Programs & Examples On #Buildr

A build tool for Java, Scala, Groovy, and other JVM-based projects.

Android Gradle 5.0 Update:Cause: org.jetbrains.plugins.gradle.tooling.util

Issue has been resolved after updating Android studio version to 3.3-rc2 or latest released version.

cr: @shadowsheep

have to change version under /gradle/wrapper/gradle-wrapper.properties. refer below url https://stackoverflow.com/a/56412795/7532946

Visual Studio debugging/loading very slow

Similar problem wasted better half of my day!

Since solution for my problem was different from whats said here, I'm going to post it so it might help someone else.

Mine was a breakpoint. I had a "Break at function" breakpoint (i.e instead of pressing F9 on a code line, we create them using the breakpoints window) which is supposed to stop in a library function outside my project.

And I had "Use Intellisense to verify the function name" CHECKED. (Info here.)

This slowed down vs like hell (project start-up from 2 seconds to 5 minutes).

Removing the break point solved it for good.

Linux configure/make, --prefix?

In my situation, --prefix= failed to update the path correctly under some warnings or failures. please see the below link for the answer. https://stackoverflow.com/a/50208379/1283198

Java: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

Quoting from No more 'unable to find valid certification path to requested target'

when trying to open an SSL connection to a host using JSSE. What this usually means is that the server is using a test certificate (possibly generated using keytool) rather than a certificate from a well known commercial Certification Authority such as Verisign or GoDaddy. Web browsers display warning dialogs in this case, but since JSSE cannot assume an interactive user is present it just throws an exception by default.

Certificate validation is a very important part of SSL security, but I am not writing this entry to explain the details. If you are interested, you can start by reading the Wikipedia blurb. I am writing this entry to show a simple way to talk to that host with the test certificate, if you really want to.

Basically, you want to add the server's certificate to the KeyStore with your trusted certificates

Try the code provided there. It might help.

Uncaught SyntaxError: Unexpected token :

Just an FYI for people who might have the same problem -- I just had to make my server send back the JSON as application/json and the default jQuery handler worked fine.

Could not load file or assembly 'System.Data.SQLite'

Can you delete your bin debug folder and recompile again?

Or check your project reference to the System.Data.SQLite, track down where it is located, then open the dll in reflector. If you can't open it, that means that the dll is corrupted, you might want to find a correct one or reinstall the .net framework.

Disable Logback in SpringBoot

This worked for me just fine

configurations {
    all*.exclude module : 'spring-boot-starter-logging'
}

But it wouldn't work out for maven users. All my dependencies was in libs.gradle and I didn't want them in other files. So this problem was solved by adding exclude module : 'spring-boot-starter-logging in spring-boot-starter-data-jpa, spring-boot-starter-test and in practically everything with boot word.

UPDATE

New project of mine needed an update, turns out spring-boot-starter-test 1.5 and older didn't have spring-boot-starter-logging. 2.0 has it

How to add new column to an dataframe (to the front not end)?

cbind inherents order by its argument order.

User your first column(s) as your first argument

cbind(fst_col , df)

  fst_col   df_col1   df_col2
1 0             0.2      -0.1
2 0             0.2      -0.1
3 0             0.2      -0.1
4 0             0.2      -0.1
5 0             0.2      -0.1

cbind(df, last_col)

  df_col1   df_col2  last_col
1 0.2      -0.1             0
2 0.2      -0.1             0
3 0.2      -0.1             0
4 0.2      -0.1             0
5 0.2      -0.1             0

Accessing the web page's HTTP Headers in JavaScript

As has already been mentioned, if you control the server side then it should be possible to send the initial request headers back to the client in the initial response.

In Express, for example, the following works:

app.get('/somepage', (req, res) => { res.render('somepage.hbs', {headers: req.headers}); }) The headers are then available within the template, so could be hidden visually but included in the markup and read by clientside javascript.

Android Studio: Plugin with id 'android-library' not found

Use mavenCentral() or jcenter() adding in the build.gradle file the script:

buildscript {
    repositories {
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:1.5.0'   
    }
}

Android Get Current timestamp?

Solution in Kotlin:

val nowInEpoch = Instant.now().epochSecond

Make sure your minimum SDK version is 26.

What is an HttpHandler in ASP.NET

Any Class that implements System.Web.IHttpHandler Interface becomes HttpHandler. And this class run as processes in response to a request made to the ASP.NET Site.

The most common handler is an ASP.NET page handler that processes .aspx files. When users request an .aspx file, the request is processed by the page through the page handler(The Class that implements System.Web.IHttpHandler Interface).

You can create your own custom HTTP handlers that render custom output to the browser.

Some ASP.NET default handlers are:

  1. Page Handler (.aspx) – Handles Web pages
  2. User Control Handler (.ascx) – Handles Web user control pages
  3. Web Service Handler (.asmx) – Handles Web service pages
  4. Trace Handler (trace.axd) – Handles trace functionality

How to solve the memory error in Python

Assuming your example text is representative of all the text, one line would consume about 75 bytes on my machine:

In [3]: sys.getsizeof('usedfor zipper fasten_coat')
Out[3]: 75

Doing some rough math:

75 bytes * 8,000,000 lines / 1024 / 1024 = ~572 MB

So roughly 572 meg to store the strings alone for one of these files. Once you start adding in additional, similarly structured and sized files, you'll quickly approach your virtual address space limits, as mentioned in @ShadowRanger's answer.

If upgrading your python isn't feasible for you, or if it only kicks the can down the road (you have finite physical memory after all), you really have two options: write your results to temporary files in-between loading in and reading the input files, or write your results to a database. Since you need to further post-process the strings after aggregating them, writing to a database would be the superior approach.

How to deal with persistent storage (e.g. databases) in Docker

My solution is to get use of the new docker cp, which is now able to copy data out from containers, not matter if it's running or not and share a host volume to the exact same location where the database application is creating its database files inside the container. This double solution works without a data-only container, straight from the original database container.

So my systemd init script is taking the job of backuping the database into an archive on the host. I placed a timestamp in the filename to never rewrite a file.

It's doing it on the ExecStartPre:

ExecStartPre=-/usr/bin/docker cp lanti-debian-mariadb:/var/lib/mysql /home/core/sql
ExecStartPre=-/bin/bash -c '/usr/bin/tar -zcvf /home/core/sql/sqlbackup_$$(date +%%Y-%%m-%%d_%%H-%%M-%%S)_ExecStartPre.tar.gz /home/core/sql/mysql --remove-files'

And it is doing the same thing on ExecStopPost too:

ExecStopPost=-/usr/bin/docker cp lanti-debian-mariadb:/var/lib/mysql /home/core/sql
ExecStopPost=-/bin/bash -c 'tar -zcvf /home/core/sql/sqlbackup_$$(date +%%Y-%%m-%%d_%%H-%%M-%%S)_ExecStopPost.tar.gz /home/core/sql/mysql --remove-files'

Plus I exposed a folder from the host as a volume to the exact same location where the database is stored:

mariadb:
  build: ./mariadb
  volumes:
    - $HOME/server/mysql/:/var/lib/mysql/:rw

It works great on my VM (I building a LEMP stack for myself): https://github.com/DJviolin/LEMP

But I just don't know if is it a "bulletproof" solution when your life depends on it actually (for example, webshop with transactions in any possible miliseconds)?

At 20 min 20 secs from this official Docker keynote video, the presenter does the same thing with the database:

Getting Started with Docker

"For the database we have a volume, so we can make sure that, as the database goes up and down, we don't loose data, when the database container stopped."

SVN Repository Search

theres krugle and koders but both are expensive. Both have ide plugins for eclipse.

How to create a collapsing tree table in html/css/js?

I'll throw jsTree into the ring, too. I've found it fairly adaptable to your particular situation. It's packed as a jQuery plugin.

It can run from a variety of data sources, but my favorite is a simple nested list, as described by @joe_coolish or here:

<ul>
  <li>
    Item 1
    <ul>
      <li>Item 1.1</li>
      ...
    </ul>
  </li>
  ...
</ul>

This structure fails gracefully into a static tree when JS is not available in the client, and is easy enough to read and understand from a coding perspective.

The difference between fork(), vfork(), exec() and clone()

The fork(),vfork() and clone() all call the do_fork() to do the real work, but with different parameters.

asmlinkage int sys_fork(struct pt_regs regs)
{
    return do_fork(SIGCHLD, regs.esp, &regs, 0);
}

asmlinkage int sys_clone(struct pt_regs regs)
{
    unsigned long clone_flags;
    unsigned long newsp;

    clone_flags = regs.ebx;
    newsp = regs.ecx;
    if (!newsp)
        newsp = regs.esp;
    return do_fork(clone_flags, newsp, &regs, 0);
}
asmlinkage int sys_vfork(struct pt_regs regs)
{
    return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, &regs, 0);
}
#define CLONE_VFORK 0x00004000  /* set if the parent wants the child to wake it up on mm_release */
#define CLONE_VM    0x00000100  /* set if VM shared between processes */

SIGCHLD means the child should send this signal to its father when exit.

For fork, the child and father has the independent VM page table, but since the efficiency, fork will not really copy any pages, it just set all the writeable pages to readonly for child process. So when child process want to write something on that page, an page exception happen and kernel will alloc a new page cloned from the old page with write permission. That's called "copy on write".

For vfork, the virtual memory is exactly by child and father---just because of that, father and child can't be awake concurrently since they will influence each other. So the father will sleep at the end of "do_fork()" and awake when child call exit() or execve() since then it will own new page table. Here is the code(in do_fork()) that the father sleep.

if ((clone_flags & CLONE_VFORK) && (retval > 0))
down(&sem);
return retval;

Here is the code(in mm_release() called by exit() and execve()) which awake the father.

up(tsk->p_opptr->vfork_sem);

For sys_clone(), it is more flexible since you can input any clone_flags to it. So pthread_create() call this system call with many clone_flags:

int clone_flags = (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGNAL | CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID | CLONE_SYSVSEM);

Summary: the fork(),vfork() and clone() will create child processes with different mount of sharing resource with the father process. We also can say the vfork() and clone() can create threads(actually they are processes since they have independent task_struct) since they share the VM page table with father process.

c# Best Method to create a log file

I would not use third party libraries, I would log to an xml file.

This is a code sample that do logging to a xml file from different threads:

private static readonly object Locker = new object();
private static XmlDocument _doc = new XmlDocument();

static void Main(string[] args)
{
    if (File.Exists("logs.txt"))
        _doc.Load("logs.txt");
    else
    {
        var root = _doc.CreateElement("hosts");
        _doc.AppendChild(root);
    }

    for (int i = 0; i < 100; i++)
    {
        new Thread(new ThreadStart(DoSomeWork)).Start();
    }
}

static void DoSomeWork()
{
    /*
     * Here you will build log messages
     */
    Log("192.168.1.15", "alive");
}

static void Log(string hostname, string state)
{
    lock (Locker)
    {
        var el = (XmlElement)_doc.DocumentElement.AppendChild(_doc.CreateElement("host"));
        el.SetAttribute("Hostname", hostname);
        el.AppendChild(_doc.CreateElement("State")).InnerText = state;
        _doc.Save("logs.txt");
    }
}

Generating all permutations of a given string

public static void permutation(String str) { 
    permutation("", str); 
}

private static void permutation(String prefix, String str) {
    int n = str.length();
    if (n == 0) System.out.println(prefix);
    else {
        for (int i = 0; i < n; i++)
            permutation(prefix + str.charAt(i), str.substring(0, i) + str.substring(i+1, n));
    }
}

(via Introduction to Programming in Java)

Bash script error [: !=: unary operator expected

Or for what seems like rampant overkill, but is actually simplistic ... Pretty much covers all of your cases, and no empty string or unary concerns.

In the case the first arg is '-v', then do your conditional ps -ef, else in all other cases throw the usage.

#!/bin/sh
case $1 in
  '-v') if [ "$1" = -v ]; then
         echo "`ps -ef | grep -v '\['`"
        else
         echo "`ps -ef | grep '\[' | grep root`"
        fi;;
     *) echo "usage: $0 [-v]"
        exit 1;; #It is good practice to throw a code, hence allowing $? check
esac

If one cares not where the '-v' arg is, then simply drop the case inside a loop. The would allow walking all the args and finding '-v' anywhere (provided it exists). This means command line argument order is not important. Be forewarned, as presented, the variable arg_match is set, thus it is merely a flag. It allows for multiple occurrences of the '-v' arg. One could ignore all other occurrences of '-v' easy enough.

#!/bin/sh

usage ()
 {
  echo "usage: $0 [-v]"
  exit 1
 }

unset arg_match

for arg in $*
 do
  case $arg in
    '-v') if [ "$arg" = -v ]; then
           echo "`ps -ef | grep -v '\['`"
          else
           echo "`ps -ef | grep '\[' | grep root`"
          fi
          arg_match=1;; # this is set, but could increment.
       *) ;;
  esac
done

if [ ! $arg_match ]
 then
  usage
fi

But, allow multiple occurrences of an argument is convenient to use in situations such as:

$ adduser -u:sam -s -f -u:bob -trace -verbose

We care not about the order of the arguments, and even allow multiple -u arguments. Yes, it is a simple matter to also allow:

$ adduser -u sam -s -f -u bob -trace -verbose

Explanation of JSONB introduced by PostgreSQL

Another important difference, that wasn't mentioned in any answer above, is that there is no equality operator for json type, but there is one for jsonb.

This means that you can't use DISTINCT keyword when selecting this json-type and/or other fields from a table (you can use DISTINCT ON instead, but it's not always possible because of cases like this).

C free(): invalid pointer

From where did you get the idea that you need to free(token) and free(tk)? You don't. strsep() doesn't allocate memory, it only returns pointers inside the original string. Of course, those are not pointers allocated by malloc() (or similar), so free()ing them is undefined behavior. You only need to free(s) when you are done with the entire string.

Also note that you don't need dynamic memory allocation at all in your example. You can avoid strdup() and free() altogether by simply writing char *s = p;.

Using comma as list separator with AngularJS

Also:

angular.module('App.filters', [])
    .filter('joinBy', function () {
        return function (input,delimiter) {
            return (input || []).join(delimiter || ',');
        };
    });

And in template:

{{ itemsArray | joinBy:',' }}

JavaScript error: "is not a function"

Your LMSInitialize function is declared inside Scorm_API_12 function. So it can be seen only in Scorm_API_12 function's scope.

If you want to use this function like API.LMSInitialize(""), declare Scorm_API_12 function like this:

function Scorm_API_12() {
var Initialized = false;

this.LMSInitialize = function(param) {
    errorCode = "0";
    if (param == "") {
        if (!Initialized) {
            Initialized = true;
            errorCode = "0";
            return "true";
        } else {
            errorCode = "101";
        }
    } else {
        errorCode = "201";
    }
    return "false";
}

// some more functions, omitted.
}

var API = new Scorm_API_12();

Is there a way I can capture my iPhone screen as a video?

I've continued to research this item myself, and it does appear to remain beyond us at this point.

I even tried buying a Apple Composite AV Cable, but it doesn't capture screen, just video playing like YouTube, etc.

So I decided to go with the iShowU path and that has worked out well so far.

Thanks Guys!

