Programs & Examples On #Xamdatagrid

Data grid control from Infragistics. Designed for WPF, can be used to produce reports, tables. Provides editing, sorting, filtering, grouping, and showing hierarchical data relationships

Flutter - Layout a Grid

A simple example loading images into the tiles.

import 'package:flutter/material.dart';

void main() {
  runApp( MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(

      color: Colors.white30,
      child: GridView.count(
          crossAxisCount: 4,
          childAspectRatio: 1.0,
          padding: const EdgeInsets.all(4.0),
          mainAxisSpacing: 4.0,
          crossAxisSpacing: 4.0,
          children: <String>[
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
          ].map((String url) {
            return GridTile(
                child: Image.network(url, fit: BoxFit.cover));
          }).toList()),
    );
  }
}

The Flutter Gallery app contains a real world example, which can be found here.

enter image description here

whitespaces in the path of windows filepath

path = r"C:\Users\mememe\Google Drive\Programs\Python\file.csv"

Closing the path in r"string" also solved this problem very well.

Vue - Deep watching an array of objects and calculating the change?

It is well defined behaviour. You cannot get the old value for a mutated object. That's because both the newVal and oldVal refer to the same object. Vue will not keep an old copy of an object that you mutated.

Had you replaced the object with another one, Vue would have provided you with correct references.

Read the Note section in the docs. (vm.$watch)

More on this here and here.

How to loop through an array containing objects and access their properties

Here's an example on how you can do it :)

_x000D_
_x000D_
var students = [{_x000D_
    name: "Mike",_x000D_
    track: "track-a",_x000D_
    achievements: 23,_x000D_
    points: 400,_x000D_
  },_x000D_
  {_x000D_
    name: "james",_x000D_
    track: "track-a",_x000D_
    achievements: 2,_x000D_
    points: 21,_x000D_
  },_x000D_
]_x000D_
_x000D_
students.forEach(myFunction);_x000D_
_x000D_
function myFunction(item, index) {_x000D_
  for (var key in item) {_x000D_
    console.log(item[key])_x000D_
  }_x000D_
}
_x000D_
_x000D_
_x000D_

How can I scale an entire web page with CSS?

For Cross-Browser Compatibility :

Example Goes Below :

<html><body class="entire-webpage"></body></html>



.entire-webpage{
        zoom: 2;
        -moz-transform: scale(2);/* Firefox Property */
        -moz-transform-origin: 0 0;
        -o-transform: scale(2);/* Opera Property */
        -o-transform-origin: 0 0;
        -webkit-transform: scale(2);/* Safari Property */
        -webkit-transform-origin: 0 0;
        transform: scale(2); /* Standard Property */
        transform-origin: 0 0;  /* Standard Property */
    }

How to retrieve Jenkins build parameters using the Groovy API?

Update: Jenkins 2.x solution:

With Jenkins 2 pipeline dsl, you can directly access any parameter with the trivial syntax based on the params (Map) built-in:

echo " FOOBAR value: ${params.'FOOBAR'}"

The returned value will be a String or a boolean depending on the Parameter type itself. The syntax is the same for scripted or declarative syntax. More info at: https://jenkins.io/doc/book/pipeline/jenkinsfile/#handling-parameters

Original Answer for Jenkins 1.x:

For Jenkins 1.x, the syntax is based on the build.buildVariableResolver built-ins:

// ... or if you want the parameter by name ...
def hardcoded_param = "FOOBAR"
def resolver = build.buildVariableResolver
def hardcoded_param_value = resolver.resolve(hardcoded_param)

Please note the official Jenkins Wiki page covers this in more details as well, especially how to iterate upon the build parameters: https://wiki.jenkins-ci.org/display/JENKINS/Parameterized+System+Groovy+script

The salient part is reproduced below:

// get parameters
def parameters = build?.actions.find{ it instanceof ParametersAction }?.parameters
parameters.each {
   println "parameter ${it.name}:"
   println it.dump()
}

I can't delete a remote master branch on git

The quickest way is to switch default branch from master to another and you can remove master branch from the web interface.

How to apply filters to *ngFor?

Simplified way (Used only on small arrays because of performance issues. In large arrays you have to make the filter manually via code):

See: https://angular.io/guide/pipes#appendix-no-filterpipe-or-orderbypipe

@Pipe({
    name: 'filter'
})
@Injectable()
export class FilterPipe implements PipeTransform {
    transform(items: any[], field : string, value : string): any[] {  
      if (!items) return [];
      if (!value || value.length == 0) return items;
      return items.filter(it => 
      it[field].toLowerCase().indexOf(value.toLowerCase()) !=-1);
    }
}

Usage:

<li *ngFor="let it of its | filter : 'name' : 'value or variable'">{{it}}</li>

If you use a variable as a second argument, don't use quotes.

css label width not taking effect

Use display: inline-block;

Explanation:

The label is an inline element, meaning it is only as big as it needs to be.

Set the display property to either inline-block or block in order for the width property to take effect.

Example:

_x000D_
_x000D_
#report-upload-form {_x000D_
    background-color: #316091;_x000D_
    color: #ddeff1;_x000D_
    font-weight: bold;_x000D_
    margin: 23px auto 0 auto;_x000D_
    border-radius: 10px;_x000D_
    width: 650px;_x000D_
    box-shadow: 0 0 2px 2px #d9d9d9;_x000D_
_x000D_
}_x000D_
_x000D_
#report-upload-form label {_x000D_
    padding-left: 26px;_x000D_
    width: 125px;_x000D_
    text-transform: uppercase;_x000D_
    display: inline-block;_x000D_
}_x000D_
_x000D_
#report-upload-form input[type=text], _x000D_
#report-upload-form input[type=file],_x000D_
#report-upload-form textarea {_x000D_
    width: 305px;_x000D_
}
_x000D_
<form id="report-upload-form" method="POST" action="" enctype="multipart/form-data">_x000D_
    <p><label for="id_title">Title:</label> <input id="id_title" type="text" class="input-text" name="title"></p>_x000D_
    <p><label for="id_description">Description:</label> <textarea id="id_description" rows="10" cols="40" name="description"></textarea></p>_x000D_
    <p><label for="id_report">Upload Report:</label> <input id="id_report" type="file" class="input-file" name="report"></p>_x000D_
</form>
_x000D_
_x000D_
_x000D_

adb command for getting ip address assigned by operator

Try:

adb shell ip addr show rmnet0

It will return something like that:

3: rmnet0: <UP,LOWER_UP> mtu 1500 qdisc htb state UNKNOWN qlen 1000
    link/[530]
    inet 172.22.1.100/29 scope global rmnet0
    inet6 fc01:abab:cdcd:efe0:8099:af3f:2af2:8bc/64 scope global dynamic
       valid_lft forever preferred_lft forever
    inet6 fe80::8099:af3f:2af2:8bc/64 scope link
       valid_lft forever preferred_lft forever 

This part is your IPV4 assigned by the operator

inet 172.22.1.100

This part is your IPV6 assigned by the operator

inet6 fc01:abab:cdcd:efe0:8099:af3f:2af2:8bc

.net Core 2.0 - Package was restored using .NetFramework 4.6.1 instead of target framework .netCore 2.0. The package may not be fully compatible

That particular package does not include assemblies for dotnet core, at least not at present. You may be able to build it for core yourself with a few tweaks to the project file, but I can't say for sure without diving into the source myself.

Connecting to Oracle Database through C#?

First off you need to download and install ODP from this site http://www.oracle.com/technetwork/topics/dotnet/index-085163.html

After installation add a reference of the assembly Oracle.DataAccess.dll.

Your are good to go after this.

using System; 
using Oracle.DataAccess.Client; 

class OraTest
{ 
    OracleConnection con; 
    void Connect() 
    { 
        con = new OracleConnection(); 
        con.ConnectionString = "User Id=<username>;Password=<password>;Data Source=<datasource>"; 
        con.Open(); 
        Console.WriteLine("Connected to Oracle" + con.ServerVersion); 
    }

    void Close() 
    {
        con.Close(); 
        con.Dispose(); 
    } 

    static void Main() 
    { 
        OraTest ot= new OraTest(); 
        ot.Connect(); 
        ot.Close(); 
    } 
}

Is there a good reason I see VARCHAR(255) used so often (as opposed to another length)?

Probably because both SQL Server and Sybase (to name two I am familiar with) used to have a 255 character maximum in the number of characters in a VARCHAR column. For SQL Server, this changed in version 7 in 1996/1997 or so... but old habits sometimes die hard.

How to hide console window in python?

Simply save it with a .pyw extension. This will prevent the console window from opening.

On Windows systems, there is no notion of an “executable mode”. The Python installer automatically associates .py files with python.exe so that a double-click on a Python file will run it as a script. The extension can also be .pyw, in that case, the console window that normally appears is suppressed.

Explanation at the bottom of section 2.2.2

Disallow Twitter Bootstrap modal window from closing

Kind of like @AymKdn's answer, but this will allow you to change the options without re-initializing the modal.

$('#myModal').data('modal').options.keyboard = false;

Or if you need to do multiple options, JavaScript's with comes in handy here!

with ($('#myModal').data("modal").options) {
    backdrop = 'static';
    keyboard = false;
}

If the modal is already open, these options will only take effect the next time the modal is opened.

Convert a String to int?

Well, no. Why there should be? Just discard the string if you don't need it anymore.

&str is more useful than String when you need to only read a string, because it is only a view into the original piece of data, not its owner. You can pass it around more easily than String, and it is copyable, so it is not consumed by the invoked methods. In this regard it is more general: if you have a String, you can pass it to where an &str is expected, but if you have &str, you can only pass it to functions expecting String if you make a new allocation.

You can find more on the differences between these two and when to use them in the official strings guide.

Private Variables and Methods in Python

Double underscore. That mangles the name. The variable can still be accessed, but it's generally a bad idea to do so.

Use single underscores for semi-private (tells python developers "only change this if you absolutely must") and doubles for fully private.

How to do a LIKE query with linq?

String [] obj = (from c in db.Contacts
                           where c.FirstName.StartsWith(prefixText)
                           select c.FirstName).ToArray();
            return obj;

StartsWith() and EndsWith() can help you a lot here. If you want to find data in between the field, then Contains() can be used.

Check if date is in the past Javascript

function isPrevDate() {
    alert("startDate is " + Startdate);
    if(Startdate.length != 0 && Startdate !='') {
        var start_date = Startdate.split('-');
        alert("Input date: "+ start_date);
        start_date=start_date[1]+"/"+start_date[2]+"/"+start_date[0];
        alert("start date arrray format " + start_date);
        var a = new Date(start_date);
        //alert("The date is a" +a);
        var today = new Date();
        var day = today.getDate();
        var mon = today.getMonth()+1;
        var year = today.getFullYear();
        today = (mon+"/"+day+"/"+year);
        //alert(today);
        var today = new Date(today);
        alert("Today: "+today.getTime());
        alert("a : "+a.getTime());
        if(today.getTime() > a.getTime() )
        {
            alert("Please select Start date in range");
            return false;
        } else {
            return true;
        }
    }
}

Change navbar color in Twitter Bootstrap

Using Less

You could also consider to compile your own version. Try http://getbootstrap.com/customize/ (which has a apart section for the Navbars settings (Default navbar and Inverted Navbar)) or download your own copy from https://github.com/twbs/bootstrap.

You will find the navbar settings in variables.less. navbar.less is used to compile the navbar (depends on variables.less and mixins.less).

Copy the 'navbar-default section' and fill in your own color settings. Changing the variables in variables.less will be the easiest way (changing the default or inverse navbar won't be a problem because you have one navbar per page only).

You won't change all settings in most cases:

// Navbar
// -------------------------

// Basics of a navbar
@navbar-height:                    50px;
@navbar-margin-bottom:             @line-height-computed;
@navbar-default-color:             #777;
@navbar-default-bg:                #f8f8f8;
@navbar-default-border:            darken(@navbar-default-bg, 6.5%);
@navbar-border-radius:             @border-radius-base;
@navbar-padding-horizontal:        floor(@grid-gutter-width / 2);
@navbar-padding-vertical:          ((@navbar-height - @line-height-computed) / 2);

// Navbar links
@navbar-default-link-color:                #777;
@navbar-default-link-hover-color:          #333;
@navbar-default-link-hover-bg:             transparent;
@navbar-default-link-active-color:         #555;
@navbar-default-link-active-bg:            darken(@navbar-default-bg, 6.5%);
@navbar-default-link-disabled-color:       #ccc;
@navbar-default-link-disabled-bg:          transparent;

// Navbar brand label
@navbar-default-brand-color:               @navbar-default-link-color;
@navbar-default-brand-hover-color:         darken(@navbar-default-link-color, 10%);
@navbar-default-brand-hover-bg:            transparent;

// Navbar toggle
@navbar-default-toggle-hover-bg:           #ddd;
@navbar-default-toggle-icon-bar-bg:        #ccc;
@navbar-default-toggle-border-color:       #ddd;

You could also try http://twitterbootstrap3navbars.w3masters.nl/. This tool generates CSS code for your custom navbar. Optionally, you could also add gradient colors and borders to the navbar.

How to extract IP Address in Spring MVC Controller get call?

You can get the IP address statically from the RequestContextHolder as below :

HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes())
        .getRequest();

String ip = request.getRemoteAddr();

SQL Server function to return minimum date (January 1, 1753)

You could write a User Defined Function that returns the min date value like this:

select cast(-53690 as datetime)

Then use that function in your scripts, and if you ever need to change it, there is only one place to do that.

Alternately, you could use this query if you prefer it for better readability:

select cast('1753-1-1' as datetime)

Example Function

create function dbo.DateTimeMinValue()
returns datetime as
begin
    return (select cast(-53690 as datetime))
end

Usage

select dbo.DateTimeMinValue() as DateTimeMinValue

DateTimeMinValue
-----------------------
1753-01-01 00:00:00.000

What is the difference between Select and Project Operations

Project will effects Columns in the table while Select effects the Rows. on other hand Project is use to select the columns with specefic properties rather than Select the all of columns data

How do I use a Boolean in Python?

Yes, there is a bool data type (which inherits from int and has only two values: True and False).

But also Python has the boolean-able concept for every object, which is used when function bool([x]) is called.

See more: object.nonzero and boolean-value-of-objects-in-python.

Ways to insert javascript into URL?

Javascript in URL will not be executed, on its own. That by no way means its safe or to be trusted.

A URL is another user input not to be trusted, GET or POST (or any other method for that matter) can cause allot of severe vulnerabilities.

A common example was/is the use of the PHP_SELF, REQUEST_URI, SCRIPT_NAME and similar variables. Developers would mistakenly echo them directly to the browser which led to the script being injected into the page and executed.

