C# Telnet Library

Another one with a different concept: http://www.klausbasan.de/misc/telnet/index.html

Spark java.lang.OutOfMemoryError: Java heap space

Did you dump your master gc log? So I met similar issue and I found SPARK_DRIVER_MEMORY only set the Xmx heap. The initial heap size remains 1G and the heap size never scale up to the Xmx heap.

Passing "--conf "spark.driver.extraJavaOptions=-Xms20g" resolves my issue.

ps aux | grep java and the you'll see the follow log:=

24501 30.7 1.7 41782944 2318184 pts/0 Sl+ 18:49 0:33 /usr/java/latest/bin/java -cp /opt/spark/conf/:/opt/spark/jars/* -Xmx30g -Xms20g

Sending commands and strings to Terminal.app with Applescript

Kinda related, you might want to look at Shuttle (http://fitztrev.github.io/shuttle/), it's a SSH shortcut menu for OSX.

How do I execute a *.dll file

The following series of steps might be helpful:

Open Windows Explorer
In the top-left corner, click "Organize"
select "Folder and Search Options"
Switch to the "View" tab
Scroll down and uncheck "Hide file extensions for known file types"
Click OK
Now find the dll file
Right-click on it and select "Rename"
Change the extension(what comes after the last .) and change it to .exe

Division of integers in Java

As your output results a double you should cast either completed variable or total variable or both to double while dividing.

So, the correct implmentation will be:

System.out.println((double)completed/total);

Convert datetime value into string

Try this:

concat(left(datefield,10),left(timefield,8))

10 char on date field based on full date yyyy-MM-dd.
8 char on time field based on full time hh:mm:ss.

It depends on the format you want it. normally you can use script above and you can concat another field or string as you want it.

Because actually date and time field tread as string if you read it. But of course you will got error while update or insert it.

How do you remove an array element in a foreach loop?

There are already answers which are giving light on how to unset. Rather than repeating code in all your classes make function like below and use it in code whenever required. In business logic, sometimes you don't want to expose some properties. Please see below one liner call to remove

public static function removeKeysFromAssociativeArray($associativeArray, $keysToUnset)
{
    if (empty($associativeArray) || empty($keysToUnset))
        return array();

    foreach ($associativeArray as $key => $arr) {
        if (!is_array($arr)) {
            continue;
        }

        foreach ($keysToUnset as $keyToUnset) {
            if (array_key_exists($keyToUnset, $arr)) {
                unset($arr[$keyToUnset]);
            }
        }
        $associativeArray[$key] = $arr;
    }
    return $associativeArray;
}

Call like:

removeKeysFromAssociativeArray($arrValues, $keysToRemove);

How to get current screen width in CSS?

Use the CSS3 Viewport-percentage feature.

Viewport-Percentage Explanation

Assuming you want the body width size to be a ratio of the browser's view port. I added a border so you can see the body resize as you change your browser width or height. I used a ratio of 90% of the view-port size.

_x000D_

<!DOCTYPE html>_x000D_
<html lang="en">_x000D_
<head>_x000D_
    <title>Styles</title>_x000D_
_x000D_
    <style>_x000D_
        @media screen and (min-width: 480px) {_x000D_
            body {_x000D_
                background-color: skyblue;_x000D_
                width: 90vw;_x000D_
                height: 90vh;_x000D_
                border: groove black;_x000D_
            }_x000D_
_x000D_
            div#main {_x000D_
                font-size: 3vw;_x000D_
            }_x000D_
        }_x000D_
    </style>_x000D_
_x000D_
</head>_x000D_
<body>_x000D_
    <div id="main">_x000D_
        Viewport-Percentage Test_x000D_
    </div>_x000D_
</body>_x000D_
</html>

_x000D_

Placing border inside of div and not on its edge

Set box-sizing property to border-box:

_x000D_

div {_x000D_
    box-sizing: border-box;_x000D_
    -moz-box-sizing: border-box;_x000D_
    -webkit-box-sizing: border-box;_x000D_
    width: 100px;_x000D_
    height: 100px;_x000D_
    border: 20px solid #f00;_x000D_
    background: #00f;_x000D_
    margin: 10px;_x000D_
}_x000D_
_x000D_
div + div {_x000D_
    border: 10px solid red;_x000D_
}

_x000D_

<div>Hello!</div>_x000D_
<div>Hello!</div>

_x000D_

It works on IE8 & above.

Getting permission denied (public key) on gitlab

I added my ~/.ssh/id_rsa.pub to the list of known SSH Keys in my GitLab settings https://gitlab.com/profile/keys. That solved the problem for me. :-)

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

How to determine whether an object has a given property in JavaScript

One feature of my original code

if ( typeof(x.y) != 'undefined' ) ...

that might be useful in some situations is that it is safe to use whether x exists or not. With either of the methods in gnarf's answer, one should first test for x if there is any doubt if it exists.

So perhaps all three methods have a place in one's bag of tricks.

Rails: How can I set default values in ActiveRecord?

An even better/cleaner potential way than the answers proposed is to overwrite the accessor, like this:

def status
  self['status'] || ACTIVE
end

See "Overwriting default accessors" in the ActiveRecord::Base documentation and more from StackOverflow on using self.

Converting double to string

How about when you do the

totalCost.setText(tot);

You just do

totalCost.setText( "" + total );

Where the "" + < variable > will convert it to string automaticly

How to compare strings in C conditional preprocessor-directives

It's simple I think you can just say

#define NAME JACK    
#if NAME == queen

How to call an element in a numpy array?

Also, you could try to use ndarray.item(), for example, arr.item((0, 0))(rowid+colid to index) or arr.item(0)(flatten index), its doc https://docs.scipy.org/doc/numpy/reference/generated/numpy.ndarray.item.html

How to generate graphs and charts from mysql database in php

I use Google Chart Tools https://developers.google.com/chart/ It's well documented and the charts look great. Being javascript, you can feed it json data via ajax.

NameError: global name 'xrange' is not defined in Python 3

I solved the issue by adding this import
More info

from past.builtins import xrange

how much memory can be accessed by a 32 bit machine?

No your concepts are not right. And to set it right you need the answer to the question that you incorrectly answered:

What is meant by 32bit or 64 bit machine?

The answer to the question is "something significant in the CPU is 32bit or 64 bit". So the question is what is that something significant? Lot of people say the width of data bus that determine whether the machine is 32bit or 64 bit. But none of the latest 32 bit processors have 32 bit or 64 bit wide data buses. most 32 bit systems will have 36 bit at least to support more RAM. Most 64 bit processors have no more than 48bit wide data bus because that is hell lot of memory already.

So according to me a 32 bit or 64 bit machine is determined by the size of its general purpose registers used in computation or "the natural word size" used by the computer.

Note that a 32 bit OS is a different thing. You can have a 32 bit OS running on 64 bit computer. Additionally, you can have 32 bit application running on 64 bit OS. If you do not understand the difference, post another question.

So the maximum amount of RAM a processor can address is 2^(width of data bus in bits), given that the proper addressing mode is switched on in the processor.

Further note, there is nothing stopping someone to introduce a multiplex between data Bus and memory banks, that will select a bank and then address the RAM (in two steps). This way you can address even more RAM. But that is impractical, and highly inefficient.

Goal Seek Macro with Goal as a Formula

I think your issue is that Range("H18") doesn't contain a formula. Also, you could make your code more efficient by eliminating x. Instead, change your code to

Range("H18").GoalSeek Goal:=Range("H32").Value, ChangingCell:=Range("G18")

Maintain model of scope when changing between views in AngularJS

You can use $locationChangeStart event to store the previous value in $rootScope or in a service. When you come back, just initialize all previously stored values. Here is a quick demo using $rootScope.

_x000D_

var app = angular.module("myApp", ["ngRoute"]);_x000D_
app.controller("tab1Ctrl", function($scope, $rootScope) {_x000D_
    if ($rootScope.savedScopes) {_x000D_
        for (key in $rootScope.savedScopes) {_x000D_
            $scope[key] = $rootScope.savedScopes[key];_x000D_
        }_x000D_
    }_x000D_
    $scope.$on('$locationChangeStart', function(event, next, current) {_x000D_
        $rootScope.savedScopes = {_x000D_
            name: $scope.name,_x000D_
            age: $scope.age_x000D_
        };_x000D_
    });_x000D_
});_x000D_
app.controller("tab2Ctrl", function($scope) {_x000D_
    $scope.language = "English";_x000D_
});_x000D_
app.config(function($routeProvider) {_x000D_
    $routeProvider_x000D_
        .when("/", {_x000D_
            template: "<h2>Tab1 content</h2>Name: <input ng-model='name'/><br/><br/>Age: <input type='number' ng-model='age' /><h4 style='color: red'>Fill the details and click on Tab2</h4>",_x000D_
            controller: "tab1Ctrl"_x000D_
        })_x000D_
        .when("/tab2", {_x000D_
            template: "<h2>Tab2 content</h2> My language: {{language}}<h4 style='color: red'>Now go back to Tab1</h4>",_x000D_
            controller: "tab2Ctrl"_x000D_
        });_x000D_
});

_x000D_

<!DOCTYPE html>_x000D_
<html>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular.min.js"></script>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular-route.js"></script>_x000D_
<body ng-app="myApp">_x000D_
    <a href="#/!">Tab1</a>_x000D_
    <a href="#!tab2">Tab2</a>_x000D_
    <div ng-view></div>_x000D_
</body>_x000D_
</html>

_x000D_

No numeric types to aggregate - change in groupby() behaviour?

How are you generating your data?

See how the output shows that your data is of 'object' type? the groupby operations specifically check whether each column is a numeric dtype first.

In [31]: data
Out[31]: 
<class 'pandas.core.frame.DataFrame'>
DatetimeIndex: 2557 entries, 2004-01-01 00:00:00 to 2010-12-31 00:00:00
Freq: <1 DateOffset>
Columns: 360 entries, -89.75 to 89.75
dtypes: object(360)

look ?

Did you initialize an empty DataFrame first and then filled it? If so that's probably why it changed with the new version as before 0.9 empty DataFrames were initialized to float type but now they are of object type. If so you can change the initialization to DataFrame(dtype=float).

You can also call frame.astype(float)

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

Note: this only answers part of the question.

If you just want to know the maximum number of sessions allowed, then you can execute in sqlplus, as sysdba:

SQL> show parameter sessions

This gives you an output like:

    NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
java_max_sessionspace_size           integer     0
java_soft_sessionspace_limit         integer     0
license_max_sessions                 integer     0
license_sessions_warning             integer     0
sessions                             integer     248
shared_server_sessions               integer

The sessions parameter is the one what you want.

Bootstrap 3 modal vertical position center

.modal {
  text-align: center;
}

@media screen and (min-width: 768px) { 
  .modal:before {
    display: inline-block;
    vertical-align: middle;
    content: " ";
    height: 100%;
  }
}

.modal-dialog {
  display: inline-block;
  text-align: left;
  vertical-align: middle;
}

And adjust a little bit .fade class to make sure it appears out of the top border of window, instead of center

jQuery selector regular expressions

You can use the filter function to apply more complicated regex matching.

Here's an example which would just match the first three divs:

_x000D_

$('div')_x000D_
  .filter(function() {_x000D_
    return this.id.match(/abc+d/);_x000D_
  })_x000D_
  .html("Matched!");

_x000D_

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
_x000D_
<div id="abcd">Not matched</div>_x000D_
<div id="abccd">Not matched</div>_x000D_
<div id="abcccd">Not matched</div>_x000D_
<div id="abd">Not matched</div>

_x000D_

How to Define Callbacks in Android?

No need to define a new interface when you can use an existing one: android.os.Handler.Callback. Pass an object of type Callback, and invoke callback's handleMessage(Message msg).

Java method to sum any number of ints

import java.util.Scanner;

public class SumAll {
    public static void sumAll(int arr[]) {//initialize method return sum
        int sum = 0;
        for (int i = 0; i < arr.length; i++) {
            sum += arr[i];
        }
        System.out.println("Sum is : " + sum);
    }

    public static void main(String[] args) {
        int num;
        Scanner input = new Scanner(System.in);//create scanner object 
        System.out.print("How many # you want to add : ");
        num = input.nextInt();//return num from keyboard
        int[] arr2 = new int[num];
        for (int i = 0; i < arr2.length; i++) {
            System.out.print("Enter Num" + (i + 1) + ": ");
            arr2[i] = input.nextInt();
        }
        sumAll(arr2);
    }

}

Getting Python error "from: can't read /var/mail/Bio"

Same here. I had this error when running an import command from terminal without activating python3 shell through manage.py in a django project (yes, I am a newbie yet). As one must expect, activating shell allowed the command to be interpreted correctly.

./manage.py shell

and only then

>>> from django.contrib.sites.models import Site

Convert dataframe column to 1 or 0 for "true"/"false" values and assign to dataframe

Try this, it will convert True into 1 and False into 0:

data.frame$column.name.num  <- as.numeric(data.frame$column.name)

Then you can convert into factor if you want:

data.frame$column.name.num.factor <- as .factor(data.frame$column.name.num)

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

Some of you guys have great answers, but I found some additional thing. If you want create a MenuItem with some SubMenu programmatically:

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        SubMenu subMenu = menu.addSubMenu(0, Menu.NONE, 0, "Menu title");
        subMenu.getItem().setIcon(R.drawable.ic_action_child);
        subMenu.getItem().setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);

        subMenu.add(0, Menu.NONE, 0, "Subitem 1");
        subMenu.add(0, Menu.NONE, 1, "Subitem 2");
        subMenu.add(0, Menu.NONE, 2, "Subitem 3");

        return true;
    }

How do you use Intent.FLAG_ACTIVITY_CLEAR_TOP to clear the Activity Stack?

I use three flags to resolve the problem:

intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|
                Intent.FLAG_ACTIVITY_CLEAR_TASK | 
                Intent.FLAG_ACTIVITY_NEW_TASK);

jQuery’s .bind() vs. .on()

As of Jquery 3.0 and above .bind has been deprecated and they prefer using .on instead. As @Blazemonger answered earlier that it may be removed and its for sure that it will be removed. For the older versions .bind would also call .on internally and there is no difference between them. Please also see the api for more detail.

jQuery API documentation for .bind()

Better naming in Tuple classes than "Item1", "Item2"

Just to add to @MichaelMocko answer. Tuples have couple of gotchas at the moment:

You can't use them in EF expression trees

Example:

public static (string name, string surname) GetPersonName(this PersonContext ctx, int id)
{
    return ctx.Persons
        .Where(person => person.Id == id)
        // Selecting as Tuple
        .Select(person => (person.Name, person.Surname))
        .First();
}

This will fail to compile with "An expression tree may not contain a tuple literal" error. Unfortunately, the expression trees API wasn't expanded with support for tuples when these were added to the language.

