after the first split, use "2.7.0_bf4fda703454".split("_", 1).

If you know for a fact that the string contains an underscore, you can even unpack the LHS and RHS into separate variables:

In [8]: lhs, rhs = "2.7.0_bf4fda703454".split("_", 1)

In [9]: lhs
Out[9]: '2.7.0'

In [10]: rhs
Out[10]: 'bf4fda703454'

An alternative is to use partition(). The usage is similar to the last example, except that it returns three components instead of two. The principal advantage is that this method doesn't fail if the string doesn't contain the separator.

In Java, how can I determine if a char array contains a particular character?

You can iterate through the array or you can convert it to a String and use indexOf.

if (new String(charArray).indexOf('q') < 0) {
    break;
}

Creating a new String is a bit wasteful, but it's probably the tersest code. You can also write a method to imitate the effect without incurring the overhead.

Get a list of all threads currently running in Java

You can try something like this:

Thread.getAllStackTraces().keySet().forEach((t) -> System.out.println(t.getName() + "\nIs Daemon " + t.isDaemon() + "\nIs Alive " + t.isAlive()));

and you can obviously get more thread characteristic if you need.

Regex for allowing alphanumeric,-,_ and space

var regex = new RegExp("^[A-Za-z0-9? ,_-]+$");
            var key = String.fromCharCode(event.charCode ? event.which : event.charCode);
            if (!regex.test(key)) {
                event.preventDefault();
                return false;
            }

in the regExp [A-Za-z0-9?spaceHere,_-] there is a literal space after the question mark '?'. This matches space. Others like /^[-\w\s]+$/ and /^[a-z\d\-_\s]+$/i were not working for me.

Notepad++ Multi editing

In the position where you want to add text, do:

Shift + Alt + down arrow

and select the lines you want. Then type. The text you type is inserted on all of the lines you selected.

How to get current user who's accessing an ASP.NET application?

The quick answer is User = System.Web.HttpContext.Current.User

Ensure your web.config has the following authentication element.

<configuration>
    <system.web>
        <authentication mode="Windows" />
        <authorization>
            <deny users="?"/>
        </authorization>
    </system.web>
</configuration>

Further Reading: Recipe: Enabling Windows Authentication within an Intranet ASP.NET Web application

How to get AIC from Conway–Maxwell-Poisson regression via COM-poisson package in R?

I figured out myself.

cmp calls ComputeBetasAndNuHat which returns a list which has objective as minusloglik

So I can change the function cmp to get this value.

"The system cannot find the file specified" when running C++ program

I came across this problem and none of these solution worked 100%

In addition to ReturnVoid's answer which suggested the change

Project Properties -> Linker -> Output file -> $(OutDir)$(TargetName)$(TargetExt)

I needed to changed

Project Properties -> C/C++ -> Debug Information Format -> /Zi

This field was blank for me, changing the contents to /Zi (or /Z7 or /ZI if those are the formats you want to use) allowed me to debug

instanceof Vs getClass( )

Do you want to match a class exactly, e.g. only matching FileInputStream instead of any subclass of FileInputStream? If so, use getClass() and ==. I would typically do this in an equals, so that an instance of X isn't deemed equal to an instance of a subclass of X - otherwise you can get into tricky symmetry problems. On the other hand, that's more usually useful for comparing that two objects are of the same class than of one specific class.

Otherwise, use instanceof. Note that with getClass() you will need to ensure you have a non-null reference to start with, or you'll get a NullPointerException, whereas instanceof will just return false if the first operand is null.

Personally I'd say instanceof is more idiomatic - but using either of them extensively is a design smell in most cases.

Best Practice to Use HttpClient in Multithreaded Environment

Definitely Method A because its pooled and thread safe.

If you are using httpclient 4.x, the connection manager is called ThreadSafeClientConnManager. See this link for further details (scroll down to "Pooling connection manager"). For example:

    HttpParams params = new BasicHttpParams();
    SchemeRegistry registry = new SchemeRegistry();
    registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
    ClientConnectionManager cm = new ThreadSafeClientConnManager(params, registry);
    HttpClient client = new DefaultHttpClient(cm, params);

ORA-00904: invalid identifier

Are you sure you have a column DEPARTEMENT_CODE on your table PS_TBL_DEPARTMENT_DETAILS

More informations about your ERROR

ORA-00904: string: invalid identifier Cause: The column name entered is either missing or invalid. Action: Enter a valid column name. A valid column name must begin with a letter, be less than or equal to 30 characters, and consist of only alphanumeric characters and the special characters $, _, and #. If it contains other characters, then it must be enclosed in d double quotation marks. It may not be a reserved word.

