Programs & Examples On #Self documenting

C++ "Access violation reading location" Error

You haven't posted the findvertex method, but Access Reading Violation with an offset like 0x00000048 means that the Vertex* f; in your getCost function is receiving null, and when trying to access the member adj in the null Vertex pointer (that is, in f), it is offsetting to adj (in this case, 72 bytes ( 0x48 bytes in decimal )), it's reading near the 0 or null memory address.

Doing a read like this violates Operating-System protected memory, and more importantly means whatever you're pointing at isn't a valid pointer. Make sure findvertex isn't returning null, or do a comparisong for null on f before using it to keep yourself sane (or use an assert):

assert( f != null ); // A good sanity check

EDIT:

If you have a map for doing something like a find, you can just use the map's find method to make sure the vertex exists:

Vertex* Graph::findvertex(string s)
{
    vmap::iterator itr = map1.find( s );
    if ( itr == map1.end() )
    {
        return NULL;
    }
    return itr->second;
}

Just make sure you're still careful to handle the error case where it does return NULL. Otherwise, you'll keep getting this access violation.

Regex to match any character including new lines

Add the s modifier to your regex to cause . to match newlines:

$string =~ /(START)(.+?)(END)/s;

What is %timeit in python?

This is known as a line magic in iPython. They are unique in that their arguments only extend to the end of the current line, and magics themselves are really structured for command line development. timeit is used to time the execution of code.

If you wanted to see all of the magics you can use, you could simply type:

%lsmagic

to get a list of both line magics and cell magics.

Some further magic information from documentation here:

IPython has a system of commands we call magics that provide effectively a mini command language that is orthogonal to the syntax of Python and is extensible by the user with new commands. Magics are meant to be typed interactively, so they use command-line conventions, such as using whitespace for separating arguments, dashes for options and other conventions typical of a command-line environment.

Depending on whether you are in line or cell mode, there are two different ways to use %timeit. Your question illustrates the first way:

In [1]: %timeit range(100)

vs.

In [1]: %%timeit 
      : x = range(100)
      :

Javascript: How to loop through ALL DOM elements on a page?

Here is another example on how you can loop through a document or an element:

function getNodeList(elem){
var l=new Array(elem),c=1,ret=new Array();
//This first loop will loop until the count var is stable//
for(var r=0;r<c;r++){
    //This loop will loop thru the child element list//
    for(var z=0;z<l[r].childNodes.length;z++){

         //Push the element to the return array.
        ret.push(l[r].childNodes[z]);

        if(l[r].childNodes[z].childNodes[0]){
            l.push(l[r].childNodes[z]);c++;
        }//IF           
    }//FOR
}//FOR
return ret;
}

What is the difference between Promises and Observables?

I see a lot of people using the argument that Observable are "cancellable" but it is rather trivial to make Promise "cancellable"

_x000D_
_x000D_
function cancellablePromise(body) {_x000D_
  let resolve, reject;_x000D_
  const promise = new Promise((res, rej) => {_x000D_
    resolve = res; reject = rej;_x000D_
    body(resolve, reject)_x000D_
  })_x000D_
  promise.resolve = resolve;_x000D_
  promise.reject = reject;_x000D_
  return promise_x000D_
}_x000D_
_x000D_
// Example 1: Reject a promise prematurely_x000D_
const p1 = cancellablePromise((resolve, reject) => {_x000D_
  setTimeout(() => resolve('10', 100))_x000D_
})_x000D_
_x000D_
p1.then(value => alert(value)).catch(err => console.error(err))_x000D_
p1.reject(new Error('denied')) // expect an error in the console_x000D_
_x000D_
// Example: Resolve a promise prematurely_x000D_
const p2 = cancellablePromise((resolve, reject) => {_x000D_
  setTimeout(() => resolve('blop'), 100)_x000D_
})_x000D_
_x000D_
p2.then(value => alert(value)).catch(err => console.error(err))_x000D_
p2.resolve(200) // expect an alert with 200
_x000D_
_x000D_
_x000D_

Showing the same file in both columns of a Sublime Text window

Kinda little late but I tried to extend @Tobia's answer to set the layout "horizontal" or "vertical" driven by the command argument e.g.

{"keys": ["f6"], "command": "split_pane", "args": {"split_type": "vertical"} } 

Plugin code:

import sublime_plugin


class SplitPaneCommand(sublime_plugin.WindowCommand):
    def run(self, split_type):
        w = self.window
        if w.num_groups() == 1:
            if (split_type == "horizontal"):
                w.run_command('set_layout', {
                    'cols': [0.0, 1.0],
                    'rows': [0.0, 0.33, 1.0],
                    'cells': [[0, 0, 1, 1], [0, 1, 1, 2]]
                })
            elif (split_type == "vertical"):
                w.run_command('set_layout', {
                    "cols": [0.0, 0.46, 1.0],
                    "rows": [0.0, 1.0],
                    "cells": [[0, 0, 1, 1], [1, 0, 2, 1]]
                })

            w.focus_group(0)
            w.run_command('clone_file')
            w.run_command('move_to_group', {'group': 1})
            w.focus_group(1)
        else:
            w.focus_group(1)
            w.run_command('close')
            w.run_command('set_layout', {
                'cols': [0.0, 1.0],
                'rows': [0.0, 1.0],
                'cells': [[0, 0, 1, 1]]
            })

Locking a file in Python

Alright, so I ended up going with the code I wrote here, on my website link is dead, view on archive.org (also available on GitHub). I can use it in the following fashion:

from filelock import FileLock

with FileLock("myfile.txt.lock"):
    print("Lock acquired.")
    with open("myfile.txt"):
        # work with the file as it is now locked

How to clear the cache in NetBeans

I'll just add that I have tried to resolve reference problems caused by a missing library in the cache, and deleting the cache was not enough to solve the problem.

I closed NetBeans (7.2.1), deleted the cache, then reopened NetBeans, and it regenerated the cache, but the library was still missing (checked by looking in .../Cache/7.2.1/index/archives.properties).

To resolve the problem I had to close my open projects before closing NetBeans and deleting the cache.

Get item in the list in Scala?

Safer is to use lift so you can extract the value if it exists and fail gracefully if it does not.

data.lift(2)

This will return None if the list isn't long enough to provide that element, and Some(value) if it is.

scala> val l = List("a", "b", "c")
scala> l.lift(1)
Some("b")
scala> l.lift(5)
None

Whenever you're performing an operation that may fail in this way it's great to use an Option and get the type system to help make sure you are handling the case where the element doesn't exist.

Explanation:

This works because List's apply (which sugars to just parentheses, e.g. l(index)) is like a partial function that is defined wherever the list has an element. The List.lift method turns the partial apply function (a function that is only defined for some inputs) into a normal function (defined for any input) by basically wrapping the result in an Option.

Tomcat 7 "SEVERE: A child container failed during start"

This same issue occurred for me and stack trace

SEVERE: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[/XXXXSearch]]
    at java.util.concurrent.FutureTask.report(FutureTask.java:122)
    at java.util.concurrent.FutureTask.get(FutureTask.java:192)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:800)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[/XXXXSearch]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
    ... 6 more
Caused by: java.lang.IllegalStateException: Unable to complete the scan for annotations for web application [/XXXXSearch]. Possible root causes include a too low setting for -Xss and illegal cyclic inheritance dependencies
    at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:2109)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsJar(ContextConfig.java:1981)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsUrl(ContextConfig.java:1947)
    at org.apache.catalina.startup.ContextConfig.processAnnotations(ContextConfig.java:1932)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1326)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:878)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:369)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5179)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 6 more
Caused by: java.lang.StackOverflowError
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269)

In my analysis what i found was, this issue is occurred when illegal cyclic inheritance dependencies caused for Tomcat startup annotation processing.

But my project had lot of dependency JARs, and couldn't found which one is responsible for this.

After trying so many unhappy approaches What i did was , I have updated my tomcat plugin to following and ran the same scenario,

<plugin>
    <groupId>org.apache.tomcat.maven</groupId>
    <artifactId>tomcat8-maven-plugin</artifactId>
    <version>3.0-r1756463</version>
<\plugin>

Then i was able to find which JAR is caused to this issue ,

Aug 23, 2017 2:32:12 PM org.apache.catalina.startup.ContextConfig processAnnotationsJar
SEVERE: Unable to process Jar entry [cryptix/test/TestLOKI91.class] from Jar [jar:file:/C:/Users/Tharinda/.m2/repository/cryptix/cryptix/1.2.2/cryptix-1.2.2.jar!/] for annotations
java.io.EOFException
    at org.apache.tomcat.util.bcel.classfile.FastDataInputStream.readUnsignedShort(FastDataInputStream.java:120)
    at org.apache.tomcat.util.bcel.classfile.ClassParser.readAttributes(ClassParser.java:110)
    at org.apache.tomcat.util.bcel.classfile.ClassParser.parse(ClassParser.java:94)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:1994)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsJar(ContextConfig.java:1944)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsUrl(ContextConfig.java:1919)
    at org.apache.catalina.startup.ContextConfig.processAnnotations(ContextConfig.java:1880)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1149)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:771)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:305)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

Then just solving the issue with cryptix-1.2.2.jar solved this problem.

I strongly recommend to move tomcat8-maven-plugin which seems stable and less buggy at the moment.

what is numeric(18, 0) in sql server 2008 r2

This page explains it pretty well.

As a numeric the allowable range that can be stored in that field is -10^38 +1 to 10^38 - 1.

The first number in parentheses is the total number of digits that will be stored. Counting both sides of the decimal. In this case 18. So you could have a number with 18 digits before the decimal 18 digits after the decimal or some combination in between.

The second number in parentheses is the total number of digits to be stored after the decimal. Since in this case the number is 0 that basically means only integers can be stored in this field.

So the range that can be stored in this particular field is -(10^18 - 1) to (10^18 - 1)

Or -999999999999999999 to 999999999999999999 Integers only

Calculating Covariance with Python and Numpy

When a and b are 1-dimensional sequences, numpy.cov(a,b)[0][1] is equivalent to your cov(a,b).

The 2x2 array returned by np.cov(a,b) has elements equal to

cov(a,a)  cov(a,b)

cov(a,b)  cov(b,b)

(where, again, cov is the function you defined above.)

php multidimensional array get values

For people who searched for php multidimensional array get values and actually want to solve problem comes from getting one column value from a 2 dimensinal array (like me!), here's a much elegant way than using foreach, which is array_column

For example, if I only want to get hotel_name from the below array, and form to another array:

$hotels = [
    [
        'hotel_name' => 'Hotel A',
        'info' => 'Hotel A Info',
    ],
    [
        'hotel_name' => 'Hotel B',
        'info' => 'Hotel B Info',
    ]
];

I can do this using array_column:

$hotel_name = array_column($hotels, 'hotel_name');

print_r($hotel_name); // Which will give me ['Hotel A', 'Hotel B']

For the actual answer for this question, it can also be beautified by array_column and call_user_func_array('array_merge', $twoDimensionalArray);

Let's make the data in PHP:

$hotels = [
    [
        'hotel_name' => 'Hotel A',
        'info' => 'Hotel A Info',
        'rooms' => [
            [
                'room_name' => 'Luxury Room',
                'bed' => 2,
                'boards' => [
                    'board_id' => 1,
                    'price' => 200
                ]
            ],
            [
                'room_name' => 'Non Luxy Room',
                'bed' => 4,
                'boards' => [
                    'board_id' => 2,
                    'price' => 150
                ]
            ],
        ]
    ],
    [
        'hotel_name' => 'Hotel B',
        'info' => 'Hotel B Info',
        'rooms' => [
            [
                'room_name' => 'Luxury Room',
                'bed' => 2,
                'boards' => [
                    'board_id' => 3,
                    'price' => 900
                ]
            ],
            [
                'room_name' => 'Non Luxy Room',
                'bed' => 4,
                'boards' => [
                    'board_id' => 4,
                    'price' => 300
                ]
            ],
        ]
    ]
];

And here's the calculation:

$rooms = array_column($hotels, 'rooms');
$rooms = call_user_func_array('array_merge', $rooms);
$boards = array_column($rooms, 'boards');

foreach($boards as $board){
    $board_id = $board['board_id'];
    $price = $board['price'];
    echo "Board ID is: ".$board_id." and price is: ".$price . "<br/>";
}

Which will give you the following result:

Board ID is: 1 and price is: 200
Board ID is: 2 and price is: 150
Board ID is: 3 and price is: 900
Board ID is: 4 and price is: 300

concat scope variables into string in angular directive expression

You can just concat the values using +

<a ng-click="$navigate.go('#/path/' + obj.val1 + '/' + obj.val2)">{{obj.val1}}, {{obj.val2}}</a>

Simple example on jsfiddle

I am sure the code you posted is a simplified example, if your path building is more complex I would recommend extracting out a function (or service) that would build your urls so you can effectively write unit test.

Razor view engine - How can I add Partial Views

You partial looks much like an editor template so you could include it as such (assuming of course that your partial is placed in the ~/views/controllername/EditorTemplates subfolder):

@Html.EditorFor(model => model.SomePropertyOfTypeLocaleBaseModel)

Or if this is not the case simply:

@Html.Partial("nameOfPartial", Model)

Proper use of the IDisposable interface

First of definition. For me unmanaged resource means some class, which implements IDisposable interface or something created with usage of calls to dll. GC doesn't know how to deal with such objects. If class has for example only value types, then I don't consider this class as class with unmanaged resources. For my code I follow next practices:

  1. If created by me class uses some unmanaged resources then it means that I should also implement IDisposable interface in order to clean memory.
  2. Clean objects as soon as I finished usage of it.
  3. In my dispose method I iterate over all IDisposable members of class and call Dispose.
  4. In my Dispose method call GC.SuppressFinalize(this) in order to notify garbage collector that my object was already cleaned up. I do it because calling of GC is expensive operation.
  5. As additional precaution I try to make possible calling of Dispose() multiple times.
  6. Sometime I add private member _disposed and check in method calls did object was cleaned up. And if it was cleaned up then generate ObjectDisposedException
    Following template demonstrates what I described in words as sample of code:

public class SomeClass : IDisposable
    {
        /// <summary>
        /// As usually I don't care was object disposed or not
        /// </summary>
        public void SomeMethod()
        {
            if (_disposed)
                throw new ObjectDisposedException("SomeClass instance been disposed");
        }

        public void Dispose()
        {
            Dispose(true);
        }

        private bool _disposed;

        protected virtual void Dispose(bool disposing)
        {
            if (_disposed)
                return;
            if (disposing)//we are in the first call
            {
            }
            _disposed = true;
        }
    }

How to have stored properties in Swift, the same way I had on Objective-C?

I prefer doing code in pure Swift and not rely on Objective-C heritage. Because of this I wrote pure Swift solution with two advantages and two disadvantages.

Advantages:

  1. Pure Swift code

  2. Works on classes and completions or more specifically on Any object

Disadvantages:

  1. Code should call method willDeinit() to release objects linked to specific class instance to avoid memory leaks

  2. You cannot make extension directly to UIView for this exact example because var frame is extension to UIView, not part of class.

EDIT:

import UIKit

var extensionPropertyStorage: [NSObject: [String: Any]] = [:]

var didSetFrame_ = "didSetFrame"

extension UILabel {

    override public var frame: CGRect {

        get {
            return didSetFrame ?? CGRectNull
        }

        set {
            didSetFrame = newValue
        }
    }

    var didSetFrame: CGRect? {

        get {
            return extensionPropertyStorage[self]?[didSetFrame_] as? CGRect
        }

        set {
            var selfDictionary = extensionPropertyStorage[self] ?? [String: Any]()

            selfDictionary[didSetFrame_] = newValue

            extensionPropertyStorage[self] = selfDictionary
        }
    }

    func willDeinit() {
        extensionPropertyStorage[self] = nil
    }
}

Exit while loop by user hitting ENTER key

if repr(User) == repr(''):
    break

"This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded"

I got this error too, but my problem was that I was using an older version of GACUTIL.EXE.

Once I had the correct GACUTIL for the latest .NET version installed, it worked fine.

The error is misleading because it makes it look like it's the DLL you're trying to register that incorrect.

DropDownList's SelectedIndexChanged event not firing

Instead of what you have written, you can write it directly in the SelectedIndexChanged event of the dropdownlist control, e.g.

protected void ddlleavetype_SelectedIndexChanged(object sender, EventArgs e)
{
 //code goes here
}

Convert a python dict to a string and back

Convert dictionary into JSON (string)

import json 

mydict = { "name" : "Don", 
          "surname" : "Mandol", 
          "age" : 43} 

result = json.dumps(mydict)

print(result[0:20])

will get you:

{"name": "Don", "sur

Convert string into dictionary

back_to_mydict = json.loads(result) 

is there a tool to create SVG paths from an SVG file?

Open the SVG with you text editor. If you have some luck the file will contain something like:

<path d="M52.52,26.064c-1.612,0-3.149,0.336-4.544,0.939L43.179,15.89c-0.122-0.283-0.337-0.484-0.58-0.637  c-0.212-0.147-0.459-0.252-0.738-0.252h-8.897c-0.743,0-1.347,0.603-1.347,1.347c0,0.742,0.604,1.345,1.347,1.345h6.823  c0.331,0.018,1.022,0.139,1.319,0.825l0.54,1.247l0,0L41.747,20c0.099,0.291,0.139,0.749-0.604,0.749H22.428  c-0.857,0-1.262-0.451-1.434-0.732l-0.11-0.221v-0.003l-0.552-1.092c0,0,0,0,0-0.001l-0.006-0.011l-0.101-0.2l-0.012-0.002  l-0.225-0.405c-0.049-0.128-0.031-0.337,0.65-0.337h2.601c0,0,1.528,0.127,1.57-1.274c0.021-0.722-0.487-1.464-1.166-1.464  c-0.68,0-9.149,0-9.149,0s-1.464-0.17-1.549,1.369c0,0.688,0.571,1.369,1.379,1.369c0.295,0,0.7-0.003,1.091-0.007  c0.512,0.014,1.389,0.121,1.677,0.679l0,0l0.117,0.219c0.287,0.564,0.751,1.473,1.313,2.574c0.04,0.078,0.083,0.166,0.126,0.246  c0.107,0.285,0.188,0.807-0.208,1.483l-2.403,4.082c-1.397-0.606-2.937-0.947-4.559-0.947c-6.329,0-11.463,5.131-11.463,11.462  S5.15,48.999,11.479,48.999c5.565,0,10.201-3.968,11.243-9.227l5.767,0.478c0.235,0.02,0.453-0.04,0.654-0.127  c0.254-0.043,0.507-0.128,0.713-0.311l13.976-12.276c0.192-0.164,0.874-0.679,1.151-0.039l0.446,1.035  c-2.659,2.099-4.372,5.343-4.372,8.995c0,6.329,5.131,11.461,11.462,11.461c6.329,0,11.464-5.132,11.464-11.461  C63.983,31.196,58.849,26.064,52.52,26.064z M11.479,46.756c-4.893,0-8.861-3.968-8.861-8.861s3.969-8.859,8.861-8.859  c1.073,0,2.098,0.201,3.051,0.551l-4.178,7.098c-0.119,0.202-0.167,0.418-0.183,0.633c-0.003,0.022-0.015,0.036-0.016,0.054  c-0.007,0.091,0.02,0.172,0.03,0.258c0.008,0.054,0.004,0.105,0.018,0.158c0.132,0.559,0.592,1,1.193,1.05l8.782,0.727  C19.397,43.655,15.802,46.756,11.479,46.756z M15.169,36.423c-0.003-0.002-0.003-0.002-0.006-0.002  c-1.326-0.109-0.482-1.621-0.436-1.704l2.224-3.78c1.801,1.418,3.037,3.515,3.32,5.908L15.169,36.423z M25.607,37.285l-2.688-0.223  c-0.144-3.521-1.87-6.626-4.493-8.629l1.085-1.842c0.938-1.593,1.756,0.001,1.756,0.001l0,0c1.772,3.48,3.65,7.169,4.745,9.331  C26.012,35.924,26.746,37.379,25.607,37.285z M43.249,24.273L30.78,35.225c0,0.002,0,0.002,0,0.002  c-1.464,1.285-2.177-0.104-2.188-0.127l-5.297-10.517l0,0c-0.471-0.936,0.41-1.062,0.805-1.073h17.926c0,0,1.232-0.012,1.354,0.267  v0.002C43.458,23.961,43.473,24.077,43.249,24.273z M52.52,46.745c-4.891,0-8.86-3.968-8.86-8.858c0-2.625,1.146-4.976,2.962-6.599  l2.232,5.174c0.421,0.977,0.871,1.061,0.978,1.065h0.023h1.674c0.9,0,0.592-0.913,0.473-1.199l-2.862-6.631  c1.043-0.43,2.184-0.672,3.381-0.672c4.891,0,8.861,3.967,8.861,8.861C61.381,42.777,57.41,46.745,52.52,46.745z" fill="#241F20"/>

The d attribute is what you are looking for.

