Programs & Examples On #Object properties

How to create a new instance from a class object in Python

This is how you can dynamically create a class named Child in your code, assuming Parent already exists... even if you don't have an explicit Parent class, you could use object...

The code below defines __init__() and then associates it with the class.

>>> child_name = "Child"
>>> child_parents = (Parent,)
>>> child body = """
def __init__(self, arg1):
    # Initialization for the Child class
    self.foo = do_something(arg1)
"""
>>> child_dict = {}
>>> exec(child_body, globals(), child_dict)
>>> childobj = type(child_name, child_parents, child_dict)
>>> childobj.__name__
'Child'
>>> childobj.__bases__
(<type 'object'>,)
>>> # Instantiating the new Child object...
>>> childinst = childobj()
>>> childinst
<__main__.Child object at 0x1c91710>
>>>

How to check that a JCheckBox is checked?

Use the isSelected method.

You can also use an ItemListener so you'll be notified when it's checked or unchecked.

Apply a theme to an activity in Android?

To set it programmatically in Activity.java:

public void onCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

  setTheme(R.style.MyTheme); // (for Custom theme)
  setTheme(android.R.style.Theme_Holo); // (for Android Built In Theme)

  this.setContentView(R.layout.myactivity);

To set in Application scope in Manifest.xml (all activities):

 <application
    android:theme="@android:style/Theme.Holo"
    android:theme="@style/MyTheme">

To set in Activity scope in Manifest.xml (single activity):

  <activity
    android:theme="@android:style/Theme.Holo"
    android:theme="@style/MyTheme">

To build a custom theme, you will have to declare theme in themes.xml file, and set styles in styles.xml file.

Time calculation in php (add 10 hours)?

In order to increase or decrease time using strtotime you could use a Relative format in the first argument.

In your case to increase the current time by 10 hours:

$date = date('h:i:s A', strtotime('+10 hours'));

In case you need to apply the change to another timestamp, the second argument can be specified.

Note:

Using this function for mathematical operations is not advisable. It is better to use DateTime::add() and DateTime::sub() in PHP 5.3 and later, or DateTime::modify() in PHP 5.2.

So, the recommended way since PHP 5.3:

$dt = new DateTime(); // assuming we need to add to the current time
$dt->add(new DateInterval('PT10H'));
$date = $dt->format('h:i:s A');

or using aliases:

$dt = date_create(); // assuming we need to add to the current time
date_add($dt, date_interval_create_from_date_string('10 hours')); 
$date = date_format($dt, 'h:i:s A');

In all cases the default time zone will be used unless a time zone is specified.

Model summary in pytorch

AFAK there is no model.summary() like equivalent in pytorch

Meanwhile you can refer script by szagoruyko, which gives a nice visualizaton like in resnet18-example

Cheers

Moment.js - how do I get the number of years since a date, not rounded up?

This method works for me. It's checking if the person has had their birthday this year and subtracts one year otherwise.

// date is the moment you're calculating the age of
var now = moment().unix();
var then = date.unix();
var diff = (now - then) / (60 * 60 * 24 * 365);
var years = Math.floor(diff);

Edit: First version didn't quite work perfectly. The updated one should

What is the difference between Amazon SNS and Amazon SQS?

SNS is a distributed publish-subscribe system. Messages are pushed to subscribers as and when they are sent by publishers to SNS.

SQS is distributed queuing system. Messages are not pushed to receivers. Receivers have to poll or pull messages from SQS. Messages can't be received by multiple receivers at the same time. Any one receiver can receive a message, process and delete it. Other receivers do not receive the same message later. Polling inherently introduces some latency in message delivery in SQS unlike SNS where messages are immediately pushed to subscribers. SNS supports several end points such as email, SMS, HTTP end point and SQS. If you want unknown number and type of subscribers to receive messages, you need SNS.

You don't have to couple SNS and SQS always. You can have SNS send messages to email, SMS or HTTP end point apart from SQS. There are advantages to coupling SNS with SQS. You may not want an external service to make connections to your hosts (a firewall may block all incoming connections to your host from outside).

Your end point may just die because of heavy volume of messages. Email and SMS maybe not your choice of processing messages quickly. By coupling SNS with SQS, you can receive messages at your pace. It allows clients to be offline, tolerant to network and host failures. You also achieve guaranteed delivery. If you configure SNS to send messages to an HTTP end point or email or SMS, several failures to send message may result in messages being dropped.

SQS is mainly used to decouple applications or integrate applications. Messages can be stored in SQS for a short duration of time (maximum 14 days). SNS distributes several copies of messages to several subscribers. For example, let’s say you want to replicate data generated by an application to several storage systems. You could use SNS and send this data to multiple subscribers, each replicating the messages it receives to different storage systems (S3, hard disk on your host, database, etc.).

jQuery counting elements by class - what is the best way to implement this?

HTML:

<div>
    <img src='' class='class' />
    <img src='' class='class' />
    <img src='' class='class' />
</div>

    

JavaScript:

var numItems = $('.class').length; 
        
alert(numItems);

Fiddle demo for inside only div

Using ExcelDataReader to read Excel data starting from a particular cell

Very easy with ExcelReaderFactory 3.1 and up:

using (var openFileDialog1 = new OpenFileDialog { Filter = "Excel Workbook|*.xls;*.xlsx;*.xlsm", ValidateNames = true })
{
    if (openFileDialog1.ShowDialog() == DialogResult.OK)
    {
        var fs = File.Open(openFileDialog1.FileName, FileMode.Open, FileAccess.Read);
        var reader = ExcelReaderFactory.CreateBinaryReader(fs);
        var dataSet = reader.AsDataSet(new ExcelDataSetConfiguration
        {
            ConfigureDataTable = _ => new ExcelDataTableConfiguration
            {
                UseHeaderRow = true // Use first row is ColumnName here :D
            }
        });
        if (dataSet.Tables.Count > 0)
        {
            var dtData = dataSet.Tables[0];
            // Do Something
        }
    }
}

All combinations of a list of lists

from itertools import product 
list_vals = [['Brand Acronym:CBIQ', 'Brand Acronym :KMEFIC'],['Brand Country:DXB','Brand Country:BH']]
list(product(*list_vals))

Output:

[('Brand Acronym:CBIQ', 'Brand Country :DXB'),
('Brand Acronym:CBIQ', 'Brand Country:BH'),
('Brand Acronym :KMEFIC', 'Brand Country :DXB'),
('Brand Acronym :KMEFIC', 'Brand Country:BH')]

how to release localhost from Error: listen EADDRINUSE

ps -ef |grep node find app.js , kill pid of app.js

What is the JavaScript version of sleep()?

If you're on node.js, you can have a look at fibers – a native C extension to node, a kinda-multi-threading simulation.

It allows you to do a real sleep in a way which is blocking execution in a fiber, but it's non-blocking in the main thread and other fibers.

Here's an example fresh from their own readme:

// sleep.js

var Fiber = require('fibers');

function sleep(ms) {
    var fiber = Fiber.current;
    setTimeout(function() {
        fiber.run();
    }, ms);
    Fiber.yield();
}

Fiber(function() {
    console.log('wait... ' + new Date);
    sleep(1000);
    console.log('ok... ' + new Date);
}).run();
console.log('back in main');

– and the results are:

$ node sleep.js
wait... Fri Jan 21 2011 22:42:04 GMT+0900 (JST)
back in main
ok... Fri Jan 21 2011 22:42:05 GMT+0900 (JST)

How do I get ruby to print a full backtrace instead of a truncated one?

This produces the error description and nice clean, indented stacktrace:

begin               
 # Some exception throwing code
rescue => e
  puts "Error during processing: #{$!}"
  puts "Backtrace:\n\t#{e.backtrace.join("\n\t")}"
end

Removing trailing newline character from fgets() input

I'm a bit surprised that no one has mentioned this. In general, rather than trimming data that you don't want, avoid writing it in the first place. If you don't want the newline in the buffer, don't use fgets. Instead, use getc or fgetc or scanf. Perhaps something like:

#include <stdio.h>
#include <stdlib.h>
int
main(void)
{
        char Name[256];
        char fmt[32];
        int rc;
        sprintf(fmt, "%%%zd[^\n]", sizeof Name - 1);
        if( (rc = scanf(fmt, Name)) == 1 ) {
                printf("Name = %s\n", Name);
        }
        return rc == 1 ? EXIT_SUCCESS : EXIT_FAILURE;
}

"SyntaxError: Unexpected token < in JSON at position 0"

In a nutshell, if you're getting this error or similar error, that means only one thing. That is, in someplace in our codebase we were expecting a valid JSON format to process and we didn't get one. For example:

var string = "some string";
JSON.parse(string)

Will throw an error, saying

Uncaught SyntaxError: Unexpected token s in JSON at position 0

Because, the first character in string is s & it's not a valid JSON now. This can throw error in between also. like:

var invalidJSON= '{"foo" : "bar", "missedquotehere : "value" }';
JSON.parse(invalidJSON)

Will throw error:

VM598:1 Uncaught SyntaxError: Unexpected token v in JSON at position 36

because we intentionally missed a quote in the JSON string invalidJSON at position 36.

And if you fix that:

var validJSON= '{"foo" : "bar", "missedquotehere : "value" }';
JSON.parse(validJSON)

will give you an object in JSON.

Now, this error can be thrown in any place & in any framework/library. Most of the time you may be reading a network response which is not valid JSON. So steps of debugging this issue can be like:

  1. curl or hit the actual API you're calling.
  2. Log/Copy the response and try to parse it with JSON.parse. If you're getting error, fix it.
  3. If not, make sure your code is not mutating/changing the original response.

Is HTML considered a programming language?

I think that it definitely has its place on a resume. Knowledge of HTML is valuable, and there really is a lot to know, what with cross-browser compatibility issues and standards which should be followed.

I wouldn't list HTML under "programming languages" alongside C# or something, but it's worth noting your experience.

How do you get the contextPath from JavaScript, the right way?

Reviewer the solution by this Checking the solution of this page, make the following solution I hope it works: Example:

Javascript:

var context = window.location.pathname.substring(0, window.location.pathname.indexOf("/",2)); 
var url =window.location.protocol+"//"+ window.location.host +context+"/bla/bla";

console.log(result) returns [object Object]. How do I get result.name?

Try adding JSON.stringify(result) to convert the JS Object into a JSON string.

From your code I can see you are logging the result in error which is called if the AJAX request fails, so I'm not sure how you'd go about accessing the id/name/etc. then (you are checking for success inside the error condition!).

Note that if you use Chrome's console you should be able to browse through the object without having to stringify the JSON, which makes it easier to debug.

Replace only text inside a div using jquery

Text shouldn't be on its own. Put it into a span element.

Change it to this:

<div id="one">
       <div class="first"></div>
       <span>"Hi I am text"</span>
       <div class="second"></div>
       <div class="third"></div>
</div>
$('#one span').text('Hi I am replace');

Validation failed for one or more entities while saving changes to SQL Server Database using Entity Framework

I have faced same issue a couple of days ago while updating the database. In my case, there was few new non nullable columns added for maintenance which was not supplied in the code which is causing the exception. I figure out those fields and supplied values for them and its resolved.

Print a file, skipping the first X lines, in Bash

This shell script works fine for me:

#!/bin/bash
awk -v initial_line=$1 -v end_line=$2 '{
    if (NR >= initial_line && NR <= end_line) 
    print $0
}' $3

Used with this sample file (file.txt):

one
two
three
four
five
six

The command (it will extract from second to fourth line in the file):

edu@debian5:~$./script.sh 2 4 file.txt

Output of this command:

two
three
four

Of course, you can improve it, for example by testing that all argument values are the expected :-)

Installation failed with message Invalid File

Please follow the below steps File > Settings > Build,Execution,Deployment > Instant Run > Un-check (Enable Instant Run to hot swap code)

this is working for me

thanks

SQL join: selecting the last records in a one-to-many relationship

Without getting into the code first, the logic/algorithm goes below:

  1. Go to the transaction table with multiple records for the same client.

  2. Select records of clientID and the latestDate of client's activity using group by clientID and max(transactionDate)

       select clientID, max(transactionDate) as latestDate 
       from transaction 
       group by clientID
    
  3. inner join the transaction table with the outcome from Step 2, then you will have the full records of the transaction table with only each client's latest record.

       select * from 
       transaction t 
       inner join (
         select clientID, max(transactionDate) as latestDate
         from transaction 
         group by clientID) d 
       on t.clientID = d.clientID and t.transactionDate = d.latestDate) 
    
  4. You can use the result from step 3 to join any table you want to get different results.

Getting Django admin url for an object

Here's another option, using models:

Create a base model (or just add the admin_link method to a particular model)

class CommonModel(models.Model):
    def admin_link(self):
        if self.pk:
            return mark_safe(u'<a target="_blank" href="../../../%s/%s/%s/">%s</a>' % (self._meta.app_label,
                    self._meta.object_name.lower(), self.pk, self))
        else:
            return mark_safe(u'')
    class Meta:
        abstract = True

Inherit from that base model

   class User(CommonModel):
        username = models.CharField(max_length=765)
        password = models.CharField(max_length=192)

Use it in a template

{{ user.admin_link }}

Or view

user.admin_link()

Unsupported Media Type in postman

Http 415 Media Unsupported is responded back only when the content type header you are providing is not supported by the application.

With POSTMAN, the Content-type header you are sending is Content type 'multipart/form-data not application/json. While in the ajax code you are setting it correctly to application/json. Pass the correct Content-type header in POSTMAN and it will work.

sed: print only matching group

grep is the right tool for extracting.

using your example and your regex:

kent$  echo 'foo bar <foo> bla 1 2 3.4'|grep -o '[0-9][0-9]*[\ \t][0-9.]*[\ \t]*$'
2 3.4

SQL Server stored procedure Nullable parameter

It looks like you're passing in Null for every argument except for PropertyValueID and DropDownOptionID, right? I don't think any of your IF statements will fire if only these two values are not-null. In short, I think you have a logic error.

Other than that, I would suggest two things...

First, instead of testing for NULL, use this kind syntax on your if statements (it's safer)...

    ELSE IF ISNULL(@UnitValue, 0) != 0 AND ISNULL(@UnitOfMeasureID, 0) = 0

Second, add a meaningful PRINT statement before each UPDATE. That way, when you run the sproc in MSSQL, you can look at the messages and see how far it's actually getting.

Get client IP address via third party web service

If you face an issue of CORS, you can use https://api.ipify.org/.

function httpGet(theUrl)
{
    var xmlHttp = new XMLHttpRequest();
    xmlHttp.open( "GET", theUrl, false );
    xmlHttp.send( null );
    return xmlHttp.responseText;
}


publicIp = httpGet("https://api.ipify.org/");
alert("Public IP: " + publicIp);

I agree that using synchronous HTTP call is not good idea. You can use async ajax call then.

How to get folder directory from HTML input type "file" or any other way?

Stumbled on this page as well, and then found out this is possible with just javascript (no plugins like ActiveX or Flash), but just in chrome:

https://plus.google.com/+AddyOsmani/posts/Dk5UhZ6zfF3

Basically, they added support for a new attribute on the file input element "webkitdirectory". You can use it like this:

<input type="file" id="ctrl" webkitdirectory directory multiple/>

It allows you to select directories. The multiple attribute is a good fallback for browsers that support multiple file selection but not directory selection.

When you select a directory the files are available through the dom object for the control (document.getElementById('ctrl')), just like they are with the multiple attribute. The browsers adds all files in the selected directory to that list recursively.

You can already add the directory attribute as well in case this gets standardized at some point (couldn't find any info regarding that)

Adding line break in C# Code behind page

guys.. use resources for long strings in code behind!!

also.. you don't need an _ for codeline breaks in C#. In VB the codelines end with a newline character (or a ':'), using the the _ would tell the parser it has not reached the end of the line yet. The codeline in C# ends with a ';' so you can use newlines to styleformat your code.

How to get margin value of a div in plain JavaScript?

I found something very useful on this site when I was searching for an answer on this question. You can check it out at http://www.codingforums.com/javascript-programming/230503-how-get-margin-left-value.html. The part that helped me was the following:

_x000D_
_x000D_
/***
 * get live runtime value of an element's css style
 *   http://robertnyman.com/2006/04/24/get-the-rendered-style-of-an-element
 *     note: "styleName" is in CSS form (i.e. 'font-size', not 'fontSize').
 ***/
var getStyle = function(e, styleName) {
  var styleValue = "";
  if (document.defaultView && document.defaultView.getComputedStyle) {
    styleValue = document.defaultView.getComputedStyle(e, "").getPropertyValue(styleName);
  } else if (e.currentStyle) {
    styleName = styleName.replace(/\-(\w)/g, function(strMatch, p1) {
      return p1.toUpperCase();
    });
    styleValue = e.currentStyle[styleName];
  }
  return styleValue;
}
////////////////////////////////////
var e = document.getElementById('yourElement');
var marLeft = getStyle(e, 'margin-left');
console.log(marLeft);    // 10px
_x000D_
#yourElement {
  margin-left: 10px;
}
_x000D_
<div id="yourElement"></div>
_x000D_
_x000D_
_x000D_

Undefined index error PHP

There should be the problem, when you generate the <form>. I bet the variables $name, $price are NULL or empty string when you echo them into the value of the <input> field. Empty input fields are not sent by the browser, so $_POST will not have their keys.

Anyway, you can check that with isset().

Test variables with the following:

if(isset($_POST['key'])) ? $variable=$_POST['key'] : $variable=NULL

You better set it to NULL, because

NULL value represents a variable with no value.

Detecting Back Button/Hash Change in URL

Use the jQuery hashchange event plugin instead. Regarding your full ajax navigation, try to have SEO friendly ajax. Otherwise your pages shown nothing in browsers with JavaScript limitations.

setting system property

You can do this via a couple ways.

One is when you run your application, you can pass it a flag.

java -Dgate.home="http://gate.ac.uk/wiki/code-repository" your_application

Or set it programmatically in code before the piece of code that needs this property set. Java keeps a Properties object for System wide configuration.

Properties props = System.getProperties();
props.setProperty("gate.home", "http://gate.ac.uk/wiki/code-repository");

Change the jquery show()/hide() animation?

