Programs & Examples On #Web safe fonts

PHP: date function to get month of the current date

To compare with an int do this:

$date = date("m");
$dateToCompareTo = 05;
if (strval($date) == strval($dateToCompareTo)) {
    echo "They are the same";

Counting number of words in a file

3 steps: Consume all the white spaces, check if is a line, consume all the nonwhitespace.3

    c =;                
    // consume whitespaces
    while(isspace(c)){ }
    if (c == '\n'){ numberLines++; continue; }
    while (!isspace(c)){
         c =;

How to implement if-else statement in XSLT?

If statement is used for checking just one condition quickly. When you have multiple options, use <xsl:choose> as illustrated below:

     <xsl:when test="$CreatedDate > $IDAppendedDate">

Also, you can use multiple <xsl:when> tags to express If .. Else If or Switch patterns as illustrated below:

     <xsl:when test="$CreatedDate > $IDAppendedDate">
     <xsl:when test="$CreatedDate = $IDAppendedDate">

The previous example would be equivalent to the pseudocode below:

   if ($CreatedDate > $IDAppendedDate)
       output: <h2>mooooooooooooo</h2>
   else if ($CreatedDate = $IDAppendedDate)
       output: <h2>booooooooooooo</h2>
       output: <h2>dooooooooooooo</h2>

WCF service startup error "This collection already contains an address with scheme http"

In .Net 4, you can use the multipleSiteBindingsEnabled option:

    <serviceHostingEnvironment multipleSiteBindingsEnabled="true">

Then, you won't have to specify each address.

PHP check if url parameter exists

    // Do something

You want something like that

Expected corresponding JSX closing tag for input Reactjs

You need to close the input element with /> at the end. In React, we have to close every element. Your code should be:

<input id="icon_prefix" type="text" class="validate/">

How to set JAVA_HOME path on Ubuntu?

add JAVA_HOME to the file:


for it to be available to the entire system (you would need to restart Ubuntu though)

Navigation Controller Push View Controller

Use this code in your button action (Swift 3.0.1):

let vc = self.storyboard?.instantiateViewController(
    withIdentifier: "YourSecondVCIdentifier") as! SecondVC

navigationController?.pushViewController(vc, animated: true)

Best/Most Comprehensive API for Stocks/Financial Data

I usually find that ProgrammableWeb is a good place to go when looking for APIs.

How to use a findBy method with comparative criteria

You have to use either DQL or the QueryBuilder. E.g. in your Purchase-EntityRepository you could do something like this:

$q = $this->createQueryBuilder('p')
          ->where('p.prize > :purchasePrize')
          ->setParameter('purchasePrize', 200)


For even more complex scenarios take a look at the Expr() class.

identifier "string" undefined?

<string.h> is the old C header. C++ provides <string>, and then it should be referred to as std::string.

Is Java's assertEquals method reliable?

"The == operator checks to see if two Objects are exactly the same Object."

String is an Object in java, so it falls into that category of comparison rules.

jQuery add image inside of div tag

var img;
for (var i = 0; i < jQuery('.MulImage').length; i++) {
                var imgsrc = jQuery('.MulImage')[i];
                var CurrentImgSrc = imgsrc.src;
                img = jQuery('<img class="dynamic" style="width:100%;">');
                img.attr('src', CurrentImgSrc);


NoClassDefFoundError in Java: com/google/common/base/Function

this is for chrome  
driver =new ChromeDriver();
this is for fire fox 
driver =new FirefoxDriver();

pattern :

System.setProperty("webdriver.gecko.driver","**Path of the gecko driver** ");

Note download gecko from here :-

Python: How to convert datetime format?

>>> import datetime
>>> d = datetime.datetime.strptime('2011-06-09', '%Y-%m-%d')
>>> d.strftime('%b %d,%Y')
'Jun 09,2011'

In pre-2.5 Python, you can replace datetime.strptime with time.strptime, like so (untested): datetime.datetime(*(time.strptime('2011-06-09', '%Y-%m-%d')[0:6]))

Best method to download image from url in Android

I recommend using the altex-image-downloader library, which makes it easy to download images:

AltexImageDownloader.writeToDisk(context, Imageurl, "IMAGES");

Add dependency in app build gradle:

implementation 'com.artjimlop:altex-image-downloader:0.0.4'

Comparing strings in C# with OR in an if statement


if (testString.Equals(testString2)){

Python For loop get index

Do you want to iterate over characters or words?

For words, you'll have to split the words first, such as

for index, word in enumerate(loopme.split(" ")):
    print "CURRENT WORD IS", word, "AT INDEX", index

This prints the index of the word.

For the absolute character position you'd need something like

chars = 0
for index, word in enumerate(loopme.split(" ")):
    print "CURRENT WORD IS", word, "AT INDEX", index, "AND AT CHARACTER", chars
    chars += len(word) + 1

Visual Studio Code pylint: Unable to import 'protorpc'

I was still getting these errors even after confirming that the correct python and pylint were being used from my virtual env.

Eventually I figured out that in Visual Studio Code I was A) opening my project directory, which is B) where my Python virtual environment was, but I was C) running my main Python program from two levels deeper. Those three things need to be in sync for everything to work.

Here's what I would recommend:

  1. In Visual Studio Code, open the directory containing your main Python program. (This may or may not be the top level of the project directory.)

  2. Select Terminal menu > New Terminal, and create an virtual environment directly inside the same directory.

    python3 -m venv env
  3. Install pylint in the virtual environment. If you select any Python file in the sidebar, Visual Studio Code will offer to do this for you. Alternatively, source env/bin/activate then pip install pylint.

  4. In the blue bottom bar of the editor window, choose the Python interpreter env/bin/python. Alternatively, go to Settings and set "Python: Python Path." This sets python.pythonPath in Settings.json.

What is the difference between Spring, Struts, Hibernate, JavaServer Faces, Tapestry?

Tapestry pages and components are simple POJO's(Plain Old Java Object) consisting of getters and setters for easy access to Java language features.

How to force a hover state with jQuery?

Also, you could try triggering a mouseover.

$("#btn").click(function() {

Not sure if this will work for your specific scenario, but I've had success triggering mouseover instead of hover for various cases.

cordova run with ios error .. Error code 65 for command: xcodebuild with args:

How to do what @connor said:


  • Open platforms/ios on XCode
  • Find & Replace io.ionic.starter in all files for a unique identifier
  • Click the project to open settings
  • Signing > Select a team
  • Go to your device Settings > General > DeviceManagement
    • Trust your account/team
  • ionic cordova run ios --device --livereload

How to save data in an android app

  1. Shared preferences: android shared preferences example for high scores?

  2. Does your application has an access to the "external Storage Media". If it does then you can simply write the value (store it with timestamp) in a file and save it. The timestamp will help you in showing progress if thats what you are looking for. {not a smart solution.}

-bash: export: `=': not a valid identifier

I faced the same error and did some research to only see that there could be different scenarios to this error. Let me share my findings.

Scenario 1: There cannot be spaces beside the = (equals) sign

$ export TEMP_ENV = example-value
-bash: export: `=': not a valid identifier
// this is the answer to the question

$ export TEMP_ENV =example-value
-bash: export: `=example-value': not a valid identifier

$ export TEMP_ENV= example-value
-bash: export: `example-value': not a valid identifier

Scenario 2: Object value assignment should not have spaces besides quotes

$ export TEMP_ENV={ "key" : "json example" } 
-bash: export: `:': not a valid identifier
-bash: export: `json example': not a valid identifier
-bash: export: `}': not a valid identifier

Scenario 3: List value assignment should not have spaces between values

$ export TEMP_ENV=[1,2 ,3 ]
-bash: export: `,3': not a valid identifier
-bash: export: `]': not a valid identifier

I'm sharing these, because I was stuck for a couple of hours trying to figure out a workaround. Hopefully, it will help someone in need.

Run PowerShell command from command prompt (no ps1 script)

Run it on a single command line like so:

powershell.exe -ExecutionPolicy Bypass -NoLogo -NonInteractive -NoProfile 
  -WindowStyle Hidden -Command "Get-AppLockerFileInformation -Directory <folderpath> 
  -Recurse -FileType <type>"

What's the difference between console.dir and console.log?

Another useful difference in Chrome exists when sending DOM elements to the console.


  • console.log prints the element in an HTML-like tree
  • console.dir prints the element in a JSON-like tree

Specifically, console.log gives special treatment to DOM elements, whereas console.dir does not. This is often useful when trying to see the full representation of the DOM JS object.

There's more information in the Chrome Console API reference about this and other functions.

Request Permission for Camera and Library in iOS 10 - Info.plist

Swift 5 The easiest way to add permissions without having to do it programatically, is to open your info.plist file and select the + next to Information Property list. Scroll through the drop down list to the Privacy options and select Privacy Camera Usage Description for accessing camera, or Privacy Photo Library Usage Description for accessing the Photo Library. Fill in the String value on the right after you've made your selection, to include the text you would like displayed to your user when the alert pop up asks for permissions. Camera/Photo Library permission

DateDiff to output hours and minutes

If you want 08:30 ( HH:MM) format then try this,

    , EmplName
    , InTime
    , [TimeOut]
    , [DateVisited]
    ,  RIGHT('0' + CONVERT(varchar(3),DATEDIFF(minute,InTime, TimeOut)/60),2) + ':' +
      RIGHT('0' + CONVERT(varchar(2),DATEDIFF(minute,InTime,TimeOut)%60),2)
      as TotalHours from times Order By EmplID, DateVisited

How do I get the picture size with PIL?

Since scipy's imread is deprecated, use imageio.imread.

  1. Install - pip install imageio
  2. Use height, width, channels = imageio.imread(filepath).shape

Error resolving template "index", template might not exist or might not be accessible by any of the configured Template Resolvers

If you are facing this issue and everything looks good, try invalidate cache/restart from your IDE. This will resolve the issue in most of the cases.

How can you create pop up messages in a batch script?

I put together a script based on the good answers here & in other posts

You can set title timeout & even sleep to schedule it for latter & \n for new line

also you get back the key press into a variable (%pop.key%).

Here is my code

How to unlock android phone through ADB

Another way just for your information.

Use an USB OTG cable and connect with an USB mouse, you can touch the screen by clicking your mouse !

Converting an integer to a hexadecimal string in Ruby

To summarize:

p 10.to_s(16) #=> "a"
p "%x" % 10 #=> "a"
p "%02X" % 10 #=> "0A"
p sprintf("%02X", 10) #=> "0A"
p "#%02X%02X%02X" % [255, 0, 10] #=> "#FF000A"

Regular expression to limit number of characters to 10

pattern: /[\w\W]{1,10}/g

I used this expression for my case, it includes all the characters available in the text.

Removing specific rows from a dataframe

One simple solution:

cond1 <- df$sub == 1 & df$day == 2

cond2 <- df$sub == 3 & df$day == 4

df <- df[!(cond1 | cond2),]

How to set iPhone UIView z index?

You can use the zPosition property of the view's layer (it's a CALayer object) to change the z-index of the view.

theView.layer.zPosition = 1;

As Viktor Nordling added, "big values are on top. You can use any values you want, including negative values." The default value is 0.

You need to import the QuartzCore framework to access the layer. Just add this line of code at the top of your implementation file.

#import "QuartzCore/QuartzCore.h"

python: how to get information about a function?



to get built-in help messages.

Strip HTML from Text JavaScript

I have created a working regular expression myself:

str=str.replace(/(<\?[a-z]*(\s[^>]*)?\?(>|$)|<!\[[a-z]*\[|\]\]>|<!DOCTYPE[^>]*?(>|$)|<!--[\s\S]*?(-->|$)|<[a-z?!\/]([a-z0-9_:.])*(\s[^>]*)?(>|$))/gi, ''); 

Android: Align button to bottom-right of screen using FrameLayout?

If you want to try with java code. Here you go -

    final LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT, 
    params.gravity = Gravity.BOTTOM; // set gravity

How to use XPath preceding-sibling correctly

You don't need to go level up and use .. since all buttons are on the same level:

//button[contains(.,'Arcade Reader')]/preceding-sibling::button[@name='settings']

How to shrink temp tablespace in oracle?

You should have written what version of Oracle you use. You most likely use something else than Oracle 11g, that's why you can't shrink a temp tablespace.