JavaScript Array to Set

Just pass the array to the Set constructor. The Set constructor accepts an iterable parameter. The Array object implements the iterable protocol, so its a valid parameter.

_x000D_
_x000D_
var arr = [55, 44, 65];_x000D_
var set = new Set(arr);_x000D_
console.log(set.size === arr.length);_x000D_
console.log(set.has(65));
_x000D_
_x000D_
_x000D_

See here

How to leave/exit/deactivate a Python virtualenv

To activate a Python virtual environment:

$cd ~/python-venv/
$./bin/activate

To deactivate:

$deactivate

Unable to Install Any Package in Visual Studio 2015

In general closing and re-open VS 2015 fixed most problems I have ran across. Once I did need to run a repair on one of my computers.

However I was about to do this Closing and re-opening VS2015 resolved the issue for me I figured that I would instead right click on the project and Unload Project then right click and Reload project THEN Manage Nuget worked!

How to use an environment variable inside a quoted string in Bash

The following script works for me for multiple values of $COLUMNS. I wonder if you are not setting COLUMNS prior to this call?

#!/bin/bash
COLUMNS=30
svn diff $@ --diff-cmd /usr/bin/diff -x "-y -w -p -W $COLUMNS"

Can you echo $COLUMNS inside your script to see if it set correctly?

bool to int conversion

int x = 4<5;

Completely portable. Standard conformant. bool to int conversion is implicit!

§4.7/4 from the C++ Standard says (Integral Conversion)

If the source type is bool, the value false is converted to zero and the value true is converted to one.


As for C, as far as I know there is no bool in C. (before 1999) So bool to int conversion is relevant in C++ only. In C, 4<5 evaluates to int value, in this case the value is 1, 4>5 would evaluate to 0.

EDIT: Jens in the comment said, C99 has _Bool type. bool is a macro defined in stdbool.h header file. true and false are also macro defined in stdbool.h.

§7.16 from C99 says,

The macro bool expands to _Bool.

[..] true which expands to the integer constant 1, false which expands to the integer constant 0,[..]

Number of rows affected by an UPDATE in PL/SQL

SQL%ROWCOUNT can also be used without being assigned (at least from Oracle 11g).

As long as no operation (updates, deletes or inserts) has been performed within the current block, SQL%ROWCOUNT is set to null. Then it stays with the number of line affected by the last DML operation:

say we have table CLIENT

create table client (
  val_cli integer
 ,status varchar2(10)
)
/

We would test it this way:

begin
  dbms_output.put_line('Value when entering the block:'||sql%rowcount);

  insert into client 
            select 1, 'void' from dual
  union all select 4, 'void' from dual
  union all select 1, 'void' from dual
  union all select 6, 'void' from dual
  union all select 10, 'void' from dual;  
  dbms_output.put_line('Number of lines affected by previous DML operation:'||sql%rowcount);

  for val in 1..10
    loop
      update client set status = 'updated' where val_cli = val;
      if sql%rowcount = 0 then
        dbms_output.put_line('no client with '||val||' val_cli.');
      elsif sql%rowcount = 1 then
        dbms_output.put_line(sql%rowcount||' client updated for '||val);
      else -- >1
        dbms_output.put_line(sql%rowcount||' clients updated for '||val);
      end if;
  end loop;  
end;

Resulting in:

Value when entering the block:
Number of lines affected by previous DML operation:5
2 clients updated for 1
no client with 2 val_cli.
no client with 3 val_cli.
1 client updated for 4
no client with 5 val_cli.
1 client updated for 6
no client with 7 val_cli.
no client with 8 val_cli.
no client with 9 val_cli.
1 client updated for 10

How to close a window using jQuery

$(element).click(function(){
    window.close();
});

Note: you can not close any window that you didn't opened with window.open. Directly invoking window.close() will ask user with a dialogue box.

How to manually force a commit in a @Transactional method?

