Programs & Examples On #Bevelled

How to create a WPF Window without a border that can be resized via a grip only?

If you set the AllowsTransparency property on the Window (even without setting any transparency values) the border disappears and you can only resize via the grip.

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Width="640" Height="480" 
    WindowStyle="None"
    AllowsTransparency="True"
    ResizeMode="CanResizeWithGrip">

    <!-- Content -->

</Window>

Result looks like:

CronJob not running

To add another point, a file in /etc/cron.d must contain an empty new line at the end. This is likely related to the response by Luciano which specifies that:

The entire command portion of the line, up to a newline or a "%"
character, will be executed

How to find a Java Memory Leak

There are tools that should help you find your leak, like JProbe, YourKit, AD4J or JRockit Mission Control. The last is the one that I personally know best. Any good tool should let you drill down to a level where you can easily identify what leaks, and where the leaking objects are allocated.

Using HashTables, Hashmaps or similar is one of the few ways that you can acually leak memory in Java at all. If I had to find the leak by hand I would peridically print the size of my HashMaps, and from there find the one where I add items and forget to delete them.

How do I limit the number of results returned from grep?

Awk approach:

awk '/pattern/{print; count++; if (count==10) exit}' file

How to serve static files in Flask

A simplest working example based on the other answers is the following:

from flask import Flask, request
app = Flask(__name__, static_url_path='')

@app.route('/index/')
def root():
    return app.send_static_file('index.html')

if __name__ == '__main__':
  app.run(debug=True)

With the HTML called index.html:

<!DOCTYPE html>
<html>
<head>
    <title>Hello World!</title>
</head>
<body>
    <div>
         <p>
            This is a test.
         </p>
    </div>
</body>
</html>

IMPORTANT: And index.html is in a folder called static, meaning <projectpath> has the .py file, and <projectpath>\static has the html file.

If you want the server to be visible on the network, use app.run(debug=True, host='0.0.0.0')

EDIT: For showing all files in the folder if requested, use this

@app.route('/<path:path>')
def static_file(path):
    return app.send_static_file(path)

Which is essentially BlackMamba's answer, so give them an upvote.

How to list processes attached to a shared memory segment in linux?

Just in case someone is interest only in what kind of process created the shared moeries, call

ls -l /dev/shm

It lists the names that are associated with the shared memories - at least on Ubuntu. Usually the names are quite telling.

Unable to create a constant value of type Only primitive types or enumeration types are supported in this context

It's worth adding, since the OP's code sample doesn't provide enough context to prove otherwise, but I received this error as well on the following code:

public RetailSale GetByRefersToRetailSaleId(Int32 refersToRetailSaleId)
{
    return GetQueryable()
        .FirstOrDefault(x => x.RefersToRetailSaleId.Equals(refersToRetailSaleId));
}

Apparently, I cannot use Int32.Equals in this context to compare an Int32 with a primitive int; I had to (safely) change to this:

public RetailSale GetByRefersToRetailSaleId(Int32 refersToRetailSaleId)
{
    return GetQueryable()
      .FirstOrDefault(x => x.RefersToRetailSaleId == refersToRetailSaleId);
}

Using Tkinter in python to edit the title bar

For anybody who runs into the issue of having two windows open, and runs across this question. Here is how I stumbled upon a solution.

The reason the code in this question is producing two windows is because

Frame.__init__(self, parent)

is being run before

self.root = Tk()

The simple fix is to run Tk() before running Frame.__init_()

self.root = Tk()
Frame.__init__(self, parent)

Why that is the case, I'm not entirely sure.

Change MySQL default character set to UTF-8 in my.cnf?

To set the default to UTF-8, you want to add the following to my.cnf/my.ini

[client]
default-character-set=utf8mb4

[mysql]
default-character-set=utf8mb4


[mysqld]
collation-server = utf8mb4_unicode_520_ci
init-connect='SET NAMES utf8mb4'
character-set-server = utf8mb4

If you want to change the character set for an existing DB, let me know... your question didn't specify it directly so I am not sure if that's what you want to do.

Edit: I replaced utf8 with utf8mb4 in the original answer due to utf8 only being a subset of UTF-8. MySQL and MariaDB both call UTF-8 utf8mb4.

span with onclick event inside a tag

Fnd the answer.

I have use some styles inorder to achive this.

<span 
   class="pseudolink" 
   onclick="location='https://jsfiddle.net/'">
Go TO URL
</span>

.pseudolink { 
   color:blue; 
   text-decoration:underline; 
   cursor:pointer; 
   }

https://jsfiddle.net/mafais/bys46d5w/

SELECTING with multiple WHERE conditions on same column

Try to use this alternate query:

SELECT A.CONTACTID 
FROM (SELECT CONTACTID FROM TESTTBL WHERE FLAG = 'VOLUNTEER')A , 
(SELECT CONTACTID FROM TESTTBL WHERE FLAG = 'UPLOADED') B WHERE A.CONTACTID = B.CONTACTID;

How to increase Neo4j's maximum file open limit (ulimit) in Ubuntu?

What you are doing will not work for root user. Maybe you are running your services as root and hence you don't get to see the change.

To increase the ulimit for root user you should replace the * by root. * does not apply for root user. Rest is the same as you did. I will re-quote it here.

Add the following lines to the file: /etc/security/limits.conf

root soft  nofile 40000

root hard  nofile 40000

And then add following line in the file: /etc/pam.d/common-session

session required pam_limits.so

This will update the ulimit for root user. As mentioned in comments, you may don't even have to reboot to see the change.

Remove the last three characters from a string

read last 3 characters from string [Initially asked question]

You can use string.Substring and give it the starting index and it will get the substring starting from given index till end.

myString.Substring(myString.Length-3)

Retrieves a substring from this instance. The substring starts at a specified character position. MSDN

Edit, for updated post

Remove last 3 characters from string [Updated question]

To remove the last three characters from the string you can use string.Substring(Int32, Int32) and give it the starting index 0 and end index three less than the string length. It will get the substring before last three characters.

myString = myString.Substring(0, myString.Length-3);

String.Substring Method (Int32, Int32)

Retrieves a substring from this instance. The substring starts at a specified character position and has a specified length.

You can also using String.Remove(Int32) method to remove the last three characters by passing start index as length - 3, it will remove from this point to end of string.

myString = myString.Remove(myString.Length-3)

String.Remove Method (Int32)

Returns a new string in which all the characters in the current instance, beginning at a specified position and continuing through the last position, have been deleted

Python: how to print range a-z?

This is your 2nd question: string.lowercase[ord('a')-97:ord('n')-97:2] because 97==ord('a') -- if you want to learn a bit you should figure out the rest yourself ;-)

Convert a String to int?

So basically you want to convert a String into an Integer right! here is what I mostly use and that is also mentioned in official documentation..

fn main() {

    let char = "23";
    let char : i32 = char.trim().parse().unwrap();
    println!("{}", char + 1);

}

This works for both String and &str Hope this will help too.

Why do I keep getting 'SVN: Working Copy XXXX locked; try performing 'cleanup'?

Make sure you exactly cleanup what the console says. For example if a subfolder (a package) is locked:

   svn: E155004: Commit failed (details follow):
  svn: E155004: Working copy 'C:\Users\laura\workspace\tparser\src\de\test\order' locked
  svn: E155004: 'C:\Users\laura\workspace\tparser\src\de\test\order' is already locked.

cleanup C:/Users/liparulol/workspace/tparser/src/de/mc/etn/parsers/order

Then you need to cleanup the specified folder and not the whole project. If you are in eclipse right click on the package, not on the project folder and execute the clean up.

PHP Fatal error: Call to undefined function mssql_connect()

php.ini probably needs to read: extension=ext\php_sqlsrv_53_nts.dll

Or move the file to same directory as the php executable. This is what I did to my php5 install this week to get odbc_pdo working. :P

Additionally, that doesn't look like proper phpinfo() output. If you make a file with contents
<? phpinfo(); ?> and visit that page, the HTML output should show several sections, including one with loaded modules. (Edited to add: like shown in the screenshot of the above accepted answer)

use Lodash to sort array of object by value

This method orderBy does not change the input array, you have to assign the result to your array :

var chars = this.state.characters;

chars = _.orderBy(chars, ['name'],['asc']); // Use Lodash to sort array by 'name'

 this.setState({characters: chars})

How do I use SELECT GROUP BY in DataTable.Select(Expression)?

This solution sort by Col1 and group by Col2. Then extract value of Col2 and display it in a mbox.

var grouped = from DataRow dr in dt.Rows orderby dr["Col1"] group dr by dr["Col2"];
string x = "";
foreach (var k in grouped) x += (string)(k.ElementAt(0)["Col2"]) + Environment.NewLine;
MessageBox.Show(x);

How can I select all elements without a given class in jQuery?

You can use the .not() method or :not() selector

Code based on your example:

$("ul#list li").not(".active") // not method
$("ul#list li:not(.active)")   // not selector

How to enable Bootstrap tooltip on disabled button?

If it helps anyone, I was able to get a disabled button to show a tooltip by simply putting a span inside it and applying the tooltip stuff there, angularjs around it...

<button ng-click="$ctrl.onClickDoThis()"
        ng-disabled="!$ctrl.selectedStuff.length">
  <span tooltip-enable="!$ctrl.selectedStuff.length"
        tooltip-append-to-body="true"
        uib-tooltip="Select at least one thing to enable button.">
    My Butt
  </span>
</button>

Evaluate expression given as a string

Nowadays you can also use lazy_eval function from lazyeval package.

> lazyeval::lazy_eval("5+5")
[1] 10

Iterator invalidation rules

Here is a nice summary table from cppreference.com:

enter image description here

Here, insertion refers to any method which adds one or more elements to the container and erasure refers to any method which removes one or more elements from the container.

How do I connect to a MySQL Database in Python?

Even though some of you may mark this as a duplicate and get upset that I am copying someone else's answer, I would REALLY like to highlight an aspect of Mr. Napik's response. Because I missed this, I caused nationwide website downtime (9min). If only someone shared this information, I could have prevented it!

Here is his code:

import mysql.connector    
cnx = mysql.connector.connect(user='scott', password='tiger',
                              host='127.0.0.1',
                              database='employees')
try:
   cursor = cnx.cursor()
   cursor.execute("""select 3 from your_table""")
   result = cursor.fetchall()
   print(result)
finally:
    cnx.close()

The important thing here is the Try and Finally clause. This allows connections to ALWAYS be closed, regardless of what happens in the cursor/sqlstatement portion of the code. A lot of active connections cause DBLoadNoCPU to spike and could crash a db server.

I hope this warning helps to save servers and ultimately jobs! :D

Converting JSON String to Dictionary Not List

You can use the following:

import json

 with open('<yourFile>.json', 'r') as JSON:
       json_dict = json.load(JSON)

 # Now you can use it like dictionary
 # For example:

 print(json_dict["username"])

VBA vlookup reference in different sheet

It's been many functions, macros and objects since I posted this question. The way I handled it, which is mentioned in one of the answers here, is by creating a string function that handles the errors that get generate by the vlookup function, and returns either nothing or the vlookup result if any.

Function fsVlookup(ByVal pSearch As Range, ByVal pMatrix As Range, ByVal pMatColNum As Integer) As String
    Dim s As String
    On Error Resume Next
    s = Application.WorksheetFunction.VLookup(pSearch, pMatrix, pMatColNum, False)
    If IsError(s) Then
        fsVlookup = ""
    Else
        fsVlookup = s
    End If
End Function

One could argue about the position of the error handling or by shortening this code, but it works in all cases for me, and as they say, "if it ain't broke, don't try and fix it".

Eliminate extra separators below UITableView

I just add this line at the ViewDidLoad function and problem fixed.

tableView.tableFooterView = [[UIView alloc] init]; 

How to install a PHP IDE plugin for Eclipse directly from the Eclipse environment?

The new URL for the repository is now http://download.eclipse.org/tools/pdt/updates/release. In Eclipse: open Help -> install new sofware -> add. Then paste this URL in the location.

Mark the check boxes you want and click next.

Invalid application path

I was also getting this error, I found that it was because I had deleted the Default Application Pool "DefaultAppPool". Re-creating it fixed the problem. Drove me crazy for a few days.

This error will appear if either the web application is mapped to a non-existent app-pool; or if that application pool is stopped.

How to get Bitmap from an Uri?

Use startActivityForResult metod like below

        startActivityForResult(new Intent(Intent.ACTION_PICK).setType("image/*"), PICK_IMAGE);

And you can get result like this:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode != RESULT_OK) {
        return;
    }
    switch (requestCode) {
        case PICK_IMAGE:
            Uri imageUri = data.getData();
            try {
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imageUri);
            } catch (IOException e) {
                e.printStackTrace();
            }
         break;
    }
}

jQuery autoComplete view all on click?

You can trigger this event to show all of the options:

$("#example").autocomplete( "search", "" );

Or see the example in the link below. Looks like exactly what you want to do.

http://jqueryui.com/demos/autocomplete/#combobox

EDIT (from @cnanney)

Note: You must set minLength: 0 in your autocomplete for an empty search string to return all elements.

how to run the command mvn eclipse:eclipse

Right click on the project

->Run As --> Run configurations.

Then select Maven Build

Then click new button to create a configuration of the selected type. Click on Browse workspace (now is Workspace...) then select your project and in goals specify eclipse:eclipse

How to link to specific line number on github

@broc.seib has a sophisticated answer, I just want to point out that instead of pressing y to get the permanent link, github now has a very simple UI that helps you to achieve it

  1. Select line by clicking on the line number or select multiple lines by downholding shift(same as how you select multiple folders in file explorer) enter image description here

  2. on the right hand corner of the first line you selected, expand ... and click copy permalink enter image description here

  3. that's it, a link with selected lines and commit hash is copied to your clipboard: https://github.com/python/cpython/blob/c82b7f332aff606af6c9c163da75f1e86514125e/Doc/Makefile#L1-L4

Export tables to an excel spreadsheet in same directory

For people who find this via search engines, you do not need VBA. You can just:

1.) select the query or table with your mouse
2.) click export data from the ribbon
3.) click excel from the export subgroup
4.) follow the wizard to select the output file and location.

How to center an unordered list?

From your post, I understand that you cannot set the width to your li.

How about this?

_x000D_
_x000D_
ul {
  border:2px solid red;
  display:inline-block;
}

li {
  display:inline;
  padding:0 30%; /* try adjusting the side % to give a feel of center aligned.*/
}
_x000D_
<ul>
    <li>Hello</li>
    <li>Hezkdhkfskdhfkllo</li>
    <li>Hello</li>
</ul>
_x000D_
_x000D_
_x000D_

Here's a demo. http://codepen.io/anon/pen/HhBwx

Browser detection in JavaScript?