Track (and upvote) this issue for the updates: https://github.com/dotnet/roslyn/issues/12897

To get around the problem, you can cast it to anonymous type first and then convert the value to tuple:

// Will work
public static (string name, string surname) GetPersonName(this PersonContext ctx, int id)
{
    return ctx.Persons
        .Where(person => person.Id == id)
        .Select(person => new { person.Name, person.Surname })
        .ToList()
        .Select(person => (person.Name, person.Surname))
        .First();
}

Another option is to use ValueTuple.Create:

// Will work
public static (string name, string surname) GetPersonName(this PersonContext ctx, int id)
{
    return ctx.Persons
        .Where(person => person.Id == id)
        .Select(person => ValueTuple.Create(person.Name, person.Surname))
        .First();
}

References:

You can't deconstruct them in lambdas

There's a proposal to add the support: https://github.com/dotnet/csharplang/issues/258

Example:

public static IQueryable<(string name, string surname)> GetPersonName(this PersonContext ctx, int id)
{
    return ctx.Persons
        .Where(person => person.Id == id)
        .Select(person => ValueTuple.Create(person.Name, person.Surname));
}

// This won't work
ctx.GetPersonName(id).Select((name, surname) => { return name + surname; })

// But this will
ctx.GetPersonName(id).Select(t => { return t.name + t.surname; })

References:

C# 7 tuples and lambdas

They won't serialize nicely

using System;
using Newtonsoft.Json;

public class Program
{
    public static void Main() {
        var me = (age: 21, favoriteFood: "Custard");
        string json = JsonConvert.SerializeObject(me);

        // Will output {"Item1":21,"Item2":"Custard"}
        Console.WriteLine(json); 
    }
}

Tuple field names are only available at compile time and are completely wiped out at runtime.

References:

react-router getting this.props.location in child components

(Update) V5.1 & Hooks (Requires React >= 16.8)

You can use useHistory, useLocation and useRouteMatch in your component to get match, history and location .

const Child = () => {
  const location = useLocation();
  const history = useHistory();
  const match = useRouteMatch("write-the-url-you-want-to-match-here");

  return (
    <div>{location.pathname}</div>
  )
}

export default Child

(Update) V4 & V5

You can use withRouter HOC in order to inject match, history and location in your component props.

class Child extends React.Component {
  static propTypes = {
    match: PropTypes.object.isRequired,
    location: PropTypes.object.isRequired,
    history: PropTypes.object.isRequired
  }

  render() {
    const { match, location, history } = this.props

    return (
      <div>{location.pathname}</div>
    )
  }
}

export default withRouter(Child)

(Update) V3

You can use withRouter HOC in order to inject router, params, location, routes in your component props.

class Child extends React.Component {

  render() {
    const { router, params, location, routes } = this.props

    return (
      <div>{location.pathname}</div>
    )
  }
}

export default withRouter(Child)

Original answer

If you don't want to use the props, you can use the context as described in React Router documentation

First, you have to set up your childContextTypes and getChildContext

class App extends React.Component{

  getChildContext() {
    return {
      location: this.props.location
    }
  }

  render() {
    return <Child/>;
  }
}

App.childContextTypes = {
    location: React.PropTypes.object
}

Then, you will be able to access to the location object in your child components using the context like this

class Child extends React.Component{

   render() {
     return (
       <div>{this.context.location.pathname}</div>
     )
   }

}

Child.contextTypes = {
    location: React.PropTypes.object
 }

How to search in commit messages using command line?

git log --grep=<pattern>
    Limit the commits output to ones with log message that matches the 
    specified pattern (regular expression).

--git help log

How do I jump to a closing bracket in Visual Studio Code?

You can learn commands from the command palette Ctrl/Cmd + Shift + P). Look for "Go to Bracket". The keybinding is also shown there.

How to check if a file exists in the Documents directory in Swift?

Swift 4.2

extension URL    {
    func checkFileExist() -> Bool {
        let path = self.path
        if (FileManager.default.fileExists(atPath: path))   {
            print("FILE AVAILABLE")
            return true
        }else        {
            print("FILE NOT AVAILABLE")
            return false;
        }
    }
}

Using: -

if fileUrl.checkFileExist()
   {
      // Do Something
   }

Prevent content from expanding grid items

The existing answers solve most cases. However, I ran into a case where I needed the content of the grid-cell to be overflow: visible. I solved it by absolutely positioning within a wrapper (not ideal, but the best I know), like this:


.month-grid {
  display: grid;
  grid-template: repeat(6, 1fr) / repeat(7, 1fr);
  background: #fff;
  grid-gap: 2px;  
}

.day-item-wrapper {
  position: relative;
}

.day-item {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 10px;

  background: rgba(0,0,0,0.1);
}

https://codepen.io/bjnsn/pen/vYYVPZv

How to trigger event when a variable's value is changed?

The .NET framework actually provides an interface that you can use for notifying subscribers when a property has changed: System.ComponentModel.INotifyPropertyChanged. This interface has one event PropertyChanged. Its usually used in WPF for binding but I have found it useful in business layers as a way to standardize property change notification.

In terms of thread safety I would put a lock under in the setter so that you don't run into any race conditions.

Here are my thoughts in code :) :

public class MyClass : INotifyPropertyChanged
{
    private object _lock;

    public int MyProperty
    {
        get
        {
            return _myProperty;
        }
        set
        {
            lock(_lock)
            {
                //The property changed event will get fired whenever
                //the value changes. The subscriber will do work if the value is
                //1. This way you can keep your business logic outside of the setter
                if(value != _myProperty)
                {
                    _myProperty = value;
                    NotifyPropertyChanged("MyProperty");
                }
            }
        }
    }

    private NotifyPropertyChanged(string propertyName)
    {
        //Raise PropertyChanged event
    }
    public event PropertyChangedEventHandler PropertyChanged;
}


public class MySubscriber
{
    private MyClass _myClass;        

    void PropertyChangedInMyClass(object sender, PropertyChangedEventArgs e)
    {
        switch(e.PropertyName)
        {
            case "MyProperty":
                DoWorkOnMyProperty(_myClass.MyProperty);
                break;
        }
    }

    void DoWorkOnMyProperty(int newValue)
    {
        if(newValue == 1)
        {
             //DO WORK HERE
        }
    }
}

Hope this is helpful :)

jQuery hasClass() - check for more than one class

filter() is another option

Reduce the set of matched elements to those that match the selector or pass the function's test.

$(selector).filter('.class1, .class2'); //Filter elements: class1 OR class2

$(selector).filter('.class1.class2'); // Filter elements: class1 AND class2

try/catch blocks with async/await

catching in this fashion, in my experience, is dangerous. Any error thrown in the entire stack will be caught, not just an error from this promise (which is probably not what you want).

The second argument to a promise is already a rejection/failure callback. It's better and safer to use that instead.

Here's a typescript typesafe one-liner I wrote to handle this:

function wait<R, E>(promise: Promise<R>): [R | null, E | null] {
  return (promise.then((data: R) => [data, null], (err: E) => [null, err]) as any) as [R, E];
}

// Usage
const [currUser, currUserError] = await wait<GetCurrentUser_user, GetCurrentUser_errors>(
  apiClient.getCurrentUser()
);

addEventListener vs onclick

Both are correct, but none of them are "best" per se, and there may be a reason the developer chose to use both approaches.

Event Listeners (addEventListener and IE's attachEvent)

Earlier versions of Internet Explorer implement javascript differently from pretty much every other browser. With versions less than 9, you use the attachEvent[doc] method, like this:

element.attachEvent('onclick', function() { /* do stuff here*/ });

In most other browsers (including IE 9 and above), you use addEventListener[doc], like this:

element.addEventListener('click', function() { /* do stuff here*/ }, false);

Using this approach (DOM Level 2 events), you can attach a theoretically unlimited number of events to any single element. The only practical limitation is client-side memory and other performance concerns, which are different for each browser.

The examples above represent using an anonymous function[doc]. You can also add an event listener using a function reference[doc] or a closure[doc]:

var myFunctionReference = function() { /* do stuff here*/ }

element.attachEvent('onclick', myFunctionReference);
element.addEventListener('click', myFunctionReference , false);

Another important feature of addEventListener is the final parameter, which controls how the listener reacts to bubbling events[doc]. I've been passing false in the examples, which is standard for probably 95% of use cases. There is no equivalent argument for attachEvent, or when using inline events.

Inline events (HTML onclick="" property and element.onclick)

In all browsers that support javascript, you can put an event listener inline, meaning right in the HTML code. You've probably seen this:

<a id="testing" href="#" onclick="alert('did stuff inline');">Click me</a>

Most experienced developers shun this method, but it does get the job done; it is simple and direct. You may not use closures or anonymous functions here (though the handler itself is an anonymous function of sorts), and your control of scope is limited.

The other method you mention:

element.onclick = function () { /*do stuff here */ };

... is the equivalent of inline javascript except that you have more control of the scope (since you're writing a script rather than HTML) and can use anonymous functions, function references, and/or closures.

The significant drawback with inline events is that unlike event listeners described above, you may only have one inline event assigned. Inline events are stored as an attribute/property of the element[doc], meaning that it can be overwritten.

Using the example <a> from the HTML above:

var element = document.getElementById('testing');
element.onclick = function () { alert('did stuff #1'); };
element.onclick = function () { alert('did stuff #2'); };

... when you clicked the element, you'd only see "Did stuff #2" - you overwrote the first assigned of the onclick property with the second value, and you overwrote the original inline HTML onclick property too. Check it out here: http://jsfiddle.net/jpgah/.

Broadly speaking, do not use inline events. There may be specific use cases for it, but if you are not 100% sure you have that use case, then you do not and should not use inline events.

Modern Javascript (Angular and the like)

Since this answer was originally posted, javascript frameworks like Angular have become far more popular. You will see code like this in an Angular template:

<button (click)="doSomething()">Do Something</button>

This looks like an inline event, but it isn't. This type of template will be transpiled into more complex code which uses event listeners behind the scenes. Everything I've written about events here still applies, but you are removed from the nitty gritty by at least one layer. You should understand the nuts and bolts, but if your modern JS framework best practices involve writing this kind of code in a template, don't feel like you're using an inline event -- you aren't.

Which is Best?

The question is a matter of browser compatibility and necessity. Do you need to attach more than one event to an element? Will you in the future? Odds are, you will. attachEvent and addEventListener are necessary. If not, an inline event may seem like they'd do the trick, but you're much better served preparing for a future that, though it may seem unlikely, is predictable at least. There is a chance you'll have to move to JS-based event listeners, so you may as well just start there. Don't use inline events.

jQuery and other javascript frameworks encapsulate the different browser implementations of DOM level 2 events in generic models so you can write cross-browser compliant code without having to worry about IE's history as a rebel. Same code with jQuery, all cross-browser and ready to rock:

$(element).on('click', function () { /* do stuff */ });

Don't run out and get a framework just for this one thing, though. You can easily roll your own little utility to take care of the older browsers:

function addEvent(element, evnt, funct){
  if (element.attachEvent)
   return element.attachEvent('on'+evnt, funct);
  else
   return element.addEventListener(evnt, funct, false);
}

// example
addEvent(
    document.getElementById('myElement'),
    'click',
    function () { alert('hi!'); }
);

Try it: http://jsfiddle.net/bmArj/

Taking all of that into consideration, unless the script you're looking at took the browser differences into account some other way (in code not shown in your question), the part using addEventListener would not work in IE versions less than 9.

Documentation and Related Reading

How do I find the size of a struct?

This will vary depending on your architecture and how it treats basic data types. It will also depend on whether the system requires natural alignment.

Delete/Reset all entries in Core Data?

You can still delete the file programmatically, using the NSFileManager:removeItemAtPath:: method.

NSPersistentStore *store = ...;
NSError *error;
NSURL *storeURL = store.URL;
NSPersistentStoreCoordinator *storeCoordinator = ...;
[storeCoordinator removePersistentStore:store error:&error];
[[NSFileManager defaultManager] removeItemAtPath:storeURL.path error:&error];

Then, just add the persistent store back to ensure it is recreated properly.

The programmatic way for iterating through each entity is both slower and prone to error. The use for doing it that way is if you want to delete some entities and not others. However you still need to make sure you retain referential integrity or you won't be able to persist your changes.

Just removing the store and recreating it is both fast and safe, and can certainly be done programatically at runtime.

Update for iOS5+

With the introduction of external binary storage (allowsExternalBinaryDataStorage or Store in External Record File) in iOS 5 and OS X 10.7, simply deleting files pointed by storeURLs is not enough. You'll leave the external record files behind. Since the naming scheme of these external record files is not public, I don't have a universal solution yet. – an0 May 8 '12 at 23:00

How to cherry-pick from a remote branch?

I solved this issue by going on the branch with the commit I want to cherry pick.

git checkout <branch With Commit To Cherry-Pick>

use log to find commit hash

git log

when you've found your hash cut and paste on note pad. if using command just scroll up to get the hash then checkout the branch you want to place the commit in.

git checkout < branch I Want To Place My Cherry-Picked-Hash In>

finally call cherry-pick from git (note) -x is to append your cherry-pick message to the original. "When recording the commit, append a line that says "(cherry picked from commit …?)" to the original commit message in order to indicate which commit this change was cherry-picked from. "

git cherry-pick -x <your hash commit to add to the current branch>

What exceptions should be thrown for invalid or unexpected parameters in .NET?

There is a standard ArgumentException that you could use, or you could subclass and make your own. There are several specific ArgumentException classes:

http://msdn.microsoft.com/en-us/library/system.argumentexception(VS.71).aspx

Whichever one works best.

How to Force New Google Spreadsheets to refresh and recalculate?

File -> Spreadsheet Settings -> (Tab) Calculation -> Recalculation (3 Options)
- On change
- On change and every minute
- On change and every hour
This affects how often NOW, TODAY, RAND, and RANDBETWEEN are updated.

but.. .. it updates only, if the functions arguments (their ranges, cells) are affected by that.

from my example
I use google spreadsheet to find out the age of a person. I have his birthday date in the format (dd.mm.yyyy) -> it's the used format here in Switzerland.

=ARRAYFORMULA(IF(ISTEXT(K4:K), IF(TODAY() - DATE(YEAR(TODAY()), MONTH(REGEXREPLACE(K4:K, "[.]", "/")), DAY(REGEXREPLACE(K4:K, "[.]", "/"))) > 0, YEAR(TODAY()) - YEAR(REGEXREPLACE(K4:K, "[.]", "/")) + 1, YEAR(TODAY()) - YEAR(REGEXREPLACE(K4:K, "[.]", "/"))), IF(LEN(K4:K) > 0, IF(TODAY() - DATE(YEAR(TODAY()), MONTH(K4:K), DAY(K4:K)) > 0, YEAR(TODAY()) - YEAR(K4:K) + 1, YEAR(TODAY()) - YEAR(K4:K)), "")))

I'm using TODAY() and I did the recalculation settings described above. -> but no automatically refresh. :-(
It updates only, if I change some value inside the ranges where the function is looking for.