I would suggest you start to do allot of reading, these are some good places to start:

OWASP

XSS Cheat Sheet

XSS Prevention Cheat Sheet

Also google around for XSS (cross site scripting), XSRF (Cross Site Request Forgery), and SQL Injection. That will get you started, but it is allot of information to absorb so take your time. It will be worth it in the long run.

How can I use nohup to run process as a background process in linux?

You can write a script and then use nohup ./yourscript & to execute

For example:

vi yourscript

put

#!/bin/bash
script here

you may also need to change permission to run script on server

chmod u+rwx yourscript

finally

nohup ./yourscript &

set date in input type date

document.getElementById("datePicker").valueAsDate = new Date()

should work.

php get values from json encode

json_decode() will return an object or array if second value it's true:

$json = '{"countryId":"84","productId":"1","status":"0","opId":"134"}';
$json = json_decode($json, true);
echo $json['countryId'];
echo $json['productId'];
echo $json['status'];
echo $json['opId'];

Convert comma separated string to array in PL/SQL

TYPE string_aa IS TABLE OF VARCHAR2(32767) INDEX BY PLS_INTEGER;

FUNCTION string_to_list(p_string_in IN VARCHAR2)
    RETURN string_aa
    IS
      TYPE ref_cursor IS ref cursor;
      l_cur    ref_cursor;
      l_strlist string_aa;
      l_x      PLS_INTEGER;
    BEGIN      
      IF p_string_in IS NOT NULL THEN 
         OPEN l_cur FOR 
            SELECT regexp_substr(p_string_in,'[^,]+', 1, level) FROM dual
            CONNECT BY regexp_substr(p_string_in, '[^,]+', 1, level) IS NOT NULL;      
         l_x := 1; 
         LOOP
           FETCH l_cur INTO l_strlist(l_x);
           EXIT WHEN l_cur%notfound;
           -- excludes NULL items  e.g.   1,2,,,,5,6,7
           l_x := l_x + 1;
         END LOOP;
      END IF;   
      RETURN l_strlist;
   END string_to_list;

How to browse for a file in java swing library?

I ended up using this quick piece of code that did exactly what I needed:

final JFileChooser fc = new JFileChooser();
fc.showOpenDialog(this);

try {
    // Open an input stream
    Scanner reader = new Scanner(fc.getSelectedFile());
}

stop all instances of node.js server

Use the following command to kill and restart node server from batch file

    @echo off
cd "D:\sam\Projects\Node"
taskkill /IM node.exe -F
start /min cmd /C "node index.js"
goto :EOF

ComboBox: Adding Text and Value to an Item (no Binding Source)

You can use this code to insert some items into a combo box with text and value.

C#

private void ComboBox_SelectionChanged_1(object sender, SelectionChangedEventArgs e)
{
    combox.Items.Insert(0, "Copenhagen");
    combox.Items.Insert(1, "Tokyo");
    combox.Items.Insert(2, "Japan");
    combox.Items.Insert(0, "India");   
}

XAML

<ComboBox x:Name="combox" SelectionChanged="ComboBox_SelectionChanged_1"/>

How can I serve static html from spring boot?

You can quickly serve static content in JAVA Spring-boot App via thymeleaf (ref: source)

I assume you have already added Spring Boot plugin apply plugin: 'org.springframework.boot' and the necessary buildscript

Then go ahead and ADD thymeleaf to your build.gradle ==>

dependencies {
    compile('org.springframework.boot:spring-boot-starter-web')
    compile("org.springframework.boot:spring-boot-starter-thymeleaf")
    testCompile('org.springframework.boot:spring-boot-starter-test')
}

Lets assume you have added home.html at src/main/resources To serve this file, you will need to create a controller.

package com.ajinkya.th.controller;

  import org.springframework.stereotype.Controller;
  import org.springframework.web.bind.annotation.RequestMapping;

  @Controller
  public class HomePageController {

      @RequestMapping("/")
      public String homePage() {
        return "home";
      }

  }

Thats it ! Now restart your gradle server. ./gradlew bootRun

Adding a stylesheet to asp.net (using Visual Studio 2010)

Add your style here:

<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Site.master.cs" Inherits="BSC.SiteMaster" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head runat="server">
    <title></title>
    <link href="~/Styles/Site.css" rel="stylesheet" type="text/css" />
    <link href="~/Styles/NewStyle.css" rel="stylesheet" type="text/css" />

    <asp:ContentPlaceHolder ID="HeadContent" runat="server">
    </asp:ContentPlaceHolder>
</head>

Then in the page:

<asp:Table CssClass=NewStyleExampleClass runat="server" >

Printing object properties in Powershell

# Json to object
$obj = $obj | ConvertFrom-Json
Write-host $obj.PropertyName

Multiple INSERT statements vs. single INSERT with multiple VALUES

It is not too surprising: the execution plan for the tiny insert is computed once, and then reused 1000 times. Parsing and preparing the plan is quick, because it has only four values to del with. A 1000-row plan, on the other hand, needs to deal with 4000 values (or 4000 parameters if you parameterized your C# tests). This could easily eat up the time savings you gain by eliminating 999 roundtrips to SQL Server, especially if your network is not overly slow.

Entity Framework: There is already an open DataReader associated with this Command

Alternatively to using MARS (MultipleActiveResultSets) you can write your code so you dont open multiple result sets.

What you can do is to retrieve the data to memory, that way you will not have the reader open. It is often caused by iterating through a resultset while trying to open another result set.

Sample Code:

public class MyContext : DbContext
{
    public DbSet<Blog> Blogs { get; set; }
    public DbSet<Post> Posts { get; set; }
}

public class Blog
{
    public int BlogID { get; set; }
    public virtual ICollection<Post> Posts { get; set; }
}

public class Post
{
    public int PostID { get; set; }
    public virtual Blog Blog { get; set; }
    public string Text { get; set; }
}

Lets say you are doing a lookup in your database containing these:

var context = new MyContext();

//here we have one resultset
var largeBlogs = context.Blogs.Where(b => b.Posts.Count > 5); 

foreach (var blog in largeBlogs) //we use the result set here
{
     //here we try to get another result set while we are still reading the above set.
    var postsWithImportantText = blog.Posts.Where(p=>p.Text.Contains("Important Text"));
}

We can do a simple solution to this by adding .ToList() like this:

var largeBlogs = context.Blogs.Where(b => b.Posts.Count > 5).ToList();

This forces entityframework to load the list into memory, thus when we iterate though it in the foreach loop it is no longer using the data reader to open the list, it is instead in memory.

I realize that this might not be desired if you want to lazyload some properties for example. This is mostly an example that hopefully explains how/why you might get this problem, so you can make decisions accordingly

Styles.Render in MVC4

Polo I wouldn't use Bundles in MVC for multiple reasons. It doesn't work in your case because you have to set up a custom BundleConfig class in your Apps_Start folder. This makes no sense when you can simple add a style in the head of your html like so:

<link rel="stylesheet" href="~/Content/bootstrap.css" />
<link rel="stylesheet" href="~/Content/bootstrap.theme.css" />

You can also add these to a Layout.cshtml or partial class that's called from all your views and dropped into each page. If your styles change, you can easily change the name and path without having to recompile.

Adding hard-coded links to CSS in a class breaks with the whole purpose of separation of the UI and design from the application model, as well. You also don't want hard coded style sheet paths managed in c# because you can no longer build "skins" or separate style models for say different devices, themes, etc. like so:

<link rel="stylesheet" href="~/UI/Skins/skin1/base.css" />
<link rel="stylesheet" href="~/UI/Skins/skin2/base.css" />

Using this system and Razor you can now switch out the Skin Path from a database or user setting and change the whole design of your website by just changing the path dynamically.

The whole purpose of CSS 15 years ago was to develop both user-controlled and application-controlled style sheet "skins" for sites so you could switch out the UI look and feel separate from the application and repurpose the content independent of the data structure.....for example a printable version, mobile, audio version, raw xml, etc.

By moving back now to this "old-fashioned", hard-coded path system using C# classes, rigid styles like Bootstrap, and merging the themes of sites with application code, we have gone backwards again to how websites were built in 1998.

Is there a way to create interfaces in ES6 / Node 4?

there are packages that can simulate interfaces .

you can use es6-interface

What is the Java equivalent of PHP var_dump?

You XML serialization, and you should get a very neat representation even of deeply nested objects.

Why does Java have an "unreachable statement" compiler error?

Because unreachable code is meaningless to the compiler. Whilst making code meaningful to people is both paramount and harder than making it meaningful to a compiler, the compiler is the essential consumer of code. The designers of Java take the viewpoint that code that is not meaningful to the compiler is an error. Their stance is that if you have some unreachable code, you have made a mistake that needs to be fixed.

There is a similar question here: Unreachable code: error or warning?, in which the author says "Personally I strongly feel it should be an error: if the programmer writes a piece of code, it should always be with the intention of actually running it in some scenario." Obviously the language designers of Java agree.

Whether unreachable code should prevent compilation is a question on which there will never be consensus. But this is why the Java designers did it.


A number of people in comments point out that there are many classes of unreachable code Java doesn't prevent compiling. If I understand the consequences of Gödel correctly, no compiler can possibly catch all classes of unreachable code.

Unit tests cannot catch every single bug. We don't use this as an argument against their value. Likewise a compiler can't catch all problematic code, but it is still valuable for it to prevent compilation of bad code when it can.

The Java language designers consider unreachable code an error. So preventing it compiling when possible is reasonable.


(Before you downvote: the question is not whether or not Java should have an unreachable statement compiler error. The question is why Java has an unreachable statement compiler error. Don't downvote me just because you think Java made the wrong design decision.)

How to get the full url in Express?

You need to construct it using req.headers.host + req.url. Of course if you are hosting in a different port and such you get the idea ;-)

Should C# or C++ be chosen for learning Games Programming (consoles)?

Its always a hard one to say because they were using assembly up until 1993, NBA Jam if anyone remembers that bad boy. Technology is constantly trending so its very difficult to say where it will go, I would recommend learning C and getting a very firm grasp on that then move onto C++. I will say this as a caution if you enjoy playing games you will not enjoy coding games.

How to use PDO to fetch results array in PHP?

$st = $data->prepare("SELECT * FROM exampleWHERE example LIKE :search LIMIT 10"); 

What's the use of ob_start() in php?

You have it backwards. ob_start does not buffer the headers, it buffers the content. Using ob_start allows you to keep the content in a server-side buffer until you are ready to display it.

This is commonly used to so that pages can send headers 'after' they've 'sent' some content already (ie, deciding to redirect half way through rendering a page).

Serializing/deserializing with memory stream

Use Method to Serialize and Deserialize Collection object from memory. This works on Collection Data Types. This Method will Serialize collection of any type to a byte stream. Create a Seperate Class SerilizeDeserialize and add following two methods:

public class SerilizeDeserialize
{

    // Serialize collection of any type to a byte stream

    public static byte[] Serialize<T>(T obj)
    {
        using (MemoryStream memStream = new MemoryStream())
        {
            BinaryFormatter binSerializer = new BinaryFormatter();
            binSerializer.Serialize(memStream, obj);
            return memStream.ToArray();
        }
    }

    // DSerialize collection of any type to a byte stream

    public static T Deserialize<T>(byte[] serializedObj)
    {
        T obj = default(T);
        using (MemoryStream memStream = new MemoryStream(serializedObj))
        {
            BinaryFormatter binSerializer = new BinaryFormatter();
            obj = (T)binSerializer.Deserialize(memStream);
        }
        return obj;
    }

}

How To use these method in your Class:

ArrayList arrayListMem = new ArrayList() { "One", "Two", "Three", "Four", "Five", "Six", "Seven" };
Console.WriteLine("Serializing to Memory : arrayListMem");
byte[] stream = SerilizeDeserialize.Serialize(arrayListMem);

ArrayList arrayListMemDes = new ArrayList();

arrayListMemDes = SerilizeDeserialize.Deserialize<ArrayList>(stream);

Console.WriteLine("DSerializing From Memory : arrayListMemDes");
foreach (var item in arrayListMemDes)
{
    Console.WriteLine(item);
}

Spring Data JPA - "No Property Found for Type" Exception

I ran into this same issue and found the solution here: https://dzone.com/articles/persistence-layer-spring-data

I had renamed an entity property. But with Springs Automatic Custom Queries there was an interface defined for the old property name.

public interface IFooDAO extends JpaRepository< Foo, Long >{
     Foo findByOldPropName( final String name );
}

The error indicated that it could no longer find "OldPropName" and threw the exception.

To quote the article on DZone:

When Spring Data creates a new Repository implementation, it analyzes all the methods defined by the interfaces and tries to automatically generate queries from the method name. While this has limitations, it is a very powerful and elegant way of defining new custom access methods with very little effort. For example, if the managed entity has a name field (and the Java Bean standard getter and setter for that field), defining the findByName method in the DAO interface will automatically generate the correct query:

public interface IFooDAO extends JpaRepository< Foo, Long >{
     Foo findByName( final String name );
}

This is a relatively simple example; a much larger set of keywords is supported by query creation mechanism.

In the case that the parser cannot match the property with the domain object field, the following exception is thrown:

java.lang.IllegalArgumentException: No property nam found for type class org.rest.model.Foo

Set margins in a LinearLayout programmatically

To add margins directly to items (some items allow direct editing of margins), you can do:

LayoutParams lp = ((ViewGroup) something).getLayoutParams();
if( lp instanceof MarginLayoutParams )
{
    ((MarginLayoutParams) lp).topMargin = ...;
    ((MarginLayoutParams) lp).leftMargin = ...;
    //... etc
}
else
    Log.e("MyApp", "Attempted to set the margins on a class that doesn't support margins: "+something.getClass().getName() );

...this works without needing to know about / edit the surrounding layout. Note the "instanceof" check in case you try and run this against something that doesn't support margins.

What is the difference between a "line feed" and a "carriage return"?

A line feed means moving one line forward. The code is \n.
A carriage return means moving the cursor to the beginning of the line. The code is \r.

Windows editors often still use the combination of both as \r\n in text files. Unix uses mostly only the \n.

The separation comes from typewriter times, when you turned the wheel to move the paper to change the line and moved the carriage to restart typing on the beginning of a line. This was two steps.

JavaScript: set dropdown selected item based on option text

var textToFind = 'Google';

var dd = document.getElementById('MyDropDown');
for (var i = 0; i < dd.options.length; i++) {
    if (dd.options[i].text === textToFind) {
        dd.selectedIndex = i;
        break;
    }
}

What is the meaning of the word logits in TensorFlow?