1) alter database tempfile '[your_file]' resize 128M; which will probably fail
2) Drop and recreate the tablespace. If the temporary tablespace you want to shrink is your default temporary tablespace, you may have to first create a new temporary tablespace, set it as the default temporary tablespace then drop your old default temporary tablespace and recreate it. Afterwards drop the second temporary table created. 3) For Oracle 9i and higher you could just drop the tempfile(s) and add a new one(s)

Everything is described here in great detail.

See this link:
It was already linked, but maybe you missed it, so here it is again.

JS map return object

map rockets and add 10 to its launches:

var rockets = [_x000D_
    { country:'Russia', launches:32 },_x000D_
    { country:'US', launches:23 },_x000D_
    { country:'China', launches:16 },_x000D_
    { country:'Europe(ESA)', launches:7 },_x000D_
    { country:'India', launches:4 },_x000D_
    { country:'Japan', launches:3 }_x000D_
];_x000D_ => {_x000D_
    itm.launches += 10_x000D_
    return itm_x000D_

If you don't want to modify rockets you can do:

var plusTen = []
rockets.forEach((itm) => {
    plusTen.push({'country':, 'launches': itm.launches + 10})

How to temporarily disable a click handler in jQuery?

If #button_id implies a standard HTML button (like a submit button) you can use the 'disabled' attribute to make the button inactive to the browser.

$("#button_id").click(function() {
    $('#button_id').attr('disabled', 'true');

    //do something


What you may need to be careful with, however, is the order in which these things may happen. If you are using the jquery hide command, you may want to include the "$('#button_id').removeAttr('disabled');" as part of a call back, so that it does not happen until the hide is complete.

[edit] example of function using a callback:

$("#button_id").click(function() {
    $('#button_id').attr('disabled', 'true');
    $('#myDiv').hide(function() { $('#button_id').removeAttr('disabled'); });

How to fix: /usr/lib/ version `GLIBCXX_3.4.15' not found

I fixed this issue by installing: sudo apt-get install libstdc++6

In my case, I ran into this issue after installing MongoDB 3.0.1

mongo: /usr/lib/x86_64-linux-gnu/ version `GLIBCXX_3.4.18' not found (required by mongo)

Timer Interval 1000 != 1 second?

The proper interval to get one second is 1000. The Interval property is the time between ticks in milliseconds:

MSDN: Timer.Interval Property

So, it's not the interval that you set that is wrong. Check the rest of your code for something like changing the interval of the timer, or binding the Tick event multiple times.

How can I slice an ArrayList out of an ArrayList in Java?

I have found a way if you know startIndex and endIndex of the elements one need to remove from ArrayList

Let al be the original ArrayList and startIndex,endIndex be start and end index to be removed from the array respectively:

al.subList(startIndex, endIndex + 1).clear();

MongoDB: update every document on one field

I have been using MongoDB .NET driver for a little over a month now. If I were to do it using .NET driver, I would use Update method on the collection object. First, I will construct a query that will get me all the documents I am interested in and do an Update on the fields I want to change. Update in Mongo only affects the first document and to update all documents resulting from the query one needs to use 'Multi' update flag. Sample code follows...

var collection = db.GetCollection("Foo");
var query = Query.GTE("No", 1); // need to construct in such a way that it will give all 20K //docs.
var update = Update.Set("timestamp", datetime.UtcNow);
collection.Update(query, update, UpdateFlags.Multi);

What's the difference between an element and a node in XML?

A node is defined as:

the smallest unit of a valid, complete structure in a document.

or as:

An object in the tree view that serves as a container to hold related objects.

Now their are many different kinds of nodes as an elements node, an attribute node etc.

Docker - Ubuntu - bash: ping: command not found

Alternatively you can use a Docker image which already has ping installed, e.g. busybox:

docker run --rm busybox ping SERVER_NAME -c 2

Meaning of numbers in "col-md-4"," col-xs-1", "col-lg-2" in Bootstrap

Applies to Bootstrap 3 only.

Ignoring the letters (xs, sm, md, lg) for now, I'll start with just the numbers...

  • the numbers (1-12) represent a portion of the total width of any div
  • all divs are divided into 12 columns
  • so, col-*-6 spans 6 of 12 columns (half the width), col-*-12 spans 12 of 12 columns (the entire width), etc

So, if you want two equal columns to span a div, write

<div class="col-xs-6">Column 1</div>
<div class="col-xs-6">Column 2</div>

Or, if you want three unequal columns to span that same width, you could write:

<div class="col-xs-2">Column 1</div>
<div class="col-xs-6">Column 2</div>
<div class="col-xs-4">Column 3</div>

You'll notice the # of columns always add up to 12. It can be less than twelve, but beware if more than 12, as your offending divs will bump down to the next row (not .row, which is another story altogether).

You can also nest columns within columns, (best with a .row wrapper around them) such as:

<div class="col-xs-6">
  <div class="row">
    <div class="col-xs-4">Column 1-a</div>
    <div class="col-xs-8">Column 1-b</div>
<div class="col-xs-6">
  <div class="row">
    <div class="col-xs-2">Column 2-a</div>
    <div class="col-xs-10">Column 2-b</div>

Each set of nested divs also span up to 12 columns of their parent div. NOTE: Since each .col class has 15px padding on either side, you should usually wrap nested columns in a .row, which has -15px margins. This avoids duplicating the padding and keeps the content lined up between nested and non-nested col classes.

-- You didn't specifically ask about the xs, sm, md, lg usage, but they go hand-in-hand so I can't help but touch on it...

In short, they are used to define at which screen size that class should apply:

  • xs = extra small screens (mobile phones)
  • sm = small screens (tablets)
  • md = medium screens (some desktops)
  • lg = large screens (remaining desktops)

Read the "Grid Options" chapter from the official Bootstrap documentation for more details.

You should usually classify a div using multiple column classes so it behaves differently depending on the screen size (this is the heart of what makes bootstrap responsive). eg: a div with classes col-xs-6 and col-sm-4 will span half the screen on the mobile phone (xs) and 1/3 of the screen on tablets(sm).

<div class="col-xs-6 col-sm-4">Column 1</div> <!-- 1/2 width on mobile, 1/3 screen on tablet) -->
<div class="col-xs-6 col-sm-8">Column 2</div> <!-- 1/2 width on mobile, 2/3 width on tablet -->

NOTE: as per comment below, grid classes for a given screen size apply to that screen size and larger unless another declaration overrides it (i.e. col-xs-6 col-md-4 spans 6 columns on xs and sm, and 4 columns on md and lg, even though sm and lg were never explicitly declared)

NOTE: if you don't define xs, it will default to col-xs-12 (i.e. col-sm-6 is half the width on sm, md and lg screens, but full-width on xs screens).

NOTE: it's actually totally fine if your .row includes more than 12 cols, as long as you are aware of how they will react. --This is a contentious issue, and not everyone agrees.

Create stacked barplot where each stack is scaled to sum to 100%

prop.table is a nice friendly way of obtaining proportions of tables.

m <- matrix(1:4,2)

     [,1] [,2]
[1,]    1    3
[2,]    2    4

Leaving margin blank gives you proportions of the whole table

 prop.table(m, margin=NULL)
     [,1] [,2]
[1,]  0.1  0.3
[2,]  0.2  0.4

Giving it 1 gives you row proportions

 prop.table(m, 1)
      [,1]      [,2]
[1,] 0.2500000 0.7500000
[2,] 0.3333333 0.6666667

And 2 is column proportions

 prop.table(m, 2)
          [,1]      [,2]
[1,] 0.3333333 0.4285714
[2,] 0.6666667 0.5714286

URL Encode a string in jQuery for an AJAX request

encodeURIComponent works fine for me. we can give the url like this in ajax call.The code shown below:

    cache: false,
    type: "POST",
    url: "",
    data: "strChannelName=" + $('#txtupdstorename').val() + "&ServiceUrl=" + encodeURIComponent($('#txtupdserviceurl').val()),
    dataType: "HTML",
    success: function (data) {
    error: function (xhr, ajaxOptions, thrownError) {

Ignore mapping one property with Automapper

Just for anyone trying to do this automatically, you can use that extension method to ignore non existing properties on the destination type :

public static IMappingExpression<TSource, TDestination> IgnoreAllNonExisting<TSource, TDestination>(this IMappingExpression<TSource, TDestination> expression)
    var sourceType = typeof(TSource);
    var destinationType = typeof(TDestination);
    var existingMaps = Mapper.GetAllTypeMaps().First(x => x.SourceType.Equals(sourceType)
        && x.DestinationType.Equals(destinationType));
    foreach (var property in existingMaps.GetUnmappedPropertyNames())
        expression.ForMember(property, opt => opt.Ignore());
    return expression;

to be used as follow :

Mapper.CreateMap<SourceType, DestinationType>().IgnoreAllNonExisting();

thanks to Can Gencer for the tip :)

source :

Index (zero based) must be greater than or equal to zero

String.Format must start with zero index "{0}" like this:

Aboutme.Text = String.Format("{0}", reader.GetString(0));

How do I select an element in jQuery by using a variable for the ID?

You can do it like this:

row_id = 5;
row = $("body").find('#'+row_id);

C# DropDownList with a Dictionary as DataSource

If the DropDownList is declared in your aspx page and not in the codebehind, you can do it like this.


<asp:DropDownList ID="ddlStatus" runat="server" DataSource="<%# Statuses %>"
     DataValueField="Key" DataTextField="Value"></asp:DropDownList>


protected void Page_Load(object sender, EventArgs e)
    // or use Page.DataBind() to bind everything

public Dictionary<int, string> Statuses
        // do database/webservice lookup here to populate Dictionary

Div 100% height works on Firefox but not in IE

I'm not sure what problem you are solving, but when I have two side by side containers that need to be the same height, I run a little javascript on page load that finds the maximum height of the two and explicitly sets the other to the same height. It seems to me that height: 100% might just mean "make it the size needed to fully contain the content" when what you really want is "make both the size of the largest content."

Note: you'll need to resize them again if anything happens on the page to change their height -- like a validation summary being made visible or a collapsible menu opening.

How can I return the difference between two lists?

With Stream API you can do something like this:

List<String> aWithoutB =
    .filter(element -> !b.contains(element))

List<String> bWithoutA =
    .filter(element -> !a.contains(element))

Javascript - How to show escape characters in a string?

If your goal is to have

str = "Hello\nWorld";

and output what it contains in string literal form, you can use JSON.stringify:

console.log(JSON.stringify(str)); // ""Hello\nWorld""

const str = "Hello\nWorld";_x000D_
const json = JSON.stringify(str);_x000D_
console.log(json); // ""Hello\nWorld""_x000D_
for (let i = 0; i < json.length; ++i) {_x000D_
    console.log(`${i}: ${json.charAt(i)}`);_x000D_
.as-console-wrapper {_x000D_
    max-height: 100% !important;_x000D_

console.log adds the outer quotes (at least in Chrome's implementation), but the content within them is a string literal (yes, that's somewhat confusing).

JSON.stringify takes what you give it (in this case, a string) and returns a string containing valid JSON for that value. So for the above, it returns an opening quote ("), the word Hello, a backslash (\), the letter n, the word World, and the closing quote ("). The linefeed in the string is escaped in the output as a \ and an n because that's how you encode a linefeed in JSON. Other escape sequences are similarly encoded.

How to set java_home on Windows 7?

What worked for me was adding the %JAVA_HOME%\bin to the Path environment variable with the JAVA_HOME environment variable pointing to the jdk folder.

JSON to pandas DataFrame

Optimization of the accepted answer:

The accepted answer has some functioning problems, so I want to share my code that does not rely on urllib2:

import requests
from pandas import json_normalize
url = ''

response = requests.get(url)
dictr = response.json()
recs = dictr['result']['records']
df = json_normalize(recs)


        _id                    HourUTC               HourDK  ... ElbasAveragePriceEUR  ElbasMaxPriceEUR  ElbasMinPriceEUR
0    264028  2019-01-01T00:00:00+00:00  2019-01-01T01:00:00  ...                  NaN               NaN               NaN
1    138428  2017-09-03T15:00:00+00:00  2017-09-03T17:00:00  ...                33.28              33.4              32.0
2    138429  2017-09-03T16:00:00+00:00  2017-09-03T18:00:00  ...                35.20              35.7              34.9
3    138430  2017-09-03T17:00:00+00:00  2017-09-03T19:00:00  ...                37.50              37.8              37.3
4    138431  2017-09-03T18:00:00+00:00  2017-09-03T20:00:00  ...                39.65              42.9              35.3
..      ...                        ...                  ...  ...                  ...               ...               ...
995  139290  2017-10-09T13:00:00+00:00  2017-10-09T15:00:00  ...                38.40              38.4              38.4
996  139291  2017-10-09T14:00:00+00:00  2017-10-09T16:00:00  ...                41.90              44.3              33.9
997  139292  2017-10-09T15:00:00+00:00  2017-10-09T17:00:00  ...                46.26              49.5              41.4
998  139293  2017-10-09T16:00:00+00:00  2017-10-09T18:00:00  ...                56.22              58.5              49.1
999  139294  2017-10-09T17:00:00+00:00  2017-10-09T19:00:00  ...                56.71              65.4              42.2 

PS: API is for Danish electricity prices

Batch files : How to leave the console window open

put at the end it will reopen your console

start cmd 

AssertionError: View function mapping is overwriting an existing endpoint function: main

This can happen also when you have identical function names on different routes.