Subset data.frame by date

The first thing you should do with date variables is confirm that R reads it as a Date. To do this, for the variable (i.e. vector/column) called Date, in the data frame called EPL2011_12, input

class(EPL2011_12$Date)

The output should read [1] "Date". If it doesn't, you should format it as a date by inputting

EPL2011_12$Date <- as.Date(EPL2011_12$Date, "%d-%m-%y")

Note that the hyphens in the date format ("%d-%m-%y") above can also be slashes ("%d/%m/%y"). Confirm that R sees it as a Date. If it doesn't, try a different formatting command

EPL2011_12$Date <- format(EPL2011_12$Date, format="%d/%m/%y")

Once you have it in Date format, you can use the subset command, or you can use brackets

WhateverYouWant <- EPL2011_12[EPL2011_12$Date > as.Date("2014-12-15"),]

ActionController::InvalidAuthenticityToken

If you have done a rake rails:update or otherwise recently changed your config/initializers/session_store.rb, this may be a symptom of old cookies in the browser. Hopefully this is done in dev/test (it was for me), and you can just clear all browser cookies related to the domain in question.

If this is in production, and you changed key, consider changing it back to use the old cookies (<- just speculation).

How to left align a fixed width string?

This one worked in my python script:

print "\t%-5s %-10s %-10s %-10s %-10s %-10s %-20s"  % (thread[0],thread[1],thread[2],thread[3],thread[4],thread[5],thread[6])

Install Chrome extension form outside the Chrome Web Store

For regular Windows users who are not skilled with computers, it is practically not possible to install and use extensions from outside the Chrome Web Store.

Users of other operating systems (Linux, Mac, Chrome OS) can easily install unpacked extensions (in developer mode).
Windows users can also load an unpacked extension, but they will always see an information bubble with "Disable developer mode extensions" when they start Chrome or open a new incognito window, which is really annoying. The only way for Windows users to use unpacked extensions without such dialogs is to switch to Chrome on the developer channel, by installing https://www.google.com/chrome/browser/index.html?extra=devchannel#eula.

Extensions can be loaded in unpacked mode by following the following steps:

  1. Visit chrome://extensions (via omnibox or menu -> Tools -> Extensions).
  2. Enable Developer mode by ticking the checkbox in the upper-right corner.
  3. Click on the "Load unpacked extension..." button.
  4. Select the directory containing your unpacked extension.

If you have a crx file, then it needs to be extracted first. CRX files are zip files with a different header. Any capable zip program should be able to open it. If you don't have such a program, I recommend 7-zip.

These steps will work for almost every extension, except extensions that rely on their extension ID. If you use the previous method, you will get an extension with a random extension ID. If it is important to preserve the extension ID, then you need to know the public key of your CRX file and insert this in your manifest.json. I have previously given a detailed explanation on how to get and use this key at https://stackoverflow.com/a/21500707.

JQuery html() vs. innerHTML

Here is some code to get you started. You can modify the behavior of .innerHTML -- you could even create your own complete .innerHTML shim. (P.S.: redefining .innerHTML will also work in Firefox, but not Chrome -- they're working on it.)

if (/(msie|trident)/i.test(navigator.userAgent)) {
 var innerhtml_get = Object.getOwnPropertyDescriptor(HTMLElement.prototype, "innerHTML").get
 var innerhtml_set = Object.getOwnPropertyDescriptor(HTMLElement.prototype, "innerHTML").set
 Object.defineProperty(HTMLElement.prototype, "innerHTML", {
  get: function () {return innerhtml_get.call (this)},
  set: function(new_html) {
   var childNodes = this.childNodes
   for (var curlen = childNodes.length, i = curlen; i > 0; i--) {
    this.removeChild (childNodes[0])
   }
   innerhtml_set.call (this, new_html)
  }
 })
}

var mydiv = document.createElement ('div')
mydiv.innerHTML = "test"
document.body.appendChild (mydiv)

document.body.innerHTML = ""
console.log (mydiv.innerHTML)

http://jsfiddle.net/DLLbc/9/

Correct way to use get_or_create?

get_or_create() returns a tuple:

customer.source, created  = Source.objects.get_or_create(name="Website")
  • created ? has a boolean value, is created or not.

  • customer.source ? has an object of get_or_create() method.

Displaying the Error Messages in Laravel after being Redirected from controller

Move all that in kernel.php if just the above method didn't work for you remember you have to move all those lines in kernel.php in addition to the above solution

let me first display the way it is there in the file already..

protected $middleware = [

    \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class,
];

/**
 * The application's route middleware groups.
 *
 * @var array
 */
protected $middlewareGroups = [
    'web' => [
        \App\Http\Middleware\EncryptCookies::class,
        \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
        \Illuminate\Session\Middleware\StartSession::class,
        \Illuminate\View\Middleware\ShareErrorsFromSession::class,
        \App\Http\Middleware\VerifyCsrfToken::class,
    ],

    'api' => [
        'throttle:60,1',
    ],
];

now what you have to do is

protected $middleware = [
    \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class,
     \App\Http\Middleware\EncryptCookies::class,
        \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
        \Illuminate\Session\Middleware\StartSession::class,
        \Illuminate\View\Middleware\ShareErrorsFromSession::class,
        \App\Http\Middleware\VerifyCsrfToken::class,
];

/**
 * The application's route middleware groups.
 *
 * @var array
 */
protected $middlewareGroups = [
    'web' => [

    ],

    'api' => [
        'throttle:60,1',
    ],
];

i.e.;

enter image description here

Gulp error: The following tasks did not complete: Did you forget to signal async completion?

For those who are trying to use gulp for swagger local deployment, following code will help

var gulp = require("gulp");
var yaml = require("js-yaml");
var path = require("path");
var fs = require("fs");

//Converts yaml to json
gulp.task("swagger", done => {
    var doc = yaml.safeLoad(fs.readFileSync(path.join(__dirname,"api/swagger/swagger.yaml")));
    fs.writeFileSync(
        path.join(__dirname,"../yourjsonfile.json"),
        JSON.stringify(doc, null, " ")
        );
    done();
});

//Watches for changes    
gulp.task('watch', function() {
  gulp.watch('api/swagger/swagger.yaml', gulp.series('swagger'));  
});

static files with express.js

res.sendFile & express.static both will work for this

var express = require('express');
var app = express();
var path = require('path');
var public = path.join(__dirname, 'public');

// viewed at http://localhost:8080
app.get('/', function(req, res) {
    res.sendFile(path.join(public, 'index.html'));
});

app.use('/', express.static(public));

app.listen(8080);

Where public is the folder in which the client side code is

As suggested by @ATOzTOA and clarified by @Vozzie, path.join takes the paths to join as arguments, the + passes a single argument to path.

angular.min.js.map not found, what is it exactly?

Monkey is right, according to the link given by monkey

Basically it's a way to map a combined/minified file back to an unbuilt state. When you build for production, along with minifying and combining your JavaScript files, you generate a source map which holds information about your original files. When you query a certain line and column number in your generated JavaScript you can do a lookup in the source map which returns the original location.

I am not sure if it is angular's fault that no map files were generated. But you can turn off source map files by unchecking this option in chrome console setting

enter image description here

How to handle a lost KeyStore password in Android?

Go to taskhistory.bin in .gradle folder of your project search password scroll down till you find the password

Dropdownlist validation in Asp.net Using Required field validator

I was struggling with this for a few days until I chanced on the issue when I had to build a new Dropdown. I had several DropDownList controls and attempted to get validation working with no luck. One was databound and the other was filled from the aspx page. I needed to drop the databound one and add a second manual list. In my case Validators failed if you built a dropdown like this and looked at any value (0 or -1) for either a required or compare validator:

<asp:DropDownList ID="DDL_Reason" CssClass="inputDropDown" runat="server">
<asp:ListItem>--Select--</asp:ListItem>                                                                                                
<asp:ListItem>Expired</asp:ListItem>                                                                                                
<asp:ListItem>Lost/Stolen</asp:ListItem>                                                                                                
<asp:ListItem>Location Change</asp:ListItem>                                                                                            
</asp:DropDownList>

However adding the InitialValue like this worked instantly for a compare Validator.

<asp:ListItem Text="-- Select --" Value="-1"></asp:ListItem>

Excel VBA Check if directory exists error

Use the FolderExists method of the Scripting object.

Public Function dirExists(s_directory As String) As Boolean
    Dim oFSO As Object
    Set oFSO = CreateObject("Scripting.FileSystemObject")
    dirExists = oFSO.FolderExists(s_directory)
End Function

The database cannot be opened because it is version 782. This server supports version 706 and earlier. A downgrade path is not supported

Try changing Tools > Options > Database Tools > Data Connections > SQL Server Instance Name.

The default for VS2013 is (LocalDB)\v11.0.

Changing to (LocalDB)\MSSQLLocalDB, for example, seems to work - no more version 782 error.

How to display the value of the bar on each bar with pyplot.barh()?

Add:

for i, v in enumerate(y):
    ax.text(v + 3, i + .25, str(v), color='blue', fontweight='bold')

result:

enter image description here

The y-values v are both the x-location and the string values for ax.text, and conveniently the barplot has a metric of 1 for each bar, so the enumeration i is the y-location.

How to check if a file exists in Ansible?

You can use Ansible stat module to register the file, and when module to apply the condition.

- name: Register file
      stat:
        path: "/tmp/test_file"
      register: file_path

- name: Create file if it doesn't exists
      file: 
        path: "/tmp/test_file"
        state: touch
      when: file_path.stat.exists == False

How to push both key and value into an Array in Jquery

There are no keys in JavaScript arrays. Use objects for that purpose.

var obj = {};

$.getJSON("displayjson.php",function (data) {
    $.each(data.news, function (i, news) {
        obj[news.title] = news.link;
    });                      
});

// later:
$.each(obj, function (index, value) {
    alert( index + ' : ' + value );
});

In JavaScript, objects fulfill the role of associative arrays. Be aware that objects do not have a defined "sort order" when iterating them (see below).

However, In your case it is not really clear to me why you transfer data from the original object (data.news) at all. Why do you not simply pass a reference to that object around?


You can combine objects and arrays to achieve predictable iteration and key/value behavior:

var arr = [];

$.getJSON("displayjson.php",function (data) {
    $.each(data.news, function (i, news) {
        arr.push({
            title: news.title, 
            link:  news.link
        });
    });                      
});

// later:
$.each(arr, function (index, value) {
    alert( value.title + ' : ' + value.link );
});

Twitter Bootstrap button click to toggle expand/collapse text section above button

I wanted an "expand/collapse" container with a plus and minus button to open and close it. This uses the standard bootstrap event and has animation. This is BS3.

enter image description here

HTML:

<button id="button" type="button" class="btn btn-primary" 
  data-toggle="collapse" data-target="#demo">
  <span class="glyphicon glyphicon-collapse-down"></span> Show
</button>

<div id="demo" class="collapse">
  <ol class="list-group">
      <li class="list-group-item">Warrior</li>
      <li class="list-group-item">Adventurer</li>
      <li class="list-group-item">Mage</li>
  </ol>
</div>

JS:

$(function(){
  $('#demo').on('hide.bs.collapse', function () {
    $('#button').html('<span class="glyphicon glyphicon-collapse-down"></span> Show');
  })
  $('#demo').on('show.bs.collapse', function () {
    $('#button').html('<span class="glyphicon glyphicon-collapse-up"></span> Hide');
  })
})

Example:

http://plnkr.co/edit/aG5BtH?p=preview

How to read integer values from text file

How large are the values? Java 6 has Scanner class that can read anything from int (32 bit), long (64-bit) to BigInteger (arbitrary big integer).

For Java 5 or 4, Scanner is there, but no support for BigInteger. You have to read line by line (with readLine of Scanner class) and create BigInteger object from the String.

Python: pandas merge multiple dataframes

@dannyeuu's answer is correct. pd.concat naturally does a join on index columns, if you set the axis option to 1. The default is an outer join, but you can specify inner join too. Here is an example:

x = pd.DataFrame({'a': [2,4,3,4,5,2,3,4,2,5], 'b':[2,3,4,1,6,6,5,2,4,2], 'val': [1,4,4,3,6,4,3,6,5,7], 'val2': [2,4,1,6,4,2,8,6,3,9]})
x.set_index(['a','b'], inplace=True)
x.sort_index(inplace=True)

y = x.__deepcopy__()
y.loc[(14,14),:] = [3,1]
y['other']=range(0,11)

y.sort_values('val', inplace=True)

z = x.__deepcopy__()
z.loc[(15,15),:] = [3,4]
z['another']=range(0,22,2)
z.sort_values('val2',inplace=True)


pd.concat([x,y,z],axis=1)

c# razor url parameter from view

@(ViewContext.RouteData.Values["parameterName"])

worked with ROUTE PARAM.

Request.Params["paramName"]

did not work with ROUTE PARAM.

Get height and width of a layout programmatically

I had same issue but didn't want to draw on screen before measuring so I used this method of measuring the view before trying to get the height and width.

Example of use:

layoutView(view);
int height = view.getHeight();

//...

void layoutView(View view) {
    view.setDrawingCacheEnabled(true);
    int wrapContentSpec = 
        MeasureSpec.makeMeasureSpec(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
    view.measure(wrapContentSpec, wrapContentSpec);
    view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
}

C# code to validate email address

There is culture problem in regex in C# rather then js. So we need to use regex in US mode for email check. If you don't use ECMAScript mode, your language special characters are imply in A-Z with regex.

Regex.IsMatch(email, @"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9_\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$", RegexOptions.ECMAScript)

A fatal error has been detected by the Java Runtime Environment: SIGSEGV, libjvm

Generally if something works on various computers but fails on only one computer, then there's something wrong with that computer. Here are a few things to check:
(1) Are you running the same stuff on that computer -- OS including patches, etc.
(2) Does the computer report problems? Where to look depends on the OS, but it looks like you're using linux, so check syslog
(3) Run hardware diagnostics, e.g. the ones recommended here. Start with memory and disk checks in particular.

If you can't turn up any issues, then search for a similar issue in the bug parade for whichever VM you're using. Unfortunately if you're already on the latest version of the VM, then you won't necessarily find a fix.

Finally, one more option is simply to try another VM -- e.g. OpenJDK or JRockit, instead of Oracle's standard.

proper name for python * operator?

The Python Tutorial simply calls it 'the *-operator'. It performs unpacking of arbitrary argument lists.

Print a string as hex bytes?

This can be done in following ways:

from __future__ import print_function
str = "Hello World !!"
for char in str:
    mm = int(char.encode('hex'), 16)
    print(hex(mm), sep=':', end=' ' )

The output of this will be in hex as follows:

0x48 0x65 0x6c 0x6c 0x6f 0x20 0x57 0x6f 0x72 0x6c 0x64 0x20 0x21 0x21

ASP.NET: HTTP Error 500.19 – Internal Server Error 0x8007000d

When trying to set up a .NET Core 1.0 website I got this error, and tried everything else I could find with no luck, including checking the web.config file, IIS_IUSRS permissions, IIS URL rewrite module, etc. In the end, I installed DotNetCore.1.0.0-WindowsHosting.exe from this page: https://www.microsoft.com/net/download and it started working right away.

Specific link to download: https://go.microsoft.com/fwlink/?LinkId=817246

How to add LocalDB to Visual Studio 2015 Community's SQL Server Object Explorer?

  1. Search for sqllocaldb or localDB in your windows start menu and right click on open file location
  2. Open command prompt in the file location you found from the search
  3. On your command prompt type sqllocaldb start

  4. Use <add name="defaultconnection" connectionString="Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=tododb;Integrated Security=True" providerName="System.Data.SqlClient" />

Reading a binary file with python

I too found Python lacking when it comes to reading and writing binary files, so I wrote a small module (for Python 3.6+).

