How can I change a file's encoding with vim?

While using vim to do it is perfectly possible, why don't you simply use iconv? I mean - loading text editor just to do encoding conversion seems like using too big hammer for too small nail.

Just:

iconv -f utf-16 -t utf-8 file.xml > file.utf8.xml

And you're done.

How to find a user's home directory on linux or unix?

Find a Java wrapper for getpwuid/getpwnam(3) functions, they ask the system for user information by uid or by login name and you get back all info including the default home directory.

How do I rename the android package name?

Goto your AndroidManifest.xml.
place your cursor in the package name like shown below don't select it just place it.

Then press shift+F6 you will get a popup window as shown below select Rename package.

Enter your new name and select Refactor. (Note since my cursor is on "something" only something is renamed.)

That's it done.

Running an outside program (executable) in Python?

The simplest way is:

import os
os.startfile("C:\Documents and Settings\flow_model\flow.exe")

It works; I tried it.

Calling Javascript from a html form

Everything seems to be perfect in your code except the fact that handleClick() isn't working because this function lacks a parameter in its function call invocation(but the function definition within has an argument which makes a function mismatch to occur).

The following is a sample working code for calculating all semester's total marks and corresponding grade. It demonstrates the use of a JavaScript function(call) within a html file and also solves the problem you are facing.

<!DOCTYPE html>
<html>
<head>
    <title> Semester Results </title>
</head>
<body>
    <h1> Semester Marks </h1> <br> 
    <script type = "text/javascript">
        function checkMarks(total)
        {
            document.write("<h1> Final Result !!! </h1><br>");
            document.write("Total Marks = " + total + "<br><br>");
            var avg = total / 6.0;
            document.write("CGPA = " + (avg / 10.0).toFixed(2) + "<br><br>");
            if(avg >= 90)
                document.write("Grade = A");
            else if(avg >= 80)
                document.write("Grade = B");
            else if(avg >= 70)
                document.write("Grade = C");
            else if(avg >= 60)
                document.write("Grade = D");
            else if(avg >= 50)
                document.write("Grade = Pass");
            else
                document.write("Grade = Fail");
       }
    </script>
    <form name = "myform" action = "javascript:checkMarks(Number(s1.value) + Number(s2.value) + Number(s3.value) + Number(s4.value) + Number(s5.value) + Number(s6.value))"/>
        Semester 1:  <input type = "text" id = "s1"/> <br><br>
        Semester 2:  <input type = "text" id = "s2"/> <br><br>
        Semester 3:  <input type = "text" id = "s3"/> <br><br>
        Semester 4:  <input type = "text" id = "s4"/> <br><br>
        Semester 5:  <input type = "text" id = "s5"/> <br><br>
        Semester 6:  <input type = "text" id = "s6"/> <br><br><br>
        <input type = "submit" value = "Submit"/>
    </form>
</body>
</html>

Access is denied when attaching a database

Add permission to the folder where your .mdf file is.

Check this name: NT Service\MSSQLSERVER

And change the Location to your server name.

What linux shell command returns a part of a string?

${string:position:length}

How do I install boto?

If you already have boto installed in one python version and then install a higher python version, boto is not found by the new version of python.

For example, I had python2.7 and then installed python3.5 (keeping both). My script under python3.5 could not find boto. Doing "pip install boto" told me that boto was already installed in /usr/lib/python2.7/dist-packages.

So I did

pip install --target /usr/lib/python3.5/dist-packages boto

This allowed my script under python3.5 to find boto.

C char* to int conversion

atoi can do that for you

Example:

char string[] = "1234";
int sum = atoi( string );
printf("Sum = %d\n", sum ); // Outputs: Sum = 1234

How to efficiently calculate a running standard deviation?

The basic answer is to accumulate the sum of both x (call it 'sum_x1') and x² (call it 'sum_x2') as you go. The value of the standard deviation is then:

stdev = sqrt((sum_x2 / n) - (mean * mean))

where

mean = sum_x / n

This is the sample standard deviation; you get the population standard deviation using 'n' instead of 'n - 1' as the divisor.

You may need to worry about the numerical stability of taking the difference between two large numbers if you are dealing with large samples. Go to the external references in other answers (Wikipedia, etc) for more information.

Formatting a double to two decimal places

The problem is that when you are doing additions and multiplications of numbers all with two decimal places, you expect there will be no rounding errors, but remember the internal representation of double is in base 2, not in base 10 ! So a number like 0.1 in base 10 may be in base 2 : 0.101010101010110011... with an infinite number of decimals (the value stored in the double will be a number N with :

 0.1-Math.Pow(2,-64) < N < 0.1+Math.Pow(2,-64)

As a consequence an operation like 12.3 + 0.1 may be not the same exact 64 bits double value as 12.4 (or 12.456 * 10 may be not the same as 124.56) because of rounding errors. For example if you store in a Database the result of 12.3 +0.1 into a table/column field of type double precision number and then SELECT WHERE xx=12.4 you may realize that you stored a number that is not exactly 12.4 and the Sql select will not return the record; So if you cannot use the decimal datatype (which has internal representation in base 10) and must use the 'double' datatype, you have to do some normalization after each addition or multiplication :

double freqMHz= freqkHz.MulRound(0.001); // freqkHz*0.001
double amountEuro= amountEuro.AddRound(delta); // amountEuro+delta


    public static double AddRound(this double d,double val)
    {
        return double.Parse(string.Format("{0:g14}", d+val));
    }
    public static double MulRound(this double d,double val)
    {
        return double.Parse(string.Format("{0:g14}", d*val));
    }

from list of integers, get number closest to a given value

It's important to note that Lauritz's suggestion idea of using bisect does not actually find the closest value in MyList to MyNumber. Instead, bisect finds the next value in order after MyNumber in MyList. So in OP's case you'd actually get the position of 44 returned instead of the position of 4.

>>> myList = [1, 3, 4, 44, 88] 
>>> myNumber = 5
>>> pos = (bisect_left(myList, myNumber))
>>> myList[pos]
...
44

To get the value that's closest to 5 you could try converting the list to an array and using argmin from numpy like so.

>>> import numpy as np
>>> myNumber = 5   
>>> myList = [1, 3, 4, 44, 88] 
>>> myArray = np.array(myList)
>>> pos = (np.abs(myArray-myNumber)).argmin()
>>> myArray[pos]
...
4

I don't know how fast this would be though, my guess would be "not very".

Class 'ViewController' has no initializers in swift

Sometimes this error also appears when you have a var or a let that hasn't been intialized.

For example

class ViewController: UIViewController {
    var x: Double
    // or
    var y: String
    // or
    let z: Int
}

Depending on what your variable is supposed to do you might either set that var type as an optional or initialize it with a value like the following

class ViewController: UIViewCOntroller {
    // Set an initial value for the variable
    var x: Double = 0
    // or an optional String
    var y: String?
    // or
    let z: Int = 2
}

Create dataframe from a matrix

I've found the following "cheat" to work very neatly and error-free

> dimnames <- list(time=c(0, 0.5, 1), name=c("C_0", "C_1"))
> mat <- matrix(data, ncol=2, nrow=3, dimnames=dimnames)
> head(mat, 2) #this returns the number of rows indicated in a data frame format
> df <- data.frame(head(mat, 2)) #"data.frame" might not be necessary

Et voila!

How to send 500 Internal Server Error error from a PHP script

header($_SERVER['SERVER_PROTOCOL'] . ' 500 Internal Server Error', true, 500);

SQL "select where not in subquery" returns no results

select *
from Common c
where not exists (select t1.commonid from table1 t1 where t1.commonid = c.commonid)
and not exists (select t2.commonid from table2 t2 where t2.commonid = c.commonid)

Import Excel Spreadsheet Data to an EXISTING sql table?

Saudate, I ran across this looking for a different problem. You most definitely can use the Sql Server Import wizard to import data into a new table. Of course, you do not wish to leave that table in the database, so my suggesting is that you import into a new table, then script the data in query manager to insert into the existing table. You can add a line to drop the temp table created by the import wizard as the last step upon successful completion of the script.

I believe your original issue is in fact related to Sql Server 64 bit and is due to your having a 32 bit Excel and these drivers don't play well together. I did run into a very similar issue when first using 64 bit excel.

Difference Between Select and SelectMany

Select many is like cross join operation in SQL where it takes the cross product.
For example if we have

Set A={a,b,c}
Set B={x,y}

Select many can be used to get the following set

{ (x,a) , (x,b) , (x,c) , (y,a) , (y,b) , (y,c) }

Note that here we take the all the possible combinations that can be made from the elements of set A and set B.

Here is a LINQ example you can try

List<string> animals = new List<string>() { "cat", "dog", "donkey" };
List<int> number = new List<int>() { 10, 20 };

var mix = number.SelectMany(num => animals, (n, a) => new { n, a });

the mix will have following elements in flat structure like

{(10,cat), (10,dog), (10,donkey), (20,cat), (20,dog), (20,donkey)}

How do I create dynamic properties in C#?

Create a Hashtable called "Properties" and add your properties to it.

Preventing form resubmission

Directly, you can't, and that's a good thing. The browser's alert is there for a reason. This thread should answer your question:

Prevent Back button from showing POST confirmation alert

Two key workarounds suggested were the PRG pattern, and an AJAX submit followed by a scripting relocation.

Note that if your method allows for a GET and not a POST submission method, then that would both solve the problem and better fit with convention. Those solutions are provided on the assumption you want/need to POST data.

Multiple Buttons' OnClickListener() android

public class MainActivity extends AppCompatActivity implements OnClickListener  {
    Button  b1,b2;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        b1= (Button) findViewById(R.id.button);
        b2= (Button) findViewById(R.id.button2);
        b1.setOnClickListener(this);
        b2.setOnClickListener(this);
    }


    @Override
    public void onClick(View v)
    {
        if(v.getId()==R.id.button)
        {
            Intent intent=new Intent(getApplicationContext(),SignIn.class);
            startActivity(intent);
        }
        else if (v.getId()==R.id.button2)
        {
            Intent in=new Intent(getApplicationContext(),SignUpactivity.class);
            startActivity(in);
        }
    }
}

Very Simple Image Slider/Slideshow with left and right button. No autoplay

Why try to reinvent the wheel? There are more lightweight jQuery slideshow solutions out there then you could poke a stick at, and someone has already done the hard work for you and thought about issues that you might run into (cross-browser compatability etc).

jQuery Cycle is one of my favourite light weight libraries.

What you want to achieve could be done in just

    jQuery("#slideshow").cycle({
    timeout:0, // no autoplay
    fx: 'fade', //fade effect, although there are heaps
    next: '#next',
    prev: '#prev'
    });

JSFIDDLE TO SEE HOW EASY IT IS

How do you make sure email you send programmatically is not automatically marked as spam?

It could very well be the case that people who sign up for your service are entering emails with typing mistakes that you do not correct. For example: chris@gmial.com -or- james@hotnail.com.

And such domains are configured to be used as spamtraps which will automatically flag your email server's IP and/or domain and hurt its reputation.

To avoid this, do a double-check for the email address that is entered upon your product subscription. Also, send a confirmation email to really ensure that this email address is 100% validated by a human being that is entering the confirmation email, before you send them the product key or accept their subscription. The verification email should require the recipient to click a link or reply in order to really confirm that the owner of the mailbox is the person who signed up.

How to compare arrays in JavaScript?

Herer's my solution:

/**
 * Tests two data structures for equality
 * @param {object} x
 * @param {object} y
 * @returns {boolean}
 */
var equal = function(x, y) {
    if (typeof x !== typeof y) return false;
    if (x instanceof Array && y instanceof Array && x.length !== y.length) return false;
    if (typeof x === 'object') {
        for (var p in x) if (x.hasOwnProperty(p)) {
            if (typeof x[p] === 'function' && typeof y[p] === 'function') continue;
            if (x[p] instanceof Array && y[p] instanceof Array && x[p].length !== y[p].length) return false;
            if (typeof x[p] !== typeof y[p]) return false;
            if (typeof x[p] === 'object' && typeof y[p] === 'object') { if (!equal(x[p], y[p])) return false; } else
            if (x[p] !== y[p]) return false;
        }
    } else return x === y;
    return true;
};

Works with any nested data structure, and obviously ignores objects' methods. Don't even think of extending Object.prototype with this method, when I tried this once, jQuery broke ;)

For most arrays it's still faster than most of serialization solutions. It's probably the fastest compare method for arrays of object records.

Git push error: Unable to unlink old (Permission denied)

git reset --hard

Worked for me

How to add include path in Qt Creator?

If you use custom Makefiles, you can double click on the .includes file and add it there.

Check if ADODB connection is open

ADO Recordset has .State property, you can check if its value is adStateClosed or adStateOpen

If Not (rs Is Nothing) Then
  If (rs.State And adStateOpen) = adStateOpen Then rs.Close
  Set rs = Nothing
End If

MSDN about State property

Edit; The reason not to check .State against 1 or 0 is because even if it works 99.99% of the time, it is still possible to have other flags set which will cause the If statement fail the adStateOpen check.

Edit2:

For Late binding without the ActiveX Data Objects referenced, you have few options. Use the value of adStateOpen constant from ObjectStateEnum

If Not (rs Is Nothing) Then
  If (rs.State And 1) = 1 Then rs.Close
  Set rs = Nothing
End If

Or you can define the constant yourself to make your code more readable (defining them all for a good example.)

Const adStateClosed As Long = 0 'Indicates that the object is closed.
Const adStateOpen As Long = 1 'Indicates that the object is open.
Const adStateConnecting As Long = 2 'Indicates that the object is connecting.
Const adStateExecuting As Long = 4 'Indicates that the object is executing a command.
Const adStateFetching As Long = 8 'Indicates that the rows of the object are being retrieved.    

[...]

If Not (rs Is Nothing) Then

    ' ex. If (0001 And 0001) = 0001 (only open flag) -> true
    ' ex. If (1001 And 0001) = 0001 (open and retrieve) -> true
    '    This second example means it is open, but its value is not 1
    '    and If rs.State = 1 -> false, even though it is open
    If (rs.State And adStateOpen) = adStateOpen Then 
        rs.Close
    End If

    Set rs = Nothing
End If

Securely storing passwords for use in python script

the secure way is encrypt your sensitive data by AES and the encryption key is derivation by password-based key derivation function (PBE), the master password used to encrypt/decrypt the encrypt key for AES.

master password -> secure key-> encrypt data by the key

You can use pbkdf2

from PBKDF2 import PBKDF2
from Crypto.Cipher import AES
import os
salt = os.urandom(8)    # 64-bit salt
key = PBKDF2("This passphrase is a secret.", salt).read(32) # 256-bit key
iv = os.urandom(16)     # 128-bit IV
cipher = AES.new(key, AES.MODE_CBC, iv)

make sure to store the salt/iv/passphrase , and decrypt using same salt/iv/passphase

Weblogic used similar approach to protect passwords in config files

Align HTML input fields by :

http://jsfiddle.net/T6zhj/1/

Using display table-cell/row will do the job without any width needed.

The html :

 <html>
  <div>
      <div class="row"><label>Name:</label><input type="text"></div>
      <div class="row"><label>Email Address:</label><input type = "text"></div>
      <div class="row"><label>Description of the input value:</label><input type="text"></div>
  </div>
 </html>

The Css :

label{
    display: table-cell;
    text-align: right;
}
input {
  display: table-cell;
}
div.row{
    display:table-row;
}

Regex to match words of a certain length

^\w{0,10}$ # allows words of up to 10 characters.
^\w{5,}$   # allows words of more than 4 characters.
^\w{5,10}$ # allows words of between 5 and 10 characters.

ORA-00972 identifier is too long alias column name

I'm using Argos reporting system as a front end and Oracle in back. I just encountered this error and it was caused by a string with a double quote at the start and a single quote at the end. Replacing the double quote with a single solved the issue.

Enable remote connections for SQL Server Express 2012

I had the same issue with SQL Server 2014 locally installed named instance. Connecting using the FQDN\InstanceName would fail, while connecting using only my hostname\InstanceName worked. For example: connecting using mycomputername\sql2014 worked, but using mycomputername.mydomain.org\sql2014 did not. DNS resolved correctly, TCP/IP was enabled within SQL Configuration Manager, Windows Firewall rules added (and then turned the firewall off for testing to ensure it wasn't blocking anything), but none of those fixed the problem.

Finally, I had to start the "SQL Server Browser" service on the SQL Server and that fixed the connectivity issue.

I had never realized that the SQL Server Browser service actually assisted the SQL Server in making connections; I was under the impression that it simply helped populate the dropdowns when you clicked "browse for more" servers to connect to, but it actually helps align client requests with the correct port # to use, if the port # is not explicitly assigned (similar to how website bindings help alleviate the same issue on an IIS web server that hosts multiple websites).

This connect item is what gave me the clue about the SQL Server Browser service: https://connect.microsoft.com/SQLServer/feedback/details/589901/unable-to-connect-on-localhost-using-fqdn-machine-name

when you use wstst05\sqlexpress as a server name, the client code separates the machine name from the instance name and the wstst05 is compared against the netbios name. I see no problem for them to match and the connection is considered local. From there, we retrieve the needed information WITHOUT contacting SQL Browser and connect to the SQL instance via Shared Memory without any problem.

when you use wstst05.capatest.local\sqlexpress, the client code fails the comparison of the name (wstst05.capatest.local) to the netbios name (wstst05) and considers the connection "remote". This is by design and we will definitely consider improving this in the future. Anyway, due to considering the connection remote and the fact that it is a named instance, client decides that it needs to use SQLBrowser for name resolution. It attempts to contact SQL Browser on wstst05.capatest.local (UDP port 1434) and apparently that part fails. Hence the error you get.

The reason for the "SQL Server Browser" service from TechNet (emphasis added by me): https://technet.microsoft.com/en-us/library/ms181087(v=sql.120).aspx

From the "Using SQL Server Browser" section:

If the SQL Server Browser service is not running, you are still able to connect to SQL Server if you provide the correct port number or named pipe. For instance, you can connect to the default instance of SQL Server with TCP/IP if it is running on port 1433. However, if the SQL Server Browser service is not running, the following connections do not work:

Any component that tries to connect to a named instance without fully specifying all the parameters (such as the TCP/IP port or named pipe).

