Programs & Examples On #Inline functions

By using keyword 'inline' in function definition, programmer can request that the (C/C++) compiler insert the complete body of the function in every place that the function is called, rather than generating code to call the function in the one place it is defined.

Benefits of inline functions in C++?

Why not make all functions inline by default? Because it's an engineering trade off. There are at least two types of "optimization": speeding up the program and reducing the size (memory footprint) of the program. Inlining generally speeds things up. It gets rid of the function call overhead, avoiding pushing then pulling parameters from the stack. However, it also makes the memory footprint of the program bigger, because every function call must now be replaced with the full code of the function. To make things even more complicated, remember that the CPU stores frequently used chunks of memory in a cache on the CPU for ultra-rapid access. If you make the program's memory image big enough, your program won't be able to use the cache efficiently, and in the worst case inlining could actually slow your program down. To some extent the compiler can calculate what the trade offs are, and may be able to make better decisions than you can, just looking at the source code.

Email Address Validation in Android on EditText

This is a sample method i created to validate email addresses, if the string parameter passed is a valid email address , it returns true, else false is returned.

private boolean validateEmailAddress(String emailAddress){
    String  expression="^[\\w\\-]([\\.\\w])+[\\w]+@([\\w\\-]+\\.)+[A-Z]{2,4}$";  
       CharSequence inputStr = emailAddress;  
       Pattern pattern = Pattern.compile(expression,Pattern.CASE_INSENSITIVE);  
       Matcher matcher = pattern.matcher(inputStr);  
       return matcher.matches();
}

Remove all occurrences of a value from a list?

You can use slice assignment if the original list must be modified, while still using an efficient list comprehension (or generator expression).

>>> x = [1, 2, 3, 4, 2, 2, 3]
>>> x[:] = (value for value in x if value != 2)
>>> x
[1, 3, 4, 3]

java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonFactory

If you are using springboot then jackson is added by default,

So the version of jackson you are adding manualy is probably conflicting with the one spring boot adds,

Try to delete the jackson dependencies from your pom,

If you need to override the version spring boots add, then you need to exclude it first and then add your own

ping response "Request timed out." vs "Destination Host unreachable"

As khaos said, a destination unreachable could also mean that something is blocking the way from or to your destination. For example an ACL that filters bad IP addresses.

Angular 2.0 and Modal Dialog

Here is my full implementation of modal bootstrap angular2 component:

I assume that in your main index.html file (with <html> and <body> tags) at the bottom of <body> tag you have:

  <script src="assets/js/jquery-2.1.1.js"></script>
  <script src="assets/js/bootstrap.min.js"></script>

modal.component.ts:

import { Component, Input, Output, ElementRef, EventEmitter, AfterViewInit } from '@angular/core';

declare var $: any;// this is very importnant (to work this line: this.modalEl.modal('show')) - don't do this (becouse this owerride jQuery which was changed by bootstrap, included in main html-body template): let $ = require('../../../../../node_modules/jquery/dist/jquery.min.js');

@Component({
  selector: 'modal',
  templateUrl: './modal.html',
})
export class Modal implements AfterViewInit {

    @Input() title:string;
    @Input() showClose:boolean = true;
    @Output() onClose: EventEmitter<any> = new EventEmitter();

    modalEl = null;
    id: string = uniqueId('modal_');

    constructor(private _rootNode: ElementRef) {}

    open() {
        this.modalEl.modal('show');
    }

    close() {
        this.modalEl.modal('hide');
    }

    closeInternal() { // close modal when click on times button in up-right corner
        this.onClose.next(null); // emit event
        this.close();
    }

    ngAfterViewInit() {
        this.modalEl = $(this._rootNode.nativeElement).find('div.modal');
    }

    has(selector) {
        return $(this._rootNode.nativeElement).find(selector).length;
    }
}

let modal_id: number = 0;
export function uniqueId(prefix: string): string {
    return prefix + ++modal_id;
}

modal.html:

<div class="modal inmodal fade" id="{{modal_id}}" tabindex="-1" role="dialog"  aria-hidden="true" #thisModal>
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header" [ngClass]="{'hide': !(has('mhead') || title) }">
                <button *ngIf="showClose" type="button" class="close" (click)="closeInternal()"><span aria-hidden="true">&times;</span><span class="sr-only">Close</span></button>
                <ng-content select="mhead"></ng-content>
                <h4 *ngIf='title' class="modal-title">{{ title }}</h4>
            </div>
            <div class="modal-body">
                <ng-content></ng-content>
            </div>

            <div class="modal-footer" [ngClass]="{'hide': !has('mfoot') }" >
                <ng-content select="mfoot"></ng-content>
            </div>
        </div>
    </div>
</div>

And example of usage in client Editor component: client-edit-component.ts:

import { Component } from '@angular/core';
import { ClientService } from './client.service';
import { Modal } from '../common';

@Component({
  selector: 'client-edit',
  directives: [ Modal ],
  templateUrl: './client-edit.html',
  providers: [ ClientService ]
})
export class ClientEdit {

    _modal = null;

    constructor(private _ClientService: ClientService) {}

    bindModal(modal) {this._modal=modal;}

    open(client) {
        this._modal.open();
        console.log({client});
    }

    close() {
        this._modal.close();
    }

}

client-edit.html:

<modal [title]='"Some standard title"' [showClose]='true' (onClose)="close()" #editModal>{{ bindModal(editModal) }}
    <mhead>Som non-standart title</mhead>
    Some contents
    <mfoot><button calss='btn' (click)="close()">Close</button></mfoot>
</modal>

Ofcourse title, showClose, <mhead> and <mfoot> ar optional parameters/tags.

Iterate over object keys in node.js

For simple iteration of key/values, sometimes libraries like underscorejs can be your friend.

const _ = require('underscore');

_.each(a, function (value, key) {
    // handle
});

just for reference

How can I repeat a character in Bash?

There's more than one way to do it.

Using a loop:

  • Brace expansion can be used with integer literals:

    for i in {1..100}; do echo -n =; done    
    
  • A C-like loop allows the use of variables:

    start=1
    end=100
    for ((i=$start; i<=$end; i++)); do echo -n =; done
    

Using the printf builtin:

printf '=%.0s' {1..100}

Specifying a precision here truncates the string to fit the specified width (0). As printf reuses the format string to consume all of the arguments, this simply prints "=" 100 times.

Using head (printf, etc) and tr:

head -c 100 < /dev/zero | tr '\0' '='
printf %100s | tr " " "="

How do I find the index of a character within a string in C?

Just subtract the string address from what strchr returns:

char *string = "qwerty";
char *e;
int index;

e = strchr(string, 'e');
index = (int)(e - string);

Note that the result is zero based, so in above example it will be 2.

HttpWebRequest-The remote server returned an error: (400) Bad Request

What type of authentication do you use? Send the credentials using the properties Ben said before and setup a cookie handler. You already allow redirection, check your webserver if any redirection occurs (NTLM auth does for sure). If there is a redirection you need to store the session which is mostly stored in a session cookie.

Chrome says my extension's manifest file is missing or unreadable

My problem was slightly different.

By default Eclipse saved my manifest.json as an ANSI encoded text file.

Solution:

  • Open in Notepad
  • File -> Save As
  • select UTF-8 from the encoding drop-down in the bottom left.
  • Save

What is the correct way to create a single-instance WPF application?

I can't find a short solution here so I hope someone will like this:

UPDATED 2018-09-20

Put this code in your Program.cs:

using System.Diagnostics;

static void Main()
{
    Process thisProcess = Process.GetCurrentProcess();
    Process[] allProcesses = Process.GetProcessesByName(thisProcess.ProcessName);
    if (allProcesses.Length > 1)
    {
        // Don't put a MessageBox in here because the user could spam this MessageBox.
        return;
    }

    // Optional code. If you don't want that someone runs your ".exe" with a different name:

    string exeName = AppDomain.CurrentDomain.FriendlyName;
    // in debug mode, don't forget that you don't use your normal .exe name.
    // Debug uses the .vshost.exe.
    if (exeName != "the name of your executable.exe") 
    {
        // You can add a MessageBox here if you want.
        // To point out to users that the name got changed and maybe what the name should be or something like that^^ 
        MessageBox.Show("The executable name should be \"the name of your executable.exe\"", 
            "Wrong executable name", MessageBoxButtons.OK, MessageBoxIcon.Error);
        return;
    }

    // Following code is default code:
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new MainForm());
}

How to set up Android emulator proxy settings

Install Proxifier in your host computer. Setup proxifier to use your proxy. You don't need to do anything else. You will be fine. Proxifier traps the calls from the system (including the android emulator) and route it through the configured proxy.

What is the height of Navigation Bar in iOS 7?

I got this answer from the book Programming iOS 7, section Bar Position and Bar Metrics

If a navigation bar or toolbar — or a search bar (discussed earlier in this chapter) — is to occupy the top of the screen, the iOS 7 convention is that its height should be increased to underlap the transparent status bar. To make this possible, iOS 7 introduces the notion of a bar position.

UIBarPositionTopAttached

Specifies that the bar is at the top of the screen, as well as its containing view. Bars with this position draw their background extended upwards, allowing their background content to show through the status bar. Available in iOS 7.0 and later.

scp with port number specified

scp help tells us that port is specified by uppercase P.

~$ scp
usage: scp [-12346BCpqrv] [-c cipher] [-F ssh_config] [-i identity_file]
           [-l limit] [-o ssh_option] [-P port] [-S program]
           [[user@]host1:]file1 ... [[user@]host2:]file2

Hope this helps.

Remove a marker from a GoogleMap

to clear all scribbles in the map use

map.clear()

jQuery toggle CSS?

I would use the toggleClass function in jQuery and define the CSS to the class e.g.

/* start of css */
#user_button.active {
    border-bottom-right-radius: 5px;
    border-bottom-left-radius: 5px;
    -webkit-border-bottom-right-radius: 5px; /* user-agent specific */
    -webkit-border-bottom-left-radius: 5px;
    -moz-border-radius-bottomright: 5px;
    -moz-border-radius-bottomleft: 5px; /* etc... */
}
/* start of js */
$('#user_button').click(function() {
    $('#user_options').toggle();
    $(this).toggleClass('active');
    return false;
})

How do I trim leading/trailing whitespace in a standard way?

Very late to the party...

Single-pass forward-scanning solution with no backtracking. Every character in the source string is tested exactly once twice. (So it should be faster than most of the other solutions here, especially if the source string has a lot of trailing spaces.)

This includes two solutions, one to copy and trim a source string into another destination string, and the other to trim the source string in place. Both functions use the same code.

The (modifiable) string is moved in-place, so the original pointer to it remains unchanged.

#include <stddef.h>
#include <ctype.h>

char * trim2(char *d, const char *s)
{
    // Sanity checks
    if (s == NULL  ||  d == NULL)
        return NULL;

    // Skip leading spaces        
    const unsigned char * p = (const unsigned char *)s;
    while (isspace(*p))
        p++;

    // Copy the string
    unsigned char * dst = (unsigned char *)d;   // d and s can be the same
    unsigned char * end = dst;
    while (*p != '\0')
    {
        if (!isspace(*dst++ = *p++))
            end = dst;
    }

    // Truncate trailing spaces
    *end = '\0';
    return d;
}

char * trim(char *s)
{
    return trim2(s, s);
}

C# importing class into another class doesn't work

using is for namespaces only - if both classes are in the same namespace just drop the using.

You have to reference the assembly created in the first step when you compile the .exe:

csc /t:library /out:MyClass.dll MyClass.cs
csc /reference:MyClass.dll /t:exe /out:MyProgram.exe MyMainClass.cs

You can make things simpler if you just compile the files together:

csc /t:exe /out:MyProgram.exe MyMainClass.cs MyClass.cs

or

csc /t:exe /out:MyProgram.exe *.cs

EDIT: Here's how the files should look like:

MyClass.cs:

namespace MyNamespace {
    public class MyClass {
        void stuff() {

        }
    }
}

MyMainClass.cs:

using System;

namespace MyNamespace {
    public class MyMainClass {
        static void Main() {
            MyClass test = new MyClass();
        }
    }
}

Html: Difference between cell spacing and cell padding

cellspacing and cell padding


Cell padding

is used for formatting purpose which is used to specify the space needed between the edges of the cells and also in the cell contents. The general format of specifying cell padding is as follows:

< table width="100" border="2" cellpadding="5">

The above adds 5 pixels of padding inside each cell .

Cell Spacing:

Cell spacing is one also used f formatting but there is a major difference between cell padding and cell spacing. It is as follows: Cell padding is used to set extra space which is used to separate cell walls from their contents. But in contrast cell spacing is used to set space between cells.

What is an undefined reference/unresolved external symbol error and how do I fix it?

Microsoft offers a #pragma to reference the correct library at link time;

#pragma comment(lib, "libname.lib")

In addition to the library path including the directory of the library, this should be the full name of the library.