Below code snippet will show how how you can show UI elemnts depends on IE version and browser

$(document).ready(function () {

var msiVersion = GetMSIieversion();
if ((msiVersion <= 8) && (msiVersion != false)) {

    //Show UI elements specific to IE version 8 or low

    } else {
    //Show UI elements specific to IE version greater than 8 and for other browser other than IE,,ie..Chrome,Mozila..etc
    }
}
);

Below code will give how we can get IE version

function GetMSIieversion() {

var ua = window.navigator.userAgent;
var msie = ua.indexOf('MSIE ');
if (msie > 0) {
    // IE 10 or older => return version number
    return parseInt(ua.substring(msie + 5, ua.indexOf('.', msie)), 10);
}

var trident = ua.indexOf('Trident/');
if (trident > 0) {
    // IE 11 => return version number
    var rv = ua.indexOf('rv:');
    return parseInt(ua.substring(rv + 3, ua.indexOf('.', rv)), 10);
}

var edge = ua.indexOf('Edge/');
if (edge > 0) {
    // Edge (IE 12+) => return version number
    return parseInt(ua.substring(edge + 5, ua.indexOf('.', edge)), 10);
}

// other browser like Chrome,Mozila..etc
return false;

}

how to convert String into Date time format in JAVA?

With SimpleDateFormat. And steps are -

  1. Create your date pattern string
  2. Create SimpleDateFormat Object
  3. And parse with it.
  4. It will return Date Object.

Using ffmpeg to encode a high quality video

A couple of things:

  • You need to set the video bitrate. I have never used minrate and maxrate so I don't know how exactly they work, but by setting the bitrate using the -b switch, I am able to get high quality video. You need to come up with a bitrate that offers a good tradeoff between compression and video quality. You may have to experiment with this because it all depends on the frame size, frame rate and the amount of motion in the content of your video. Keep in mind that DVD tends to be around 4-5 Mbit/s on average for 720x480, so I usually start from there and decide whether I need more or less and then just experiment. For example, you could add -b 5000k to the command line to get more or less DVD video bitrate.

  • You need to specify a video codec. If you don't, ffmpeg will default to MPEG-1 which is quite old and does not provide near the amount of compression as MPEG-4 or H.264. If your ffmpeg version is built with libx264 support, you can specify -vcodec libx264 as part of the command line. Otherwise -vcodec mpeg4 will also do a better job than MPEG-1, but not as well as x264.

  • There are a lot of other advanced options that will help you squeeze out the best quality at the lowest bitrates. Take a look here for some examples.

ImportError: cannot import name NUMPY_MKL

I don't have enough reputation to comment but I want to add, that the cp number of the .whl file stands for your python version.

cp35 -> Python 3.5.x

cp36 -> Python 3.6.x

cp37 -> Python 3.7.x

I think it's pretty obvious but still I wasted almost an hour because of this and maybe other people struggle with that, too.

So for me worked version cp36 that I downloaded here: https://www.lfd.uci.edu/~gohlke/pythonlibs/#numpy since I am using Python 3.6.8.

Then I uninstalled numpy:

pip uninstall numpy 

Then I installed numpy+mkl:

pip install <destination of your .whl file>

Excel Formula which places date/time in cell when data is entered in another cell in the same row

Another way to do this is described below.

First, turn on iterative calculations on under File - Options - Formulas - Enable Iterative Calculation. Then set maximum iterations to 1000.

After doing this, use the following formula.

=If(D55="","",IF(C55="",NOW(),C55))

Once anything is typed into cell D55 (for this example) then C55 populates today's date and/or time depending on the cell format. This date/time will not change again even if new data is entered into cell C55 so it shows the date/time that the data was entered originally.

This is a circular reference formula so you will get a warning about it every time you open the workbook. Regardless, the formula works and is easy to use anywhere you would like in the worksheet.

Can overridden methods differ in return type?

Broadly speaking yes return type of overriding method can be different. But it's not straight forward as there are some cases involved in this.

Case 1: If the return type is a primitive data type or void.

Output: If the return type is void or primitive then the data type of parent class method and overriding method should be the same. e.g. if the return type is int, float, string then it should be same

Case 2: If the return type is derived data type:

Output: If the return type of the parent class method is derived type then the return type of the overriding method is the same derived data type of subclass to the derived data type. e.g. Suppose I have a class A, B is a subclass to A, C is a subclass to B and D is a subclass to C; then if the super class is returning type A then the overriding method in subclass can return either A, or B/C/D type i.e. its sub types. This is also called as covariance.

M_PI works with math.h but not with cmath in Visual Studio

According to Microsoft documentation about Math Constants:

The file ATLComTime.h includes math.h when your project is built in Release mode. If you use one or more of the math constants in a project that also includes ATLComTime.h, you must define _USE_MATH_DEFINES before you include ATLComTime.h.

File ATLComTime.h may be included indirectly in your project. In my case one possible order of including was the following:

project's "stdafx.h" ? <afxdtctl.h> ? <afxdisp.h> ? <ATLComTime.h> ? <math.h>

How to do a for loop in windows command line?

This may help you find what you're looking for... Batch script loop

My answer is as follows:

@echo off
:start
set /a var+=1
if %var% EQU 100 goto end
:: Code you want to run goes here
goto start

:end
echo var has reached %var%.
pause
exit

The first set of commands under the start label loops until a variable, %var% reaches 100. Once this happens it will notify you and allow you to exit. This code can be adapted to your needs by changing the 100 to 17 and putting your code or using a call command followed by the batch file's path (Shift+Right Click on file and select "Copy as Path") where the comment is placed.

What does "<>" mean in Oracle

It means 'not equal to'. So you're filtering out records where ordid is 605. Overall you're looking for any records which have the same prodid and qty values as those assigned to ordid 605, but which are for a different order.

PHP: Call to undefined function: simplexml_load_string()

If the XML module is not installed, install it.

Current version 5.6 on ubuntu 14.04:

sudo apt-get install php5.6-xml

And don't forget to run sudo service apache2 restart command after it

Zulhilmi Zainudi

How to solve a pair of nonlinear equations using Python?

An alternative to fsolve is root:

import numpy as np
from scipy.optimize import root    

def your_funcs(X):

    x, y = X
    # all RHS have to be 0
    f = [x + y**2 - 4,
         np.exp(x) + x * y - 3]

    return f

sol = root(your_funcs, [1.0, 1.0])
print(sol.x)

This will print

[0.62034452 1.83838393]

If you then check

print(your_funcs(sol.x))

you obtain

[4.4508396968012676e-11, -1.0512035686360832e-11]

confirming that the solution is correct.

Responsive Google Map?

Add this to your initialize function:

<script type="text/javascript">

function initialize() {

  var map = new google.maps.Map(document.getElementById("map-canvas"), mapOptions);

  // Resize stuff...
  google.maps.event.addDomListener(window, "resize", function() {
    var center = map.getCenter();
    google.maps.event.trigger(map, "resize");
    map.setCenter(center); 
  });

}

</script>

What is the difference between buffer and cache memory in Linux?

Buffers are associated with a specific block device, and cover caching of filesystem metadata as well as tracking in-flight pages. The cache only contains parked file data. That is, the buffers remember what's in directories, what file permissions are, and keep track of what memory is being written from or read to for a particular block device. The cache only contains the contents of the files themselves.

quote link

How do I deal with "signed/unsigned mismatch" warnings (C4018)?

It's all in your things.size() type. It isn't int, but size_t (it exists in C++, not in C) which equals to some "usual" unsigned type, i.e. unsigned int for x86_32.

Operator "less" (<) cannot be applied to two operands of different sign. There's just no such opcodes, and standard doesn't specify, whether compiler can make implicit sign conversion. So it just treats signed number as unsigned and emits that warning.

It would be correct to write it like

for (size_t i = 0; i < things.size(); ++i) { /**/ }

or even faster

for (size_t i = 0, ilen = things.size(); i < ilen; ++i) { /**/ }

Create a new object from type parameter in generic class

This is what I do to retain type info:

class Helper {
   public static createRaw<T>(TCreator: { new (): T; }, data: any): T
   {
     return Object.assign(new TCreator(), data);
   }
   public static create<T>(TCreator: { new (): T; }, data: T): T
   {
      return this.createRaw(TCreator, data);
   }
}

...

it('create helper', () => {
    class A {
        public data: string;
    }
    class B {
        public data: string;
        public getData(): string {
            return this.data;
        }
    }
    var str = "foobar";

    var a1 = Helper.create<A>(A, {data: str});
    expect(a1 instanceof A).toBeTruthy();
    expect(a1.data).toBe(str);

    var a2 = Helper.create(A, {data: str});
    expect(a2 instanceof A).toBeTruthy();
    expect(a2.data).toBe(str);

    var b1 = Helper.createRaw(B, {data: str});
    expect(b1 instanceof B).toBeTruthy();
    expect(b1.data).toBe(str);
    expect(b1.getData()).toBe(str);

});

Skipping Incompatible Libraries at compile

Normally, that is not an error per se; it is a warning that the first file it found that matches the -lPI-Http argument to the compiler/linker is not valid. The error occurs when no other library can be found with the right content.

So, you need to look to see whether /dvlpmnt/libPI-Http.a is a library of 32-bit object files or of 64-bit object files - it will likely be 64-bit if you are compiling with the -m32 option. Then you need to establish whether there is an alternative libPI-Http.a or libPI-Http.so file somewhere else that is 32-bit. If so, ensure that the directory that contains it is listed in a -L/some/where argument to the linker. If not, then you will need to obtain or build a 32-bit version of the library from somewhere.

To establish what is in that library, you may need to do:

mkdir junk
cd junk
ar x /dvlpmnt/libPI-Http.a
file *.o
cd ..
rm -fr junk

The 'file' step tells you what type of object files are in the archive. The rest just makes sure you don't make a mess that can't be easily cleaned up.

Twitter Bootstrap - how to center elements horizontally or vertically

bootstrap 4 + Flex solve this

you can use

_x000D_
_x000D_
<div class="d-flex justify-content-center align-items-center">_x000D_
    <button type="submit" class="btn btn-primary">Create</button>_x000D_
</div>
_x000D_
_x000D_
_x000D_

it should center centent horizontaly and verticaly

VSCode: How to Split Editor Vertically

The key bindings has been changed with version 1.20:

SHIFT+ALT+0 for Linux.

Presumably the same works for Windows also and CMD+OPT+0 for Mac.

How to get a table creation script in MySQL Workbench?

Not sure if I fully understood your problem, but if it's just about creating export scripts, you should forward engineer to SQL script - Ctrl + Shift + G or File -> Export -> first option.

CSS3 :unchecked pseudo-class

The way I handled this was switching the className of a label based on a condition. This way you only need one label and you can have different classes for different states... Hope that helps!

How do you copy a record in a SQL table but swap out the unique id of the new row?

You can do like this:

INSERT INTO DENI/FRIEN01P 
SELECT 
   RCRDID+112,
   PROFESION,
   NAME,
   SURNAME,
   AGE, 
   RCRDTYP, 
   RCRDLCU, 
   RCRDLCT, 
   RCRDLCD 
FROM 
   FRIEN01P      

There instead of 112 you should put a number of the maximum id in table DENI/FRIEN01P.

Best way to reset an Oracle sequence to the next value in an existing column?

If you can count on having a period of time where the table is in a stable state with no new inserts going on, this should do it (untested):

DECLARE
  last_used  NUMBER;
  curr_seq   NUMBER;
BEGIN
  SELECT MAX(pk_val) INTO last_used FROM your_table;

  LOOP
    SELECT your_seq.NEXTVAL INTO curr_seq FROM dual;
    IF curr_seq >= last_used THEN EXIT;
    END IF;
  END LOOP;
END;

This enables you to get the sequence back in sync with the table, without dropping/recreating/re-granting the sequence. It also uses no DDL, so no implicit commits are performed. Of course, you're going to have to hunt down and slap the folks who insist on not using the sequence to populate the column...

Can't connect to MySQL server on 'localhost' (10061) after Installation

Turn off firewall and restart mysql server. then turn on firewall. It's the easy way! just try it

How do MySQL indexes work?

The first thing you must know is that indexes are a way to avoid scanning the full table to obtain the result that you're looking for.

There are different kinds of indexes and they're implemented in the storage layer, so there's no standard between them and they also depend on the storage engine that you're using.

InnoDB and the B+Tree index

For InnoDB, the most common index type is the B+Tree based index, that stores the elements in a sorted order. Also, you don't have to access the real table to get the indexed values, which makes your query return way faster.

The "problem" about this index type is that you have to query for the leftmost value to use the index. So, if your index has two columns, say last_name and first_name, the order that you query these fields matters a lot.

So, given the following table:

CREATE TABLE person (
    last_name VARCHAR(50) NOT NULL,
    first_name VARCHAR(50) NOT NULL,
    INDEX (last_name, first_name)
);

This query would take advantage of the index:

SELECT last_name, first_name FROM person
WHERE last_name = "John" AND first_name LIKE "J%"

But the following one would not

SELECT last_name, first_name FROM person WHERE first_name = "Constantine"

Because you're querying the first_name column first and it's not the leftmost column in the index.

This last example is even worse:

SELECT last_name, first_name FROM person WHERE first_name LIKE "%Constantine"

Because now, you're comparing the rightmost part of the rightmost field in the index.

The hash index

This is a different index type that unfortunately, only the memory backend supports. It's lightning fast but only useful for full lookups, which means that you can't use it for operations like >, < or LIKE.

Since it only works for the memory backend, you probably won't use it very often. The main case I can think of right now is the one that you create a temporary table in the memory with a set of results from another select and perform a lot of other selects in this temporary table using hash indexes.

If you have a big VARCHAR field, you can "emulate" the use of a hash index when using a B-Tree, by creating another column and saving a hash of the big value on it. Let's say you're storing a url in a field and the values are quite big. You could also create an integer field called url_hash and use a hash function like CRC32 or any other hash function to hash the url when inserting it. And then, when you need to query for this value, you can do something like this:

SELECT url FROM url_table WHERE url_hash=CRC32("http://gnu.org");

The problem with the above example is that since the CRC32 function generates a quite small hash, you'll end up with a lot of collisions in the hashed values. If you need exact values, you can fix this problem by doing the following:

SELECT url FROM url_table 
WHERE url_hash=CRC32("http://gnu.org") AND url="http://gnu.org";

It's still worth to hash things even if the collision number is high cause you'll only perform the second comparison (the string one) against the repeated hashes.

Unfortunately, using this technique, you still need to hit the table to compare the url field.

Wrap up

Some facts that you may consider every time you want to talk about optimization:

  1. Integer comparison is way faster than string comparison. It can be illustrated with the example about the emulation of the hash index in InnoDB.

  2. Maybe, adding additional steps in a process makes it faster, not slower. It can be illustrated by the fact that you can optimize a SELECT by splitting it into two steps, making the first one store values in a newly created in-memory table, and then execute the heavier queries on this second table.

MySQL has other indexes too, but I think the B+Tree one is the most used ever and the hash one is a good thing to know, but you can find the other ones in the MySQL documentation.

I highly recommend you to read the "High Performance MySQL" book, the answer above was definitely based on its chapter about indexes.

What does the @ symbol before a variable name mean in C#?