How to terminate a Python script

While you should generally prefer sys.exit because it is more "friendly" to other code, all it actually does is raise an exception.

If you are sure that you need to exit a process immediately, and you might be inside of some exception handler which would catch SystemExit, there is another function - os._exit - which terminates immediately at the C level and does not perform any of the normal tear-down of the interpreter; for example, hooks registered with the "atexit" module are not executed.

How to "grep" for a filename instead of the contents of a file?

The easiest way is

find . | grep test

here find will list all the files in the (.) ie current directory, recursively. And then it is just a simple grep. all the files which name has "test" will appeared.

you can play with grep as per your requirement. Note : As the grep is generic string classification, It can result in giving you not only file names. but if a path has a directory ('/xyz_test_123/other.txt') would also comes to the result set. cheers

How to get the currently logged in user's user id in Django?

I wrote this in an ajax view, but it is a more expansive answer giving the list of currently logged in and logged out users.

The is_authenticated attribute always returns True for my users, which I suppose is expected since it only checks for AnonymousUsers, but that proves useless if you were to say develop a chat app where you need logged in users displayed.

This checks for expired sessions and then figures out which user they belong to based on the decoded _auth_user_id attribute:

def ajax_find_logged_in_users(request, client_url):
    """
    Figure out which users are authenticated in the system or not.
    Is a logical way to check if a user has an expired session (i.e. they are not logged in)
    :param request:
    :param client_url:
    :return:
    """
    # query non-expired sessions
    sessions = Session.objects.filter(expire_date__gte=timezone.now())
    user_id_list = []
    # build list of user ids from query
    for session in sessions:
        data = session.get_decoded()
        # if the user is authenticated
        if data.get('_auth_user_id'):
            user_id_list.append(data.get('_auth_user_id'))

    # gather the logged in people from the list of pks
    logged_in_users = CustomUser.objects.filter(id__in=user_id_list)
    list_of_logged_in_users = [{user.id: user.get_name()} for user in logged_in_users]

    # Query all logged in staff users based on id list
    all_staff_users = CustomUser.objects.filter(is_resident=False, is_active=True, is_superuser=False)
    logged_out_users = list()
    # for some reason exclude() would not work correctly, so I did this the long way.
    for user in all_staff_users:
        if user not in logged_in_users:
            logged_out_users.append(user)
    list_of_logged_out_users = [{user.id: user.get_name()} for user in logged_out_users]

    # return the ajax response
    data = {
        'logged_in_users': list_of_logged_in_users,
        'logged_out_users': list_of_logged_out_users,
    }
    print(data)

    return HttpResponse(json.dumps(data))

How can I access the MySQL command line with XAMPP for Windows?

I had the same issue. Fistly, thats what i have :

  1. win 10
  2. xampp
  3. git bash

and i have done this to fix my problem :

  1. go to search box(PC)
  2. tape this environnement variable
  3. go to 'path' click 'edit'
  4. add this "%systemDrive%\xampp\mysql\bin\" C:\xampp\mysql\bin\
  5. click ok
  6. go to Git Bash and right click it and open it and run as administrator
  7. right this on your Git Bash winpty mysql -u root if your password is empty or winpty mysql -u root -p if you do have a password

how to change text in Android TextView

:) Your using the thread in a wrong way. Just do the following:

private void runthread()
{

splashTread = new Thread() {
            @Override
            public void run() {
                try {
                    synchronized(this){

                        //wait 5 sec
                        wait(_splashTime);
                    }

                } catch(InterruptedException e) {}
                finally {
                    //call the handler to set the text
                }
            }
        };

        splashTread.start(); 
}

That's it.

Twig ternary operator, Shorthand if-then-else

You can use shorthand syntax as of Twig 1.12.0

{{ foo ?: 'no' }} is the same as {{ foo ? foo : 'no' }}
{{ foo ? 'yes' }} is the same as {{ foo ? 'yes' : '' }}

Remove URL parameters without refreshing page

None of these solutions really worked for me, here is a IE11-compatible function that can also remove multiple parameters:

/**
* Removes URL parameters
* @param removeParams - param array
*/
function removeURLParameters(removeParams) {
  const deleteRegex = new RegExp(removeParams.join('=|') + '=')

  const params = location.search.slice(1).split('&')
  let search = []
  for (let i = 0; i < params.length; i++) if (deleteRegex.test(params[i]) === false) search.push(params[i])

  window.history.replaceState({}, document.title, location.pathname + (search.length ? '?' + search.join('&') : '') + location.hash)
}

removeURLParameters(['param1', 'param2'])

How do I do a HTTP GET in Java?

If you dont want to use external libraries, you can use URL and URLConnection classes from standard Java API.

An example looks like this:

String urlString = "http://wherever.com/someAction?param1=value1&param2=value2....";
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
InputStream is = conn.getInputStream();
// Do what you want with that stream

Can I stop 100% Width Text Boxes from extending beyond their containers?

Actually, it's because CSS defines 100% relative to the entire width of the container, including its margins, borders, and padding; that means that the space avail. to its contents is some amount smaller than 100%, unless the container has no margins, borders, or padding.

This is counter-intuitive and widely regarded by many to be a mistake that we are now stuck with. It effectively means that % dimensions are no good for anything other than a top level container, and even then, only if it has no margins, borders or padding.

Note that the text field's margins, borders, and padding are included in the CSS size specified for it - it's the container's which throw things off.

I have tolerably worked around it by using 98%, but that is a less than perfect solution, since the input fields tend to fall further short as the container gets larger.


EDIT: I came across this similar question - I've never tried the answer given, and I don't know for sure if it applies to your problem, but it seems like it will.

How to convert a .eps file to a high quality 1024x1024 .jpg?

For vector graphics, ImageMagick has both a render resolution and an output size that are independent of each other.

Try something like

convert -density 300 image.eps -resize 1024x1024 image.jpg

Which will render your eps at 300dpi. If 300 * width > 1024, then it will be sharp. If you render it too high though, you waste a lot of memory drawing a really high-res graphic only to down sample it again. I don't currently know of a good way to render it at the "right" resolution in one IM command.

The order of the arguments matters! The -density X argument needs to go before image.eps because you want to affect the resolution that the input file is rendered at.

This is not super obvious in the manpage for convert, but is hinted at:

SYNOPSIS

convert [input-option] input-file [output-option] output-file

How to convert std::string to lower case?

Boost provides a string algorithm for this:

#include <boost/algorithm/string.hpp>

std::string str = "HELLO, WORLD!";
boost::algorithm::to_lower(str); // modifies str

Or, for non-in-place:

#include <boost/algorithm/string.hpp>

const std::string str = "HELLO, WORLD!";
const std::string lower_str = boost::algorithm::to_lower_copy(str);

Inheriting from a template class in c++

#include<iostream>

using namespace std;

template<class t> 
class base {
protected:
    t a;
public:
    base(t aa){
        a = aa;
        cout<<"base "<<a<<endl;
    }
};

template <class t> 
class derived: public base<t>{
    public:
        derived(t a): base<t>(a) {
        }
        //Here is the method in derived class 
    void sampleMethod() {
        cout<<"In sample Method"<<endl;
    }
};

int main() {
    derived<int> q(1);
    // calling the methods
    q.sampleMethod();
}

Match whitespace but not newlines

What you are looking for is the POSIX blank character class. In Perl it is referenced as:

[[:blank:]]

in Java (don't forget to enable UNICODE_CHARACTER_CLASS):

\p{Blank}

Compared to the similar \h, POSIX blank is supported by a few more regex engines (reference). A major benefit is that its definition is fixed in Annex C: Compatibility Properties of Unicode Regular Expressions and standard across all regex flavors that support Unicode. (In Perl, for example, \h chooses to additionally include the MONGOLIAN VOWEL SEPARATOR.) However, an argument in favor of \h is that it always detects Unicode characters (even if the engines don't agree on which), while POSIX character classes are often by default ASCII-only (as in Java).

But the problem is that even sticking to Unicode doesn't solve the issue 100%. Consider the following characters which are not considered whitespace in Unicode:

The aforementioned Mongolian vowel separator isn't included for what is probably a good reason. It, along with 200C and 200D, occur within words (AFAIK), and therefore breaks the cardinal rule that all other whitespace obeys: you can tokenize with it. They're more like modifiers. However, ZERO WIDTH SPACE, WORD JOINER, and ZERO WIDTH NON-BREAKING SPACE (if it used as other than a byte-order mark) fit the whitespace rule in my book. Therefore, I include them in my horizontal whitespace character class.

In Java:

static public final String HORIZONTAL_WHITESPACE = "[\\p{Blank}\\u200B\\u2060\\uFFEF]"

Sort hash by key, return hash in Ruby

No, it is not (Ruby 1.9.x)

require 'benchmark'

h = {"a"=>1, "c"=>3, "b"=>2, "d"=>4}
many = 100_000

Benchmark.bm do |b|
  GC.start

  b.report("hash sort") do
    many.times do
      Hash[h.sort]
    end
  end

  GC.start

  b.report("keys sort") do
    many.times do
      nh = {}
      h.keys.sort.each do |k|
        nh[k] = h[k]
      end
    end
  end
end

       user     system      total        real
hash sort  0.400000   0.000000   0.400000 (  0.405588)
keys sort  0.250000   0.010000   0.260000 (  0.260303)

For big hashes difference will grow up to 10x and more

Get a list of URLs from a site

So, in an ideal world you'd have a spec for all pages in your site. You would also have a test infrastructure that could hit all your pages to test them.

You're presumably not in an ideal world. Why not do this...?

  1. Create a mapping between the well known old URLs and the new ones. Redirect when you see an old URL. I'd possibly consider presenting a "this page has moved, it's new url is XXX, you'll be redirected shortly".

  2. If you have no mapping, present a "sorry - this page has moved. Here's a link to the home page" message and redirect them if you like.

  3. Log all redirects - especially the ones with no mapping. Over time, add mappings for pages that are important.

PowerShell script to return members of multiple security groups

This is cleaner and will put in a csv.

Import-Module ActiveDirectory

$Groups = (Get-AdGroup -filter * | Where {$_.name -like "**"} | select name -expandproperty name)


$Table = @()

$Record = [ordered]@{
"Group Name" = ""
"Name" = ""
"Username" = ""
}



Foreach ($Group in $Groups)
{

$Arrayofmembers = Get-ADGroupMember -identity $Group | select name,samaccountname

foreach ($Member in $Arrayofmembers)
{
$Record."Group Name" = $Group
$Record."Name" = $Member.name
$Record."UserName" = $Member.samaccountname
$objRecord = New-Object PSObject -property $Record
$Table += $objrecord

}

}

$Table | export-csv "C:\temp\SecurityGroups.csv" -NoTypeInformation

How to use 'git pull' from the command line?

Open up your git bash and type

echo $HOME

This shall be the same folder as you get when you open your command window (cmd) and type

echo %USERPROFILE%

And – of course – the .ssh folder shall be present on THAT directory.

How to remove leading zeros using C#

This is the code you need:

string strInput = "0001234";
strInput = strInput.TrimStart('0');

How to connect Bitbucket to Jenkins properly

I had a similar problems, till I got it working. Below is the full listing of the integration:

  1. Generate public/private keys pair: ssh-keygen -t rsa
  2. Copy the public key (~/.ssh/id_rsa.pub) and paste it in Bitbucket SSH keys, in user’s account management console: enter image description here

  3. Copy the private key (~/.ssh/id_rsa) to new user (or even existing one) with private key credentials, in this case, username will not make a difference, so username can be anything: enter image description here

  4. run this command to test if you can get access to Bitbucket account: ssh -T [email protected]

  5. OPTIONAL: Now, you can use your git to to copy repo to your desk without passwjord git clone [email protected]:username/repo_name.git
  6. Now you can enable Bitbucket hooks for Jenkins push notifications and automatic builds, you will do that in 2 steps:

    1. Add an authentication token inside the job/project you configure, it can be anything: enter image description here

    2. In Bitbucket hooks: choose jenkins hooks, and fill the fields as below: enter image description here

Where:

**End point**: username:usertoken@jenkins_domain_or_ip
**Project name**: is the name of job you created on Jenkins
**Token**: Is the authorization token you added in the above steps in your Jenkins' job/project 

Recommendation: I usually add the usertoken as the authorization Token (in both Jenkins Auth Token job configuration and Bitbucket hooks), making them one variable to ease things on myself.

Converting an object to a string

If you only care about strings, objects, and arrays:

function objectToString (obj) {
        var str = '';
        var i=0;
        for (var key in obj) {
            if (obj.hasOwnProperty(key)) {
                if(typeof obj[key] == 'object')
                {
                    if(obj[key] instanceof Array)
                    {
                        str+= key + ' : [ ';
                        for(var j=0;j<obj[key].length;j++)
                        {
                            if(typeof obj[key][j]=='object') {
                                str += '{' + objectToString(obj[key][j]) + (j > 0 ? ',' : '') + '}';
                            }
                            else
                            {
                                str += '\'' + obj[key][j] + '\'' + (j > 0 ? ',' : ''); //non objects would be represented as strings
                            }
                        }
                        str+= ']' + (i > 0 ? ',' : '')
                    }
                    else
                    {
                        str += key + ' : { ' + objectToString(obj[key]) + '} ' + (i > 0 ? ',' : '');
                    }
                }
                else {
                    str +=key + ':\'' + obj[key] + '\'' + (i > 0 ? ',' : '');
                }
                i++;
            }
        }
        return str;
    }

bypass invalid SSL certificate in .net core

In .NetCore, you can add the following code snippet at services configure method , I added a check to make sure only that we by pass the SSL certificate in development environment only

services.AddHttpClient("HttpClientName", client => {
// code to configure headers etc..
}).ConfigurePrimaryHttpMessageHandler(() => {
                  var handler = new HttpClientHandler();
                  if (hostingEnvironment.IsDevelopment())
                  {
                      handler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => { return true; };
                  }
                  return handler;
              });

Passing a variable to a powershell script via command line

Using param to name the parameters allows you to ignore the order of the parameters:

ParamEx.ps1

# Show how to handle command line parameters in Windows PowerShell
param(
  [string]$FileName,
  [string]$Bogus
)
write-output 'This is param FileName:'+$FileName
write-output 'This is param Bogus:'+$Bogus

ParaEx.bat

rem Notice that named params mean the order of params can be ignored
powershell -File .\ParamEx.ps1 -Bogus FooBar -FileName "c:\windows\notepad.exe"

Batch script: how to check for admin rights

I have two ways of checking for privileged access, both are pretty reliable, and very portable across almost every windows version.

1. Method

set guid=%random%%random%-%random%-%random%-%random%-%random%%random%%random%

mkdir %WINDIR%\%guid%>nul 2>&1
rmdir %WINDIR%\%guid%>nul 2>&1

IF %ERRORLEVEL%==0 (
    ECHO PRIVILEGED!
) ELSE (
    ECHO NOT PRIVILEGED!
)

This is one of the most reliable methods, because of its simplicity, and the behavior of this very primitive command is very unlikely to change. That is not the case of other built-in CLI tools like net session that can be disabled by admin/network policies, or commands like fsutils that changed the output on Windows 10.

* Works on XP and later

2. Method

REG ADD HKLM /F>nul 2>&1

IF %ERRORLEVEL%==0 (
    ECHO PRIVILEGED!
) ELSE (
    ECHO NOT PRIVILEGED!
)

Sometimes you don't like the idea of touching the user disk, even if it is as inoffensive as using fsutils or creating a empty folder, is it unprovable but it can result in a catastrophic failure if something goes wrong. In this scenario you can just check the registry for privileges.

For this you can try to create a key on HKEY_LOCAL_MACHINE using default permissions you'll get Access Denied and the ERRORLEVEL == 1, but if you run as Admin, it will print "command executed successfully" and ERRORLEVEL == 0. Since the key already exists it have no effect on the registry. This is probably the fastest way, and the REG is there for a long time.

* It's not avaliable on pre NT (Win 9X).

* Works on XP and later


Working example

A script that clear the temp folder

_x000D_
_x000D_
@echo off_x000D_
:main_x000D_
    echo._x000D_
    echo. Clear Temp Files script_x000D_
    echo._x000D_
_x000D_
    call :requirePrivilegies_x000D_
_x000D_
    rem Do something that require privilegies_x000D_
_x000D_
    echo. _x000D_
    del %temp%\*.*_x000D_
    echo. End!_x000D_
_x000D_
    pause>nul_x000D_
goto :eof_x000D_
_x000D_
_x000D_
:requirePrivilegies_x000D_
    set guid=%random%%random%-%random%-%random%-%random%-%random%%random%%random%_x000D_
    mkdir %WINDIR%\%guid%>nul 2>&1_x000D_
    rmdir %WINDIR%\%guid%>nul 2>&1_x000D_
    IF NOT %ERRORLEVEL%==0 (_x000D_
        echo ########## ERROR: ADMINISTRATOR PRIVILEGES REQUIRED ###########_x000D_
        echo # This script must be run as administrator to work properly!  #_x000D_
        echo # Right click on the script and select "Run As Administrator" #_x000D_
        echo ###############################################################_x000D_
        pause>nul_x000D_
        exit_x000D_
    )_x000D_
goto :eof
_x000D_
_x000D_
_x000D_

What is the difference between Bower and npm?

All package managers have many downsides. You just have to pick which you can live with.

History

npm started out managing node.js modules (that's why packages go into node_modules by default), but it works for the front-end too when combined with Browserify or webpack.

Bower is created solely for the front-end and is optimized with that in mind.

Size of repo

npm is much, much larger than bower, including general purpose JavaScript (like country-data for country information or sorts for sorting functions that is usable on the front end or the back end).

Bower has a much smaller amount of packages.

Handling of styles etc

Bower includes styles etc.

npm is focused on JavaScript. Styles are either downloaded separately or required by something like npm-sass or sass-npm.

Dependency handling

The biggest difference is that npm does nested dependencies (but is flat by default) while Bower requires a flat dependency tree (puts the burden of dependency resolution on the user).

A nested dependency tree means that your dependencies can have their own dependencies which can have their own, and so on. This allows for two modules to require different versions of the same dependency and still work. Note since npm v3, the dependency tree will be flat by default (saving space) and only nest where needed, e.g., if two dependencies need their own version of Underscore.

Some projects use both: they use Bower for front-end packages and npm for developer tools like Yeoman, Grunt, Gulp, JSHint, CoffeeScript, etc.


Resources

How do I find out if the GPS of an Android device is enabled

yes GPS settings cannot be changed programatically any more as they are privacy settings and we have to check if they are switched on or not from the program and handle it if they are not switched on. you can notify the user that GPS is turned off and use something like this to show the settings screen to the user if you want.

Check if location providers are available

    String provider = Settings.Secure.getString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
    if(provider != null){
        Log.v(TAG, " Location providers: "+provider);
        //Start searching for location and update the location text when update available
        startFetchingLocation();
    }else{
        // Notify users and show settings if they want to enable GPS
    }

If the user want to enable GPS you may show the settings screen in this way.

Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivityForResult(intent, REQUEST_CODE);

And in your onActivityResult you can see if the user has enabled it or not

    protected void onActivityResult(int requestCode, int resultCode, Intent data){
        if(requestCode == REQUEST_CODE && resultCode == 0){
            String provider = Settings.Secure.getString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
            if(provider != null){
                Log.v(TAG, " Location providers: "+provider);
                //Start searching for location and update the location text when update available. 
// Do whatever you want
                startFetchingLocation();
            }else{
                //Users did not switch on the GPS
            }
        }
    }

Thats one way to do it and i hope it helps. Let me know if I am doing anything wrong.

best way to create object

Depends on your requirment, but the most effective way to create is:

 Product obj = new Product
            {
                ID = 21,
                Price = 200,
                Category = "XY",
                Name = "SKR",
            };

Comments in Android Layout xml

If you want to comment in Android Studio simply press:

Ctrl + / on Windows/Linux

Cmd + / on Mac.

This works in XML files such as strings.xml as well as in code files like MainActivity.java.

Reading Excel file using node.js

There are a few different libraries doing parsing of Excel files (.xlsx). I will list two projects I find interesting and worth looking into.

Node-xlsx

Excel parser and builder. It's kind of a wrapper for a popular project JS-XLSX, which is a pure javascript implementation from the Office Open XML spec.

node-xlsx project page

Example for parsing file

var xlsx = require('node-xlsx');

var obj = xlsx.parse(__dirname + '/myFile.xlsx'); // parses a file

var obj = xlsx.parse(fs.readFileSync(__dirname + '/myFile.xlsx')); // parses a buffer

ExcelJS

Read, manipulate and write spreadsheet data and styles to XLSX and JSON. It's an active project. At the time of writing the latest commit was 9 hours ago. I haven't tested this myself, but the api looks extensive with a lot of possibilites.

exceljs project page

Code example:

// read from a file
var workbook = new Excel.Workbook();
workbook.xlsx.readFile(filename)
    .then(function() {
        // use workbook
    });

// pipe from stream
var workbook = new Excel.Workbook();
stream.pipe(workbook.xlsx.createInputStream());

How to create relationships in MySQL

If the tables are innodb you can create it like this:

CREATE TABLE accounts(
    account_id INT NOT NULL AUTO_INCREMENT,
    customer_id INT( 4 ) NOT NULL ,
    account_type ENUM( 'savings', 'credit' ) NOT NULL,
    balance FLOAT( 9 ) NOT NULL,
    PRIMARY KEY ( account_id ), 
    FOREIGN KEY (customer_id) REFERENCES customers(customer_id) 
) ENGINE=INNODB;

You have to specify that the tables are innodb because myisam engine doesn't support foreign key. Look here for more info.

JUNIT Test class in Eclipse - java.lang.ClassNotFoundException

I add this answer as my solution review from the above.

  1. You simply edit the file .project in the main project folder. Use a proper XML Editor otherwise you will get a fatal error from Eclipse that stats you can not open this project.
  2. I made my project nature Javaby adding this <nature>org.eclipse.jdt.core.javanature</nature> to <natures></natures>.
  3. I then added those lines correctly indented <buildCommand><name>org.eclipse.jdt.core.javabuilder</name><arguments></arguments></buildCommand> to <buildSpec></buildSpec>.
  4. Run as JUnit ... Success

Rename multiple files by replacing a particular pattern in the filenames using a shell script

You can try this:

for file in *.jpg;
do
  mv $file $somestring_${file:((-7))}
done

You can see "parameter expansion" in man bash to understand the above better.

Rename Pandas DataFrame Index

You can also use Index.set_names as follows:

In [25]: x = pd.DataFrame({'year':[1,1,1,1,2,2,2,2],
   ....:                   'country':['A','A','B','B','A','A','B','B'],
   ....:                   'prod':[1,2,1,2,1,2,1,2],
   ....:                   'val':[10,20,15,25,20,30,25,35]})

In [26]: x = x.set_index(['year','country','prod']).squeeze()

In [27]: x
Out[27]: 
year  country  prod
1     A        1       10
               2       20
      B        1       15
               2       25
2     A        1       20
               2       30
      B        1       25
               2       35
Name: val, dtype: int64
In [28]: x.index = x.index.set_names('foo', level=1)

In [29]: x
Out[29]: 
year  foo  prod
1     A    1       10
           2       20
      B    1       15
           2       25
2     A    1       20
           2       30
      B    1       25
           2       35
Name: val, dtype: int64

Calculating moving average

Here is example code showing how to compute a centered moving average and a trailing moving average using the rollmean function from the zoo package.

library(tidyverse)
library(zoo)

some_data = tibble(day = 1:10)
# cma = centered moving average
# tma = trailing moving average
some_data = some_data %>%
    mutate(cma = rollmean(day, k = 3, fill = NA)) %>%
    mutate(tma = rollmean(day, k = 3, fill = NA, align = "right"))
some_data
#> # A tibble: 10 x 3
#>      day   cma   tma
#>    <int> <dbl> <dbl>
#>  1     1    NA    NA
#>  2     2     2    NA
#>  3     3     3     2
#>  4     4     4     3
#>  5     5     5     4
#>  6     6     6     5
#>  7     7     7     6
#>  8     8     8     7
#>  9     9     9     8
#> 10    10    NA     9

Where is jarsigner?

%JAVA_HOME%\bin\jarsigner

You can find jarsigner there. Install jdk first.

Implementing a Custom Error page on an ASP.Net website

<customErrors defaultRedirect="~/404.aspx" mode="On">
    <error statusCode="404" redirect="~/404.aspx"/>
</customErrors>

Code above is only for "Page Not Found Error-404" if file extension is known(.html,.aspx etc)

Beside it you also have set Customer Errors for extension not known or not correct as

.aspwx or .vivaldo. You have to add httperrors settings in web.config

<httpErrors  errorMode="Custom"> 
       <error statusCode="404" prefixLanguageFilePath="" path="/404.aspx"         responseMode="Redirect" />
</httpErrors>
<modules runAllManagedModulesForAllRequests="true"/>

it must be inside the <system.webServer> </system.webServer>

How do I disable form resizing for users?

Change this property and try this at design time:

FormBorderStyle = FormBorderStyle.FixedDialog;

Designer view before the change:

Enter image description here

When use ResponseEntity<T> and @RestController for Spring RESTful applications

ResponseEntity is meant to represent the entire HTTP response. You can control anything that goes into it: status code, headers, and body.

@ResponseBody is a marker for the HTTP response body and @ResponseStatus declares the status code of the HTTP response.

@ResponseStatus isn't very flexible. It marks the entire method so you have to be sure that your handler method will always behave the same way. And you still can't set the headers. You'd need the HttpServletResponse or a HttpHeaders parameter.

Basically, ResponseEntity lets you do more.

Passing arrays as url parameter

This isn't a direct answer as this has already been answered, but everyone was talking about sending the data, but nobody really said what you do when it gets there, and it took me a good half an hour to work it out. So I thought I would help out here.

I will repeat this bit

$data = array(
'cat' => 'moggy',
'dog' => 'mutt'
);
$query = http_build_query(array('mydata' => $data));
$query=urlencode($query);

Obviously you would format it better than this www.someurl.com?x=$query

And to get the data back

parse_str($_GET['x']);
echo $mydata['dog'];
echo $mydata['cat'];

How to disable XDebug

I renamed the config file and restarted server:

$ mv /etc/php/7.0/fpm/conf.d/20-xdebug.ini /etc/php/7.0/fpm/conf.d/20-xdebug.ini.bak

$ sudo service php7.0-fpm restart && sudo service nginx restart

It did work for me.

TensorFlow not found using pip

Here is my Environment (Windows 10 with NVIDIA GPU). I wanted to install TensorFlow 1.12-gpu and failed multiple times but was able to solve by following the below approach.

This is to help Installing TensorFlow-GPU on Windows 10 Systems

Steps:

  1. Make sure you have NVIDIA graphic card

a. Go to windows explorer, open device manager-->check “Display Adaptors”-->it will show (ex. NVIDIA GeForce) if you have GPU else it will show “HD Graphics”

b. If the GPU is AMD’s then tensorflow doesn’t support AMD’s GPU

  1. If you have a GPU, check whether the GPU supports CUDA features or not.

a. If you find your GPU model at this link, then it supports CUDA.

b. If you don’t have CUDA enabled GPU, then you can install only tensorflow (without gpu)

  1. Tensorflow requires python-64bit version. Uninstall any python dependencies

a. Go to control panel-->search for “Programs and Features”, and search “python”

b. Uninstall things like anaconda and any pythons related plugins. These dependencies might interfere with the tensorflow-GPU installation.

c. Make sure python is uninstalled. Open a command prompt and type “python”, if it throws an error, then your system has no python and your can proceed to freshly install python

  1. Install python freshly

a.TF1.12 supports upto Python 3.6.6. Click here to download Windows x86-64 executable installer

b. While installing, select “Add Python 3.6 to PATH” and then click “Install Now”.

enter image description here

c. After successful installation of python, the installation window provides an option for disabling path length limit which is one of the root-cause of Tensorflow build/Installation issues in Windows 10 environment. Click “Disable path length limit” and follow the instructions to complete the installation.

enter image description here

d. Verify whether python installed correctly. Open a command prompt and type “python”. It should show the version of Python.

enter image description here

  1. Install Visual Studio

Visual Studio 2017 Community

a. Click the "Visual Studio Link" above.Download Visual Studio 2017 Community.

b. Under “Visual Studio IDE” on the left, select “community 2017” and download it

c. During installation, Select “Desktop development with C++” and install

  1. CUDA 9.0 toolkit

https://developer.nvidia.com/cuda-90-download-archive?target_os=Windows&target_arch=x86_64&target_version=10&target_type=exelocal

a. Click "Link to CUDA 9.0 toolkit" above, download “Base Installer”

b. Install CUDA 9.0

  1. Install cuDNN

https://developer.nvidia.com/cudnn

a. Click "Link to Install cuDNN" and select “I Agree To the Terms of the cuDNN Software License Agreement”

b. Register for login, check your email to verify email address

c. Click “cuDNN Download” and fill a short survey to reach “cuDNN Download” page

d. Select “ I Agree To the Terms of the cuDNN Software License Agreement”

e. Select “Download cuDNN v7.5.0 (Feb 21, 2019), for CUDA 9.0"

f. In the dropdown, click “cuDNN Library for Windows 10” and download

g. Go to the folder where the file was downloaded, extract the files

enter image description here

h. Add three folders (bin, include, lib) inside the extracted file to environment

enter image description here

i. Type “environment” in windows 10 search bar and locate the “Environment Variables” and click “Path” in “User variable” section and click “Edit” and then select “New” and add those three paths to three “cuda” folders

j. Close the “Environmental Variables” window.

  1. Install tensorflow-gpu

a. Open a command prompt and type “pip install --upgrade tensorflow-gpu”

b. It will install tensorflow-gpu

  1. Check whether it was correctly installed or not

a. Type “python” at the command prompt

b. Type “import tensorflow as tf

c. hello=tf.constant(‘Hello World!’)

d. sess=tf.Session()

e. print(sess.run(hello)) -->Hello World!

  1. Test whether tensorflow is using GPU

a. from tensorflow.python.client import device_lib print(device_lib.list_local_devices())

b. print(device_lib.list_local_devices())

How to determine the encoding of text?

If you know the some content of the file you can try to decode it with several encoding and see which is missing. In general there is no way since a text file is a text file and those are stupid ;)

Use grep --exclude/--include syntax to not grep through certain files

find and xargs are your friends. Use them to filter the file list rather than grep's --exclude

Try something like

find . -not -name '*.png' -o -type f -print | xargs grep -icl "foo="

The advantage of getting used to this, is that it is expandable to other use cases, for example to count the lines in all non-png files:

find . -not -name '*.png' -o -type f -print | xargs wc -l

To remove all non-png files:

find . -not -name '*.png' -o -type f -print | xargs rm

etc.

As pointed out in the comments, if some files may have spaces in their names, use -print0 and xargs -0 instead.

jQuery: Change button text on click

$('.SeeMore2').click(function(){
    var $this = $(this);
    $this.toggleClass('SeeMore2');
    if($this.hasClass('SeeMore2')){
        $this.text('See More');         
    } else {
        $this.text('See Less');
    }
});

This should do it. You have to make sure you toggle the correct class and take out the "." from the hasClass

http://jsfiddle.net/V4u5X/2/

How do I force git pull to overwrite everything on every pull?

If you haven't commit the local changes yet since the last pull/clone, you can use:

git checkout *
git pull

checkout will clear your local changes with the last local commit, and pull will sincronize it to the remote repository

"query function not defined for Select2 undefined error"

I also had this problem make sure that you don't initialize the select2 twice.

Git merge without auto commit

If you only want to commit all the changes in one commit as if you typed yourself, --squash will do too

$ git merge --squash v1.0
$ git commit

How to get today's Date?

If you want midnight (0:00am) for the current date, you can just use the default constructor and zero out the time portions:

Date today = new Date();
today.setHours(0); today.setMinutes(0); today.setSeconds(0);

edit: update with Calendar since those methods are deprecated

Calendar today = Calendar.getInstance();
today.clear(Calendar.HOUR); today.clear(Calendar.MINUTE); today.clear(Calendar.SECOND);
Date todayDate = today.getTime();

How to change maven java home

The best way to force a specific JVM for MAVEN is to create a system wide file loaded by the mvn script.

This file is /etc/mavenrc and it must declare a JAVA_HOME environment variable pointing to your specific JVM.

Example:

export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64

If the file exists, it's loaded.

Here is an extract of the mvn script in order to understand :

  if [ -f /etc/mavenrc ] ; then
    . /etc/mavenrc
  fi

  if [ -f "$HOME/.mavenrc" ] ; then
    . "$HOME/.mavenrc"
  fi

Alternately, the same content can be written in ~/.mavenrc

unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING error

Change your code to.

<?php
$sqlupdate1 = "UPDATE table SET commodity_quantity=".$qty."WHERE user=".$rows['user'];
?>

There was syntax error in your query.

How to select the first element in the dropdown using jquery?

I'm answering because the previous answers have stopped working with the latest version of jQuery. I don't know when it stopped working, but the documentation says that .prop() has been the preferred method to get/set properties since jQuery 1.6.

This is how I got it to work (with jQuery 3.2.1):

$('select option:nth-child(1)').prop("selected", true);

I am using knockoutjs and the change bindings weren't firing with the above code, so I added .change() to the end.

Here's what I needed for my solution:

$('select option:nth-child(1)').prop("selected", true).change();

See .prop() notes in the documentation here: http://api.jquery.com/prop/

Passing JavaScript array to PHP through jQuery $.ajax

data: { activitiesArray: activities },

That's it! Now you can access it in PHP:

<?php $myArray = $_REQUEST['activitiesArray']; ?>

CocoaPods Errors on Project Build

Had the same issue saying /Pods/Pods-resources.sh: No such file or directory even after files etc related to pods were removed.

Got rid of it by going to target->Build phases and then removing the build phase "Copy Pod Resources".

CSS rotation cross browser with jquery.animate()

jQuery transit will probably make your life easier if you are dealing with CSS3 animations through jQuery.

EDIT March 2014 (because my advice has constantly been up and down voted since I posted it)

Let me explain why I was initially hinting towards the plugin above:

Updating the DOM on each step (i.e. $.animate ) is not ideal in terms of performance. It works, but will most probably be slower than pure CSS3 transitions or CSS3 animations.

This is mainly because the browser gets a chance to think ahead if you indicate what the transition is going to look like from start to end.

To do so, you can for example create a CSS class for each state of the transition and only use jQuery to toggle the animation state.

This is generally quite neat as you can tweak you animations alongside the rest of your CSS instead of mixing it up with your business logic:

// initial state
.eye {
   -webkit-transform: rotate(45deg);
   -moz-transform: rotate(45deg);
   transform: rotate(45deg);
   // etc.

   // transition settings
   -webkit-transition: -webkit-transform 1s linear 0.2s;
   -moz-transition: -moz-transform 1s linear 0.2s;
   transition: transform 1s linear 0.2s;
   // etc.
}

// open state    
.eye.open {

   transform: rotate(90deg);
}

// Javascript
$('.eye').on('click', function () { $(this).addClass('open'); });

If any of the transform parameters is dynamic you can of course use the style attribute instead:

$('.eye').on('click', function () { 
    $(this).css({ 
        -webkit-transition: '-webkit-transform 1s ease-in',
        -moz-transition: '-moz-transform 1s ease-in',
        // ...

        // note that jQuery will vendor prefix the transform property automatically
        transform: 'rotate(' + (Math.random()*45+45).toFixed(3) + 'deg)'
    }); 
});

A lot more detailed information on CSS3 transitions on MDN.

HOWEVER There are a few other things to keep in mind and all this can get a bit tricky if you have complex animations, chaining etc. and jQuery Transit just does all the tricky bits under the hood:

$('.eye').transit({ rotate: '90deg'}); // easy huh ?

What does @media screen and (max-width: 1024px) mean in CSS?

It targets some specified feature to execute some other codes...

For example:

@media all and (max-width: 600px) {
  .navigation {
    -webkit-flex-flow: column wrap;
    flex-flow: column wrap;
    padding: 0;

  }

the above snippet say if the device that run this program have screen with 600px or less than 600px width, in this case our program must execute this part .

Wait until a process ends

I do the following in my application:

Process process = new Process();
process.StartInfo.FileName = executable;
process.StartInfo.Arguments = arguments;
process.StartInfo.ErrorDialog = true;
process.StartInfo.WindowStyle = ProcessWindowStyle.Minimized;
process.Start();
process.WaitForExit(1000 * 60 * 5);    // Wait up to five minutes.

There are a few extra features in there which you might find useful...

SQL query return data from multiple tables

Part 1 - Joins and Unions

This answer covers:

  1. Part 1
    • Joining two or more tables using an inner join (See the wikipedia entry for additional info)
    • How to use a union query
    • Left and Right Outer Joins (this stackOverflow answer is excellent to describe types of joins)
    • Intersect queries (and how to reproduce them if your database doesn't support them) - this is a function of SQL-Server (see info) and part of the reason I wrote this whole thing in the first place.
  2. Part 2
    • Subqueries - what they are, where they can be used and what to watch out for
    • Cartesian joins AKA - Oh, the misery!

There are a number of ways to retrieve data from multiple tables in a database. In this answer, I will be using ANSI-92 join syntax. This may be different to a number of other tutorials out there which use the older ANSI-89 syntax (and if you are used to 89, may seem much less intuitive - but all I can say is to try it) as it is much easier to understand when the queries start getting more complex. Why use it? Is there a performance gain? The short answer is no, but it is easier to read once you get used to it. It is easier to read queries written by other folks using this syntax.

I am also going to use the concept of a small caryard which has a database to keep track of what cars it has available. The owner has hired you as his IT Computer guy and expects you to be able to drop him the data that he asks for at the drop of a hat.

I have made a number of lookup tables that will be used by the final table. This will give us a reasonable model to work from. To start off, I will be running my queries against an example database that has the following structure. I will try to think of common mistakes that are made when starting out and explain what goes wrong with them - as well as of course showing how to correct them.