With binaryfile you'd do something like this (I'm guessing, since I don't know Fortran):

import binaryfile

def particle_file(f):
    f.array('group_ids')  # Declare group_ids to be an array (so we can use it in a loop)
    f.skip(4)  # Bytes 1-4
    num_particles = f.count('num_particles', 'group_ids', 4)  # Bytes 5-8
    f.int('num_groups', 4)  # Bytes 9-12
    f.skip(8)  # Bytes 13-20
    for i in range(num_particles):
        f.struct('group_ids', '>f')  # 4 bytes x num_particles
    f.skip(4)

with open('myfile.bin', 'rb') as fh:
    result = binaryfile.read(fh, particle_file)
print(result)

Which produces an output like this:

{
    'group_ids': [(1.0,), (0.0,), (2.0,), (0.0,), (1.0,)],
    '__skipped': [b'\x00\x00\x00\x08', b'\x00\x00\x00\x08\x00\x00\x00\x14', b'\x00\x00\x00\x14'],
    'num_particles': 5,
    'num_groups': 3
}

I used skip() to skip the additional data Fortran adds, but you may want to add a utility to handle Fortran records properly instead. If you do, a pull request would be welcome.

How do I encode URI parameter values?

Mmhh I know you've already discarded URLEncoder, but despite of what the docs say, I decided to give it a try.

You said:

For example, given an input:

http://google.com/resource?key=value

I expect the output:

http%3a%2f%2fgoogle.com%2fresource%3fkey%3dvalue

So:

C:\oreyes\samples\java\URL>type URLEncodeSample.java
import java.net.*;

public class URLEncodeSample {
    public static void main( String [] args ) throws Throwable {
        System.out.println( URLEncoder.encode( args[0], "UTF-8" ));
    }
}

C:\oreyes\samples\java\URL>javac URLEncodeSample.java

C:\oreyes\samples\java\URL>java URLEncodeSample "http://google.com/resource?key=value"
http%3A%2F%2Fgoogle.com%2Fresource%3Fkey%3Dvalue

As expected.

What would be the problem with this?

jQuery: Check if special characters exists in string

var specialChars = "<>@!#$%^&*()_+[]{}?:;|'\"\\,./~`-="
var check = function(string){
    for(i = 0; i < specialChars.length;i++){
        if(string.indexOf(specialChars[i]) > -1){
            return true
        }
    }
    return false;
}

if(check($('#Search').val()) == false){
    // Code that needs to execute when none of the above is in the string
}else{
    alert('Your search string contains illegal characters.');
}

How to run .APK file on emulator

Steps (These apply for Linux. For other OS, visit here) -

  1. Copy the apk file to platform-tools in android-sdk linux folder.
  2. Open Terminal and navigate to platform-tools folder in android-sdk.
  3. Then Execute this command -

    ./adb install FileName.apk

  4. If the operation is successful (the result is displayed on the screen), then you will find your file in the launcher of your emulator.

For more info can check this link : android videos

How can I add the new "Floating Action Button" between two widgets/layouts

Best practice:

  • Add compile 'com.android.support:design:25.0.1' to gradle file
  • Use CoordinatorLayout as root view.
  • Add layout_anchorto the FAB and set it to the top view
  • Add layout_anchorGravity to the FAB and set it to: bottom|right|end

enter image description here

<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <LinearLayout
            android:id="@+id/viewA"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="0.6"
            android:background="@android:color/holo_purple"
            android:orientation="horizontal"/>

        <LinearLayout
            android:id="@+id/viewB"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="0.4"
            android:background="@android:color/holo_orange_light"
            android:orientation="horizontal"/>

    </LinearLayout>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:clickable="true"
        android:src="@drawable/ic_done"
        app:layout_anchor="@id/viewA"
        app:layout_anchorGravity="bottom|right|end"/>

</android.support.design.widget.CoordinatorLayout>

How do I create an array of strings in C?

Here are some of your options:

char a1[][14] = { "blah", "hmm" };
char* a2[] = { "blah", "hmm" };
char (*a3[])[] = { &"blah", &"hmm" };  // only since you brought up the syntax -

printf(a1[0]); // prints blah
printf(a2[0]); // prints blah
printf(*a3[0]); // prints blah

The advantage of a2 is that you can then do the following with string literals

a2[0] = "hmm";
a2[1] = "blah";

And for a3 you may do the following:

a3[0] = &"hmm";
a3[1] = &"blah";

For a1 you will have to use strcpy() (better yet strncpy()) even when assigning string literals. The reason is that a2, and a3 are arrays of pointers and you can make their elements (i.e. pointers) point to any storage, whereas a1 is an array of 'array of chars' and so each element is an array that "owns" its own storage (which means it gets destroyed when it goes out of scope) - you can only copy stuff into its storage.

This also brings us to the disadvantage of using a2 and a3 - since they point to static storage (where string literals are stored) the contents of which cannot be reliably changed (viz. undefined behavior), if you want to assign non-string literals to the elements of a2 or a3 - you will first have to dynamically allocate enough memory and then have their elements point to this memory, and then copy the characters into it - and then you have to be sure to deallocate the memory when done.

Bah - I miss C++ already ;)

p.s. Let me know if you need examples.

iptables v1.4.14: can't initialize iptables table `nat': Table does not exist (do you need to insmod?)

On OpenSUSE 15.3 systemd log reported this error (insmod suggestion was unhelpful).

Feb 18 08:36:38 vagrant-openSUSE-Leap dockerd[20635]: iptables v1.6.2: can't initialize iptables table `nat': Table does not exist (do you need to insmod?)

REBOOT fixed the problem

How to set the matplotlib figure default size in ipython notebook?

Just for completeness, this also works

from IPython.core.pylabtools import figsize
figsize(14, 7)

It is a wrapper aroung the rcParams solution

prevent property from being serialized in web API

Instead of letting everything get serialized by default, you can take the "opt-in" approach. In this scenario, only the properties you specify are allowed to be serialized. You do this with the DataContractAttribute and DataMemberAttribute, found in the System.Runtime.Serialization namespace.

The DataContactAttribute is applied to the class, and the DataMemberAttribute is applied to each member you want to be serialized:

[DataContract]
public class MyClass {

  [DataMember]
  public int Id { get; set;} // Serialized

  [DataMember]
  public string Name { get; set; } // Serialized

  public string DontExposeMe { get; set; } // Will not be serialized
}

Dare I say this is a better approach because it forces you to make explicit decisions about what will or will not make it through serialization. It also allows your model classes to live in a project by themselves, without taking a dependency on JSON.net just because somewhere else you happen to be serializing them with JSON.net.

What is the difference between '/' and '//' when used for division?

The answer of the equation is rounded to the next smaller integer or float with .0 as decimal point.

>>>print 5//2
2
>>> print 5.0//2
2.0
>>>print 5//2.0
2.0
>>>print 5.0//2.0
2.0

How do I revert all local changes in Git managed project to previous state?

This question is more about broader repository reset / revert, but in case if you're interested in reverting individual change - I've added similar answer in here:

https://stackoverflow.com/a/60890371/2338477

Answers to questions:

  • How to revert individual change with or without change preserving in git history

  • How to return back to old version to restart from same state

Why doesn't Console.Writeline, Console.Write work in Visual Studio Express?

The output window isn't the console. Try the methods in System.Diagnostics.Debug

When to use RDLC over RDL reports?

if you want to use report in asp.net then use .rdl if you want to use /view in report builder / report server then use .rdlc just by converting format manually it works

Is there a minlength validation attribute in HTML5?

The minLength attribute (unlike maxLength) does not exist natively in HTML5. However, there a some ways to validate a field if it contains less than x characters.

An example is given using jQuery at this link: http://docs.jquery.com/Plugins/Validation/Methods/minlength

<html>
    <head>
        <script src="http://code.jquery.com/jquery-latest.js"></script>
        <script type="text/javascript" src="http://jzaefferer.github.com/jquery-validation/jquery.validate.js"></script>
        <script type="text/javascript">
            jQuery.validator.setDefaults({
                debug: true,
                success: "valid"
            });;
        </script>

        <script>
            $(document).ready(function(){
                $("#myform").validate({
                    rules: {
                        field: {
                            required: true,
                            minlength: 3
                        }
                    }
                });
            });
        </script>
    </head>

    <body>
        <form id="myform">
            <label for="field">Required, Minimum length 3: </label>
            <input class="left" id="field" name="field" />
            <br/>
            <input type="submit" value="Validate!" />
        </form>
    </body>

</html>

Converting a UNIX Timestamp to Formatted Date String

$unixtime_to_date = date('jS F Y h:i:s A (T)', $unixtime);

This should work to.

How to pass complex object to ASP.NET WebApi GET from jQuery ajax call?

After finding this StackOverflow question/answer

Complex type is getting null in a ApiController parameter

the [FromBody] attribute on the controller method needs to be [FromUri] since a GET does not have a body. After this change the "filter" complex object is passed correctly.

How to retrieve a module's path?

import module
print module.__path__

Packages support one more special attribute, __path__. This is initialized to be a list containing the name of the directory holding the package’s __init__.py before the code in that file is executed. This variable can be modified; doing so affects future searches for modules and subpackages contained in the package.

While this feature is not often needed, it can be used to extend the set of modules found in a package.

Source

Read lines from a file into a Bash array

The readarray command (also spelled mapfile) was introduced in bash 4.0.

readarray -t a < /path/to/filename

C# How to determine if a number is a multiple of another?

there are some syntax errors to your program heres a working code;

#include<stdio.h>
int main()
{
int a,b;
printf("enter any two number\n");
scanf("%d%d",&a,&b);
if (a%b==0){
printf("this is  multiple number");
}
else if (b%a==0){
printf("this is multiple number");
}
else{
printf("this is not multiple number");
return 0;
}

}

ORA-00918: column ambiguously defined in SELECT *

You can also see this error when selecting for a union where corresponding columns can be null.

select * from (select D.dept_no, D.nullable_comment
                  from dept D
       union
               select R.dept_no, NULL
                 from redundant_dept R
)

This apparently confuses the parser, a solution is to assign a column alias to the always null column.

select * from (select D.dept_no, D.comment
                  from dept D
       union
               select R.dept_no, NULL "nullable_comment"
                 from redundant_dept R
)

The alias does not have to be the same as the corresponding column, but the column heading in the result is driven by the first query from among the union members, so it's probably a good practice.

Bitwise and in place of modulus operator

Modulo "7" without "%" operator

int a = x % 7;

int a = (x + x / 7) & 7;

Run php function on button click

I tried the code of William, Thanks brother.

but it's not working as a simple button I have to add form with method="post". Also I have to write submit instead of button.

here is my code below..

<form method="post">
    <input type="submit" name="test" id="test" value="RUN" /><br/>
</form>

<?php

function testfun()
{
   echo "Your test function on button click is working";
}

if(array_key_exists('test',$_POST)){
   testfun();
}

?>

Finding the max value of an attribute in an array of objects

Or a simple sort! Keeping it real :)

array.sort((a,b)=>a.y<b.y)[0].y

How to filter in NaN (pandas)?

Pandas uses numpy's NaN value. Use numpy.isnan to obtain a Boolean vector from a pandas series.

Replacing NULL and empty string within Select statement

An alternative way can be this: - recommended as using just one expression -

case when address.country <> '' then address.country
else 'United States'
end as country

Note: Result of checking null by <> operator will return false.
And as documented: NULLIF is equivalent to a searched CASE expression
and COALESCE expression is a syntactic shortcut for the CASE expression.
So, combination of those are using two time of case expression.

Java Compare Two List's object values?

This can be done easily through Java8 using forEach and removeIf method.

Take two lists. Iterate from listA and compare elements inside listB

Write any condition inside removeIf method.

Hope this will help

listToCompareFrom.forEach(entity -> listToRemoveFrom.removeIf(x -> x.contains(entity)));

How to check if JSON return is empty with jquery

$.getJSON(url,function(json){
if ( json.length == 0 ) 
{
console.log("NO !")
}
});

How can I give an imageview click effect like a button on Android?

It's possible to do with just one image file using the ColorFilter method. However, ColorFilter expects to work with ImageViews and not Buttons, so you have to transform your buttons into ImageViews. This isn't a problem if you're using images as your buttons anyway, but it's more annoying if you had text... Anyway, assuming you find a way around the problem with text, here's the code to use:

ImageView button = (ImageView) findViewById(R.id.button);
button.setColorFilter(0xFFFF0000, PorterDuff.Mode.MULTIPLY);

That applies a red overlay to the button (the color code is the hex code for fully opaque red - first two digits are transparency, then it's RR GG BB.).

Installing SetupTools on 64-bit Windows

Get the file register.py from this gist. Save it on your C drive or D drive, go to CMD to run it with:

'python register.py'

Then you will be able to install it.

Typedef function pointer?

#include <stdio.h>
#include <math.h>

/*
To define a new type name with typedef, follow these steps:
1. Write the statement as if a variable of the desired type were being declared.
2. Where the name of the declared variable would normally appear, substitute the new type name.
3. In front of everything, place the keyword typedef.
*/

// typedef a primitive data type
typedef double distance;

// typedef struct 
typedef struct{
    int x;
    int y;
} point;

//typedef an array 
typedef point points[100]; 

points ps = {0}; // ps is an array of 100 point 

// typedef a function
typedef distance (*distanceFun_p)(point,point) ; // TYPE_DEF distanceFun_p TO BE int (*distanceFun_p)(point,point)

// prototype a function     
distance findDistance(point, point);

int main(int argc, char const *argv[])
{
    // delcare a function pointer 
    distanceFun_p func_p;

    // initialize the function pointer with a function address
    func_p = findDistance;

    // initialize two point variables 
    point p1 = {0,0} , p2 = {1,1};

    // call the function through the pointer
    distance d = func_p(p1,p2);

    printf("the distance is %f\n", d );

    return 0;
}

distance findDistance(point p1, point p2)
{
distance xdiff =  p1.x - p2.x;
distance ydiff =  p1.y - p2.y;

return sqrt( (xdiff * xdiff) + (ydiff * ydiff) );
}

Installing PG gem on OS X - failure to build native extension

I tried everything for hours but the following finally fixed it (I'm on OS X 10.9.4):

  1. Install Xcode command line tools (Apple Developer site)
  2. brew uninstall postgresql
  3. brew install postgresql
  4. ARCHFLAGS="-arch x86_64" gem install pg

VBScript to send email without running Outlook

Yes. Blat or any other self contained SMTP mailer. Blat is a fairly full featured SMTP client that runs from command line

Blat is here

How to create a shortcut using PowerShell

Beginning PowerShell 5.0 New-Item, Remove-Item, and Get-ChildItem have been enhanced to support creating and managing symbolic links. The ItemType parameter for New-Item accepts a new value, SymbolicLink. Now you can create symbolic links in a single line by running the New-Item cmdlet.

New-Item -ItemType SymbolicLink -Path "C:\temp" -Name "calc.lnk" -Value "c:\windows\system32\calc.exe"

Be Carefull a SymbolicLink is different from a Shortcut, shortcuts are just a file. They have a size (A small one, that just references where they point) and they require an application to support that filetype in order to be used. A symbolic link is filesystem level, and everything sees it as the original file. An application needs no special support to use a symbolic link.

Anyway if you want to create a Run As Administrator shortcut using Powershell you can use

$file="c:\temp\calc.lnk"
$bytes = [System.IO.File]::ReadAllBytes($file)
$bytes[0x15] = $bytes[0x15] -bor 0x20 #set byte 21 (0x15) bit 6 (0x20) ON (Use –bor to set RunAsAdministrator option and –bxor to unset)
[System.IO.File]::WriteAllBytes($file, $bytes)

If anybody want to change something else in a .LNK file you can refer to official Microsoft documentation.