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

You can compare by checksum algorithm like sha256

sha256sum oldFile > oldFile.sha256

echo "$(cat oldFile.sha256) newFile" | sha256sum --check

newFile: OK

if the files are distinct the result will be

newFile: FAILED
sha256sum: WARNING: 1 computed checksum did NOT match

How to make graphics with transparent background in R using ggplot2?

Updated with the theme() function, ggsave() and the code for the legend background:

df <- data.frame(y = d, x = 1, group = rep(c("gr1", "gr2"), 50))
p <- ggplot(df) +
  stat_boxplot(aes(x = x, y = y, color = group), 
               fill = "transparent" # for the inside of the boxplot

Fastest way is using using rect, as all the rectangle elements inherit from rect:

p <- p +
        rect = element_rect(fill = "transparent") # all rectangles

More controlled way is to use options of theme:

p <- p +
    panel.background = element_rect(fill = "transparent"), # bg of the panel
    plot.background = element_rect(fill = "transparent", color = NA), # bg of the plot
    panel.grid.major = element_blank(), # get rid of major grid
    panel.grid.minor = element_blank(), # get rid of minor grid
    legend.background = element_rect(fill = "transparent"), # get rid of legend bg = element_rect(fill = "transparent") # get rid of legend panel bg

To save (this last step is important):

ggsave(p, filename = "tr_tst2.png",  bg = "transparent")

How do I remove a CLOSE_WAIT socket connection

Even though too much of CLOSE_WAIT connections means there is something wrong with your code in the first and this is accepted not good practice.

You might want to check out:

What this script does is send out the ACK which the connection was waiting for.

This is what worked for me.

How do I dynamically set HTML5 data- attributes using react?

You should not wrap JavaScript expressions in quotes.

<option data-img-src={this.props.imageUrl} value="1">{this.props.title}</option>

Take a look at the JavaScript Expressions docs for more info.

Why is 22 the default port number for SFTP?

It's the default SSH port and SFTP is usually carried over an SSH tunnel.

Assign static IP to Docker container

Easy with Docker version 1.10.1, build 9e83765.

First you need to create your own docker network (mynet123)

docker network create --subnet= mynet123

then, simply run the image (I'll take ubuntu as example)

docker run --net mynet123 --ip -it ubuntu bash

then in ubuntu shell

ip addr

Additionally you could use

  • --hostname to specify a hostname
  • --add-host to add more entries to /etc/hosts

Docs (and why you need to create a network) at

sublime text2 python error message /usr/bin/python: can't find '__main__' module in ''

I got the same error as I didn't save the script before executing it. Check to see if you have saved it!

Reading text files using read.table

From ?read.table: The number of data columns is determined by looking at the first five lines of input (or the whole file if it has less than five lines), or from the length of col.names if it is specified and is longer. This could conceivably be wrong if fill or blank.lines.skip are true, so specify col.names if necessary.

So, perhaps your data file isn't clean. Being more specific will help the data import:

d = read.table("foobar.txt", 
               col.names=c("id", "name"), 

will specify exact columns and fill=FALSE will force a two column data frame.

Email address validation in C# MVC 4 application: with or without using Regex

It is surprising the question of validating an email address continually comes up on SO!

You can find one often-mentioned practical solution here: How to Find or Validate an Email Address.


The virtue of my regular expression above is that it matches 99% of the email addresses in use today. All the email address it matches can be handled by 99% of all email software out there. If you're looking for a quick solution, you only need to read the next paragraph. If you want to know all the trade-offs and get plenty of alternatives to choose from, read on.

See this answer on SO for a discussion of the merits of the article at the above link. In particular, the comment dated 2012-04-17 reads:

To all the complainers: after 3 hours experimenting all the solutions offered in this gigantic discussion, this is THE ONLY good java regex solution I can find. None of the rfc5322 stuff works on java regex.

How to configure custom PYTHONPATH with VM and PyCharm?

For PyCharm 5 (or 2016.1), you can:

  1. select Preferences > Project Interpreter
  2. to the right of interpreter selector there is a "..." button, click it
  3. select "more..."
  4. pop up a new "Project Interpreters" window
  5. select the rightest button (named "show paths for the selected interpreter")
  6. pop up a "Interpreter Paths" window
  7. click the "+" buttom > select your desired PYTHONPATH directory (the folder which contains python modules) and click OK
  8. Done! Enjoy it!

enter image description here

enter image description here

enter image description here enter image description here

Can I make 'git diff' only the line numbers AND changed file names?

Have you tried using :

git dif | grep -B <number of before lines to show> <regex>

In my case, i try to search where do i put a debug statement in the many files, i need to see which file already got this debug statement like this :

git diff | grep -B 5 dd\(

How to copy data from one HDFS to another HDFS?

DistCp (distributed copy) is a tool used for copying data between clusters. It uses MapReduce to effect its distribution, error handling and recovery, and reporting. It expands a list of files and directories into input to map tasks, each of which will copy a partition of the files specified in the source list.

Usage: $ hadoop distcp <src> <dst>

example: $ hadoop distcp hdfs://nn1:8020/file1 hdfs://nn2:8020/file2

file1 from nn1 is copied to nn2 with filename file2

Distcp is the best tool as of now. Sqoop is used to copy data from relational database to HDFS and vice versa, but not between HDFS to HDFS.

More info:

There are two versions available - runtime performance in distcp2 is more compared to distcp

Oracle to_date, from mm/dd/yyyy to dd-mm-yyyy

You don't need to muck about with extracting parts of the date. Just cast it to a date using to_date and the format in which its stored, then cast that date to a char in the format you want. Like this:

select to_char(to_date('1/10/2011','mm/dd/yyyy'),'mm-dd-yyyy') from dual

Play/pause HTML 5 video using JQuery

You can do


Check if element is visible in DOM

I've got a more performant solution compared to AlexZ's getComputedStyle() solution when one has position 'fixed' elements, if one is willing to ignore some edge cases (check comments):

function isVisible(el) {
    /* offsetParent would be null if display 'none' is set.
       However Chrome, IE and MS Edge returns offsetParent as null for elements
       with CSS position 'fixed'. So check whether the dimensions are zero.

       This check would be inaccurate if position is 'fixed' AND dimensions were
       intentionally set to zero. is good enough for most cases.*/
    if (!el.offsetParent && el.offsetWidth === 0 && el.offsetHeight === 0) {
        return false;
    return true;

Side note: Strictly speaking, "visibility" needs to be defined first. In my case, I am considering an element visible as long as I can run all DOM methods/properties on it without problems (even if opacity is 0 or CSS visibility property is 'hidden' etc).

How to Compare two strings using a if in a stored procedure in sql server 2008?

declare @temp as varchar
  set @temp='Measure'
  if(@temp = 'Measure')
Select Measure from Measuretable
Select OtherMeasure from Measuretable

How does MySQL CASE work?

I wanted a simple example of the use of case that I could play with, this doesn't even need a table. This returns odd or even depending whether seconds is odd or even


Fragment onResume() & onPause() is not called on backstack

  • Since you have used ft2.replace(), FragmentTransaction.remove() method is called and the Loginfragment will be removed. Refer to this. So onStop() of LoginFragment will be called instead of onPause(). (As the new fragment completely replaces the old one).
  • But since you have also used ft2.addtobackstack(), the state of the Loginfragment will be saved as a bundle and when you click back button from HomeFragment, onViewStateRestored() will be called followed by onStart() of LoginFragment. So eventually onResume() won't be called.

Validating input using java.util.Scanner

what i have tried is that first i took the integer input and checked that whether its is negative or not if its negative then again take the input

Scanner s=new Scanner(;

    int a=s.nextInt();
    System.out.println("please provide non negative integer input ");
    System.out.println("the non negative integer input is "+a);

Here, you need to take the character input first and check whether user gave character or not if not than again take the character input

    char ch = s.findInLine(".").charAt(0);
    System.out.println("please provide a character input ");
    System.out.println("the character  input is "+ch);

html5: display video inside canvas

You need to update currentTime video element and then draw the frame in canvas. Don't init play() event on the video.

You can also use for ex. this plugin

MySQLi prepared statements error reporting

Not sure if this answers your question or not. Sorry if not

To get the error reported from the mysql database about your query you need to use your connection object as the focus.


echo $mysqliDatabaseConnection->error

would echo the error being sent from mysql about your query.

Hope that helps

Using 'starts with' selector on individual class names

this is for prefix with


this is for starts with so you dont need to have the '-' char in there


you can find a bunch of other cool variations of the jQuery selector here

How to add MVC5 to Visual Studio 2013?

Go File -> New Project.

Select Web under Visual C#.

Select ASP.NET Web Application

Click OK.

New Project Dialog

Select MVC.

Click OK.

ASP.Net Dialog

Array of arrays (Python/NumPy)

It seems strange that you would write arrays without commas (is that a MATLAB syntax?)

Have you tried going through NumPy's documentation on multi-dimensional arrays?

It seems NumPy has a "Python-like" append method to add items to a NumPy n-dimensional array:

>>> p = np.array([[1,2],[3,4]])

>>> p = np.append(p, [[5,6]], 0)

>>> p = np.append(p, [[7],[8],[9]],1)

>>> p
array([[1, 2, 7], [3, 4, 8], [5, 6, 9]])

It has also been answered already...

From the documentation for MATLAB users:

You could use a matrix constructor which takes a string in the form of a matrix MATLAB literal:

mat("1 2 3; 4 5 6")


matrix("[1 2 3; 4 5 6]")

Please give it a try and tell me how it goes.

close fancy box from function from within open 'fancybox'

If you just want to close the fancy box it is sufficient to close it.


What is Common Gateway Interface (CGI)?

A CGI is a program (or a Web API) you write, and save it on the Web Server site. CGI is a file.

This file sits and waits on the Web Server. When the client browser sends a request to the Web Server to execute your CGI file, the Web Server runs your CGI file on the server site. The inputs for this CGI program, if any, are from the client browser. The outputs of this CGI program are sent to the browser.

What language you use to write a CGI program? Other posts already mention c,java, php, perl, etc.

Presenting modal in iOS 13 fullscreen

The above answers and suggestions are right, below is another version, and efficient way using programmatically.

#1 Created a UIView Extension

#2 Created a Method ()

extension UIViewController {

func presentLocal(_ viewControllerToPresent: UIViewController, animated flag: 
Bool, completion: (() -> Void)? = nil) {

//Reusing below 2 lines :-)
viewControllerToPresent.modalPresentationStyle = .overCurrentContext
self.present(viewControllerToPresent, animated: flag, completion: completion)


Invoking as below

let vc = MyViewController()
let nc = UINavigationController(rootViewController: vc)
sourceView.presentLocal(nc, animated: true, completion: nil)


let vc = MyViewController()
sourceView.presentLocal(vc, animated: true, completion: nil)

How to recover MySQL database from .myd, .myi, .frm files

I think .myi you can repair from inside mysql.

If you see these type of error messages from MySQL: Database failed to execute query (query) 1016: Can't open file: 'sometable.MYI'. (errno: 145) Error Msg: 1034: Incorrect key file for table: 'sometable'. Try to repair it thenb you probably have a crashed or corrupt table.

You can check and repair the table from a mysql prompt like this:

check table sometable;
| Table | Op | Msg_type | Msg_text | 
| yourdb.sometable | check | warning | Table is marked as crashed | 
| yourdb.sometable | check | status | OK | 

repair table sometable;
| Table | Op | Msg_type | Msg_text | 
| yourdb.sometable | repair | status | OK | 

and now your table should be fine:

check table sometable;
| Table | Op | Msg_type | Msg_text |
| yourdb.sometable | check | status | OK |

What JSON library to use in Scala?