Any component that generates or passes server\instance information that could later be used by other components to reconnect.

Connecting to a named instance without providing the port number or pipe.

DAC to a named instance or the default instance if not using TCP/IP port 1433.

The OLAP redirector service.

Enumerating servers in SQL Server Management Studio, Enterprise Manager, or Query Analyzer.

If you are using SQL Server in a client-server scenario (for example, when your application is accessing SQL Server across a network), if you stop or disable the SQL Server Browser service, you must assign a specific port number to each instance and write your client application code to always use that port number. This approach has the following problems:

You must update and maintain client application code to ensure it is connecting to the proper port.

The port you choose for each instance may be used by another service or application on the server, causing the instance of SQL Server to be unavailable.

And more info from the same article from the "How SQL Server Browser Works" section:

Because only one instance of SQL Server can use a port or pipe, different port numbers and pipe names are assigned for named instances, including SQL Server Express. By default, when enabled, both named instances and SQL Server Express are configured to use dynamic ports, that is, an available port is assigned when SQL Server starts. If you want, a specific port can be assigned to an instance of SQL Server. When connecting, clients can specify a specific port; but if the port is dynamically assigned, the port number can change anytime SQL Server is restarted, so the correct port number is unknown to the client. ... When SQL Server clients request SQL Server resources, the client network library sends a UDP message to the server using port 1434. SQL Server Browser responds with the TCP/IP port or named pipe of the requested instance. The network library on the client application then completes the connection by sending a request to the server using the port or named pipe of the desired instance

Convert comma separated string to array in PL/SQL

I was looking for a similar solution where I had multi-byte characters (hyphen, whitespace, underscore) in comma separated lists. So dbms_utility.comma_to_table didn't work for me.

declare
  curr_val varchar2 (255 byte);
  input_str varchar2 (255 byte);
  remaining_str varchar2 (255 byte);
begin
  remaining_str := input_str || ',dummy';  -- this value won't output
  while (regexp_like (remaining_str, '.+,.+'))
  loop
    curr_val := substr (remaining_str, 1, instr (remaining_str, ',') - 1);
    remaining_str = substr (remaining_str, instr (remaining_str, ',') + 1);
    dbms_output.put_line (curr_val);
  end loop;
end;

This is not an expert answer so I hope someone would improve this answer.

How to fix error ::Format of the initialization string does not conform to specification starting at index 0::

I have wasted 1.5 working days on this error and in the end a coworker solved the issue by replacing User Id by Uid and password by Pwd. The updated connection string for .Net was the error for me

Include php files when they are in different folders

None of the above answers fixed this issue for me. I did it as following (Laravel with Ubuntu server):

<?php
     $footerFile = '/var/www/website/main/resources/views/emails/elements/emailfooter.blade.php';
     include($footerFile);
?>

Subtract 1 day with PHP

How to add 1 year to a date and then subtract 1 day from it in asp.net c#

Convert.ToDateTime(txtDate.Value.Trim()).AddYears(1).AddDays(-1);

How can I share Jupyter notebooks with non-programmers?

Google has recently made public its internal Collaboratory project (link here). You can start a notebook in the same way as starting a Google Sheet or Google Doc, and then simply share the notebook or add collaborators..

For now, this is the easiest way for me.

Jinja2 template not rendering if-elif-else statement properly

You are testing if the values of the variables error and Already are present in RepoOutput[RepoName.index(repo)]. If these variables don't exist then an undefined object is used.

Both of your if and elif tests therefore are false; there is no undefined object in the value of RepoOutput[RepoName.index(repo)].

I think you wanted to test if certain strings are in the value instead:

{% if "error" in RepoOutput[RepoName.index(repo)] %}
    <td id="error"> {{ RepoOutput[RepoName.index(repo)] }} </td>
{% elif "Already" in RepoOutput[RepoName.index(repo) %}
    <td id="good"> {{ RepoOutput[RepoName.index(repo)] }} </td>
{% else %}
    <td id="error"> {{ RepoOutput[RepoName.index(repo)] }} </td>
{% endif %}
</tr>

Other corrections I made:

Used {% elif ... %} instead of {$ elif ... %}.
moved the </tr> tag out of the if conditional structure, it needs to be there always.
put quotes around the id attribute

Note that most likely you want to use a class attribute instead here, not an id, the latter must have a value that must be unique across your HTML document.

Personally, I'd set the class value here and reduce the duplication a little:

{% if "Already" in RepoOutput[RepoName.index(repo)] %}
    {% set row_class = "good" %}
{% else %}
    {% set row_class = "error" %}
{% endif %}
<td class="{{ row_class }}"> {{ RepoOutput[RepoName.index(repo)] }} </td>

MySQL config file location - redhat linux server

In the docker containers(centos based images) it is located at

/etc/mysql/my.cnf

How to get phpmyadmin username and password

Try opening config-db.php, it's inside /etc/phpmyadmin. In my case, the user was phpmyadmin, and my password was correct. Maybe your problem is that you're using the usual 'root' username, and your password could be correct.

Can constructors be async?

I'm not familiar with the async keyword (is this specific to Silverlight or a new feature in the beta version of Visual Studio?), but I think I can give you an idea of why you can't do this.

If I do:

var o = new MyObject();
MessageBox(o.SomeProperty.ToString());

o may not be done initializing before the next line of code runs. An instantiation of your object cannot be assigned until your constructor is completed, and making the constructor asynchronous wouldn't change that so what would be the point? However, you could call an asynchronous method from your constructor and then your constructor could complete and you would get your instantiation while the async method is still doing whatever it needs to do to setup your object.

How do I convert a Python 3 byte-string variable into a regular string?

You had it nearly right in the last line. You want

str(bytes_string, 'utf-8')

because the type of bytes_string is bytes, the same as the type of b'abc'.

Keras model.summary() result - Understanding the # of Parameters

The easiest way to calculate number of neurons in one layer is: Param value / (number of units * 4)

Number of units is in predictivemodel.add(Dense(514,...)
Param value is Param in model.summary() function

For example in Paul Lo's answer , number of neurons in one layer is 264710 / (514 * 4 ) = 130

Disable browser cache for entire ASP.NET website

I know this answer is not 100% related to the question, but it might help someone.

If you want to disable the browser cache for the entire ASP.NET MVC Website, but you only want to do this TEMPORARILY, then it is better to disable the cache in your browser.

Here's a screenshot in Chrome

Passing array in GET for a REST call

As @Ravi_MCA mentioned, /users?ids[]=id1&ids[]=id2 worked for me, too.

When you want to send an array through PATCH or POST method, it's better to use JSON or XML. (I use JSON)
In HTTP Request body you should follow like this:

{"params":["arg1", "arg2", ...]}

You can even use JSON object instead of array.

How do I run Python script using arguments in windows command line

import sys

def hello(a, b):
    print  'hello and that\'s your sum: {0}'.format(a + b)

if __name__ == '__main__':
    hello(int(sys.argv[1]), int(sys.argv[2]))

Moreover see @thibauts answer about how to call python script.

Pandas df.to_csv("file.csv" encode="utf-8") still gives trash characters for minus sign

Your "bad" output is UTF-8 displayed as CP1252.

On Windows, many editors assume the default ANSI encoding (CP1252 on US Windows) instead of UTF-8 if there is no byte order mark (BOM) character at the start of the file. While a BOM is meaningless to the UTF-8 encoding, its UTF-8-encoded presence serves as a signature for some programs. For example, Microsoft Office's Excel requires it even on non-Windows OSes. Try:

df.to_csv('file.csv',encoding='utf-8-sig')

That encoder will add the BOM.

Python creating a dictionary of lists

Personally, I just use JSON to convert things to strings and back. Strings I understand.

import json
s = [('yellow', 1), ('blue', 2), ('yellow', 3), ('blue', 4), ('red', 1)]
mydict = {}
hash = json.dumps(s)
mydict[hash] = "whatever"
print mydict
#{'[["yellow", 1], ["blue", 2], ["yellow", 3], ["blue", 4], ["red", 1]]': 'whatever'}

Xcode 6.1 - How to uninstall command line tools?

You can simply delete this folder

/Library/Developer/CommandLineTools

Please note: This is the root /Library, not user's ~/Library).

How can I iterate over an enum?

too much complicated these solution, i do like that :

enum NodePosition { Primary = 0, Secondary = 1, Tertiary = 2, Quaternary = 3};

const NodePosition NodePositionVector[] = { Primary, Secondary, Tertiary, Quaternary };

for (NodePosition pos : NodePositionVector) {
...
}

MongoDB Data directory /data/db not found

MongoDB needs data directory to store data. Default path is /data/db

When you start MongoDB engine, it searches this directory which is missing in your case. Solution is create this directory and assign rwx permission to user.

If you want to change the path of your data directory then you should specify it while starting mongod server like,

mongod --dbpath /data/<path> --port <port no>

This should help you start your mongod server with custom path and port.

Different ways of loading a file as an InputStream

There are subtle differences as to how the fileName you are passing is interpreted. Basically, you have 2 different methods: ClassLoader.getResourceAsStream() and Class.getResourceAsStream(). These two methods will locate the resource differently.

In Class.getResourceAsStream(path), the path is interpreted as a path local to the package of the class you are calling it from. For example calling, String.class.getResourceAsStream("myfile.txt") will look for a file in your classpath at the following location: "java/lang/myfile.txt". If your path starts with a /, then it will be considered an absolute path, and will start searching from the root of the classpath. So calling String.class.getResourceAsStream("/myfile.txt") will look at the following location in your class path ./myfile.txt.

ClassLoader.getResourceAsStream(path) will consider all paths to be absolute paths. So calling String.class.getClassLoader().getResourceAsStream("myfile.txt") and String.class.getClassLoader().getResourceAsStream("/myfile.txt") will both look for a file in your classpath at the following location: ./myfile.txt.

Everytime I mention a location in this post, it could be a location in your filesystem itself, or inside the corresponding jar file, depending on the Class and/or ClassLoader you are loading the resource from.

In your case, you are loading the class from an Application Server, so your should use Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName) instead of this.getClass().getClassLoader().getResourceAsStream(fileName). this.getClass().getResourceAsStream() will also work.

Read this article for more detailed information about that particular problem.

Warning for users of Tomcat 7 and below

One of the answers to this question states that my explanation seems to be incorrect for Tomcat 7. I've tried to look around to see why that would be the case.

So I've looked at the source code of Tomcat's WebAppClassLoader for several versions of Tomcat. The implementation of findResource(String name) (which is utimately responsible for producing the URL to the requested resource) is virtually identical in Tomcat 6 and Tomcat 7, but is different in Tomcat 8.

In versions 6 and 7, the implementation does not attempt to normalize the resource name. This means that in these versions, classLoader.getResourceAsStream("/resource.txt") may not produce the same result as classLoader.getResourceAsStream("resource.txt") event though it should (since that what the Javadoc specifies). [source code]

In version 8 though, the resource name is normalized to guarantee that the absolute version of the resource name is the one that is used. Therefore, in Tomcat 8, the two calls described above should always return the same result. [source code]

As a result, you have to be extra careful when using ClassLoader.getResourceAsStream() or Class.getResourceAsStream() on Tomcat versions earlier than 8. And you must also keep in mind that class.getResourceAsStream("/resource.txt") actually calls classLoader.getResourceAsStream("resource.txt") (the leading / is stripped).

How to specify "does not contain" in dplyr filter

Note that %in% returns a logical vector of TRUE and FALSE. To negate it, you can use ! in front of the logical statement:

SE_CSVLinelist_filtered <- filter(SE_CSVLinelist_clean, 
 !where_case_travelled_1 %in% 
   c('Outside Canada','Outside province/territory of residence but within Canada'))

Regarding your original approach with -c(...), - is a unary operator that "performs arithmetic on numeric or complex vectors (or objects which can be coerced to them)" (from help("-")). Since you are dealing with a character vector that cannot be coerced to numeric or complex, you cannot use -.

pretty-print JSON using JavaScript

Here's user123444555621's awesome HTML one adapted for terminals. Handy for debugging Node scripts:

function prettyJ(json) {
  if (typeof json !== 'string') {
    json = JSON.stringify(json, undefined, 2);
  }
  return json.replace(/("(\\u[a-zA-Z0-9]{4}|\\[^u]|[^\\"])*"(\s*:)?|\b(true|false|null)\b|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?)/g, 
    function (match) {
      let cls = "\x1b[36m";
      if (/^"/.test(match)) {
        if (/:$/.test(match)) {
          cls = "\x1b[34m";
        } else {
          cls = "\x1b[32m";
        }
      } else if (/true|false/.test(match)) {
        cls = "\x1b[35m"; 
      } else if (/null/.test(match)) {
        cls = "\x1b[31m";
      }
      return cls + match + "\x1b[0m";
    }
  );
}

Usage:

// thing = any json OR string of json
prettyJ(thing);

Is there a way that I can check if a data attribute exists?

In the interest of providing a different answer from the ones above; you could check it with Object.hasOwnProperty(...) like this:

 if( $("#dataTable").data().hasOwnProperty("timer") ){
     // the data-time property exists, now do you business! .....
 }

alternatively, if you have multiple data elements you want to iterate over you can variablize the .data() object and iterate over it like this:

 var objData = $("#dataTable").data();
 for ( data in objData ){
      if( data == 'timer' ){
            //...do the do
      }
 }

Not saying this solution is better than any of the other ones in here, but at least it's another approach...

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

using System;
using System.Data;
using System.Data.SqlClient;

namespace InsertingData
{
    class sqlinsertdata
    {
        static void Main(string[] args)
        {
            try
            { 
            SqlConnection conn = new SqlConnection("Data source=USER-PC; Database=Emp123;User Id=sa;Password=sa123");
            conn.Open();
                SqlCommand cmd = new SqlCommand("insert into <Table Name>values(1,'nagendra',10000);",conn);
                cmd.ExecuteNonQuery();
                Console.WriteLine("Inserting Data Successfully");
                conn.Close();
        }
            catch(Exception e)
            {
                Console.WriteLine("Exception Occre while creating table:" + e.Message + "\t"  + e.GetType());
            }
            Console.ReadKey();

    }
    }
}

How to convert rdd object to dataframe in spark

Method 1: (Scala)

val sqlContext = new org.apache.spark.sql.SQLContext(sc)
import sqlContext.implicits._
val df_2 = sc.parallelize(Seq((1L, 3.0, "a"), (2L, -1.0, "b"), (3L, 0.0, "c"))).toDF("x", "y", "z")

Method 2: (Scala)

case class temp(val1: String,val3 : Double) 

val rdd = sc.parallelize(Seq(
  Row("foo",  0.5), Row("bar",  0.0)
))
val rows = rdd.map({case Row(val1:String,val3:Double) => temp(val1,val3)}).toDF()
rows.show()

Method 1: (Python)

from pyspark.sql import Row
l = [('Alice',2)]
Person = Row('name','age')
rdd = sc.parallelize(l)
person = rdd.map(lambda r:Person(*r))
df2 = sqlContext.createDataFrame(person)
df2.show()

Method 2: (Python)

from pyspark.sql.types import * 
l = [('Alice',2)]
rdd = sc.parallelize(l)
schema =  StructType([StructField ("name" , StringType(), True) , 
StructField("age" , IntegerType(), True)]) 
df3 = sqlContext.createDataFrame(rdd, schema) 
df3.show()

Extracted the value from the row object and then applied the case class to convert rdd to DF

val temp1 = attrib1.map{case Row ( key: Int ) => s"$key" }
val temp2 = attrib2.map{case Row ( key: Int) => s"$key" }

case class RLT (id: String, attrib_1 : String, attrib_2 : String)
import hiveContext.implicits._

val df = result.map{ s => RLT(s(0),s(1),s(2)) }.toDF

Building a complete online payment gateway like Paypal

Big task, chances are you shouldn't reinvent the wheel rather using an existing wheel (such as paypal).

However, if you insist on continuing. Start small, you can use a credit card processing facility (Moneris, Authorize.NET) to process credit cards. Most providers have an API you can use. Be wary that you may need to use different providers depending on the card type (Discover, Visa, Amex, Mastercard) and Country (USA, Canada, UK). So build it so that you can communicate with multiple credit card processing APIs.

Security is essential if you are storing credit cards and payment details. Ensure that you are encrypting things properly.

Again, don't reinvent the wheel. You are better off using an existing provider and focussing your development attention on solving an problem that can't easily be purchase.

Create GUI using Eclipse (Java)

try http://code.google.com/p/swinghtmltemplate/

this will allow you to create gui with html-like syntax

How can I access global variable inside class in Python

I understand using a global variable is sometimes the most convenient thing to do, especially in cases where usage of class makes the easiest thing so much harder (e.g., multiprocessing). I ran into the same problem with declaring global variables and figured it out with some experiments.

The reason that g_c was not changed by the run function within your class is that the referencing to the global name within g_c was not established precisely within the function. The way Python handles global declaration is in fact quite tricky. The command global g_c has two effects:

Preconditions the entrance of the key "g_c" into the dictionary accessible by the built-in function, globals(). However, the key will not appear in the dictionary until after a value is assigned to it.
(Potentially) alters the way Python looks for the variable g_c within the current method.

The full understanding of (2) is particularly complex. First of all, it only potentially alters, because if no assignment to the name g_c occurs within the method, then Python defaults to searching for it among the globals(). This is actually a fairly common thing, as is the case of referencing within a method modules that are imported all the way at the beginning of the code.

However, if an assignment command occurs anywhere within the method, Python defaults to finding the name g_c within local variables. This is true even when a referencing occurs before an actual assignment, which will lead to the classic error:

UnboundLocalError: local variable 'g_c' referenced before assignment

Now, if the declaration global g_c occurs anywhere within the method, even after any referencing or assignment, then Python defaults to finding the name g_c within global variables. However, if you are feeling experimentative and place the declaration after a reference, you will be rewarded with a warning:

SyntaxWarning: name 'g_c' is used prior to global declaration

If you think about it, the way the global declaration works in Python is clearly woven into and consistent with how Python normally works. It's just when you actually want a global variable to work, the norm becomes annoying.