So I wrote a Google Script (Tools -> Script Editor..) for that purpose.

function onOpen() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheetMaster = ss.getSheetByName("Master"); 
  var sortRange = sheetMaster.getRange(firstRow, firstColumn, lastRow, lastColumn);  

  sortRange.getCell(1, 2).setValue(sortRange.getCell(1, 2).getValue());
}

You need to set numbers for firstRow, firstColumn, lastRow, lastColumn

The Script get active when the spreadsheets open, writes the content of one cell into the same cell again. That's enough to trigger the TODAY() function.

Look for more information on that link from Edward Moffett. Force google sheet formula to recalculate

Best regards,
Christoph

C++ for each, pulling from vector elements

For next examples assumed that you use C++11. Example with ranged-based for loops:

for (auto &attack : m_attack) // access by reference to avoid copying
{  
    if (attack->m_num == input)
    {
        attack->makeDamage();
    }
}

You should use const auto &attack depending on the behavior of makeDamage().

You can use std::for_each from standard library + lambdas:

std::for_each(m_attack.begin(), m_attack.end(),
        [](Attack * attack)
        {
            if (attack->m_num == input)
            {
                attack->makeDamage();
            }
        }
);

If you are uncomfortable using std::for_each, you can loop over m_attack using iterators:

for (auto attack = m_attack.begin(); attack != m_attack.end(); ++attack)
{  
    if (attack->m_num == input)
    {
        attack->makeDamage();
    }
}

Use m_attack.cbegin() and m_attack.cend() to get const iterators.

How to use the "required" attribute with a "radio" input field

TL;DR: Set the required attribute for at least one input of the radio group.

Setting required for all inputs is more clear, but not necessary (unless dynamically generating radio-buttons).

To group radio buttons they must all have the same name value. This allows only one to be selected at a time and applies required to the whole group.

_x000D_

<form>_x000D_
  Select Gender:<br>_x000D_
_x000D_
  <label>_x000D_
    <input type="radio" name="gender" value="male" required>_x000D_
    Male_x000D_
  </label><br>_x000D_
_x000D_
  <label>_x000D_
    <input type="radio" name="gender" value="female">_x000D_
    Female_x000D_
  </label><br>_x000D_
_x000D_
  <label>_x000D_
    <input type="radio" name="gender" value="other">_x000D_
    Other_x000D_
  </label><br>_x000D_
_x000D_
  <input type="submit">_x000D_
</form>

_x000D_

Also take note of:

To avoid confusion as to whether a radio button group is required or not, authors are encouraged to specify the attribute on all the radio buttons in a group. Indeed, in general, authors are encouraged to avoid having radio button groups that do not have any initially checked controls in the first place, as this is a state that the user cannot return to, and is therefore generally considered a poor user interface.

Source

Graph visualization library in JavaScript

Disclaimer: I'm a developer of Cytoscape.js

Cytoscape.js is a HTML5 graph visualisation library. The API is sophisticated and follows jQuery conventions, including

selectors for querying and filtering (cy.elements("node[weight >= 50].someClass") does much as you would expect),
chaining (e.g. cy.nodes().unselect().trigger("mycustomevent")),
jQuery-like functions for binding to events,
elements as collections (like jQuery has collections of HTMLDomElements),
extensibility (can add custom layouts, UI, core & collection functions, and so on),
and more.

If you're thinking about building a serious webapp with graphs, you should at least consider Cytoscape.js. It's free and open-source:

http://js.cytoscape.org

What is the difference between resource and endpoint?

According https://apiblueprint.org/documentation/examples/13-named-endpoints.html is a resource a "general" place of storage of the given entity - e.g. /customers/30654/orders, whereas an endpoint is the concrete action (HTTP Method) over the given resource. So one resource can have multiple endpoints.

JOptionPane YES/No Options Confirm Dialog Box Issue

You need to look at the return value of the call to showConfirmDialog. I.E.:

int dialogResult = JOptionPane.showConfirmDialog (null, "Would You Like to Save your Previous Note First?","Warning",dialogButton);
if(dialogResult == JOptionPane.YES_OPTION){
  // Saving code here
}

You were testing against dialogButton, which you were using to set the buttons that should be displayed by the dialog, and this variable was never updated - so dialogButton would never have been anything other than JOptionPane.YES_NO_OPTION.

Per the Javadoc for showConfirmDialog:

Returns: an integer indicating the option selected by the user

wget command to download a file and save as a different filename

Use the -O file option.

E.g.

wget google.com
...
16:07:52 (538.47 MB/s) - `index.html' saved [10728]

vs.

wget -O foo.html google.com
...
16:08:00 (1.57 MB/s) - `foo.html' saved [10728]

Converting BitmapImage to Bitmap and vice versa

If you just need to go from BitmapImage to Bitmap it's quite easy,

private Bitmap BitmapImage2Bitmap(BitmapImage bitmapImage)
    {
        return new Bitmap(bitmapImage.StreamSource);
    }

Bootstrap Collapse not Collapsing

You need jQuery see bootstrap's basic template

WebAPI Multiple Put/Post parameters

You can get the formdata as string:

    protected NameValueCollection GetFormData()
    {
        string root = HttpContext.Current.Server.MapPath("~/App_Data");
        var provider = new MultipartFormDataStreamProvider(root);

        Request.Content.ReadAsMultipartAsync(provider);

        return provider.FormData;
    }

    [HttpPost]
    public void test() 
    {
        var formData = GetFormData();
        var userId = formData["userId"];

        // todo json stuff
    }

https://docs.microsoft.com/en-us/aspnet/web-api/overview/advanced/sending-html-form-data-part-2

How to use not contains() in xpath?

Should be xpath with not contains() method, //production[not(contains(category,'business'))]

Find where python is installed (if it isn't default dir)

On windows running where python should work.

Convert DateTime to String PHP

There are some predefined formats in date_d.php to use with format like:

define ('DATE_ATOM', "Y-m-d\TH:i:sP");
define ('DATE_COOKIE', "l, d-M-y H:i:s T");
define ('DATE_ISO8601', "Y-m-d\TH:i:sO");
define ('DATE_RFC822', "D, d M y H:i:s O");
define ('DATE_RFC850', "l, d-M-y H:i:s T");
define ('DATE_RFC1036', "D, d M y H:i:s O");
define ('DATE_RFC1123', "D, d M Y H:i:s O");
define ('DATE_RFC2822', "D, d M Y H:i:s O");
define ('DATE_RFC3339', "Y-m-d\TH:i:sP");
define ('DATE_RSS', "D, d M Y H:i:s O");
define ('DATE_W3C', "Y-m-d\TH:i:sP");

Use like this:

$date = new \DateTime();
$string = $date->format(DATE_RFC2822);

How to generate a Makefile with source in sub-directories using just one makefile

Usually, you create a Makefile in each subdirectory, and write in the top-level Makefile to call make in the subdirectories.

This page may help: http://www.gnu.org/software/make/

How to write log base(2) in c/c++

C99 has log2 (as well as log2f and log2l for float and long double).

Selenium Error - The HTTP request to the remote WebDriver timed out after 60 seconds

In my case none of the answers above solved my problem completely. I ended up using the (no-sandbox) mode, the connection with extended timeout period (driver = new RemoteWebDriver(new Uri("http://localhost:4444/wd/hub"), capability, TimeSpan.FromMinutes(3));) and the page load timeout (driver.Manage().Timeouts().PageLoad.Add(System.TimeSpan.FromSeconds(30));) so now my code looks like this:

    public IWebDriver GetRemoteChromeDriver(string downloadPath)
    {
        ChromeOptions chromeOptions = new ChromeOptions();
        chromeOptions.AddArguments(
            "start-maximized",
            "enable-automation",
            "--headless",
            "--no-sandbox", //this is the relevant other arguments came from solving other issues
            "--disable-infobars",
            "--disable-dev-shm-usage",
            "--disable-browser-side-navigation",
            "--disable-gpu",
            "--ignore-certificate-errors");
        capability = chromeOptions.ToCapabilities();

        SetRemoteWebDriver();
        SetImplicitlyWait();
        Thread.Sleep(TimeSpan.FromSeconds(2));
        return driver;
    }
    
    private void SetImplicitlyWait()
    {
        driver.Manage().Timeouts().PageLoad.Add(TimeSpan.FromSeconds(30));
    }


    private void SetRemoteWebDriver()
    {
        driver = new RemoteWebDriver(new Uri("http://localhost:4444/wd/hub"), capability, TimeSpan.FromMinutes(3));
    }

But as I mentioned none of the above method solved my problem, I was continuously get the error, and multiple chromedriver.exe and chrome.exe processses were active (~10 of the chromedriver and ~50 of chrome).

So somewhere I read that after disposing the driver I should wait a few seconds before starting the next test, so I added the following line to dispose method:

    driver?.Quit();
    driver?.Dispose();
    Thread.Sleep(3000);

With this sleep modification I have no longer get the timeout error and there is no unnecessarily opened chromedriver.exe and chrome.exe processses.

I hope I helped someone who struggles with this issue for that long as I did.

New features in java 7

The following list contains links to the the enhancements pages in the Java SE 7.

Swing
IO and New IO
Networking
Security
Concurrency Utilities
Rich Internet Applications (RIA)/Deployment
    Requesting and Customizing Applet Decoration in Dragg able Applets
    Embedding JNLP File in Applet Tag
    Deploying without Codebase
    Handling Applet Initialization Status with Event Handlers
Java 2D
Java XML – JAXP, JAXB, and JAX-WS
Internationalization
java.lang Package
    Multithreaded Custom Class Loaders in Java SE 7
Java Programming Language
    Binary Literals
    Strings in switch Statements
    The try-with-resources Statement
    Catching Multiple Exception Types and Rethrowing Exceptions with Improved Type Checking
    Underscores in Numeric Literals
    Type Inference for Generic Instance Creation
    Improved Compiler Warnings and Errors When Using Non-Reifiable Formal Parameters with Varargs Methods
Java Virtual Machine (JVM)
    Java Virtual Machine Support for Non-Java Languages
    Garbage-First Collector
    Java HotSpot Virtual Machine Performance Enhancements
JDBC

Reference 1 Reference 2

PHP compare two arrays and get the matched values not the difference

OK.. We needed to compare a dynamic number of product names...

There's probably a better way... but this works for me...

... because....Strings are just Arrays of characters.... :>}

//  Compare Strings ...  Return Matching Text and Differences with Product IDs...

//  From MySql...
$productID1 = 'abc123';
$productName1 = "EcoPlus Premio Jet 600";   

$productID2 = 'xyz789';
$productName2 = "EcoPlus Premio Jet 800";   

$ProductNames = array(
    $productID1 => $productName1,
    $productID2 => $productName2
);


function compareNames($ProductNames){   

    //  Convert NameStrings to Arrays...    
    foreach($ProductNames as $id => $product_name){
        $Package1[$id] = explode(" ",$product_name);    
    }

    // Get Matching Text...
    $Matching = call_user_func_array('array_intersect', $Package1 );
    $MatchingText = implode(" ",$Matching);

    //  Get Different Text...
    foreach($Package1 as $id => $product_name_chunks){
        $Package2 = array($product_name_chunks,$Matching);
        $diff = call_user_func_array('array_diff', $Package2 );
        $DifferentText[$id] = trim(implode(" ", $diff));
    }

    $results[$MatchingText]  = $DifferentText;              
    return $results;    
}

$Results =  compareNames($ProductNames);

print_r($Results);

// Gives us this...
[EcoPlus Premio Jet] 
        [abc123] => 600
        [xyz789] => 800

How to reverse apply a stash?

This is in addition to the above answers but adds search for the git stash based on the message as the stash number can change when new stashes are saved. I have written a couple of bash functions:

apply(){
  if [ "$1" ]; then
    git stash apply `git stash list | grep -oPm1 "(.*)(?=:.*:.*$1.*)"`
  fi
}
remove(){
  if [ "$1" ]; then
    git stash show -p `git stash list | grep -oPm1 "(.*)(?=:.*:.*$1.*)"` | git apply -R
    git status
  fi
}

Create stash with name (message) $ git stash save "my stash"
To appply named $ apply "my stash"
To remove named stash $ remove "my stash"

JS strings "+" vs concat method

We can't concatenate a string variable to an integer variable using concat() function because this function only applies to a string, not on a integer. but we can concatenate a string to a number(integer) using + operator.
As we know, functions are pretty slower than operators. functions needs to pass values to the predefined functions and need to gather the results of the functions. which is slower than doing operations using operators because operators performs operations in-line but, functions used to jump to appropriate memory locations... So, As mentioned in previous answers the other difference is obviously the speed of operation.

_x000D_

<!DOCTYPE html>_x000D_
<html>_x000D_
<body>_x000D_
_x000D_
<p>The concat() method joins two or more strings</p>_x000D_
_x000D_
_x000D_
<p id="demo"></p>_x000D_
<p id="demo1"></p>_x000D_
_x000D_
<script>_x000D_
var text1 = 4;_x000D_
var text2 = "World!";_x000D_
document.getElementById("demo").innerHTML = text1 + text2;_x000D_
//Below Line can't produce result_x000D_
document.getElementById("demo1").innerHTML = text1.concat(text2);_x000D_
</script>_x000D_
<p><strong>The Concat() method can't concatenate a string with a integer </strong></p>_x000D_
</body>_x000D_
</html>

_x000D_

jQuery append() - return appended elements

A little reminder, when elements are added dynamically, functions like append(), appendTo(), prepend() or prependTo() return a jQuery object, not the HTML DOM element.

DEMO

var container=$("div.container").get(0),
    htmlA="<div class=children>A</div>",
    htmlB="<div class=children>B</div>";

// jQuery object
alert( $(container).append(htmlA) ); // outputs "[object Object]"

// HTML DOM element
alert( $(container).append(htmlB).get(0) ); // outputs "[object HTMLDivElement]"

Intent from Fragment to Activity

Remove this

android:onClick="goToAttract"

Then

View rootView = inflater.inflate(R.layout.fragment_home, container, false);
Button b = (Button)rootView.findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener()
{
     public void onClick(View v)
     {
        Intent intent = new Intent(getActivity(), MainActivityList.class);
        startActivity(intent);

     } 

});
return rootView;

The error says you need to public void goToAttract(View v) in Activity class

Could not find method goToAttract(View) in the activity class

Reason pls check the answer by PareshMayani @

Android app crashing (fragment and xml onclick)

Edit:

Caused by: java.lang.OutOfMemoryError

I guess you have a image that is too big to fit in and it needs to be scaled down. Hence the OutOfMemoryError.