The first table is simply a color listing so that we know what colors we have in the car yard.

mysql> create table colors(id int(3) not null auto_increment primary key, 
    -> color varchar(15), paint varchar(10));
Query OK, 0 rows affected (0.01 sec)

mysql> show columns from colors;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(3)      | NO   | PRI | NULL    | auto_increment |
| color | varchar(15) | YES  |     | NULL    |                |
| paint | varchar(10) | YES  |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+
3 rows in set (0.01 sec)

mysql> insert into colors (color, paint) values ('Red', 'Metallic'), 
    -> ('Green', 'Gloss'), ('Blue', 'Metallic'), 
    -> ('White' 'Gloss'), ('Black' 'Gloss');
Query OK, 5 rows affected (0.00 sec)
Records: 5  Duplicates: 0  Warnings: 0

mysql> select * from colors;
+----+-------+----------+
| id | color | paint    |
+----+-------+----------+
|  1 | Red   | Metallic |
|  2 | Green | Gloss    |
|  3 | Blue  | Metallic |
|  4 | White | Gloss    |
|  5 | Black | Gloss    |
+----+-------+----------+
5 rows in set (0.00 sec)

The brands table identifies the different brands of the cars out caryard could possibly sell.

mysql> create table brands (id int(3) not null auto_increment primary key, 
    -> brand varchar(15));
Query OK, 0 rows affected (0.01 sec)

mysql> show columns from brands;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(3)      | NO   | PRI | NULL    | auto_increment |
| brand | varchar(15) | YES  |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+
2 rows in set (0.01 sec)

mysql> insert into brands (brand) values ('Ford'), ('Toyota'), 
    -> ('Nissan'), ('Smart'), ('BMW');
Query OK, 5 rows affected (0.00 sec)
Records: 5  Duplicates: 0  Warnings: 0

mysql> select * from brands;
+----+--------+
| id | brand  |
+----+--------+
|  1 | Ford   |
|  2 | Toyota |
|  3 | Nissan |
|  4 | Smart  |
|  5 | BMW    |
+----+--------+
5 rows in set (0.00 sec)

The model table will cover off different types of cars, it is going to be simpler for this to use different car types rather than actual car models.

mysql> create table models (id int(3) not null auto_increment primary key, 
    -> model varchar(15));
Query OK, 0 rows affected (0.01 sec)

mysql> show columns from models;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(3)      | NO   | PRI | NULL    | auto_increment |
| model | varchar(15) | YES  |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+
2 rows in set (0.00 sec)

mysql> insert into models (model) values ('Sports'), ('Sedan'), ('4WD'), ('Luxury');
Query OK, 4 rows affected (0.00 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> select * from models;
+----+--------+
| id | model  |
+----+--------+
|  1 | Sports |
|  2 | Sedan  |
|  3 | 4WD    |
|  4 | Luxury |
+----+--------+
4 rows in set (0.00 sec)

And finally, to tie up all these other tables, the table that ties everything together. The ID field is actually the unique lot number used to identify cars.

mysql> create table cars (id int(3) not null auto_increment primary key, 
    -> color int(3), brand int(3), model int(3));
Query OK, 0 rows affected (0.01 sec)

mysql> show columns from cars;
+-------+--------+------+-----+---------+----------------+
| Field | Type   | Null | Key | Default | Extra          |
+-------+--------+------+-----+---------+----------------+
| id    | int(3) | NO   | PRI | NULL    | auto_increment |
| color | int(3) | YES  |     | NULL    |                |
| brand | int(3) | YES  |     | NULL    |                |
| model | int(3) | YES  |     | NULL    |                |
+-------+--------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

mysql> insert into cars (color, brand, model) values (1,2,1), (3,1,2), (5,3,1), 
    -> (4,4,2), (2,2,3), (3,5,4), (4,1,3), (2,2,1), (5,2,3), (4,5,1);
Query OK, 10 rows affected (0.00 sec)
Records: 10  Duplicates: 0  Warnings: 0

mysql> select * from cars;
+----+-------+-------+-------+
| id | color | brand | model |
+----+-------+-------+-------+
|  1 |     1 |     2 |     1 |
|  2 |     3 |     1 |     2 |
|  3 |     5 |     3 |     1 |
|  4 |     4 |     4 |     2 |
|  5 |     2 |     2 |     3 |
|  6 |     3 |     5 |     4 |
|  7 |     4 |     1 |     3 |
|  8 |     2 |     2 |     1 |
|  9 |     5 |     2 |     3 |
| 10 |     4 |     5 |     1 |
+----+-------+-------+-------+
10 rows in set (0.00 sec)

This will give us enough data (I hope) to cover off the examples below of different types of joins and also give enough data to make them worthwhile.

So getting into the grit of it, the boss wants to know The IDs of all the sports cars he has.

This is a simple two table join. We have a table that identifies the model and the table with the available stock in it. As you can see, the data in the model column of the cars table relates to the models column of the cars table we have. Now, we know that the models table has an ID of 1 for Sports so lets write the join.

select
    ID,
    model
from
    cars
        join models
            on model=ID

So this query looks good right? We have identified the two tables and contain the information we need and use a join that correctly identifies what columns to join on.

ERROR 1052 (23000): Column 'ID' in field list is ambiguous

Oh noes! An error in our first query! Yes, and it is a plum. You see, the query has indeed got the right columns, but some of them exist in both tables, so the database gets confused about what actual column we mean and where. There are two solutions to solve this. The first is nice and simple, we can use tableName.columnName to tell the database exactly what we mean, like this:

select
    cars.ID,
    models.model
from
    cars
        join models
            on cars.model=models.ID

+----+--------+
| ID | model  |
+----+--------+
|  1 | Sports |
|  3 | Sports |
|  8 | Sports |
| 10 | Sports |
|  2 | Sedan  |
|  4 | Sedan  |
|  5 | 4WD    |
|  7 | 4WD    |
|  9 | 4WD    |
|  6 | Luxury |
+----+--------+
10 rows in set (0.00 sec)

The other is probably more often used and is called table aliasing. The tables in this example have nice and short simple names, but typing out something like KPI_DAILY_SALES_BY_DEPARTMENT would probably get old quickly, so a simple way is to nickname the table like this:

select
    a.ID,
    b.model
from
    cars a
        join models b
            on a.model=b.ID

Now, back to the request. As you can see we have the information we need, but we also have information that wasn't asked for, so we need to include a where clause in the statement to only get the Sports cars as was asked. As I prefer the table alias method rather than using the table names over and over, I will stick to it from this point onwards.

Clearly, we need to add a where clause to our query. We can identify Sports cars either by ID=1 or model='Sports'. As the ID is indexed and the primary key (and it happens to be less typing), lets use that in our query.

select
    a.ID,
    b.model
from
    cars a
        join models b
            on a.model=b.ID
where
    b.ID=1

+----+--------+
| ID | model  |
+----+--------+
|  1 | Sports |
|  3 | Sports |
|  8 | Sports |
| 10 | Sports |
+----+--------+
4 rows in set (0.00 sec)

Bingo! The boss is happy. Of course, being a boss and never being happy with what he asked for, he looks at the information, then says I want the colors as well.

Okay, so we have a good part of our query already written, but we need to use a third table which is colors. Now, our main information table cars stores the car color ID and this links back to the colors ID column. So, in a similar manner to the original, we can join a third table:

select
    a.ID,
    b.model
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
where
    b.ID=1

+----+--------+
| ID | model  |
+----+--------+
|  1 | Sports |
|  3 | Sports |
|  8 | Sports |
| 10 | Sports |
+----+--------+
4 rows in set (0.00 sec)

Damn, although the table was correctly joined and the related columns were linked, we forgot to pull in the actual information from the new table that we just linked.

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
where
    b.ID=1

+----+--------+-------+
| ID | model  | color |
+----+--------+-------+
|  1 | Sports | Red   |
|  8 | Sports | Green |
| 10 | Sports | White |
|  3 | Sports | Black |
+----+--------+-------+
4 rows in set (0.00 sec)

Right, that's the boss off our back for a moment. Now, to explain some of this in a little more detail. As you can see, the from clause in our statement links our main table (I often use a table that contains information rather than a lookup or dimension table. The query would work just as well with the tables all switched around, but make less sense when we come back to this query to read it in a few months time, so it is often best to try to write a query that will be nice and easy to understand - lay it out intuitively, use nice indenting so that everything is as clear as it can be. If you go on to teach others, try to instill these characteristics in their queries - especially if you will be troubleshooting them.

It is entirely possible to keep linking more and more tables in this manner.

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=1

While I forgot to include a table where we might want to join more than one column in the join statement, here is an example. If the models table had brand-specific models and therefore also had a column called brand which linked back to the brands table on the ID field, it could be done as this:

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
            and b.brand=d.ID
where
    b.ID=1

You can see, the query above not only links the joined tables to the main cars table, but also specifies joins between the already joined tables. If this wasn't done, the result is called a cartesian join - which is dba speak for bad. A cartesian join is one where rows are returned because the information doesn't tell the database how to limit the results, so the query returns all the rows that fit the criteria.

So, to give an example of a cartesian join, lets run the following query:

select
    a.ID,
    b.model
from
    cars a
        join models b

+----+--------+
| ID | model  |
+----+--------+
|  1 | Sports |
|  1 | Sedan  |
|  1 | 4WD    |
|  1 | Luxury |
|  2 | Sports |
|  2 | Sedan  |
|  2 | 4WD    |
|  2 | Luxury |
|  3 | Sports |
|  3 | Sedan  |
|  3 | 4WD    |
|  3 | Luxury |
|  4 | Sports |
|  4 | Sedan  |
|  4 | 4WD    |
|  4 | Luxury |
|  5 | Sports |
|  5 | Sedan  |
|  5 | 4WD    |
|  5 | Luxury |
|  6 | Sports |
|  6 | Sedan  |
|  6 | 4WD    |
|  6 | Luxury |
|  7 | Sports |
|  7 | Sedan  |
|  7 | 4WD    |
|  7 | Luxury |
|  8 | Sports |
|  8 | Sedan  |
|  8 | 4WD    |
|  8 | Luxury |
|  9 | Sports |
|  9 | Sedan  |
|  9 | 4WD    |
|  9 | Luxury |
| 10 | Sports |
| 10 | Sedan  |
| 10 | 4WD    |
| 10 | Luxury |
+----+--------+
40 rows in set (0.00 sec)

Good god, that's ugly. However, as far as the database is concerned, it is exactly what was asked for. In the query, we asked for for the ID from cars and the model from models. However, because we didn't specify how to join the tables, the database has matched every row from the first table with every row from the second table.

Okay, so the boss is back, and he wants more information again. I want the same list, but also include 4WDs in it.

This however, gives us a great excuse to look at two different ways to accomplish this. We could add another condition to the where clause like this:

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=1
    or b.ID=3

While the above will work perfectly well, lets look at it differently, this is a great excuse to show how a union query will work.

We know that the following will return all the Sports cars:

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=1

And the following would return all the 4WDs:

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=3

So by adding a union all clause between them, the results of the second query will be appended to the results of the first query.

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=1
union all
select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=3

+----+--------+-------+
| ID | model  | color |
+----+--------+-------+
|  1 | Sports | Red   |
|  8 | Sports | Green |
| 10 | Sports | White |
|  3 | Sports | Black |
|  5 | 4WD    | Green |
|  7 | 4WD    | White |
|  9 | 4WD    | Black |
+----+--------+-------+
7 rows in set (0.00 sec)

As you can see, the results of the first query are returned first, followed by the results of the second query.

In this example, it would of course have been much easier to simply use the first query, but union queries can be great for specific cases. They are a great way to return specific results from tables from tables that aren't easily joined together - or for that matter completely unrelated tables. There are a few rules to follow however.

  • The column types from the first query must match the column types from every other query below.
  • The names of the columns from the first query will be used to identify the entire set of results.
  • The number of columns in each query must be the same.

Now, you might be wondering what the difference is between using union and union all. A union query will remove duplicates, while a union all will not. This does mean that there is a small performance hit when using union over union all but the results may be worth it - I won't speculate on that sort of thing in this though.

On this note, it might be worth noting some additional notes here.

  • If we wanted to order the results, we can use an order by but you can't use the alias anymore. In the query above, appending an order by a.ID would result in an error - as far as the results are concerned, the column is called ID rather than a.ID - even though the same alias has been used in both queries.
  • We can only have one order by statement, and it must be as the last statement.

For the next examples, I am adding a few extra rows to our tables.

I have added Holden to the brands table. I have also added a row into cars that has the color value of 12 - which has no reference in the colors table.

Okay, the boss is back again, barking requests out - *I want a count of each brand we carry and the number of cars in it!` - Typical, we just get to an interesting section of our discussion and the boss wants more work.

Rightyo, so the first thing we need to do is get a complete listing of possible brands.

select
    a.brand
from
    brands a

+--------+
| brand  |
+--------+
| Ford   |
| Toyota |
| Nissan |
| Smart  |
| BMW    |
| Holden |
+--------+
6 rows in set (0.00 sec)

Now, when we join this to our cars table we get the following result:

select
    a.brand
from
    brands a
        join cars b
            on a.ID=b.brand
group by
    a.brand

+--------+
| brand  |
+--------+
| BMW    |
| Ford   |
| Nissan |
| Smart  |
| Toyota |
+--------+
5 rows in set (0.00 sec)

Which is of course a problem - we aren't seeing any mention of the lovely Holden brand I added.

This is because a join looks for matching rows in both tables. As there is no data in cars that is of type Holden it isn't returned. This is where we can use an outer join. This will return all the results from one table whether they are matched in the other table or not:

select
    a.brand
from
    brands a
        left outer join cars b
            on a.ID=b.brand
group by
    a.brand

+--------+
| brand  |
+--------+
| BMW    |
| Ford   |
| Holden |
| Nissan |
| Smart  |
| Toyota |
+--------+
6 rows in set (0.00 sec)

Now that we have that, we can add a lovely aggregate function to get a count and get the boss off our backs for a moment.

select
    a.brand,
    count(b.id) as countOfBrand
from
    brands a
        left outer join cars b
            on a.ID=b.brand
group by
    a.brand

+--------+--------------+
| brand  | countOfBrand |
+--------+--------------+
| BMW    |            2 |
| Ford   |            2 |
| Holden |            0 |
| Nissan |            1 |
| Smart  |            1 |
| Toyota |            5 |
+--------+--------------+
6 rows in set (0.00 sec)

And with that, away the boss skulks.

Now, to explain this in some more detail, outer joins can be of the left or right type. The Left or Right defines which table is fully included. A left outer join will include all the rows from the table on the left, while (you guessed it) a right outer join brings all the results from the table on the right into the results.

Some databases will allow a full outer join which will bring back results (whether matched or not) from both tables, but this isn't supported in all databases.

Now, I probably figure at this point in time, you are wondering whether or not you can merge join types in a query - and the answer is yes, you absolutely can.

select
    b.brand,
    c.color,
    count(a.id) as countOfBrand
from
    cars a
        right outer join brands b
            on b.ID=a.brand
        join colors c
            on a.color=c.ID
group by
    a.brand,
    c.color

+--------+-------+--------------+
| brand  | color | countOfBrand |
+--------+-------+--------------+
| Ford   | Blue  |            1 |
| Ford   | White |            1 |
| Toyota | Black |            1 |
| Toyota | Green |            2 |
| Toyota | Red   |            1 |
| Nissan | Black |            1 |
| Smart  | White |            1 |
| BMW    | Blue  |            1 |
| BMW    | White |            1 |
+--------+-------+--------------+
9 rows in set (0.00 sec)

So, why is that not the results that were expected? It is because although we have selected the outer join from cars to brands, it wasn't specified in the join to colors - so that particular join will only bring back results that match in both tables.

Here is the query that would work to get the results that we expected:

select
    a.brand,
    c.color,
    count(b.id) as countOfBrand
from
    brands a
        left outer join cars b
            on a.ID=b.brand
        left outer join colors c
            on b.color=c.ID
group by
    a.brand,
    c.color

+--------+-------+--------------+
| brand  | color | countOfBrand |
+--------+-------+--------------+
| BMW    | Blue  |            1 |
| BMW    | White |            1 |
| Ford   | Blue  |            1 |
| Ford   | White |            1 |
| Holden | NULL  |            0 |
| Nissan | Black |            1 |
| Smart  | White |            1 |
| Toyota | NULL  |            1 |
| Toyota | Black |            1 |
| Toyota | Green |            2 |
| Toyota | Red   |            1 |
+--------+-------+--------------+
11 rows in set (0.00 sec)

As we can see, we have two outer joins in the query and the results are coming through as expected.

Now, how about those other types of joins you ask? What about Intersections?

Well, not all databases support the intersection but pretty much all databases will allow you to create an intersection through a join (or a well structured where statement at the least).

An Intersection is a type of join somewhat similar to a union as described above - but the difference is that it only returns rows of data that are identical (and I do mean identical) between the various individual queries joined by the union. Only rows that are identical in every regard will be returned.

A simple example would be as such:

select
    *
from
    colors
where
    ID>2
intersect
select
    *
from
    colors
where
    id<4

While a normal union query would return all the rows of the table (the first query returning anything over ID>2 and the second anything having ID<4) which would result in a full set, an intersect query would only return the row matching id=3 as it meets both criteria.

Now, if your database doesn't support an intersect query, the above can be easily accomlished with the following query:

select
    a.ID,
    a.color,
    a.paint
from
    colors a
        join colors b
            on a.ID=b.ID
where
    a.ID>2
    and b.ID<4

+----+-------+----------+
| ID | color | paint    |
+----+-------+----------+
|  3 | Blue  | Metallic |
+----+-------+----------+
1 row in set (0.00 sec)

If you wish to perform an intersection across two different tables using a database that doesn't inherently support an intersection query, you will need to create a join on every column of the tables.

Add content to a new open window

Here is what you can try

  • Write a function say init() inside mypage.html that do the html thing ( append or what ever)
  • instead of OpenWindow.document.write(output); call OpenWindow.init() when the dom is ready

So the parent window will have

    OpenWindow.onload = function(){
       OpenWindow.init('test');
    }

and in the child

    function init(txt){
        $('#test').text(txt);
    }

can not find module "@angular/material"

Please check Angular Getting started :)

  1. Install Angular Material and Angular CDK
  2. Animations - if you need
  3. Import the component modules

and enjoy the {{Angular}}

public static const in TypeScript

If you did want something that behaved more like a static constant value in modern browsers (in that it can't be changed by other code), you could add a get only accessor to the Library class (this will only work for ES5+ browsers and NodeJS):

export class Library {
    public static get BOOK_SHELF_NONE():string { return "None"; }
    public static get BOOK_SHELF_FULL():string { return "Full"; }   
}

var x = Library.BOOK_SHELF_NONE;
console.log(x);
Library.BOOK_SHELF_NONE = "Not Full";
x = Library.BOOK_SHELF_NONE;
console.log(x);

If you run it, you'll see how the attempt to set the BOOK_SHELF_NONE property to a new value doesn't work.

2.0

In TypeScript 2.0, you can use readonly to achieve very similar results:

export class Library {
    public static readonly BOOK_SHELF_NONE = "None";
    public static readonly BOOK_SHELF_FULL = "Full";
}

The syntax is a bit simpler and more obvious. However, the compiler prevents changes rather than the run time (unlike in the first example, where the change would not be allowed at all as demonstrated).

Increasing the maximum number of TCP/IP connections in Linux

In an application level, here are something a developer can do:

From server side:

  1. Check if load balancer(if you have),works correctly.

  2. Turn slow TCP timeouts into 503 Fast Immediate response, if you load balancer work correctly, it should pick the working resource to serve, and it's better than hanging there with unexpected error massages.

Eg: If you are using node server, u can use toobusy from npm. Implementation something like:

var toobusy = require('toobusy');
app.use(function(req, res, next) {
  if (toobusy()) res.send(503, "I'm busy right now, sorry.");
  else next();
});

Why 503? Here are some good insights for overload: http://ferd.ca/queues-don-t-fix-overload.html

We can do some work in client side too:

  1. Try to group calls in batch, reduce the traffic and total requests number b/w client and server.

  2. Try to build a cache mid-layer to handle unnecessary duplicates requests.

How to properly express JPQL "join fetch" with "where" clause as JPA 2 CriteriaQuery?

I will show visually the problem, using the great example from James answer and adding the alternative solution.

When you do the follow query, without the FETCH:

Select e from Employee e 
join e.phones p 
where p.areaCode = '613'

You will have the follow results from Employee as you expected:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613
1 James 6 416

But when you add the FETCH word on JOIN, this is what happens:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613

The generated SQL is the same for the two queries, but the Hibernate removes on memory the 416 register when you use WHERE on the FETCH join.