They are basically the fullest learned model you can get from the network, before it's been squashed down to apply to only the number of classes we are interested in. Check out how some researchers use them to train a shallow neural net based on what a deep network has learned: https://arxiv.org/pdf/1312.6184.pdf

It's kind of like how when learning a subject in detail, you will learn a great many minor points, but then when teaching a student, you will try to compress it to the simplest case. If the student now tried to teach, it'd be quite difficult, but would be able to describe it just well enough to use the language.

setting an environment variable in virtualenv

To activate virtualenv in env directory and export envinroment variables stored in .env use :

source env/bin/activate && set -a; source .env; set +a

PHP file_get_contents() and setting request headers

Actually, upon further reading on the file_get_contents() function:

// Create a stream
$opts = [
    "http" => [
        "method" => "GET",
        "header" => "Accept-language: en\r\n" .
            "Cookie: foo=bar\r\n"
    ]
];

// DOCS: https://www.php.net/manual/en/function.stream-context-create.php
$context = stream_context_create($opts);

// Open the file using the HTTP headers set above
// DOCS: https://www.php.net/manual/en/function.file-get-contents.php
$file = file_get_contents('http://www.example.com/', false, $context);

You may be able to follow this pattern to achieve what you are seeking to, I haven't personally tested this though. (and if it doesn't work, feel free to check out my other answer)

Comparing two arrays & get the values which are not common

PS > $c = Compare-Object -ReferenceObject (1..5) -DifferenceObject (1..6) -PassThru
PS > $c
6

Android Whatsapp/Chat Examples

Check out yowsup
https://github.com/tgalal/yowsup

Yowsup is a python library that allows you to do all the previous in your own app. Yowsup allows you to login and use the Whatsapp service and provides you with all capabilities of an official Whatsapp client, allowing you to create a full-fledged custom Whatsapp client.

A solid example of Yowsup's usage is Wazapp. Wazapp is full featured Whatsapp client that is being used by hundreds of thousands of people around the world. Yowsup is born out of the Wazapp project. Before becoming a separate project, it was only the engine powering Wazapp. Now that it matured enough, it was separated into a separate project, allowing anyone to build their own Whatsapp client on top of it. Having such a popular client as Wazapp, built on Yowsup, helped bring the project into a much advanced, stable and mature level, and ensures its continuous development and maintaince.

Yowsup also comes with a cross platform command-line frontend called yowsup-cli. yowsup-cli allows you to jump into connecting and using Whatsapp service directly from command line.

How do I update a formula with Homebrew?

I think the correct way to do is

brew upgrade mongodb

It will upgrade the mongodb formula. If you want to upgrade all outdated formula, simply

brew upgrade

How can strings be concatenated?

To concatenate strings in python you use the "+" sign

ref: http://www.gidnetwork.com/b-40.html

How to do a Jquery Callback after form submit?

I do not believe there is a callback-function like the one you describe.

What is normal here is to do the alterations using some server-side language, like PHP.

In PHP you could for instance fetch a hidden field from your form and do some changes if it is present.

PHP:

  $someHiddenVar = $_POST["hidden_field"];
    if (!empty($someHiddenVar)) {
        // do something 
    }

One way to go about it in Jquery is to use Ajax. You could listen to submit, return false to cancel its default behaviour and use jQuery.post() instead. jQuery.post has a success-callback.

$.post("test.php", $("#testform").serialize(), function(data) {
  $('.result').html(data);
});

http://api.jquery.com/jQuery.post/

Android: ListView elements with multiple clickable buttons

Probably you've found how to do it, but you can call

ListView.setItemsCanFocus(true)

and now your buttons will catch focus

codeigniter, result() vs. result_array()

result() is recursive in that it returns an std class object where as result_array() just returns a pure array, so result_array() would be choice regarding performance. There is very little difference in speed though.

Cannot push to Git repository on Bitbucket

Just try

git remote add origin <HTTP URL>

Trying to use INNER JOIN and GROUP BY SQL with SUM Function, Not Working

Use subquery

SELECT * FROM RES_DATA inner join (SELECT [CUSTOMER ID], sum([TOTAL AMOUNT]) FROM INV_DATA group by [CUSTOMER ID]) T on RES_DATA.[CUSTOMER ID] = t.[CUSTOMER ID]

Defining and using a variable in batch file

Consider also using SETX - it will set variable on user or machine (available for all users) level though the variable will be usable with the next opening of the cmd.exe ,so often it can be used together with SET :

::setting variable for the current user
if not defined My_Var (
  set "My_Var=My_Value"
  setx My_Var My_Value
)

::setting machine defined variable
if not defined Global_Var (
  set "Global_Var=Global_Value"
  SetX Global_Var Global_Value /m
)

You can also edit directly the registry values:

User Variables: HKEY_CURRENT_USER\Environment

System Variables: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment

Which will allow to avoid some restrictions of SET and SETX like the variables containing = in their names.

Java division by zero doesnt throw an ArithmeticException - why?

IEEE 754 defines 1.0 / 0.0 as Infinity and -1.0 / 0.0 as -Infinity and 0.0 / 0.0 as NaN.

By the way, floating point values also have -0.0 and so 1.0/ -0.0 is -Infinity.

Integer arithmetic doesn't have any of these values and throws an Exception instead.

To check for all possible values (e.g. NaN, 0.0, -0.0) which could produce a non finite number you can do the following.

if (Math.abs(tab[i] = 1 / tab[i]) < Double.POSITIVE_INFINITY)
   throw new ArithmeticException("Not finite");

how to enable sqlite3 for php?

For PHP7, use

sudo apt-get install php7.0-sqlite3

and restart Apache

sudo apache2ctl restart

ActiveModel::ForbiddenAttributesError when creating new user

For those using CanCanCan:

You will get this error if CanCanCan cannot find the correct params method.

For the :create action, CanCan will try to initialize a new instance with sanitized input by seeing if your controller will respond to the following methods (in order):

  1. create_params
  2. <model_name>_params such as article_params (this is the default convention in rails for naming your param method)
  3. resource_params (a generically named method you could specify in each controller)

Additionally, load_and_authorize_resource can now take a param_method option to specify a custom method in the controller to run to sanitize input.

You can associate the param_method option with a symbol corresponding to the name of a method that will get called:

class ArticlesController < ApplicationController
  load_and_authorize_resource param_method: :my_sanitizer

  def create
    if @article.save
      # hurray
    else
      render :new
    end
  end

  private

  def my_sanitizer
    params.require(:article).permit(:name)
  end
end

source: https://github.com/CanCanCommunity/cancancan#33-strong-parameters

android layout with visibility GONE

Done by having it like that:

view = inflater.inflate(R.layout.entry_detail, container, false);
TextView tp1= (TextView) view.findViewById(R.id.tp1);
LinearLayout layone= (LinearLayout) view.findViewById(R.id.layone);
tp1.setVisibility(View.VISIBLE);
layone.setVisibility(View.VISIBLE);

Finding smallest value in an array most efficiently

If you're developing some kind of your own array abstraction, you can get O(1) if you store smallest added value in additional attribute and compare it every time a new item is put into array.

It should look something like this:

class MyArray
{
public:
    MyArray() : m_minValue(INT_MAX) {}

    void add(int newValue)
    {
        if (newValue < m_minValue) m_minValue = newValue;
        list.push_back( newValue );
    }

    int min()
    {
        return m_minValue;
    }

private:
    int m_minValue;
    std::list m_list;
}

XAMPP, Apache - Error: Apache shutdown unexpectedly

Best Solution for windows user is :

  1. Open netstat (from XAMPP CONTROL PANEL)
  2. Find PID of process which uses port 80.
  3. Open CMD with Administrative.
  4. Run taskkill /pid PID (instead PID use pid u found from netstat)
    Heyy enjoy u Done.....

Converting a vector<int> to string

template<typename T>
string str(T begin, T end)
{
    stringstream ss;
    bool first = true;
    for (; begin != end; begin++)
    {
        if (!first)
            ss << ", ";
        ss << *begin;
        first = false;
    }
    return ss.str();
}

This is the str function that can make integers turn into a string and not into a char for what the integer represents. Also works for doubles.

Twitter bootstrap remote modal shows same content every time

I wrote a simple snippet handling the refreshing of the modal. Basically it stores the clicked link in the modal's data and check if it's the same link that has been clicked, removing or not the modal data.

var handleModal = function()
{
    $('.triggeringLink').click(function(event) {
        var $logsModal = $('#logsModal');
        var $triggeringLink = $logsModal.data('triggeringLink');

        event.preventDefault();

        if ($logsModal.data('modal') != undefined
            && $triggeringLink != undefined
            && !$triggeringLink.is($(this))
        ) {
            $logsModal.removeData('modal');
        }

        $logsModal.data('triggeringLink', $(this));

        $logsModal.modal({ remote: $(this).attr('href') });
        $logsModal.modal('show');
    });
};

Converting date between DD/MM/YYYY and YYYY-MM-DD?

Your example code is wrong. This works:

import datetime

datetime.datetime.strptime("21/12/2008", "%d/%m/%Y").strftime("%Y-%m-%d")

The call to strptime() parses the first argument according to the format specified in the second, so those two need to match. Then you can call strftime() to format the result into the desired final format.

How to test an SQL Update statement before running it?

One more option is to ask MySQL for the query plan. This tells you two things:

  • Whether there are any syntax errors in the query, if so the query plan command itself will fail
  • How MySQL is planning to execute the query, e.g. what indexes it will use

In MySQL and most SQL databases the query plan command is describe, so you would do:

describe update ...;

currently unable to handle this request HTTP ERROR 500

Have you included the statement include ("fileName.php"); ?

Are you sure that file is in the correct directory?

What's the difference between interface and @interface in java?

interface:

In general, an interface exposes a contract without exposing the underlying implementation details. In Object Oriented Programming, interfaces define abstract types that expose behavior, but contain no logic. Implementation is defined by the class or type that implements the interface.

@interface : (Annotation type)

Take the below example, which has a lot of comments:

public class Generation3List extends Generation2List {

   // Author: John Doe
   // Date: 3/17/2002
   // Current revision: 6
   // Last modified: 4/12/2004
   // By: Jane Doe
   // Reviewers: Alice, Bill, Cindy

   // class code goes here

}

Instead of this, you can declare an annotation type

 @interface ClassPreamble {
   String author();
   String date();
   int currentRevision() default 1;
   String lastModified() default "N/A";
   String lastModifiedBy() default "N/A";
   // Note use of array
   String[] reviewers();
}

which can then annotate a class as follows:

@ClassPreamble (
   author = "John Doe",
   date = "3/17/2002",
   currentRevision = 6,
   lastModified = "4/12/2004",
   lastModifiedBy = "Jane Doe",
   // Note array notation
   reviewers = {"Alice", "Bob", "Cindy"}
)
public class Generation3List extends Generation2List {

// class code goes here

}

PS: Many annotations replace comments in code.

Reference: http://docs.oracle.com/javase/tutorial/java/annotations/declaring.html

The VMware Authorization Service is not running

type Services at search, then start Services

enter image description here

then start all VM services

enter image description here

Pandas: Convert Timestamp to datetime.date

As of pandas 0.20.3, use .to_pydatetime() to convert any pandas.DateTimeIndex instances to Python datetime.datetime.

How can we stop a running java process through Windows cmd?

The answer which suggests something like taskkill /f /im java.exe will probably work, but if you want to kill only one java process instead of all, I can suggest doing it with the help of window titles. Expample:

Start

start "MyProgram" "C:/Program Files/Java/jre1.8.0_201/bin/java.exe" -jar MyProgram.jar

Stop

taskkill /F /FI "WINDOWTITLE eq MyProgram" /T

Call Stored Procedure within Create Trigger in SQL Server

finally...

set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON

GO
ALTER TRIGGER [dbo].[RA2Newsletter] 
   ON  [dbo].[Reiseagent] 
   AFTER INSERT
 AS
    declare
    @rAgent_Name nvarchar(50),
    @rAgent_Email nvarchar(50),
    @rAgent_IP nvarchar(50),
    @hotelID int,
    @retval int


BEGIN
    SET NOCOUNT ON;

    -- Insert statements for trigger here
    Select @rAgent_Name=rAgent_Name,@rAgent_Email=rAgent_Email,@rAgent_IP=rAgent_IP,@hotelID=hotelID  From Inserted
    EXEC insert2Newsletter '','',@rAgent_Name,@rAgent_Email,@rAgent_IP,@hotelID,'RA', @retval

END

Handling of non breaking space: <p>&nbsp;</p> vs. <p> </p>

How about a workaround? In my case I took the value of the textarea in a jQuery variable, and changed all "<p>&nbsp" to <p class="clear"> and clear class to have certain height and margin, as the following example:

jQuery

tinyMCE.triggerSave();
var val = $('textarea').val();
val = val.replace(/<p>&nbsp/g, '<p class="clear">');

the val is then saved to the database with the new val.

CSS

p.clear{height: 2px; margin-bottom: 3px;}

You can adjust the height & margin as you wish. And since 'p' is a display: block element. it should give you the expected output.

Hope that helps!

download and install visual studio 2008

https://www.microsoft.com/en-us/download/details.aspx?id=14258

which leads to:

Microsoft® Visual Studio Team System 2008 Database Edition GDR R2

Hope this is helpfull

Unable to access JSON property with "-" dash

In addition to this answer, note that in Node.js if you access JSON with the array syntax [] all nested JSON keys should follow that syntax

This is the wrong way

json.first.second.third['comment']

and will will give you the 'undefined' error.

This is the correct way

json['first']['second']['third']['comment'] 

Stacked Tabs in Bootstrap 3

You should not need to add this back in. This was removed purposefully. The documentation has changed somewhat and the CSS class that is necessary ("nav-stacked") is only mentioned under the pills component, but should work for tabs as well.

This tutorial shows how to use the Bootstrap 3 setup properly to do vertical tabs:
tutsme-webdesign.info/bootstrap-3-toggable-tabs-and-pills

How to prevent page from reloading after form submit - JQuery

The <button> element, when placed in a form, will submit the form automatically unless otherwise specified. You can use the following 2 strategies:

  1. Use <button type="button"> to override default submission behavior
  2. Use event.preventDefault() in the onSubmit event to prevent form submission

Solution 1:

  • Advantage: simple change to markup
  • Disadvantage: subverts default form behavior, especially when JS is disabled. What if the user wants to hit "enter" to submit?