Horizontal Scroll Table in Bootstrap/CSS

@Ciwan. You're right. The table goes to full width (much too wide). Not a good solution. Better to do this:

css:

.scrollme {
    overflow-x: auto;
}

html:

<div class="scrollme">                        
  <table class="table table-responsive"> ...
  </table>
</div>

Edit: changing scroll-y to scroll-x

Removing array item by value

I am adding a second answer. I wrote a quick benchmarking script to try various methods here.

$arr = array(0 => 123456);
for($i = 1; $i < 500000; $i++) {
    $arr[$i] = rand(0,PHP_INT_MAX);
}

shuffle($arr);
$arr2 = $arr;
$arr3 = $arr;

/** 
 * Method 1 - array_search()
 */
$start = microtime(true);
while(($key = array_search(123456,$arr)) !== false) {
    unset($arr[$key]);
}
echo count($arr). ' left, in '.(microtime(true) - $start).' seconds<BR>';

/** 
 * Method 2 - basic loop
 */
$start = microtime(true);
foreach($arr2 as $k => $v) {
    if ($v == 123456) {
        unset($arr2[$k]);
    }
}
echo count($arr2). 'left, in '.(microtime(true) - $start).' seconds<BR>';

/** 
 * Method 3 - array_keys() with search parameter
 */
$start = microtime(true);
$keys = array_keys($arr3,123456);
foreach($keys as $k) {
    unset($arr3[$k]);
}
echo count($arr3). 'left, in '.(microtime(true) - $start).' seconds<BR>';

The third method, array_keys() with the optional search parameter specified, seems to be by far the best method. Output example:

499999 left, in 0.090957164764404 seconds
499999left, in 0.43156313896179 seconds
499999left, in 0.028877019882202 seconds

Judging by this, the solution I would use then would be:

$keysToRemove = array_keys($items,$id);
foreach($keysToRemove as $k) {
    unset($items[$k]);
}

How to find EOF through fscanf?

If you have integers in your file fscanf returns 1 until integer occurs. For example:

FILE *in = fopen("./task.in", "r");
int length = 0;
int counter;
int sequence;

for ( int i = 0; i < 10; i++ ) {
    counter = fscanf(in, "%d", &sequence);
    if ( counter == 1 ) {
        length += 1;
    }
}

To find out the end of the file with symbols you can use EOF. For example:

char symbol;
FILE *in = fopen("./task.in", "r");

for ( ; fscanf(in, "%c", &symbol) != EOF; ) {
    printf("%c", symbol); 
}

Global constants file in Swift

Swift 4 Version

If you want to create a name for NotificationCenter:

extension Notification.Name {
    static let updateDataList1 = Notification.Name("updateDataList1")
}

Subscribe to notifications:

NotificationCenter.default.addObserver(self, selector: #selector(youFunction), name: .updateDataList1, object: nil)

Send notification:

NotificationCenter.default.post(name: .updateDataList1, object: nil)

If you just want a class with variables to use:

class Keys {
    static let key1 = "YOU_KEY"
    static let key2 = "YOU_KEY"
}

Or:

struct Keys {
    static let key1 = "YOU_KEY"
    static let key2 = "YOU_KEY"
}

How do I get a reference to the app delegate in Swift?

extension AppDelegate {

    // MARK: - App Delegate Ref
    class func delegate() -> AppDelegate {
        return UIApplication.shared.delegate as! AppDelegate
    }
}

Paging with Oracle

Just want to summarize the answers and comments. There are a number of ways doing a pagination.

Prior to oracle 12c there were no OFFSET/FETCH functionality, so take a look at whitepaper as the @jasonk suggested. It's the most complete article I found about different methods with detailed explanation of advantages and disadvantages. It would take a significant amount of time to copy-paste them here, so I won't do it.

There is also a good article from jooq creators explaining some common caveats with oracle and other databases pagination. jooq's blogpost

Good news, since oracle 12c we have a new OFFSET/FETCH functionality. OracleMagazine 12c new features. Please refer to "Top-N Queries and Pagination"

You may check your oracle version by issuing the following statement

SELECT * FROM V$VERSION

What exactly does Double mean in java?

In a comment on @paxdiablo's answer, you asked:

"So basically, is it better to use Double than Float?"

That is a complicated question. I will deal with it in two parts

Deciding between `double` versus `float`

On the one hand, a double occupies 8 bytes versus 4 bytes for a float. If you have many of them, this may be significant, though it may also have no impact. (Consider the case where the values are in fields or local variables on a 64bit machine, and the JVM aligns them on 64 bit boundaries.) Additionally, floating point arithmetic with double values is typically slower than with float values ... though once again this is hardware dependent.

On the other hand, a double can represent larger (and smaller) numbers than a float and can represent them with more than twice the precision. For the details, refer to Wikipedia.

The tricky question is knowing whether you actually need the extra range and precision of a double. In some cases it is obvious that you need it. In others it is not so obvious. For instance if you are doing calculations such as inverting a matrix or calculating a standard deviation, the extra precision may be critical. On the other hand, in some cases not even double is going to give you enough precision. (And beware of the trap of expecting float and double to give you an exact representation. They won't and they can't!)

There is a branch of mathematics called Numerical Analysis that deals with the effects of rounding error, etc in practical numerical calculations. It used to be a standard part of computer science courses ... back in the 1970's.

Deciding between `Double` versus `Float`

For the Double versus Float case, the issues of precision and range are the same as for double versus float, but the relative performance measures will be slightly different.

A Double (on a 32 bit machine) typically takes 16 bytes + 4 bytes for the reference, compared with 12 + 4 bytes for a Float. Compare this to 8 bytes versus 4 bytes for the double versus float case. So the ratio is 5 to 4 versus 2 to 1.
Arithmetic involving Double and Float typically involves dereferencing the pointer and creating a new object to hold the result (depending on the circumstances). These extra overheads also affect the ratios in favor of the Double case.

Correctness

Having said all that, the most important thing is correctness, and this typically means getting the most accurate answer. And even if accuracy is not critical, it is usually not wrong to be "too accurate". So, the simple "rule of thumb" is to use double in preference to float, UNLESS there is an overriding performance requirement, AND you have solid evidence that using float will make a difference with respect to that requirement.

Wpf DataGrid Add new row

Try this MSDN blog

Also, try the following example:

Xaml:

   <DataGrid AutoGenerateColumns="False" Name="DataGridTest" CanUserAddRows="True" ItemsSource="{Binding TestBinding}" Margin="0,50,0,0" >
        <DataGrid.Columns>
            <DataGridTextColumn Header="Line" IsReadOnly="True" Binding="{Binding Path=Test1}" Width="50"></DataGridTextColumn>
            <DataGridTextColumn Header="Account" IsReadOnly="True"  Binding="{Binding Path=Test2}" Width="130"></DataGridTextColumn>
        </DataGrid.Columns>
    </DataGrid>
    <Button Content="Add new row" HorizontalAlignment="Left" Margin="0,10,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click_1"/>

CS:

 /// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private void Button_Click_1(object sender, RoutedEventArgs e)
    {
        var data = new Test { Test1 = "Test1", Test2 = "Test2" };

        DataGridTest.Items.Add(data);
    }
}

public class Test
{
    public string Test1 { get; set; }
    public string Test2 { get; set; }
}

good postgresql client for windows?

SQLExplorer is a great Eclipse plugin or standalone interface that works with many different database systems, either with dedicated drivers or with ODBC.

Check if application is installed - Android

Since Android 11 (API level 30), most user-installed apps are not visible by default. In your manifest, you must statically declare which apps you are going to get info about, as in the following:

<manifest>
    <queries>
        <!-- Explicit apps you know in advance about: -->
        <package android:name="com.example.this.app"/>
        <package android:name="com.example.this.other.app"/>
    </queries>
    
    ...
</manifest>

Then, @RobinKanters' answer works:

private boolean isPackageInstalled(String packageName, PackageManager packageManager) {
    try {
        packageManager.getPackageInfo(packageName, 0);
        return true;
    } catch (PackageManager.NameNotFoundException e) {
        return false;
    }
}

// ...
// This will return true on Android 11 if the app is installed,
// since we declared it above in the manifest.
isPackageInstalled("com.example.this.app", pm); 
// This will return false on Android 11 even if the app is installed:
isPackageInstalled("another.random.app", pm);

Learn more here:

How can I disable all views inside the layout?

My two cents function without recursion

    package io.chord.ui.utils

import android.view.View
import android.view.ViewGroup
import androidx.core.view.forEach

class ViewUtils
{
    companion object
    {
        fun setViewState(view: View, state: Boolean)
        {
            var depth = 0
            val views: MutableMap<Int, MutableList<View>> = mutableMapOf()
            views[depth] = mutableListOf(view)

            while(true)
            {
                val currentViews = views[depth]
                val nextViews = mutableListOf<View>()

                currentViews!!.forEach { view ->
                    if(view is ViewGroup)
                    {
                        view.forEach { children ->
                            nextViews.add(children)
                        }
                    }
                }

                if(nextViews.size == 0)
                {
                    break
                }

                depth++

                views[depth] = nextViews
            }

            views.flatMap {
                it.value
            }.forEach {
                it.isEnabled = state
            }
        }
    }
}

How to install GCC piece by piece with GMP, MPFR, MPC, ELF, without shared libraries?

How to move files using FTP commands

async await return Task

Adding the async keyword is just syntactic sugar to simplify the creation of a state machine. In essence, the compiler takes your code;

public async Task MethodName()
{
     return null;
}

And turns it into;

public Task MethodName()
{
     return Task.FromResult<object>(null);
}

If your code has any await keywords, the compiler must take your method and turn it into a class to represent the state machine required to execute it. At each await keyword, the state of variables and the stack will be preserved in the fields of the class, the class will add itself as a completion hook to the task you are waiting on, then return.

When that task completes, your task will be executed again. So some extra code is added to the top of the method to restore the state of variables and jump into the next slab of your code.

See What does async & await generate? for a gory example.

This process has a lot in common with the way the compiler handles iterator methods with yield statements.

Iterator Loop vs index loop

By writing your client code in terms of iterators you abstract away the container completely.

Consider this code:

class ExpressionParser // some generic arbitrary expression parser
{
public:
    template<typename It>
    void parse(It begin, const It end)
    {
        using namespace std;
        using namespace std::placeholders;
        for_each(begin, end, 
            bind(&ExpressionParser::process_next, this, _1);
    }
    // process next char in a stream (defined elsewhere)
    void process_next(char c);
};

client code:

ExpressionParser p;

std::string expression("SUM(A) FOR A in [1, 2, 3, 4]");
p.parse(expression.begin(), expression.end());

std::istringstream file("expression.txt");
p.parse(std::istringstream<char>(file), std::istringstream<char>());

char expr[] = "[12a^2 + 13a - 5] with a=108";
p.parse(std::begin(expr), std::end(expr));

Edit: Consider your original code example, implemented with :

using namespace std;

vector<int> myIntVector;
// Add some elements to myIntVector
myIntVector.push_back(1);
myIntVector.push_back(4);
myIntVector.push_back(8);

copy(myIntVector.begin(), myIntVector.end(), 
    std::ostream_iterator<int>(cout, " "));

GZIPInputStream reading line by line

BufferedReader in = new BufferedReader(new InputStreamReader(
        new GZIPInputStream(new FileInputStream("F:/gawiki-20090614-stub-meta-history.xml.gz"))));

String content;

while ((content = in.readLine()) != null)

   System.out.println(content);

How to set recurring schedule for xlsm file using Windows Task Scheduler

I found a much easier way and I hope it works for you. (using Windows 10 and Excel 2016)

Create a new module and enter the following code: Sub auto_open() 'Macro to be run (doesn't have to be in this module, just in this workbook End Sub

Set up a task through the Task Scheduler and set the "program to be run as" Excel (found mine at C:\Program Files (x86)\Microsoft Office\root\Office16). Then set the "Add arguments (optional): as the file path to the macro-enabled workbook. Remember that both the path to Excel and the path to the workbook should be in double quotes.

*See example from Rich, edited by Community, for an image of the windows scheduler screen.

JPQL IN clause: Java-Arrays (or Lists, Sets...)?

I'm not sure for JPA 1.0 but you can pass a Collection in JPA 2.0:

String qlString = "select item from Item item where item.name IN :names"; 
Query q = em.createQuery(qlString, Item.class);

List<String> names = Arrays.asList("foo", "bar");

q.setParameter("names", names);
List<Item> actual = q.getResultList();

assertNotNull(actual);
assertEquals(2, actual.size());

Tested with EclipseLInk. With Hibernate 3.5.1, you'll need to surround the parameter with parenthesis:

String qlString = "select item from Item item where item.name IN (:names)";

But this is a bug, the JPQL query in the previous sample is valid JPQL. See HHH-5126.

How to properly overload the << operator for an ostream?

Just telling you about one other possibility: I like using friend definitions for that:

namespace Math
{
    class Matrix
    {
    public:

        [...]

        friend std::ostream& operator<< (std::ostream& stream, const Matrix& matrix) {
            [...]
        }
    };
}

The function will be automatically targeted into the surrounding namespace Math (even though its definition appears within the scope of that class) but will not be visible unless you call operator<< with a Matrix object which will make argument dependent lookup find that operator definition. That can sometimes help with ambiguous calls, since it's invisible for argument types other than Matrix. When writing its definition, you can also refer directly to names defined in Matrix and to Matrix itself, without qualifying the name with some possibly long prefix and providing template parameters like Math::Matrix<TypeA, N>.

Mocking a function to raise an Exception to test an except block

Your mock is raising the exception just fine, but the error.resp.status value is missing. Rather than use return_value, just tell Mock that status is an attribute:

barMock.side_effect = HttpError(mock.Mock(status=404), 'not found')

Additional keyword arguments to Mock() are set as attributes on the resulting object.

I put your foo and bar definitions in a my_tests module, added in the HttpError class so I could use it too, and your test then can be ran to success:

>>> from my_tests import foo, HttpError
>>> import mock
>>> with mock.patch('my_tests.bar') as barMock:
...     barMock.side_effect = HttpError(mock.Mock(status=404), 'not found')
...     result = my_test.foo()
... 
404 - 
>>> result is None
True

You can even see the print '404 - %s' % error.message line run, but I think you wanted to use error.content there instead; that's the attribute HttpError() sets from the second argument, at any rate.

How to center the text in PHPExcel merged cell

We can also set the vertical alignment with using this way

$style_cell = array(
   'alignment' => array(
       'horizontal' => PHPExcel_Style_Alignment::HORIZONTAL_CENTER,
       'vertical' => PHPExcel_Style_Alignment::VERTICAL_CENTER,
   ) 
);

with this cell set the vertically aligned into the middle.