Here is a code that summarizes what I just said (with a few more observations):

g_c = 0
print ("Initial value of g_c: " + str(g_c))
print("Variable defined outside of method automatically global? "
      + str("g_c" in globals()))

class TestClass():
    def direct_print(self):
        print("Directly printing g_c without declaration or modification: "
              + str(g_c))
        #Without any local reference to the name
        #Python defaults to search for the variable in globals()
        #This of course happens for all the module names you import

    def mod_without_dec(self):
        g_c = 1
        #A local assignment without declaring reference to global variable
        #makes Python default to access local name
        print ("After mod_without_dec, local g_c=" + str(g_c))
        print ("After mod_without_dec, global g_c=" + str(globals()["g_c"]))


    def mod_with_late_dec(self):
        g_c = 2
        #Even with a late declaration, the global variable is accessed
        #However, a syntax warning will be issued
        global g_c
        print ("After mod_with_late_dec, local g_c=" + str(g_c))
        print ("After mod_with_late_dec, global g_c=" + str(globals()["g_c"]))

    def mod_without_dec_error(self):
        try:
            print("This is g_c" + str(g_c))
        except:
            print("Error occured while accessing g_c")
            #If you try to access g_c without declaring it global
            #but within the method you also alter it at some point
            #then Python will not search for the name in globals()
            #!!!!!Even if the assignment command occurs later!!!!!
        g_c = 3

    def sound_practice(self):
        global g_c
        #With correct declaration within the method
        #The local name g_c becomes an alias for globals()["g_c"]
        g_c = 4
        print("In sound_practice, the name g_c points to: " + str(g_c))


t = TestClass()
t.direct_print()
t.mod_without_dec()
t.mod_with_late_dec()
t.mod_without_dec_error()
t.sound_practice()

Generating a PNG with matplotlib when DISPLAY is undefined

When signing into the server to execute the code use this instead:

ssh -X username@servername

the -X will get rid of the no display name and no $DISPLAY environment variable error

What does it mean by command cd /d %~dp0 in Windows

Let's dissect it. There are three parts:

cd -- This is change directory command.
/d -- This switch makes cd change both drive and directory at once. Without it you would have to do cd %~d0 & cd %~p0. (%~d0 Changs active drive, cd %~p0 change the directory).
%~dp0 -- This can be dissected further into three parts:
1. %0 -- This represents zeroth parameter of your batch script. It expands into the name of the batch file itself.
2. %~0 -- The ~ there strips double quotes (") around the expanded argument.
3. %dp0 -- The d and p there are modifiers of the expansion. The d forces addition of a drive letter and the p adds full path.

How to customize message box

Here is the code needed to create your own message box:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace MyStuff
{
    public class MyLabel : Label
    {
        public static Label Set(string Text = "", Font Font = null, Color ForeColor = new Color(), Color BackColor = new Color())
        {
            Label l = new Label();
            l.Text = Text;
            l.Font = (Font == null) ? new Font("Calibri", 12) : Font;
            l.ForeColor = (ForeColor == new Color()) ? Color.Black : ForeColor;
            l.BackColor = (BackColor == new Color()) ? SystemColors.Control : BackColor;
            l.AutoSize = true;
            return l;
        }
    }
    public class MyButton : Button
    {
        public static Button Set(string Text = "", int Width = 102, int Height = 30, Font Font = null, Color ForeColor = new Color(), Color BackColor = new Color())
        {
            Button b = new Button();
            b.Text = Text;
            b.Width = Width;
            b.Height = Height;
            b.Font = (Font == null) ? new Font("Calibri", 12) : Font;
            b.ForeColor = (ForeColor == new Color()) ? Color.Black : ForeColor;
            b.BackColor = (BackColor == new Color()) ? SystemColors.Control : BackColor;
            b.UseVisualStyleBackColor = (b.BackColor == SystemColors.Control);
            return b;
        }
    }
    public class MyImage : PictureBox
    {
        public static PictureBox Set(string ImagePath = null, int Width = 60, int Height = 60)
        {
            PictureBox i = new PictureBox();
            if (ImagePath != null)
            {
                i.BackgroundImageLayout = ImageLayout.Zoom;
                i.Location = new Point(9, 9);
                i.Margin = new Padding(3, 3, 2, 3);
                i.Size = new Size(Width, Height);
                i.TabStop = false;
                i.Visible = true;
                i.BackgroundImage = Image.FromFile(ImagePath);
            }
            else
            {
                i.Visible = true;
                i.Size = new Size(0, 0);
            }
            return i;
        }
    }
    public partial class MyMessageBox : Form
    {
        private MyMessageBox()
        {
            this.panText = new FlowLayoutPanel();
            this.panButtons = new FlowLayoutPanel();
            this.SuspendLayout();
            // 
            // panText
            // 
            this.panText.Parent = this;
            this.panText.AutoScroll = true;
            this.panText.AutoSize = true;
            this.panText.AutoSizeMode = AutoSizeMode.GrowAndShrink;
            //this.panText.Location = new Point(90, 90);
            this.panText.Margin = new Padding(0);
            this.panText.MaximumSize = new Size(500, 300);
            this.panText.MinimumSize = new Size(108, 50);
            this.panText.Size = new Size(108, 50);
            // 
            // panButtons
            // 
            this.panButtons.AutoSize = true;
            this.panButtons.AutoSizeMode = AutoSizeMode.GrowAndShrink;
            this.panButtons.FlowDirection = FlowDirection.RightToLeft;
            this.panButtons.Location = new Point(89, 89);
            this.panButtons.Margin = new Padding(0);
            this.panButtons.MaximumSize = new Size(580, 150);
            this.panButtons.MinimumSize = new Size(108, 0);
            this.panButtons.Size = new Size(108, 35);
            // 
            // MyMessageBox
            // 
            this.AutoScaleDimensions = new SizeF(8F, 19F);
            this.AutoScaleMode = AutoScaleMode.Font;
            this.ClientSize = new Size(206, 133);
            this.Controls.Add(this.panButtons);
            this.Controls.Add(this.panText);
            this.Font = new Font("Calibri", 12F, FontStyle.Regular, GraphicsUnit.Point, ((byte)(0)));
            this.FormBorderStyle = FormBorderStyle.FixedSingle;
            this.Margin = new Padding(4);
            this.MaximizeBox = false;
            this.MinimizeBox = false;
            this.MinimumSize = new Size(168, 132);
            this.Name = "MyMessageBox";
            this.ShowIcon = false;
            this.ShowInTaskbar = false;
            this.StartPosition = FormStartPosition.CenterScreen;
            this.ResumeLayout(false);
            this.PerformLayout();
        }
        public static string Show(Label Label, string Title = "", List<Button> Buttons = null, PictureBox Image = null)
        {
            List<Label> Labels = new List<Label>();
            Labels.Add(Label);
            return Show(Labels, Title, Buttons, Image);
        }
        public static string Show(string Label, string Title = "", List<Button> Buttons = null, PictureBox Image = null)
        {
            List<Label> Labels = new List<Label>();
            Labels.Add(MyLabel.Set(Label));
            return Show(Labels, Title, Buttons, Image);
        }
        public static string Show(List<Label> Labels = null, string Title = "", List<Button> Buttons = null, PictureBox Image = null)
        {
            if (Labels == null) Labels = new List<Label>();
            if (Labels.Count == 0) Labels.Add(MyLabel.Set(""));
            if (Buttons == null) Buttons = new List<Button>();
            if (Buttons.Count == 0) Buttons.Add(MyButton.Set("OK"));
            List<Button> buttons = new List<Button>(Buttons);
            buttons.Reverse();

            int ImageWidth = 0;
            int ImageHeight = 0;
            int LabelWidth = 0;
            int LabelHeight = 0;
            int ButtonWidth = 0;
            int ButtonHeight = 0;
            int TotalWidth = 0;
            int TotalHeight = 0;

            MyMessageBox mb = new MyMessageBox();

            mb.Text = Title;

            //Image
            if (Image != null)
            {
                mb.Controls.Add(Image);
                Image.MaximumSize = new Size(150, 300);
                ImageWidth = Image.Width + Image.Margin.Horizontal;
                ImageHeight = Image.Height + Image.Margin.Vertical;
            }

            //Labels
            List<int> il = new List<int>();
            mb.panText.Location = new Point(9 + ImageWidth, 9);
            foreach (Label l in Labels)
            {
                mb.panText.Controls.Add(l);
                l.Location = new Point(200, 50);
                l.MaximumSize = new Size(480, 2000);
                il.Add(l.Width);
            }
            int mw = Labels.Max(x => x.Width);
            il.ToString();
            Labels.ForEach(l => l.MinimumSize = new Size(Labels.Max(x => x.Width), 1));
            mb.panText.Height = Labels.Sum(l => l.Height);
            mb.panText.MinimumSize = new Size(Labels.Max(x => x.Width) + mb.ScrollBarWidth(Labels), ImageHeight);
            mb.panText.MaximumSize = new Size(Labels.Max(x => x.Width) + mb.ScrollBarWidth(Labels), 300);
            LabelWidth = mb.panText.Width;
            LabelHeight = mb.panText.Height;

            //Buttons
            foreach (Button b in buttons)
            {
                mb.panButtons.Controls.Add(b);
                b.Location = new Point(3, 3);
                b.TabIndex = Buttons.FindIndex(i => i.Text == b.Text);
                b.Click += new EventHandler(mb.Button_Click);
            }
            ButtonWidth = mb.panButtons.Width;
            ButtonHeight = mb.panButtons.Height;

            //Set Widths
            if (ButtonWidth > ImageWidth + LabelWidth)
            {
                Labels.ForEach(l => l.MinimumSize = new Size(ButtonWidth - ImageWidth - mb.ScrollBarWidth(Labels), 1));
                mb.panText.Height = Labels.Sum(l => l.Height);
                mb.panText.MinimumSize = new Size(Labels.Max(x => x.Width) + mb.ScrollBarWidth(Labels), ImageHeight);
                mb.panText.MaximumSize = new Size(Labels.Max(x => x.Width) + mb.ScrollBarWidth(Labels), 300);
                LabelWidth = mb.panText.Width;
                LabelHeight = mb.panText.Height;
            }
            TotalWidth = ImageWidth + LabelWidth;

            //Set Height
            TotalHeight = LabelHeight + ButtonHeight;

            mb.panButtons.Location = new Point(TotalWidth - ButtonWidth + 9, mb.panText.Location.Y + mb.panText.Height);

            mb.Size = new Size(TotalWidth + 25, TotalHeight + 47);
            mb.ShowDialog();
            return mb.Result;
        }

        private FlowLayoutPanel panText;
        private FlowLayoutPanel panButtons;
        private int ScrollBarWidth(List<Label> Labels)
        {
            return (Labels.Sum(l => l.Height) > 300) ? 23 : 6;
        }

        private void Button_Click(object sender, EventArgs e)
        {
            Result = ((Button)sender).Text;
            Close();
        }

        private string Result = "";
    }
}

What is path of JDK on Mac ?

The location has changed from Java 6 (provided by Apple) to Java 7 and onwards (provided by Oracle). The best generic way to find this out is to run

/usr/libexec/java_home

This is the natively supported way to find out both the path to the default Java installation as well as all alternative ones present.

If you check out its help text (java_home -h), you'll see that you can use this command to reliably start a Java program on OS X (java_home --exec ...), with the ability to explicitly specify the desired Java version and architecture, or even request the user to install it if missing.

A more pedestrian approach, but one which will help you trace specifically which Java installation the command java resolves into, goes like this:

run
```
which java
```
if that gives you something like /usr/bin/java, which is a symbolic link to the real location, run
```
ls -l `which java`
```
On my system, this outputs
```
/usr/bin/java -> /Library/Java/JavaVirtualMachines/jdk1.7.0_25.jdk/Contents/Home/bin/java
```
and therefrom you can read the Java home directory;
if usr/bin/java points to another symbolic link, recursively apply the same approach with
```
ls -l <whatever the /usr/bin/java symlink points to>
```

An important variation is the setup you get if you start by installing Apple's Java and later install Oracle's. In that case Step 2 above will give you

/usr/bin/java -> /System/Library/Frameworks/JavaVM.framework/Commands/java

and that particular java binary is a stub which will resolve the actual java command to call by consulting the JAVA_HOME environment variable and, if it's not set or doesn't point to a Java home directory, will fall back to calling java_home. It is important to have this in mind when debugging your setup.

Set a path variable with spaces in the path in a Windows .cmd file or batch file

I always place the path in double quotes when I am creating a .bat file. (I just added the PAUSE so it wont close the screen.)

For example:

"C:\Program Files\PageTech\PCLReader64_131\PCLReader64.exe"
PAUSE

jquery find element by specific class when element has multiple classes

You can select elements with multiple classes like so:

$("element.firstClass.anotherClass");

Simply chain the next class onto the first one, without a space (spaces mean "children of").

Split comma-separated input box values into array in jquery, and loop through it

use js split() method to create an array

var keywords = $('#searchKeywords').val().split(",");

then loop through the array using jQuery.each() function. as the documentation says:

In the case of an array, the callback is passed an array index and a corresponding array value each time

$.each(keywords, function(i, keyword){
   console.log(keyword);
});

Do sessions really violate RESTfulness?

First of all, REST is not a religion and should not be approached as such. While there are advantages to RESTful services, you should only follow the tenets of REST as far as they make sense for your application.

That said, authentication and client side state do not violate REST principles. While REST requires that state transitions be stateless, this is referring to the server itself. At the heart, all of REST is about documents. The idea behind statelessness is that the SERVER is stateless, not the clients. Any client issuing an identical request (same headers, cookies, URI, etc) should be taken to the same place in the application. If the website stored the current location of the user and managed navigation by updating this server side navigation variable, then REST would be violated. Another client with identical request information would be taken to a different location depending on the server-side state.

Google's web services are a fantastic example of a RESTful system. They require an authentication header with the user's authentication key to be passed upon every request. This does violate REST principles slightly, because the server is tracking the state of the authentication key. The state of this key must be maintained and it has some sort of expiration date/time after which it no longer grants access. However, as I mentioned at the top of my post, sacrifices must be made to allow an application to actually work. That said, authentication tokens must be stored in a way that allows all possible clients to continue granting access during their valid times. If one server is managing the state of the authentication key to the point that another load balanced server cannot take over fulfilling requests based on that key, you have started to really violate the principles of REST. Google's services ensure that, at any time, you can take an authentication token you were using on your phone against load balance server A and hit load balance server B from your desktop and still have access to the system and be directed to the same resources if the requests were identical.

What it all boils down to is that you need to make sure your authentication tokens are validated against a backing store of some sort (database, cache, whatever) to ensure that you preserve as many of the REST properties as possible.

I hope all of that made sense. You should also check out the Constraints section of the wikipedia article on Representational State Transfer if you haven't already. It is particularly enlightening with regard to what the tenets of REST are actually arguing for and why.

How to remove "rows" with a NA value?

dat <- data.frame(x1 = c(1,2,3, NA, 5), x2 = c(100, NA, 300, 400, 500))

na.omit(dat)
  x1  x2
1  1 100
3  3 300
5  5 500

Android - Round to 2 decimal places

How to download videos from youtube on java?

Ref :Youtube Video Download (Android/Java)

Edit 3

You can use the Lib : https://github.com/HaarigerHarald/android-youtubeExtractor

Ex :

String youtubeLink = "http://youtube.com/watch?v=xxxx";

new YouTubeExtractor(this) {
@Override
public void onExtractionComplete(SparseArray<YtFile> ytFiles, VideoMeta vMeta) {
    if (ytFiles != null) {
        int itag = 22;
    String downloadUrl = ytFiles.get(itag).getUrl();
    }
}
}.extract(youtubeLink, true, true);

They decipherSignature using :

private boolean decipherSignature(final SparseArray<String> encSignatures) throws IOException {
    // Assume the functions don't change that much
    if (decipherFunctionName == null || decipherFunctions == null) {
        String decipherFunctUrl = "https://s.ytimg.com/yts/jsbin/" + decipherJsFileName;

        BufferedReader reader = null;
        String javascriptFile;
        URL url = new URL(decipherFunctUrl);
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestProperty("User-Agent", USER_AGENT);
        try {
            reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
            StringBuilder sb = new StringBuilder("");
            String line;
            while ((line = reader.readLine()) != null) {
                sb.append(line);
                sb.append(" ");
            }
            javascriptFile = sb.toString();
        } finally {
            if (reader != null)
                reader.close();
            urlConnection.disconnect();
        }

        if (LOGGING)
            Log.d(LOG_TAG, "Decipher FunctURL: " + decipherFunctUrl);
        Matcher mat = patSignatureDecFunction.matcher(javascriptFile);
        if (mat.find()) {
            decipherFunctionName = mat.group(1);
            if (LOGGING)
                Log.d(LOG_TAG, "Decipher Functname: " + decipherFunctionName);

            Pattern patMainVariable = Pattern.compile("(var |\\s|,|;)" + decipherFunctionName.replace("$", "\\$") +
                    "(=function\\((.{1,3})\\)\\{)");

