Programs & Examples On #Caldav

CalDAV (Calendaring Extensions to WebDAV) is an Internet standard allowing a client to access scheduling information on a remote server.

List files ONLY in the current directory

You can use the pathlib module.

from pathlib import Path
x = Path('./')
print(list(filter(lambda y:y.is_file(), x.iterdir())))

Find index of a value in an array

int keyIndex = Array.FindIndex(words, w => w.IsKey);

That actually gets you the integer index and not the object, regardless of what custom class you have created

How to pass in parameters when use resource service?

I think I see your problem, you need to use the @ syntax to define parameters you will pass in this way, also I'm not sure what loginID or password are doing you don't seem to define them anywhere and they are not being used as URL parameters so are they being sent as query parameters?

This is what I can suggest based on what I see so far:

.factory('MagComments', function ($resource) {
    return $resource('http://localhost/dooleystand/ci/api/magCommenct/:id', {
      loginID : organEntity,
      password : organCommpassword,
      id : '@magId'
    });
  })

The @magId string will tell the resource to replace :id with the property magId on the object you pass it as parameters.

I'd suggest reading over the documentation here (I know it's a bit opaque) very carefully and looking at the examples towards the end, this should help a lot.

Using Application context everywhere?

Application Class:

import android.app.Application;
import android.content.Context;

public class MyApplication extends Application {

    private static Context mContext;

    public void onCreate() {
        super.onCreate();
        mContext = getApplicationContext();
    }

    public static Context getAppContext() {
        return mContext;
    }

}

Declare the Application in the AndroidManifest:

<application android:name=".MyApplication"
    ...
/>

Usage:

MyApplication.getAppContext()

Using :focus to style outer div?

As per the spec:

The :focus pseudo-class applies while an element has the focus (accepts keyboard events or other forms of text input).

The <div> does not accept input, so it cannot have :focus. Furthermore, CSS does not allow you to set styles on an element based on targeting its descendants. So you can't really do this unless you are willing to use JavaScript.

IIS: Display all sites and bindings in PowerShell

Try something like this to get the format you wanted:

Get-WebBinding | % {
    $name = $_.ItemXPath -replace '(?:.*?)name=''([^'']*)(?:.*)', '$1'
    New-Object psobject -Property @{
        Name = $name
        Binding = $_.bindinginformation.Split(":")[-1]
    }
} | Group-Object -Property Name | 
Format-Table Name, @{n="Bindings";e={$_.Group.Binding -join "`n"}} -Wrap

SQL Server, division returns zero

In SQL Server direct division of two integer returns integer even if the result should be the float. There is an example below to get it across:

--1--
declare @weird_number_float float
set @weird_number_float=22/7
select @weird_number_float

--2--
declare @weird_number_decimal decimal(18,10)
set @weird_number_decimal=22/7 
select @weird_number_decimal

--3--
declare @weird_number_numeric numeric
set @weird_number_numeric=22/7 
select @weird_number_numeric

--Right way

declare @weird_number float
set @weird_number=cast(22 as float)/cast(7 as float)
select @weird_number

Just last block will return the 3,14285714285714. In spite of the second block defined with right precision the result will be 3.00000.

Get ALL User Friends Using Facebook Graph API - Android

In v2.0 of the Graph API, calling /me/friends returns the person's friends who also use the app.

In addition, in v2.0, you must request the user_friends permission from each user. user_friends is no longer included by default in every login. Each user must grant the user_friends permission in order to appear in the response to /me/friends. See the Facebook upgrade guide for more detailed information, or review the summary below.

The /me/friendlists endpoint and user_friendlists permission are not what you're after. This endpoint does not return the users friends - its lets you access the lists a person has made to organize their friends. It does not return the friends in each of these lists. This API and permission is useful to allow you to render a custom privacy selector when giving people the opportunity to publish back to Facebook.

If you want to access a list of non-app-using friends, there are two options:

  1. If you want to let your people tag their friends in stories that they publish to Facebook using your App, you can use the /me/taggable_friends API. Use of this endpoint requires review by Facebook and should only be used for the case where you're rendering a list of friends in order to let the user tag them in a post.

  2. If your App is a Game AND your Game supports Facebook Canvas, you can use the /me/invitable_friends endpoint in order to render a custom invite dialog, then pass the tokens returned by this API to the standard Requests Dialog.

In other cases, apps are no longer able to retrieve the full list of a user's friends (only those friends who have specifically authorized your app using the user_friends permission).

For apps wanting allow people to invite friends to use an app, you can still use the Send Dialog on Web or the new Message Dialog on iOS and Android.

How are ssl certificates verified?

The client has a pre-seeded store of SSL certificate authorities' public keys. There must be a chain of trust from the certificate for the server up through intermediate authorities up to one of the so-called "root" certificates in order for the server to be trusted.

You can examine and/or alter the list of trusted authorities. Often you do this to add a certificate for a local authority that you know you trust - like the company you work for or the school you attend or what not.

The pre-seeded list can vary depending on which client you use. The big SSL certificate vendors insure that their root certs are in all the major browsers ($$$).

Monkey-in-the-middle attacks are "impossible" unless the attacker has the private key of a trusted root certificate. Since the corresponding certificates are widely deployed, the exposure of such a private key would have serious implications for the security of eCommerce generally. Because of that, those private keys are very, very closely guarded.

String parsing in Java with delimiter tab "\t" using split

Try this:

String[] columnDetail = column.split("\t", -1);

Read the Javadoc on String.split(java.lang.String, int) for an explanation about the limit parameter of split function:

split

public String[] split(String regex, int limit)
Splits this string around matches of the given regular expression.
The array returned by this method contains each substring of this string that is terminated by another substring that matches the given expression or is terminated by the end of the string. The substrings in the array are in the order in which they occur in this string. If the expression does not match any part of the input then the resulting array has just one element, namely this string.

The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array. If the limit n is greater than zero then the pattern will be applied at most n - 1 times, the array's length will be no greater than n, and the array's last entry will contain all input beyond the last matched delimiter. If n is non-positive then the pattern will be applied as many times as possible and the array can have any length. If n is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.

The string "boo:and:foo", for example, yields the following results with these parameters:

Regex   Limit   Result
:   2   { "boo", "and:foo" }
:   5   { "boo", "and", "foo" }
:   -2  { "boo", "and", "foo" }
o   5   { "b", "", ":and:f", "", "" }
o   -2  { "b", "", ":and:f", "", "" }
o   0   { "b", "", ":and:f" }

When the last few fields (I guest that's your situation) are missing, you will get the column like this:

field1\tfield2\tfield3\t\t

If no limit is set to split(), the limit is 0, which will lead to that "trailing empty strings will be discarded". So you can just get just 3 fields, {"field1", "field2", "field3"}.

When limit is set to -1, a non-positive value, trailing empty strings will not be discarded. So you can get 5 fields with the last two being empty string, {"field1", "field2", "field3", "", ""}.

Error: fix the version conflict (google-services plugin)

For fire base to install properly all the versions of the fire base compiles must be in same version so

compile 'com.google.firebase:firebase-messaging:11.0.4' 
compile 'com.google.android.gms:play-services-maps:11.0.4' 
compile 'com.google.android.gms:play-services-location:11.0.4'

this is the correct way to do it.

Exception thrown inside catch block - will it be caught again?

As said above...
I would add that if you have trouble seeing what is going on, if you can't reproduce the issue in the debugger, you can add a trace before re-throwing the new exception (with the good old System.out.println at worse, with a good log system like log4j otherwise).

Jenkins fails when running "service start jenkins"

Similar problem on Ubuntu 16.04.

Setting up jenkins (2.72) ...
Job for jenkins.service failed because the control process exited with error code. See "systemctl status jenkins.service" and "journalctl -xe" for details.
invoke-rc.d: initscript jenkins, action "start" failed.
? jenkins.service - LSB: Start Jenkins at boot time
Loaded: loaded (/etc/init.d/jenkins; bad; vendor preset: enabled)
Active: failed (Result: exit-code) since Tue 2017-08-01 05:39:06 UTC; 7ms ago
Docs: man:systemd-sysv-generator(8)
Process: 3700 ExecStart=/etc/init.d/jenkins start (code=exited, status=1/FAILURE)

Aug 01 05:39:06 ip-0 systemd[1]: Starting LSB: Start Jenkins ....
Aug 01 05:39:06 ip-0 jenkins[3700]: ERROR: No Java executable ...
Aug 01 05:39:06 ip-0 jenkins[3700]: If you actually have java ...
Aug 01 05:39:06 ip-0 systemd[1]: jenkins.service: Control pro...1
Aug 01 05:39:06 ip-0 systemd[1]: Failed to start LSB: Start J....
Aug 01 05:39:06 ip-0 systemd[1]: jenkins.service: Unit entere....
Aug 01 05:39:06 ip-0 systemd[1]: jenkins.service: Failed with....

To fix the issue manually install Java Runtime Environment:

JDK version 9:

sudo apt install openjdk-9-jre

JDK version 8:

sudo apt install openjdk-8-jre

Open Jenkins configuration file:

sudo vi /etc/init.d/jenkins

Finally, append path to the new java executable (line 16):

PATH=/bin:/usr/bin:/sbin:/usr/sbin:/usr/lib/jvm/java-8-openjdk-amd64/bin/

How to write LaTeX in IPython Notebook?

I am using Jupyter Notebooks. I had to write

%%latex
$sin(x)/x$

to get a LaTex font.

Change IPython/Jupyter notebook working directory

Upper Solution may not work for you if you have installed latest version of Python in Windows. I have installed Python 3.6.0 :: Anaconda 4.3.0 (64-bit) and I wanted to change the working directory of iPython Notebook called Jupyter and this is how it worked for me.

Step-1 : Open your CMD and type following command.

Step1 : CMD

Step-2 : It has now generated a file in your .jupyter folder. For me, it's C:\Users\Admin.jupyter . There you will find a file called jupyter_notebook_config.py .Right click and edit it. Add the following line and set path of your working directory. Set your own working directory in place of "I:\STUDY\Y2-Trimester-1\Modern Data Science"

We are done. Now you can try restarting your Jupyter Notebook. Hope this is useful to you. Thanks

log4j configuration via JVM argument(s)?

This seems to have changed (probably with log4j2) to:

-Dlog4j.configurationFile=file:C:\Users\me\log4j.xml

See: https://logging.apache.org/log4j/2.x/manual/configuration.html

How to capitalize the first letter of text in a TextView in an Android Application

For future visitors, you can also (best IMHO) import WordUtil from Apache and add a lot of useful methods to you app, like capitalize as shown here:

How to capitalize the first character of each word in a string

pass **kwargs argument to another function with **kwargs

The ** syntax tells Python to collect keyword arguments into a dictionary. The save2 is passing it down as a non-keyword argument (a dictionary object). The openX is not seeing any keyword arguments so the **args doesn't get used. It's instead getting a third non-keyword argument (the dictionary). To fix that change the definition of the openX function.

def openX(filename, mode, kwargs):
    pass

What are the true benefits of ExpandoObject?

I think it will have a syntactic benefit, since you'll no longer be "faking" dynamically added properties by using a dictionary.

That, and interop with dynamic languages I would think.

Android Studio update -Error:Could not run build action using Gradle distribution

I had the same problem and I Just Invalidate caches/restart

Split string with JavaScript

var wrapper = $(document.body);

strings = [
    "19 51 2.108997",
    "20 47 2.1089"
];

$.each(strings, function(key, value) {
    var tmp = value.split(" ");
    $.each([
        tmp[0] + " " + tmp[1],
        tmp[2]
    ], function(key, value) {
        $("<span>" + value + "</span>").appendTo(wrapper);
    }); 
});

How to display a list inline using Twitter's Bootstrap

I couldn't find anything specific within the bootstrap.css file. So, I added the css to a custom css file.

.inline li {
    display: inline;
}

How to open remote files in sublime text 3

On server

Install rsub:

wget -O /usr/local/bin/rsub \https://raw.github.com/aurora/rmate/master/rmate
chmod a+x /usr/local/bin/rsub

On local

  1. Install rsub Sublime3 package:

On Sublime Text 3, open Package Manager (Ctrl-Shift-P on Linux/Win, Cmd-Shift-P on Mac, Install Package), and search for rsub and install it

  1. Open command line and connect to remote server:

ssh -R 52698:localhost:52698 server_user@server_address

  1. after connect to server run this command on server:

rsub path_to_file/file.txt

  1. File opening auto in Sublime 3

As of today (2018/09/05) you should use : https://github.com/randy3k/RemoteSubl because you can find it in packagecontrol.io while "rsub" is not present.

Convert string into Date type on Python

Use datetime.datetime.strptime:

>>> import datetime
>>> date = datetime.datetime.strptime('2012-02-10', '%Y-%m-%d')
>>> date.isoweekday()
5

Digital Certificate: How to import .cer file in to .truststore file using?

The way you import a .cer file into the trust store is the same way you'd import a .crt file from say an export from Firefox.

You do not have to put an alias and the password of the keystore, you can just type:

keytool -v -import -file somefile.crt  -alias somecrt -keystore my-cacerts

Preferably use the cacerts file that is already in your Java installation (jre\lib\security\cacerts) as it contains secure "popular" certificates.

Update regarding the differences of cer and crt (just to clarify) According to Apache with SSL - How to convert CER to CRT certificates? and user @Spawnrider

CER is a X.509 certificate in binary form, DER encoded.
CRT is a binary X.509 certificate, encapsulated in text (base-64) encoding.
It is not the same encoding.

Changing the CommandTimeout in SQL Management studio

Changing Command Execute Timeout in Management Studio:

Click on Tools -> Options

Select Query Execution from tree on left side and enter command timeout in "Execute Timeout" control.

Changing Command Timeout in Server:

In the object browser tree right click on the server which give you timeout and select "Properties" from context menu.

Now in "Server Properties -....." dialog click on "Connections" page in "Select a Page" list (on left side). On the right side you will get property

Remote query timeout (in seconds, 0 = no timeout):
[up/down control]

you can set the value in up/down control.