Use slidedown():

$("test").slideDown("slow");

How to provide shadow to Button

For android version 5.0 & above

try the Elevation for other views..

android:elevation="10dp"

For Buttons,

android:stateListAnimator="@anim/button_state_list_animator"

button_state_list_animator.xml - https://android.googlesource.com/platform/frameworks/base/+/master/core/res/res/anim/button_state_list_anim_material.xml

below 5.0 version,

For all views,

 android:background="@android:drawable/dialog_holo_light_frame"

My output:

enter image description here

Basic Authentication Using JavaScript

Today we use Bearer token more often that Basic Authentication but if you want to have Basic Authentication first to get Bearer token then there is a couple ways:

const request = new XMLHttpRequest();
request.open('GET', url, false, username,password)
request.onreadystatechange = function() {
        // D some business logics here if you receive return
   if(request.readyState === 4 && request.status === 200) {
       console.log(request.responseText);
   }
}
request.send()

Full syntax is here

Second Approach using Ajax:

$.ajax
({
  type: "GET",
  url: "abc.xyz",
  dataType: 'json',
  async: false,
  username: "username",
  password: "password",
  data: '{ "key":"sample" }',
  success: function (){
    alert('Thanks for your up vote!');
  }
});

Hopefully, this provides you a hint where to start API calls with JS. In Frameworks like Angular, React, etc there are more powerful ways to make API call with Basic Authentication or Oauth Authentication. Just explore it.

Creating a very simple linked list

Dmytro did a good job, but here is a more concise version.

class Program
{
    static void Main(string[] args)
    {
        LinkedList linkedList = new LinkedList(1);

        linkedList.Add(2);
        linkedList.Add(3);
        linkedList.Add(4);

        linkedList.AddFirst(0);

        linkedList.Print();            
    }
}

public class Node
{
    public Node(Node next, Object value)
    {
        this.next = next;
        this.value = value;
    }

    public Node next;
    public Object value;
}

public class LinkedList
{
    public Node head;

    public LinkedList(Object initial)
    {
        head = new Node(null, initial);
    }

    public void AddFirst(Object value)
    {
        head = new Node(head, value);            
    }

    public void Add(Object value)
    {
        Node current = head;

        while (current.next != null)
        {
            current = current.next;
        }

        current.next = new Node(null, value);
    }

    public void Print()
    {
        Node current = head;

        while (current != null)
        {
            Console.WriteLine(current.value);
            current = current.next;
        }
    }
}

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

Differences between isinstance() and type() in Python?

Type-checking with

isinstance(obj, Base)

allows for instances of subclasses and multiple possible bases:

isinstance(obj, (Base1, Base2))

whereas type-checking with

type(obj) is Base

only supports the type referenced.


As a sidenote, is is likely more appropriate than

type(obj) == Base

because classes are singletons.

Avoid type-checking - use Polymorphism (duck-typing)

In Python, usually you want to allow any type for your arguments, treat it as expected, and if the object doesn't behave as expected, it will raise an appropriate error. This is known as polymorphism, also known as duck-typing.

def function_of_duck(duck):
    duck.quack()
    duck.swim()

If the code above works, we can presume our argument is a duck. Thus we can pass in other things are actual sub-types of duck:

function_of_duck(mallard)

or that work like a duck:

function_of_duck(object_that_quacks_and_swims_like_a_duck)

and our code still works.

However, there are some cases where it is desirable to explicitly type-check. Perhaps you have sensible things to do with different object types. For example, the Pandas Dataframe object can be constructed from dicts or records. In such a case, your code needs to know what type of argument it is getting so that it can properly handle it.

So, to answer the question:

Differences between isinstance() and type() in Python?

Allow me to demonstrate the difference:

type

Say you need to ensure a certain behavior if your function gets a certain kind of argument (a common use-case for constructors). If you check for type like this:

def foo(data):
    '''accepts a dict to construct something, string support in future'''
    if type(data) is not dict:
        # we're only going to test for dicts for now
        raise ValueError('only dicts are supported for now')

If we try to pass in a dict that is a subclass of dict (as we should be able to, if we're expecting our code to follow the principle of Liskov Substitution, that subtypes can be substituted for types) our code breaks!:

from collections import OrderedDict

foo(OrderedDict([('foo', 'bar'), ('fizz', 'buzz')]))

raises an error!

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in foo
ValueError: argument must be a dict

isinstance

But if we use isinstance, we can support Liskov Substitution!:

def foo(a_dict):
    if not isinstance(a_dict, dict):
        raise ValueError('argument must be a dict')
    return a_dict

foo(OrderedDict([('foo', 'bar'), ('fizz', 'buzz')]))

returns OrderedDict([('foo', 'bar'), ('fizz', 'buzz')])

Abstract Base Classes

In fact, we can do even better. collections provides Abstract Base Classes that enforce minimal protocols for various types. In our case, if we only expect the Mapping protocol, we can do the following, and our code becomes even more flexible:

from collections import Mapping

def foo(a_dict):
    if not isinstance(a_dict, Mapping):
        raise ValueError('argument must be a dict')
    return a_dict

Response to comment:

It should be noted that type can be used to check against multiple classes using type(obj) in (A, B, C)

Yes, you can test for equality of types, but instead of the above, use the multiple bases for control flow, unless you are specifically only allowing those types:

isinstance(obj, (A, B, C))

The difference, again, is that isinstance supports subclasses that can be substituted for the parent without otherwise breaking the program, a property known as Liskov substitution.

Even better, though, invert your dependencies and don't check for specific types at all.

Conclusion

So since we want to support substituting subclasses, in most cases, we want to avoid type-checking with type and prefer type-checking with isinstance - unless you really need to know the precise class of an instance.

Export data from R to Excel

writexl, without Java requirement:

# install.packages("writexl")
library(writexl)
tempfile <- write_xlsx(iris)

How to give color to each class in scatter plot in R?

One way is to use the lattice package and xyplot():

R> DF <- data.frame(x=1:10, y=rnorm(10)+5, 
+>                  z=sample(letters[1:3], 10, replace=TRUE))
R> DF
    x       y z
1   1 3.91191 c
2   2 4.57506 a
3   3 3.16771 b
4   4 5.37539 c
5   5 4.99113 c
6   6 5.41421 a
7   7 6.68071 b
8   8 5.58991 c
9   9 5.03851 a
10 10 4.59293 b
R> with(DF, xyplot(y ~ x, group=z))

By giving explicit grouping information via variable z, you obtain different colors. You can specify colors etc, see the lattice documentation.

Because z here is a factor variable for which we obtain the levels (== numeric indices), you can also do

R> with(DF, plot(x, y, col=z))

but that is less transparent (to me, at least :) then xyplot() et al.

Python: Is there an equivalent of mid, right, and left from BASIC?

This is Andy's solution. I just addressed User2357112's concern and gave it meaningful variable names. I'm a Python rookie and preferred these functions.

def left(aString, howMany):
    if howMany <1:
        return ''
    else:
        return aString[:howMany]

def right(aString, howMany):
    if howMany <1:
        return ''
    else:
        return aString[-howMany:]

def mid(aString, startChar, howMany):
    if howMany < 1:
        return ''
    else:
        return aString[startChar:startChar+howMany]

HTML5 live streaming

You can use a fantastic library name Videojs. You will find more useful informations here. But with quick start you can do something like this:

<link href="//vjs.zencdn.net/5.11/video-js.min.css" rel="stylesheet">
<script src="//vjs.zencdn.net/5.11/video.min.js"></script>
<video 
id="Video" 
class="video-js vjs-default-skin vjs-big-play-centered" 
controls 
preload="none" 
width="auto" 
height="auto" 
poster="poster.jpg" 
data-setup='{"techOrder": ["flash", "html5", "other supported tech"], "nativeControlsForTouch": true, "controlBar": { "muteToggle": false, "volumeControl": false, "timeDivider": false, "durationDisplay": false, "progressControl": false } }'
>
<source src="rtmp://{domain_server}/{publisher}" type='rtmp/mp4'/>
</video>
<script>
var player = videojs('Video');
player.play();
</script>

How to determine the version of android SDK installed in computer?

Type in android list target into your command line to see what android API you are using.

How to read a large file line by line?

I would strongly recommend not using the default file loading as it is horrendously slow. You should look into the numpy functions and the IOpro functions (e.g. numpy.loadtxt()).

http://docs.scipy.org/doc/numpy/user/basics.io.genfromtxt.html

https://store.continuum.io/cshop/iopro/

Then you can break your pairwise operation into chunks:

import numpy as np
import math

lines_total = n    
similarity = np.zeros(n,n)
lines_per_chunk = m
n_chunks = math.ceil(float(n)/m)
for i in xrange(n_chunks):
    for j in xrange(n_chunks):
        chunk_i = (function of your choice to read lines i*lines_per_chunk to (i+1)*lines_per_chunk)
        chunk_j = (function of your choice to read lines j*lines_per_chunk to (j+1)*lines_per_chunk)
        similarity[i*lines_per_chunk:(i+1)*lines_per_chunk,
                   j*lines_per_chunk:(j+1)*lines_per_chunk] = fast_operation(chunk_i, chunk_j) 

It's almost always much faster to load data in chunks and then do matrix operations on it than to do it element by element!!

Failed to allocate memory: 8

Works with 512 Mb instead. None of the above methods works for me.

VBA code to show Message Box popup if the formula in the target cell exceeds a certain value

I don't think a message box is the best way to go with this as you would need the VB code running in a loop to check the cell contents, or unless you plan to run the macro manually. In this case I think it would be better to add conditional formatting to the cell to change the background to red (for example) if the value exceeds the upper limit.

Javascript Uncaught Reference error Function is not defined

If you are using Angular.js then functions imbedded into HTML, such as onclick="function()" or onchange="function()". They will not register. You need to make the change events in the javascript. Such as:

$('#exampleBtn').click(function() {
  function();
});

Best way to encode text data for XML in Java?

If you are looking for a library to get the job done, try:

  1. Guava 26.0 documented here

    return XmlEscapers.xmlContentEscaper().escape(text);

    Note: There is also an xmlAttributeEscaper()

  2. Apache Commons Text 1.4 documented here

    StringEscapeUtils.escapeXml11(text)

    Note: There is also an escapeXml10() method

PHP get domain name

Similar question has been asked in stackoverflow before.

See here: PHP $_SERVER['HTTP_HOST'] vs. $_SERVER['SERVER_NAME'], am I understanding the man pages correctly?

Also see this article: http://shiflett.org/blog/2006/mar/server-name-versus-http-host

Recommended using HTTP_HOST, and falling back on SERVER_NAME only if HTTP_HOST was not set. He said that SERVER_NAME could be unreliable on the server for a variety of reasons, including:

  • no DNS support
  • misconfigured
  • behind load balancing software

Source: http://discussion.dreamhost.com/thread-4388.html

Importing data from a JSON file into R

First install the RJSONIO and RCurl package:

_x000D_
_x000D_
install.packages("RJSONIO")_x000D_
install.packages("(RCurl")
_x000D_
_x000D_
_x000D_

Try below code using RJSONIO in console

_x000D_
_x000D_
library(RJSONIO)_x000D_
library(RCurl)_x000D_
json_file = getURL("https://raw.githubusercontent.com/isrini/SI_IS607/master/books.json")_x000D_
json_file2 = RJSONIO::fromJSON(json_file)_x000D_
head(json_file2)
_x000D_
_x000D_
_x000D_

json_encode is returning NULL?

For anyone using PDO, the solution is similar to ntd's answer.

From the PHP PDO::__construct page, as a comment from the user Kiipa at live dot com:

To get UTF-8 charset you can specify that in the DSN.

$link = new PDO("mysql:host=localhost;dbname=DB;charset=UTF8");

Using routes in Express-js

No one should ever have to keep writing app.use('/someRoute', require('someFile')) until it forms a heap of code.

It just doesn't make sense at all to be spending time invoking/defining routings. Even if you do need custom control, it's probably only for some of the time, and for the most bit you want to be able to just create a standard file structure of routings and have a module do it automatically.

Try Route Magic

As you scale your app, the routing invocations will start to form a giant heap of code that serves no purpose. You want to do just 2 lines of code to handle all the app.use routing invocations with Route Magic like this:

const magic = require('express-routemagic')
magic.use(app, __dirname, '[your route directory]')

For those you want to handle manually, just don't use pass the directory to Magic.

The backend version is not supported to design database diagrams or tables

I ran into this problem when SQL Server 2014 standard was installed on a server where SQL Server Express was also installed. I had opened SSMS from a desktop shortcut, not realizing right away that it was SSMS for SQL Server Express, not for 2014. SSMS for Express returned the error, but SQL Server 2014 did not.

What is the best way to conditionally apply a class?

We can make a function to manage return class with condition

enter image description here

<script>
    angular.module('myapp', [])
            .controller('ExampleController', ['$scope', function ($scope) {
                $scope.MyColors = ['It is Red', 'It is Yellow', 'It is Blue', 'It is Green', 'It is Gray'];
                $scope.getClass = function (strValue) {
                    switch(strValue) {
                        case "It is Red":return "Red";break;
                        case "It is Yellow":return "Yellow";break;
                        case "It is Blue":return "Blue";break;
                        case "It is Green":return "Green";break;
                        case "It is Gray":return "Gray";break;
                    }
                }
        }]);
</script>

And then

<body ng-app="myapp" ng-controller="ExampleController">

<h2>AngularJS ng-class if example</h2>
<ul >
    <li ng-repeat="icolor in MyColors" >
        <p ng-class="[getClass(icolor), 'b']">{{icolor}}</p>
    </li>
</ul>
<hr/>
<p>Other way using : ng-class="{'class1' : expression1, 'class2' : expression2,'class3':expression2,...}"</p>
<ul>
    <li ng-repeat="icolor in MyColors">
        <p ng-class="{'Red':icolor=='It is Red','Yellow':icolor=='It is Yellow','Blue':icolor=='It is Blue','Green':icolor=='It is Green','Gray':icolor=='It is Gray'}" class="b">{{icolor}}</p>
    </li>
</ul>

You can refer to full code page at ng-class if example

undefined reference to WinMain@16 (codeblocks)

Well I know this answer is not an experienced programmer's approach and of an Old It consultant , but it worked for me .

the answer is "TRY TURNING IT ON AND OFF" . restart codeblocks and it works well reminds me of the 2006 comedy show It Crowd .

coercing to Unicode: need string or buffer, NoneType found when rendering in django admin

In my case it was something else: the object I was saving should first have an id(e.g. save() should be called) before I could set any kind of relationship with it.

Trust Store vs Key Store - creating with keytool

Keystore is used by a server to store private keys, and Truststore is used by third party client to store public keys provided by server to access. I have done that in my production application. Below are the steps for generating java certificates for SSL communication:

  1. Generate a certificate using keygen command in windows:

keytool -genkey -keystore server.keystore -alias mycert -keyalg RSA -keysize 2048 -validity 3950

  1. Self certify the certificate:

keytool -selfcert -alias mycert -keystore server.keystore -validity 3950

  1. Export certificate to folder:

keytool -export -alias mycert -keystore server.keystore -rfc -file mycert.cer

  1. Import Certificate into client Truststore:

keytool -importcert -alias mycert -file mycert.cer -keystore truststore

How to remove the default arrow icon from a dropdown list (select element)?

There's no need for hacks or overflow. There's a pseudo-element for the dropdown arrow on IE:

select::-ms-expand {
    display: none;
}

What is the proper way to check and uncheck a checkbox in HTML5?

<input type="checkbox" checked />

HTML5 does not require attributes to have values

Bootstrap 3 .col-xs-offset-* doesn't work?

A suggestion for when you want to do an offset but find yourself incapable at extra small widths:

Use .hidden-xs and .visible-xs to make one version of your html block for extra small widths, and one for everything else (where you can still use an offset)

Example:

<div class="hero container">
  <div class="row">
    <div class="hidden-xs col-sm-8 col-sm-offset-2 col-md-4 col-md-offset-4 text-center">
      <h2>This is a banner at the top of my site. It shows in everything except XS</h2>
      <p>Here are some supporting details about my banner.</p>
    </div>
    <div class="visible-xs col-xs-12">
      <h2 class="pull-right">This is my banner at XS width.</h2>
      <p class="pull-right">This is my supporting content at XS width.</p>
    </div>
  </div>
</div>

The OLE DB provider "Microsoft.ACE.OLEDB.12.0" for linked server "(null)"

In our case, it helped to add a parameter for SQL Server service:

  1. Go to Services.msc, select SQL Server Service and open Properties.
  2. Choose Startup Parameters and add new parameter –g512
  3. Restart SQL server service.

Remote debugging a Java application

Answer covering Java >= 9:

For Java 9+, the JVM option needs a slight change by prefixing the address with the IP address of the machine hosting the JVM, or just *:

-agentlib:jdwp=transport=dt_socket,server=y,address=*:8000,suspend=n

This is due to a change noted in https://www.oracle.com/technetwork/java/javase/9-notes-3745703.html#JDK-8041435.

For Java < 9, the port number is enough to connect.

run main class of Maven project

Try the maven-exec-plugin. From there:

mvn exec:java -Dexec.mainClass="com.example.Main"

This will run your class in the JVM. You can use -Dexec.args="arg0 arg1" to pass arguments.

If you're on Windows, apply quotes for exec.mainClass and exec.args:

mvn exec:java -D"exec.mainClass"="com.example.Main"

If you're doing this regularly, you can add the parameters into the pom.xml as well:

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <version>1.2.1</version>
  <executions>
    <execution>
      <goals>
        <goal>java</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <mainClass>com.example.Main</mainClass>
    <arguments>
      <argument>foo</argument>
      <argument>bar</argument>
    </arguments>
  </configuration>
</plugin>

How to get temporary folder for current user

try

Environment.GetEnvironmentVariable("temp");

Radio/checkbox alignment in HTML/CSS

This is a bit of a hack but this CSS seems to get it working very nicely in all browsers the same as using tables (apart from chrome)

input[type=radio] { vertical-align: middle; margin: 0; *margin-top: -2px; }
label { vertical-align: middle; }
@media screen and (-webkit-min-device-pixel-ratio:0) {
 input[type=radio] { margin-top: -2px; }
}

Make sure you use labels with your radios for it to work. i.e.