C# HttpClient 4.5 multipart/form-data upload

public async Task<object> PassImageWithText(IFormFile files)
{
    byte[] data;
    string result = "";
    ByteArrayContent bytes;

    MultipartFormDataContent multiForm = new MultipartFormDataContent();

    try
    {
        using (var client = new HttpClient())
        {
            using (var br = new BinaryReader(files.OpenReadStream()))
            {
                data = br.ReadBytes((int)files.OpenReadStream().Length);
            }

            bytes = new ByteArrayContent(data);
            multiForm.Add(bytes, "files", files.FileName);
            multiForm.Add(new StringContent("value1"), "key1");
            multiForm.Add(new StringContent("value2"), "key2");

            var res = await client.PostAsync(_MEDIA_ADD_IMG_URL, multiForm);
        }
    }
    catch (Exception e)
    {
        throw new Exception(e.ToString());
    }

    return result;
}

JQuery find first parent element with specific class prefix

Use .closest() with a selector:

var $div = $('#divid').closest('div[class^="div-a"]');

How to create relationships in MySQL

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

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

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

Best way to update data with a RecyclerView adapter

RecyclerView's Adapter doesn't come with many methods otherwise available in ListView's adapter. But your swap can be implemented quite simply as:

class MyRecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
   List<Data> data;
   ...

    public void swap(ArrayList<Data> datas)
    {
        data.clear();
        data.addAll(datas);
        notifyDataSetChanged();     
    }
}

Also there is a difference between

list.clear();
list.add(data);

and

list = newList;

The first is reusing the same list object. The other is dereferencing and referencing the list. The old list object which can no longer be reached will be garbage collected but not without first piling up heap memory. This would be the same as initializing new adapter everytime you want to swap data.

How to remove elements from a generic list while iterating over it?

The cost of removing an item from the list is proportional to the number of items following the one to be removed. In the case where the first half of the items qualify for removal, any approach which is based upon removing items individually will end up having to perform about N*N/4 item-copy operations, which can get very expensive if the list is large.

A faster approach is to scan through the list to find the first item to be removed (if any), and then from that point forward copy each item which should be retained to the spot where it belongs. Once this is done, if R items should be retained, the first R items in the list will be those R items, and all of the items requiring deletion will be at the end. If those items are deleted in reverse order, the system won't end up having to copy any of them, so if the list had N items of which R items, including all of the first F, were retained, it will be necessary to copy R-F items, and shrink the list by one item N-R times. All linear time.

from jquery $.ajax to angular $http

you can use $.param to assign data :

 $http({
  url: "http://example.appspot.com/rest/app",
  method: "POST",
  data: $.param({"foo":"bar"})
  }).success(function(data, status, headers, config) {
   $scope.data = data;
  }).error(function(data, status, headers, config) {
   $scope.status = status;
 });

look at this : AngularJS + ASP.NET Web API Cross-Domain Issue

Kafka consumer list

I do not see it mentioned here, but a command that i use often and that helps me to have a bird's eye view on all groups, topics, partitions, offsets, lags, consumers, etc

kafka-consumer-groups.bat --bootstrap-server localhost:9092 --describe --all-groups

A sample would look like this:

GROUP TOPIC PARTITION  CURRENT-OFFSET  LOG-END-OFFSET  LAG CONSUMER-ID HOST CLIENT-ID
Group Topic 2          7               7               0   <SOME-ID>   XXXX <SOME-ID>
:
:

The most important column is the LAG, where for a healthy platform, ideally it should be 0(or nearer to 0 or a low number for high throughput) - at all times. So make sure you monitor it!!! ;-).

P.S:
An interesting article on how you can monitor the lag can be found here.

jQuery .live() vs .on() method for adding a click event after loading dynamic html

If you want the click handler to work for an element that gets loaded dynamically, then you set the event handler on a parent object (that does not get loaded dynamically) and give it a selector that matches your dynamic object like this:

$('#parent').on("click", "#child", function() {});

The event handler will be attached to the #parent object and anytime a click event bubbles up to it that originated on #child, it will fire your click handler. This is called delegated event handling (the event handling is delegated to a parent object).

It's done this way because you can attach the event to the #parent object even when the #child object does not exist yet, but when it later exists and gets clicked on, the click event will bubble up to the #parent object, it will see that it originated on #child and there is an event handler for a click on #child and fire your event.

How to properly exit a C# application?

I would either one of the following:

Application.Exit();

for a winform or

Environment.Exit(0);

for a console application (works on winforms too).

Thanks!

How to sort a list of strings?

The proper way to sort strings is:

import locale
locale.setlocale(locale.LC_ALL, 'en_US.UTF-8') # vary depending on your lang/locale
assert sorted((u'Ab', u'ad', u'aa'), cmp=locale.strcoll) == [u'aa', u'Ab', u'ad']

# Without using locale.strcoll you get:
assert sorted((u'Ab', u'ad', u'aa')) == [u'Ab', u'aa', u'ad']

The previous example of mylist.sort(key=lambda x: x.lower()) will work fine for ASCII-only contexts.

Returning Month Name in SQL Server Query

SELECT MONTHNAME( `col1` ) FROM `table_name` 

Execute JavaScript code stored as a string

If you want to execute a specific command (that is string) after a specific time - cmd=your code - InterVal=delay to run

 function ExecStr(cmd, InterVal) {
    try {
        setTimeout(function () {
            var F = new Function(cmd);
            return (F());
        }, InterVal);
    } catch (e) { }
}
//sample
ExecStr("alert(20)",500);

How to build jars from IntelliJ properly?

In case you are reading this answer because you are facing "resource file not found" error, try this:

  1. File -> Project Structure -> Artiface -> New, type is Other.
  2. Give it a nice name, and in the Output Layout, press Create Archive to create a new jar, and again, give it a nice name ;)
  3. Click on the jar you just added, add your compiled module output in the jar.
  4. Click on the jar again, in the lower pane, select your project path and add Manifest File then set correct Main Class and Class Path.
  5. Click Add Library Files, and select libraries you need (you can use Ctrl+A to select all).
  6. Build -> Build Artifact -> Clean & Build and see if the error is gone.

File size exceeds configured limit (2560000), code insight features not available

In IntelliJ 2016 and newer you can change this setting from the Help menu, Edit Custom Properties (as commented by @eggplantbr).

On older versions, there's no GUI to do it. But you can change it if you edit the IntelliJ IDEA Platform Properties file:

#---------------------------------------------------------------------
# Maximum file size (kilobytes) IDE should provide code assistance for.
# The larger file is the slower its editor works and higher overall system memory requirements are
# if code assistance is enabled. Remove this property or set to very large number if you need
# code assistance for any files available regardless their size.
#---------------------------------------------------------------------
idea.max.intellisense.filesize=2500

How do I fix a "Performance counter registry hive consistency" when installing SQL Server R2 Express?

Use Rafael's solution: http://social.msdn.microsoft.com/Forums/en/sqlsetupandupgrade/thread/dddf0349-557b-48c7-bf82-6bd1adb5c694..

Added data from link to avoid link rot..

put this at any Console application:

string.Format("{0,3}", CultureInfo.InstalledUICulture.Parent.LCID.ToString("X")).Replace(" ", "0");

Watch the result. At mine it was "016".

Then you go to the registry at this key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib

and create another one with the name you got from the string.Format result.

In my case:

"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib\016"

and copy the info that is on any other key in this Perflib to this key you just created. Run the instalation again.

Just run the script and get your 3 digit code. Then follow his simple and quick steps, and you're ready to go!

Cheers

Margin while printing html page

If you know the target paper size, you can place your content in a DIV with that specific size and add a margin to that DIV to simulate the print margin. Unfortunately, I don't believe you have extra control over the print functionality apart from just show the print dialog box.

Sql Server trigger insert values from new row into another table

You can use OLDand NEW in the trigger to access those values which had changed in that trigger. Mysql Ref

Executing a batch file in a remote machine through PsExec

Here's my current solution to run any code remotely on a given machine or list of machines asynchronously with logging, too!

@echo off
:: by Ralph Buchfelder, thanks to Mark Russinovich and Rob van der Woude for their work!
:: requires PsExec.exe to be in the same directory (download from http://technet.microsoft.com/de-de/sysinternals/bb897553.aspx)
:: troubleshoot remote commands with PsExec arguments -i or -s if neccessary (see http://forum.sysinternals.com/pstools_forum8.html)
:: will run *in parallel* on a list of remote pcs (if given); to run serially please remove 'START "" CMD.EXE /C' from the psexec call


:: help
if '%1' =='-h' (
 echo.
 echo %~n0
 echo.
 echo Runs a command on one or many remote machines. If no input parameters
 echo are given you will be asked for a target remote machine.
 echo.
 echo You will be prompted for remote credentials with elevated privileges.
 echo.
 echo UNC paths and local paths can be supplied.
 echo Commands will be executed on the remote side just the way you typed
 echo them, so be sure to mind extensions and the path variable!
 echo.
 echo Please note that PsExec.exe must be allowed on remote machines, i.e.
 echo not blocked by firewall or antivirus solutions.
 echo.
 echo Syntax: %~n0 [^<inputfile^>]
 echo.
 echo     inputfile      = a plain text file ^(one hostname or ip address per line^)
 echo.
 echo.
 echo Example:
 echo %~n0 mylist.txt
 exit /b 0
)


:checkAdmin
>nul 2>&1 "%SYSTEMROOT%\system32\cacls.exe" "%SYSTEMROOT%\system32\config\system"
if '%errorlevel%' neq '0' (
 echo Set UAC = CreateObject^("Shell.Application"^) > "%temp%\getadmin.vbs"
 echo UAC.ShellExecute "%~s0", "", "", "runas", 1 >> "%temp%\getadmin.vbs"
 "%temp%\getadmin.vbs"
 del "%temp%\getadmin.vbs"
 exit /B
)
set ADMINTESTDIR=%WINDIR%\System32\Test_%RANDOM%
mkdir "%ADMINTESTDIR%" 2>NUL
if errorlevel 1 (
 cls
 echo ERROR: This script requires elevated privileges!
 echo.
 echo Launch by Right-Click / Run as Administrator ...
 pause
 exit /b 1
) else (
 rd /s /q "%ADMINTESTDIR%"
 echo Running with elevated privileges...
)
echo.


:checkRequirements
if not exist "%~dp0PsExec.exe" (
 echo PsExec.exe from Sysinternals/Microsoft not found 
 echo in %~dp0
 echo.
 echo Download from http://technet.microsoft.com/de-de/sysinternals/bb897553.aspx
 echo.
 pause
 exit /B
)


:environment
setlocal
echo.
echo %~n0
echo _____________________________
echo.
echo Working directory:  %cd%\
echo Script directory:   %~dp0
echo.
SET /P REMOTE_USER=Domain\Administrator : 
SET "psCommand=powershell -Command "$pword = read-host 'Kennwort' -AsSecureString ; ^
    $BSTR=[System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($pword); ^
        [System.Runtime.InteropServices.Marshal]::PtrToStringAuto($BSTR)""
for /f "usebackq delims=" %%p in (`%psCommand%`) do set REMOTE_PASS=%%p
if NOT DEFINED REMOTE_PASS SET /P REMOTE_PASS=Password             : 
echo.
if '%1' =='' goto menu
SET REMOTE_LIST=%1


:inputMultipleTargets
if not exist %REMOTE_LIST% (
 echo File %REMOTE_LIST% not found
 goto menu
)
type %REMOTE_LIST% >nul
if '%errorlevel%' neq '0' (
 echo Access denied %REMOTE_LIST%
 goto menu
)
set batchProcessing=true
echo Batch processing:   %REMOTE_LIST%   ...
ping -n 2 127.0.0.1 >nul
goto runOnce


:menu
if exist "%~dp0last.computer"  set /p LAST_COMPUTER=<"%~dp0last.computer"
if exist "%~dp0last.listing"   set /p LAST_LISTING=<"%~dp0last.listing"
if exist "%~dp0last.directory" set /p LAST_DIRECTORY=<"%~dp0last.directory"
if exist "%~dp0last.command"   set /p LAST_COMMAND=<"%~dp0last.command"
if exist "%~dp0last.timestamp" set /p LAST_TIMESTAMP=<"%~dp0last.timestamp"
echo.
echo.
echo                (1)  select target computer [default]
echo                (2)  select multiple computers
echo                     -----------------------------------
echo                     last target : %LAST_COMPUTER%
echo                     last listing: %LAST_LISTING%
echo                     last path   : %LAST_DIRECTORY%
echo                     last command: %LAST_COMMAND%
echo                     last run    : %LAST_TIMESTAMP%
echo                     -----------------------------------
echo                (0)  exit
echo.
echo ENTER your choice.
echo.
echo.
:mychoice
SET /P mychoice=(0, 1, ...): 
if NOT DEFINED mychoice  goto promptSingleTarget
if "%mychoice%"=="1"     goto promptSingleTarget
if "%mychoice%"=="2"     goto promptMultipleTargets
if "%mychoice%"=="0"     goto end
goto mychoice


:promptMultipleTargets
echo.
echo Please provide an input file
echo [one IP address or hostname per line]
SET /P REMOTE_LIST=Filename             : 
goto inputMultipleTargets


:promptSingleTarget
SET batchProcessing=
echo.
echo Please provide a hostname
SET /P REMOTE_COMPUTER=Target computer      : 
goto runOnce


:runOnce
cls
echo Note: Paths are mandatory for CMD-commands (e.g. dir,copy) to work!
echo       Paths are provided on the remote machine via PUSHD.
echo.
SET /P REMOTE_PATH=UNC-Path or folder : 
SET /P REMOTE_CMD=Command with params: 
SET REMOTE_TIMESTAMP=%DATE% %TIME:~0,8%
echo.
echo Remote command starting (%REMOTE_PATH%\%REMOTE_CMD%) on %REMOTE_TIMESTAMP%...
if not defined batchProcessing goto runOnceSingle


:runOnceMulti
REM do for each line; this circumvents PsExec's @file to have stdouts separately
SET REMOTE_LOG=%~dp0\log\%REMOTE_LIST%
if not exist %REMOTE_LOG% md %REMOTE_LOG%
for /F "tokens=*" %%A in (%REMOTE_LIST%) do (
 if "%REMOTE_PATH%" =="" START "" CMD.EXE /C ^(%~dp0PSEXEC -u %REMOTE_USER% -p %REMOTE_PASS% -h -accepteula \\%%A cmd /c "%REMOTE_CMD%" ^>"%REMOTE_LOG%\%%A.log" 2^>"%REMOTE_LOG%\%%A_debug.log" ^)
 if not "%REMOTE_PATH%" =="" START "" CMD.EXE /C ^(%~dp0PSEXEC -u %REMOTE_USER% -p %REMOTE_PASS% -h -accepteula \\%%A cmd /c "pushd %REMOTE_PATH% && %REMOTE_CMD% & popd" ^>"%REMOTE_LOG%\%%A.log" 2^>"%REMOTE_LOG%\%%A_debug.log" ^)
)
goto restart


:runOnceSingle
SET REMOTE_LOG=%~dp0\log
if not exist %REMOTE_LOG% md %REMOTE_LOG%
if "%REMOTE_PATH%" =="" %~dp0PSEXEC -u %REMOTE_USER% -p %REMOTE_PASS% -h -accepteula \\%REMOTE_COMPUTER% cmd /c "%REMOTE_CMD%" >"%REMOTE_LOG%\%REMOTE_COMPUTER%.log" 2>"%REMOTE_LOG%\%REMOTE_COMPUTER%_debug.log"
if not "%REMOTE_PATH%" =="" %~dp0PSEXEC -u %REMOTE_USER% -p %REMOTE_PASS% -h -accepteula \\%REMOTE_COMPUTER% cmd /c "pushd %REMOTE_PATH% && %REMOTE_CMD% & popd" >"%REMOTE_LOG%\%REMOTE_COMPUTER%.log" 2>"%REMOTE_LOG%\%REMOTE_COMPUTER%_debug.log"
goto restart


:restart
echo.
echo.
echo Batch completed. Finished with last errorlevel %errorlevel% .
echo All outputs have been saved to %~dp0log\%REMOTE_TIMESTAMP%\.
echo %REMOTE_PATH% >"%~dp0last.directory"
echo %REMOTE_CMD% >"%~dp0last.command"
echo %REMOTE_LIST% >"%~dp0last.listing"
echo %REMOTE_COMPUTER% >"%~dp0last.computer"
echo %REMOTE_TIMESTAMP% >"%~dp0last.timestamp"
SET REMOTE_PATH=
SET REMOTE_CMD=
SET REMOTE_LIST=
SET REMOTE_COMPUTER=
SET REMOTE_LOG=
SET REMOTE_TIMESTAMP=
ping -n 2 127.0.0.1 >nul
goto menu


:end
SET REMOTE_USER=
SET REMOTE_PASS=

ERROR 1698 (28000): Access denied for user 'root'@'localhost'

That worked for me:

mysql --user=root mysql
CREATE USER 'some_user'@'%' IDENTIFIED BY 'some_pass';
GRANT ALL PRIVILEGES ON *.* TO 'some_user'@'%' WITH GRANT OPTION;
FLUSH PRIVILEGES;

Killing a process created with Python's subprocess.Popen()

In your code it should be

proc1.kill()

Both kill or terminate are methods of the Popen object which sends the signal signal.SIGKILL to the process.