@AlaxDean's #7 answer, Argonaut is the only one that I was able to get working quickly with sbt and intellij. Actually json4s also took little time but dealing with a raw AST is not what I wanted. I got argonaut to work by putting in a single line into my

libraryDependencies += "io.argonaut" %% "argonaut" % "6.0.1"

And then a simple test to see if it I could get JSON:

package mytest

import scalaz._, Scalaz._
import argonaut._, Argonaut._

object Mytest extends App {

  val requestJson  =
      "userid": "1"

  val updatedJson: Option[Json] = for {
    parsed <- requestJson.parseOption
  } yield ("name", jString("testuser")) ->: parsed

  val obj = updatedJson.get.obj
  printf("Updated user: %s\n", updatedJson.toString())
  printf("obj : %s\n", obj.toString())
  printf("userid: %s\n", obj.get.toMap("userid"))

And then

$ sbt
> run
Updated user: Some({"userid":"1","name":"testuser"})
obj : Some(object[("userid","1"),("name","testuser")])
userid: "1"

Make sure you are familiar with Option which is just a value that can also be null (null safe I guess). Argonaut makes use of Scalaz so if you see something you don't understand like the symbol \/ (an or operation) it's probably Scalaz.

Send request to curl with post data sourced from a file

I had to use a HTTP connection, because on HTTPS there is default file size limit.

    curl -i -X 'POST' -F 'file=@/home/testeincremental.xlsx' ''

Is there an equivalent of 'which' on the Windows command line?

Windows Server 2003 and later (i.e. anything after Windows XP 32 bit) provide the where.exe program which does some of what which does, though it matches all types of files, not just executable commands. (It does not match built-in shell commands like cd.) It will even accept wildcards, so where nt* finds all files in your %PATH% and current directory whose names start with nt.

Try where /? for help.

Note that Windows PowerShell defines where as an alias for the Where-Object cmdlet, so if you want where.exe, you need to type the full name instead of omitting the .exe extension.

best way to create object

There's not really a best way. Both are quite the same, unless you want to do some additional processing using the parameters passed to the constructor during initialization or if you want to ensure a coherent state just after calling the constructor. If it is the case, prefer the first one.

But for readability/maintainability reasons, avoid creating constructors with too many parameters.

In this case, both will do.

XSL substring and indexOf

I want to select the text of a string that is located after the occurrence of substring

You could use:


If you want a subtring of the above with some length then use:


But problems begin if there is no ocurrence of the matching substring... So, if you want a substring with specific length located after the occurrence of a substring, or from the whole string if there is no match, you could use:

          string-length($match) * contains($string,$match) + 1,

How can I update npm on Windows?

To install the updates, just download the installer from the site and run it again. The new version of Node.js and NPM will replace the older versions.

Loop through files in a folder using VBA?

The Dir function is the way to go, but the problem is that you cannot use the Dir function recursively, as stated here, towards the bottom.

The way that I've handled this is to use the Dir function to get all of the sub-folders for the target folder and load them into an array, then pass the array into a function that recurses.

Here's a class that I wrote that accomplishes this, it includes the ability to search for filters. (You'll have to forgive the Hungarian Notation, this was written when it was all the rage.)

Private m_asFilters() As String
Private m_asFiles As Variant
Private m_lNext As Long
Private m_lMax As Long

Public Function GetFileList(ByVal ParentDir As String, Optional ByVal sSearch As String, Optional ByVal Deep As Boolean = True) As Variant
    m_lNext = 0
    m_lMax = 0

    ReDim m_asFiles(0)
    If Len(sSearch) Then
        m_asFilters() = Split(sSearch, "|")
        ReDim m_asFilters(0)
    End If

    If Deep Then
        Call RecursiveAddFiles(ParentDir)
        Call AddFiles(ParentDir)
    End If

    If m_lNext Then
        ReDim Preserve m_asFiles(m_lNext - 1)
        GetFileList = m_asFiles
    End If

End Function

Private Sub RecursiveAddFiles(ByVal ParentDir As String)
    Dim asDirs() As String
    Dim l As Long
    On Error GoTo ErrRecursiveAddFiles
    'Add the files in 'this' directory!

    Call AddFiles(ParentDir)

    ReDim asDirs(-1 To -1)
    asDirs = GetDirList(ParentDir)
    For l = 0 To UBound(asDirs)
        Call RecursiveAddFiles(asDirs(l))
    Next l
    On Error GoTo 0
Exit Sub
End Sub
Private Function GetDirList(ByVal ParentDir As String) As String()
    Dim sDir As String
    Dim asRet() As String
    Dim l As Long
    Dim lMax As Long

    If Right(ParentDir, 1) <> "\" Then
        ParentDir = ParentDir & "\"
    End If
    sDir = Dir(ParentDir, vbDirectory Or vbHidden Or vbSystem)
    Do While Len(sDir)
        If GetAttr(ParentDir & sDir) And vbDirectory Then
            If Not (sDir = "." Or sDir = "..") Then
                If l >= lMax Then
                    lMax = lMax + 10
                    ReDim Preserve asRet(lMax)
                End If
                asRet(l) = ParentDir & sDir
                l = l + 1
            End If
        End If
        sDir = Dir
    If l Then
        ReDim Preserve asRet(l - 1)
        GetDirList = asRet()
    End If
End Function
Private Sub AddFiles(ByVal ParentDir As String)
    Dim sFile As String
    Dim l As Long

    If Right(ParentDir, 1) <> "\" Then
        ParentDir = ParentDir & "\"
    End If

    For l = 0 To UBound(m_asFilters)
        sFile = Dir(ParentDir & "\" & m_asFilters(l), vbArchive Or vbHidden Or vbNormal Or vbReadOnly Or vbSystem)
        Do While Len(sFile)
            If Not (sFile = "." Or sFile = "..") Then
                If m_lNext >= m_lMax Then
                    m_lMax = m_lMax + 100
                    ReDim Preserve m_asFiles(m_lMax)
                End If
                m_asFiles(m_lNext) = ParentDir & sFile
                m_lNext = m_lNext + 1
            End If
            sFile = Dir
    Next l
End Sub

How to reload .bash_profile from the command line?

. ~/.bash_profile

Just make sure you don't have any dependencies on the current state in there.

"The breakpoint will not currently be hit. The source code is different from the original version." What does this mean?

Did you ever do this?

Would you like to continue and run the last successful build?

If you ticked the box and pressed "Yes" you will get the last successful build running even though your project does not compile. This means that whenever you set a breakpoint, you will get that error.

Try changing this value:

  • Tools
    • Options
      • Projects and Solutions
        • Build and Run
          • On Run, when build or deployment errors occur: Do not Launch

Python - Locating the position of a regex match in a string?

I don't think this question has been completely answered yet because all of the answers only give single match examples. The OP's question demonstrates the nuances of having 2 matches as well as a substring match which should not be reported because it is not a word/token.

To match multiple occurrences, one might do something like this:

iter = re.finditer(r"\bis\b", String)
indices = [m.start(0) for m in iter]

This would return a list of the two indices for the original string.

How do I use the lines of a file as arguments of a command?

After editing @Wesley Rice's answer a couple times, I decided my changes were just getting too big to continue changing his answer instead of writing my own. So, I decided I need to write my own!

Read each line of a file in and operate on it line-by-line like this:

while IFS= read -r line
  echo "$line"
done < "$input"

This comes directly from author Vivek Gite here: He gets the credit!

Syntax: Read file line by line on a Bash Unix & Linux shell:
1. The syntax is as follows for bash, ksh, zsh, and all other shells to read a file line by line
2. while read -r line; do COMMAND; done < input.file
3. The -r option passed to read command prevents backslash escapes from being interpreted.
4. Add IFS= option before read command to prevent leading/trailing whitespace from being trimmed -
5. while IFS= read -r line; do COMMAND_on $line; done < input.file

And now to answer this now-closed question which I also had: Is it possible to `git add` a list of files from a file? - here's my answer:

Note that FILES_STAGED is a variable containing the absolute path to a file which contains a bunch of lines where each line is a relative path to a file I'd like to do git add on. This code snippet is about to become part of the "eRCaGuy_dotfiles/useful_scripts/" file in this project, to enable easy syncing of files in development from one PC (ex: a computer I code on) to another (ex: a more powerful computer I build on):

while IFS= read -r line
    echo "  git add \"$line\""
    git add "$line" 
done < "$FILES_STAGED"


  1. Where I copied my answer from:
  2. For loop syntax:


  1. How to read contents of file line-by-line and do git add on it: Is it possible to `git add` a list of files from a file?

Returning an empty array

You can return empty array by following two ways:

If you want to return array of int then

  1. Using {}:

    int arr[] = {};
    return arr;
  2. Using new int[0]:

    int arr[] = new int[0];
    return arr;

Same way you can return array for other datatypes as well.

Can I set max_retries for requests.request?

This will not only change the max_retries but also enable a backoff strategy which makes requests to all http:// addresses sleep for a period of time before retrying (to a total of 5 times):

import requests
from urllib3.util.retry import Retry
from requests.adapters import HTTPAdapter

s = requests.Session()

retries = Retry(total=5,
                status_forcelist=[ 500, 502, 503, 504 ])

s.mount('http://', HTTPAdapter(max_retries=retries))


As per documentation for Retry: if the backoff_factor is 0.1, then sleep() will sleep for [0.1s, 0.2s, 0.4s, ...] between retries. It will also force a retry if the status code returned is 500, 502, 503 or 504.

Various other options to Retry allow for more granular control:

  • total – Total number of retries to allow.
  • connect – How many connection-related errors to retry on.
  • read – How many times to retry on read errors.
  • redirect – How many redirects to perform.
  • method_whitelist – Set of uppercased HTTP method verbs that we should retry on.
  • status_forcelist – A set of HTTP status codes that we should force a retry on.
  • backoff_factor – A backoff factor to apply between attempts.
  • raise_on_redirect – Whether, if the number of redirects is exhausted, to raise a MaxRetryError, or to return a response with a response code in the 3xx range.
  • raise_on_status – Similar meaning to raise_on_redirect: whether we should raise an exception, or return a response, if status falls in status_forcelist range and retries have been exhausted.

NB: raise_on_status is relatively new, and has not made it into a release of urllib3 or requests yet. The raise_on_status keyword argument appears to have made it into the standard library at most in python version 3.6.

To make requests retry on specific HTTP status codes, use status_forcelist. For example, status_forcelist=[503] will retry on status code 503 (service unavailable).

By default, the retry only fires for these conditions:

  • Could not get a connection from the pool.
  • TimeoutError
  • HTTPException raised (from http.client in Python 3 else httplib). This seems to be low-level HTTP exceptions, like URL or protocol not formed correctly.
  • SocketError
  • ProtocolError

Notice that these are all exceptions that prevent a regular HTTP response from being received. If any regular response is generated, no retry is done. Without using the status_forcelist, even a response with status 500 will not be retried.

To make it behave in a manner which is more intuitive for working with a remote API or web server, I would use the above code snippet, which forces retries on statuses 500, 502, 503 and 504, all of which are not uncommon on the web and (possibly) recoverable given a big enough backoff period.

EDITED: Import Retry class directly from urllib3.

Hiding and Showing TabPages in tabControl

I've been using the same approach of saving the hidden TabPages in a private list, but the problem is that when I want to show the TabPage again, they doesn't appears in the original position (order). So, finally, I wrote a class in VB to add the TabControl with two methods: HideTabPageByName and ShowTabPageByName. You can just call the methods passing the name (not the TabPage instance).

