Programs & Examples On #Ie mobile

String comparison in Python: is vs. ==

See This question

Your logic in reading

For all built-in Python objects (like strings, lists, dicts, functions, etc.), if x is y, then x==y is also True.

is slightly flawed.

If is applies then == will be True, but it does NOT apply in reverse. == may yield True while is yields False.

MS Access DB Engine (32-bit) with Office 64-bit

Install the 2007 version, it seems that if you install the version opposite to the version of Office you are using you can make it work.

How to check if a string contains only numbers?

You could use a regular expression like this

If Regex.IsMatch(number, "^[0-9 ]+$") Then


End If

SSL handshake fails with - a verisign chain certificate - that contains two CA signed certificates and one self-signed certificate

Root certificates issued by CAs are just self-signed certificates (which may in turn be used to issue intermediate CA certificates). They have not much special about them, except that they've managed to be imported by default in many browsers or OS trust anchors.

While browsers and some tools are configured to look for the trusted CA certificates (some of which may be self-signed) in location by default, as far as I'm aware the openssl command isn't.

As such, any server that presents the full chain of certificate, from its end-entity certificate (the server's certificate) to the root CA certificate (possibly with intermediate CA certificates) will have a self-signed certificate in the chain: the root CA.

openssl s_client -connect -showcerts doesn't have any particular reason to trust Verisign's root CA certificate, and because it's self-signed you'll get "self signed certificate in certificate chain".

If your system has a location with a bundle of certificates trusted by default (I think /etc/pki/tls/certs on RedHat/Fedora and /etc/ssl/certs on Ubuntu/Debian), you can configure OpenSSL to use them as trust anchors, for example like this:

openssl s_client -connect -showcerts -CApath /etc/ssl/certs

How to calculate the bounding box for a given lat/lng location?

You're looking for an ellipsoid formula.

The best place I've found to start coding is based on the Geo::Ellipsoid library from CPAN. It gives you a baseline to create your tests off of and to compare your results with its results. I used it as the basis for a similar library for PHP at my previous employer.


Take a look at the location method. Call it twice and you've got your bbox.

You didn't post what language you were using. There may already be a geocoding library available for you.

Oh, and if you haven't figured it out by now, Google maps uses the WGS84 ellipsoid.

iFrame src change event detection?

If you have no control over the page and wish to watch for some kind of change then the modern method is to use MutationObserver

An example of its use, watching for the src attribute to change of an iframe

new MutationObserver(function(mutations) {_x000D_
  mutations.some(function(mutation) {_x000D_
    if (mutation.type === 'attributes' && mutation.attributeName === 'src') {_x000D_
      console.log('Old src: ', mutation.oldValue);_x000D_
      console.log('New src: ',;_x000D_
      return true;_x000D_
    return false;_x000D_
}).observe(document.body, {_x000D_
  attributes: true,_x000D_
  attributeFilter: ['src'],_x000D_
  attributeOldValue: true,_x000D_
  characterData: false,_x000D_
  characterDataOldValue: false,_x000D_
  childList: false,_x000D_
  subtree: true_x000D_
setTimeout(function() {_x000D_
  document.getElementsByTagName('iframe')[0].src = '';_x000D_
}, 3000);
<iframe src=""></iframe>

Output after 3 seconds

MutationRecord {oldValue: "", attributeNamespace: null, attributeName: "src", nextSibling: null, previousSibling: null…}
Old src:
New src: 

On jsFiddle

Posted answer here as original question was closed as a duplicate of this one.

Python json.loads shows ValueError: Extra data

I think saving dicts in a list is not an ideal solution here proposed by @falsetru.

Better way is, iterating through dicts and saving them to .json by adding a new line.

our 2 dictionaries are

d1 = {'a':1}

d2 = {'b':2}

you can write them to .json

import json
with open('sample.json','a') as sample:
    for dict in [d1,d2]:

and you can read json file without any issues

with open('sample.json','r') as sample:
    for line in sample:
        line = json.loads(line.strip())

simple and efficient

How to make RatingBar to show five stars

If you are wrapping the RatingBar inside a ConstraintLayout with match_constraint for its width, the editor preview is going to show a number of stars proportional to its actual width, no matter what if you set android:numStars property. Use wrap_content to get the correct preview:

<RatingBar android:id="@+id/myRatingBar"
           app:layout_constraintTop_toBottomOf="parent" />

How to parse a JSON Input stream

if you have JSON file you can set it on assets folder then call it using this code

InputStream in = mResources.getAssets().open("fragrances.json"); 
// where mResources object from Resources class

How to format date and time in Android?

Date format class work with cheat code to make date. Like

  1. M -> 7, MM -> 07, MMM -> Jul , MMMM -> July
  2. EEE -> Tue , EEEE -> Tuesday
  3. z -> EST , zzz -> EST , zzzz -> Eastern Standard Time

You can check more cheats here.

EOFError: end of file reached issue with Net::HTTP

After doing some research, this was happening in Ruby's XMLRPC::Client library - which uses NET::HTTP. The client uses the start() method in NET::HTTP which keeps the connection open for future requests.

This happened precisely at 30 seconds after the last requests - so my assumption here is that the server it's hitting is closing requests after that time. I'm not sure what the default is for NET::HTTP to keep the request open - but I'm about to test with 60 seconds to see if that solves the issue.

Trigger css hover with JS

You can't. It's not a trusted event.

Events that are generated by the user agent, either as a result of user interaction, or as a direct result of changes to the DOM, are trusted by the user agent with privileges that are not afforded to events generated by script through the DocumentEvent.createEvent("Event") method, modified using the Event.initEvent() method, or dispatched via the EventTarget.dispatchEvent() method. The isTrusted attribute of trusted events has a value of true, while untrusted events have a isTrusted attribute value of false.

Most untrusted events should not trigger default actions, with the exception of click or DOMActivate events.

You have to add a class and add/remove that on the mouseover/mouseout events manually.

Side note, I'm answering this here after I marked this as a duplicate since no answer here really covers the issue from what I see. Hopefully, one day it'll be merged.

Using Chrome, how to find to which events are bound to an element

(Latest as of 2020) For version Chrome Version 83.0.4103.61 :

Chrome Developer Tools - Event Listener

  1. Select the element you want to inspect

  2. Choose the Event Listeners tab

  3. Make sure to check the Framework listeners to show the real javascript file instead of the jquery function.

EOFError: EOF when reading a line

convert your inputs to ints:

width = int(input())
height = int(input())

Seaborn plots not showing up

I come to this question quite regularly and it always takes me a while to find what I search:

import seaborn as sns
import matplotlib.pyplot as plt  # <--- This is what you are looking for

Please note: In Python 2, you can also use, but not in Python 3.

Complete Example

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""Visualize C_0.99 for all languages except the 10 with most characters."""

import seaborn as sns
import matplotlib.pyplot as plt

l = [41, 44, 46, 46, 47, 47, 48, 48, 49, 51, 52, 53, 53, 53, 53, 55, 55, 55,
     55, 56, 56, 56, 56, 56, 56, 57, 57, 57, 57, 57, 57, 57, 57, 58, 58, 58,
     58, 59, 59, 59, 59, 59, 59, 59, 59, 60, 60, 60, 60, 60, 60, 60, 60, 61,
     61, 61, 61, 61, 61, 61, 61, 61, 61, 61, 62, 62, 62, 62, 62, 62, 62, 62,
     62, 63, 63, 63, 63, 63, 63, 63, 63, 63, 64, 64, 64, 64, 64, 64, 64, 65,
     65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 66, 66, 66, 66, 66, 66, 66,
     67, 67, 67, 67, 67, 67, 67, 67, 68, 68, 68, 68, 68, 69, 69, 69, 70, 70,
     70, 70, 71, 71, 71, 71, 71, 72, 72, 72, 72, 73, 73, 73, 73, 73, 73, 73,
     74, 74, 74, 74, 74, 75, 75, 75, 76, 77, 77, 78, 78, 79, 79, 79, 79, 80,
     80, 80, 80, 81, 81, 81, 81, 83, 84, 84, 85, 86, 86, 86, 86, 87, 87, 87,
     87, 87, 88, 90, 90, 90, 90, 90, 90, 91, 91, 91, 91, 91, 91, 91, 91, 92,
     92, 93, 93, 93, 94, 95, 95, 96, 98, 98, 99, 100, 102, 104, 105, 107, 108,
     109, 110, 110, 113, 113, 115, 116, 118, 119, 121]

sns.distplot(l, kde=True, rug=False)


enter image description here

Javascript | Set all values of an array

map is the most logical solution for this problem.

let xs = [1, 2, 3];
xs = => 42);
xs // -> [42, 42, 42]

However, if there is a chance that the array is sparse, you'll need to use for or, even better, for .. of.


Rotate a div using javascript

I recently had to build something similar. You can check it out in the snippet below.

The version I had to build uses the same button to start and stop the spinner, but you can manipulate to code if you have a button to start the spin and a different button to stop the spin

Basically, my code looks like this...

Run Code Snippet

var rocket = document.querySelector('.rocket');_x000D_
var btn = document.querySelector('.toggle');_x000D_
var rotate = false;_x000D_
var runner;_x000D_
var degrees = 0;_x000D_
function start(){_x000D_
    runner = setInterval(function(){_x000D_
        degrees++;_x000D_ = 'rotate(' + degrees + 'deg)';_x000D_
function stop(){_x000D_
btn.addEventListener('click', function(){_x000D_
    if (!rotate){_x000D_
        rotate = true;_x000D_
    } else {_x000D_
        rotate = false;_x000D_
body {_x000D_
  background: #1e1e1e;_x000D_
}    _x000D_
.rocket {_x000D_
    width: 150px;_x000D_
    height: 150px;_x000D_
    margin: 1em;_x000D_
    border: 3px dashed teal;_x000D_
    border-radius: 50%;_x000D_
    background-color: rgba(128,128,128,0.5);_x000D_
    display: flex;_x000D_
    justify-content: center;_x000D_
    align-items: center;_x000D_
  .rocket h1 {_x000D_
    margin: 0;_x000D_
    padding: 0;_x000D_
    font-size: .8em;_x000D_
    color: skyblue;_x000D_
    letter-spacing: 1em;_x000D_
    text-shadow: 0 0 10px black;_x000D_
  .toggle {_x000D_
    margin: 10px;_x000D_
    background: #000;_x000D_
    color: white;_x000D_
    font-size: 1em;_x000D_
    padding: .3em;_x000D_
    border: 2px solid red;_x000D_
    outline: none;_x000D_
    letter-spacing: 3px;_x000D_
<div class="rocket"><h1>SPIN ME</h1></div>_x000D_
<button class="toggle">I/0</button>

How to loop over grouped Pandas dataframe?

Here is an example of iterating over a pd.DataFrame grouped by the column atable. For this sample, "create" statements for an SQL database are generated within the for loop:

import pandas as pd

df1 = pd.DataFrame({
    'atable':     ['Users', 'Users', 'Domains', 'Domains', 'Locks'],
    'column':     ['col_1', 'col_2', 'col_a', 'col_b', 'col'],
    'column_type':['varchar', 'varchar', 'int', 'varchar', 'varchar'],
    'is_null':    ['No', 'No', 'Yes', 'No', 'Yes'],

df1_grouped = df1.groupby('atable')

# iterate over each group
for group_name, df_group in df1_grouped:
    print('\nCREATE TABLE {}('.format(group_name))

    for row_index, row in df_group.iterrows():
        col = row['column']
        column_type = row['column_type']
        is_null = 'NOT NULL' if row['is_null'] == 'NO' else ''
        print('\t{} {} {},'.format(col, column_type, is_null))


How to suspend/resume a process in Windows?

I use (a very old) process explorer from SysInternals (procexp.exe). It is a replacement / addition to the standard Task manager, you can suspend a process from there.

Edit: Microsoft has bought over SysInternals, url: procExp.exe

Other than that you can set the process priority to low so that it does not get in the way of other processes, but this will not suspend the process.

Pagination response payload from a RESTful API

ReSTful APIs are consumed primarily by other systems, which is why I put paging data in the response headers. However, some API consumers may not have direct access to the response headers, or may be building a UX over your API, so providing a way to retrieve (on demand) the metadata in the JSON response is a plus.

I believe your implementation should include machine-readable metadata as a default, and human-readable metadata when requested. The human-readable metadata could be returned with every request if you like or, preferably, on-demand via a query parameter, such as include=metadata or include_metadata=true.

In your particular scenario, I would include the URI for each product with the record. This makes it easy for the API consumer to create links to the individual products. I would also set some reasonable expectations as per the limits of my paging requests. Implementing and documenting default settings for page size is an acceptable practice. For example, GitHub's API sets the default page size to 30 records with a maximum of 100, plus sets a rate limit on the number of times you can query the API. If your API has a default page size, then the query string can just specify the page index.

In the human-readable scenario, when navigating to /products?page=5&per_page=20&include=metadata, the response could be:

      "page": 5,
      "per_page": 20,
      "page_count": 20,
      "total_count": 521,
      "Links": [
        {"self": "/products?page=5&per_page=20"},
        {"first": "/products?page=0&per_page=20"},
        {"previous": "/products?page=4&per_page=20"},
        {"next": "/products?page=6&per_page=20"},
        {"last": "/products?page=26&per_page=20"},
  "records": [
      "id": 1,
      "name": "Widget #1",
      "uri": "/products/1"
      "id": 2,
      "name": "Widget #2",
      "uri": "/products/2"
      "id": 3,
      "name": "Widget #3",
      "uri": "/products/3"

For machine-readable metadata, I would add Link headers to the response:

Link: </products?page=5&perPage=20>;rel=self,</products?page=0&perPage=20>;rel=first,</products?page=4&perPage=20>;rel=previous,</products?page=6&perPage=20>;rel=next,</products?page=26&perPage=20>;rel=last

(the Link header value should be urlencoded)

...and possibly a custom total-count response header, if you so choose:

total-count: 521

The other paging data revealed in the human-centric metadata might be superfluous for machine-centric metadata, as the link headers let me know which page I am on and the number per page, and I can quickly retrieve the number of records in the array. Therefore, I would probably only create a header for the total count. You can always change your mind later and add more metadata.

As an aside, you may notice I removed /index from your URI. A generally accepted convention is to have your ReST endpoint expose collections. Having /index at the end muddies that up slightly.

These are just a few things I like to have when consuming/creating an API. Hope that helps!

C# 4.0 optional out/ref arguments

What about like this?

public bool OptionalOutParamMethod([Optional] ref string pOutParam)
    return true;

You still have to pass a value to the parameter from C# but it is an optional ref param. is not a function

data is not an array, it is an object with an array of products so iterate over data.products

var allProducts = (item) {
    return new getData(item);

Log4j2 configuration - No log4j2 configuration file found

Additionally to what Tomasz W wrote, by starting your application you could use settings:


to get most of configuration problems.

For details see Log4j2 FAQ: How do I debug my configuration?