Reading from stdin

From the man read:

#include <unistd.h>
ssize_t read(int fd, void *buf, size_t count);

Input parameters:

  • int fd file descriptor is an integer and not a file pointer. The file descriptor for stdin is 0

  • void *buf pointer to buffer to store characters read by the read function

  • size_t count maximum number of characters to read

So you can read character by character with the following code:

char buf[1];

while(read(0, buf, sizeof(buf))>0) {
   // read() here read from stdin charachter by character
   // the buf[0] contains the character got by read()
   ....
}

Get HTML inside iframe using jQuery

this works for me because it works fine in ie8.

$('#iframe').contents().find("html").html();

but if you like to use javascript aside for jquery you may use like this

var iframe = document.getElementById('iframecontent');
var innerDoc = iframe.contentDocument || iframe.contentWindow.document;
var val_1 = innerDoc.getElementById('value_1').value;

How to force C# .net app to run only one instance in Windows?

This is what I use in my application:

static void Main()
{
  bool mutexCreated = false;
  System.Threading.Mutex mutex = new System.Threading.Mutex( true, @"Local\slimCODE.slimKEYS.exe", out mutexCreated );

  if( !mutexCreated )
  {
    if( MessageBox.Show(
      "slimKEYS is already running. Hotkeys cannot be shared between different instances. Are you sure you wish to run this second instance?",
      "slimKEYS already running",
      MessageBoxButtons.YesNo,
      MessageBoxIcon.Question ) != DialogResult.Yes )
    {
      mutex.Close();
      return;
    }
  }

  // The usual stuff with Application.Run()

  mutex.Close();
}

List all devices, partitions and volumes in Powershell

On Windows Powershell:

Get-PSDrive 
[System.IO.DriveInfo]::getdrives()
wmic diskdrive
wmic volume

Also the utility dskwipe: http://smithii.com/dskwipe

dskwipe.exe -l

Count all values in a matrix greater than a value

To count the number of values larger than x in any numpy array you can use:

n = len(matrix[matrix > x])

The boolean indexing returns an array that contains only the elements where the condition (matrix > x) is met. Then len() counts these values.

jQuery multiple conditions within if statement

i == 'InvKey' && i == 'PostDate' will never be true, since i can never equal two different things at once.

You're probably trying to write

if (i !== 'InvKey' && i !== 'PostDate')) 

DB2 Timestamp select statement

You might want to use TRUNC function on your column when comparing with string format, so it compares only till seconds, not milliseconds.

SELECT * FROM <table_name> WHERE id = 1 
AND TRUNC(usagetime, 'SS') = '2012-09-03 08:03:06';

If you wanted to truncate upto minutes, hours, etc. that is also possible, just use appropriate notation instead of 'SS':

hour ('HH'), minute('MI'), year('YEAR' or 'YYYY'), month('MONTH' or 'MM'), Day ('DD')

CORS header 'Access-Control-Allow-Origin' missing

You must have got the idea why you are getting this problem after going through above answers.

self.send_header('Access-Control-Allow-Origin', '*')

You just have to add the above line in your server side.

Get value from SimpleXMLElement Object

foreach($xml->code as $vals )
{ 
    unset($geonames);
    $vals=(array)$vals;
    foreach($vals as $key => $value)
      {
        $value=(array)$value;
        $geonames[$key]=$value[0];
      }
}
print_r($geonames);

Setting selected values for ng-options bound select elements

If using AngularJS 1.2 you can use 'track by' to tell Angular how to compare objects.

<select 
    ng-model="Choice.SelectedOption"                 
    ng-options="choice.Name for choice in Choice.Options track by choice.ID">
</select>

Updated fiddle http://jsfiddle.net/gFCzV/34/

how to print a string to console in c++

All you have to do is add:

#include <string>
using namespace std;

at the top. (BTW I know this was posted in 2013 but I just wanted to answer)

html select scroll bar

Horizontal scrollbars in a HTML Select are not natively supported. However, here's a way to create the appearance of a horizontal scrollbar:

1. First create a css class

<style type="text/css">
 .scrollable{
   overflow: auto;
   width: 70px; /* adjust this width depending to amount of text to display */
   height: 80px; /* adjust height depending on number of options to display */
   border: 1px silver solid;
 }
 .scrollable select{
   border: none;
 }
</style>

2. Wrap the SELECT inside a DIV - also, explicitly set the size to the number of options.

<div class="scrollable">
<select size="6" multiple="multiple">
    <option value="1" selected>option 1 The Long Option</option>
    <option value="2">option 2</option>
    <option value="3">option 3</option>
    <option value="4">option 4</option>
    <option value="5">option 5 Another Longer than the Long Option ;)</option>
    <option value="6">option 6</option>
</select>
</div>

Custom edit view in UITableViewCell while swipe left. Objective-C or Swift

If you want to use only text while making swipe actions then you can use iOS default swipe actions but if you want image and text, then you have to customize it. I have found a great tutorial and sample that can resolve this problem.

Try out this repository to get the custom swipe cell. You can add multiple option here.

http://iosbucket.blogspot.in/2016/04/custom-swipe-table-view-cell_16.html

https://github.com/pradeep7may/PKSwipeTableViewCell

enter image description here

How to print out more than 20 items (documents) in MongoDB's shell?

Could always do:

db.foo.find().forEach(function(f){print(tojson(f, '', true));});

To get that compact view.

Also, I find it very useful to limit the fields returned by the find so:

db.foo.find({},{name:1}).forEach(function(f){print(tojson(f, '', true));});

which would return only the _id and name field from foo.

Detect page change on DataTable

$('#tableId').on('draw.dt', function() {
    //This will get called when data table data gets redrawn to the      table.
});

Deck of cards JAVA

Here is some code. It uses 2 classes (Card.java and Deck.java) to accomplish this issue, and to top it off it auto sorts it for you when you create the deck object. :)

import java.util.*;

public class deck2 {
    ArrayList<Card> cards = new ArrayList<Card>();

    String[] values = {"A","2","3","4","5","6","7","8","9","10","J","Q","K"};
    String[] suit = {"Club", "Spade", "Diamond", "Heart"};

    static boolean firstThread = true;
    public deck2(){
        for (int i = 0; i<suit.length; i++) {
            for(int j=0; j<values.length; j++){
                this.cards.add(new Card(suit[i],values[j]));
            }
        }
        //shuffle the deck when its created
        Collections.shuffle(this.cards);

    }

    public ArrayList<Card> getDeck(){
        return cards;
    }

    public static void main(String[] args){
        deck2 deck = new deck2();

        //print out the deck.
        System.out.println(deck.getDeck());
    }

}


//separate class

public class Card {


    private String suit;
    private String value;


    public Card(String suit, String value){
        this.suit = suit;
        this.value = value;
    }
    public Card(){}
    public String getSuit(){
        return suit;
    }
    public void setSuit(String suit){
        this.suit = suit;
    }
    public String getValue(){
        return value;
    }
    public void setValue(String value){
        this.value = value;
    }

    public String toString(){
        return "\n"+value + " of "+ suit;
    }
}

Pie chart with jQuery

There is a new player in the field, offering advanced Navigation Charts that are using Canvas for super-smooth animations and performance:

https://zoomcharts.com/

Example of charts:

interactive pie chart

Documentation: https://zoomcharts.com/en/javascript-charts-library/charts-packages/pie-chart/

What is cool about this lib:

  • Others slice can be expanded
  • Pie offers drill down for hierarchical structures (see example)
  • write your own data source controller easily, or provide simple json file
  • export high res images out of box
  • full touch support, works smoothly on iPad, iPhone, android, etc.

enter image description here

Charts are free for non-commercial use, commercial licenses and technical support available as well.

Also interactive Time charts and Net Charts are there for you to use. enter image description here

enter image description here

Charts come with extensive API and Settings, so you can control every aspect of the charts.

Unsuccessful append to an empty NumPy array

numpy.append always copies the array before appending the new values. Your code is equivalent to the following:

import numpy as np
result = np.zeros((2,0))
new_result = np.append([result[0]],[1,2])
result[0] = new_result # ERROR: has shape (2,0), new_result has shape (2,)

Perhaps you mean to do this?

import numpy as np
result = np.zeros((2,0))
result = np.append([result[0]],[1,2])

Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect)

This error occurred for me when I was trying to update the same row from 2 different sessions. I updated a field in one browser while a second was open and had already stored the original object in its session. When I attempted to update from this second "stale" session I get the stale object error. In order to correct this I refetch my object to be updated from the database before I set the value to be updated, then save it as normal.

Complex numbers usage in python

In python, you can put ‘j’ or ‘J’ after a number to make it imaginary, so you can write complex literals easily:

>>> 1j
1j
>>> 1J
1j
>>> 1j * 1j
(-1+0j)

The ‘j’ suffix comes from electrical engineering, where the variable ‘i’ is usually used for current. (Reasoning found here.)

The type of a complex number is complex, and you can use the type as a constructor if you prefer:

>>> complex(2,3)
(2+3j)

A complex number has some built-in accessors:

>>> z = 2+3j
>>> z.real
2.0
>>> z.imag
3.0
>>> z.conjugate()
(2-3j)

Several built-in functions support complex numbers:

>>> abs(3 + 4j)
5.0
>>> pow(3 + 4j, 2)
(-7+24j)

The standard module cmath has more functions that handle complex numbers:

>>> import cmath
>>> cmath.sin(2 + 3j)
(9.15449914691143-4.168906959966565j)

JavaScript string encryption and decryption?

The existing answers which leverage SJCL, CryptoJS, and/or WebCrypto aren't necessarily wrong but they're not as safe as you might initially suspect. Generally you want to use libsodium. First I'll explain why, then how.

Why Not SJCL, CryptoJS, WebCrypto, etc.?

Short answer: In order for your encryption to actually be secure, these libraries expect you to make too many choices e.g. the block cipher mode (CBC, CTR, GCM; if you can't tell which of the three I just listed is secure to use and under what constraints, you shouldn't be burdened with this sort of choice at all).

Unless your job title is cryptography engineer, the odds are stacked against you implementing it securely.

Why to Avoid CryptoJS?

CryptoJS offers a handful of building blocks and expects you to know how to use them securely. It even defaults to CBC mode (archived).

Why is CBC mode bad?

Read this write-up on AES-CBC vulnerabilities.

Why to Avoid WebCrypto?

WebCrypto is a potluck standard, designed by committee, for purposes that are orthogonal to cryptography engineering. Specifically, WebCrypto was meant to replace Flash, not provide security.

Why to Avoid SJCL?

SJCL's public API and documentation begs users to encrypt data with a human-remembered password. This is rarely, if ever, what you want to do in the real world.

Additionally: Its default PBKDF2 round count is roughly 86 times as small as you want it to be. AES-128-CCM is probably fine.

Out of the three options above, SJCL is the least likely to end in tears. But there are better options available.

Why is Libsodium Better?

You don't need to choose between a menu of cipher modes, hash functions, and other needless options. You'll never risk screwing up your parameters and removing all security from your protocol.

Instead, libsodium just gives you simple options tuned for maximum security and minimalistic APIs.

  • crypto_box() / crypto_box_open() offer authenticated public-key encryption.
    • The algorithm in question combines X25519 (ECDH over Curve25519) and XSalsa20-Poly1305, but you don't need to know (or even care) about that to use it securely
  • crypto_secretbox() / crypto_secretbox_open() offer shared-key authenticated encryption.
    • The algorithm in question is XSalsa20-Poly1305, but you don't need to know/care

Additionally, libsodium has bindings in dozens of popular programming languages, so it's very likely that libsodium will just work when trying to interoperate with another programming stack. Also, libsodium tends to be very fast without sacrificing security.

How to Use Libsodium in JavaScript?

First, you need to decide one thing:

  1. Do you just want to encrypt/decrypt data (and maybe still somehow use the plaintext in database queries securely) and not worry about the details? Or...
  2. Do you need to implement a specific protocol?

If you selected the first option, get CipherSweet.js.

The documentation is available online. EncryptedField is sufficient for most use cases, but the EncryptedRow and EncryptedMultiRows APIs may be easier if you have a lot of distinct fields you want to encrypt.

With CipherSweet, you don't need to even know what a nonce/IV is to use it securely.

Additionally, this handles int/float encryption without leaking facts about the contents through ciphertext size.

Otherwise, you'll want sodium-plus, which is a user-friendly frontend to various libsodium wrappers. Sodium-Plus allows you to write performant, asynchronous, cross-platform code that's easy to audit and reason about.

To install sodium-plus, simply run...

npm install sodium-plus

There is currently no public CDN for browser support. This will change soon. However, you can grab sodium-plus.min.js from the latest Github release if you need it.

_x000D_
_x000D_
const { SodiumPlus } = require('sodium-plus');_x000D_
let sodium;_x000D_
_x000D_
(async function () {_x000D_
    if (!sodium) sodium = await SodiumPlus.auto();_x000D_
    let plaintext = 'Your message goes here';_x000D_
    let key = await sodium.crypto_secretbox_keygen();_x000D_
    let nonce = await sodium.randombytes_buf(24);_x000D_
    let ciphertext = await sodium.crypto_secretbox(_x000D_
        plaintext,_x000D_
        nonce,_x000D_
        key    _x000D_
    );_x000D_
    console.log(ciphertext.toString('hex'));_x000D_
_x000D_
    let decrypted = await sodium.crypto_secretbox_open(_x000D_
        ciphertext,_x000D_
        nonce,_x000D_
        key_x000D_
    );_x000D_
_x000D_
    console.log(decrypted.toString());_x000D_
})();
_x000D_
_x000D_
_x000D_

The documentation for sodium-plus is available on Github.

If you'd like a step-by-step tutorial, this dev.to article has what you're looking for.

Cannot get Kerberos service ticket: KrbException: Server not found in Kerberos database (7)

Consider adding

[appdefaults]
validate=false

to your /etc/krb5.conf. This can work around mismatching DNS.

ping: google.com: Temporary failure in name resolution

I've faced the exactly same problem but I've fixed it with another approache.

Using Ubuntu 18.04, first disable systemd-resolved service.

sudo systemctl disable systemd-resolved.service

Stop the service

sudo systemctl stop systemd-resolved.service

Then, remove the link to /run/systemd/resolve/stub-resolv.conf in /etc/resolv.conf

sudo rm /etc/resolv.conf

Add a manually created resolv.conf in /etc/

sudo vim /etc/resolv.conf

Add your prefered DNS server there

nameserver 208.67.222.222

I've tested this with success.