GetElementByID - Multiple IDs

The best way to do it, is to define a function, and pass it a parameter of the ID's name that you want to grab from the DOM, then every time you want to grab an ID and store it inside an array, then you can call the function

<p id="testing">Demo test!</p>

function grabbingId(element){
    var storeId = document.getElementById(element);

    return storeId;
}


grabbingId("testing").syle.color = "red";

How do I send a cross-domain POST request via JavaScript?

  1. Create an iFrame,
  2. put a form in it with Hidden inputs,
  3. set the form's action to the URL,
  4. Add iframe to document
  5. submit the form

Pseudocode

 var ifr = document.createElement('iframe');
 var frm = document.createElement('form');
 frm.setAttribute("action", "yoururl");
 frm.setAttribute("method", "post");

 // create hidden inputs, add them
 // not shown, but similar (create, setAttribute, appendChild)

 ifr.appendChild(frm);
 document.body.appendChild(ifr);
 frm.submit();

You probably want to style the iframe, to be hidden and absolutely positioned. Not sure cross site posting will be allowed by the browser, but if so, this is how to do it.

Pandas merge two dataframes with different columns

I think in this case concat is what you want:

In [12]:

pd.concat([df,df1], axis=0, ignore_index=True)
Out[12]:
   attr_1  attr_2  attr_3  id  quantity
0       0       1     NaN   1        20
1       1       1     NaN   2        23
2       1       1     NaN   3        19
3       0       0     NaN   4        19
4       1     NaN       0   5         8
5       0     NaN       1   6        13
6       1     NaN       1   7        20
7       1     NaN       1   8        25

by passing axis=0 here you are stacking the df's on top of each other which I believe is what you want then producing NaN value where they are absent from their respective dfs.

Accessing Google Account Id /username via Android

There is a sample from google, which lists the existing google accounts and generates an access token upon selection , you can send that access token to server to retrieve the related details from it to identify the user.

You can also get the email id from access token , for that you need to modify the SCOPE

Please go through My Post

What's the effect of adding 'return false' to a click event listener?

using return false in an onclick event stops the browser from processing the rest of the execution stack, which includes following the link in the href attribute.

In other words, adding return false stops the href from working. In your example, this is exactly what you want.

In buttons, it's not necessary because onclick is all it will ever execute -- there is no href to process and go to.

How to _really_ programmatically change primary and accent color in Android Lollipop?

I read the comments about contacts app and how it use a theme for each contact.

Probably, contacts app has some predefine themes (for each material primary color from here: http://www.google.com/design/spec/style/color.html).

You can apply a theme before a the setContentView method inside onCreate method.

Then the contacts app can apply a theme randomly to each user.

This method is:

setTheme(R.style.MyRandomTheme);

But this method has a problem, for example it can change the toolbar color, the scroll effect color, the ripple color, etc, but it cant change the status bar color and the navigation bar color (if you want to change it too).

Then for solve this problem, you can use the method before and:

if (Build.VERSION.SDK_INT >= 21) {
        getWindow().setNavigationBarColor(getResources().getColor(R.color.md_red_500));
        getWindow().setStatusBarColor(getResources().getColor(R.color.md_red_700));
    }

This two method change the navigation and status bar color. Remember, if you set your navigation bar translucent, you can't change its color.

This should be the final code:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setTheme(R.style.MyRandomTheme);
    if (Build.VERSION.SDK_INT >= 21) {
        getWindow().setNavigationBarColor(getResources().getColor(R.color.myrandomcolor1));
        getWindow().setStatusBarColor(getResources().getColor(R.color.myrandomcolor2));
    }
    setContentView(R.layout.activity_main);

}

You can use a switch and generate random number to use random themes, or, like in contacts app, each contact probably has a predefine number associated.

A sample of theme:

<style name="MyRandomTheme" parent="Theme.AppCompat.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/myrandomcolor1</item>
    <item name="colorPrimaryDark">@color/myrandomcolor2</item>
    <item name="android:navigationBarColor">@color/myrandomcolor1</item>
</style>

Sorry for my english.

ReactJS lifecycle method inside a function Component

If you need use React LifeCycle, you need use Class.

Sample:

import React, { Component } from 'react';

class Grid extends Component {

 constructor(props){
  super(props)
 }

 componentDidMount () { /* do something */ }

 render () { 
   return <h1>Hello</h1>
 }

}

How to wrap text in LaTeX tables?

With the regular tabular environment, you want to use the p{width} column type, as marcog indicates. But that forces you to give explicit widths.

Another solution is the tabularx environment:

\usepackage{tabularx}
...
\begin{tabularx}{\linewidth}{ r X }
    right-aligned foo & long long line of blah blah that will wrap when the table fills the column width\\
\end{tabularx}

All X columns get the same width. You can influence this by setting \hsize in the format declaration:

>{\setlength\hsize{.5\hsize}} X >{\setlength\hsize{1.5\hsize}} X

but then all the factors have to sum up to 1, I suppose (I took this from the LaTeX companion). There is also the package tabulary which will adjust column widths to balance row heights. For the details, you can get the documentation for each package with texdoc tabulary (in TeXlive).

how to rotate a bitmap 90 degrees

By default the rotation point is the Canvas's (0,0) point, and my guess is that you may want to rotate it around the center. I did that:

protected void renderImage(Canvas canvas)
{
    Rect dest,drawRect ;

    drawRect = new Rect(0,0, mImage.getWidth(), mImage.getHeight());
    dest = new Rect((int) (canvas.getWidth() / 2 - mImage.getWidth() * mImageResize / 2), // left
                    (int) (canvas.getHeight()/ 2 - mImage.getHeight()* mImageResize / 2), // top
                    (int) (canvas.getWidth() / 2 + mImage.getWidth() * mImageResize / 2), //right
                    (int) (canvas.getWidth() / 2 + mImage.getHeight()* mImageResize / 2));// bottom

    if(!mRotate) {
        canvas.drawBitmap(mImage, drawRect, dest, null);
    } else {
        canvas.save(Canvas.MATRIX_SAVE_FLAG); //Saving the canvas and later restoring it so only this image will be rotated.
        canvas.rotate(90,canvas.getWidth() / 2, canvas.getHeight()/ 2);
        canvas.drawBitmap(mImage, drawRect, dest, null);
        canvas.restore();
    }
}

Remove all spaces from a string in SQL Server

Try to use like this, if normal spaces are not removed by LTRM or RTRM

LTRIM(RTRIM(REPLACE(REPLACE(REPLACE(Column_data, CHAR(9), ''), CHAR(10), ''), CHAR(13), '')))

django import error - No module named core.management

If you are in a virtualenv you need to activate it before you can run ./manage.py 'command'

source path/to/your/virtualenv/bin/activate

if you config workon in .bash_profile or .bashrc

workon yourvirtualenvname

*please dont edit your manage.py file maybe works by isnt the correct way and could give you future errors

When to use HashMap over LinkedList or ArrayList and vice-versa

Lists and Maps are different data structures. Maps are used for when you want to associate a key with a value and Lists are an ordered collection.

Map is an interface in the Java Collection Framework and a HashMap is one implementation of the Map interface. HashMap are efficient for locating a value based on a key and inserting and deleting values based on a key. The entries of a HashMap are not ordered.

ArrayList and LinkedList are an implementation of the List interface. LinkedList provides sequential access and is generally more efficient at inserting and deleting elements in the list, however, it is it less efficient at accessing elements in a list. ArrayList provides random access and is more efficient at accessing elements but is generally slower at inserting and deleting elements.

What is the difference between Scope_Identity(), Identity(), @@Identity, and Ident_Current()?

  • The @@identity function returns the last identity created in the same session.
  • The scope_identity() function returns the last identity created in the same session and the same scope.
  • The ident_current(name) returns the last identity created for a specific table or view in any session.
  • The identity() function is not used to get an identity, it's used to create an identity in a select...into query.

The session is the database connection. The scope is the current query or the current stored procedure.

A situation where the scope_identity() and the @@identity functions differ, is if you have a trigger on the table. If you have a query that inserts a record, causing the trigger to insert another record somewhere, the scope_identity() function will return the identity created by the query, while the @@identity function will return the identity created by the trigger.

So, normally you would use the scope_identity() function.

find_spec_for_exe': can't find gem bundler (>= 0.a) (Gem::GemNotFoundException)

gem update --system

will update the rubygems and will fix the problem.

HTML: How to make a submit button with text + image in it?

You're really close to the answer yourself

<button type="submit">
<img src="save.gif" alt="Save icon"/>
<br/>
Save
</button>

Or, you can just remove the type-attribute

<button>
<img src="save.gif" alt="Save icon"/>
<br/>
Save
</button>

Error in contrasts when defining a linear model in R

From my experience ten minutes ago this situation can happen where there are more than one category but with a lot of NAs. Taking the Kaggle Houseprice Dataset as example, if you loaded data and run a simple regression,

train.df = read.csv('train.csv')
lm1 = lm(SalePrice ~ ., data = train.df)

you will get same error. I also tried testing the number of levels of each factor, but none of them says it has less than 2 levels.

cols = colnames(train.df)
for (col in cols){
  if(is.factor(train.df[[col]])){
    cat(col, ' has ', length(levels(train.df[[col]])), '\n')
  }
}

So after a long time I used summary(train.df) to see details of each col, and removed some, and it finally worked:

train.df = subset(train.df, select=-c(Id, PoolQC,Fence, MiscFeature, Alley, Utilities))
lm1 = lm(SalePrice ~ ., data = train.df)

and removing any one of them the regression fails to run again with same error (which I have tested myself).

And above attributes generally have 1400+ NAs and 10 useful values, so you might want to remove these garbage attributes, even they have 3 or 4 levels. I guess a function counting how many NAs in each column will help.

What are the differences between type() and isinstance()?

A practical usage difference is how they handle booleans:

True and False are just keywords that mean 1 and 0 in python. Thus,

isinstance(True, int)

and

isinstance(False, int)

both return True. Both booleans are an instance of an integer. type(), however, is more clever:

type(True) == int

returns False.

Command not found error in Bash variable assignment

Drop the spaces around the = sign:

#!/bin/bash 
STR="Hello World" 
echo $STR 

How to pass boolean parameter value in pipeline to downstream jobs?

like Jesse Jesse Glick and abguy said you can enumerate string into Boolean type:

Boolean.valueOf(string_variable)

or the opposite Boolean into string:

String.valueOf(boolean_variable)

in my case I had to to downstream Boolean parameter to another job. So for this you will need the use the class BooleanParameterValue :

build job: 'downstream_job_name', parameters:
[
[$class: 'BooleanParameterValue', name: 'parameter_name', value: false],
], wait: true

Volatile Vs Atomic

There are two important concepts in multithreading environment:

  1. atomicity
  2. visibility

The volatile keyword eradicates visibility problems, but it does not deal with atomicity. volatile will prevent the compiler from reordering instructions which involve a write and a subsequent read of a volatile variable; e.g. k++. Here, k++ is not a single machine instruction, but three:

  1. copy the value to a register;
  2. increment the value;
  3. place it back.

So, even if you declare a variable as volatile, this will not make this operation atomic; this means another thread can see a intermediate result which is a stale or unwanted value for the other thread.

On the other hand, AtomicInteger, AtomicReference are based on the Compare and swap instruction. CAS has three operands: a memory location V on which to operate, the expected old value A, and the new value B. CAS atomically updates V to the new value B, but only if the value in V matches the expected old value A; otherwise, it does nothing. In either case, it returns the value currently in V. The compareAndSet() methods of AtomicInteger and AtomicReference take advantage of this functionality, if it is supported by the underlying processor; if it is not, then the JVM implements it via spin lock.

How does one make random number between range for arc4random_uniform()?

The answer is just 1 line code:

let randomNumber = arc4random_uniform(8999) + 1000 //for 4 digit random number
let randomNumber = arc4random_uniform(899999999) + 100000000 //for 9 digit random number
let randomNumber = arc4random_uniform(89) + 10    //for 2 digit random number
let randomNumber = arc4random_uniform(899) + 100  //for 3 digit random number

The alternate solution is:

    func generateRandomNumber(numDigits: Int) -> Int{
    var place = 1
    var finalNumber = 0;
    var finanum = 0;
    for var i in 0 ..< numDigits {
        place *= 10
        let randomNumber = arc4random_uniform(10)         
        finalNumber += Int(randomNumber) * place
        finanum = finalNumber / 10
           i += 1
    }
    return finanum
}

Although the drawback is that number cannot start from 0.

How can I make a horizontal ListView in Android?

Gallery is the best solution, i have tried it. I was working on one mail app, in which mails in the inbox where displayed as listview, i wanted an horizontal view, i just converted listview to gallery and everything worked fine as i needed without any errors. For the scroll effect i enabled gesture listener for the gallery. I hope this answer may help u.

Use a.any() or a.all()

You comment:

valeur is a vector equal to [ 0. 1. 2. 3.] I am interested in each single term. For the part below 0.6, then return "this works"....

If you are interested in each term, then write the code so it deals with each. For example.

for b in valeur<=0.6:
    if b:
        print ("this works")
    else:   
        print ("valeur is too high")

This will write 2 lines.

The error is produced by numpy code when you try to use it a context that expects a single, scalar, value. if b:... can only do one thing. It does not, by itself, iterate through the elements of b doing a different thing for each.

You could also cast that iteration as list comprehension, e.g.

['yes' if b else 'no' for b in np.array([True, False, True])]

Token Authentication vs. Cookies

Token based authentication is stateless, server need not store user information in the session. This gives ability to scale application without worrying where the user has logged in. There is web Server Framework affinity for cookie based while that is not an issue with token based. So the same token can be used for fetching a secure resource from a domain other than the one we are logged in which avoids another uid/pwd authentication.

Very good article here:

http://www.toptal.com/web/cookie-free-authentication-with-json-web-tokens-an-example-in-laravel-and-angularjs

How can I create my own comparator for a map?