So, to bring all phones and apply the WHERE correctly, you need to have two JOINs: one for the WHERE and another for the FETCH. Like:

Select e from Employee e 
join e.phones p 
join fetch e.phones      //no alias, to not commit the mistake
where p.areaCode = '613'

Inserting a tab character into text using C#

There are several ways to do it. The simplest is using \t in your text. However, it's possible that \t doesn't work in some situations, like PdfReport nuget package.

Could not find com.android.tools.build:gradle:3.0.0-alpha1 in circle ci

Make sure you add following line in your top level build.gradle and that should fix it.

maven { url 'https://maven.google.com' }

I got exact same error you mentioned above, once I added this entry everything worked.

How to upgrade Git to latest version on macOS?

In order to keep both versions, I just changed the value of PATH environment variable by putting the new version's git path "/usr/local/git/bin/" at the beginning, it forces to use the newest version:

$ echo $PATH

/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin:/usr/local/git/bin/

$ git --version

git version 2.4.9 (Apple Git-60)

original value: /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin:/usr/local/git/bin/

new value: /usr/local/git/bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin

$ export PATH=/usr/local/git/bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin

$ git --version

git version 2.13.0

Convert from MySQL datetime to another format with PHP

SELECT 
 DATE_FORMAT(demo.dateFrom, '%e.%M.%Y') as dateFrom,
 DATE_FORMAT(demo.dateUntil, '%e.%M.%Y') as dateUntil
FROM demo

If you dont want to change every function in your PHP code, to show the expected date format, change it at the source - your database.

It is important to name the rows with the as operator as in the example above (as dateFrom, as dateUntil). The names you write there are the names, the rows will be called in your result.

The output of this example will be

[Day of the month, numeric (0..31)].[Month name (January..December)].[Year, numeric, four digits]

Example: 5.August.2015

Change the dots with the separator of choice and check the DATE_FORMAT(date,format) function for more date formats.

How to get rid of underline for Link component of React Router?

You can add style={{ textDecoration: 'none' }} in your Link component to remove the underline. You can also add more css in the style block e.g. style={{ textDecoration: 'none', color: 'white' }}.

<h1>
  <Link style={{ textDecoration: 'none', color: 'white' }} to="/getting-started">
    Get Started
  </Link>
</h1> 

How do I copy a range of formula values and paste them to a specific range in another sheet?

How about if you're copying each column in a sheet to different sheets? Example: row B of mysheet to row B of sheet1, row C of mysheet to row B of sheet 2...

reading a line from ifstream into a string variable

Use the std::getline() from <string>.

 istream & getline(istream & is,std::string& str)

So, for your case it would be:

std::getline(read,x);

What does "SyntaxError: Missing parentheses in call to 'print'" mean in Python?

I could also just add that I knew everything about the syntax change between Python2.7 and Python3, and my code was correctly written as print("string") and even print(f"string")...

But after some time of debugging I realized that my bash script was calling python like:

python file_name.py

which had the effect of calling my python script by default using python2.7 which gave the error. So I changed my bash script to:

python3 file_name.py

which of coarse uses python3 to run the script which fixed the error.

npm - "Can't find Python executable "python", you can set the PYTHON env variable."

One of the following solutions will work for you:

  1. npm config set python c:\Python\27\python.exe or set PYTHON=D:\Python\bin\Python.exe
  2. npm config set python D:\Library\Python\Python27\python.exe
  3. Let npm configure everything for you (takes forever to complete) npm --add-python-to-path='true' --debug install --global windows-build-tools (Must be executed via "Run As Administrator" PowerShell)

If not... Try to install the required package on your own (I did so, and it was node-sass, after installing it manually, the whole npm install was successfully completed

Sort array by firstname (alphabetically) in Javascript

You can use this for objects

transform(array: any[], field: string): any[] {
return array.sort((a, b) => a[field].toLowerCase() !== b[field].toLowerCase() ? a[field].toLowerCase() < b[field].toLowerCase() ? -1 : 1 : 0);}

ADB Shell Input Events

Also, if you want to send embedded spaces with the input command, use %s

adb shell input text 'this%sis%san%sexample'   

will yield

this is an example

being input.

% itself does not need escaping - only the special %s pair is treated specially. This leads of course to the obvious question of how to enter the literal string %s, which you would have to do with two separate commands.

Why fragments, and when to use fragments instead of activities?

Adding to above answers, I shall tell using example of an app I released on playstore.

This was the first app I developed when learning android there fore I worked only with activities There are multiple activity pages I think about 12. Most of these had content that could be reused in other pages yet I ended up with a separate activity page for almost every single click on the app. Once I learnt fragments I realised how all reusables could just be implemented and separate fragments and just be used with very few activities. My user may not see any difference, but the same can be done with lesser code besides fragments are light weight, apart from the reusability and modularity they offer.

Align text in JLabel to the right

To me, it seems as if your actual intention is to put different words on different lines. But let me answer your first question:

JLabel lab=new JLabel("text");
lab.setHorizontalAlignment(SwingConstants.LEFT);     

And if you have an image:

JLabel lab=new Jlabel("text");
lab.setIcon(new ImageIcon("path//img.png"));
lab.setHorizontalTextPosition(SwingConstants.LEFT);

But, I believe you want to make the label such that there are only 2 words on 1 line.

In that case try this:

String urText="<html>You can<br>use basic HTML<br>in Swing<br> components," 
   +"Hope<br> I helped!";
JLabel lac=new JLabel(urText);
lac.setAlignmentX(Component.RIGHT_ALIGNMENT);

How to convert a normal Git repository to a bare one?

In case you have a repository with few local checkedout branches /refs/heads/* and few remote branch branches remotes/origin/* AND if you want to convert this into a BARE repository with all branches in /refs/heads/*

you can do the following to save the history.

  1. create a bare repository
  2. cd into the local repository which has local checkedout branches and remote branches
  3. git push /path/to/bare/repo +refs/remotes/origin/:refs/heads/

How to check if a python module exists without importing it

Python2

To check if import can find something in python2, using imp

import imp
try:
    imp.find_module('eggs')
    found = True
except ImportError:
    found = False

To find dotted imports, you need to do more:

import imp
try:
    spam_info = imp.find_module('spam')
    spam = imp.load_module('spam', *spam_info)
    imp.find_module('eggs', spam.__path__) # __path__ is already a list
    found = True
except ImportError:
    found = False

You can also use pkgutil.find_loader (more or less the same as the python3 part

import pkgutil
eggs_loader = pkgutil.find_loader('eggs')
found = eggs_loader is not None

Python3

Python3 = 3.3

You should use importlib, How I went about doing this was:

import importlib
spam_loader = importlib.find_loader('spam')
found = spam_loader is not None

My expectation being, if you can find a loader for it, then it exists. You can also be a bit more smart about it, like filtering out what loaders you will accept. For example:

import importlib
spam_loader = importlib.find_loader('spam')
# only accept it as valid if there is a source file for the module - no bytecode only.
found = issubclass(type(spam_loader), importlib.machinery.SourceFileLoader)

Python3 = 3.4

In Python3.4 importlib.find_loader python docs was deprecated in favour of importlib.util.find_spec. The recommended method is the importlib.util.find_spec. There are others like importlib.machinery.FileFinder, which is useful if you're after a specific file to load. Figuring out how to use them is beyond the scope of this.

import importlib
spam_spec = importlib.util.find_spec("spam")
found = spam_spec is not None

This also works with relative imports but you must supply the starting package, so you could also do:

import importlib
spam_spec = importlib.util.find_spec("..spam", package="eggs.bar")
found = spam_spec is not None
spam_spec.name == "eggs.spam"

While I'm sure there exists a reason for doing this - I'm not sure what it would be.

WARNING

When trying to find a submodule, it will import the parent module (for all of the above methods)!

food/
  |- __init__.py
  |- eggs.py

## __init__.py
print("module food loaded")

## eggs.py
print("module eggs")

were you then to run
>>> import importlib
>>> spam_spec = importlib.find_spec("food.eggs")
module food loaded
ModuleSpec(name='food.eggs', loader=<_frozen_importlib.SourceFileLoader object at 0x10221df28>, origin='/home/user/food/eggs.py')

comments welcome on getting around this

Acknowledgements

  • @rvighne for importlib
  • @lucas-guido for python3.3+ depricating find_loader
  • @enpenax for pkgutils.find_loader behaviour in python2.7

Is there a way to check if a file is in use?

Here is some code that as far as I can best tell does the same thing as the accepted answer but with less code:

    public static bool IsFileLocked(string file)
    {
        try
        {
            using (var stream = File.OpenRead(file))
                return false;
        }
        catch (IOException)
        {
            return true;
        }        
    }

However I think it is more robust to do it in the following manner:

    public static void TryToDoWithFileStream(string file, Action<FileStream> action, 
        int count, int msecTimeOut)
    {
        FileStream stream = null;
        for (var i = 0; i < count; ++i)
        {
            try
            {
                stream = File.OpenRead(file);
                break;
            }
            catch (IOException)
            {
                Thread.Sleep(msecTimeOut);
            }
        }
        action(stream);
    }

Opening database file from within SQLite command-line shell

Older SQLite command-line shells (sqlite3.exe) do not appear to offer the .open command or any readily identifiable alternative.

Although I found no definitive reference it seems that the .open command was introduced around version 3.15. The SQLite Release History first mentions the .open command with 2016-10-14 (3.15.0).

Sending command line arguments to npm script

You asked to be able to run something like npm start 8080. This is possible without needing to modify script.js or configuration files as follows.

For example, in your "scripts" JSON value, include--

"start": "node ./script.js server $PORT"

And then from the command-line:

$ PORT=8080 npm start

I have confirmed that this works using bash and npm 1.4.23. Note that this work-around does not require GitHub npm issue #3494 to be resolved.

Selecting data frame rows based on partial string match in a column

Try str_detect() from the stringr package, which detects the presence or absence of a pattern in a string.

Here is an approach that also incorporates the %>% pipe and filter() from the dplyr package:

library(stringr)
library(dplyr)

CO2 %>%
  filter(str_detect(Treatment, "non"))

   Plant        Type  Treatment conc uptake
1    Qn1      Quebec nonchilled   95   16.0
2    Qn1      Quebec nonchilled  175   30.4
3    Qn1      Quebec nonchilled  250   34.8
4    Qn1      Quebec nonchilled  350   37.2
5    Qn1      Quebec nonchilled  500   35.3
...

This filters the sample CO2 data set (that comes with R) for rows where the Treatment variable contains the substring "non". You can adjust whether str_detect finds fixed matches or uses a regex - see the documentation for the stringr package.

Disable scrolling when touch moving certain element

To my surprise, the "preventDefault()" method is working for me on latest Google Chrome (version 85) on iOS 13.7. It also works on Safari on the same device and also working on my Android 8.0 tablet. I am currently implemented it for 2D view on my site here: https://papercraft-maker.com

How to debug a GLSL shader?

You can't easily communicate back to the CPU from within GLSL. Using glslDevil or other tools is your best bet.

A printf would require trying to get back to the CPU from the GPU running the GLSL code. Instead, you can try pushing ahead to the display. Instead of trying to output text, output something visually distinctive to the screen. For example you can paint something a specific color only if you reach the point of your code where you want add a printf. If you need to printf a value you can set the color according to that value.

How to Use Order By for Multiple Columns in Laravel 4?

Here's another dodge that I came up with for my base repository class where I needed to order by an arbitrary number of columns:

public function findAll(array $where = [], array $with = [], array $orderBy = [], int $limit = 10)
{
    $result = $this->model->with($with);
    $dataSet = $result->where($where)
        // Conditionally use $orderBy if not empty
        ->when(!empty($orderBy), function ($query) use ($orderBy) {
            // Break $orderBy into pairs
            $pairs = array_chunk($orderBy, 2);
            // Iterate over the pairs
            foreach ($pairs as $pair) {
                // Use the 'splat' to turn the pair into two arguments
                $query->orderBy(...$pair);
            }
        })
        ->paginate($limit)
        ->appends(Input::except('page'));

    return $dataSet;
}

Now, you can make your call like this:

$allUsers = $userRepository->findAll([], [], ['name', 'DESC', 'email', 'ASC'], 100);

Python group by

Do it in 2 steps. First, create a dictionary.

>>> input = [('11013331', 'KAT'), ('9085267', 'NOT'), ('5238761', 'ETH'), ('5349618', 'ETH'), ('11788544', 'NOT'), ('962142', 'ETH'), ('7795297', 'ETH'), ('7341464', 'ETH'), ('9843236', 'KAT'), ('5594916', 'ETH'), ('1550003', 'ETH')]
>>> from collections import defaultdict
>>> res = defaultdict(list)
>>> for v, k in input: res[k].append(v)
...

Then, convert that dictionary into the expected format.

>>> [{'type':k, 'items':v} for k,v in res.items()]
[{'items': ['9085267', '11788544'], 'type': 'NOT'}, {'items': ['5238761', '5349618', '962142', '7795297', '7341464', '5594916', '1550003'], 'type': 'ETH'}, {'items': ['11013331', '9843236'], 'type': 'KAT'}]

It is also possible with itertools.groupby but it requires the input to be sorted first.

>>> sorted_input = sorted(input, key=itemgetter(1))
>>> groups = groupby(sorted_input, key=itemgetter(1))
>>> [{'type':k, 'items':[x[0] for x in v]} for k, v in groups]
[{'items': ['5238761', '5349618', '962142', '7795297', '7341464', '5594916', '1550003'], 'type': 'ETH'}, {'items': ['11013331', '9843236'], 'type': 'KAT'}, {'items': ['9085267', '11788544'], 'type': 'NOT'}]

Note both of these do not respect the original order of the keys. You need an OrderedDict if you need to keep the order.

>>> from collections import OrderedDict
>>> res = OrderedDict()
>>> for v, k in input:
...   if k in res: res[k].append(v)
...   else: res[k] = [v]
... 
>>> [{'type':k, 'items':v} for k,v in res.items()]
[{'items': ['11013331', '9843236'], 'type': 'KAT'}, {'items': ['9085267', '11788544'], 'type': 'NOT'}, {'items': ['5238761', '5349618', '962142', '7795297', '7341464', '5594916', '1550003'], 'type': 'ETH'}]

Keep only date part when using pandas.to_datetime

This is a simple way to extract the date:

import pandas as pd

d='2015-01-08 22:44:09' 
date=pd.to_datetime(d).date()
print(date)

getCurrentPosition() and watchPosition() are deprecated on insecure origins

You can run chrome with the --unsafely-treat-insecure-origin-as-secure="http://example.com" flag (replacing "example.com" with the origin you actually want to test), which will treat that origin as secure for this session. Note that you also need to include the --user-data-dir=/test/only/profile/dir to create a fresh testing profile for the flag to work.

For example if use Windows, Click Start and run.

chrome --unsafely-treat-insecure-origin-as-secure="http://localhost:8100"  --user-data-dir=C:\testprofile

How to terminate the script in JavaScript?

If you're looking for a way to forcibly terminate execution of all Javascript on a page, I'm not sure there is an officially sanctioned way to do that - it seems like the kind of thing that might be a security risk (although to be honest, I can't think of how it would be off the top of my head). Normally in Javascript when you want your code to stop running, you just return from whatever function is executing. (The return statement is optional if it's the last thing in the function and the function shouldn't return a value) If there's some reason returning isn't good enough for you, you should probably edit more detail into the question as to why you think you need it and perhaps someone can offer an alternate solution.

Note that in practice, most browsers' Javascript interpreters will simply stop running the current script if they encounter an error. So you can do something like accessing an attribute of an unset variable:

function exit() {
    p.blah();
}

and it will probably abort the script. But you shouldn't count on that because it's not at all standard, and it really seems like a terrible practice.

EDIT: OK, maybe this wasn't such a good answer in light of Ólafur's. Although the die() function he linked to basically implements my second paragraph, i.e. it just throws an error.

Configuring diff tool with .gitconfig

Refer to Microsoft vscode-tips-and-tricks. Just run these commands in your terminal:

git config --global merge.tool code

But firstly you need add code command to your PATH. enter image description here

How to format a duration in java? (e.g format H:MM:SS)

If you don't want to drag in libraries, it's simple enough to do yourself using a Formatter, or related shortcut eg. given integer number of seconds s:

  String.format("%d:%02d:%02d", s / 3600, (s % 3600) / 60, (s % 60));

Combine multiple results in a subquery into a single comma-separated value

You may need to provide some more details for a more precise response.

Since your dataset seems kind of narrow, you might consider just using a row per result and performing the post-processing at the client.

So if you are really looking to make the server do the work return a result set like

ID       Name       SomeColumn
1        ABC        X
1        ABC        Y
1        ABC        Z
2        MNO        R
2        MNO        S

which of course is a simple INNER JOIN on ID

Once you have the resultset back at the client, maintain a variable called CurrentName and use that as a trigger when to stop collecting SomeColumn into the useful thing you want it to do.

Case Statement Equivalent in R

If you got factor then you could change levels by standard method:

df <- data.frame(name = c('cow','pig','eagle','pigeon'), 
             stringsAsFactors = FALSE)
df$type <- factor(df$name) # First step: copy vector and make it factor
# Change levels:
levels(df$type) <- list(
    animal = c("cow", "pig"),
    bird = c("eagle", "pigeon")
)
df
#     name   type
# 1    cow animal
# 2    pig animal
# 3  eagle   bird
# 4 pigeon   bird

You could write simple function as a wrapper:

changelevels <- function(f, ...) {
    f <- as.factor(f)
    levels(f) <- list(...)
    f
}

df <- data.frame(name = c('cow','pig','eagle','pigeon'), 
                 stringsAsFactors = TRUE)

df$type <- changelevels(df$name, animal=c("cow", "pig"), bird=c("eagle", "pigeon"))

Going to a specific line number using Less in Unix

You can use sed for this too -

sed -n '320123'p filename 

This will print line number 320123.

If you want a range then you can do -

sed -n '320123,320150'p filename 

If you want from a particular line to the very end then -

sed -n '320123,$'p filename 

VBScript - How to make program wait until process has finished?

Probably something like this? (UNTESTED)

Sub Sample()
    Dim strWB4, strMyMacro
    strMyMacro = "Sheet1.my_macro_name"

    '
    '~~> Rest of Code
    '

    'loop through the folder and get the file names
    For Each Fil In FLD.Files
        Set x4WB = x1.Workbooks.Open(Fil)
        x4WB.Application.Visible = True

        x1.Run strMyMacro

        x4WB.Close

        Do Until IsWorkBookOpen(Fil) = False
            DoEvents
        Loop
    Next

    '
    '~~> Rest of Code
    '
End Sub

'~~> Function to check if the file is open
Function IsWorkBookOpen(FileName As String)
    Dim ff As Long, ErrNo As Long

    On Error Resume Next
    ff = FreeFile()
    Open FileName For Input Lock Read As #ff
    Close ff
    ErrNo = Err
    On Error GoTo 0

    Select Case ErrNo
    Case 0:    IsWorkBookOpen = False
    Case 70:   IsWorkBookOpen = True
    Case Else: Error ErrNo
    End Select
End Function

How should I unit test multithreaded code?

I just recently discovered (for Java) a tool called Threadsafe. It is a static analysis tool much like findbugs but specifically to spot multi-threading issues. It is not a replacement for testing but I can recommend it as part of writing reliable multi-threaded Java.

It even catches some very subtle potential issues around things like class subsumption, accessing unsafe objects through concurrent classes and spotting missing volatile modifiers when using the double checked locking paradigm.

If you write multithreaded Java give it a shot.

How to change environment's font size?

(VS Code 1.33.1 on Windows 7)

Zoom all (UI and editor): CTRL + +, CTRL + -.

Zoom editor: CTRL + Mouse Wheel.

See below how i fixed it.

As suggested by @Edwin: Pressing Control+Shift+P and then typing "settings" will allow you to easily find the user or workspace settings file.