How to insert data using wpdb

$wpdb->query("insert into ".$table_name." (name, email, country, country, course, message, datesent) values ('$name','$email', '$phone', '$country', '$course', '$message', )");

Postgresql Select rows where column = array

In my case, I needed to work with a column that has the data, so using IN() didn't work. Thanks to @Quassnoi for his examples. Here is my solution:

SELECT column(s) FROM table WHERE expr|column = ANY(STRING_TO_ARRAY(column,',')::INT[])

I spent almost 6 hours before I stumble on the post.

How do I declare a two dimensional array?

The following are equivalent and result in a two dimensional array:

$array = array(
    array(0, 1, 2),
    array(3, 4, 5),
);

or

$array = array();

$array[] = array(0, 1, 2);
$array[] = array(3, 4, 5);

How to make bootstrap column height to 100% row height?

You can solve that using display table.

Here is the updated JSFiddle that solves your problem.

CSS

.body {
    display: table;
    background-color: green;
}

.left-side {
    background-color: blue;
    float: none;
    display: table-cell;
    border: 1px solid;
}

.right-side {
    background-color: red;
    float: none;
    display: table-cell;
    border: 1px solid;
}

HTML

<div class="row body">
        <div class="col-xs-9 left-side">
            <p>sdfsdf</p>
            <p>sdfsdf</p>
            <p>sdfsdf</p>
            <p>sdfsdf</p>
            <p>sdfsdf</p>
            <p>sdfsdf</p>
        </div>
        <div class="col-xs-3 right-side">
            asdfdf
        </div>
    </div>

How to sort a HashSet?

This simple command did the trick for me:

myHashSet.toList.sorted

I used this within a print statement, so if you need to actually persist the ordering, you may need to use TreeSets or other structures proposed on this thread.

How to fix the session_register() deprecated issue?

Use $_SESSION directly to set variables. Like this:

$_SESSION['name'] = 'stack';

Instead of:

$name = 'stack';
session_register("name");

Read More Here

Formatting a number with leading zeros in PHP

Simple answer

$p = 1234567;
$p = sprintf("%08d",$p);

I'm not sure how to interpret the comment saying "It will never be more than 8 digits" and if it's referring to the input or the output. If it refers to the output you would have to have an additional substr() call to clip the string.

To clip the first 8 digits

$p = substr(sprintf('%08d', $p),0,8);

To clip the last 8 digits

$p = substr(sprintf('%08d', $p),-8,8);

java.net.SocketTimeoutException: Read timed out under Tomcat

Here are the basic instructions:-

  1. Locate the "server.xml" file in the "conf" folder beneath Tomcat's base directory (i.e. %CATALINA_HOME%/conf/server.xml).
  2. Open the file in an editor and search for <Connector.
  3. Locate the relevant connector that is timing out - this will typically be the HTTP connector, i.e. the one with protocol="HTTP/1.1".
  4. If a connectionTimeout value is set on the connector, it may need to be increased - e.g. from 20000 milliseconds (= 20 seconds) to 120000 milliseconds (= 2 minutes). If no connectionTimeout property value is set on the connector, the default is 60 seconds - if this is insufficient, the property may need to be added.
  5. Restart Tomcat

Cygwin - Makefile-error: recipe for target `main.o' failed

You see the two empty -D entries in the g++ command line? They're causing the problem. You must have values in the -D items e.g. -DWIN32

if you're insistent on using something like -D$(SYSTEM) -D$(ENVIRONMENT) then you can use something like:

SYSTEM ?= generic
ENVIRONMENT ?= generic

in the makefile which gives them default values.

Your output looks to be missing the all important output:

<command-line>:0:1: error: macro names must be identifiers
<command-line>:0:1: error: macro names must be identifiers

just to clarify, what actually got sent to g++ was -D -DWindows_NT, i.e. define a preprocessor macro called -DWindows_NT; which is of course not a valid identifier (similarly for -D -I.)

extract digits in a simple way from a python string

This regular expression handles floats as well

import re
re_float = re.compile(r'\d*\.?\d+')

You could also add a group to the expression that catches your weight units.

re_banana = re.compile(r'(?P<number>\d*\.?\d+)\s?(?P<uni>[a-zA-Z]+)')

You can access the named groups like this re_banana.match("200 kgm").group('number').

I think this should help you getting started.

XmlSerializer giving FileNotFoundException at constructor

This exception can also be trapped by a managed debugging assistant (MDA) called BindingFailure.

This MDA is useful if your application is designed to ship with pre-build serialization assemblies. We do this to increase performance for our application. It allows us to make sure that the pre-built serialization assemblies are being properly built by our build process, and loaded by the application without being re-built on the fly.

It's really not useful except in this scenario, because as other posters have said, when a binding error is trapped by the Serializer constructor, the serialization assembly is re-built at runtime. So you can usually turn it off.

Mongoose, update values in array of objects

model.update({"_id": 1, "items.id": "2"}, 
{$set: {"items.$.name": "yourValue","items.$.value": "yourvalue"}})

Mongodb document

SQL grammar for SELECT MIN(DATE)

An aggregate function requires a GROUP BY in standard SQL

This is "Get minimum date per title" in plain language

SELECT title, MIN(date) FROM table GROUP BY title

Most RDBMS and the standard require that column is either in the GROUP BY or in a functions (MIN, COUNT etc): MySQL is the notable exception with some extensions that give unpredictable behaviour

Remote Connections Mysql Ubuntu

I was facing the same problem when I was trying to connect Mysql to a Remote Server. I had found out that I had to change the bind-address to the current private IP address of the DB server. But when I was trying to add the bind-address =0.0.0.0 line in my.cnf file, it was not understanding the line when I tried to create a DB.

Upon searching, I found out the original place where bind-address was declared.

The actual declaration is in : /etc/mysql/mariadb.conf.d/50-server.cnf

Therefore I changed the bind-address directly there and then all seems working.

add a temporary column with a value

select field1, field2, NewField = 'example' from table1 

HTML5 best practices; section/header/aside/article elements

Actually, you are quite right when it comes to header/footer. Here is some basic information on how each of the major HTML5 tags can/should be used (I suggest reading the full source linked at the bottom):

section – Used for grouping together thematically-related content. Sounds like a div element, but it’s not. The div has no semantic meaning. Before replacing all your div’s with section elements, always ask yourself: “Is all of the content related?”

aside – Used for tangentially related content. Just because some content appears to the left or right of the main content isn’t enough reason to use the aside element. Ask yourself if the content within the aside can be removed without reducing the meaning of the main content. Pullquotes are an example of tangentially related content.

header – There is a crucial difference between the header element and the general accepted usage of header (or masthead). There’s usually only one header or ‘masthead’ in a page. In HTML5 you can have as many as you want. The spec defines it as “a group of introductory or navigational aids”. You can use a header in any section on your site. In fact, you probably should use a header within most of your sections. The spec describes the section element as “a thematic grouping of content, typically with a heading.”

nav – Intended for major navigation information. A group of links grouped together isn’t enough reason to use the nav element. Site-wide navigation, on the other hand belongs in a nav element.

footer – Sounds like its a description of the position, but its not. Footer elements contain informations about its containing element: who wrote it, copyright, links to related content, etc. Whereas we usually have one footer for an entire document, HTML5 allows us to also have footer within sections.

Source: https://clzd.me/html5-section-aside-header-nav-footer-elements-not-as-obvious-as-they-sound/

Additionally, here's a description on article, not found in the source above:

article – Used for element that specifies independent, self-contained content. An article should make sense on its own. Before replacing all your div’s with article elements, always ask yourself: “Is it possible to read it independently from the rest of the web site?”

Declare a variable in DB2 SQL

I imagine this forum posting, which I quote fully below, should answer the question.


Inside a procedure, function, or trigger definition, or in a dynamic SQL statement (embedded in a host program):

BEGIN ATOMIC
 DECLARE example VARCHAR(15) ;
 SET example = 'welcome' ;
 SELECT *
 FROM   tablename
 WHERE  column1 = example ;
END

or (in any environment):

WITH t(example) AS (VALUES('welcome'))
SELECT *
FROM   tablename, t
WHERE  column1 = example

or (although this is probably not what you want, since the variable needs to be created just once, but can be used thereafter by everybody although its content will be private on a per-user basis):

CREATE VARIABLE example VARCHAR(15) ;
SET example = 'welcome' ;
SELECT *
FROM   tablename
WHERE  column1 = example ;

Cache busting via params

It is safer to put the version number in the actual filename. This allows multiple versions to exist at once so you can roll out a new version and if any cached HTML pages still exist that are requesting the older version, they will get the version that works with their HTML.

Note, in one of the largest versioned deployments anywhere on the internet, jQuery uses version numbers in the actual filename and it safely allows multiple versions to co-exist without any special server-side logic (each version is just a different file).

This busts the cache once when you deploy new pages and new linked files (which is what you want) and from then on those versions can be effectively cached (which you also want).

Draw text in OpenGL ES

Look at the "Sprite Text" sample in the GLSurfaceView samples.

Map and filter an array at the same time

Use Array.prototy.filter itself

function renderOptions(options) {
    return options.filter(function(option){
        return !option.assigned;
    }).map(function (option) {
        return (someNewObject);
    });   
}

how to avoid extra blank page at end while printing?

if None of those works, try this

@media print {

    html, body {
      height:100vh; 
      margin: 0 !important; 
      padding: 0 !important;
      overflow: hidden;
    }

}

make sure it is 100vh

What does 'COLLATE SQL_Latin1_General_CP1_CI_AS' do?

The COLLATE keyword specify what kind of character set and rules (order, confrontation rules) you are using for string values.

For example in your case you are using Latin rules with case insensitive (CI) and accent sensitive (AS)

You can refer to this Documentation

How do I set ANDROID_SDK_HOME environment variable?

Copy your SDK path and assign it to the environment variable ANDROID_SDK_ROOT

Refer pic below:

enter image description here

Is there a vr (vertical rule) in html?

There is not.

Why? Probably because a table with two columns will do.

Removing whitespace from strings in Java

st.replaceAll("\\s+","") removes all whitespaces and non-visible characters (e.g., tab, \n).


st.replaceAll("\\s+","") and st.replaceAll("\\s","") produce the same result.

The second regex is 20% faster than the first one, but as the number consecutive spaces increases, the first one performs better than the second one.


Assign the value to a variable, if not used directly:

st = st.replaceAll("\\s+","")

How to convert a string to ASCII

Try Linq:

Result = string.Join("", input.ToCharArray().Where(x=> ((int)x) < 127));

This will filter out all non ascii characters. Now if you want an equivalent, try the following:

Result = string.Join("", System.Text.Encoding.ASCII.GetChars(System.Text.Encoding.ASCII.GetBytes(input.ToCharArray())));

How to create a floating action button (FAB) in android, using AppCompat v21?

There are a bunch of libraries out there add a FAB(Floating Action Button) in your app, Here are few of them i Know.

makovkastar's FAB

futuersimple's Composite FAB

Material Design library which includes FAB too

All these libraries are supported on pre-lollipop devices, minimum to api 8

Assign an initial value to radio button as checked

The other way to set default checked on radio buttons, especially if you're using angularjs is setting the 'ng-checked' flag to "true" eg: <input id="d_man" value="M" ng-disabled="some Value" type="radio" ng-checked="true">Man

the checked="checked" did not work for me..

Serializing enums with Jackson

@JsonFormat(shape= JsonFormat.Shape.OBJECT)
public enum SomeEnum

available since https://github.com/FasterXML/jackson-databind/issues/24

just tested it works with version 2.1.2

answer to TheZuck:

I tried your example, got Json:

{"events":[{"type":"ADMIN"}]}

My code:

@RequestMapping(value = "/getEvent") @ResponseBody
  public EventContainer getEvent() {
    EventContainer cont = new EventContainer();
    cont.setEvents(Event.values());
    return cont;
 }

class EventContainer implements Serializable {

  private Event[] events;

  public Event[] getEvents() {
    return events;
 }

 public void setEvents(Event[] events) {
   this.events = events;
 }
}

and dependencies are:

<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-annotations</artifactId>
  <version>${jackson.version}</version>
</dependency>

<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-core</artifactId>
  <version>${jackson.version}</version>
</dependency>

<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-databind</artifactId>
  <version>${jackson.version}</version>
  <exclusions>
    <exclusion>
      <artifactId>jackson-annotations</artifactId>
      <groupId>com.fasterxml.jackson.core</groupId>
    </exclusion>
    <exclusion>
      <artifactId>jackson-core</artifactId>
      <groupId>com.fasterxml.jackson.core</groupId>
    </exclusion>
  </exclusions>
</dependency>

<jackson.version>2.1.2</jackson.version>

JQuery $.each() JSON array object iteration

Assign the second variable for the $.each function() as well, makes it lot easier as it'll provide you the data (so you won't have to work with the indicies).

$.each(json, function(arrayID,group) {
            console.log('<a href="'+group.GROUP_ID+'">');
    $.each(group.EVENTS, function(eventID,eventData) {
            console.log('<p>'+eventData.SHORT_DESC+'</p>');
     });
});

Should print out everything you were trying in your question.

http://jsfiddle.net/niklasvh/hZsQS/

edit renamed the variables to make it bit easier to understand what is what.

How to insert image in mysql database(table)?