Public Class CS_Control_TabControl
    Inherits System.Windows.Forms.TabControl

    Private mTabPagesHidden As New Dictionary(Of String, System.Windows.Forms.TabPage)
    Private mTabPagesOrder As List(Of String)

    Public Sub HideTabPageByName(ByVal TabPageName As String)
        If mTabPagesOrder Is Nothing Then
            ' The first time the Hide method is called, save the original order of the TabPages
            mTabPagesOrder = New List(Of String)
            For Each TabPageCurrent As TabPage In Me.TabPages
        End If

        If Me.TabPages.ContainsKey(TabPageName) Then
            Dim TabPageToHide As TabPage

            ' Get the TabPage object
            TabPageToHide = TabPages(TabPageName)
            ' Add the TabPage to the internal List
            mTabPagesHidden.Add(TabPageName, TabPageToHide)
            ' Remove the TabPage from the TabPages collection of the TabControl
        End If
    End Sub

    Public Sub ShowTabPageByName(ByVal TabPageName As String)
        If mTabPagesHidden.ContainsKey(TabPageName) Then
            Dim TabPageToShow As TabPage

            ' Get the TabPage object
            TabPageToShow = mTabPagesHidden(TabPageName)
            ' Add the TabPage to the TabPages collection of the TabControl
            Me.TabPages.Insert(GetTabPageInsertionPoint(TabPageName), TabPageToShow)
            ' Remove the TabPage from the internal List
        End If
    End Sub

    Private Function GetTabPageInsertionPoint(ByVal TabPageName As String) As Integer
        Dim TabPageIndex As Integer
        Dim TabPageCurrent As TabPage
        Dim TabNameIndex As Integer
        Dim TabNameCurrent As String

        For TabPageIndex = 0 To Me.TabPages.Count - 1
            TabPageCurrent = Me.TabPages(TabPageIndex)
            For TabNameIndex = TabPageIndex To mTabPagesOrder.Count - 1
                TabNameCurrent = mTabPagesOrder(TabNameIndex)
                If TabNameCurrent = TabPageCurrent.Name Then
                    Exit For
                End If
                If TabNameCurrent = TabPageName Then
                    Return TabPageIndex
                End If
        Return TabPageIndex
    End Function

    Protected Overrides Sub Finalize()
        mTabPagesHidden = Nothing
        mTabPagesOrder = Nothing
    End Sub
End Class

What is a database transaction?

I think a transaction is an atomic action in terms of DBMS.

that means it cannot be seperated. yes, in a transction, there may be several instructions for the system to execute. but they are binded together to finished a single basic task.

for example. you need to walk through a bridge (let's treat this as a transction), and to do this, say, you need 100 steps. overall, these steps cannot be seperated. when you've done half of them, there is only two choice for you: continue to finish them all, and go back to the start point. it's just like the to result of a transaction: success( committed ) and fail( rollback )

How do I set the eclipse.ini -vm option?

I am not sure if something has changed, but I just tried the other answers regarding entries in "eclipse.ini" for Eclipse Galileo SR2 (Windows XP SR3) and none worked. Java is jdk1.6.0_18 and is the default Windows install. Things improved when I dropped "\javaw.exe" from the path.

Also, I can't thank enough the mention that -vm needs to be first line in the ini file. I believe that really helped me out.

Thus my eclipse.ini file starts with:

C:\Program Files\Java\jdk1.6.0_18\bin

FYI, my particular need to specify launching Eclipse with a JDK arose from my wanting to work with the m2eclipse plugin.

how to make negative numbers into positive

abs() is for integers only. For floating point, use fabs() (or one of the fabs() line with the correct precision for whatever a actually is)

Python: fastest way to create a list of n lists

Here are two methods, one sweet and simple(and conceptual), the other more formal and can be extended in a variety of situations, after having read a dataset.

Method 1: Conceptual

X2 thus has [[1,2,3],[4,5,6]] ie a list of lists. 

Method 2 : Formal and extensible

Another elegant way to store a list as a list of lists of different numbers - which it reads from a file. (The file here has the dataset train) Train is a data-set with say 50 rows and 20 columns. ie. Train[0] gives me the 1st row of a csv file, train[1] gives me the 2nd row and so on. I am interested in separating the dataset with 50 rows as one list, except the column 0 , which is my explained variable here, so must be removed from the orignal train dataset, and then scaling up list after list- ie a list of a list. Here's the code that does that.

Note that I am reading from "1" in the inner loop since I am interested in explanatory variables only. And I re-initialize X1=[] in the other loop, else the X2.append([0:(len(train[0])-1)]) will rewrite X1 over and over again - besides it more memory efficient.

for j in range(0,len(train)):
    for k in range(1,len(train[0])):

How do I get the name of the current executable in C#?

Super easy, here:

Environment.CurrentDirectory + "\\" + Process.GetCurrentProcess().ProcessName

Python Matplotlib Y-Axis ticks on Right Side of Plot

Use ax.yaxis.tick_right()

for example:

from matplotlib import pyplot as plt

f = plt.figure()
ax = f.add_subplot(111)

enter image description here

How to calculate the difference between two dates using PHP?

$date = '2012.11.13';
$dateOfReturn = '2017.10.31';

$substract = str_replace('.', '-', $date);

$substract2 = str_replace('.', '-', $dateOfReturn);

$date1 = $substract;
$date2 = $substract2;

$ts1 = strtotime($date1);
$ts2 = strtotime($date2);

$year1 = date('Y', $ts1);
$year2 = date('Y', $ts2);

$month1 = date('m', $ts1);
$month2 = date('m', $ts2);

echo $diff = (($year2 - $year1) * 12) + ($month2 - $month1);

How to set an image as a background for Frame in Swing GUI of java?

Here is another quick approach without using additional panel.

JFrame f = new JFrame("stackoverflow") { 
  private Image backgroundImage = File("background.jpg"));
  public void paint( Graphics g ) { 
    g.drawImage(backgroundImage, 0, 0, null);

Unable to resolve host "<URL here>" No address associated with host name

I've seen this problem in the emulator as well. In my case, it is caused by launching the emulator, then putting the computer to sleep or changing the network connection (going from work to home, etc), then attempting to use the same emulator again. Closing and re-launching the emulator resolves the problem in this case.

Bulk insert with SQLAlchemy ORM

The best answer I found so far was in sqlalchemy documentation:

There is a complete example of a benchmark of possible solutions.

As shown in the documentation:

bulk_save_objects is not the best solution but it performance are correct.

The second best implementation in terms of readability I think was with the SQLAlchemy Core:

def test_sqlalchemy_core(n=100000):
    t0 = time.time()
            [{"name": 'NAME ' + str(i)} for i in xrange(n)]

The context of this function is given in the documentation article.

Is null reference possible?


#include <iostream>
#include <functional>

struct null_ref_t {
   template <typename T>
   operator T&() {
      union TypeSafetyBreaker {
         T *ptr;

         // see
         std::reference_wrapper<T> ref; 

      TypeSafetyBreaker ptr = {.ptr = nullptr};

      // unwrap the reference
      return ptr.ref.get();

null_ref_t nullref;

int main() {
   int &a = nullref;

   // Segmentation fault
   a = 4;
   return 0;

What is the difference between signed and unsigned int

In practice, there are two differences:

  1. printing (eg with cout in C++ or printf in C): unsigned integer bit representation is interpreted as a nonnegative integer by print functions.
  2. ordering: the ordering depends on signed or unsigned specifications.

this code can identify the integer using ordering criterion:

char a = 0;
if (0 < a)

char is considered signed in some compilers and unsigned in other compilers. The code above determines which one is considered in a compiler, using the ordering criterion. If a is unsigned, after a--, it will be greater than 0, but if it is signed it will be less than zero. But in both cases, the bit representation of a is the same. That is, in both cases a-- does the same change to the bit representation.

How to set the LDFLAGS in CMakeLists.txt?

For linking against libraries see Andre's answer.

For linker flags - the following 4 CMake variables:


can be easily manipulated for different configs (debug, release...) with the ucm_add_linker_flags macro of ucm

How do I add a placeholder on a CharField in Django?

It's undesirable to have to know how to instantiate a widget when you just want to override its placeholder.

    q = forms.CharField(label='search')
    q.widget.attrs['placeholder'] = "Search"

Visual Studio debugging/loading very slow

Another last resort solution with respect to time is to repair the VS installation.

  • Go to Tools => Get Tools and Features
  • Locate the existing VS installation, and choose repair under the more button.
    • For example: Visual Studio Enterprise 2019 installation.

How to fix Cannot find module 'typescript' in Angular 4?

If you don't have particular needs, I suggest to install Typescript locally.

NPM Installation Method

npm install --global typescript # Global installation
npm install --save-dev typescript # Local installation

Yarn Installation Method

yarn global add typescript # Global installation
yarn add --dev typescript # Local installation

How can I solve "Either the parameter @objname is ambiguous or the claimed @objtype (COLUMN) is wrong."?

This works

EXEC sp_rename 
@objname = 'ENG_TEst."[ENG_Test_A/C_TYPE]"', 
@newname = 'ENG_Test_A/C_TYPE', 
@objtype = 'COLUMN'

Android: How do I prevent the soft keyboard from pushing my view up?

This one worked for me


How to rollback everything to previous commit

If you have pushed the commits upstream...

Select the commit you would like to roll back to and reverse the changes by clicking Reverse File, Reverse Hunk or Reverse Selected Lines. Do this for all the commits after the commit you would like to roll back to also.

reverse stuff reverse commit

If you have not pushed the commits upstream...

Right click on the commit and click on Reset current branch to this commit.

reset branch to commit

Commenting multiple lines in DOS batch file

try this:

   @echo off 2>Nul 3>Nul 4>Nul

   ben ali
   gadeffi ?

   echo hello Tunisia


How to detect the character encoding of a text file?

I use Ude that is a C# port of Mozilla Universal Charset Detector. It is easy to use and gives some really good results.

Read a variable in bash with a default value


read -p "Please enter IN_PATH [$IN_PATH_DEFAULT]: " IN_PATH

read -p "Please enter OUT_PATH [$OUT_PATH_DEFAULT]: " OUT_PATH

echo "Input: $IN_PATH Output: $OUT_PATH"

Sample run:

Please enter IN_PATH [/tmp/input.txt]: 
Please enter OUT_PATH [/tmp/output.txt]: ~/out.txt
Input: /tmp/input.txt Output: ~/out.txt

DateTime to javascript date

If you use MVC with razor


var dt1 = DateTime.Now.AddDays(14).Date;
    var dt2 = DateTime.Now.AddDays(18).Date;

    var lstDateTime = new List<DateTime>();


$(function() {

            var arr = []; //javascript array

            @foreach (var item in lstDateTime)
                @:arr1.push(new Date(@item.Year, @(item.Month - 1), @item.Day));
  • 1: create the list in C# and fill it
  • 2: Create an array in javascript
  • 3: Use razor to iterate the list
  • 4: Use @: to switch back to js and @ to switch to C#
  • 5: The -1 in the month to correct the month number in js.

Good luck

Use of True, False, and None as return values in Python functions

You can directly check that a variable contains a value or not, like if var or not var.

How to get the response of XMLHttpRequest?

I'd suggest looking into fetch. It is the ES5 equivalent and uses Promises. It is much more readable and easily customizable.

const url = "";
        response => response.text() // .json(), etc.
        // same as function(response) {return response.text();}
        html => console.log(html)

In Node.js, you'll need to import fetch using:

const fetch = require("node-fetch");

If you want to use it synchronously (doesn't work in top scope):

const json = await fetch(url)
  .then(response => response.json())
  .catch((e) => {});

More Info:

Mozilla Documentation

Can I Use (95% Feb 2020)

Matt Walsh Tutorial

Maximum number of records in a MySQL database table

Row Size Limits

The maximum row size for a given table is determined by several factors:
  • The internal representation of a MySQL table has a maximum row size limit of 65,535 bytes, even if the storage engine is capable of supporting larger rows. BLOB and TEXT columns only contribute 9 to 12 bytes toward the row size limit because their contents are stored separately from the rest of the row.

  • The maximum row size for an InnoDB table, which applies to data stored locally within a database page, is slightly less than half a page. For example, the maximum row size is slightly less than 8KB for the default 16KB InnoDB page size, which is defined by the innodb_page_size configuration option. “Limits on InnoDB Tables”.

  • If a row containing variable-length columns exceeds the InnoDB maximum row size, InnoDB selects variable-length columns for external off-page storage until the row fits within the InnoDB row size limit. The amount of data stored locally for variable-length columns that are stored off-page differs by row format. For more information, see “InnoDB Row Storage and Row Formats”.
  • Different storage formats use different amounts of page header and trailer data, which affects the amount of storage available for rows.

Which method performs better: .Any() vs .Count() > 0?

You can make a simple test to figure this out:

var query = //make any query here
var timeCount = new Stopwatch();
if (query.Count > 0)
var testCount = timeCount.Elapsed;

var timeAny = new Stopwatch();
if (query.Any())
var testAny = timeAny.Elapsed;

Check the values of testCount and testAny.

What are the differences between "git commit" and "git push"?

Basically git commit "records changes to the repository" while git push "updates remote refs along with associated objects". So the first one is used in connection with your local repository, while the latter one is used to interact with a remote repository.