My settings file is found here: "C:\Users\You_user\AppData\Roaming\Code\User\settings.json"

My file looks like this:

{
    "editor.fontSize": 12,
    "editor.suggestFontSize": 6,
    "markdown.preview.fontSize": 0,
    "terminal.integrated.fontSize": 10,
    "window.zoomLevel": 0,
    "workbench.sideBar.location": "left",
    "editor.mouseWheelZoom": true
}

Dynamic function name in javascript?

I might be missing the obvious here, but what's wrong with just adding the name? functions are invoked regardless of their name. names are just used for scoping reasons. if you assign it to a variable, and it's in scope, it can be called. hat happens is your are executing a variable which happens to be a function. if you must have a name for identification reasons when debugging, insert it between the keyword function and the opening brace.

_x000D_
_x000D_
var namedFunction = function namedFunction (a,b) {return a+b};_x000D_
_x000D_
alert(namedFunction(1,2));_x000D_
alert(namedFunction.name);_x000D_
alert(namedFunction.toString());
_x000D_
_x000D_
_x000D_

an alternative approach is to wrap the function in an outer renamed shim, which you can also pass into an outer wrapper, if you don't want to dirty the surrounding namespace. if you are wanting to actually dynamically create the function from strings (which most of these examples do), it's trivial to rename the source to do what you want. if however you want to rename existing functions without affecting their functionality when called elsewhere, a shim is the only way to achieve it.

_x000D_
_x000D_
(function(renamedFunction) {_x000D_
_x000D_
  alert(renamedFunction(1,2));_x000D_
  alert(renamedFunction.name);_x000D_
  alert(renamedFunction.toString());_x000D_
  alert(renamedFunction.apply(this,[1,2]));_x000D_
_x000D_
_x000D_
})(function renamedFunction(){return namedFunction.apply(this,arguments);});_x000D_
_x000D_
function namedFunction(a,b){return a+b};
_x000D_
_x000D_
_x000D_

How to get an Instagram Access Token

By using https://www.hurl.it/ i was able to see this: { "code": 400, "error_type": "OAuthException", "error_message": "Matching code was not found or was already used." }

so: you have to get new code for every request.

MS Access VBA: Sending an email through Outlook

Here is email code I used in one of my databases. I just made variables for the person I wanted to send it to, CC, subject, and the body. Then you just use the DoCmd.SendObject command. I also set it to "True" after the body so you can edit the message before it automatically sends.

Public Function SendEmail2()

Dim varName As Variant          
Dim varCC As Variant            
Dim varSubject As Variant      
Dim varBody As Variant          

varName = "[email protected]"
varCC = "[email protected], [email protected]"
'separate each email by a ','

varSubject = "Hello"
'Email subject

varBody = "Let's get ice cream this week"

'Body of the email
DoCmd.SendObject , , , varName, varCC, , varSubject, varBody, True, False
'Send email command. The True after "varBody" allows user to edit email before sending.
'The False at the end will not send it as a Template File

End Function

Multiple "order by" in LINQ

This should work for you:

var movies = _db.Movies.OrderBy(c => c.Category).ThenBy(n => n.Name)

Why do you need ./ (dot-slash) before executable or script name to run it in bash?

Because on Unix, usually, the current directory is not in $PATH.

When you type a command the shell looks up a list of directories, as specified by the PATH variable. The current directory is not in that list.

The reason for not having the current directory on that list is security.

Let's say you're root and go into another user's directory and type sl instead of ls. If the current directory is in PATH, the shell will try to execute the sl program in that directory (since there is no other sl program). That sl program might be malicious.

It works with ./ because POSIX specifies that a command name that contain a / will be used as a filename directly, suppressing a search in $PATH. You could have used full path for the exact same effect, but ./ is shorter and easier to write.

EDIT

That sl part was just an example. The directories in PATH are searched sequentially and when a match is made that program is executed. So, depending on how PATH looks, typing a normal command may or may not be enough to run the program in the current directory.

What is the difference between response.sendRedirect() and request.getRequestDispatcher().forward(request,response)

1.redirect return the request to the browser from server,then resend the request to the server from browser.

2.forward send the request to another servlet (servlet to servlet).

Bootstrap 3 - 100% height of custom div inside column

You need to set the height of every parent element of the one you want the height defined.

<html style="height: 100%;">
  <body style="height: 100%;">
    <div style="height: 100%;">
      <p>
        Make this division 100% height.
      </p>
    </div>
  </body>
</html>

Article.

JsFiddle example

How do you clear a stringstream variable?

This should be the most reliable way regardless of the compiler:

m=std::stringstream();

Delete all data in SQL Server database

I'm aware this is late, but I agree with AlexKuznetsov's suggestion to script the database, rather than going through the hassle of purging the data from the tables. If the TRUNCATE solution will not work, and you happen to have a large amount of data, issuing (logged) DELETE statements might take a long time, and you'll be left with identifiers that have not been reseeded (i.e. an INSERT statement into a table with an IDENTITY column would get you an ID of 50000 instead of an ID of 1).

To script a whole database, in SSMS, right-click the database, then select TASKS -> Generate scripts:

enter image description here

Click Next to skip the Wizard opening screen, and then select which objects you want to script:

enter image description here

In the Set scripting options screen, you can pick settings for the scripting, like whether to generate 1 script for all the objects, or separate scripts for the individual objects, and whether to save the file in Unicode or ANSI:

enter image description here

The wizard will show a summary, which you can use to verify everything is as desired, and close by clicking on 'Finish'.

Change Color of Fonts in DIV (CSS)

To do links, you can do

.social h2 a:link {
  color: pink;
  font-size: 14px;   
}

You can change the hover, visited, and active link styling too. Just replace "link" with what you want to style. You can learn more at the w3schools page CSS Links.

How to asynchronously call a method in Java

i don't like the idea of using Reflection for that.
Not only dangerous for missing it in some refactoring, but it can also be denied by SecurityManager.

FutureTask is a good option as the other options from the java.util.concurrent package.
My favorite for simple tasks:

    Executors.newSingleThreadExecutor().submit(task);

little bit shorter than creating a Thread (task is a Callable or a Runnable)

How to convert C++ Code to C

There is indeed such a tool, Comeau's C++ compiler. . It will generate C code which you can't manually maintain, but that's no problem. You'll maintain the C++ code, and just convert to C on the fly.

How to solve time out in phpmyadmin?

I had the same issue and I used command line in order to import the SQL file. This method has 3 advantages:

  1. It is a very easy way by running only 1 command line
  2. It runs way faster
  3. It does not have limitation

If you want to do this just follow this 3 steps:

  1. Navigate to this path (i use wamp):

    C:\wamp\bin\mysql\mysql5.6.17\bin>

  2. Copy your sql file inside this path (ex file.sql)

  3. Run this command:

    mysql -u username -p database_name < file.sql

Note: if you already have your msql enviroment variable path set, you don't need to move your file.sql in the bin directory and you should only navigate to the path of the file.

Change onClick attribute with javascript

Well, just do this and your problem is solved :

document.getElementById('buttonLED'+id).setAttribute('onclick','writeLED(1,1)')

Have a nice day XD

How to drop all tables in a SQL Server database?

Short and sweet:

USE YOUR_DATABASE_NAME
-- Disable all referential integrity constraints
EXEC sp_MSforeachtable 'ALTER TABLE ? NOCHECK CONSTRAINT ALL'
GO

-- Drop all PKs and FKs
declare @sql nvarchar(max)
SELECT @sql = STUFF((SELECT '; ' + 'ALTER TABLE ' + Table_Name  +'  drop constraint ' + Constraint_Name  from Information_Schema.CONSTRAINT_TABLE_USAGE ORDER BY Constraint_Name FOR XML PATH('')),1,1,'')
EXECUTE (@sql)
GO

-- Drop all tables
EXEC sp_MSforeachtable 'DROP TABLE ?'
GO

How to align checkboxes and their labels consistently cross-browsers

Hardcode the checkbox's height and width, remove its padding, and make its height plus vertical margins equal to the label's line-height. If the label text is inline, float the checkbox. Firefox, Chrome, and IE7+ all render the following example identically: http://www.kornea.com/css-checkbox-align

How do I get the SharedPreferences from a PreferenceActivity in Android?

import android.preference.PreferenceManager;
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
// then you use
prefs.getBoolean("keystring", true);

Update

According to Shared Preferences | Android Developer Tutorial (Part 13) by Sai Geetha M N,

Many applications may provide a way to capture user preferences on the settings of a specific application or an activity. For supporting this, Android provides a simple set of APIs.

Preferences are typically name value pairs. They can be stored as “Shared Preferences” across various activities in an application (note currently it cannot be shared across processes). Or it can be something that needs to be stored specific to an activity.

  1. Shared Preferences: The shared preferences can be used by all the components (activities, services etc) of the applications.

  2. Activity handled preferences: These preferences can only be used within the particular activity and can not be used by other components of the application.

Shared Preferences:

The shared preferences are managed with the help of getSharedPreferences method of the Context class. The preferences are stored in a default file (1) or you can specify a file name (2) to be used to refer to the preferences.

(1) The recommended way is to use by the default mode, without specifying the file name

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);

(2) Here is how you get the instance when you specify the file name

public static final String PREF_FILE_NAME = "PrefFile";
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);

MODE_PRIVATE is the operating mode for the preferences. It is the default mode and means the created file will be accessed by only the calling application. Other two modes supported are MODE_WORLD_READABLE and MODE_WORLD_WRITEABLE. In MODE_WORLD_READABLE other application can read the created file but can not modify it. In case of MODE_WORLD_WRITEABLE other applications also have write permissions for the created file.

Finally, once you have the preferences instance, here is how you can retrieve the stored values from the preferences:

int storedPreference = preferences.getInt("storedInt", 0);

To store values in the preference file SharedPreference.Editor object has to be used. Editor is a nested interface in the SharedPreference class.

SharedPreferences.Editor editor = preferences.edit();
editor.putInt("storedInt", storedPreference); // value to store
editor.commit();

Editor also supports methods like remove() and clear() to delete the preference values from the file.

Activity Preferences:

The shared preferences can be used by other application components. But if you do not need to share the preferences with other components and want to have activity private preferences you can do that with the help of getPreferences() method of the activity. The getPreference method uses the getSharedPreferences() method with the name of the activity class for the preference file name.

Following is the code to get preferences

SharedPreferences preferences = getPreferences(MODE_PRIVATE);
int storedPreference = preferences.getInt("storedInt", 0);

The code to store values is also the same as in case of shared preferences.

SharedPreferences preferences = getPreference(MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putInt("storedInt", storedPreference); // value to store
editor.commit();

You can also use other methods like storing the activity state in database. Note Android also contains a package called android.preference. The package defines classes to implement application preferences UI.

To see some more examples check Android's Data Storage post on developers site.

Assigning strings to arrays of characters

There is no such thing as a "string" in C. In C, strings are one-dimensional array of char, terminated by a null character \0. Since you can't assign arrays in C, you can't assign strings either. The literal "hello" is syntactic sugar for const char x[] = {'h','e','l','l','o','\0'};

The correct way would be:

char s[100];
strncpy(s, "hello", 100);

or better yet:

#define STRMAX 100
char    s[STRMAX];
size_t  len;
len = strncpy(s, "hello", STRMAX);

How do I make text bold in HTML?

HTML doesn't have a <bold> tag, instead you would have to use <b>. Note however, that using <b> is discouraged in favor of CSS for a while now. You would be better off using CSS to achieve that.

The <strong> tag is a semantic element for strong emphasis which defaults to bold.

How do you use bcrypt for hashing passwords in PHP?


Edit: 2013.01.15 - If your server will support it, use martinstoeckli's solution instead.


Everyone wants to make this more complicated than it is. The crypt() function does most of the work.

function blowfishCrypt($password,$cost)
{
    $chars='./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    $salt=sprintf('$2y$%02d$',$cost);
//For PHP < PHP 5.3.7 use this instead
//    $salt=sprintf('$2a$%02d$',$cost);
    //Create a 22 character salt -edit- 2013.01.15 - replaced rand with mt_rand
    mt_srand();
    for($i=0;$i<22;$i++) $salt.=$chars[mt_rand(0,63)];
    return crypt($password,$salt);
}

Example:

$hash=blowfishCrypt('password',10); //This creates the hash
$hash=blowfishCrypt('password',12); //This creates a more secure hash
if(crypt('password',$hash)==$hash){ /*ok*/ } //This checks a password

I know it should be obvious, but please don't use 'password' as your password.

How do I catch a numpy warning like it's an exception (not just for testing)?

Remove warnings.filterwarnings and add:

numpy.seterr(all='raise')

No submodule mapping found in .gitmodule for a path that's not a submodule

I resolved this issue for me. Initially I tried to do this:

git submodule add --branch master [URL] [PATH_TO_SUBMODULE]

As it turns out the specification of the --branch option should not be used if you want to clone the master branch. It throws this error:

fatal: Cannot force update the current branch.
Unable to checkout submodule '[PATH_TO_SUBMODULE]'

Every time you try to do a

git submodule sync

This error will be thrown:

No submodule mapping found in .gitmodules for path '[PATH_TO_SUBMODULE]'

And the lines needed in .gitmodules are never added.

So the solution for me was this:

git submodule add [URL] [PATH_TO_SUBMODULE]

How to return the output of stored procedure into a variable in sql server

With the Return statement from the proc, I needed to assign the temp variable and pass it to another stored procedure. The value was getting assigned fine but when passing it as a parameter, it lost the value. I had to create a temp table and set the variable from the table (SQL 2008)

From this: 
declare @anID int
exec @anID = dbo.StoredProc_Fetch @ID, @anotherID, @finalID
exec dbo.ADifferentStoredProc @anID (no value here)

To this:
declare @t table(id int) 
declare @anID int
insert into @t exec dbo.StoredProc_Fetch @ID, @anotherID, @finalID
set @anID= (select Top 1 * from @t)

How can I get dict from sqlite query?

import sqlite3

db = sqlite3.connect('mydatabase.db')
cursor = db.execute('SELECT * FROM students ORDER BY CREATE_AT')
studentList = cursor.fetchall()

columnNames = list(map(lambda x: x[0], cursor.description)) #students table column names list
studentsAssoc = {} #Assoc format is dictionary similarly


#THIS IS ASSOC PROCESS
for lineNumber, student in enumerate(studentList):
    studentsAssoc[lineNumber] = {}

    for columnNumber, value in enumerate(student):
        studentsAssoc[lineNumber][columnNames[columnNumber]] = value


print(studentsAssoc)

The result is definitely true, but I do not know the best.

Convert INT to VARCHAR SQL

SELECT cast(CAST([field_name] AS bigint) as nvarchar(255)) FROM table_name

How to run a PowerShell script

I have a very simple answer which works:

  1. Open PowerShell in administrator mode
  2. Run: set-executionpolicy unrestricted
  3. Open a regular PowerShell window and run your script.

I found this solution following the link that was given as part of error message: About Execution Policies

How to sort a list of lists by a specific index of the inner list?

Like this:

import operator
l = [...]
sorted_list = sorted(l, key=operator.itemgetter(desired_item_index))

Pythonic way to return list of every nth item in a larger list

  1. source_list[::10] is the most obvious, but this doesn't work for any iterable and is not memory efficient for large lists.
  2. itertools.islice(source_sequence, 0, None, 10) works for any iterable and is memory-efficient, but probably is not the fastest solution for large list and big step.
  3. (source_list[i] for i in xrange(0, len(source_list), 10))

Change Select List Option background colour on hover in html

No, it's not possible.

It's really, if not use native selects, if you create custom select widget from html elements, t.e. "li".

Convert java.util.date default format to Timestamp in Java

You can use DateFormat(java.text.*) to parse the date:

DateFormat df = new SimpleDateFormat("EEE MMM dd kk:mm:ss z yyyy", Locale.ENGLISH);
Date d = df.parse("Mon May 27 11:46:15 IST 2013")

You will have to change the locale to match your own (with this you will get 10:46:15). Then you can use the same code you have to convert it to a timestamp.

How to calculate Average Waiting Time and average Turn-around time in SJF Scheduling?

Gantt chart is wrong... First process P3 has arrived so it will execute first. Since the burst time of P3 is 3sec after the completion of P3, processes P2,P4, and P5 has been arrived. Among P2,P4, and P5 the shortest burst time is 1sec for P2, so P2 will execute next. Then P4 and P5. At last P1 will be executed.

Gantt chart for this ques will be:

| P3 | P2 | P4 | P5 | P1 |

1    4    5    7   11   14

Average waiting time=(0+2+2+3+3)/5=2

Average Turnaround time=(3+3+4+7+6)/5=4.6

Check if a path represents a file or a folder

There is no way for the system to tell you if a String represent a file or directory, if it does not exist in the file system. For example:

Path path = Paths.get("/some/path/to/dir");
System.out.println(Files.isDirectory(path)); // return false
System.out.println(Files.isRegularFile(path)); // return false

And for the following example:

Path path = Paths.get("/some/path/to/dir/file.txt");
System.out.println(Files.isDirectory(path));  //return false
System.out.println(Files.isRegularFile(path));  // return false

So we see that in both case system return false. This is true for both java.io.File and java.nio.file.Path

MySQL Delete all rows from table and reset ID to zero

If you cannot use TRUNCATE (e.g. because of foreign key constraints) you can use an alter table after deleting all rows to restart the auto_increment:

ALTER TABLE mytable AUTO_INCREMENT = 1

Python dictionary get multiple values

If the fallback keys are not too many you can do something like this

value = my_dict.get('first_key') or my_dict.get('second_key')

The model backing the 'ApplicationDbContext' context has changed since the database was created

I was having same problem as a7madx7, but with stable release of EF (v6.1.1), and found resolution posted in:

http://cybarlab.com/context-has-changed-since-the-database-was-created

with variation in: http://patrickdesjardins.com/blog/the-model-backing-the-context-has-changed-since-the-database-was-created-ef4-3

2nd link includes specific mention for VB..... "you can simply add all the databasecontext that are having this problem on your app_start method in the global.asax file like this":

Database.SetInitializer(Of DatabaseContext)(Nothing)

NB: i had to replace "DatabaseContext" with the name of my class implementing DbContext

Update: Also, when using codefirst approach to connect to existing tables, check database to see if EF has created a table "_migrationhistory" to store mappings. I re-named this table then was able to remove SetInitializer from global.asax.

C# Numeric Only TextBox Control

this way is right with me:

private void textboxNumberic_KeyPress(object sender, KeyPressEventArgs e)
{
     const char Delete = (char)8;
     e.Handled = !Char.IsDigit(e.KeyChar) && e.KeyChar != Delete;
}

assign value using linq

It can be done this way as well

foreach (Company company in listofCompany.Where(d => d.Id = 1)).ToList())
                {
                    //do your stuff here
                    company.Id= 2;
                    company.Name= "Sample"
                }

Java Error: illegal start of expression

Declare

public static int[] locations={1,2,3};

outside of the main method.

MySQL - Cannot add or update a child row: a foreign key constraint fails

I had faced same issue while creating foreign constraints on table. the simple way of coming out of this issue are first take backup of your parent and child table then truncate child table and again try to make a relation. hope this will solve the problem.

Protractor : How to wait for page complete after click a button?

Depending on what you want to do, you can try:

browser.waitForAngular();

or

btnLoginEl.click().then(function() {
  // do some stuff 
}); 

to solve the promise. It would be better if you can do that in the beforeEach.

NB: I noticed that the expect() waits for the promise inside (i.e. getCurrentUrl) to be solved before comparing.

How to cherry-pick from a remote branch?

Since "zebra" is a remote branch, I was thinking I don't have its data locally.

You are correct that you don't have the right data, but tried to resolve it in the wrong way. To collect data locally from a remote source, you need to use git fetch. When you did git checkout zebra you switched to whatever the state of that branch was the last time you fetched. So fetch from the remote first:

# fetch just the one remote
git fetch <remote>
# or fetch from all remotes
git fetch --all
# make sure you're back on the branch you want to cherry-pick to
git cherry-pick xyz

What are the most useful Intellij IDEA keyboard shortcuts?