Conversion failed when converting the varchar value to data type int in sql

The problem located on the following line

SELECT  @Prefix + LEN(CAST(@maxCode AS VARCHAR(10))+1) + CAST(@maxCode AS VARCHAR(100))

Use this instead

SELECT  @Prefix + CAST(LEN(CAST(@maxCode AS VARCHAR(10))+1) AS VARCHAR(100)) + CAST(@maxCode AS VARCHAR(100))

Full Code:

CREATE PROC [dbo].[getVoucherNo]



    DECLARE @Prefix VARCHAR(10)='J'

    DECLARE @startFrom INT=1

    DECLARE @maxCode VARCHAR(100)

    DECLARE @sCode INT

    IF((SELECT COUNT(*) FROM dbo.Journal_Entry) > 0)
        SELECT @maxCode = CAST(MAX(CAST(SUBSTRING(VoucharNo,LEN(@startFrom)+1,LEN(VoucharNo)- LEN(@Prefix)) AS INT))+1 AS varchar(100)) FROM dbo.Journal_Entry;
        SET @sCode=CAST(@maxCode AS INT)
        SELECT  @Prefix + CAST(LEN(CAST(@maxCode AS VARCHAR(10))+1) AS VARCHAR(100)) + CAST(@maxCode AS VARCHAR(100))
        SELECT(@Prefix + CAST(@startFrom AS VARCHAR)) 

Group query results by month and year in postgresql

bma answer is great! I have used it with ActiveRecords, here it is if anybody needs it in Rails:

  "SELECT TO_CHAR(created_at, 'Mon') AS month,
   EXTRACT(year from created_at) as year,
   SUM(desired_value) as desired_value
   FROM desired_table
   GROUP BY 1,2
   ORDER BY 1,2"

if statements matching multiple values

Easier is subjective, but maybe the switch statement would be easier? You don't have to repeat the variable, so more values can fit on the line, and a line with many comparisons is more legible than the counterpart using the if statement.

When to use RSpec let()?

I always prefer let to an instance variable for a couple of reasons:

  • Instance variables spring into existence when referenced. This means that if you fat finger the spelling of the instance variable, a new one will be created and initialized to nil, which can lead to subtle bugs and false positives. Since let creates a method, you'll get a NameError when you misspell it, which I find preferable. It makes it easier to refactor specs, too.
  • A before(:each) hook will run before each example, even if the example doesn't use any of the instance variables defined in the hook. This isn't usually a big deal, but if the setup of the instance variable takes a long time, then you're wasting cycles. For the method defined by let, the initialization code only runs if the example calls it.
  • You can refactor from a local variable in an example directly into a let without changing the referencing syntax in the example. If you refactor to an instance variable, you have to change how you reference the object in the example (e.g. add an @).
  • This is a bit subjective, but as Mike Lewis pointed out, I think it makes the spec easier to read. I like the organization of defining all my dependent objects with let and keeping my it block nice and short.

A related link can be found here:

Table scroll with HTML and CSS

Works only in Chrome but it can be adapted to other modern browsers. Table falls back to common table with scroll bar in other brws. Uses CSS3 FLEX property.

<table border="1px" class="flexy">
    <caption>Lista Sumnjivih vozila:</caption>
            <td>Opis Sumnje</td>
        <td>Registarski<br>broj vozila</td>

        <td>Osumnjicen tranzit</td>
        <td>23-03-2014 20:48:08</td>
        <td>Raskrsnica kod pumpe<br></td>

        <td>Osumnjicen tranzit</td>
        <td>23-03-2014 20:48:08</td>
        <td>Raskrsnica kod pumpe<br></td>

        <td>Osumnjicen tranzit</td>
        <td>23-03-2014 20:48:08</td>
        <td>Raskrsnica kod pumpe<br></td>

        <td>Osumnjicen tranzit</td>
        <td>23-03-2014 20:48:08</td>
        <td>Raskrsnica kod pumpe<br></td>


Style (CSS 3):

caption {
    display: block;
    line-height: 3em;
    width: 100%;
    -webkit-align-items: stretch;
    border: 1px solid #eee;

       .flexy {
            display: block;
            width: 90%;
            border: 1px solid #eee;
            max-height: 320px;
            overflow: auto;

        .flexy thead {
            display: -webkit-flex;
            -webkit-flex-flow: row;

        .flexy thead tr {
            padding-right: 15px;
            display: -webkit-flex;
            width: 100%;
            -webkit-align-items: stretch;

        .flexy tbody {
            display: -webkit-flex;
            height: 100px;
            overflow: auto;
            -webkit-flex-flow: row wrap;
        .flexy tbody tr{
            display: -webkit-flex;
            width: 100%;

        .flexy tr td {
            width: 15%;

Save PHP variables to a text file

for_example, you have anyFile.php, and there is written $any_variable='hi Frank';

to change that variable to hi Jack, use like the following code:

$content = file_get_contents('anyFile.php'); 

$new_content = preg_replace('/\$any_variable=\"(.*?)\";/', '$any_variable="hi Jack";', $content);

file_put_contents('anyFile.php', $new_content);

Run task only if host does not belong to a group

Here's another way to do this:

- name: my command
  command: echo stuff
  when: "'groupname' not in group_names"

group_names is a magic variable as documented here: :

group_names is a list (array) of all the groups the current host is in.

Find and Replace Inside a Text File from a Bash Command

You can use rpl command. For example you want to change domain name in whole php project.

rpl -ivRpd -x'.php' '' '' ./path_to_your_project_folder/  

This is not clear bash of cause, but it's a very quick and usefull. :)

Android: textview hyperlink


    android:text="" />

This flag


controls whether links such as urls automatically found and converted to clickable links. The default value is "none", disabling this feature. Values: all, email, map, none, phone, web.

change cursor to finger pointer

<a class="menu_links" onclick="displayData(11,1,0,'A')" onmouseover="" style="cursor: pointer;"> A </a>

It's css.

Or in a style sheet:

a.menu_links { cursor: pointer; }

ASP.NET Core Get Json Array using IConfiguration

public class MyArray : List<string> { }


public SomeController(IOptions<MyArray> myArrayOptions)
    myArray = myArrayOptions.Value;

Uses of content-disposition in an HTTP response header

Refer to RFC 6266 (Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP))

Create multiple threads and wait all of them to complete

Most proposed answers don't take into account a time-out interval, which is very important to prevent a possible deadlock. Next is my sample code. (Note that I'm primarily a Win32 developer, and that's how I'd do it there.)

//'arrRunningThreads' = List<Thread>

//Wait for all threads
const int knmsMaxWait = 3 * 1000;           //3 sec timeout
int nmsBeginTicks = Environment.TickCount;
foreach(Thread thrd in arrRunningThreads)
    //See time left
    int nmsElapsed = Environment.TickCount - nmsBeginTicks;
    int nmsRemain = knmsMaxWait - nmsElapsed;
    if(nmsRemain < 0)
        nmsRemain = 0;

    //Then wait for thread to exit
        //It didn't exit in time, terminate it

        //Issue a debugger warning
        Debug.Assert(false, "Terminated thread");

How to deploy a React App on Apache web server

As said in the post, React is a browser based technology. It only renders a view in an HTML document.

To be able to have access to your "React App", you need to:

  1. Bundle your React app in a bundle
  2. Have Apache pointing to your html file in your server, and allowing access externally.

You might have all the informations here: for the Apache server, and here to make your javascript bundle

Detect if range is empty

IsEmpty returns True if the variable is uninitialized, or is explicitly set to Empty; otherwise, it returns False. False is always returned if expression contains more than one variable. IsEmpty only returns meaningful information for variants. ( . So you must check every cell in range separately:

    Dim thisColumn as Byte, thisRow as Byte

    For thisColumn = 1 To 5
        For ThisRow = 1 To 6
             If IsEmpty(Cells(thisRow, thisColumn)) = False Then
                 GoTo RangeIsNotEmpty
             End If
        Next thisRow
    Next thisColumn

Of course here are more code than in solution with CountA function which count not empty cells, but GoTo can interupt loops if at least one not empty cell is found and do your code faster especially if range is large and you need to detect this case. Also this code for me is easier to understand what it is doing, than with Excel CountA function which is not VBA function.

iOS 7 - Failing to instantiate default view controller

None of the above solved the issue for me. In my case it was not also setting the correct application scene manifest.

I had to change LoginScreen used to be Main

enter image description here

AlertDialog styling - how to change style (color) of title, message, etc

Use this in your Style in your values-v21/style.xml

<style name="AlertDialogCustom" parent="@android:style/Theme.Material.Dialog.NoActionBar">_x000D_
        <item name="android:windowBackground">@android:color/white</item>_x000D_
        <item name="android:windowActionBar">false</item>_x000D_
        <item name="android:colorAccent">@color/cbt_ui_primary_dark</item>_x000D_
        <item name="android:windowTitleStyle">@style/DialogWindowTitle.Sphinx</item>_x000D_
        <item name="android:textColorPrimary">@color/cbt_hints_color</item>_x000D_
        <item name="android:backgroundDimEnabled">true</item>_x000D_
        <item name="android:windowMinWidthMajor">@android:dimen/dialog_min_width_major</item>_x000D_
        <item name="android:windowMinWidthMinor">@android:dimen/dialog_min_width_minor</item>_x000D_

And for pre lollipop devices put it in values/style.xml

<style name="AlertDialogCustom" parent="@android:style/Theme.Material.Dialog.NoActionBar">_x000D_
        <item name="android:windowBackground">@android:color/white</item>_x000D_
        <item name="android:windowActionBar">false</item>_x000D_
        <item name="android:colorAccent">@color/cbt_ui_primary_dark</item>_x000D_
        <item name="android:windowTitleStyle">@style/DialogWindowTitle.Sphinx</item>_x000D_
        <item name="android:textColorPrimary">@color/cbt_hints_color</item>_x000D_
        <item name="android:backgroundDimEnabled">true</item>_x000D_
        <item name="android:windowMinWidthMajor">@android:dimen/dialog_min_width_major</item>_x000D_
        <item name="android:windowMinWidthMinor">@android:dimen/dialog_min_width_minor</item>_x000D_
<style name="DialogWindowTitle.Sphinx" parent="@style/DialogWindowTitle_Holo">_x000D_
       <item name="android:textAppearance">@style/TextAppearance.Sphinx.DialogWindowTitle</item>_x000D_
<style name="TextAppearance.Sphinx.DialogWindowTitle" parent="@android:style/TextAppearance.Holo.DialogWindowTitle">_x000D_
        <item name="android:textColor">@color/dark</item>_x000D_
        <!--<item name="android:fontFamily">sans-serif-condensed</item>-->_x000D_
        <item name="android:textStyle">bold</item>_x000D_

Deleting an object in C++

Isn't this the normal way to free the memory associated with an object?

This is a common way of managing dynamically allocated memory, but it's not a good way to do so. This sort of code is brittle because it is not exception-safe: if an exception is thrown between when you create the object and when you delete it, you will leak that object.

It is far better to use a smart pointer container, which you can use to get scope-bound resource management (it's more commonly called resource acquisition is initialization, or RAII).

As an example of automatic resource management:

void test()
    std::auto_ptr<Object1> obj1(new Object1);

} // The object is automatically deleted when the scope ends.

Depending on your use case, auto_ptr might not provide the semantics you need. In that case, you can consider using shared_ptr.

As for why your program crashes when you delete the object, you have not given sufficient code for anyone to be able to answer that question with any certainty.

How to ignore HTML element from tabindex?

Such hack like "tabIndex=-1" not work for me with Chrome v53.

This is which works for chrome, and most browsers:

function removeTabIndex(element) {_x000D_
<input tabIndex="1" />_x000D_
<input tabIndex="2" id="notabindex" />_x000D_
<input tabIndex="3" />_x000D_
<button tabIndex="4" onclick="removeTabIndex(document.getElementById('notabindex'))">Remove tabindex</button>

Rolling or sliding window iterator?

Trying my part, simple, one liner, pythonic way using islice. But, may not be optimally efficient.

from itertools import islice
array = range(0, 10)
window_size = 4
map(lambda i: list(islice(array, i, i + window_size)), range(0, len(array) - window_size + 1))
# output = [[0, 1, 2, 3], [1, 2, 3, 4], [2, 3, 4, 5], [3, 4, 5, 6], [4, 5, 6, 7], [5, 6, 7, 8], [6, 7, 8, 9]]

Explanation: Create window by using islice of window_size and iterate this operation using map over all array.

How to pass text in a textbox to JavaScript function?

You can get textbox value and Id by the following simple example in dotNet programming

         <script type="text/javascript">
             function GetTextboxId_Value(textBox) 
                 alert(textBox.value);    // To get Text Box Value(Text)
                 alert(;      // To get Text Box Id like txtSearch
 <input id="txtSearch" type="text" onkeyup="GetTextboxId_Value(this)" />  </body>

How do I use JDK 7 on Mac OSX?

The instructions by peter_budo worked perfectly. I had to add the jars under /Library/Java/JavaVirtualMachines/JDK 1.7.0 Developer Preview.jdk/Contents/Home/jre/lib/ to my IntelliJ project libraries. Now it works like a charm. Note that I didn't need my IDE itself to run under 1.7; rather, I only needed to be able to compile and run against 1.7. I'll most likely continue to use Apple's JRE for running the IDE since it's probably more stable with respect to graphics routines (Swing, AWT). Like the OP, I was really keen on testing out the new NIO2 API. Looking good so far. Thanks, Peter.

Convert char array to string use C

You're saying you have this:

char array[20]; char string[100];

And you'd like to have this:

string[0]= "178.9"; // where it was stored 178.9 position [0]

You can't have that. A char holds 1 character. That's it. A "string" in C is an array of characters followed by a sentinel character (NULL terminator).

Now if you want to copy the first x characters out of array to string you can do that with memcpy():

memcpy(string, array, x);
string[x] = '\0'; 

Is there a REAL performance difference between INT and VARCHAR primary keys?

At HauteLook, we changed many of our tables to use natural keys. We did experience a real-world increase in performance. As you mention, many of our queries now use less joins which makes the queries more performant. We will even use a composite primary key if it makes sense. That being said, some tables are just easier to work with if they have a surrogate key.

Also, if you are letting people write interfaces to your database, a surrogate key can be helpful. The 3rd party can rely on the fact that the surrogate key will change only in very rare circumstances.

nginx: send all requests to a single html page

Using just try_files didn't work for me - it caused a rewrite or internal redirection cycle error in my logs.

The Nginx docs had some additional details:

So I ended up using the following:

root /var/www/mysite;

location / {
    try_files $uri /base.html;

location = /base.html {
    expires 30s;

Add numpy array as column to Pandas data frame

Consider using a higher dimensional datastructure (a Panel), rather than storing an array in your column:

In [11]: p = pd.Panel({'df': df, 'csc': csc})

In [12]: p.df
   0  1  2
0  1  2  3
1  4  5  6
2  7  8  9

In [13]:
   0  1  2
0  0  1  0
1  0  0  1
2  1  0  0

Look at cross-sections etc, etc, etc.

In [14]: p.xs(0)
   csc  df
0    0   1
1    1   2
2    0   3

See the docs for more on Panels.

How to stretch the background image to fill a div

For this you can use CSS3 background-size property. Write like this:

    -moz-background-size:100% 100%;
    -webkit-background-size:100% 100%;
    background-size:100% 100%;
    border: 1px solid red;

Check this:

How to decrypt Hash Password in Laravel

Short answer is that you don't 'decrypt' the password (because it's not encrypted - it's hashed).

The long answer is that you shouldn't send the user their password by email, or any other way. If the user has forgotten their password, you should send them a password reset email, and allow them to change their password on your website.

Laravel has most of this functionality built in (see the Laravel documentation - I'm not going to replicate it all here. Also available for versions 4.2 and 5.0 of Laravel).

For further reading, check out this 'blogoverflow' post: Why passwords should be hashed.

HTTPS setup in Amazon EC2

One of the best resources I found was using let's encrypt, you do not need ELB nor cloudfront for your EC2 instance to have HTTPS, just follow the following simple instructions: let's encrypt Login to your server and follow the steps in the link.