An important point that the other answers forgot, is that "@keyword" is compiled into "keyword" in the CIL.

So if you have a framework that was made in, say, F#, which requires you to define a class with a property named "class", you can actually do it.

It is not that useful in practice, but not having it would prevent C# from some forms of language interop.

I usually see it used not for interop, but to avoid the keyword restrictions (usually on local variable names, where this is the only effect) ie.

private void Foo(){
   int @this = 2;
}

but I would strongly discourage that! Just find another name, even if the 'best' name for the variable is one of the reserved names.

The 'json' native gem requires installed build tools

My gem version 2.0.3 and I was getting the same issue. This command resolved it:

gem install json --platform=ruby --verbose

Create Windows service from executable

I created the cross-platform Service Manager software a few years back so that I could start PHP and other scripting languages as system services on Windows, Mac, and Linux OSes:

https://github.com/cubiclesoft/service-manager

Service Manager is a set of precompiled binaries that install and manage a system service on the target OS using nearly identical command-line options (source code also available). Each platform does have subtle differences but the core features are mostly normalized.

If the child process dies, Service Manager automatically restarts it.

Processes that are started with Service Manager should periodically watch for two notification files to handle restart and reload requests but they don't necessarily have to do that. Service Manager will force restart the child process if it doesn't respond in a timely fashion to controlled restart/reload requests.

How to gettext() of an element in Selenium Webdriver

You need to print the result of the getText(). You're currently printing the object TxtBoxContent.

getText() will only get the inner text of an element. To get the value, you need to use getAttribute().

WebElement TxtBoxContent = driver.findElement(By.id(WebelementID));
System.out.println("Printing " + TxtBoxContent.getAttribute("value"));

Insert multiple rows into single column

INSERT INTO hr.employees (location_id) VALUE (1000) WHERE first_name LIKE '%D%';

let me know if there is any problem in this statement.

How can I use pointers in Java?

All objects in java are passed to functions by reference copy except primitives.

In effect, this means that you are sending a copy of the pointer to the original object rather than a copy of the object itself.

Please leave a comment if you want an example to understand this.

swift UITableView set rowHeight

Make sure Your TableView Delegate are working as well. if not then in your story board or in .xib press and hold Control + right click on tableView drag and Drop to your Current ViewController. swift 2.0

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return 60.0;
}

How to query GROUP BY Month in a Year

For MS SQL you can do this.

    select  CAST(DATEPART(MONTH, DateTyme) as VARCHAR) +'/'+ 
CAST(DATEPART(YEAR, DateTyme) as VARCHAR) as 'Date' from #temp
    group by Name, CAST(DATEPART(MONTH, DateTyme) as VARCHAR) +'/'+
 CAST(DATEPART(YEAR, DateTyme) as VARCHAR) 

JAVA_HOME is set to an invalid directory:

First try removing the '\bin' from the path and set the home directory JAVA_HOME as below: JAVA_HOME : C:\Program Files\Java\jdk1.8.0_131

Second Update System PATH:

  1. In “Environment Variables” window under “System variables” select Path
  2. Click on “Edit…”
  3. In “Edit environment variable” window click “New”
  4. Type in %JAVA_HOME%\bin

Third restart your docker.

Refer to the link for setting the java path in windows.

Can you have if-then-else logic in SQL?

--Similar answer as above for the most part. Code included to test

DROP TABLE table1
GO
CREATE TABLE table1 (project int, customer int, company int, product int, price money)
GO
INSERT INTO table1 VALUES (1,0,50, 100, 40),(1,0,20, 200, 55),(1,10,30,300, 75),(2,10,30,300, 75)
GO
SELECT TOP 1 WITH TIES product
        , price
        , CASE WhereFound WHEN 1 THEN 'Project'
                WHEN 2 THEN 'Customer'
                WHEN 3 THEN 'Company'
            ELSE 'No Match'
            END AS Source
FROM 
    (
     SELECT product, price, 1 as WhereFound FROM table1 where project = 11
     UNION ALL
     SELECT product, price, 2 FROM table1 where customer = 0
     UNION ALL
     SELECT product, price, 3 FROM table1 where company = 30
    ) AS tbl
ORDER BY WhereFound ASC

Force flushing of output to a file while bash script is still running

You can use tee to write to the file without the need for flushing.

/homedir/MyScript 2>&1 | tee some_log.log > /dev/null

How to install SQL Server Management Studio 2012 (SSMS) Express?

Easiest way to install MSSQL 2012 MS SQL INSTALLATION

Here i am showing the easiest way to install ms sql 2012.

My opinion is the installation will be easier with windows 8.1 rather than windows 7.

This is my personnal opinion only.

We can install in windows 7 as well.

The steps to be followed:

Download any one of the link using the following URL

http://www.microsoft.com/en-us/download/details.aspx?id=43351

SQLEXPRWT_x86_ENU.exe or SQLEXPRWT_x64_ENU.exe

http://www.microsoft.com/en-us/download/details.aspx?id=42299

SQLEXPRWT_x86_ENU.exe or SQLEXPRWT_x64_ENU.exe

Right click on .exe file and run it

We should leave everything default while installing.

During installation, there will be 2 options:

1)If you are New user,then click on new sql-server stand alone application.

2)If you have already MS SQL application then you can upgrade by using the other option.

Then accept the Licence terms and click Next.

Now you will move on to Product Updates and press next then Setup support rules.

After this Feature selection.According to me we can check all the boxes except localdb.

Next it will take you to Instance Configuration where you should select Named Instance as

"SQLEXPRESS".

Then go to Server Configuration and press next.

Now Database engine configuration:

Authentication Mode:we can click on any one that is windows authentication mode or mixed.

Windows authentication mode (default for windows).

Mixed authentication mode:then should create username and password.

Then move on Error reporting,we can move further by clicking next to install process.

Finally we can see the Complete windows by showing the products added .

We can close and run the MSSQL server.

I hope it's useful.

Regards

Ramya

Extract subset of key-value pairs from Python dictionary object?

This answer uses a dictionary comprehension similar to the selected answer, but will not except on a missing item.

python 2 version:

{k:v for k, v in bigDict.iteritems() if k in ('l', 'm', 'n')}

python 3 version:

{k:v for k, v in bigDict.items() if k in ('l', 'm', 'n')}

Multiple WHERE clause in Linq

@Jon: Jon, are you saying using multiple where clauses e.g.

var query = from r in tempData.AsEnumerable()
            where r.Field<string>("UserName") != "XXXX" 
            where r.Field<string>("UserName") != "YYYY"
            select r;

is more restictive than using

var query = from r in tempData.AsEnumerable()
            where r.Field<string>("UserName") != "XXXX" && r.Field<string>("UserName") != "YYYY"
            select r;

I think they are equivalent as far as the result goes.

However, I haven't tested, if using multiple where in the first example cause in 2 subqueries, i.e. .Where(r=>r.UserName!="XXXX").Where(r=>r.UserName!="YYYY) or the LINQ translator is smart enought to execute .Where(r=>r.UserName!="XXXX" && r.UsernName!="YYYY")

Plotting time-series with Date labels on x-axis

1) Since the times are dates be sure to use "Date" class, not "POSIXct" or "POSIXlt". See R News 4/1 for advice and try this where Lines is defined in the Note at the end. No packages are used here.

dm <- read.table(text = Lines, header = TRUE)
dm$Date <- as.Date(dm$Date, "%m/%d/%Y")
plot(Visits ~ Date, dm, xaxt = "n", type = "l")
axis(1, dm$Date, format(dm$Date, "%b %d"), cex.axis = .7)

The use of text = Lines is just to keep the example self-contained and in reality it would be replaced with something like "myfile.dat" . (continued after image)

screenshot

2) Since this is a time series you may wish to use a time series representation giving slightly simpler code:

library(zoo)

z <- read.zoo(text = Lines, header = TRUE, format = "%m/%d/%Y")
plot(z, xaxt = "n")
axis(1, dm$Date, format(dm$Date, "%b %d"), cex.axis = .7)

Depending on what you want the plot to look like it may be sufficient just to use plot(Visits ~ Date, dm) in the first case or plot(z) in the second case suppressing the axis command entirely. It could also be done using xyplot.zoo

library(lattice)
xyplot(z)

or autoplot.zoo:

library(ggplot2)
autoplot(z)

Note:

Lines <- "Date            Visits
11/1/2010   696537
11/2/2010   718748
11/3/2010   799355
11/4/2010   805800
11/5/2010   701262
11/6/2010   531579
11/7/2010   690068
11/8/2010   756947
11/9/2010   718757
11/10/2010  701768
11/11/2010  820113
11/12/2010  645259"

Python - Move and overwrite files and folders

I had a similar problem. I wanted to move files and folder structures and overwrite existing files, but not delete anything which is in the destination folder structure.

I solved it by using os.walk(), recursively calling my function and using shutil.move() on files which I wanted to overwrite and folders which did not exist.

It works like shutil.move(), but with the benefit that existing files are only overwritten, but not deleted.

import os
import shutil

def moverecursively(source_folder, destination_folder):
    basename = os.path.basename(source_folder)
    dest_dir = os.path.join(destination_folder, basename)
    if not os.path.exists(dest_dir):
        shutil.move(source_folder, destination_folder)
    else:
        dst_path = os.path.join(destination_folder, basename)
        for root, dirs, files in os.walk(source_folder):
            for item in files:
                src_path = os.path.join(root, item)
                if os.path.exists(dst_file):
                    os.remove(dst_file)
                shutil.move(src_path, dst_path)
            for item in dirs:
                src_path = os.path.join(root, item)
                moverecursively(src_path, dst_path)

src absolute path problem

<img src="file://C:/wamp/www/site/img/mypicture.jpg"/>

How to determine if string contains specific substring within the first X characters

shorter version:

found = Value1.StartsWith("abc");

sorry, but I am a stickler for 'less' code.


Given the edit of the questioner I would actually go with something that accepted an offset, this may in fact be a Great place to an Extension method that overloads StartsWith

public static class StackOverflowExtensions
{
    public static bool StartsWith(this String val, string findString, int count)
    {
        return val.Substring(0, count).Contains(findString);
    }
}

How to debug an apache virtual host configuration?

I found my own mistake, I did not add log file name: ErrorLog /var/log/apache2
And this path: Directory "/usr/share/doc/" Did not contain website sources.

After I changed these two, all worked. Interestingly, apache did not issue any errors, just did not open my website silently on my Mac OS Sierra.

JavaScript code to stop form submission

Simply do it....

<form>
<!-- Your Input Elements -->
</form>

and here goes your JQuery

$(document).on('submit', 'form', function(e){
    e.preventDefault();
    //your code goes here
    //100% works
    return;
});

Convert date to UTC using moment.js

Read this documentation of moment.js here. See below example and output where I convert GMT time to local time (my zone is IST) and then I convert local time to GMT.

// convert GMT to local time
console.log('Server time:' + data[i].locationServerTime)
let serv_utc = moment.utc(data[i].locationServerTime, "YYYY-MM-DD HH:mm:ss").toDate();
console.log('serv_utc:' + serv_utc)
data[i].locationServerTime = moment(serv_utc,"YYYY-MM-DD HH:mm:ss").tz(self.zone_name).format("YYYY-MM-DD HH:mm:ss");
console.log('Converted to local time:' + data[i].locationServerTime)

// convert local time to GMT
console.log('local time:' + data[i].locationServerTime)
let serv_utc = moment(data[i].locationServerTime, "YYYY-MM-DD HH:mm:ss").toDate();
console.log('serv_utc:' + serv_utc)
data[i].locationServerTime = moment.utc(serv_utc,"YYYY-MM-DD HH:mm:ss").format("YYYY-MM-DD HH:mm:ss");
console.log('Converted to server time:' + data[i].locationServerTime)

Output is

Server time:2019-12-19 09:28:13
serv_utc:Thu Dec 19 2019 14:58:13 GMT+0530 (India Standard Time)
Converted to local time:2019-12-19 14:58:13
local time:2019-12-19 14:58:13
serv_utc:Thu Dec 19 2019 14:58:13 GMT+0530 (India Standard Time)
Converted to server time:2019-12-19 09:28:13

Detect if a browser in a mobile device (iOS/Android phone/tablet) is used

Don't detect mobile devices, go for stationary ones instead.

Nowadays (2016) there is a way to detect dots per inch/cm/px that seems to work in most modern browsers (see http://caniuse.com/#feat=css-media-resolution). I needed a method to distinguish between a relatively small screen, orientation didn't matter, and a stationary computer monitor.

Because many mobile browsers don't support this, one can write the general css code for all cases and use this exception for large screens:

@media (max-resolution: 1dppx) {
    /* ... */
}

Both Windows XP and 7 have the default setting of 1 dot per pixel (or 96dpi). I don't know about other operating systems, but this works really well for my needs.

Edit: dppx doesn't seem to work in Internet Explorer.. use (96)dpi instead.

Difference between Visibility.Collapsed and Visibility.Hidden

The difference is that Visibility.Hidden hides the control, but reserves the space it occupies in the layout. So it renders whitespace instead of the control. Visibilty.Collapsed does not render the control and does not reserve the whitespace. The space the control would take is 'collapsed', hence the name.

The exact text from the MSDN:

Collapsed: Do not display the element, and do not reserve space for it in layout.

Hidden: Do not display the element, but reserve space for the element in layout.

Visible: Display the element.

See: http://msdn.microsoft.com/en-us/library/system.windows.visibility.aspx

Get source jar files attached to Eclipse for Maven-managed dependencies

in my version of Eclipse helios with m2Eclipse there is no

window --> maven --> Download Artifact Sources (select check)

Under window is only "new window", "new editor" "open perspective" etc.

If you right click on your project, then chose maven--> download sources

Nothing happens. no sources get downloaded, no pom files get updated, no window pops up asking which sources.

Doing mvn xxx outside of eclipse is dangerous - some commands dont work with m2ecilpse - I did that once and lost the entire project, had to reinstall eclipse and start from scratch.

Im still looking for a way to get ecilpse and maven to find and use the source of external jars like servlet-api.

How can I count the rows with data in an Excel sheet?

With formulas, what you can do is:

  • in a new column (say col D - cell D2), add =COUNTA(A2:C2)
  • drag this formula till the end of your data (say cell D4 in our example)
  • add a last formula to sum it up (e.g in cell D5): =SUM(D2:D4)

How to open an Excel file in C#?

open Excel file

System.Diagnostics.Process.Start(@"c:\document.xls");

unable to install pg gem

I hadn't postgresql installed, so I just installed it using

sudo apt-get install postgresql postgresql-server-dev-9.1

on Ubuntu 12.04.

This solved it.


Update:

Use the latest version:

sudo apt-get install postgresql-9.3 postgresql-server-dev-9.3

How to increase Bootstrap Modal Width?