Try using the Key Promoter plugin. That will help in learning the shortcuts. Couple of shortcuts apart from the above suggestions:

  • Alt + Ins: Works consistently to insert anything. (Add a new class, method etc)
  • Ctrl + Alt + T: Surround code block. Another useful stuff.

Difference between exit() and sys.exit() in Python

exit is a helper for the interactive shell - sys.exit is intended for use in programs.

The site module (which is imported automatically during startup, except if the -S command-line option is given) adds several constants to the built-in namespace (e.g. exit). They are useful for the interactive interpreter shell and should not be used in programs.


Technically, they do mostly the same: raising SystemExit. sys.exit does so in sysmodule.c:

static PyObject *
sys_exit(PyObject *self, PyObject *args)
{
    PyObject *exit_code = 0;
    if (!PyArg_UnpackTuple(args, "exit", 0, 1, &exit_code))
        return NULL;
    /* Raise SystemExit so callers may catch it or clean up. */
    PyErr_SetObject(PyExc_SystemExit, exit_code);
   return NULL;
}

While exit is defined in site.py and _sitebuiltins.py, respectively.

class Quitter(object):
    def __init__(self, name):
        self.name = name
    def __repr__(self):
        return 'Use %s() or %s to exit' % (self.name, eof)
    def __call__(self, code=None):
        # Shells like IDLE catch the SystemExit, but listen when their
        # stdin wrapper is closed.
        try:
            sys.stdin.close()
        except:
            pass
        raise SystemExit(code)
__builtin__.quit = Quitter('quit')
__builtin__.exit = Quitter('exit')

Note that there is a third exit option, namely os._exit, which exits without calling cleanup handlers, flushing stdio buffers, etc. (and which should normally only be used in the child process after a fork()).

how to set default culture info for entire c# application

With 4.0, you will need to manage this yourself by setting the culture for each thread as Alexei describes. But with 4.5, you can define a culture for the appdomain and that is the preferred way to handle this. The relevant apis are CultureInfo.DefaultThreadCurrentCulture and CultureInfo.DefaultThreadCurrentUICulture.

How to set width of mat-table column in angular?

If you're using scss for your styles you can use a mixin to help generate the code. Your styles will quickly get out of hand if you put all the properties every time.

This is a very simple example - really nothing more than a proof of concept, you can extend this with multiple properties and rules as needed.

@mixin mat-table-columns($columns)
{
    .mat-column-
    {
        @each $colName, $props in $columns {

            $width: map-get($props, 'width');

            &#{$colName} 
            {
                flex: $width;
                min-width: $width;

                @if map-has-key($props, 'color') 
                {
                    color: map-get($props, 'color');
                }
            }  
        }
    }
}

Then in your component where your table is defined you just do this:

@include mat-table-columns((

    orderid: (width: 6rem, color: gray),
    date: (width: 9rem),
    items: (width: 20rem)

));

This generates something like this:

.mat-column-orderid[_ngcontent-c15] {
  flex: 6rem;
  min-width: 6rem;
  color: gray; }

.mat-column-date[_ngcontent-c15] {
  flex: 9rem;
  min-width: 9rem; }

In this version width becomes flex: value; min-width: value.

For your specific example you could add wrap: true or something like that as a new parameter.

Making Enter key on an HTML form submit instead of activating button

$("form#submit input").on('keypress',function(event) {
  event.preventDefault();
  if (event.which === 13) {
    $('button.submit').trigger('click');
  }
});

remove all special characters in java

use [\\W+] or "[^a-zA-Z0-9]" as regex to match any special characters and also use String.replaceAll(regex, String) to replace the spl charecter with an empty string. remember as the first arg of String.replaceAll is a regex you have to escape it with a backslash to treat em as a literal charcter.

          String c= "hjdg$h&jk8^i0ssh6";
        Pattern pt = Pattern.compile("[^a-zA-Z0-9]");
        Matcher match= pt.matcher(c);
        while(match.find())
        {
            String s= match.group();
        c=c.replaceAll("\\"+s, "");
        }
        System.out.println(c);

Set left margin for a paragraph in html

<p style="margin-left:5em;">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut lacinia vestibulum quam sit amet aliquet. Phasellus tempor nisi eget tellus venenatis tempus. Aliquam dapibus porttitor convallis. Praesent pretium luctus orci, quis ullamcorper lacus lacinia a. Integer eget molestie purus. Vestibulum porta mollis tempus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. </p>

That'll do it, there's a few improvements obviously, but that's the basics. And I use 'em' as the measurement, you may want to use other units, like 'px'.

EDIT: What they're describing above is a way of associating groups of styles, or classes, with elements on a web page. You can implement that in a few ways, here's one which may suit you:

In your HTML page, containing the <p> tagged content from your DB add in a new 'style' node and wrap the styles you want to declare in a class like so:

<head>
  <style type="text/css">
    p { margin-left:5em; /* Or another measurement unit, like px */ }
  </style>
</head>
<body>
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut lacinia vestibulum quam sit amet aliquet.</p>
</body>

So above, all <p> elements in your document will have that style rule applied. Perhaps you are pumping your paragraph content into a container of some sort? Try this:

<head>
  <style type="text/css">
    .container p { margin-left:5em; /* Or another measurement unit, like px */ }
  </style>
</head>
<body>
  <div class="container">
    <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut lacinia vestibulum quam sit amet aliquet.</p>
  </div>
  <p>Vestibulum porta mollis tempus. Class aptent taciti sociosqu ad litora torquent per conubia nostra.</p>
</body>

In the example above, only the <p> element inside the div, whose class name is 'container', will have the styles applied - and not the <p> element outside the container.

In addition to the above, you can collect your styles together and remove the style element from the <head> tag, replacing it with a <link> tag, which points to an external CSS file. This external file is where you'd now put your <p> tag styles. This concept is known as 'seperating content from style' and is considered good practice, and is also an extendible way to create styles, and can help with low maintenance.

How do I include a newline character in a string in Delphi?

In the System.pas (which automatically gets used) the following is defined:

const
  sLineBreak = {$IFDEF LINUX} AnsiChar(#10) {$ENDIF} 
               {$IFDEF MSWINDOWS} AnsiString(#13#10) {$ENDIF};

This is from Delphi 2009 (notice the use of AnsiChar and AnsiString). (Line wrap added by me.)

So if you want to make your TLabel wrap, make sure AutoSize is set to true, and then use the following code:

label1.Caption := 'Line one'+sLineBreak+'Line two';

Works in all versions of Delphi since sLineBreak was introduced, which I believe was Delphi 6.

SQL Server: Attach incorrect version 661

SQL Server 2008 databases are version 655. SQL Server 2008 R2 databases are 661. You are trying to attach an 2008 R2 database (v. 661) to an 2008 instance and this is not supported. Once the database has been upgraded to an 2008 R2 version, it cannot be downgraded. You'll have to either upgrade your 2008 SP2 instance to R2, or you have to copy out the data in that database into an 2008 database (eg using the data migration wizard, or something equivalent).

The message is misleading, to say the least, it says 662 because SQL Server 2008 SP2 does support 662 as a database version, this is when 15000 partitions are enabled in the database, see Support for 15000 Partitions.docx. Enabling the support bumps the DB version to 662, disabling it moves it back to 655. But SQL Server 2008 SP2 does not support 661 (the R2 version).

PostgreSQL function for last inserted ID

Based on @ooZman 's answer above, this seems to work for PostgreSQL v12 when you need to INSERT with the next value of a "sequence" (akin to auto_increment) without goofing anything up in your table(s) counter(s). (Note: I haven't tested it in more complex DB cluster configurations though...)

Psuedo Code

$insert_next_id = $return_result->query(" select (setval('"your_id_seq"', (select nextval('"your_id_seq"')) - 1, true)) +1; ")

Get current NSDate in timestamp format

Can also use

@(time(nil)).stringValue);

for timestamp in seconds.

How to set Android camera orientation properly?

This solution will work for all versions of Android. You can use reflection in Java to make it work for all Android devices:

Basically you should create a reflection wrapper to call the Android 2.2 setDisplayOrientation, instead of calling the specific method.

The method:

    protected void setDisplayOrientation(Camera camera, int angle){
    Method downPolymorphic;
    try
    {
        downPolymorphic = camera.getClass().getMethod("setDisplayOrientation", new Class[] { int.class });
        if (downPolymorphic != null)
            downPolymorphic.invoke(camera, new Object[] { angle });
    }
    catch (Exception e1)
    {
    }
}

And instead of using camera.setDisplayOrientation(x) use setDisplayOrientation(camera, x) :

    if (Integer.parseInt(Build.VERSION.SDK) >= 8)
        setDisplayOrientation(mCamera, 90);
    else
    {
        if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT)
        {
            p.set("orientation", "portrait");
            p.set("rotation", 90);
        }
        if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE)
        {
            p.set("orientation", "landscape");
            p.set("rotation", 90);
        }
    }   

How to send SMS in Java

It depends on how you're going to work and who your provider is.

If you work with a sms-gateway company you'll probably work through SMPP protocol (3.4 is still the most common), then have a look on OpenSMPP and jSMPP. These are powerful libs to work with SMPP.

If you're going to work with your own hardware (f.e. a gsm-modem) the easiest way to send messages is through AT commands, they differ depends on the model, so, you should find out what AT commands is supported by your modem. Next, if your modem has an IP and open to connection, you can send commands through java socket

Socket smppSocket = new Socket("YOUR_MODEM_IP", YOUR_MODEM_PORT);
DataOutputStream os = new DataOutputStream(smppSocket.getOutputStream());
DataInputStream is = new DataInputStream(smppSocket.getInputStream());

os.write(some_byte_array[]);
is.readLine();

Otherwise you'll work through a COM port, but the method is the same (sending AT commands), you can find more information how to work with serial ports here.

How to find out client ID of component for ajax update/render? Cannot find component with expression "foo" referenced from "bar"

It's because the tab is a naming container aswell... your update should be update="Search:insTable:display" What you can do aswell is just place your dialog outside the form and still inside the tab then it would be: update="Search:display"

How to store a list in a column of a database table

you can store it as text that looks like a list and create a function that can return its data as an actual list. example:

database:

 _____________________
|  word  | letters    |
|   me   | '[m, e]'   |
|  you   |'[y, o, u]' |  note that the letters column is of type 'TEXT'
|  for   |'[f, o, r]' |
|___in___|_'[i, n]'___|

And the list compiler function (written in python, but it should be easily translatable to most other programming languages). TEXT represents the text loaded from the sql table. returns list of strings from string containing list. if you want it to return ints instead of strings, make mode equal to 'int'. Likewise with 'string', 'bool', or 'float'.

def string_to_list(string, mode):
    items = []
    item = ""
    itemExpected = True
    for char in string[1:]:
        if itemExpected and char not in [']', ',', '[']:
            item += char
        elif char in [',', '[', ']']:
            itemExpected = True
            items.append(item)
            item = ""
    newItems = []
    if mode == "int":
        for i in items:
            newItems.append(int(i))

    elif mode == "float":
        for i in items:
            newItems.append(float(i))

    elif mode == "boolean":
        for i in items:
            if i in ["true", "True"]:
                newItems.append(True)
            elif i in ["false", "False"]:
                newItems.append(False)
            else:
                newItems.append(None)
    elif mode == "string":
        return items
    else:
        raise Exception("the 'mode'/second parameter of string_to_list() must be one of: 'int', 'string', 'bool', or 'float'")
    return newItems

Also here is a list-to-string function in case you need it.

def list_to_string(lst):
    string = "["
    for i in lst:
        string += str(i) + ","
    if string[-1] == ',':
        string = string[:-1] + "]"
    else:
        string += "]"
    return string

Export to CSV using MVC, C# and jQuery

From a button in view call .click(call some java script). From there call controller method by window.location.href = 'Controller/Method';

In controller either do the database call and get the datatable or call some method get the data from database table to a datatable and then do following,

using (DataTable dt = new DataTable())
                        {
                            sda.Fill(dt);
                            //Build the CSV file data as a Comma separated string.
                            string csv = string.Empty;
                            foreach (DataColumn column in dt.Columns)
                            {
                                //Add the Header row for CSV file.
                                csv += column.ColumnName + ',';
                            }
                            //Add new line.
                            csv += "\r\n";
                            foreach (DataRow row in dt.Rows)
                            {
                                foreach (DataColumn column in dt.Columns)
                                {
                                    //Add the Data rows.
                                    csv += row[column.ColumnName].ToString().Replace(",", ";") + ',';
                                }
                                //Add new line.
                                csv += "\r\n";
                             }
                             //Download the CSV file.
                             Response.Clear();
                             Response.Buffer = true;
                             Response.AddHeader("content-disposition", "attachment;filename=SqlExport"+DateTime.Now+".csv");
                             Response.Charset = "";
                             //Response.ContentType = "application/text";
                             Response.ContentType = "application/x-msexcel";
                             Response.Output.Write(csv);
                             Response.Flush();
                             Response.End();
                           }

Python 3 - ValueError: not enough values to unpack (expected 3, got 2)

You probably want to assign the lastname you are reading out here

lastname = sheet.cell(row=r, column=3).value

to something; currently the program just forgets it

you could do that two lines after, like so

unpaidMembers[name] = lastname, email

your program will still crash at the same place, because .items() still won't give you 3-tuples but rather something that has this structure: (name, (lastname, email))

good news is, python can handle this

for name, (lastname, email) in unpaidMembers.items():

etc.

"Gradle Version 2.10 is required." Error

Download the latest gradle-3.0-all.zip from

http://gradle.org/gradle-download/

download from Complete Distribution link

open in android studio file ->settings ->gradle

open the path and paste the downloaded zip folder gradle-3.0 in that folder

change your gradle 2.8 to gradle 3.0 in file ->settings ->gradle

Or you can change your gradle wrapper in the project

edit YourProject\gradle\wrapper\gradle-wrapper.properties file and edit the field distributionUrl in to

distributionUrl= https://services.gradle.org/distributions/gradle-3.0-all.zip

Clear a terminal screen for real

Compile this app.

#include <iostream>
#include <cstring>

int main()
{
  char str[1000];
  memset(str, '\n', 999);
  str[999] = 0;
  std::cout << str << std::endl;
  return 0;
}

Undefined Reference to

I had this issue when I forgot to add the new .h/.c file I created to the meson recipe so this is just a friendly reminder.

Most efficient way to remove special characters from string

I would use a String Replace with a Regular Expression searching for "special characters", replacing all characters found with an empty string.

Use <Image> with a local file

From the UIExplorer sample app:

Static assets should be required by prefixing with image! and are located in the app bundle.

enter image description here

So like this:

render: function() {
  return (
    <View style={styles.horizontal}>
      <Image source={require('image!uie_thumb_normal')} style={styles.icon} />
      <Image source={require('image!uie_thumb_selected')} style={styles.icon} />
      <Image source={require('image!uie_comment_normal')} style={styles.icon} />
      <Image source={require('image!uie_comment_highlighted')} style={styles.icon} />
    </View>
  );
}

How to execute mongo commands through shell scripts?

Single shell script solution with ability to pass mongo arguments (--quiet, dbname, etc):

#!/usr/bin/env -S mongo --quiet localhost:27017/test

cur = db.myCollection.find({});
while(cur.hasNext()) {
  printjson(cur.next());
}

The -S flag might not work on all platforms.

How to get numeric value from a prompt box?

You can use parseInt() but, as mentioned, the radix (base) should be specified:

x = parseInt(x, 10);
y = parseInt(y, 10);

10 means a base-10 number.

See this link for an explanation of why the radix is necessary.

How to replace master branch in Git, entirely, from another branch?

You can rename/remove master on remote, but this will be an issue if lots of people have based their work on the remote master branch and have pulled that branch in their local repo.
That might not be the case here since everyone seems to be working on branch 'seotweaks'.

In that case you can:
git remote --show may not work. (Make a git remote show to check how your remote is declared within your local repo. I will assume 'origin')
(Regarding GitHub, house9 comments: "I had to do one additional step, click the 'Admin' button on GitHub and set the 'Default Branch' to something other than 'master', then put it back afterwards")

git branch -m master master-old  # rename master on local
git push origin :master          # delete master on remote
git push origin master-old       # create master-old on remote
git checkout -b master seotweaks # create a new local master on top of seotweaks
git push origin master           # create master on remote

But again:

  • if other users try to pull while master is deleted on remote, their pulls will fail ("no such ref on remote")
  • when master is recreated on remote, a pull will attempt to merge that new master on their local (now old) master: lots of conflicts. They actually need to reset --hard their local master to the remote/master branch they will fetch, and forget about their current master.

Send a file via HTTP POST with C#

To post files as from byte arrays:

private static string UploadFilesToRemoteUrl(string url, IList<byte[]> files, NameValueCollection nvc) {

        string boundary = "----------------------------" + DateTime.Now.Ticks.ToString("x");

        var request = (HttpWebRequest) WebRequest.Create(url);
        request.ContentType = "multipart/form-data; boundary=" + boundary;
        request.Method = "POST";
        request.KeepAlive = true;
        var postQueue = new ByteArrayCustomQueue();

        var formdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\";\r\n\r\n{1}";

        foreach (string key in nvc.Keys) {
            var formitem = string.Format(formdataTemplate, key, nvc[key]);
            var formitembytes = Encoding.UTF8.GetBytes(formitem);
            postQueue.Write(formitembytes);
        }

        var headerTemplate = "\r\n--" + boundary + "\r\n" +
            "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n" + 
            "Content-Type: application/zip\r\n\r\n";

        var i = 0;
        foreach (var file in files) {
            var header = string.Format(headerTemplate, "file" + i, "file" + i + ".zip");
            var headerbytes = Encoding.UTF8.GetBytes(header);
            postQueue.Write(headerbytes);
            postQueue.Write(file);
            i++;
        }

        postQueue.Write(Encoding.UTF8.GetBytes("\r\n--" + boundary + "--"));

        request.ContentLength = postQueue.Length;

        using (var requestStream = request.GetRequestStream()) {
            postQueue.CopyToStream(requestStream);
            requestStream.Close();
        }

        var webResponse2 = request.GetResponse();

        using (var stream2 = webResponse2.GetResponseStream())
        using (var reader2 = new StreamReader(stream2)) {

            var res =  reader2.ReadToEnd();
            webResponse2.Close();
            return res;
        }
    }

public class ByteArrayCustomQueue {

    private LinkedList<byte[]> arrays = new LinkedList<byte[]>();

    /// <summary>
    /// Writes the specified data.
    /// </summary>
    /// <param name="data">The data.</param>
    public void Write(byte[] data) {
        arrays.AddLast(data);
    }

    /// <summary>
    /// Gets the length.
    /// </summary>
    /// <value>
    /// The length.
    /// </value>
    public int Length { get { return arrays.Sum(x => x.Length); } }

    /// <summary>
    /// Copies to stream.
    /// </summary>
    /// <param name="requestStream">The request stream.</param>
    /// <exception cref="System.NotImplementedException"></exception>
    public void CopyToStream(Stream requestStream) {
        foreach (var array in arrays) {
            requestStream.Write(array, 0, array.Length);
        }
    }
}

Git push failed, "Non-fast forward updates were rejected"

Pull changes first:

git pull origin branch_name

Easiest way to read from and write to files

These are the best and most commonly used methods for writing to and reading from files:

using System.IO;

File.AppendAllText(sFilePathAndName, sTextToWrite);//add text to existing file
File.WriteAllText(sFilePathAndName, sTextToWrite);//will overwrite the text in the existing file. If the file doesn't exist, it will create it. 
File.ReadAllText(sFilePathAndName);

The old way, which I was taught in college was to use stream reader/stream writer, but the File I/O methods are less clunky and require fewer lines of code. You can type in "File." in your IDE (make sure you include the System.IO import statement) and see all the methods available. Below are example methods for reading/writing strings to/from text files (.txt.) using a Windows Forms App.