Please try below code

INSERT INTO xx_BLOB(ID,IMAGE) VALUES(1,LOAD_FILE('E:/Images/jack.jpg'));

What's the best way to center your HTML email content in the browser window (or email client preview pane)?

Align the table to center.

<table width="100%" border="0" cellspacing="0" cellpadding="0">
    <tr>
        <td align="center">
            Your Content
        </td>
    </tr>
</table>

Where you have "your content" if it is a table, set it to the desired width and you will have centred content.

Git: Create a branch from unstaged/uncommitted changes on master

If you want your current uncommited changes on the current branch to move to a new branch, use the following command to create a new branch and copy the uncommitted changes automatically.

git checkout -b branch_name

This will create a new branch from your current branch (assuming it to be master), copy the uncommited changes and switch to the new branch.

Add files to stage & commit your changes to the new branch.

git add .
git commit -m "First commit"

Since, a new branch is created, before pushing it to remote, you need to set the upstream. Use the below command to set the upstream and push it to remote.

git push --set-upstream origin feature/feature/NEWBRANCH

Once you hit this command, a new branch will be created at the remote and your new local branch will be pushed to remote.

Now, if you want to throw away your uncommited changes from master branch, use:

git checkout master -f

This will throw away any uncommitted local changes on checkout.

Call external javascript functions from java code

try {
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("JavaScript");
        System.out.println("okay1");
        FileInputStream fileInputStream = new FileInputStream("C:/Users/Kushan/eclipse-workspace/sureson.lk/src/main/webapp/js/back_end_response.js");
        System.out.println("okay2");
        if (fileInputStream != null){
         BufferedReader reader = new BufferedReader(new InputStreamReader(fileInputStream));
         engine.eval(reader);
         System.out.println("okay3");
        // Invocable javascriptEngine = null;
         System.out.println("okay4");
        Invocable invocableEngine = (Invocable)engine;
         System.out.println("okay5");
         int x=0;
         System.out.println("invocableEngine is : "+invocableEngine);
         Object object = invocableEngine.invokeFunction("backend_message",x);

         System.out.println("okay6");
        }
        }catch(Exception e) {
            System.out.println("erroe when calling js function"+ e);
        }

How to add an image to the "drawable" folder in Android Studio?

Install and use the Android Drawable Importer plugin:

https://github.com/winterDroid/android-drawable-importer-intellij-plugin

Instructions on how to install the plugin are on that page. It's called "Android Drawable Importer" in the plugin search results.

Once installed:

  1. right click on "res" folder and select New -> Batch Drawable Import
  2. hit the + and select your source image
  3. choose what resolution you want it considered and which other sizes to auto-generate for

Seems kind of ridiculous that Android Studio doesn't support this directly.

EDIT: But Xcode doesn't either so.... :-(

Could not find a version that satisfies the requirement <package>

After 2 hours of searching, I found a way to fix it with just one line of command. You need to know the version of the package (Just search up PACKAGE version).

Command:

python3 -m pip install --pre --upgrade PACKAGE==VERSION.VERSION.VERSION

How do I solve the "server DNS address could not be found" error on Windows 10?

There might be a problem with your DNS servers of the ISP. A computer by default uses the ISP's DNS servers. You can manually configure your DNS servers. It is free and usually better than your ISP.

  1. Go to Control Panel ? Network and Internet ? Network and Sharing Centre
  2. Click on Change Adapter settings.
  3. Right click on your connection icon (Wireless Network Connection or Local Area Connection) and select properties.
  4. Select Internet protocol version 4.
  5. Click on "Use the following DNS server address" and type either of the two DNS given below.

Google Public DNS

Preferred DNS server : 8.8.8.8
Alternate DNS server : 8.8.4.4

OpenDNS

Preferred DNS server : 208.67.222.222
Alternate DNS server : 208.67.220.220

What is the worst real-world macros/pre-processor abuse you've ever come across?

#define return if (std::random(1000) < 2) throw std::exception(); else return

this is just so evil. It's random, which means it fires in different places all the time, it changes return statement, which usually have some code on it that could fail all by itself, it changes innocent looking keyword that you won't ever get suspicious over and it uses exception from std space so you won't try to search through your sources to find it's source. Just brilliant.

How to select a record and update it, with a single queryset in Django?

This answer compares the above two approaches. If you want to update many objects in a single line, go for:

# Approach 1
MyModel.objects.filter(field1='Computer').update(field2='cool')

Otherwise you would have to iterate over the query set and update individual objects:

#Approach 2    
objects = MyModel.objects.filter(field1='Computer')
for obj in objects:
    obj.field2 = 'cool'
    obj.save()
  1. Approach 1 is faster because, it makes only one database query, compared to approach 2 which makes 'n+1' database queries. (For n items in the query set)

  2. Fist approach makes one db query ie UPDATE, the second one makes two: SELECT and then UPDATE.

  3. The tradeoff is that, suppose you have any triggers, like updating updated_on or any such related fields, it will not be triggered on direct update ie approach 1.

  4. Approach 1 is used on a queryset, so it is possible to update multiple objects at once, not in the case of approach 2.

PDF to image using Java

In Ghost4J library (http://ghost4j.sourceforge.net), since version 0.4.0 you can use a SimpleRenderer to do the job with few lines of code:

  1. Load PDF or PS file (use PSDocument class for that):

        PDFDocument document = new PDFDocument();
        document.load(new File("input.pdf"));
    
  2. Create the renderer

        SimpleRenderer renderer = new SimpleRenderer();
    
        // set resolution (in DPI)
        renderer.setResolution(300);
    
  3. Render

        List<Image> images = renderer.render(document);
    

Then you can do what you want with your image objects, for example, you can write them as PNG like this:

            for (int i = 0; i < images.size(); i++) {
                ImageIO.write((RenderedImage) images.get(i), "png", new File((i + 1) + ".png"));
            }

Note: Ghost4J uses the native Ghostscript C API so you need to have a Ghostscript installed on your box.

I hope it will help you :)

setOnItemClickListener on custom ListView

If it helps anyone, I found that the problem was I already had an android:onClick event in my layout file (which I inflated for the ListView rows). This was superseding the onItemClick event.

LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression

Just save the string to a temp variable and then use that in your expression:

var strItem = item.Key.ToString();

IQueryable<entity> pages = from p in context.pages
                           where  p.Serial == strItem
                           select p;

The problem arises because ToString() isn't really executed, it is turned into a MethodGroup and then parsed and translated to SQL. Since there is no ToString() equivalent, the expression fails.

Note:

Make sure you also check out Alex's answer regarding the SqlFunctions helper class that was added later. In many cases it can eliminate the need for the temporary variable.

How to connect to a remote Windows machine to execute commands using python?

do the client machines have python loaded? if so, I'm doing this with psexec

On my local machine, I use subprocess in my .py file to call a command line.

import subprocess
subprocess.call("psexec {server} -c {}") 

the -c copies the file to the server so i can run any executable file (which in your case could be a .bat full of connection tests or your .py file from above).

How to implement a custom AlertDialog View

The simplest lines of code that works for me are are follows:

AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setView(R.layout.layout_resource_id);
builder.show();

Whatever the type of layout(LinearLayout, FrameLayout, RelativeLayout) will work by setView and will just differ in the appearance and behavior.

How to pass variable number of arguments to a PHP function

Since PHP 5.6, a variable argument list can be specified with the ... operator.

function do_something($first, ...$all_the_others)
{
    var_dump($first);
    var_dump($all_the_others);
}

do_something('this goes in first', 2, 3, 4, 5);

#> string(18) "this goes in first"
#>
#> array(4) {
#>   [0]=>
#>   int(2)
#>   [1]=>
#>   int(3)
#>   [2]=>
#>   int(4)
#>   [3]=>
#>   int(5)
#> }

As you can see, the ... operator collects the variable list of arguments in an array.

If you need to pass the variable arguments to another function, the ... can still help you.

function do_something($first, ...$all_the_others)
{
    do_something_else($first, ...$all_the_others);
    // Which is translated to:
    // do_something_else('this goes in first', 2, 3, 4, 5);
}

Since PHP 7, the variable list of arguments can be forced to be all of the same type too.

function do_something($first, int ...$all_the_others) { /**/ }

What is the difference between ELF files and bin files?

some resources:

  1. ELF for the ARM architecture
    http://infocenter.arm.com/help/topic/com.arm.doc.ihi0044d/IHI0044D_aaelf.pdf
  2. ELF from wiki
    http://en.wikipedia.org/wiki/Executable_and_Linkable_Format

ELF format is generally the default output of compiling. if you use GNU tool chains, you can translate it to binary format by using objcopy, such as:

  arm-elf-objcopy -O binary [elf-input-file] [binary-output-file]

or using fromELF utility(built in most IDEs such as ADS though):

 fromelf -bin -o [binary-output-file] [elf-input-file]

JavaScript and Threads

With the HTML5 "side-specs" no need to hack javascript anymore with setTimeout(), setInterval(), etc.

HTML5 & Friends introduces the javascript Web Workers specification. It is an API for running scripts asynchronously and independently.

Links to the specification and a tutorial.

How to resolve "The requested URL was rejected. Please consult with your administrator." error?

Encountered this issue in chrome. Resolved by cleaning up related cookies. Note that you don't have to cleanup ALL your cookies.

CSS disable hover effect

Do this Html and the CSS is in the head tag. Just make a new class and in the css use this code snippet:

pointer-events:none;

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .buttonDisabled {
        pointer-events: none;
      }
    </style>
  </head>
  <body>
    <button class="buttonDisabled">Not-a-button</button>
  </body>
</html>

Auto height div with overflow and scroll when needed

This is a horizontal solution with the use of FlexBox and without the pesky absolute positioning.

_x000D_
_x000D_
body {_x000D_
  height: 100vh;_x000D_
  margin: 0;_x000D_
  display: flex;_x000D_
  flex-direction: row;_x000D_
}_x000D_
_x000D_
#left,_x000D_
#right {_x000D_
  flex-grow: 1;_x000D_
}_x000D_
_x000D_
#left {_x000D_
  background-color: lightgrey;_x000D_
  flex-basis: 33%;_x000D_
  flex-shrink: 0;_x000D_
}_x000D_
_x000D_
#right {_x000D_
  background-color: aliceblue;_x000D_
  display: flex;_x000D_
  flex-direction: row;_x000D_
  flex-basis: 66%;_x000D_
  overflow: scroll;   /* other browsers */_x000D_
  overflow: overlay;  /* Chrome */_x000D_
}_x000D_
_x000D_
.item {_x000D_
  width: 150px;_x000D_
  background-color: darkseagreen;_x000D_
  flex-shrink: 0;_x000D_
  margin-left: 10px;_x000D_
}
_x000D_
<html>_x000D_
_x000D_
<body>_x000D_
  <section id="left"></section>_x000D_
  <section id="right">_x000D_
    <div class="item"></div>_x000D_
    <div class="item"></div>_x000D_
    <div class="item"></div>_x000D_
  </section>_x000D_
</body>_x000D_
_x000D_
</html>
_x000D_
_x000D_
_x000D_

How to push changes to github after jenkins build completes?

Once you set your Global Jenkins credentials, you can apply this step:

stage('Update GIT') {
  steps {
    script {
      catchError(buildResult: 'SUCCESS', stageResult: 'FAILURE') {
        withCredentials([usernamePassword(credentialsId: 'example-secure', passwordVariable: 'GIT_PASSWORD', usernameVariable: 'GIT_USERNAME')]) {
            def encodedPassword = URLEncoder.encode("$GIT_PASSWORD",'UTF-8')
            sh "git config user.email [email protected]"
            sh "git config user.name example"
            sh "git add ."
            sh "git commit -m 'Triggered Build: ${env.BUILD_NUMBER}'"
            sh "git push https://${GIT_USERNAME}:${encodedPassword}@github.com/${GIT_USERNAME}/example.git"
        }
      }
    }
  }
}

How to close a Tkinter window by pressing a Button?

You can associate directly the function object window.destroy to the command attribute of your button:

button = Button (frame, text="Good-bye.", command=window.destroy)

This way you will not need the function close_window to close the window for you.

C# Set collection?

If you're using .NET 3.5, you can use HashSet<T>. It's true that .NET doesn't cater for sets as well as Java does though.

The Wintellect PowerCollections may help too.

How to present UIActionSheet iOS Swift?

Generetic Action Sheet working for Swift 4, 4.2, 5

If you like a generic version that you can call from every ViewController and in every project try this one:

class Alerts {
 static func showActionsheet(viewController: UIViewController, title: String, message: String, actions: [(String, UIAlertActionStyle)], completion: @escaping (_ index: Int) -> Void) {
    let alertViewController = UIAlertController(title: title, message: message, preferredStyle: .actionSheet)
    for (index, (title, style)) in actions.enumerated() {
        let alertAction = UIAlertAction(title: title, style: style) { (_) in
            completion(index)
        }
        alertViewController.addAction(alertAction)
     }
     viewController.present(alertViewController, animated: true, completion: nil)
    }
}

Call like this in your ViewController.

    var actions: [(String, UIAlertActionStyle)] = []
    actions.append(("Action 1", UIAlertActionStyle.default))
    actions.append(("Action 2", UIAlertActionStyle.destructive))
    actions.append(("Action 3", UIAlertActionStyle.cancel))

    //self = ViewController
    Alerts.showActionsheet(viewController: self, title: "D_My ActionTitle", message: "General Message in Action Sheet", actions: actions) { (index) in
        print("call action \(index)")
        /*
         results
         call action 0
         call action 1
         call action 2
         */
    }

enter image description here

Attention: Maybe you're wondering why I add Action 1/2/3 but got results like 0,1,2. In the line for (index, (title, style)) in actions.enumerated() I get the index of actions. Arrays always begin with the index 0. So the completion is 0,1,2.