It is also important as mentioned by others that you have port 443 opened by editing your security groups

You can view your certificate or any other website's by changing the site name in this link

Please do not forget that it is only valid for 90 days

Webclient / HttpWebRequest with Basic Authentication returns 404 not found for valid URL

This part of code worked fine for me:

        WebRequest request = WebRequest.Create(url);
        request.Method = WebRequestMethods.Http.Get;
        NetworkCredential networkCredential = new NetworkCredential(logon, password); // logon in format "domain\username"
        CredentialCache myCredentialCache = new CredentialCache {{new Uri(url), "Basic", networkCredential}};
        request.PreAuthenticate = true;
        request.Credentials = myCredentialCache;
        using (WebResponse response = request.GetResponse())

            using (Stream dataStream = response.GetResponseStream())
                using (StreamReader reader = new StreamReader(dataStream))
                    string responseFromServer = reader.ReadToEnd();

How to scroll page in flutter

You can use this one and it's best practice.

  child: Column(
    children: <Widget>[
      //Your Widgets
      //Your Widgets,
      //Your Widgets

How to compare two object variables in EL expression language?

In Expression Language you can just use the == or eq operator to compare object values. Behind the scenes they will actually use the Object#equals(). This way is done so, because until with the current EL 2.1 version you cannot invoke methods with other signatures than standard getter (and setter) methods (in the upcoming EL 2.2 it would be possible).

So the particular line

<c:when test="${lang}.equals(${pageLang})">

should be written as (note that the whole expression is inside the { and })

<c:when test="${lang == pageLang}">

or, equivalently

<c:when test="${lang eq pageLang}">

Both are behind the scenes roughly interpreted as


If you want to compare constant String values, then you need to quote it

<c:when test="${lang == 'en'}">

or, equivalently

<c:when test="${lang eq 'en'}">

which is behind the scenes roughly interpreted as


Java enum - why use toString instead of name

name() is literally the textual name in the java code of the enum. That means it is limited to strings that can actually appear in your java code, but not all desirable strings are expressible in code. For example, you may need a string that begins with a number. name() will never be able to obtain that string for you.

Determine what user created objects in SQL Server

The answer is "no, you probably can't".

While there is stuff in there that might say who created a given object, there are a lot of "ifs" behind them. A quick (and not necessarily complete) review:

sys.objects (and thus sys.tables, sys.procedures, sys.views, etc.) has column principal_id. This value is a foreign key that relates to the list of database users, which in turn can be joined with the list of SQL (instance) logins. (All of this info can be found in further system views.)


A quick check on our setup here and a cursory review of BOL indicates that this value is only set (i.e. not null) if it is "different from the schema owner". In our development system, and we've got dbo + two other schemas, everything comes up as NULL. This is probably because everyone has dbo rights within these databases.

This is using NT authentication. SQL authentication probably works much the same. Also, does everyone have and use a unique login, or are they shared? If you have employee turnover and domain (or SQL) logins get dropped, once again the data may not be there or may be incomplete.

You can look this data over (select * from sys.objects), but if principal_id is null, you are probably out of luck.

Java compiler level does not match the version of the installed Java project facet

I resolved it by Myproject--->java Resource---->libraries-->JRE System Libraries[java-1.6] click on this go to its "property" select "Classpath Container" change the Execution Environment to java-1.8(jdk1.8.0-35) (that is latest)

Change the jdk to latest

How to specify the JDK version in android studio?

For new Android Studio versions, go to C:\Program Files\Android\Android Studio\jre\bin(or to location of Android Studio installed files) and open command window at this location and type in following command in command prompt:-

java -version

ARG or ENV, which one to use in this case?

So if want to set the value of an environment variable to something different for every build then we can pass these values during build time and we don't need to change our docker file every time.

While ENV, once set cannot be overwritten through command line values. So, if we want to have our environment variable to have different values for different builds then we could use ARG and set default values in our docker file. And when we want to overwrite these values then we can do so using --build-args at every build without changing our docker file.

For more details, you can refer this.

-bash: syntax error near unexpected token `newline'

The characters '<', and '>', are to indicate a place-holder, you should remove them to read:

php /usr/local/solusvm/scripts/pass.php --type=admin --comm=change --username=ADMINUSERNAME

How do I measure request and response times at once using cURL?

Hey is better than Apache Bench, has fewer issues with SSL

./hey -more
  Total:    3.0960 secs
  Slowest:  1.6052 secs
  Fastest:  0.4063 secs
  Average:  0.6773 secs
  Requests/sec: 64.5992

Response time histogram:
  0.406 [1] |
  0.526 [142]   |????????????????????????????????????????
  0.646 [1] |
  0.766 [6] |??
  0.886 [0] |
  1.006 [0] |
  1.126 [0] |
  1.246 [12]    |???
  1.365 [32]    |?????????
  1.485 [5] |?
  1.605 [1] |

Latency distribution:
  10% in 0.4265 secs
  25% in 0.4505 secs
  50% in 0.4838 secs
  75% in 1.2181 secs
  90% in 1.2869 secs
  95% in 1.3384 secs
  99% in 1.4085 secs

Details (average, fastest, slowest):
  DNS+dialup:    0.1150 secs, 0.0000 secs, 0.4849 secs
  DNS-lookup:    0.0032 secs, 0.0000 secs, 0.0319 secs
  req write:     0.0001 secs, 0.0000 secs, 0.0007 secs
  resp wait:     0.2068 secs, 0.1690 secs, 0.4906 secs
  resp read:     0.0117 secs, 0.0011 secs, 0.2375 secs

Status code distribution:
  [200] 200 responses


What is a Memory Heap?

You probably mean heap memory, not memory heap.

Heap memory is essentially a large pool of memory (typically per process) from which the running program can request chunks. This is typically called dynamic allocation.

It is different from the Stack, where "automatic variables" are allocated. So, for example, when you define in a C function a pointer variable, enough space to hold a memory address is allocated on the stack. However, you will often need to dynamically allocate space (With malloc) on the heap and then provide the address where this memory chunk starts to the pointer.

What is a provisioning profile used for when developing iPhone applications?

A Quote from : iPhone Developer Program (~8MB PDF)

A provisioning profile is a collection of digital entities that uniquely ties developers and devices to an authorized iPhone Development Team and enables a device to be used for testing. A Development Provisioning Profile must be installed on each device on which you wish to run your application code. Each Development Provisioning Profile will contain a set of iPhone Development Certificates, Unique Device Identifiers and an App ID. Devices specified within the provisioning profile can be used for testing only by those individuals whose iPhone Development Certificates are included in the profile. A single device can contain multiple provisioning profiles.

How to print values separated by spaces instead of new lines in Python 2.7

This does almost everything you want:

f = open('data.txt', 'rb')

while True:
    char =
    if not char: break
    print "{:02x}".format(ord(char)),

With data.txt created like this:

f = open('data.txt', 'wb')

I get the following output:

61 62 0d 0a 63 64

tl;dr -- 1. You are using poor variable names. 2. You are slicing your hex strings incorrectly. 3. Your code is never going to replace any newlines. You may just want to forget about that feature. You do not quite yet understand the difference between a character, its integer code, and the hex string that represents the integer. They are all different: two are strings and one is an integer, and none of them are equal to each other. 4. For some files, you shouldn't remove newlines.


1. Your variable names are horrendous.

That's fine if you never want to ask anybody questions. But since every one needs to ask questions, you need to use descriptive variable names that anyone can understand. Your variable names are only slightly better than these:

fname = 'data.txt'
f = open(fname, 'rb')
xxxyxx =

xxyxxx = len(xxxyxx)
print "Length of file is", xxyxxx, "bytes. "
yxxxxx = 0

while yxxxxx < xxyxxx:
    xyxxxx = hex(ord(xxxyxx[yxxxxx]))
    xyxxxx = xyxxxx[-2:]
    yxxxxx = yxxxxx + 1
    xxxxxy = chr(13) + chr(10)
    xxxxyx = str(xxxxxy)
    xyxxxxx = str(xyxxxx)
    xyxxxxx.replace(xxxxyx, ' ')
    print xyxxxxx

That program runs fine, but it is impossible to understand.

2. The hex() function produces strings of different lengths.

For instance,

print hex(61)
print hex(15)


And taking the slice [-2:] for each of those strings gives you:


See how you got the 'x' in the second one? The slice:


says to go to the end of the string and back up two characters, then grab the rest of the string. Instead of doing that, take the slice starting 3 characters in from the beginning:


3. Your code will never replace any newlines.

Suppose your file has these two consecutive characters:


Now you read in the first character, "\r", and convert it to an integer, ord("\r"), giving you the integer 13. Now you convert that to a string, hex(13), which gives you the string "0xd", and you slice off the first two characters giving you:


Next, this line in your code:

bndtx.replace(entx, ' ')

tries to find every occurrence of the string "\r\n" in the string "d" and replace it. There is never going to be any replacement because the replacement string is two characters long and the string "d" is one character long.

The replacement won't work for "\r\n" and "0d" either. But at least now there is a possibility it could work because both strings have two characters. Let's reduce both strings to a common denominator: ascii codes. The ascii code for "\r" is 13, and the ascii code for "\n" is 10. Now what about the string "0d"? The ascii code for the character "0" is 48, and the ascii code for the character "d" is 100. Those strings do not have a single character in common. Even this doesn't work:

 x = '0d' + '0a'
 x.replace("\r\n", " ")
 print x


Nor will this:

x = 'd' + 'a'
x.replace("\r\n", " ")
print x


The bottom line is: converting a character to an integer then to a hex string does not end up giving you the original character--they are just different strings. So if you do this:

char = "a"
code = ord(char)
hex_str = hex(code)

print char.replace(hex_str, " ") can't expect "a" to be replaced by a space. If you examine the output here:

char = "a"
print repr(char)

code = ord(char)
print repr(code)

hex_str = hex(code)
print repr(hex_str)

print repr(
    char.replace(hex_str, " ")


You can see that 'a' is a string with one character in it, and '0x61' is a string with 4 characters in it: '0', 'x', '6', and '1', and you can never find a four character string inside a one character string.

4) Removing newlines can corrupt the data.

For some files, you do not want to replace newlines. For instance, if you were reading in a .jpg file, which is a file that contains a bunch of integers representing colors in an image, and some colors in the image happened to be represented by the number 13 followed by the number 10, your code would eliminate those colors from the output.

However, if you are writing a program to read only text files, then replacing newlines is fine. But then, different operating systems use different newlines. You are trying to replace Windows newlines(\r\n), which means your program won't work on files created by a Mac or Linux computer, which use \n for newlines. There are easy ways to solve that, but maybe you don't want to worry about that just yet.

I hope all that's not too confusing.

How to add a fragment to a programmatically generated layout?

At some point, I suppose you will add your programatically created LinearLayout to some root layout that you defined in .xml. This is just a suggestion of mine and probably one of many solutions, but it works: Simply set an ID for the programatically created layout, and add it to the root layout that you defined in .xml, and then use the set ID to add the Fragment.

It could look like this:

LinearLayout rowLayout = new LinearLayout();
// add rowLayout to the root layout somewhere here

FragmentManager fragMan = getFragmentManager();
FragmentTransaction fragTransaction = fragMan.beginTransaction();   

Fragment myFrag = new ImageFragment();
fragTransaction.add(rowLayout.getId(), myFrag , "fragment" + fragCount);

Simply choose whatever Integer value you want for the ID:


If you are using the above line of code not just once, it would probably be smart to figure out a way to create unique-IDs, in order to avoid duplicates.


Here is the full code of how it should be done: (this code is tested and works) I am adding two Fragments to a LinearLayout with horizontal orientation, resulting in the Fragments being aligned next to each other. Please also be aware, that I used a fixed height and width of 200dp, so that one Fragment does not use the full screen as it would with "match_parent".

public class MainActivity extends Activity {

    protected void onCreate(Bundle savedInstanceState) {

        LinearLayout fragContainer = (LinearLayout) findViewById(;

        LinearLayout ll = new LinearLayout(this);


        getFragmentManager().beginTransaction().add(ll.getId(), TestFragment.newInstance("I am frag 1"), "someTag1").commit();
        getFragmentManager().beginTransaction().add(ll.getId(), TestFragment.newInstance("I am frag 2"), "someTag2").commit();


public class TestFragment extends Fragment {

    public static TestFragment newInstance(String text) {

        TestFragment f = new TestFragment();

        Bundle b = new Bundle();
        b.putString("text", text);
        return f;

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View v =  inflater.inflate(R.layout.fragment, container, false);

        ((TextView) v.findViewById("text"));     
        return v;


<RelativeLayout xmlns:android=""
    tools:context=".MainActivity" >

        android:text="@string/hello_world" />

        android:orientation="vertical" >


  <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android=""
    android:layout_height="200dp" >

        android:text="" />


And this is the result of the above code: (the two Fragments are aligned next to each other) result

Is 'bool' a basic datatype in C++?

C++ does lots of automatic casting for you - that is, if you have a variable of type bool and pass it to something expecting an int, it will make it into an int for you - 0 for false and 1 for true.

I don't have my standard around to see if this is guaranteed, but every compiler I've used does this (so one can assume it will always work).

However, relying on this conversion is a bad idea. Code can stop compiling if a new method is added that overloads the int signature, etc.

Importing a Maven project into Eclipse from Git

Direct answer: Go to Files>>Import>>Git>>Project From Git (you should have GIT installed on Eclips)

calling parent class method from child class object in java

If you override a parent method in its child, child objects will always use the overridden version. But; you can use the keyword super to call the parent method, inside the body of the child method.

public class PolyTest{
    public static void main(String args[]){
        new Child().foo();

class Parent{
    public void foo(){
        System.out.println("I'm the parent.");

class Child extends Parent{
    public void foo(){
        System.out.println("I'm the child.");

This would print:

I'm the child.

Uncomment the commented line and it would print:

I'm the parent.

I'm the child.

You should look for the concept of Polymorphism.

Batch file. Delete all files and folders in a directory

del *.* instead of del *.db. That will remove everything.

sending email via php mail function goes to spam

The problem is simple that the PHP-Mail function is not using a well configured SMTP Server.

Nowadays Email-Clients and Servers perform massive checks on the emails sending server, like Reverse-DNS-Lookups, Graylisting and whatevs. All this tests will fail with the php mail() function. If you are using a dynamic ip, its even worse.

Use the PHPMailer-Class and configure it to use smtp-auth along with a well configured, dedicated SMTP Server (either a local one, or a remote one) and your problems are gone.

better way to drop nan rows in pandas

Just in case commands in previous answers doesn't work, Try this: dat.dropna(subset=['x'], inplace = True)

Can constructors be async?

if you make constructor asynchronous, after creating an object, you may fall into problems like null values instead of instance objects. For instance;

MyClass instance = new MyClass();
instance.Foo(); // null exception here

That's why they don't allow this i guess.

How do I merge my local uncommitted changes into another Git branch?

If it were about committed changes, you should have a look at git-rebase, but as pointed out in comment by VonC, as you're talking about local changes, git-stash would certainly be the good way to do this.

CORS error :Request header field Authorization is not allowed by Access-Control-Allow-Headers in preflight response

If you don't want to install the cors library and instead want to fix your original code, the other step you are missing is that Access-Control-Allow-Origin:* is wrong. When passing Authentication tokens (e.g. JWT) then you must explicitly state every url that is calling your server. You can't use "*" when doing authentication tokens.

Resource interpreted as Document but transferred with MIME type application/zip

I was experiencing the same trouble with a download manager I created. The problem I was having involved the file name being too long and the extension being clipped off.

Example: File Name : Organizational Protocols and Other Things That are Important.pd

  header("Content-Disposition: attachment; filename=$File_Name");

Solution: Increased the MySQL database field to 255 to store the file name, and performed a length check before saving the blob. If the length > 255 trim it down to 250 and add the file extension.

How to automatically indent source code?

It may be worth noting that auto-indent does not work if there are syntax errors in the document. Get rid of the red squigglies, and THEN try CTRL+K, CTRL+D, whatever...

Unfortunately MyApp has stopped. How can I solve this?