Insert extra type attribute to your button markup:

<button id="button" type="button" value="send" class="btn btn-primary">Submit</button>

Solution 2:

  • Advantage: form will work even when JS is disabled, and respects standard form UI/UX such that at least one button is used for submission

Prevent default form submission when button is clicked. Note that this is not the ideal solution because you should be in fact listening to the submit event, not the button click event:

$(document).ready(function () {
  // Listen to click event on the submit button
  $('#button').click(function (e) {

    e.preventDefault();

    var name = $("#name").val();
    var email = $("#email").val();

    $.post("process.php", {
      name: name,
      email: email
    }).complete(function() {
        console.log("Success");
      });
  });
});

Better variant:

In this improvement, we listen to the submit event emitted from the <form> element:

$(document).ready(function () {
  // Listen to submit event on the <form> itself!
  $('#main').submit(function (e) {

    e.preventDefault();

    var name = $("#name").val();
    var email = $("#email").val();

    $.post("process.php", {
      name: name,
      email: email
    }).complete(function() {
        console.log("Success");
      });
  });
});

Even better variant: use .serialize() to serialize your form, but remember to add name attributes to your input:

The name attribute is required for .serialize() to work, as per jQuery's documentation:

For a form element's value to be included in the serialized string, the element must have a name attribute.

<input type="text" id="name" name="name" class="form-control mb-2 mr-sm-2 mb-sm-0" id="inlineFormInput" placeholder="Jane Doe">
<input type="text" id="email" name="email" class="form-control" id="inlineFormInputGroup" placeholder="[email protected]">

And then in your JS:

$(document).ready(function () {
  // Listen to submit event on the <form> itself!
  $('#main').submit(function (e) {

    // Prevent form submission which refreshes page
    e.preventDefault();

    // Serialize data
    var formData = $(this).serialize();

    // Make AJAX request
    $.post("process.php", formData).complete(function() {
      console.log("Success");
    });
  });
});

SQL Server Script to create a new user

CREATE LOGIN AdminLOGIN WITH PASSWORD = 'pass'
GO


Use MyDatabase;
GO

IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = N'AdminLOGIN')
BEGIN
    CREATE USER [AdminLOGIN] FOR LOGIN [AdminLOGIN]
    EXEC sp_addrolemember N'db_owner', N'AdminLOGIN'
    EXEC master..sp_addsrvrolemember @loginame = N'adminlogin', @rolename = N'sysadmin'
END;
GO

this full help you for network using:

1- Right-click on SQL Server instance at root of Object Explorer, click on Properties
Select Security from the left pane.

2- Select the SQL Server and Windows Authentication mode radio button, and click OK.

3- Right-click on the SQL Server instance, select Restart (alternatively, open up Services and restart the SQL Server service).

4- Close sql server application and reopen it

5- open 'SQL Server Configuration Manager' and tcp enabled for network

6-Double-click the TCP/IP protocol, go to the IP Addresses tab and scroll down to the IPAll section.

7-Specify the 1433 in the TCP Port field (or another port if 1433 is used by another MSSQL Server) and press the OK 

8-Open in Sql Server: Security And Login  And Right Click on Login Name And Select Peroperties And Select Server Roles And 
  Checked The Sysadmin And Bulkadmin then Ok.
9-firewall: Open cmd as administrator and type: 
      netsh firewall set portopening protocol = TCP port = 1433 name = SQLPort mode = ENABLE scope = SUBNET profile = CURRENT

c# open file with default application and parameters

I converted the VB code in the blog post linked by xsl to C# and modified it a bit:

public static bool TryGetRegisteredApplication(
                     string extension, out string registeredApp)
{
    string extensionId = GetClassesRootKeyDefaultValue(extension);
    if (extensionId == null)
    {
        registeredApp = null;
        return false;
    }

    string openCommand = GetClassesRootKeyDefaultValue(
            Path.Combine(new[] {extensionId, "shell", "open", "command"}));

    if (openCommand == null)
    {
        registeredApp = null;
        return false;
    }

    registeredApp = openCommand
                     .Replace("%1", string.Empty)
                     .Replace("\"", string.Empty)
                     .Trim();
    return true;
}

private static string GetClassesRootKeyDefaultValue(string keyPath)
{
    using (var key = Registry.ClassesRoot.OpenSubKey(keyPath))
    {
        if (key == null)
        {
            return null;
        }

        var defaultValue = key.GetValue(null);
        if (defaultValue == null)
        {
            return null;
        }

        return defaultValue.ToString();
    }
}

EDIT - this is unreliable. See Finding the default application for opening a particular file type on Windows.

Android Studio drawable folders

Actually you have selected Android from the tab change it to project.

Steps

enter image description here

Then you will found all folders.

enter image description here

Remove HTML Tags from an NSString on the iPhone

A quick and "dirty" (removes everything between < and >) solution, works with iOS >= 3.2:

-(NSString *) stringByStrippingHTML {
  NSRange r;
  NSString *s = [[self copy] autorelease];
  while ((r = [s rangeOfString:@"<[^>]+>" options:NSRegularExpressionSearch]).location != NSNotFound)
    s = [s stringByReplacingCharactersInRange:r withString:@""];
  return s;
}

I have this declared as a category os NSString.

Pandas get the most frequent values of a column

df['name'].value_counts()[:5].sort_values(ascending=False)

The value_counts will return a count object of pandas.core.series.Series and sort_values(ascending=False) will get you the highest values first.

Could not find folder 'tools' inside SDK

This can also happen due to the bad unzipping process of SDK.It Happend to me. Dont use inbuilt windows unzip process. use WINRAR software for unzipping sdk

Replace missing values with column mean

If DF is your data frame of numeric columns:

library(zoo)
na.aggregate(DF)

ADDED:

Using only the base of R define a function which does it for one column and then lapply to every column:

NA2mean <- function(x) replace(x, is.na(x), mean(x, na.rm = TRUE))
replace(DF, TRUE, lapply(DF, NA2mean))

The last line could be replaced with the following if it's OK to overwrite the input:

DF[] <- lapply(DF, NA2mean)

How to install all required PHP extensions for Laravel?

Laravel Server Requirements mention that BCMath, Ctype, JSON, Mbstring, OpenSSL, PDO, Tokenizer, and XML extensions are required. Most of the extensions are installed and enabled by default.

You can run the following command in Ubuntu to make sure the extensions are installed.

sudo apt install openssl php-common php-curl php-json php-mbstring php-mysql php-xml php-zip

PHP version specific installation (if PHP 7.4 installed)

sudo apt install php7.4-common php7.4-bcmath openssl php7.4-json php7.4-mbstring

You may need other PHP extensions for your composer packages. Find from links below.

PHP extensions for Ubuntu 20.04 LTS (Focal Fossa)

PHP extensions for Ubuntu 18.04 LTS (Bionic)

PHP extensions for Ubuntu 16.04 LTS (Xenial)

Passing an array by reference in C?

Arrays are effectively passed by reference by default. Actually the value of the pointer to the first element is passed. Therefore the function or method receiving this can modify the values in the array.

void SomeMethod(Coordinate Coordinates[]){Coordinates[0].x++;};
int main(){
  Coordinate tenCoordinates[10];
  tenCoordinates[0].x=0;
  SomeMethod(tenCoordinates[]);
  SomeMethod(&tenCoordinates[0]);
  if(0==tenCoordinates[0].x - 2;){
    exit(0);
  }
  exit(-1);
}

The two calls are equivalent, and the exit value should be 0;

How to get the file ID so I can perform a download of a file from Google Drive API on Android?

In my opinion the easiest and fastest way to get a Google Drive file ID is from Google Drive on the web. Right-click the file name and select Get shareable link. The last part of the link is the file ID. Then you can cancel the sharing.

Download Excel file via AJAX MVC

  $.ajax({
    global: false,
    url: SitePath + "/User/ExportTeamMembersInExcel",
    "data": { 'UserName': UserName, 'RoleId': RoleId, UserIds: AppraseeId },
    "type": "POST",
    "dataType": "JSON",
   "success": function (result) {
        debugger
        var bytes = new Uint8Array(result.FileContents);
        var blob = new Blob([bytes], { type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" });
        var link = document.createElement('a');
        link.href = window.URL.createObjectURL(blob);
        link.download = "myFileName.xlsx";
        link.click();
      },
    "error": function () {
        alert("error");
    }
})


[HttpPost]
    public JsonResult ExportTeamMembersInExcel(string UserName, long? RoleId, string[] UserIds)
    {
        MemoryStream stream = new MemoryStream();
        FileContentResult robj;
        DataTable data = objuserservice.ExportTeamToExcel(UserName, RoleId, UserIds);
        using (XLWorkbook wb = new XLWorkbook())
        {
            wb.Worksheets.Add(data, "TeamMembers");
            using (stream)
            {
                wb.SaveAs(stream);
            }
        }
        robj = File(stream.ToArray(), System.Net.Mime.MediaTypeNames.Application.Octet, "TeamMembers.xlsx");
        return Json(robj, JsonRequestBehavior.AllowGet);
    }

Java: Sending Multiple Parameters to Method

Suppose you have void method that prints many objects;

public static void print( Object... values){
   for(Object c : values){
      System.out.println(c);
   }
}

Above example I used vararge as an argument that accepts values from 0 to N.

From comments: What if 2 strings and 5 integers ??

Answer:

print("string1","string2",1,2,3,4,5);

How to upload, display and save images using node.js and express

First of all, you should make an HTML form containing a file input element. You also need to set the form's enctype attribute to multipart/form-data:

<form method="post" enctype="multipart/form-data" action="/upload">
    <input type="file" name="file">
    <input type="submit" value="Submit">
</form>

Assuming the form is defined in index.html stored in a directory named public relative to where your script is located, you can serve it this way:

const http = require("http");
const path = require("path");
const fs = require("fs");

const express = require("express");

const app = express();
const httpServer = http.createServer(app);

const PORT = process.env.PORT || 3000;

httpServer.listen(PORT, () => {
  console.log(`Server is listening on port ${PORT}`);
});

// put the HTML file containing your form in a directory named "public" (relative to where this script is located)
app.get("/", express.static(path.join(__dirname, "./public")));

Once that's done, users will be able to upload files to your server via that form. But to reassemble the uploaded file in your application, you'll need to parse the request body (as multipart form data).

In Express 3.x you could use express.bodyParser middleware to handle multipart forms but as of Express 4.x, there's no body parser bundled with the framework. Luckily, you can choose from one of the many available multipart/form-data parsers out there. Here, I'll be using multer:

You need to define a route to handle form posts:

const multer = require("multer");

const handleError = (err, res) => {
  res
    .status(500)
    .contentType("text/plain")
    .end("Oops! Something went wrong!");
};

const upload = multer({
  dest: "/path/to/temporary/directory/to/store/uploaded/files"
  // you might also want to set some limits: https://github.com/expressjs/multer#limits
});


app.post(
  "/upload",
  upload.single("file" /* name attribute of <file> element in your form */),
  (req, res) => {
    const tempPath = req.file.path;
    const targetPath = path.join(__dirname, "./uploads/image.png");

    if (path.extname(req.file.originalname).toLowerCase() === ".png") {
      fs.rename(tempPath, targetPath, err => {
        if (err) return handleError(err, res);

        res
          .status(200)
          .contentType("text/plain")
          .end("File uploaded!");
      });
    } else {
      fs.unlink(tempPath, err => {
        if (err) return handleError(err, res);

        res
          .status(403)
          .contentType("text/plain")
          .end("Only .png files are allowed!");
      });
    }
  }
);

In the example above, .png files posted to /upload will be saved to uploaded directory relative to where the script is located.

In order to show the uploaded image, assuming you already have an HTML page containing an img element:

<img src="/image.png" />

you can define another route in your express app and use res.sendFile to serve the stored image:

app.get("/image.png", (req, res) => {
  res.sendFile(path.join(__dirname, "./uploads/image.png"));
});

Is there a way to run Bash scripts on Windows?

You can always install Cygwin to run a Unix shell under Windows. I used Cygwin extensively with Window XP.

Xcode Objective-C | iOS: delay function / NSTimer help?

I would like to add a bit the answer by Avner Barr. When using int64, it appears that when we surpass the 1.0 value, the function seems to delay differently. So I think at this point, we should use NSTimeInterval.

So, the final code is:

NSTimeInterval delayInSeconds = 0.05;

dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){

//do your tasks here

});

Postgres manually alter sequence

The parentheses are misplaced:

SELECT setval('payments_id_seq', 21, true);  # next value will be 22

Otherwise you're calling setval with a single argument, while it requires two or three.

Open files always in a new tab

If you don't want to disable preview mode you can explicitly tell vscode to keep a specific tab open. As mentioned above a tab heading with italic text is in preview mode.

To get a tab out of preview mode you can either right click on the tab and choose keep open or use the shortcut cmd + k enter that is mapped to the command workbench.action.keepEditor.

Furthermore, double-clicking on a tab also gets it out of preview mode (verified in vscode 1.44.0).

Spring application context external properties?

<context:property-placeholder location="classpath*:spring/*.properties" />

If you place it somewhere in the classpath in a directory named spring (change names/dirs accordingly), you can access with above

<property name="locations" value ="config/springcontext.properties" />

this will be pointing to web-inf/classes/config/springcontext.properties

Error message 'Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.'

Another solution to know why exactly nothing works (from Microsoft connect):

  1. Add this code to the project:

    foreach (var asm in AppDomain.CurrentDomain.GetAssemblies())
    {
        asm.GetTypes();
    }
    
  2. Turn off generation serialization assemblies.

  3. Build and execute.

Browse and display files in a git repo without cloning

While you have to checkout a repository, you can skip checking out any files with --no-checkout and --depth 1:

$ time git clone --no-checkout --depth 1 https://github.com/torvalds/linux .
Cloning into '.'...
remote: Enumerating objects: 75646, done.
remote: Counting objects: 100% (75646/75646), done.
remote: Compressing objects: 100% (71197/71197), done.
remote: Total 75646 (delta 6176), reused 22237 (delta 3672), pack-reused 0
Receiving objects: 100% (75646/75646), 201.46 MiB | 7.27 MiB/s, done.
Resolving deltas: 100% (6176/6176), done.

real    0m46.117s
user    0m13.412s
sys     0m19.641s

And while there is only a .git directory:

$ ls -al
total 0
drwxr-xr-x   3 root  staff    96 Dec 26 23:57 .
drwxr-xr-x+ 71 root  staff  2272 Dec 27 00:03 ..
drwxr-xr-x  12 root  staff   384 Dec 26 23:58 .git

you can get a directory listing via:

$ git ls-tree --full-name --name-only -r HEAD | head
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Documentation/.gitignore
Documentation/ABI/README

or get the number of files via:

$ git ls-tree -r HEAD | wc -l
   71259

or get the total file size via:

$ git ls-tree -l -r HEAD | awk '/^[^-]/ {s+=$4} END {print s}'
1006679487

How do you create different variable names while in a loop?

Don't do this use a dictionary

import sys
this = sys.modules[__name__] # this is now your current namespace
for x in range(0,9):
    setattr(this, 'string%s' % x, 'Hello')

print string0
print string1
print string2
print string3
print string4
print string5
print string6
print string7
print string8

don't do this use a dict

globals() has risk as it gives you what the namespace is currently pointing to but this can change and so modifying the return from globals() is not a good idea

"unrecognized import path" with go get

The most common causes are:
1. An incorrectly configured GOROOT
OR
2. GOPATH is not set

How to downgrade Node version

For windows 10,

  • Uninstalling the node from the "Add or remove programs"
  • Installing the required version from https://nodejs.org/en/

worked for me.