If you like to set a enum, an id or another identifier I would recommend to hand over an object in parameter actions.

What is the difference between logical data model and conceptual data model?

In this table you can see the difference between each model: Difference between data models

See http://www.1keydata.com/datawarehousing/data-modeling-levels.html for more information and some data model examples.

How to delete from multiple tables in MySQL?

Use a JOIN in the DELETE statement.

DELETE p, pa
      FROM pets p
      JOIN pets_activities pa ON pa.id = p.pet_id
     WHERE p.order > :order
       AND p.pet_id = :pet_id

Alternatively you can use...

DELETE pa
      FROM pets_activities pa
      JOIN pets p ON pa.id = p.pet_id
 WHERE p.order > :order
   AND p.pet_id = :pet_id

...to delete only from pets_activities

See this.

For single table deletes, yet with referential integrity, there are other ways of doing with EXISTS, NOT EXISTS, IN, NOT IN and etc. But the one above where you specify from which tables to delete with an alias before the FROM clause can get you out of a few pretty tight spots more easily. I tend to reach out to an EXISTS in 99% of the cases and then there is the 1% where this MySQL syntax takes the day.

How to detect when a UIScrollView has finished scrolling

An alternative would be to use scrollViewWillEndDragging:withVelocity:targetContentOffset which is called whenever the user lifts the finger and contains the target content offset where the scroll will stop. Using this content offset in scrollViewDidScroll: correctly identifies when the scroll view has stopped scrolling.

private var targetY: CGFloat?
public func scrollViewWillEndDragging(_ scrollView: UIScrollView,
                                      withVelocity velocity: CGPoint,
                                      targetContentOffset: UnsafeMutablePointer<CGPoint>) {
       targetY = targetContentOffset.pointee.y
}
public func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if (scrollView.contentOffset.y == targetY) {
        print("finished scrolling")
    }

iOS 9 not opening Instagram app with URL SCHEME

For PayPal add below URL schemes :

enter image description here

Refer this link

Limiting double to 3 decimal places

double example = 3.1416789645;
double output = Convert.ToDouble(example.ToString("N3"));

Gray out image with CSS?

Here's an example that let's you set the color of the background. If you don't want to use float, then you might need to set the width and height manually. But even that really depends on the surrounding CSS/HTML.

<style>
#color {
  background-color: red;
  float: left;
}#opacity    {
    opacity : 0.4;
    filter: alpha(opacity=40); 
}
</style>

<div id="color">
  <div id="opacity">
    <img src="image.jpg" />
  </div>
</div>

How to SELECT WHERE NOT EXIST using LINQ?

The outcome sql will be different but the result should be the same:

var shifts = Shifts.Where(s => !EmployeeShifts.Where(es => es.ShiftID == s.ShiftID).Any());

Nested lists python

The question title is too wide and the author's need is more specific. In my case, I needed to extract all elements from nested list like in the example below:

Example:

input -> [1,2,[3,4]]
output -> [1,2,3,4]

The code below gives me the result, but I would like to know if anyone can create a simpler answer:

def get_elements_from_nested_list(l, new_l):
    if l is not None:
        e = l[0]
        if isinstance(e, list):
            get_elements_from_nested_list(e, new_l)
        else:
            new_l.append(e)
        if len(l) > 1:
            return get_elements_from_nested_list(l[1:], new_l)
        else:
            return new_l

Call of the method

l = [1,2,[3,4]]
new_l = []

get_elements_from_nested_list(l, new_l)

What is the difference between concurrent programming and parallel programming?

Concurrency and Parallelism Source

In a multithreaded process on a single processor, the processor can switch execution resources between threads, resulting in concurrent execution.

In the same multithreaded process in a shared-memory multiprocessor environment, each thread in the process can run on a separate processor at the same time, resulting in parallel execution.

When the process has fewer or as many threads as there are processors, the threads support system in conjunction with the operating environment ensure that each thread runs on a different processor.

For example, in a matrix multiplication that has the same number of threads and processors, each thread (and each processor) computes a row of the result.

How to position one element relative to another with jQuery?

Something like this?

$(menu).css("top", targetE1.y + "px"); 
$(menu).css("left", targetE1.x - widthOfMenu + "px");

How can I specify system properties in Tomcat configuration on startup?

(Update: If I could delete this answer I would, although since it's accepted, I can't. I'm updating the description to provide better guidance and discourage folks from using the poor practice I outlined in the original answer).

You can specify these parameters via context or environment parameters, such as in context.xml. See the sections titled "Context Parameters" and "Environment Entries" on this page:

http://tomcat.apache.org/tomcat-5.5-doc/config/context.html

As @netjeff points out, these values will be available via the Context.lookup(String) method and not as System parameters.

Another way to do specify these values is to define variables inside of the web.xml file of the web application you're deploying (see below). As @Roberto Lo Giacco points out, this is generally considered a poor practice since a deployed artifact should not be environment specific. However, below is the configuration snippet if you really want to do this:

<env-entry>
    <env-entry-name>SMTP_PASSWORD</env-entry-name>
    <env-entry-type>java.lang.String</env-entry-type>
    <env-entry-value>abc123ftw</env-entry-value>
</env-entry>

How to window.scrollTo() with a smooth effect

$('html, body').animate({scrollTop:1200},'50');

You can do this!

Should black box or white box testing be the emphasis for testers?

QA should focus on Black box testing. The main goal of QA is to test what the system does (do features meet requirements ?), not how it does it.

Anyway it should be hard for QA to do white box testing as most of QA guys aren't tech guys, so they usually test features through the UI (like users).

A step further, I think developpers too should focus on Black box testing. I disagree with this widespread association between Unit testing and White box testing but it may be just a question a vocabulary/scale. At the scale of a Unit test, the System Under Test is a class/method which has contract (through its signature) and the important point is to test what it does, not how. Moreover White box testing implies you know how the method will fill its contract, that seems incompatile with TDD to me.

IMHO if your SUT is so complex that you need to do white box testing, it's usually time for refactoring.

How to get row index number in R?

I'm interpreting your question to be about getting row numbers.

  • You can try as.numeric(rownames(df)) if you haven't set the rownames. Otherwise use a sequence of 1:nrow(df).
  • The which() function converts a TRUE/FALSE row index into row numbers.

How to set selected value from Combobox?

Try this:

KeyValuePair<string, string> pair = (KeyValuePair<string,string>)this.ComboBox.SelectedItem;

What's a clean way to stop mongod on Mac OS X?

It's probably because launchctl is managing your mongod instance. If you want to start and shutdown mongod instance, unload that first:

launchctl unload -w ~/Library/LaunchAgents/org.mongodb.mongod.plist

Then start mongod manually:

mongod -f path/to/mongod.conf --fork

You can find your mongod.conf location from ~/Library/LaunchAgents/org.mongodb.mongod.plist.

After that, db.shutdownServer() would work just fine.

Added Feb 22 2014:

If you have mongodb installed via homebrew, homebrew actually has a handy brew services command. To show current running services:

brew services list

To start mongodb:

brew services start mongodb-community

To stop mongodb if it's already running:

brew services stop mongodb-community

Update*

As edufinn pointed out in the comment, brew services is now available as user-defined command and can be installed with following command: brew tap gapple/services.

The point of test %eax %eax

test is a non-destructive and, it doesn't return the result of the operation but it sets the flags register accordingly. To know what it really tests for you need to check the following instruction(s). Often out is used to check a register against 0, possibly coupled with a jz conditional jump.

How do I handle Database Connections with Dapper in .NET?

I do it like this:

internal class Repository : IRepository {

    private readonly Func<IDbConnection> _connectionFactory;

    public Repository(Func<IDbConnection> connectionFactory) 
    {
        _connectionFactory = connectionFactory;
    }

    public IWidget Get(string key) {
        using(var conn = _connectionFactory()) 
        {
            return conn.Query<Widget>(
               "select * from widgets with(nolock) where widgetkey=@WidgetKey", new { WidgetKey=key });
        }
    }
}

Then, wherever I wire-up my dependencies (ex: Global.asax.cs or Startup.cs), I do something like:

var connectionFactory = new Func<IDbConnection>(() => {
    var conn = new SqlConnection(
        ConfigurationManager.ConnectionStrings["connectionString-name"];
    conn.Open();
    return conn;
});

Why declare unicode by string in python?

The header definition is to define the encoding of the code itself, not the resulting strings at runtime.

putting a non-ascii character like ? in the python script without the utf-8 header definition will throw a warning

error

How to fix Hibernate LazyInitializationException: failed to lazily initialize a collection of roles, could not initialize proxy - no Session

I believe rather than enabling eager fetch, it make sense to re-initialise your entity where its needed to avoid LazyInitializationException exception

Hibernate.initialize(your entity);

How to make div follow scrolling smoothly with jQuery?

This one is same on facebook:

_x000D_
_x000D_
<script>_x000D_
var valX = $(window).scrollTop();_x000D_
function syncScroll(target){_x000D_
 var valY = $(window).scrollTop();_x000D_
 var difYX = valY - valX;_x000D_
 var targetX = $(target).scrollTop();_x000D_
 if(valY > valX){_x000D_
  $(target).scrollTop(difYX);_x000D_
 }_x000D_
 if(difYX <= 0){_x000D_
  $(target).scrollTop(-20);_x000D_
 }_x000D_
}_x000D_
_x000D_
$(window).scroll(function(){_x000D_
 syncScroll('#demo');_x000D_
})_x000D_
</script>
_x000D_
body{_x000D_
  margin:0;_x000D_
  padding:0;_x000D_
  height:100%;_x000D_
}_x000D_
#demo{_x000D_
  position:fixed;_x000D_
  height:100vh;_x000D_
  overflow:hidden;_x000D_
  width:40%;_x000D_
}_x000D_
#content{_x000D_
  position:relative;_x000D_
  float:right;_x000D_
  width:60%;_x000D_
  color:red; _x000D_
}
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<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
<body>_x000D_
  <div id="demo">_x000D_
    <ul>_x000D_
      <li>_x000D_
        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
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"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
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"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
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    <ul>_x000D_
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  <div id="content">_x000D_
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        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
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"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
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        <p>_x000D_
"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>_x000D_
"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
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        <p>_x000D_
"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
      </li>_x000D_
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"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
      </li>  _x000D_
      <li>_x000D_
        <p>_x000D_
"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>_x000D_
"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
      </li>  _x000D_
      <li>_x000D_
        <p>_x000D_
"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
      </li>_x000D_
    <ul>_x000D_
   </div>   _x000D_
</body
_x000D_
_x000D_
_x000D_

Github "Updates were rejected because the remote contains work that you do not have locally."

This happens if you initialized a new github repo with README and/or LICENSE file

git remote add origin [//your github url]

//pull those changes

git pull origin master 

// or optionally, 'git pull origin master --allow-unrelated-histories' if you have initialized repo in github and also committed locally

//now, push your work to your new repo

git push origin master

Now you will be able to push your repository to github. Basically, you have to merge those new initialized files with your work. git pull fetches and merges for you. You can also fetch and merge if that suits you.

How do I convert a IPython Notebook into a Python file via commandline?

Jupytext is nice to have in your toolchain for such conversions. It allows not only conversion from a notebook to a script, but you can go back again from the script to notebook as well. And even have that notebook produced in executed form.

jupytext --to py notebook.ipynb                 # convert notebook.ipynb to a .py file
jupytext --to notebook notebook.py              # convert notebook.py to an .ipynb file with no outputs
jupytext --to notebook --execute notebook.py    # convert notebook.py to an .ipynb file and run it 

What is a "web service" in plain English?

For most sites you have HTML pages that you visit when you use your browser. These are human-readable pages (once rendered in your browser) where a lot of data might be crammed together, because it makes sense for humans.

Now imagine that someone else want to use some of that data. They could download your page and start filtering out all the "noise" to get the data they wanted, but most websites are not built in a way where data is 100% certain to be placed in the same spot for all elements, so in addition to being cumbersome it also becomes unreliable.

Enter web services.

A web service is something that a website chooses to offer to those who wish to read, update and/or delete data from your website. You might call it a "backdoor" to your data. Instead of presenting the data as part of a webpage it is provided in a pre-determined way where some of the more popular are XML and JSON. There are several ways to communicate with a webservice, some use SOAP, others have REST'ful web services, etc.

What is common for all web services is that they are the machine-readable equivelant to the webpages the site otherwise offers. This means that others who wish to use the data can send a request to get certain data back that is easy to parse and use. Some sites may require you to provide a username/password in the request, for sensitive data, while other sites allow anyone to extract whatever data they might need.