Bash script error [: !=: unary operator expected

Quotes!

if [ "$1" != -v ]; then

Otherwise, when $1 is completely empty, your test becomes:

[ != -v ]

instead of

[ "" != -v ]

...and != is not a unary operator (that is, one capable of taking only a single argument).

What's the difference between a web site and a web application?

The technical difference according to two features:
1. Where the "work" is done
2. What is being transferred to/from the server

Web app
1. The "work" is done at the browser (JavaScript)
2. Data is being transferred from/to the server
In comparison: Faster

Website
1. The "work" (most of it) is done at the server
2. Rendered pages (data + UI) are being transferred from the server
In comparison: Easier SEO

Replace all occurrences of a string in a data frame

Equivalent to "find and replace." Don't overthink it.

Try it with one:

library(tidyverse)
df <- data.frame(name = rep(letters[1:3], each = 3), var1 = rep('< 2', 9), var2 = rep('<3', 9))

df %>% 
  mutate(var1 = str_replace(var1, " ", ""))
#>   name var1 var2
#> 1    a   <2   <3
#> 2    a   <2   <3
#> 3    a   <2   <3
#> 4    b   <2   <3
#> 5    b   <2   <3
#> 6    b   <2   <3
#> 7    c   <2   <3
#> 8    c   <2   <3
#> 9    c   <2   <3

Apply to all

df %>% 
  mutate_all(funs(str_replace(., " ", "")))
#>   name var1 var2
#> 1    a   <2   <3
#> 2    a   <2   <3
#> 3    a   <2   <3
#> 4    b   <2   <3
#> 5    b   <2   <3
#> 6    b   <2   <3
#> 7    c   <2   <3
#> 8    c   <2   <3
#> 9    c   <2   <3

If the extra space was produced by uniting columns, think about making str_trim part of your workflow.

Created on 2018-03-11 by the reprex package (v0.2.0).

sql try/catch rollback/commit - preventing erroneous commit after rollback

In your first example, you are correct. The batch will hit the commit transaction, regardless of whether the try block fires.

In your second example, I agree with other commenters. Using the success flag is unnecessary.

I consider the following approach to be, essentially, a light weight best practice approach.

If you want to see how it handles an exception, change the value on the second insert from 255 to 256.

CREATE TABLE #TEMP ( ID TINYINT NOT NULL );
INSERT  INTO #TEMP( ID ) VALUES  ( 1 )

BEGIN TRY
    BEGIN TRANSACTION

    INSERT  INTO #TEMP( ID ) VALUES  ( 2 )
    INSERT  INTO #TEMP( ID ) VALUES  ( 255 )

    COMMIT TRANSACTION
END TRY
BEGIN CATCH
    DECLARE 
        @ErrorMessage NVARCHAR(4000),
        @ErrorSeverity INT,
        @ErrorState INT;
    SELECT 
        @ErrorMessage = ERROR_MESSAGE(),
        @ErrorSeverity = ERROR_SEVERITY(),
        @ErrorState = ERROR_STATE();
    RAISERROR (
        @ErrorMessage,
        @ErrorSeverity,
        @ErrorState    
        );
    ROLLBACK TRANSACTION
END CATCH

SET NOCOUNT ON

SELECT ID
FROM #TEMP

DROP TABLE #TEMP

regular expression for finding 'href' value of a <a> link

I'd recommend using an HTML parser over a regex, but still here's a regex that will create a capturing group over the value of the href attribute of each links. It will match whether double or single quotes are used.

<a\s+(?:[^>]*?\s+)?href=(["'])(.*?)\1

You can view a full explanation of this regex at here.

Snippet playground:

_x000D_
_x000D_
const linkRx = /<a\s+(?:[^>]*?\s+)?href=(["'])(.*?)\1/;_x000D_
const textToMatchInput = document.querySelector('[name=textToMatch]');_x000D_
_x000D_
document.querySelector('button').addEventListener('click', () => {_x000D_
  console.log(textToMatchInput.value.match(linkRx));_x000D_
});
_x000D_
<label>_x000D_
  Text to match:_x000D_
  <input type="text" name="textToMatch" value='<a href="google.com"'>_x000D_
  _x000D_
  <button>Match</button>_x000D_
 </label>
_x000D_
_x000D_
_x000D_

Combine multiple JavaScript files into one JS file

You can use a script that I made. You need JRuby to run this though. https://bitbucket.org/ardee_aram/jscombiner (JSCombiner).

What sets this apart is that it watches file changes in the javascript, and combines it automatically to the script of your choice. So there is no need to manually "build" your javascript each time you test it. Hope it helps you out, I am currently using this.

Postgres FOR LOOP

Below is example you can use:

create temp table test2 (
  id1  numeric,
  id2  numeric,
  id3  numeric,
  id4  numeric,
  id5  numeric,
  id6  numeric,
  id7  numeric,
  id8  numeric,
  id9  numeric,
  id10 numeric) 
with (oids = false);

do
$do$
declare
     i int;
begin
for  i in 1..100000
loop
    insert into test2  values (random(), i * random(), i / random(), i + random(), i * random(), i / random(), i + random(), i * random(), i / random(), i + random());
end loop;
end;
$do$;

How do I check if the mouse is over an element in jQuery?

I took SLaks' idea and wrapped it in a small class.

function HoverWatcher(selector){
  this.hovering = false;
  var self = this; 

  this.isHoveringOver = function() { 
    return self.hovering; 
  } 

    $(selector).hover(function() { 
      self.hovering = true; 
    }, function() { 
      self.hovering = false; 
    }) 
} 

var box1Watcher = new HoverWatcher('#box1');
var box2Watcher = new HoverWatcher('#box2');



$('#container').click(function() {
  alert("box1.hover = " + box1Watcher.isHoveringOver() +
        ", box2.hover = " + box2Watcher.isHoveringOver());
});

How to apply style classes to td classes?

Simply create a Class Name and define your style there like this :

table.tdfont td {
  font-size: 0.9em;
}

Handling a Menu Item Click Event - Android

Menu items file looks like

res/menu/menu_main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context=".MainActivity">
    <item
        android:id="@+id/settings"
        android:title="Setting"
        app:showAsAction="never" />
    <item
        android:id="@+id/my_activity"
        android:title="My Activity"
        app:showAsAction="always"
        android:icon="@android:drawable/btn_radio"/>
</menu>

Java code looks like

src/MainActivity.java

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

      if (id == R.id.my_activity) {
            Intent intent1 = new Intent(this,MyActivity.class);
            this.startActivity(intent1);
            return true;
        }

        if (id == R.id.settings) {
            Toast.makeText(this, "Setting", Toast.LENGTH_LONG).show();
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

And add following code to your AndroidManifest.xml file

<activity
            android:name=".MyActivity"
            android:label="@string/app_name" >
        </activity>

I hope it will help you.

Run a command over SSH with JSch

using ssh from java should not be as hard as jsch makes it. you might be better off with sshj.

Datagrid binding in WPF

Without seeing said object list, I believe you should be binding to the DataGrid's ItemsSource property, not its DataContext.

<DataGrid x:Name="Imported" VerticalAlignment="Top" ItemsSource="{Binding Source=list}"  AutoGenerateColumns="False" CanUserResizeColumns="True">
    <DataGrid.Columns>                
        <DataGridTextColumn Header="ID" Binding="{Binding ID}"/>
        <DataGridTextColumn Header="Date" Binding="{Binding Date}"/>
   </DataGrid.Columns>
</DataGrid>

(This assumes that the element [UserControl, etc.] that contains the DataGrid has its DataContext bound to an object that contains the list collection. The DataGrid is derived from ItemsControl, which relies on its ItemsSource property to define the collection it binds its rows to. Hence, if list isn't a property of an object bound to your control's DataContext, you might need to set both DataContext={Binding list} and ItemsSource={Binding list} on the DataGrid...)

Push git commits & tags simultaneously

Update August 2020

As mentioned originally in this answer by SoBeRich, and in my own answer, as of git 2.4.x

git push --atomic origin <branch name> <tag>

(Note: this actually work with HTTPS only with Git 2.24)

Update May 2015

As of git 2.4.1, you can do

git config --global push.followTags true

If set to true enable --follow-tags option by default.
You may override this configuration at time of push by specifying --no-follow-tags.

As noted in this thread by Matt Rogers answering Wes Hurd:

--follow-tags only pushes annotated tags.

git tag -a -m "I'm an annotation" <tagname>

That would be pushed (as opposed to git tag <tagname>, a lightweight tag, which would not be pushed, as I mentioned here)

Update April 2013

Since git 1.8.3 (April 22d, 2013), you no longer have to do 2 commands to push branches, and then to push tags:

The new "--follow-tags" option tells "git push" to push relevant annotated tags when pushing branches out.

You can now try, when pushing new commits:

git push --follow-tags

That won't push all the local tags though, only the one referenced by commits which are pushed with the git push.

Git 2.4.1+ (Q2 2015) will introduce the option push.followTags: see "How to make “git push” include tags within a branch?".

Original answer, September 2010

The nuclear option would be git push --mirror, which will push all refs under refs/.

You can also push just one tag with your current branch commit:

git push origin : v1.0.0 

You can combine the --tags option with a refspec like:

git push origin --tags :

(since --tags means: All refs under refs/tags are pushed, in addition to refspecs explicitly listed on the command line)


You also have this entry "Pushing branches and tags with a single "git push" invocation"

A handy tip was just posted to the Git mailing list by Zoltán Füzesi:

I use .git/config to solve this:

[remote "origin"]
    url = ...
    fetch = +refs/heads/*:refs/remotes/origin/*
    push = +refs/heads/*
    push = +refs/tags/*

With these lines added git push origin will upload all your branches and tags. If you want to upload only some of them, you can enumerate them.

Haven't tried it myself yet, but it looks like it might be useful until some other way of pushing branches and tags at the same time is added to git push.
On the other hand, I don't mind typing:

$ git push && git push --tags

Beware, as commented by Aseem Kishore

push = +refs/heads/* will force-pushes all your branches.

This bit me just now, so FYI.


René Scheibe adds this interesting comment:

The --follow-tags parameter is misleading as only tags under .git/refs/tags are considered.
If git gc is run, tags are moved from .git/refs/tags to .git/packed-refs. Afterwards git push --follow-tags ... does not work as expected anymore.

Purpose of #!/usr/bin/python3 shebang

That's called a hash-bang. If you run the script from the shell, it will inspect the first line to figure out what program should be started to interpret the script.

A non Unix based OS will use its own rules for figuring out how to run the script. Windows for example will use the filename extension and the # will cause the first line to be treated as a comment.

If the path to the Python executable is wrong, then naturally the script will fail. It is easy to create links to the actual executable from whatever location is specified by standard convention.

Spark DataFrame groupBy and sort in the descending order (pyspark)

In pyspark 2.4.4

1) group_by_dataframe.count().filter("`count` >= 10").orderBy('count', ascending=False)

2) from pyspark.sql.functions import desc
   group_by_dataframe.count().filter("`count` >= 10").orderBy('count').sort(desc('count'))

No need to import in 1) and 1) is short & easy to read,
So I prefer 1) over 2)

How to install mechanize for Python 2.7?

Try this on Debian/Ubuntu:

sudo apt-get install python-mechanize

Set default format of datetimepicker as dd-MM-yyyy

You could easily use:

label1.Text = dateTimePicker1.Value.Date.ToString("dd/MM/yyyy")

and if you want to change '/' or '-', just add this:

label1.Text = label1.Text.Replace(".", "-")

More info about DateTimePicker.CustomFormat Property: Link

Adding a custom header to HTTP request using angular.js

And what's the answer from the server? It should reply a 204 and then really send the GET you are requesting.

In the OPTIONS the client is checking if the server allows CORS requests. If it gives you something different than a 204 then you should configure your server to send the correct Allow-Origin headers.

The way you are adding headers is the right way to do it.

Emulate a 403 error page

For this you must first say for the browser that the user receive an error 403. For this you can use this code:

header("HTTP/1.1 403 Forbidden" );

Then, the script send "error, error, error, error, error.......", so you must stop it. You can use

exit;

With this two lines the server send an error and stop the script.

Don't forget : that emulate the error, but you must set it in a .htaccess file, with

ErrorDocument 403 /error403.php

What is the best place for storing uploaded images, SQL database or disk file system?

For auto resizing, try imagemagick... it is used for many major open source content/photo management systems... and I believe that there are some .net extensions for it.

Accessing localhost:port from Android emulator

For Laravel Homestead Users: If anyone using Laravel with homestead you can access app backend using 192.168.10.10 in emulator

Still not working? Another good solution is to use ngrok https://ngrok.com/

WHERE statement after a UNION in SQL?

You probably need to wrap the UNION in a sub-SELECT and apply the WHERE clause afterward:

SELECT * FROM (
    SELECT * FROM Table1 WHERE Field1 = Value1
    UNION
    SELECT * FROM Table2 WHERE Field1 = Value2
) AS t WHERE Field2 = Value3

Basically, the UNION is looking for two complete SELECT statements to combine, and the WHERE clause is part of the SELECT statement.

It may make more sense to apply the outer WHERE clause to both of the inner queries. You'll probably want to benchmark the performance of both approaches and see which works better for you.

Adding Text to DataGridView Row Header

foreach (DataGridViewRow row in datagrid.Rows)
                        row.HeaderCell.Value = String.Format("{0}", row.Index + 1);

SyntaxError of Non-ASCII character

You should define source code encoding, add this to the top of your script:

# -*- coding: utf-8 -*-

The reason why it works differently in console and in the IDE is, likely, because of different default encodings set. You can check it by running:

import sys
print sys.getdefaultencoding()

Also see:

How to access Session variables and set them in javascript?

Try This

var sessionValue = '<%=Session["usedData"]%>'

JavaScript unit test tools for TDD

You might also be interested in the unit testing framework that is part of qooxdoo, an open source RIA framework similar to Dojo, ExtJS, etc. but with quite a comprehensive tool chain.

Try the online version of the testrunner. Hint: hit the gray arrow at the top left (should be made more obvious). It's a "play" button that runs the selected tests.

To find out more about the JS classes that let you define your unit tests, see the online API viewer.