            String mainDecipherFunct;

            mat = patMainVariable.matcher(javascriptFile);
            if (mat.find()) {
                mainDecipherFunct = "var " + decipherFunctionName + mat.group(2);
            } else {
                Pattern patMainFunction = Pattern.compile("function " + decipherFunctionName.replace("$", "\\$") +
                        "(\\((.{1,3})\\)\\{)");
                mat = patMainFunction.matcher(javascriptFile);
                if (!mat.find())
                    return false;
                mainDecipherFunct = "function " + decipherFunctionName + mat.group(2);
            }

            int startIndex = mat.end();

            for (int braces = 1, i = startIndex; i < javascriptFile.length(); i++) {
                if (braces == 0 && startIndex + 5 < i) {
                    mainDecipherFunct += javascriptFile.substring(startIndex, i) + ";";
                    break;
                }
                if (javascriptFile.charAt(i) == '{')
                    braces++;
                else if (javascriptFile.charAt(i) == '}')
                    braces--;
            }
            decipherFunctions = mainDecipherFunct;
            // Search the main function for extra functions and variables
            // needed for deciphering
            // Search for variables
            mat = patVariableFunction.matcher(mainDecipherFunct);
            while (mat.find()) {
                String variableDef = "var " + mat.group(2) + "={";
                if (decipherFunctions.contains(variableDef)) {
                    continue;
                }
                startIndex = javascriptFile.indexOf(variableDef) + variableDef.length();
                for (int braces = 1, i = startIndex; i < javascriptFile.length(); i++) {
                    if (braces == 0) {
                        decipherFunctions += variableDef + javascriptFile.substring(startIndex, i) + ";";
                        break;
                    }
                    if (javascriptFile.charAt(i) == '{')
                        braces++;
                    else if (javascriptFile.charAt(i) == '}')
                        braces--;
                }
            }
            // Search for functions
            mat = patFunction.matcher(mainDecipherFunct);
            while (mat.find()) {
                String functionDef = "function " + mat.group(2) + "(";
                if (decipherFunctions.contains(functionDef)) {
                    continue;
                }
                startIndex = javascriptFile.indexOf(functionDef) + functionDef.length();
                for (int braces = 0, i = startIndex; i < javascriptFile.length(); i++) {
                    if (braces == 0 && startIndex + 5 < i) {
                        decipherFunctions += functionDef + javascriptFile.substring(startIndex, i) + ";";
                        break;
                    }
                    if (javascriptFile.charAt(i) == '{')
                        braces++;
                    else if (javascriptFile.charAt(i) == '}')
                        braces--;
                }
            }

            if (LOGGING)
                Log.d(LOG_TAG, "Decipher Function: " + decipherFunctions);
            decipherViaWebView(encSignatures);
            if (CACHING) {
                writeDeciperFunctToChache();
            }
        } else {
            return false;
        }
    } else {
        decipherViaWebView(encSignatures);
    }
    return true;
}

Now with use of this library High Quality Videos Lossing Audio so i use the MediaMuxer for Murging Audio and Video for Final Output

Edit 1

https://stackoverflow.com/a/15240012/9909365

Why the previous answer not worked

 Pattern p2 = Pattern.compile("sig=(.*?)[&]");
        Matcher m2 = p2.matcher(url);
        String sig = null;
        if (m2.find()) {
            sig = m2.group(1);
        }

As of November 2016, this is a little rough around the edges, but displays the basic principle. The url_encoded_fmt_stream_map today does not have a space after the colon (better make this optional) and "sig" has been changed to "signature"

and while i am debuging the code i found the new keyword its signature&s in many video's URL

here edited answer

private static final HashMap<String, Meta> typeMap = new HashMap<String, Meta>();

initTypeMap(); call first

class Meta {
    public String num;
    public String type;
    public String ext;

    Meta(String num, String ext, String type) {
        this.num = num;
        this.ext = ext;
        this.type = type;
    }
}

class Video {
    public String ext = "";
    public String type = "";
    public String url = "";

    Video(String ext, String type, String url) {
        this.ext = ext;
        this.type = type;
        this.url = url;
    }
}

public ArrayList<Video> getStreamingUrisFromYouTubePage(String ytUrl)
        throws IOException {
    if (ytUrl == null) {
        return null;
    }

    // Remove any query params in query string after the watch?v=<vid> in
    // e.g.
    // http://www.youtube.com/watch?v=0RUPACpf8Vs&feature=youtube_gdata_player
    int andIdx = ytUrl.indexOf('&');
    if (andIdx >= 0) {
        ytUrl = ytUrl.substring(0, andIdx);
    }

    // Get the HTML response
    /* String userAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0.1)";*/
   /* HttpClient client = new DefaultHttpClient();
    client.getParams().setParameter(CoreProtocolPNames.USER_AGENT,
            userAgent);
    HttpGet request = new HttpGet(ytUrl);
    HttpResponse response = client.execute(request);*/
    String html = "";
    HttpsURLConnection c = (HttpsURLConnection) new URL(ytUrl).openConnection();
    c.setRequestMethod("GET");
    c.setDoOutput(true);
    c.connect();
    InputStream in = c.getInputStream();
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
    StringBuilder str = new StringBuilder();
    String line = null;
    while ((line = reader.readLine()) != null) {
        str.append(line.replace("\\u0026", "&"));
    }
    in.close();
    html = str.toString();

    // Parse the HTML response and extract the streaming URIs
    if (html.contains("verify-age-thumb")) {
        Log.e("Downloader", "YouTube is asking for age verification. We can't handle that sorry.");
        return null;
    }

    if (html.contains("das_captcha")) {
        Log.e("Downloader", "Captcha found, please try with different IP address.");
        return null;
    }

    Pattern p = Pattern.compile("stream_map\":\"(.*?)?\"");
    // Pattern p = Pattern.compile("/stream_map=(.[^&]*?)\"/");
    Matcher m = p.matcher(html);
    List<String> matches = new ArrayList<String>();
    while (m.find()) {
        matches.add(m.group());
    }

    if (matches.size() != 1) {
        Log.e("Downloader", "Found zero or too many stream maps.");
        return null;
    }

    String urls[] = matches.get(0).split(",");
    HashMap<String, String> foundArray = new HashMap<String, String>();
    for (String ppUrl : urls) {
        String url = URLDecoder.decode(ppUrl, "UTF-8");
        Log.e("URL","URL : "+url);

        Pattern p1 = Pattern.compile("itag=([0-9]+?)[&]");
        Matcher m1 = p1.matcher(url);
        String itag = null;
        if (m1.find()) {
            itag = m1.group(1);
        }

        Pattern p2 = Pattern.compile("signature=(.*?)[&]");
        Matcher m2 = p2.matcher(url);
        String sig = null;
        if (m2.find()) {
            sig = m2.group(1);
        } else {
            Pattern p23 = Pattern.compile("signature&s=(.*?)[&]");
            Matcher m23 = p23.matcher(url);
            if (m23.find()) {
                sig = m23.group(1);
            }
        }

        Pattern p3 = Pattern.compile("url=(.*?)[&]");
        Matcher m3 = p3.matcher(ppUrl);
        String um = null;
        if (m3.find()) {
            um = m3.group(1);
        }

        if (itag != null && sig != null && um != null) {
            Log.e("foundArray","Adding Value");
            foundArray.put(itag, URLDecoder.decode(um, "UTF-8") + "&"
                    + "signature=" + sig);
        }
    }
    Log.e("foundArray","Size : "+foundArray.size());
    if (foundArray.size() == 0) {
        Log.e("Downloader", "Couldn't find any URLs and corresponding signatures");
        return null;
    }


    ArrayList<Video> videos = new ArrayList<Video>();

    for (String format : typeMap.keySet()) {
        Meta meta = typeMap.get(format);

        if (foundArray.containsKey(format)) {
            Video newVideo = new Video(meta.ext, meta.type,
                    foundArray.get(format));
            videos.add(newVideo);
            Log.d("Downloader", "YouTube Video streaming details: ext:" + newVideo.ext
                    + ", type:" + newVideo.type + ", url:" + newVideo.url);
        }
    }

    return videos;
}

private class YouTubePageStreamUriGetter extends AsyncTask<String, String, ArrayList<Video>> {
    ProgressDialog progressDialog;

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog = ProgressDialog.show(webViewActivity.this, "",
                "Connecting to YouTube...", true);
    }

    @Override
    protected ArrayList<Video> doInBackground(String... params) {
        ArrayList<Video> fVideos = new ArrayList<>();
        String url = params[0];
        try {
            ArrayList<Video> videos = getStreamingUrisFromYouTubePage(url);
            /*                Log.e("Downloader","Size of Video : "+videos.size());*/
            if (videos != null && !videos.isEmpty()) {
                for (Video video : videos)
                {
                    Log.e("Downloader", "ext : " + video.ext);
                    if (video.ext.toLowerCase().contains("mp4") || video.ext.toLowerCase().contains("3gp") || video.ext.toLowerCase().contains("flv") || video.ext.toLowerCase().contains("webm")) {
                        ext = video.ext.toLowerCase();
                        fVideos.add(new Video(video.ext,video.type,video.url));
                    }
                }


                return fVideos;
            }
        } catch (Exception e) {
            e.printStackTrace();
            Log.e("Downloader", "Couldn't get YouTube streaming URL", e);
        }
        Log.e("Downloader", "Couldn't get stream URI for " + url);
        return null;
    }

    @Override
    protected void onPostExecute(ArrayList<Video> streamingUrl) {
        super.onPostExecute(streamingUrl);
        progressDialog.dismiss();
        if (streamingUrl != null) {
            if (!streamingUrl.isEmpty()) {
                //Log.e("Steaming Url", "Value : " + streamingUrl);

                for (int i = 0; i < streamingUrl.size(); i++) {
                    Video fX = streamingUrl.get(i);
                    Log.e("Founded Video", "URL : " + fX.url);
                    Log.e("Founded Video", "TYPE : " + fX.type);
                    Log.e("Founded Video", "EXT : " + fX.ext);
                }
                //new ProgressBack().execute(new String[]{streamingUrl, filename + "." + ext});
            }
        }
    }
}
public void initTypeMap()
{
    typeMap.put("13", new Meta("13", "3GP", "Low Quality - 176x144"));
    typeMap.put("17", new Meta("17", "3GP", "Medium Quality - 176x144"));
    typeMap.put("36", new Meta("36", "3GP", "High Quality - 320x240"));
    typeMap.put("5", new Meta("5", "FLV", "Low Quality - 400x226"));
    typeMap.put("6", new Meta("6", "FLV", "Medium Quality - 640x360"));
    typeMap.put("34", new Meta("34", "FLV", "Medium Quality - 640x360"));
    typeMap.put("35", new Meta("35", "FLV", "High Quality - 854x480"));
    typeMap.put("43", new Meta("43", "WEBM", "Low Quality - 640x360"));
    typeMap.put("44", new Meta("44", "WEBM", "Medium Quality - 854x480"));
    typeMap.put("45", new Meta("45", "WEBM", "High Quality - 1280x720"));
    typeMap.put("18", new Meta("18", "MP4", "Medium Quality - 480x360"));
    typeMap.put("22", new Meta("22", "MP4", "High Quality - 1280x720"));
    typeMap.put("37", new Meta("37", "MP4", "High Quality - 1920x1080"));
    typeMap.put("33", new Meta("38", "MP4", "High Quality - 4096x230"));
}

Edit 2:

Some time This Code Not worked proper

Same-origin policy

https://en.wikipedia.org/wiki/Same-origin_policy

https://en.wikipedia.org/wiki/Cross-origin_resource_sharing

problem of Same-origin policy. Essentially, you cannot download this file from www.youtube.com because they are different domains. A workaround of this problem is [CORS][1].

Ref : https://superuser.com/questions/773719/how-do-all-of-these-save-video-from-youtube-services-work/773998#773998

url_encoded_fmt_stream_map // traditional: contains video and audio stream
adaptive_fmts              // DASH: contains video or audio stream

Each of these is a comma separated array of what I would call "stream objects". Each "stream object" will contain values like this

url  // direct HTTP link to a video
itag // code specifying the quality
s    // signature, security measure to counter downloading

Each URL will be encoded so you will need to decode them. Now the tricky part.

YouTube has at least 3 security levels for their videos

unsecured // as expected, you can download these with just the unencoded URL
s         // see below
RTMPE     // uses "rtmpe://" protocol, no known method for these

The RTMPE videos are typically used on official full length movies, and are protected with SWF Verification Type 2. This has been around since 2011 and has yet to be reverse engineered.

The type "s" videos are the most difficult that can actually be downloaded. You will typcially see these on VEVO videos and the like. They start with a signature such as

AA5D05FA7771AD4868BA4C977C3DEAAC620DE020E.0F421820F42978A1F8EAFCDAC4EF507DB5 Then the signature is scrambled with a function like this

function mo(a) {
  a = a.split("");
  a = lo.rw(a, 1);
  a = lo.rw(a, 32);
  a = lo.IC(a, 1);
  a = lo.wS(a, 77);
  a = lo.IC(a, 3);
  a = lo.wS(a, 77);
  a = lo.IC(a, 3);
  a = lo.wS(a, 44);
  return a.join("")
}

This function is dynamic, it typically changes every day. To make it more difficult the function is hosted at a URL such as

http://s.ytimg.com/yts/jsbin/html5player-en_US-vflycBCEX.js

this introduces the problem of Same-origin policy. Essentially, you cannot download this file from www.youtube.com because they are different domains. A workaround of this problem is CORS. With CORS, s.ytimg.com could add this header

Access-Control-Allow-Origin: http://www.youtube.com

and it would allow the JavaScript to download from www.youtube.com. Of course they do not do this. A workaround for this workaround is to use a CORS proxy. This is a proxy that responds with the following header to all requests

Access-Control-Allow-Origin: *

So, now that you have proxied your JS file, and used the function to scramble the signature, you can use that in the querystring to download a video.

How to remove duplicates from Python list and keep order?

A list can be sorted and deduplicated using built-in functions:

myList = sorted(set(myList))

set is a built-in function for Python >= 2.3
sorted is a built-in function for Python >= 2.4

How to save picture to iPhone photo library?

You can use this

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
   UIImageWriteToSavedPhotosAlbum(img.image, nil, nil, nil);
});

Eclipse error: 'Failed to create the Java Virtual Machine'

In STS.conf file you need to check two important things to avoid create/allocate jvm issue

1. Give the exact jdk install location:

--vm C:\Program Files\Java\jdk1.7.0_01\jre\bin\javaw.exe

2. You need to give the exact java installed version:

--Dosgi.requiredJavaVersion=1.7

3. Try to reduce the memory size:

--XX:MaxPermSize=256m

Angularjs prevent form submission when input validation fails

So the suggested answer from TheHippo did not work for me, instead I ended up sending the form as a parameter to the function like so:

<form name="loginform" novalidate ng-submit="login.submit(loginForm)" class="css-form">

This makes the form available in the controller method:

$scope.login = {
    submit : function(form) {
        if(form.$valid)....
    }

How can I turn a string into a list in Python?

The list() function ^[docs] will convert a string into a list of single-character strings.

>>> list('hello')
['h', 'e', 'l', 'l', 'o']

Even without converting them to lists, strings already behave like lists in several ways. For example, you can access individual characters (as single-character strings) using brackets:

>>> s = "hello"
>>> s[1]
'e'
>>> s[4]
'o'

You can also loop over the characters in the string as you can loop over the elements of a list:

>>> for c in 'hello':
...     print c + c,
... 
hh ee ll ll oo

Why is HttpClient BaseAddress not working?

Reference Resolution is described by RFC 3986 Uniform Resource Identifier (URI): Generic Syntax. And that is exactly how it supposed to work. To preserve base URI path you need to add slash at the end of the base URI and remove slash at the beginning of relative URI.

If base URI contains non-empty path, merge procedure discards it's last part (after last /). Relevant section:

5.2.3. Merge Paths

The pseudocode above refers to a "merge" routine for merging a relative-path reference with the path of the base URI. This is accomplished as follows:

If the base URI has a defined authority component and an empty path, then return a string consisting of "/" concatenated with the reference's path; otherwise

return a string consisting of the reference's path component appended to all but the last segment of the base URI's path (i.e., excluding any characters after the right-most "/" in the base URI path, or excluding the entire base URI path if it does not contain any "/" characters).

If relative URI starts with a slash, it is called a absolute-path relative URI. In this case merge procedure ignore all base URI path. For more information check 5.2.2. Transform References section.

How do I create a HTTP Client Request with a cookie?

This answer is deprecated, please see @ankitjaininfo's answer below for a more modern solution

Here's how I think you make a POST request with data and a cookie using just the node http library. This example is posting JSON, set your content-type and content-length accordingly if you post different data.

// NB:- node's http client API has changed since this was written
// this code is for 0.4.x
// for 0.6.5+ see http://nodejs.org/docs/v0.6.5/api/http.html#http.request

var http = require('http');

var data = JSON.stringify({ 'important': 'data' });
var cookie = 'something=anything'

var client = http.createClient(80, 'www.example.com');

var headers = {
    'Host': 'www.example.com',
    'Cookie': cookie,
    'Content-Type': 'application/json',
    'Content-Length': Buffer.byteLength(data,'utf8')
};

var request = client.request('POST', '/', headers);

// listening to the response is optional, I suppose
request.on('response', function(response) {
  response.on('data', function(chunk) {
    // do what you do
  });
  response.on('end', function() {
    // do what you do
  });
});
// you'd also want to listen for errors in production

request.write(data);

request.end();

What you send in the Cookie value should really depend on what you received from the server. Wikipedia's write-up of this stuff is pretty good: http://en.wikipedia.org/wiki/HTTP_cookie#Cookie_attributes

How to get selected path and name of the file opened with file dialog?

I think you want this:

Dim filename As String
filename = Application.GetOpenFilename

Dim cell As Range
cell = Application.Range("A1")
cell.Value = filename

groovy.lang.MissingPropertyException: No such property: jenkins for class: groovy.lang.Binding

Please double check that jenkins is not blocking this import. Go to script approvals and check to see if it is blocking it. If it is click allow.

https://jenkins.io/doc/book/managing/script-approval/

add title attribute from css

You can't. CSS is a presentation language. It isn't designed to add content (except for the very trivial with :before and :after).

java.net.ConnectException: localhost/127.0.0.1:8080 - Connection refused

Add Internet permission in Androidmanifest.xml file

uses-permission android:name="android.permission.INTERNET

Open cmd in windows
type "ipconfig" then press enter
find IPv4 Address. . . . . . . . . . . : 192.168.X.X
use this URL "http://192.168.X.X:your_virtual_server_port/your_service.php"

Not showing placeholder for input type="date" field

It works for me:

input[type='date']:after {
  content: attr(placeholder)
}

How to select an element with 2 classes

You can chain class selectors without a space between them:

.a.b {
     color: #666;
}

Note that, if it matters to you, IE6 treats .a.b as .b, so in that browser both div.a.b and div.b will have gray text. See this answer for a comparison between proper browsers and IE6.

how to set radio button checked in edit mode in MVC razor view

To set radio button checked in edit mode in MVC razor view, please trying as follow:

<div class="col-lg-11 col-md-11">
     @Html.RadioButtonFor(m => m.Role, "1", Model.Role == 1 ? "checked" : string.Empty) 
     <span>Admin</span>
     @Html.RadioButtonFor(m => m.Role, "0", Model.Role == 0 ? "checked" : string.Empty)
     <span>User</span>
     @Html.HiddenFor(m => m.Role)
</div>

Hope it help!