How to add an Access-Control-Allow-Origin header

In your file.php of request ajax, can set value header.

<?php header('Access-Control-Allow-Origin: *'); //for all ?>

is vs typeof

This should answer that question, and then some.

The second line, if (obj.GetType() == typeof(ClassA)) {}, is faster, for those that don't want to read the article.

(Be aware that they don't do the same thing)

Pure JavaScript Send POST Data Without a Form

You can send it and insert the data to the body:

var xhr = new XMLHttpRequest();
xhr.open("POST", yourUrl, true);
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.send(JSON.stringify({
    value: value
}));

By the way, for get request:

var xhr = new XMLHttpRequest();
// we defined the xhr

xhr.onreadystatechange = function () {
    if (this.readyState != 4) return;

    if (this.status == 200) {
        var data = JSON.parse(this.responseText);

        // we get the returned data
    }

    // end of state change: it can be after some time (async)
};

xhr.open('GET', yourUrl, true);
xhr.send();

Firebug like plugin for Safari browser

I work a lot with CSS panel and it's too slow in Safari Web Inspector. Apple knows about this problem and promise to fix this bug with freezes, except this thing web tools is much more powerful and convenient than firebug in mozilla, so waiting for fix.

Nested Git repositories?

You could add

/project_root/third_party_git_repository_used_by_my_project

to

/project_root/.gitignore

that should prevent the nested repo to be included in the parent repo, and you can work with them independently.

But: If a user runs git clean -dfx in the parent repo, it will remove the ignored nested repo. Another way is to symlink the folder and ignore the symlink. If you then run git clean, the symlink is removed, but the 'nested' repo will remain intact as it really resides elsewhere.

What is the difference between --save and --save-dev?

--save-dev is used for modules used in development of the application,not require while running it in production envionment --save is used to add it in package.json and it is required for running of the application.

Example: express,body-parser,lodash,helmet,mysql all these are used while running the application use --save to put in dependencies while mocha,istanbul,chai,sonarqube-scanner all are used during development ,so put those in dev-dependencies .

npm link or npm install will also install the dev-dependency modules along with dependency modules in your project folder

R - Markdown avoiding package loading messages

This is an old question, but here's another way to do it.

You can modify the R code itself instead of the chunk options, by wrapping the source call in suppressPackageStartupMessages(), suppressMessages(), and/or suppressWarnings(). E.g:

```{r echo=FALSE}
suppressWarnings(suppressMessages(suppressPackageStartupMessages({
source("C:/Rscripts/source.R")
})
```

You can also put those functions around your library() calls inside the "source.R" script.

Where to place the 'assets' folder in Android Studio?

In Android Studio 4.1.1

Right Click on your module (app for example) -> New -> Folder -> Assets Folder

enter image description here

Is <img> element block level or inline level?

It's true, they are both - or more precisely, they are "inline block" elements. This means that they flow inline like text, but also have a width and height like block elements.

How do I use shell variables in an awk script?

Use either of these depending how you want backslashes in the shell variables handled (avar is an awk variable, svar is a shell variable):

awk -v avar="$svar" '... avar ...' file
awk 'BEGIN{avar=ARGV[1];ARGV[1]=""}... avar ...' "$svar" file

See http://cfajohnson.com/shell/cus-faq-2.html#Q24 for details and other options. The first method above is almost always your best option and has the most obvious semantics.

Where is localhost folder located in Mac or Mac OS X?

Actually in newer Osx os's, this is stored in /Library/WebServer/Documents/

The .en file is just an html file, but it needs special permissions to change, so I just made a folder for my stuff and then accessed it by user.local/Folder/file.html

One line if/else condition in linux shell scripting

You can use like bellow:

(( var0 = var1<98?9:21 ))

the same as

if [ "$var1" -lt 98 ]; then
   var0=9
else
   var0=21
fi

extends

condition?result-if-true:result-if-false

I found the interested thing on the book "Advanced Bash-Scripting Guide"

Calculate mean across dimension in a 2D array

a.mean() takes an axis argument:

In [1]: import numpy as np

In [2]: a = np.array([[40, 10], [50, 11]])

In [3]: a.mean(axis=1)     # to take the mean of each row
Out[3]: array([ 25. ,  30.5])

In [4]: a.mean(axis=0)     # to take the mean of each col
Out[4]: array([ 45. ,  10.5])

Or, as a standalone function:

In [5]: np.mean(a, axis=1)
Out[5]: array([ 25. ,  30.5])

The reason your slicing wasn't working is because this is the syntax for slicing:

In [6]: a[:,0].mean() # first column
Out[6]: 45.0

In [7]: a[:,1].mean() # second column
Out[7]: 10.5

change html text from link with jquery

You need J-query library to do this simply:

<script src="//code.jquery.com/jquery-1.11.3.min.js"></script>

First you need to put your element in div like this:

<div id="divClickHere">
<a id="a_tbnotesverbergen" href="#nothing">click here</a>
</div>

Then you should write this J-Query Code:

<script type="text/javascript">
$(document).ready(function(){
$("#a_tbnotesverbergen").click(function(){
$("#divClickHere a").text('Your new text');
});
});
</script>

How do I get the current date and current time only respectively in Django?

Another way to get datetime UTC with milliseconds.

from datetime import datetime

datetime.utcnow().isoformat(sep='T', timespec='milliseconds') + 'Z'

2020-10-29T14:46:37.655Z

Simple dictionary in C++

A table out of char array:

char map[256] = { 0 };
map['T'] = 'A'; 
map['A'] = 'T';
map['C'] = 'G';
map['G'] = 'C';
/* .... */

How to insert logo with the title of a HTML page?

Are you referring to the favicon?

Upload a 16x16px ico to your site, and link it in your head section.

<link rel="shortcut icon" href="/favicon.ico" />

There are a multitude of sites that help you convert images into .ico format too. This is just the first one I saw on Google. http://www.favicon.cc/

"for line in..." results in UnicodeDecodeError: 'utf-8' codec can't decode byte

Your file doesn't actually contain UTF-8 encoded data; it contains some other encoding. Figure out what that encoding is and use it in the open call.

In Windows-1252 encoding, for example, the 0xe9 would be the character é.

A Simple, 2d cross-platform graphics library for c or c++?

What about SDL?

Perhaps it's a bit too complex for your needs, but it's certainly cross-platform.

Prevent overwriting a file using cmd if exist

I noticed some issues with this that might be useful for someone just starting, or a somewhat inexperienced user, to know. First...

CD /D "C:\Documents and Settings\%username%\Start Menu\Programs\"

two things one is that a /D after the CD may prove to be useful in making sure the directory is changed but it's not really necessary, second, if you are going to pass this from user to user you have to add, instead of your name, the code %username%, this makes the code usable on any computer, as long as they have your setup.exe file in the same location as you do on your computer. of course making sure of that is more difficult. also...

start \\filer\repo\lab\"software"\"myapp"\setup.exe

the start code here, can be set up like that, but the correct syntax is

start "\\filter\repo\lab\software\myapp\" setup.exe

This will run: setup.exe, located in: \filter\repo\lab...etc.\

Visual Studio Code Search and Replace with Regular Expressions

If you want ex. change all country codes in .json file from uppercase to lowercase:

ctrl+h
alt+r
alt+c

Find: ([A-Z]{2,})
Replace: $1

alt+enter
F1
type: lower -> select toLoweCase
ctrl+alt+enter

ex file:

[
 {"id": "PL", "name": "Poland"},
 {"id": "NZ", "name": "New Zealand"},
 ...
]

Using the star sign in grep

The "star sign" is only meaningful if there is something in front of it. If there isn't the tool (grep in this case) may just treat it as an error. For example:

'*xyz'    is meaningless
'a*xyz'   means zero or more occurrences of 'a' followed by xyz

Make the size of a heatmap bigger with seaborn

add plt.figure(figsize=(16,5)) before the sns.heatmap and play around with the figsize numbers till you get the desired size

...

plt.figure(figsize = (16,5))

ax = sns.heatmap(df1.iloc[:, 1:6:], annot=True, linewidths=.5)

How can I dynamically add items to a Java array?

keep a count of where you are in the primitive array

class recordStuff extends Thread
{
    double[] aListOfDoubles;
    int i = 0;

    void run()
    {
        double newData;
        newData = getNewData(); // gets data from somewhere

        aListofDoubles[i] = newData; // adds it to the primitive array of doubles
        i++ // increments the counter for the next pass

        System.out.println("mode: " + doStuff());
    }

    void doStuff()
    {
        // Calculate the mode of the double[] array

        for (int i = 0; i < aListOfDoubles.length; i++) 
        {
            int count = 0;
            for (int j = 0; j < aListOfDoubles.length; j++)
            {
                if (a[j] == a[i]) count++;
            }
            if (count > maxCount) 
            {
                maxCount = count;
                maxValue = aListOfDoubles[i];
            }
        }
        return maxValue;
    }
}

Listing information about all database files in SQL Server

Using this script you can show all the databases name and files used (with exception of system dbs).

select name,physical_name from sys.master_files where database_id > 4

How to get the date from jQuery UI datepicker

Try this, works like charm, gives the date you have selected. onsubmit form try to get this value:-

var date = $("#scheduleDate").datepicker({ dateFormat: 'dd,MM,yyyy' }).val();

Reference here

milliseconds to days

int days = (int) (milliseconds / 86 400 000 )

WPF Data Binding and Validation Rules Best Practices

Also check this article. Supposedly Microsoft released their Enterprise Library (v4.0) from their patterns and practices where they cover the validation subject but god knows why they didn't included validation for WPF, so the blog post I'm directing you to, explains what the author did to adapt it. Hope this helps!

What is the "__v" field in Mongoose

Well, I can't see Tony's solution...so I have to handle it myself...


If you don't need version_key, you can just:

var UserSchema = new mongoose.Schema({
    nickname: String,
    reg_time: {type: Date, default: Date.now}
}, {
    versionKey: false // You should be aware of the outcome after set to false
});

Setting the versionKey to false means the document is no longer versioned.

This is problematic if the document contains an array of subdocuments. One of the subdocuments could be deleted, reducing the size of the array. Later on, another operation could access the subdocument in the array at it's original position.

Since the array is now smaller, it may accidentally access the wrong subdocument in the array.

The versionKey solves this by associating the document with the a versionKey, used by mongoose internally to make sure it accesses the right collection version.

More information can be found at: http://aaronheckmann.blogspot.com/2012/06/mongoose-v3-part-1-versioning.html

How to resolve Error listenerStart when deploying web-app in Tomcat 5.5?

/var/lib/tomcat5.5/webapps/spaghetti/WEB-INF/lib/jsp-api-6.0.16.jar
/var/lib/tomcat5.5/webapps/spaghetti/WEB-INF/lib/servlet-api-6.0.16.jar

You should not have any server-specific libraries in the /WEB-INF/lib. Leave them in the appserver's own library. It would only lead to collisions in the classpath. Get rid of all appserver-specific libraries in /WEB-INF/lib (and also in JRE/lib and JRE/lib/ext if you have placed any of them there).

A common cause that the appserver-specific libraries are included in the webapp's library is that starters think that it is the right way to fix compilation errors of among others the javax.servlet classes not being resolveable. Putting them in webapp's library is the wrong solution. You should reference them in the classpath during compilation, i.e. javac -cp /path/to/server/lib/servlet.jar and so on, or if you're using an IDE, you should integrate the server in the IDE and associate the web project with the server. The IDE will then automatically take server-specific libraries in the classpath (buildpath) of the webapp project.

Why am I getting a FileNotFoundError?

A good start would be validating the input. In other words, you can make sure that the user has indeed typed a correct path for a real existing file, like this:

import os
fileName = input("Please enter the name of the file you'd like to use.")
while not os.path.isfile(fileName):
    fileName = input("Whoops! No such file! Please enter the name of the file you'd like to use.")

This is with a little help from the built in module os, That is a part of the Standard Python Library.

Check if a class `active` exist on element with jquery

$('li.menu.active')

is the simplest way. This will return all elements with both classes.

Or an already answered jQuery hasClass() - check for more than one class

Visualizing branch topology in Git

Git official site enlisted some third party platform specific GUI tools. Hit here git GUI Tools for Linux Platform

I have used gitg and GitKraken for linux platform. Both good to understand the commit tree

How to Use slideDown (or show) function on a table row?

The plug offered by Vinny is really close, but I found and fixed a couple of small issues.

  1. It greedily targeted td elements beyond just the children of the row being hidden. This would have been kind of ok if it had then sought out those children when showing the row. While it got close, they all ended up with "display: none" on them, rendering them hidden.
  2. It didn't target child th elements at all.
  3. For table cells with lots of content (like a nested table with lots of rows), calling slideRow('up'), regardless of the slideSpeed value provided, it'd collapse the view of the row as soon as the padding animation was done. I fixed it so the padding animation doesn't trigger until the slideUp() method on the wrapping is done.