Since C++11, you can also use a lambda expression instead of defining a comparator struct:

auto comp = [](const string& a, const string& b) { return a.length() < b.length(); };
map<string, string, decltype(comp)> my_map(comp);

my_map["1"]      = "a";
my_map["three"]  = "b";
my_map["two"]    = "c";
my_map["fouuur"] = "d";

for(auto const &kv : my_map)
    cout << kv.first << endl;

Output:

1
two
three
fouuur

I'd like to repeat the final note of Georg's answer: When comparing by length you can only have one string of each length in the map as a key.

Code on Ideone

Where Is Machine.Config?

You can run this in powershell: copy & paste in power shell [System.Runtime.InteropServices.RuntimeEnvironment]::SystemConfigurationFile

mine output is: C:\Windows\Microsoft.NET\Framework\v2.0.50527\config\machine.config

How to check whether a string is Base64 encoded or not

This works in Python:

def is_base64(string):
    if len(string) % 4 == 0 and re.test('^[A-Za-z0-9+\/=]+\Z', string):
        return(True)
    else:
        return(False)

String in function parameter

char *arr; above statement implies that arr is a character pointer and it can point to either one character or strings of character

& char arr[]; above statement implies that arr is strings of character and can store as many characters as possible or even one but will always count on '\0' character hence making it a string ( e.g. char arr[]= "a" is similar to char arr[]={'a','\0'} )

But when used as parameters in called function, the string passed is stored character by character in formal arguments making no difference.

Java: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

This can also be caused by using GoDaddy certs with Java 7 that are signed using SHA2.

Chrome and all other browsers are starting to deprecate SSL certs that are signed using SHA1, as it's not as secure.

More info on the issue can be found here, as well as how to resolve it on your server if you need to now.

You have not concluded your merge (MERGE_HEAD exists)

Best approach is to undo the merge and perform the merge again. Often you get the order of things messed up. Try and fix the conflicts and get yourself into a mess.

So undo do it and merge again.

Make sure that you have the appropriate diff tools setup for your environment. I am on a mac and use DIFFMERGE. I think DIFFMERGE is available for all environments. Instructions are here: Install DIFF Merge on a MAC

I have this helpful resolving my conflicts: Git Basic-Merge-Conflicts

How do I find out which process is locking a file using .NET?

One of the good things about handle.exe is that you can run it as a subprocess and parse the output.

We do this in our deployment script - works like a charm.

How to display loading message when an iFrame is loading?

I have done the following css approach:

<div class="holds-the-iframe"><iframe here></iframe></div>

.holds-the-iframe {
  background:url(../images/loader.gif) center center no-repeat;
}

What ports need to be open for TortoiseSVN to authenticate (clear text) and commit?

What's the first part of your Subversion repository URL?

  • If your URL looks like: http://subversion/repos/, then you're probably going over Port 80.
  • If your URL looks like: https://subversion/repos/, then you're probably going over Port 443.
  • If your URL looks like: svn://subversion/, then you're probably going over Port 3690.
  • If your URL looks like: svn+ssh://subversion/repos/, then you're probably going over Port 22.
  • If your URL contains a port number like: http://subversion/repos:8080, then you're using that port.

I can't guarantee the first four since it's possible to reconfigure everything to use different ports, of if you go through a proxy of some sort.

If you're using a VPN, you may have to configure your VPN client to reroute these to their correct ports. A lot of places don't configure their correctly VPNs to do this type of proxying. It's either because they have some sort of anal-retentive IT person who's being overly security conscious, or because they simply don't know any better. Even worse, they'll give you a client where this stuff can't be reconfigured.

The only way around that is to log into a local machine over the VPN, and then do everything from that system.

How to use youtube-dl from a python program?

Here is a way.

We set-up options' string, in a list, just as we set-up command line arguments. In this case opts=['-g', 'videoID']. Then, invoke youtube_dl.main(opts). In this way, we write our custom .py module, import youtube_dl and then invoke the main() function.

How do I block comment in Jupyter notebook?

I am using chrome, Linux Mint; and for commenting and dis-commenting bundle of lines:

Ctrl + /

When & why to use delegates?

Delegates Overview

Delegates have the following properties:

  • Delegates are similar to C++ function pointers, but are type safe.
  • Delegates allow methods to be passed as parameters.
  • Delegates can be used to define callback methods.
  • Delegates can be chained together; for example, multiple methods can be called on a single event.
  • Methods don't need to match the delegate signature exactly. For more information, see Covariance and Contra variance.
  • C# version 2.0 introduces the concept of Anonymous Methods, which permit code blocks to be passed as parameters in place of a separately defined method.

How should I set the default proxy to use default credentials?

You may use Reflection to set the UseDefaultCredentials-Property from Code to "true"

System.Reflection.PropertyInfo pInfo = System.Net.WebRequest.DefaultWebProxy.GetType().GetProperty("WebProxy", 
System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);

((System.Net.WebProxy)pInfo.GetValue(System.Net.WebRequest.DefaultWebProxy, null)).UseDefaultCredentials = true;

How do I get the MAX row with a GROUP BY in LINQ query?

This can be done using GroupBy and SelectMany in LINQ lamda expression

var groupByMax = list.GroupBy(x=>x.item1).SelectMany(y=>y.Where(z=>z.item2 == y.Max(i=>i.item2)));

Unable to establish SSL connection, how do I fix my SSL cert?

SSL23_GET_SERVER_HELLO:unknown protocol

This error happens when OpenSSL receives something other than a ServerHello in a protocol version it understands from the server. It can happen if the server answers with a plain (unencrypted) HTTP. It can also happen if the server only supports e.g. TLS 1.2 and the client does not understand that protocol version. Normally, servers are backwards compatible to at least SSL 3.0 / TLS 1.0, but maybe this specific server isn't (by implementation or configuration).

It is unclear whether you attempted to pass --no-check-certificate or not. I would be rather surprised if that would work.

A simple test is to use wget (or a browser) to request http://example.com:443 (note the http://, not https://); if it works, SSL is not enabled on port 443. To further debug this, use openssl s_client with the -debug option, which right before the error message dumps the first few bytes of the server response which OpenSSL was unable to parse. This may help to identify the problem, especially if the server does not answer with a ServerHello message. To see what exactly OpenSSL is expecting, check the source: look for SSL_R_UNKNOWN_PROTOCOL in ssl/s23_clnt.c.

In any case, looking at the apache error log may provide some insight too.

How to replace list item in best way

Or, building on Rusian L.'s suggestion, if the item you're searching for can be in the list more than once::

[Extension()]
public void ReplaceAll<T>(List<T> input, T search, T replace)
{
    int i = 0;
    do {
        i = input.FindIndex(i, s => EqualityComparer<T>.Default.Equals(s, search));

        if (i > -1) {
            FileSystem.input(i) = replace;
            continue;
        }

        break;  
    } while (true);
}

apc vs eaccelerator vs xcache

In the end I went with eAccelerator - the speed boost, the smaller memory footprint and the fact that is was very easy to install swayed me. It also has a nice web-based front end to clear the cache and provide some stats.

The fact that its not maintained anymore is not an issue for me - it works, and that's all I care about. In the future, if it breaks PHP6 (or whatever), then I'll re-evaluate my decision and probably go with APC simply because its been adopted by the PHP developers (so should be even easier to install)

Regex expressions in Java, \\s vs. \\s+

First of all you need to understand that final output of both the statements will be same i.e. to remove all the spaces from given string.

However x.replaceAll("\\s+", ""); will be more efficient way of trimming spaces (if string can have multiple contiguous spaces) because of potentially less no of replacements due the to fact that regex \\s+ matches 1 or more spaces at once and replaces them with empty string.

So even though you get the same output from both it is better to use:

x.replaceAll("\\s+", "");

How do I manage MongoDB connections in a Node.js web application?

Here is some code that will manage your MongoDB connections.

var MongoClient = require('mongodb').MongoClient;
var url = require("../config.json")["MongoDBURL"]

var option = {
  db:{
    numberOfRetries : 5
  },
  server: {
    auto_reconnect: true,
    poolSize : 40,
    socketOptions: {
        connectTimeoutMS: 500
    }
  },
  replSet: {},
  mongos: {}
};

function MongoPool(){}

var p_db;

function initPool(cb){
  MongoClient.connect(url, option, function(err, db) {
    if (err) throw err;

    p_db = db;
    if(cb && typeof(cb) == 'function')
        cb(p_db);
  });
  return MongoPool;
}

MongoPool.initPool = initPool;

function getInstance(cb){
  if(!p_db){
    initPool(cb)
  }
  else{
    if(cb && typeof(cb) == 'function')
      cb(p_db);
  }
}
MongoPool.getInstance = getInstance;

module.exports = MongoPool;

When you start the server, call initPool

require("mongo-pool").initPool();

Then in any other module you can do the following:

var MongoPool = require("mongo-pool");
MongoPool.getInstance(function (db){
    // Query your MongoDB database.
});

This is based on MongoDB documentation. Take a look at it.

How can I replace non-printable Unicode characters in Java?

methods in blow for your goal

public static String removeNonAscii(String str)
{
    return str.replaceAll("[^\\x00-\\x7F]", "");
}

public static String removeNonPrintable(String str) // All Control Char
{
    return str.replaceAll("[\\p{C}]", "");
}

public static String removeSomeControlChar(String str) // Some Control Char
{
    return str.replaceAll("[\\p{Cntrl}\\p{Cc}\\p{Cf}\\p{Co}\\p{Cn}]", "");
}

public static String removeFullControlChar(String str)
{
    return removeNonPrintable(str).replaceAll("[\\r\\n\\t]", "");
} 

Redirecting Output from within Batch file

There is a cool little program you can use to redirect the output to a file and the console

some_command  ^|  TEE.BAT  [ -a ]  filename 

_x000D_
_x000D_
@ECHO OFF_x000D_
:: Check Windows version_x000D_
IF NOT "%OS%"=="Windows_NT" GOTO Syntax_x000D_
_x000D_
:: Keep variables local_x000D_
SETLOCAL_x000D_
_x000D_
:: Check command line arguments_x000D_
SET Append=0_x000D_
IF /I [%1]==[-a] (_x000D_
 SET Append=1_x000D_
 SHIFT_x000D_
)_x000D_
IF     [%1]==[] GOTO Syntax_x000D_
IF NOT [%2]==[] GOTO Syntax_x000D_
_x000D_
:: Test for invalid wildcards_x000D_
SET Counter=0_x000D_
FOR /F %%A IN ('DIR /A /B %1 2^>NUL') DO CALL :Count "%%~fA"_x000D_
IF %Counter% GTR 1 (_x000D_
 SET Counter=_x000D_
 GOTO Syntax_x000D_
)_x000D_
_x000D_
:: A valid filename seems to have been specified_x000D_
SET File=%1_x000D_
_x000D_
:: Check if a directory with the specified name exists_x000D_
DIR /AD %File% >NUL 2>NUL_x000D_
IF NOT ERRORLEVEL 1 (_x000D_
 SET File=_x000D_
 GOTO Syntax_x000D_
)_x000D_
_x000D_
:: Specify /Y switch for Windows 2000 / XP COPY command_x000D_
SET Y=_x000D_
VER | FIND "Windows NT" > NUL_x000D_
IF ERRORLEVEL 1 SET Y=/Y_x000D_
_x000D_
:: Flush existing file or create new one if -a wasn't specified_x000D_
IF %Append%==0 (COPY %Y% NUL %File% > NUL 2>&1)_x000D_
_x000D_
:: Actual TEE_x000D_
FOR /F "tokens=1* delims=]" %%A IN ('FIND /N /V ""') DO (_x000D_
 >  CON    ECHO.%%B_x000D_
 >> %File% ECHO.%%B_x000D_
)_x000D_
_x000D_
:: Done_x000D_
ENDLOCAL_x000D_
GOTO:EOF_x000D_
_x000D_
:Count_x000D_
SET /A Counter += 1_x000D_
SET File=%1_x000D_
GOTO:EOF_x000D_
_x000D_
:Syntax_x000D_
ECHO._x000D_
ECHO Tee.bat,  Version 2.11a for Windows NT 4 / 2000 / XP_x000D_
ECHO Display text on screen and redirect it to a file simultaneously_x000D_
ECHO._x000D_
IF NOT "%OS%"=="Windows_NT" ECHO Usage:  some_command  ³  TEE.BAT  [ -a ]  filename_x000D_
IF NOT "%OS%"=="Windows_NT" GOTO Skip_x000D_
ECHO Usage:  some_command  ^|  TEE.BAT  [ -a ]  filename_x000D_
:Skip_x000D_
ECHO._x000D_
ECHO Where:  "some_command" is the command whose output should be redirected_x000D_
ECHO         "filename"     is the file the output should be redirected to_x000D_
ECHO         -a             appends the output of the command to the file,_x000D_
ECHO                        rather than overwriting the file_x000D_
ECHO._x000D_
ECHO Written by Rob van der Woude_x000D_
ECHO http://www.robvanderwoude.com_x000D_
ECHO Modified by Kees Couprie_x000D_
ECHO http://kees.couprie.org_x000D_
ECHO and Andrew Cameron
_x000D_
_x000D_
_x000D_

How can I create a Windows .exe (standalone executable) using Java/Eclipse?

Creating .exe distributions isn't typical for Java. While such wrappers do exist, the normal mode of operation is to create a .jar file.

To create a .jar file from a Java project in Eclipse, use file->export->java->Jar file. This will create an archive with all your classes.

On the command prompt, use invocation like the following:

java -cp myapp.jar foo.bar.MyMainClass

JavaScript global event mechanism

You listen to the onerror event by assigning a function to window.onerror:

 window.onerror = function (msg, url, lineNo, columnNo, error) {
        var string = msg.toLowerCase();
        var substring = "script error";
        if (string.indexOf(substring) > -1){
            alert('Script Error: See Browser Console for Detail');
        } else {
            alert(msg, url, lineNo, columnNo, error);
        }   
      return false; 
  };

Combine two columns and add into one new column

Did you check the string concatenation function? Something like:

update table_c set column_a = column_b || column_c 

should work. More here

Using SHA1 and RSA with java.security.Signature vs. MessageDigest and Cipher

I have a similar problem, I tested adding code and found some interesting results. With this code I add, I can deduce that depending on the "provider" to use, the firm can be different? (because the data included in the encryption is not always equal in all providers).

Results of my test.

Conclusion.- Signature Decipher= ???(trash) + DigestInfo (if we know the value of "trash", the digital signatures will be equal)

IDE Eclipse OUTPUT...