<option> <label>My Radio</label>

Split code over multiple lines in an R script

I know this post is old, but I had a Situation like this and just want to share my solution. All the answers above work fine. But if you have a Code such as those in data.table chaining Syntax it becomes abit challenging. e.g. I had a Problem like this.

mass <- files[, Veg:=tstrsplit(files$file, "/")[1:4][[1]]][, Rain:=tstrsplit(files$file, "/")[1:4][[2]]][, Roughness:=tstrsplit(files$file, "/")[1:4][[3]]][, Geom:=tstrsplit(files$file, "/")[1:4][[4]]][time_[s]<=12000]

I tried most of the suggestions above and they didn´t work. but I figured out that they can be split after the comma within []. Splitting at ][ doesn´t work.

mass <- files[, Veg:=tstrsplit(files$file, "/")[1:4][[1]]][, 
    Rain:=tstrsplit(files$file, "/")[1:4][[2]]][, 
    Roughness:=tstrsplit(files$file, "/")[1:4][[3]]][, 
    Geom:=tstrsplit(files$file, "/")[1:4][[4]]][`time_[s]`<=12000]

How to vertically align label and input in Bootstrap 3?

The bootstrap 3 docs for horizontal forms let you use the .form-horizontal class to make your form labels and inputs vertically aligned. The structure for these forms is:

<form class="form-horizontal" role="form">
  <div class="form-group">
    <label for="input1" class="col-lg-2 control-label">Label1</label>
    <div class="col-lg-10">
      <input type="text" class="form-control" id="input1" placeholder="Input1">
    </div>
  </div>
  <div class="form-group">
    <label for="input2" class="col-lg-2 control-label">Label2</label>
    <div class="col-lg-10">
      <input type="password" class="form-control" id="input2" placeholder="Input2">
    </div>
  </div>
</form>

Therefore, your form should look like this:

<form class="form-horizontal" role="form">
    <div class="form-group">
        <div class="col-xs-3">
            <label for="class_type"><h2><span class=" label label-primary">Class Type</span></h2></label>
        </div>
        <div class="col-xs-2">
            <select id="class_type" class="form-control input-lg" autocomplete="off">
                <option>Economy</option>
                <option>Premium Economy</option>
                <option>Club World</option>
                <option>First Class</option>
            </select>
        </div>
    </div>
</form>

How do you reverse a string in place in JavaScript?

Seems like I'm 3 years late to the party...

Unfortunately you can't as has been pointed out. See Are JavaScript strings immutable? Do I need a "string builder" in JavaScript?

The next best thing you can do is to create a "view" or "wrapper", which takes a string and reimplements whatever parts of the string API you are using, but pretending the string is reversed. For example:

var identity = function(x){return x};

function LazyString(s) {
    this.original = s;

    this.length = s.length;
    this.start = 0; this.stop = this.length; this.dir = 1; // "virtual" slicing
    // (dir=-1 if reversed)

    this._caseTransform = identity;
}

// syntactic sugar to create new object:
function S(s) {
    return new LazyString(s);
}

//We now implement a `"...".reversed` which toggles a flag which will change our math:

(function(){ // begin anonymous scope
    var x = LazyString.prototype;

    // Addition to the String API
    x.reversed = function() {
        var s = new LazyString(this.original);

        s.start = this.stop - this.dir;
        s.stop = this.start - this.dir;
        s.dir = -1*this.dir;
        s.length = this.length;

        s._caseTransform = this._caseTransform;
        return s;
    }

//We also override string coercion for some extra versatility (not really necessary):

    // OVERRIDE STRING COERCION
    //   - for string concatenation e.g. "abc"+reversed("abc")
    x.toString = function() {
        if (typeof this._realized == 'undefined') {  // cached, to avoid recalculation
            this._realized = this.dir==1 ?
                this.original.slice(this.start,this.stop) : 
                this.original.slice(this.stop+1,this.start+1).split("").reverse().join("");

            this._realized = this._caseTransform.call(this._realized, this._realized);
        }
        return this._realized;
    }

//Now we reimplement the String API by doing some math:

    // String API:

    // Do some math to figure out which character we really want

    x.charAt = function(i) {
        return this.slice(i, i+1).toString();
    }
    x.charCodeAt = function(i) {
        return this.slice(i, i+1).toString().charCodeAt(0);
    }

// Slicing functions:

    x.slice = function(start,stop) {
        // lazy chaining version of https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/slice

        if (stop===undefined)
            stop = this.length;

        var relativeStart = start<0 ? this.length+start : start;
        var relativeStop = stop<0 ? this.length+stop : stop;

        if (relativeStart >= this.length)
            relativeStart = this.length;
        if (relativeStart < 0)
            relativeStart = 0;

        if (relativeStop > this.length)
            relativeStop = this.length;
        if (relativeStop < 0)
            relativeStop = 0;

        if (relativeStop < relativeStart)
            relativeStop = relativeStart;

        var s = new LazyString(this.original);
        s.length = relativeStop - relativeStart;
        s.start = this.start + this.dir*relativeStart;
        s.stop = s.start + this.dir*s.length;
        s.dir = this.dir;

        //console.log([this.start,this.stop,this.dir,this.length], [s.start,s.stop,s.dir,s.length])

        s._caseTransform = this._caseTransform;
        return s;
    }
    x.substring = function() {
        // ...
    }
    x.substr = function() {
        // ...
    }

//Miscellaneous functions:

    // Iterative search

    x.indexOf = function(value) {
        for(var i=0; i<this.length; i++)
            if (value==this.charAt(i))
                return i;
        return -1;
    }
    x.lastIndexOf = function() {
        for(var i=this.length-1; i>=0; i--)
            if (value==this.charAt(i))
                return i;
        return -1;
    }

    // The following functions are too complicated to reimplement easily.
    // Instead just realize the slice and do it the usual non-in-place way.

    x.match = function() {
        var s = this.toString();
        return s.apply(s, arguments);
    }
    x.replace = function() {
        var s = this.toString();
        return s.apply(s, arguments);
    }
    x.search = function() {
        var s = this.toString();
        return s.apply(s, arguments);
    }
    x.split = function() {
        var s = this.toString();
        return s.apply(s, arguments);
    }

// Case transforms:

    x.toLowerCase = function() {
        var s = new LazyString(this.original);
        s._caseTransform = ''.toLowerCase;

        s.start=this.start; s.stop=this.stop; s.dir=this.dir; s.length=this.length;

        return s;
    }
    x.toUpperCase = function() {
        var s = new LazyString(this.original);
        s._caseTransform = ''.toUpperCase;

        s.start=this.start; s.stop=this.stop; s.dir=this.dir; s.length=this.length;

        return s;
    }

})() // end anonymous scope

Demo:

> r = S('abcABC')
LazyString
  original: "abcABC"
  __proto__: LazyString

> r.charAt(1);       // doesn't reverse string!!! (good if very long)
"B"

> r.toLowerCase()    // must reverse string, so does so
"cbacba"

> r.toUpperCase()    // string already reversed: no extra work
"CBACBA"

> r + '-demo-' + r   // natural coercion, string already reversed: no extra work
"CBAcba-demo-CBAcba"

The kicker -- the following is done in-place by pure math, visiting each character only once, and only if necessary:

> 'demo: ' + S('0123456789abcdef').slice(3).reversed().slice(1,-1).toUpperCase()
"demo: EDCBA987654"

> S('0123456789ABCDEF').slice(3).reversed().slice(1,-1).toLowerCase().charAt(3)
"b"

This yields significant savings if applied to a very large string, if you are only taking a relatively small slice thereof.

Whether this is worth it (over reversing-as-a-copy like in most programming languages) highly depends on your use case and how efficiently you reimplement the string API. For example if all you want is to do string index manipulation, or take small slices or substrs, this will save you space and time. If you're planning on printing large reversed slices or substrings however, the savings may be small indeed, even worse than having done a full copy. Your "reversed" string will also not have the type string, though you might be able to fake this with prototyping.

The above demo implementation creates a new object of type ReversedString. It is prototyped, and therefore fairly efficient, with almost minimal work and minimal space overhead (prototype definitions are shared). It is a lazy implementation involving deferred slicing. Whenever you perform a function like .slice or .reversed, it will perform index mathematics. Finally when you extract data (by implicitly calling .toString() or .charCodeAt(...) or something), it will apply those in a "smart" manner, touching the least data possible.

Note: the above string API is an example, and may not be implemented perfectly. You also can use just 1-2 functions which you need.

Python: how to capture image from webcam on click using OpenCV

This is a simple program to capture an image from using a default camera. Also, It can Detect a human face.

import cv2
import sys
import logging as log
import datetime as dt
from time import sleep

cascPath = "haarcascade_frontalface_default.xml"
faceCascade = cv2.CascadeClassifier(cascPath)
log.basicConfig(filename='webcam.log',level=log.INFO)

video_capture = cv2.VideoCapture(0)
anterior = 0

while True:
    if not video_capture.isOpened():
        print('Unable to load camera.')
        sleep(5)
        pass

    # Capture frame-by-frame
    ret, frame = video_capture.read()

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    faces = faceCascade.detectMultiScale(
        gray,
        scaleFactor=1.1,
        minNeighbors=5,
        minSize=(30, 30)
    )

    # Draw a rectangle around the faces
    for (x, y, w, h) in faces:
        cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 255, 0), 2)

    if anterior != len(faces):
        anterior = len(faces)
        log.info("faces: "+str(len(faces))+" at "+str(dt.datetime.now()))


    # Display the resulting frame
    cv2.imshow('Video', frame)

    if cv2.waitKey(1) & 0xFF == ord('s'): 

        check, frame = video_capture.read()
        cv2.imshow("Capturing", frame)
        cv2.imwrite(filename='saved_img.jpg', img=frame)
        video_capture.release()
        img_new = cv2.imread('saved_img.jpg', cv2.IMREAD_GRAYSCALE)
        img_new = cv2.imshow("Captured Image", img_new)
        cv2.waitKey(1650)
        print("Image Saved")
        print("Program End")
        cv2.destroyAllWindows()

        break
    elif cv2.waitKey(1) & 0xFF == ord('q'):
        print("Turning off camera.")
        video_capture.release()
        print("Camera off.")
        print("Program ended.")
        cv2.destroyAllWindows()
        break

    # Display the resulting frame
    cv2.imshow('Video', frame)

# When everything is done, release the capture
video_capture.release()
cv2.destroyAllWindows()

output

enter image description here

Also, You can check out my GitHub code

What do 1.#INF00, -1.#IND00 and -1.#IND mean?

For those of you in a .NET environment the following can be a handy way to filter non-numbers out (this example is in VB.NET, but it's probably similar in C#):

If Double.IsNaN(MyVariableName) Then
    MyVariableName = 0 ' Or whatever you want to do here to "correct" the situation
End If

If you try to use a variable that has a NaN value you will get the following error:

Value was either too large or too small for a Decimal.

How can I get all a form's values that would be submitted without submitting

Thanks Chris. That's what I was looking for. However, note that the method is serialize(). And there is another method serializeArray() that looks very useful that I may use. Thanks for pointing me in the right direction.

var queryString = $('#frmAdvancedSearch').serialize();
alert(queryString);

var fieldValuePairs = $('#frmAdvancedSearch').serializeArray();
$.each(fieldValuePairs, function(index, fieldValuePair) {
    alert("Item " + index + " is [" + fieldValuePair.name + "," + fieldValuePair.value + "]");
});

Unpacking a list / tuple of pairs into two lists / tuples

list1 = (x[0] for x in source_list)
list2 = (x[1] for x in source_list)

How to update fields in a model without creating a new record in django?

Sometimes it may be required to execute the update atomically that is using one update request to the database without reading it first.

Also get-set attribute-save may cause problems if such updates may be done concurrently or if you need to set the new value based on the old field value.

In such cases query expressions together with update may by useful:

TemperatureData.objects.filter(id=1).update(value=F('value') + 1)

python: urllib2 how to send cookie with urlopen request

This answer is not working since the urllib2 module has been split across several modules in Python 3. You need to do

from urllib import request
opener = request.build_opener()
opener.addheaders.append(('Cookie', 'cookiename=cookievalue'))
f = opener.open("http://example.com/")

Removing items from a ListBox in VB.net

There is a simple method for deleting selected items, and all these people are going for a hard method:

lstYOURVARIABLE.Items.Remove(lstYOURVARIABLE.SelectedItem)

I used this in Visual Basic mode on Visual Studio.

Microsoft.ReportViewer.Common Version=12.0.0.0

here the link to webreports version 12 https://www.nuget.org/packages/Microsoft.ReportViewer.WebForms.v12/12.0.0?_src=template

after the package installed

on your toolbox browse the dll reference it to bin then that's it run the visual studio

Add a CSS class to <%= f.submit %>

Rails 4 and Bootstrap 3 "primary" button

<%= f.submit nil, :class => 'btn btn-primary' %>

Yields something like:

screen-2014-01-22_02.24.26.png

How do I get interactive plots again in Spyder/IPython/matplotlib?

You can quickly control this by typing built-in magic commands in Spyder's IPython console, which I find faster than picking these from the preferences menu. Changes take immediate effect, without needing to restart Spyder or the kernel.

To switch to "automatic" (i.e. interactive) plots, type:

%matplotlib auto

then if you want to switch back to "inline", type this:

%matplotlib inline

(Note: these commands don't work in non-IPython consoles)

See more background on this topic: Purpose of "%matplotlib inline"

In Tkinter is there any way to make a widget not visible?

I'm also extremely late to the party, but I'll leave my version of the answer here for others who may have gotten here, like I did, searching for how to hide something that was placed on the screen with the .place() function, and not .pack() neither .grid().

In short, you can hide a widget by setting the width and height to zero, like this:

widget.place(anchor="nw", x=0, y=0, width=0, height=0)

To give a bit of context so you can see what my requirement was and how I got here. In my program, I have a window that needs to display several things that I've organized into 2 frames, something like this:

[WINDOW - app]
  [FRAME 1 - hMainWndFrame]
    [Buttons and other controls (widgets)]
  [FRAME 2 - hJTensWndFrame]
    [other Buttons and controls (widgets)]

Only one frame needs to be visible at a time, so on application initialisation, i have something like this:

hMainWndFrame = Frame(app, bg="#aababd")
hMainWndFrame.place(anchor="nw", x=0, y=0, width=480, height=320)
...
hJTensWndFrame = Frame(app, bg="#aababd")

I'm using .place() instead of .pack() or .grid() because i specifically want to set precise coordinates on the window for each widget. So, when i want to hide the main frame and display the other one (along with all the other controls), all i have to do is call the .place() function again, on each frame, but specifying zero for width and height for the one i want to hide and the necessary width and height for the one i want to show, such as:

hMainWndFrame.place(anchor="nw", x=0, y=0, width=0, height=0)
hJTensWndFrame.place(anchor="nw", x=0, y=0, width=480, height=320)

Now it's true, I only tested this on Frames, not on other widgets, but I guess it should work on everything.

How to use awk sort by column 3

awk -F, '{ print $3, $0 }' user.csv | sort -nk2 

and for reverse order

awk -F, '{ print $3, $0 }' user.csv | sort -nrk2 

How to let an ASMX file output JSON

Are you calling the web service from client script or on the server side?

You may find sending a content type header to the server will help, e.g.

'application/json; charset=utf-8'

On the client side, I use prototype client side library and there is a contentType parameter when making an Ajax call where you can specify this. I think jQuery has a getJSON method.

Use a loop to plot n charts Python

Use a dictionary!!

You can also use dictionaries that allows you to have more control over the plots:

import matplotlib.pyplot as plt
#   plot 0     plot 1    plot 2   plot 3
x=[[1,2,3,4],[1,4,3,4],[1,2,3,4],[9,8,7,4]]
y=[[3,2,3,4],[3,6,3,4],[6,7,8,9],[3,2,2,4]]

plots = zip(x,y)
def loop_plot(plots):
    figs={}
    axs={}
    for idx,plot in enumerate(plots):
        figs[idx]=plt.figure()
        axs[idx]=figs[idx].add_subplot(111)
        axs[idx].plot(plot[0],plot[1])
return figs, axs

figs, axs = loop_plot(plots)

Now you can select the plot that you want to modify easily:

axs[0].set_title("Now I can control it!")

Of course, is up to you to decide what to do with the plots. You can either save them to disk figs[idx].savefig("plot_%s.png" %idx) or show them plt.show(). Use the argument block=False only if you want to pop up all the plots together (this could be quite messy if you have a lot of plots). You can do this inside the loop_plot function or in a separate loop using the dictionaries that the function provided.

PowerShell: Create Local User Account

As of 2014, here is a statement from a Microsoft representative (the Scripting Guy):

As much as we might hate to admit it, there are still no Windows PowerShell cmdlets from Microsoft that permit creating local user accounts or local user groups. We finally have a Desired State Configuration (DSC ) provider that can do this—but to date, no cmdlets.

How do I create my own URL protocol? (e.g. so://...)

It's called the protocol. The only thing that prevents you from making your own protocol is you have to:

  1. Write a browser or user agent of some kinds that understands that protocol, both in its URL form and in the actual data format
  2. Write a server that understands that protocol
  3. Preferably, have a specification for the protocol so that browser and server can continue to work together.

Windows makes #1 really easy, an in many cases this is all you actually need. Viz:

Registering an Application to a URL Protocol

How to get the type of a variable in MATLAB?

Use the class function

>> b = 2
b =
     2
>> a = 'Hi'
a =
Hi
>> class(b)
ans =
double
>> class(a)
ans =
char

Error: Cannot access file bin/Debug/... because it is being used by another process

Ugh, this is an old problem, something that still pops up in Visual Studio once in a while. It's bitten me a couple of times and I've lost hours restarting and fighting with VS. I'm sure it's been discussed here on SO more than once. It's also been talked about on the MSDN forums. There isn't an actual solution, but there are a couple of workarounds. Start researching here.

What's happening is that VS is acquiring a lock on a file and then not releasing it. Ironically, that lock prevents VS itself from deleting the file so that it can recreate it when you rebuild the application. The only apparent solution is to close and restart VS so that it will release the lock on the file.

My original workaround was opening up the bin/Debug folder and renaming the executable. You can't delete it if it's locked, but you can rename it. So you can just add a number to the end or something, which allows you to keep working without having to close all of your windows and wait for VS to restart. Some people have even automated this using a pre-build event to append a random string to the end of the old output filename. Yes, this is a giant hack, but this problem gets so frustrating and debilitating that you'll do anything.