Creating an abstract class in Objective-C

No, there is no way to create an abstract class in Objective-C.

You can mock an abstract class - by making the methods/ selectors call doesNotRecognizeSelector: and therefore raise an exception making the class unusable.

For example:

- (id)someMethod:(SomeObject*)blah
{
     [self doesNotRecognizeSelector:_cmd];
     return nil;
}

You can also do this for init.

Difference between Spring MVC and Struts MVC

If you wanna compare Spring MVC with struts consider below benefit of Spring MVC over Struts.

  1. Spring provides a very clean division between controllers, JavaBean models, and views.
  2. Spring's MVC is very flexible. Unlike Struts, which forces your Action and Form objects into concrete inheritance (thus taking away your single shot at concrete inheritance in Java), Spring MVC is entirely based on interfaces. Furthermore, just about every part of the Spring MVC framework is configurable via plugging in your own interface. Of course we also provide convenience classes as an implementation option.
  3. Spring, like WebWork, provides interceptors as well as controllers, making it easy to factor out behavior common to the handling of many requests.
  4. Spring MVC is truly view-agnostic. You don't get pushed to use JSP if you don't want to; you can use Velocity, XLST or other view technologies. If you want to use a custom view mechanism - for example, your own templating language - you can easily implement the Spring View interface to integrate it.
  5. Spring Controllers are configured via IoC like any other objects. This makes them easy to test, and beautifully integrated with other objects managed by Spring.
  6. Spring MVC web tiers are typically easier to test than Struts web tiers, due to the avoidance of forced concrete inheritance and explicit dependence of controllers on the dispatcher servlet.
  7. The web tier becomes a thin layer on top of a business object layer. This encourages good practice. Struts and other dedicated web frameworks leave you on your own in implementing your business objects; Spring provides an integrated framework for all tiers of your application

How do I revert back to an OpenWrt router configuration?

Those who are facing this problem: Don't panic.

Short answer:

Restart your router, and this problem will be fixed. (But if your restart button is not working, you need to do a nine-step process to do the restart. Hitting the restart button is just one of them.)

Long answer: Let's learn how to restart the router.

  1. Set your PC's IP address: 192.168.1.2 and subnetmask 255.255.255.0 and gateway 192.168.1.1
  2. Power off the router
  3. Disconnect the WAN cable
  4. Only connect your PC Ethernet cable to ETH0
  5. Power on the router
  6. Wait for the router to start the boot sequence (SYS LED starts blinking)
  7. When the SYS LED is blinking, hit the restart button (the SYS LED will be blinking at a faster rate means your router is in failsafe mode). (You have to hit the button before the router boots.)
  8. telnet 192.168.1.1
  9. Run these commands:

    mount_root ## this remounts your partitions from read-only to read/write mode
    
    firstboot  ## This will reset your router after reboot
    
    reboot -f ## And force reboot
    
  10. Log in the web interface using web browser.

link to see the official failsafe mode.

Detecting when a div's height changes using jQuery

There is a jQuery plugin that can deal with this very well

http://www.jqui.net/jquery-projects/jquery-mutate-official/

here is a demo of it with different scenarios as to when the height change, if you resize the red bordered div.

http://www.jqui.net/demo/mutate/

Using ng-click vs bind within link function of Angular Directive

I think it is fine because I've seen many people doing this way.

If you are just defining the event handler within the directive, you do not have to define it on the scope, though. Following would be fine.

myApp.directive('clickme', function() {
  return function(scope, element, attrs) {
    var clickingCallback = function() {
      alert('clicked!')
    };
    element.bind('click', clickingCallback);
  }
});

How to disable mouse scroll wheel scaling with Google Maps API

I created a more developed jQuery plugin that allows you to lock or unlock the map with a nice button.

This plugin disables the Google Maps iframe with a transparent overlay div and adds a button for unlockit. You must press for 650 milliseconds to unlock it.

You can change all the options for your convenience. Check it at https://github.com/diazemiliano/googlemaps-scrollprevent

Here's some example.

_x000D_
_x000D_
(function() {_x000D_
  $(function() {_x000D_
    $("#btn-start").click(function() {_x000D_
      $("iframe[src*='google.com/maps']").scrollprevent({_x000D_
        printLog: true_x000D_
      }).start();_x000D_
      return $("#btn-stop").click(function() {_x000D_
        return $("iframe[src*='google.com/maps']").scrollprevent().stop();_x000D_
      });_x000D_
    });_x000D_
    return $("#btn-start").trigger("click");_x000D_
  });_x000D_
}).call(this);
_x000D_
.embed-container {_x000D_
  position: relative !important;_x000D_
  padding-bottom: 56.25% !important;_x000D_
  height: 0 !important;_x000D_
  overflow: hidden !important;_x000D_
  max-width: 100% !important;_x000D_
}_x000D_
.embed-container iframe {_x000D_
  position: absolute !important;_x000D_
  top: 0 !important;_x000D_
  left: 0 !important;_x000D_
  width: 100% !important;_x000D_
  height: 100% !important;_x000D_
}_x000D_
.mapscroll-wrap {_x000D_
  position: static !important;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>_x000D_
<script src="https://cdn.rawgit.com/diazemiliano/googlemaps-scrollprevent/v.0.6.5/dist/googlemaps-scrollprevent.min.js"></script>_x000D_
<div class="embed-container">_x000D_
  <iframe src="https://www.google.com/maps/embed?pb=!1m18!1m12!1m3!1d12087.746318586604!2d-71.64614110000001!3d-40.76341959999999!2m3!1f0!2f0!3f0!3m2!1i1024!2i768!4f13.1!3m3!1m2!1s0x9610bf42e48faa93%3A0x205ebc786470b636!2sVilla+la+Angostura%2C+Neuqu%C3%A9n!5e0!3m2!1ses-419!2sar!4v1425058155802"_x000D_
  width="400" height="300" frameborder="0" style="border:0"></iframe>_x000D_
</div>_x000D_
<p><a id="btn-start" href="#">"Start Scroll Prevent"</a>  <a id="btn-stop" href="#">"Stop Scroll Prevent"</a>_x000D_
</p>
_x000D_
_x000D_
_x000D_

Connect with SSH through a proxy

In my case since I had a jump host or Bastion host on the way, and because the signatures on these bastion nodes had changed since they were imported into known_hosts file, I just needed to delete those entries/lines from the following file:

/Users/a.abdi-kelishami/.ssh/known_hosts

From above file, delete those lines referring to the bastion hosts.

Compare every item to every other item in ArrayList

for (int i = 0; i < list.size(); i++) {
  for (int j = i+1; j < list.size(); j++) {
    // compare list.get(i) and list.get(j)
  }
}

ASP.NET MVC Return Json Result?

It should be :

public async Task<ActionResult> GetSomeJsonData()
{
    var model = // ... get data or build model etc.

    return Json(new { Data = model }, JsonRequestBehavior.AllowGet); 
}

or more simply:

return Json(model, JsonRequestBehavior.AllowGet); 

I did notice that you are calling GetResources() from another ActionResult which wont work. If you are looking to get JSON back, you should be calling GetResources() from ajax directly...

How to convert OutputStream to InputStream?

I encountered the same problem with converting a ByteArrayOutputStream to a ByteArrayInputStream and solved it by using a derived class from ByteArrayOutputStream which is able to return a ByteArrayInputStream that is initialized with the internal buffer of the ByteArrayOutputStream. This way no additional memory is used and the 'conversion' is very fast:

package info.whitebyte.utils;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;

/**
 * This class extends the ByteArrayOutputStream by 
 * providing a method that returns a new ByteArrayInputStream
 * which uses the internal byte array buffer. This buffer
 * is not copied, so no additional memory is used. After
 * creating the ByteArrayInputStream the instance of the
 * ByteArrayInOutStream can not be used anymore.
 * <p>
 * The ByteArrayInputStream can be retrieved using <code>getInputStream()</code>.
 * @author Nick Russler
 */
public class ByteArrayInOutStream extends ByteArrayOutputStream {
    /**
     * Creates a new ByteArrayInOutStream. The buffer capacity is
     * initially 32 bytes, though its size increases if necessary.
     */
    public ByteArrayInOutStream() {
        super();
    }

    /**
     * Creates a new ByteArrayInOutStream, with a buffer capacity of
     * the specified size, in bytes.
     *
     * @param   size   the initial size.
     * @exception  IllegalArgumentException if size is negative.
     */
    public ByteArrayInOutStream(int size) {
        super(size);
    }

    /**
     * Creates a new ByteArrayInputStream that uses the internal byte array buffer 
     * of this ByteArrayInOutStream instance as its buffer array. The initial value 
     * of pos is set to zero and the initial value of count is the number of bytes 
     * that can be read from the byte array. The buffer array is not copied. This 
     * instance of ByteArrayInOutStream can not be used anymore after calling this
     * method.
     * @return the ByteArrayInputStream instance
     */
    public ByteArrayInputStream getInputStream() {
        // create new ByteArrayInputStream that respects the current count
        ByteArrayInputStream in = new ByteArrayInputStream(this.buf, 0, this.count);

        // set the buffer of the ByteArrayOutputStream 
        // to null so it can't be altered anymore
        this.buf = null;

        return in;
    }
}

I put the stuff on github: https://github.com/nickrussler/ByteArrayInOutStream

How can I get form data with JavaScript/jQuery?

Here's a really simple and short soluton that even doesn't require Jquery.

var formElements=document.getElementById("myForm").elements;    
var postData={};
for (var i=0; i<formElements.length; i++)
    if (formElements[i].type!="submit")//we dont want to include the submit-buttom
        postData[formElements[i].name]=formElements[i].value;

PHP Warning: POST Content-Length of 8978294 bytes exceeds the limit of 8388608 bytes in Unknown on line 0

Go to C:\xamppp\php. Set these values in php.ini:

upload_max_filesize = 1000M
post_max_size = 0M

Maven- No plugin found for prefix 'spring-boot' in the current project and in the plugin groups

If you don't want to use

<parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>(...)</version>
</parent>

as a parent POM, you may use the

mvn org.springframework.boot:spring-boot-maven-plugin:run

command instead.

Razor HtmlHelper Extensions (or other namespaces for views) Not Found

Since the Beta, Razor uses a different config section for globally defining namespace imports. In your Views\Web.config file you should add the following:

<configSections>
  <sectionGroup name="system.web.webPages.razor" type="System.Web.WebPages.Razor.Configuration.RazorWebSectionGroup, System.Web.WebPages.Razor, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
    <section name="host" type="System.Web.WebPages.Razor.Configuration.HostSection, System.Web.WebPages.Razor, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
    <section name="pages" type="System.Web.WebPages.Razor.Configuration.RazorPagesSection, System.Web.WebPages.Razor, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
  </sectionGroup>
</configSections>

<system.web.webPages.razor>
  <host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
  <pages pageBaseType="System.Web.Mvc.WebViewPage">
    <namespaces>
      <add namespace="System.Web.Mvc" />
      <add namespace="System.Web.Mvc.Ajax" />
      <add namespace="System.Web.Mvc.Html" />
      <add namespace="System.Web.Routing" />
      <!-- Your namespace here -->
    </namespaces>
  </pages>
</system.web.webPages.razor>

Use the MVC 3 upgrade tool to automatically ensure you have the right config values.

Note that you might need to close and reopen the file for the changes to be picked up by the editor.

how can I Update top 100 records in sql server

update tb set  f1=1 where id in (select top 100 id from tb where f1=0)

How do I import modules or install extensions in PostgreSQL 9.1+?

In addition to the extensions which are maintained and provided by the core PostgreSQL development team, there are extensions available from third parties. Notably, there is a site dedicated to that purpose: http://www.pgxn.org/

How do you dynamically allocate a matrix?

arr = new int[cols*rows];

If you either don't mind syntax

arr[row * cols + col] = Aij;

or use operator[] overaloading somewhere. This may be more cache-friendly than array of arrays, or may be not, more probably you shouldn't care about it. I just want to point out that a) array of arrays is not only solution, b) some operations are more easier to implement if matrix located in one block of memory. E.g.

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

one line shorter than

for(int r=0;i < rows;++r)
  for(int c=0;i < cols;++s)
     matrix[r][c]=someOtherMatrix[r][c];

though adding rows to such matrix is more painful

What is the difference between bindParam and bindValue?

For the most common purpose, you should use bindValue.

bindParam has two tricky or unexpected behaviors:

  • bindParam(':foo', 4, PDO::PARAM_INT) does not work, as it requires passing a variable (as reference).
  • bindParam(':foo', $value, PDO::PARAM_INT) will change $value to string after running execute(). This, of course, can lead to subtle bugs that might be difficult to catch.

Source: http://php.net/manual/en/pdostatement.bindparam.php#94711

Push an associative item into an array in JavaScript

To make something like associative array in JavaScript you have to use objects. ?

_x000D_
_x000D_
var obj = {}; // {} will create an object
var name = "name";
var val = 2;
obj[name] = val;
console.log(obj);
_x000D_
_x000D_
_x000D_

DEMO: http://jsfiddle.net/bz8pK/1/

How do I programmatically force an onchange event on an input?

if you're using jQuery you would have:

$('#elementId').change(function() { alert('Do Stuff'); });

or MS AJAX:

$addHandler($get('elementId'), 'change', function(){ alert('Do Stuff'); });

Or in the raw HTML of the element:

<input type="text" onchange="alert('Do Stuff');" id="myElement" />

After re-reading the question I think I miss-read what was to be done. I've never found a way to update a DOM element in a manner which will force a change event, what you're best doing is having a separate event handler method, like this:

$addHandler($get('elementId'), 'change', elementChanged);
function elementChanged(){
  alert('Do Stuff!');
}
function editElement(){
  var el = $get('elementId');
  el.value = 'something new';
  elementChanged();
}

Since you're already writing a JavaScript method which will do the changing it's only 1 additional line to call.

Or, if you are using the Microsoft AJAX framework you can access all the event handlers via:

$get('elementId')._events

It'd allow you to do some reflection-style workings to find the right event handler(s) to fire.

Keyboard shortcut for Jump to Previous View Location (Navigate back/forward) in IntelliJ IDEA

Depends on the Keymap selected.

Keymap: Mac OS X ? + Left Right Arrow Keys
Keymap: Mac OS X 10.5+ ? + [ / ]

I was facing similar problems in Pycharm. To resolve change your Keymap in Preferences.

What's the "average" requests per second for a production web application?