For automated UI testing (based on Selenium RC), check out the Simulator project.

In which conda environment is Jupyter executing?

You can also switch environments in Anaconda Navigator, install Jupiter and run it. Anaconda Navigator

Windows Scheduled task succeeds but returns result 0x1

For Powershell scripts

I have seen this problem multiple times while scheduling Powershell scripts with parameters on multiple Windows servers. The solution has always been to use the -File parameter:

  1. Under "Actions" --> "Program / Script" Type: "Powershell"
  2. Under "Add arguments", instead of just typeing "C:/script/test.ps1" use -File "C:/script/test.ps1"

Happy scheduling!

enter image description here

Threads vs Processes in Linux

I think everyone has done a great job responding to your question. I'm just adding more information about thread versus process in Linux to clarify and summarize some of the previous responses in context of kernel. So, my response is in regarding to kernel specific code in Linux. According to Linux Kernel documentation, there is no clear distinction between thread versus process except thread uses shared virtual address space unlike process. Also note, the Linux Kernel uses the term "task" to refer to process and thread in general.

"There are no internal structures implementing processes or threads, instead there is a struct task_struct that describe an abstract scheduling unit called task"

Also according to Linus Torvalds, you should NOT think about process versus thread at all and because it's too limiting and the only difference is COE or Context of Execution in terms of "separate the address space from the parent " or shared address space. In fact he uses a web server example to make his point here (which highly recommend reading).

Full credit to linux kernel documentation

Spell Checker for Python

Try jamspell - it works pretty well for automatic spelling correction:

import jamspell

corrector = jamspell.TSpellCorrector()
corrector.LoadLangModel('en.bin')

corrector.FixFragment('Some sentnec with error')
# u'Some sentence with error'

corrector.GetCandidates(['Some', 'sentnec', 'with', 'error'], 1)
# ('sentence', 'senate', 'scented', 'sentinel')

What are the basic rules and idioms for operator overloading?

Overloading new and delete

Note: This only deals with the syntax of overloading new and delete, not with the implementation of such overloaded operators. I think that the semantics of overloading new and delete deserve their own FAQ, within the topic of operator overloading I can never do it justice.

Basics

In C++, when you write a new expression like new T(arg) two things happen when this expression is evaluated: First operator new is invoked to obtain raw memory, and then the appropriate constructor of T is invoked to turn this raw memory into a valid object. Likewise, when you delete an object, first its destructor is called, and then the memory is returned to operator delete.
C++ allows you to tune both of these operations: memory management and the construction/destruction of the object at the allocated memory. The latter is done by writing constructors and destructors for a class. Fine-tuning memory management is done by writing your own operator new and operator delete.

The first of the basic rules of operator overloading – don’t do it – applies especially to overloading new and delete. Almost the only reasons to overload these operators are performance problems and memory constraints, and in many cases, other actions, like changes to the algorithms used, will provide a much higher cost/gain ratio than attempting to tweak memory management.

The C++ standard library comes with a set of predefined new and delete operators. The most important ones are these:

void* operator new(std::size_t) throw(std::bad_alloc); 
void  operator delete(void*) throw(); 
void* operator new[](std::size_t) throw(std::bad_alloc); 
void  operator delete[](void*) throw(); 

The first two allocate/deallocate memory for an object, the latter two for an array of objects. If you provide your own versions of these, they will not overload, but replace the ones from the standard library.
If you overload operator new, you should always also overload the matching operator delete, even if you never intend to call it. The reason is that, if a constructor throws during the evaluation of a new expression, the run-time system will return the memory to the operator delete matching the operator new that was called to allocate the memory to create the object in. If you do not provide a matching operator delete, the default one is called, which is almost always wrong.
If you overload new and delete, you should consider overloading the array variants, too.

Placement new

C++ allows new and delete operators to take additional arguments.
So-called placement new allows you to create an object at a certain address which is passed to:

class X { /* ... */ };
char buffer[ sizeof(X) ];
void f()
{ 
  X* p = new(buffer) X(/*...*/);
  // ... 
  p->~X(); // call destructor 
} 

The standard library comes with the appropriate overloads of the new and delete operators for this:

void* operator new(std::size_t,void* p) throw(std::bad_alloc); 
void  operator delete(void* p,void*) throw(); 
void* operator new[](std::size_t,void* p) throw(std::bad_alloc); 
void  operator delete[](void* p,void*) throw(); 

Note that, in the example code for placement new given above, operator delete is never called, unless the constructor of X throws an exception.

You can also overload new and delete with other arguments. As with the additional argument for placement new, these arguments are also listed within parentheses after the keyword new. Merely for historical reasons, such variants are often also called placement new, even if their arguments are not for placing an object at a specific address.

Class-specific new and delete

Most commonly you will want to fine-tune memory management because measurement has shown that instances of a specific class, or of a group of related classes, are created and destroyed often and that the default memory management of the run-time system, tuned for general performance, deals inefficiently in this specific case. To improve this, you can overload new and delete for a specific class:

class my_class { 
  public: 
    // ... 
    void* operator new();
    void  operator delete(void*,std::size_t);
    void* operator new[](size_t);
    void  operator delete[](void*,std::size_t);
    // ... 
}; 

Overloaded thus, new and delete behave like static member functions. For objects of my_class, the std::size_t argument will always be sizeof(my_class). However, these operators are also called for dynamically allocated objects of derived classes, in which case it might be greater than that.

Global new and delete

To overload the global new and delete, simply replace the pre-defined operators of the standard library with our own. However, this rarely ever needs to be done.

Importing json file in TypeScript

With TypeScript 2.9.+ you can simply import JSON files with typesafety and intellisense like this:

import colorsJson from '../colors.json'; // This import style requires "esModuleInterop", see "side notes"
console.log(colorsJson.primaryBright);

Make sure to add these settings in the compilerOptions section of your tsconfig.json (documentation):

"resolveJsonModule": true,
"esModuleInterop": true,

Side notes:

  • Typescript 2.9.0 has a bug with this JSON feature, it was fixed with 2.9.2
  • The esModuleInterop is only necessary for the default import of the colorsJson. If you leave it set to false then you have to import it with import * as colorsJson from '../colors.json'

how to destroy bootstrap modal window completely?

The power of jQuery. $(selector).modal('hide').destroy(); will first remove sinds you might have the sliding affect and then removes the element completely, however if you want the user to be able to open the modal again after you finished the steps. you might just wanna update only the settings you wanna have reseted so for reseting all the inputs in your modal this would look like the following:

$(selector).find('input, textarea').each(function(){
   $(this).val('');
});

android button selector

You can't achieve text size change with a state list drawable. To change text color and text size do this:

Text color

To change the text color, you can create color state list resource. It will be a separate resource located in res/color/ directory. In layout xml you have to set it as the value for android:textColor attribute. The color selector will then contain something like this:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true" android:color="@color/text_pressed" />
    <item android:color="@color/text_normal" />
</selector>

Text size

You can't change the size of the text simply with resources. There's no "dimen selector". You have to do it in code. And there is no straightforward solution.

Probably the easiest solution might be utilizing View.onTouchListener() and handle the up and down events accordingly. Use something like this:

view.setOnTouchListener(new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                // change text size to the "pressed value"
                return true;
            case MotionEvent.ACTION_UP:
                // change text size to the "normal value"
                return true;
            default:
                return false;
            }
        }
});

A different solution might be to extend the view and override the setPressed(Boolean) method. The method is internally called when the change of the pressed state happens. Then change the size of the text accordingly in the method call (don't forget to call the super).

Stopping python using ctrl+c

Capture the KeyboardInterrupt (which is launched by pressing ctrl+c) and force the exit:

from sys import exit

try:
    # Your code
    command = input('Type your command: ')

except KeyboardInterrupt:
    # User interrupt the program with ctrl+c
    exit()

How to access child's state in React?

Just before I go into detail about how you can access the state of a child component, please make sure to read Markus-ipse's answer regarding a better solution to handle this particular scenario.

If you do indeed wish to access the state of a component's children, you can assign a property called ref to each child. There are now two ways to implement references: Using React.createRef() and callback refs.

Using React.createRef()

This is currently the recommended way to use references as of React 16.3 (See the docs for more info). If you're using an earlier version then see below regarding callback references.

You'll need to create a new reference in the constructor of your parent component and then assign it to a child via the ref attribute.

class FormEditor extends React.Component {
  constructor(props) {
    super(props);
    this.FieldEditor1 = React.createRef();
  }
  render() {
    return <FieldEditor ref={this.FieldEditor1} />;
  }
}

In order to access this kind of ref, you'll need to use:

const currentFieldEditor1 = this.FieldEditor1.current;

This will return an instance of the mounted component so you can then use currentFieldEditor1.state to access the state.

Just a quick note to say that if you use these references on a DOM node instead of a component (e.g. <div ref={this.divRef} />) then this.divRef.current will return the underlying DOM element instead of a component instance.

Callback Refs

This property takes a callback function that is passed a reference to the attached component. This callback is executed immediately after the component is mounted or unmounted.

For example:

<FieldEditor
    ref={(fieldEditor1) => {this.fieldEditor1 = fieldEditor1;}
    {...props}
/>

In these examples the reference is stored on the parent component. To call this component in your code, you can use:

this.fieldEditor1

and then use this.fieldEditor1.state to get the state.

One thing to note, make sure your child component has rendered before you try to access it ^_^

As above, if you use these references on a DOM node instead of a component (e.g. <div ref={(divRef) => {this.myDiv = divRef;}} />) then this.divRef will return the underlying DOM element instead of a component instance.

Further Information

If you want to read more about React's ref property, check out this page from Facebook.

Make sure you read the "Don't Overuse Refs" section that says that you shouldn't use the child's state to "make things happen".

Hope this helps ^_^

Edit: Added React.createRef() method for creating refs. Removed ES5 code.

org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update

You may need to handle javax.persistence.RollbackException

How do you do exponentiation in C?

use the pow function (it takes floats/doubles though).

man pow:

   #include <math.h>

   double pow(double x, double y);
   float powf(float x, float y);
   long double powl(long double x, long double y);

EDIT: For the special case of positive integer powers of 2, you can use bit shifting: (1 << x) will equal 2 to the power x. There are some potential gotchas with this, but generally, it would be correct.

Check that an email address is valid on iOS

to validate the email string you will need to write a regular expression to check it is in the correct form. there are plenty out on the web but be carefull as some can exclude what are actually legal addresses.

essentially it will look something like this

^((?>[a-zA-Z\d!#$%&'*+\-/=?^_`{|}~]+\x20*|"((?=[\x01-\x7f])[^"\\]|\\[\x01-\x7f])*"\x20*)*(?<angle><))?((?!\.)(?>\.?[a-zA-Z\d!#$%&'*+\-/=?^_`{|}~]+)+|"((?=[\x01-\x7f])[^"\\]|\\[\x01-\x7f])*")@(((?!-)[a-zA-Z\d\-]+(?<!-)\.)+[a-zA-Z]{2,}|\[(((?(?<!\[)\.)(25[0-5]|2[0-4]\d|[01]?\d?\d)){4}|[a-zA-Z\d\-]*[a-zA-Z\d]:((?=[\x01-\x7f])[^\\\[\]]|\\[\x01-\x7f])+)\])(?(angle)>)$

Actually checking if the email exists and doesn't bounce would mean sending an email and seeing what the result was. i.e. it bounced or it didn't. However it might not bounce for several hours or not at all and still not be a "real" email address. There are a number of services out there which purport to do this for you and would probably be paid for by you and quite frankly why bother to see if it is real?

It is good to check the user has not misspelt their email else they could enter it incorrectly, not realise it and then get hacked of with you for not replying. However if someone wants to add a bum email address there would be nothing to stop them creating it on hotmail or yahoo (or many other places) to gain the same end.

So do the regular expression and validate the structure but forget about validating against a service.

TypeError : Unhashable type

... and so you should do something like this:

set(tuple ((a,b) for a in range(3)) for b in range(3))

... and if needed convert back to list

Detect if the device is iPhone X

In Portrait only I use the view's frame's width and height to check:

override func viewDidLoad() {
    super.viewDidLoad()

    // iPhone Xr: -414 x 896
    // iPhone Xs Max: -414 x 896
    // iPhone X, Xs: -375 x 812

    if view.frame.width == 414 && view.frame.height == 896 || view.frame.width == 375 && view.frame.height == 812  {

        print("iPhone X")
    } else {

        print("not iPhone X")
    }

}

The portrait screen dimensions are listed here

enter image description here

UPDATE

This is answer is old and now that there are more X series in the iPhone lineup you would either have to list all of those dimensions inside the the if-else or it would be much easier to just check to see if the device has a notch. I got this answer/code from somewhere on SO about 1.5 yrs ago. If I could link to the code I would.

// 1. add an extension to UIDevice with this computed property
extension UIDevice {
    
    var hasTopNotch: Bool {
        if #available(iOS 11.0, tvOS 11.0, *) {
            return UIApplication.shared.delegate?.window??.safeAreaInsets.top ?? 0 > 20
        }
        return false
    }
} 

// 2. to use in any class
override func viewDidLoad() {
    super.viewDidLoad()

    if UIDevice.current.hasTopNotch {

        print("X series")

    } else {

        print("regular phone")
    }
}

How to get Chrome to allow mixed content?

Another solution which is permanent in nature between sessions without requiring you to run a specific command when opening chrome is as follows:

  1. Open a Chrome window
  2. In the URL bar enter Chrome://net-internals
  3. Click on "Domain Security Policy" in the side-bar
  4. Add the domain name which you want to always be able to access in http form into the "Add HSTS/PKP domain" section

Convert JSON to DataTable

json = File.ReadAllText(System.AppDomain.CurrentDomain.BaseDirectory + "App_Data\\" +download_file[0]);
DataTable dt = (DataTable)JsonConvert.DeserializeObject(json, (typeof(DataTable)));

Create a global variable in TypeScript

globalThis is the future.

First, TypeScript files have two kinds of scopes

global scope

If your file hasn't any import or export line, this file would be executed in global scope that all declaration in it are visible outside this file.