You can choose between modal-lg and modal-xl classes or if you want custom width then, set max-width property with inline css. For example,

<div class="modal-dialog modal-xl" role="document">

or

<div class="modal-dialog" style="max-width: 80%;" role="document">

javax.crypto.IllegalBlockSizeException : Input length must be multiple of 16 when decrypting with padded cipher

A few comments:

import sun.misc.*; Don't do this. It is non-standard and not guaranteed to be the same between implementations. There are other libraries with Base64 conversion available.

byte[] encVal = c.doFinal(Data.getBytes()); You are relying on the default character encoding here. Always specify what character encoding you are using: byte[] encVal = c.doFinal(Data.getBytes("UTF-8")); Defaults might be different in different places.

As @thegrinner pointed out, you need to explicitly check the length of your byte arrays. If there is a discrepancy, then compare them byte by byte to see where the difference is creeping in.

How to convert a column number (e.g. 127) into an Excel column (e.g. AA)

I wanted to throw in my static class I use, for interoping between col index and col Label. I use a modified accepted answer for my ColumnLabel Method

public static class Extensions
{
    public static string ColumnLabel(this int col)
    {
        var dividend = col;
        var columnLabel = string.Empty;
        int modulo;

        while (dividend > 0)
        {
            modulo = (dividend - 1) % 26;
            columnLabel = Convert.ToChar(65 + modulo).ToString() + columnLabel;
            dividend = (int)((dividend - modulo) / 26);
        } 

        return columnLabel;
    }
    public static int ColumnIndex(this string colLabel)
    {
        // "AD" (1 * 26^1) + (4 * 26^0) ...
        var colIndex = 0;
        for(int ind = 0, pow = colLabel.Count()-1; ind < colLabel.Count(); ++ind, --pow)
        {
            var cVal = Convert.ToInt32(colLabel[ind]) - 64; //col A is index 1
            colIndex += cVal * ((int)Math.Pow(26, pow));
        }
        return colIndex;
    }
}

Use this like...

30.ColumnLabel(); // "AD"
"AD".ColumnIndex(); // 30

Fastest way to check a string contain another substring in JavaScript?

The Fastest

  1. (ES6) includes
    var string = "hello",
    substring = "lo";
    string.includes(substring);
  1. ES5 and older indexOf
    var string = "hello",
    substring = "lo";
    string.indexOf(substring) !== -1;

http://jsben.ch/9cwLJ

enter image description here

Multiple glibc libraries on a single host

Setup 1: compile your own glibc without dedicated GCC and use it

This setup might work and is quick as it does not recompile the whole GCC toolchain, just glibc.

But it is not reliable as it uses host C runtime objects such as crt1.o, crti.o, and crtn.o provided by glibc. This is mentioned at: https://sourceware.org/glibc/wiki/Testing/Builds?action=recall&rev=21#Compile_against_glibc_in_an_installed_location Those objects do early setup that glibc relies on, so I wouldn't be surprised if things crashed in wonderful and awesomely subtle ways.

For a more reliable setup, see Setup 2 below.

Build glibc and install locally:

export glibc_install="$(pwd)/glibc/build/install"

git clone git://sourceware.org/git/glibc.git
cd glibc
git checkout glibc-2.28
mkdir build
cd build
../configure --prefix "$glibc_install"
make -j `nproc`
make install -j `nproc`

Setup 1: verify the build

test_glibc.c

#define _GNU_SOURCE
#include <assert.h>
#include <gnu/libc-version.h>
#include <stdatomic.h>
#include <stdio.h>
#include <threads.h>

atomic_int acnt;
int cnt;

int f(void* thr_data) {
    for(int n = 0; n < 1000; ++n) {
        ++cnt;
        ++acnt;
    }
    return 0;
}

int main(int argc, char **argv) {
    /* Basic library version check. */
    printf("gnu_get_libc_version() = %s\n", gnu_get_libc_version());

    /* Exercise thrd_create from -pthread,
     * which is not present in glibc 2.27 in Ubuntu 18.04.
     * https://stackoverflow.com/questions/56810/how-do-i-start-threads-in-plain-c/52453291#52453291 */
    thrd_t thr[10];
    for(int n = 0; n < 10; ++n)
        thrd_create(&thr[n], f, NULL);
    for(int n = 0; n < 10; ++n)
        thrd_join(thr[n], NULL);
    printf("The atomic counter is %u\n", acnt);
    printf("The non-atomic counter is %u\n", cnt);
}

Compile and run with test_glibc.sh:

#!/usr/bin/env bash
set -eux
gcc \
  -L "${glibc_install}/lib" \
  -I "${glibc_install}/include" \
  -Wl,--rpath="${glibc_install}/lib" \
  -Wl,--dynamic-linker="${glibc_install}/lib/ld-linux-x86-64.so.2" \
  -std=c11 \
  -o test_glibc.out \
  -v \
  test_glibc.c \
  -pthread \
;
ldd ./test_glibc.out
./test_glibc.out

The program outputs the expected:

gnu_get_libc_version() = 2.28
The atomic counter is 10000
The non-atomic counter is 8674

Command adapted from https://sourceware.org/glibc/wiki/Testing/Builds?action=recall&rev=21#Compile_against_glibc_in_an_installed_location but --sysroot made it fail with:

cannot find /home/ciro/glibc/build/install/lib/libc.so.6 inside /home/ciro/glibc/build/install

so I removed it.

ldd output confirms that the ldd and libraries that we've just built are actually being used as expected:

+ ldd test_glibc.out
        linux-vdso.so.1 (0x00007ffe4bfd3000)
        libpthread.so.0 => /home/ciro/glibc/build/install/lib/libpthread.so.0 (0x00007fc12ed92000)
        libc.so.6 => /home/ciro/glibc/build/install/lib/libc.so.6 (0x00007fc12e9dc000)
        /home/ciro/glibc/build/install/lib/ld-linux-x86-64.so.2 => /lib64/ld-linux-x86-64.so.2 (0x00007fc12f1b3000)

The gcc compilation debug output shows that my host runtime objects were used, which is bad as mentioned previously, but I don't know how to work around it, e.g. it contains:

COLLECT_GCC_OPTIONS=/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/crt1.o

Setup 1: modify glibc

Now let's modify glibc with:

diff --git a/nptl/thrd_create.c b/nptl/thrd_create.c
index 113ba0d93e..b00f088abb 100644
--- a/nptl/thrd_create.c
+++ b/nptl/thrd_create.c
@@ -16,11 +16,14 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */

+#include <stdio.h>
+
 #include "thrd_priv.h"

 int
 thrd_create (thrd_t *thr, thrd_start_t func, void *arg)
 {
+  puts("hacked");
   _Static_assert (sizeof (thr) == sizeof (pthread_t),
                   "sizeof (thr) != sizeof (pthread_t)");

Then recompile and re-install glibc, and recompile and re-run our program:

cd glibc/build
make -j `nproc`
make -j `nproc` install
./test_glibc.sh

and we see hacked printed a few times as expected.

This further confirms that we actually used the glibc that we compiled and not the host one.

Tested on Ubuntu 18.04.

Setup 2: crosstool-NG pristine setup

This is an alternative to setup 1, and it is the most correct setup I've achieved far: everything is correct as far as I can observe, including the C runtime objects such as crt1.o, crti.o, and crtn.o.

In this setup, we will compile a full dedicated GCC toolchain that uses the glibc that we want.

The only downside to this method is that the build will take longer. But I wouldn't risk a production setup with anything less.

crosstool-NG is a set of scripts that downloads and compiles everything from source for us, including GCC, glibc and binutils.

Yes the GCC build system is so bad that we need a separate project for that.

This setup is only not perfect because crosstool-NG does not support building the executables without extra -Wl flags, which feels weird since we've built GCC itself. But everything seems to work, so this is only an inconvenience.

Get crosstool-NG, configure and build it:

git clone https://github.com/crosstool-ng/crosstool-ng
cd crosstool-ng
git checkout a6580b8e8b55345a5a342b5bd96e42c83e640ac5
export CT_PREFIX="$(pwd)/.build/install"
export PATH="/usr/lib/ccache:${PATH}"
./bootstrap
./configure --enable-local
make -j `nproc`
./ct-ng x86_64-unknown-linux-gnu
./ct-ng menuconfig
env -u LD_LIBRARY_PATH time ./ct-ng build CT_JOBS=`nproc`

The build takes about thirty minutes to two hours.

The only mandatory configuration option that I can see, is making it match your host kernel version to use the correct kernel headers. Find your host kernel version with:

uname -a

which shows me:

4.15.0-34-generic

so in menuconfig I do:

  • Operating System
    • Version of linux

so I select:

4.14.71

which is the first equal or older version. It has to be older since the kernel is backwards compatible.

Setup 2: optional configurations

The .config that we generated with ./ct-ng x86_64-unknown-linux-gnu has:

CT_GLIBC_V_2_27=y

To change that, in menuconfig do:

  • C-library
  • Version of glibc

save the .config, and continue with the build.

Or, if you want to use your own glibc source, e.g. to use glibc from the latest git, proceed like this:

  • Paths and misc options
    • Try features marked as EXPERIMENTAL: set to true
  • C-library
    • Source of glibc
      • Custom location: say yes
      • Custom location
        • Custom source location: point to a directory containing your glibc source

where glibc was cloned as:

git clone git://sourceware.org/git/glibc.git
cd glibc
git checkout glibc-2.28

Setup 2: test it out

Once you have built he toolchain that you want, test it out with:

#!/usr/bin/env bash
set -eux
install_dir="${CT_PREFIX}/x86_64-unknown-linux-gnu"
PATH="${PATH}:${install_dir}/bin" \
  x86_64-unknown-linux-gnu-gcc \
  -Wl,--dynamic-linker="${install_dir}/x86_64-unknown-linux-gnu/sysroot/lib/ld-linux-x86-64.so.2" \
  -Wl,--rpath="${install_dir}/x86_64-unknown-linux-gnu/sysroot/lib" \
  -v \
  -o test_glibc.out \
  test_glibc.c \
  -pthread \
;
ldd test_glibc.out
./test_glibc.out

Everything seems to work as in Setup 1, except that now the correct runtime objects were used:

COLLECT_GCC_OPTIONS=/home/ciro/crosstool-ng/.build/install/x86_64-unknown-linux-gnu/bin/../x86_64-unknown-linux-gnu/sysroot/usr/lib/../lib64/crt1.o

Setup 2: failed efficient glibc recompilation attempt

It does not seem possible with crosstool-NG, as explained below.

If you just re-build;

env -u LD_LIBRARY_PATH time ./ct-ng build CT_JOBS=`nproc`

then your changes to the custom glibc source location are taken into account, but it builds everything from scratch, making it unusable for iterative development.

If we do:

./ct-ng list-steps

it gives a nice overview of the build steps:

Available build steps, in order:
  - companion_tools_for_build
  - companion_libs_for_build
  - binutils_for_build
  - companion_tools_for_host
  - companion_libs_for_host
  - binutils_for_host
  - cc_core_pass_1
  - kernel_headers
  - libc_start_files
  - cc_core_pass_2
  - libc
  - cc_for_build
  - cc_for_host
  - libc_post_cc
  - companion_libs_for_target
  - binutils_for_target
  - debug
  - test_suite
  - finish
Use "<step>" as action to execute only that step.
Use "+<step>" as action to execute up to that step.
Use "<step>+" as action to execute from that step onward.

therefore, we see that there are glibc steps intertwined with several GCC steps, most notably libc_start_files comes before cc_core_pass_2, which is likely the most expensive step together with cc_core_pass_1.

In order to build just one step, you must first set the "Save intermediate steps" in .config option for the intial build:

  • Paths and misc options
    • Debug crosstool-NG
      • Save intermediate steps

and then you can try:

env -u LD_LIBRARY_PATH time ./ct-ng libc+ -j`nproc`

but unfortunately, the + required as mentioned at: https://github.com/crosstool-ng/crosstool-ng/issues/1033#issuecomment-424877536

Note however that restarting at an intermediate step resets the installation directory to the state it had during that step. I.e., you will have a rebuilt libc - but no final compiler built with this libc (and hence, no compiler libraries like libstdc++ either).

and basically still makes the rebuild too slow to be feasible for development, and I don't see how to overcome this without patching crosstool-NG.

Furthermore, starting from the libc step didn't seem to copy over the source again from Custom source location, further making this method unusable.

Bonus: stdlibc++

A bonus if you're also interested in the C++ standard library: How to edit and re-build the GCC libstdc++ C++ standard library source?

Get parent directory of running script

Fugly, but this will do it:

substr($_SERVER['SCRIPT_NAME'], 0, strpos($_SERVER['SCRIPT_NAME'],basename($_SERVER['SCRIPT_NAME'])))

How to enable scrolling of content inside a modal?

In Bootstrap 3 you have to change the css class .modal

before (bootstrap default) :

.modal {

    overflow-y: auto;
}

after (after you edit it):

.modal {

    overflow-y: scroll;
}

How do I prevent Eclipse from hanging on startup?

What worked for me was this-- On Ubuntu

  1. Ctrl+F1
  2. ps -e
  3. kill -9 for process ids of eclipse, java and adb

Function for Factorial in Python

def factorial(n):
    if n < 2:
        return 1
    return n * factorial(n - 1)

jQuery select2 get value of select tag?

$("#first").select2('data') will return all data as map

How can I remove an SSH key?

I can confirm that this bug is still present in Ubuntu 19.04 (Disco Dingo). The workaround suggested by VonC worked perfectly, summarizing for my version:

  • Click on Activities tab on top left corner
  • On the search box that comes up, begin typing "startup applications"
  • Click on the "Startup Applications" icon
  • On the box that pops up, select the gnome key ring manager application (can't remember the exact name on the GUI but it is distinctive enough) and remove it.

Next, I tried ssh-add -D again, and after reboot ssh-add -l told me The agent has no identities. I confirmed that I still had the ssh-agent daemon running with ps aux | grep agent. So I added the key I most frequently used with GitHub (ssh-add ~/.ssh/id_ecdsa) and all was good!

Now I can do the normal operations with my most frequently used repository, and if I occasionally require access to the other repository which uses the RSA key, I just dedicate one terminal for it with export GIT_SSH_COMMAND="ssh -i /home/me/.ssh/id_rsa.pub". Solved! Credit goes to VonC for pointing out the bug and the solution.

How to Copy Contents of One Canvas to Another Canvas Locally

@robert-hurst has a cleaner approach.

However, this solution may also be used, in places when you actually want to have a copy of Data Url after copying. For example, when you are building a website that uses lots of image/canvas operations.