I've later learned, after a bit more experimentation, that the problem seems to only crop up when you build the project with one of the designers open. So, the solution that has worked for me long term and prevented me from ever dealing with one of those silly errors again is making sure that I always close all designer windows before building a WinForms project. Yes, this too is somewhat inconvenient, but it sure beats the pants off having to restart VS twice an hour or more.

I assume this applies to WPF, too, although I don't use it and haven't personally experienced the problem there.

I also haven't yet tried reproducing it on VS 2012 RC. I don't know if it's been fixed there yet or not. But my experience so far has been that it still manages to pop up even after Microsoft has claimed to have fixed it. It's still there in VS 2010 SP1. I'm not saying their programmers are idiots who don't know what they're doing, of course. I figure there are just multiple causes for the bug and/or that it's very difficult to reproduce reliably in a laboratory. That's the same reason I haven't personally filed any bug reports on it (although I've +1'ed other peoples), because I can't seem to reliably reproduce it, rather like the Abominable Snowman.

<end rant that is directed at no one in particular>

How can I get the length of text entered in a textbox using jQuery?

var myLength = $("#myTextbox").val().length;

Finding all objects that have a given property inside a collection

A very common problem and I have used google collections and here is my code

public class FindByIdPredicate implements Predicate<IDObject> {

private Long entityId;

public FindByIdPredicate(final Long entityId) {
    this.entityId = entityId;

}

@Override
public boolean apply(final IDObject input) {
    return input.getId().equals(this.entityId);
}

/**
     * Pass in the Collection
 * @param Collection
 * @return IdObject if present or null
 */
public IDObject getEntity(final Collection<? extends IDObject> collection) {

    for (IDObject idObject : collection) {
        if (this.apply(idObject)) {
            return idObject;
        }
    }
    return null;

}

/**
 * @param Set
 * @return IdObject if present or null
 */
@SuppressWarnings("unchecked")
public <T> T getEntity(final Set<? extends IDObject> set) {

    for (IDObject idObject : set) {
        if (this.apply(idObject)) {
            return (T) idObject;
        }
    }
    return null;

}

}

Hope this helps

Parse query string in JavaScript

How about this?

function getQueryVar(varName){
    // Grab and unescape the query string - appending an '&' keeps the RegExp simple
    // for the sake of this example.
    var queryStr = unescape(window.location.search) + '&';

    // Dynamic replacement RegExp
    var regex = new RegExp('.*?[&\\?]' + varName + '=(.*?)&.*');

    // Apply RegExp to the query string
    var val = queryStr.replace(regex, "$1");

    // If the string is the same, we didn't find a match - return false
    return val == queryStr ? false : val;
}

..then just call it with:

alert('Var "dest" = ' + getQueryVar('dest'));

Cheers

Difference between no-cache and must-revalidate

max-age=0, must-revalidate and no-cache aren't exactly identical. With must-revalidate, if the server doesn't respond to a revalidation request, the browser/proxy is supposed to return a 504 error. With no-cache, it would just show the cached content, which would be probably preferred by the user (better to have something stale than nothing at all). This is why must-revalidate is intended for critical transactions only.

Entity framework code-first null foreign key

I have the same problem now , I have foreign key and i need put it as nullable, to solve this problem you should put

    modelBuilder.Entity<Country>()
        .HasMany(c => c.Users)
        .WithOptional(c => c.Country)
        .HasForeignKey(c => c.CountryId)
        .WillCascadeOnDelete(false);

in DBContext class I am sorry for answer you very late :)

How many bits or bytes are there in a character?

There are 8 bits in a byte (normally speaking in Windows).

However, if you are dealing with characters, it will depend on the charset/encoding. Unicode character can be 2 or 4 bytes, so that would be 16 or 32 bits, whereas Windows-1252 sometimes incorrectly called ANSI is only 1 bytes so 8 bits.

In Asian version of Windows and some others, the entire system runs in double-byte, so a character is 16 bits.

EDITED

Per Matteo's comment, all contemporary versions of Windows use 16-bits internally per character.

commons httpclient - Adding query string parameters to GET/POST request

I am using httpclient 4.4.

For solr query I used the following way and it worked.

NameValuePair nv2 = new BasicNameValuePair("fq","(active:true) AND (category:Fruit OR category1:Vegetable)");
nvPairList.add(nv2);
NameValuePair nv3 = new BasicNameValuePair("wt","json");
nvPairList.add(nv3);
NameValuePair nv4 = new BasicNameValuePair("start","0");
nvPairList.add(nv4);
NameValuePair nv5 = new BasicNameValuePair("rows","10");
nvPairList.add(nv5);

HttpClient client = HttpClientBuilder.create().build();
HttpGet request = new HttpGet(url);
URI uri = new URIBuilder(request.getURI()).addParameters(nvPairList).build();
            request.setURI(uri);

HttpResponse response = client.execute(request);    
if (response.getStatusLine().getStatusCode() != 200) {

}

BufferedReader br = new BufferedReader(
                             new InputStreamReader((response.getEntity().getContent())));

String output;
System.out.println("Output  .... ");
String respStr = "";
while ((output = br.readLine()) != null) {
    respStr = respStr + output;
    System.out.println(output);
}

Display all dataframe columns in a Jupyter Python Notebook

Python 3.x for large (but not too large) DataFrames

Maybe because I have an older version of pandas but on Jupyter notebook this work for me

import pandas as pd
from IPython.core.display import HTML

df=pd.read_pickle('Data1')
display(HTML(df.to_html()))

How to use select/option/NgFor on an array of objects in Angular2

I don't know what things were like in the alpha, but I'm using beta 12 right now and this works fine. If you have an array of objects, create a select like this:

<select [(ngModel)]="simpleValue"> // value is a string or number
    <option *ngFor="let obj of objArray" [value]="obj.value">{{obj.name}}</option>
</select>

If you want to match on the actual object, I'd do it like this:

<select [(ngModel)]="objValue"> // value is an object
    <option *ngFor="let obj of objArray" [ngValue]="obj">{{obj.name}}</option>
</select>

How can apply multiple background color to one div

Sorry for misunderstanding, from what I understood you want your DIV to have three different colors with different heights. This is the output of my code:

output,

If this is what you want try this code:

_x000D_
_x000D_
div {_x000D_
    height: 100px;_x000D_
    width:400px;_x000D_
    position: relative;_x000D_
}_x000D_
.c {_x000D_
    background: blue; /* Old browsers */_x000D_
}_x000D_
_x000D_
.c:after{_x000D_
    content: '';_x000D_
    position: absolute;_x000D_
    width:20%;_x000D_
    left:0;_x000D_
    height:110%;_x000D_
    background: yellow;_x000D_
}_x000D_
.c:before{_x000D_
    content: '';_x000D_
    position: absolute;_x000D_
    width:40%;_x000D_
    left:60%;_x000D_
    height:140%;_x000D_
    background: green;_x000D_
}
_x000D_
<div class="c"></div>
_x000D_
_x000D_
_x000D_

The container 'Maven Dependencies' references non existing library - STS

So I get you are using Eclipse with the M2E plugin. Try to update your Maven configuration : In the Project Explorer, right-click on the project, Maven -> Update project.

If the problem still remains, try to clean your project: right-click on your pom.xml, Run as -> Maven build (the second one). Enter "clean package" in the Goals fields. Check the Skip Tests box. Click on the Run button.

Edit: For your new problem, you need to add Spring MVC to your pom.xml. Add something like the following:

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>4.0.0.RELEASE</version>
</dependency>

Maybe you have to change the version to match the version of your Spring framework. Take a look here:

http://mvnrepository.com/artifact/org.springframework/spring-webmvc

XML element with attribute and content using JAXB

Here is working solution:

Output:

public class XmlTest {

    private static final Logger log = LoggerFactory.getLogger(XmlTest.class);

    @Test
    public void createDefaultBook() throws JAXBException {
        JAXBContext jaxbContext = JAXBContext.newInstance(Book.class);
        Marshaller marshaller = jaxbContext.createMarshaller();

        StringWriter writer = new StringWriter();
        marshaller.marshal(new Book(), writer);

        log.debug("Book xml:\n {}", writer.toString());
    }


    @XmlAccessorType(XmlAccessType.FIELD)
    @XmlRootElement(name = "book")
    public static class Book {

        @XmlElementRef(name = "price")
        private Price price = new Price();


    }

    @XmlAccessorType(XmlAccessType.FIELD)
    @XmlRootElement(name = "price")
    public static class Price {
        @XmlAttribute(name = "drawable")
        private Boolean drawable = true; //you may want to set default value here

        @XmlValue
        private int priceValue = 1234;

        public Boolean getDrawable() {
            return drawable;
        }

        public void setDrawable(Boolean drawable) {
            this.drawable = drawable;
        }

        public int getPriceValue() {
            return priceValue;
        }

        public void setPriceValue(int priceValue) {
            this.priceValue = priceValue;
        }
    }
}

Output:

22:00:18.471 [main] DEBUG com.grebski.stack.XmlTest - Book xml:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<book>
    <price drawable="true">1234</price>
</book>

How to set an button align-right with Bootstrap?

<div class="container">
    <div class="btn-block pull-right">
        <a href="#" class="btn btn-primary pull-right">Search</a>
        <a href="#" class="btn btn-primary pull-right">Apple</a>
        <a href="#" class="btn btn-primary pull-right">Sony</a>
    </div>
</div>

jQuery ajax success callback function definition

after few hours play with it and nearly become dull. miracle came to me, it work.

<pre>


var listname = [];   


 $.ajax({
    url : wedding, // change to your local url, this not work with absolute url
    success: function (data) {
       callback(data);
    }
});

function callback(data) {
      $(data).find("a").attr("href", function (i, val) {
            if( val.match(/\.(jpe?g|png|gif)$/) ) { 
             //   $('#displayImage1').append( "<img src='" + wedding + val +"'>" );
                 listname.push(val);
            } 
        });
}

function myfunction() {

alert (listname);

}

</pre>

c - warning: implicit declaration of function ‘printf’

the warning or error of kind IMPLICIT DECLARATION is that the compiler is expecting a Function Declaration/Prototype..

It might either be a header file or your own function Declaration..

Differences between arm64 and aarch64

AArch64 is the 64-bit state introduced in the Armv8-A architecture (https://en.wikipedia.org/wiki/ARM_architecture#ARMv8-A). The 32-bit state which is backwards compatible with Armv7-A and previous 32-bit Arm architectures is referred to as AArch32. Therefore the GNU triplet for the 64-bit ISA is aarch64. The Linux kernel community chose to call their port of the kernel to this architecture arm64 rather than aarch64, so that's where some of the arm64 usage comes from.

As far as I know the Apple backend for aarch64 was called arm64 whereas the LLVM community-developed backend was called aarch64 (as it is the canonical name for the 64-bit ISA) and later the two were merged and the backend now is called aarch64.

So AArch64 and ARM64 refer to the same thing.

Android Studio emulator does not come with Play Store for API 23

Solved in easy way: You should create a new emulator, before opening it for the first time follow these 3 easy steps:

1- go to "C:\Users[user].android\avd[your virtual device folder]" open "config.ini" with text editor like notepad

2- change

"PlayStore.enabled=false" to "PlayStore.enabled=true"

3- change

"mage.sysdir.1 = system-images\android-30\google_apis\x86"

to

"image.sysdir.1 = system-images\android-30\google_apis_playstore\x86"

How to change background Opacity when bootstrap modal is open

you can set the opacity by the last parameter of rgb function.

the opacity is 0.5 in the example

.modal-backdrop {
    background-color: rgb(0, 0, 0, 0.5);
}

Sort objects in ArrayList by date?

Given MyObject that has a DateTime member with a getDateTime() method, you can sort an ArrayList that contains MyObject elements by the DateTime objects like this:

Collections.sort(myList, new Comparator<MyObject>() {
    public int compare(MyObject o1, MyObject o2) {
        return o1.getDateTime().lt(o2.getDateTime()) ? -1 : 1;
    }
});

Python ValueError: too many values to unpack

for k, m in self.materials.items():

example:

miles_dict = {'Monday':1, 'Tuesday':2.3, 'Wednesday':3.5, 'Thursday':0.9}
for k, v in miles_dict.items():
    print("%s: %s" % (k, v))

Get the ID of a drawable in ImageView

I recently run into the same problem. I solved it by implementing my own ImageView class.

Here is my Kotlin implementation:

class MyImageView(context: Context): ImageView(context) {
    private var currentDrawableId: Int? = null

    override fun setImageResource(resId: Int) {
        super.setImageResource(resId)
        currentDrawableId = resId
    }

    fun getDrawableId() {
        return currentDrawableId
    }

    fun compareCurrentDrawable(toDrawableId: Int?): Boolean {
        if (toDrawableId == null || currentDrawableId != toDrawableId) {
            return false
        }

        return true
    }

}

How to use placeholder as default value in select2 framework

Try this.In html you write the following code.

<select class="select2" multiple="multiple" placeholder="Select State">
    <option value="AK">Alaska</option>
    <option value="HI">Hawaii</option>
</select>

And in your script write the below code.Keep in mind that have the link of select2js.

<script>
         $( ".select2" ).select2( { } );
 </script>

Mvn install or Mvn package

mvn install is the option that is most often used.
mvn package is seldom used, only if you're debugging some issue with the maven build process.

See: http://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html

Note that mvn package will only create a jar file.
mvn install will do that and install the jar (and class etc.) files in the proper places if other code depends on those jars.

I usually do a mvn clean install; this deletes the target directory and recreates all jars in that location.
The clean helps with unneeded or removed stuff that can sometimes get in the way.
Rather then debug (some of the time) just start fresh all of the time.

How to create a new file in unix?

Try > workdirectory/filename.txt

This would:

  • truncate the file if it exists
  • create if it doesn't exist

You can consider it equivalent to:

rm -f workdirectory/filename.txt; touch workdirectory/filename.txt

Check if Internet Connection Exists with jQuery?

I wrote a jQuery plugin for doing this. By default it checks the current URL (because that's already loaded once from the Web) or you can specify a URL to use as an argument. Always doing a request to Google isn't the best idea because it's blocked in different countries at different times. Also you might be at the mercy of what the connection across a particular ocean/weather front/political climate might be like that day.

http://tomriley.net/blog/archives/111

Convert data.frame column format from character to factor

# To do it for all names
df[] <- lapply( df, factor) # the "[]" keeps the dataframe structure
 col_names <- names(df)
# to do it for some names in a vector named 'col_names'
df[col_names] <- lapply(df[col_names] , factor)

Explanation. All dataframes are lists and the results of [ used with multiple valued arguments are likewise lists, so looping over lists is the task of lapply. The above assignment will create a set of lists that the function data.frame.[<- should successfully stick back into into the dataframe, df

Another strategy would be to convert only those columns where the number of unique items is less than some criterion, let's say fewer than the log of the number of rows as an example:

cols.to.factor <- sapply( df, function(col) length(unique(col)) < log10(length(col)) )
df[ cols.to.factor] <- lapply(df[ cols.to.factor] , factor)

What's the difference between "Solutions Architect" and "Applications Architect"?

No, an architect has a different job than a programmer. The architect is more concerned with nonfunctional ("ility") requirements. Like reliability, maintainability, security, and so on. (If you don't agree, consider this thought experiment: compare a CGI program written in C that does a complicated website, versus a Ruby on Rails implementation. They both have the same functional behavior; choosing an RoR architecture has what advantages.)

Generally, a "solution architect" is about the whole system -- hardware, software, and all -- which an "application architect" is working within a fixed platform, but the terms aren't that rigorous or well standardized.

What’s the best way to load a JSONObject from a json text file?

try this:

import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;
import org.apache.commons.io.IOUtils; 

    public class JsonParsing {

        public static void main(String[] args) throws Exception {
            InputStream is = 
                    JsonParsing.class.getResourceAsStream( "sample-json.txt");
            String jsonTxt = IOUtils.toString( is );

            JSONObject json = (JSONObject) JSONSerializer.toJSON( jsonTxt );        
            double coolness = json.getDouble( "coolness" );
            int altitude = json.getInt( "altitude" );
            JSONObject pilot = json.getJSONObject("pilot");
            String firstName = pilot.getString("firstName");
            String lastName = pilot.getString("lastName");

            System.out.println( "Coolness: " + coolness );
            System.out.println( "Altitude: " + altitude );
            System.out.println( "Pilot: " + lastName );
        }
    }

and this is your sample-json.txt , should be in json format

{
 'foo':'bar',
 'coolness':2.0,
 'altitude':39000,
 'pilot':
     {
         'firstName':'Buzz',
         'lastName':'Aldrin'
     },
 'mission':'apollo 11'
}

Using form input to access camera and immediately upload photos using web app

It's really easy to do this, simply send the file via an XHR request inside of the file input's onchange handler.

<input id="myFileInput" type="file" accept="image/*;capture=camera">

var myInput = document.getElementById('myFileInput');

function sendPic() {
    var file = myInput.files[0];

    // Send file here either by adding it to a `FormData` object 
    // and sending that via XHR, or by simply passing the file into 
    // the `send` method of an XHR instance.
}

myInput.addEventListener('change', sendPic, false);

How to view the list of compile errors in IntelliJ?

You should disable Power Save Mode

For me I clicked over this button

enter image description here

then disable Power Save Mode

CSS endless rotation animation

Infinite rotation animation in CSS

_x000D_
_x000D_
/* ENDLESS ROTATE */_x000D_
.rotate{_x000D_
  animation: rotate 1.5s linear infinite; _x000D_
}_x000D_
@keyframes rotate{_x000D_
  to{ transform: rotate(360deg); }_x000D_
}_x000D_
_x000D_
_x000D_
/* SPINNER JUST FOR DEMO */_x000D_
.spinner{_x000D_
  display:inline-block; width: 50px; height: 50px;_x000D_
  border-radius: 50%;_x000D_
  box-shadow: inset -2px 0 0 2px #0bf;_x000D_
}
_x000D_
<span class="spinner rotate"></span>
_x000D_
_x000D_
_x000D_

MDN - Web CSS Animation

css3 transition animation on load?