Javascript Array inside Array - how can I call the child array name?

You've made an array of arrays (multidimensional), so options[0] in this case is the size array. you need to reference the first element of the child, which for you is: options[0][0].

If you wanted to loop through all entries you can use the for .. in ... syntax which is described here.

var a = [1,2,4,5,120,12];
for (var val in t) {
    console.log(t[val]);
}

var b = ['S','M','L'];
var both = [a,b];

for (var val in both) {
     for(val2 in both[val]){console.log(both[val][val2])}
}

Ant if else condition?

Since ant 1.9.1 you can use a if:set condition : https://ant.apache.org/manual/ifunless.html

What is the difference between JAX-RS and JAX-WS?

Can JAX-RS do Asynchronous Request like JAX-WS?

1) I don't know if the JAX-RS API includes a specific mechanism for asynchronous requests, but this answer could still change based on the client implementation you use.

Can JAX-RS access a web service that is not running on the Java platform, and vice versa?

2) I can't think of any reason it wouldn't be able to.

What does it mean by "REST is particularly useful for limited-profile devices, such as PDAs and mobile phones"?

3) REST based architectures typically will use a lightweight data format, like JSON, to send data back and forth. This is in contrast to JAX-WS which uses XML. I don't see XML by itself so significantly heavier than JSON (which some people may argue), but with JAX-WS it's how much XML is used that ends up making REST with JSON the lighter option.

What does it mean by "JAX-RS do not require XML messages or WSDL service–API definitions?

4) As stated in 3, REST architectures often use JSON to send and receive data. JAX-WS uses XML. It's not that JSON is so significantly smaller than XML by itself. It's mostly that JAX-WS specification includes lots overhead in how it communicates.

On the point about WSDL and API definitions, REST will more frequently use the URI structure and HTTP commands to define the API rather than message types, as is done in the JAX-WS. This means that you don't need to publish a WSDL document so that other users of your service can know how to talk to your service. With REST you will still need to provide some documentation to other users about how the REST service is organized and what data and HTTP commands need to be sent.

Why doesn't Python have a sign function?

Only correct answer compliant with the Wikipedia definition

The definition on Wikipedia reads:

$sign definition$

Hence,

sign = lambda x: -1 if x < 0 else (1 if x > 0 else (0 if x == 0 else NaN))

Which for all intents and purposes may be simplified to:

sign = lambda x: -1 if x < 0 else (1 if x > 0 else 0)

This function definition executes fast and yields guaranteed correct results for 0, 0.0, -0.0, -4 and 5 (see comments to other incorrect answers).

Note that zero (0) is neither positive nor negative.

Android setOnClickListener method - How does it work?

It works by same principle of anonymous inner class where we can instantiate an interface without actually defining a class :

Ref: https://www.geeksforgeeks.org/anonymous-inner-class-java/

Javascript for "Add to Home Screen" on iPhone?

There is an open source Javascript library that offers something related : mobile-bookmark-bubble

The Mobile Bookmark Bubble is a JavaScript library that adds a promo bubble to the bottom of your mobile web application, inviting users to bookmark the app to their device's home screen. The library uses HTML5 local storage to track whether the promo has been displayed already, to avoid constantly nagging users.

The current implementation of this library specifically targets Mobile Safari, the web browser used on iPhone and iPad devices.

xcode-select active developer directory error

This problem happens when xcode-select developer directory was pointing to /Library/Developer/CommandLineTools when a full regular Xcode was required (happens when CommandLineTools are installed after Xcode)

Solution:

Install Xcode (get it from https://appstore.com/mac/apple/xcode) if you don't have it yet.
Accept the Terms and Conditions.
Ensure Xcode app is in the /Applications directory (NOT /Users/{user}/Applications).
Point xcode-select to the Xcode app Developer directory using the following command:
sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

Note: Make sure your Xcode app path is correct.

Xcode: /Applications/Xcode.app/Contents/Developer
Xcode-beta: /Applications/Xcode-beta.app/Contents/Developer

nil detection in Go

In Go 1.13 and later, you can use Value.IsZero method offered in reflect package.

if reflect.ValueOf(v).IsZero() {
    // v is zero, do something
}

Apart from basic types, it also works for Array, Chan, Func, Interface, Map, Ptr, Slice, UnsafePointer, and Struct. See this for reference.

How to compare only Date without Time in DateTime types in Linq to SQL with Entity Framework?

You can use Equals or CompareTo.

Equals: Returns a value indicating whether two DateTime instances have the same date and time value.

CompareTo Return Value:

Less than zero : If this instance is earlier than value.
Zero : If this instance is the same as value.
Greater than zero : If this instance is later than value.

DateTime is nullable:

DateTime? first = new DateTime(1992,02,02,20,50,1);
DateTime? second = new DateTime(1992, 02, 02, 20, 50, 2);

if (first.Value.Date.Equals(second.Value.Date))
{
    Console.WriteLine("Equal");
}

DateTime? first = new DateTime(1992,02,02,20,50,1);
DateTime? second = new DateTime(1992, 02, 02, 20, 50, 2);


var compare = first.Value.Date.CompareTo(second.Value.Date);

switch (compare)
{
    case 1:
        Console.WriteLine("this instance is later than value.");
        break;
    case 0:
        Console.WriteLine("this instance is the same as value.");
        break;
    default:
        Console.WriteLine("this instance is earlier than value.");
        break;
}

DateTime is not nullable:

DateTime first = new DateTime(1992,02,02,20,50,1);
DateTime second = new DateTime(1992, 02, 02, 20, 50, 2);

if (first.Date.Equals(second.Date))
{
    Console.WriteLine("Equal");
}

DateTime first = new DateTime(1992,02,02,20,50,1);
DateTime second = new DateTime(1992, 02, 02, 20, 50, 2);


var compare = first.Date.CompareTo(second.Date);

switch (compare)
{
    case 1:
        Console.WriteLine("this instance is later than value.");
        break;
    case 0:
        Console.WriteLine("this instance is the same as value.");
        break;
    default:
        Console.WriteLine("this instance is earlier than value.");
        break;
}

Iterate through Nested JavaScript Objects

The following code assumes no circular references, and assumes subs is always an array (and not null in leaf nodes):

function find(haystack, needle) {
  if (haystack.label === needle) return haystack;
  for (var i = 0; i < haystack.subs.length; i ++) {
    var result = find(haystack.subs[i], needle);
    if (result) return result;
  }
  return null;
}

Private Variables and Methods in Python

The double underscore. It mangles the name in such a way that it can't be accessed simply through __fieldName from outside the class, which is what you want to begin with if they're to be private. (Though it's still not very hard to access the field.)

class Foo:
    def __init__(self):
        self.__privateField = 4;
        print self.__privateField # yields 4 no problem

foo = Foo()
foo.__privateField
# AttributeError: Foo instance has no attribute '__privateField'

It will be accessible through _Foo__privateField instead. But it screams "I'M PRIVATE DON'T TOUCH ME", which is better than nothing.

Why is enum class preferred over plain enum?

Enumerations are used to represent a set of integer values.

The class keyword after the enum specifies that the enumeration is strongly typed and its enumerators are scoped. This way enum classes prevents accidental misuse of constants.

For Example:

enum class Animal{Dog, Cat, Tiger};
enum class Pets{Dog, Parrot};

Here we can not mix Animal and Pets values.

Animal a = Dog;       // Error: which DOG?    
Animal a = Pets::Dog  // Pets::Dog is not an Animal

"getaddrinfo failed", what does that mean?

Make sure you pass a proxy attribute in your command forexample - pip install --proxy=http://proxyhost:proxyport pixiedust

Use a proxy port which has direct connection (with / without password). Speak with your corporate IT administrator. Quick way is find out network settings used in eclipse which will have direct connection.

You will encouter this issue often if you work behind a corporate firewall. You will have to check your internet explorer - InternetOptions -LAN Connection - Settings

Uncheck - Use automatic configuration script Check - Use a proxy server for your LAN. Ensure you have given the right address and port.

Click Ok Come back to anaconda terminal and you can try install commands

Can I return the 'id' field after a LINQ insert?

After you commit your object into the db the object receives a value in its ID field.

So:

myObject.Field1 = "value";

// Db is the datacontext
db.MyObjects.InsertOnSubmit(myObject);
db.SubmitChanges();

// You can retrieve the id from the object
int id = myObject.ID;

How do I use reflection to invoke a private method?

Are you absolutely sure this can't be done through inheritance? Reflection is the very last thing you should look at when solving a problem, it makes refactoring, understanding your code, and any automated analysis more difficult.

It looks like you should just have a DrawItem1, DrawItem2, etc class that override your dynMethod.

Is it possible to ORDER results with query or scan in DynamoDB?

How to trim a list in Python

To trim a list in place without creating copies of it, use del:

>>> t = [1, 2, 3, 4, 5]
>>> # delete elements starting from index 4 to the end
>>> del t[4:]
>>> t
[1, 2, 3, 4]
>>> # delete elements starting from index 5 to the end
>>> # but the list has only 4 elements -- no error
>>> del t[5:]
>>> t
[1, 2, 3, 4]
>>>

What to put in a python module docstring?

Think about somebody doing help(yourmodule) at the interactive interpreter's prompt — what do they want to know? (Other methods of extracting and displaying the information are roughly equivalent to help in terms of amount of information). So if you have in x.py:

"""This module does blah blah."""

class Blah(object):
  """This class does blah blah."""

then:

>>> import x; help(x)

shows:

Help on module x:

NAME
    x - This module does blah blah.

FILE
    /tmp/x.py

CLASSES
    __builtin__.object
        Blah

    class Blah(__builtin__.object)
     |  This class does blah blah.
     |  
     |  Data and other attributes defined here:
     |  
     |  __dict__ = <dictproxy object>
     |      dictionary for instance variables (if defined)
     |  
     |  __weakref__ = <attribute '__weakref__' of 'Blah' objects>
     |      list of weak references to the object (if defined)

As you see, the detailed information on the classes (and functions too, though I'm not showing one here) is already included from those components' docstrings; the module's own docstring should describe them very summarily (if at all) and rather concentrate on a concise summary of what the module as a whole can do for you, ideally with some doctested examples (just like functions and classes ideally should have doctested examples in their docstrings).

I don't see how metadata such as author name and copyright / license helps the module's user — it can rather go in comments, since it could help somebody considering whether or not to reuse or modify the module.

How to create .ipa file using Xcode?

Archive process (using Xcode 8.3.2)

Note : If you are using creating IPA using drag-and-drop process using iTunes Mac app then this is no longer applicable for iTunes 12.7 since there is no built-in App store in iTunes 12.7.

Select ‘Generic iOS Device’ on device list in Xcode

Clean the project (cmd + shift + k as shortcut)

Go to Product -> Archive your project

Once archive is succeeded this will open a window with archived project
You can validate your archive by pressing Validate (optional step but recommended)
Now press on Export button

This will open list of method for export. Select the export method as per your requirement and click on Next button.

This will show list of team for provisioning. Select accordingly and press on ‘Choose’ button.

Now you’ve to select Device support -> Export one app for all compatible devices (recommended). If you want IPA for specific device then select the device variant from list and press on ‘Next’ button.

Now you’ll be able to see the ‘Summary’ and then press on ‘Next’ button

Thereafter IPA file generation beings and later you’ll be able to export the IPA as [App Name - Date Time] and then press on ‘Done’.

simple vba code gives me run time error 91 object variable or with block not set

Also you are trying to set value2 using Set keyword, which is not required. You can directly use rng.value2 = 1

below test code for ref.

Sub test()
    Dim rng As Range
    Set rng = Range("A1")
    rng.Value2 = 1
End Sub

How do I create a basic UIButton programmatically?

UIButton *addProject = [UIButton buttonWithType: UIButtonTypeRoundedRect];
addProject.frame = CGRectMake(210, 285, 100, 18);
[addProject setTitle:@"Show View" forState:UIControlStateNormal];
[addProject addTarget:self action:@selector(addProjectPressed:) forControlEvents:UIControlEventTouchUpInside];
[_scrollView addSubview:addProject];

When should I use GET or POST method? What's the difference between them?

When the user enters information in a form and clicks Submit , there are two ways the information can be sent from the browser to the server: in the URL, or within the body of the HTTP request.

The GET method, which was used in the example earlier, appends name/value pairs to the URL. Unfortunately, the length of a URL is limited, so this method only works if there are only a few parameters. The URL could be truncated if the form uses a large number of parameters, or if the parameters contain large amounts of data. Also, parameters passed on the URL are visible in the address field of the browser not the best place for a password to be displayed.

The alternative to the GET method is the POST method. This method packages the name/value pairs inside the body of the HTTP request, which makes for a cleaner URL and imposes no size limitations on the forms output. It is also more secure.

Returning first x items from array

A more object oriented way would be to provide a range to the #[] method. For instance:

Say you want the first 3 items from an array.

numbers = [1,2,3,4,5,6]

numbers[0..2] # => [1,2,3]

Say you want the first x items from an array.

numbers[0..x-1]

The great thing about this method is if you ask for more items than the array has, it simply returns the entire array.

numbers[0..100] # => [1,2,3,4,5,6]

How to get jSON response into variable from a jquery script

You should use data.response in your JS instead of json.response.

Algorithm to return all combinations of k elements from n

We can use the concept of bits to do this. Let we have a string of "abc," and we want to have all combinations of the elements with length 2 (i.e "ab" , "ac","bc".)

We can find the set bits in numbers ranging from 1 to 2^n (exclusive). Here 1 to 7, and wherever we have set bits = 2, we can print the corresponding value from string.

for example:

1 - 001
2 - 010
3 - 011 -> print ab (str[0] , str[1])
4 - 100
5 - 101 -> print ac (str[0] , str[2])
6 - 110 -> print ab (str[1] , str[2])
7 - 111.

Code sample:

public class StringCombinationK {   
    static void combk(String s , int k){
        int n = s.length();
        int num = 1<<n;
        int j=0;
        int count=0;

        for(int i=0;i<num;i++){
            if (countSet(i)==k){
                setBits(i,j,s);
                count++;
                System.out.println();
            }
        }

        System.out.println(count);
    }

    static void setBits(int i,int j,String s){ // print the corresponding string value,j represent the index of set bit
        if(i==0){
            return;
        }

        if(i%2==1){
            System.out.print(s.charAt(j));                  
        }

        setBits(i/2,j+1,s);
    }

    static int countSet(int i){ //count number of set bits
        if( i==0){
            return 0;
        }

        return (i%2==0? 0:1) + countSet(i/2);
    }

    public static void main(String[] arhs){
        String s = "abcdefgh";
        int k=3;
        combk(s,k);
    }
}

Finding moving average from data points in Python

ravgs = [sum(data[i:i+5])/5. for i in range(len(data)-4)]

This isn't the most efficient approach but it will give your answer and I'm unclear if your window is 5 points or 10. If its 10, replace each 5 with 10 and the 4 with 9.

How to hide code from cells in ipython notebook visualized with nbviewer?

This will render an IPython notebook output. However, you will note be able to view the input code. You can copy a notebook, then add this code if needed to share with someone who does not need to view the code.

from IPython.display import HTML

HTML('''<script> $('div .input').hide()''')

How to run Conda?

For Windows:

PATH=%USERPROFILE%\Continuum\Anaconda4.4.0\Library\bin;%PATH%

How to speed up insertion performance in PostgreSQL

For optimal Insertion performance disable the index if that's an option for you. Other than that, better hardware (disk, memory) is also helpful

How to run a cronjob every X minutes?

2 steps to check if a cronjob is working :

Login on the server with the user that execute the cronjob
Manually run php command :

/usr/bin/php /mydomain.in/cromail.php

And check if any error is displayed

Use .htaccess to redirect HTTP to HTTPs

None if this worked for me. First of all I had to look at my provider to see how they activate SSL in .htaccess my provider gives

<IfModule mod_rewrite.c>
   RewriteEngine On
   RewriteCond %{HTTP:HTTPS} !on
   RewriteRule (.*) https://%{SERVER_NAME}/$1 [QSA,L,R=301]
</IfModule>

But what took me days of research is I had to add to wp-config.php the following lines as my provided site is behind a proxy :

/**
 * Force le SSL
 */
define('FORCE_SSL_ADMIN', true);
if (strpos($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') !== false) $_SERVER['HTTPS']='on';

How to restart VScode after editing extension's config?

Execute the workbench.action.reloadWindow command.

There are some ways to do so:

Open the command palette (Ctrl + Shift + P) and execute the command:
```
>Reload Window    
```

Define a keybinding for the command (for example CTRL+F5) in keybindings.json:

[
  {
    "key": "ctrl+f5",
    "command": "workbench.action.reloadWindow",
    "when": "editorTextFocus"
  }
]

Difference between Activity and FragmentActivity

FragmentActivity is part of the support library, while Activity is the framework's default class. They are functionally equivalent.

You should always use FragmentActivity and android.support.v4.app.Fragment instead of the platform default Activity and android.app.Fragment classes. Using the platform defaults mean that you are relying on whatever implementation of fragments is used in the device you are running on. These are often multiple years old, and contain bugs that have since been fixed in the support library.

any tool for java object to object mapping?