So we would create global variables like this:

// xx.d.ts
declare var age: number

// or 
// xx.ts
// with or without declare keyword
var age: number

// other.ts
globalThis.age = 18 // no error

All magic come from var. Replace var with let or const won't work.

module scope

If your file has any import or export line, this file would be executed within its own scope that we need to extend global by declaration-merging.

// xx[.d].ts
declare global {
  var age: number;
}

// other.ts
globalThis.age = 18 // no error

You can see more about module in official docs

How to check if android checkbox is checked within its onClick method (declared in XML)?

This will do the trick:

  public void itemClicked(View v) {
    if (((CheckBox) v).isChecked()) {
        Toast.makeText(MyAndroidAppActivity.this,
           "Checked", Toast.LENGTH_LONG).show();
    }
  }

How to filter by IP address in Wireshark?

You can also limit the filter to only part of the ip address.

E.G. To filter 123.*.*.* you can use ip.addr == 123.0.0.0/8. Similar effects can be achieved with /16 and /24.

See WireShark man pages (filters) and look for Classless InterDomain Routing (CIDR) notation.

... the number after the slash represents the number of bits used to represent the network.

Install IPA with iTunes 11

For osX Mavericks Users you can install the ipa-file with the Apple Configurator. (Instead of the iPhone configuration utility, which crashes on OSX 10.9)

Preloading images with JavaScript

Try this I think this is better.

var images = [];
function preload() {
    for (var i = 0; i < arguments.length; i++) {
        images[i] = new Image();
        images[i].src = preload.arguments[i];
    }
}

//-- usage --//
preload(
    "http://domain.tld/gallery/image-001.jpg",
    "http://domain.tld/gallery/image-002.jpg",
    "http://domain.tld/gallery/image-003.jpg"
)

Source: http://perishablepress.com/3-ways-preload-images-css-javascript-ajax/

How to force Chrome's script debugger to reload javascript?

It seems as the Chrome debugger loads source files into memory and wont let them go despite of browser cache updates, i.e. it has its own cache apart from the browser cache that is not in sync. At least, this is the case when working with source mapped files (I am debugging typescript sources). After successfully refreshing browser cache and validating that by browsing directly to the source file, you download the updated file, but as soon as you reopen the file in the debugger it will keep returning the old file no matter the version from the ordinary browser cache. Very anoying indeed.

I would consider this a bug in chrome. I use version Version 46.0.2490.71 m.

The only thing that helps, is restarting chrome (close down all chrome browsers).

Can I set an opacity only to the background image of a div?

I implemented Marcus Ekwall's solution but was able to remove a few things to make it simpler and it still works. Maybe 2017 version of html/css?

html:

<div id="content">
  <div id='bg'></div>
  <h2>What is Lorem Ipsum?</h2>
  <p><strong>Lorem Ipsum</strong> is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen
    book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with
    desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
</div>

css:

#content {
  text-align: left;
  width: 75%;
  margin: auto;
  position: relative;
}

#bg {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  background: url('https://static.pexels.com/photos/6644/sea-water-ocean-waves.jpg') center center;
  opacity: .4;
  width: 100%;
  height: 100%;
}

https://jsfiddle.net/abalter/3te9fjL5/

Import Android volley to Android Studio

Way too complicated guys. Just include it in your gradle dependencies:

dependencies {
    ...
    compile 'com.mcxiaoke.volley:library:1.0.17'
}

Omitting the second expression when using the if-else shorthand

If you're not doing the else, why not do:

if (x==2) doSomething();

Servlet for serving static content

try this

<servlet-mapping>
    <servlet-name>default</servlet-name>
    <url-pattern>*.js</url-pattern>
    <url-pattern>*.css</url-pattern>
    <url-pattern>*.ico</url-pattern>
    <url-pattern>*.png</url-pattern>
    <url-pattern>*.jpg</url-pattern>
    <url-pattern>*.htc</url-pattern>
    <url-pattern>*.gif</url-pattern>
</servlet-mapping>    

Edit: This is only valid for the servlet 2.5 spec and up.

Simplest code for array intersection in javascript

"filter" and "indexOf" aren't supported on Array in IE. How about this:

var array1 = [1, 2, 3];
var array2 = [2, 3, 4, 5];

var intersection = [];
for (i in array1) {
    for (j in array2) {
        if (array1[i] == array2[j]) intersection.push(array1[i]);
    }
}

What is the $$hashKey added to my JSON.stringify result

https://www.timcosta.io/angular-js-object-comparisons/

Angular is pretty magical the first time people see it. Automatic DOM updates when you update a variable in your JS, and the same variable will update in your JS file when someone updates its value in the DOM. This same functionality works across page elements, and across controllers.

The key to all of this is the $$hashKey Angular attaches to objects and arrays used in ng-repeats.

This $$hashKey causes a lot of confusion for people who are sending full objects to an API that doesn't strip extra data. The API will return a 400 for all of your requests, but that $$hashKey just wont go away from your objects.

Angular uses the $$hashKey to keep track of which elements in the DOM belong to which item in an array that is being looped through in an ng-repeat. Without the $$hashKey Angular would have no way to apply changes the occur in the JavaScript or DOM to their counterpart, which is one of the main uses for Angular.

Consider this array:

users = [  
    {
         first_name: "Tim"
         last_name: "Costa"
         email: "[email protected]"
    }
]

If we rendered that into a list using ng-repeat="user in users", each object in it would receive a $$hashKey for tracking purposes from Angular. Here are two ways to avoid this $$hashKey.

datetime.parse and making it work with a specific format

Thanks for the tip, i used this to get my date "20071122" parsed, I needed to add datetimestyles, I used none and it worked:

DateTime dt = DateTime.MinValue;

DateTime.TryParseExact("20071122", "yyyyMMdd", null,System.Globalization.DateTimeStyles.None, out dt);

org.hibernate.MappingException: Unknown entity: annotations.Users

Add the following to your xml:

<bean id="sessionFactory"
    class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="packagesToScan">
        <list>
            <value>annotations</value>
        </list>
    </property>
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
            <prop key="hibernate.show_sql">true</prop>
        </props>
    </property>
</bean>

<tx:annotation-driven transaction-manager="transactionManager" />

<bean id="transactionManager"
    class="org.springframework.orm.hibernate4.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

How to create custom view programmatically in swift having controls text field, button etc

The CGRectZero constant is equal to a rectangle at position (0,0) with zero width and height. This is fine to use, and actually preferred, if you use AutoLayout, since AutoLayout will then properly place the view.

But, I expect you do not use AutoLayout. So the most simple solution is to specify the size of the custom view by providing a frame explicitly:

customView = MyCustomView(frame: CGRect(x: 0, y: 0, width: 200, height: 50))
self.view.addSubview(customView)

Note that you also need to use addSubview otherwise your view is not added to the view hierarchy.

How would I access variables from one class to another?

Can you explain why you want to do this?

You're playing around with instance variables/attributes which won't migrate from one class to another (they're bound not even to ClassA, but to a particular instance of ClassA that you created when you wrote ClassA()). If you want to have changes in one class show up in another, you can use class variables:

class ClassA(object):
   var1 = 1
   var2 = 2
   @classmethod
   def method(cls):
       cls.var1 = cls.var1 + cls.var2
       return cls.var1

In this scenario, ClassB will pick up the values on ClassA from inheritance. You can then access the class variables via ClassA.var1, ClassB.var1 or even from an instance ClassA().var1 (provided that you haven't added an instance method var1 which will be resolved before the class variable in attribute lookup.

I'd have to know a little bit more about your particular use case before I know if this is a course of action that I would actually recommend though...

JQuery select2 set default value from an option in list?

One more way - just add a selected = "selected" attribute to the select markup and call select2 on it. It must take your selected value. No need for extra JavaScript. Like this :

Markup

<select class="select2">
   <option id="foo">Some Text</option>
   <option id="bar" selected="selected">Other Text</option>
</select>

JavaScript

$('select').select2(); //oh yes just this!

See fiddle : http://jsfiddle.net/6hZFU/

Edit: (Thanks, Jay Haase!)

If this doesn't work, try setting the val property of select2 to null, to clear the value, like this:

$('select').select2("val", null); //a lil' bit more :)

After this, it is simple enough to set val to "Whatever You Want".

Does Enter key trigger a click event?

@Component({
  selector: 'key-up3',
  template: `
    <input #box (keyup.enter)="doSomething($event)">
    <p>{{values}}</p>
  `
})
export class KeyUpComponent_v3 {
  doSomething(e) {
    alert(e);
  }
}

This works for me!

StringLength vs MaxLength attributes ASP.NET MVC with Entity Framework EF Code First

All good answers...From the validation perspective, I also noticed that MaxLength gets validated at the server side only, while StringLength gets validated at client side too.

Set session variable in laravel

php artisan make:controller SessionController --plain

Then

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Requests;
use App\Http\Controllers\Controller;

class SessionController extends Controller {
   public function accessSessionData(Request $request) {
      if($request->session()->has('my_name'))
         echo $request->session()->get('my_name');
      else
         echo 'No data in the session';
   }
   public function storeSessionData(Request $request) {
      $request->session()->put('my_name','Ajay kumar');
      echo "Data has been added to session";
   }
   public function deleteSessionData(Request $request) {
      $request->session()->forget('my_name');
      echo "Data has been removed from session.";
   }
}
?>

And all route:

Route::get('session/get','SessionController@accessSessionData');
Route::get('session/set','SessionController@storeSessionData');
Route::get('session/remove','SessionController@deleteSessionData');

More Help: How To Set Session In Laravel?

How do I make the scrollbar on a div only visible when necessary?

try

<div style='overflow:auto; width:400px;height:400px;'>here is some text</div>

Extract time from date String

The other answers were good answers when the question was asked. Time moves on, Date and SimpleDateFormat get replaced by newer and better classes and go out of use. In 2017, use the classes in the java.time package:

    String timeString = LocalDateTime.parse(dateString, DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss"))
            .format(DateTimeFormatter.ofPattern("H:mm"));

The result is the desired, 9:00.

How to part DATE and TIME from DATETIME in MySQL

For only date use
date("Y-m-d");

and for only time use
date("H:i:s");

Difference between Fact table and Dimension table?

Dimension table : It is nothing but we can maintains information about the characterized date called as Dimension table.

Example : Time Dimension , Product Dimension.

Fact Table : It is nothing but we can maintains information about the metrics or precalculation data.

Example : Sales Fact, Order Fact.

Star schema : one fact table link with dimension table form as a Start Schema.

enter image description here

Optional Parameters in Go?

No -- neither. Per the Go for C++ programmers docs,

Go does not support function overloading and does not support user defined operators.

I can't find an equally clear statement that optional parameters are unsupported, but they are not supported either.

How do I add items to an array in jQuery?

You are making an ajax request which is asynchronous therefore your console log of the list length occurs before the ajax request has completed.

The only way of achieving what you want is changing the ajax call to be synchronous. You can do this by using the .ajax and passing in asynch : false however this is not recommended as it locks the UI up until the call has returned, if it fails to return the user has to crash out of the browser.

contenteditable change events

_x000D_
_x000D_
const p = document.querySelector('p')_x000D_
const result = document.querySelector('div')_x000D_
const observer = new MutationObserver((mutationRecords) => {_x000D_
  result.textContent = mutationRecords[0].target.data_x000D_
  // result.textContent = p.textContent_x000D_
})_x000D_
observer.observe(p, {_x000D_
  characterData: true,_x000D_
  subtree: true,_x000D_
})
_x000D_
<p contenteditable>abc</p>_x000D_
<div />
_x000D_
_x000D_
_x000D_

Redirect on select option in select box

For someone who doesn't want to use inline JS.

<select data-select-name>
    <option value="">Select...</option>
    <option value="http://google.com">Google</option>
    <option value="http://yahoo.com">Yahoo</option>
</select>
<script type="text/javascript">
    document.addEventListener('DOMContentLoaded',function() {
        document.querySelector('select[data-select-name]').onchange=changeEventHandler;
    },false);

    function changeEventHandler(event) {
        window.location.href = this.options[this.selectedIndex].value;
    }
</script>

How to convert a std::string to const char* or char*?

Use the .c_str() method for const char *.

You can use &mystring[0] to get a char * pointer, but there are a couple of gotcha's: you won't necessarily get a zero terminated string, and you won't be able to change the string's size. You especially have to be careful not to add characters past the end of the string or you'll get a buffer overrun (and probable crash).

There was no guarantee that all of the characters would be part of the same contiguous buffer until C++11, but in practice all known implementations of std::string worked that way anyway; see Does “&s[0]” point to contiguous characters in a std::string?.

Note that many string member functions will reallocate the internal buffer and invalidate any pointers you might have saved. Best to use them immediately and then discard.

How to animate button in android?

import android.view.View;
import android.view.animation.Animation;
import android.view.animation.Transformation;

public class HeightAnimation extends Animation {
    protected final int originalHeight;
    protected final View view;
    protected float perValue;

    public HeightAnimation(View view, int fromHeight, int toHeight) {
        this.view = view;
        this.originalHeight = fromHeight;
        this.perValue = (toHeight - fromHeight);
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        view.getLayoutParams().height = (int) (originalHeight + perValue * interpolatedTime);
        view.requestLayout();
    }

    @Override
    public boolean willChangeBounds() {
        return true;
    }
}

uss to:

HeightAnimation heightAnim = new HeightAnimation(view, view.getHeight(), viewPager.getHeight() - otherView.getHeight());
heightAnim.setDuration(1000);
view.startAnimation(heightAnim);

How do you read scanf until EOF in C?

Man, if you are using Windows, EOF is not reached by pressing enter, but by pressing Crtl+Z at the console. This will print "^Z", an indicator of EOF. The behavior of functions when reading this (the EOF or Crtl+Z):

Function: Output: scanf(...) EOF gets(<variable>) NULL feof(stdin) 1 getchar() EOF

typescript: error TS2693: 'Promise' only refers to a type, but is being used as a value here

If you're using the DefinitelyTyped repository in your project you might be experiencing this recent issue.

A decent workaround you might use (other than waiting for an updated build of the definitions file or refactoring your TS code) is to specify an explicit version+build for the core-js typings rather than let Visual Studio pick the latest/most recent one. I found one that seems to be unaffected by this problem (in my case at least), you can use it replacing the following line from your package.json file:

  "scripts": {
    "postinstall": "typings install dt~core-js --global"
  }

With the following one:

  "scripts": {
    "postinstall": "typings install [email protected]+20161130133742 --global"
  }

This fixed my issue for good. However, is highly recommended to remove the explicit version+build reference as soon as the issue will be released.