Not really, as CSS is applied as soon as possible, but the elements might not be drawn yet. You could guess a delay of 1 or 2 seconds, but this won't look right for most people, depending on the speed of their internet.

In addition, if you want to fade something in for instance, it would require CSS that hides the content to be delivered. If the user doesn't have CSS3 transitions then they would never see it.

I'd recommend using jQuery (for ease of use + you may wish to add animation for other UAs) and some JS like this:

$(document).ready(function() {
    $('#id_to_fade_in')
        .css({"opacity":0})   // Set to 0 as soon as possible – may result in flicker, but it's not hidden for users with no JS (Googlebot for instance!)
        .delay(200)           // Wait for a bit so the user notices it fade in
        .css({"opacity":1});  // Fade it back in. Swap css for animate in legacy browsers if required.
});

Along with the transitions added in the CSS. This has the advantage of easily allowing the use of animate instead of the second CSS in legacy browsers if required.

Tree implementation in Java (root, parents and children)

Since @Jonathan's answer still consisted of some bugs, I made an improved version. I overwrote the toString() method for debugging purposes, be sure to change it accordingly to your data.

import java.util.ArrayList;
import java.util.List;

/**
 * Provides an easy way to create a parent-->child tree while preserving their depth/history.
 * Original Author: Jonathan, https://stackoverflow.com/a/22419453/14720622
 */
public class TreeNode<T> {
    private final List<TreeNode<T>> children;
    private TreeNode<T> parent;
    private T data;
    private int depth;

    public TreeNode(T data) {
        // a fresh node, without a parent reference
        this.children = new ArrayList<>();
        this.parent = null;
        this.data = data;
        this.depth = 0; // 0 is the base level (only the root should be on there)
    }

    public TreeNode(T data, TreeNode<T> parent) {
        // new node with a given parent
        this.children = new ArrayList<>();
        this.data = data;
        this.parent = parent;
        this.depth = (parent.getDepth() + 1);
        parent.addChild(this);
    }

    public int getDepth() {
        return this.depth;
    }

    public void setDepth(int depth) {
        this.depth = depth;
    }

    public List<TreeNode<T>> getChildren() {
        return children;
    }

    public void setParent(TreeNode<T> parent) {
        this.setDepth(parent.getDepth() + 1);
        parent.addChild(this);
        this.parent = parent;
    }

    public TreeNode<T> getParent() {
        return this.parent;
    }

    public void addChild(T data) {
        TreeNode<T> child = new TreeNode<>(data);
        this.children.add(child);
    }

    public void addChild(TreeNode<T> child) {
        this.children.add(child);
    }

    public T getData() {
        return this.data;
    }

    public void setData(T data) {
        this.data = data;
    }

    public boolean isRootNode() {
        return (this.parent == null);
    }

    public boolean isLeafNode() {
        return (this.children.size() == 0);
    }

    public void removeParent() {
        this.parent = null;
    }

    @Override
    public String toString() {
        String out = "";
        out += "Node: " + this.getData().toString() + " | Depth: " + this.depth + " | Parent: " + (this.getParent() == null ? "None" : this.parent.getData().toString()) + " | Children: " + (this.getChildren().size() == 0 ? "None" : "");
        for(TreeNode<T> child : this.getChildren()) {
            out += "\n\t" + child.getData().toString() + " | Parent: " + (child.getParent() == null ? "None" : child.getParent().getData());
        }
        return out;
    }
}

And for the visualization:

import model.TreeNode;

/**
 * Entrypoint
 */
public class Main {
    public static void main(String[] args) {
        TreeNode<String> rootNode = new TreeNode<>("Root");
        TreeNode<String> firstNode = new TreeNode<>("Child 1 (under Root)", rootNode);
        TreeNode<String> secondNode = new TreeNode<>("Child 2 (under Root)", rootNode);
        TreeNode<String> thirdNode = new TreeNode<>("Child 3 (under Child 2)", secondNode);
        TreeNode<String> fourthNode = new TreeNode<>("Child 4 (under Child 3)", thirdNode);
        TreeNode<String> fifthNode = new TreeNode<>("Child 5 (under Root, but with a later call)");
        fifthNode.setParent(rootNode);

        System.out.println(rootNode.toString());
        System.out.println(firstNode.toString());
        System.out.println(secondNode.toString());
        System.out.println(thirdNode.toString());
        System.out.println(fourthNode.toString());
        System.out.println(fifthNode.toString());
        System.out.println("Is rootNode a root node? - " + rootNode.isRootNode());
        System.out.println("Is firstNode a root node? - " + firstNode.isRootNode());
        System.out.println("Is thirdNode a leaf node? - " + thirdNode.isLeafNode());
        System.out.println("Is fifthNode a leaf node? - " + fifthNode.isLeafNode());
    }
}

Example output:

Node: Root | Depth: 0 | Parent: None | Children: 
    Child 1 (under Root) | Parent: Root
    Child 2 (under Root) | Parent: Root
    Child 5 (under Root, but with a later call) | Parent: Root
Node: Child 1 (under Root) | Depth: 1 | Parent: Root | Children: None
Node: Child 2 (under Root) | Depth: 1 | Parent: Root | Children: 
    Child 3 (under Child 2) | Parent: Child 2 (under Root)
Node: Child 3 (under Child 2) | Depth: 2 | Parent: Child 2 (under Root) | Children: 
    Child 4 (under Child 3) | Parent: Child 3 (under Child 2)
Node: Child 4 (under Child 3) | Depth: 3 | Parent: Child 3 (under Child 2) | Children: None
Node: Child 5 (under Root, but with a later call) | Depth: 1 | Parent: Root | Children: None
Is rootNode a root node? - true
Is firstNode a root node? - false
Is thirdNode a leaf node? - false
Is fifthNode a leaf node? - true

Some additional informations: Do not use addChildren() and setParent() together. You'll end up having two references as setParent() already updates the children=>parent relationship.

How to solve npm error "npm ERR! code ELIFECYCLE"

I've been bothered by this issue for a long time. For me, the version of node was the problem.

My npm and node were 6.1.0 and 8.11.3, respectively. However, I didn't realize that I had updated my node accidentally to 12.*.*.

It then began to install GCX stuff whenever npm i, which was unnecessary before.

I downgraded my node to 8 and it worked!

Streaming video from Android camera to server

I am able to send the live camera video from mobile to my server.using this link see the link

Refer the above link.there is a sample application in that link. Just you need to set your service url in RecordActivity.class.

Example as: ffmpeg_link="rtmp://yourserveripaddress:1935/live/venkat";

we can able to send H263 and H264 type videos using that link.

How to pass an array within a query string?

Here's what I figured out:

Submitting multi-value form fields, i.e. submitting arrays through GET/POST vars, can be done several different ways, as a standard is not necessarily spelled out.

Three possible ways to send multi-value fields or arrays would be:

  • ?cars[]=Saab&cars[]=Audi (Best way- PHP reads this into an array)
  • ?cars=Saab&cars=Audi (Bad way- PHP will only register last value)
  • ?cars=Saab,Audi (Haven't tried this)

Form Examples

On a form, multi-valued fields could take the form of a select box set to multiple:

<form> 
    <select multiple="multiple" name="cars[]"> 
        <option>Volvo</option> 
        <option>Saab</option> 
        <option>Mercedes</option> 
    </select>
</form>

(NOTE: In this case, it would be important to name the select control some_name[], so that the resulting request vars would be registered as an array by PHP)

... or as multiple hidden fields with the same name:

<input type="hidden" name="cars[]" value="Volvo">
<input type="hidden" name="cars[]" value="Saab">
<input type="hidden" name="cars[]" value="Mercedes">

NOTE: Using field[] for multiple values is really poorly documented. I don't see any mention of it in the section on multi-valued keys in Query string - Wikipedia, or in the W3C docs dealing with multi-select inputs.


UPDATE

As commenters have pointed out, this is very much framework-specific. Some examples:

Query string:

?list_a=1&list_a=2&list_a=3&list_b[]=1&list_b[]=2&list_b[]=3&list_c=1,2,3

Rails:

"list_a": "3", 
"list_b":[
    "1",
    "2",
    "3"
  ], 
"list_c": "1,2,3"

Angular:

 "list_a": [
    "1",
    "2",
    "3"
  ],
  "list_b[]": [
    "1",
    "2",
    "3"
  ],
  "list_c": "1,2,3"

(Angular discussion)

See comments for examples in node.js, Wordpress, ASP.net


Maintaining order: One more thing to consider is that if you need to maintain the order of your items (i.e. array as an ordered list), you really only have one option, which is passing a delimited list of values, and explicitly converting it to an array yourself.

Django - filtering on foreign key properties

This has been possible since the queryset-refactor branch landed pre-1.0. Ticket 4088 exposed the problem. This should work:

Asset.objects.filter(
    desc__contains=filter,
    project__name__contains="Foo").order_by("desc")

The Django Many-to-one documentation has this and other examples of following Foreign Keys using the Model API.

Good way of getting the user's location in Android

In my experience, I've found it best to go with the GPS fix unless it's not available. I don't know much about other location providers, but I know that for GPS there are a few tricks that can be used to give a bit of a ghetto precision measure. The altitude is often a sign, so you could check for ridiculous values. There is the accuracy measure on Android location fixes. Also if you can see the number of satellites used, this can also indicate the precision.

An interesting way of getting a better idea of the accuracy could be to ask for a set of fixes very rapidly, like ~1/sec for 10 seconds and then sleep for a minute or two. One talk I've been to has led to believe that some android devices will do this anyway. You would then weed out the outliers (I've heard Kalman filter mentioned here) and use some kind of centering strategy to get a single fix.

Obviously the depth you get to here depends on how hard your requirements are. If you have particularly strict requirement to get THE BEST location possible, I think you'll find that GPS and network location are as similar as apples and oranges. Also GPS can be wildly different from device to device.

Simplest JQuery validation rules example

rules: {
    cname: {
        required: true,
        minlength: 2
    }
},
messages: {
    cname: {
        required: "<li>Please enter a name.</li>",
        minlength: "<li>Your name is not long enough.</li>"
    }
}

What is the '.well' equivalent class in Bootstrap 4

Card seems to be "discarded" LOL, I found the "well" not working with bootstrap 4.3.1 and jQuery v3.4.1, just working fine with bootstrap 4.3.1 and jQuery v3.3.1. Hope it helps.

Increasing the timeout value in a WCF service

Under the Tools menu in Visual Studio 2008 (or 2005 if you have the right WCF stuff installed) there is an options called 'WCF Service Configuration Editor'.

From there you can change the binding options for both the client and the services, one of these options will be for time-outs.

Check box size change with CSS

You might want to do this.

input[type=checkbox] {

 -ms-transform: scale(2); /* IE */
 -moz-transform: scale(2); /* FF */
 -webkit-transform: scale(2); /* Safari and Chrome */
 -o-transform: scale(2); /* Opera */
  padding: 10px;
}

Get all Attributes from a HTML element with Javascript/jQuery

Roland Bouman's answer is the best, simple Vanilla way. I noticed some attempts at jQ plugs, but they just didn't seem "full" enough to me, so I made my own. The only setback so far has been inability to access dynamically added attrs without directly calling elm.attr('dynamicAttr'). However, this will return all natural attributes of a jQuery element object.

Plugin uses simple jQuery style calling:

$(elm).getAttrs();
// OR
$.getAttrs(elm);

You can also add a second string param for getting just one specific attr. This isn't really needed for one element selection, as jQuery already provides $(elm).attr('name'), however, my version of a plugin allows for multiple returns. So, for instance, a call like

$.getAttrs('*', 'class');

Will result in an array [] return of objects {}. Each object will look like:

{ class: 'classes names', elm: $(elm), index: i } // index is $(elm).index()

Plugin

;;(function($) {
    $.getAttrs || ($.extend({
        getAttrs: function() {
            var a = arguments,
                d, b;
            if (a.length)
                for (x in a) switch (typeof a[x]) {
                    case "object":
                        a[x] instanceof jQuery && (b = a[x]);
                        break;
                    case "string":
                        b ? d || (d = a[x]) : b = $(a[x])
                }
            if (b instanceof jQuery) {
                var e = [];
                if (1 == b.length) {
                    for (var f = 0, g = b[0].attributes, h = g.length; f < h; f++) a = g[f], e[a.name] = a.value;
                    b.data("attrList", e);
                    d && "all" != d && (e = b.attr(d))
                } else d && "all" != d ? b.each(function(a) {
                    a = {
                        elm: $(this),
                        index: $(this).index()
                    };
                    a[d] = $(this).attr(d);
                    e.push(a)
                }) : b.each(function(a) {
                    $elmRet = [];
                    for (var b = 0, d = this.attributes, f = d.length; b < f; b++) a = d[b], $elmRet[a.name] = a.value;
                    e.push({
                        elm: $(this),
                        index: $(this).index(),
                        attrs: $elmRet
                    });
                    $(this).data("attrList", e)
                });
                return e
            }
            return "Error: Cannot find Selector"
        }
    }), $.fn.extend({
        getAttrs: function() {
            var a = [$(this)];
            if (arguments.length)
                for (x in arguments) a.push(arguments[x]);
            return $.getAttrs.apply($, a)
        }
    }))
})(jQuery);

Complied

;;(function(c){c.getAttrs||(c.extend({getAttrs:function(){var a=arguments,d,b;if(a.length)for(x in a)switch(typeof a[x]){case "object":a[x]instanceof jQuery&&(b=a[x]);break;case "string":b?d||(d=a[x]):b=c(a[x])}if(b instanceof jQuery){if(1==b.length){for(var e=[],f=0,g=b[0].attributes,h=g.length;f<h;f++)a=g[f],e[a.name]=a.value;b.data("attrList",e);d&&"all"!=d&&(e=b.attr(d));for(x in e)e.length++}else e=[],d&&"all"!=d?b.each(function(a){a={elm:c(this),index:c(this).index()};a[d]=c(this).attr(d);e.push(a)}):b.each(function(a){$elmRet=[];for(var b=0,d=this.attributes,f=d.length;b<f;b++)a=d[b],$elmRet[a.name]=a.value;e.push({elm:c(this),index:c(this).index(),attrs:$elmRet});c(this).data("attrList",e);for(x in $elmRet)$elmRet.length++});return e}return"Error: Cannot find Selector"}}),c.fn.extend({getAttrs:function(){var a=[c(this)];if(arguments.length)for(x in arguments)a.push(arguments[x]);return c.getAttrs.apply(c,a)}}))})(jQuery);

jsFiddle

_x000D_
_x000D_
/*  BEGIN PLUGIN  */_x000D_
;;(function($) {_x000D_
 $.getAttrs || ($.extend({_x000D_
  getAttrs: function() {_x000D_
   var a = arguments,_x000D_
    c, b;_x000D_
   if (a.length)_x000D_
    for (x in a) switch (typeof a[x]) {_x000D_
     case "object":_x000D_
      a[x] instanceof f && (b = a[x]);_x000D_
      break;_x000D_
     case "string":_x000D_
      b ? c || (c = a[x]) : b = $(a[x])_x000D_
    }_x000D_
   if (b instanceof f) {_x000D_
    if (1 == b.length) {_x000D_
     for (var d = [], e = 0, g = b[0].attributes, h = g.length; e < h; e++) a = g[e], d[a.name] = a.value;_x000D_
     b.data("attrList", d);_x000D_
     c && "all" != c && (d = b.attr(c));_x000D_
     for (x in d) d.length++_x000D_
    } else d = [], c && "all" != c ? b.each(function(a) {_x000D_
     a = {_x000D_
      elm: $(this),_x000D_
      index: $(this).index()_x000D_
     };_x000D_
     a[c] = $(this).attr(c);_x000D_
     d.push(a)_x000D_
    }) : b.each(function(a) {_x000D_
     $elmRet = [];_x000D_
     for (var b = 0, c = this.attributes, e = c.length; b < e; b++) a = c[b], $elmRet[a.name] = a.value;_x000D_
     d.push({_x000D_
      elm: $(this),_x000D_
      index: $(this).index(),_x000D_
      attrs: $elmRet_x000D_
     });_x000D_
     $(this).data("attrList", d);_x000D_
     for (x in $elmRet) $elmRet.length++_x000D_
    });_x000D_
    return d_x000D_
   }_x000D_
   return "Error: Cannot find Selector"_x000D_
  }_x000D_
 }), $.fn.extend({_x000D_
  getAttrs: function() {_x000D_
   var a = [$(this)];_x000D_
   if (arguments.length)_x000D_
    for (x in arguments) a.push(arguments[x]);_x000D_
   return $.getAttrs.apply($, a)_x000D_
  }_x000D_
 }))_x000D_
})(jQuery);_x000D_
/*  END PLUGIN  */_x000D_
/*--------------------*/_x000D_
$('#bob').attr('bob', 'bill');_x000D_
console.log($('#bob'))_x000D_
console.log(new Array(50).join(' -'));_x000D_
console.log($('#bob').getAttrs('id'));_x000D_
console.log(new Array(50).join(' -'));_x000D_
console.log($.getAttrs('#bob'));_x000D_
console.log(new Array(50).join(' -'));_x000D_
console.log($.getAttrs('#bob', 'name'));_x000D_
console.log(new Array(50).join(' -'));_x000D_
console.log($.getAttrs('*', 'class'));_x000D_
console.log(new Array(50).join(' -'));_x000D_
console.log($.getAttrs('p'));_x000D_
console.log(new Array(50).join(' -'));_x000D_
console.log($('#bob').getAttrs('all'));_x000D_
console.log($('*').getAttrs('all'));
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>_x000D_
All of below is just for stuff for plugin to test on. See developer console for more details._x000D_
<hr />_x000D_
<div id="bob" class="wmd-button-bar"><ul id="wmd-button-row-27865269" class="wmd-button-row" style="display:none;">_x000D_
<div class="post-text" itemprop="text">_x000D_
<p>Roland Bouman's answer is the best, simple Vanilla way. I noticed some attempts at jQ plugs, but they just didn't seem "full" enough to me, so I made my own. The only setback so far has been inability to access dynamically added attrs without directly calling <code>elm.attr('dynamicAttr')</code>. However, this will return all natural attributes of a jQuery element object.</p>_x000D_
_x000D_
<p>Plugin uses simple jQuery style calling:</p>_x000D_
_x000D_
<pre class="default prettyprint prettyprinted"><code><span class="pln">$</span><span class="pun">(</span><span class="pln">elm</span><span class="pun">).</span><span class="pln">getAttrs</span><span class="pun">();</span><span class="pln">_x000D_
</span><span class="com">// OR</span><span class="pln">_x000D_
$</span><span class="pun">.</span><span class="pln">getAttrs</span><span class="pun">(</span><span class="pln">elm</span><span class="pun">);</span></code></pre>_x000D_
_x000D_
<p>You can also add a second string param for getting just one specific attr. This isn't really needed for one element selection, as jQuery already provides <code>$(elm).attr('name')</code>, however, my version of a plugin allows for multiple returns. So, for instance, a call like</p>_x000D_
_x000D_
<pre class="default prettyprint prettyprinted"><code><span class="pln">$</span><span class="pun">.</span><span class="pln">getAttrs</span><span class="pun">(</span><span class="str">'*'</span><span class="pun">,</span><span class="pln"> </span><span class="str">'class'</span><span class="pun">);</span></code></pre>_x000D_
_x000D_
<p>Will result in an array <code>[]</code> return of objects <code>{}</code>. Each object will look like:</p>_x000D_
_x000D_
<pre class="default prettyprint prettyprinted"><code><span class="pun">{</span><span class="pln"> </span><span class="kwd">class</span><span class="pun">:</span><span class="pln"> </span><span class="str">'classes names'</span><span class="pun">,</span><span class="pln"> elm</span><span class="pun">:</span><span class="pln"> $</span><span class="pun">(</span><span class="pln">elm</span><span class="pun">),</span><span class="pln"> index</span><span class="pun">:</span><span class="pln"> i </span><span class="pun">}</span><span class="pln"> </span><span class="com">// index is $(elm).index()</span></code></pre>_x000D_
    </div>_x000D_
  </div>
_x000D_
_x000D_
_x000D_

Get exit code of a background process

Another solution is to monitor processes via the proc filesystem (safer than ps/grep combo); when you start a process it has a corresponding folder in /proc/$pid, so the solution could be

#!/bin/bash
....
doSomething &
local pid=$!
while [ -d /proc/$pid ]; do # While directory exists, the process is running
    doSomethingElse
    ....
else # when directory is removed from /proc, process has ended
    wait $pid
    local exit_status=$?
done
....