    (function($){
        var sR = {
            defaults: {
                slideSpeed: 400
              , easing: false
              , callback: false
            }
          , thisCallArgs:{
                slideSpeed: 400
              , easing: false
              , callback: false
            }
          , methods:{
                up: function(arg1, arg2, arg3){
                    if(typeof arg1 == 'object'){
                        for(p in arg1){
                            sR.thisCallArgs.eval(p) = arg1[p];
                        }
                    }else if(typeof arg1 != 'undefined' && (typeof arg1 == 'number' || arg1 == 'slow' || arg1 == 'fast')){
                        sR.thisCallArgs.slideSpeed = arg1;
                    }else{
                        sR.thisCallArgs.slideSpeed = sR.defaults.slideSpeed;
                    }
    
                    if(typeof arg2 == 'string'){
                        sR.thisCallArgs.easing = arg2;
                    }else if(typeof arg2 == 'function'){
                        sR.thisCallArgs.callback = arg2;
                    }else if(typeof arg2 == 'undefined'){
                        sR.thisCallArgs.easing = sR.defaults.easing;    
                    }
                    if(typeof arg3 == 'function'){
                        sR.thisCallArgs.callback = arg3;
                    }else if(typeof arg3 == 'undefined' && typeof arg2 != 'function'){
                        sR.thisCallArgs.callback = sR.defaults.callback;    
                    }
                    var $cells = $(this).children('td, th');
                    $cells.wrapInner('<div class="slideRowUp" />');
                    var currentPadding = $cells.css('padding');
                    $cellContentWrappers = $(this).find('.slideRowUp');
                    $cellContentWrappers.slideUp(sR.thisCallArgs.slideSpeed, sR.thisCallArgs.easing, function(){
                        $(this).parent().animate({ paddingTop: '0px', paddingBottom: '0px' }, {
                            complete: function(){
                                $(this).children('.slideRowUp').replaceWith($(this).children('.slideRowUp').contents());
                                $(this).parent().css({ 'display': 'none' });
                                $(this).css({ 'padding': currentPadding });
                            }
                        });
                    });
                    var wait = setInterval(function(){
                        if($cellContentWrappers.is(':animated') === false){
                            clearInterval(wait);
                            if(typeof sR.thisCallArgs.callback == 'function'){
                                sR.thisCallArgs.callback.call(this);
                            }
                        }
                    }, 100);                                                                                                    
                    return $(this);
                }
              , down: function (arg1, arg2, arg3){
                    if(typeof arg1 == 'object'){
                        for(p in arg1){
                            sR.thisCallArgs.eval(p) = arg1[p];
                        }
                    }else if(typeof arg1 != 'undefined' && (typeof arg1 == 'number' || arg1 == 'slow' || arg1 == 'fast')){
                        sR.thisCallArgs.slideSpeed = arg1;
                    }else{
                        sR.thisCallArgs.slideSpeed = sR.defaults.slideSpeed;
                    }
    
                    if(typeof arg2 == 'string'){
                        sR.thisCallArgs.easing = arg2;
                    }else if(typeof arg2 == 'function'){
                        sR.thisCallArgs.callback = arg2;
                    }else if(typeof arg2 == 'undefined'){
                        sR.thisCallArgs.easing = sR.defaults.easing;    
                    }
                    if(typeof arg3 == 'function'){
                        sR.thisCallArgs.callback = arg3;
                    }else if(typeof arg3 == 'undefined' && typeof arg2 != 'function'){
                        sR.thisCallArgs.callback = sR.defaults.callback;    
                    }
                    var $cells = $(this).children('td, th');
                    $cells.wrapInner('<div class="slideRowDown" style="display:none;" />');
                    $cellContentWrappers = $cells.find('.slideRowDown');
                    $(this).show();
                    $cellContentWrappers.slideDown(sR.thisCallArgs.slideSpeed, sR.thisCallArgs.easing, function() { $(this).replaceWith( $(this).contents()); });
    
                    var wait = setInterval(function(){
                        if($cellContentWrappers.is(':animated') === false){
                            clearInterval(wait);
                            if(typeof sR.thisCallArgs.callback == 'function'){
                                sR.thisCallArgs.callback.call(this);
                            }
                        }
                    }, 100);
                    return $(this);
                }
            }
        };
    
        $.fn.slideRow = function(method, arg1, arg2, arg3){
            if(typeof method != 'undefined'){
                if(sR.methods[method]){
                    return sR.methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
                }
            }
        };
    })(jQuery);
    

How is VIP swapping + CNAMEs better than IP swapping + A records?

A VIP swap is an internal change to Azure's routers/load balancers, not an external DNS change. They're just routing traffic to go from one internal [set of] server[s] to another instead. Therefore the DNS info for mysite.cloudapp.net doesn't change at all. Therefore the change for people accessing via the IP bound to mysite.cloudapp.net (and CNAME'd by you) will see the change as soon as the VIP swap is complete.

Run java jar file on a server as background process

If you're using Ubuntu and have "Upstart" (http://upstart.ubuntu.com/) you can try this:

Create /var/init/yourservice.conf

with the following content

description "Your Java Service"  
author "You"  

start on runlevel [3]  
stop on shutdown  

expect fork  

script     
    cd /web 
    java -jar server.jar >/var/log/yourservice.log 2>&1  
    emit yourservice_running  
end script  

Now you can issue the service yourservice start and service yourservice stop commands. You can tail /var/log/yourservice.log to verify that it's working.

If you just want to run your jar from the console without it hogging the console window, you can just do:

java -jar /web/server.jar > /var/log/yourservice.log 2>&1

How to pass multiple arguments in processStartInfo?

System.Diagnostics.Process process = new System.Diagnostics.Process();
System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo();
startInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
startInfo.FileName = "cmd.exe";
startInfo.Arguments = @"/c -sk server -sky exchange -pe -n CN=localhost -ir LocalMachine -is Root -ic MyCA.cer -sr LocalMachine -ss My MyAdHocTestCert.cer"

use /c as a cmd argument to close cmd.exe once its finish processing your commands

C# : changing listbox row color?

Once you've added your listbox item to your form, change DrawMode with OwnerDrawFixed option from the Properties panel. If you forget to do this, none of the codes below will work. Then click DrawItem event from the Events area.

private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
{
   // 1. Get the item
   string selectedItem = listBox1.Items[e.Index].ToString();
                    
   // 2. Choose font 
   Font font = new Font("Arial", 12);
        
   // 3. Choose colour
   SolidBrush solidBrush = new SolidBrush(Color.Red);
        
   // 4. Get bounds
   int left = e.Bounds.Left;
   int top = e.Bounds.Top;
                    
   // 5. Use Draw the background within the bounds
   e.DrawBackground();
        
   // 6. Colorize listbox items
   e.Graphics.DrawString(selectedItem, font, solidBrush, left, top);
}

Does --disable-web-security Work In Chrome Anymore?

Just create this batch file and run it on windows. It basically would kill all chrome instances and then would start chrome with disabling security. Save the following script in batch file say ***.bat and double click on it.

TASKKILL /F /IM chrome.exe
start chrome.exe --args --disable-web-security –-allow-file-access-from-files

How do you normalize a file path in Bash?

I know this is an ancient question. I'm still offering an alternative. Recently I met the same issue and found no existing and portable command to do that. So I wrote the following shell script which includes a function that can do the trick.

#! /bin/sh                                                                                                                                                

function normalize {
  local rc=0
  local ret

  if [ $# -gt 0 ] ; then
    # invalid
    if [ "x`echo $1 | grep -E '^/\.\.'`" != "x" ] ; then
      echo $1
      return -1
    fi

    # convert to absolute path
    if [ "x`echo $1 | grep -E '^\/'`" == "x" ] ; then
      normalize "`pwd`/$1"
      return $?
    fi

    ret=`echo $1 | sed 's;/\.\($\|/\);/;g' | sed 's;/[^/]*[^/.]\+[^/]*/\.\.\($\|/\);/;g'`
  else
    read line
    normalize "$line"
    return $?
  fi

  if [ "x`echo $ret | grep -E '/\.\.?(/|$)'`" != "x" ] ; then
    ret=`normalize "$ret"`
    rc=$?
  fi

  echo "$ret"
  return $rc
}

https://gist.github.com/bestofsong/8830bdf3e5eb9461d27313c3c282868c

Can there exist two main methods in a Java program?

The below code in file "Locomotive.java" will compile and run successfully, with the execution results showing

2<SPACE>

As mentioned in above post, the overload rules still work for the main method. However, the entry point is the famous psvm (public static void main(String[] args))

public class Locomotive {
    Locomotive() { main("hi");}

    public static void main(String[] args) {
        System.out.print("2 ");
    }

    public static void main(String args) {
        System.out.print("3 " + args);
    }
}

How can I use Google's Roboto font on a website?

it's easy

every folder of those you downloaded has a different kind of roboto font, means they are different fonts

example: "roboto_regular_macroman"

to use any of them:

1- extract the folder of the font you want to use

2- upload it near the css file

3- now include it in the css file

example for including the font which called "roboto_regular_macroman":

@font-face {
font-family: 'Roboto';
src: url('roboto_regular_macroman/Roboto-Regular-webfont.eot');
src: url('roboto_regular_macroman/Roboto-Regular-webfont.eot?#iefix') format('embedded-opentype'),
     url('roboto_regular_macroman/Roboto-Regular-webfont.woff') format('woff'),
     url('roboto_regular_macroman/Roboto-Regular-webfont.ttf') format('truetype'),
     url('roboto_regular_macroman/Roboto-Regular-webfont.svg#RobotoRegular') format('svg');
font-weight: normal;
font-style: normal;
}

watch for the path of the files, here i uploaded the folder called "roboto_regular_macroman" in the same folder where the css is

then you can now simply use the font by typing font-family: 'Roboto';

How do I link to Google Maps with a particular longitude and latitude?

This schema has changed again (23rd October 2018). See Kushagr's answer for the latest.

This for a map with the marker (via aaronm's comment):

https://www.google.com/maps/?q=-15.623037,18.388672

For an older example (no marker on this one):

https://www.google.com/maps/preview/@-15.623037,18.388672,8z

The oldest format:

http://maps.google.com/maps?ll=-15.623037,18.388672&spn=65.61535,79.013672

How to replace blank (null ) values with 0 for all records?

The following Query also works and you won't need an update query if that's what you'd prefer:

IIF(Column Is Null,0,Column)

Difference between `constexpr` and `const`

An overview of the const and constexpr keywords

In C ++, if a const object is initialized with a constant expression, we can use our const object wherever a constant expression is required.

const int x = 10;
int a[x] = {0};

For example, we can make a case statement in switch.

constexpr can be used with arrays.

constexpr is not a type.

The constexpr keyword can be used in conjunction with the auto keyword.

constexpr auto x = 10;

struct Data {   // We can make a bit field element of struct.   
    int a:x;
 };

If we initialize a const object with a constant expression, the expression generated by that const object is now a constant expression as well.

Constant Expression : An expression whose value can be calculated at compile time.

x*5-4 // This is a constant expression. For the compiler, there is no difference between typing this expression and typing 46 directly.

Initialize is mandatory. It can be used for reading purposes only. It cannot be changed. Up to this point, there is no difference between the "const" and "constexpr" keywords.

NOTE: We can use constexpr and const in the same declaration.

constexpr const int* p;

Constexpr Functions

Normally, the return value of a function is obtained at runtime. But calls to constexpr functions will be obtained as a constant in compile time when certain conditions are met.

NOTE : Arguments sent to the parameter variable of the function in function calls or to all parameter variables if there is more than one parameter, if C.E the return value of the function will be calculated in compile time. !!!

constexpr int square (int a){
return a*a;
}

constexpr int a = 3;
constexpr int b = 5;

int arr[square(a*b+20)] = {0}; //This expression is equal to int arr[35] = {0};

In order for a function to be a constexpr function, the return value type of the function and the type of the function's parameters must be in the type category called "literal type".

The constexpr functions are implicitly inline functions.

An important point :

None of the constexpr functions need to be called with a constant expression.It is not mandatory. If this happens, the computation will not be done at compile time. It will be treated like a normal function call. Therefore, where the constant expression is required, we will no longer be able to use this expression.

The conditions required to be a constexpr function are shown below;

1 ) The types used in the parameters of the function and the type of the return value of the function must be literal type.

2 ) A local variable with static life time should not be used inside the function.

3 ) If the function is legal, when we call this function with a constant expression in compile time, the compiler calculates the return value of the function in compile time.

4 ) The compiler needs to see the code of the function, so constexpr functions will almost always be in the header files.

5 ) In order for the function we created to be a constexpr function, the definition of the function must be in the header file.Thus, whichever source file includes that header file will see the function definition.

Bonus

Normally with Default Member Initialization, static data members with const and integral types can be initialized within the class. However, in order to do this, there must be both "const" and "integral types".

If we use static constexpr then it doesn't have to be an integral type to initialize it inside the class. As long as I initialize it with a constant expression, there is no problem.

class Myclass  {
         const static int sx = 15;         // OK
         constexpr static int sy = 15;     // OK
         const static double sd = 1.5;     // ERROR
         constexpr static double sd = 1.5; // OK
 };

What is the function __construct used for?