For further info regarding this issue, you can also read this blog post that I wrote on the topic.

How do I query for all dates greater than a certain date in SQL Server?

select *  
from dbo.March2010 A 
where A.Date >= Convert(datetime, '2010-04-01' )

In your query, 2010-4-01 is treated as a mathematical expression, so in essence it read

select *  
from dbo.March2010 A 
where A.Date >= 2005; 

(2010 minus 4 minus 1 is 2005 Converting it to a proper datetime, and using single quotes will fix this issue.)

Technically, the parser might allow you to get away with

select *  
from dbo.March2010 A 
where A.Date >= '2010-04-01'

it will do the conversion for you, but in my opinion it is less readable than explicitly converting to a DateTime for the maintenance programmer that will come after you.

'Framework not found' in Xcode

When this error occurred to me was because Pods folder was in iCloud and had no local copy on my computer. Go to your project's folder in Finder and check if there is iCloud's symbol in any of the folders inside it!

Check if string is neither empty nor space in shell script

To check if a string is empty or contains only whitespace you could use:

shopt -s extglob  # more powerful pattern matching

if [ -n "${str##+([[:space:]])}" ]; then
    echo '$str is not null or space'
fi

See Shell Parameter Expansion and Pattern Matching in the Bash Manual.

Calculate logarithm in python

The math.log function is to the base e, i.e. natural logarithm. If you want to the base 10 use math.log10.

SSRS the definition of the report is invalid

The report definition is not valid or supported by this version of Reporting Services. This could be the result of publishing a report definition of a later version of Reporting Services, or that the report definition contains XML that is not well-formed or the XML is not valid based on the Report Definition schema.

I got this error when I used ReportSync to upload some .rdl files to SQL Server Report Services. In my case, the issue was that these .rdl files had some Text Box containing characters like ©, (Em dash), (En dash) characters, etc. When uploading .rdl files using ReportSync, I had to encode these characters (&copy;, &mdash;, &ndash;, etc.) and use Placeholder Properties to set the Markup type to HTML in order to get rid of this error.

I wouldn't get this error If I manually uploaded each of the .rdl files one-by-one using SQL Server Reporting Services. But I have a lot of .rdl files and uploading each one individually would be time-consuming, which is why I use ReportSync to mass upload all .rdl files.

Sorry, if my answer doesn't seem relevant, but I hope this helps anyone else getting this error message when dealing with SSRS .rdl files.

Round up value to nearest whole number in SQL UPDATE

This depends on the database server, but it is often called something like CEIL or CEILING. For example, in MySQL...

mysql> select ceil(10.5);
+------------+
| ceil(10.5) |
+------------+
|         11 | 
+------------+

You can then do UPDATE PRODUCT SET price=CEIL(some_other_field);

How can you tell when a layout has been drawn?

Simply check it by calling post method on your layout or view

 view.post( new Runnable() {
     @Override
     public void run() {
        // your layout is now drawn completely , use it here.
      }
});

Root password inside a Docker container

There are a couple of ways to do it.

  1. To run the Docker overriding the USER setting

     docker exec -u 0 -it containerName bash
    

or

docker exec -u root -it --workdir / <containerName> bash
  1. Make necessary file permissions, etc., during the image build in the Docker file

  2. If all the packages are available in your Linux image, chpasswdin the dockerfile before the USER utility.

For complete reference: http://muralitechblog.com/root-password-of-a-docker-container/

Error - Android resource linking failed (AAPT2 27.0.3 Daemon #0)

com.android.support:support-v4 just recently got update and maybe affect to plugin that use updated version in their dependencies. But if you cannot find in the dependencies (like if you use crosswalk plugin), just put this code in top of your code gradle plugin (no need to add on build.gradle).

configurations.all {
resolutionStrategy.force 'com.android.support:support-v4:24.0.0'
}

Example location to put the code in crosswalk plugin here

Feel free to edit version of com.android.support (DO NOT USE THE 28.0.0) because thats the problem

Fastest way to Remove Duplicate Value from a list<> by lambda

The easiest way to get a new list would be:

List<long> unique = longs.Distinct().ToList();

Is that good enough for you, or do you need to mutate the existing list? The latter is significantly more long-winded.

Note that Distinct() isn't guaranteed to preserve the original order, but in the current implementation it will - and that's the most natural implementation. See my Edulinq blog post about Distinct() for more information.

If you don't need it to be a List<long>, you could just keep it as:

IEnumerable<long> unique = longs.Distinct();

At this point it will go through the de-duping each time you iterate over unique though. Whether that's good or not will depend on your requirements.

Can a WSDL indicate the SOAP version (1.1 or 1.2) of the web service?

Yes you can usually see what SOAP version is supported based on the WSDL.

Take a look at Demo web service WSDL. It has a reference to the soap12 namespace indicating it supports SOAP 1.2. If that was absent then you'd probably be safe assuming the service only supported SOAP 1.1.

Set timeout for webClient.DownloadFile()

My answer comes from here

You can make a derived class, which will set the timeout property of the base WebRequest class:

using System;
using System.Net;

public class WebDownload : WebClient
{
    /// <summary>
    /// Time in milliseconds
    /// </summary>
    public int Timeout { get; set; }

    public WebDownload() : this(60000) { }

    public WebDownload(int timeout)
    {
        this.Timeout = timeout;
    }

    protected override WebRequest GetWebRequest(Uri address)
    {
        var request = base.GetWebRequest(address);
        if (request != null)
        {
            request.Timeout = this.Timeout;
        }
        return request;
    }
}

and you can use it just like the base WebClient class.

How to replace ${} placeholders in a text file?

Use /bin/sh. Create a small shell script that sets the variables, and then parse the template using the shell itself. Like so (edit to handle newlines correctly):

File template.txt:

the number is ${i}
the word is ${word}

File script.sh:

#!/bin/sh

#Set variables
i=1
word="dog"

#Read in template one line at the time, and replace variables (more
#natural (and efficient) way, thanks to Jonathan Leffler).
while read line
do
    eval echo "$line"
done < "./template.txt"

Output:

#sh script.sh
the number is 1
the word is dog

Launch an app from within another (iPhone)

Try the following code will help you to Launch an application from your application

Note: Replace the name fantacy with actual application name

NSString *mystr=[[NSString alloc] initWithFormat:@"fantacy://location?id=1"];
NSURL *myurl=[[NSURL alloc] initWithString:mystr];
[[UIApplication sharedApplication] openURL:myurl];

What does `ValueError: cannot reindex from a duplicate axis` mean?

I came across this error today when I wanted to add a new column like this

df_temp['REMARK_TYPE'] = df.REMARK.apply(lambda v: 1 if str(v)!='nan' else 0)

I wanted to process the REMARK column of df_temp to return 1 or 0. However I typed wrong variable with df. And it returned error like this:

----> 1 df_temp['REMARK_TYPE'] = df.REMARK.apply(lambda v: 1 if str(v)!='nan' else 0)

/usr/lib64/python2.7/site-packages/pandas/core/frame.pyc in __setitem__(self, key, value)
   2417         else:
   2418             # set column
-> 2419             self._set_item(key, value)
   2420 
   2421     def _setitem_slice(self, key, value):

/usr/lib64/python2.7/site-packages/pandas/core/frame.pyc in _set_item(self, key, value)
   2483 
   2484         self._ensure_valid_index(value)
-> 2485         value = self._sanitize_column(key, value)
   2486         NDFrame._set_item(self, key, value)
   2487 

/usr/lib64/python2.7/site-packages/pandas/core/frame.pyc in _sanitize_column(self, key, value, broadcast)
   2633 
   2634         if isinstance(value, Series):
-> 2635             value = reindexer(value)
   2636 
   2637         elif isinstance(value, DataFrame):

/usr/lib64/python2.7/site-packages/pandas/core/frame.pyc in reindexer(value)
   2625                     # duplicate axis
   2626                     if not value.index.is_unique:
-> 2627                         raise e
   2628 
   2629                     # other

ValueError: cannot reindex from a duplicate axis

As you can see it, the right code should be

df_temp['REMARK_TYPE'] = df_temp.REMARK.apply(lambda v: 1 if str(v)!='nan' else 0)

Because df and df_temp have a different number of rows. So it returned ValueError: cannot reindex from a duplicate axis.

Hope you can understand it and my answer can help other people to debug their code.

Error C1083: Cannot open include file: 'stdafx.h'

Add #include "afxwin.h" in your source file. It will solve your issue.

Parser Error when deploy ASP.NET application

Looking at the error message, part of the code of your Default.aspx is :

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="AmeriaTestTask.Default" %>

but AmeriaTestTask.Default does not exists, so you have to change it, most probably to the class defined in Default.aspx.cs. For example for web api aplications, the class defined in Global.asax.cs is : public class WebApiApplication : System.Web.HttpApplication and in the asax page you have :

<%@ Application Codebehind="Global.asax.cs" Inherits="MyProject.WebApiApplication" Language="C#" %>

How to force cp to overwrite without confirmation

you can use this command as well:

cp -ru /zzz/zzz/* /xxx/xxx

it would update your existing file with the newer one though.

How to disable/enable a button with a checkbox if checked

You will have to use javascript, or the JQuery framework to do that. her is an example using Jquery

   $('#toggle').click(function () {
        //check if checkbox is checked
        if ($(this).is(':checked')) {

            $('#sendNewSms').removeAttr('disabled'); //enable input

        } else {
            $('#sendNewSms').attr('disabled', true); //disable input
        }
    });

DEMO: http://jsfiddle.net/T6hvz/

Understanding Linux /proc/id/maps

Each row in /proc/$PID/maps describes a region of contiguous virtual memory in a process or thread. Each row has the following fields:

address           perms offset  dev   inode   pathname
08048000-08056000 r-xp 00000000 03:0c 64593   /usr/sbin/gpm
  • address - This is the starting and ending address of the region in the process's address space
  • permissions - This describes how pages in the region can be accessed. There are four different permissions: read, write, execute, and shared. If read/write/execute are disabled, a - will appear instead of the r/w/x. If a region is not shared, it is private, so a p will appear instead of an s. If the process attempts to access memory in a way that is not permitted, a segmentation fault is generated. Permissions can be changed using the mprotect system call.
  • offset - If the region was mapped from a file (using mmap), this is the offset in the file where the mapping begins. If the memory was not mapped from a file, it's just 0.
  • device - If the region was mapped from a file, this is the major and minor device number (in hex) where the file lives.
  • inode - If the region was mapped from a file, this is the file number.
  • pathname - If the region was mapped from a file, this is the name of the file. This field is blank for anonymous mapped regions. There are also special regions with names like [heap], [stack], or [vdso]. [vdso] stands for virtual dynamic shared object. It's used by system calls to switch to kernel mode. Here's a good article about it: "What is linux-gate.so.1?"

You might notice a lot of anonymous regions. These are usually created by mmap but are not attached to any file. They are used for a lot of miscellaneous things like shared memory or buffers not allocated on the heap. For instance, I think the pthread library uses anonymous mapped regions as stacks for new threads.

JSON character encoding

Also, you can use spring annotation RequestMapping above controller class for receveing application/json;utf-8 in all responses

@Controller
@RequestMapping(produces = {"application/json; charset=UTF-8","*/*;charset=UTF-8"})
public class MyController{
 ...
}

jquery (or pure js) simulate enter key pressed for testing

For those who want to do this in pure javascript, look at:

Using standard KeyboardEvent

As Joe comment it, KeyboardEvent is now the standard.

Same example to fire an enter (keyCode 13):

const ke = new KeyboardEvent('keydown', {
    bubbles: true, cancelable: true, keyCode: 13
});
document.body.dispatchEvent(ke);

You can use this page help you to find the right keyboard event.


Outdated answer:

You can do something like (here for Firefox)

var ev = document.createEvent('KeyboardEvent');
// Send key '13' (= enter)
ev.initKeyEvent(
    'keydown', true, true, window, false, false, false, false, 13, 0);
document.body.dispatchEvent(ev);

Amazon AWS Filezilla transfer permission denied

In my case, after 30 minutes changing permissions, got into account that the XLSX file I was trying to transfer was still open in Excel.

How can I quickly delete a line in VIM starting at the cursor position?

D or dd deletes and copies the line to the register. You can use Vx which only deletes the line and stays in the normal mode.

Pass parameter from a batch file to a PowerShell script

The answer from @Emiliano is excellent. You can also pass named parameters like so:

powershell.exe -Command 'G:\Karan\PowerShell_Scripts\START_DEV.ps1' -NamedParam1 "SomeDataA" -NamedParam2 "SomeData2"

Note the parameters are outside the command call, and you'll use:

[parameter(Mandatory=$false)]
  [string]$NamedParam1,
[parameter(Mandatory=$false)]
  [string]$NamedParam2

Plot a horizontal line using matplotlib

You are correct, I think the [0,len(xs)] is throwing you off. You'll want to reuse the original x-axis variable xs and plot that with another numpy array of the same length that has your variable in it.

annual = np.arange(1,21,1)
l = np.array(value_list) # a list with 20 values
spl = UnivariateSpline(annual,l)
xs = np.linspace(1,21,200)
plt.plot(xs,spl(xs),'b')

#####horizontal line
horiz_line_data = np.array([40 for i in xrange(len(xs))])
plt.plot(xs, horiz_line_data, 'r--') 
###########plt.plot([0,len(xs)],[40,40],'r--',lw=2)
pylab.ylim([0,200])
plt.show()

Hopefully that fixes the problem!

Safest way to get last record ID from a table

Safest way will be to output or return the scope_identity() within the procedure inserting the row, and then retrieve the row based on that ID. Use of @@Identity is to be avoided since you can get the incorrect ID when triggers are in play.

Any technique of asking for the maximum value / top 1 suffers a race condition where 2 people adding at the same time, would then get the same ID back when they looked for the highest ID.

int to unsigned int conversion

You can convert an int to an unsigned int. The conversion is valid and well-defined.

Since the value is negative, UINT_MAX + 1 is added to it so that the value is a valid unsigned quantity. (Technically, 2N is added to it, where N is the number of bits used to represent the unsigned type.)