Now you can use the $exit_status variable however you like.

What's the difference between the 'ref' and 'out' keywords?

Below I have shown an example using both Ref and out. Now, you all will be cleared about ref and out.

In below mentioned example when i comment //myRefObj = new myClass { Name = "ref outside called!! " }; line, will get an error saying "Use of unassigned local variable 'myRefObj'", but there is no such error in out.

Where to use Ref: when we are calling a procedure with an in parameter and the same parameter will be used to store the output of that proc.

Where to use Out: when we are calling a procedure with no in parameter and teh same param will be used to return the value from that proc. Also note the output

public partial class refAndOutUse : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        myClass myRefObj;
        myRefObj = new myClass { Name = "ref outside called!!  <br/>" };
        myRefFunction(ref myRefObj);
        Response.Write(myRefObj.Name); //ref inside function

        myClass myOutObj;
        myOutFunction(out myOutObj);
        Response.Write(myOutObj.Name); //out inside function
    }

    void myRefFunction(ref myClass refObj)
    {
        refObj.Name = "ref inside function <br/>";
        Response.Write(refObj.Name); //ref inside function
    }
    void myOutFunction(out myClass outObj)
    {
        outObj = new myClass { Name = "out inside function <br/>" }; 
        Response.Write(outObj.Name); //out inside function
    }
}

public class myClass
{
    public string Name { get; set; }
} 

How to rename a directory/folder on GitHub website?

I had an issue with github missing out on some case sensitive changes to folders. I needed to keep migration history so an example of how I changed "basicApp" folder in github to "basicapp"

$ git ls-files
$ git mv basicApp basicapp_temp
$ git add .
$ git commit -am "temporary change"
$ git push origin master
$ git mv basicapp_temp basicapp
$ git add .
$ git commit -am "change to desired name"
$ git push origin master

PS: git ls-files will show you how github sees your folder name

.htaccess rewrite to redirect root URL to subdirectory

This will try the subdir if the file doesn't exist in the root. Needed this as I moved a basic .html website that expects to be ran at the root level and pushed it to a subdir. Only works if all files are flat (no .htaccess trickery in the subdir possible). Useful for linked things like css and js files.

# Internal Redirect to subdir if file is found there.
RewriteEngine on
RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_URI} !-s
RewriteCond %{DOCUMENT_ROOT}/subdir/%{REQUEST_URI} -s
RewriteRule ^(.*)$ /subdir/$1 [L]

How to determine if a list of polygon points are in clockwise order?

Find the vertex with smallest y (and largest x if there are ties). Let the vertex be A and the previous vertex in the list be B and the next vertex in the list be C. Now compute the sign of the cross product of AB and AC.


References:

How do you run a js file using npm scripts?

{ "scripts" :
  { "build": "node build.js"}
}

npm run build OR npm run-script build


{
  "name": "build",
  "version": "1.0.0",
  "scripts": {
    "start": "node build.js"
  }
}

npm start


NB: you were missing the { brackets } and the node command

folder structure is fine:

+ build
  - package.json
  - build.js

Can a website detect when you are using Selenium with chromedriver?

The bot detection I've seen seems more sophisticated or at least different than what I've read through in the answers below.

EXPERIMENT 1:

  1. I open a browser and web page with Selenium from a Python console.
  2. The mouse is already at a specific location where I know a link will appear once the page loads. I never move the mouse.
  3. I press the left mouse button once (this is necessary to take focus from the console where Python is running to the browser).
  4. I press the left mouse button again (remember, cursor is above a given link).
  5. The link opens normally, as it should.

EXPERIMENT 2:

  1. As before, I open a browser and the web page with Selenium from a Python console.

  2. This time around, instead of clicking with the mouse, I use Selenium (in the Python console) to click the same element with a random offset.

  3. The link doesn't open, but I am taken to a sign up page.

IMPLICATIONS:

  • opening a web browser via Selenium doesn't preclude me from appearing human
  • moving the mouse like a human is not necessary to be classified as human
  • clicking something via Selenium with an offset still raises the alarm

Seems mysterious, but I guess they can just determine whether an action originates from Selenium or not, while they don't care whether the browser itself was opened via Selenium or not. Or can they determine if the window has focus? Would be interesting to hear if anyone has any insights.

How do I use su to execute the rest of the bash script as that user?

This worked for me

I split out my "provisioning" from my "startup".

 # Configure everything else ready to run 
  config.vm.provision :shell, path: "provision.sh"
  config.vm.provision :shell, path: "start_env.sh", run: "always"

then in my start_env.sh

#!/usr/bin/env bash

echo "Starting Server Env"
#java -jar /usr/lib/node_modules/selenium-server-standalone-jar/jar/selenium-server-standalone-2.40.0.jar  &
#(cd /vagrant_projects/myproj && sudo -u vagrant -H sh -c "nohup npm install 0<&- &>/dev/null &;bower install 0<&- &>/dev/null &")
cd /vagrant_projects/myproj
nohup grunt connect:server:keepalive 0<&- &>/dev/null &
nohup apimocker -c /vagrant_projects/myproj/mock_api_data/config.json 0<&- &>/dev/null &

Why does MSBuild look in C:\ for Microsoft.Cpp.Default.props instead of c:\Program Files (x86)\MSBuild? ( error MSB4019)

For those who didn't follow the MS proscribed order (see Xv's answer) you can still fix the problem.

MSBuild uses the VCTargetsPath to locate default cpp properties but cannot because the registry lacks this String Value.

Check for the String Value

  • Launch regedit
  • Navigator to HKLM\SOFTWARE\Microsoft\MSBuild\ToolsVersions\4.0
  • Inspect VCTargetsPath key. The value should = "$(MSBuildExtensionsPath32)\Microsoft.Cpp\v4.0\"

To fix

  • Launch regedit Navigator to HKLM\SOFTWARE\Microsoft\MSBuild\ToolsVersions\4.0
  • Add String Value VCTargetsPath
  • Set Value to "$(MSBuildExtensionsPath32)\Microsoft.Cpp\v4.0\"

Note: HKLM stands for HKEY_LOCAL_MACHINE.

Generate random string/characters in JavaScript

in below code i am generating random code for 8 characters

function RandomUnique(){
                    var charBank = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ012346789";
                    var random= '';
                    var howmanycharacters = 8;
                    for (var i = 0; i < howmanycharacters ; i++) {
                        random+= charBank[parseInt(Math.random() * charBank.lenght)];
                    }
                    return random;
                }
        var random = RandomUnique();
        console.log(random);

Iterating through all the cells in Excel VBA or VSTO 2005

My VBA skills are a little rusty, but this is the general idea of what I'd do.
The easiest way to do this would be to iterate through a loop for every column:

public sub CellProcessing()
on error goto errHandler

    dim MAX_ROW as Integer   'how many rows in the spreadsheet
    dim i as Integer
    dim cols as String

    for i = 1 to MAX_ROW
        'perform checks on the cell here
        'access the cell with Range("A" & i) to get cell A1 where i = 1
    next i

exitHandler:
    exit sub
errHandler:
    msgbox "Error " & err.Number & ": " & err.Description
    resume exitHandler
end sub

it seems that the color syntax highlighting doesn't like vba, but hopefully this will help somewhat (at least give you a starting point to work from).

  • Brisketeer

Show space, tab, CRLF characters in editor of Visual Studio

Edit > Advanced > View White Space. The keyboard shortcut is CTRL+R, CTRL+W. The command is called Edit.ViewWhiteSpace.

It works in all Visual Studio versions at least since Visual Studio 2010, the current one being Visual Studio 2019 (at time of writing). In Visual Studio 2013, you can also use CTRL+E, S or CTRL+E, CTRL+S.

By default, end of line markers are not visualized. This functionality is provided by the End of the Line extension.

Validate form field only on submit or user input

You can use angularjs form state form.$submitted. Initially form.$submitted value will be false and will became true after successful form submit.

Checkbox for nullable boolean

My model has a boolean that has to be nullable

Why? This doesn't make sense. A checkbox has two states: checked/unchecked, or True/False if you will. There is no third state.

Or wait you are using your domain models in your views instead of view models? That's your problem. So the solution for me is to use a view model in which you will define a simple boolean property:

public class MyViewModel
{
    public bool Foo { get; set; }
}

and now you will have your controller action pass this view model to the view and generate the proper checkbox.

Silent installation of a MSI package

You should be able to use the /quiet or /qn options with msiexec to perform a silent install.

MSI packages export public properties, which you can set with the PROPERTY=value syntax on the end of the msiexec parameters.

For example, this command installs a package with no UI and no reboot, with a log and two properties:

msiexec /i c:\path\to\package.msi /quiet /qn /norestart /log c:\path\to\install.log PROPERTY1=value1 PROPERTY2=value2

You can read the options for msiexec by just running it with no options from Start -> Run.

What does Html.HiddenFor do?

And to consume the hidden ID input back on your Edit action method:

[HttpPost]
public ActionResult Edit(FormCollection collection)
{
    ViewModel.ID = Convert.ToInt32(collection["ID"]);
}

Locate the nginx.conf file my nginx is actually using

Running nginx -t through your commandline will issue out a test and append the output with the filepath to the configuration file (with either an error or success message).

Mockito: Inject real objects into private @Autowired fields

I know this is an old question, but we were faced with the same problem when trying to inject Strings. So we invented a JUnit5/Mockito extension that does exactly what you want: https://github.com/exabrial/mockito-object-injection

EDIT:

@InjectionMap
 private Map<String, Object> injectionMap = new HashMap<>();

 @BeforeEach
 public void beforeEach() throws Exception {
  injectionMap.put("securityEnabled", Boolean.TRUE);
 }

 @AfterEach
 public void afterEach() throws Exception {
  injectionMap.clear();
 }

Git: copy all files in a directory from another branch

If there are no spaces in paths, and you are interested, like I was, in files of specific extension only, you can use

git checkout otherBranch -- $(git ls-tree --name-only -r otherBranch | egrep '*.java')

Convert decimal to binary in python

For the sake of completion: if you want to convert fixed point representation to its binary equivalent you can perform the following operations:

  1. Get the integer and fractional part.

    from decimal import *
    a = Decimal(3.625)
    a_split = (int(a//1),a%1)
    
  2. Convert the fractional part in its binary representation. To achieve this multiply successively by 2.

    fr = a_split[1]
    str(int(fr*2)) + str(int(2*(fr*2)%1)) + ...
    

You can read the explanation here.

Swift alert view with OK and Cancel: which button tapped?

You can easily do this by using UIAlertController

let alertController = UIAlertController(
       title: "Your title", message: "Your message", preferredStyle: .alert)
let defaultAction = UIAlertAction(
       title: "Close Alert", style: .default, handler: nil)
//you can add custom actions as well 
alertController.addAction(defaultAction)

present(alertController, animated: true, completion: nil)

.

Reference: iOS Show Alert

Fastest way to tell if two files have the same contents in Unix/Linux?

I believe cmp will stop at the first byte difference:

cmp --silent $old $new || echo "files are different"

Getting Textbox value in Javascript

This is because ASP.NET it changing the Id of your textbox, if you run your page, and do a view source, you will see the text box id is something like

ctl00_ContentColumn_txt_model_code

There are a few ways round this:

Use the actual control name:

var TestVar = document.getElementById('ctl00_ContentColumn_txt_model_code').value;

use the ClientID property within ASP script tags

document.getElementById('<%= txt_model_code.ClientID %>').value;

Or if you are running .NET 4 you can use the new ClientIdMode property, see this link for more details.

http://weblogs.asp.net/scottgu/archive/2010/03/30/cleaner-html-markup-with-asp-net-4-web-forms-client-ids-vs-2010-and-net-4-0-series.aspx1

Basic example of using .ajax() with JSONP?

There is even easier way how to work with JSONP using jQuery

$.getJSON("http://example.com/something.json?callback=?", function(result){
   //response data are now in the result variable
   alert(result);
});

The ? on the end of the URL tells jQuery that it is a JSONP request instead of JSON. jQuery registers and calls the callback function automatically.

For more detail refer to the jQuery.getJSON documentation.

Linux/Unix command to determine if process is running?

This approach can be used in case commands 'ps', 'pidof' and rest are not available. I personally use procfs very frequently in my tools/scripts/programs.

   egrep -m1  "mysqld$|httpd$" /proc/[0-9]*/status | cut -d'/' -f3

Little explanation what is going on:

  1. -m1 - stop process on first match
  2. "mysqld$|httpd$" - grep will match lines which ended on mysqld OR httpd
  3. /proc/[0-9]* - bash will match line which started with any number
  4. cut - just split the output by delimiter '/' and extract field 3

How to get JSON from webpage into Python script

Get data from the URL and then call json.loads e.g.

Python3 example:

import urllib.request, json 
with urllib.request.urlopen("http://maps.googleapis.com/maps/api/geocode/json?address=google") as url:
    data = json.loads(url.read().decode())
    print(data)

Python2 example:

import urllib, json
url = "http://maps.googleapis.com/maps/api/geocode/json?address=google"
response = urllib.urlopen(url)
data = json.loads(response.read())
print data

The output would result in something like this:

{
"results" : [
    {
    "address_components" : [
        {
            "long_name" : "Charleston and Huff",
            "short_name" : "Charleston and Huff",
            "types" : [ "establishment", "point_of_interest" ]
        },
        {
            "long_name" : "Mountain View",
            "short_name" : "Mountain View",
            "types" : [ "locality", "political" ]
        },
        {
...

Run .php file in Windows Command Prompt (cmd)

It seems your question is very much older. But I just saw it. I searched(not in google) and found My Answer.

So I am writing its solution so that others may get help from it.

Here is my solution.

Unlike the other answers, you don't need to setup environments.

all you need is just to write php index.php if index.php is your file name.

then you will see that, the file compiled and showing it's desired output.

C++ Best way to get integer division and remainder

On x86 at least, g++ 4.6.1 just uses IDIVL and gets both from that single instruction.

C++ code:

void foo(int a, int b, int* c, int* d)
{
  *c = a / b;
  *d = a % b;
}

x86 code:

__Z3fooiiPiS_:
LFB4:
    movq    %rdx, %r8
    movl    %edi, %edx
    movl    %edi, %eax
    sarl    $31, %edx
    idivl   %esi
    movl    %eax, (%r8)
    movl    %edx, (%rcx)
    ret

img onclick call to JavaScript function

In response to the good solution from macek. The solution didn't work for me. I have to bind the values of the datas to the export function. This solution works for me:

function exportToForm(a, b, c, d, e) {
  console.log(a, b, c, d, e);
}

var images = document.getElementsByTagName("img");

for (var i=0, len=images.length, img; i<len; i++) {
  var img = images[i];
  var boundExportToForm = exportToForm.bind(undefined, 
          img.getAttribute("data-a"), 
            img.getAttribute("data-b"),
            img.getAttribute("data-c"),
            img.getAttribute("data-d"),
            img.getAttribute("data-e"))

  img.addEventListener("click", boundExportToForm);
  }

Get a particular cell value from HTML table using JavaScript

You can also use the DOM way to obtain the cell value: Cells[0].firstChild.data

Read more on that in my post at http://js-code.blogspot.com/2009/03/how-to-change-html-table-cell-value.html

Copy files on Windows Command Line with Progress

You could easily write a program to do that, I've got several that I've written, that display bytes copied as the file is being copied. If you're interested, comment and I'll post a link to one.

How to get only the last part of a path in Python?

I was searching for a solution to get the last foldername where the file is located, I just used split two times, to get the right part. It's not the question but google transfered me here.

pathname = "/folderA/folderB/folderC/folderD/filename.py"
head, tail = os.path.split(os.path.split(pathname)[0])
print(head + "   "  + tail)

filename.whl is not supported wheel on this platform

I come across this problem because the wrong name of my package (scipy-0.17.0-cp27-none-win_amd64 (1)), after I delete the '(1)' and change the package to scipy-0.17.0-cp27-none-win_amd64, the problem got resolved.