Writing data to a local text file with javascript

Our HTML:

<div id="addnew">
    <input type="text" id="id">
    <input type="text" id="content">
    <input type="button" value="Add" id="submit">
</div>

<div id="check">
    <input type="text" id="input">
    <input type="button" value="Search" id="search">
</div>

JS (writing to the txt file):

function writeToFile(d1, d2){
    var fso = new ActiveXObject("Scripting.FileSystemObject");
    var fh = fso.OpenTextFile("data.txt", 8, false, 0);
    fh.WriteLine(d1 + ',' + d2);
    fh.Close();
}
var submit = document.getElementById("submit");
submit.onclick = function () {
    var id      = document.getElementById("id").value;
    var content = document.getElementById("content").value;
    writeToFile(id, content);
}

checking a particular row:

function readFile(){
    var fso = new ActiveXObject("Scripting.FileSystemObject");
    var fh = fso.OpenTextFile("data.txt", 1, false, 0);
    var lines = "";
    while (!fh.AtEndOfStream) {
        lines += fh.ReadLine() + "\r";
    }
    fh.Close();
    return lines;
}
var search = document.getElementById("search");
search.onclick = function () {
    var input   = document.getElementById("input").value;
    if (input != "") {
        var text    = readFile();
        var lines   = text.split("\r");
        lines.pop();
        var result;
        for (var i = 0; i < lines.length; i++) {
            if (lines[i].match(new RegExp(input))) {
                result = "Found: " + lines[i].split(",")[1];
            }
        }
        if (result) { alert(result); }
        else { alert(input + " not found!"); }
    }
}

Put these inside a .hta file and run it. Tested on W7, IE11. It's working. Also if you want me to explain what's going on, say so.

How to identify and switch to the frame in selenium webdriver when frame does not have id

Make sure you switch to default content before switching to frame:

driver.switchTo().defaultContent();
driver.switchTo().frame(x);

x can be the frame number or you can do a driver.findlement and use any of the options you have available eg: driver.findElementByName("Name").

How to create materialized views in SQL Server?

You might need a bit more background on what a Materialized View actually is. In Oracle these are an object that consists of a number of elements when you try to build it elsewhere.

An MVIEW is essentially a snapshot of data from another source. Unlike a view the data is not found when you query the view it is stored locally in a form of table. The MVIEW is refreshed using a background procedure that kicks off at regular intervals or when the source data changes. Oracle allows for full or partial refreshes.

In SQL Server, I would use the following to create a basic MVIEW to (complete) refresh regularly.

First, a view. This should be easy for most since views are quite common in any database Next, a table. This should be identical to the view in columns and data. This will store a snapshot of the view data. Then, a procedure that truncates the table, and reloads it based on the current data in the view. Finally, a job that triggers the procedure to start it's work.

Everything else is experimentation.

Android overlay a view ontop of everything?

I have tried the awnsers before but this did not work. Now I jsut used a LinearLayout instead of a TextureView, now it is working without any problem. Hope it helps some others who have the same problem. :)

    view = (LinearLayout) findViewById(R.id.view); //this is initialized in the constructor
    openWindowOnButtonClick();

public void openWindowOnButtonClick()
{
    view.setAlpha((float)0.5);
    FloatingActionButton fb = (FloatingActionButton) findViewById(R.id.floatingActionButton);
    final InputMethodManager keyboard = (InputMethodManager) getSystemService(getBaseContext().INPUT_METHOD_SERVICE);
    fb.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            // check if the Overlay should be visible. If this value is false, it is not shown -> show it.
            if(view.getVisibility() == View.INVISIBLE)
            {
                view.setVisibility(View.VISIBLE);
                keyboard.toggleSoftInput(InputMethodManager.SHOW_IMPLICIT, 0);
                Log.d("Overlay", "Klick");
            }
            else if(view.getVisibility() == View.VISIBLE)
            {
                view.setVisibility(View.INVISIBLE);
                keyboard.toggleSoftInput(0, InputMethodManager.HIDE_IMPLICIT_ONLY);
            }

Convert bytes to bits in python

Another way to do this is by using the bitstring module:

>>> from bitstring import BitArray
>>> input_str = '0xff'
>>> c = BitArray(hex=input_str)
>>> c.bin
'0b11111111'

And if you need to strip the leading 0b:

>>> c.bin[2:]
'11111111'

The bitstring module isn't a requirement, as jcollado's answer shows, but it has lots of performant methods for turning input into bits and manipulating them. You might find this handy (or not), for example:

>>> c.uint
255
>>> c.invert()
>>> c.bin[2:]
'00000000'

etc.

Remove the title bar in Windows Forms

You can set the Property FormBorderStyle to none in the designer, or in code:

this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;

How do I detect whether 32-bit Java is installed on x64 Windows, only looking at the filesystem and registry?

If it is not Oracle's Java, you may not be able to tell. When I install Oracle Java 64-bit, the files go into C:\Program Files\Java, but when I install a 32-bit version, they default to C:\Program Files (x86)\Java instead. Of course, the person who installed Java could have overridden those defaults.

Windows recursive grep command-line

Recursive search for import word inside src folder:

> findstr /s import .\src\*

cv2.imshow command doesn't work properly in opencv-python

You've got all the necessary pieces somewhere in this thread:

if cv2.waitKey(): cv2.destroyAllWindows()

works fine for me in IDLE.

Alternative to google finance api

If you are still looking to use Google Finance for your data you can check this out.

I recently needed to test if SGX data is indeed retrievable via google finance (and of course i met with the same problem as you)

How to find out the MySQL root password

Go to phpMyAdmin > config.inc.php > $cfg['Servers'][$i]['password'] = '';

Where is my m2 folder on Mac OS X Mavericks

On the top of the screen you can find the Finder. Click Go -> Go to Folder -> search ~/.m2

If it is not found, as m2 is a hidden file you need to enable visibility by typing the following command in terminal:

defaults write com.apple.finder AppleShowAllFiles YES

Google Play on Android 4.0 emulator

You could download it from a Android 4.0 phone and then mount the system image rw and copy it over.

Didnt tried it before but it should work.

How to make JQuery-AJAX request synchronous

From jQuery.ajax()

async Boolean
Default: true
By default, all requests are sent asynchronously (i.e. this is set to true by default). If you need synchronous requests, set this option to false.

So in your request, you must do async: false instead of async: "false".

Update:

The return value of ajaxSubmit is not the return value of the success: function(){...}. ajaxSubmit returns no value at all, which is equivalent to undefined, which in turn evaluates to true.

And that is the reason, why the form is always submitted and is independent of sending the request synchronous or not.

If you want to submit the form only, when the response is "Successful", you must return false from ajaxSubmit and then submit the form in the success function, as @halilb already suggested.

Something along these lines should work

function ajaxSubmit() {
    var password = $.trim($('#employee_password').val());
    $.ajax({
        type: "POST",
        url: "checkpass.php",
        data: "password="+password,
        success: function(response) {
            if(response == "Successful")
            {
                $('form').removeAttr('onsubmit'); // prevent endless loop
                $('form').submit();
            }
        }
    });

    return false;
}

What is the difference between 'classic' and 'integrated' pipeline mode in IIS7?

IIS 6.0 and previous versions :

ASP.NET integrated with IIS via an ISAPI extension, a C API ( C Programming language based API ) and exposed its own application and request processing model.

This effectively exposed two separate server( request / response ) pipelines, one for native ISAPI filters and extension components, and another for managed application components. ASP.NET components would execute entirely inside the ASP.NET ISAPI extension bubble AND ONLY for requests mapped to ASP.NET in the IIS script map configuration.

Requests to non ASP.NET content types:- images, text files, HTML pages, and script-less ASP pages, were processed by IIS or other ISAPI extensions and were NOT visible to ASP.NET.

The major limitation of this model was that services provided by ASP.NET modules and custom ASP.NET application code were NOT available to non ASP.NET requests

What's a SCRIPT MAP ?

Script maps are used to associate file extensions with the ISAPI handler that executes when that file type is requested. The script map also has an optional setting that verifies that the physical file associated with the request exists before allowing the request to be processed

A good example can be seen here

IIS 7 and above

IIS 7.0 and above have been re-engineered from the ground up to provide a brand new C++ API based ISAPI.

IIS 7.0 and above integrates the ASP.NET runtime with the core functionality of the Web Server, providing a unified(single) request processing pipeline that is exposed to both native and managed components known as modules ( IHttpModules )

What this means is that IIS 7 processes requests that arrive for any content type, with both NON ASP.NET Modules / native IIS modules and ASP.NET modules providing request processing in all stages This is the reason why NON ASP.NET content types (.html, static files ) can be handled by .NET modules.

You can build new managed modules (IHttpModule) that have the ability to execute for all application content, and provided an enhanced set of request processing services to your application.
Add new managed Handlers ( IHttpHandler)

How can I open two pages from a single click without using JavaScript?

If you have the authority to edit the pages to be opened, you can href to 'A' page and in the A page you can put link to B page in onpageload attribute of body tag.

Format Instant to String

public static void main(String[] args) {

    DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
            .withZone(ZoneId.systemDefault());

    System.out.println(DATE_TIME_FORMATTER.format(new Date().toInstant()));

}

How to kill a thread instantly in C#?

You should first have some agreed method of ending the thread. For example a running_ valiable that the thread can check and comply with.

Your main thread code should be wrapped in an exception block that catches both ThreadInterruptException and ThreadAbortException that will cleanly tidy up the thread on exit.

In the case of ThreadInterruptException you can check the running_ variable to see if you should continue. In the case of the ThreadAbortException you should tidy up immediately and exit the thread procedure.

The code that tries to stop the thread should do the following:

running_ = false;
threadInstance_.Interrupt();
if(!threadInstance_.Join(2000)) { // or an agreed resonable time
   threadInstance_.Abort();
}

How do I generate a random number between two variables that I have stored?

If you have a C++11 compiler you can prepare yourself for the future by using c++'s pseudo random number faculties:

//make sure to include the random number generators and such
#include <random>
//the random device that will seed the generator
std::random_device seeder;
//then make a mersenne twister engine
std::mt19937 engine(seeder());
//then the easy part... the distribution
std::uniform_int_distribution<int> dist(min, max);
//then just generate the integer like this:
int compGuess = dist(engine);

That might be slightly easier to grasp, being you don't have to do anything involving modulos and crap... although it requires more code, it's always nice to know some new C++ stuff...

Hope this helps - Luke

How to square or raise to a power (elementwise) a 2D numpy array?

>>> import numpy
>>> print numpy.power.__doc__

power(x1, x2[, out])

First array elements raised to powers from second array, element-wise.

Raise each base in `x1` to the positionally-corresponding power in
`x2`.  `x1` and `x2` must be broadcastable to the same shape.

Parameters
----------
x1 : array_like
    The bases.
x2 : array_like
    The exponents.

Returns
-------
y : ndarray
    The bases in `x1` raised to the exponents in `x2`.

Examples
--------
Cube each element in a list.

>>> x1 = range(6)
>>> x1
[0, 1, 2, 3, 4, 5]
>>> np.power(x1, 3)
array([  0,   1,   8,  27,  64, 125])

Raise the bases to different exponents.

>>> x2 = [1.0, 2.0, 3.0, 3.0, 2.0, 1.0]
>>> np.power(x1, x2)
array([  0.,   1.,   8.,  27.,  16.,   5.])

The effect of broadcasting.

>>> x2 = np.array([[1, 2, 3, 3, 2, 1], [1, 2, 3, 3, 2, 1]])
>>> x2
array([[1, 2, 3, 3, 2, 1],
       [1, 2, 3, 3, 2, 1]])
>>> np.power(x1, x2)
array([[ 0,  1,  8, 27, 16,  5],
       [ 0,  1,  8, 27, 16,  5]])
>>>

Precision

As per the discussed observation on numerical precision as per @GarethRees objection in comments:

>>> a = numpy.ones( (3,3), dtype = numpy.float96 ) # yields exact output
>>> a[0,0] = 0.46002700024131926
>>> a
array([[ 0.460027,  1.0,  1.0],
       [ 1.0,  1.0,  1.0],
       [ 1.0,  1.0,  1.0]], dtype=float96)
>>> b = numpy.power( a, 2 )
>>> b
array([[ 0.21162484,  1.0,  1.0],
       [ 1.0,  1.0,  1.0],
       [ 1.0,  1.0,  1.0]], dtype=float96)

>>> a.dtype
dtype('float96')
>>> a[0,0]
0.46002700024131926
>>> b[0,0]
0.21162484095102677

>>> print b[0,0]
0.211624840951
>>> print a[0,0]
0.460027000241

Performance

>>> c    = numpy.random.random( ( 1000, 1000 ) ).astype( numpy.float96 )

>>> import zmq
>>> aClk = zmq.Stopwatch()

>>> aClk.start(), c**2, aClk.stop()
(None, array([[ ...]], dtype=float96), 5663L)                #   5 663 [usec]

>>> aClk.start(), c*c, aClk.stop()
(None, array([[ ...]], dtype=float96), 6395L)                #   6 395 [usec]

>>> aClk.start(), c[:,:]*c[:,:], aClk.stop()
(None, array([[ ...]], dtype=float96), 6930L)                #   6 930 [usec]

>>> aClk.start(), c[:,:]**2, aClk.stop()
(None, array([[ ...]], dtype=float96), 6285L)                #   6 285 [usec]

>>> aClk.start(), numpy.power( c, 2 ), aClk.stop()
(None, array([[ ... ]], dtype=float96), 384515L)             # 384 515 [usec]

How do I configure php to enable pdo and include mysqli on CentOS?

You might just have to install the packages.

yum install php-pdo php-mysqli

After they're installed, restart Apache.

httpd restart

apachectl restart

How to position a CSS triangle using ::after?

You can set triangle with position see this code for reference

.top-left-corner {
    width: 0px;
    height: 0px;
    border-top: 0px solid transparent;
    border-bottom: 55px solid transparent;
    border-left: 55px solid #289006;
    position: absolute;
    left: 0px;
    top: 0px;
}

Add up a column of numbers at the Unix shell

The whole ls -l and then cut is rather convoluted when you have stat. It is also vulnerable to the exact format of ls -l (it didn't work until I changed the column numbers for cut)

Also, fixed the useless use of cat.

<files.txt  xargs stat -c %s | paste -sd+ - | bc

Makefile, header dependencies

As I posted here gcc can create dependencies and compile at the same time:

DEPS := $(OBJS:.o=.d)

-include $(DEPS)

%.o: %.c
    $(CC) $(CFLAGS) -MM -MF $(patsubst %.o,%.d,$@) -o $@ $<

The '-MF' parameter specifies a file to store the dependencies in.