You can search "slashdot effect analysis" for graphs of what you would see if some aspect of the site suddenly became popular in the news, e.g. this graph on wiki.

Web-applications that survive tend to be the ones which can generate static pages instead of putting every request through a processing language.

There was an excellent video (I think it might have been on ted.com? I think it might have been by flickr web team? Does someone know the link?) with ideas on how to scale websites beyond the single server, e.g. how to allocate connections amongst the mix of read-only and read-write servers to get best effect for various types of users.

Hide/encrypt password in bash file to stop accidentally seeing it

OpenSSL provides a passwd command that can encrypt but doesn't decrypt as it only does hashes. You could also download something like aesutil so you can use a capable and well-known symmetric encryption routine.

For example:

#!/bin/sh    
# using aesutil
SALT=$(mkrand 15) # mkrand generates a 15-character random passwd
MYENCPASS="i/b9pkcpQAPy7BzH2JlqHVoJc2mNTBM=" # echo "passwd" | aes -e -b -B -p $SALT 
MYPASS=$(echo "$MYENCPASS" | aes -d -b -p $SALT)

# and usage
serverControl.sh -u admin -p $MYPASS -c shutdown

Cannot connect to MySQL Workbench on mac. Can't connect to MySQL server on '127.0.0.1' (61) Mac Macintosh

I am using those commands on MacOs after getting the same error

sudo /usr/local/mysql/support-files/mysql.server start

sudo /usr/local/mysql/support-files/mysql.server stop

sudo /usr/local/mysql/support-files/mysql.server restart

Download a div in a HTML page as pdf using javascript

Yes, it's possible to To capture div as PDFs in JS. You can can check the solution provided by https://grabz.it. They have nice and clean JavaScript API which will allow you to capture the content of a single HTML element such as a div or a span.

So, yo use it you will need and app+key and the free SDK. The usage of it is as following:

Let's say you have a HTML:

<div id="features">
    <h4>Acme Camera</h4>
    <label>Price</label>$399<br />
    <label>Rating</label>4.5 out of 5
</div>
<p>Cras ut velit sed purus porttitor aliquam. Nulla tristique magna ac libero tempor, ac vestibulum felisvulput ate. Nam ut velit eget
risus porttitor tristique at ac diam. Sed nisi risus, rutrum a metus suscipit, euismod tristique nulla. Etiam venenatis rutrum risus at
blandit. In hac habitasse platea dictumst. Suspendisse potenti. Phasellus eget vehicula felis.</p>

To capture what is under the features id you will need to:

//add the sdk
<script type="text/javascript" src="grabzit.min.js"></script>
<script type="text/javascript">
//login with your key and secret. 
GrabzIt("KEY", "SECRET").ConvertURL("http://www.example.com/my-page.html",
{"target": "#features", "format": "pdf"}).Create();
</script>

You need to replace the http://www.example.com/my-page.html with your target url and #feature per your CSS selector.

That's all. Now, when the page is loaded an image screenshot will now be created in the same location as the script tag, which will contain all of the contents of the features div and nothing else.

The are other configuration and customization you can do to the div-screenshot mechanism, please check them out here

docker build with --build-arg with multiple arguments

Use --build-arg with each argument.

If you are passing two argument then add --build-arg with each argument like:

docker build \
-t essearch/ess-elasticsearch:1.7.6 \
--build-arg number_of_shards=5 \
--build-arg number_of_replicas=2 \
--no-cache .

Get the last three chars from any string - Java

Here's some terse code that does the job using regex:

String last3 = str.replaceAll(".*?(.?.?.?)?$", "$1");

This code returns up to 3; if there are less than 3 it just returns the string.

This is how to do it safely without regex in one line:

String last3 = str == null || str.length() < 3 ? 
    str : str.substring(str.length() - 3);

By "safely", I mean without throwing an exception if the string is nulls or shorter than 3 characters (all the other answers are not "safe").


The above code is identical in effect to this code, if you prefer a more verbose, but potentially easier-to-read form:

String last3;
if (str == null || str.length() < 3) {
    last3 = str;
} else {
    last3 = str.substring(str.length() - 3);
}

dplyr change many data types

You can use the standard evaluation version of mutate_each (which is mutate_each_) to change the column classes:

dat %>% mutate_each_(funs(factor), l1) %>% mutate_each_(funs(as.numeric), l2)

How do I run a Java program from the command line on Windows?

As of Java 9, the JDK includes jshell, a Java REPL.

Assuming the JDK 9+ bin directory is correctly added to your path, you will be able to simply:

  1. Run jshell File.javaFile.java being your file of course.
  2. A prompt will open, allowing you to call the main method: jshell> File.main(null).
  3. To close the prompt and end the JVM session, use /exit

Full documentation for JShell can be found here.

insert password into database in md5 format?

if you want to use md5 encryptioon you can do it in your php script

$pass = $_GET['pass'];

$newPass = md5($pass)

and then insert it into the database that way, however MD5 is a one way encryption method and is near on impossible to decrypt without difficulty

PHPExcel - set cell type before writing a value in it

Followed Mark's advise and did this to set the default number formatting to text in the whole workbook:

$objPHPExcel = new PHPExcel(); 
$objPHPExcel->getDefaultStyle()
    ->getNumberFormat()
    ->setFormatCode(
        PHPExcel_Style_NumberFormat::FORMAT_TEXT
    );

And it works flawlessly. Thank you, Mark Baker.

performSelector may cause a leak because its selector is unknown

To ignore the error only in the file with the perform selector, add a #pragma as follows:

#pragma clang diagnostic ignored "-Warc-performSelector-leaks"

This would ignore the warning on this line, but still allow it throughout the rest of your project.

CMake is not able to find BOOST libraries

I had the same issue inside an alpine docker container, my solution was to add the boost-dev apk library because libboost-dev was not available.

How to use z-index in svg elements?

The clean, fast, and easy solutions posted as of the date of this answer are unsatisfactory. They are constructed over the flawed statement that SVG documents lack z order. Libraries are not necessary either. One line of code can perform most operations to manipulate the z order of objects or groups of objects that might be required in the development of an app that moves 2D objects around in an x-y-z space.

Z Order Definitely Exists in SVG Document Fragments

What is called an SVG document fragment is a tree of elements derived from the base node type SVGElement. The root node of an SVG document fragment is an SVGSVGElement, which corresponds to an HTML5 <svg> tag. The SVGGElement corresponds to the <g> tag and permits aggregating children.

Having a z-index attribute on the SVGElement as in CSS would defeat the SVG rendering model. Sections 3.3 and 3.4 of W3C SVG Recommendation v1.1 2nd Edition state that SVG document fragments (trees of offspring from an SVGSVGElement) are rendered using what is called a depth first search of the tree. That scheme is a z order in every sense of the term.

Z order is actually a computer vision shortcut to avoid the need for true 3D rendering with the complexities and computing demands of ray tracing. The linear equation for the implicit z-index of elements in an SVG document fragment.

z-index = z-index_of_svg_tag + depth_first_tree_index / tree_node_qty

This is important because if you want to move a circle that was below a square to above it, you simply insert the square before the circle. This can be done easily in JavaScript.

Supporting Methods

SVGElement instances have two methods that support simple and easy z order manipulation.

  • parent.removeChild(child)
  • parent.insertBefore(child, childRef)

The Correct Answer That Doesn't Create a Mess

Because the SVGGElement (<g> tag) can be removed and inserted just as easily as a SVGCircleElement or any other shape, image layers typical of Adobe products and other graphics tools can be implemented with ease using the SVGGElement. This JavaScript is essentially a Move Below command.

parent.insertBefore(parent.removeChild(gRobot), gDoorway)

If the layer of a robot drawn as children of SVGGElement gRobot was before the doorway drawn as children of SVGGElement gDoorway, the robot is now behind the doorway because the z order of the doorway is now one plus the z order of the robot.

A Move Above command is almost as easy.

parent.insertBefore(parent.removeChild(gRobot), gDoorway.nextSibling())

Just think a=a and b=b to remember this.

insert after = move above
insert before = move below

Leaving the DOM in a State Consistent With the View

The reason this answer is correct is because it is minimal and complete and, like the internals of Adobe products or other well designed graphics editors, leaves the internal representation in a state that is consistent with the view created by rendering.

Alternative But Limited Approach

Another approach commonly used is to use CSS z-index in conjunction with multiple SVG document fragments (SVG tags) with mostly transparent backgrounds in all but the bottom one. Again, this defeats the elegance of the SVG rendering model, making it difficult to move objects up or down in the z order.


NOTES:

  1. (https://www.w3.org/TR/SVG/render.html v 1.1, 2nd Edition, 16 August 2011)

    3.3 Rendering Order Elements in an SVG document fragment have an implicit drawing order, with the first elements in the SVG document fragment getting "painted" first. Subsequent elements are painted on top of previously painted elements.

    3.4 How groups are rendered Grouping elements such as the ‘g’ element (see container elements) have the effect of producing a temporary separate canvas initialized to transparent black onto which child elements are painted. Upon the completion of the group, any filter effects specified for the group are applied to create a modified temporary canvas. The modified temporary canvas is composited into the background, taking into account any group-level masking and opacity settings on the group.

How to select distinct rows in a datatable and store into an array

string[] TobeDistinct = {"Name","City","State"};
DataTable dtDistinct = GetDistinctRecords(DTwithDuplicate, TobeDistinct);

//Following function will return Distinct records for Name, City and State column.
public static DataTable GetDistinctRecords(DataTable dt, string[] Columns)
{
    DataTable dtUniqRecords = new DataTable();
    dtUniqRecords = dt.DefaultView.ToTable(true, Columns);
    return dtUniqRecords;
}

Java Pass Method as Parameter

Use the java.lang.reflect.Method object and call invoke

Object not found! The requested URL was not found on this server. localhost

Simply my project wasn't in htdocs thats why it was showing me an this error make sure you put your project in HTdocs not in directory inside it

Select and trigger click event of a radio button in jquery

You are triggering the event before the event is even bound.

Just move the triggering of the event to after attaching the event.

$(document).ready(function() {
  $("#checkbox_div input:radio").click(function() {

    alert("clicked");

   });

  $("input:radio:first").prop("checked", true).trigger("click");

});

Check Fiddle

How do you express binary literals in Python?

I am pretty sure this is one of the things due to change in Python 3.0 with perhaps bin() to go with hex() and oct().

EDIT: lbrandy's answer is correct in all cases.

Count number of records returned by group by

I was trying to achieve the same without subquery and was able to get the required result as below

SELECT DISTINCT COUNT(*) OVER () AS TotalRecords
FROM temptable
GROUP BY column_1, column_2, column_3, column_4

Reflection - get attribute name and value on property

I wrote this into a dynamic method since I use lots of attributes throughout my application. Method:

public static dynamic GetAttribute(Type objectType, string propertyName, Type attrType)
    {
        //get the property
        var property = objectType.GetProperty(propertyName);

        //check for object relation
        return property.GetCustomAttributes().FirstOrDefault(x => x.GetType() == attrType);
    }

Usage:

var objectRelAttr = GetAttribute(typeof(Person), "Country", typeof(ObjectRelationAttribute));

var displayNameAttr = GetAttribute(typeof(Product), "Category", typeof(DisplayNameAttribute));

Hope this helps anyone

How to convert byte array to string

Assuming that you are using UTF-8 encoding:

string convert = "This is the string to be converted";

// From string to byte array
byte[] buffer = System.Text.Encoding.UTF8.GetBytes(convert);

// From byte array to string
string s = System.Text.Encoding.UTF8.GetString(buffer, 0, buffer.Length);

How to select the rows with maximum values in each group with dplyr?

df %>% group_by(A,B) %>% slice(which.max(value))

How can I use inverse or negative wildcards when pattern matching in a unix/linux shell?

Not in bash (that I know of), but:

cp `ls | grep -v Music` /target_directory

I know this is not exactly what you were looking for, but it will solve your example.

Getting unix timestamp from Date()

In java 8, it's convenient to use the new date lib and getEpochSecond method to get the timestamp (it's in second)

Instant.now().getEpochSecond();

Fastest way to check if a file exist using standard C++/C++11/C?

inline bool exist(const std::string& name)
{
    ifstream file(name);
    if(!file)            // If the file was not found, then file is 0, i.e. !file=1 or true.
        return false;    // The file was not found.
    else                 // If the file was found, then file is non-0.
        return true;     // The file was found.
}

Return True, False and None in Python

It's impossible to say without seeing your actual code. Likely the reason is a code path through your function that doesn't execute a return statement. When the code goes down that path, the function ends with no value returned, and so returns None.

Updated: It sounds like your code looks like this:

def b(self, p, data): 
    current = p 
    if current.data == data: 
        return True 
    elif current.data == 1:
        return False 
    else: 
        self.b(current.next, data)

That else clause is your None path. You need to return the value that the recursive call returns:

    else:
        return self.b(current.next, data)

BTW: using recursion for iterative programs like this is not a good idea in Python. Use iteration instead. Also, you have no clear termination condition.

/usr/lib/x86_64-linux-gnu/libstdc++.so.6: version CXXABI_1.3.8' not found

I've got correct solution here.

The best way to correctly install gcc-4.9 and set it as your default gcc version use:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-4.9 g++-4.9
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.9 60 --slave /usr/bin/g++ g++ /usr/bin/g++-4.9

The --slave, with g++, will cause g++ to be switched along with gcc, to the same version. But, at this point gcc-4.9 will be your only version configured in update-alternatives, so add 4.8 to update-alternatives, so there actually is an alternative, by using:

sudo apt-get install gcc-4.8 g++-4.8
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 60 --slave /usr/bin/g++ g++ /usr/bin/g++-4.8

Then you can check which one that is set, and change back and forth using:

sudo update-alternatives --config gcc

NOTE: You could skip installing the PPA Repository and just use /usr/bin/gcc-4.9-base but I prefer using the fresh updated toolchains.

How to change workspace and build record Root Directory on Jenkins?

You can also edit the config.xml file in your JENKINS_HOME directory. Use c32hedge's response as a reference and set the workspace location to whatever you want between the tags

Regex to match alphanumeric and spaces

I got it:

string clean = Regex.Replace(q, @"[^a-zA-Z0-9\s]", string.Empty);

Didn't know you could put \s in the brackets

How can I get input radio elements to horizontally align?

Here is updated Fiddle

Simply remove </br> between input radio's

<div class="clearBoth"></div>
<input type="radio" name="editList" value="always">Always
<input type="radio" name="editList" value="never">Never
<input type="radio" name="editList" value="costChange">Cost Change
<div class="clearBoth"></div>

How do I view an older version of an SVN file?

It is also interesting to compare the file of the current working revision with the same file of another revision.

You can do as follows:

$ svn diff -r34 file

How to set caret(cursor) position in contenteditable element (div)?