Flutter - Wrap text on overflow, like insert ellipsis or fade

Depending on your situation, I think this is the best approach below.

final maxWidth = MediaQuery.of(context).size.width * 0.4;
Container(
        textAlign: TextAlign.center),
        child: Text('This is long text',
        constraints: BoxConstraints(maxWidth: maxWidth),
),

Add CSS3 transition expand/collapse

http://jsfiddle.net/Bq6eK/215/

I did not modify your code for this solution, I wrote my own instead. My solution isn't quite what you asked for, but maybe you could build on it with existing knowledge. I commented the code as well so you know what exactly I'm doing with the changes.

As a solution to "avoid setting the height in JavaScript", I just made 'maxHeight' a parameter in the JS function called toggleHeight. Now it can be set in the HTML for each div of class expandable.

I'll say this up front, I'm not super experienced with front-end languages, and there's an issue where I need to click the 'Show/hide' button twice initially before the animation starts. I suspect it's an issue with focus.

The other issue with my solution is that you can actually figure out what the hidden text is without pressing the show/hide button just by clicking in the div and dragging down, you can highlight the text that's not visible and paste it to a visible space.

My suggestion for a next step on top of what I've done is to make it so that the show/hide button changes dynamically. I think you can figure out how to do that with what you already seem to know about showing and hiding text with JS.

How do you kill a Thread in Java?

There is a way how you can do it. But if you had to use it, either you are a bad programmer or you are using a code written by bad programmers. So, you should think about stopping being a bad programmer or stopping using this bad code. This solution is only for situations when THERE IS NO OTHER WAY.

Thread f = <A thread to be stopped>
Method m = Thread.class.getDeclaredMethod( "stop0" , new Class[]{Object.class} );
m.setAccessible( true );
m.invoke( f , new ThreadDeath() );

Write variable to a file in Ansible

Based on Ramon's answer I run into an error. The problem where spaces in the JSON I tried to write I got it fixed by changing the task in the playbook to look like:

- copy:
    content: "{{ your_json_feed }}"
    dest: "/path/to/destination/file"

As of now I am not sure why this was needed. My best guess is that it had something to do with how variables are replaced in Ansible and the resulting file is parsed.

JQuery select2 set default value from an option in list?

Came from the future? Looking for the ajax source default value ?

// Set up the Select2 control
$('#mySelect2').select2({
    ajax: {
        url: '/api/students'
    }
});

// Fetch the preselected item, and add to the control
var studentSelect = $('#mySelect2');
$.ajax({
    type: 'GET',
    url: '/api/students/s/' + studentId
}).then(function (data) {
    // create the option and append to Select2
    var option = new Option(data.full_name, data.id, true, true);
    studentSelect.append(option).trigger('change');

    // manually trigger the `select2:select` event
    studentSelect.trigger({
        type: 'select2:select',
        params: {
            data: data
        }
    });
});

You're welcome.

Reference: https://select2.org/programmatic-control/add-select-clear-items#preselecting-options-in-an-remotely-sourced-ajax-select2

Parse JSON in C#

Google Map API request and parse DirectionsResponse with C#, change the json in your url to xml and use the following code to turn the result into a usable C# Generic List Object.

Took me a while to make. But here it is

var url = String.Format("http://maps.googleapis.com/maps/api/directions/xml?...");
var result = new System.Net.WebClient().DownloadString(url);
var doc = XDocument.Load(new StringReader(result));

var DirectionsResponse = doc.Elements("DirectionsResponse").Select(l => new
{
    Status = l.Elements("status").Select(q => q.Value).FirstOrDefault(),
    Route = l.Descendants("route").Select(n => new
    {
        Summary = n.Elements("summary").Select(q => q.Value).FirstOrDefault(),
        Leg = n.Elements("leg").ToList().Select(o => new
        {
            Step = o.Elements("step").Select(p => new
            {
                Travel_Mode = p.Elements("travel_mode").Select(q => q.Value).FirstOrDefault(),
                Start_Location = p.Elements("start_location").Select(q => new
                {
                    Lat = q.Elements("lat").Select(r => r.Value).FirstOrDefault(),
                    Lng = q.Elements("lng").Select(r => r.Value).FirstOrDefault()
                }).FirstOrDefault(),
                End_Location = p.Elements("end_location").Select(q => new
                {
                    Lat = q.Elements("lat").Select(r => r.Value).FirstOrDefault(),
                    Lng = q.Elements("lng").Select(r => r.Value).FirstOrDefault()
                }).FirstOrDefault(),
                Polyline = p.Elements("polyline").Select(q => new
                {
                    Points = q.Elements("points").Select(r => r.Value).FirstOrDefault()
                }).FirstOrDefault(),
                Duration = p.Elements("duration").Select(q => new
                {
                    Value = q.Elements("value").Select(r => r.Value).FirstOrDefault(),
                    Text = q.Elements("text").Select(r => r.Value).FirstOrDefault(),
                }).FirstOrDefault(),
                Html_Instructions = p.Elements("html_instructions").Select(q => q.Value).FirstOrDefault(),
                Distance = p.Elements("distance").Select(q => new
                {
                    Value = q.Elements("value").Select(r => r.Value).FirstOrDefault(),
                    Text = q.Elements("text").Select(r => r.Value).FirstOrDefault(),
                }).FirstOrDefault()
            }).ToList(),
            Duration = o.Elements("duration").Select(p => new
            {
                Value = p.Elements("value").Select(q => q.Value).FirstOrDefault(),
                Text = p.Elements("text").Select(q => q.Value).FirstOrDefault()
            }).FirstOrDefault(),
            Distance = o.Elements("distance").Select(p => new
            {
                Value = p.Elements("value").Select(q => q.Value).FirstOrDefault(),
                Text = p.Elements("text").Select(q => q.Value).FirstOrDefault()
            }).FirstOrDefault(),
            Start_Location = o.Elements("start_location").Select(p => new
            {
                Lat = p.Elements("lat").Select(q => q.Value).FirstOrDefault(),
                Lng = p.Elements("lng").Select(q => q.Value).FirstOrDefault()
            }).FirstOrDefault(),
            End_Location = o.Elements("end_location").Select(p => new
            {
                Lat = p.Elements("lat").Select(q => q.Value).FirstOrDefault(),
                Lng = p.Elements("lng").Select(q => q.Value).FirstOrDefault()
            }).FirstOrDefault(),
            Start_Address = o.Elements("start_address").Select(q => q.Value).FirstOrDefault(),
            End_Address = o.Elements("end_address").Select(q => q.Value).FirstOrDefault()
        }).ToList(),
        Copyrights = n.Elements("copyrights").Select(q => q.Value).FirstOrDefault(),
        Overview_polyline = n.Elements("overview_polyline").Select(q => new
        {
            Points = q.Elements("points").Select(r => r.Value).FirstOrDefault()
        }).FirstOrDefault(),
        Waypoint_Index = n.Elements("waypoint_index").Select(o => o.Value).ToList(),
        Bounds = n.Elements("bounds").Select(q => new
        {
            SouthWest = q.Elements("southwest").Select(r => new
            {
                Lat = r.Elements("lat").Select(s => s.Value).FirstOrDefault(),
                Lng = r.Elements("lng").Select(s => s.Value).FirstOrDefault()
            }).FirstOrDefault(),
            NorthEast = q.Elements("northeast").Select(r => new
            {
                Lat = r.Elements("lat").Select(s => s.Value).FirstOrDefault(),
                Lng = r.Elements("lng").Select(s => s.Value).FirstOrDefault()
            }).FirstOrDefault(),
        }).FirstOrDefault()
    }).FirstOrDefault()
}).FirstOrDefault();

I hope this will help someone.

Creating an XmlNode/XmlElement in C# without an XmlDocument?

You need Linq - System.Xml.Linq to be precise.

You can create XML using XElement from scratch - that should pretty much sort you out.

How to put a text beside the image?

I had a similar issue, where I had one div holding the image, and one div holding the text. The reason mine wasn't working, was that the div holding the image had display: inline-block while the div holding the text had display: inline.

I changed it to both be display: inline and it worked.

Here's a solution for a basic header section with a logo, title and tagline:

HTML

<div class="site-branding">
  <div class="site-branding-logo">
    <img src="add/Your/URI/Here" alt="what Is The Image About?" />
  </div>
</div>
<div class="site-branding-text">
  <h1 id="site-title">Site Title</h1>
  <h2 id="site-tagline">Site Tagline</h2>
</div>

CSS

div.site-branding { /* Position Logo and Text  */
  display: inline-block;
  vertical-align: middle;
}

div.site-branding-logo { /* Position logo within site-branding */
  display: inline;
  vertical-align: middle;
}

div.site-branding-text { /* Position text within site-branding */
    display: inline;
    width: 350px;
    margin: auto 0;
    vertical-align: middle;
}

div.site-branding-title { /* Position title within text */
    display: inline;
}

div.site-branding-tagline { /* Position tagline within text */
    display: block;
}

Converting HTML to Excel?

We copy/paste html pages from our ERP to Excel using "paste special.. as html/unicode" and it works quite well with tables.

PHP Warning: PHP Startup: Unable to load dynamic library

It means there is an extension=... or zend_extension=... line in one of your php configuration files (php.ini, or another close to it) that is trying to load that extension : ixed.5.2.lin

Unfortunately that file or path doesn't exist or the permissions are incorrect.

  1. Try to search in the .ini files that are loaded by PHP (phpinfo() can indicate which ones are) - one of them should try to load that extension.
  2. Either correct the path to the file or comment out the corresponding line.

C++ pointer to objects

Simple solution for cast pointer to object

Online demo

class myClass
{
  public:
  void sayHello () {
    cout << "Hello";
  }
};

int main ()
{
  myClass* myPointer;
  myClass myObject = myClass(* myPointer); // Cast pointer to object
  myObject.sayHello();

  return 0;
}

How to retrieve current workspace using Jenkins Pipeline Groovy script?

This is where you can find the answer in the job-dsl-plugin code.

Basically you can do something like this:

readFileFromWorkspace('src/main/groovy/com/groovy/jenkins/scripts/enable_safehtml.groovy')

How to get the Android device's primary e-mail address

Add this single line in manifest (for permission)

<uses-permission android:name="android.permission.GET_ACCOUNTS" />

Then paste this code in your activity

private ArrayList<String> getPrimaryMailId() {
    ArrayList<String> accountsList = new ArrayList<String>();
    try {
        Account[] accounts = AccountManager.get(this).getAccountsByType("com.google");
        for (Account account : accounts) {
            accountsList.add(account.name);
            Log.e("GetPrimaryMailId ", account.name);
        }
    } catch (Exception e) {
        Log.e("GetPrimaryMailId", " Exception : " + e);
    }
    return accountsList;
}

Delegation: EventEmitter or Observable in Angular

You need to use the Navigation component in the template of ObservingComponent ( dont't forget to add a selector to Navigation component .. navigation-component for ex )

<navigation-component (navchange)='onNavGhange($event)'></navigation-component>

And implement onNavGhange() in ObservingComponent

onNavGhange(event) {
  console.log(event);
}

Last thing .. you don't need the events attribute in @Componennt

events : ['navchange'], 

how to convert string into time format and add two hours

This will give you the time you want (eg: 21:31 PM)

//Add 2 Hours to just TIME
SimpleDateFormat formatter = new SimpleDateFormat("HH:mm:ss a");
Date date2 = formatter.parse("19:31:51 PM");
Calendar cal2 = Calendar.getInstance();
cal2.setTime(date2);
cal2.add(Calendar.HOUR_OF_DAY, 2);
SimpleDateFormat printTimeFormat = new SimpleDateFormat("HH:mm a");
System.out.println(printTimeFormat.format(cal2.getTime())); 

What's the difference between xsd:include and xsd:import?

Another difference is that <import> allows importing by referring to another namespace. <include> only allows importing by referring to a URI of intended include schema. That is definitely another difference than inter-intra namespace importing.

For example, the xml schema validator may already know the locations of all schemas by namespace already. Especially considering that referring to XML namespaces by URI may be problematic on different systems where classpath:// means nothing, or where http:// isn't allowed, or where some URI doesn't point to the same thing as it does on another system.

Code sample of valid and invalid imports and includes:

Valid:

<xsd:import namespace="some/name/space"/>
<xsd:import schemaLocation="classpath://mine.xsd"/>

<xsd:include schemaLocation="classpath://mine.xsd"/>

Invalid:

<xsd:include namespace="some/name/space"/>

How to get second-highest salary employees in a table

I think you would want to use DENSE_RANK as you don't know how many employees have the same salary and you did say you wanted nameS of employees.

CREATE TABLE #Test
(
    Id INT,
    Name NVARCHAR(12),
    Salary MONEY
)

SELECT x.Name, x.Salary
FROM
        (
        SELECT  Name, Salary, DENSE_RANK() OVER (ORDER BY Salary DESC) as Rnk
        FROM    #Test
        ) x
WHERE x.Rnk = 2

ROW_NUMBER would give you unique numbering even if the salaries tied, and plain RANK would not give you a '2' as a rank if you had multiple people tying for highest salary. I've corrected this as DENSE_RANK does the best job for this.

JPA mapping: "QuerySyntaxException: foobar is not mapped..."

You have declared your Class as:

@Table( name = "foobar" )
public class FooBar {

You need to write the Class Name for the search.
from FooBar

What is the difference between find(), findOrFail(), first(), firstOrFail(), get(), list(), toArray()

  1. find($id) takes an id and returns a single model. If no matching model exist, it returns null.

  2. findOrFail($id) takes an id and returns a single model. If no matching model exist, it throws an error1.

  3. first() returns the first record found in the database. If no matching model exist, it returns null.

  4. firstOrFail() returns the first record found in the database. If no matching model exist, it throws an error1.

  5. get() returns a collection of models matching the query.

  6. pluck($column) returns a collection of just the values in the given column. In previous versions of Laravel this method was called lists.

  7. toArray() converts the model/collection into a simple PHP array.


Note: a collection is a beefed up array. It functions similarly to an array, but has a lot of added functionality, as you can see in the docs.

Unfortunately, PHP doesn't let you use a collection object everywhere you can use an array. For example, using a collection in a foreach loop is ok, put passing it to array_map is not. Similarly, if you type-hint an argument as array, PHP won't let you pass it a collection. Starting in PHP 7.1, there is the iterable typehint, which can be used to accept both arrays and collections.

If you ever want to get a plain array from a collection, call its all() method.


1 The error thrown by the findOrFail and firstOrFail methods is a ModelNotFoundException. If you don't catch this exception yourself, Laravel will respond with a 404, which is what you want most of the time.

Are there pointers in php?

No, As others said, "There is no Pointer in PHP." and I add, there is nothing RAM_related in PHP.

And also all answers are clear. But there were points being left out that I could not resist!

There are number of things that acts similar to pointers

  • eval construct (my favorite and also dangerous)
  • $GLOBALS variable
  • Extra '$' sign Before Variables (Like prathk mentioned)
  • References

First one

At first I have to say that PHP is really powerful language, knowing there is a construct named "eval", so you can create your PHP code while running it! (really cool!)

although there is the danger of PHP_Injection which is far more destructive that SQL_Injection. Beware!

example:

Code:

$a='echo "Hello World.";';
eval ($a);

Output

Hello World.

So instead of using a pointer to act like another Variable, You Can Make A Variable From Scratch!


Second one

$GLOBAL variable is pretty useful, You can access all variables by using its keys.

example:

Code:

$three="Hello";$variable=" Amazing ";$names="World";
$arr = Array("three","variable","names");
foreach($arr as $VariableName)
    echo $GLOBALS[$VariableName];

Output

Hello Amazing World

Note: Other superglobals can do the same trick in smaller scales.


Third one

You can add as much as '$'s you want before a variable, If you know what you're doing.

example:

Code:

$a="b";
$b="c";
$c="d";
$d="e";
$e="f";

echo $a."-";
echo $$a."-";   //Same as $b
echo $$$a."-";  //Same as $$b or $c
echo $$$$a."-"; //Same as $$$b or $$c or $d
echo $$$$$a;    //Same as $$$$b or $$$c or $$d or $e

Output

b-c-d-e-f


Last one

Reference are so close to pointers, but you may want to check this link for more clarification.

example 1:

Code:

$a="Hello";
$b=&$a;
$b="yello";
echo $a;

Output

yello

example 2:

Code:

function junk(&$tion)
{$GLOBALS['a'] = &$tion;}
$a="-Hello World<br>";
$b="-To You As Well";
echo $a;
junk($b);
echo $a;

Output

-Hello World

-To You As Well

Hope It Helps.

How do I loop through items in a list box and then remove those item?

Here my solution without going backward and without a temporary list

while (listBox1.Items.Count > 0)
{
  string s = listBox1.Items[0] as string;
  // do something with s
  listBox1.Items.RemoveAt(0);
}

How correctly produce JSON by RESTful web service?

@GET
@Path("/friends")
@Produces(MediaType.APPLICATION_JSON)
public String getFriends() {

    // here you can return any bean also it will automatically convert into json 
    return "{'friends': ['Michael', 'Tom', 'Daniel', 'John', 'Nick']}";
}

Rails: Address already in use - bind(2) (Errno::EADDRINUSE)

To kill the puma process first run

    lsof -wni tcp:3000 

to show what is using port 3000. Then use the PID that comes with the result to run the kill process.

For example after running lsof -wni tcp:3000 you might get something like

    COMMAND  PID  USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
    ruby    3366 dummy    8u  IPv4  16901      0t0  TCP 127.0.0.1:3000 (LISTEN)

Now run the following to kill the process. (where 3366 is the PID)

kill -9 3366

Should resolve the issue

Twitter API - Display all tweets with a certain hashtag?

UPDATE for v1.1:

Rather than giving q="search_string" give it q="hashtag" in URL encoded form to return results with HASHTAG ONLY. So your query would become:

    GET https://api.twitter.com/1.1/search/tweets.json?q=%23freebandnames

%23 is URL encoded form of #. Try the link out in your browser and it should work.

You can optimize the query by adding since_id and max_id parameters detailed here. Hope this helps !

Note: Search API is now a OAUTH authenticated call, so please include your access_tokens to the above call

Updated

Twitter Search doc link: https://developer.twitter.com/en/docs/tweets/search/api-reference/get-search-tweets.html

Put buttons at bottom of screen with LinearLayout?