    // select canvas elements
    var sourceCanvas = document.getElementById("some-unique-id");
    var destCanvas = document.getElementsByClassName("some-class-selector")[0];

    //copy canvas by DataUrl
    var sourceImageData = sourceCanvas.toDataURL("image/png");
    var destCanvasContext = destCanvas.getContext('2d');

    var destinationImage = new Image;
    destinationImage.onload = function(){
      destCanvasContext.drawImage(destinationImage,0,0);
    };
    destinationImage.src = sourceImageData;

Move textfield when keyboard appears swift

I modified @Simpa solution a little bit.........

override func viewDidLoad() 
{

    super.viewDidLoad()
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("makeSpaceForKeyboard:"), name:UIKeyboardWillShowNotification, object: nil);
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("makeSpaceForKeyboard:"), name:UIKeyboardWillHideNotification, object: nil);
}

deinit{
    NSNotificationCenter.defaultCenter().removeObserver(self)
}

var keyboardIsVisible = false
override func makeSpaceForKeyboard(notification: NSNotification) {

    let info = notification.userInfo!
    let keyboardHeight:CGFloat = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue().size.height
    let duration:Double = info[UIKeyboardAnimationDurationUserInfoKey] as! Double

    if notification.name == UIKeyboardWillShowNotification && keyboardIsVisible == false{

        keyboardIsVisible = true

        UIView.animateWithDuration(duration, animations: { () -> Void in
            var frame = self.view.frame
            frame.size.height = frame.size.height - keyboardHeight
            self.view.frame = frame
        })

    } else if keyboardIsVisible == true && notification.name == UIKeyboardWillShowNotification{

    }else {
        keyboardIsVisible = false

        UIView.animateWithDuration(duration, animations: { () -> Void in
            var frame = self.view.frame
            frame.size.height = frame.size.height + keyboardHeight
            self.view.frame = frame
        })
    }
}

Split data frame string column into multiple columns

Here is a base R one liner that overlaps a number of previous solutions, but returns a data.frame with the proper names.

out <- setNames(data.frame(before$attr,
                  do.call(rbind, strsplit(as.character(before$type),
                                          split="_and_"))),
                  c("attr", paste0("type_", 1:2)))
out
  attr type_1 type_2
1    1    foo    bar
2   30    foo  bar_2
3    4    foo    bar
4    6    foo  bar_2

It uses strsplit to break up the variable, and data.frame with do.call/rbind to put the data back into a data.frame. The additional incremental improvement is the use of setNames to add variable names to the data.frame.

Count words in a string method?

    String a = "Some String";
    int count = 0;
    for (int i = 0; i < a.length(); i++) {

        if (Character.isWhitespace(a.charAt(i))) {
            count++; 
        }
    }
    System.out.println(count+1);

It will count white spaces. However, If we add 1 in count , we can get exact words.

Create an enum with string values

TypeScript 2.1 +

Lookup types, introduced in TypeScript 2.1 allow another pattern for simulating string enums:

// String enums in TypeScript 2.1
const EntityType = {
    Foo: 'Foo' as 'Foo',
    Bar: 'Bar' as 'Bar'
};

function doIt(entity: keyof typeof EntityType) {
    // ...
}

EntityType.Foo          // 'Foo'
doIt(EntityType.Foo);   // 
doIt(EntityType.Bar);   // 
doIt('Foo');            // 
doIt('Bad');            //  

TypeScript 2.4 +

With version 2.4, TypeScript introduced native support for string enums, so the solution above is not needed. From the TS docs:

enum Colors {
  Red = "RED",
  Green = "GREEN",
  Blue = "BLUE",
}

Trying to get PyCharm to work, keep getting "No Python interpreter selected"

Go to File->Settings->Project Settings->Project Interpreter->Python Interpreters

There will be a "+" sign on the right side. Navigate to your python binary, PyCharm will figure out the rest.

How do I attach events to dynamic HTML elements with jQuery?

If you're adding a pile of anchors to the DOM, look into event delegation instead.

Here's a simple example:

$('#somecontainer').click(function(e) {   
  var $target = $(e.target);   
  if ($target.hasClass("myclass")) {
    // do something
  }
});

HTML Tags in Javascript Alert() method

alert() is a method of the window object that cannot interpret HTML tags

Is it possible to send an array with the Postman Chrome extension?

{
    "data" : [  
        {
            "key1" : "value1",
            "key2" : "value2"   
        },
        {
            "key01" : "value01",
            "key02" : "value02"             
        },
        {
            "key10" : "value10",
            "key20" : "value20"   
        }
    ]
}

You can pass like this. Hope this will help someone.

Replace special characters in a string with _ (underscore)

string = string.replace(/[&\/\\#,+()$~%.'":*?<>{}]/g,'_');

Alternatively, to change all characters except numbers and letters, try:

string = string.replace(/[^a-zA-Z0-9]/g,'_');

Using wire or reg with input or output in Verilog

An output reg foo is just shorthand for output foo_wire; reg foo; assign foo_wire = foo. It's handy when you plan to register that output anyway. I don't think input reg is meaningful for module (perhaps task). input wire and output wire are the same as input and output: it's just more explicit.

How to run functions in parallel?

You could use threading or multiprocessing.

Due to peculiarities of CPython, threading is unlikely to achieve true parallelism. For this reason, multiprocessing is generally a better bet.

Here is a complete example:

from multiprocessing import Process

def func1():
  print 'func1: starting'
  for i in xrange(10000000): pass
  print 'func1: finishing'

def func2():
  print 'func2: starting'
  for i in xrange(10000000): pass
  print 'func2: finishing'

if __name__ == '__main__':
  p1 = Process(target=func1)
  p1.start()
  p2 = Process(target=func2)
  p2.start()
  p1.join()
  p2.join()

The mechanics of starting/joining child processes can easily be encapsulated into a function along the lines of your runBothFunc:

def runInParallel(*fns):
  proc = []
  for fn in fns:
    p = Process(target=fn)
    p.start()
    proc.append(p)
  for p in proc:
    p.join()

runInParallel(func1, func2)

Android Activity as a dialog

Some times you can get the Exception which is given below

Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

So for resolving you can use simple solution

add theme of you activity in manifest as dialog for appCompact.

android:theme="@style/Theme.AppCompat.Dialog"

It can be helpful for somebody.

Redirect from an HTML page

Put the following code in the <head> section:

<meta http-equiv="refresh" content="0; url=http://address/">

How to retrieve field names from temporary table (SQL Server 2008)

To use information_schema and not collide with other sessions:

select * 
from tempdb.INFORMATION_SCHEMA.COLUMNS
where table_name =
    object_name(
        object_id('tempdb..#test'),
        (select database_id from sys.databases where name = 'tempdb'))

ERROR: permission denied for relation tablename on Postgres while trying a SELECT as a readonly user

Here is the complete solution for PostgreSQL 9+, updated recently.

CREATE USER readonly  WITH ENCRYPTED PASSWORD 'readonly';
GRANT USAGE ON SCHEMA public to readonly;
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO readonly;

-- repeat code below for each database:

GRANT CONNECT ON DATABASE foo to readonly;
\c foo
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO readonly; --- this grants privileges on new tables generated in new database "foo"
GRANT USAGE ON SCHEMA public to readonly; 
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO readonly;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO readonly;

Thanks to https://jamie.curle.io/creating-a-read-only-user-in-postgres/ for several important aspects

If anyone find shorter code, and preferably one that is able to perform this for all existing databases, extra kudos.

Where does npm install packages?

If you are looking for the executable that npm installed, maybe because you would like to put it in your PATH, you can simply do

npm bin

or

npm bin -g

UICollectionView - dynamic cell height?

I just ran into this problem on a UICollectionView and the way that i solved it similar to the answer above but in a pure UICollectionView way.

  1. Create a custom UICollectionViewCell that contains whatever you will be filling it with to make it dynamic. I created its own .xib for it as it seems like the easiest approach.

  2. Add constraints in that .xib that allow for the cell to be calculated from top to bottom. The re-sizing won't work if you haven't accounted for all of the height. Say you have a view on top, then a label underneath it, and another label underneath that. You would need to connect constraints to the top of the cell to the top of that view, then the bottom of the view to the top of the first label, bottom of first label to the top of the second label, and bottom of second label to bottom of cell.

  3. Load the .xib into the viewcontroller and register it with the collectionView on viewDidLoad

    let nib = UINib(nibName: CustomCellName, bundle: nil)
    self.collectionView!.registerNib(nib, forCellWithReuseIdentifier: "customCellID")`
    
  4. Load a second copy of that xib into the class and store it as a property so you can use it to determine the size of what that cell should be

    let sizingNibNew = NSBundle.mainBundle().loadNibNamed(CustomCellName, owner: CustomCellName.self, options: nil) as NSArray
    self.sizingNibNew = (sizingNibNew.objectAtIndex(0) as? CustomViewCell)!
    
  5. Implement the UICollectionViewFlowLayoutDelegate in your view controller. The method that matters is called sizeForItemAtIndexPath. Inside that method you will need to pull the data from the datasource that is associated with that cell from the indexPath. Then configure the sizingCell and call preferredLayoutSizeFittingSize. The method returns a CGSize which will consist of the width minus the content insets and the height that is returned from self.sizingCell.preferredLayoutSizeFittingSize(targetSize).

    override func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
        guard let data = datasourceArray?[indexPath.item] else {
            return CGSizeZero
        }
        let sectionInset = self.collectionView?.collectionViewLayout.sectionInset
        let widthToSubtract = sectionInset!.left + sectionInset!.right
    
        let requiredWidth = collectionView.bounds.size.width
    
    
        let targetSize = CGSize(width: requiredWidth, height: 0)
    
        sizingNibNew.configureCell(data as! CustomCellData, delegate: self)
        let adequateSize = self.sizingNibNew.preferredLayoutSizeFittingSize(targetSize)
        return CGSize(width: (self.collectionView?.bounds.width)! - widthToSubtract, height: adequateSize.height)
     }
    
  6. In the class of the custom cell itself you will need to override awakeFromNib and tell the contentView that its size needs to be flexible

     override func awakeFromNib() {
        super.awakeFromNib()
        self.contentView.autoresizingMask = [UIViewAutoresizing.FlexibleHeight]
     }
    
  7. In the custom cell override layoutSubviews

     override func layoutSubviews() {
       self.layoutIfNeeded()
      }
    
  8. In the class of the custom cell implement preferredLayoutSizeFittingSize. This is where you will need to do any trickery on the items that are being laid out. If its a label you will need to tell it what its preferredMaxWidth should be.

    func preferredLayoutSizeFittingSize(_ targetSize: CGSize)-> CGSize {
    
        let originalFrame = self.frame
        let originalPreferredMaxLayoutWidth = self.label.preferredMaxLayoutWidth
    
    
        var frame = self.frame
        frame.size = targetSize
        self.frame = frame
    
        self.setNeedsLayout()
        self.layoutIfNeeded()
        self.label.preferredMaxLayoutWidth = self.questionLabel.bounds.size.width
    
    
        // calling this tells the cell to figure out a size for it based on the current items set
        let computedSize = self.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize)
    
        let newSize = CGSize(width:targetSize.width, height:computedSize.height)
    
        self.frame = originalFrame
        self.questionLabel.preferredMaxLayoutWidth = originalPreferredMaxLayoutWidth
    
        return newSize
    }
    

All those steps should give you the correct sizes. If your getting 0 or other funky numbers than you haven't set up your constraints properly.

SSL handshake alert: unrecognized_name error since upgrade to Java 1.7.0

Java 7 introduced SNI support which is enabled by default. I have found out that certain misconfigured servers send an "Unrecognized Name" warning in the SSL handshake which is ignored by most clients... except for Java. As @Bob Kerns mentioned, the Oracle engineers refuse to "fix" this bug/feature.

As workaround, they suggest to set the jsse.enableSNIExtension property. To allow your programs to work without re-compiling, run your app as:

java -Djsse.enableSNIExtension=false yourClass

The property can also be set in the Java code, but it must be set before any SSL actions. Once the SSL library has loaded, you can change the property, but it won't have any effect on the SNI status. To disable SNI on runtime (with the aforementioned limitations), use:

System.setProperty("jsse.enableSNIExtension", "false");

The disadvantage of setting this flag is that SNI is disabled everywhere in the application. In order to make use of SNI and still support misconfigured servers:

  1. Create a SSLSocket with the host name you want to connect to. Let's name this sslsock.
  2. Try to run sslsock.startHandshake(). This will block until it is done or throw an exception on error. Whenever an error occurred in startHandshake(), get the exception message. If it equals to handshake alert: unrecognized_name, then you have found a misconfigured server.
  3. When you have received the unrecognized_name warning (fatal in Java), retry opening a SSLSocket, but this time without a host name. This effectively disables SNI (after all, the SNI extension is about adding a host name to the ClientHello message).

For the Webscarab SSL proxy, this commit implements the fall-back setup.

Returning multiple objects in an R function

You could use for() with assign() to create many objects. See the example from assign():

for(i in 1:6) { #-- Create objects  'r.1', 'r.2', ... 'r.6' --
    nam <- paste("r", i, sep = ".")
    assign(nam, 1:i)

Looking the new objects

ls(pattern = "^r..$")

Entity framework code-first null foreign key

I recommend to read Microsoft guide for use Relationships, Navigation Properties and Foreign Keys in EF Code First, like this picture.

enter image description here

Guide link below:

https://docs.microsoft.com/en-gb/ef/ef6/fundamentals/relationships?redirectedfrom=MSDN

Check if String / Record exists in DataTable

I think that if your "item_manuf_id" is the primary key of the DataTable you could use the Find method ...

string s = "stringValue";
DataRow foundRow = dtPs.Rows.Find(s);
if(foundRow != null) {
 //You have it ...
 }

How to add/update child entities when updating a parent entity in EF

Just proof of concept Controler.UpdateModel won't work correctly.

Full class here:

const string PK = "Id";
protected Models.Entities con;
protected System.Data.Entity.DbSet<T> model;

private void TestUpdate(object item)
{
    var props = item.GetType().GetProperties();
    foreach (var prop in props)
    {
        object value = prop.GetValue(item);
        if (prop.PropertyType.IsInterface && value != null)
        {
            foreach (var iItem in (System.Collections.IEnumerable)value)
            {
                TestUpdate(iItem);
            }
        }
    }

    int id = (int)item.GetType().GetProperty(PK).GetValue(item);
    if (id == 0)
    {
        con.Entry(item).State = System.Data.Entity.EntityState.Added;
    }
    else
    {
        con.Entry(item).State = System.Data.Entity.EntityState.Modified;
    }

}

What's the environment variable for the path to the desktop?

This should work no matter what language version of Windows it is and no matter where the folder is located. It also doesn't matter whether there are any spaces in the folder path.

FOR /F "tokens=2*" %%A IN ('REG QUERY "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders" /v Desktop^|FIND/I "desktop"') DO SET Desktop=%%B
ECHO %Desktop%

In case of Windows 2000 (and probably NT 4.0) you need to copy reg.exe to the %windir% folder manually since it is not available there by default.

how to check if input field is empty

if you are using jquery-validate.js in your application then use below expression.

if($("#spa").is(":blank"))
{
  //code
}

What's the difference between ngOnInit and ngAfterViewInit of Angular2?

Content is what is passed as children. View is the template of the current component.

The view is initialized before the content and ngAfterViewInit() is therefore called before ngAfterContentInit().