A constructor allows you to initialize an object's properties upon creation of the object.

If you create a __construct() function, PHP will automatically call this function when you create an object from a class.

https://www.w3schools.com/php/php_oop_constructor.asp

What does "Object reference not set to an instance of an object" mean?

It means you did something like this.

Class myObject = GetObjectFromFunction();

And without doing

if(myObject!=null), you go ahead do myObject.Method();

Equal height rows in CSS Grid Layout

The short answer is that setting grid-auto-rows: 1fr; on the grid container solves what was asked.

https://codepen.io/Hlsg/pen/EXKJba

How to flush output after each `echo` call?

I've gotten the same issue and one of the posted example in the manual worked. A character set must be specified as one of the posters here already mentioned. http://www.php.net/manual/en/function.ob-flush.php#109314

header( 'Content-type: text/html; charset=utf-8' );
echo 'Begin ...<br />';
for( $i = 0 ; $i < 10 ; $i++ )
{
    echo $i . '<br />';
    flush();
    ob_flush();
    sleep(1);
}
echo 'End ...<br />';

.toLowerCase not working, replacement function?

It is a number, not a string. Numbers don't have a toLowerCase() function because numbers do not have case in the first place.

To make the function run without error, run it on a string.

var ans = "334";

Of course, the output will be the same as the input since, as mentioned, numbers don't have case in the first place.

How to return history of validation loss in Keras

The dictionary with histories of "acc", "loss", etc. is available and saved in hist.history variable.

Change font color and background in html on mouseover

Either do it with CSS like the other answers did or change the text style color directly via the onMouseOver and onMouseOut event:

onmouseover="this.bgColor='white'; this.style.color='black'"

onmouseout="this.bgColor='black'; this.style.color='white'"

How to make an HTTP request + basic auth in Swift

//create authentication base 64 encoding string

    let PasswordString = "\(txtUserName.text):\(txtPassword.text)"
    let PasswordData = PasswordString.dataUsingEncoding(NSUTF8StringEncoding)
    let base64EncodedCredential = PasswordData!.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.Encoding64CharacterLineLength)
    //let base64EncodedCredential = PasswordData!.base64EncodedStringWithOptions(nil)

//create authentication url

    let urlPath: String = "http://...../auth"
    var url: NSURL = NSURL(string: urlPath)

//create and initialize basic authentication request

    var request: NSMutableURLRequest = NSMutableURLRequest(URL: url)
    request.setValue("Basic \(base64EncodedCredential)", forHTTPHeaderField: "Authorization")
    request.HTTPMethod = "GET"

//You can use one of below methods

//1 URL request with NSURLConnectionDataDelegate

    let queue:NSOperationQueue = NSOperationQueue()
    let urlConnection = NSURLConnection(request: request, delegate: self)
    urlConnection.start()

//2 URL Request with AsynchronousRequest

    NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue()) {(response, data, error) in
        println(NSString(data: data, encoding: NSUTF8StringEncoding))
    }

//2 URL Request with AsynchronousRequest with json output

    NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue(), completionHandler:{ (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void in
        var err: NSError
        var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
        println("\(jsonResult)")
    })

//3 URL Request with SynchronousRequest

    var response: AutoreleasingUnsafePointer<NSURLResponse?>=nil
    var dataVal: NSData =  NSURLConnection.sendSynchronousRequest(request, returningResponse: response, error:nil)
    var err: NSError
    var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataVal, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
    println("\(jsonResult)")

//4 URL Request with NSURLSession

    let config = NSURLSessionConfiguration.defaultSessionConfiguration()
    let authString = "Basic \(base64EncodedCredential)"
    config.HTTPAdditionalHeaders = ["Authorization" : authString]
    let session = NSURLSession(configuration: config)

    session.dataTaskWithURL(url) {
        (let data, let response, let error) in
        if let httpResponse = response as? NSHTTPURLResponse {
            let dataString = NSString(data: data, encoding: NSUTF8StringEncoding)
            println(dataString)
        }
    }.resume()

// you may be get fatal error if you changed the request.HTTPMethod = "POST" when server request GET request

ASP.NET Core configuration for .NET Core console application

You can use LiteWare.Configuration library for that. It is very similar to .NET Framework original ConfigurationManager and works for .NET Core/Standard. Code-wise, you'll end up with something like:

string cacheDirectory = ConfigurationManager.AppSettings.GetValue<string>("CacheDirectory");
ulong cacheFileSize = ConfigurationManager.AppSettings.GetValue<ulong>("CacheFileSize");

Disclaimer: I am the author of LiteWare.Configuration.

How to execute an .SQL script file using c#

Added additional improvements to surajits answer:

using System;
using Microsoft.SqlServer.Management.Smo;
using Microsoft.SqlServer.Management.Common;
using System.IO;
using System.Data.SqlClient;

namespace MyNamespace
{
    public partial class RunSqlScript : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            var connectionString = @"your-connection-string";
            var pathToScriptFile = Server.MapPath("~/sql-scripts/") + "sql-script.sql";
            var sqlScript = File.ReadAllText(pathToScriptFile);

            using (var connection = new SqlConnection(connectionString))
            {
                var server = new Server(new ServerConnection(connection));
                server.ConnectionContext.ExecuteNonQuery(sqlScript);
            }
        }
    }
}

Also, I had to add the following references to my project:

  • C:\Program Files\Microsoft SQL Server\120\SDK\Assemblies\Microsoft.SqlServer.ConnectionInfo.dll
  • C:\Program Files\Microsoft SQL Server\120\SDK\Assemblies\Microsoft.SqlServer.Smo.dll

I have no idea if those are the right dll:s to use since there are several folders in C:\Program Files\Microsoft SQL Server but in my application these two work.

How to make CREATE OR REPLACE VIEW work in SQL Server?

Altering a view could be accomplished by dropping the view and recreating it. Use the following to drop and recreate your view.

IF EXISTS
(SELECT NAME FROM SYS.VIEWS WHERE NAME = 'dbo.test_abc_def')
DROP VIEW dbo.test_abc_def) go

CREATE VIEW dbo.test_abc_def AS
SELECT 
    VCV.xxxx, 
    VCV.yyyy AS yyyy
    ,VCV.zzzz AS zzzz
FROM TABLE_A

How to get column by number in Pandas?

Another way is to select a column with the columns array:

In [5]: df = pd.DataFrame([[1,2], [3,4]], columns=['a', 'b'])

In [6]: df
Out[6]: 
   a  b
0  1  2
1  3  4

In [7]: df[df.columns[0]]
Out[7]: 
0    1
1    3
Name: a, dtype: int64

Where can I find my Facebook application id and secret key?

From 2018:

Go to Settings -> Basic -> App Secret (type your password and you're ready to go).

How are software license keys generated?

All of the CD only copy protection algorithms inconvience honest users while providing no protection against piracy whatsoever.

The "pirate" only need to have access to one legitimate cd and its access code, he can then make n copies and distribute them.

It does not matter how cryptographically secure you make the code, you need to supply this with the CD in plain text or an legitimate user cannot activite the software.

Most secure schemes involve either the user providing the software supplier with some details of the machine which will run the software (cpu serial numbers, mac addresses, Ip address etc.), or, require online access to register the software on the suppliers website and in return receive an activitation token. The first option requires a lot of manual administration and is only worth it for very high value software, the, second option can be spoofed and is absolutly infuriating if you have limited network access or you are stuck behind a firewall.

On the whole its much easier to establish a trust relationship with your customers!

MySQL - Meaning of "PRIMARY KEY", "UNIQUE KEY" and "KEY" when used together while creating a table

A key is just a normal index. A way over simplification is to think of it like a card catalog at a library. It points MySQL in the right direction.

A unique key is also used for improved searching speed, but it has the constraint that there can be no duplicated items (there are no two x and y where x is not y and x == y).

The manual explains it as follows:

A UNIQUE index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an existing row. This constraint does not apply to NULL values except for the BDB storage engine. For other engines, a UNIQUE index permits multiple NULL values for columns that can contain NULL. If you specify a prefix value for a column in a UNIQUE index, the column values must be unique within the prefix.

A primary key is a 'special' unique key. It basically is a unique key, except that it's used to identify something.

The manual explains how indexes are used in general: here.

In MSSQL, the concepts are similar. There are indexes, unique constraints and primary keys.

Untested, but I believe the MSSQL equivalent is:

CREATE TABLE tmp (
  id int NOT NULL PRIMARY KEY IDENTITY,
  uid varchar(255) NOT NULL CONSTRAINT uid_unique UNIQUE,
  name varchar(255) NOT NULL,
  tag int NOT NULL DEFAULT 0,
  description varchar(255),
);

CREATE INDEX idx_name ON tmp (name);
CREATE INDEX idx_tag ON tmp (tag);

Edit: the code above is tested to be correct; however, I suspect that there's a much better syntax for doing it. Been a while since I've used SQL server, and apparently I've forgotten quite a bit :).

EL access a map value by Integer key

If you just happen to have a Map with Integer keys you cannot change, you could write a custom EL function to convert a Long to Integer. This would allow you to do something like:

<c:out value="${map[myLib:longToInteger(1)]}"/>

How to clear cache in Yarn?

Run yarn cache clean.


Run yarn help cache in your bash, and you will see:

Usage: yarn cache [ls|clean] [flags]

Options: -h, --help output usage information -V, --version output the version number --offline
--prefer-offline
--strict-semver
--json
--global-folder [path]
--modules-folder [path] rather than installing modules into the node_modules folder relative to the cwd, output them here
--packages-root [path] rather than storing modules into a global packages root, store them here
--mutex [type][:specifier] use a mutex to ensure only one yarn instance is executing

Visit http://yarnpkg.com/en/docs/cli/cache for documentation about this command.

What is the id( ) function used for?

Be carefull (concerning the answer just below)...That's only true because 123 is between -5 and 256...

In [111]: q = 257                                                         

In [112]: id(q)                                                            
Out[112]: 140020248465168

In [113]: w = 257                                                         

In [114]: id(w)                                                           
Out[114]: 140020274622544

In [115]: id(257)                                                         
Out[115]: 140020274622768

Run a PostgreSQL .sql file using command line arguments

Use this to execute *.sql files when the PostgreSQL server is located in a difference place:

psql -h localhost -d userstoreis -U admin -p 5432 -a -q -f /home/jobs/Desktop/resources/postgresql.sql

-h PostgreSQL server IP address
-d database name
-U user name
-p port which PostgreSQL server is listening on
-f path to SQL script
-a all echo
-q quiet

Then you are prompted to enter the password of the user.

EDIT: updated based on the comment provided by @zwacky

The program can't start because libgcc_s_dw2-1.dll is missing

Find that dll on your PC, and copy it into the same directory your executable is in.

Why am I getting a "401 Unauthorized" error in Maven?

I got the same error when trying to deploy to a Artifactory repository, the following solved the issue for me:

Go to the repository setting in artifactory and enable the point "Force Maven Authentication" and the 401 "Unauthorized" error should be gone. (Of course you need to supply your credentials in the settings.xml file at best in plain text to prevent issues)

I guess by default, even through you supply the right credentials in the settings.xml file, they don't get used and you get the Unauthorized exception.

Reading a string with spaces with sscanf

If you want to scan to the end of the string (stripping out a newline if there), just use:

char *x = "19 cool kid";
sscanf (x, "%d %[^\n]", &age, buffer);

That's because %s only matches non-whitespace characters and will stop on the first whitespace it finds. The %[^\n] format specifier will match every character that's not (because of ^) in the selection given (which is a newline). In other words, it will match any other character.


Keep in mind that you should have allocated enough space in your buffer to take the string since you cannot be sure how much will be read (a good reason to stay away from scanf/fscanf unless you use specific field widths).

You could do that with:

char *x = "19 cool kid";
char *buffer = malloc (strlen (x) + 1);
sscanf (x, "%d %[^\n]", &age, buffer);

(you don't need * sizeof(char) since that's always 1 by definition).

Stop handler.postDelayed()

this may be old, but for those looking for answer you can use this...

public void stopHandler() {
   handler.removeMessages(0);
}

cheers

How can I read an input string of unknown length?

Take a character pointer to store required string.If you have some idea about possible size of string then use function

char *fgets (char *str, int size, FILE* file);`

else you can allocate memory on runtime too using malloc() function which dynamically provides requested memory.

HTTP redirect: 301 (permanent) vs. 302 (temporary)

Status 301 means that the resource (page) is moved permanently to a new location. The client/browser should not attempt to request the original location but use the new location from now on.