<LinearLayout
 android:id="@+id/LinearLayouts02"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 android:gravity="bottom|end">

<TextView
android:id="@+id/texts1"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:layout_weight="2"
android:text="@string/forgotpass"
android:padding="7dp"
android:gravity="bottom|center_horizontal"
android:paddingLeft="10dp"
android:layout_marginBottom="30dp"
android:bottomLeftRadius="10dp"
android:bottomRightRadius="50dp"
android:fontFamily="sans-serif-condensed"
android:textColor="@color/colorAccent"
android:textStyle="bold"
android:textSize="16sp"
android:topLeftRadius="10dp"
android:topRightRadius="10dp"/>

</LinearLayout>

How to get all child inputs of a div element (jQuery)

If you are using a framework like Ruby on Rails or Spring MVC you may need to use divs with square braces or other chars, that are not allowed you can use document.getElementById and this solution still works if you have multiple inputs with the same type.

var div = document.getElementById(divID);
$(div).find('input:text, input:password, input:file, select, textarea')
        .each(function() {
            $(this).val('');
        });
$(div).find('input:radio, input:checkbox').each(function() {
    $(this).removeAttr('checked');
    $(this).removeAttr('selected');
});

This examples shows how to clear the inputs, for you example you'll need to change it.

Append an object to a list in R in amortized constant time, O(1)?

In the other answers, only the list approach results in O(1) appends, but it results in a deeply nested list structure, and not a plain single list. I have used the below datastructures, they supports O(1) (amortized) appends, and allow the result to be converted back to a plain list.

expandingList <- function(capacity = 10) {
    buffer <- vector('list', capacity)
    length <- 0

    methods <- list()

    methods$double.size <- function() {
        buffer <<- c(buffer, vector('list', capacity))
        capacity <<- capacity * 2
    }

    methods$add <- function(val) {
        if(length == capacity) {
            methods$double.size()
        }

        length <<- length + 1
        buffer[[length]] <<- val
    }

    methods$as.list <- function() {
        b <- buffer[0:length]
        return(b)
    }

    methods
}

and

linkedList <- function() {
    head <- list(0)
    length <- 0

    methods <- list()

    methods$add <- function(val) {
        length <<- length + 1
        head <<- list(head, val)
    }

    methods$as.list <- function() {
        b <- vector('list', length)
        h <- head
        for(i in length:1) {
            b[[i]] <- head[[2]]
            head <- head[[1]]
        }
        return(b)
    }
    methods
}

Use them as follows:

> l <- expandingList()
> l$add("hello")
> l$add("world")
> l$add(101)
> l$as.list()
[[1]]
[1] "hello"

[[2]]
[1] "world"

[[3]]
[1] 101

These solutions could be expanded into full objects that support al list-related operations by themselves, but that will remain as an exercise for the reader.

Another variant for a named list:

namedExpandingList <- function(capacity = 10) {
    buffer <- vector('list', capacity)
    names <- character(capacity)
    length <- 0

    methods <- list()

    methods$double.size <- function() {
        buffer <<- c(buffer, vector('list', capacity))
        names <<- c(names, character(capacity))
        capacity <<- capacity * 2
    }

    methods$add <- function(name, val) {
        if(length == capacity) {
            methods$double.size()
        }

        length <<- length + 1
        buffer[[length]] <<- val
        names[length] <<- name
    }

    methods$as.list <- function() {
        b <- buffer[0:length]
        names(b) <- names[0:length]
        return(b)
    }

    methods
}

Benchmarks

Performance comparison using @phonetagger's code (which is based on @Cron Arconis' code). I have also added a better_env_as_container and changed the env_as_container_ a bit. The original env_as_container_ was broken and doesn't actually store all the numbers.

library(microbenchmark)
lPtrAppend <- function(lstptr, lab, obj) {lstptr[[deparse(lab)]] <- obj}
### Store list inside new environment
envAppendList <- function(lstptr, obj) {lstptr$list[[length(lstptr$list)+1]] <- obj} 
env2list <- function(env, len) {
    l <- vector('list', len)
    for (i in 1:len) {
        l[[i]] <- env[[as.character(i)]]
    }
    l
}
envl2list <- function(env, len) {
    l <- vector('list', len)
    for (i in 1:len) {
        l[[i]] <- env[[paste(as.character(i), 'L', sep='')]]
    }
    l
}
runBenchmark <- function(n) {
    microbenchmark(times = 5,  
        env_with_list_ = {
            listptr <- new.env(parent=globalenv())
            listptr$list <- NULL
            for(i in 1:n) {envAppendList(listptr, i)}
            listptr$list
        },
        c_ = {
            a <- list(0)
            for(i in 1:n) {a = c(a, list(i))}
        },
        list_ = {
            a <- list(0)
            for(i in 1:n) {a <- list(a, list(i))}
        },
        by_index = {
            a <- list(0)
            for(i in 1:n) {a[length(a) + 1] <- i}
            a
        },
        append_ = { 
            a <- list(0)    
            for(i in 1:n) {a <- append(a, i)} 
            a
        },
        env_as_container_ = {
            listptr <- new.env(hash=TRUE, parent=globalenv())
            for(i in 1:n) {lPtrAppend(listptr, i, i)} 
            envl2list(listptr, n)
        },
        better_env_as_container = {
            env <- new.env(hash=TRUE, parent=globalenv())
            for(i in 1:n) env[[as.character(i)]] <- i
            env2list(env, n)
        },
        linkedList = {
            a <- linkedList()
            for(i in 1:n) { a$add(i) }
            a$as.list()
        },
        inlineLinkedList = {
            a <- list()
            for(i in 1:n) { a <- list(a, i) }
            b <- vector('list', n)
            head <- a
            for(i in n:1) {
                b[[i]] <- head[[2]]
                head <- head[[1]]
            }                
        },
        expandingList = {
            a <- expandingList()
            for(i in 1:n) { a$add(i) }
            a$as.list()
        },
        inlineExpandingList = {
            l <- vector('list', 10)
            cap <- 10
            len <- 0
            for(i in 1:n) {
                if(len == cap) {
                    l <- c(l, vector('list', cap))
                    cap <- cap*2
                }
                len <- len + 1
                l[[len]] <- i
            }
            l[1:len]
        }
    )
}

# We need to repeatedly add an element to a list. With normal list concatenation
# or element setting this would lead to a large number of memory copies and a
# quadratic runtime. To prevent that, this function implements a bare bones
# expanding array, in which list appends are (amortized) constant time.
    expandingList <- function(capacity = 10) {
        buffer <- vector('list', capacity)
        length <- 0

        methods <- list()

        methods$double.size <- function() {
            buffer <<- c(buffer, vector('list', capacity))
            capacity <<- capacity * 2
        }

        methods$add <- function(val) {
            if(length == capacity) {
                methods$double.size()
            }

            length <<- length + 1
            buffer[[length]] <<- val
        }

        methods$as.list <- function() {
            b <- buffer[0:length]
            return(b)
        }

        methods
    }

    linkedList <- function() {
        head <- list(0)
        length <- 0

        methods <- list()

        methods$add <- function(val) {
            length <<- length + 1
            head <<- list(head, val)
        }

        methods$as.list <- function() {
            b <- vector('list', length)
            h <- head
            for(i in length:1) {
                b[[i]] <- head[[2]]
                head <- head[[1]]
            }
            return(b)
        }

        methods
    }

# We need to repeatedly add an element to a list. With normal list concatenation
# or element setting this would lead to a large number of memory copies and a
# quadratic runtime. To prevent that, this function implements a bare bones
# expanding array, in which list appends are (amortized) constant time.
    namedExpandingList <- function(capacity = 10) {
        buffer <- vector('list', capacity)
        names <- character(capacity)
        length <- 0

        methods <- list()

        methods$double.size <- function() {
            buffer <<- c(buffer, vector('list', capacity))
            names <<- c(names, character(capacity))
            capacity <<- capacity * 2
        }

        methods$add <- function(name, val) {
            if(length == capacity) {
                methods$double.size()
            }

            length <<- length + 1
            buffer[[length]] <<- val
            names[length] <<- name
        }

        methods$as.list <- function() {
            b <- buffer[0:length]
            names(b) <- names[0:length]
            return(b)
        }

        methods
    }

result:

> runBenchmark(1000)
Unit: microseconds
                    expr       min        lq      mean    median        uq       max neval
          env_with_list_  3128.291  3161.675  4466.726  3361.837  3362.885  9318.943     5
                      c_  3308.130  3465.830  6687.985  8578.913  8627.802  9459.252     5
                   list_   329.508   343.615   389.724   370.504   449.494   455.499     5
                by_index  3076.679  3256.588  5480.571  3395.919  8209.738  9463.931     5
                 append_  4292.321  4562.184  7911.882 10156.957 10202.773 10345.177     5
       env_as_container_ 24471.511 24795.849 25541.103 25486.362 26440.591 26511.200     5
 better_env_as_container  7671.338  7986.597  8118.163  8153.726  8335.659  8443.493     5
              linkedList  1700.754  1755.439  1829.442  1804.746  1898.752  1987.518     5
        inlineLinkedList  1109.764  1115.352  1163.751  1115.631  1206.843  1271.166     5
           expandingList  1422.440  1439.970  1486.288  1519.728  1524.268  1525.036     5
     inlineExpandingList   942.916   973.366  1002.461  1012.197  1017.784  1066.044     5
> runBenchmark(10000)
Unit: milliseconds
                    expr        min         lq       mean     median         uq        max neval
          env_with_list_ 357.760419 360.277117 433.810432 411.144799 479.090688 560.779139     5
                      c_ 685.477809 734.055635 761.689936 745.957553 778.330873 864.627811     5
                   list_   3.257356   3.454166   3.505653   3.524216   3.551454   3.741071     5
                by_index 445.977967 454.321797 515.453906 483.313516 560.374763 633.281485     5
                 append_ 610.777866 629.547539 681.145751 640.936898 760.570326 763.896124     5
       env_as_container_ 281.025606 290.028380 303.885130 308.594676 314.972570 324.804419     5
 better_env_as_container  83.944855  86.927458  90.098644  91.335853  92.459026  95.826030     5
              linkedList  19.612576  24.032285  24.229808  25.461429  25.819151  26.223597     5
        inlineLinkedList  11.126970  11.768524  12.216284  12.063529  12.392199  13.730200     5
           expandingList  14.735483  15.854536  15.764204  16.073485  16.075789  16.081726     5
     inlineExpandingList  10.618393  11.179351  13.275107  12.391780  14.747914  17.438096     5
> runBenchmark(20000)
Unit: milliseconds
                    expr         min          lq       mean      median          uq         max neval
          env_with_list_ 1723.899913 1915.003237 1921.23955 1938.734718 1951.649113 2076.910767     5
                      c_ 2759.769353 2768.992334 2810.40023 2820.129738 2832.350269 2870.759474     5
                   list_    6.112919    6.399964    6.63974    6.453252    6.910916    7.321647     5
                by_index 2163.585192 2194.892470 2292.61011 2209.889015 2436.620081 2458.063801     5
                 append_ 2832.504964 2872.559609 2983.17666 2992.634568 3004.625953 3213.558197     5
       env_as_container_  573.386166  588.448990  602.48829  597.645221  610.048314  642.912752     5
 better_env_as_container  154.180531  175.254307  180.26689  177.027204  188.642219  206.230191     5
              linkedList   38.401105   47.514506   46.61419   47.525192   48.677209   50.952958     5
        inlineLinkedList   25.172429   26.326681   32.33312   34.403442   34.469930   41.293126     5
           expandingList   30.776072   30.970438   34.45491   31.752790   38.062728   40.712542     5
     inlineExpandingList   21.309278   22.709159   24.64656   24.290694   25.764816   29.158849     5

I have added linkedList and expandingList and an inlined version of both. The inlinedLinkedList is basically a copy of list_, but it also converts the nested structure back into a plain list. Beyond that the difference between the inlined and non-inlined versions is due to the overhead of the function calls.

All variants of expandingList and linkedList show O(1) append performance, with the benchmark time scaling linearly with the number of items appended. linkedList is slower than expandingList, and the function call overhead is also visible. So if you really need all the speed you can get (and want to stick to R code), use an inlined version of expandingList.

I've also had a look at the C implementation of R, and both approaches should be O(1) append for any size up until you run out of memory.

I have also changed env_as_container_, the original version would store every item under index "i", overwriting the previously appended item. The better_env_as_container I have added is very similar to env_as_container_ but without the deparse stuff. Both exhibit O(1) performance, but they have an overhead that is quite a bit larger than the linked/expanding lists.

Memory overhead

In the C R implementation there is an overhead of 4 words and 2 ints per allocated object. The linkedList approach allocates one list of length two per append, for a total of (4*8+4+4+2*8=) 56 bytes per appended item on 64-bit computers (excluding memory allocation overhead, so probably closer to 64 bytes). The expandingList approach uses one word per appended item, plus a copy when doubling the vector length, so a total memory usage of up to 16 bytes per item. Since the memory is all in one or two objects the per-object overhead is insignificant. I haven't looked deeply into the env memory usage, but I think it will be closer to linkedList.

Python write line by line to a text file

Well, the problem you have is wrong line ending/encoding for notepad. Notepad uses Windows' line endings - \r\n and you use \n.

Save byte array to file

You can use:

File.WriteAllBytes("Foo.txt", arrBytes); // Requires System.IO

If you have an enumerable and not an array, you can use:

File.WriteAllBytes("Foo.txt", arrBytes.ToArray()); // Requires System.Linq

Case insensitive access for generic dictionary

Its not very elegant but in case you cant change the creation of dictionary, and all you need is a dirty hack, how about this:

var item = MyDictionary.Where(x => x.Key.ToLower() == MyIndex.ToLower()).FirstOrDefault();
    if (item != null)
    {
        TheValue = item.Value;
    }

In C#, what's the difference between \n and \r\n?

\n is the line break used by Unix(-like) systems, \r\n is used by windows. This has nothing to do with C#.

don't fail jenkins build if execute shell fails

The following works for mercurial by only committing if there are changes. So the build only fails if the commit fails.

hg id | grep "+" || exit 0
hg commit -m "scheduled commit"

Why powershell does not run Angular commands?

open windows powershell, run as administrater and SetExecution policy as Unrestricted then it will work.

Unit testing void methods?

Test its side-effects. This includes:

  • Does it throw any exceptions? (If it should, check that it does. If it shouldn't, try some corner cases which might if you're not careful - null arguments being the most obvious thing.)
  • Does it play nicely with its parameters? (If they're mutable, does it mutate them when it shouldn't and vice versa?)
  • Does it have the right effect on the state of the object/type you're calling it on?

Of course, there's a limit to how much you can test. You generally can't test with every possible input, for example. Test pragmatically - enough to give you confidence that your code is designed appropriately and implemented correctly, and enough to act as supplemental documentation for what a caller might expect.

Resetting a form in Angular 2 after submit

>= RC.6

Support resetting forms and maintain a submitted state.

console.log(this.form.submitted);
this.form.reset()

or

this.form = new FormGroup()...;

importat update

To set the Form controls to a state when the form is created, like validators, some additional measurements are necessary

In the view part of the form (html) add an *ngIf to show or hide the form

<form *ngIf="showForm"

In the component side of the form (*.ts) do this

  showForm:boolean = true;

  onSubmit(value:any):void {
    this.showForm = false;
    setTimeout(() => {
    this.reset()
      this.showForm = true;
    });
  }

Here is a more detailed example:

export class CreateParkingComponent implements OnInit {
  createParkingForm: FormGroup ;
  showForm = true ;

  constructor(
    private formBuilder: FormBuilder,
    private parkingService: ParkingService,
    private snackBar: MatSnackBar) {

      this.prepareForm() ;
  }

  prepareForm() {
    this.createParkingForm = this.formBuilder.group({
      'name': ['', Validators.compose([Validators.required, Validators.minLength(5)])],
      'company': ['', Validators.minLength(5)],
      'city': ['', Validators.required],
      'address': ['', Validators.compose([Validators.required, Validators.minLength(10)])],
      'latitude': [''],
      'longitude': [''],
      'phone': ['', Validators.compose([Validators.required, Validators.minLength(7)])],
      'pictureUrl': [''],
      // process the 3 input values of the maxCapacity'
      'pricingText': ['', Validators.compose([Validators.required, Validators.minLength(10)])],
      'ceilingType': ['', Validators.required],
    });
  }

  ngOnInit() {
  }


  resetForm(form: FormGroup) {
    this.prepareForm();
  }

  createParkingSubmit() {
    // Hide the form while the submit is done
    this.showForm = false ;

    // In this case call the backend and react to the success or fail answer

    this.parkingService.create(p).subscribe(
      response => {
        console.log(response);
        this.snackBar.open('Parqueadero creado', 'X', {duration: 3000});
        setTimeout(() => {
          //reset the form and show it again
          this.prepareForm();
            this.showForm = true;
          });
      }
      , error => {
        console.log(error);
        this.showForm = true ;
        this.snackBar.open('ERROR: al crear Parqueadero:' + error.message);
      }
      );
  }
}

Plunker example

original <= RC.5 Just move the code that creates the form to a method and call it again after you handled submit:

@Component({
  selector: 'form-component',
  template: `
    <form (ngSubmit)="onSubmit($event)" [ngFormModel]="form">
       <input type="test" ngControl="name">
       <input type="test" ngControl="email">
       <input type="test" ngControl="username">
       <button type="submit">submit</button>
    </form>
    <div>name: {{name.value}}</div>
    <div>email: {{email.value}}</div>
    <div>username: {{username.value}}</div>
`
})
class FormComponent {

  name:Control;
  username:Control;
  email:Control;

  form:ControlGroup;

  constructor(private builder:FormBuilder) {
    this.createForm();
  }

  createForm() {
    this.name = new Control('', Validators.required);
    this.email = new Control('', Validators.required);
    this.username = new Control('', Validators.required);

    this.form = this.builder.group({
      name: this.name,
      email: this.email,
      username: this.username
    });
  }

  onSubmit(value:any):void {
    // code that happens when form is submitted
    // then reset the form
    this.reset();
  }

  reset() {
    this.createForm();
  }
}

Plunker example