** ngAfterViewInit() is called when the bindings of the children directives (or components) have been checked for the first time. Hence its perfect for accessing and manipulating DOM with Angular 2 components. As @Günter Zöchbauer mentioned before is correct @ViewChild() hence runs fine inside it.

Example:

@Component({
    selector: 'widget-three',
    template: `<input #input1 type="text">`
})
export class WidgetThree{
    @ViewChild('input1') input1;

    constructor(private renderer:Renderer){}

    ngAfterViewInit(){
        this.renderer.invokeElementMethod(
            this.input1.nativeElement,
            'focus',
            []
        )
    }
}

use video as background for div

I believe this is what you're looking for. It automatically scaled the video to fit the container.

DEMO: http://jsfiddle.net/t8qhgxuy/

Video need to have height and width always set to 100% of the parent.

HTML:

<div class="one"> CONTENT OVER VIDEO
    <video class="video-background" no-controls autoplay src="https://dl.dropboxusercontent.com/u/8974822/cloud-troopers-video.mp4" poster="http://thumb.multicastmedia.com/thumbs/aid/w/h/t1351705158/1571585.jpg"></video>
</div>

<div class="two">
    <video class="video-background" no-controls autoplay src="https://dl.dropboxusercontent.com/u/8974822/cloud-troopers-video.mp4" poster="http://thumb.multicastmedia.com/thumbs/aid/w/h/t1351705158/1571585.jpg"></video> CONTENT OVER VIDEO
</div>

CSS:

body {
    overflow: scroll;
    padding:  60px 20px;
}

.one {
    width: 90%;
    height: 30vw;
    overflow: hidden;
    border: 15px solid red;
    margin-bottom: 40px;
    position: relative;
}

.two{
    width: 30%;
    height: 300px;
    overflow: hidden;
    border: 15px solid blue;
    position: relative;
}

.video-background { /* class name used in javascript too */
    width: 100%; /* width needs to be set to 100% */
    height: 100%; /* height needs to be set to 100% */
    position: absolute;
    left: 0;
    top: 0;
    z-index: -1;
}

JS:

function scaleToFill() {
    $('video.video-background').each(function(index, videoTag) {
       var $video = $(videoTag),
           videoRatio = videoTag.videoWidth / videoTag.videoHeight,
           tagRatio = $video.width() / $video.height(),
           val;

       if (videoRatio < tagRatio) {
           val = tagRatio / videoRatio * 1.02; <!-- size increased by 2% because value is not fine enough and sometimes leaves a couple of white pixels at the edges -->
       } else if (tagRatio < videoRatio) {
           val = videoRatio / tagRatio * 1.02;
       }

       $video.css('transform','scale(' + val  + ',' + val + ')');

    });    
}

$(function () {
    scaleToFill();

    $('.video-background').on('loadeddata', scaleToFill);

    $(window).resize(function() {
        scaleToFill();
    });
});

Remove non-ascii character in string

None of these answers properly handle tabs, newlines, carriage returns, and some don't handle extended ASCII and unicode. This will KEEP tabs & newlines, but remove control characters and anything out of the ASCII set. Click "Run this code snippet" button to test. There is some new javascript coming down the pipe so in the future (2020+?) you may have to do \u{FFFFF} but not yet

_x000D_
_x000D_
console.log("line 1\nline2 \n\ttabbed\nF??^?¯?^??????????????l????~¨??????_??????a?????"????????????v?¯?????i????o?????????????????????".replace(/[\x00-\x08\x0E-\x1F\x7F-\uFFFF]/g, ''))
_x000D_
_x000D_
_x000D_

Pandas unstack problems: ValueError: Index contains duplicate entries, cannot reshape

There's a far more simpler solution to tackle this.

The reason why you get ValueError: Index contains duplicate entries, cannot reshape is because, once you unstack "Location", then the remaining index columns "id" and "date" combinations are no longer unique.

You can avoid this by retaining the default index column (row #) and while setting the index using "id", "date" and "location", add it in "append" mode instead of the default overwrite mode.

So use,

e.set_index(['id', 'date', 'location'], append=True)

Once this is done, your index columns will still have the default index along with the set indexes. And unstack will work.

Let me know how it works out.

difference between variables inside and outside of __init__()

This is very easy to understand if you track class and instance dictionaries.

class C:
   one = 42
   def __init__(self,val):
        self.two=val
ci=C(50)
print(ci.__dict__)
print(C.__dict__)

The result will be like this:

{'two': 50}
{'__module__': '__main__', 'one': 42, '__init__': <function C.__init__ at 0x00000213069BF6A8>, '__dict__': <attribute '__dict__' of 'C' objects>, '__weakref__': <attribute '__weakref__' of 'C' objects>, '__doc__': None}

Note I set the full results in here but what is important that the instance ci dict will be just {'two': 50}, and class dictionary will have the 'one': 42 key value pair inside.

This is all you should know about that specific variables.

How to Navigate from one View Controller to another using Swift

Swift 5

Use Segue to perform navigation from one View Controller to another View Controller:

performSegue(withIdentifier: "idView", sender: self)

This works on Xcode 10.2.

Simulate string split function in Excel formula

=IFERROR(LEFT(A3, FIND(" ", A3, 1)), A3)

This will firstly check if the cell contains a space, if it does it will return the first value from the space, otherwise it will return the cell value.

Edit

Just to add to the above formula, as it stands if there is no value in the cell it would return 0. If you are looking to display a message or something to tell the user it is empty you could use the following:

=IF(IFERROR(LEFT(A3, FIND(" ", A3, 1)), A3)=0, "Empty", IFERROR(LEFT(A3, FIND(" ", A3, 1)), A3))

Producer/Consumer threads using a Queue

Use this typesafe pattern with poison pills:

public sealed interface BaseMessage {

    final class ValidMessage<T> implements BaseMessage {

        @Nonnull
        private final T value;


        public ValidMessage(@Nonnull T value) {
            this.value = value;
        }

        @Nonnull
        public T getValue() {
            return value;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            ValidMessage<?> that = (ValidMessage<?>) o;
            return value.equals(that.value);
        }

        @Override
        public int hashCode() {
            return Objects.hash(value);
        }

        @Override
        public String toString() {
            return "ValidMessage{value=%s}".formatted(value);
        }
    }

    final class PoisonedMessage implements BaseMessage {

        public static final PoisonedMessage INSTANCE = new PoisonedMessage();


        private PoisonedMessage() {
        }

        @Override
        public String toString() {
            return "PoisonedMessage{}";
        }
    }
}

public class Producer implements Callable<Void> {

    @Nonnull
    private final BlockingQueue<BaseMessage> messages;

    Producer(@Nonnull BlockingQueue<BaseMessage> messages) {
        this.messages = messages;
    }

    @Override
    public Void call() throws Exception {
        messages.put(new BaseMessage.ValidMessage<>(1));
        messages.put(new BaseMessage.ValidMessage<>(2));
        messages.put(new BaseMessage.ValidMessage<>(3));
        messages.put(BaseMessage.PoisonedMessage.INSTANCE);
        return null;
    }
}

public class Consumer implements Callable<Void> {

    @Nonnull
    private final BlockingQueue<BaseMessage> messages;

    private final int maxPoisons;


    public Consumer(@Nonnull BlockingQueue<BaseMessage> messages, int maxPoisons) {
        this.messages = messages;
        this.maxPoisons = maxPoisons;
    }

    @Override
    public Void call() throws Exception {
        int poisonsReceived = 0;
        while (poisonsReceived < maxPoisons && !Thread.currentThread().isInterrupted()) {
            BaseMessage message = messages.take();
            if (message instanceof BaseMessage.ValidMessage<?> vm) {
                Integer value = (Integer) vm.getValue();
                System.out.println(value);
            } else if (message instanceof BaseMessage.PoisonedMessage) {
                ++poisonsReceived;
            } else {
                throw new IllegalArgumentException("Invalid BaseMessage type: " + message);
            }
        }
        return null;
    }
}

How to check encoding of a CSV file

In Linux systems, you can use file command. It will give the correct encoding

Sample:

file blah.csv

Output:

blah.csv: ISO-8859 text, with very long lines

Unit testing private methods in C#

One way to test private methods is through reflection. This applies to NUnit and XUnit, too:

MyObject objUnderTest = new MyObject();
MethodInfo methodInfo = typeof(MyObject).GetMethod("SomePrivateMethod", BindingFlags.NonPublic | BindingFlags.Instance);
object[] parameters = {"parameters here"};
methodInfo.Invoke(objUnderTest, parameters);

No mapping found for HTTP request with URI.... in DispatcherServlet with name

If you want to serve .html files, you must add this <mvc:default-servlet-handler /> in your spring config file. .html files are static. Hope that this can help someone.

In Excel, how do I extract last four letters of a ten letter string?

No need to use a macro. Supposing your first string is in A1.

=RIGHT(A1, 4)

Drag this down and you will get your four last characters.

Edit: To be sure, if you ever have sequences like 'ABC DEF' and want the last four LETTERS and not CHARACTERS you might want to use trimspaces()

=RIGHT(TRIMSPACES(A1), 4)

Edit: As per brettdj's suggestion, you may want to check that your string is actually 4-character long or more:

=IF(TRIMSPACES(A1)>=4, RIGHT(TRIMSPACES(A1), 4), TRIMSPACES(A1))

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

You are not specified your project as right way.

  • So run your XAMPP control panel then start the apache and MySQL
  • Then note the ports.
  • For Example PORT 80: then you type your browser url as localhost:80\ press enter now your php basic Config page is visible.
  • Then create any folder on xampp\htdocs\YourFloderName Then create php file then save it and go to browser then type it localhost\YourFolderName now it listed the files click the file and it runs.

How do you Hover in ReactJS? - onMouseLeave not registered during fast hover over

The previous answers are pretty confusing. You don't need a react-state to solve this, nor any special external lib. It can be achieved with pure css/sass:

The style:

.hover {
  position: relative;

  &:hover &__no-hover {
    opacity: 0;
  }

  &:hover &__hover {
    opacity: 1;
  }

  &__hover {
    position: absolute;
    top: 0;
    opacity: 0;
  }

  &__no-hover {
    opacity: 1;
  }
}

The React-Component

A simple Hover Pure-Rendering-Function:

const Hover = ({ onHover, children }) => (
    <div className="hover">
        <div className="hover__no-hover">{children}</div>
        <div className="hover__hover">{onHover}</div>
    </div>
)

Usage

Then use it like this:

    <Hover onHover={<div> Show this on hover </div>}>
        <div> Show on no hover </div>
    </Hover>

What is middleware exactly?

There is a common definition in web application development which is (and I'm making this wording up but it seems to fit): A component which is designed to modify an HTTP request and/or response but does not (usually) serve the response in its entirety, designed to be chained together to form a pipeline of behavioral changes during request processing.

Examples of tasks that are commonly implemented by middleware:

  • Gzip response compression
  • HTTP authentication
  • Request logging

The key point here is that none of these is fully responsible for responding to the client. Instead each changes the behavior in some way as part of the pipeline, leaving the actual response to come from something later in the sequence (pipeline).

Usually, the middlewares are run before some sort of "router", which examines the request (often the path) and calls the appropriate code to generate the response.

Personally, I hate the term "middleware" for its genericity but it is in common use.

Here is an additional explanation specifically applicable to Ruby on Rails.

HTML image bottom alignment inside DIV container

Set the parent div as position:relative and the inner element to position:absolute; bottom:0

MySQL - How to increase varchar size of an existing column in a database without breaking existing data?

For me worked this one:

ALTER TABLE tablename MODIFY fieldname VARCHAR(128) NOT NULL;

Converting array to list in Java

One-liner:

List<Integer> list = Arrays.asList(new Integer[] {1, 2, 3, 4});

How to add a default include path for GCC in Linux?

A gcc spec file can do the job, however all users on the machine will be affected.

See here

Specify system property to Maven project

If your test and webapp are in the same Maven project, you can use a property in the project POM. Then you can filter certain files which will allow Maven to set the property in those files. There are different ways to filter, but the most common is during the resources phase - http://books.sonatype.com/mvnref-book/reference/resource-filtering-sect-description.html

If the test and webapp are in different Maven projects, you can put the property in settings.xml, which is in your maven repository folder (C:\Documents and Settings\username.m2) on Windows. You will still need to use filtering or some other method to read the property into your test and webapp.

Replacing instances of a character in a string

You cannot simply assign value to a character in the string. Use this method to replace value of a particular character:

name = "India"
result=name .replace("d",'*')

Output: In*ia

Also, if you want to replace say * for all the occurrences of the first character except the first character, eg. string = babble output = ba**le

Code:

name = "babble"
front= name [0:1]
fromSecondCharacter = name [1:]
back=fromSecondCharacter.replace(front,'*')
return front+back

How, in general, does Node.js handle 10,000 concurrent requests?

Adding to slebetman answer: When you say Node.JS can handle 10,000 concurrent requests they are essentially non-blocking requests i.e. these requests are majorly pertaining to database query.

Internally, event loop of Node.JS is handling a thread pool, where each thread handles a non-blocking request and event loop continues to listen to more request after delegating work to one of the thread of the thread pool. When one of the thread completes the work, it send a signal to the event loop that it has finished aka callback. Event loop then process this callback and send the response back.

As you are new to NodeJS, do read more about nextTick to understand how event loop works internally. Read blogs on http://javascriptissexy.com, they were really helpful for me when I started with JavaScript/NodeJS.

How to compare two dates in php

Don't know what your problem is but:

function date_compare($d1, $d2)
{
    $d1 = explode('_', $d1);
    $d2 = explode('_', $d2);
    
    $d1 = array_reverse($d1);
    $d2 = array_reverse($d2);
    
    if (strtotime(implode('-', $d1)) > strtotime(implode('-', $d2)))
    {
        return $d2;
    }
    else
    {
        return $d1;
    }
}

JS Client-Side Exif Orientation: Rotate and Mirror JPEG Images

I am using mixed solution (php+css).

Containers are needed for:

  • div.imgCont2 container needed to rotate;
  • div.imgCont1 container needed to zoomOut - width:150%;
  • div.imgCont container needed for scrollbars, when image is zoomOut.

.

<?php
    $image_url = 'your image url.jpg';
    $exif = @exif_read_data($image_url,0,true);
    $orientation = @$exif['IFD0']['Orientation'];
?>

<style>
.imgCont{
    width:100%;
    overflow:auto;
}
.imgCont2[data-orientation="8"]{
    transform:rotate(270deg);
    margin:15% 0;
}
.imgCont2[data-orientation="6"]{
    transform:rotate(90deg);
    margin:15% 0;
}
.imgCont2[data-orientation="3"]{
    transform:rotate(180deg);
}
img{
    width:100%;
}
</style>

<div class="imgCont">
  <div class="imgCont1">
    <div class="imgCont2" data-orientation="<?php echo($orientation) ?>">
      <img src="<?php echo($image_url) ?>">
    </div>
  </div>
</div>

What throws an IOException in Java?