Here is a nice picture from Oliver Steele, that explains the git model and the commands:

Git data transport commands

Read more about git push and git pull on (the article I referred to first)

Insecure content in iframe on secure page

Based on generality of this question, I think, that you'll need to setup your own HTTPS proxy on some server online. Do the following steps:

  • Prepare your proxy server - install IIS, Apache
  • Get valid SSL certificate to avoid security errors (free from for example)
  • Write a wrapper, which will download insecure content (how to below)
  • From your site/app get

If you simply download remote site content via file_get_contents or similiar, you can still have insecure links to content. You'll have to find them with regex and also replace. Images are hard to solve, but Ï found workaround here:

Note: While this solution may have worked in some browsers when it was written in 2014, it no longer works. Navigating or redirecting to an HTTP URL in an iframe embedded in an HTTPS page is not permitted by modern browsers, even if the frame started out with an HTTPS URL.

The best solution I created is to simply use google as the ssl proxy...

Tested and works in firefox.

Other Methods:

  • Use a Third party such as (but it it really only good for well known http APIs).

  • Create your own redirect script on an https page you control (a simple javascript redirect on a relative linked page should do the trick. Something like: (you can use any langauge/method) That has a iframe linking to... Which has a simple js redirect script like...

    document.location.href ="";

  • Alternatively, you could add an RSS feed or write some reader/parser to read the http site and display it within your https site.

  • You could/should also recommend to the http site owner that they create an ssl connection. If for no other reason than it increases seo.

Unless you can get the http site owner to create an ssl certificate, the most secure and permanent solution would be to create an RSS feed grabing the content you need (presumably you are not actually 'doing' anything on the http site -that is to say not logging in to any system).

The real issue is that having http elements inside a https site represents a security issue. There are no completely kosher ways around this security risk so the above are just current work arounds.

Note, that you can disable this security measure in most browsers (yourself, not for others). Also note that these 'hacks' may become obsolete over time.

Cmake doesn't find Boost

For cmake version 3.1.0-rc2 to pick up boost 1.57 specify -D_boost_TEST_VERSIONS=1.57

cmake version 3.1.0-rc2 defaults to boost<=1.56.0 as is seen using -DBoost_DEBUG=ON


Edit seaborn legend

If legend_out is set to True then legend is available thought g._legend property and it is a part of a figure. Seaborn legend is standard matplotlib legend object. Therefore you may change legend texts like:

import seaborn as sns

tips = sns.load_dataset("tips")
g = sns.lmplot(x="total_bill", y="tip", hue="smoker",
 data=tips, markers=["o", "x"], legend_out = True)

# title
new_title = 'My title'
# replace labels
new_labels = ['label 1', 'label 2']
for t, l in zip(g._legend.texts, new_labels): t.set_text(l)

enter image description here

Another situation if legend_out is set to False. You have to define which axes has a legend (in below example this is axis number 0):

import seaborn as sns

tips = sns.load_dataset("tips")
g = sns.lmplot(x="total_bill", y="tip", hue="smoker",
 data=tips, markers=["o", "x"], legend_out = False)

# check axes and find which is have legend
leg = g.axes.flat[0].get_legend()
new_title = 'My title'
new_labels = ['label 1', 'label 2']
for t, l in zip(leg.texts, new_labels): t.set_text(l)

enter image description here

Moreover you may combine both situations and use this code:

import seaborn as sns

tips = sns.load_dataset("tips")
g = sns.lmplot(x="total_bill", y="tip", hue="smoker",
 data=tips, markers=["o", "x"], legend_out = True)

# check axes and find which is have legend
for ax in g.axes.flat:
    leg = g.axes.flat[0].get_legend()
    if not leg is None: break
# or legend may be on a figure
if leg is None: leg = g._legend

# change legend texts
new_title = 'My title'
new_labels = ['label 1', 'label 2']
for t, l in zip(leg.texts, new_labels): t.set_text(l)

This code works for any seaborn plot which is based on Grid class.

How can I convert a Timestamp into either Date or DateTime object?

You can also get DateTime object from timestamp, including your current daylight saving time:

public DateTime getDateTimeFromTimestamp(Long value) {
    TimeZone timeZone = TimeZone.getDefault();
    long offset = timeZone.getOffset(value);
    if (offset < 0) {
        value -= offset;
    } else {
        value += offset;
    return new DateTime(value);

How to use IntelliJ IDEA to find all unused code?

Just use Analyze | Inspect Code with appropriate inspection enabled (Unused declaration under Declaration redundancy group).

Using IntelliJ 11 CE you can now "Analyze | Run Inspection by Name ... | Unused declaration"

get name of a variable or parameter

Pre C# 6.0 solution

You can use this to get a name of any provided member:

public static class MemberInfoGetting
    public static string GetMemberName<T>(Expression<Func<T>> memberExpression)
        MemberExpression expressionBody = (MemberExpression)memberExpression.Body;
        return expressionBody.Member.Name;

To get name of a variable:

string testVariable = "value";
string nameOfTestVariable = MemberInfoGetting.GetMemberName(() => testVariable);

To get name of a parameter:

public class TestClass
    public void TestMethod(string param1, string param2)
        string nameOfParam1 = MemberInfoGetting.GetMemberName(() => param1);

C# 6.0 and higher solution

You can use the nameof operator for parameters, variables and properties alike:

string testVariable = "value";
string nameOfTestVariable = nameof(testVariable);

When to use SELECT ... FOR UPDATE?

Short answers:

Q1: Yes.

Q2: Doesn't matter which you use.

Long answer:

A select ... for update will (as it implies) select certain rows but also lock them as if they have already been updated by the current transaction (or as if the identity update had been performed). This allows you to update them again in the current transaction and then commit, without another transaction being able to modify these rows in any way.

Another way of looking at it, it is as if the following two statements are executed atomically:

select * from my_table where my_condition;

update my_table set my_column = my_column where my_condition;

Since the rows affected by my_condition are locked, no other transaction can modify them in any way, and hence, transaction isolation level makes no difference here.

Note also that transaction isolation level is independent of locking: setting a different isolation level doesn't allow you to get around locking and update rows in a different transaction that are locked by your transaction.

What transaction isolation levels do guarantee (at different levels) is the consistency of data while transactions are in progress.

How to capture the screenshot of a specific element rather than entire page using Selenium Webdriver?

This is my version, in C#, I was basically get most part from Brook's answer and modified it to fit my purpose

public static byte[] GetElementImage(this IWebElement element)
        var screenShot = MobileDriver.Driver.GetScreenshot();
        using (var stream = new MemoryStream(screenShot.AsByteArray))
            var screenBitmap = new Bitmap(stream);
            var elementBitmap = screenBitmap.Clone(
                new Rectangle(
            var converter = new ImageConverter();
            return (byte[]) converter.ConvertTo(elementBitmap, typeof(byte[]));

SQL Server Restore Error - Access is Denied

From the error message, it says there's an error when validating the target (c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DataLabTables.mdf) of your restore operation.

That sounds like:

a) that file already exists (because you've already restored it previously) and is in use by SQL Server


b) that directory doesn't exist at all

In your question, you mentioned you created a backup for that table - that's not how SQL Server backups work. Those backups are always the whole database (or at least one or several filegroups from that database).

My hunch is: you've already restored that database previously, and now, upon a second restore, you didn't check the checkbox "Overwrite existing database" in your restore wizard - thus the existing file cannot be overwritten and the restore fails.

The user that's running the restore on your remote server obviously doesn't have access to that directory on the remote server.

C:\program files\.... is a protected directory - normal (non-admin) users don't have access to this directory (and its subdirectories).

Easiest solution: try putting your BAK file somewhere else (e.g. C:\temp) and restore it from there

Read Excel File in Python

This is one approach:

from xlrd import open_workbook

class Arm(object):
    def __init__(self, id, dsp_name, dsp_code, hub_code, pin_code, pptl): = id
        self.dsp_name = dsp_name
        self.dsp_code = dsp_code
        self.hub_code = hub_code
        self.pin_code = pin_code
        self.pptl = pptl

    def __str__(self):
        return("Arm object:\n"
               "  Arm_id = {0}\n"
               "  DSPName = {1}\n"
               "  DSPCode = {2}\n"
               "  HubCode = {3}\n"
               "  PinCode = {4} \n"
               "  PPTL = {5}"
               .format(, self.dsp_name, self.dsp_code,
                       self.hub_code, self.pin_code, self.pptl))

wb = open_workbook('sample.xls')
for sheet in wb.sheets():
    number_of_rows = sheet.nrows
    number_of_columns = sheet.ncols

    items = []

    rows = []
    for row in range(1, number_of_rows):
        values = []
        for col in range(number_of_columns):
            value  = (sheet.cell(row,col).value)
                value = str(int(value))
            except ValueError:
        item = Arm(*values)

for item in items:
    print item
    print("Accessing one single value (eg. DSPName): {0}".format(item.dsp_name))

You don't have to use a custom class, you can simply take a dict(). If you use a class however, you can access all values via dot-notation, as you see above.

Here is the output of the script above:

Arm object:
  Arm_id = 1
  DSPName = JaVAS
  DSPCode = 1
  HubCode = AGR
  PinCode = 282001 
  PPTL = 1
Accessing one single value (eg. DSPName): JaVAS

Arm object:
  Arm_id = 2
  DSPName = JaVAS
  DSPCode = 1
  HubCode = AGR
  PinCode = 282002 
  PPTL = 3
Accessing one single value (eg. DSPName): JaVAS

Arm object:
  Arm_id = 3
  DSPName = JaVAS
  DSPCode = 1
  HubCode = AGR
  PinCode = 282003 
  PPTL = 5
Accessing one single value (eg. DSPName): JaVAS

How to reverse a singly linked list using only two pointers?

#include <stdio.h>
#include <malloc.h>

tydef struct node
    int info;
    struct node *link;
} *start;

void main()

void rev()
    struct node *p = start, *q = NULL, *r;
    while (p != NULL)
        r = q;
        q = p;
        p = p->link;
        q->link = r;

    start = q;

Launch an app from within another (iPhone)

No it's not. Besides the documented URL handlers, there's no way to communicate with/launch another app.

Laravel 5 - artisan seed [ReflectionException] Class SongsTableSeeder does not exist

If you migrated to Laravel 8, you have to add a namespace to the seeders class:


namespace Database\Seeders;


Next, in your composer.json file, remove classmap block from the autoload section and add the new namespaced class directory mappings:

"autoload": {
    "psr-4": {
        "App\\": "app/",
        "Database\\Seeders\\": "database/seeds/"

An finally, do a composer dump-autoload.

For more information:

Why does cURL return error "(23) Failed writing body"?

You can do this instead of using -o option:

curl [url] > [file]

How to wait in a batch script?

What about:

@echo off
set wait=%1
echo waiting %wait% s
echo wscript.sleep %wait%000 > wait.vbs
wscript.exe wait.vbs
del wait.vbs

How to disable XDebug

For WAMP, click left click on the Wamp icon in the taskbar tray. Hover over PHP and then click on php.ini and open it in your texteditor.

Now, search for the phrase 'zend_extension' and add ; (semicolon) in front it.

Restart the WAMP and you are good to go.

Oracle SQL: Use sequence in insert with Select Statement

I tested and the script run ok!

    WHERE YEAR = '2010' AND MONTH = '12'

you can read this article to understand more!

Remove leading or trailing spaces in an entire column of data

If you would like to use a formula, the TRIM function will do exactly what you're looking for:

|    |     A      |           B         |
| 1  | =TRIM(B1)  |  value to trim here |

So to do the whole column...
1) Insert a column
2) Insert TRIM function pointed at cell you are trying to correct.
3) Copy formula down the page
4) Copy inserted column
5) Paste as "Values"

Should be good to go from there...

Convert .pem to .crt and .key

Converting Using OpenSSL

These commands allow you to convert certificates and keys to different formats to make them compatible with specific types of servers or software.