Logcat - To check the logs in the development phase of Android Studio

Initially clear the Logcat and let the app crash again so you can get only crashed log detail. You have to check the Stack trace

While, Unfortunately, MyApp has stopped. There are many reasons for it. You can check same in logs. For this, you can use the Log.e("TAG","Message");

Common error during app crash like:

  1. Coding mistake(Wrong use of keywords).
  2. Mismatch property name.
  3. Unsupported plugin(maybe).
  4. Mismatch version(maybe).
  5. Activity missing in AndroidManifest file.
  6. Permission missing in AndroidManifest file.
  7. Most common NullPointerException.
  8. Declared but not defined.

To resolve app crash error:

  • Keep in mind above points and go through it.
  • With the error, you will get the file name also in blue colour (click on them and jump to code from error is occurring).

integrating barcode scanner into php application?

I've been using something like this. Just set up a simple HTML page with an textinput. Make sure that the textinput always has focus. When you scan a barcode with your barcode scanner you will receive the code and after that a 'enter'. Realy simple then; just capture the incoming keystrokes and when the 'enter' comes in you can use AJAX to handle your code.

Color different parts of a RichTextBox string

Selecting text as said from somebody, may the selection appear momentarily. In Windows Forms applications there is no other solutions for the problem, but today I found a bad, working, way to solve: you can put a PictureBox in overlapping to the RichtextBox with the screenshot of if, during the selection and the changing color or font, making it after reappear all, when the operation is complete.

Code is here...

//The PictureBox has to be invisible before this, at creation
//tb variable is your RichTextBox
//inputPreview variable is your PictureBox
using (Graphics g = inputPreview.CreateGraphics())
    Point loc = tb.PointToScreen(new Point(0, 0));
    g.CopyFromScreen(loc, loc, tb.Size);
    Point pt = tb.GetPositionFromCharIndex(tb.TextLength);
    g.FillRectangle(new SolidBrush(Color.Red), new Rectangle(pt.X, 0, 100, tb.Height));
//Your code here (example: tb.Select(...); tb.SelectionColor = ...;)

Better is to use WPF; this solution isn't perfect, but for Winform it works.

How to get current date time in milliseconds in android

I think leverage this functionality using Java

long time= System.currentTimeMillis();

this will return current time in milliseconds mode . this will surely work

long time= System.currentTimeMillis();
android.util.Log.i("Time Class ", " Time value in millisecinds "+time);

Here is my logcat using the above function

05-13 14:38:03.149: INFO/Time Class(301): Time value in millisecinds 1368436083157

If you got any doubt with millisecond value .Check Here

EDIT : Time Zone I used to demo the code IST(+05:30) ,So if you check milliseconds that mentioned in log to match with time in log you might get a different value based your system timezone

EDIT: This is easy approach .but if you need time zone or any other details I think this won't be enough Also See this approach using android api support

Can you hide the controls of a YouTube embed without enabling autoplay?

To continue using the iframe YouTube, you should only have to change ?autoplay=1 to ?autoplay=0.

Another way to accomplish this would be by using the YouTube JavaScript Player API. (

Edit: the YouTube JavaScript Player API is no longer supported.

<div id="howToVideo"></div>

<script type="application/javascript">

    var ga = document.createElement('script');
    ga.type = 'text/javascript';
    ga.async = false;
    ga.src = '';
    var s = document.getElementsByTagName('script')[0];
    s.parentNode.insertBefore(ga, s);

    var done = false;
    var player;

    function onYouTubePlayerAPIReady() {
        player = new YT.Player('howToVideo', {
            height: '390',
            width: '640',
            videoId: 'qUJYqhKZrwA',
        playerVars: {
            controls: 0,
            disablekb: 1
          events: {
            'onReady': onPlayerReady,
            'onStateChange': onPlayerStateChange
    function onPlayerReady(evt) {
        console.log('onPlayerReady', evt);
    function onPlayerStateChange(evt) {
        console.log('onPlayerStateChange', evt);
        if ( == YT.PlayerState.PLAYING && !done) {
            setTimeout(stopVideo, 6000);
            done = true;

    function stopVideo() {


Here is a jsfiddle for the example:

Note that player controls are disabled in the "playerVars" part of the player. The one sacrifice you make is that users are still able to pause the video by clicking on it. I would suggest writing a simple javascript function that subscribes to a stop event and calls player.playVideo().

Best way to select random rows PostgreSQL

Given your specifications (plus additional info in the comments),

  • You have a numeric ID column (integer numbers) with only few (or moderately few) gaps.
  • Obviously no or few write operations.
  • Your ID column has to be indexed! A primary key serves nicely.

The query below does not need a sequential scan of the big table, only an index scan.

First, get estimates for the main query:

SELECT count(*) AS ct              -- optional
     , min(id)  AS min_id
     , max(id)  AS max_id
     , max(id) - min(id) AS id_span
FROM   big;

The only possibly expensive part is the count(*) (for huge tables). Given above specifications, you don't need it. An estimate will do just fine, available at almost no cost (detailed explanation here):

SELECT reltuples AS ct FROM pg_class WHERE oid = 'schema_name.big'::regclass;

As long as ct isn't much smaller than id_span, the query will outperform other approaches.

WITH params AS (
    SELECT 1       AS min_id           -- minimum id <= current min id
         , 5100000 AS id_span          -- rounded up. (max_id - min_id + buffer)
    SELECT p.min_id + trunc(random() * p.id_span)::integer AS id
    FROM   params p
          ,generate_series(1, 1100) g  -- 1000 + buffer
    GROUP  BY 1                        -- trim duplicates
    ) r
JOIN   big USING (id)
LIMIT  1000;                           -- trim surplus
  • Generate random numbers in the id space. You have "few gaps", so add 10 % (enough to easily cover the blanks) to the number of rows to retrieve.

  • Each id can be picked multiple times by chance (though very unlikely with a big id space), so group the generated numbers (or use DISTINCT).

  • Join the ids to the big table. This should be very fast with the index in place.

  • Finally trim surplus ids that have not been eaten by dupes and gaps. Every row has a completely equal chance to be picked.

Short version

You can simplify this query. The CTE in the query above is just for educational purposes:

    SELECT DISTINCT 1 + trunc(random() * 5100000)::integer AS id
    FROM   generate_series(1, 1100) g
    ) r
JOIN   big USING (id)
LIMIT  1000;

Refine with rCTE

Especially if you are not so sure about gaps and estimates.

WITH RECURSIVE random_pick AS (
   FROM  (
      SELECT 1 + trunc(random() * 5100000)::int AS id
      FROM   generate_series(1, 1030)  -- 1000 + few percent - adapt to your needs
      LIMIT  1030                      -- hint for query planner
      ) r
   JOIN   big b USING (id)             -- eliminate miss

   UNION                               -- eliminate dupe
   SELECT b.*
   FROM  (
      SELECT 1 + trunc(random() * 5100000)::int AS id
      FROM   random_pick r             -- plus 3 percent - adapt to your needs
      LIMIT  999                       -- less than 1000, hint for query planner
      ) r
   JOIN   big b USING (id)             -- eliminate miss
FROM   random_pick
LIMIT  1000;  -- actual limit

We can work with a smaller surplus in the base query. If there are too many gaps so we don't find enough rows in the first iteration, the rCTE continues to iterate with the recursive term. We still need relatively few gaps in the ID space or the recursion may run dry before the limit is reached - or we have to start with a large enough buffer which defies the purpose of optimizing performance.

Duplicates are eliminated by the UNION in the rCTE.

The outer LIMIT makes the CTE stop as soon as we have enough rows.

This query is carefully drafted to use the available index, generate actually random rows and not stop until we fulfill the limit (unless the recursion runs dry). There are a number of pitfalls here if you are going to rewrite it.

Wrap into function

For repeated use with varying parameters:

CREATE OR REPLACE FUNCTION f_random_sample(_limit int = 1000, _gaps real = 1.03)
   _surplus  int := _limit * _gaps;
   _estimate int := (           -- get current estimate from system
      SELECT c.reltuples * _gaps
      FROM   pg_class c
      WHERE  c.oid = 'big'::regclass);

   WITH RECURSIVE random_pick AS (
      SELECT *
      FROM  (
         SELECT 1 + trunc(random() * _estimate)::int
         FROM   generate_series(1, _surplus) g
         LIMIT  _surplus           -- hint for query planner
         ) r (id)
      JOIN   big USING (id)        -- eliminate misses

      UNION                        -- eliminate dupes
      SELECT *
      FROM  (
         SELECT 1 + trunc(random() * _estimate)::int
         FROM   random_pick        -- just to make it recursive
         LIMIT  _limit             -- hint for query planner
         ) r (id)
      JOIN   big USING (id)        -- eliminate misses
   FROM   random_pick
   LIMIT  _limit;
$func$  LANGUAGE plpgsql VOLATILE ROWS 1000;


SELECT * FROM f_random_sample();
SELECT * FROM f_random_sample(500, 1.05);

You could even make this generic to work for any table: Take the name of the PK column and the table as polymorphic type and use EXECUTE ... But that's beyond the scope of this question. See:

Possible alternative

IF your requirements allow identical sets for repeated calls (and we are talking about repeated calls) I would consider a materialized view. Execute above query once and write the result to a table. Users get a quasi random selection at lightening speed. Refresh your random pick at intervals or events of your choosing.

Postgres 9.5 introduces TABLESAMPLE SYSTEM (n)

Where n is a percentage. The manual:

The BERNOULLI and SYSTEM sampling methods each accept a single argument which is the fraction of the table to sample, expressed as a percentage between 0 and 100. This argument can be any real-valued expression.

Bold emphasis mine. It's very fast, but the result is not exactly random. The manual again:

The SYSTEM method is significantly faster than the BERNOULLI method when small sampling percentages are specified, but it may return a less-random sample of the table as a result of clustering effects.

The number of rows returned can vary wildly. For our example, to get roughly 1000 rows:

SELECT * FROM big TABLESAMPLE SYSTEM ((1000 * 100) / 5100000.0);


Or install the additional module tsm_system_rows to get the number of requested rows exactly (if there are enough) and allow for the more convenient syntax:


See Evan's answer for details.

But that's still not exactly random.

Do HTTP POST methods send data as a QueryString?

The best way to visualize this is to use a packet analyzer like Wireshark and follow the TCP stream. HTTP simply uses TCP to send a stream of data starting with a few lines of HTTP headers. Often this data is easy to read because it consists of HTML, CSS, or XML, but it can be any type of data that gets transfered over the internet (Executables, Images, Video, etc).

For a GET request, your computer requests a specific URL and the web server usually responds with a 200 status code and the the content of the webpage is sent directly after the HTTP response headers. This content is the same content you would see if you viewed the source of the webpage in your browser. The query string you mentioned is just part of the URL and gets included in the HTTP GET request header that your computer sends to the web server. Below is an example of an HTTP GET request to, followed by a 302 redirect response from the server. Some of the HTTP Headers are wrapped due to the size of the viewing window (these really only take one line each), and the 302 redirect includes a simple HTML webpage with a link to the redirected webpage (Most browsers will automatically redirect any 302 response to the URL listed in the Location header instead of displaying the HTML response):

HTTP GET with 302 redirect

For a POST request, you may still have a query string, but this is uncommon and does not have anything to do with the data that you are POSTing. Instead, the data is included directly after the HTTP headers that your browser sends to the server, similar to the 200 response that the web server uses to respond to a GET request. In the case of POSTing a simple web form this data is encoded using the same URL encoding that a query string uses, but if you are using a SOAP web service it could also be encoded using a multi-part MIME format and XML data.

For example here is what an HTTP POST to an XML based SOAP web service located at looks like in Wireshark Follow TCP Stream:


Dark theme in Netbeans 7 or 8

u can use Dark theme Plugin

Tools > Plugin > Dark theme and Feel

and it is work :)

Case insensitive string compare in LINQ-to-SQL

To perform case sensitive Linq to Sql queries declare ‘string’ fields to be case sensitive by specifying the server data type by using one of the following;

varchar(4000) COLLATE SQL_Latin1_General_CP1_CS_AS 


nvarchar(Max) COLLATE SQL_Latin1_General_CP1_CS_AS

Note: The ‘CS’ in the above collation types means ‘Case Sensitive’.

This can be entered in the “Server Data Type” field when viewing a property using Visual Studio DBML Designer.

For more details see

What is the best way to compare floats for almost-equality in Python?

Useful for the case where you want to make sure 2 numbers are the same 'up to precision', no need to specify the tolerance:

  • Find minimum precision of the 2 numbers

  • Round both of them to minimum precision and compare

def isclose(a,b):                                       
    aprec=len(astr.split('.')[1]) if '.' in astr else 0 
    bprec=len(bstr.split('.')[1]) if '.' in bstr else 0 
    return round(a,prec)==round(b,prec)                               

As written, only works for numbers without the 'e' in their string representation ( meaning 0.9999999999995e-4 < number <= 0.9999999999995e11 )


>>> isclose(10.0,10.049)
>>> isclose(10.0,10.05)

How do I correctly setup and teardown for my pytest class with tests?

According to Fixture finalization / executing teardown code, the current best practice for setup and teardown is to use yield instead of return:

import pytest

def resource():
    yield "resource"

class TestResource:
    def test_that_depends_on_resource(self, resource):
        print("testing {}".format(resource))

Running it results in

$ py.test --capture=no
=== test session starts ===
platform darwin -- Python 2.7.10, pytest-3.0.2, py-1.4.31, pluggy-0.3.1
collected 1 items setup
testing resource

=== 1 passed in 0.01 seconds ===

Another way to write teardown code is by accepting a request-context object into your fixture function and calling its request.addfinalizer method with a function that performs the teardown one or multiple times:

import pytest

def resource(request):

    def teardown():
    return "resource"

class TestResource:
    def test_that_depends_on_resource(self, resource):
        print("testing {}".format(resource))

Deck of cards JAVA

There is a lot of error in your program.

  1. Calculation of index. I think it should be Math.random()%deck.length

  2. In the display of card. According to me, you should make a class of card which has rank suit and make the array of that class type

If you want I can give you the Complete structure of that but it is better if u make it by yourself

Why can I ping a server but not connect via SSH?

ping (ICMP protocol) and ssh are two different protocols.

  1. It could be that ssh service is not running or not installed

  2. firewall restriction (local to server like iptables or even sshd config lock down ) or (external firewall that protects incomming traffic to network hosting

First check is to see if ssh port is up

nc -v -w 1 -z 22

if it succeeds then ssh should communicate if not then it will never work until restriction is lifted or ssh is started

How do I link a JavaScript file to a HTML file?

this is demo code but it will help 

<!DOCTYPE html>
<title>APITABLE 3</title>
<script src=""></script>


    type: "GET",
    url: "",

    data: '$format=json',

    dataType: 'json',
    success: function (data) {

                        +"</tr>" )




    <table id="apiTable">

        <tbody id="apiData"></tbody>    


TypeScript: casting HTMLElement

To end up with:

  • an actual Array object (not a NodeList dressed up as an Array)
  • a list that is guaranteed to only include HTMLElements, not Nodes force-casted to HTMLElements
  • a warm fuzzy feeling to do The Right Thing

Try this:

let nodeList : NodeList = document.getElementsByTagName('script');
let elementList : Array<HTMLElement> = [];

if (nodeList) {
    for (let i = 0; i < nodeList.length; i++) {
        let node : Node = nodeList[i];

        // Make sure it's really an Element
        if (node.nodeType == Node.ELEMENT_NODE) {
            elementList.push(node as HTMLElement);


Possible reason for NGINX 499 error codes

Once I got 499 "Request has been forbidden by antivirus" as an AJAX http response (false positive by Kaspersky Internet Security with light heuristic analysis, deep heuristic analysis knew correctly there was nothing wrong).

How can I display just a portion of an image in HTML/CSS?