Assume you were:

  1. Reading a network file and got disconnected.
  2. Reading a local file that was no longer available.
  3. Using some stream to read data and some other process closed the stream.
  4. Trying to read/write a file, but don't have permission.
  5. Trying to write to a file, but disk space was no longer available.

There are many more examples, but these are the most common, in my experience.

Indentation shortcuts in Visual Studio

Just hit Tab to push it over or on the menu bar Edit --> Advanced --> Format Selection and that will auto indent, the keyboard shortcut is also shown in the menu.

Sys is undefined

Make sure that any client scripts you have that interact with .NET AJAX have the following line at the end:

if (typeof(Sys) !== 'undefined')  Sys.Application.notifyScriptLoaded();

This tells the script manager that the whole script file has loaded and that it can begin to call client methods

What does "Object reference not set to an instance of an object" mean?

Not to be blunt but it means exactly what it says. One of your object references is NULL. You'll see this when you try and access the property or method of a NULL'd object.

Merge r brings error "'by' must specify uniquely valid columns"

Rather give names of the column on which you want to merge:

exporttab <- merge(x=dwd_nogap, y=dwd_gap, by.x='x1', by.y='x2', fill=-9999)

How to push objects in AngularJS between ngRepeat arrays

You'd be much better off using the same array with both lists, and creating angular filters to achieve your goal.

http://docs.angularjs.org/guide/dev_guide.templates.filters.creating_filters

Rough, untested code follows:

appModule.filter('checked', function() {
    return function(input, checked) {
        if(!input)return input;
        var output = []
        for (i in input){
            var item = input[i];
            if(item.checked == checked)output.push(item);
        }
        return output
    }
});

and the view (i added an "uncheck" button too)

<div id="AddItem">
     <h3>Add Item</h3>

    <input value="1" type="number" placeholder="1" ng-model="itemAmount">
    <input value="" type="text" placeholder="Name of Item" ng-model="itemName">
    <br/>
    <button ng-click="addItem()">Add to list</button>
</div>
<!-- begin: LIST OF CHECKED ITEMS -->
<div id="CheckedList">
     <h3>Checked Items: {{getTotalCheckedItems()}}</h3>

     <h4>Checked:</h4>

    <table>
        <tr ng-repeat="item in items | checked:true" class="item-checked">
            <td><b>amount:</b> {{item.amount}} -</td>
            <td><b>name:</b> {{item.name}} -</td>
            <td> 
               <i>this item is checked!</i>
               <button ng-click="item.checked = false">uncheck item</button>

            </td>
        </tr>
    </table>
</div>
<!-- end: LIST OF CHECKED ITEMS -->
<!-- begin: LIST OF UNCHECKED ITEMS -->
<div id="UncheckedList">
     <h3>Unchecked Items: {{getTotalItems()}}</h3>

     <h4>Unchecked:</h4>

    <table>
        <tr ng-repeat="item in items | checked:false" class="item-unchecked">
            <td><b>amount:</b> {{item.amount}} -</td>
            <td><b>name:</b> {{item.name}} -</td>
            <td>
                <button ng-click="item.checked = true">check item</button>
            </td>
        </tr>
    </table>
</div>
<!-- end: LIST OF ITEMS -->

Then you dont need the toggle methods etc in your controller

Do AJAX requests retain PHP Session info?

The answer is yes:

Sessions are maintained server-side. As far as the server is concerned, there is no difference between an AJAX request and a regular page request. They are both HTTP requests, and they both contain cookie information in the header in the same way.

From the client side, the same cookies will always be sent to the server whether it's a regular request or an AJAX request. The Javascript code does not need to do anything special or even to be aware of this happening, it just works the same as it does with regular requests.

How to filter an array/object by checking multiple values

You can use .filter() with boolean operators ie &&:

     var find = my_array.filter(function(result) {
       return result.param1 === "srting1" && result.param2 === 'string2';
     });
     
     return find[0];

I want to calculate the distance between two points in Java

Based on the @trashgod's comment, this is the simpliest way to calculate distance:

double distance = Math.hypot(x1-x2, y1-y2);

From documentation of Math.hypot:

Returns: sqrt(x²+ y²) without intermediate overflow or underflow.

How to split a python string on new line characters

a.txt

this is line 1
this is line 2

code:

Python 3.4.0 (default, Mar 20 2014, 22:43:40) 
[GCC 4.6.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> file = open('a.txt').read()
>>> file
>>> file.split('\n')
['this is line 1', 'this is line 2', '']

I'm on Linux, but I guess you just use \r\n on Windows and it would also work

Create an empty data.frame

If you already have an existent data frame, let's say df that has the columns you want, then you can just create an empty data frame by removing all the rows:

empty_df = df[FALSE,]

Notice that df still contains the data, but empty_df doesn't.

I found this question looking for how to create a new instance with empty rows, so I think it might be helpful for some people.

Calculating frames per second in a game

Here's a complete example, using Python (but easily adapted to any language). It uses the smoothing equation in Martin's answer, so almost no memory overhead, and I chose values that worked for me (feel free to play around with the constants to adapt to your use case).

import time

SMOOTHING_FACTOR = 0.99
MAX_FPS = 10000
avg_fps = -1
last_tick = time.time()

while True:
    # <Do your rendering work here...>

    current_tick = time.time()
    # Ensure we don't get crazy large frame rates, by capping to MAX_FPS
    current_fps = 1.0 / max(current_tick - last_tick, 1.0/MAX_FPS)
    last_tick = current_tick
    if avg_fps < 0:
        avg_fps = current_fps
    else:
        avg_fps = (avg_fps * SMOOTHING_FACTOR) + (current_fps * (1-SMOOTHING_FACTOR))
    print(avg_fps)

How to create an android app using HTML 5

you can use webview in android that will use chrome browser Or you can try Phonegap or sencha Touch

Calculate a MD5 hash from a string

I'd like to offer an alternative that appears to perform at least 10% faster than craigdfrench's answer in my tests (.NET 4.7.2):

public static string GetMD5Hash(string text)
{
    using ( var md5 = MD5.Create() )
    {
        byte[] computedHash = md5.ComputeHash( Encoding.UTF8.GetBytes(text) );
        return new System.Runtime.Remoting.Metadata.W3cXsd2001.SoapHexBinary(computedHash).ToString();
    }
}

If you prefer to have using System.Runtime.Remoting.Metadata.W3cXsd2001; at the top, the method body can be made an easier to read one-liner:

using ( var md5 = MD5.Create() )
{
    return new SoapHexBinary( md5.ComputeHash( Encoding.UTF8.GetBytes(text) ) ).ToString();
}

Obvious enough, but for completeness, in OP's context it would be used as:

sSourceData = "MySourceData";
tmpHash = GetMD5Hash(sSourceData);

Difference between document.addEventListener and window.addEventListener?

You'll find that in javascript, there are usually many different ways to do the same thing or find the same information. In your example, you are looking for some element that is guaranteed to always exist. window and document both fit the bill (with just a few differences).

From mozilla dev network:

addEventListener() registers a single event listener on a single target. The event target may be a single element in a document, the document itself, a window, or an XMLHttpRequest.

So as long as you can count on your "target" always being there, the only difference is what events you're listening for, so just use your favorite.

How to view/delete local storage in Firefox?

From Firefox 34 onwards you now have an option for Storage Inspector, which you can enable it from developer tools settings

Once there, you can enable the Storage options under Default Firefox Developer tools

Updated 27-3-16

Firefox 48.0a1 now supports Cookies editing.

Updated 3-4-16

Firefox 48.0a1 now supports localStorage and sessionStorage editing.

Updated 02-08-16

Firefox 48 (stable release) and onward supports editing of all storage types, except IndexedDB

How to use OrderBy with findAll in Spring Data

AFAIK, I don't think this is possible with a direct method naming query. You can however use the built in sorting mechanism, using the Sort class. The repository has a findAll(Sort) method that you can pass an instance of Sort to. For example:

import org.springframework.data.domain.Sort;

@Repository
public class StudentServiceImpl implements StudentService {
    @Autowired
    private StudentDAO studentDao;

    @Override
    public List<Student> findAll() {
        return studentDao.findAll(sortByIdAsc());
    }

    private Sort sortByIdAsc() {
        return new Sort(Sort.Direction.ASC, "id");
    }
} 

How to print spaces in Python?

First and foremost, for newlines, the simplest thing to do is have separate print statements, like this:

print("Hello")
print("World.")
#the parentheses allow it to work in Python 2, or 3.

To have a line break, and still only one print statement, simply use the "\n" within, as follows:

print("Hello\nWorld.")

Below, I explain spaces, instead of line breaks...

I see allot of people here using the + notation, which personally, I find ugly. Example of what I find ugly:

x=' ';
print("Hello"+10*x+"world"); 

The example above is currently, as I type this the top up-voted answer. The programmer is obviously coming into Python from PHP as the ";" syntax at the end of every line, well simple isn't needed. The only reason it doesn't through an error in Python is because semicolons CAN be used in Python, really should only be used when you are trying to place two lines on one, for aesthetic reasons. You shouldn't place these at the end of every line in Python, as it only increases file-size.

Personally, I prefer to use %s notation. In Python 2.7, which I prefer, you don't need the parentheses, "(" and ")". However, you should include them anyways, so your script won't through errors, in Python 3.x, and will run in either.

Let's say you wanted your space to be 8 spaces, So what I would do would be the following in Python > 3.x

print("Hello", "World.",  sep=' '*8, end="\n")
# you don't need to specify end, if you don't want to, but I wanted you to know it was also an option
#if you wanted to have an 8 space prefix, and did not wish to use tabs for some reason, you could do the following.
print("%sHello World." % (' '*8))

The above method will work in Python 2.x as well, but you cannot add the "sep" and "end" arguments, those have to be done manually in Python < 3.

Therefore, to have an 8 space prefix, with a 4 space separator, the syntax which would work in Python 2, or 3 would be:

print("%sHello%sWorld." % (' '*8, ' '*4))

I hope this helps.

P.S. You also could do the following.

>>> prefix=' '*8
>>> sep=' '*2
>>> print("%sHello%sWorld." % (prefix, sep))
    Hello  World.

Is there a way of setting culture for a whole application? All current threads and new threads?

This answer is a bit of expansion for @rastating's great answer. You can use the following code for all versions of .NET without any worries:

    public static void SetDefaultCulture(CultureInfo culture)
    {
        Type type = typeof (CultureInfo);
        try
        {
            // Class "ReflectionContext" exists from .NET 4.5 onwards.
            if (Type.GetType("System.Reflection.ReflectionContext", false) != null)
            {
                type.GetProperty("DefaultThreadCurrentCulture")
                    .SetValue(System.Threading.Thread.CurrentThread.CurrentCulture,
                        culture, null);

                type.GetProperty("DefaultThreadCurrentUICulture")
                    .SetValue(System.Threading.Thread.CurrentThread.CurrentCulture,
                        culture, null);
            }
            else //.NET 4 and lower
            {
                type.InvokeMember("s_userDefaultCulture",
                    BindingFlags.SetField | BindingFlags.NonPublic | BindingFlags.Static,
                    null,
                    culture,
                    new object[] {culture});

                type.InvokeMember("s_userDefaultUICulture",
                    BindingFlags.SetField | BindingFlags.NonPublic | BindingFlags.Static,
                    null,
                    culture,
                    new object[] {culture});

                type.InvokeMember("m_userDefaultCulture",
                    BindingFlags.SetField | BindingFlags.NonPublic | BindingFlags.Static,
                    null,
                    culture,
                    new object[] {culture});

                type.InvokeMember("m_userDefaultUICulture",
                    BindingFlags.SetField | BindingFlags.NonPublic | BindingFlags.Static,
                    null,
                    culture,
                    new object[] {culture});
            }
        }
        catch
        {
            // ignored
        }
    }
}

How to check the maximum number of allowed connections to an Oracle database?

There are a few different limits that might come in to play in determining the number of connections an Oracle database supports. The simplest approach would be to use the SESSIONS parameter and V$SESSION, i.e.

The number of sessions the database was configured to allow

SELECT name, value 
  FROM v$parameter
 WHERE name = 'sessions'

The number of sessions currently active

SELECT COUNT(*)
  FROM v$session

As I said, though, there are other potential limits both at the database level and at the operating system level and depending on whether shared server has been configured. If shared server is ignored, you may well hit the limit of the PROCESSES parameter before you hit the limit of the SESSIONS parameter. And you may hit operating system limits because each session requires a certain amount of RAM.

What is the difference between HTTP status code 200 (cache) vs status code 304?

This threw me for a long time too. The first thing I'd verify is that you're not reloading the page by clicking the refresh button, that will always issue a conditional request for resources and will return 304s for many of the page elements. Instead go up to the url bar select the page and hit enter as if you had just typed in the same URL again, that will give you a better indicator of what's being cached properly. This article does a great job explaining the difference between conditional and unconditional requests and how the refresh button affects them: http://blogs.msdn.com/b/ieinternals/archive/2010/07/08/technical-information-about-conditional-http-requests-and-the-refresh-button.aspx

How can I give the Intellij compiler more heap space?

Current version:

Settings (Preferences on Mac) | Build, Execution, Deployment | Compiler | Build process heap size.

Older versions:

Settings (Preferences on Mac) | Compiler | Java Compiler | Maximum heap size.

Compiler runs in a separate JVM by default so IDEA heap settings that you set in idea.vmoptions have no effect on the compiler.

What is username and password when starting Spring Boot with Tomcat?