ModelMapper is another library worth checking out. ModelMapper's design is different from other libraries in that it:

Automatically maps object models by intelligently matching source and destination properties
Provides a refactoring safe mapping API that uses actual code to map fields and methods rather than using strings
Utilizes convention based configuration for simple handling of custom scenarios

Check out the ModelMapper site for more info:

http://modelmapper.org

HTML5 File API read as text and binary

Note in 2018: readAsBinaryString is outdated. For use cases where previously you'd have used it, these days you'd use readAsArrayBuffer (or in some cases, readAsDataURL) instead.

readAsBinaryString says that the data must be represented as a binary string, where:

...every byte is represented by an integer in the range [0..255].

JavaScript originally didn't have a "binary" type (until ECMAScript 5's WebGL support of Typed Array* (details below) -- it has been superseded by ECMAScript 2015's ArrayBuffer) and so they went with a String with the guarantee that no character stored in the String would be outside the range 0..255. (They could have gone with an array of Numbers instead, but they didn't; perhaps large Strings are more memory-efficient than large arrays of Numbers, since Numbers are floating-point.)

If you're reading a file that's mostly text in a western script (mostly English, for instance), then that string is going to look a lot like text. If you read a file with Unicode characters in it, you should notice a difference, since JavaScript strings are UTF-16** (details below) and so some characters will have values above 255, whereas a "binary string" according to the File API spec wouldn't have any values above 255 (you'd have two individual "characters" for the two bytes of the Unicode code point).

If you're reading a file that's not text at all (an image, perhaps), you'll probably still get a very similar result between readAsText and readAsBinaryString, but with readAsBinaryString you know that there won't be any attempt to interpret multi-byte sequences as characters. You don't know that if you use readAsText, because readAsText will use an encoding determination to try to figure out what the file's encoding is and then map it to JavaScript's UTF-16 strings.

You can see the effect if you create a file and store it in something other than ASCII or UTF-8. (In Windows you can do this via Notepad; the "Save As" as an encoding drop-down with "Unicode" on it, by which looking at the data they seem to mean UTF-16; I'm sure Mac OS and *nix editors have a similar feature.) Here's a page that dumps the result of reading a file both ways:

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-type" content="text/html;charset=UTF-8">
<title>Show File Data</title>
<style type='text/css'>
body {
    font-family: sans-serif;
}
</style>
<script type='text/javascript'>

    function loadFile() {
        var input, file, fr;

        if (typeof window.FileReader !== 'function') {
            bodyAppend("p", "The file API isn't supported on this browser yet.");
            return;
        }

        input = document.getElementById('fileinput');
        if (!input) {
            bodyAppend("p", "Um, couldn't find the fileinput element.");
        }
        else if (!input.files) {
            bodyAppend("p", "This browser doesn't seem to support the `files` property of file inputs.");
        }
        else if (!input.files[0]) {
            bodyAppend("p", "Please select a file before clicking 'Load'");
        }
        else {
            file = input.files[0];
            fr = new FileReader();
            fr.onload = receivedText;
            fr.readAsText(file);
        }

        function receivedText() {
            showResult(fr, "Text");

            fr = new FileReader();
            fr.onload = receivedBinary;
            fr.readAsBinaryString(file);
        }

        function receivedBinary() {
            showResult(fr, "Binary");
        }
    }

    function showResult(fr, label) {
        var markup, result, n, aByte, byteStr;

        markup = [];
        result = fr.result;
        for (n = 0; n < result.length; ++n) {
            aByte = result.charCodeAt(n);
            byteStr = aByte.toString(16);
            if (byteStr.length < 2) {
                byteStr = "0" + byteStr;
            }
            markup.push(byteStr);
        }
        bodyAppend("p", label + " (" + result.length + "):");
        bodyAppend("pre", markup.join(" "));
    }

    function bodyAppend(tagName, innerHTML) {
        var elm;

        elm = document.createElement(tagName);
        elm.innerHTML = innerHTML;
        document.body.appendChild(elm);
    }

</script>
</head>
<body>
<form action='#' onsubmit="return false;">
<input type='file' id='fileinput'>
<input type='button' id='btnLoad' value='Load' onclick='loadFile();'>
</form>
</body>
</html>

If I use that with a "Testing 1 2 3" file stored in UTF-16, here are the results I get:

Text (13):

54 65 73 74 69 6e 67 20 31 20 32 20 33

Binary (28):

ff fe 54 00 65 00 73 00 74 00 69 00 6e 00 67 00 20 00 31 00 20 00 32 00 20 00 33 00

As you can see, readAsText interpreted the characters and so I got 13 (the length of "Testing 1 2 3"), and readAsBinaryString didn't, and so I got 28 (the two-byte BOM plus two bytes for each character).

* XMLHttpRequest.response with responseType = "arraybuffer" is supported in HTML 5.

** "JavaScript strings are UTF-16" may seem like an odd statement; aren't they just Unicode? No, a JavaScript string is a series of UTF-16 code units; you see surrogate pairs as two individual JavaScript "characters" even though, in fact, the surrogate pair as a whole is just one character. See the link for details.

Display a RecyclerView in Fragment

This was asked some time ago now, but based on the answer that @nacho_zona3 provided, and previous experience with fragments, the issue is that the views have not been created by the time you are trying to find them with the findViewById() method in onCreate() to fix this, move the following code:

// 1. get a reference to recyclerView
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.list);

// 2. set layoutManger
recyclerView.setLayoutManager(new LinearLayoutManager(this));

// this is data fro recycler view
ItemData itemsData[] = { new ItemData("Indigo",R.drawable.circle),
        new ItemData("Red",R.drawable.color_ic_launcher),
        new ItemData("Blue",R.drawable.indigo),
        new ItemData("Green",R.drawable.circle),
        new ItemData("Amber",R.drawable.color_ic_launcher),
        new ItemData("Deep Orange",R.drawable.indigo)};


// 3. create an adapter
MyAdapter mAdapter = new MyAdapter(itemsData);
// 4. set adapter
recyclerView.setAdapter(mAdapter);
// 5. set item animator to DefaultAnimator
recyclerView.setItemAnimator(new DefaultItemAnimator());

to your fragment's onCreateView() call. A small amount of refactoring is required because all variables and methods called from this method have to be static. The final code should look like:

 public class ColorsFragment extends Fragment {

     public ColorsFragment() {}

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

         View rootView = inflater.inflate(R.layout.fragment_colors, container, false);
         // 1. get a reference to recyclerView
         RecyclerView recyclerView = (RecyclerView) rootView.findViewById(R.id.list);

         // 2. set layoutManger
         recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

         // this is data fro recycler view
         ItemData itemsData[] = {
             new ItemData("Indigo", R.drawable.circle),
                 new ItemData("Red", R.drawable.color_ic_launcher),
                 new ItemData("Blue", R.drawable.indigo),
                 new ItemData("Green", R.drawable.circle),
                 new ItemData("Amber", R.drawable.color_ic_launcher),
                 new ItemData("Deep Orange", R.drawable.indigo)
         };


         // 3. create an adapter
         MyAdapter mAdapter = new MyAdapter(itemsData);
         // 4. set adapter
         recyclerView.setAdapter(mAdapter);
         // 5. set item animator to DefaultAnimator
         recyclerView.setItemAnimator(new DefaultItemAnimator());

         return rootView;
     }
 }

So the main thing here is that anywhere you call findViewById() you will need to use rootView.findViewById()

How to colorize diff on the command line?

Coloured, word-level diff ouput

Here's what you can do with the the below script and diff-highlight:

#!/bin/sh -eu

# Use diff-highlight to show word-level differences

diff -U3 --minimal "$@" |
  sed 's/^-/\x1b[1;31m-/;s/^+/\x1b[1;32m+/;s/^@/\x1b[1;34m@/;s/$/\x1b[0m/' |
  diff-highlight

_{(Credit to @retracile's answer for the sed highlighting)}

How to improve a case statement that uses two columns

You could do it this way:

-- Notice how STATE got moved inside the condition:
CASE WHEN STATE = 2 AND RetailerProcessType IN (1, 2) THEN '"AUTHORISED"'
     WHEN STATE = 1 AND RetailerProcessType = 2 THEN '"PENDING"'
     ELSE '"DECLINED"'
END

The reason you can do an AND here is that you are not checking the CASE of STATE, but instead you are CASING Conditions.

The key part here is that the STATE condition is a part of the WHEN.

Android: Quit application when press back button

In my understanding Google wants Android to handle memory management and shutting down the apps. If you must exit the app from code, it might be beneficial to ask Android to run garbage collector.

@Override
public void onBackPressed(){
    System.gc();
    System.exit(0);
}

You can also add finish() to the code, but it is probably redundant, if you also do System.exit(0)

How to tell PowerShell to wait for each command to end before starting the next?

Besides using Start-Process -Wait, piping the output of an executable will make Powershell wait. Depending on the need, I will typically pipe to Out-Null, Out-Default, Out-String or Out-String -Stream. Here is a long list of some other output options.

# Saving output as a string to a variable.
$output = ping.exe example.com | Out-String

# Filtering the output.
ping stackoverflow.com | where { $_ -match '^reply' }

# Using Start-Process affords the most control.
Start-Process -Wait SomeExecutable.com

I do miss the CMD/Bash style operators that you referenced (&, &&, ||). It seems we have to be more verbose with Powershell.

JQuery/Javascript: check if var exists

It is impossible to determine whether a variable has been declared or not other than using try..catch to cause an error if it hasn't been declared. Test like:

if (typeof varName == 'undefined')

do not tell you if varName is a variable in scope, only that testing with typeof returned undefined. e.g.

var foo;
typeof foo == 'undefined'; // true
typeof bar == 'undefined'; // true

In the above, you can't tell that foo was declared but bar wasn't. You can test for global variables using in:

var global = this;
...
'bar' in global;  // false

But the global object is the only variable object* you can access, you can't access the variable object of any other execution context.

The solution is to always declare variables in an appropriate context.

The global object isn't really a variable object, it just has properties that match global variables and provide access to them so it just appears to be one.

socket.shutdown vs socket.close

it's mentioned right in the Socket Programming HOWTO (py2/py3)

Disconnecting

Strictly speaking, you’re supposed to use shutdown on a socket before you close it. The shutdown is an advisory to the socket at the other end. Depending on the argument you pass it, it can mean “I’m not going to send anymore, but I’ll still listen”, or “I’m not listening, good riddance!”. Most socket libraries, however, are so used to programmers neglecting to use this piece of etiquette that normally a close is the same as shutdown(); close(). So in most situations, an explicit shutdown is not needed.

...

How to change TIMEZONE for a java.util.Calendar/Date

The class Date/Timestamp represents a specific instant in time, with millisecond precision, since January 1, 1970, 00:00:00 GMT. So this time difference (from epoch to current time) will be same in all computers across the world with irrespective of Timezone.
Date/Timestamp doesn't know about the given time is on which timezone.
If we want the time based on timezone we should go for the Calendar or SimpleDateFormat classes in java.
If you try to print a Date/Timestamp object using toString(), it will convert and print the time with the default timezone of your machine.
So we can say (Date/Timestamp).getTime() object will always have UTC (time in milliseconds)
To conclude Date.getTime() will give UTC time, but toString() is on locale specific timezone, not UTC.

Now how will I create/change time on specified timezone?

The below code gives you a date (time in milliseconds) with specified timezones. The only problem here is you have to give date in string format.

   DateFormat dateFormat = new SimpleDateFormat("yyyyMMdd HH:mm:ss");
   dateFormatLocal.setTimeZone(timeZone);
   java.util.Date parsedDate = dateFormatLocal.parse(date);

Use dateFormat.format for taking input Date (which is always UTC), timezone and return date as String.

How to store UTC/GMT time in DB:

If you print the parsedDate object, the time will be in default timezone. But you can store the UTC time in DB like below.

        Calendar calGMT = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
        Timestamp tsSchedStartTime = new Timestamp (parsedDate.getTime());
        if (tsSchedStartTime != null) {
            stmt.setTimestamp(11, tsSchedStartTime, calGMT );
        } else {
            stmt.setNull(11, java.sql.Types.DATE);
        }

What is the effect of extern "C" in C++?

In every C++ program, all non-static functions are represented in the binary file as symbols. These symbols are special text strings that uniquely identify a function in the program.

In C, the symbol name is the same as the function name. This is possible because in C no two non-static functions can have the same name.

Because C++ allows overloading and has many features that C does not — like classes, member functions, exception specifications - it is not possible to simply use the function name as the symbol name. To solve that, C++ uses so-called name mangling, which transforms the function name and all the necessary information (like the number and size of the arguments) into some weird-looking string processed only by the compiler and linker.

So if you specify a function to be extern C, the compiler doesn't performs name mangling with it and it can be directly accessed using its symbol name as the function name.

This comes handy while using dlsym() and dlopen() for calling such functions.

What's the source of Error: getaddrinfo EAI_AGAIN?

The OP's error specifies a host (my-store.myshopify.com). The error I encountered is the same in all respects except that no domain is specified.

My solution may help others who are drawn here by the title "Error: getaddrinfo EAI_AGAIN"

I encountered the error when trying to serve a NodeJs & VueJs app from a different VM from where the code was developed originally.

The file vue.config.js read :

 module.exports = {
   devServer: {
     host: 'tstvm01',
     port: 3030,
   },
 };

When served on the original machine the start up output is :

App running at:
- Local:   http://tstvm01:3030/ 
- Network: http://tstvm01:3030/

Using the same settings on a VM tstvm07 got me a very similar error to the one the OP describes:

 INFO  Starting development server...
 10% building modules 1/1 modules 0 activeevents.js:183                              
      throw er; // Unhandled 'error' event
      ^

Error: getaddrinfo EAI_AGAIN
    at Object._errnoException (util.js:1022:11)
    at errnoException (dns.js:55:15)
    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:92:26)

If it ain't already obvious, changing vue.config.js to read ...

 module.exports = {
   devServer: {
     host: 'tstvm07',
     port: 3030,
   },
 };

... solved the problem.

How can I find and run the keytool

If you installed visual studio with Xamarin/mobile development support, you'll have a java install here C:\Program Files\Android\jdk\microsoft_dist_openjdk_{version}\bin\, as was my case.

Setting the default ssh key location

If you are only looking to point to a different location for you identity file, the you can modify your ~/.ssh/config file with the following entry:

IdentityFile ~/.foo/identity

man ssh_config to find other config options.

htaccess <Directory> deny from all

You can also use RedirectMatch directive to deny access to a folder.

To deny access to a folder, you can use the following RedirectMatch in htaccess :

 RedirectMatch 403 ^/folder/?$

This will forbid an external access to /folder/ eg : http://example.com/folder/ will return a 403 forbidden error.

To deny access to everything inside the folder, You can use this :

RedirectMatch 403 ^/folder/.*$

This will block access to the entire folder eg : http://example.com/folder/anyURI will return a 403 error response to client.

How to install python3 version of package via pip on Ubuntu?

To install pip for python3 use should use pip3 instead of pip. To install python in ubuntu 18.08 bionic

sudo apt-get install python3.7

To install the required pip package in ubuntu

sudo apt-get install python3-pip

How to modify PATH for Homebrew?

There are many ways to update your path. Jun1st answer works great. Another method is to augment your .bash_profile to have:

export PATH="/usr/local/bin:/usr/local/sbin:~/bin:$PATH"

The line above places /usr/local/bin and /usr/local/sbin in front of your $PATH. Once you source your .bash_profile or start a new terminal you can verify your path by echo'ing it out.

$ echo $PATH
/usr/local/bin:/usr/local/sbin:/Users/<your account>/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin

Once satisfied with the result running $ brew doctor again should no longer produce your error.

This blog post helped me out in resolving issues I ran into. http://moncefbelyamani.com/how-to-install-xcode-homebrew-git-rvm-ruby-on-mac/

How can I create download link in HTML?

i know i am late but this is what i got after 1 hour of search

 <?php 
      $file = 'file.pdf';

    if (! file) {
        die('file not found'); //Or do something 
    } else {
       if(isset($_GET['file'])){  
        // Set headers
        header("Cache-Control: public");
        header("Content-Description: File Transfer");
        header("Content-Disposition: attachment; filename=$file");
        header("Content-Type: application/zip");
        header("Content-Transfer-Encoding: binary");
        // Read the file from disk
        readfile($file); }
    }

    ?>

and for downloadable link i did this

<a href="index.php?file=file.pdf">Download PDF</a>

how to download file in react js

I have the exact same problem, and here is the solution I make use of now: (Note, this seems ideal to me because it keeps the files closely tied to the SinglePageApplication React app, that loads from Amazon S3. So, it's like storing on S3, and in an application, that knows where it is in S3, relatively speaking.

Steps

3 steps:

Make use of file saver in project: npmjs/package/file-saver (npm install file-saver or something)
Place the file in your project You say it's in the components folder. Well, chances are if you've got web-pack it's going to try and minify it.(someone please pinpoint what webpack would do with an asset file in components folder), and so I don't think it's what you'd want. So, I suggest to place the asset into the public folder, under a resource or an asset name. Webpack doesn't touch the public folder and index.html and your resources get copied over in production build as is, where you may refer them as shown in next step.

Refer to the file in your project Sample code:

import FileSaver from 'file-saver';
FileSaver.saveAs(
    process.env.PUBLIC_URL + "/resource/file.anyType",
    "fileNameYouWishCustomerToDownLoadAs.anyType");

Source

Appendix

I also try Link component of react-router react-router-docs/Link. The zip file would download, and somehow would unzip properly. Generally, links have blue color, to inherit parent color scheme, simply add a prop like: style={color: inherit} or simply assign a class of your CSS library like button button-primary or something if you're Bootstrappin'
Other sage questions it's closely related to:

How can I put a ListView into a ScrollView without it collapsing?

Using a ListView to make it not scroll is extremely expensive and goes against the whole purpose of ListView. You should NOT do this. Just use a LinearLayout instead.

Check if a string contains a string in C++

You can also use the System namespace. Then you can use the contains method.

#include <iostream>
using namespace System;

int main(){
    String ^ wholeString = "My name is Malindu";

    if(wholeString->ToLower()->Contains("malindu")){
        std::cout<<"Found";
    }
    else{
        std::cout<<"Not Found";
    }
}

How do I search for an object by its ObjectId in the mongo console?

Not strange at all, people do this all the time. Make sure the collection name is correct (case matters) and that the ObjectId is exact.