Input data: This is the message being signed

Digest: 62b0a9ef15461c82766fb5bdaae9edbe4ac2e067

DigestInfo: 3021300906052b0e03021a0500041462b0a9ef15461c82766fb5bdaae9edbe4ac2e067

Signature Decipher: 1ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff003021300906052b0e03021a0500041462b0a9ef15461c82766fb5bdaae9edbe4ac2e067

CODE

import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import org.bouncycastle.asn1.x509.DigestInfo;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
public class prueba {
/**
* @param args
* @throws NoSuchProviderException 
* @throws NoSuchAlgorithmException 
* @throws InvalidKeyException 
* @throws SignatureException 
* @throws NoSuchPaddingException 
* @throws BadPaddingException 
* @throws IllegalBlockSizeException 
*///
public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchProviderException, InvalidKeyException, SignatureException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
// TODO Auto-generated method stub
KeyPair keyPair = KeyPairGenerator.getInstance("RSA","BC").generateKeyPair();
PrivateKey privateKey = keyPair.getPrivate();
PublicKey puKey = keyPair.getPublic();
String plaintext = "This is the message being signed";
// Hacer la firma
Signature instance = Signature.getInstance("SHA1withRSA","BC");
instance.initSign(privateKey);
instance.update((plaintext).getBytes());
byte[] signature = instance.sign();
// En dos partes primero hago un Hash
MessageDigest digest = MessageDigest.getInstance("SHA1", "BC");
byte[] hash = digest.digest((plaintext).getBytes());
// El digest es identico a  openssl dgst -sha1 texto.txt
//MessageDigest sha1 = MessageDigest.getInstance("SHA1","BC");
//byte[] digest = sha1.digest((plaintext).getBytes());
AlgorithmIdentifier digestAlgorithm = new AlgorithmIdentifier(new
DERObjectIdentifier("1.3.14.3.2.26"), null);
// create the digest info
DigestInfo di = new DigestInfo(digestAlgorithm, hash);
byte[] digestInfo = di.getDEREncoded();
//Luego cifro el hash
Cipher cipher = Cipher.getInstance("RSA","BC");
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] cipherText = cipher.doFinal(digestInfo);
//byte[] cipherText = cipher.doFinal(digest2);
Cipher cipher2 = Cipher.getInstance("RSA","BC");
cipher2.init(Cipher.DECRYPT_MODE, puKey);
byte[] cipherText2 = cipher2.doFinal(signature);
System.out.println("Input data: " + plaintext);
System.out.println("Digest: " + bytes2String(hash));
System.out.println("Signature: " + bytes2String(signature));
System.out.println("Signature2: " + bytes2String(cipherText));
System.out.println("DigestInfo: " + bytes2String(digestInfo));
System.out.println("Signature Decipher: " + bytes2String(cipherText2));
}

React Js conditionally applying class attributes

I would like to add that you can also use a variable content as a part of the class

<img src={src} alt="Avatar" className={"img-" + messages[key].sender} />

The context is a chat between a bot and a user, and the styles change depending of the sender, this is the browser result:

<img src="http://imageurl" alt="Avatar" class="img-bot">

How to set the 'selected option' of a select dropdown list with jquery

Try this :

$('select[name^="salesrep"] option[value="Bruce Jones"]').attr("selected","selected");

Just replace option[value="Bruce Jones"] by option[value=result[0]]

And before selecting a new option, you might want to "unselect" the previous :

$('select[name^="salesrep"] option:selected').attr("selected",null);

You may want to read this too : jQuery get specific option tag text

Edit: Using jQuery Mobile, this link may provide a good solution : jquery mobile - set select/option values

Java generics - ArrayList initialization

You have strange expectations. If you gave the chain of arguments that led you to them, we might spot the flaw in them. As it is, I can only give a short primer on generics, hoping to touch on the points you might have misunderstood.

ArrayList<? extends Object> is an ArrayList whose type parameter is known to be Object or a subtype thereof. (Yes, extends in type bounds has a meaning other than direct subclass). Since only reference types can be type parameters, this is actually equivalent to ArrayList<?>.

That is, you can put an ArrayList<String> into a variable declared with ArrayList<?>. That's why a1.add(3) is a compile time error. a1's declared type permits a1 to be an ArrayList<String>, to which no Integer can be added.

Clearly, an ArrayList<?> is not very useful, as you can only insert null into it. That might be why the Java Spec forbids it:

It is a compile-time error if any of the type arguments used in a class instance creation expression are wildcard type arguments

ArrayList<ArrayList<?>> in contrast is a functional data type. You can add all kinds of ArrayLists into it, and retrieve them. And since ArrayList<?> only contains but is not a wildcard type, the above rule does not apply.

Warning: require_once(): http:// wrapper is disabled in the server configuration by allow_url_include=0

I had this same error while trying to include a PHP file in my Wordpress theme. I was able to get around it by referencing the file name using dirname(__FILE__). I couldn't use relative paths since my file was going to be included in different places throughout the theme, so something like require_once '../path-to/my-file' wouldn't work.

Replacing require_once get_template_directory_uri() . '/path-to/my-file' with require_once dirname( __FILE__ ) . '/path-to/my-file' did the trick.

Java for loop multiple variables

  1. It is cards.length(), not cards.length (length is a method of java.lang.String, not an attribute).

  2. It is System.out (capital 's'), not system.out. See java.lang.System.

  3. It is

    for(int a = 0, b = 1; a<cards.length()-1; b=a+1, a++){
    

    not

    for(int a = 0, b = 1; a<cards.length-1; b=a+1; a++;){
    
  4. Syntactically, it is if(rank == cards.substring(a,b)){, not if(rank===cards.substring(a,b){ (double equals, not triple equals; missing closing parenthesis), but to compare if two Strings are equal you need to use equals(): if(rank.equals(cards.substring(a,b))){

You should probably consider downloading Eclipse, which is an integrated development environment (not only) for Java development. Eclipse shows you the errors while you type and also provides help in fixing these. This makes it much easier to get started with Java development.

How do I write to a Python subprocess' stdin?

It might be better to use communicate:

from subprocess import Popen, PIPE, STDOUT
p = Popen(['myapp'], stdout=PIPE, stdin=PIPE, stderr=PIPE)
stdout_data = p.communicate(input='data_to_write')[0]

"Better", because of this warning:

Use communicate() rather than .stdin.write, .stdout.read or .stderr.read to avoid deadlocks due to any of the other OS pipe buffers filling up and blocking the child process.

How to use GROUP_CONCAT in a CONCAT in MySQL

IF OBJECT_ID('master..test') is not null Drop table test

CREATE TABLE test (ID INTEGER, NAME VARCHAR (50), VALUE INTEGER );
INSERT INTO test VALUES (1, 'A', 4);
INSERT INTO test VALUES (1, 'A', 5);
INSERT INTO test VALUES (1, 'B', 8);
INSERT INTO test VALUES (2, 'C', 9);

select distinct NAME , LIST = Replace(Replace(Stuff((select ',', +Value from test where name = _a.name for xml path('')), 1,1,''),'<Value>', ''),'</Value>','') from test _a order by 1 desc

My table name is test , and for concatination I use the For XML Path('') syntax. The stuff function inserts a string into another string. It deletes a specified length of characters in the first string at the start position and then inserts the second string into the first string at the start position.

STUFF functions looks like this : STUFF (character_expression , start , length ,character_expression )

character_expression Is an expression of character data. character_expression can be a constant, variable, or column of either character or binary data.

start Is an integer value that specifies the location to start deletion and insertion. If start or length is negative, a null string is returned. If start is longer than the first character_expression, a null string is returned. start can be of type bigint.

length Is an integer that specifies the number of characters to delete. If length is longer than the first character_expression, deletion occurs up to the last character in the last character_expression. length can be of type bigint.

how to access the command line for xampp on windows

Xampp has the php application under: C:\xampp\php file directory ... if you input C:\xampp\php\php in CMD it should enter the php application.

How to check whether a file is empty or not?

import os    
os.path.getsize(fullpathhere) > 0

Convert php array to Javascript

For a multidimensional array in PHP4 you can use the following addition to the code posted by Udo G:

function js_str($s) {
   return '"'.addcslashes($s, "\0..\37\"\\").'"';
}

function js_array($array, $keys_array) {
  foreach ($array as $key => $value) {
    $new_keys_array = $keys_array;
    $new_keys_array[] = $key;
    if(is_array($value)) {          
      echo 'javascript_array';
      foreach($new_keys_array as $key) {
        echo '["'.$key.'"]';
      }
      echo ' = new Array();';

      js_array($value, $new_keys_array);
    } else {
      echo 'javascript_array';
      foreach($new_keys_array as $key) {
        echo '["'.$key.'"]';
      }
      echo ' = '.js_str($value).";";                        
    }
  } 
}

echo 'var javascript_array = new Array();';
js_array($php_array, array());

Import local function from a module housed in another directory with relative imports in Jupyter Notebook using Python 3

Came here searching for best practices in abstracting code to submodules when working in Notebooks. I'm not sure that there is a best practice. I have been proposing this.

A project hierarchy as such:

+-- ipynb
¦   +-- 20170609-Examine_Database_Requirements.ipynb
¦   +-- 20170609-Initial_Database_Connection.ipynb
+-- lib
    +-- __init__.py
    +-- postgres.py

And from 20170609-Initial_Database_Connection.ipynb:

    In [1]: cd ..

    In [2]: from lib.postgres import database_connection

This works because by default the Jupyter Notebook can parse the cd command. Note that this does not make use of Python Notebook magic. It simply works without prepending %bash.

Considering that 99 times out of a 100 I am working in Docker using one of the Project Jupyter Docker images, the following modification is idempotent

    In [1]: cd /home/jovyan

    In [2]: from lib.postgres import database_connection

Git: add vs push vs commit

add -in git is used to tell git which files we want to commit, it puts files to the staging area

commit- in git is used to save files on to local machine so that if we make any changes or even delete the files we can still recover our committed files

push - if we commit our files on the local machine they are still prone to be lost if our local machine gets lost, gets damaged, etc, to keep our files safe or to share our files usually we want to keep our files on a remote repository like Github. To save on remote repositories we use push

example Staging a file named index.html git add index.html

Committing a file that is staged git commit -m 'name of your commit'

Pushing a file to Github git push origin master

Your project contains error(s), please fix it before running it

Simply Deleted my debug certificate under ~/.android/debug.keystore and Project->Clean did solve the problem.

PHP: Split a string in to an array foreach char

You can access a string using [], as you do for arrays:

$stringLength = strlen($str);
for ($i = 0; $i < $stringLength; $i++)
    $char = $str[$i];

Retrieving a property of a JSON object by index?

I know this is an old question but I found a way to get the fields by index. You can do it by using the Object.keys method.

When you call the Object.keys method it returns the keys in the order they were assigned (See the example below). I tested the method below in the following browsers:

  • Google Chrome version 43.0
  • Firefox version 33.1
  • Internet Explorer version 11

I also wrote a small extension to the object class so you can call the nth key of the object using getByIndex.

_x000D_
_x000D_
// Function to get the nth key from the object_x000D_
Object.prototype.getByIndex = function(index) {_x000D_
  return this[Object.keys(this)[index]];_x000D_
};_x000D_
_x000D_
var obj1 = {_x000D_
  "set1": [1, 2, 3],_x000D_
  "set2": [4, 5, 6, 7, 8],_x000D_
  "set3": [9, 10, 11, 12]_x000D_
};_x000D_
_x000D_
var obj2 = {_x000D_
  "set2": [4, 5, 6, 7, 8],_x000D_
  "set1": [1, 2, 3],_x000D_
  "set3": [9, 10, 11, 12]_x000D_
};_x000D_
_x000D_
log('-- Obj1 --');_x000D_
log(obj1);_x000D_
log(Object.keys(obj1));_x000D_
log(obj1.getByIndex(0));_x000D_
_x000D_
_x000D_
log('-- Obj2 --');_x000D_
log(obj2);_x000D_
log(Object.keys(obj2));_x000D_
log(obj2.getByIndex(0));_x000D_
_x000D_
_x000D_
// Log function to make the snippet possible_x000D_
function log(x) {_x000D_
  var d = document.createElement("div");_x000D_
  if (typeof x === "object") {_x000D_
    x = JSON.stringify(x, null, 4);_x000D_
  }_x000D_
  d.textContent= x;_x000D_
  document.body.appendChild(d);_x000D_
}
_x000D_
_x000D_
_x000D_

Escaping ampersand character in SQL string

REPLACE(<your xml column>,'&',chr(38)||'amp;')

scroll image with continuous scrolling using marquee tag

Try this:

<marquee behavior="" Height="200px"  direction="up" scroll onmouseover="this.setAttribute('scrollamount', 0, 0);this.stop();" onmouseout="this.setAttribute('scrollamount', 3, 0);this.start();" scrollamount="3" valign="center">

    <img src="images/a.jpg">
        <img src="images/a.jpg">
        <img src="images/a.jpg">
        <img src="images/a.jpg">
        <img src="images/a.jpg">
        <img src="images/a.jpg">
    </marquee>

Saving response from Requests to file

I believe all the existing answers contain the relevant information, but I would like to summarize.

The response object that is returned by requests get and post operations contains two useful attributes:

Response attributes

  • response.text - Contains str with the response text.
  • response.content - Contains bytes with the raw response content.

You should choose one or other of these attributes depending on the type of response you expect.

  • For text-based responses (html, json, yaml, etc) you would use response.text
  • For binary-based responses (jpg, png, zip, xls, etc) you would use response.content.

Writing response to file

When writing responses to file you need to use the open function with the appropriate file write mode.

  • For text responses you need to use "w" - plain write mode.
  • For binary responses you need to use "wb" - binary write mode.

Examples

Text request and save

# Request the HTML for this web page:
response = requests.get("https://stackoverflow.com/questions/31126596/saving-response-from-requests-to-file")
with open("response.txt", "w") as f:
    f.write(response.text)

Binary request and save

# Request the profile picture of the OP:
response = requests.get("https://i.stack.imgur.com/iysmF.jpg?s=32&g=1")
with open("response.jpg", "wb") as f:
    f.write(response.content)

Answering the original question

The original code should work by using wb and response.content:

import requests

files = {'f': ('1.pdf', open('1.pdf', 'rb'))}
response = requests.post("https://pdftables.com/api?&format=xlsx-single",files=files)
response.raise_for_status() # ensure we notice bad responses
file = open("out.xls", "wb")
file.write(response.content)
file.close()

But I would go further and use the with context manager for open.

import requests

with open('1.pdf', 'rb') as file:
    files = {'f': ('1.pdf', file)}
    response = requests.post("https://pdftables.com/api?&format=xlsx-single",files=files)

response.raise_for_status() # ensure we notice bad responses

with open("out.xls", "wb") as file:
    file.write(response.content)

Use jQuery to hide a DIV when the user clicks outside of it

Built off of prc322's awesome answer.

function hideContainerOnMouseClickOut(selector, callback) {
  var args = Array.prototype.slice.call(arguments); // Save/convert arguments to array since we won't be able to access these within .on()
  $(document).on("mouseup.clickOFF touchend.clickOFF", function (e) {
    var container = $(selector);

    if (!container.is(e.target) // if the target of the click isn't the container...
        && container.has(e.target).length === 0) // ... nor a descendant of the container
    {
      container.hide();
      $(document).off("mouseup.clickOFF touchend.clickOFF");
      if (callback) callback.apply(this, args);
    }
  });
}

This adds a couple things...

  1. Placed within a function with a callback with "unlimited" args
  2. Added a call to jquery's .off() paired with a event namespace to unbind the event from the document once it's been run.
  3. Included touchend for mobile functionality

I hope this helps someone!

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

Better solution is to use NZ (null to zero) function during generating table => NZ([ColumnName]) It comes 0 where is "null" in ColumnName.

Critical t values in R

Extending @Ryogi answer above, you can take advantage of the lower.tail parameter like so:

qt(0.25/2, 40, lower.tail = FALSE) # 75% confidence

qt(0.01/2, 40, lower.tail = FALSE) # 99% confidence

IE8 support for CSS Media Query

Internet Explorer versions before IE9 do not support media queries.

If you are looking for a way of degrading the design for IE8 users, you may find IE's conditional commenting helpful. Using this, you can specify an IE 8/7/6 specific style sheet which over writes the previous rules.

For example:

<link rel="stylesheet" type="text/css" media="all" href="style.css"/>
<!--[if lt IE 9]>
<link rel="stylesheet" type="text/css" media="all" href="style-ie.css"/>
<![endif]-->

This won't allow for a responsive design in IE8, but could be a simpler and more accessible solution than using a JS plugin.