You can also ask the user for the credentials and set them dynamically once the server starts (very effective when you need to publish the solution on a customer environment):

@EnableWebSecurity
public class SecurityConfig {

    private static final Logger log = LogManager.getLogger();

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        log.info("Setting in-memory security using the user input...");

        Scanner scanner = new Scanner(System.in);
        String inputUser = null;
        String inputPassword = null;
        System.out.println("\nPlease set the admin credentials for this web application");
        while (true) {
            System.out.print("user: ");
            inputUser = scanner.nextLine();
            System.out.print("password: ");
            inputPassword = scanner.nextLine();
            System.out.print("confirm password: ");
            String inputPasswordConfirm = scanner.nextLine();

            if (inputUser.isEmpty()) {
                System.out.println("Error: user must be set - please try again");
            } else if (inputPassword.isEmpty()) {
                System.out.println("Error: password must be set - please try again");
            } else if (!inputPassword.equals(inputPasswordConfirm)) {
                System.out.println("Error: password and password confirm do not match - please try again");
            } else {
                log.info("Setting the in-memory security using the provided credentials...");
                break;
            }
            System.out.println("");
        }
        scanner.close();

        if (inputUser != null && inputPassword != null) {
             auth.inMemoryAuthentication()
                .withUser(inputUser)
                .password(inputPassword)
                .roles("USER");
        }
    }
}

(May 2018) An update - this will work on spring boot 2.x:

@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    private static final Logger log = LogManager.getLogger();

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        // Note: 
        // Use this to enable the tomcat basic authentication (tomcat popup rather than spring login page)
        // Note that the CSRf token is disabled for all requests
        log.info("Disabling CSRF, enabling basic authentication...");
        http
        .authorizeRequests()
            .antMatchers("/**").authenticated() // These urls are allowed by any authenticated user
        .and()
            .httpBasic();
        http.csrf().disable();
    }

    @Bean
    public UserDetailsService userDetailsService() {
        log.info("Setting in-memory security using the user input...");

        String username = null;
        String password = null;

        System.out.println("\nPlease set the admin credentials for this web application (will be required when browsing to the web application)");
        Console console = System.console();

        // Read the credentials from the user console: 
        // Note: 
        // Console supports password masking, but is not supported in IDEs such as eclipse; 
        // thus if in IDE (where console == null) use scanner instead:
        if (console == null) {
            // Use scanner:
            Scanner scanner = new Scanner(System.in);
            while (true) {
                System.out.print("Username: ");
                username = scanner.nextLine();
                System.out.print("Password: ");
                password = scanner.nextLine();
                System.out.print("Confirm Password: ");
                String inputPasswordConfirm = scanner.nextLine();

                if (username.isEmpty()) {
                    System.out.println("Error: user must be set - please try again");
                } else if (password.isEmpty()) {
                    System.out.println("Error: password must be set - please try again");
                } else if (!password.equals(inputPasswordConfirm)) {
                    System.out.println("Error: password and password confirm do not match - please try again");
                } else {
                    log.info("Setting the in-memory security using the provided credentials...");
                    break;
                }
                System.out.println("");
            }
            scanner.close();
        } else {
            // Use Console
            while (true) {
                username = console.readLine("Username: ");
                char[] passwordChars = console.readPassword("Password: ");
                password = String.valueOf(passwordChars);
                char[] passwordConfirmChars = console.readPassword("Confirm Password: ");
                String passwordConfirm = String.valueOf(passwordConfirmChars);

                if (username.isEmpty()) {
                    System.out.println("Error: Username must be set - please try again");
                } else if (password.isEmpty()) {
                    System.out.println("Error: Password must be set - please try again");
                } else if (!password.equals(passwordConfirm)) {
                    System.out.println("Error: Password and Password Confirm do not match - please try again");
                } else {
                    log.info("Setting the in-memory security using the provided credentials...");
                    break;
                }
                System.out.println("");
            }
        }

        // Set the inMemoryAuthentication object with the given credentials:
        InMemoryUserDetailsManager manager = new InMemoryUserDetailsManager();
        if (username != null && password != null) {
            String encodedPassword = passwordEncoder().encode(password);
            manager.createUser(User.withUsername(username).password(encodedPassword).roles("USER").build());
        }
        return manager;
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
}

How do I set a ViewModel on a window in XAML using DataContext property?

Try this instead.

<Window x:Class="BuildAssistantUI.BuildAssistantWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:VM="clr-namespace:BuildAssistantUI.ViewModels">
    <Window.DataContext>
        <VM:MainViewModel />
    </Window.DataContext>
</Window>

How do I install a Python package with a .whl file?

In-case if you unable to install specific package directly using PIP.

You can download a specific .whl (wheel) package from - https://www.lfd.uci.edu/~gohlke/pythonlibs/

CD (Change directory) to that downloaded package and install it manually by -
pip install PACKAGENAME.whl
ex:
pip install ad3-2.1-cp27-cp27m-win32.whl

JQUERY: Uncaught Error: Syntax error, unrecognized expression

If you're using jQuery 2.1.4 or above, try this:

$("#" + this.d);

Or, you can define var before using it. It makes your code simpler.

var d = this.d
$("#" + d);

Conditionally change img src based on model data

<ul>
  <li ng-repeat=interface in interfaces>
       <img src='green-checkmark.png' ng-show="interface=='UP'" />
       <img src='big-black-X.png' ng-show="interface=='DOWN'" />
  </li>
</ul>

MySQL select with CONCAT condition

Try:

SELECT neededfield, CONCAT(firstname, ' ', lastname) as firstlast 
  FROM users 
WHERE CONCAT(firstname, ' ', lastname) = "Bob Michael Jones"

Your alias firstlast is not available in the where clause of the query unless you do the query as a sub-select.

How do I set default terminal to terminator?

The only way that worked for me was

  1. Open nautilus or nemo as root user gksudo nautilus
  2. Go to /usr/bin
  3. Change name of your default terminal to any other name for exemple "orig_gnome-terminal"
  4. rename your favorite terminal as "gnome-terminal"

How do I use method overloading in Python?

In Python, you'd do this with a default argument.

class A:

    def stackoverflow(self, i=None):    
        if i == None:
            print 'first method'
        else:
            print 'second method',i

lambda expression join multiple tables with select and where clause

I was looking for something and I found this post. I post this code that managed many-to-many relationships in case someone needs it.

    var UserInRole = db.UsersInRoles.Include(u => u.UserProfile).Include(u => u.Roles)
    .Select (m => new 
    {
        UserName = u.UserProfile.UserName,
        RoleName = u.Roles.RoleName
    });

usr/bin/ld: cannot find -l<nameOfTheLibrary>

To figure out what the linker is looking for, run it in verbose mode.

For example, I encountered this issue while trying to compile MySQL with ZLIB support. I was receiving an error like this during compilation:

/usr/bin/ld: cannot find -lzlib

I did some Googl'ing and kept coming across different issues of the same kind where people would say to make sure the .so file actually exists and if it doesn't, then create a symlink to the versioned file, for example, zlib.so.1.2.8. But, when I checked, zlib.so DID exist. So, I thought, surely that couldn't be the problem.

I came across another post on the Internets that suggested to run make with LD_DEBUG=all:

LD_DEBUG=all make

Although I got a TON of debugging output, it wasn't actually helpful. It added more confusion than anything else. So, I was about to give up.

Then, I had an epiphany. I thought to actually check the help text for the ld command:

ld --help

From that, I figured out how to run ld in verbose mode (imagine that):

ld -lzlib --verbose

This is the output I got:

==================================================
attempt to open /usr/x86_64-linux-gnu/lib64/libzlib.so failed
attempt to open /usr/x86_64-linux-gnu/lib64/libzlib.a failed
attempt to open /usr/local/lib64/libzlib.so failed
attempt to open /usr/local/lib64/libzlib.a failed
attempt to open /lib64/libzlib.so failed
attempt to open /lib64/libzlib.a failed
attempt to open /usr/lib64/libzlib.so failed
attempt to open /usr/lib64/libzlib.a failed
attempt to open /usr/x86_64-linux-gnu/lib/libzlib.so failed
attempt to open /usr/x86_64-linux-gnu/lib/libzlib.a failed
attempt to open /usr/local/lib/libzlib.so failed
attempt to open /usr/local/lib/libzlib.a failed
attempt to open /lib/libzlib.so failed
attempt to open /lib/libzlib.a failed
attempt to open /usr/lib/libzlib.so failed
attempt to open /usr/lib/libzlib.a failed
/usr/bin/ld.bfd.real: cannot find -lzlib

Ding, ding, ding...

So, to finally fix it so I could compile MySQL with my own version of ZLIB (rather than the bundled version):

sudo ln -s /usr/lib/libz.so.1.2.8 /usr/lib/libzlib.so

Voila!

AngularJS passing data to $http.get request

For sending get request with parameter i use

  $http.get('urlPartOne\\'+parameter+'\\urlPartTwo')

By this you can use your own url string

How to make a simple rounded button in Storyboard?

You can connect IBOutlet of yur button from storyboard.

Then you can set corner radius of your button to make it's corner round.

for example, your outlet is myButton then,

Obj - C

 self.myButton.layer.cornerRadius = 5.0 ;

Swift

  myButton.layer.cornerRadius = 5.0

If you want exact round button then your button's width and height must be equal and cornerRadius must be equal to height or width / 2 (half of the width or height).

How do you install Boost on MacOS?

You can get the latest version of Boost by using Homebrew.

brew install boost.

Can't clone a github repo on Linux via HTTPS

I was able to get a git 1.7.1 to work after quite some time.

First, I had to do disable SSL just so I could pull:

git config --global http.sslverify false

Then I could clone

git clone https://github.com/USERNAME/PROJECTNAME.git

Then after adding and committing i was UNABLE to push back. So i did

git remote -v

origin  https://github.com/USERNAME/PROJECTNAME.git (fetch)
origin  https://github.com/USERNAME/PROJECTNAME.git (push)

to see the pull and push adresses:

These must be modified with USERNAME@

git remote set-url origin https://[email protected]/USERNAME/PROJECTNAME.git

It will still prompt you for a password, which you could add with

USERNAME:PASSWORD@github.....

But dont do that, as you save your password in cleartext for easy theft.

I had to do this combination since I could not get SSH to work due to firewall limitations.

How to get info on sent PHP curl request

If you set CURLINFO_HEADER_OUT to true, outgoing headers are available in the array returned by curl_getinfo(), under request_header key:

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "http://foo.com/bar");
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
curl_setopt($ch, CURLOPT_USERPWD, "someusername:secretpassword");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLINFO_HEADER_OUT, true);

curl_exec($ch);

$info = curl_getinfo($ch);
print_r($info['request_header']);

This will print:

GET /bar HTTP/1.1
Authorization: Basic c29tZXVzZXJuYW1lOnNlY3JldHBhc3N3b3Jk
Host: foo.com
Accept: */*

Note the auth details are base64-encoded:

echo base64_decode('c29tZXVzZXJuYW1lOnNlY3JldHBhc3N3b3Jk');
// prints: someusername:secretpassword

Also note that username and password need to be percent-encoded to escape any URL reserved characters (/, ?, &, : and so on) they might contain:

curl_setopt($ch, CURLOPT_USERPWD, urlencode($username).':'.urlencode($password));

How to style CSS role

we can use

 element[role="ourRole"] {
    requried style !important; /*for overriding the old css styles */
    }

input() error - NameError: name '...' is not defined

I also encountered this issue with a module that was supposed to be compatible for python 2.7 and 3.7

what i found to fix the issue was importing:

from six.moves import input

this fixed the usability for both interpreters

you can read more about the six library here

How to print last two columns using awk

awk '{print $NF-1, $NF}'  inputfile

Note: this works only if at least two columns exist. On records with one column you will get a spurious "-1 column1"

How to remove "href" with Jquery?

Your title question and your example are completely different. I'll start by answering the title question:

$("a").removeAttr("href");

And as far as not requiring an href, the generally accepted way of doing this is:

<a href"#" onclick="doWork(); return false;">link</a>

The return false is necessary so that the href doesn't actually go anywhere.

iPad Multitasking support requires these orientations

I am using Xamarin and there is no available option in the UI to specify "Requires full screen". I, therefore, had to follow @Michael Wang's answer with a slight modification. Here goes:

Open the info.plist file in a text editor and add the lines:

<key>UIRequiresFullScreen</key>
<true/>

I tried setting the value to "YES" but it didn't work, which was kind of expected.

In case you are wondering, I placed the above lines below the UISupportedInterfaceOrientations section

<key>UISupportedInterfaceOrientations~ipad</key>
<array>
    <string>UIInterfaceOrientationPortrait</string>
    <string>UIInterfaceOrientationPortraitUpsideDown</string>
</array>

Hope this helps someone. Credit to Michael.

To get total number of columns in a table in sql

In MS-SQL Server 7+:

SELECT count(*)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'mytable'

Difference between java.exe and javaw.exe

The javaw.exe command is identical to java.exe, except that with javaw.exe there is no associated console window

SQL QUERY replace NULL value in a row with a value from the previous known value

I know it is a very old forum, but I came across this while troubleshooting my problem :) just realised that the other guys have given bit complex solution to the above problem. Please see my solution below:

DECLARE @A TABLE(ID INT, Val INT)

INSERT INTO @A(ID,Val) SELECT 1, 3
INSERT INTO @A(ID,Val) SELECT 2, NULL
INSERT INTO @A(ID,Val) SELECT 3, 5
INSERT INTO @A(ID,Val) SELECT 4, NULL
INSERT INTO @A(ID,Val) SELECT 5, NULL
INSERT INTO @A(ID,Val) SELECT 6, 2

UPDATE D
    SET D.VAL = E.VAL
    FROM (SELECT A.ID C_ID, MAX(B.ID) P_ID
          FROM  @A AS A
           JOIN @A AS B ON A.ID > B.ID
          WHERE A.Val IS NULL
            AND B.Val IS NOT NULL
          GROUP BY A.ID) AS C
    JOIN @A AS D ON C.C_ID = D.ID
    JOIN @A AS E ON C.P_ID = E.ID

SELECT * FROM @A

Hope this may help someone:)

Cannot connect to local SQL Server with Management Studio

I was having this problem on a Windows 7 (64 bit) after a power outage. The SQLEXPRESS service was not started even though is status was set to 'Automatic' and the mahine had been rebooted several times. Had to start the service manually.

Check whether a value is a number in JavaScript or jQuery

function isNumber(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}

How to create an XML document using XmlDocument?

Working with a dictionary ->level2 above comes from a dictionary in my case (just in case anybody will find it useful) Trying the first example I stumbled over this error: "This document already has a 'DocumentElement' node." I was inspired by the answer here

and edited my code: (xmlDoc.DocumentElement.AppendChild(body))

//a dictionary:
Dictionary<string, string> Level2Data 
{
    {"level2", "text"},
    {"level2", "other text"},
    {"same_level2", "more text"}
}
//xml Decalration:
XmlDocument xmlDoc = new XmlDocument();
XmlDeclaration xmlDeclaration = xmlDoc.CreateXmlDeclaration("1.0", "UTF-8", null);
XmlElement root = xmlDoc.DocumentElement;
xmlDoc.InsertBefore(xmlDeclaration, root);
// add body
XmlElement body = xmlDoc.CreateElement(string.Empty, "body", string.Empty);
xmlDoc.AppendChild(body);
XmlElement body = xmlDoc.CreateElement(string.Empty, "body", string.Empty);
xmlDoc.DocumentElement.AppendChild(body); //without DocumentElement ->ERR



foreach (KeyValuePair<string, string> entry in Level2Data)
{
    //write to xml: - it works version 1.
    XmlNode keyNode = xmlDoc.CreateElement(entry.Key); //open TAB
    keyNode.InnerText = entry.Value;
    body.AppendChild(keyNode); //close TAB

    //Write to xmml verdion 2: (uncomment the next 4 lines and comment the above 3 - version 1
    //XmlElement key = xmlDoc.CreateElement(string.Empty, entry.Key, string.Empty);
    //XmlText value = xmlDoc.CreateTextNode(entry.Value);
    //key.AppendChild(value);
    //body.AppendChild(key);
}

Both versions (1 and 2 inside foreach loop) give the output:

<?xml version="1.0" encoding="UTF-8"?>
<body>
    <level1>
        <level2>text</level2>
        <level2>ther text</level2>
         <same_level2>more text</same_level2>
    </level1>
</body>

(Note: third line "same level2" in dictionary can be also level2 as the others but I wanted to ilustrate the advantage of the dictionary - in my case I needed level2 with different names.