In this case, since int on your platform has a width of 32 bits, 62 is subtracted from 232, yielding 4,294,967,234.

how to get all child list from Firebase android

your problem is why your code doesn't work.

this your code:

Firebase ref = new Firebase(FIREBASE_URL);

  ref.addValueEventListener(new ValueEventListener() {
      @Override
      public void onDataChange(DataSnapshot snapshot) {
          Log.e("Count " ,""+snapshot.getChildrenCount());
          for (DataSnapshot postSnapshot: snapshot.getChildren()) {
            <YourClass> post = postSnapshot.getValue(<YourClass>.class);
            Log.e("Get Data", post.<YourMethod>());
          }
      }
      @Override
      public void onCancelled(FirebaseError firebaseError) {
          Log.e("The read failed: " ,firebaseError.getMessage());
      }
  })

you miss the simplest thing: getChildren()

FirebaseDatabase db = FirebaseDatabase.getInstance();
DatabaseReference reference = FirebaseAuth.getInstance().getReference("Donald Trump");

reference.addValueEventListener(new ValueEventListener() {
   @Override
   public void onDataChange(DataSnapshot dataSnapshot) {

            int count = (int) dataSnapshot.getChildrenCount(); // retrieve number of childrens under Donald Trump

            String[] hairColors = new String[count];

            index = 0;
            for (DataSnapshot datas : dataSnapshot.getChildren()){

                hairColors[index] = datas.getValue(String.class);

            }
            index ++

            for (int i = 0; i < count; i++)
            Toast(MainActivity.this, "hairColors : " + hairColors[i], toast.LENGTH_SHORT).show();

            }

    }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }

    });

Sublime Text 3 how to change the font size of the file sidebar?

You need to change it at "class": "sidebar_label" Example, in your .sublime-theme file:

// Sidebar entry
{
    "class": "sidebar_label",
    "color": [212, 212, 213],
    "shadow_offset": [0, 0],
    "font.size":13
}

Credit

Sending a JSON to server and retrieving a JSON in return, without JQuery

Using new api fetch:

_x000D_
_x000D_
const dataToSend = JSON.stringify({"email": "[email protected]", "password": "101010"});
let dataReceived = ""; 
fetch("", {
    credentials: "same-origin",
    mode: "same-origin",
    method: "post",
    headers: { "Content-Type": "application/json" },
    body: dataToSend
})
    .then(resp => {
        if (resp.status === 200) {
            return resp.json()
        } else {
            console.log("Status: " + resp.status)
            return Promise.reject("server")
        }
    })
    .then(dataJson => {
        dataReceived = JSON.parse(dataJson)
    })
    .catch(err => {
        if (err === "server") return
        console.log(err)
    })

console.log(`Received: ${dataReceived}`)                
_x000D_
_x000D_
_x000D_ You need to handle when server sends other status rather than 200(ok), you should reject that result because if you were to left it in blank, it will try to parse the json but there isn't, so it will throw an error

How to compare 2 files fast using .NET?

If the files are not too big, you can use:

public static byte[] ComputeFileHash(string fileName)
{
    using (var stream = File.OpenRead(fileName))
        return System.Security.Cryptography.MD5.Create().ComputeHash(stream);
}

It will only be feasible to compare hashes if the hashes are useful to store.

(Edited the code to something much cleaner.)

Styling a input type=number

The css to modify the spinner arrows is obtuse and unreliable cross-browser.

The most stable option I have found, is to absolutely position an image with pointer-events: none; on top of the spinners.

Untested in Edge but works in all other browsers.

PHPExcel set border and format for all sheets in spreadsheet

To answer your extra question:

You can set which rows should be repeated on every page using:

$objPHPExcel->getActiveSheet()->getPageSetup()->setRowsToRepeatAtTopByStartAndEnd(1, 5);

Now, row 1, 2, 3, 4 and 5 will be repeated.

Laravel 5 call a model function in a blade view

I ran into a similar issue where I wanted to call a function defined in my controller from my view. Although it perplexed me for a while trying to figure out how to get to the controller from the view it turned out to be fairly straightforward.

I hand off an array to my views with data records that the view formats and presents to the user with jQuery DataTables (big duh). One column in the presented UI table is a set of action buttons that need to be created per row based on the content of the data in each of the rows. I guess I could have added the button definitions to the data rows as a column sent to the views but not all views needed the buttons so why? Instead, I wanted the view that needed them add them.

In the controller I pass a reference to the controller itself to the view as in

->with('callbackController', $this)

I called it callbackController as that is what I was doing. Now, inside my view I can either escape to PHP to use $callbackController to access the parent controller as in

<?php echo $callbackController->makeButtons($parameters); ?>

or just use the Blade mechanism

{!! $callbackController->makeButtons($parameters); ?>

It seems to be working fine across multiple controllers and views. I have not noticed a performance penalty using this mechanism and I have one huge table with over 50K rows.

I have not tried to pass on references to other objects (e.g., models, etc) yet but I do not see what that would not work as well

Might not be elegant but it seems to get the job done.

What is the problem with shadowing names defined in outer scopes?

data = [4, 5, 6] # Your global variable

def print_data(data): # <-- Pass in a parameter called "data"
    print data  # <-- Note: You can access global variable inside your function, BUT for now, which is which? the parameter or the global variable? Confused, huh?

print_data(data)

PHPUnit assert that an exception was thrown?

Comprehensive Solution

PHPUnit's current "best practices" for exception testing seem.. lackluster (docs).

Since I wanted more than the current expectException implementation, I made a trait to use on my test cases. It's only ~50 lines of code.

  • Supports multiple exceptions per test
  • Supports assertions called after the exception is thrown
  • Robust and clear usage examples
  • Standard assert syntax
  • Supports assertions for more than just message, code, and class
  • Supports inverse assertion, assertNotThrows
  • Supports PHP 7 Throwable errors

Library

I published the AssertThrows trait to Github and packagist so it can be installed with composer.

Simple Example

Just to illustrate the spirit behind the syntax:

<?php

// Using simple callback
$this->assertThrows(MyException::class, [$obj, 'doSomethingBad']);

// Using anonymous function
$this->assertThrows(MyException::class, function() use ($obj) {
    $obj->doSomethingBad();
});

Pretty neat?


Full Usage Example

Please see below for a more comprehensive usage example:

<?php

declare(strict_types=1);

use Jchook\AssertThrows\AssertThrows;
use PHPUnit\Framework\TestCase;

// These are just for illustration
use MyNamespace\MyException;
use MyNamespace\MyObject;

final class MyTest extends TestCase
{
    use AssertThrows; // <--- adds the assertThrows method

    public function testMyObject()
    {
        $obj = new MyObject();

        // Test a basic exception is thrown
        $this->assertThrows(MyException::class, function() use ($obj) {
            $obj->doSomethingBad();
        });

        // Test custom aspects of a custom extension class
        $this->assertThrows(MyException::class, 
            function() use ($obj) {
                $obj->doSomethingBad();
            },
            function($exception) {
                $this->assertEquals('Expected value', $exception->getCustomThing());
                $this->assertEquals(123, $exception->getCode());
            }
        );

        // Test that a specific exception is NOT thrown
        $this->assertNotThrows(MyException::class, function() use ($obj) {
            $obj->doSomethingGood();
        });
    }
}

?>

What are the differences between a program and an application?

When I studied IT in college my prof. made it simple for me:

"A computer "program" and an "application" (a.k.a. 'app') are one-in-the-same. The only difference is a technical one. While both are the same, an 'application' is a computer program launched and dependent upon an operating system to execute."

Got it right on the exam.

So when you click on a word processor, for example, it is an application, as is that hidden file that runs the printer spooler launched only by the OS. The two programs depend on the OS, whereby the OS itself or your internal BIOS programming are not 'apps' in the technical sense as they communicate directly with the computer hardware itself.

Unless the definition has changed in the past few years, commercial entities like Microsoft and Apple are not using the terms properly, preferring sexy marketing by making the term 'apps' seem like something popular market and 'new', because a "computer program" sounds too 'nerdy'. :(

How can I upgrade NumPy?

If you don't encounter any permission errors with

pip install -U numpy

try:

pip install --user -U numpy

iOS 7 App Icons, Launch images And Naming Convention While Keeping iOS 6 Icons

In case you do not want to use Asset Catalog, you can add an iOS 7 icon for an old app by creating a 120x120 .png image. Name it Icon-120.png and drag in to the project.

Under TARGET > Your App > Info > Icon files, add one more entry in the Target Properties:

enter image description here

I tested on Xcode 5 and an app was submitted without the missing retina icon warning.

What encoding/code page is cmd.exe using?

I've been frustrated for long by Windows code page issues, and the C programs portability and localisation issues they cause. The previous posts have detailed the issues at length, so I'm not going to add anything in this respect.

To make a long story short, eventually I ended up writing my own UTF-8 compatibility library layer over the Visual C++ standard C library. Basically this library ensures that a standard C program works right, in any code page, using UTF-8 internally.

This library, called MsvcLibX, is available as open source at https://github.com/JFLarvoire/SysToolsLib. Main features:

  • C sources encoded in UTF-8, using normal char[] C strings, and standard C library APIs.
  • In any code page, everything is processed internally as UTF-8 in your code, including the main() routine argv[], with standard input and output automatically converted to the right code page.
  • All stdio.h file functions support UTF-8 pathnames > 260 characters, up to 64 KBytes actually.
  • The same sources can compile and link successfully in Windows using Visual C++ and MsvcLibX and Visual C++ C library, and in Linux using gcc and Linux standard C library, with no need for #ifdef ... #endif blocks.
  • Adds include files common in Linux, but missing in Visual C++. Ex: unistd.h
  • Adds missing functions, like those for directory I/O, symbolic link management, etc, all with UTF-8 support of course :-).

More details in the MsvcLibX README on GitHub, including how to build the library and use it in your own programs.

The release section in the above GitHub repository provides several programs using this MsvcLibX library, that will show its capabilities. Ex: Try my which.exe tool with directories with non-ASCII names in the PATH, searching for programs with non-ASCII names, and changing code pages.

Another useful tool there is the conv.exe program. This program can easily convert a data stream from any code page to any other. Its default is input in the Windows code page, and output in the current console code page. This allows to correctly view data generated by Windows GUI apps (ex: Notepad) in a command console, with a simple command like: type WINFILE.txt | conv

This MsvcLibX library is by no means complete, and contributions for improving it are welcome!

how to draw directed graphs using networkx in python?

I only put this in for completeness. I've learned plenty from marius and mdml. Here are the edge weights. Sorry about the arrows. Looks like I'm not the only one saying it can't be helped. I couldn't render this with ipython notebook I had to go straight from python which was the problem with getting my edge weights in sooner.

import networkx as nx
import numpy as np
import matplotlib.pyplot as plt
import pylab

G = nx.DiGraph()

G.add_edges_from([('A', 'B'),('C','D'),('G','D')], weight=1)
G.add_edges_from([('D','A'),('D','E'),('B','D'),('D','E')], weight=2)
G.add_edges_from([('B','C'),('E','F')], weight=3)
G.add_edges_from([('C','F')], weight=4)


val_map = {'A': 1.0,
                   'D': 0.5714285714285714,
                              'H': 0.0}

values = [val_map.get(node, 0.45) for node in G.nodes()]
edge_labels=dict([((u,v,),d['weight'])
                 for u,v,d in G.edges(data=True)])
red_edges = [('C','D'),('D','A')]
edge_colors = ['black' if not edge in red_edges else 'red' for edge in G.edges()]

pos=nx.spring_layout(G)
nx.draw_networkx_edge_labels(G,pos,edge_labels=edge_labels)
nx.draw(G,pos, node_color = values, node_size=1500,edge_color=edge_colors,edge_cmap=plt.cm.Reds)
pylab.show()

enter image description here

How to write a confusion matrix in Python?

In a general sense, you're going to need to change your probability array. Instead of having one number for each instance and classifying based on whether or not it is greater than 0.5, you're going to need a list of scores (one for each class), then take the largest of the scores as the class that was chosen (a.k.a. argmax).

You could use a dictionary to hold the probabilities for each classification:

prob_arr = [{classification_id: probability}, ...]

Choosing a classification would be something like:

for instance_scores in prob_arr :
    predicted_classes = [cls for (cls, score) in instance_scores.iteritems() if score = max(instance_scores.values())]

This handles the case where two classes have the same scores. You can get one score, by choosing the first one in that list, but how you handle that depends on what you're classifying.

Once you have your list of predicted classes and a list of expected classes you can use code like Torsten Marek's to create the confusion array and calculate the accuracy.

PHP regular expressions: No ending delimiter '^' found in

PHP regex strings need delimiters. Try:

$numpattern="/^([0-9]+)$/";

Also, note that you have a lower case o, not a zero. In addition, if you're just validating, you don't need the capturing group, and can simplify the regex to /^\d+$/.

Example: http://ideone.com/Ec3zh

See also: PHP - Delimiters

How do I convert from int to Long in Java?

 1,new Long(intValue);
 2,Long.valueOf(intValue);

What is N-Tier architecture?

If I understand the question, then it seems to me that the questioner is really asking "OK, so 3-tier is well understood, but it seems that there's a mix of hype, confusion, and uncertainty around what 4-tier, or to generalize, N-tier architectures mean. So...what's a definition of N-tier that is widely understood and agreed upon?"

It's actually a fairly deep question, and to explain why, I need to go a little deeper. Bear with me.

The classic 3-tier architecture: database, "business logic" and presentation, is a good way to clarify how to honor the principle of separation of concerns. Which is to say, if I want to change how "the business" wants to service customers, I should not have to look through the entire system to figure out how to do this, and in particular, decisions business issues shouldn't be scattered willy-nilly through the code.

Now, this model served well for decades, and it is the classic 'client-server' model. Fast forward to cloud offerings, where web browsers are the user interface for a broad and physically distributed set of users, and one typically ends up having to add content distribution services, which aren't a part of the classic 3-tier architecture (and which need to be managed in their own right).

The concept generalizes when it comes to services, micro-services, how data and computation are distributed and so on. Whether or not something is a 'tier' largely comes down to whether or not the tier provides an interface and deployment model to services that are behind (or beneath) the tier. So a content distribution network would be a tier, but an authentication service would not be.