One way to do it is to set the image you want to display as a background in a container (td, div, span etc) and then adjust background-position to get the sprite you want.

How to get query string parameter from MVC Razor markup?

For Core 2


What does SQL clause "GROUP BY 1" mean?

It means to group by the first column regardless of what it's called. You can do the same with ORDER BY.

Hive: Filtering Data between Specified Dates when Date is a String

Try this:

select * from your_table
where date >= '2020-10-01'  

Spring MVC: How to return image in @ResponseBody?

 @RequestMapping(value = "/get-image",method = RequestMethod.GET)
public ResponseEntity<byte[]> getImage() throws IOException {
    RandomAccessFile f = new RandomAccessFile("/home/vivex/apache-tomcat-7.0.59/tmpFiles/1.jpg", "r");
    byte[] b = new byte[(int)f.length()];
    final HttpHeaders headers = new HttpHeaders();

    return new ResponseEntity<byte[]>(b, headers, HttpStatus.CREATED);


Worked For Me.

Setting up a JavaScript variable from Spring model by using Thymeleaf

According to the official documentation:

<script th:inline="javascript">

    var message = /*[[${message}]]*/ 'default';


What causes this error? "Runtime error 380: Invalid property value"

Old thread, but here is an answer.

Problematic fonts with voyager

ie. if you install some corel suite, drop some language options away. We dig through this with process monitor and found the reason, with us it was these two font files.

DFKai71.ttf dfmw5.ttf

We had same problem and it was fixed by removing these two font files from windows\fonts folder.

IN vs OR in the SQL WHERE Clause

The best way to find out is looking at the Execution Plan.

I tried it with Oracle, and it was exactly the same.

CREATE TABLE performance_test AS ( SELECT * FROM dba_objects );

SELECT * FROM performance_test

Even though the query uses IN, the Execution Plan says that it uses OR:

| Id  | Operation         | Name             | Rows  | Bytes | Cost (%CPU)| Time     |    
|   0 | SELECT STATEMENT  |                  |     8 |  1416 |   163   (2)| 00:00:02 |    
|*  1 |  TABLE ACCESS FULL| PERFORMANCE_TEST |     8 |  1416 |   163   (2)| 00:00:02 |    

Predicate Information (identified by operation id):                                       

   1 - filter("OBJECT_NAME"='DBMS_LOB' OR "OBJECT_NAME"='DBMS_REGISTRY' OR                

What does 'foo' really mean?

foo = File or Object. It is used in place of an object variable or file name.

Converting from Integer, to BigInteger

The method you want is BigInteger#valueOf(long val).


BigInteger bi = BigInteger.valueOf(myInteger.intValue());

Making a String first is unnecessary and undesired.

Can you remove elements from a std::list while iterating through it?

I think you have a bug there, I code this way:

for (std::list<CAudioChannel *>::iterator itAudioChannel = audioChannels.begin();
             itAudioChannel != audioChannels.end(); )
    CAudioChannel *audioChannel = *itAudioChannel;
    std::list<CAudioChannel *>::iterator itCurrentAudioChannel = itAudioChannel;

    if (audioChannel->destroyMe)
        delete audioChannel;
    audioChannel->Mix(outBuffer, numSamples);

Replacing Pandas or Numpy Nan with a None to use with MysqlDB

After stumbling around, this worked for me:

df = df.astype(object).where(pd.notnull(df),None)

First letter capitalization for EditText

testEditText.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_FLAG_CAP_WORDS);   

or android:inputType="textCapSentences" will only work If your device keyboard Auto Capitalize Setting enabled.

Match all elements having class name starting with a specific string

The following should do the trick:

div[class^='myclass'], div[class*=' myclass']{
    color: #F00;

Edit: Added wildcard (*) as suggested by David

Export and Import all MySQL databases at one time

Export all databases in Ubuntu

1 - mysqldump -u root -p --databases database1 database2 > ~/Desktop/databases_1_2.sql


2 - mysqldump -u root -p --all_databases > ~/Desktop/all_databases.sql

enter image description here

JavaScript open in a new window, not tab

OK, after making a lot of test, here my concluson:

When you perform:'www.yourdomain.tld','_blank');'www.yourdomain.tld','myWindow');

or whatever you put in the destination field, this will change nothing: the new page will be opened in a new tab (so depend on user preference)

If you want the page to be opened in a new "real" window, you must put extra parameter. Like:'www.yourdomain.tld', 'mywindow','location=1,status=1,scrollbars=1, resizable=1, directories=1, toolbar=1, titlebar=1');

After testing, it seems the extra parameter you use, dont' really matter: this is not the fact you put "this parameter" or "this other one" which create the new "real window" but the fact there is new parameter(s).

But something is confused and may explain a lot of wrong answers:


 win1 ='myurl1', 'ID_WIN');
 win2 ='myurl2', 'ID_WIN', 'location=1,status=1,scrollbars=1');

And this:

 win2 ='myurl2', 'ID_WIN', 'location=1,status=1,scrollbars=1');
 win1 ='myurl1', 'ID_WIN');

will NOT give the same result.

In the first case, as you first open a page without extra parameter, it will open in a new tab. And in this case, the second call will be also opened in this tab because of the name you give.

In second case, as your first call is made with extra parameter, the page will be opened in a new "real window". And in that case, even if the second call is made without the extra parameter, it will also be opened in this new "real window"... but same tab!

This mean the first call is important as it decided where to put the page.

Python: How to get stdout after running os.system?

These answers didn't work for me. I had to use the following:

import subprocess
p = subprocess.Popen(["pwd"], stdout=subprocess.PIPE)
out =
print out

Or as a function (using shell=True was required for me on Python 2.6.7 and check_output was not added until 2.7, making it unusable here):

def system_call(command):
    p = subprocess.Popen([command], stdout=subprocess.PIPE, shell=True)

How do I to insert data into an SQL table using C# as well as implement an upload function?

You should use parameters in your query to prevent attacks, like if someone entered '); drop table ArticlesTBL;--' as one of the values.

string query = "INSERT INTO ArticlesTBL (ArticleTitle, ArticleContent, ArticleType, ArticleImg, ArticleBrief,  ArticleDateTime, ArticleAuthor, ArticlePublished, ArticleHomeDisplay, ArticleViews)";
query += " VALUES (@ArticleTitle, @ArticleContent, @ArticleType, @ArticleImg, @ArticleBrief, @ArticleDateTime, @ArticleAuthor, @ArticlePublished, @ArticleHomeDisplay, @ArticleViews)";

SqlCommand myCommand = new SqlCommand(query, myConnection);
myCommand.Parameters.AddWithValue("@ArticleTitle", ArticleTitleTextBox.Text);
myCommand.Parameters.AddWithValue("@ArticleContent", ArticleContentTextBox.Text);
// ... other parameters

Exploits of a Mom


What's the fastest way to convert String to Number in JavaScript?

There are 4 ways to do it as far as I know.

parseInt(x, 10);

By this quick test I made, it actually depends on browsers.

Implicit marked the fastest on 3 browsers, but it makes the code hard to read… So choose whatever you feel like it!

editing PATH variable on mac

environment.plst file loads first on MAC so put the path on it.

For 1st time use, use the following command

export PATH=$PATH: /path/to/set

How to call a REST web service API from JavaScript?

           "key":"your key",
     "Accept":"application/json",//depends on your api
      "Content-type":"application/x-www-form-urlencoded"//depends on your api
        },   url:"url you need",
          var r=JSON.parse(response);

Generate a Hash from string in Javascript

Based on accepted answer in ES6. Smaller, maintainable and works in modern browsers.

function hashCode(str) {_x000D_
  return str.split('').reduce((prevHash, currVal) =>_x000D_
    (((prevHash << 5) - prevHash) + currVal.charCodeAt(0))|0, 0);_x000D_
// Test_x000D_
console.log("hashCode(\"Hello!\"): ", hashCode('Hello!'));

EDIT (2019-11-04):

one-liner arrow function version :

const hashCode = s => s.split('').reduce((a,b) => (((a << 5) - a) + b.charCodeAt(0))|0, 0)_x000D_
// test_x000D_

A field initializer cannot reference the nonstatic field, method, or property

You need to put that code into the constructor of your class:

private Reminders reminder = new Reminders();
private dynamic defaultReminder;

public YourClass()
    defaultReminder = reminder.TimeSpanText[TimeSpan.FromMinutes(15)];

The reason is that you can't use one instance variable to initialize another one using a field initializer.

What is a handle in C++?

HANDLE hnd; is the same as void * ptr;

HANDLE is a typedef defined in the winnt.h file in Visual Studio (Windows):

typedef void *HANDLE;

Read more about HANDLE

Reading a json file in Android

Put that file in assets.

For project created in Android Studio project you need to create assets folder under the main folder.

Read that file as:

public String loadJSONFromAsset(Context context) {
        String json = null;
        try {
            InputStream is = context.getAssets().open("file_name.json");

            int size = is.available();

            byte[] buffer = new byte[size];



            json = new String(buffer, "UTF-8");

        } catch (IOException ex) {
            return null;
        return json;


and then you can simply read this string return by this function as

JSONObject obj = new JSONObject(json_return_by_the_function);

For further details regarding JSON see

Hope you will get what you want.

What does void* mean and how to use it?

C11 standard (n1570) § al1 p55 says :

A pointer to void may be converted to or from a pointer to any object type. A pointer to any object type may be converted to a pointer to void and back again; the result shall compare equal to the original pointer.

You can use this generic pointer to store a pointer to any object type, but you can't use usual arithmetic operations with it and you can't deference it.

Jquery Setting Value of Input Field

use this code for set value in input tag by another id.


or use this code for set value in input tag using classname="formdata"


How to add a browser tab icon (favicon) for a website?

There are a number of different icons and even splash screens that you can set for various devices. This answer goes through how to support them all.

Here are some snippets I have used with relevant links to where I gathered the information. See my blog for more information and more information about the ASP.NET MVC Boilerplate project template with all this built in right out of the box (Including sample image files).

Add the following mark-up to your html head. The commented out sections are entirely optional. While the uncommented sections are recommended to cover all icon usages. Don't be scared, most if it is comments to help you.

<!-- Icons & Platform Specific Settings - Favicon generator used to generate the icons below -->
<!-- shortcut icon - It is best to add this icon to the root of your site and only use this link element if you move it somewhere else. This file contains the following sizes 16x16, 32x32 and 48x48. -->
<!--<link rel="shortcut icon" href="favicon.ico">-->
<!-- favicon-96x96.png - For Google TV. -->
<link rel="icon" type="image/png" href="/content/images/favicon-96x96.png" sizes="96x96">
<!-- favicon-16x16.png - The classic favicon, displayed in the tabs. -->
<link rel="icon" type="image/png" href="/content/images/favicon-16x16.png" sizes="16x16">
<!-- favicon-32x32.png - For Safari on Mac OS. -->
<link rel="icon" type="image/png" href="/content/images/favicon-32x32.png" sizes="32x32">

<!-- Android/Chrome -->
<!-- manifest-json - The location of the browser configuration file. It contains locations of icon files, name of the application and default device screen orientation. Note that the name field is mandatory. -->
<link rel="manifest" href="/content/icons/manifest.json">
<!-- theme-color - The colour of the toolbar in Chrome M39+ -->
<meta name="theme-color" content="#1E1E1E">
<!-- favicon-192x192.png - For Android Chrome M36 to M38 this HTML is used. M39+ uses the manifest.json file. -->
<link rel="icon" type="image/png" href="/content/icons/favicon-192x192.png" sizes="192x192">
<!-- mobile-web-app-capable - Run Android/Chrome version M31 to M38 in standalone mode, hiding the browser chrome. -->
<!-- <meta name="mobile-web-app-capable" content="yes"> -->

<!-- Apple Icons - You can move all these icons to the root of the site and remove these link elements, if you don't mind the clutter. -->
<!-- apple-mobile-web-app-title - The name of the application if pinned to the IOS start screen. -->
<!--<meta name="apple-mobile-web-app-title" content="">-->
<!-- apple-mobile-web-app-capable - Hide the browsers user interface on IOS, when the app is run in 'standalone' mode. Any links to other pages that are clicked whilst your app is in standalone mode will launch the full Safari browser. -->
<!--<meta name="apple-mobile-web-app-capable" content="yes">-->
<!-- apple-mobile-web-app-status-bar-style - default/black/black-translucent Styles the IOS status bar. Using black-translucent makes it transparent and overlays it on top of your site, so make sure you have enough margin. -->
<!--<meta name="apple-mobile-web-app-status-bar-style" content="black">-->
<!-- apple-touch-icon-57x57.png - Android Stock Browser and non-Retina iPhone and iPod Touch -->
<link rel="apple-touch-icon" sizes="57x57" href="/content/images/apple-touch-icon-57x57.png">
<!-- apple-touch-icon-114x114.png - iPhone (with 2× display) iOS = 6 -->
<link rel="apple-touch-icon" sizes="114x114" href="/content/images/apple-touch-icon-114x114.png">
<!-- apple-touch-icon-72x72.png - iPad mini and the first- and second-generation iPad (1× display) on iOS = 6 -->
<link rel="apple-touch-icon" sizes="72x72" href="/content/images/apple-touch-icon-72x72.png">
<!-- apple-touch-icon-144x144.png - iPad (with 2× display) iOS = 6 -->
<link rel="apple-touch-icon" sizes="144x144" href="/content/images/apple-touch-icon-144x144.png">
<!-- apple-touch-icon-60x60.png - Same as apple-touch-icon-57x57.png, for non-retina iPhone with iOS7. -->
<link rel="apple-touch-icon" sizes="60x60" href="/content/images/apple-touch-icon-60x60.png">
<!-- apple-touch-icon-120x120.png - iPhone (with 2× and 3 display) iOS = 7 -->
<link rel="apple-touch-icon" sizes="120x120" href="/content/images/apple-touch-icon-120x120.png">
<!-- apple-touch-icon-76x76.png - iPad mini and the first- and second-generation iPad (1× display) on iOS = 7 -->
<link rel="apple-touch-icon" sizes="76x76" href="/content/images/apple-touch-icon-76x76.png">
<!-- apple-touch-icon-152x152.png - iPad 3+ (with 2× display) iOS = 7 -->
<link rel="apple-touch-icon" sizes="152x152" href="/content/images/apple-touch-icon-152x152.png">
<!-- apple-touch-icon-180x180.png - iPad and iPad mini (with 2× display) iOS = 8 -->
<link rel="apple-touch-icon" sizes="180x180" href="/content/images/apple-touch-icon-180x180.png">

<!-- Apple Startup Images - These are shown when the page is loading if the site is pinned -->
<!-- apple-touch-startup-image-1536x2008.png - iOS 6 & 7 iPad (retina, portrait) -->
<link rel="apple-touch-startup-image"
      media="(device-width: 768px) and (device-height: 1024px) and (orientation: portrait) and (-webkit-device-pixel-ratio: 2)">
<!-- apple-touch-startup-image-1496x2048.png - iOS 6 & 7 iPad (retina, landscape) -->
<link rel="apple-touch-startup-image"
      media="(device-width: 768px) and (device-height: 1024px) and (orientation: landscape) and (-webkit-device-pixel-ratio: 2)">
<!-- apple-touch-startup-image-768x1004.png - iOS 6 iPad (portrait) -->
<link rel="apple-touch-startup-image"
      media="(device-width: 768px) and (device-height: 1024px) and (orientation: portrait) and (-webkit-device-pixel-ratio: 1)">
<!-- apple-touch-startup-image-748x1024.png - iOS 6 iPad (landscape) -->
<link rel="apple-touch-startup-image"
      media="(device-width: 768px) and (device-height: 1024px) and (orientation: landscape) and (-webkit-device-pixel-ratio: 1)">
<!-- apple-touch-startup-image-640x1096.png - iOS 6 & 7 iPhone 5 -->
<link rel="apple-touch-startup-image"
      media="(device-width: 320px) and (device-height: 568px) and (-webkit-device-pixel-ratio: 2)">
<!-- apple-touch-startup-image-640x920.png - iOS 6 & 7 iPhone (retina) -->
<link rel="apple-touch-startup-image"
      media="(device-width: 320px) and (device-height: 480px) and (-webkit-device-pixel-ratio: 2)">
<!-- apple-touch-startup-image-320x460.png - iOS 6 iPhone -->
<link rel="apple-touch-startup-image"
      media="(device-width: 320px) and (device-height: 480px) and (-webkit-device-pixel-ratio: 1)">

<!-- Windows 8 Icons - If you add an RSS feed, revisit this page and regenerate the browserconfig.xml file. You will then have a cool live tile!
     browserconfig.xml - Windows 8.1 - Has been added to the root of the site. This points to the tile images and tile background colour. It contains the following images:
     mstile-70x70.png - For Windows 8.1 / IE11.
     mstile-144x144.png - For Windows 8 / IE10.
     mstile-150x150.png - For Windows 8.1 / IE11.
     mstile-310x310.png - For Windows 8.1 / IE11.
     mstile-310x150.png - For Windows 8.1 / IE11.
     See and -->
<!-- application-name - Windows 8+ - The name of the application if pinned to the start screen. -->
<!--<meta name="application-name" content="">-->
<!-- msapplication-TileColor - Windows 8 - The tile colour which shows around your tile image (msapplication-TileImage). -->
<meta name="msapplication-TileColor" content="#5cb95c">
<!-- msapplication-TileImage - Windows 8 - The tile image. -->
<meta name="msapplication-TileImage" content="/content/images/mstile-144x144.png">

My browserconfig.xml file. Full explanation above.