The dash at the start of '-include' tells Make to continue when the .d file doesn't exist (e.g. on first compilation).

Note there seems to be a bug in gcc regarding the -o option. If you set the object filename to say obj/_file__c.o then the generated file.d will still contain file.o, not obj/_file__c.o.

Shell script not running, command not found

#! /bin/bash
  ^---

remove the indicated space. The shebang should be

#!/bin/bash

How to process SIGTERM signal gracefully?

First, I'm not certain that you need a second thread to set the shutdown_flag.
Why not set it directly in the SIGTERM handler?

An alternative is to raise an exception from the SIGTERM handler, which will be propagated up the stack. Assuming you've got proper exception handling (e.g. with with/contextmanager and try: ... finally: blocks) this should be a fairly graceful shutdown, similar to if you were to Ctrl+C your program.

Example program signals-test.py:

#!/usr/bin/python

from time import sleep
import signal
import sys


def sigterm_handler(_signo, _stack_frame):
    # Raises SystemExit(0):
    sys.exit(0)

if sys.argv[1] == "handle_signal":
    signal.signal(signal.SIGTERM, sigterm_handler)

try:
    print "Hello"
    i = 0
    while True:
        i += 1
        print "Iteration #%i" % i
        sleep(1)
finally:
    print "Goodbye"

Now see the Ctrl+C behaviour:

$ ./signals-test.py default
Hello
Iteration #1
Iteration #2
Iteration #3
Iteration #4
^CGoodbye
Traceback (most recent call last):
  File "./signals-test.py", line 21, in <module>
    sleep(1)
KeyboardInterrupt
$ echo $?
1

This time I send it SIGTERM after 4 iterations with kill $(ps aux | grep signals-test | awk '/python/ {print $2}'):

$ ./signals-test.py default
Hello
Iteration #1
Iteration #2
Iteration #3
Iteration #4
Terminated
$ echo $?
143

This time I enable my custom SIGTERM handler and send it SIGTERM:

$ ./signals-test.py handle_signal
Hello
Iteration #1
Iteration #2
Iteration #3
Iteration #4
Goodbye
$ echo $?
0

How to run an awk commands in Windows?

Quoting is an issue if you're running awk from the command line. You'll sometimes need to use \, e.g. to quote ", but most of the time you'll use ^:

w:\srv>dir | grep ".txt" | awk "{ printf(\"echo %s@%s ^> %s.tstamp^\n\", $1, $2, $4); }"
echo 2014-09-07@22:21 > requirements-dev.txt.tstamp
echo 2014-11-28@18:14 > syncspec.txt.tstamp

How to create <input type=“text”/> dynamically

Maybe the method document.createElement(); is what you're looking for.

CodeIgniter removing index.php from url

you can go to config\config.php file and remove index.php value from this variable

$config['index_page'] = 'index.php'; // delete index.php

create .htaccess file and paste this code in it.

<IfModule mod_rewrite.c>

 Options +FollowSymLinks

 RewriteEngine On
 #Send request via index.php
 RewriteCond %{REQUEST_FILENAME} !-f
 RewriteCond %{REQUEST_FILENAME} !-d
 RewriteRule ^(.*)$ index.php/$1 [L]

</IfModule>

good chance

Is there a better way to iterate over two lists, getting one element from each list for each iteration?

Another way to do this would be to by using map.

>>> a
[1, 2, 3]
>>> b
[4, 5, 6]
>>> for i,j in map(None,a,b):
    ...   print i,j
    ...
1 4
2 5
3 6

One difference in using map compared to zip is, with zip the length of new list is
same as the length of shortest list. For example:

>>> a
[1, 2, 3, 9]
>>> b
[4, 5, 6]
>>> for i,j in zip(a,b):
    ...   print i,j
    ...
1 4
2 5
3 6

Using map on same data:

>>> for i,j in map(None,a,b):
    ...   print i,j
    ...

    1 4
    2 5
    3 6
    9 None

"static const" vs "#define" vs "enum"

If you can get away with it, static const has a lot of advantages. It obeys the normal scope principles, is visible in a debugger, and generally obeys the rules that variables obey.

However, at least in the original C standard, it isn't actually a constant. If you use #define var 5, you can write int foo[var]; as a declaration, but you can't do that (except as a compiler extension" with static const int var = 5;. This is not the case in C++, where the static const version can be used anywhere the #define version can, and I believe this is also the case with C99.

However, never name a #define constant with a lowercase name. It will override any possible use of that name until the end of the translation unit. Macro constants should be in what is effectively their own namespace, which is traditionally all capital letters, perhaps with a prefix.

Identify if a string is a number

UPDATE of Kunal Noel Answer

stringTest.All(char.IsDigit);
// This returns true if all characters of the string are digits.

But, for this case we have that empty strings will pass that test, so, you can:

if (!string.IsNullOrEmpty(stringTest) && stringTest.All(char.IsDigit)){
   // Do your logic here
}

Can VS Code run on Android?

Running VS Code on Android is not possible, at least until Android support is implemented in Electron. This has been rejected by the Electron team in the past, see electron#562

Visual Studio Codespaces and GitHub Codespaces an upcoming services that enables running VS Code in a browser. Since everything runs in a browser, it seems likely that mobile OS' will be supported.

Difference between | and || or & and && for comparison

in C (and other languages probably) a single | or & is a bitwise comparison.
The double || or && is a logical comparison.
Edit: Be sure to read Mehrdad's comment below regarding "without short-circuiting"

In practice, since true is often equivalent to 1 and false is often equivalent to 0, the bitwise comparisons can sometimes be valid and return exactly the same result.

There was once a mission critical software component I ran a static code analyzer on and it pointed out that a bitwise comparison was being used where a logical comparison should have been. Since it was written in C and due to the arrangement of logical comparisons, the software worked just fine with either. Example:

if ( (altitide > 10000) & (knots > 100) )
...

Trouble Connecting to sql server Login failed. "The login is from an untrusted domain and cannot be used with Windows authentication"

If you have two servers on the same domain (eg. APP and DB), you can also use Windows Authentication between the app and MSSQL by setting up local users on both machines that match (same username and password). If you don't have the passwords matched up, it can throw this error.

How to get every first element in 2 dimensional list

You could use this:

a = ((4.0, 4, 4.0), (3.0, 3, 3.6), (3.5, 6, 4.8))
a = np.array(a)
a[:,0]
returns >>> array([4. , 3. , 3.5])

How do I convert a factor into date format?

You were close. format= needs to be added to the as.Date call:

mydate <- factor("1/15/2006 0:00:00")
as.Date(mydate, format = "%m/%d/%Y")
## [1] "2006-01-15"

How to get numeric value from a prompt box?

parseInt() or parseFloat() are functions in JavaScript which can help you convert the values into integers or floats respectively.

Syntax:

 parseInt(string, radix);
 parseFloat(string);

string: the string expression to be parsed as a number.
radix: (optional, but highly encouraged) the base of the numeral system to be used - a number between 2 and 36.

Example:

 var x = prompt("Enter a Value", "0");
 var y = prompt("Enter a Value", "0");
 var num1 = parseInt(x);
 var num2 = parseInt(y);

After this you can perform which ever calculations you want on them.

c - warning: implicit declaration of function ‘printf’

You need to include the appropriate header

#include <stdio.h>

If you're not sure which header a standard function is defined in, the function's man page will state this.

initializing strings as null vs. empty string

There's a function empty() ready for you in std::string:

std::string a;
if(a.empty())
{
    //do stuff. You will enter this block if the string is declared like this
}

std::string a;
if(!a.empty())
{
    //You will not enter this block now
}
a = "42";
if(!a.empty())
{
    //And now you will enter this block.
}

Change an image with onclick()

How about this? It doesn't require so much coding.

_x000D_

$(".plus").click(function(){
 $(this).toggleClass("minus")  ; 
})

_x000D_

.plus{
    background-image: url("https://cdn0.iconfinder.com/data/icons/ie_Bright/128/plus_add_blue.png");
    width:130px;
    height:130px;
    background-repeat:no-repeat;
}

.plus.minus{
    background-image: url("https://cdn0.iconfinder.com/data/icons/ie_Bright/128/plus_add_minus.png");
    width:130px;
    height:130px;
    background-repeat:no-repeat;
}

_x000D_

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<a href="#"><div class="plus">CHANGE</div></a>

_x000D_

Getting Access Denied when calling the PutObject operation with bucket-level permission

Similar to one post above, (except I was using admin credentials) to get S3 uploads to work with large 50M file.

Initially my error was:

An error occurred (AccessDenied) when calling the CreateMultipartUpload operation: Access Denied

I switched the multipart_threshold to be above the 50M

aws configure set default.s3.multipart_threshold 64MB

and I got:

An error occurred (AccessDenied) when calling the PutObject operation: Access Denied

I checked bucket public access settings and all was allowed. So I found that public access can be blocked on account level for all S3 buckets:

CSS rounded corners in IE8

Internet Explorer (under version 9) does not natively support rounded corners.

There's an amazing script that will magically add it for you: CSS3 PIE.

I've used it a lot of times, with amazing results.

How to add hyperlink in JLabel?

The following code requires JHyperLink to be added to your build path.

JHyperlink stackOverflow = new JHyperlink("Click HERE!",
                "https://www.stackoverflow.com/");

JComponent[] messageComponents = new JComponent[] { stackOverflow };

JOptionPane.showMessageDialog(null, messageComponents, "StackOverflow",
                JOptionPane.PLAIN_MESSAGE);

Note that you can fill the JComponent array with more Swing components.

Result:

How do I execute a stored procedure once for each row returned by query?

You can do it with a dynamic query.

declare @cadena varchar(max) = ''
select @cadena = @cadena + 'exec spAPI ' + ltrim(id) + ';'
from sysobjects;
exec(@cadena);

SQL Server IIF vs CASE

IIF is the same as CASE WHEN <Condition> THEN <true part> ELSE <false part> END. The query plan will be the same. It is, perhaps, "syntactical sugar" as initially implemented.

CASE is portable across all SQL platforms whereas IIF is SQL SERVER 2012+ specific.

What is the difference between method overloading and overriding?

Method overriding is when a child class redefines the same method as a parent class, with the same parameters. For example, the standard Java class java.util.LinkedHashSet extends java.util.HashSet. The method add() is overridden in LinkedHashSet. If you have a variable that is of type HashSet, and you call its add() method, it will call the appropriate implementation of add(), based on whether it is a HashSet or a LinkedHashSet. This is called polymorphism.

Method overloading is defining several methods in the same class, that accept different numbers and types of parameters. In this case, the actual method called is decided at compile-time, based on the number and types of arguments. For instance, the method System.out.println() is overloaded, so that you can pass ints as well as Strings, and it will call a different version of the method.

What's the C# equivalent to the With statement in VB?

The closest thing in C# 3.0, is that you can use a constructor to initialize properties:

Stuff.Elements.Foo foo = new Stuff.Elements.Foo() {Name = "Bob Dylan", Age = 68, Location = "On Tour", IsCool = true}

What does the keyword Set actually do in VBA?

So when you want to set a value, you don't need "Set"; otherwise, if you are referring to an object, e.g. worksheet/range etc., you need using "Set".

"SDK Platform Tools component is missing!"

I have been faced with a similar problem with SDK 24.0.2, and ADT 23.0, on windows 7 and Eclipse Luna (4.4.0). The android SDK Manager comes with default Proxy IP of 127.0.0.1 (localhost) and port 8081. So as you try to run the SDK Managers as advised by earlier solutions, it will try to connect through the default proxy settings, which keep on failing(...at least on my system). Therefore, if you do not need proxy settings, simply clear default proxy settings (i.e. remove proxy server IP and Port, leaving the fields empty). Otherwise set them as necessary. To access these settings in eclipse, go Window-> Android SDK Manager->Tools->Options.

Hope this helps someone.

What does -XX:MaxPermSize do?

In Java 8 that parameter is commonly used to print a warning message like this one:

Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=512m; support was removed in 8.0

The reason why you get this message in Java 8 is because Permgen has been replaced by Metaspace to address some of PermGen's drawbacks (as you were able to see for yourself, one of those drawbacks is that it had a fixed size).

FYI: an article on Metaspace: http://java-latte.blogspot.in/2014/03/metaspace-in-java-8.html

When should I use Write-Error vs. Throw? Terminating vs. non-terminating errors

ES6 Class Multiple inheritance

An object can only have one prototype. Inheriting from two classes can be done by creating a parent object as a combination of two parent prototypes.

The syntax for subclassing makes it possible to do that in the declaration, since the right-hand side of the extends clause can be any expression. Thus, you can write a function that combines prototypes according to whatever criteria you like, and call that function in the class declaration.

How to use `subprocess` command with pipes

Or you can always use the communicate method on the subprocess objects.

cmd = "ps -A|grep 'process_name'"
ps = subprocess.Popen(cmd,shell=True,stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
output = ps.communicate()[0]
print(output)

The communicate method returns a tuple of the standard output and the standard error.

Map implementation with duplicate keys

If you want iterate about a list of key-value-pairs (as you wrote in the comment), then a List or an array should be better. First combine your keys and values:

public class Pair
{
   public Class1 key;
   public Class2 value;

   public Pair(Class1 key, Class2 value)
   {
      this.key = key;
      this.value = value;
   }

}

Replace Class1 and Class2 with the types you want to use for keys and values.

Now you can put them into an array or a list and iterate over them:

Pair[] pairs = new Pair[10];
...
for (Pair pair : pairs)
{
   ...
}

How to count items in JSON object using command line?

The shortest expression is

curl 'http://…' | jq length

Java: How to check if object is null?

if (yourObject instanceof yourClassName) will evaluate to false if yourObject is null.

'do...while' vs. 'while'

If you always want the loop to execute at least once. It's not common, but I do use it from time to time. One case where you might want to use it is trying to access a resource that could require a retry, e.g.

do
{
   try to access resource...
   put up message box with retry option

} while (user says retry);

HTML / CSS Popup div on text click

You can simply use jQuery UI Dialog

Example:

_x000D_

$(function() {_x000D_
  $("#dialog").dialog();_x000D_
});

_x000D_

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<html lang="en">_x000D_
_x000D_
<head>_x000D_
  <meta charset="utf-8" />_x000D_
  <title>jQuery UI Dialog - Default functionality</title>_x000D_
  <link rel="stylesheet" href="http://code.jquery.com/ui/1.10.3/themes/smoothness/jquery-ui.css" />_x000D_
  <script src="http://code.jquery.com/ui/1.10.3/jquery-ui.js"></script>_x000D_
  <link rel="stylesheet" href="/resources/demos/style.css" />_x000D_
</head>_x000D_
_x000D_
<body>_x000D_
  <div id="dialog" title="Basic dialog">_x000D_
    <p>This is the default dialog which is useful for displaying information. The dialog window can be moved, resized and closed with the 'x' icon.</p>_x000D_
  </div>_x000D_
</body>_x000D_
</html>

_x000D_

How do I trigger a macro to run after a new mail is received in Outlook?