  • Convert a DER file (.crt .cer .der) to PEM

    openssl x509 -inform der -in certificate.cer -out certificate.pem
  • Convert a PEM file to DER

    openssl x509 -outform der -in certificate.pem -out certificate.der
  • Convert a PKCS#12 file (.pfx .p12) containing a private key and certificates to PEM

    openssl pkcs12 -in keyStore.pfx -out keyStore.pem -nodes
    You can add -nocerts to only output the private key or add -nokeys to only output the certificates.
  • Convert a PEM certificate file and a private key to PKCS#12 (.pfx .p12)

    openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt -certfile CACert.crt
  • Convert PEM to CRT (.CRT file)

    openssl x509 -outform der -in certificate.pem -out certificate.crt

OpenSSL Convert PEM

  • Convert PEM to DER

    openssl x509 -outform der -in certificate.pem -out certificate.der
  • Convert PEM to P7B

    openssl crl2pkcs7 -nocrl -certfile certificate.cer -out certificate.p7b -certfile CACert.cer
  • Convert PEM to PFX

    openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt -certfile CACert.crt

OpenSSL Convert DER

  • Convert DER to PEM

    openssl x509 -inform der -in certificate.cer -out certificate.pem

OpenSSL Convert P7B

  • Convert P7B to PEM

    openssl pkcs7 -print_certs -in certificate.p7b -out certificate.cer
  • Convert P7B to PFX

    openssl pkcs7 -print_certs -in certificate.p7b -out certificate.cer
    openssl pkcs12 -export -in certificate.cer -inkey privateKey.key -out certificate.pfx -certfile CACert.cer

OpenSSL Convert PFX

  • Convert PFX to PEM

    openssl pkcs12 -in certificate.pfx -out certificate.cer -nodes

Generate rsa keys by OpenSSL

  • Using OpenSSL on the command line you’d first need to generate a public and private key, you should password protect this file using the -passout argument, there are many different forms that this argument can take so consult the OpenSSL documentation about that.

    openssl genrsa -out private.pem 1024
  • This creates a key file called private.pem that uses 1024 bits. This file actually have both the private and public keys, so you should extract the public one from this file:

    openssl rsa -in private.pem -out public.pem -outform PEM -pubout
    openssl rsa -in private.pem -pubout > public.pem
    openssl rsa -in private.pem -pubout -out public.pem

    You’ll now have public.pem containing just your public key, you can freely share this with 3rd parties. You can test it all by just encrypting something yourself using your public key and then decrypting using your private key, first we need a bit of data to encrypt:

  • Example file :

    echo 'too many secrets' > file.txt
  • You now have some data in file.txt, lets encrypt it using OpenSSL and the public key:

    openssl rsautl -encrypt -inkey public.pem -pubin -in file.txt -out file.ssl
  • This creates an encrypted version of file.txt calling it file.ssl, if you look at this file it’s just binary junk, nothing very useful to anyone. Now you can unencrypt it using the private key:

    openssl rsautl -decrypt -inkey private.pem -in file.ssl -out decrypted.txt
  • You will now have an unencrypted file in decrypted.txt:

    cat decrypted.txt
    |output -> too many secrets

RSA TOOLS Options in OpenSSL

  • NAME

    rsa - RSA key processing tool


    openssl rsa [-help] [-inform PEM|NET|DER] [-outform PEM|NET|DER] [-in filename] [-passin arg] [-out filename] [-passout arg] [-aes128] [-aes192] [-aes256] [-camellia128] [-camellia192] [-camellia256] [-des] [-des3] [-idea] [-text] [-noout] [-modulus] [-check] [-pubin] [-pubout] [-RSAPublicKey_in] [-RSAPublicKey_out] [-engine id]


    The rsa command processes RSA keys. They can be converted between various forms and their components printed out. Note this command uses the traditional SSLeay compatible format for private key encryption: newer applications should use the more secure PKCS#8 format using the pkcs8 utility.



    Print out a usage message.

    -inform DER|NET|PEM

    This specifies the input format. The DER option uses an ASN1 DER encoded form compatible with the PKCS#1 RSAPrivateKey or SubjectPublicKeyInfo format. The PEM form is the default format: it consists of the DER format base64 encoded with additional header and footer lines. On input PKCS#8 format private keys are also accepted. The NET form is a format is described in the NOTES section.

    -outform DER|NET|PEM

    This specifies the output format, the options have the same meaning as the -inform option.

    -in filename

    This specifies the input filename to read a key from or standard input if this option is not specified. If the key is encrypted a pass phrase will be prompted for.

    -passin arg

    the input file password source. For more information about the format of arg see the PASS PHRASE ARGUMENTS section in openssl.

    -out filename

    This specifies the output filename to write a key to or standard output if this option is not specified. If any encryption options are set then a pass phrase will be prompted for. The output filename should not be the same as the input filename.

    -passout password

    the output file password source. For more information about the format of arg see the PASS PHRASE ARGUMENTS section in openssl.


    These options encrypt the private key with the specified cipher before outputting it. A pass phrase is prompted for. If none of these options is specified the key is written in plain text. This means that using the rsa utility to read in an encrypted key with no encryption option can be used to remove the pass phrase from a key, or by setting the encryption options it can be use to add or change the pass phrase. These options can only be used with PEM format output files.


    prints out the various public or private key components in plain text in addition to the encoded version.


    this option prevents output of the encoded version of the key.


    this option prints out the value of the modulus of the key.


    this option checks the consistency of an RSA private key.


    by default a private key is read from the input file: with this option a public key is read instead.


    by default a private key is output: with this option a public key will be output instead. This option is automatically set if the input is a public key.

    -RSAPublicKey_in, -RSAPublicKey_out

    like -pubin and -pubout except RSAPublicKey format is used instead.

    -engine id

    specifying an engine (by its unique id string) will cause rsa to attempt to obtain a functional reference to the specified engine, thus initialising it if needed. The engine will then be set as the default for all available algorithms.


    The PEM private key format uses the header and footer lines:

    -----END RSA PRIVATE KEY-----

    The PEM public key format uses the header and footer lines:

    -----BEGIN PUBLIC KEY-----
    -----END PUBLIC KEY-----

    The PEM RSAPublicKey format uses the header and footer lines:

    -----BEGIN RSA PUBLIC KEY-----
    -----END RSA PUBLIC KEY-----

    The NET form is a format compatible with older Netscape servers and Microsoft IIS .key files, this uses unsalted RC4 for its encryption. It is not very secure and so should only be used when necessary.

    Some newer version of IIS have additional data in the exported .key files. To use these with the utility, view the file with a binary editor and look for the string "private-key", then trace back to the byte sequence 0x30, 0x82 (this is an ASN1 SEQUENCE). Copy all the data from this point onwards to another file and use that as the input to the rsa utility with the -inform NET option.


    To remove the pass phrase on an RSA private key:

     openssl rsa -in key.pem -out keyout.pem

    To encrypt a private key using triple DES:

     openssl rsa -in key.pem -des3 -out keyout.pem

    To convert a private key from PEM to DER format:

      openssl rsa -in key.pem -outform DER -out keyout.der

    To print out the components of a private key to standard output:

      openssl rsa -in key.pem -text -noout

    To just output the public part of a private key:

      openssl rsa -in key.pem -pubout -out pubkey.pem

    Output the public part of a private key in RSAPublicKey format:

      openssl rsa -in key.pem -RSAPublicKey_out -out pubkey.pem

How can I render Partial views in mvc 3?

<%= Html.Partial("PartialName", Model) %>

MySQL select one column DISTINCT, with corresponding other columns

SELECT DISTINCT(firstName), ID, LastName from tableName GROUP BY firstName

Would be the best bet IMO

Can someone explain how to append an element to an array in C programming?

You can have a counter (freePosition), which will track the next free place in an array of size n.

Can I pass a JavaScript variable to another browser window?

The function will also allow this if you have a reference to the window created, provided it is on the same domain. If the variable is used server side you should be using a $_SESSION variable (assuming you are using PHP).

Text in Border CSS HTML

You can do something like this, where you set a negative margin on the h1 (or whatever header you are using)

    border:2px solid black;


Note: you need to set a background as well as a width on the h1



To make it work with hiding the div, you could use some jQuery like this

    var a = $('h1').detach();

(You will need to modify...)

Example #2:

Random numbers with Math.random() in Java

Your formula generates numbers between min and min + max.

The one Google found generates numbers between min and max.

Google wins!

Ctrl+click doesn't work in Eclipse Juno

The solution for me was to configure the build path to include the project itself.

  1. Right click on open project.
  2. highlight build path
  3. click on Configure build path…
  4. click on Source
  5. Click Add Folder… button.
  6. Put a check mark next to your project.
  7. Click OK.

If necessary, click the project menu and choose the ‘clean…’ option to rebuild.

max(length(field)) in mysql

Use CHAR_LENGTH() instead-of LENGTH() as suggested in: MySQL - length() vs char_length()

SELECT name, CHAR_LENGTH(name) AS mlen FROM mytable ORDER BY mlen DESC LIMIT 1

How can I make this try_files directive work?

a very common try_files line which can be applied on your condition is

location / {
    try_files $uri $uri/ /test/index.html;

you probably understand the first part, location / matches all locations, unless it's matched by a more specific location, like location /test for example

The second part ( the try_files ) means when you receive a URI that's matched by this block try $uri first, for example nginx will try to check if there's a file inside /images called image.jpg if found it will serve it first.

Second condition is $uri/ which means if you didn't find the first condition $uri try the URI as a directory, for example, ngixn will first check if a file called images exists then it wont find it, then goes to second check $uri/ and see if there's a directory called images exists then it will try serving it.

Side note: if you don't have autoindex on you'll probably get a 403 forbidden error, because directory listing is forbidden by default.

EDIT: I forgot to mention that if you have index defined, nginx will try to check if the index exists inside this folder before trying directory listing.

Third condition /test/index.html is considered a fall back option, (you need to use at least 2 options, one and a fall back), you can use as much as you can (never read of a constriction before), nginx will look for the file index.html inside the folder test and serve it if it exists.

If the third condition fails too, then nginx will serve the 404 error page.

Also there's something called named locations, like this

location @error {

You can call it with try_files like this

try_files $uri $uri/ @error;

TIP: If you only have 1 condition you want to serve, like for example inside folder images you only want to either serve the image or go to 404 error, you can write a line like this

location /images {
    try_files $uri =404;

which means either serve the file or serve a 404 error, you can't use only $uri by it self without =404 because you need to have a fallback option.
You can also choose which ever error code you want, like for example:

location /images {
    try_files $uri =403;

This will show a forbidden error if the image doesn't exist, or if you use 500 it will show server error, etc ..

The application was unable to start correctly (0xc000007b)

I experienced the same problem developing a client-server app using Microsoft Visual Studio 2012.

If you used Visual Studio to develop the app, you must make sure the new (i.e. the computer that the software was not developed on) has the appropriate Microsoft Visual C++ Redistributable Package. By appropriate, you need the right year and bit version (i.e. x86 for 32 bit and x64 for 64 bit) of the Visual C++ Redistributable Package.

The Visual C++ Redistributable Packages install run-time components that are required to run C++ applications built using Visual Studio.

Here is a link to the Visual C++ Redistributable for Visual Studio 2015 .

You can check what versions are installed by going to Control Panel -> Programs -> Programs and Features.

Here's how I got this error and fixed it:

1) I developed a 32 bit application using Visual Studio 2012 on my computer. Let's call my computer ComputerA.

2) I installed the .exe and the related files on a different computer we'll call ComputerB.

3) On ComputerB, I ran the .exe and got the error message.

4) On ComputerB, I looked at the Programs and Features and didn't see Visual C++ 2012 Redistributable (x64).

5) On ComputerB, I googled for Visual C++ 2012 Redistributable and selected and installed the x64 version.

6) On ComputerB, I ran the .exe on ComputerB and did not receive the error message.