<?xml version="1.0" encoding="utf-8"?>
      <square70x70logo src="/Content/Images/mstile-70x70.png"/>
      <square150x150logo src="/Content/Images/mstile-150x150.png"/>
      <square310x310logo src="/Content/Images/mstile-310x310.png"/>
      <wide310x150logo src="/Content/Images/mstile-310x150.png"/>

My manifest.json file. Full explanation above.

    "name": "ASP.NET MVC Boilerplate (Required! Update This)",
    "icons": [
            "src": "\/Content\/icons\/android-chrome-36x36.png",
            "sizes": "36x36",
            "type": "image\/png",
            "density": "0.75"
            "src": "\/Content\/icons\/android-chrome-48x48.png",
            "sizes": "48x48",
            "type": "image\/png",
            "density": "1.0"
            "src": "\/Content\/icons\/android-chrome-72x72.png",
            "sizes": "72x72",
            "type": "image\/png",
            "density": "1.5"
            "src": "\/Content\/icons\/android-chrome-96x96.png",
            "sizes": "96x96",
            "type": "image\/png",
            "density": "2.0"
            "src": "\/Content\/icons\/android-chrome-144x144.png",
            "sizes": "144x144",
            "type": "image\/png",
            "density": "3.0"
            "src": "\/Content\/icons\/android-chrome-192x192.png",
            "sizes": "192x192",
            "type": "image\/png",
            "density": "4.0"

A list of the files in the project (Note that the names of these files are important if you decide to put some of them at the root of your project to avoid using the above meta tags):

    apple-touch-icon-precomposed.png (180x180)

Total Overhead

If you take out the comments that's 3KB of extra HTML, if you don't support splash screens that's 1.5KB. If you are using GZIP compression on your HTML content, which everyone should be doing these days, that leaves you with about 634 Bytes of overhead per request to support all platforms or 446 Bytes without splash screens. I personally think its worth it to support IOS, Android and Windows devices but its your choice, I'm just giving the options!

Side Note About The Current Web Icon/Splash Screen/Settings Situation

This situation with vendor specific icons, splash screens and special tags to control the web browser or pinned icons is ridiculous. In a perfect world we would all use a favicon.svg file which could look good at any size and could be placed at the root of the page. Only FireFox supports this at the time of writing (See

However, icons are not the only setting these days, there are several other vendor specific settings (shown above) but a favicon.svg file would cover most use cases.


Updated to include the new Android/Chrome version M39+ favicon/theming options. Interestingly, they have gone with a similar approach to Microsoft but are using a JSON file instead of XML.

How to JUnit test that two List<E> contain the same elements in the same order?

assertTrue()/assertFalse() : to use only to assert boolean result returned

assertTrue(Iterables.elementsEqual(argumentComponents, returnedComponents));

You want to use Assert.assertTrue() or Assert.assertFalse() as the method under test returns a boolean value.
As the method returns a specific thing such as a List that should contain some expected elements, asserting with assertTrue() in this way : Assert.assertTrue(myActualList.containsAll(myExpectedList) is an anti pattern.
It makes the assertion easy to write but as the test fails, it also makes it hard to debug because the test runner will only say to you something like :

expected true but actual is false

Assert.assertEquals(Object, Object) in JUnit4 or Assertions.assertIterableEquals(Iterable, Iterable) in JUnit 5 : to use only as both equals() and toString() are overrided for the classes (and deeply) of the compared objects

It matters because the equality test in the assertion relies on equals() and the test failure message relies on toString() of the compared objects.
As String overrides both equals() and toString(), it is perfectly valid to assert the List<String> with assertEquals(Object,Object). And about this matter : you have to override equals() in a class because it makes sense in terms of object equality, not only to make assertions easier in a test with JUnit.
To make assertions easier you have other ways (that you can see in the next points of the answer).

Is Guava a way to perform/build unit test assertions ?

Is Google Guava Iterables.elementsEqual() the best way, provided I have the library in my build path, to compare those two lists?

No it is not. Guava is not an library to write unit test assertions.
You don't need it to write most (all I think) of unit tests.

What's the canonical way to compare lists for unit tests?

As a good practice I favor assertion/matcher libraries.

I cannot encourage JUnit to perform specific assertions because this provides really too few and limited features : it performs only an assertion with a deep equals.
Sometimes you want to allow any order in the elements, sometimes you want to allow that any elements of the expected match with the actual, and so for...

So using a unit test assertion/matcher library such as Hamcrest or AssertJ is the correct way.
The actual answer provides a Hamcrest solution. Here is a AssertJ solution.

org.assertj.core.api.ListAssert.containsExactly() is what you need : it verifies that the actual group contains exactly the given values and nothing else, in order as stated :

Verifies that the actual group contains exactly the given values and nothing else, in order.

Your test could look like :

import org.assertj.core.api.Assertions;
import org.junit.jupiter.api.Test;

void ofComponent_AssertJ() throws Exception {
   MyObject myObject = MyObject.ofComponents("One", "Two", "Three");
             .containsExactly("One", "Two", "Three");

A AssertJ good point is that declaring a List as expected is needless : it makes the assertion straighter and the code more readable :

         .containsExactly("One", "Two", "Three");

And if the test fails :

// Fail : Three was not expected 
          .containsExactly("One", "Two");

you get a very clear message such as :



<["One", "Two", "Three"]>

to contain exactly (and in same order):

<["One", "Two"]>

but some elements were not expected:


Assertion/matcher libraries are a must because these will really further

Suppose that MyObject doesn't store Strings but Foos instances such as :

public class MyFooObject {

    private List<Foo> values;
    public static MyFooObject ofComponents(Foo... values) {
        // ...

    public List<Foo> getComponents(){
        return new ArrayList<>(values);

That is a very common need. With AssertJ the assertion is still simple to write. Better you can assert that the list content are equal even if the class of the elements doesn't override equals()/hashCode() while JUnit ways require that :

import org.assertj.core.api.Assertions;
import static org.assertj.core.groups.Tuple.tuple;
import org.junit.jupiter.api.Test;

void ofComponent() throws Exception {
    MyFooObject myObject = MyFooObject.ofComponents(new Foo(1, "One"), new Foo(2, "Two"), new Foo(3, "Three"));

              .extracting(Foo::getId, Foo::getName)
              .containsExactly(tuple(1, "One"),
                               tuple(2, "Two"),
                               tuple(3, "Three"));

Eclipse error: "Editor does not contain a main type"

Try closing and reopening the file, then press Ctrl+F11.

Verify that the name of the file you are running is the same as the name of the project you are working in, and that the name of the public class in that file is the same as the name of the project you are working in as well.

Otherwise, restart Eclipse. Let me know if this solves the problem! Otherwise, comment, and I'll try and help.

Opening Android Settings programmatically

Use this intent to open security and location screen in settings app of android device

    startActivity(new Intent(Settings.ACTION_SECURITY_SETTINGS));

How to Set Active Tab in jQuery Ui

You can use this:

$(document).ready(function() {
    $('#action').click(function() {
        var selected = $("#tabs").tabs("option", "selected");
        $("#tabs").tabs("option", "selected", selected + 1);

Also consider changing the input type as button instead of submit unless you want to submit the page.

How to update/modify an XML file in python?

Useful Python XML parsers:

  1. Minidom - functional but limited
  2. ElementTree - decent performance, more functionality
  3. lxml - high-performance in most cases, high functionality including real xpath support

Any of those is better than trying to update the XML file as strings of text.

What that means to you:

Open your file with an XML parser of your choice, find the node you're interested in, replace the value, serialize the file back out.

How to avoid using Select in Excel VBA

Please note that in the following I'm comparing the Select approach (the one that the OP wants to avoid), with the Range approach (and this is the answer to the question). So don't stop reading when you see the first Select.

It really depends on what you are trying to do. Anyway, a simple example could be useful. Let's suppose that you want to set the value of the active cell to "foo". Using ActiveCell you would write something like this:

Sub Macro1()
    ActiveCell.Value = "foo"
End Sub

If you want to use it for a cell that is not the active one, for instance for "B2", you should select it first, like this:

Sub Macro2()
End Sub

Using Ranges you can write a more generic macro that can be used to set the value of any cell you want to whatever you want:

Sub SetValue(cellAddress As String, aVal As Variant)
    Range(cellAddress).Value = aVal
End Sub

Then you can rewrite Macro2 as:

Sub Macro2()
    SetCellValue "B2", "foo"
End Sub

And Macro1 as:

Sub Macro1()
    SetValue ActiveCell.Address, "foo"
End Sub

Sending email with attachments from C#, attachments arrive as Part 1.2 in Thunderbird

I've made a short code to do that and I want to share it with you.

Here the main code:

public void Send(string from, string password, string to, string Message, string subject, string host, int port, string file)

  MailMessage email = new MailMessage();
  email.From = new MailAddress(from);
  email.Subject = subject;
  email.Body = Message;
  SmtpClient smtp = new SmtpClient(host, port);
  smtp.UseDefaultCredentials = false;
  NetworkCredential nc = new NetworkCredential(from, password);
  smtp.Credentials = nc;
  smtp.EnableSsl = true;
  email.IsBodyHtml = true;
  email.Priority = MailPriority.Normal;
  email.BodyEncoding = Encoding.UTF8;

  if (file.Length > 0)
    Attachment attachment;
    attachment = new Attachment(file);

  // smtp.Send(email);
  smtp.SendCompleted += new SendCompletedEventHandler(SendCompletedCallBack);
  string userstate = "sending ...";
  smtp.SendAsync(email, userstate);

private static void SendCompletedCallBack(object sender,AsyncCompletedEventArgs e) {
  string result = "";
  if (e.Cancelled)
    MessageBox.Show(string.Format("{0} send canceled.", e.UserState),"Message",MessageBoxButtons.OK,MessageBoxIcon.Information);
  else if (e.Error != null)
    MessageBox.Show(string.Format("{0} {1}", e.UserState, e.Error), "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
  else {
    MessageBox.Show("your message is sended", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);


In your button do stuff like this
you can add your jpg or pdf files and more .. this is just an example

using (OpenFileDialog attachement = new OpenFileDialog()
  Filter = "Exel Client|*.png",
  ValidateNames = true
if (attachement.ShowDialog() == DialogResult.OK)
  Send("[email protected]", "gmail_password", 
       "[email protected]", "just smile ", "mail with attachement",
       "", 587, attachement.FileName);


3-dimensional array in numpy

You are right, you are creating a matrix with 2 rows, 3 columns and 4 depth. Numpy prints matrixes different to Matlab:


>>> import numpy as np
>>> np.zeros((2,3,2))
 array([[[ 0.,  0.],
    [ 0.,  0.],
    [ 0.,  0.]],

   [[ 0.,  0.],
    [ 0.,  0.],
    [ 0.,  0.]]])


>> zeros(2, 3, 2)
 ans(:,:,1) =
     0     0     0
     0     0     0
 ans(:,:,2) =
     0     0     0
     0     0     0

However you are calculating the same matrix. Take a look to Numpy for Matlab users, it will guide you converting Matlab code to Numpy.

For example if you are using OpenCV, you can build an image using numpy taking into account that OpenCV uses BGR representation:

import cv2
import numpy as np

a = np.zeros((100, 100,3))
a[:,:,0] = 255

b = np.zeros((100, 100,3))
b[:,:,1] = 255

c = np.zeros((100, 200,3)) 
c[:,:,2] = 255

img = np.vstack((c, np.hstack((a, b))))

cv2.imshow('image', img)

enter image description here

If you take a look to matrix c you will see it is a 100x200x3 matrix which is exactly what it is shown in the image (in red as we have set the R coordinate to 255 and the other two remain at 0).

Column standard deviation R

If you want to use it with groups, you can use:


  carb      mpg       cyl      disp       hp      drat        wt     qsec        vs        am      gear
1    1 6.001349 0.9759001  75.90037 19.78215 0.5548702 0.6214499 0.590867 0.0000000 0.5345225 0.5345225
2    2 5.472152 2.0655911 122.50499 43.96413 0.6782568 0.8269761 1.967069 0.5270463 0.5163978 0.7888106
3    3 1.053565 0.0000000   0.00000  0.00000 0.0000000 0.1835756 0.305505 0.0000000 0.0000000 0.0000000
4    4 3.911081 1.0327956 132.06337 62.94972 0.4575102 1.0536001 1.394937 0.4216370 0.4830459 0.6992059
5    6       NA        NA        NA       NA        NA        NA       NA        NA        NA        NA
6    8       NA        NA        NA       NA        NA        NA       NA        NA        NA        NA

Should I use != or <> for not equal in T-SQL?

Most databases support != (popular programming languages) and <> (ANSI).

Databases that support both != and <>:

Databases that support the ANSI standard operator, exclusively:

  • IBM DB2 UDB 9.5: <>
  • Microsoft Access 2010: <>

Why should the static field be accessed in a static way?

There's actually a good reason:
The non-static access does not always work, for reasons of ambiguity.

Suppose we have two classes, A and B, the latter being a subclass of A, with static fields with the same name:

public class A {
    public static String VALUE = "Aaa";

public class B extends A {
    public static String VALUE = "Bbb";

Direct access to the static variable:

A.VALUE (="Aaa")
B.VALUE (="Bbb")

Indirect access using an instance (gives a compiler warning that VALUE should be statically accessed):

new B().VALUE (="Bbb")

So far, so good, the compiler can guess which static variable to use, the one on the superclass is somehow farther away, seems somehow logical.

Now to the point where it gets tricky: Interfaces can also have static variables.

public interface C {
    public static String VALUE = "Ccc";

public interface D {
    public static String VALUE = "Ddd";

Let's remove the static variable from B, and observe following situations:

  • B implements C, D
  • B extends A implements C
  • B extends A implements C, D
  • B extends A implements C where A implements D
  • B extends A implements C where C extends D
  • ...