Try something like this inside ThisOutlookSession:

Private Sub Application_NewMail()
    Call Your_main_macro
End Sub

My outlook vba just fired when I received an email and had that application event open.

Edit: I just tested a hello world msg box and it ran after being called in the application_newmail event when an email was received.

ORA-01438: value larger than specified precision allows for this column

This indicates you are trying to put something too big into a column. For example, you have a VARCHAR2(10) column and you are putting in 11 characters. Same thing with number.

This is happening at line 176 of package UMAIN. You would need to go and have a look at that to see what it is up to. Hopefully you can look it up in your source control (or from user_source). Later versions of Oracle report this error better, telling you which column and what value.

adding 30 minutes to datetime php/mysql

If you are using MySQL you can do it like this:

SELECT '2008-12-31 23:59:59' + INTERVAL 30 MINUTE;

For a pure PHP solution use strtotime

strtotime('+ 30 minute',$yourdate);

How to get UTC value for SYSDATE on Oracle

Usually, I work with DATE columns, not the larger but more precise TIMESTAMP used by some answers.

The following will return the current UTC date as just that -- a DATE.

CAST(sys_extract_utc(SYSTIMESTAMP) AS DATE)

I often store dates like this, usually with the field name ending in _UTC to make it clear for the developer. This allows me to avoid the complexity of time zones until last-minute conversion by the user's client. Oracle can store time zone detail with some data types, but those types require more table space than DATE, and knowledge of the original time zone is not always required.

How to test Spring Data repositories?

With JUnit5 and @DataJpaTest test will look like (kotlin code):

@DataJpaTest
@ExtendWith(value = [SpringExtension::class])
class ActivityJpaTest {

    @Autowired
    lateinit var entityManager: TestEntityManager

    @Autowired
    lateinit var myEntityRepository: MyEntityRepository

    @Test
    fun shouldSaveEntity() {
        // when
        val savedEntity = myEntityRepository.save(MyEntity(1, "test")

        // then 
        Assertions.assertNotNull(entityManager.find(MyEntity::class.java, savedEntity.id))
    }
}

You could use TestEntityManager from org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager package in order to validate entity state.

cannot import name patterns

Yes:

from django.conf.urls.defaults import ... # is for django 1.3
from django.conf.urls  import ...         # is for django 1.4

I met this problem too.

Big-oh vs big-theta

Because there are algorithms whose best-case is quick, and thus it's technically a big O, not a big Theta.

Big O is an upper bound, big Theta is an equivalence relation.

Converting Swagger specification JSON to HTML documentation

I spent a lot of time and tried a lot of different solutions - in the end I did it this way :

<html>
    <head>    
        <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/[email protected]/swagger-ui.css">
        <script src="//unpkg.com/swagger-ui-dist@3/swagger-ui-bundle.js"></script>
        <script>

            function render() {
                var ui = SwaggerUIBundle({
                    url:  `path/to/my/swagger.yaml`,
                    dom_id: '#swagger-ui',
                    presets: [
                        SwaggerUIBundle.presets.apis,
                        SwaggerUIBundle.SwaggerUIStandalonePreset
                    ]
                });
            }

        </script>
    </head>

    <body onload="render()">
        <div id="swagger-ui"></div>
    </body>
</html>

You just need to have path/to/my/swagger.yaml served from the same location.
(or use CORS headers)

Initialize value of 'var' in C# to null

var variables still have a type - and the compiler error message says this type must be established during the declaration.

The specific request (assigning an initial null value) can be done, but I don't recommend it. It doesn't provide an advantage here (as the type must still be specified) and it could be viewed as making the code less readable:

var x = (String)null;

Which is still "type inferred" and equivalent to:

String x = null;

The compiler will not accept var x = null because it doesn't associate the null with any type - not even Object. Using the above approach, var x = (Object)null would "work" although it is of questionable usefulness.

Generally, when I can't use var's type inference correctly then

I am at a place where it's best to declare the variable explicitly; or
I should rewrite the code such that a valid value (with an established type) is assigned during the declaration.

The second approach can be done by moving code into methods or functions.

convert json ipython notebook(.ipynb) to .py file

You can use the following script to convert jupyter notebook to Python script, or view the code directly.

To do this, write the following contents into a file cat_ipynb, then chmod +x cat_ipynb.

#!/usr/bin/env python
import sys
import json

for file in sys.argv[1:]:
    print('# file: %s' % file)
    print('# vi: filetype=python')
    print('')
    code = json.load(open(file))

    for cell in code['cells']:
        if cell['cell_type'] == 'code':
            print('# -------- code --------')
            for line in cell['source']:
                print(line, end='')
            print('\n')
        elif cell['cell_type'] == 'markdown':
            print('# -------- markdown --------')
            for line in cell['source']:
                print("#", line, end='')
            print('\n')

Then you can use

cat_ipynb your_notebook.ipynb > output.py

Or show it with vi directly

cat_ipynb your_notebook.ipynb | view -

How do I keep CSS floats in one line?

Another option: Do not float your right column; just give it a left margin to move it beyond the float. You'll need a hack or two to fix IE6, but that's the basic idea.

How do I calculate a trendline for a graph?

Regarding a previous answer

if (B) y = offset + slope*x

then (C) offset = y/(slope*x) is wrong

offset = y-(slope*x)

See: http://zedgraph.org/wiki/index.php?title=Trend

When tracing out variables in the console, How to create a new line?

In ES6/ES2015 you can use string literal syntax called template literals. Template strings use backtick character instead of single quote ' or double quote marks ". They also preserve new line and tab

_x000D_

const roleName = 'test1';_x000D_
const role_ID = 'test2';_x000D_
const modal_ID = 'test3';_x000D_
const related = 'test4';_x000D_
        _x000D_
console.log(`_x000D_
  roleName = ${roleName}_x000D_
  role_ID = ${role_ID}_x000D_
  modal_ID = ${modal_ID}_x000D_
  related = ${related}_x000D_
`);

_x000D_

Why do I have to define LD_LIBRARY_PATH with an export every time I run my application?

Use

export LD_LIBRARY_PATH="/path/to/library/"

in your .bashrc otherwise, it'll only be available to bash and not any programs you start.

Try -R/path/to/library/ flag when you're linking, it'll make the program look in that directory and you won't need to set any environment variables.

EDIT: Looks like -R is Solaris only, and you're on Linux.

An alternate way would be to add the path to /etc/ld.so.conf and run ldconfig. Note that this is a global change that will apply to all dynamically linked binaries.

How to select all and copy in vim?

ggVG

will select from beginning to end

Postgres - Transpose Rows to Columns

Use crosstab() from the tablefunc module.

SELECT * FROM crosstab(
   $$SELECT user_id, user_name, rn, email_address
     FROM  (
        SELECT u.user_id, u.user_name, e.email_address
             , row_number() OVER (PARTITION BY u.user_id
                            ORDER BY e.creation_date DESC NULLS LAST) AS rn
        FROM   usr u
        LEFT   JOIN email_tbl e USING (user_id)
        ) sub
     WHERE  rn < 4
     ORDER  BY user_id
   $$
  , 'VALUES (1),(2),(3)'
   ) AS t (user_id int, user_name text, email1 text, email2 text, email3 text);

I used dollar-quoting for the first parameter, which has no special meaning. It's just convenient if you have to escape single quotes in the query string which is a common case:

Insert text with single quotes in PostgreSQL

Detailed explanation and instructions here:

PostgreSQL Crosstab Query

And in particular, for "extra columns":

Pivot on Multiple Columns using Tablefunc

The special difficulties here are:

The lack of key names.
-> We substitute with row_number() in a subquery.
The varying number of emails.
-> We limit to a max. of three in the outer SELECT
and use crosstab() with two parameters, providing a list of possible keys.

Pay attention to NULLS LAST in the ORDER BY.

How can I let a user download multiple files when a button is clicked?

This was the method which worked best for me and didn't open up new tabs, but just downloaded the files/images I required:

var filesForDownload = [];
filesForDownload( { path: "/path/file1.txt", name: "file1.txt" } );
filesForDownload( { path: "/path/file2.jpg", name: "file2.jpg" } );
filesForDownload( { path: "/path/file3.png", name: "file3.png" } );
filesForDownload( { path: "/path/file4.txt", name: "file4.txt" } );

$jq('input.downloadAll').click( function( e )
{
    e.preventDefault();

    var temporaryDownloadLink = document.createElement("a");
    temporaryDownloadLink.style.display = 'none';

    document.body.appendChild( temporaryDownloadLink );

    for( var n = 0; n < filesForDownload.length; n++ )
    {
        var download = filesForDownload[n];
        temporaryDownloadLink.setAttribute( 'href', download.path );
        temporaryDownloadLink.setAttribute( 'download', download.name );

        temporaryDownloadLink.click();
    }

    document.body.removeChild( temporaryDownloadLink );
} );

How to write logs in text file when using java.util.logging.Logger

Location of log file can be control through logging.properties file. And it can be passed as JVM parameter ex : java -Djava.util.logging.config.file=/scratch/user/config/logging.properties

Details: https://docs.oracle.com/cd/E23549_01/doc.1111/e14568/handler.htm

Configuring the File handler

To send logs to a file, add FileHandler to the handlers property in the logging.properties file. This will enable file logging globally.

handlers= java.util.logging.FileHandler Configure the handler by setting the following properties:

java.util.logging.FileHandler.pattern=<home directory>/logs/oaam.log
java.util.logging.FileHandler.limit=50000
java.util.logging.FileHandler.count=1
java.util.logging.FileHandler.formatter=java.util.logging.SimpleFormatter

java.util.logging.FileHandler.pattern specifies the location and pattern of the output file. The default setting is your home directory.

java.util.logging.FileHandler.limit specifies, in bytes, the maximum amount that the logger writes to any one file.

java.util.logging.FileHandler.count specifies how many output files to cycle through.

java.util.logging.FileHandler.formatter specifies the java.util.logging formatter class that the file handler class uses to format the log messages. SimpleFormatter writes brief "human-readable" summaries of log records.

To instruct java to use this configuration file instead of $JDK_HOME/jre/lib/logging.properties:

java -Djava.util.logging.config.file=/scratch/user/config/logging.properties

How do I shut down a python simpleHTTPserver?

When you run a program as a background process (by adding an & after it), e.g.:

python -m SimpleHTTPServer 8888 &

If the terminal window is still open you can do:

jobs

To get a list of all background jobs within the running shell's process.

It could look like this:

$ jobs
[1]+  Running                 python -m SimpleHTTPServer 8888 &

To kill a job, you can either do kill %1 to kill job "[1]", or do fg %1 to put the job in the foreground (fg) and then use ctrl-c to kill it. (Simply entering fg will put the last backgrounded process in the foreground).

With respect to SimpleHTTPServer it seems kill %1 is better than fg + ctrl-c. At least it doesn't protest with the kill command.

The above has been tested in Mac OS, but as far as I can remember it works just the same in Linux.

Update: For this to work, the web server must be started directly from the command line (verbatim the first code snippet). Using a script to start it will put the process out of reach of jobs.

How to convert string to float?

double x;

char *s;

s = " -2309.12E-15";

x = atof(s);     /* x = -2309.12E-15 */

printf("x = %4.4f\n",x);

How do I reflect over the members of dynamic object?

In the case of ExpandoObject, the ExpandoObject class actually implements IDictionary<string, object> for its properties, so the solution is as trivial as casting:

IDictionary<string, object> propertyValues = (IDictionary<string, object>)s;

Note that this will not work for general dynamic objects. In these cases you will need to drop down to the DLR via IDynamicMetaObjectProvider.

Start thread with member function

Since you are using C++11, lambda-expression is a nice&clean solution.

class blub {
    void test() {}
  public:
    std::thread spawn() {
      return std::thread( [this] { this->test(); } );
    }
};

since this-> can be omitted, it could be shorten to:

std::thread( [this] { test(); } )

~~or just~~ (deprecated)

~~std::thread( [=] { test(); } )~~

Plot multiple lines (data series) each with unique color in R

More than one line can be drawn on the same chart by using the lines()function

# Create the data for the chart.
v <- c(7,12,28,3,41)
t <- c(14,7,6,19,3)

# Give the chart file a name.
png(file = "line_chart_2_lines.jpg")

# Plot the bar chart.
plot(v,type = "o",col = "red", xlab = "Month", ylab = "Rain fall", 
   main = "Rain fall chart")

lines(t, type = "o", col = "blue")

# Save the file.
dev.off()

OUTPUT

How to redirect verbose garbage collection output to a file?

From the output of java -X:

    -Xloggc:<file>    log GC status to a file with time stamps

Documented here:

-Xloggc:filename

Sets the file to which verbose GC events information should be redirected for logging. The information written to this file is similar to the output of -verbose:gc with the time elapsed since the first GC event preceding each logged event. The -Xloggc option overrides -verbose:gc if both are given with the same java command.

Example:
    -Xloggc:garbage-collection.log

So the output looks something like this:

0.590: [GC 896K->278K(5056K), 0.0096650 secs]
0.906: [GC 1174K->774K(5056K), 0.0106856 secs]
1.320: [GC 1670K->1009K(5056K), 0.0101132 secs]
1.459: [GC 1902K->1055K(5056K), 0.0030196 secs]
1.600: [GC 1951K->1161K(5056K), 0.0032375 secs]
1.686: [GC 1805K->1238K(5056K), 0.0034732 secs]
1.690: [Full GC 1238K->1238K(5056K), 0.0631661 secs]
1.874: [GC 62133K->61257K(65060K), 0.0014464 secs]

Converting HTML to Excel?

Change the content type to ms-excel in the html and browser shall open the html in the Excel as xls. If you want control over the transformation of HTML to excel use POI libraries to do so.

C# ASP.NET Single Sign-On Implementation

There are multiple options to implement SSO for a .NET application.

Check out the following tutorials online:

Basics of Single Sign on, July 2012

http://www.codeproject.com/Articles/429166/Basics-of-Single-Sign-on-SSO

GaryMcAllisterOnline: ASP.NET MVC 4, ADFS 2.0 and 3rd party STS integration (IdentityServer2), Jan 2013

http://garymcallisteronline.blogspot.com/2013/01/aspnet-mvc-4-adfs-20-and-3rd-party-sts.html

The first one uses ASP.NET Web Forms, while the second one uses ASP.NET MVC4.