Execution failed for task ':app:compileDebugAidl': aidl is missing

To build your application without aidl is missing error with compileSdkVersion 23 and buildToolsVersion "23.0.1" you should specify latest versions for Android Gradle plugin (and Google Play Services Gradle plugin if you are using it) in main build.gradle file:

buildscript {
    repositories {
    dependencies {
        classpath ''
        classpath ''

Test file upload using HTTP PUT method

If you're using PHP you can test your PUT upload using the code below:

#Initiate cURL object
$curl = curl_init();
#Set your URL
curl_setopt($curl, CURLOPT_URL, '');
#Indicate, that you plan to upload a file
curl_setopt($curl, CURLOPT_UPLOAD, true);
#Indicate your protocol
#Set flags for transfer
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_BINARYTRANSFER, 1);
#Disable header (optional)
curl_setopt($curl, CURLOPT_HEADER, false);
#Set HTTP method to PUT
curl_setopt($curl, CURLOPT_PUT, 1);
#Indicate the file you want to upload
curl_setopt($curl, CURLOPT_INFILE, fopen('path_to_file', 'rb'));
#Indicate the size of the file (it does not look like this is mandatory, though)
curl_setopt($curl, CURLOPT_INFILESIZE, filesize('path_to_file'));
#Only use below option on TEST environment if you have a self-signed certificate!!! On production this can cause security issues
#curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);

Upgrading Node.js to latest version

brew upgrade node

will upgrade to the latest version of the node

count of entries in data frame in R

using sqldf fits here:

sqldf("SELECT Believe, Count(1) as N FROM Santa
       GROUP BY Believe")

Creating a Plot Window of a Particular Size

This will depend on the device you're using. If you're using a pdf device, you can do this:

pdf( "mygraph.pdf", width = 11, height = 8 )
plot( x, y )

You can then divide up the space in the pdf using the mfrow parameter like this:

par( mfrow = c(2,2) )

That makes a pdf with four panels available for plotting. Unfortunately, some of the devices take different units than others. For example, I think that X11 uses pixels, while I'm certain that pdf uses inches. If you'd just like to create several devices and plot different things to them, you can use, dev.list(), and

Other devices that might be useful include:

There's a list of all of the devices here.

How do I resolve "HTTP Error 500.19 - Internal Server Error" on IIS7.0

For others out there, I got a similar error message due to trying to run a .Net 4 app in a .Net 2 app pool. Changing the .Net FX version for the app pool fixed it for me.

Blue and Purple Default links, how to remove?

REMOVE DEFAULT LINK SOLVED that :visited thing is css.... you just go to your HTML and add a simple

< a href="" style="text-decoration: none" > < /a>

... thats the way html pages used to be

ProcessBuilder: Forwarding stdout and stderr of started processes without blocking the main thread

A flexible solution with Java 8 lambda that lets you provide a Consumer that will process the output (eg. log it) line by line. run() is a one-liner with no checked exceptions thrown. Alternatively to implementing Runnable, it can extend Thread instead as other answers suggest.

class StreamGobbler implements Runnable {
    private InputStream inputStream;
    private Consumer<String> consumeInputLine;

    public StreamGobbler(InputStream inputStream, Consumer<String> consumeInputLine) {
        this.inputStream = inputStream;
        this.consumeInputLine = consumeInputLine;

    public void run() {
        new BufferedReader(new InputStreamReader(inputStream)).lines().forEach(consumeInputLine);

You can then use it for example like this:

public void runProcessWithGobblers() throws IOException, InterruptedException {
    Process p = new ProcessBuilder("...").start();
    Logger logger = LoggerFactory.getLogger(getClass());

    StreamGobbler outputGobbler = new StreamGobbler(p.getInputStream(), System.out::println);
    StreamGobbler errorGobbler = new StreamGobbler(p.getErrorStream(), logger::error);

    new Thread(outputGobbler).start();
    new Thread(errorGobbler).start();

Here the output stream is redirected to System.out and the error stream is logged on the error level by the logger.

Deserialize a JSON array in C#

public string name { get; set; }
public int required { get; set; }
public string type { get; set; }

and Remove a "{"..,

strFieldString = strFieldString.Remove(0, strFieldString.IndexOf('{'));


   optionsItem objActualField = JsonConvert.DeserializeObject<optionsItem(strFieldString);

std::unique_lock<std::mutex> or std::lock_guard<std::mutex>?

There are certain common things between lock_guard and unique_lock and certain differences.

But in the context of the question asked, the compiler does not allow using a lock_guard in combination with a condition variable, because when a thread calls wait on a condition variable, the mutex gets unlocked automatically and when other thread/threads notify and the current thread is invoked (comes out of wait), the lock is re-acquired.

This phenomenon is against the principle of lock_guard. lock_guard can be constructed only once and destructed only once.

Hence lock_guard cannot be used in combination with a condition variable, but a unique_lock can be (because unique_lock can be locked and unlocked several times).

iOS 8 Snapshotting a view that has not been rendered results in an empty snapshot

I have came across with this issue. When we call the camera and release the views produced this issue. For an example call an camera and set view nil in viewDidDisappear method this error will come since there is not callback for camera event. Make sure about this case too for this error.

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'

working example:

Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/your_db_name?autoReconnect=true&useSSL=false", "root", "root");

call like this it will work.

Easiest way to develop simple GUI in Python

Take your pick here.

Tkinter is in the Python stdlib.

Hosting ASP.NET in IIS7 gives Access is denied?

I went round and round on this and it turned out to be improperly set default page. Hope this helps someone else avoid an hour of wasted time.

Jenkins Git Plugin: How to build specific tag?

I was able to do that by using the "branches to build" parameter:

Branch Specifier (blank for default): tags/[tag-name]

Replace [tag-name] by the name of your tag.

How can one use multi threading in PHP applications

Depending on what you're trying to do you could also use curl_multi to achieve it.

How do I resolve "Cannot find module" error using Node.js?

Check if the enviroment variable NODE_PATH is set correctly and pointing to the node_modules path. nodejs uses this variable to search for the libraries

Run script with rc.local: script works, but not at boot

This is most probably caused by a missing or incomplete PATH environment variable.

If you provide full absolute paths to your executables (su and node) it will work.

Oracle: how to INSERT if a row doesn't exist

You should use Merge: For example:

MERGE INTO employees e
    USING (SELECT * FROM hr_records WHERE start_date > ADD_MONTHS(SYSDATE, -1)) h
    ON ( = h.emp_id)
    UPDATE SET e.address = h.address
    INSERT (id, address)
    VALUES (h.emp_id, h.address);


MERGE INTO employees e
    USING hr_records h
    ON ( = h.emp_id)
    UPDATE SET e.address = h.address
    INSERT (id, address)
    VALUES (h.emp_id, h.address);

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

WARNING: Not for git newbies.

This comes up enough in my workflow that I've almost tried to write a new git command for it. The usual git stash flow is the way to go but is a little awkward. I usually make a new commit first since if I have been looking at the changes, all the information is fresh in my mind and it's better to just start git commit-ing what I found (usually a bugfix belonging on master that I discover while working on a feature branch) right away.

It is also helpful—if you run into situations like this a lot—to have another working directory alongside your current one that always have the master branch checked out.

So how I achieve this goes like this:

  1. git commit the changes right away with a good commit message.
  2. git reset HEAD~1 to undo the commit from current branch.
  3. (optional) continue working on the feature.

Sometimes later (asynchronously), or immediately in another terminal window:

  1. cd my-project-master which is another WD sharing the same .git
  2. git reflog to find the bugfix I've just made.
  3. git cherry-pick SHA1 of the commit.

Optionally (still asynchronous) you can then rebase (or merge) your feature branch to get the bugfix, usually when you are about to submit a PR and have cleaned your feature branch and WD already:

  1. cd my-project which is the main WD I'm working on.
  2. git rebase master to get the bugfixes.

This way I can keep working on the feature uninterrupted and not have to worry about git stash-ing anything or having to clean my WD before a git checkout (and then having the check the feature branch backout again.) and still have all my bugfixes goes to master instead of hidden in my feature branch.

IMO git stash and git checkout is a real PIA when you are in the middle of working on some big feature.

C Macro definition to determine big endian or little endian machine?

Try this:

int x=1;
#define TEST (*(char*)&(x)==1)?printf("little endian"):printf("Big endian")
int main()


Do I need to pass the full path of a file in another directory to open()?

The examples to os.walk in the documentation show how to do this:

for root, dirs, filenames in os.walk(indir):
    for f in filenames:
        log = open(os.path.join(root, f),'r')

How did you expect the "open" function to know that the string "1" is supposed to mean "/home/des/test/1" (unless "/home/des/test" happens to be your current working directory)?

Postgres - Transpose Rows to Columns

If anyone else that finds this question and needs a dynamic solution for this where you have an undefined number of columns to transpose to and not exactly 3, you can find a nice solution here:

If the different dependencies have a same jar also cause this build error.

For example:


If "library1" and "library2" has a same jar named xxx.jar, this will make such an error.

Twitter API returns error 215, Bad Authentication Data

The url with /1.1/ in it is correct, it is the new Twitter API Version 1.1.

But you need an application and authorize your application (and the user) using oAuth.

Read more about this on the Twitter Developers documentation site :)

Single Result from Database by using mySQLi

If you assume just one result you could do this as in Edwin suggested by using specific users id.

$someUserId = 'abc123';

$stmt = $mysqli->prepare("SELECT ssfullname, ssemail FROM userss WHERE user_id = ?");
$stmt->bind_param('s', $someUserId);


$stmt->bind_result($ssfullname, $ssemail);

ChromePhp::log($ssfullname, $ssemail); //log result in chrome if ChromePhp is used.

OR as "Your Common Sense" which selects just one user.

$stmt = $mysqli->prepare("SELECT ssfullname, ssemail FROM userss ORDER BY ssid LIMIT 1");

$stmt->bind_result($ssfullname, $ssemail);

Nothing really different from the above except for PHP v.5

disable horizontal scroll on mobile web

I've found this answer over here on stackoverflow which works perfectly for me:

use this in style

body {
    overflow-x: hidden;
    width: 100%;

Use this in head tag

<meta name="viewport" content="user-scalable=no, width=device-width, initial-scale=1.0" />
<meta name="apple-mobile-web-app-capable" content="yes" />

A slight addition of mine in case your body has padding (to prevent the device from scaling to the body content-box, and thus still adding a horizontal scrollbar):

body {
    overflow-x: hidden;
    width: 100%;
    -webkit-box-sizing: border-box;
       -moz-box-sizing: border-box;
            box-sizing: border-box;

Calling virtual functions inside constructors

One solution to your problem is using factory methods to create your object.

  • Define a common base class for your class hierarchy containing a virtual method afterConstruction():
class Object
  virtual void afterConstruction() {}
  // ...
  • Define a factory method:
template< class C >
C* factoryNew()
  C* pObject = new C();

  return pObject;
  • Use it like this:
class MyClass : public Object 
  virtual void afterConstruction()
    // do something.
  // ...

MyClass* pMyObject = factoryNew();

How to check if bootstrap modal is open, so I can use jquery validate?

On bootstrap-modal.js v2.2.0:

( $('element').data('modal') || {}).isShown

How to call javascript function from code-behind

This is a way to invoke one or more JavaScript methods from the code behind. By using Script Manager we can call the methods in sequence. Consider the below code for example.

ScriptManager.RegisterStartupScript(this, typeof(Page), "UpdateMsg", 
    alert('Overrides successfully Updated.');

In this first method EnableControls() is invoked. Next the alert will be displayed. Next the DisableControls() method will be invoked.

How to programmatically open the Permission Screen for a specific app on Android Marshmallow?

Kotlin style.

    startActivity(Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS).apply {
        data = Uri.fromParts("package", packageName, null)

Setting Windows PATH for Postgres tools

configuring postreSQL PATH variable on Windows 7

I encountered this issue too. I'm using Git Bash, hence the Unix-style $ prompt on Windows.

$ rails db
Couldn't find database client: psql, psql.exe.  Check your $PATH and try again.

Here's what I did:

In Windows 7, navigate to:

Control Panel
  All Control Panel Items
      Advanced System Settings
        Environment Variables
          from the System Variables box select "PATH"

Then append this string to the existing PATH Variable Value:

;C:\Program Files\PostgreSQL\9.2\bin

and click "OK" three times to exit the menus.

Now, close the console and restart it.

Navigate back to the directory of your Rails app. In my case, this is accomplished with:

$ cd rails_projects/sample_app

Then, try again:

$ rails db


How do I put PostgreSQL /bin directory on my path in Windows?

Cause of a process being a deadlock victim

Here is how this particular deadlock problem actually occurred and how it was actually resolved. This is a fairly active database with 130K transactions occurring daily. The indexes in the tables in this database were originally clustered. The client requested us to make the indexes nonclustered. As soon as we did, the deadlocking began. When we reestablished the indexes as clustered, the deadlocking stopped.

CSS way to horizontally align table

This should work:

<div style="text-align:center;">
  <table style="margin: 0 auto;">
    <!-- table markup here. -->

How to find keys of a hash?

you can use Object.keys


element not interactable exception in selenium web automation

I had the same problem and then figured out the cause. I was trying to type in a span tag instead of an input tag. My XPath was written with a span tag, which was a wrong thing to do. I reviewed the Html for the element and found the problem. All I then did was to find the input tag which happens to be a child element. You can only type in an input field if your XPath is created with an input tagname