The statement new B().VALUE is now ambiguous, as the compiler cannot decide which static variable was meant, and will report it as an error:

error: reference to VALUE is ambiguous
both variable VALUE in C and variable VALUE in D match

And that's exactly the reason why static variables should be accessed in a static way.

Formatting ISODate from Mongodb

// from MongoDate object to Javascript Date object

var MongoDate = {sec: 1493016016, usec: 650000};
var dt = new Date("1970-01-01T00:00:00+00:00");

How do I find out which computer is the domain controller in Windows programmatically?

To retrieve the information when the DomainController exists in a Domain in which your machine doesn't belong, you need something more.

  DirectoryContext domainContext =  new DirectoryContext(DirectoryContextType.Domain, "targetDomainName", "validUserInDomain", "validUserPassword");

  var domain = System.DirectoryServices.ActiveDirectory.Domain.GetDomain(domainContext);
  var controller = domain.FindDomainController();

Return multiple values in JavaScript?

It is possible to return a string with many values and variables using the template literals `${}`


var newCodes = function() {  
    var dCodes =;
    var dCodes2 =;
    return `${dCodes}, ${dCodes2}`;

It's short and simple.

Where is the correct location to put in an Eclipse project?

I'm finding out that the location of the file depends on the type of Eclipse project.

Specifically, for an Eclipse Dynamic Web Project, most of the answers that involve adding the to the war file do not actually add the properties file in the correct location, especially for Tomcat/Apache.

Here is some of my research and my solution to the issue (again specifically for a Dynamic Web Project running on Tomcat/Apache 6.0)

  • Please refer to this article around how Tomcat will load classes. It's different than the normal class loader for Java. ( Note that it only looks in two places in the war file, WEB-INF/classes and WEB-INF/lib.

  • Note that with a Dynamic Web Project, it is not wise to store your .properties file in the build/../classes directory, as this directory is wiped whenever you clean-build your project.

  • Tomcat does not handle .property files in the WEB-INF/lib location.

  • You cannot store the file in the src directory, as Eclipse abstracts that directory away from your view.

  • The one way I have found to resolve this is to alter the build and add an additional directory that will eventually load into the WEB-INF/classes directory in the war file. Specifically....

(1) Right click your project in the project explorer, select 'New'->'Folder'. You can name the folder anything, but the standard in this case is 'resources'. The new folder should appear at the root level of your project.

(2) Move the file into this new folder.

(3) Right click the project again, and select 'Build-Path'->'Configure Build Path'. Select the 'Sources' tab. Click the 'Add Folder' button. Browse to find your new folder you created in step (1) above. Select 'OK'.

(4) Once back to the eclipse Project Explorer view, note that the folder has now moved to the 'Java Resources' area (ie it's no longer at the root due to eclipse presentation abstraction).

(5) Clean build your project.

(6) To validate that the .properties file now exists in WEB-INF/classes in your war file, export a war file to an easy location (right click Project -> Export -> War file) and checkout the contents. Note that the file now appears in the WEB-INF/classes.

(7) Promote your project to Tomcat/Apache and note that log4j now works.

Now that log4j works, start logging, solve world problems, take some time off, and enjoy a tasty adult beverage.

Regex for string contains?

I'm a few years late, but why not this?


How to make an embedded video not autoplay

I had the same problem and came across this post. Nothing worked. After randomly playing around, I found that <embed ........ play="false"> stopped it from playing automatically. I now have the problem that I can't get a controller to appear, so can't start the movie! :S

Execute combine multiple Linux commands in one line

To run them all at once, you can use the pipe line key "|" like so:

$ cd /my_folder | rm *.jar | svn co path to repo | mvn compile package install

Set element focus in angular way

You can try


for eg.


its working for me.

mssql '5 (Access is denied.)' error during restoring database

The account does not have access to the location for backup file. Take the following steps to access the SQL Server Configuration Manager via Computer Manager easily

  1. Click the Windows key + R to open the Run window.
  2. Type compmgmt.msc in the Open: box.
  3. Click OK.
  4. Expand Services and Applications.
  5. Expand SQL Server Configuration Manager.
  6. Change User Account in Log On As tab .

Now you can Restore Data Base easily

Number of occurrences of a character in a string

Here is the most inefficient way to get the count in all answers. But you'll get a Dictionary that contains key-value pairs as a bonus.

string test = "key1=value1&key2=value2&key3=value3";

var keyValues = Regex.Matches(test, @"([\w\d]+)=([\w\d]+)[&$]*")
                     .ToDictionary(m => m.Groups[1].Value, m => m.Groups[2].Value);

var count = keyValues.Count - 1;

How to run ssh-add on windows?

If you are trying to setup a key for using git with ssh, there's always an option to add a configuration for the identity file.

vi ~/.ssh/config

IdentityFile ~/.ssh/example_key

How to fix Error: "Could not find schema information for the attribute/element" by creating schema

This error occurs when your project references out of date schemas. Use Visual Studio to generate new ones.

In Visual Studio, do the following:

  1. Open your app.config or web.config file.
  2. Go to the XML menu and select Create Schema.

This will trigger app#.xsd (Windows app) or web#.xsd (Website) file(s) to generate.

  1. Save the newly generated xsd file(s) to the root of the project.
    • Open up your App.config or web.config file, right-click in the text-editor and select properties and click the ... button next to the value for Schemas.
    • Add the newly generated xsd file(s) using the Add button.
    • Click OK

The Could not find schema information for the attribute/element error(s) should now be resolved.

Linking dll in Visual Studio

On Windows you do not link with a .dll file directly – you must use the accompanying .lib file instead. To do that go to Project -> Properties -> Configuration Properties -> Linker -> Additional Dependencies and add path to your .lib as a next line.

You also must make sure that the .dll file is either in the directory contained by the %PATH% environment variable or that its copy is in Output Directory (by default, this is Debug\Release under your project's folder).

If you don't have access to the .lib file, one alternative is to load the .dll manually during runtime using WINAPI functions such as LoadLibrary and GetProcAddress.

Solving Quadratic Equation

This line is causing problems:


x/2*a is interpreted as (x/2)*a. You need more parentheses:

(-b + math.sqrt(b**2 - 4*a*c)) / (2 * a)

Also, if you're already storing d, why not use it?

x = (-b + math.sqrt(d)) / (2 * a)

Styling an input type="file" button

Styling file inputs are notoriously difficult, as most browsers will not change the appearance from either CSS or javascript.

Even the size of the input will not respond to the likes of:

<input type="file" style="width:200px">

Instead, you will need to use the size attribute:

<input type="file" size="60" />

For any styling more sophisticated than that (e.g. changing the look of the browse button) you will need to look at the tricksy approach of overlaying a styled button and input box on top of the native file input. The article already mentioned by rm at is the best one I've seen.


Although it's difficult to style an <input> tag directly, this is easily possible with the help of a <label> tag. See answer below from @JoshCrozier:

How to create a box when mouse over text in pure CSS?

You can write like this:


    background: none repeat scroll 0 0 #F8F8F8;
    border: 5px solid #DFDFDF;
    color: #717171;
    font-size: 13px;
    height: 30px;
    letter-spacing: 1px;
    line-height: 30px;
    margin: 0 auto;
    position: relative;
    text-align: center;
    text-transform: uppercase;
    top: -80px;
    padding:0 20px;

    border-bottom:5px solid #dfdfdf;
    border-right:5px solid #dfdfdf;

p:hover span{


<p>Hover here<span>some text here ?</span></p>

Check this

"You may need an appropriate loader to handle this file type" with Webpack and Babel

Due to updates and changes overtime, version compatibility start causing issues with configuration.

Your webpack.config.js should be like this you can also configure how ever you dim fit.

var path = require('path');
var webpack = require("webpack");

module.exports = {
  entry: './src/js/app.js',
  devtool: 'source-map',
    mode: 'development',
  module: {
    rules: [{
      test: /\.js$/,
      exclude: /node_modules/,
      use: ["babel-loader"]
      test: /\.css$/,
      use: ['style-loader', 'css-loader']
  output: {
    path: path.resolve(__dirname, './src/vendor'),
    filename: 'bundle.min.js'

Another Thing to notice it's the change of args, you should read babel documentation


    "presets": ["@babel/preset-env", "@babel/preset-react"]

NB: you have to make sure you have the above @babel/preset-env & @babel/preset-react installed in your package.json dependencies

How can I format a list to print each element on a separate line in python?

Use str.join:

In [27]: mylist = ['10', '12', '14']

In [28]: print '\n'.join(mylist)

How to handle query parameters in angular 2

This worked for me (as of Angular 2.1.0):

constructor(private route: ActivatedRoute) {}
ngOnInit() {
  // Capture the token  if available
  this.sessionId = this.route.snapshot.queryParams['token']


How to insert 1000 rows at a time

Simplest way.

Just stop execution in 10 sec.

Create table SQL_test  ( ID INT IDENTITY(1,1), UserName varchar(100)) 
while 1=1 
insert into SQL_test values ('TEST') 

Printing column separated by comma using Awk command line

Try this awk

awk -F, '{$0=$3}1' file
  • , Divide fields by ,
  • $0=$3 Set the line to only field 3
  • 1 Print all out. (explained here)

This could also be used:

awk -F, '{print $3}' file

Real differences between "java -server" and "java -client"?

I've not noticed any difference in startup time between the 2, but clocked a very minimal improvement in application performance with "-server" (Solaris server, everyone using SunRays to run the app). That was under 1.5.

Temporary table in SQL server causing ' There is already an object named' error

You are dropping it, then creating it, then trying to create it again by using SELECT INTO. Change to:



In MS SQL Server you can create a table without a CREATE TABLE statement by using SELECT INTO

PostgreSQL: days/months/years between two dates

This question is full of misunderstandings. First lets understand the question fully. The asker wants to get the same result as for when running the MS SQL Server function DATEDIFF ( datepart , startdate , enddate ) where datepart takes dd, mm, or yy.

This function is defined by:

This function returns the count (as a signed integer value) of the specified datepart boundaries crossed between the specified startdate and enddate.

That means how many day boundaries, month boundaries, or year boundaries, are crossed. Not how many days, months, or years it is between them. That's why datediff(yy, '2010-04-01', '2012-03-05') is 2, and not 1. There is less than 2 years between those dates, meaning only 1 whole year has passed, but 2 year boundaries have crossed, from 2010 to 2011, and from 2011 to 2012.

The following are my best attempt at replicating the logic correctly.

-- datediff(dd`, '2010-04-01', '2012-03-05') = 704 // 704 changes of day in this interval
select ('2012-03-05'::date - '2010-04-01'::date );
-- 704 changes of day

-- datediff(mm, '2010-04-01', '2012-03-05') = 23  // 23 changes of month
select (date_part('year', '2012-03-05'::date) - date_part('year', '2010-04-01'::date)) * 12 + date_part('month', '2012-03-05'::date) - date_part('month', '2010-04-01'::date)
-- 23 changes of month

-- datediff(yy, '2010-04-01', '2012-03-05') = 2   // 2 changes of year
select date_part('year', '2012-03-05'::date) - date_part('year', '2010-04-01'::date);
-- 2 changes of year

How can I prevent the backspace key from navigating back?

A much neater solution -

$(document).on('keydown', function (e) {
    var key = e == null ? event.keyCode : e.keyCode;
    if(key == 8 && $(':not(:input)')))   //select, textarea

Alternately, you could only check if


How to convert an Image to base64 string in java?

I think you might want:

String encodedFile = Base64.getEncoder().encodeToString(bytes);

How to Load RSA Private Key From File

Two things. First, you must base64 decode the mykey.pem file yourself. Second, the openssl private key format is specified in PKCS#1 as the RSAPrivateKey ASN.1 structure. It is not compatible with java's PKCS8EncodedKeySpec, which is based on the SubjectPublicKeyInfo ASN.1 structure. If you are willing to use the bouncycastle library you can use a few classes in the bouncycastle provider and bouncycastle PKIX libraries to make quick work of this.


import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openssl.PEMKeyPair;
import org.bouncycastle.openssl.PEMParser;
import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter;

// ...   

String keyPath = "mykey.pem";
BufferedReader br = new BufferedReader(new FileReader(keyPath));
Security.addProvider(new BouncyCastleProvider());
PEMParser pp = new PEMParser(br);
PEMKeyPair pemKeyPair = (PEMKeyPair) pp.readObject();
KeyPair kp = new JcaPEMKeyConverter().getKeyPair(pemKeyPair);
samlResponse.sign(Signature.getInstance("SHA1withRSA").toString(), kp.getPrivate(), certs);

laravel foreach loop in controller

Hi, this will throw an error:

foreach ($product->sku as $sku){ 
// Code Here

because you cannot loop a model with a specific column ($product->sku) from the table.
So you must loop on the whole model:

foreach ($product as $p) {
// code

Inside the loop you can retrieve whatever column you want just adding "->[column_name]"

foreach ($product as $p) {
echo $p->sku;

Have a great day

Recommended way to get hostname in Java

The most portable way to get the hostname of the current computer in Java is as follows:


public class getHostName {

    public static void main(String[] args) throws UnknownHostException {
        InetAddress iAddress = InetAddress.getLocalHost();
        String hostName = iAddress.getHostName();
        //To get  the Canonical host name
        String canonicalHostName = iAddress.getCanonicalHostName();

        System.out.println("HostName:" + hostName);
        System.out.println("Canonical Host Name:" + canonicalHostName);

How to prepend a string to a column value in MySQL?

Many string update functions in MySQL seems to be working like this: If one argument is null, then concatenation or other functions return null too. So, to update a field with null value, first set it to a non-null value, such as ''

For example:

update table set field='' where field is null;
update table set field=concat(field,' append');

C# get and set properties for a List Collection

It would be inappropriate for it to be part of the setter - it's not like you're really setting the whole list of strings - you're just trying to add one.

There are a few options:

  • Put AddSubheading and AddContent methods in your class, and only expose read-only versions of the lists
  • Expose the mutable lists just with getters, and let callers add to them
  • Give up all hope of encapsulation, and just make them read/write properties

In the second case, your code can be just:

public class Section
    public String Head { get; set; }
    private readonly List<string> _subHead = new List<string>();
    private readonly List<string> _content = new List<string>();

    // Note: fix to case to conform with .NET naming conventions
    public IList<string> SubHead { get { return _subHead; } }
    public IList<string> Content { get { return _content; } }

This is reasonably pragmatic code, although it does mean that callers can mutate your collections any way they want, which might not be ideal. The first approach keeps the most control (only your code ever sees the mutable list) but may not be as convenient for callers.

Making the setter of a collection type actually just add a single element to an existing collection is neither feasible nor would it be pleasant, so I'd advise you to just give up on that idea.

Set space between divs

You need a gutter between two div gutter can be made as following

margin(gutter) = width - gutter size E.g margin = calc(70% - 2em)

<body bgcolor="gray">
<section id="main">
        <div id="left">
            Something here     
        <div id="right">
                Someone there
    font-size: 10px;

#main div{
    float: left;
    width: calc(50% - 1.5em);
    margin-left: 1.5em;

How can I open a website in my web browser using Python?

import webbrowser"")

The link will be opened in default web browser unless specified

How to hide/show div tags using JavaScript?

You can Hide/Show Div using Js function. sample below

        function showDivAttid(){

            if(Your Condition)
             document.getElementById("attid").style.display = 'inline';
            document.getElementById("attid").style.display = 'none';



HTML - Show/Hide this text

jQuery-- Populate select from json

I just used the javascript console in Chrome to do this. I replaced some of your stuff with placeholders.

var temp= ['one', 'two', 'three']; //'${temp}';
var $select = $('<select>'); //$('#down');                        
$.each(temp, function(key, value) {              


<option value="0">one</option><option value="1">two</option><option value="2">three</option>

However it looks like your json is probably actually a string because the following will end up doing what you describe. So make your JSON actual JSON not a string.

var temp= "['one', 'two', 'three']"; //'${temp}';
var $select = $('<select>'); //$('#down');                        
$.each(temp, function(key, value) {              

Convert date yyyyMMdd to system.datetime format

string time = "19851231";
DateTime theTime= DateTime.ParseExact(time,

HTML5 placeholder css padding

I found the answer that remedied my frustrations regarding this on John Catterfeld's blog.