In most browsers, you need the Range and Selection objects. You specify each of the selection boundaries as a node and an offset within that node. For example, to set the caret to the fifth character of the second line of text, you'd do the following:

_x000D_
_x000D_
function setCaret() {
    var el = document.getElementById("editable")
    var range = document.createRange()
    var sel = window.getSelection()
    
    range.setStart(el.childNodes[2], 5)
    range.collapse(true)
    
    sel.removeAllRanges()
    sel.addRange(range)
}
_x000D_
<div id="editable" contenteditable="true">
  text text text<br>text text text<br>text text text<br>
</div>

<button id="button" onclick="setCaret()">focus</button>
_x000D_
_x000D_
_x000D_

IE < 9 works completely differently. If you need to support these browsers, you'll need different code.

jsFiddle example: http://jsfiddle.net/timdown/vXnCM/

Python function pointer

Why not store the function itself? myvar = mypackage.mymodule.myfunction is much cleaner.

How to capture no file for fs.readFileSync()?

Try using Async instead to avoid blocking the only thread you have with NodeJS. Check this example:

const util = require('util');
const fs = require('fs');
const path = require('path');
const readFileAsync = util.promisify(fs.readFile);

const readContentFile = async (filePath) => {
  // Eureka, you are using good code practices here!
  const content = await readFileAsync(path.join(__dirname, filePath), {
    encoding: 'utf8'
  })
  return content;
}

Later can use this async function with try/catch from any other function:

const anyOtherFun = async () => {
  try {
    const fileContent = await readContentFile('my-file.txt');
  } catch (err) {
    // Here you get the error when the file was not found,
    // but you also get any other error
  }
}

Happy Coding!

How to open a specific port such as 9090 in Google Compute Engine

You'll need to add a firewall rule to open inbound access to tcp:9090 to your instances. If you have more than the two instances, and you only want to open 9090 to those two, you'll want to make sure that there is a tag that those two instances share. You can add or update tags via the console or the command-line; I'd recommend using the GUI for that if needed because it handles the read-modify-write cycle with setinstancetags.

If you want to open port 9090 to all instances, you can create a firewall rule like:

gcutil addfirewall allow-9090 --allowed=tcp:9090

which will apply to all of your instances.

If you only want to open port 9090 to the two instances that are serving your application, make sure that they have a tag like my-app, and then add a firewall like so:

gcutil addfirewall my-app-9090 --allowed=tcp:9090 --target_tags=my-app

You can read more about creating and managing firewalls in GCE here.

Set padding for UITextField with UITextBorderStyleNone

Swift 3 Solution

class CustomTextField: UITextField {

 override func textRect(forBounds bounds: CGRect) -> CGRect {
  return CGRect(x: bounds.origin.x + 10, y: bounds.origin.y + 8, width: bounds.size.width - 20, height: bounds.size.height - 16)
 }

 override func editingRect(forBounds bounds: CGRect) -> CGRect {
  return self.textRect(forBounds: bounds)
 }
}

Adding a column to an existing table in a Rails migration

To add a column I just had to follow these steps :

  1. rails generate migration add_fieldname_to_tablename fieldname:string

    Alternative

    rails generate migration addFieldnameToTablename

    Once the migration is generated, then edit the migration and define all the attributes you want that column added to have.

    Note: Table names in Rails are always plural (to match DB conventions). Example using one of the steps mentioned previously-

    rails generate migration addEmailToUsers

  2. rake db:migrate

Or

  1. You can change the schema in from db/schema.rb, Add the columns you want in the SQL query.
  2. Run this command: rake db:schema:load

    Warning/Note

    Bear in mind that, running rake db:schema:load automatically wipes all data in your tables.

Finding what branch a Git commit came from

Aside from searching through all of the tree until you find a matching hash, no.

How can I use NSError in my iPhone App?

Well it's a little bit out of question scope but in case you don't have an option for NSError you can always display the Low level error:

 NSLog(@"Error = %@ ",[NSString stringWithUTF8String:strerror(errno)]);

Is there a Sleep/Pause/Wait function in JavaScript?

You can't (and shouldn't) block processing with a sleep function. However, you can use setTimeout to kick off a function after a delay:

setTimeout(function(){alert("hi")}, 1000);

Depending on your needs, setInterval might be useful, too.

Iterating through a List Object in JSP

 <c:forEach items="${sessionScope.empL}" var="emp">
            <tr>
                <td>Employee ID: <c:out value="${emp.eid}"/></td>
                <td>Employee Pass: <c:out value="${emp.ename}"/></td>  
            </tr>
        </c:forEach>

VB.NET - If string contains "value1" or "value2"

In addition to the answers already given it will be quicker if you use OrElse instead of Or because the second test is short circuited. This is especially true if you know that one string is more likely than the other in which case place this first:

If strMyString.Contains("Most Likely To Find") OrElse strMyString.Contains("Less Likely to Find") Then
    'Code
End if

Call a method of a controller from another controller using 'scope' in AngularJS

Here is good Demo in Fiddle how to use shared service in directive and other controllers through $scope.$on

HTML

<div ng-controller="ControllerZero">
    <input ng-model="message" >
    <button ng-click="handleClick(message);">BROADCAST</button>
</div>

<div ng-controller="ControllerOne">
    <input ng-model="message" >
</div>

<div ng-controller="ControllerTwo">
    <input ng-model="message" >
</div>

<my-component ng-model="message"></my-component>

JS

var myModule = angular.module('myModule', []);

myModule.factory('mySharedService', function($rootScope) {
    var sharedService = {};

    sharedService.message = '';

    sharedService.prepForBroadcast = function(msg) {
        this.message = msg;
        this.broadcastItem();
    };

    sharedService.broadcastItem = function() {
        $rootScope.$broadcast('handleBroadcast');
    };

    return sharedService;
});

By the same way we can use shared service in directive. We can implement controller section into directive and use $scope.$on

myModule.directive('myComponent', function(mySharedService) {
    return {
        restrict: 'E',
        controller: function($scope, $attrs, mySharedService) {
            $scope.$on('handleBroadcast', function() {
                $scope.message = 'Directive: ' + mySharedService.message;
            });
        },
        replace: true,
        template: '<input>'
    };
});

And here three our controllers where ControllerZero used as trigger to invoke prepForBroadcast

function ControllerZero($scope, sharedService) {
    $scope.handleClick = function(msg) {
        sharedService.prepForBroadcast(msg);
    };

    $scope.$on('handleBroadcast', function() {
        $scope.message = sharedService.message;
    });
}

function ControllerOne($scope, sharedService) {
    $scope.$on('handleBroadcast', function() {
        $scope.message = 'ONE: ' + sharedService.message;
    });
}

function ControllerTwo($scope, sharedService) {
    $scope.$on('handleBroadcast', function() {
        $scope.message = 'TWO: ' + sharedService.message;
    });
}

The ControllerOne and ControllerTwo listen message change by using $scope.$on handler.

Android: Create spinner programmatically from array

This worked for me with a string-array named shoes loaded from the projects resources:

Spinner              spinnerCountShoes = (Spinner)findViewById(R.id.spinner_countshoes);
ArrayAdapter<String> spinnerCountShoesArrayAdapter = new ArrayAdapter<String>(
                     this,
                     android.R.layout.simple_spinner_dropdown_item, 
                     getResources().getStringArray(R.array.shoes));
spinnerCountShoes.setAdapter(spinnerCountShoesArrayAdapter);

This is my resource file (res/values/arrays.xml) with the string-array named shoes:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="shoes">
        <item>0</item>
        <item>5</item>
        <item>10</item>
        <item>100</item>
        <item>1000</item>
        <item>10000</item>
    </string-array>
</resources>

With this method it's easier to make it multilingual (if necessary).

Jupyter notebook not running code. Stuck on In [*]

Usually, stopping and restarting that particular cell fixes this issue.

Number of days in particular month of particular year?

In Java8 you can use get ValueRange from a field of a date.

LocalDateTime dateTime = LocalDateTime.now();

ChronoField chronoField = ChronoField.MONTH_OF_YEAR;
long max = dateTime.range(chronoField).getMaximum();

This allows you to parameterize on the field.

Parsing JSON array with PHP foreach

$user->data is an array of objects. Each element in the array has a name and value property (as well as others).

Try putting the 2nd foreach inside the 1st.

foreach($user->data as $mydata)
{
    echo $mydata->name . "\n";
    foreach($mydata->values as $values)
    {
        echo $values->value . "\n";
    }
}

How to run travis-ci locally

tl;dr Use image specified at https://docs.travis-ci.com/user/common-build-problems/#troubleshooting-locally-in-a-docker-image in combination with https://github.com/travis-ci/travis-build#use-as-addon-for-travis-cli.


EDIT 2019-12-06

#troubleshooting-locally-in-a-docker-image section was replaced by #running-builds-in-debug-mode which also describes how to SSH to the job running in the debug mode.

EDIT 2019-07-26

#troubleshooting-locally-in-a-docker-image section is no longer part of the docs; here's why


Though, it's still in git history: https://github.com/travis-ci/docs-travis-ci-com/pull/2193.

Look for (quite old, couldn't find newer) image versions at: https://travis-ci.org/travis-ci/docs-travis-ci-com/builds/230889063#L661.



I wanted to inspect why one of the tests in my build failed with an error I din't get locally.

Worked.

What actually worked was using the image specified at Troubleshooting Locally in a Docker Image docs page. In my case it was travisci/ci-garnet:packer-1512502276-986baf0.

I was able to add travise compile following steps described at https://github.com/travis-ci/travis-build#use-as-addon-for-travis-cli.

dm@z580:~$ docker run --name travis-debug -dit travisci/ci-garnet:packer-1512502276-986baf0 /sbin/init
dm@z580:~$ docker images
REPOSITORY                       TAG                          IMAGE ID            CREATED             SIZE
travisci/ci-garnet               packer-1512502276-986baf0    6cbda6a950d3        11 months ago       10.2GB
dm@z580:~$ docker exec -it travis-debug bash -l
root@912e43dbfea4:/# su - travis
travis@912e43dbfea4:~$ cd builds/
travis@912e43dbfea4:~/builds$ git clone https://github.com/travis-ci/travis-build
travis@912e43dbfea4:~/builds$ cd travis-build
travis@912e43dbfea4:~/builds/travis-build$ mkdir -p ~/.travis
travis@912e43dbfea4:~/builds/travis-build$ ln -s $PWD ~/.travis/travis-build
travis@912e43dbfea4:~/builds/travis-build$ gem install bundler
travis@912e43dbfea4:~/builds/travis-build$ bundle install --gemfile ~/.travis/travis-build/Gemfile
travis@912e43dbfea4:~/builds/travis-build$ bundler binstubs travis
travis@912e43dbfea4:~/builds/travis-build$ cd ..
travis@912e43dbfea4:~/builds$ git clone --depth=50 --branch=master https://github.com/DusanMadar/PySyncDroid.git DusanMadar/PySyncDroid
travis@912e43dbfea4:~/builds$ cd DusanMadar/PySyncDroid/
travis@912e43dbfea4:~/builds/DusanMadar/PySyncDroid$ ~/.travis/travis-build/bin/travis compile > ci.sh
travis@912e43dbfea4:~/builds/DusanMadar/PySyncDroid$ sed -i 's,--branch\\=\\\x27\\\x27,--branch\\=master,g' ci.sh
travis@912e43dbfea4:~/builds/DusanMadar/PySyncDroid$ bash ci.sh

Everything from .travis.yml was executed as expected (dependencies installed, tests ran, ...).

Note that before running bash ci.sh I had to change --branch\=\'\'\ to --branch\=master\ (see the second to last sed -i ... command) in ci.sh.

If that doesn't work the command bellow will help to identify the target line number and you can edit the line manually.

travis@912e43dbfea4:~/builds/DusanMadar/PySyncDroid$ cat ci.sh | grep -in branch
840:    travis_cmd git\ clone\ --depth\=50\ --branch\=\'\'\ https://github.com/DusanMadar/PySyncDroid.git\ DusanMadar/PySyncDroid --echo --retry --timing
889:export TRAVIS_BRANCH=''
899:export TRAVIS_PULL_REQUEST_BRANCH=''
travis@912e43dbfea4:~/builds/DusanMadar/PySyncDroid$

Didn't work.

Followed the accepted answer for this question but didn't find the image (travis-ci-garnet-trusty-1512502259-986baf0) mentioned by instance at https://hub.docker.com/u/travisci/.

Build worker version points to travis-ci/worker commit and its travis-worker-install references quay.io/travisci/ as image registry. So I tried it.

dm@z580:~$ docker run -it -u travis quay.io/travisci/travis-python /bin/bash
travis@370c23a773c9:/$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 12.04.5 LTS
Release:    12.04
Codename:   precise
travis@370c23a773c9:/$
dm@z580:~$ docker images 
REPOSITORY                       TAG                          IMAGE ID            CREATED             SIZE
quay.io/travisci/travis-python   latest                       753a216d776c        3 years ago         5.36GB

Definitely not Trusty (Ubuntu 14.04) and not small either.

Database, Table and Column Naming Conventions?

I'm also in favour of a ISO/IEC 11179 style naming convention, noting they are guidelines rather than being prescriptive.

See Data element name on Wikipedia:

"Tables are Collections of Entities, and follow Collection naming guidelines. Ideally, a collective name is used: eg., Personnel. Plural is also correct: Employees. Incorrect names include: Employee, tblEmployee, and EmployeeTable."

As always, there are exceptions to rules e.g. a table which always has exactly one row may be better with a singular name e.g. a config table. And consistency is of utmost importance: check whether you shop has a convention and, if so, follow it; if you don't like it then do a business case to have it changed rather than being the lone ranger.

How to fix nginx throws 400 bad request headers on any header testing tools?