If your requirements allow you to use a third-party solution, also consider OpenID. There's an open source library called DotNetOpenAuth.

For further information, read MSDN blog post Integrate OpenAuth/OpenID with your existing ASP.NET application using Universal Providers.

Hope this helps!

How to refresh or show immediately in datagridview after inserting?

Try below piece of code.

this.dataGridView1.RefreshEdit();

How can I select rows with most recent timestamp for each key value?

WITH SensorTimes As (
   SELECT sensorID, MAX(timestamp) "LastReading"
   FROM sensorTable
   GROUP BY sensorID
)
SELECT s.sensorID,s.timestamp,s.sensorField1,s.sensorField2 
FROM sensorTable s
INNER JOIN SensorTimes t on s.sensorID = t.sensorID and s.timestamp = t.LastReading

Fatal error: Please read "Security" section of the manual to find out how to run mysqld as root

you might try this if you logged in with root:

mysqld --user=root

ImportError: DLL load failed: The specified module could not be found

I had the same issue with importing matplotlib.pylab with Python 3.5.1 on Win 64. Installing the Visual C++ Redistributable für Visual Studio 2015 from this links: https://www.microsoft.com/en-us/download/details.aspx?id=48145 fixed the missing DLLs.

I find it better and easier than downloading and pasting DLLs.

Using pip behind a proxy with CNTLM

Set up invironment variable in Advanced System Settings. In Command prompt it should behave like this :

C:\Windows\system32>echo %http_proxy%

http://username:passowrd@proxy:port

C:\Windows\system32>echo %https_proxy%

http://username:password@proxy:port

Later , Simply pip install whatEver should work.

How to create Temp table with SELECT * INTO tempTable FROM CTE Query

Here's one slight alteration to the answers of a query that creates the table upon execution (i.e. you don't have to create the table first):

SELECT * INTO #Temp
FROM (
select OptionNo, OptionName from Options where OptionActive = 1
) as X

How to make a Div appear on top of everything else on the screen?

Try setting position to absolute, ie.

#yourDiv{
    position: absolute;
    z-index: 10;
};

JavaScript is in array

Assuming that you're only using the array for lookup, you can use a Set (introduced in ES6), which allows you to find an element in O(1), meaning that lookup is sublinear. With the traditional methods of .includes() and .indexOf(), you still may need to look at all 500 (ie: N) elements in your array if the item specified doesn't exist in the array (or is the last item). This can be inefficient, however, with the help of a Set, you don't need to look at all elements, and instead, instantly check if the element is within your set:

_x000D_

const blockedTile = new Set(["118", "67", "190", "43", "135", "520"]);

if(blockedTile.has("118")) {
  // 118 is in your Set
  console.log("Found 118");
}

_x000D_

If for some reason you need to convert your set back into an array, you can do so through the use of Array.from() or the spread syntax (...), however, this will iterate through the entire set's contents (which will be O(N)). Sets also don't keep duplicates, meaning that your array won't contain duplicate items.

How to change ReactJS styles dynamically?

Ok, finally found the solution.

Probably due to lack of experience with ReactJS and web development...

    var Task = React.createClass({
    render: function() {
      var percentage = this.props.children + '%';
      ....
        <div className="ui-progressbar-value ui-widget-header ui-corner-left" style={{width : percentage}}/>
      ...

I created the percentage variable outside in the render function.

Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server."

My fix for this was to remove any HTML markup that was in the Text="" property of a TextBox in my asp.net code, inside an update panel. If you have more than one update panel on a page, it will affect them all, which makes it harder to work out which panel has the issue. Chris's answer above lead me to find this, but his is a very hidden answer but I think a very relevant one so here is an answer explained.

<asp:TextBox ID="bookingTBox" runat="server" ToolTip="" Width="150px" Text="<Auto Assigned>" CssClass="textboxItalicFormat"></asp:TextBox>

The above code will give this error.

The below will not.

<asp:TextBox ID="bookingTBox" runat="server" ToolTip="" Width="150px" Text="Auto Assigned" CssClass="textboxItalicFormat"></asp:TextBox>

In the second textbox code I have removed the < and > from the Text="" property. Please try this before spending time adding lines of script code, etc.

Convert date to datetime in Python

You can use datetime.combine(date, time); for the time, you create a datetime.time object initialized to midnight.

from datetime import date
from datetime import datetime

dt = datetime.combine(date.today(), datetime.min.time())

How do I remove ï»¿ from the beginning of a file?

BOM is just a sequence of characters ($EF $BB $BF for UTF-8), so just remove them using scripts or configure the editor so it's not added.

From Removing BOM from UTF-8:

#!/usr/bin/perl
@file=<>;
$file[0] =~ s/^\xEF\xBB\xBF//;
print(@file);

I am sure it translates to PHP easily.

C#: How to access an Excel cell?

How I work to automate Office / Excel:

Record a macro, this will generate a VBA template
Edit the VBA template so it will match my needs
Convert to VB.Net (A small step for men)
Leave it in VB.Net, Much more easy as doing it using C#

Unable to compile class for JSP: The type java.util.Map$Entry cannot be resolved. It is indirectly referenced from required .class files

There are a lot of correct/same answers, but for future references:

Same stands for Tomcat 7. Be aware that updating only your used frameworks' versions (as proposed in other similar questions) isn't enough.

You also have to update Tomcat plugin's version. What worked for me, using Java 7, was upgrading to version 2.2 of tomcat7-maven-plugin (= Tomcat 7.0.47).

Print PDF directly from JavaScript

Download the Print.js from http://printjs.crabbly.com/

$http({
    url: "",
    method: "GET",
    headers: {
        "Content-type": "application/pdf"
    },
    responseType: "arraybuffer"
}).success(function (data, status, headers, config) {
    var pdfFile = new Blob([data], {
        type: "application/pdf"
    });
    var pdfUrl = URL.createObjectURL(pdfFile);
    //window.open(pdfUrl);
    printJS(pdfUrl);
    //var printwWindow = $window.open(pdfUrl);
    //printwWindow.print();
}).error(function (data, status, headers, config) {
    alert("Sorry, something went wrong")
});

How to focus on a form input text field on page load using jQuery?

Why is everybody using jQuery for something simple as this.

<body OnLoad="document.myform.mytextfield.focus();">

How to solve Permission denied (publickey) error when using Git?

Its pretty straight forward. Type the below command

ssh-keygen -t rsa -b 4096 -C "[email protected]"

Generate the SSH key. Open the file and copy the contents. Go to GitHub setting page , and click on SSH key . Click on Add new SSH key, and paste the contents here. That's it :) You shouldn't see the issue again.

LINK : fatal error LNK1104: cannot open file 'D:\...\MyProj.exe'

Just to add another solution to the list, what I've found is that Visual Studio (2012 in my case) occasionally locks files under different processes.

So, on a crash, devenv.exe might still be running and holding onto the file(s). Alternatively (as I just discovered), vstestrunner or vstestdiscovery might be holding onto the file as well.

Kill all those processes and it might fix up the issue.

How to set the initial zoom/width for a webview

I'm working with loading images for this answer and I want them to be scaled to the device's width. I find that, for older phones with versions less than API 19 (KitKat), the behavior for Brian's answer isn't quite as I like it. It puts a lot of whitespace around some images on older phones, but works on my newer one. Here is my alternative, with help from this answer: Can Android's WebView automatically resize huge images? The layout algorithm SINGLE_COLUMN is deprecated, but it works and I feel like it is appropriate for working with older webviews.

WebSettings settings = webView.getSettings();

// Image set to width of device. (Must be done differently for API < 19 (kitkat))
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
    if (!settings.getLayoutAlgorithm().equals(WebSettings.LayoutAlgorithm.SINGLE_COLUMN))
        settings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.SINGLE_COLUMN);
} else {
    if (!settings.getLoadWithOverviewMode()) settings.setLoadWithOverviewMode(true);
    if (!settings.getUseWideViewPort()) settings.setUseWideViewPort(true);
}

What is the difference between require and require-dev sections in composer.json?

According to composer's manual:

require-dev (root-only)

Lists packages required for developing this package, or running tests, etc. The dev requirements of the root package are installed by default. Both install or update support the --no-dev option that prevents dev dependencies from being installed.

So running composer install will also download the development dependencies.
The reason is actually quite simple. When contributing to a specific library you may want to run test suites or other develop tools (e.g. symfony). But if you install this library to a project, those development dependencies may not be required: not every project requires a test runner.

What is the equivalent of Java's System.out.println() in Javascript?

You can always simply add an alert() prompt anywhere in a function. Especially useful for knowing if a function was called, if a function completed or where a function fails.

alert('start of function x');
alert('end of function y');
alert('about to call function a');
alert('returned from function b');

You get the idea.

Is there an easy way to attach source in Eclipse?

Another thought for making that easier when using an automated build:

When you create a jar of one of your projects, also create a source files jar:
project.jar
project-src.jar

Instead of going into the build path options dialog to add a source reference to each jar, try the following: add one source reference through the dialog. Edit your .classpath and using the first jar entry as a template, add the source jar files to each of your other jars.

This way you can use Eclipse's navigation aids to their fullest while still using something more standalone to build your projects.

How to strip HTML tags from a string in SQL Server?

How about using XQuery with a one liner:

DECLARE @MalformedXML xml, @StrippedText varchar(max)
SET @MalformedXML = @xml.query('for $x in //. return ($x)//text()')
SET @StrippedText = CAST(@MalformedXML as varchar(max))

This loops through all elements and returns the text() only.

To avoid text between elements concatenating without spaces, use:

DECLARE @MalformedXML xml, @StrippedText varchar(max)
SET @MalformedXML = @xml.query('for $x in //. return concat((($x)//text())[1]," ")')
SET @StrippedText = CAST(@MalformedXML as varchar(max))

And to respond to "How do you use this for a column:

  SELECT CAST(html_column.query('for $x in //. return concat((($x)//text()) as varchar(max))
  FROM table

For the above code, ensure your html_column is of data type xml, if not, you need to save a casted version of the html as xml. I would do this as a separate exercise when you are loading HTML data, as SQL will throw an error if it finds malformed xml, e.g. mismatched start/end tags, invalid characters.

These are excellent for when you want to build seachh phrases, strip HTML, etc.

Just note that this returns type xml, so CAST or COVERT to text where appropriate. The xml version of this data type is useless, as it is not a well formed XML.

Angular pass callback function to child component as @Input similar to AngularJS way

An alternative to the answer SnareChops gave.

You can use .bind(this) in your template to have the same effect. It may not be as clean but it saves a couple of lines. I'm currently on angular 2.4.0

@Component({
  ...
  template: '<child [myCallback]="theCallback.bind(this)"></child>',
  directives: [ChildComponent]
})
export class ParentComponent {

  public theCallback(){
    ...
  }
}

@Component({...})
export class ChildComponent{
  //This will be bound to the ParentComponent.theCallback
  @Input()
  public myCallback: Function; 
  ...
}

There is already an object named in the database

it seems there is a problem in migration process, run add-migration command in "Package Manager Console":

Add-Migration Initial -IgnoreChanges

do some changes, and then update database from "Initial" file:

Update-Database -verbose

Edit: -IgnoreChanges is in EF6 but not in EF Core, here's a workaround: https://stackoverflow.com/a/43687656/495455

How to see which flags -march=native will activate?

If you want to find out how to set-up a non-native cross compile, I found this useful:

On the target machine,

% gcc -march=native -Q --help=target | grep march
-march=                               core-avx-i

Then use this on the build machine:

% gcc -march=core-avx-i ...

Programs & Examples On #Psake

C# Telnet Library

Spark java.lang.OutOfMemoryError: Java heap space

Sending commands and strings to Terminal.app with Applescript

How do I execute a *.dll file

Division of integers in Java

Convert datetime value into string

How do you remove an array element in a foreach loop?

How to get current screen width in CSS?

Placing border inside of div and not on its edge

Getting permission denied (public key) on gitlab

Swift: Determine iOS Screen size

How to determine whether an object has a given property in JavaScript

Rails: How can I set default values in ActiveRecord?

Converting double to string

How to compare strings in C conditional preprocessor-directives

How to call an element in a numpy array?

How to generate graphs and charts from mysql database in php

NameError: global name 'xrange' is not defined in Python 3

how much memory can be accessed by a 32 bit machine?

Goal Seek Macro with Goal as a Formula

Maintain model of scope when changing between views in AngularJS

No numeric types to aggregate - change in groupby() behaviour?

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

Bootstrap 3 modal vertical position center

jQuery selector regular expressions

How to Define Callbacks in Android?

Java method to sum any number of ints

Getting Python error "from: can't read /var/mail/Bio"

Convert dataframe column to 1 or 0 for "true"/"false" values and assign to dataframe

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

How do you use Intent.FLAG_ACTIVITY_CLEAR_TOP to clear the Activity Stack?

jQuery’s .bind() vs. .on()

Better naming in Tuple classes than "Item1", "Item2"

You can't use them in EF expression trees

You can't deconstruct them in lambdas

They won't serialize nicely

react-router getting this.props.location in child components

How to search in commit messages using command line?

How do I jump to a closing bracket in Visual Studio Code?

How to check if a file exists in the Documents directory in Swift?

Prevent content from expanding grid items

How to trigger event when a variable's value is changed?

jQuery hasClass() - check for more than one class

try/catch blocks with async/await

addEventListener vs onclick

How do I find the size of a struct?

Delete/Reset all entries in Core Data?

How to cherry-pick from a remote branch?

What exceptions should be thrown for invalid or unexpected parameters in .NET?

How to Force New Google Spreadsheets to refresh and recalculate?

C++ for each, pulling from vector elements

How to use the "required" attribute with a "radio" input field

Graph visualization library in JavaScript

What is the difference between resource and endpoint?

JOptionPane YES/No Options Confirm Dialog Box Issue

wget command to download a file and save as a different filename

Converting BitmapImage to Bitmap and vice versa

Bootstrap Collapse not Collapsing

WebAPI Multiple Put/Post parameters

How to use not contains() in xpath?

Find where python is installed (if it isn't default dir)

Convert DateTime to String PHP

How to generate a Makefile with source in sub-directories using just one makefile

How to write log base(2) in c/c++

Selenium Error - The HTTP request to the remote WebDriver timed out after 60 seconds

New features in java 7

PHP compare two arrays and get the matched values not the difference

How to reverse apply a stash?

JS strings "+" vs concat method

jQuery append() - return appended elements

Intent from Fragment to Activity

Horizontal Scroll Table in Bootstrap/CSS

Removing array item by value

How to find EOF through fscanf?

Global constants file in Swift

How do I get a reference to the app delegate in Swift?

Paging with Oracle

What exactly does Double mean in java?

Deciding between double versus float

Deciding between `double` versus `float`

Deciding between `Double` versus `Float`