I know that due to this ugly anonymous inner class usage of TransactionTemplate doesn't look nice, but when for some reason we want to have a test method transactional IMHO it is the most flexible option.

In some cases (it depends on the application type) the best way to use transactions in Spring tests is a turned-off @Transactional on the test methods. Why? Because @Transactional may leads to many false-positive tests. You may look at this sample article to find out details. In such cases TransactionTemplate can be perfect for controlling transaction boundries when we want that control.

Detecting an undefined object property

There are a few little helpers in the Lodash library:

isUndefined - to check if value is undefined.

_.isUndefined(undefined) // => true
_.isUndefined(null) // => false

has - to check if object contains a property

const object = { 'a': { 'b': 2 } }

_.has(object, 'a.b') // => true
_.has(object, 'a.c') // => false

Add items to comboBox in WPF

There are many ways to perform this task. Here is a simple one:

<Window x:Class="WPF_Demo1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     x:Name="TestWindow"
    Title="MainWindow" Height="500" Width="773">

<DockPanel LastChildFill="False">
    <StackPanel DockPanel.Dock="Top" Background="Red" Margin="2">
        <StackPanel Orientation="Horizontal" x:Name="spTopNav">
            <ComboBox x:Name="cboBox1" MinWidth="120"> <!-- Notice we have used x:Name to identify the object that we want to operate upon.-->
            <!--
                <ComboBoxItem Content="X"/>
                <ComboBoxItem Content="Y"/>
                <ComboBoxItem Content="Z"/>
            -->
            </ComboBox>
        </StackPanel>
    </StackPanel>
    <StackPanel DockPanel.Dock="Bottom" Background="Orange" Margin="2">
        <StackPanel Orientation="Horizontal" x:Name="spBottomNav">
        </StackPanel>
        <TextBlock Height="30" Foreground="White">Left Docked StackPanel 2</TextBlock>
    </StackPanel>
    <StackPanel MinWidth="200" DockPanel.Dock="Left" Background="Teal" Margin="2" x:Name="StackPanelLeft">
        <TextBlock  Foreground="White">Bottom Docked StackPanel Left</TextBlock>

    </StackPanel>
    <StackPanel DockPanel.Dock="Right" Background="Yellow" MinWidth="150" Margin="2" x:Name="StackPanelRight"></StackPanel>
    <Button Content="Button" Height="410" VerticalAlignment="Top" Width="75" x:Name="myButton" Click="myButton_Click"/>


</DockPanel>

</Window>      

Next, we have the C# code:

    private void myButton_Click(object sender, RoutedEventArgs e)
    {
        ComboBoxItem cboBoxItem = new ComboBoxItem(); // Create example instance of our desired type.
        Type type1 = cboBoxItem.GetType();
        object cboBoxItemInstance = Activator.CreateInstance(type1); // Construct an instance of that type.
        for (int i = 0; i < 12; i++)
        {
            string newName = "stringExample" + i.ToString();
           // Generate the objects from our list of strings.
            ComboBoxItem item = this.CreateComboBoxItem((ComboBoxItem)cboBoxItemInstance, "nameExample_" + newName, newName);
            cboBox1.Items.Add(item); // Add each newly constructed item to our NAMED combobox.
        }
    }
    private ComboBoxItem CreateComboBoxItem(ComboBoxItem myCbo, string content, string name)
    {
        Type type1 = myCbo.GetType();
        ComboBoxItem instance = (ComboBoxItem)Activator.CreateInstance(type1);
        // Here, we're using reflection to get and set the properties of the type.
        PropertyInfo Content = instance.GetType().GetProperty("Content", BindingFlags.Public | BindingFlags.Instance);
        PropertyInfo Name = instance.GetType().GetProperty("Name", BindingFlags.Public | BindingFlags.Instance);
        this.SetProperty<ComboBoxItem, String>(Content, instance, content);
        this.SetProperty<ComboBoxItem, String>(Name, instance, name);

        return instance;
        //PropertyInfo prop = type.GetProperties(rb1);
    }

Note: This is using reflection. If you'd like to learn more about the basics of reflection and why you might want to use it, this is a great introductory article:

If you'd like to learn more about how you might use reflection with WPF specifically, here are some resources:

And if you want to massively speed up the performance of reflection, it's best to use IL to do that, like this:

How to position the div popup dialog to the center of browser screen?