Yes changing the error_to debug level as Emmanuel Joubaud suggested worked out (edit /etc/nginx/sites-enabled/default ):

        error_log /var/log/nginx/error.log debug;

Then after restaring nginx I got in the error log with my Python application using uwsgi:

        2017/02/08 22:32:24 [debug] 1322#1322: *1 connect to unix:///run/uwsgi/app/socket, fd:20 #2
        2017/02/08 22:32:24 [debug] 1322#1322: *1 connected
        2017/02/08 22:32:24 [debug] 1322#1322: *1 http upstream connect: 0
        2017/02/08 22:32:24 [debug] 1322#1322: *1 posix_memalign: 0000560E1F25A2A0:128 @16
        2017/02/08 22:32:24 [debug] 1322#1322: *1 http upstream send request
        2017/02/08 22:32:24 [debug] 1322#1322: *1 http upstream send request body
        2017/02/08 22:32:24 [debug] 1322#1322: *1 chain writer buf fl:0 s:454
        2017/02/08 22:32:24 [debug] 1322#1322: *1 chain writer in: 0000560E1F2A0928
        2017/02/08 22:32:24 [debug] 1322#1322: *1 writev: 454 of 454
        2017/02/08 22:32:24 [debug] 1322#1322: *1 chain writer out: 0000000000000000
        2017/02/08 22:32:24 [debug] 1322#1322: *1 event timer add: 20: 60000:1486593204249
        2017/02/08 22:32:24 [debug] 1322#1322: *1 http finalize request: -4, "/?" a:1, c:2
        2017/02/08 22:32:24 [debug] 1322#1322: *1 http request count:2 blk:0
        2017/02/08 22:32:24 [debug] 1322#1322: *1 post event 0000560E1F2E5DE0
        2017/02/08 22:32:24 [debug] 1322#1322: *1 post event 0000560E1F2E5E40
        2017/02/08 22:32:24 [debug] 1322#1322: *1 delete posted event 0000560E1F2E5DE0
        2017/02/08 22:32:24 [debug] 1322#1322: *1 http run request: "/?"
        2017/02/08 22:32:24 [debug] 1322#1322: *1 http upstream check client, write event:1, "/"
        2017/02/08 22:32:24 [debug] 1322#1322: *1 http upstream recv(): -1 (11: Resource temporarily unavailable)

Then I took a look to my uwsgi log and found out that:

        Invalid HTTP_HOST header: 'www.mysite.local'. You may need to add u'www.mysite.local' to ALLOWED_HOSTS.
        [pid: 10903|app: 0|req: 2/4] 192.168.221.2 () {38 vars in 450 bytes} [Wed Feb  8 22:32:24 2017] GET / => generated 54098 bytes in 55 msecs (HTTP/1.1 400) 4 headers in 135 bytes (1 switches on core 0)

And adding www.mysite.local to the settings.py ALLOWED_HOSTS fixed the issue :)

        ALLOWED_HOSTS = ['www.mysite.local']

Double vs. BigDecimal?

If you write down a fractional value like 1 / 7 as decimal value you get

1/7 = 0.142857142857142857142857142857142857142857...

with an infinite sequence of 142857. Since you can only write a finite number of digits you will inevitably introduce a rounding (or truncation) error.

Numbers like 1/10 or 1/100 expressed as binary numbers with a fractional part also have an infinite number of digits after the decimal point:

1/10 = binary 0.0001100110011001100110011001100110...

Doubles store values as binary and therefore might introduce an error solely by converting a decimal number to a binary number, without even doing any arithmetic.

Decimal numbers (like BigDecimal), on the other hand, store each decimal digit as is (binary coded, but each decimal on its own). This means that a decimal type is not more precise than a binary floating point or fixed point type in a general sense (i.e. it cannot store 1/7 without loss of precision), but it is more accurate for numbers that have a finite number of decimal digits as is often the case for money calculations.

Java's BigDecimal has the additional advantage that it can have an arbitrary (but finite) number of digits on both sides of the decimal point, limited only by the available memory.

ps command doesn't work in docker container

use docker top

docker top <container ID>

Best way to parseDouble with comma as decimal separator?

If you don't know the correct Locale and the string can have a thousand separator this could be a last resort:

    doubleStrIn = doubleStrIn.replaceAll("[^\\d,\\.]++", "");
    if (doubleStrIn.matches(".+\\.\\d+,\\d+$"))
        return Double.parseDouble(doubleStrIn.replaceAll("\\.", "").replaceAll(",", "."));
    if (doubleStrIn.matches(".+,\\d+\\.\\d+$"))
        return Double.parseDouble(doubleStrIn.replaceAll(",", ""));
    return Double.parseDouble(doubleStrIn.replaceAll(",", "."));

Be aware: this will happily parse strings like "R 1 52.43,2" to "15243.2".

how to make password textbox value visible when hover an icon

<html>
<head>
</head>
<body>
<script>
function demo(){
    var d=document.getElementById('s1');
    var e=document.getElementById('show_f').value;
    var f=document.getElementById('show_f').type; 

    if(d.value=="show"){
        var f= document.getElementById('show_f').type="text";
        var g=document.getElementById('show_f').value=e;
        d.value="Hide";

    } else{
        var f= document.getElementById('show_f').type="password";
        var g=document.getElementById('show_f').value=e;
        d.value="show";
     }     
  }   
</script>   

<form method='post'>
Password: <input type='password' name='pass_f' maxlength='30' id='show_f'><input type="button" onclick="demo()" id="s1" value="show" style="height:25px; margin-left:5px;margin-top:3px;"><br><br>
<input type='submit' name='sub' value='Submit Now'>

</form>
</body>
</html>

C# constructors overloading

Maybe your class isn't quite complete. Personally, I use a private init() function with all of my overloaded constructors.

class Point2D {

  double X, Y;

  public Point2D(double x, double y) {
    init(x, y);
  }

  public Point2D(Point2D point) {
    if (point == null)
      throw new ArgumentNullException("point");
    init(point.X, point.Y);
  }

  void init(double x, double y) {
    // ... Contracts ...
    X = x;
    Y = y;
  }
}

Syntax error near unexpected token 'fi'

"Then" is a command in bash, thus it needs a ";" or a newline before it.

#!/bin/bash
echo "start\n"
for f in *.jpg
do
  fname=$(basename "$f")
  echo "fname is $fname\n"
  fname="${filename%.*}"
  echo "fname is $fname\n"
  if [$[fname%2] -eq 1 ]
  then
    echo "removing $fname\n"
    rm $f
  fi
done

First char to upper case

Or you can do

s = Character.toUpperCase(s.charAt(0)) + s.substring(1); 

PHP: convert spaces in string into %20?

Use the rawurlencode function instead.

JsonParseException : Illegal unquoted character ((CTRL-CHAR, code 10)

Using

mapper.configure(
    JsonReadFeature.ALLOW_UNESCAPED_CONTROL_CHARS.mappedFeature(), 
    true
);

See javadoc:

/**
 * Feature that determines whether parser will allow
 * JSON Strings to contain unescaped control characters
 * (ASCII characters with value less than 32, including
 * tab and line feed characters) or not.
 * If feature is set false, an exception is thrown if such a
 * character is encountered.
 *<p>
 * Since JSON specification requires quoting for all control characters,
 * this is a non-standard feature, and as such disabled by default.
 */

Old option JsonParser.Feature.ALLOW_UNQUOTED_CONTROL_CHARS was deprecated since 2.10.

Please see also github thread.

Access props inside quotes in React JSX

Here is the Best Option for Dynamic className or Props , just do some concatenation like we do in Javascript.

     className={
        "badge " +
        (this.props.value ? "badge-primary " : "badge-danger ") +
        " m-4"
      }

How do I properly set the Datetimeindex for a Pandas datetime object in a dataframe?

You are not creating datetime index properly,

format = '%Y-%m-%d %H:%M:%S'
df['Datetime'] = pd.to_datetime(df['date'] + ' ' + df['time'], format=format)
df = df.set_index(pd.DatetimeIndex(df['Datetime']))

How to retrieve element value of XML using Java?

If your XML is a String, Then you can do the following:

String xml = ""; //Populated XML String....

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(new InputSource(new StringReader(xml)));
Element rootElement = document.getDocumentElement();

If your XML is in a file, then Document document will be instantiated like this:

Document document = builder.parse(new File("file.xml"));

The document.getDocumentElement() returns you the node that is the document element of the document (in your case <config>).

Once you have a rootElement, you can access the element's attribute (by calling rootElement.getAttribute() method), etc. For more methods on java's org.w3c.dom.Element

More info on java DocumentBuilder & DocumentBuilderFactory. Bear in mind, the example provided creates a XML DOM tree so if you have a huge XML data, the tree can be huge.


Update Here's an example to get "value" of element <requestqueue>

protected String getString(String tagName, Element element) {
        NodeList list = element.getElementsByTagName(tagName);
        if (list != null && list.getLength() > 0) {
            NodeList subList = list.item(0).getChildNodes();

            if (subList != null && subList.getLength() > 0) {
                return subList.item(0).getNodeValue();
            }
        }

        return null;
    }

You can effectively call it as,

String requestQueueName = getString("requestqueue", element);

Show all current locks from get_lock

From MySQL 5.7 onwards, this is possible, but requires first enabling the mdl instrument in the performance_schema.setup_instruments table. You can do this temporarily (until the server is next restarted) by running:

UPDATE performance_schema.setup_instruments
SET enabled = 'YES'
WHERE name = 'wait/lock/metadata/sql/mdl';

Or permanently, by adding the following incantation to the [mysqld] section of your my.cnf file (or whatever config files MySQL reads from on your installation):

[mysqld]
performance_schema_instrument = 'wait/lock/metadata/sql/mdl=ON'

(Naturally, MySQL will need to be restarted to make the config change take effect if you take the latter approach.)

Locks you take out after the mdl instrument has been enabled can be seen by running a SELECT against the performance_schema.metadata_locks table. As noted in the docs, GET_LOCK locks have an OBJECT_TYPE of 'USER LEVEL LOCK', so we can filter our query down to them with a WHERE clause:

mysql> SELECT GET_LOCK('foobarbaz', -1);
+---------------------------+
| GET_LOCK('foobarbaz', -1) |
+---------------------------+
|                         1 |
+---------------------------+
1 row in set (0.00 sec)

mysql> SELECT * FROM performance_schema.metadata_locks 
    -> WHERE OBJECT_TYPE='USER LEVEL LOCK'
    -> \G
*************************** 1. row ***************************
          OBJECT_TYPE: USER LEVEL LOCK
        OBJECT_SCHEMA: NULL
          OBJECT_NAME: foobarbaz
OBJECT_INSTANCE_BEGIN: 139872119610944
            LOCK_TYPE: EXCLUSIVE
        LOCK_DURATION: EXPLICIT
          LOCK_STATUS: GRANTED
               SOURCE: item_func.cc:5482
      OWNER_THREAD_ID: 35
       OWNER_EVENT_ID: 3
1 row in set (0.00 sec)

mysql> 

The meanings of the columns in this result are mostly adequately documented at https://dev.mysql.com/doc/refman/en/metadata-locks-table.html, but one point of confusion is worth noting: the OWNER_THREAD_ID column does not contain the connection ID (like would be shown in the PROCESSLIST or returned by CONNECTION_ID()) of the thread that holds the lock. Confusingly, the term "thread ID" is sometimes used as a synonym of "connection ID" in the MySQL documentation, but this is not one of those times. If you want to determine the connection ID of the connection that holds a lock (for instance, in order to kill that connection with KILL), you'll need to look up the PROCESSLIST_ID that corresponds to the THREAD_ID in the performance_schema.threads table. For instance, to kill the connection that was holding my lock above...

mysql> SELECT OWNER_THREAD_ID FROM performance_schema.metadata_locks
    -> WHERE OBJECT_TYPE='USER LEVEL LOCK'
    -> AND OBJECT_NAME='foobarbaz';
+-----------------+
| OWNER_THREAD_ID |
+-----------------+
|              35 |
+-----------------+
1 row in set (0.00 sec)

mysql> SELECT PROCESSLIST_ID FROM performance_schema.threads
    -> WHERE THREAD_ID=35;
+----------------+
| PROCESSLIST_ID |
+----------------+
|             10 |
+----------------+
1 row in set (0.00 sec)

mysql> KILL 10;
Query OK, 0 rows affected (0.00 sec)

java.lang.NoClassDefFoundError in junit

On Eclipse I was able to solve the above issue by following the below steps :

Right-click on the test file which you want to run, Select Run As -> Run Configurations -> Select Classpath tab -> Select to the bootstrap Entries -> Select Advanced -> Select Add library -> Select JUnit -> Next ->Select JUnit4 from the drop-down -> Finish

Then Select Apply -> Run

Array of Matrices in MATLAB

if you know what unknown is,

you can do something like

myArray = zeros(2,2);
for i: 1:unknown
  myArray(:,i) = zeros(x,y);
end

However it has been a while since I last used matlab. so this page might shed some light on the matter :

http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/access/helpdesk/help/techdoc/matlab_prog/f1-86528.html

git pull from master into the development branch

Scenario:

I have master updating and my branch updating, I want my branch to keep track of master with rebasing, to keep all history tracked properly, let's call my branch Mybranch

Solution:

git checkout master    
git pull --rebase    
git checkout Mybranch    
git rebase master
git push -f origin Mybranch
  • need to resolve all conflicts with git mergetool &, git rebase --continue, git rebase --skip, git add -u, according to situation and git hints, till all is solved

(correction to last stage, in courtesy of Tzachi Cohen, using "-f" forces git to "update history" at server)

now branch should be aligned with master and rebased, also with remote updated, so at git log there are no "behind" or "ahead", just need to remove all local conflict *.orig files to keep folder "clean"

How to handle onchange event on input type=file in jQuery?

Or could be:

$('input[type=file]').change(function () {
    alert("hola");
});

To be specific: $('input[type=file]#fileUpload1').change(...

Get records of current month

Check the MySQL Datetime Functions:

Try this:

SELECT * 
FROM tableA 
WHERE YEAR(columnName) = YEAR(CURRENT_DATE()) AND 
      MONTH(columnName) = MONTH(CURRENT_DATE());

Database corruption with MariaDB : Table doesn't exist in engine

This theme required awhile to find results and reasons:

using MaiaDB 5.4. via SuSE-LINUX tumblweed

  1. some files in the appointed directory havn't been necessary in any direct relation with mariadb. I.e: I placed some hints, a text-file, some bakup-copys somewhere in the same appointed directory for mysql mariadb and this caused endless error-messages and blocking the server from starting. Mariadb appears to be very sensible and hostile with the presence of other files not beeing database files(comments,backups,experimantal files etc) .

  2. using libreoffice as client then there already this generated much problems with the creation and working on a database and caused some crashes.The crashes eventually produced bad tables.

  3. May be because of that or may be because of the presence of not yet deleted but unusable tables !! the mysql mariadb server crashed and didn't want to do it' job not even start.

Error message always same : "Table 'some.table' doesn't exist in engine"

But when it started then tables appeared as normal, but it was unpossible to work on them.

So what to do without a more precise Error Message ?? The unusable tables showed up with: "CHECK TABLE" or on the command line of the system with "mysqlcheck " So I deleted by filemanager or on the system-level as root or as allowed user all the questionable files and then problem was solved.

Proposal: the Error Message could be a bit more precisely for example: "corrupted tables" (which can be found by CHECK TABLE, but only if the server is running) or by mysqlcheck even whe server is not running - but here are other disturbing files like hints/bakups a.s.o not visible.

ANYWAY it helped a lot to have backup-copies of the original database-files on a backup volume. This helped to check out and test it again and again until solution was found.

Good luck all - Herbert