Status 302 means that the resource is temporarily located somewhere else, and the client/browser should continue requesting the original url.

pandas python how to count the number of records or rows in a dataframe

Simple method to get the records count:

df.count()[0]

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)

Using PHP to upload file and add the path to MySQL database

First you should use print_r($_FILES) to debug, and see what it contains. :

your uploads.php would look like:

//This is the directory where images will be saved
$target = "pics/";
$target = $target . basename( $_FILES['Filename']['name']);

//This gets all the other information from the form
$Filename=basename( $_FILES['Filename']['name']);
$Description=$_POST['Description'];


//Writes the Filename to the server
if(move_uploaded_file($_FILES['Filename']['tmp_name'], $target)) {
    //Tells you if its all ok
    echo "The file ". basename( $_FILES['Filename']['name']). " has been uploaded, and your information has been added to the directory";
    // Connects to your Database
    mysql_connect("localhost", "root", "") or die(mysql_error()) ;
    mysql_select_db("altabotanikk") or die(mysql_error()) ;

    //Writes the information to the database
    mysql_query("INSERT INTO picture (Filename,Description)
    VALUES ('$Filename', '$Description')") ;
} else {
    //Gives and error if its not
    echo "Sorry, there was a problem uploading your file.";
}



?>

EDIT: Since this is old post, currently it is strongly recommended to use either mysqli or pdo instead mysql_ functions in php

Detecting endianness programmatically in a C++ program

The C++ way has been to use boost, where preprocessor checks and casts are compartmentalized away inside very thoroughly-tested libraries.

The Predef Library (boost/predef.h) recognizes four different kinds of endianness.

The Endian Library was planned to be submitted to the C++ standard, and supports a wide variety of operations on endian-sensitive data.

As stated in answers above, Endianness will be a part of c++20.

How to solve static declaration follows non-static declaration in GCC C code?

This error can be caused by an unclosed set of brackets.

int main {
  doSomething {}
  doSomething else {
}

Not so easy to spot, even in this 4 line example.

This error, in a 150 line main function, caused the bewildering error: "static declaration of ‘savePair’ follows non-static declaration". There was nothing wrong with my definition of function savePair, it was that unclosed bracket.

Get button click inside UITableViewCell

I find it simplest to subclass the button inside your cell (Swift 3):

class MyCellInfoButton: UIButton {
    var indexPath: IndexPath?
}

In your cell class:

class MyCell: UICollectionViewCell {
    @IBOutlet weak var infoButton: MyCellInfoButton!
   ...
}

In the table view's or collection view's data source, when dequeueing the cell, give the button its index path:

cell.infoButton.indexPath = indexPath

So you can just put these code into your table view controller:

@IBAction func handleTapOnCellInfoButton(_ sender: MyCellInfoButton) {
        print(sender.indexPath!) // Do whatever you want with the index path!
}

And don't forget to set the button's class in your Interface Builder and link it to the handleTapOnCellInfoButton function!


edited:

Using dependency injection. To set up calling a closure:

class MyCell: UICollectionViewCell {
    var someFunction: (() -> Void)?
    ...
    @IBAction func didTapInfoButton() {
        someFunction?()
    }
}

and inject the closure in the willDisplay method of the collection view's delegate:

 func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    (cell as? MyCell)?.someFunction = {
        print(indexPath) // Do something with the indexPath.
    }
}

Assertion failure in dequeueReusableCellWithIdentifier:forIndexPath:

I give you the answer in both Objective C and Swift.Before that I want to say

If we use the dequeueReusableCellWithIdentifier:forIndexPath:,we must register a class or nib file using the registerNib:forCellReuseIdentifier: or registerClass:forCellReuseIdentifier: method before calling this method as Apple Documnetation Says

So we add registerNib:forCellReuseIdentifier: or registerClass:forCellReuseIdentifier:

Once we registered a class for the specified identifier and a new cell must be created, this method initializes the cell by calling its initWithStyle:reuseIdentifier: method. For nib-based cells, this method loads the cell object from the provided nib file. If an existing cell was available for reuse, this method calls the cell’s prepareForReuse method instead.

in viewDidLoad method we should register the cell

Objective C

OPTION 1:

[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"cell"];

OPTION 2:

[self.tableView registerNib:[UINib nibWithNibName:@"CustomCell" bundle:nil] forCellReuseIdentifier:@"cell"];

in above code nibWithNibName:@"CustomCell" give your nib name instead of my nib name CustomCell

SWIFT

OPTION 1:

tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")

OPTION 2:

tableView.registerNib(UINib(nibName: "NameInput", bundle: nil), forCellReuseIdentifier: "Cell") 

in above code nibName:"NameInput" give your nib name

Testing if value is a function

Make sure you are calling typeof on the actual function, not a string literal:

function x() { 
    console.log("hi"); 
}

typeof "x"; // returns "string"

typeof x; // returns "function"

How to switch to other branch in Source Tree to commit the code?

  1. Go to the log view (to be able to go here go to View -> log view).
  2. Double click on the line with the branch label stating that branch. Automatically, it will switch branch. (A prompt will dropdown and say switching branch.)
  3. If you have two or more branches on the same line, it will ask you via prompt which branch you want to switch. Choose the specific branch from the dropdown and click ok.

To determine which branch you are now on, look at the side bar, under BRANCHES, you are in the branch that is in BOLD LETTERS.

How to format numbers as currency string?

A function to handle currency output, including negatives.

Sample Output:
$5.23
-$5.23

function formatCurrency(total) {
    var neg = false;
    if(total < 0) {
        neg = true;
        total = Math.abs(total);
    }
    return (neg ? "-$" : '$') + parseFloat(total, 10).toFixed(2).replace(/(\d)(?=(\d{3})+\.)/g, "$1,").toString();
}

AES Encrypt and Decrypt

I found the solution, it is a good library.

Cross platform 256bit AES encryption / decryption.

This project contains the implementation of 256 bit AES encryption which works on all the platforms (C#, iOS, Android). One of the key objective is to make AES work on all the platforms with simple implementation.

Platforms Supported: iOS , Android , Windows (C#).

https://github.com/Pakhee/Cross-platform-AES-encryption

Array vs ArrayList in performance

It is pretty obvious that array[10] is faster than array.get(10), as the later internally does the same call, but adds the overhead for the function call plus additional checks.

Modern JITs however will optimize this to a degree, that you rarely have to worry about this, unless you have a very performance critical application and this has been measured to be your bottleneck.

Creating a list of dictionaries results in a list of copies of the same dictionary

info is a pointer to a dictionary - you keep adding the same pointer to your list contact.

Insert info = {} into the loop and it should solve the problem:

...
content = []
for iframe in soup.find_all('iframe'):
    info = {}
    info['src'] = iframe.get('src')
    info['height'] = iframe.get('height')
    info['width'] = iframe.get('width')
...

Node.js throws "btoa is not defined" error

I have a code shared between server and client and I needed an implementation of btoa inside it. I tried doing something like:

const btoaImplementation =  btoa || (str => Buffer.from(str).toString('base64'));

but the Server would crush with:

ReferenceError: btoa is not defined

while Buffer is not defined on the client.

I couldn't check window.btoa (it's a shared code, remember?)

So I ended up with this implementation:

const btoaImplementation = str => {
    try {
        return btoa(str);
    } catch(err) {
        return Buffer.from(str).toString('base64')
    }
};

Capturing multiple line output into a Bash variable

Parsing multiple output

Introduction

So your myscript output 3 lines, could look like:

myscript() { echo $'abc\ndef\nghi'; }

or

myscript() { local i; for i in abc def ghi ;do echo $i; done ;}

Ok this is a function, not a script (no need of path ./), but output is same

myscript
abc
def
ghi

Considering result code

To check for result code, test function will become:

myscript() { local i;for i in abc def ghi ;do echo $i;done;return $((RANDOM%128));}

1. Storing multiple output in one single variable, showing newlines

Your operation is correct:

RESULT=$(myscript)

About result code, you could add:

RCODE=$?

even in same line:

RESULT=$(myscript) RCODE=$?

Then

echo $RESULT 
abc def ghi

echo "$RESULT"
abc
def
ghi

echo ${RESULT@Q}
$'abc\ndef\nghi'

printf "%q\n" "$RESULT"
$'abc\ndef\nghi'

but for showing variable definition, use declare -p:

declare -p RESULT
declare -- RESULT="abc
def
ghi"

2. Parsing multiple output in array, using mapfile

Storing answer into myvar variable:

mapfile -t myvar < <(myscript)
echo ${myvar[2]}
ghi

Showing $myvar:

declare -p myvar
declare -a myvar=([0]="abc" [1]="def" [2]="ghi")

Considering result code

In case you have to check for result code, you could:

RESULT=$(myscript) RCODE=$?
mapfile -t myvar <<<"$RESULT"

3. Parsing multiple output by consecutives read in command group

{ read firstline; read secondline; read thirdline;} < <(myscript)
echo $secondline
def

Showing variables:

declare -p firstline secondline thirdline
declare -- firstline="abc"
declare -- secondline="def"
declare -- thirdline="ghi"

I often use:

{ read foo;read foo total use free foo ;} < <(df -k /)

Then

declare -p use free total
declare -- use="843476"
declare -- free="582128"
declare -- total="1515376"

Considering result code

Same prepended step:

RESULT=$(myscript) RCODE=$?
{ read firstline; read secondline; read thirdline;} <<<"$RESULT"

declare -p firstline secondline thirdline RCODE
declare -- firstline="abc"
declare -- secondline="def"
declare -- thirdline="ghi"
declare -- RCODE="50"

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

TextView txtvw = (TextView)findViewById(R.id.TextView01);
        txtvw.setText(readTxt());

 private String readTxt()
    {
    InputStream raw = getResources().openRawResource(R.raw.hello);

    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

    int i;
    try
    {
        i = raw.read();
        while (i != -1)
        {
            byteArrayOutputStream.write(i);
            i = raw.read();
        }
        raw.close();
    }
    catch (IOException e)
    {
        // TODO Auto-generated catch block

        e.printStackTrace();
    }


    return byteArrayOutputStream.toString();

}

TextView01:: txtview in linearlayout hello:: .txt file in res/raw folder (u can access ny othr folder as wel)

Ist 2 lines are 2 written in onCreate() method

rest is to be written in class extending Activity!!

Assigning multiple styles on an HTML element

You needed to do it like this:

_x000D_
_x000D_
<h2 style="text-align: center;font-family: Tahoma">TITLE</h2>
_x000D_
_x000D_
_x000D_

Hope it helped.

Spring JUnit: How to Mock autowired component in autowired component

You could use Mockito. I am not sure with PostConstruct specifically, but this generally works:

// Create a mock of Resource to change its behaviour for testing
@Mock
private Resource resource;

// Testing instance, mocked `resource` should be injected here 
@InjectMocks
@Resource
private TestedClass testedClass;

@Before
public void setUp() throws Exception {
    // Initialize mocks created above
    MockitoAnnotations.initMocks(this);
    // Change behaviour of `resource`
    when(resource.getSomething()).thenReturn("Foo");   
}

Send and receive messages through NSNotificationCenter in Objective-C?

There is also the possibility of using blocks:

NSOperationQueue *mainQueue = [NSOperationQueue mainQueue];
[[NSNotificationCenter defaultCenter] 
     addObserverForName:@"notificationName" 
     object:nil
     queue:mainQueue
     usingBlock:^(NSNotification *notification)
     {
          NSLog(@"Notification received!");
          NSDictionary *userInfo = notification.userInfo;

          // ...
     }];

Apple's documentation

.htaccess rewrite subdomain to directory

I had the same problem, and found a detailed explanation in http://www.webmasterworld.com/apache/3163397.htm

My solution (the subdomains contents should be in a folder called sd_subdomain:

Options +FollowSymLinks -MultiViews

RewriteEngine On
RewriteBase /

RewriteCond %{HTTP_HOST} !^www\.
RewriteCond %{HTTP_HOST} subdomain\.domain\.com
RewriteCond $1 !^sd_
RewriteRule (.*) /sd_subdomain/$1 [L]

jQuery: checking if the value of a field is null (empty)

I would also trim the input field, cause a space could make it look like filled

if ($.trim($('#person_data[document_type]').val()) != '')
{

}

justify-content property isn't working

justify-content only has an effect if there's space left over after your flex items have flexed to absorb the free space. In most/many cases, there won't be any free space left, and indeed justify-content will do nothing.

Some examples where it would have an effect:

  • if your flex items are all inflexible (flex: none or flex: 0 0 auto), and smaller than the container.

  • if your flex items are flexible, BUT can't grow to absorb all the free space, due to a max-width on each of the flexible items.

In both of those cases, justify-content would be in charge of distributing the excess space.

In your example, though, you have flex items that have flex: 1 or flex: 6 with no max-width limitation. Your flexible items will grow to absorb all of the free space, and there will be no space left for justify-content to do anything with.

Repeat string to certain length

This is pretty pythonic:

newstring = 'abc'*5
print newstring[0:6]

Can not find the tag library descriptor of springframework

  1. Download the Spring dependency jar
  2. Place it to the lib folder path is /WEB-INF/lib/spring.jar
  3. Then open the web.xml and the sample code is:

    <taglib>
      <taglib-uri>/WEB-INF/spring.tld</taglib-uri>
      <taglib-location>/WEB-INF/spring.tld</taglib-location>
    </taglib>
    
  4. Then the taglib is indicated where the jar file locates in ur system.

    <%@ taglib prefix="spring" uri="/WEB-INF/spring.tld" %>
    

How do you allow spaces to be entered using scanf?

Try

char str[11];
scanf("%10[0-9a-zA-Z ]", str);

Hope that helps.