Documentation is here

> db.test.insert({x: 1})

> db.test.find()                                               // no criteria
{ "_id" : ObjectId("4ecc05e55dd98a436ddcc47c"), "x" : 1 }      

> db.test.find({"_id" : ObjectId("4ecc05e55dd98a436ddcc47c")}) // explicit
{ "_id" : ObjectId("4ecc05e55dd98a436ddcc47c"), "x" : 1 }

> db.test.find(ObjectId("4ecc05e55dd98a436ddcc47c"))           // shortcut
{ "_id" : ObjectId("4ecc05e55dd98a436ddcc47c"), "x" : 1 }

Getting the Username from the HKEY_USERS values

Open Reg HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList\
make a loop to get all subkeys
the subkeys you are interested with are those started with [S-1-5-21-] which means user (see key name [ProfileImagePath] they are always started with a path c:\Users)
Those starting with [S-1-5-21-12] are all local users
Those starting with [S-1-5-21-13] are all network users [if joined to Domained network] that are previously logged on the machine.

adding to window.onload event?

There are basically two ways

store the previous value of window.onload so your code can call a previous handler if present before or after your code executes
using the addEventListener approach (that of course Microsoft doesn't like and requires you to use another different name).

The second method will give you a bit more safety if another script wants to use window.onload and does it without thinking to cooperation but the main assumption for Javascript is that all the scripts will cooperate like you are trying to do.

Note that a bad script that is not designed to work with other unknown scripts will be always able to break a page for example by messing with prototypes, by contaminating the global namespace or by damaging the dom.

unix diff side-to-side results?

From icdiff's homepage:

enter image description here

Your terminal can display color, but most diff tools don't make good use of it. By highlighting changes, icdiff can show you the differences between similar files without getting in the way. This is especially helpful for identifying and understanding small changes within existing lines.

Instead of trying to be a diff replacement for all circumstances, the goal of icdiff is to be a tool you can reach for to get a better picture of what changed when it's not immediately obvious from diff.

IMHO, its output is much more readable than diff -y.

Best way to pass parameters to jQuery's .load()

In the first case, the data are passed to the script via GET, in the second via POST.

http://docs.jquery.com/Ajax/load#urldatacallback

I don't think there are limits to the data size, but the completition of the remote call will of course take longer with great amount of data.

Java Package Does Not Exist Error

Are they in the right subdirectories?

If you put /usr/share/stuff on the class path, files defined with package org.name should be in /usr/share/stuff/org/name.

EDIT: If you don't already know this, you should probably read this: http://download.oracle.com/javase/1.5.0/docs/tooldocs/windows/classpath.html#Understanding

EDIT 2: Sorry, I hadn't realised you were talking of Java source files in /usr/share/stuff. Not only they need to be in the appropriate sub-directory, but you need to compile them. The .java files don't need to be on the classpath, but on the source path. (The generated .class files need to be on the classpath.)

You might get away with compiling them if they're not under the right directory structure, but they should be, or it will generate warnings at least. The generated class files will be in the right subdirectories (wherever you've specified -d if you have).

You should use something like javac -sourcepath .:/usr/share/stuff test.java, assuming you've put the .java files that were under /usr/share/stuff under /usr/share/stuff/org/name (or whatever is appropriate according to their package names).

Adding a guideline to the editor in Visual Studio

For those who use Visual Assist, vertical guidelines can be enabled from Display section in Visual Assist's options:

How to convert a String into an array of Strings containing one character each

Use toCharArray() method. It splits the string into an array of characters:

http://java.sun.com/j2se/1.5.0/docs/api/java/lang/String.html#toCharArray%28%29

String str = "aabbab";
char[] chs = str.toCharArray();

"And" and "Or" troubles within an IF statement

The problem is probably somewhere else. Try this code for example:

Sub test()

  origNum = "006260006"
  creditOrDebit = "D"

  If (origNum = "006260006" Or origNum = "30062600006") And creditOrDebit = "D" Then
    MsgBox "OK"
  End If

End Sub

And you will see that your Or works as expected. Are you sure that your ElseIf statement is executed (it will not be executed if any of the if/elseif before is true)?

Java: getMinutes and getHours

From the Javadoc for Date.getHours

As of JDK version 1.1, replaced by Calendar.get(Calendar.HOUR_OF_DAY)

So use

Calendar rightNow = Calendar.getInstance();
int hour = rightNow.get(Calendar.HOUR_OF_DAY);

and the equivalent for getMinutes.

Download file through an ajax call php

A very simple solution using jQuery:

on the client side:

$('.act_download_statement').click(function(e){
    e.preventDefault();
    form = $('#my_form');
    form.submit();
});

and on the server side, make sure you send back the correct Content-Type header, so the browser will know its an attachment and the download will begin.

Django - "no module named django.core.management"

It sounds like you do not have django installed. You should check the directory produced by this command:

python -c "from distutils.sysconfig import get_python_lib; print get_python_lib()"

To see if you have the django packages in there.

If there's no django folder inside of site-packages, then you do not have django installed (at least for that version of python).

It is possible you have more than one version of python installed and django is inside of another version. You can find out all the versions of python if you type python and then press TAB. Here are all the different python's I have.

$python
python            python2-config    python2.6         python2.7-config  pythonw2.5
python-config     python2.5         python2.6-config  pythonw           pythonw2.6
python2           python2.5-config  python2.7         pythonw2          pythonw2.7

You can do the above command for each version of python and look inside the site-packages directory of each to see if any of them have django installed. For example:

python2.5 -c "from distutils.sysconfig import get_python_lib; print get_python_lib()"
python2.6 -c "from distutils.sysconfig import get_python_lib; print get_python_lib()"

If you happen to find django inside of say python2.6, try your original command with

python2.6 manage.py ...

What is the best way to auto-generate INSERT statements for a SQL Server table?

You can use SSMS Tools Pack (available for SQL Server 2005 and 2008). It comes with a feature for generating insert statements.

http://www.ssmstoolspack.com/

ORA-00979 not a group by expression

If you do grouping by virtue of including GROUP BY clause, any expression in SELECT, which is not group function (or aggregate function or aggregated column) such as COUNT, AVG, MIN, MAX, SUM and so on (List of Aggregate functions) should be present in GROUP BY clause.

Example (correct way) (here employee_id is not group function (non-aggregated column), so it must appear in GROUP BY. By contrast, sum(salary) is a group function (aggregated column), so it is not required to appear in the GROUP BYclause.

   SELECT employee_id, sum(salary) 
   FROM employees
   GROUP BY employee_id;

Example (wrong way) (here employee_id is not group function and it does not appear in GROUP BY clause, which will lead to the ORA-00979 Error .

   SELECT employee_id, sum(salary) 
   FROM employees;

To correct you need to do one of the following :

Include all non-aggregated expressions listed in SELECT clause in the GROUP BY clause
Remove group (aggregate) function from SELECT clause.

CORS: Cannot use wildcard in Access-Control-Allow-Origin when credentials flag is true

This works for me in development but I can't advise that in production, it's just a different way of getting the job done that hasn't been mentioned yet but probably not the best. Anyway here goes:

You can get the origin from the request, then use that in the response header. Here's how it looks in express:

app.use(function(req, res, next) {
  res.header('Access-Control-Allow-Origin', req.header('origin') );
  next();
});

I don't know what that would look like with your python setup but that should be easy to translate.

How do I invoke a text editor from the terminal?

Command CompileSwift failed with a nonzero exit code in Xcode 10

I did the following and it works like charm:

Open Xcode Preferences (Command,)
Go to the Locations tab
Click on the small gray arrow which shows URL path for Derived Data
The finder window will open up and show the following folders:
- DerivedData
- Archives
- iOS DeviceSupport
- UserData
- DocumentationCache
- iOS Device Logs
Quit Xcode
Delete the DerivedData folder (it just contains a cache from previous builds)
Restart Xcode

CS0234: Mvc does not exist in the System.Web namespace

I tried all these answers, even closed Visual Studio and deleted all bin directories.

After starting it up again the MVC reference appeared to have a yellow exclamation mark on it, so I removed it and added it again.

Now it works, without copy local.

I am getting an "Invalid Host header" message when connecting to webpack-dev-server remotely

This is what worked for me:

Add allowedHosts under devServer in your webpack.config.js:

devServer: {
  compress: true,
  inline: true,
  port: '8080',
  allowedHosts: [
      '.amazonaws.com'
  ]
},

I did not need to use the --host or --public params.

How to remove trailing and leading whitespace for user-provided input in a batch file?

I'd like to present a compact solution using a call by reference (yes, "batch" has pointers too!) to a function, and a "subfunction":

  @ECHO OFF
  SETLOCAL ENABLEDELAYEDEXPANSION

  SET /p NAME=- NAME ? 
  ECHO "%NAME%"
  CALL :TRIM NAME
  ECHO "%NAME%"
  GOTO :EOF

  :TRIM
  SetLocal EnableDelayedExpansion
  Call :TRIMSUB %%%1%%
  EndLocal & set %1=%tempvar%
  GOTO :EOF

  :TRIMSUB
  set tempvar=%*
  GOTO :EOF

git remote prune – didn't show as many pruned branches as I expected

When you use git push origin :staleStuff, it automatically removes origin/staleStuff, so when you ran git remote prune origin, you have pruned some branch that was removed by someone else. It's more likely that your co-workers now need to run git prune to get rid of branches you have removed.

So what exactly git remote prune does? Main idea: local branches (not tracking branches) are not touched by git remote prune command and should be removed manually.

Now, a real-world example for better understanding:

You have a remote repository with 2 branches: master and feature. Let's assume that you are working on both branches, so as a result you have these references in your local repository (full reference names are given to avoid any confusion):

refs/heads/master (short name master)
refs/heads/feature (short name feature)
refs/remotes/origin/master (short name origin/master)
refs/remotes/origin/feature (short name origin/feature)

Now, a typical scenario:

Some other developer finishes all work on the feature, merges it into master and removes feature branch from remote repository.
By default, when you do git fetch (or git pull), no references are removed from your local repository, so you still have all those 4 references.
You decide to clean them up, and run git remote prune origin.
git detects that feature branch no longer exists, so refs/remotes/origin/feature is a stale branch which should be removed.
Now you have 3 references, including refs/heads/feature, because git remote prune does not remove any refs/heads/* references.

It is possible to identify local branches, associated with remote tracking branches, by branch.<branch_name>.merge configuration parameter. This parameter is not really required for anything to work (probably except git pull), so it might be missing.

(updated with example & useful info from comments)

How do you write to a folder on an SD card in Android?

Found the answer here - http://mytechead.wordpress.com/2014/01/30/android-create-a-file-and-write-to-external-storage/

It says,

/**

* Method to check if user has permissions to write on external storage or not

*/

public static boolean canWriteOnExternalStorage() {
   // get the state of your external storage
   String state = Environment.getExternalStorageState();
   if (Environment.MEDIA_MOUNTED.equals(state)) {
    // if storage is mounted return true
      Log.v("sTag", "Yes, can write to external storage.");
      return true;
   }
   return false;
}

and then let’s use this code to actually write to the external storage:

// get the path to sdcard
File sdcard = Environment.getExternalStorageDirectory();
// to this path add a new directory path
File dir = new File(sdcard.getAbsolutePath() + "/your-dir-name/");
// create this directory if not already created
dir.mkdir();
// create the file in which we will write the contents
File file = new File(dir, "My-File-Name.txt");
FileOutputStream os = outStream = new FileOutputStream(file);
String data = "This is the content of my file";
os.write(data.getBytes());
os.close();

And this is it. If now you visit your /sdcard/your-dir-name/ folder you will see a file named - My-File-Name.txt with the content as specified in the code.

PS:- You need the following permission -

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

How to load a UIView using a nib file created with Interface Builder

I found this blog posting by Aaron Hillegass (author, instructor, Cocoa ninja) to be very enlightening. Even if you don't adopt his modified approach to loading NIB files through a designated initializer you will probably at least get a better understanding of the process that's going on. I've been using this method lately to great success!

Heroku "psql: FATAL: remaining connection slots are reserved for non-replication superuser connections"

This exception happened when I forgot to close the connections

Pass multiple optional parameters to a C# function

C# 4.0 also supports optional parameters, which could be useful in some other situations. See this article.

Rails find_or_create_by more than one attribute?

In Rails 4 you could do:

GroupMember.find_or_create_by(member_id: 4, group_id: 7)

And use where is different:

GroupMember.where(member_id: 4, group_id: 7).first_or_create

This will call create on GroupMember.where(member_id: 4, group_id: 7):

GroupMember.where(member_id: 4, group_id: 7).create

On the contrary, the find_or_create_by(member_id: 4, group_id: 7) will call create on GroupMember:

GroupMember.create(member_id: 4, group_id: 7)

Please see this relevant commit on rails/rails.

What is the difference between JOIN and JOIN FETCH when using JPA and Hibernate

Dherik : I'm not sure about what you say, when you don't use fetch the result will be of type : List<Object[ ]> which means a list of Object tables and not a list of Employee.

Object[0] refers an Employee entity 
Object[1] refers a Departement entity

When you use fetch, there is just one select and the result is the list of Employee List<Employee> containing the list of departements. It overrides the lazy declaration of the entity.

Passing HTML to template using Flask/Jinja2

You can also declare it HTML safe from the code:

from flask import Markup
value = Markup('<strong>The HTML String</strong>')

Then pass that value to the templates and they don't have to |safe it.

Cloning an array in Javascript/Typescript

Try this:

[https://lodash.com/docs/4.17.4#clone][1]

var objects = [{ 'a': 1 }, { 'b': 2 }];

var shallow = _.clone(objects);
console.log(shallow[0] === objects[0]);
// => true

Package opencv was not found in the pkg-config search path

it seems that the ubuntu community has completed the documentation on installing openCV,

so all you have to do now is to download the installation script from here and execute it.

don't forget to make it executable:

chmod +x opencv_latest.sh

then

./opencv_latest.sh

How to get a date in YYYY-MM-DD format from a TSQL datetime field?

replace(convert(varchar, getdate(), 111), '/','-')

Will also do trick without "chopping anything off".

How to make a .jar out from an Android Studio project

Open build.gradle for library project
Write two tasks in build.gradle -- deleteJar and createJar and add rule createJar.dependsOn(deleteJar, build)

The code from above:

task deleteJar(type: Delete) {
    delete 'libs/jars/logmanagementlib.jar'
}           

task createJar(type: Copy) {
    from('build/intermediates/bundles/release/')
    into('libs/jars/')
    include('classes.jar')
    rename('classes.jar', 'logmanagementlib.jar')
}

createJar.dependsOn(deleteJar, build)

Expand gradle panel from right and open all tasks under yourlibrary->others. You will see two new tasks there -- createJar and deleteJar
Double click on createJar
Once the task run successfully, get your generated jar from path mentioned in createJar task i.e. libs/xxxx.jar
copy the newly generated jar into your required project's lib folder-->right click-->select "add as library"

How to create Haar Cascade (.xml file) to use in OpenCV?

This might be helpful

http://opencvuser.blogspot.in/2011/08/creating-haar-cascade-classifier-aka.html

How to check a channel is closed or not without reading it?

There's no way to write a safe application where you need to know whether a channel is open without interacting with it.

The best way to do what you're wanting to do is with two channels -- one for the work and one to indicate a desire to change state (as well as the completion of that state change if that's important).

Channels are cheap. Complex design overloading semantics isn't.

[also]

<-time.After(1e9)

is a really confusing and non-obvious way to write

time.Sleep(time.Second)

Keep things simple and everyone (including you) can understand them.

Eclipse: The declared package does not match the expected package

I get this problem in Eclipse sometimes when importing an Android project that does not have a .classpath file. The one that Eclipse creates is not exactly the same one that Android expects. But, the Android .classpath files are usually all relative, so I just copy a correct .classpath file from another project over the incorrect .classpath. I've created a video that shows how I do this: https://www.youtube.com/watch?v=IVIhgeahS1Ynto

Is it possible to send a variable number of arguments to a JavaScript function?

The apply function takes two arguments; the object this will be binded to, and the arguments, represented with an array.

some_func = function (a, b) { return b }
some_func.apply(obj, ["arguments", "are", "here"])
// "are"

Clear form after submission with jQuery

try this in your post methods callback function

$(':input','#myform')
 .not(':button, :submit, :reset, :hidden')
 .val('')
 .removeAttr('checked')
 .removeAttr('selected');

for more info read this

Twitter Bootstrap vs jQuery UI?

I have on several projects.

The biggest difference in my opinion

jQuery UI is fallback safe, it works correctly and looks good in old browsers, where Bootstrap is based on CSS3 which basically means GREAT in new browsers, not so great in old
Update frequency: Bootstrap is getting some great big updates with awesome new features, but sadly they might break previous code, so you can't just install bootstrap and update when there is a new major release, it basically requires a lot of new coding
jQuery UI is based on good html structure with transformations from JavaScript, while Bootstrap is based on visually and customizable inline structure. (calling a widget in JQUERY UI, defining it in Bootstrap)

So what to choose?

That always depends on the type of project you are working on. Is cool and fast looking widgets better, or are your users often using old browsers?

I always end up using both, so I can use the best of both worlds.

Here are the links to both frameworks, if you decide to use them.

Factory Pattern. When to use factory methods?

I like thinking about design pattens in terms of my classes being 'people,' and the patterns are the ways that the people talk to each other.

So, to me the factory pattern is like a hiring agency. You've got someone that will need a variable number of workers. This person may know some info they need in the people they hire, but that's it.

So, when they need a new employee, they call the hiring agency and tell them what they need. Now, to actually hire someone, you need to know a lot of stuff - benefits, eligibility verification, etc. But the person hiring doesn't need to know any of this - the hiring agency handles all of that.

In the same way, using a Factory allows the consumer to create new objects without having to know the details of how they're created, or what their dependencies are - they only have to give the information they actually want.

public interface IThingFactory
{
    Thing GetThing(string theString);
}

public class ThingFactory : IThingFactory
{
    public Thing GetThing(string theString)
    {
        return new Thing(theString, firstDependency, secondDependency);
    }
}

So, now the consumer of the ThingFactory can get a Thing, without having to know about the dependencies of the Thing, except for the string data that comes from the consumer.