Now, go and read other descriptions of examples of N-tier architectures with this concept in mind, and you will begin to understand the issue. Other perspectives include vendor-based approaches (e.g. NGINX), content-aware load balancers, data isolation and security services (e.g. IBM Datapower), all of which may or may not add value to a given architecture, deployment, and use cases.

iOS: How to store username/password within an app?

try this one:

 KeychainItemWrapper *keychainItem = [[KeychainItemWrapper alloc] initWithIdentifier:@"YourAppLogin" accessGroup:nil];
[keychainItem setObject:@"password you are saving" forKey:kSecValueData]; 
[keychainItem setObject:@"username you are saving" forKey:kSecAttrAccount];

may it will help.

Add custom message to thrown exception while maintaining stack trace in Java

Exceptions are usually immutable: you can't change their message after they've been created. What you can do, though, is chain exceptions:

throw new TransactionProblemException(transNbr, originalException);

The stack trace will look like

TransactionProblemException : transNbr
at ...
at ...
caused by OriginalException ...
at ...
at ...

How to clear an EditText on click?

Are you looking for behavior similar to the x that shows up on the right side of text fields on an iphone that clears the text when tapped? It's called clearButtonMode there. Here is how to create that same functionality in an Android EditText view:

String value = "";//any text you are pre-filling in the EditText

final EditText et = new EditText(this);
et.setText(value);
final Drawable x = getResources().getDrawable(R.drawable.presence_offline);//your x image, this one from standard android images looks pretty good actually
x.setBounds(0, 0, x.getIntrinsicWidth(), x.getIntrinsicHeight());
et.setCompoundDrawables(null, null, value.equals("") ? null : x, null);
et.setOnTouchListener(new OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (et.getCompoundDrawables()[2] == null) {
            return false;
        }
        if (event.getAction() != MotionEvent.ACTION_UP) {
            return false;
        }
        if (event.getX() > et.getWidth() - et.getPaddingRight() - x.getIntrinsicWidth()) {
            et.setText("");
            et.setCompoundDrawables(null, null, null, null);
        }
        return false;
    }
});
et.addTextChangedListener(new TextWatcher() {
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        et.setCompoundDrawables(null, null, et.getText().toString().equals("") ? null : x, null);
    }

    @Override
    public void afterTextChanged(Editable arg0) {
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    }
});

Mean filter for smoothing images in Matlab

I see good answers have already been given, but I thought it might be nice to just give a way to perform mean filtering in MATLAB using no special functions or toolboxes. This is also very good for understanding exactly how the process works as you are required to explicitly set the convolution kernel. The mean filter kernel is fortunately very easy:

I = imread(...)
kernel = ones(3, 3) / 9; % 3x3 mean kernel
J = conv2(I, kernel, 'same'); % Convolve keeping size of I

Note that for colour images you would have to apply this to each of the channels in the image.

Using a string variable as a variable name

You will be much happier using a dictionary instead:

my_data = {}
foo = "hello"
my_data[foo] = "goodbye"
assert my_data["hello"] == "goodbye"

Android Color Picker

Here's another library:

https://github.com/eltos/SimpleDialogFragments

Features color wheel and pallet picker dialogs

Center a column using Twitter Bootstrap 3

There are two approaches to centering a column <div> in Bootstrap 3:

Approach 1 (offsets):

The first approach uses Bootstrap's own offset classes so it requires no change in markup and no extra CSS. The key is to set an offset equal to half of the remaining size of the row. So for example, a column of size 2 would be centered by adding an offset of 5, that's (12-2)/2.

In markup this would look like:

<div class="row">
    <div class="col-md-2 col-md-offset-5"></div>
</div>

Now, there's an obvious drawback for this method. It only works for even column sizes, so only .col-X-2, .col-X-4, col-X-6, col-X-8, and col-X-10 are supported.


Approach 2 (the old margin:auto)

You can center any column size by using the proven margin: 0 auto; technique. You just need to take care of the floating that is added by Bootstrap's grid system. I recommend defining a custom CSS class like the following:

.col-centered{
    float: none;
    margin: 0 auto;
}

Now you can add it to any column size at any screen size, and it will work seamlessly with Bootstrap's responsive layout:

<div class="row">
    <div class="col-lg-1 col-centered"></div>
</div>

Note: With both techniques you could skip the .row element and have the column centered inside a .container, but you would notice a minimal difference in the actual column size because of the padding in the container class.


Update:

Since v3.0.1 Bootstrap has a built-in class named center-block that uses margin: 0 auto, but is missing float:none, you can add that to your CSS to make it work with the grid system.

AngularJS : Clear $watch

If you have too much watchers and you need to clear all of them, you can push them into an array and destroy every $watch in a loop.

var watchers = [];
watchers.push( $scope.$watch('watch-xxx', function(newVal){
   //do something
}));    

for(var i = 0; i < watchers.length; ++i){
    if(typeof watchers[i] === 'function'){
        watchers[i]();
    }
}

watchers = [];

Formatting DataBinder.Eval data

Why not use the simpler syntax?

<asp:Label id="lblNewsDate" runat="server" Text='<%# Eval("publishedDate", "{0:dddd d MMMM}") %>'</label>

This is the template control "Eval" that takes in the expression and the string format:

protected internal string Eval(
string expression,
string format

)

http://msdn.microsoft.com/en-us/library/3d2sz789.aspx

What are the different types of indexes, what are the benefits of each?

Different database systems have different names for the same type of index, so be careful with this. For example, what SQL Server and Sybase call "clustered index" is called in Oracle an "index-organised table".

Validating Phone Numbers Using Javascript

To validate Phone number using regular expression in java script.

In india phone is 10 digit and starting digits are 6,7,8 and 9.

Javascript and HTML code:

_x000D_
_x000D_
function validate()
{
  var text = document.getElementById("pno").value;
  var regx = /^[6-9]\d{9}$/ ;
  if(regx.test(text))
    alert("valid");
  else
    alert("invalid");
}
_x000D_
<html>
    <head>
        <title>JS compiler - knox97</title>
  </head>
  <body>
  <input id="pno" placeholder="phonenumber" type="tel" maxlength="10" > 
    </br></br>
    <button onclick="validate()" type="button">submit</button>
  </body>
</html>
_x000D_
_x000D_
_x000D_

How to display hexadecimal numbers in C?

Try:

printf("%04x",a);
  • 0 - Left-pads the number with zeroes (0) instead of spaces, where padding is specified.
  • 4 (width) - Minimum number of characters to be printed. If the value to be printed is shorter than this number, the result is right justified within this width by padding on the left with the pad character. By default this is a blank space, but the leading zero we used specifies a zero as the pad char. The value is not truncated even if the result is larger.
  • x - Specifier for hexadecimal integer.

More here

Sample random rows in dataframe

You could do this:

sample_data = data[sample(nrow(data), sample_size, replace = FALSE), ]

How do I get the unix timestamp in C as an int?

#include <stdio.h>
#include <time.h>

int main ()
{
   time_t seconds;

   seconds = time(NULL);
   printf("Seconds since January 1, 1970 = %ld\n", seconds);

   return(0);
}

And will get similar result:
Seconds since January 1, 1970 = 1476107865

What happens when a duplicate key is put into a HashMap?

Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced.

Cannot use string offset as an array in php

I believe what are you asking about is a variable interpolation in PHP.

Let's do a simple fixture:

$obj = (object) array('foo' => array('bar'), 'property' => 'value');
$var = 'foo';

Now we have an object, where:

print_r($obj);

Will give output:

stdClass Object
    (
        [foo] => Array
            (
                [0] => bar
            )

        [property] => value
    )

And we have variable $var containing string "foo".

If you'll try to use:

$give_me_foo = $obj->$var[0];

Instead of:

$give_me_foo = $obj->foo[0];

You get "Cannot use string offset as an array [...]" error message as a result, because what you are trying to do, is in fact sending message $var[0] to object $obj. And - as you can see from fixture - there is no content of $var[0] defined. Variable $var is a string and not an array.

What you can do in this case is to use curly braces, which will assure that at first is called content of $var, and subsequently the rest of message-sent:

$give_me_foo = $obj->{$var}[0];

The result is "bar", as you would expect.

Adding a caption to an equation in LaTeX

You may want to look at http://tug.ctan.org/tex-archive/macros/latex/contrib/float/ which allows you to define new floats using \newfloat

I say this because captions are usually applied to floats.

Straight ahead equations (those written with $ ... $, $$ ... $$, begin{equation}...) are in-line objects that do not support \caption.

This can be done using the following snippet just before \begin{document}

\usepackage{float}
\usepackage{aliascnt}
\newaliascnt{eqfloat}{equation}
\newfloat{eqfloat}{h}{eqflts}
\floatname{eqfloat}{Equation}

\newcommand*{\ORGeqfloat}{}
\let\ORGeqfloat\eqfloat
\def\eqfloat{%
  \let\ORIGINALcaption\caption
  \def\caption{%
    \addtocounter{equation}{-1}%
    \ORIGINALcaption
  }%
  \ORGeqfloat
}

and when adding an equation use something like

\begin{eqfloat}
\begin{equation}
f( x ) = ax + b
\label{eq:linear}
\end{equation}
\caption{Caption goes here}
\end{eqfloat}

Create array of regex matches

        Set<String> keyList = new HashSet();
        Pattern regex = Pattern.compile("#\\{(.*?)\\}");
        Matcher matcher = regex.matcher("Content goes here");
        while(matcher.find()) {
            keyList.add(matcher.group(1)); 
        }
        return keyList;

What precisely does 'Run as administrator' do?

A little clearer... A software program that has kernel mode access has total access to all of the computer's data and its hardware.

Since Windows Vista Microsoft has stopped any and all I/O processes from accessing the kernel (ring 0) directly ever again. The closest we get is a folder created as a virtual kernel access partition, but technically no access to kernel itself; the kernel meets halfway.

This is because the software itself dictates which token to use, so if it asks for an administrator access token, instead of just allowing communications with the kernel like on Windows XP you are prompted to allow access to the kernel, each and every time. Changing UAC could reduce prompts, but never the kernel prompts.

Even when you login as an Administrator, you are running processes as a standard user until prompted to elevate the rights you have. I believe logged in as the administrator saves you from entering the credentials. But it also writes to the administrator users folder structure.

Kernel access is similar to root access in Linux. When you elevate your permissions you are isolating yourself from the root of C:\ and whatever lovely environment variables are contained within.

If you remember BSODs this was the OS shutting down when it believed a bad I/O reached the kernel.

Troubleshooting "program does not contain a static 'Main' method" when it clearly does...?

That's odd. Does your program compile and run successfully and only fail on 'Publish' or does it fail on every compile now?

Also, have you perhaps changed the file's properties' Build Action to something other than Compile?

Postgresql: password authentication failed for user "postgres"

The response of staff is correct, but if you want to further automate can do:

$ sudo -u postgres psql -c "ALTER USER postgres PASSWORD 'postgres';"

Done! You saved User = postgres and password = postgres.

If you do not have a password for the User postgres ubuntu do:

$ sudo passwd postgres

Trying to fire the onload event on script tag

You should set the src attribute after the onload event, f.ex:

el.onload = function() { //...
el.src = script;

You should also append the script to the DOM before attaching the onload event:

$body.append(el);
el.onload = function() { //...
el.src = script;

Remember that you need to check readystate for IE support. If you are using jQuery, you can also try the getScript() method: http://api.jquery.com/jQuery.getScript/

ORA-12528: TNS Listener: all appropriate instances are blocking new connections. Instance "CLRExtProc", status UNKNOWN

I had this error message with boot2docker on windows with the docker-oracle-xe-11g image (https://registry.hub.docker.com/u/wnameless/oracle-xe-11g/).

The reason was that the virtual box disk was full (check with boot2docker.exe ssh df). Deleting old images and restarting the container solved the problem.

Check if a string is html or not

A little bit of validation with:

/<(?=.*? .*?\/ ?>|br|hr|input|!--|wbr)[a-z]+.*?>|<([a-z]+).*?<\/\1>/i.test(htmlStringHere) 

This searches for empty tags (some predefined) and / terminated XHTML empty tags and validates as HTML because of the empty tag OR will capture the tag name and attempt to find it's closing tag somewhere in the string to validate as HTML.

Explained demo: http://regex101.com/r/cX0eP2

Update:

Complete validation with:

/<(br|basefont|hr|input|source|frame|param|area|meta|!--|col|link|option|base|img|wbr|!DOCTYPE).*?>|<(a|abbr|acronym|address|applet|article|aside|audio|b|bdi|bdo|big|blockquote|body|button|canvas|caption|center|cite|code|colgroup|command|datalist|dd|del|details|dfn|dialog|dir|div|dl|dt|em|embed|fieldset|figcaption|figure|font|footer|form|frameset|head|header|hgroup|h1|h2|h3|h4|h5|h6|html|i|iframe|ins|kbd|keygen|label|legend|li|map|mark|menu|meter|nav|noframes|noscript|object|ol|optgroup|output|p|pre|progress|q|rp|rt|ruby|s|samp|script|section|select|small|span|strike|strong|style|sub|summary|sup|table|tbody|td|textarea|tfoot|th|thead|time|title|tr|track|tt|u|ul|var|video).*?<\/\2>/i.test(htmlStringHere) 

This does proper validation as it contains ALL HTML tags, empty ones first followed by the rest which need a closing tag.

Explained demo here: http://regex101.com/r/pE1mT5

Passing environment-dependent variables in webpack

Just another option, if you want to use only a cli interface, just use the define option of webpack. I add the following script in my package.json :

"build-production": "webpack -p --define process.env.NODE_ENV='\"production\"' --progress --colors"

So I just have to run npm run build-production.

How do I calculate the normal vector of a line segment?

If we define dx = x2 - x1 and dy = y2 - y1, then the normals are (-dy, dx) and (dy, -dx).

Note that no division is required, and so you're not risking dividing by zero.

How to call a Parent Class's method from Child Class in Python?

class a(object):
    def my_hello(self):
        print "hello ravi"

class b(a):
    def my_hello(self):
    super(b,self).my_hello()
    print "hi"

obj = b()
obj.my_hello()