File is universal (three slices), but it does not contain a(n) ARMv7-s slice error for static libraries on iOS, anyway to bypass?

I just posted a fix here that would also apply in this case - basically, you do a hex find-and-replace in your external library to make it think that it's ARMv7s code. You should be able to use lipo to break it into 3 static libraries, duplicate / modify the ARMv7 one, then use lipo again to assemble a new library for all 4 architectures.

jQuery load first 3 elements, click "load more" to display next 5 elements

Simple and with little changes. And also hide load more when entire list is loaded.

jsFiddle here.

$(document).ready(function () {
    // Load the first 3 list items from another HTML file
    //$('#myList').load('externalList.html li:lt(3)');
    $('#myList li:lt(3)').show();
    $('#showLess').hide();
    var items =  25;
    var shown =  3;
    $('#loadMore').click(function () {
        $('#showLess').show();
        shown = $('#myList li:visible').size()+5;
        if(shown< items) {$('#myList li:lt('+shown+')').show();}
        else {$('#myList li:lt('+items+')').show();
             $('#loadMore').hide();
             }
    });
    $('#showLess').click(function () {
        $('#myList li').not(':lt(3)').hide();
    });
});

What's the advantage of a Java enum versus a class with public static final fields?

The biggest advantage is enum Singletons are easy to write and thread-safe :

public enum EasySingleton{
    INSTANCE;
}

and

/**
* Singleton pattern example with Double checked Locking
*/
public class DoubleCheckedLockingSingleton{
     private volatile DoubleCheckedLockingSingleton INSTANCE;

     private DoubleCheckedLockingSingleton(){}

     public DoubleCheckedLockingSingleton getInstance(){
         if(INSTANCE == null){
            synchronized(DoubleCheckedLockingSingleton.class){
                //double checking Singleton instance
                if(INSTANCE == null){
                    INSTANCE = new DoubleCheckedLockingSingleton();
                }
            }
         }
         return INSTANCE;
     }
}

both are similar and it handled Serialization by themselves by implementing

//readResolve to prevent another instance of Singleton
    private Object readResolve(){
        return INSTANCE;
    }

more

Why are the Level.FINE logging messages not showing?

Loggers only log the message, i.e. they create the log records (or logging requests). They do not publish the messages to the destinations, which is taken care of by the Handlers. Setting the level of a logger, only causes it to create log records matching that level or higher.

You might be using a ConsoleHandler (I couldn't infer where your output is System.err or a file, but I would assume that it is the former), which defaults to publishing log records of the level Level.INFO. You will have to configure this handler, to publish log records of level Level.FINER and higher, for the desired outcome.

I would recommend reading the Java Logging Overview guide, in order to understand the underlying design. The guide covers the difference between the concept of a Logger and a Handler.

Editing the handler level

1. Using the Configuration file

The java.util.logging properties file (by default, this is the logging.properties file in JRE_HOME/lib) can be modified to change the default level of the ConsoleHandler:

java.util.logging.ConsoleHandler.level = FINER

2. Creating handlers at runtime

This is not recommended, for it would result in overriding the global configuration. Using this throughout your code base will result in a possibly unmanageable logger configuration.

Handler consoleHandler = new ConsoleHandler();
consoleHandler.setLevel(Level.FINER);
Logger.getAnonymousLogger().addHandler(consoleHandler);

How to get rid of punctuation using NLTK tokenizer?

You do not really need NLTK to remove punctuation. You can remove it with simple python. For strings:

import string
s = '... some string with punctuation ...'
s = s.translate(None, string.punctuation)

Or for unicode:

import string
translate_table = dict((ord(char), None) for char in string.punctuation)   
s.translate(translate_table)

and then use this string in your tokenizer.

P.S. string module have some other sets of elements that can be removed (like digits).

What does the line "#!/bin/sh" mean in a UNIX shell script?

When you try to execute a program in unix (one with the executable bit set), the operating system will look at the first few bytes of the file. These form the so-called "magic number", which can be used to decide the format of the program and how to execute it.

#! corresponds to the magic number 0x2321 (look it up in an ascii table). When the system sees that the magic number, it knows that it is dealing with a text script and reads until the next \n (there is a limit, but it escapes me atm). Having identified the interpreter (the first argument after the shebang) it will call the interpreter.

Other files also have magic numbers. Try looking at a bitmap (.BMP) file via less and you will see the first two characters are BM. This magic number denotes that the file is indeed a bitmap.

In MVC, how do I return a string result?

public JsonResult GetAjaxValue() 
{
  return Json("string value", JsonRequetBehaviour.Allowget); 
}

Javascript: formatting a rounded number to N decimals

I think that there is a more simple approach to all given here, and is the method Number.toFixed() already implemented in JavaScript.

simply write:

var myNumber = 2;

myNumber.toFixed(2); //returns "2.00"
myNumber.toFixed(1); //returns "2.0"

etc...

Available text color classes in Bootstrap

You can use text classes:

.text-primary
.text-secondary
.text-success
.text-danger
.text-warning
.text-info
.text-light
.text-dark
.text-muted
.text-white

use text classes in any tag where needed.

<p class="text-primary">.text-primary</p>
<p class="text-secondary">.text-secondary</p>
<p class="text-success">.text-success</p>
<p class="text-danger">.text-danger</p>
<p class="text-warning">.text-warning</p>
<p class="text-info">.text-info</p>
<p class="text-light bg-dark">.text-light</p>
<p class="text-dark">.text-dark</p>
<p class="text-muted">.text-muted</p>
<p class="text-white bg-dark">.text-white</p>

You can add your own classes or modify above classes as your requirement.

Bad operand type for unary +: 'str'

The code works for me. (after adding missing except clause / import statements)

Did you put \ in the original code?

urlToVisit = 'http://chartapi.finance.yahoo.com/instrument/1.0/' \
              + stock + '/chartdata;type=quote;range=5d/csv'

If you omit it, it could be a cause of the exception:

>>> stock = 'GOOG'
>>> urlToVisit = 'http://chartapi.finance.yahoo.com/instrument/1.0/'
>>> + stock + '/chartdata;type=quote;range=5d/csv'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: bad operand type for unary +: 'str'

BTW, string(e) should be str(e).

How do I make a div full screen?

This is the simplest one.

#divid {
   position: fixed;
   top: 0;
   right: 0;
   bottom: 0;
   left: 0;
}

Build unsigned APK file with Android Studio

I would recommend you to build your APK file with Gradle:

  • Click the dropdown menu in the toolbar at the top (Open 'Edit Run/Debug configurations' dialog)
  • Select "Edit Configurations"
  • Click the "+"
  • Select "Gradle"
  • Choose your module as a Gradle project
  • In Tasks: enter assemble
  • Press Run

Your unsigned APK is now located in

ProjectName\app\build\outputs\apk

For detailed information on how to use Gradle, this tutorial is good to go: Building with Gradle in Android Studio. I also wrote a blog post on how to build an unsigned APK with Gradle.

If you moved your project from the other IDE and don't want to recompile, you may find your APK file that was already built in the IDE you moved from:

  • If you generated the Project with Android Studio, the APK file will be found in ProjectName/ProjectName/build/apk/...

  • Imported the project from eclipse: File should be in the same directory. Go to Project - Show in Explorer. There you should find the bin folder where your APK file is located in.

  • Imported from IntelliJ, the location would be ProjectName/out/production/...

Side note: As Chris Stratton mentioned in his comment:

Technically, what you want is an APK signed with a debug key. An APK that is actually unsigned will be refused by the device.

How do I insert non breaking space character &nbsp; in a JSF page?

Eventually, you can try this one, if just using &nbsp; fails...

<h:outputText value="& nbsp;" escape="false"/>

(like Tom, I added a space between & and nbsp; )

Ignore mapping one property with Automapper

You can do this:

conf.CreateMap<SourceType, DestinationType>()
   .ForSourceMember(x => x.SourceProperty, y => y.Ignore());

Or, in latest version of Automapper, you simply want to tell Automapper to not validate the field

conf.CreateMap<SourceType, DestinationType>()
   .ForSourceMember(x => x.SourceProperty, y => y.DoNotValidate());

dismissModalViewControllerAnimated deprecated

The new method is:

[self dismissViewControllerAnimated:NO completion:nil];

The word modal has been removed; As it has been for the presenting API call:

[self presentViewController:vc animated:NO completion:nil];

The reasons were discussed in the 2012 WWDC Session 236 - The Evolution of View Controllers on iOS Video. Essentially, view controllers presented by this API are no longer always modal, and since they were adding a completion handler it was a good time to rename it.

In response to comment from Marc:

What's the best way to support all devices 4.3 and above? The new method doesn't work in iOS4, yet the old method is deprecated in iOS6.

I realize that this is almost a separate question, but I think it's worth a mention since not everyone has the money to upgrade all their devices every 3 years so many of us have some older (pre 5.0) devices. Still, as much as it pains me to say it, you need to consider if it is worth targeting below 5.0. There are many new and cool APIs not available below 5.0. And Apple is continually making it harder to target them; armv6 support is dropped from Xcode 4.5, for example.

To target below 5.0 (as long as the completion block is nil) just use the handy respondsToSelector: method.

if ([self respondsToSelector:@selector(presentViewController:animated:completion:)]){
    [self presentViewController:test animated:YES completion:nil];
} else {
    [self presentModalViewController:test animated:YES];
}

In response to another comment from Marc:

That could be quite a lot of If statements in my application!...I was thinking of creating a category that encapsulated this code, would creating a category on UIViewControler get me rejected?

and one from Full Decent:

...is there a way to manually cause that to not present a compiler warning?

Firstly, no, creating a category on UIViewController in and of itself will not get your app rejected; unless that category method called private APIs or something similar.

A category method is an exceedingly good place for such code. Also, since there would be only one call to the deprecated API, there would be only one compiler warning.

To address Full Decent's comment(question), yes you can suppress compiler warnings manually. Here is a link to an answer on SO on that very subject. A category method is also a great place to suppress a compiler warning, since you're only suppressing the warning in one place. You certainly don't want to go around silencing the compiler willy-nilly.

If I was to write a simple category method for this it might be something like this:

@implementation UIViewController (NJ_ModalPresentation)
-(void)nj_presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)flag completion:(void (^)(void))completion{
    NSAssert(completion == nil, @"You called %@ with a non-nil completion. Don't do that!",NSStringFromSelector(_cmd));
    if ([self respondsToSelector:@selector(presentViewController:animated:completion:)]){
        [self presentViewController:viewControllerToPresent animated:flag completion:completion];
    } else {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
        [self presentModalViewController:viewControllerToPresent animated:flag];
#pragma clang diagnostic pop
    }
}
@end

How can I reverse a NSArray in Objective-C?

After reviewing the other's answers above and finding Matt Gallagher's discussion here

I propose this:

NSMutableArray * reverseArray = [NSMutableArray arrayWithCapacity:[myArray count]]; 

for (id element in [myArray reverseObjectEnumerator]) {
    [reverseArray addObject:element];
}

As Matt observes:

In the above case, you may wonder if -[NSArray reverseObjectEnumerator] would be run on every iteration of the loop — potentially slowing down the code. <...>

Shortly thereafter, he answers thus:

<...> The "collection" expression is only evaluated once, when the for loop begins. This is the best case, since you can safely put an expensive function in the "collection" expression without impacting upon the per-iteration performance of the loop.

How to remove all click event handlers using jQuery?

Is there a way to remove all previous click events that have been assigned to a button?

$('#saveBtn').unbind('click').click(function(){saveQuestion(id)});

How to download file in swift?

You can also use a third party library that makes life easy, like Just

Just.get("http://www.mywebsite.com/myfile.pdf")

More awesome Swift stuff here https://github.com/matteocrippa/awesome-swift

Make 2 functions run at the same time

This can be done elegantly with Ray, a system that allows you to easily parallelize and distribute your Python code.

To parallelize your example, you'd need to define your functions with the @ray.remote decorator, and then invoke them with .remote.

import ray

ray.init()

# Define functions you want to execute in parallel using 
# the ray.remote decorator.
@ray.remote
def func1():
    print("Working")

@ray.remote
def func2():
    print("Working")

# Execute func1 and func2 in parallel.
ray.get([func1.remote(), func2.remote()])

If func1() and func2() return results, you need to rewrite the above code a bit, by replacing ray.get([func1.remote(), func2.remote()]) with:

ret_id1 = func1.remote()
ret_id2 = func1.remote()
ret1, ret2 = ray.get([ret_id1, ret_id2])

There are a number of advantages of using Ray over the multiprocessing module or using multithreading. In particular, the same code will run on a single machine as well as on a cluster of machines.

For more advantages of Ray see this related post.

How to draw a line in android

this code adds horizontal line to a linear layout

View view = new View(this);
LinearLayout.LayoutParams lpView = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, 1); // --> horizontal
view.setLayoutParams(lpView);
view.setBackgroundColor(Color.DKGRAY);

linearLayout.addView(view);

Replace characters from a column of a data frame R

If your variable data1$c is a factor, it's more efficient to change the labels of the factor levels than to create a new vector of characters:

levels(data1$c) <- sub("_", "-", levels(data1$c))


            a b   c
1  0.73945260 a A-B
2  0.75998815 b A-B
3  0.19576725 c A-B
4  0.85932140 d A-B
5  0.80717115 e A-C
6  0.09101492 f A-C
7  0.10183586 g A-C
8  0.97742424 h A-C
9  0.21364521 i A-C
10 0.02389782 j A-C

How to set environment variables in Jenkins?

This is the snippet to store environment variable and access it.

node {
   withEnv(["ENABLE_TESTS=true", "DISABLE_SQL=false"]) {
      stage('Select Jenkinsfile') {
          echo "Enable test?: ${env.DEVOPS_SKIP_TESTS}
          customStep script: this
      }
   }
}

Note: The value of environment variable is coming as a String. If you want to use it as a boolean then you have to parse it using Boolean.parse(env.DISABLE_SQL).

Android ListView selected item stay highlighted

listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

            for (int j = 0; j < adapterView.getChildCount(); j++)
                adapterView.getChildAt(j).setBackgroundColor(Color.TRANSPARENT);

            // change the background color of the selected element
            view.setBackgroundColor(Color.LTGRAY);
});

Perhaps you might want to save the current selected element in a global variable using the index i.

How to determine if binary tree is balanced?

Wouldn't this work?

return ( ( Math.abs( size( root.left ) - size( root.right ) ) < 2 );

Any unbalanced tree would always fail this.

What is the functionality of setSoTimeout and how it works?

The JavaDoc explains it very well:

With this option set to a non-zero timeout, a read() call on the InputStream associated with this Socket will block for only this amount of time. If the timeout expires, a java.net.SocketTimeoutException is raised, though the Socket is still valid. The option must be enabled prior to entering the blocking operation to have effect. The timeout must be > 0. A timeout of zero is interpreted as an infinite timeout.

SO_TIMEOUT is the timeout that a read() call will block. If the timeout is reached, a java.net.SocketTimeoutException will be thrown. If you want to block forever put this option to zero (the default value), then the read() call will block until at least 1 byte could be read.

Hibernate problem - "Use of @OneToMany or @ManyToMany targeting an unmapped class"

Mine was not having @Entity on the many side entity

@Entity // this was commented
@Table(name = "some_table")
public class ChildEntity {
    @JoinColumn(name = "parent", referencedColumnName = "id")
    @ManyToOne
    private ParentEntity parentEntity;
}

Get the last element of a std::string

You probably want to check the length of the string first and do something like this:

if (!myStr.empty())
{
    char lastChar = *myStr.rbegin();
}