What is the regex for "Any positive integer, excluding 0"

Try this one, this one works best to suffice the requiremnt.

[1-9][0-9]*

Here is the sample output

String 0 matches regex: false
String 1 matches regex: true
String 2 matches regex: true
String 3 matches regex: true
String 4 matches regex: true
String 5 matches regex: true
String 6 matches regex: true
String 7 matches regex: true
String 8 matches regex: true
String 9 matches regex: true
String 10 matches regex: true
String 11 matches regex: true
String 12 matches regex: true
String 13 matches regex: true
String 14 matches regex: true
String 15 matches regex: true
String 16 matches regex: true
String 999 matches regex: true
String 2654 matches regex: true
String 25633 matches regex: true
String 254444 matches regex: true
String 0.1 matches regex: false
String 0.2 matches regex: false
String 0.3 matches regex: false
String -1 matches regex: false
String -2 matches regex: false
String -5 matches regex: false
String -6 matches regex: false
String -6.8 matches regex: false
String -9 matches regex: false
String -54 matches regex: false
String -29 matches regex: false
String 1000 matches regex: true
String 100000 matches regex: true

Output a NULL cell value in Excel

As you've indicated, you can't output NULL in an excel formula. I think this has to do with the fact that the formula itself causes the cell to not be able to be NULL. "" is the next best thing, but sometimes it's useful to use 0.

--EDIT--

Based on your comment, you might want to check out this link. http://peltiertech.com/WordPress/mind-the-gap-charting-empty-cells/

It goes in depth on the graphing issues and what the various values represent, and how to manipulate their output on a chart.

I'm not familiar with VSTO I'm afraid. So I won't be much help there. But if you are really placing formulas in the cell, then there really is no way. ISBLANK() only tests to see if a cell is blank or not, it doesn't have a way to make it blank. It's possible to write code in VBA (and VSTO I imagine) that would run on a worksheet_change event and update the various values instead of using formulas. But that would be cumbersome and performance would take a hit.

What's the function like sum() but for multiplication? product()?

Update:

In Python 3.8, the prod function was added to the math module. See: math.prod().

Older info: Python 3.7 and prior

The function you're looking for would be called prod() or product() but Python doesn't have that function. So, you need to write your own (which is easy).

Pronouncement on prod()

Yes, that's right. Guido rejected the idea for a built-in prod() function because he thought it was rarely needed.

Alternative with reduce()

As you suggested, it is not hard to make your own using reduce() and operator.mul():

from functools import reduce  # Required in Python 3
import operator
def prod(iterable):
    return reduce(operator.mul, iterable, 1)

>>> prod(range(1, 5))
24

Note, in Python 3, the reduce() function was moved to the functools module.

Specific case: Factorials

As a side note, the primary motivating use case for prod() is to compute factorials. We already have support for that in the math module:

>>> import math

>>> math.factorial(10)
3628800

Alternative with logarithms

If your data consists of floats, you can compute a product using sum() with exponents and logarithms:

>>> from math import log, exp

>>> data = [1.2, 1.5, 2.5, 0.9, 14.2, 3.8]
>>> exp(sum(map(log, data)))
218.53799999999993

>>> 1.2 * 1.5 * 2.5 * 0.9 * 14.2 * 3.8
218.53799999999998

Note, the use of log() requires that all the inputs are positive.

GIT fatal: ambiguous argument 'HEAD': unknown revision or path not in the working tree

As others pointed out, this message is coming from your shell prompt. The problem is that in a freshly created repository HEAD (.git/HEAD) points to a ref that doesn't exist yet.

% git init test
Initialized empty shared Git repository in /Users/jhelwig/tmp/test/.git/
% cd test
% cat .git/HEAD
ref: refs/heads/master
% ls -l .git/refs/heads
total 0
% git rev-parse HEAD
HEAD
fatal: ambiguous argument 'HEAD': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions

It looks like rev-parse is being used without sufficient error checking before-hand. After the first commit has been created .git/refs/heads looks a bit different and git rev-parse HEAD will no longer fail.

% ls -l .git/refs/heads
total 4
-rw------- 1 jhelwig staff 41 Oct 14 16:07 master
% git rev-parse HEAD
af0f70f8962f8b88eef679a1854991cb0f337f89

In the function that updates the Git information for the rest of my shell prompt (heavily modified version of wunjo prompt theme for ZSH), I have the following to get around this:

zgit_info_update() {
    zgit_info=()

    local gitdir=$(git rev-parse --git-dir 2>/dev/null)
    if [ $? -ne 0 ] || [ -z "$gitdir" ]; then
        return
    fi

    # More code ...
}

java.lang.OutOfMemoryError: bitmap size exceeds VM budget - Android

I had the same problem just with switching the background images with reasonable sizes. I got better results with setting the ImageView to null before putting in a new picture.

ImageView ivBg = (ImageView) findViewById(R.id.main_backgroundImage);
ivBg.setImageDrawable(null);
ivBg.setImageDrawable(getResources().getDrawable(R.drawable.new_picture));

Angular 2 Sibling Component Communication

Behaviour subjects. I wrote a blog about that.

import { BehaviorSubject } from 'rxjs/BehaviorSubject';
private noId = new BehaviorSubject<number>(0); 
  defaultId = this.noId.asObservable();

newId(urlId) {
 this.noId.next(urlId); 
 }

In this example i am declaring a noid behavior subject of type number. Also it is an observable. And if "something happend" this will change with the new(){} function.

So, in the sibling's components, one will call the function, to make the change, and the other one will be affected by that change, or vice-versa.

For example, I get the id from the URL and update the noid from the behavior subject.

public getId () {
  const id = +this.route.snapshot.paramMap.get('id'); 
  return id; 
}

ngOnInit(): void { 
 const id = +this.getId ();
 this.taskService.newId(id) 
}

And from the other side, I can ask if that ID is "what ever i want" and make a choice after that, in my case if i want to delte a task, and that task is the current url, it have to redirect me to the home:

delete(task: Task): void { 
  //we save the id , cuz after the delete function, we  gonna lose it 
  const oldId = task.id; 
  this.taskService.deleteTask(task) 
      .subscribe(task => { //we call the defaultId function from task.service.
        this.taskService.defaultId //here we are subscribed to the urlId, which give us the id from the view task 
                 .subscribe(urlId => {
            this.urlId = urlId ;
                  if (oldId == urlId ) { 
                // Location.call('/home'); 
                this.router.navigate(['/home']); 
              } 
          }) 
    }) 
}

How can I style even and odd elements?

Use this:

li { color:blue; }
li:nth-child(odd) { color:green; }
li:nth-child(even) { color:red; }

See here for info on browser support: http://kimblim.dk/css-tests/selectors/

Get Path from another app (WhatsApp)

Using the code example below will return to you the bitmap :

BitmapFactory.decodeStream(getContentResolver().openInputStream(Uri.parse("content://com.whatsapp.provider.media/item/128752")))

After that you all know what you have to do.

How create a new deep copy (clone) of a List<T>?

C# 9 records and with expressions can make it a little easier, especially if your type has many properties.

You can use something like:

var books2 = books1.Select(b => b with { }).ToList();

I did this as an example:

record Book
{
    public string Name { get; set; }
}

static void Main()
{
    List<Book> books1 = new List<Book>()
    {
        new Book { Name = "Book1.1" },
        new Book { Name = "Book1.2" },
        new Book { Name = "Book1.3" }
    };

    var books2 = books1.Select(b => b with { }).ToList();

    books2[0].Name = "Changed";
    books2[1].Name = "Changed";

    Console.WriteLine("Book1");
    foreach (var item in books1)
    {
        Console.WriteLine(item);
    }

    Console.WriteLine("Book2");
    foreach (var item in books2)
    {
        Console.WriteLine(item);
    }
}

And the result was:

Book1

Book { Name = Book1.1 }

Book { Name = Book1.2 }

Book { Name = Book1.3 }

Book2

Book { Name = Changed }

Book { Name = Changed }

Book { Name = Book1.3 }

jQuery - Redirect with post data

why not just use a button instead of submit. clicking the button will let you construct a proper url for your browser to redirect to.

$("#button").click(function() {
   var url = 'site.com/process.php?';
   $('form input').each(function() {
       url += 'key=' + $(this).val() + "&";
   });
   // handle removal of last &.

   window.location.replace(url);
});

how to use javascript Object.defineProperty

defineProperty is a method on Object which allow you to configure the properties to meet some criterias. Here is a simple example with an employee object with two properties firstName & lastName and append the two properties by overriding the toString method on the object.

var employee = {
    firstName: "Jameel",
    lastName: "Moideen"
};
employee.toString=function () {
    return this.firstName + " " + this.lastName;
};
console.log(employee.toString());

You will get Output as : Jameel Moideen

I am going to change the same code by using defineProperty on the object

var employee = {
    firstName: "Jameel",
    lastName: "Moideen"
};
Object.defineProperty(employee, 'toString', {
    value: function () {
        return this.firstName + " " + this.lastName;
    },
    writable: true,
    enumerable: true,
    configurable: true
});
console.log(employee.toString());

The first parameter is the name of the object and then second parameter is name of the property we are adding , in our case it’s toString and then the last parameter is json object which have a value going to be a function and three parameters writable,enumerable and configurable.Right now I just declared everything as true.

If u run the example you will get Output as : Jameel Moideen

Let’s understand why we need the three properties such as writable,enumerable and configurable.

writable

One of the very annoying part of the javascript is , if you change the toString property to something else for example

if you run this again , everything gets breaks. Let’s change writable to false. If run the same again you will get the correct output as ‘Jameel Moideen’ . This property will prevent overwrite this property later.

enumerable

if you print all the keys inside the object , you can see all the properties including toString.

console.log(Object.keys(employee));

if you set enumerable to false , you can hide toString property from everybody else. If run this again you will get firstName,lastName

configurable

if someone later redefined the object on later for example enumerable to true and run it. You can see toString property came again.

var employee = {
    firstName: "Jameel",
    lastName: "Moideen"
};
Object.defineProperty(employee, 'toString', {
    value: function () {
        return this.firstName + " " + this.lastName;
    },
    writable: false,
    enumerable: false,
    configurable: true
});

//change enumerable to false
Object.defineProperty(employee, 'toString', {

    enumerable: true
});
employee.toString="changed";
console.log(Object.keys(employee));

you can restrict this behavior by set configurable to false.

Orginal reference of this information is from my personal Blog

make script execution to unlimited

Your script could be stopping, not because of the PHP timeout but because of the timeout in the browser you're using to access the script (ie. Firefox, Chrome, etc). Unfortunately there's seldom an easy way to extend this timeout, and in most browsers you simply can't. An option you have here is to access the script over a terminal. For example, on Windows you would make sure the PHP executable is in your path variable and then I think you execute:

C:\path\to\script> php script.php

Or, if you're using the PHP CGI, I think it's:

C:\path\to\script> php-cgi script.php

Plus, you would also set ini_set('max_execution_time', 0); in your script as others have mentioned. When running a PHP script this way, I'm pretty sure you can use buffer flushing to echo out the script's progress to the terminal periodically if you wish. The biggest issue I think with this method is there's really no way of stopping the script once it's started, other than stopping the entire PHP process or service.

How to get numbers after decimal point?

Float numbers are not stored in decimal (base10) format. Have a read through the python documentation on this to satisfy yourself why. Therefore, to get a base10 representation from a float is not advisable.

Now there are tools which allow storage of numeric data in decimal format. Below is an example using the Decimal library.

from decimal import *

x = Decimal('0.341343214124443151466')
str(x)[-2:] == '66'  # True

y = 0.341343214124443151466
str(y)[-2:] == '66'  # False

How can I set the color of a selected row in DataGrid

The default IsSelected trigger changes 3 properties, Background, Foreground & BorderBrush. If you want to change the border as well as the background, just include this in your style trigger.

<Style TargetType="{x:Type dg:DataGridCell}">
    <Style.Triggers>
        <Trigger Property="dg:DataGridCell.IsSelected" Value="True">
            <Setter Property="Background" Value="#CCDAFF" />
            <Setter Property="BorderBrush" Value="Black" />
        </Trigger>
    </Style.Triggers>
</Style>

How to build x86 and/or x64 on Windows from command line with CMAKE?

This cannot be done with CMake. You have to generate two separate build folders. One for the x86 NMake build and one for the x64 NMake build. You cannot generate a single Visual Studio project covering both architectures with CMake, either.

To build Visual Studio projects from the command line for both 32-bit and 64-bit without starting a Visual Studio command prompt, use the regular Visual Studio generators.

For CMake 3.13 or newer, run the following commands:

cmake -G "Visual Studio 16 2019" -A Win32 -S \path_to_source\ -B "build32"
cmake -G "Visual Studio 16 2019" -A x64 -S \path_to_source\ -B "build64"
cmake --build build32 --config Release
cmake --build build64 --config Release

For earlier versions of CMake, run the following commands:

mkdir build32 & pushd build32
cmake -G "Visual Studio 15 2017" \path_to_source\
popd
mkdir build64 & pushd build64
cmake -G "Visual Studio 15 2017 Win64" \path_to_source\
popd
cmake --build build32 --config Release
cmake --build build64 --config Release

CMake generated projects that use one of the Visual Studio generators can be built from the command line with using the option --build followed by the build directory. The --config option specifies the build configuration.

Install numpy on python3.3 - Install pip for python3

I'm on Ubuntu 15.04. This seemed to work:

$ sudo pip3 install numpy

On RHEL this worked:

$ sudo python3 -m pip install numpy

WCF Exception: Could not find a base address that matches scheme http for the endpoint

My issue was caused by missing bindings in IIS, in the left tree view "Connections", under Sites, Right click on your site > edit bindings > add > https

Choose 'IIS Express Development Certificate' and set port to 443 Then I added another binding to the webconfig:

<endpoint address="wsHttps" binding="wsHttpBinding" bindingConfiguration="DefaultWsHttpBinding" name="Your.bindingname" contract="Your.contract" />

Also added to serviceBehaviours: <serviceMetadata httpGetEnabled="false" httpsGetEnabled="true" />

And eventually it worked, none of the solutions I checked on stackoverflow for this error was applicable to my specific scenario, so including here in case it helps others

What do Clustered and Non clustered index actually mean?

With a clustered index the rows are stored physically on the disk in the same order as the index. Therefore, there can be only one clustered index.

With a non clustered index there is a second list that has pointers to the physical rows. You can have many non clustered indices, although each new index will increase the time it takes to write new records.

It is generally faster to read from a clustered index if you want to get back all the columns. You do not have to go first to the index and then to the table.

Writing to a table with a clustered index can be slower, if there is a need to rearrange the data.

De-obfuscate Javascript code to make it readable again

I have tried both of online jsbeautifier(jsbeautifier, jsnice), these tools gave me beautiful js code,

but couldn't copy for very large js (must be bug, when i copy, copied buffer contains only one character '-').

I found that only working solution was prettyjs:

http://www.thaoh.net/prettyjs/

How to use @Nullable and @Nonnull annotations more effectively?

I think this original question indirectly points to a general recommendation that run-time null-pointer check is still needed, even though @NonNull is used. Refer to the following link:

Java 8's new Type Annotations

In the above blog, it is recommended that:

Optional Type Annotations are not a substitute for runtime validation Before Type Annotations, the primary location for describing things like nullability or ranges was in the javadoc. With Type annotations, this communication comes into the bytecode in a way for compile-time verification. Your code should still perform runtime validation.

How do I make a request using HTTP basic authentication with PHP curl?

Unlike SOAP, REST isn't a standardized protocol so it's a bit difficult to have a "REST Client". However, since most RESTful services use HTTP as their underlying protocol, you should be able to use any HTTP library. In addition to cURL, PHP has these via PEAR:

HTTP_Request2

which replaced

HTTP_Request

A sample of how they do HTTP Basic Auth

// This will set credentials for basic auth
$request = new HTTP_Request2('http://user:[email protected]/secret/');

The also support Digest Auth

// This will set credentials for Digest auth
$request->setAuth('user', 'password', HTTP_Request2::AUTH_DIGEST);

NavigationBar bar, tint, and title text color in iOS 8

Swift 4.1

Add a func to viewDidLoad

override func viewDidLoad() {
  super.viewDidLoad()

  setup()
}

In the setup() function add:

func setup() {

        navigationController?.navigationBar.prefersLargeTitles = true
        navigationController?.navigationBar.barStyle = .blackOpaque
        navigationItem.title = "YOUR_TITLE_HERE"
        navigationController?.navigationBar.barTintColor = .black
        let attributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
        navigationController?.navigationBar.largeTitleTextAttributes = attributes
    }

How do you divide each element in a list by an int?

>>> myList = [10,20,30,40,50,60,70,80,90]
>>> myInt = 10
>>> newList = map(lambda x: x/myInt, myList)
>>> newList
[1, 2, 3, 4, 5, 6, 7, 8, 9]

Linq to Entities join vs groupjoin

According to eduLINQ:

The best way to get to grips with what GroupJoin does is to think of Join. There, the overall idea was that we looked through the "outer" input sequence, found all the matching items from the "inner" sequence (based on a key projection on each sequence) and then yielded pairs of matching elements. GroupJoin is similar, except that instead of yielding pairs of elements, it yields a single result for each "outer" item based on that item and the sequence of matching "inner" items.

The only difference is in return statement:

Join:

var lookup = inner.ToLookup(innerKeySelector, comparer); 
foreach (var outerElement in outer) 
{ 
    var key = outerKeySelector(outerElement); 
    foreach (var innerElement in lookup[key]) 
    { 
        yield return resultSelector(outerElement, innerElement); 
    } 
}

GroupJoin:

var lookup = inner.ToLookup(innerKeySelector, comparer); 
foreach (var outerElement in outer) 
{ 
    var key = outerKeySelector(outerElement); 
    yield return resultSelector(outerElement, lookup[key]); 
}

Programs & Examples On #Opensolaris