I think you need to make the .holder position:relative; and .popup position:absolute;

Why doesn't the height of a container element increase if it contains floated elements?

you can use overflow property to the container div if you don't have any div to show over the container eg:

<div class="cointainer">
    <div class="one">Content One</div>
    <div class="two">Content Two</div>
</div>

Here is the following css:

.container{
    width:100%;/* As per your requirment */
    height:auto;
    float:left;
    overflow:hidden;
}
.one{
    width:200px;/* As per your requirment */
    height:auto;
    float:left;
}

.two{
    width:200px;/* As per your requirment */
    height:auto;
    float:left;
}

-----------------------OR------------------------------

    <div class="cointainer">
        <div class="one">Content One</div>
        <div class="two">Content Two</div>
        <div class="clearfix"></div>
    </div>

Here is the following css:

    .container{
        width:100%;/* As per your requirment */
        height:auto;
        float:left;
        overflow:hidden;
    }
    .one{
        width:200px;/* As per your requirment */
        height:auto;
        float:left;
    }

    .two{
        width:200px;/* As per your requirment */
        height:auto;
        float:left;
    }
    .clearfix:before,
    .clearfix:after{
        display: table;
        content: " ";
    }
    .clearfix:after{
        clear: both;
    }

Targeting .NET Framework 4.5 via Visual Studio 2010

Each version of Visual Studio prior to Visual Studio 2010 is tied to a specific .NET framework. (VS2008 is .NET 3.5, VS2005 is .NET 2.0, VS2003 is .NET1.1) Visual Studio 2010 and beyond allow for targeting of prior framework versions but cannot be used for future releases. You must use Visual Studio 2012 in order to utilize .NET 4.5.

Disable asp.net button after click to prevent double clicking

<asp:Button ID="btnSend" runat="server" Text="Submit"  OnClick="Button_Click"/>

        <script type = "text/javascript">
            function DisableButton()
            {
                document.getElementById("<%=btnSend.ClientID %>").disabled = true;
            }
            window.onbeforeunload = DisableButton;
        </script>

Reading a key from the Web.Config using ConfigurationManager

This issue happens if this project is being used by another project. Make sure you copy the app setting keys to the parent project's app.config or web.config.

What is Java Servlet?

I think servlet is basically a java class which acts as a middle way between HTTP request and HTTP response.Servlet is also used to make your web page dynamic. Suppose for example if you want to redirect to another web page on server then you have to use servlets. Another important thing is that servlet can run on localhost as well as a web browser.

How to detect Ctrl+V, Ctrl+C using JavaScript?

i already have your problem and i solved it by the following code .. that accept only numbers

$('#<%= mobileTextBox.ClientID %>').keydown(function(e) {
            ///// e.which Values
            // 8  : BackSpace , 46 : Delete , 37 : Left , 39 : Rigth , 144: Num Lock 
            if (e.which != 8 && e.which != 46 && e.which != 37 && e.which != 39 && e.which != 144
                && (e.which < 96 || e.which > 105 )) {
                return false;
            }
        });

you can detect Ctrl id e.which == 17

Cannot ping AWS EC2 instance

  1. Go to EC2 Dashboard and click "Running Instances" on "Security Groups", select the group of your instance which you need to add security.
  2. click on the "Inbound" tab
  3. Click "Edit" Button (It will open an popup window)
  4. click "Add Rule"
  5. Select the "Custom ICMP rule - IPv4" as Type
  6. Select "Echo Request" and "Echo Response" as the Protocol (Port Range by default show as "N/A)
  7. Enter the "0.0.0.0/0" as Source
  8. Click "Save"

Is there a PowerShell "string does not contain" cmdlet or syntax?

If $arrayofStringsNotInterestedIn is an [array] you should use -notcontains:

Get-Content $FileName | foreach-object { `
   if ($arrayofStringsNotInterestedIn -notcontains $_) { $) }

or better (IMO)

Get-Content $FileName | where { $arrayofStringsNotInterestedIn -notcontains $_}

How do I redirect to the previous action in ASP.NET MVC?

If you are not concerned with unit testing then you can simply write:

return Redirect(ControllerContext.HttpContext.Request.UrlReferrer.ToString());