Append text to an existing file:

private void AppendTextToExistingFile_Click(object sender, EventArgs e)
{
    string sTextToAppend = txtMainUserInput.Text;
    //first, check to make sure that the user entered something in the text box.
    if (sTextToAppend == "" || sTextToAppend == null)
    {MessageBox.Show("You did not enter any text. Please try again");}
    else
    {
        string sFilePathAndName = getFileNameFromUser();// opens the file dailog; user selects a file (.txt filter) and the method returns a path\filename.txt as string.
        if (sFilePathAndName == "" || sFilePathAndName == null)
        {
            //MessageBox.Show("You cancalled"); //DO NOTHING
        }
        else 
        {
            sTextToAppend = ("\r\n" + sTextToAppend);//create a new line for the new text
            File.AppendAllText(sFilePathAndName, sTextToAppend);
            string sFileNameOnly = sFilePathAndName.Substring(sFilePathAndName.LastIndexOf('\\') + 1);
            MessageBox.Show("Your new text has been appended to " + sFileNameOnly);
        }//end nested if/else
    }//end if/else

}//end method AppendTextToExistingFile_Click

Get file name from the user via file explorer/open file dialog (you will need this to select existing files).

private string getFileNameFromUser()//returns file path\name
{
    string sFileNameAndPath = "";
    OpenFileDialog fd = new OpenFileDialog();
    fd.Title = "Select file";
    fd.Filter = "TXT files|*.txt";
    fd.InitialDirectory = Environment.CurrentDirectory;
    if (fd.ShowDialog() == DialogResult.OK)
    {
        sFileNameAndPath = (fd.FileName.ToString());
    }
    return sFileNameAndPath;
}//end method getFileNameFromUser

Get text from an existing file:

private void btnGetTextFromExistingFile_Click(object sender, EventArgs e)
{
    string sFileNameAndPath = getFileNameFromUser();
    txtMainUserInput.Text = File.ReadAllText(sFileNameAndPath); //display the text
}

Are there any standard exit status codes in Linux?

Part 1: Advanced Bash Scripting Guide

As always, the Advanced Bash Scripting Guide has great information: (This was linked in another answer, but to a non-canonical URL.)

1: Catchall for general errors
2: Misuse of shell builtins (according to Bash documentation)
126: Command invoked cannot execute
127: "command not found"
128: Invalid argument to exit
128+n: Fatal error signal "n"
255: Exit status out of range (exit takes only integer args in the range 0 - 255)

Part 2: sysexits.h

The ABSG references sysexits.h.

On Linux:

$ find /usr -name sysexits.h
/usr/include/sysexits.h
$ cat /usr/include/sysexits.h

/*
 * Copyright (c) 1987, 1993
 *  The Regents of the University of California.  All rights reserved.

 (A whole bunch of text left out.)

#define EX_OK           0       /* successful termination */
#define EX__BASE        64      /* base value for error messages */
#define EX_USAGE        64      /* command line usage error */
#define EX_DATAERR      65      /* data format error */
#define EX_NOINPUT      66      /* cannot open input */    
#define EX_NOUSER       67      /* addressee unknown */    
#define EX_NOHOST       68      /* host name unknown */
#define EX_UNAVAILABLE  69      /* service unavailable */
#define EX_SOFTWARE     70      /* internal software error */
#define EX_OSERR        71      /* system error (e.g., can't fork) */
#define EX_OSFILE       72      /* critical OS file missing */
#define EX_CANTCREAT    73      /* can't create (user) output file */
#define EX_IOERR        74      /* input/output error */
#define EX_TEMPFAIL     75      /* temp failure; user is invited to retry */
#define EX_PROTOCOL     76      /* remote error in protocol */
#define EX_NOPERM       77      /* permission denied */
#define EX_CONFIG       78      /* configuration error */

#define EX__MAX 78      /* maximum listed value */

How to create a self-signed certificate with OpenSSL

Am I missing something? Is this the correct way to build a self-signed certificate?

It's easy to create a self-signed certificate. You just use the openssl req command. It can be tricky to create one that can be consumed by the largest selection of clients, like browsers and command line tools.

It's difficult because the browsers have their own set of requirements, and they are more restrictive than the IETF. The requirements used by browsers are documented at the CA/Browser Forums (see references below). The restrictions arise in two key areas: (1) trust anchors, and (2) DNS names.

Modern browsers (like the warez we're using in 2014/2015) want a certificate that chains back to a trust anchor, and they want DNS names to be presented in particular ways in the certificate. And browsers are actively moving against self-signed server certificates.

Some browsers don't exactly make it easy to import a self-signed server certificate. In fact, you can't with some browsers, like Android's browser. So the complete solution is to become your own authority.

In the absence of becoming your own authority, you have to get the DNS names right to give the certificate the greatest chance of success. But I would encourage you to become your own authority. It's easy to become your own authority, and it will sidestep all the trust issues (who better to trust than yourself?).


This is probably not the site you are looking for!
The site's security certificate is not trusted!

This is because browsers use a predefined list of trust anchors to validate server certificates. A self-signed certificate does not chain back to a trusted anchor.

The best way to avoid this is:

  1. Create your own authority (i.e., become a CA)
  2. Create a certificate signing request (CSR) for the server
  3. Sign the server's CSR with your CA key
  4. Install the server certificate on the server
  5. Install the CA certificate on the client

Step 1 - Create your own authority just means to create a self-signed certificate with CA: true and proper key usage. That means the Subject and Issuer are the same entity, CA is set to true in Basic Constraints (it should also be marked as critical), key usage is keyCertSign and crlSign (if you are using CRLs), and the Subject Key Identifier (SKI) is the same as the Authority Key Identifier (AKI).

To become your own certificate authority, see *How do you sign a certificate signing request with your certification authority? on Stack Overflow. Then, import your CA into the Trust Store used by the browser.

Steps 2 - 4 are roughly what you do now for a public facing server when you enlist the services of a CA like Startcom or CAcert. Steps 1 and 5 allows you to avoid the third-party authority, and act as your own authority (who better to trust than yourself?).

The next best way to avoid the browser warning is to trust the server's certificate. But some browsers, like Android's default browser, do not let you do it. So it will never work on the platform.

The issue of browsers (and other similar user agents) not trusting self-signed certificates is going to be a big problem in the Internet of Things (IoT). For example, what is going to happen when you connect to your thermostat or refrigerator to program it? The answer is, nothing good as far as the user experience is concerned.

The W3C's WebAppSec Working Group is starting to look at the issue. See, for example, Proposal: Marking HTTP As Non-Secure.


How to create a self-signed certificate with OpenSSL

The commands below and the configuration file create a self-signed certificate (it also shows you how to create a signing request). They differ from other answers in one respect: the DNS names used for the self signed certificate are in the Subject Alternate Name (SAN), and not the Common Name (CN).

The DNS names are placed in the SAN through the configuration file with the line subjectAltName = @alternate_names (there's no way to do it through the command line). Then there's an alternate_names section in the configuration file (you should tune this to suit your taste):

[ alternate_names ]

DNS.1       = example.com
DNS.2       = www.example.com
DNS.3       = mail.example.com
DNS.4       = ftp.example.com

# Add these if you need them. But usually you don't want them or
#   need them in production. You may need them for development.
# DNS.5       = localhost
# DNS.6       = localhost.localdomain
# IP.1        = 127.0.0.1
# IP.2        = ::1

It's important to put DNS name in the SAN and not the CN, because both the IETF and the CA/Browser Forums specify the practice. They also specify that DNS names in the CN are deprecated (but not prohibited). If you put a DNS name in the CN, then it must be included in the SAN under the CA/B policies. So you can't avoid using the Subject Alternate Name.

If you don't do put DNS names in the SAN, then the certificate will fail to validate under a browser and other user agents which follow the CA/Browser Forum guidelines.

Related: browsers follow the CA/Browser Forum policies; and not the IETF policies. That's one of the reasons a certificate created with OpenSSL (which generally follows the IETF) sometimes does not validate under a browser (browsers follow the CA/B). They are different standards, they have different issuing policies and different validation requirements.


Create a self signed certificate (notice the addition of -x509 option):

openssl req -config example-com.conf -new -x509 -sha256 -newkey rsa:2048 -nodes \
    -keyout example-com.key.pem -days 365 -out example-com.cert.pem

Create a signing request (notice the lack of -x509 option):

openssl req -config example-com.conf -new -sha256 -newkey rsa:2048 -nodes \
    -keyout example-com.key.pem -days 365 -out example-com.req.pem

Print a self-signed certificate:

openssl x509 -in example-com.cert.pem -text -noout

Print a signing request:

openssl req -in example-com.req.pem -text -noout

Configuration file (passed via -config option)

[ req ]
default_bits        = 2048
default_keyfile     = server-key.pem
distinguished_name  = subject
req_extensions      = req_ext
x509_extensions     = x509_ext
string_mask         = utf8only

# The Subject DN can be formed using X501 or RFC 4514 (see RFC 4519 for a description).
#   Its sort of a mashup. For example, RFC 4514 does not provide emailAddress.
[ subject ]
countryName         = Country Name (2 letter code)
countryName_default     = US

stateOrProvinceName     = State or Province Name (full name)
stateOrProvinceName_default = NY

localityName            = Locality Name (eg, city)
localityName_default        = New York

organizationName         = Organization Name (eg, company)
organizationName_default    = Example, LLC

# Use a friendly name here because it's presented to the user. The server's DNS
#   names are placed in Subject Alternate Names. Plus, DNS names here is deprecated
#   by both IETF and CA/Browser Forums. If you place a DNS name here, then you
#   must include the DNS name in the SAN too (otherwise, Chrome and others that
#   strictly follow the CA/Browser Baseline Requirements will fail).
commonName          = Common Name (e.g. server FQDN or YOUR name)
commonName_default      = Example Company

emailAddress            = Email Address
emailAddress_default        = [email protected]

# Section x509_ext is used when generating a self-signed certificate. I.e., openssl req -x509 ...
[ x509_ext ]

subjectKeyIdentifier        = hash
authorityKeyIdentifier    = keyid,issuer

# You only need digitalSignature below. *If* you don't allow
#   RSA Key transport (i.e., you use ephemeral cipher suites), then
#   omit keyEncipherment because that's key transport.
basicConstraints        = CA:FALSE
keyUsage            = digitalSignature, keyEncipherment
subjectAltName          = @alternate_names
nsComment           = "OpenSSL Generated Certificate"

# RFC 5280, Section 4.2.1.12 makes EKU optional
#   CA/Browser Baseline Requirements, Appendix (B)(3)(G) makes me confused
#   In either case, you probably only need serverAuth.
# extendedKeyUsage    = serverAuth, clientAuth

# Section req_ext is used when generating a certificate signing request. I.e., openssl req ...
[ req_ext ]

subjectKeyIdentifier        = hash

basicConstraints        = CA:FALSE
keyUsage            = digitalSignature, keyEncipherment
subjectAltName          = @alternate_names
nsComment           = "OpenSSL Generated Certificate"

# RFC 5280, Section 4.2.1.12 makes EKU optional
#   CA/Browser Baseline Requirements, Appendix (B)(3)(G) makes me confused
#   In either case, you probably only need serverAuth.
# extendedKeyUsage    = serverAuth, clientAuth

[ alternate_names ]

DNS.1       = example.com
DNS.2       = www.example.com
DNS.3       = mail.example.com
DNS.4       = ftp.example.com

# Add these if you need them. But usually you don't want them or
#   need them in production. You may need them for development.
# DNS.5       = localhost
# DNS.6       = localhost.localdomain
# DNS.7       = 127.0.0.1

# IPv6 localhost
# DNS.8     = ::1

You may need to do the following for Chrome. Otherwise Chrome may complain a Common Name is invalid (ERR_CERT_COMMON_NAME_INVALID). I'm not sure what the relationship is between an IP address in the SAN and a CN in this instance.

# IPv4 localhost
# IP.1       = 127.0.0.1

# IPv6 localhost
# IP.2     = ::1

There are other rules concerning the handling of DNS names in X.509/PKIX certificates. Refer to these documents for the rules:

RFC 6797 and RFC 7469 are listed, because they are more restrictive than the other RFCs and CA/B documents. RFCs 6797 and 7469 do not allow an IP address, either.

Pandas: how to change all the values of a column?

You can do a column transformation by using apply

Define a clean function to remove the dollar and commas and convert your data to float.

def clean(x):
    x = x.replace("$", "").replace(",", "").replace(" ", "")
    return float(x)

Next, call it on your column like this.

data['Revenue'] = data['Revenue'].apply(clean)

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

If you really gotta be fast (not that I believe you do):

char[] chars = sourceDate.toCharArray();
chars[10] = ' ';
String targetDate = new String(chars, 0, 19);

Enabling SSL with XAMPP

I finally got this to work on my own hosted xampp windows 10 server web site. I.e. padlocks came up as ssl. I am using xampp version from November 2020.

  1. Went to certbot.eff.org. Selected from their home page software [apache] and system [windows]. Then downloaded and installed certbot software found at the next page into my C drive.

  2. Then from command line [cmd in Windows Start and then before you open cmd right click to run cmd as admin] I enhtered the command from Certbot page above. I.e. navigated to system32-- C:\WINDOWS\system32> certbot certonly --standalone

  3. Then followed the prompts and enteredmy domain name. This created certs as cert1.pem and key1.pem in C:\Certbot yourwebsitedomain folder. the cmd windows tells you where these are.

  4. Then took these and changed their names from cert1.pem to my domainname or shorter+cert.pem and same for domainname or shorter+key.key. Copied these into C:\xampp\apache\ssl.crt and ssl.key folders respectively.

  5. Then for G:\xampp\apache\conf\extra\httpd-vhosts entered the following:

<VirtualHost *:443>
    DocumentRoot "G:/xampp/htdocs/yourwebsitedomainname.hopto.org/public/" ###NB My document root is public.  Yours may not be.  Or could have an index.php page before /public###
    ServerName yourwebsitedomainnamee.hopto.org 
    <Directory G:/xampp/htdocs/yourwebsitedomainname.hopto.org>
        Options Indexes FollowSymLinks Includes ExecCGI
        AllowOverride All
        Require all granted
    </Directory>
    ErrorLog "G:/xampp/apache/logs/error.log"
    CustomLog "G:/xampp/apache/logs/access.log" common
    SSLEngine on
SSLCertificateFile "G:\xampp\apache\conf\ssl.crt\abscert.pem"
SSLCertificateKeyFile "G:\xampp\apache\conf\ssl.key\abskey.pem"
</VirtualHost>  
     
  1. Then navigated to G:\xampp\apache\conf\extra\httpd-ssl.conf and did as was advised above. I missed this important step for days until I read this post. Thank you! I.e. entered
<VirtualHost _default_:443>
DocumentRoot "G:/xampp/htdocs/yourwebsitedomainnamee.hopto.org/public/"
###NB My document root is public.  Yours may not be.  Or could have an index.php page before /public###
SSLEngine on
SSLCertificateFile "conf/ssl.crt/abscert.pem"
SSLCertificateKeyFile "conf/ssl.key/abskey.pem"
CustomLog "G:/xampp/apache/logs/ssl_request.log" \
          "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"
</VirtualHost>  

Note1. I used www.noip.com to register the domain name. Note2. Rather then try to get them to give me a ssl certificate, as I could not get it to work, the above worked instead. Note3 I use the noip DUC software to keep my personally hosted web site in sync with noip. Note4. Very important to stop and start xampp server after each change you make in xampp. If xampp fails for some reason instead of starting the xampp consol try the start xampp as this will give you problems you can bug fix. Copy these quickly and paste into note.txt.

Heroku "psql: FATAL: remaining connection slots are reserved for non-replication superuser connections"

You either need to increase the max_connections configuration setting or (probably better) use connection pooling to route a large number of user requests through a smaller connection pool.

https://wiki.postgresql.org/wiki/Number_Of_Database_Connections

Start/Stop and Restart Jenkins service on Windows

To stop Jenkins Please avoid shutting down the Java process or the Windows service. These are not usual commands. Use those only if your Jenkins is causing problems.

Use Jenkins' way to stop that protects from data loss.

http://[jenkins-server]/[command]

where [command] can be any one of the following

  • exit
  • restart
  • reload

Example: if my local PC is running Jenkins at port 8080, it will be

http://localhost:8080/exit

How to get a value from a Pandas DataFrame and not the index and object type

Use the values attribute to return the values as a np array and then use [0] to get the first value:

In [4]:
df.loc[df.Letters=='C','Letters'].values[0]

Out[4]:
'C'

EDIT

I personally prefer to access the columns using subscript operators:

df.loc[df['Letters'] == 'C', 'Letters'].values[0]

This avoids issues where the column names can have spaces or dashes - which mean that accessing using ..

What does functools.wraps do?

this is the source code about wraps:

WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__doc__')

WRAPPER_UPDATES = ('__dict__',)

def update_wrapper(wrapper,
                   wrapped,
                   assigned = WRAPPER_ASSIGNMENTS,
                   updated = WRAPPER_UPDATES):

    """Update a wrapper function to look like the wrapped function

       wrapper is the function to be updated
       wrapped is the original function
       assigned is a tuple naming the attributes assigned directly
       from the wrapped function to the wrapper function (defaults to
       functools.WRAPPER_ASSIGNMENTS)
       updated is a tuple naming the attributes of the wrapper that
       are updated with the corresponding attribute from the wrapped
       function (defaults to functools.WRAPPER_UPDATES)
    """
    for attr in assigned:
        setattr(wrapper, attr, getattr(wrapped, attr))
    for attr in updated:
        getattr(wrapper, attr).update(getattr(wrapped, attr, {}))
    # Return the wrapper so this can be used as a decorator via partial()
    return wrapper

def wraps(wrapped,
          assigned = WRAPPER_ASSIGNMENTS,
          updated = WRAPPER_UPDATES):
    """Decorator factory to apply update_wrapper() to a wrapper function

   Returns a decorator that invokes update_wrapper() with the decorated
   function as the wrapper argument and the arguments to wraps() as the
   remaining arguments. Default arguments are as for update_wrapper().
   This is a convenience function to simplify applying partial() to
   update_wrapper().
    """
    return partial(update_wrapper, wrapped=wrapped,
                   assigned=assigned, updated=updated)

C# Public Enums in Classes

Just declare the enum outside the bounds of the class. Like this:

public enum card_suits
{
    Clubs,
    Hearts,
    Spades,
    Diamonds
}

public class Card
{
    ...
}

Remember that an enum is a type. You might also consider putting the enum in its own file if it's going to be used by other classes. (You're programming a card game and the suit is a very important attribute of the card that, in well-structured code, will need to be accessible by a number of classes.)

C++ Convert string (or char*) to wstring (or wchar_t*)

This variant of it is my favourite in real life. It converts the input, if it is valid UTF-8, to the respective wstring. If the input is corrupted, the wstring is constructed out of the single bytes. This is extremely helpful if you cannot really be sure about the quality of your input data.

std::wstring convert(const std::string& input)
{
    try
    {
        std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
        return converter.from_bytes(input);
    }
    catch(std::range_error& e)
    {
        size_t length = input.length();
        std::wstring result;
        result.reserve(length);
        for(size_t i = 0; i < length; i++)
        {
            result.push_back(input[i] & 0xFF);
        }
        return result;
    }
}

Why do Twitter Bootstrap tables always have 100% width?

Bootstrap 3:

Why fight it? Why not simply control your table width using the bootstrap grid?

<div class="row">
    <div class="col-sm-6">
        <table></table>
    </div>
</div>

This will create a table that is half (6 out of 12) of the width of the containing element.

I sometimes use inline styles as per the other answers, but it is discouraged.

Bootstrap 4:

Bootstrap 4 has some nice helper classes for width like w-25, w-50, w-75, w-100, and w-auto. This will make the table 50% width:

<table class="w-50"></table>

Here's the doc: https://getbootstrap.com/docs/4.0/utilities/sizing/