... Chrome (v20-30) implements almost all styles but with a major caveat – the placeholder styles do no resize the input box, so stay clear of things like line-height and padding top or bottom.

If you are using line-height or padding you are going to be frustrated with the resulting placeholder. I haven't found a way around that up to this point.

Directory.GetFiles: how to get only filename, not full path?

Use this to obtain only the filename.


JSONDecodeError: Expecting value: line 1 column 1 (char 0)

There may be embedded 0's, even after calling decode(). Use replace():

import json
struct = {}
    response_json = response_json.decode('utf-8').replace('\0', '')
    struct = json.loads(response_json)
    print('bad json: ', response_json)
return struct

Why use $_SERVER['PHP_SELF'] instead of ""

I know that the question is two years old, but it was the first result of what I am looking for. I found a good answers and I hope I can help other users.

Look at this

I will make this brief:

  • use the $_SERVER["PHP_SELF"] Variable with htmlspecialchars():

  • PHP_SELF returns the filename of the currently executing script.

  • The htmlspecialchars() function converts special characters to HTML entities. --> NO XSS

How can I INSERT data into two tables simultaneously in SQL Server?

I was also struggling with this problem, and find that the best way is to use a CURSOR.

I have tried Denis solution with OUTPUT, but as he mentiond, it's impossible to output external columns in an insert statement, and the MERGE can't work when insert multiple rows by select.

So, i've used a CURSOR, for each row in the outer table, i've done a INSERT, then use the @@IDENTITY for another INSERT.

DECLARE @OuterID int

SELECT  ID FROM   [external_Table]


INSERT INTO [Table]   (data)
    SELECT data
    FROM     [external_Table] where ID = @OuterID 

    INSERT INTO [second_table] (FK,OuterID)


How do I raise the same Exception with a custom message in Python?

This is the function I use to modify the exception message in Python 2.7 and 3.x while preserving the original traceback. It requires six

def reraise_modify(caught_exc, append_msg, prepend=False):
    """Append message to exception while preserving attributes.

    Preserves exception class, and exception traceback.

        This function needs to be called inside an except because
        `sys.exc_info()` requires the exception context.

        caught_exc(Exception): The caught exception object
        append_msg(str): The message to append to the caught exception
        prepend(bool): If True prepend the message to args instead of appending


    Side Effects:
        Re-raises the exception with the preserved data / trace but
        modified message
    ExceptClass = type(caught_exc)
    # Keep old traceback
    traceback = sys.exc_info()[2]
    if not caught_exc.args:
        # If no args, create our own tuple
        arg_list = [append_msg]
        # Take the last arg
        # If it is a string
        # append your message.
        # Otherwise append it to the
        # arg list(Not as pretty)
        arg_list = list(caught_exc.args[:-1])
        last_arg = caught_exc.args[-1]
        if isinstance(last_arg, str):
            if prepend:
                arg_list.append(append_msg + last_arg)
                arg_list.append(last_arg + append_msg)
            arg_list += [last_arg, append_msg]
    caught_exc.args = tuple(arg_list)

Setting up and using environment variables in IntelliJ Idea

In addition to the above answer and restarting the IDE didn't do, try restarting "Jetbrains Toolbox" if you use it, this did it for me

How do I add an image to a JButton

For example if you have image in folder res/image.png you can write:

    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
    InputStream input = classLoader.getResourceAsStream("image.png");
    // URL input = classLoader.getResource("image.png"); // <-- You can use URL class too.
    BufferedImage image =;

    button.setIcon(new ImageIcon(image));
catch(IOException e)

In one line:

    button.setIcon(new ImageIcon("image.png"))));
catch(IOException e)

If the image is bigger than button then it will not shown.

Add text to Existing PDF using Python

Example for [Python 2.7]:

from pyPdf import PdfFileWriter, PdfFileReader
import StringIO
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter

packet = StringIO.StringIO()
# create a new PDF with Reportlab
can = canvas.Canvas(packet, pagesize=letter)
can.drawString(10, 100, "Hello world")

#move to the beginning of the StringIO buffer
new_pdf = PdfFileReader(packet)
# read your existing PDF
existing_pdf = PdfFileReader(file("original.pdf", "rb"))
output = PdfFileWriter()
# add the "watermark" (which is the new pdf) on the existing page
page = existing_pdf.getPage(0)
# finally, write "output" to a real file
outputStream = file("destination.pdf", "wb")

Example for Python 3.x:

from PyPDF2 import PdfFileWriter, PdfFileReader
import io
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter

packet = io.BytesIO()
# create a new PDF with Reportlab
can = canvas.Canvas(packet, pagesize=letter)
can.drawString(10, 100, "Hello world")

#move to the beginning of the StringIO buffer
new_pdf = PdfFileReader(packet)
# read your existing PDF
existing_pdf = PdfFileReader(open("original.pdf", "rb"))
output = PdfFileWriter()
# add the "watermark" (which is the new pdf) on the existing page
page = existing_pdf.getPage(0)
# finally, write "output" to a real file
outputStream = open("destination.pdf", "wb")

How to initialise a string from NSData in Swift

This is how you should initialize the NSString:

Swift 2.X or older

let datastring = NSString(data: fooData, encoding: NSUTF8StringEncoding)

Swift 3 or newer:

let datastring = NSString(data: fooData, encoding: String.Encoding.utf8.rawValue)

This doc explains the syntax.

Postgresql: password authentication failed for user "postgres"

Answer given is almost correct just missing some pointers which i'll be taking care of in my solution

First make sure your user have a sudo access if not you can use the below command to add your user as sudo user :-

sudo adduser <username> sudo

The change will take effect the next time the user logs in.

i) Now go to sudo vim /etc/postgresql/<your_postgres_version>/main/pg_hba.conf file and look for line that says :

local   all             postgres                                md5 #peer

and comment that. Just below that line there must be a commented line that says:

local   all             postgres                                peer

or for older versions it'll be :-

local   all         postgres                          ident

Uncomment that line.

ii) Now restart the postgres by using any of these commands :-

sudo /etc/init.d/postgresql restart


sudo service postgresql restart

iii) Now you can simply log into postgres using the following command :

sudo -u postgres psql

iv) once you're in you can create any operation you want to in my case i wanted to create a new database you can do the same using below command :

CREATE DATABASE airflow_replica;

Adjust UILabel height to text

Swift 4.0

self.messageLabel = UILabel(frame: CGRect(x: 70, y: 60, width:UIScreen.main.bounds.width - 80, height: 30)

messageLabel.text = message

messageLabel.lineBreakMode = .byWordWrapping //in versions below swift 3 (messageLabel.lineBreakMode = NSLineBreakMode.ByWordWrapping)    
messageLabel.numberOfLines = 0 //To write any number of lines within a label scope

messageLabel.textAlignment = .center

messageLabel.textColor = UIColor.white

messageLabel.font = messageLabel.font.withSize(12)


Blockquote NSParagraphStyle.LineBreakMode, apply to entire paragraphs, not words within paragraphs.This property is in effect both during normal drawing and in cases where the font size must be reduced to fit the label’s text in its bounding box. This property is set to byTruncatingTail by default.

This link describes the storyboard way of doing the same

How to insert table values from one database to another database?

You can try

Insert into your_table_in_db1 select * from your_table_in_db2@db2SID 

db2SID is the sid of other DB. It will be present in tnsnames.ora file

invalid use of non-static data member

In C++, nested classes are not connected to any instance of the outer class. If you want bar to access non-static members of foo, then bar needs to have access to an instance of foo. Maybe something like:

class bar {
    int getA(foo & f ) {return foo.a;}

Or maybe

class bar {
    foo & f;

    bar(foo & g)
    : f(g)

    int getA() { return f.a; }

In any case, you need to explicitly make sure you have access to an instance of foo.

How to empty a file using Python

Opening a file creates it and (unless append ('a') is set) overwrites it with emptyness, such as this:

open(filename, 'w').close()

What is the purpose of nameof?

Your question already expresses the purpose. You must see this might be useful for logging or throwing exceptions.

For example:

public void DoStuff(object input)
    if (input == null)
        throw new ArgumentNullException(nameof(input));

This is good. If I change the name of the variable, the code will break instead of returning an exception with an incorrect message.

Of course, the uses are not limited to this simple situation. You can use nameof whenever it would be useful to code the name of a variable or property.

The uses are manifold when you consider various binding and reflection situations. It's an excellent way to bring what were run time errors to compile time.

Instantiating a generic class in Java

Quick solution that worked for me. I see there is already an answer for this and this may not even be the best way to go about it. Also, for my solution you'll need Gson.

However, I ran into a situation where I needed to create an instance of a generic class of type java.lang.reflect.Type.

The following code will create an instance of the class you want with null instance variables.

T object = new Gson().fromJson("{}", myKnownType);

Where myKnownType is known before hand and obtained via TypeToken.getType().

You can now set appropriate properties on this object. Again, this may not be the best way to do this but it works as a quick solution if that's what you need.

Accessing all items in the JToken

In addition to the accepted answer I would like to give an answer that shows how to iterate directly over the Newtonsoft collections. It uses less code and I'm guessing its more efficient as it doesn't involve converting the collections.

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
//Parse the data
JObject my_obj = JsonConvert.DeserializeObject<JObject>(your_json);

foreach (KeyValuePair<string, JToken> sub_obj in (JObject)my_obj["ADDRESS_MAP"])

I started doing this myself because JsonConvert automatically deserializes nested objects as JToken (which are JObject, JValue, or JArray underneath I think).

I think the parsing works according to the following principles:

  • Every object is abstracted as a JToken

  • Cast to JObject where you expect a Dictionary

  • Cast to JValue if the JToken represents a terminal node and is a value

  • Cast to JArray if its an array

  • JValue.Value gives you the .NET type you need

Error loading MySQLdb Module 'Did you install mysqlclient or MySQL-python?'

edit the file in your project origin directory

import pymysql


Why is the minidlna database not being refreshed?

I have recently discovered that minidlna doesn't update the database if the media file is a hardlink. If you want these files to show up in the database, a full rescan is necessary.

ex: If you have a file /home/movies/foo.mkv and a hardlink in /home/minidlna/video/foo.mkv, where '/home/minidlna' is your minidlna share, you will have to do a rescan till that file appears in the db (and subsequently your dlna client).

I'm still trying to find a way around this. If anyone has any input, it's most welcome.

MacOS Xcode CoreSimulator folder very big. Is it ok to delete content?

for Xcode 8:

What I do is run sudo du -khd 1 in the Terminal to see my file system's storage amounts for each folder in simple text, then drill up/down into where the huge GB are hiding using the cd command.

Ultimately you'll find the Users//Library/Developer/CoreSimulator/Devices folder where you can have little concern about deleting all those "devices" using iOS versions you no longer need. It's also safe to just delete them all, but keep in mind you'll lose data that's written to the device like sqlite files you may want to use as a backup version.

I once saved over 50GB doing this since I did so much testing on older iOS versions.

Use multiple custom fonts using @font-face?

I use this method in my css file

@font-face {
  font-family: FontName1;
  src: url("fontname1.eot"); /* IE */
  src: local('FontName1'), url('fontname1.ttf') format('truetype'); /* others */
@font-face {
  font-family: FontName2;
  src: url("fontname1.eot"); /* IE */
  src: local('FontName2'), url('fontname2.ttf') format('truetype'); /* others */
@font-face {
  font-family: FontName3;
  src: url("fontname1.eot"); /* IE */
  src: local('FontName3'), url('fontname3.ttf') format('truetype'); /* others */

How to change environment's font size?

As of mid 2017 To quickly get to the settings files press ctrl + shift + p and enter settings, there you will find the user settings and the workspace settings, be aware that the workspace settings will override the user settings, so it's better to use the latter directly to make it a global change (workspace settings will create a folder in your project root), from there you will have the option to add the option "editor.fontSize": 14 to your settings as a quick suggestion, but you can do it yourself and change the value to your preferred font size.

To sum it up:

  1. ctrl + shift + p

  2. select "user settings"

  3. add "editor.fontSize": 14

sqlalchemy filter multiple columns

You can simply call filter multiple times:

query = meta.Session.query(User).filter( \

SOAP vs REST (differences)

Among many others already covered in the many answers, I would highlight that SOAP enables to define a contract, the WSDL, which define the operations supported, complex types, etc. SOAP is oriented to operations, but REST is oriented at resources. Personally I would select SOAP for complex interfaces between internal enterprise applications, and REST for public, simpler, stateless interfaces with the outside world.

enter image description here

Drag and drop elements from list into separate blocks

Dragging an object and placing in a different location is part of the standard of HTML5. All the objects can be draggable. But the Specifications of below web browser should be followed. API Chrome Internet Explorer Firefox Safari Opera Version 4.0 9.0 3.5 6.0 12.0

You can find example from below:

SEVERE: Unable to create initial connections of pool - tomcat 7 with context.xml file

I have also dealt with this exception after a fully working context.xml setup was adjusted. I didn't want environment details in the context.xml, so I took them out and saw this error. I realized I must fully create this datasource resource in code based on System Property JVM -D args.

Original error with just user/pwd/host removed: org.apache.tomcat.jdbc.pool.ConnectionPool init SEVERE: Unable to create initial connections of pool.

Removed entire contents of context.xml and try this: Initialize on startup of app server the datasource object sometime before using first connection. If using Spring this is good to do in an @Configuration bean in @Bean Datasource constructor.

package to use: org.apache.tomcat.jdbc.pool.*

PoolProperties p = new PoolProperties();
            p.setValidationQuery("SELECT 1");
            org.apache.tomcat.jdbc.pool.DataSource ds = new org.apache.tomcat.jdbc.pool.DataSource();
            return ds;

Heroku: How to push different local Git branches to Heroku/master

Also note that if your using the git flow system and your feature branch might be called


and with a git remote called stagingtwo, then the command to push to heroku would be

git push stagingtwo feature/mobile_additions:master

How to view log output using docker-compose run?

If you want to see output logs from all the services in your terminal.

docker-compose logs -t -f --tail <no of lines> 

Eg.: Say you would like to log output of last 5 lines from all service

docker-compose logs -t -f --tail 5

If you wish to log output from specific services then it can be done as below:

docker-compose logs -t -f --tail <no of lines> <name-of-service1> <name-of-service2> ... <name-of-service N>


Eg. say you have API and portal services then you can do something like below :

docker-compose logs -t -f --tail 5 portal api

Where 5 represents last 5 lines from both logs.


How to split a data frame?

You may also want to cut the data frame into an arbitrary number of smaller dataframes. Here, we cut into two dataframes.

x = data.frame(num = 1:26, let = letters, LET = LETTERS)
split(x, sample(rep(1:2, 13)))


   num let LET
3    3   c   C
6    6   f   F
10  10   j   J
12  12   l   L
14  14   n   N
15  15   o   O
17  17   q   Q
18  18   r   R
20  20   t   T
21  21   u   U
22  22   v   V
23  23   w   W
26  26   z   Z

   num let LET
1    1   a   A
2    2   b   B
4    4   d   D
5    5   e   E
7    7   g   G
8    8   h   H
9    9   i   I
11  11   k   K
13  13   m   M
16  16   p   P
19  19   s   S
24  24   x   X
25  25   y   Y

You can also split a data frame based upon an existing column. For example, to create three data frames based on the cyl column in mtcars: