Programs & Examples On #Scalaquery

ScalaQuery is a typesafe API / DSL (domain specific language) built on top of JDBC for accessing relational databases in Scala.

How can I disable the Maven Javadoc plugin from the command line?

The Javadoc generation can be skipped by setting the property maven.javadoc.skip to true [1], i.e.

-Dmaven.javadoc.skip=true

(and not false)

Replace multiple strings at once

A more visual approach:

String.prototype.htmlProtect = function() {
  var replace_map;

  replace_map = {
    '\n': '<br />',
    '<': '&lt;',
    '>': '&gt;'
  };

  return this.replace(/[<>\n]/g, function(match) { // be sure to add every char in the pattern
    return replace_map[match];
  });
};

and this is how you call it:

var myString = "<b>tell me a story, \n<i>bro'</i>";
var myNewString = myString.htmlProtect();

// &lt;b&gt;tell me a story, <br />&lt;i&gt;bro'&lt;/i&gt;

Height equal to dynamic width (CSS fluid layout)

Using jQuery you can achieve this by doing

var cw = $('.child').width();
$('.child').css({'height':cw+'px'});

Check working example at http://jsfiddle.net/n6DAu/1/

How do you initialise a dynamic array in C++?

C++ has no specific feature to do that. However, if you use a std::vector instead of an array (as you probably should do) then you can specify a value to initialise the vector with.

std::vector <char> v( 100, 42 );

creates a vector of size 100 with all values initialised to 42.

How to get the error message from the error code returned by GetLastError()?

If you're using c# you can use this code:

using System.Runtime.InteropServices;

public static class WinErrors
{
    #region definitions
    [DllImport("kernel32.dll", SetLastError = true)]
    static extern IntPtr LocalFree(IntPtr hMem);

    [DllImport("kernel32.dll", SetLastError = true)]
    static extern int FormatMessage(FormatMessageFlags dwFlags, IntPtr lpSource, uint dwMessageId, uint dwLanguageId, ref IntPtr lpBuffer, uint nSize, IntPtr Arguments);

    [Flags]
    private enum FormatMessageFlags : uint
    {
        FORMAT_MESSAGE_ALLOCATE_BUFFER = 0x00000100,
        FORMAT_MESSAGE_IGNORE_INSERTS = 0x00000200,
        FORMAT_MESSAGE_FROM_SYSTEM = 0x00001000,
        FORMAT_MESSAGE_ARGUMENT_ARRAY = 0x00002000,
        FORMAT_MESSAGE_FROM_HMODULE = 0x00000800,
        FORMAT_MESSAGE_FROM_STRING = 0x00000400,
    }
    #endregion

    /// <summary>
    /// Gets a user friendly string message for a system error code
    /// </summary>
    /// <param name="errorCode">System error code</param>
    /// <returns>Error string</returns>
    public static string GetSystemMessage(int errorCode)
    {
        try
        {
            IntPtr lpMsgBuf = IntPtr.Zero;

            int dwChars = FormatMessage(
                FormatMessageFlags.FORMAT_MESSAGE_ALLOCATE_BUFFER | FormatMessageFlags.FORMAT_MESSAGE_FROM_SYSTEM | FormatMessageFlags.FORMAT_MESSAGE_IGNORE_INSERTS,
                IntPtr.Zero,
                (uint) errorCode,
                0, // Default language
                ref lpMsgBuf,
                0,
                IntPtr.Zero);
            if (dwChars == 0)
            {
                // Handle the error.
                int le = Marshal.GetLastWin32Error();
                return "Unable to get error code string from System - Error " + le.ToString();
            }

            string sRet = Marshal.PtrToStringAnsi(lpMsgBuf);

            // Free the buffer.
            lpMsgBuf = LocalFree(lpMsgBuf);
            return sRet;
        }
        catch (Exception e)
        {
            return "Unable to get error code string from System -> " + e.ToString();
        }
    }
}

Android findViewById() in Custom View

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
    ImageHolder holder = null;
    if (row == null) {
        LayoutInflater inflater = ((Activity) context).getLayoutInflater();
        row = inflater.inflate(layoutResourceId, parent, false);
        holder = new ImageHolder();
        editText = (EditText) row.findViewById(R.id.id_number_custom);
        loadButton = (ImageButton) row.findViewById(R.id.load_data_button);
        row.setTag(holder);
    } else {
        holder = (ImageHolder) row.getTag();
    }


    holder.editText.setText("Your Value");
    holder.loadButton.setImageBitmap("Your Bitmap Value");
    return row;
}

How to generate Class Diagram (UML) on Android Studio (IntelliJ Idea)

For those who want to use simpleUML in Android Studio and having issues in running SimpleUML.

First download simpleUML jar from here https://plugins.jetbrains.com/plugin/4946-simpleumlce

Now follow the below steps.

Step 1:

Click on File and go to Settings (File ? Settings)

Step 2

Select Plugins from Left Panel and click Install plugin from disk


1]

Step 3:

Locate the SimpleUML jar file and select it.

2]

Step 4:

Now Restart Android Studio (File ? Invalidate Caches/Restart ? Just Restart)

Step 5:

After you restart Right Click the Package name and Select New Diagram or Add to simpleUML Diagram ? New Diagram.

3

Step 6:

Set a file name and create UML file. I created with name NewDiagram

enter image description here Step 7:

Now Right Click the Package name and Select the file you created. In my case it was NewDiagram

enter image description here

Step 8:

All files are stacked on top of one another. You can just drag and drop them and set a hierarchy.

enter image description here

Like this below, you can drag these classes

enter image description here

What is std::move(), and when should it be used?

Q: What is std::move?

A: std::move() is a function from the C++ Standard Library for casting to a rvalue reference.

Simplisticly std::move(t) is equivalent to:

static_cast<T&&>(t);

An rvalue is a temporary that does not persist beyond the expression that defines it, such as an intermediate function result which is never stored in a variable.

int a = 3; // 3 is a rvalue, does not exist after expression is evaluated
int b = a; // a is a lvalue, keeps existing after expression is evaluated

An implementation for std::move() is given in N2027: "A Brief Introduction to Rvalue References" as follows:

template <class T>
typename remove_reference<T>::type&&
std::move(T&& a)
{
    return a;
}

As you can see, std::move returns T&& no matter if called with a value (T), reference type (T&), or rvalue reference (T&&).

Q: What does it do?

A: As a cast, it does not do anything during runtime. It is only relevant at compile time to tell the compiler that you would like to continue considering the reference as an rvalue.

foo(3 * 5); // obviously, you are calling foo with a temporary (rvalue)

int a = 3 * 5;
foo(a);     // how to tell the compiler to treat `a` as an rvalue?
foo(std::move(a)); // will call `foo(int&& a)` rather than `foo(int a)` or `foo(int& a)`

What it does not do:

  • Make a copy of the argument
  • Call the copy constructor
  • Change the argument object

Q: When should it be used?

A: You should use std::move if you want to call functions that support move semantics with an argument which is not an rvalue (temporary expression).

This begs the following follow-up questions for me:

  • What is move semantics? Move semantics in contrast to copy semantics is a programming technique in which the members of an object are initialized by 'taking over' instead of copying another object's members. Such 'take over' makes only sense with pointers and resource handles, which can be cheaply transferred by copying the pointer or integer handle rather than the underlying data.

  • What kind of classes and objects support move semantics? It is up to you as a developer to implement move semantics in your own classes if these would benefit from transferring their members instead of copying them. Once you implement move semantics, you will directly benefit from work from many library programmers who have added support for handling classes with move semantics efficiently.

  • Why can't the compiler figure it out on its own? The compiler cannot just call another overload of a function unless you say so. You must help the compiler choose whether the regular or move version of the function should be called.

  • In which situations would I want to tell the compiler that it should treat a variable as an rvalue? This will most likely happen in template or library functions, where you know that an intermediate result could be salvaged.

How to copy JavaScript object to new variable NOT by reference?

Your only option is to somehow clone the object.

See this stackoverflow question on how you can achieve this.

For simple JSON objects, the simplest way would be:

var newObject = JSON.parse(JSON.stringify(oldObject));

if you use jQuery, you can use:

// Shallow copy
var newObject = jQuery.extend({}, oldObject);

// Deep copy
var newObject = jQuery.extend(true, {}, oldObject);

UPDATE 2017: I should mention, since this is a popular answer, that there are now better ways to achieve this using newer versions of javascript:

In ES6 or TypeScript (2.1+):

var shallowCopy = { ...oldObject };

var shallowCopyWithExtraProp = { ...oldObject, extraProp: "abc" };

Note that if extraProp is also a property on oldObject, its value will not be used because the extraProp : "abc" is specified later in the expression, which essentially overrides it. Of course, oldObject will not be modified.

Java: Local variable mi defined in an enclosing scope must be final or effectively final

What you have here is a non-local variable (https://en.wikipedia.org/wiki/Non-local_variable), i.e. you access a local variable in a method an anonymous class.

Local variables of the method are kept on the stack and lost as soon as the method ends, however even after the method ends, the local inner class object is still alive on the heap and will need to access this variable (here, when an action is performed).

I would suggest two workarounds : Either you make your own class that implements actionlistenner and takes as constructor argument, your variable and keeps it as an class attribute. Therefore you would only access this variable within the same object.

Or (and this is probably the best solution) just qualify a copy of the variable final to access it in the inner scope as the error suggests to make it a constant:

This would suit your case since you are not modifying the value of the variable.

Getting IP address of client

I use the following static helper method to retrieve the IP of a client:

public static String getClientIpAddr(HttpServletRequest request) {  
    String ip = request.getHeader("X-Forwarded-For");  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("Proxy-Client-IP");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("WL-Proxy-Client-IP");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("HTTP_X_FORWARDED_FOR");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("HTTP_X_FORWARDED");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("HTTP_X_CLUSTER_CLIENT_IP");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("HTTP_CLIENT_IP");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("HTTP_FORWARDED_FOR");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("HTTP_FORWARDED");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("HTTP_VIA");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getHeader("REMOTE_ADDR");  
    }  
    if (ip == null || ip.length() == 0 || ip.equalsIgnoreCase("unknown")) {  
        ip = request.getRemoteAddr();  
    }  
    return ip;  
}

Something like 'contains any' for Java set?

Wouldn't Collections.disjoint(A, B) work? From the documentation:

Returns true if the two specified collections have no elements in common.

Thus, the method returns false if the collections contains any common elements.

How to represent the double quotes character (") in regex?

you need to use backslash before ". like \"

From the doc here you can see that

A character preceded by a backslash ( \ ) is an escape sequence and has special meaning to the compiler.

and " (double quote) is a escacpe sequence

When an escape sequence is encountered in a print statement, the compiler interprets it accordingly. For example, if you want to put quotes within quotes you must use the escape sequence, \", on the interior quotes. To print the sentence

She said "Hello!" to me.

you would write

System.out.println("She said \"Hello!\" to me.");

How to pass parameter to click event in Jquery

Better Approach:

<script type="text/javascript">
    $('#btn').click(function() {
      var id = $(this).attr('id');
      alert(id);
    });
</script>

<input id="btn" type="button" value="click" />

But, if you REALLY need to do the click handler inline, this will work:

<script type="text/javascript">
    function display(el) {
        var id = $(el).attr('id');
        alert(id);
    }
</script>

<input id="btn" type="button" value="click" OnClick="display(this);" />

'NOT NULL constraint failed' after adding to models.py

if the zipcode field is not a required field then add null=True and blank=True, then run makemigrations and migrate command to successfully reflect the changes in the database.

MVC4 HTTP Error 403.14 - Forbidden

If you're running IIS 8.5 on Windows 8, or Server 2012, you might find that running mvc 4/5 (.net 4.5) doesn't work in a virtual directory. If you create a local host entry in the host file to point back to your local machine and then point a new local IIS website to that folder (with the matching host header entry) you'll find it works then.

How do I change an HTML selected option using JavaScript?

You could also change select.options.selectedIndex DOM attribute like this:

_x000D_
_x000D_
function selectOption(index){ _x000D_
  document.getElementById("select_id").options.selectedIndex = index;_x000D_
}
_x000D_
<p>_x000D_
<select id="select_id">_x000D_
  <option selected>first option</option>_x000D_
  <option>second option</option>_x000D_
  <option>third option</option>_x000D_
</select>_x000D_
</p>_x000D_
<p>_x000D_
  <button onclick="selectOption(0);">Select first option</button>_x000D_
  <button onclick="selectOption(1);">Select second option</button>_x000D_
  <button onclick="selectOption(2);">Select third option</button>_x000D_
</p>
_x000D_
_x000D_
_x000D_

Java - ignore exception and continue

LDAPService should contain method like LDAPService.isExists(String userName) use it to prevent NPE to be thrown. If is not - this could be a workaround, but use Logging to post some warning..

What is the maximum possible length of a .NET string?

String allocates dynamic memory size in the heap of your RAM. But string address is stored in stack that occupies 4 bytes of memory.

Simple http post example in Objective-C?

 NSMutableDictionary *contentDictionary = [[NSMutableDictionary alloc]init];
[contentDictionary setValue:@"name" forKey:@"email"];
[contentDictionary setValue:@"name" forKey:@"username"];
[contentDictionary setValue:@"name" forKey:@"password"];
[contentDictionary setValue:@"name" forKey:@"firstName"];
[contentDictionary setValue:@"name" forKey:@"lastName"];

NSData *data = [NSJSONSerialization dataWithJSONObject:contentDictionary options:NSJSONWritingPrettyPrinted error:nil];
NSString *jsonStr = [[NSString alloc] initWithData:data
                                          encoding:NSUTF8StringEncoding];
NSLog(@"%@",jsonStr);

NSString *urlString = [NSString stringWithFormat:@"http://testgcride.com:8081/v1/users"];
NSURL *url = [NSURL URLWithString:urlString];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"POST"];
   [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];


[request setHTTPBody:[jsonStr dataUsingEncoding:NSUTF8StringEncoding]];

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
[manager.requestSerializer setAuthorizationHeaderFieldWithUsername:@"moinsam" password:@"cheese"];
manager.requestSerializer = [AFJSONRequestSerializer serializer];

AFHTTPRequestOperation *operation = [manager HTTPRequestOperationWithRequest:request success:<block> failure:<block>];

Yes/No message box using QMessageBox

Python equivalent code for a QMessageBox which consist of a question in it and Yes and No button. When Yes Button is clicked it will pop up another message box saying yes is clicked and same for No button also. You can push your own code after if block.

button_reply = QMessageBox.question(self,"Test", "Are you sure want to quit??", QMessageBox.Yes,QMessageBox.No,)

if button_reply == QMessageBox.Yes:
    QMessageBox.information(self, "Test", "Yes Button Was Clicked")
else :
    QMessageBox.information(self, "Test", "No Button Was Clicked")

Getting Excel to refresh data on sheet from within VBA

After a data connection update, some UDF's were not executing. Using a subroutine, I was trying to recalcuate a single column with:

Sheets("mysheet").Columns("D").Calculate

But above statement had no effect. None of above solutions helped, except kambeeks suggestion to replace formulas worked and was fast if manual recalc turned on during update. Below code solved my problem, even if not exactly responsible to OP "kluge" comment, it provided a fast/reliable solution to force recalculation of user-specified cells.

Application.Calculation = xlManual
DoEvents
For Each mycell In Sheets("mysheet").Range("D9:D750").Cells
    mycell.Formula = mycell.Formula
Next
DoEvents
Application.Calculation = xlAutomatic

How to return temporary table from stored procedure

Take a look at this code,

CREATE PROCEDURE Test

AS
    DECLARE @tab table (no int, name varchar(30))

    insert @tab  select eno,ename from emp  

    select * from @tab
RETURN

How to hide the title bar for an Activity in XML with existing custom theme

I'm using a support widget Toolbar v7. So, in order to be able to delete or hide the Title we need to write this.

Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);

//Remove¡ing title bar
getSupportActionBar().setDisplayShowTitleEnabled(false);

How to run a subprocess with Python, wait for it to exit and get the full stdout as a string?

I'd try something like:

#!/usr/bin/python
from __future__ import print_function

import shlex
from subprocess import Popen, PIPE

def shlep(cmd):
    '''shlex split and popen
    '''
    parsed_cmd = shlex.split(cmd)
    ## if parsed_cmd[0] not in approved_commands:
    ##    raise ValueError, "Bad User!  No output for you!"
    proc = Popen(parsed_command, stdout=PIPE, stderr=PIPE)
    out, err = proc.communicate()
    return (proc.returncode, out, err)

... In other words let shlex.split() do most of the work. I would NOT attempt to parse the shell's command line, find pipe operators and set up your own pipeline. If you're going to do that then you'll basically have to write a complete shell syntax parser and you'll end up doing an awful lot of plumbing.

Of course this raises the question, why not just use Popen with the shell=True (keyword) option? This will let you pass a string (no splitting nor parsing) to the shell and still gather up the results to handle as you wish. My example here won't process any pipelines, backticks, file descriptor redirection, etc that might be in the command, they'll all appear as literal arguments to the command. Thus it is still safer then running with shell=True ... I've given a silly example of checking the command against some sort of "approved command" dictionary or set --- through it would make more sense to normalize that into an absolute path unless you intend to require that the arguments be normalized prior to passing the command string to this function.

ERROR: Error 1005: Can't create table (errno: 121)

Something I noticed was that I had "other_database" and "Other_Database" in my databases. That caused this problem as I actually had same reference in other database which caused this mysterious error!

Using git to get just the latest revision

Use git clone with the --depth option set to 1 to create a shallow clone with a history truncated to the latest commit.

For example:

git clone --depth 1 https://github.com/user/repo.git

To also initialize and update any nested submodules, also pass --recurse-submodules and to clone them shallowly, also pass --shallow-submodules.

For example:

git clone --depth 1 --recurse-submodules --shallow-submodules https://github.com/user/repo.git

Replace \n with <br />

To handle many newline delimiters, including character combinations like \r\n, use splitlines (see this related post) use the following:

'<br />'.join(thatLine.splitlines())

Calling stored procedure from another stored procedure SQL Server

You could add an OUTPUT parameter to test2, and set it to the new id straight after the INSERT using:

SELECT @NewIdOutputParam = SCOPE_IDENTITY()

Then in test1, retrieve it like so:

DECLARE @NewId INTEGER
EXECUTE test2 @NewId OUTPUT
-- Now use @NewId as needed

HTML5 best practices; section/header/aside/article elements

The main mistake: You have "divitis" in the whole document.
Why this?

<header>
    <div id="logo"></div>
    <div id="language"></div>
</header>

Instead of:

<header role="banner">
    <!-- Not the best -->
    <h1 id="logo"></h1> <!-- or <figure> and <figcaption>, or <h1> and <p>... -->
    <h2 id="language"></h2>

    <!-- Better, if the IDs have not semantic sense -->
    <h1></h1>
    <h2></h2>
</header>

To stylize this header, use CSS hierarchy: body > section > header > h1, body > section > header > h2

More, ...line 63: why header wraps h2?? If you do not include any more element inside header, just use a single h2.
Keep in mind, your structure is not to stylize document, but construct a document self-explained.

Apply this to the rest of document; Good luck ;)

How can I grep for a string that begins with a dash/hyphen?

grep "^-X" file

It will grep and pick all the lines form the file. ^ in the grep"^" indicates a line starting with

How to insert special characters into a database?

$var = mysql_real_escape_string("data & the base");
$result = mysql_query('SELECT * FROM php_bugs WHERE php_bugs_category like  "%' .$var.'%"');

How to select the last column of dataframe

Somewhat similar to your original attempt, but more Pythonic, is to use Python's standard negative-indexing convention to count backwards from the end:

df[df.columns[-1]]

HTML select dropdown list

Have <option value="">- Please select a name -</option> as the first option and use JavaScript (and backend validation) to ensure the user has selected something other than an empty value.

How to find Oracle Service Name

Connect to the database with the "system" user, and execute the following command:

show parameter service_name 

MaxLength Attribute not generating client-side validation attributes

Try using the [StringLength] attribute:

[Required(ErrorMessage = "Name is required.")]
[StringLength(40, ErrorMessage = "Name cannot be longer than 40 characters.")]
public string Name { get; set; }

That's for validation purposes. If you want to set for example the maxlength attribute on the input you could write a custom data annotations metadata provider as shown in this post and customize the default templates.

Limiting the number of characters per line with CSS

If you use CSS to select a monospace font, the problem of varying character length is easily solved.

window.location (JS) vs header() (PHP) for redirection

A better way to set the location in JS is via:

window.location.href = 'https://stackoverflow.com';

Whether to use PHP or JS to manage the redirection depends on what your code is doing and how. But if you're in a position to use PHP; that is, if you're going to be using PHP to send some JS code back to the browser that simply tells the browser to go somewhere else, then logic suggests that you should cut out the middle man and tell the browser directly via PHP.

Connect to Active Directory via LDAP

DC is your domain. If you want to connect to the domain example.com than your dc's are: DC=example,DC=com

You actually don't need any hostname or ip address of your domain controller (There could be plenty of them).

Just imagine that you're connecting to the domain itself. So for connecting to the domain example.com you can simply write

DirectoryEntry directoryEntry = new DirectoryEntry("LDAP://example.com");

And you're done.

You can also specify a user and a password used to connect:

DirectoryEntry directoryEntry = new DirectoryEntry("LDAP://example.com", "username", "password");

Also be sure to always write LDAP in upper case. I had some trouble and strange exceptions until I read somewhere that I should try to write it in upper case and that solved my problems.

The directoryEntry.Path Property allows you to dive deeper into your domain. So if you want to search a user in a specific OU (Organizational Unit) you can set it there.

DirectoryEntry directoryEntry = new DirectoryEntry("LDAP://example.com");
directoryEntry.Path = "LDAP://OU=Specific Users,OU=All Users,OU=Users,DC=example,DC=com";

This would match the following AD hierarchy:

  • com
    • example
      • Users
        • All Users
          • Specific Users

Simply write the hierarchy from deepest to highest.

Now you can do plenty of things

For example search a user by account name and get the user's surname:

DirectoryEntry directoryEntry = new DirectoryEntry("LDAP://example.com");
DirectorySearcher searcher = new DirectorySearcher(directoryEntry) {
    PageSize = int.MaxValue,
    Filter = "(&(objectCategory=person)(objectClass=user)(sAMAccountName=AnAccountName))"
};

searcher.PropertiesToLoad.Add("sn");

var result = searcher.FindOne();

if (result == null) {
    return; // Or whatever you need to do in this case
}

string surname;

if (result.Properties.Contains("sn")) {
    surname = result.Properties["sn"][0].ToString();
}

Importing two classes with same name. How to handle?

I hit this issue when, for example, mapping one class to another (such as when switching to a new set of classes to represent person data). At that point, you need both classes because that is the whole point of the code--to map one to the other. And you can't rename the classes in either place (again, the job is to map, not to go change what someone else did).

Fully qualified is one way. It appears you can't actually include both import statements, because Java gets worried about which "Person" is meant, for example.

Use of ~ (tilde) in R programming Language

R defines a ~ (tilde) operator for use in formulas. Formulas have all sorts of uses, but perhaps the most common is for regression:

library(datasets)
lm( myFormula, data=iris)

help("~") or help("formula") will teach you more.

@Spacedman has covered the basics. Let's discuss how it works.

First, being an operator, note that it is essentially a shortcut to a function (with two arguments):

> `~`(lhs,rhs)
lhs ~ rhs
> lhs ~ rhs
lhs ~ rhs

That can be helpful to know for use in e.g. apply family commands.

Second, you can manipulate the formula as text:

oldform <- as.character(myFormula) # Get components
myFormula <- as.formula( paste( oldform[2], "Sepal.Length", sep="~" ) )

Third, you can manipulate it as a list:

myFormula[[2]]
myFormula[[3]]

Finally, there are some helpful tricks with formulae (see help("formula") for more):

myFormula <- Species ~ . 

For example, the version above is the same as the original version, since the dot means "all variables not yet used." This looks at the data.frame you use in your eventual model call, sees which variables exist in the data.frame but aren't explicitly mentioned in your formula, and replaces the dot with those missing variables.

Rename Files and Directories (Add Prefix)

Here is a simple script that you can use. I like using the non-standard module File::chdir to handle managing cd operations, so to use this script as-is you will need to install it (sudo cpan File::chdir).

#!/usr/bin/perl

use strict;
use warnings;

use File::Copy;
use File::chdir; # allows cd-ing by use of $CWD, much easier but needs CPAN module

die "Usage: $0 dir prefix" unless (@ARGV >= 2);
my ($dir, $pre) = @ARGV;

opendir(my $dir_handle, $dir) or die "Cannot open directory $dir";
my @files = readdir($dir_handle);
close($dir_handle);

$CWD = $dir; # cd to the directory, needs File::chdir

foreach my $file (@files) {
  next if ($file =~ /^\.+$/); # avoid folders . and ..
  next if ($0 =~ /$file/); # avoid moving this script if it is in the directory

  move($file, $pre . $file) or warn "Cannot rename file $file: $!";
}

Close all infowindows in Google Maps API v3

You should have to click your map - $('#map-selector').click();

Convert from java.util.date to JodaTime

java.util.Date date = ...
DateTime dateTime = new DateTime(date);

Make sure date isn't null, though, otherwise it acts like new DateTime() - I really don't like that.

Changing plot scale by a factor in matplotlib

As you have noticed, xscale and yscale does not support a simple linear re-scaling (unfortunately). As an alternative to Hooked's answer, instead of messing with the data, you can trick the labels like so:

ticks = ticker.FuncFormatter(lambda x, pos: '{0:g}'.format(x*scale))
ax.xaxis.set_major_formatter(ticks)

A complete example showing both x and y scaling:

import numpy as np
import pylab as plt
import matplotlib.ticker as ticker

# Generate data
x = np.linspace(0, 1e-9)
y = 1e3*np.sin(2*np.pi*x/1e-9) # one period, 1k amplitude

# setup figures
fig = plt.figure()
ax1 = fig.add_subplot(121)
ax2 = fig.add_subplot(122)
# plot two identical plots
ax1.plot(x, y)
ax2.plot(x, y)

# Change only ax2
scale_x = 1e-9
scale_y = 1e3
ticks_x = ticker.FuncFormatter(lambda x, pos: '{0:g}'.format(x/scale_x))
ax2.xaxis.set_major_formatter(ticks_x)

ticks_y = ticker.FuncFormatter(lambda x, pos: '{0:g}'.format(x/scale_y))
ax2.yaxis.set_major_formatter(ticks_y)

ax1.set_xlabel("meters")
ax1.set_ylabel('volt')
ax2.set_xlabel("nanometers")
ax2.set_ylabel('kilovolt')

plt.show() 

And finally I have the credits for a picture:

Left: ax1 no scaling, right: ax2 y axis scaled to kilo and x axis scaled to nano

Note that, if you have text.usetex: true as I have, you may want to enclose the labels in $, like so: '${0:g}$'.

How to make a new line or tab in <string> XML (eclipse/android)?

You can use \n for new line and \t for tabs. Also, extra spaces/tabs are just copied the way you write them in Strings.xml so just give a couple of spaces where ever you want them.

A better way to reach this would probably be using padding/margin in your view xml and splitting up your long text in different strings in your string.xml

Pass user defined environment variable to tomcat

In case of Windows, if you can't find setenv.bat, in the 2nd line of catalina.bat (after @echo off) add this:
SET APP_MASTER_PASSWORD=foo

May not be the best approach, but works

How to prevent Screen Capture in Android

According to this official guide, you can add WindowManager.LayoutParams.FLAG_SECURE to your window layout and it will disallow screenshots.

How to allow remote access to my WAMP server for Mobile(Android)

I assume you are using windows. Open the command prompt and type ipconfig and find out your local address (on your pc) it should look something like 192.168.1.13 or 192.168.0.5 where the end digit is the one that changes. It should be next to IPv4 Address.

If your WAMP does not use virtual hosts the next step is to enter that IP address on your phones browser ie http://192.168.1.13 If you have a virtual host then you will need root to edit the hosts file.

If you want to test the responsiveness / mobile design of your website you can change your user agent in chrome or other browsers to mimic a mobile.

See http://googlesystem.blogspot.co.uk/2011/12/changing-user-agent-new-google-chrome.html.

Edit: Chrome dev tools now has a mobile debug tool where you can change the size of the viewport, spoof user agents, connections (4G, 3G etc).

If you get forbidden access then see this question WAMP error: Forbidden You don't have permission to access /phpmyadmin/ on this server. Basically, change the occurrances of deny,allow to allow,deny in the httpd.conf file. You can access this by the WAMP menu.

To eliminate possible causes of the issue for now set your config file to

<Directory />
    Options FollowSymLinks
    AllowOverride All
    Order allow,deny
    Allow from all
    <RequireAll>
        Require all granted
    </RequireAll>
</Directory>

As thatis working for my windows PC, if you have the directory config block as well change that also to allow all.

Config file that fixed the problem:

https://gist.github.com/samvaughton/6790739

Problem was that the /www apache directory config block still had deny set as default and only allowed from localhost.

ASP.NET MVC - Attaching an entity of type 'MODELNAME' failed because another entity of the same type already has the same primary key value

Here what I did in the similar case.

That sitatuation means that same entity has already been existed in the context.So following can help

First check from ChangeTracker if the entity is in the context

var trackedEntries=GetContext().ChangeTracker.Entries<YourEntityType>().ToList();

var isAlreadyTracked =
                    trackedEntries.Any(trackedItem => trackedItem.Entity.Id ==myEntityToSave.Id);

If it exists

  if (isAlreadyTracked)
            {
                myEntityToSave= trackedEntries.First(trackedItem => trackedItem.Entity.Id == myEntityToSave.Id).Entity;
            } 

else
{
//Attach or Modify depending on your needs
}

How to add chmod permissions to file in Git?

According to official documentation, you can set or remove the "executable" flag on any tracked file using update-index sub-command.

To set the flag, use following command:

git update-index --chmod=+x path/to/file

To remove it, use:

git update-index --chmod=-x path/to/file

Under the hood

While this looks like the regular unix files permission system, actually it is not. Git maintains a special "mode" for each file in its internal storage:

  • 100644 for regular files
  • 100755 for executable ones

You can visualize it using ls-file subcommand, with --stage option:

$ git ls-files --stage
100644 aee89ef43dc3b0ec6a7c6228f742377692b50484 0       .gitignore
100755 0ac339497485f7cc80d988561807906b2fd56172 0       my_executable_script.sh

By default, when you add a file to a repository, Git will try to honor its filesystem attributes and set the correct filemode accordingly. You can disable this by setting core.fileMode option to false:

git config core.fileMode false

Troubleshooting

If at some point the Git filemode is not set but the file has correct filesystem flag, try to remove mode and set it again:

git update-index --chmod=-x path/to/file
git update-index --chmod=+x path/to/file

Bonus

Starting with Git 2.9, you can stage a file AND set the flag in one command:

git add --chmod=+x path/to/file

onCreateOptionsMenu inside Fragments

try this,

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.menu_sample, menu);
    super.onCreateOptionsMenu(menu,inflater);
}

Finally, in onCreateView method, add this line to make the options appear in your Toolbar

setHasOptionsMenu(true);

Correct way to use StringBuilder in SQL

When you already have all the "pieces" you wish to append, there is no point in using StringBuilder at all. Using StringBuilder and string concatenation in the same call as per your sample code is even worse.

This would be better:

return "select id1, " + " id2 " + " from " + " table";

In this case, the string concatenation is actually happening at compile-time anyway, so it's equivalent to the even-simpler:

return "select id1, id2 from table";

Using new StringBuilder().append("select id1, ").append(" id2 ")....toString() will actually hinder performance in this case, because it forces the concatenation to be performed at execution time, instead of at compile time. Oops.

If the real code is building a SQL query by including values in the query, then that's another separate issue, which is that you should be using parameterized queries, specifying the values in the parameters rather than in the SQL.

I have an article on String / StringBuffer which I wrote a while ago - before StringBuilder came along. The principles apply to StringBuilder in the same way though.

How can I make a clickable link in an NSAttributedString?

I found this really useful but I needed to do it in quite a few places so I've wrapped my approach up in a simple extension to NSMutableAttributedString:

Swift 3

extension NSMutableAttributedString {

    public func setAsLink(textToFind:String, linkURL:String) -> Bool {

        let foundRange = self.mutableString.range(of: textToFind)
        if foundRange.location != NSNotFound {
            self.addAttribute(.link, value: linkURL, range: foundRange)
            return true
        }
        return false
    }
}

Swift 2

import Foundation

extension NSMutableAttributedString {

   public func setAsLink(textToFind:String, linkURL:String) -> Bool {

       let foundRange = self.mutableString.rangeOfString(textToFind)
       if foundRange.location != NSNotFound {
           self.addAttribute(NSLinkAttributeName, value: linkURL, range: foundRange)
           return true
       }
       return false
   }
}

Example usage:

let attributedString = NSMutableAttributedString(string:"I love stackoverflow!")
let linkWasSet = attributedString.setAsLink("stackoverflow", linkURL: "http://stackoverflow.com")

if linkWasSet {
    // adjust more attributedString properties
}

Objective-C

I've just hit a requirement to do the same in a pure Objective-C project, so here's the Objective-C category.

@interface NSMutableAttributedString (SetAsLinkSupport)

- (BOOL)setAsLink:(NSString*)textToFind linkURL:(NSString*)linkURL;

@end


@implementation NSMutableAttributedString (SetAsLinkSupport)

- (BOOL)setAsLink:(NSString*)textToFind linkURL:(NSString*)linkURL {

     NSRange foundRange = [self.mutableString rangeOfString:textToFind];
     if (foundRange.location != NSNotFound) {
         [self addAttribute:NSLinkAttributeName value:linkURL range:foundRange];
         return YES;
     }
     return NO;
}

@end

Example usage:

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:"I love stackoverflow!"];

BOOL linkWasSet = [attributedString setAsLink:@"stackoverflow" linkURL:@"http://stackoverflow.com"];

if (linkWasSet) {
    // adjust more attributedString properties
}

Make Sure that the NSTextField's Behavior attribute is set as Selectable. Xcode NSTextField behavior attribute

Accessing member of base class

Working example. Notes below.

class Animal {
    constructor(public name) {
    }

    move(meters) {
        alert(this.name + " moved " + meters + "m.");
    }
}

class Snake extends Animal {
    move() {
        alert(this.name + " is Slithering...");
        super.move(5);
    }
}

class Horse extends Animal {
    move() {
        alert(this.name + " is Galloping...");
        super.move(45);
    }
}

var sam = new Snake("Sammy the Python");
var tom: Animal = new Horse("Tommy the Palomino");

sam.move();
tom.move(34);
  1. You don't need to manually assign the name to a public variable. Using public name in the constructor definition does this for you.

  2. You don't need to call super(name) from the specialised classes.

  3. Using this.name works.

Notes on use of super.

This is covered in more detail in section 4.9.2 of the language specification.

The behaviour of the classes inheriting from Animal is not dissimilar to the behaviour in other languages. You need to specify the super keyword in order to avoid confusion between a specialised function and the base class function. For example, if you called move() or this.move() you would be dealing with the specialised Snake or Horse function, so using super.move() explicitly calls the base class function.

There is no confusion of properties, as they are the properties of the instance. There is no difference between super.name and this.name - there is simply this.name. Otherwise you could create a Horse that had different names depending on whether you were in the specialized class or the base class.

Run a command shell in jenkins

Error shows that script does not exists

The file does not exists. check your full path

C:\Windows\TEMP\hudson6299483223982766034.sh
The system cannot find the file specified

Moreover, to launch .sh scripts into windows, you need to have CYGWIN installed and well configured into your path

Confirm that script exists.

Into jenkins script, do the following to confirm that you do have the file

cd C:\Windows\TEMP\
ls -rtl
sh -xe hudson6299483223982766034.sh

Using member variable in lambda capture list inside a member function

Summary of the alternatives:

capture this:

auto lambda = [this](){};

use a local reference to the member:

auto& tmp = grid;
auto lambda = [ tmp](){}; // capture grid by (a single) copy
auto lambda = [&tmp](){}; // capture grid by ref

C++14:

auto lambda = [ grid = grid](){}; // capture grid by copy
auto lambda = [&grid = grid](){}; // capture grid by ref

example: https://godbolt.org/g/dEKVGD

How to temporarily exit Vim and go back

To extend user Zen's answer, you could add the following line in your ~/.vimrc file to allow quick toggling between Bash and Vim:

noremap <C-d> :sh<cr>

What does the Java assert keyword do, and when should it be used?

Assertions are disabled by default. To enable them we must run the program with -ea options (granularity can be varied). For example, java -ea AssertionsDemo.

There are two formats for using assertions:

  1. Simple: eg. assert 1==2; // This will raise an AssertionError.
  2. Better: assert 1==2: "no way.. 1 is not equal to 2"; This will raise an AssertionError with the message given displayed too and is thus better. Although the actual syntax is assert expr1:expr2 where expr2 can be any expression returning a value, I have used it more often just to print a message.

QED symbol in latex

Add to doc header:

\usepackage{ amssymb }

Then at the desired location add:

$ \blacksquare $

Doctrine and LIKE query

You can use the createQuery method (direct in the controller) :

$query = $em->createQuery("SELECT o FROM AcmeCodeBundle:Orders o WHERE o.OrderMail =  :ordermail and o.Product like :searchterm")
->setParameter('searchterm', '%'.$searchterm.'%')
->setParameter('ordermail', '[email protected]');

You need to change AcmeCodeBundle to match your bundle name

Or even better - create a repository class for the entity and create a method in there - this will make it reusable

How to check a not-defined variable in JavaScript

We can check undefined as follows

var x; 

if (x === undefined) {
    alert("x is undefined");
} else {
     alert("x is defined");
}

Insert picture/table in R Markdown

In March I made a deck presentation in slidify, Rmarkdown with impress.js which is a cool 3D framework. My index.Rmdheader looks like

---
title       : French TER (regional train) monthly regularity
subtitle    : since January 2013
author      : brigasnuncamais
job         : Business Intelligence / Data Scientist consultant
framework   : impressjs     # {io2012, html5slides, shower, dzslides, ...}
highlighter : highlight.js  # {highlight.js, prettify, highlight}
hitheme     : tomorrow      # 
widgets     : []            # {mathjax, quiz, bootstrap}
mode        : selfcontained # {standalone, draft}
knit        : slidify::knit2slides

subdirs are:

/assets /css    /impress-demo.css
        /fig    /unnamed-chunk-1-1.png (generated by included R code)
        /img    /SS850452.png (my image used as background)
        /js     /impress.js
        /layouts/custbg.html # content:--- layout: slide --- {{{ slide.html }}}
        /libraries  /frameworks /impressjs
                                /io2012
                    /highlighters   /highlight.js
                                    /impress.js
index.Rmd

A slide with image in background code snippet would be in my .Rmd:

<div id="bg">
  <img src="assets/img/SS850452.png" alt="">
</div>  

Some issues appeared since I last worked on it (photos are no more in background, text it too large on my R plot) but it works fine on my local. Troubles come when I run it on RPubs.

How to add jQuery code into HTML Page

Make sure that you embedd the jQuery library into your page by adding the below shown line into your <head> block:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>

How can I check that JButton is pressed? If the isEnable() is not work?

Just do System.out.println(e.getActionCommand()); inside actionPerformed(ActionEvent e) function. This will tell you which command is just performed.

or

if(e.getActionCommand().equals("Add")){

   System.out.println("Add button pressed");
}

Save text file UTF-8 encoded with VBA

The traditional way to transform a string to a UTF-8 string is as follows:

StrConv("hello world",vbFromUnicode)

So put simply:

Dim fnum As Integer
fnum = FreeFile
Open "myfile.txt" For Output As fnum
Print #fnum, StrConv("special characters: äöüß", vbFromUnicode)
Close fnum

No special COM objects required

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

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

The number of sessions the database was configured to allow

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

The number of sessions currently active

SELECT COUNT(*)
  FROM v$session

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

Insert string at specified position

Try it, it will work for any number of substrings

<?php
    $string = 'bcadef abcdef';
    $substr = 'a';
    $attachment = '+++';

    //$position = strpos($string, 'a');

    $newstring = str_replace($substr, $substr.$attachment, $string);

    // bca+++def a+++bcdef
?>

html <input type="text" /> onchange event not working

A couple of comments that IMO are important:

  • input elements not not emitting 'change' event until USER action ENTER or blur await IS the correct behavior.

  • The event you want to use is "input" ("oninput"). Here is well demonstrated the different between the two: https://javascript.info/events-change-input

  • The two events signal two different user gestures/moments ("input" event means user is writing or navigating a select list options, but still didn't confirm the change. "change" means user did changed the value (with an enter or blur our)

  • Listening for key events like many here recommended is a bad practice in this case. (like people modifying the default behavior of ENTER on inputs)...

  • jQuery has nothing to do with this. This is all in HTML standard.

  • If you have problems understanding WHY this is the correct behavior, perhaps is helpful, as experiment, use your text editor or browser without a mouse/pad, just a keyboard.

My two cents.

Sort a list by multiple attributes?

There is a operator < between lists e.g.:

[12, 'tall', 'blue', 1] < [4, 'tall', 'blue', 13]

will give

False

Spaces cause split in path with PowerShell

There's a hack I've used since the Invoke-Expression works fine for me.

You could set the current location to the path with spaces, invoke the expression, get back to your previous location and continue:

$currLocation = Get-Location
Set-Location = "C:\Windows Services\"
Invoke-Expression ".\MyService.exe"
Set-Location $currLocation

This will only work if the exe doesn't have any spaces in its name.

Hope this helps

I'm getting Key error in python

A KeyError generally means the key doesn't exist. So, are you sure the path key exists?

From the official python docs:

exception KeyError

Raised when a mapping (dictionary) key is not found in the set of existing keys.

For example:

>>> mydict = {'a':'1','b':'2'}
>>> mydict['a']
'1'
>>> mydict['c']
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 'c'
>>>

So, try to print the content of meta_entry and check whether path exists or not.

>>> mydict = {'a':'1','b':'2'}
>>> print mydict
{'a': '1', 'b': '2'}

Or, you can do:

>>> 'a' in mydict
True
>>> 'c' in mydict
False

How to assign an exec result to a sql variable?

Here is solution for dynamic queries.

For example if you have more tables with different suffix:

dbo.SOMETHINGTABLE_ONE, dbo.SOMETHINGTABLE_TWO

Code:

DECLARE @INDEX AS NVARCHAR(20)
DECLARE @CheckVALUE AS NVARCHAR(max) = 'SELECT COUNT(SOMETHING) FROM 
dbo.SOMETHINGTABLE_'+@INDEX+''
DECLARE @tempTable Table (TempVALUE int)
DECLARE @RESULTVAL INT

INSERT INTO @tempTable
    EXEC sp_executesql @CheckVALUE

SET @RESULTVAL = (SELECT * FROM @tempTable)

DELETE @tempTable

SELECT @RESULTVAL 

npm WARN enoent ENOENT: no such file or directory, open 'C:\Users\Nuwanst\package.json'

Run command - npm init No file directory found issue got resolved

Errno 13 Permission denied Python

If you have this problem in Windows 10, and you know you have premisions on folder (You could write before but it just started to print exception PermissionError recently).. You will need to install Windows updates... I hope someone will help this info.

How to use sed to remove all double quotes within a file

Try this:

sed -i -e 's/\"//g' file.txt

Git merge is not possible because I have unmerged files

Another potential cause for this (Intellij was involved in my case, not sure that mattered though): trying to merge in changes from a main branch into a branch off of a feature branch.

In other words, merging "main" into "current" in the following arrangement:

main
  |
  --feature
      |
      --current

I resolved all conflicts and GiT reported unmerged files and I was stuck until I merged from main into feature, then feature into current.

Is there a “not in” operator in JavaScript for checking object properties?

As already said by Jordão, just negate it:

if (!(id in tutorTimes)) { ... }

Note: The above test if tutorTimes has a property with the name specified in id, anywhere in the prototype chain. For example "valueOf" in tutorTimes returns true because it is defined in Object.prototype.

If you want to test if a property doesn't exist in the current object, use hasOwnProperty:

if (!tutorTimes.hasOwnProperty(id)) { ... }

Or if you might have a key that is hasOwnPropery you can use this:

if (!Object.prototype.hasOwnProperty.call(tutorTimes,id)) { ... }

Reverse each individual word of "Hello World" string with Java

Using only substring() and recursion:

public String rev(String rest) {
    if (rest.equals(""))
        return "";
    return rev(rest.substring(1)) + rest.substring(0,1);
}

Android: Share plain text using intent (to all messaging apps)

Intent sendIntent = new Intent();
sendIntent.setAction(Intent.ACTION_SEND);
sendIntent.putExtra(Intent.EXTRA_TEXT, "This is my text to send.");
sendIntent.setType("text/plain");

Intent shareIntent = Intent.createChooser(sendIntent, null);
startActivity(shareIntent);

How do I import a .sql file in mysql database using PHP?

Grain Script is superb and save my day. Meanwhile mysql is depreciated and I rewrote Grain answer using PDO.

    $server  =  'localhost'; 
    $username   = 'root'; 
    $password   = 'your password';  
    $database = 'sample_db';

    /* PDO connection start */
    $conn = new PDO("mysql:host=$server; dbname=$database", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);         
    $conn->exec("SET CHARACTER SET utf8");     
    /* PDO connection end */

    // your config
    $filename = 'yourFile.sql';

    $maxRuntime = 8; // less then your max script execution limit


    $deadline = time()+$maxRuntime; 
    $progressFilename = $filename.'_filepointer'; // tmp file for progress
    $errorFilename = $filename.'_error'; // tmp file for erro



    ($fp = fopen($filename, 'r')) OR die('failed to open file:'.$filename);

    // check for previous error
    if( file_exists($errorFilename) ){
        die('<pre> previous error: '.file_get_contents($errorFilename));
    }

    // activate automatic reload in browser
    echo '<html><head> <meta http-equiv="refresh" content="'.($maxRuntime+2).'"><pre>';

    // go to previous file position
    $filePosition = 0;
    if( file_exists($progressFilename) ){
        $filePosition = file_get_contents($progressFilename);
        fseek($fp, $filePosition);
    }

    $queryCount = 0;
    $query = '';
    while( $deadline>time() AND ($line=fgets($fp, 1024000)) ){
        if(substr($line,0,2)=='--' OR trim($line)=='' ){
            continue;
        }

        $query .= $line;
        if( substr(trim($query),-1)==';' ){

            $igweze_prep= $conn->prepare($query);

            if(!($igweze_prep->execute())){ 
                $error = 'Error performing query \'<strong>' . $query . '\': ' . print_r($conn->errorInfo());
                file_put_contents($errorFilename, $error."\n");
                exit;
            }
            $query = '';
            file_put_contents($progressFilename, ftell($fp)); // save the current file position for 
            $queryCount++;
        }
    }

    if( feof($fp) ){
        echo 'dump successfully restored!';
    }else{
        echo ftell($fp).'/'.filesize($filename).' '.(round(ftell($fp)/filesize($filename), 2)*100).'%'."\n";
        echo $queryCount.' queries processed! please reload or wait for automatic browser refresh!';
    }

Division in Python 2.7. and 3.3

In Python 3, / is float division

In Python 2, / is integer division (assuming int inputs)

In both 2 and 3, // is integer division

(To get float division in Python 2 requires either of the operands be a float, either as 20. or float(20))

How to perform a for-each loop over all the files under a specified path?

The for-loop will iterate over each (space separated) entry on the provided string.

You do not actually execute the find command, but provide it is as string (which gets iterated by the for-loop). Instead of the double quotes use either backticks or $():

for line in $(find . -iname '*.txt'); do 
     echo "$line"
     ls -l "$line"
done

Furthermore, if your file paths/names contains spaces this method fails (since the for-loop iterates over space separated entries). Instead it is better to use the method described in dogbanes answer.


To clarify your error:

As said, for line in "find . -iname '*.txt'"; iterates over all space separated entries, which are:

  • find
  • .
  • -iname
  • '*.txt' (I think...)

The first two do not result in an error (besides the undesired behavior), but the third is problematic as it executes:

ls -l -iname

A lot of (bash) commands can combine single character options, so -iname is the same as -i -n -a -m -e. And voila: your invalid option -- 'e' error!

UIImage: Resize, then Crop

This is a version of Jane Sales' answer in Swift. Cheers!

public func resizeImage(image: UIImage, size: CGSize) -> UIImage? {
    var returnImage: UIImage?

    var scaleFactor: CGFloat = 1.0
    var scaledWidth = size.width
    var scaledHeight = size.height
    var thumbnailPoint = CGPointMake(0, 0)

    if !CGSizeEqualToSize(image.size, size) {
        let widthFactor = size.width / image.size.width
        let heightFactor = size.height / image.size.height

        if widthFactor > heightFactor {
            scaleFactor = widthFactor
        } else {
            scaleFactor = heightFactor
        }

        scaledWidth = image.size.width * scaleFactor
        scaledHeight = image.size.height * scaleFactor

        if widthFactor > heightFactor {
            thumbnailPoint.y = (size.height - scaledHeight) * 0.5
        } else if widthFactor < heightFactor {
            thumbnailPoint.x = (size.width - scaledWidth) * 0.5
        }
    }

    UIGraphicsBeginImageContextWithOptions(size, true, 0)

    var thumbnailRect = CGRectZero
    thumbnailRect.origin = thumbnailPoint
    thumbnailRect.size.width = scaledWidth
    thumbnailRect.size.height = scaledHeight

    image.drawInRect(thumbnailRect)
    returnImage = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()

    return returnImage
}

How do I make an HTML text box show a hint when empty?

You want to assign something like this to onfocus:

if (this.value == this.defaultValue)
    this.value = ''
this.className = ''

and this to onblur:

if (this.value == '')
    this.value = this.defaultValue
this.className = 'placeholder'

(You can use something a bit cleverer, like a framework function, to do the classname switching if you want.)

With some CSS like this:

input.placeholder{
    color: gray;
    font-style: italic;
}

How to solve npm error "npm ERR! code ELIFECYCLE"

The port is probably being used by another application, try listing and see if it's your application:

lsof -i:8080

You can kill the process of this port:

lsof -ti:8080 | xargs kill

Pandas Split Dataframe into two Dataframes at a specific row

iloc

df1 = datasX.iloc[:, :72]
df2 = datasX.iloc[:, 72:]

(iloc docs)

How do I check if PHP is connected to a database already?

Try using PHP's mysql_ping function:

echo @mysql_ping() ? 'true' : 'false';

You will need to prepend the "@" to suppose the MySQL Warnings you'll get for running this function without being connected to a database.

There are other ways as well, but it depends on the code that you're using.

jQuery.active function

This is a variable jQuery uses internally, but had no reason to hide, so it's there to use. Just a heads up, it becomes jquery.ajax.active next release. There's no documentation because it's exposed but not in the official API, lots of things are like this actually, like jQuery.cache (where all of jQuery.data() goes).

I'm guessing here by actual usage in the library, it seems to be there exclusively to support $.ajaxStart() and $.ajaxStop() (which I'll explain further), but they only care if it's 0 or not when a request starts or stops. But, since there's no reason to hide it, it's exposed to you can see the actual number of simultaneous AJAX requests currently going on.


When jQuery starts an AJAX request, this happens:

if ( s.global && ! jQuery.active++ ) {
  jQuery.event.trigger( "ajaxStart" );
}

This is what causes the $.ajaxStart() event to fire, the number of connections just went from 0 to 1 (jQuery.active++ isn't 0 after this one, and !0 == true), this means the first of the current simultaneous requests started. The same thing happens at the other end. When an AJAX request stops (because of a beforeSend abort via return false or an ajax call complete function runs):

if ( s.global && ! --jQuery.active ) {
  jQuery.event.trigger( "ajaxStop" );
}

This is what causes the $.ajaxStop() event to fire, the number of requests went down to 0, meaning the last simultaneous AJAX call finished. The other global AJAX handlers fire in there along the way as well.

How do I set session timeout of greater than 30 minutes

this will set your session to keep everything till the browser is closed

session.setMaxinactiveinterval(-1);

and this should set it for 1 day

session.setMaxInactiveInterval(60*60*24);

How to save select query results within temporary table?

You can also do the following:

CREATE TABLE #TEMPTABLE
(
    Column1 type1,
    Column2 type2,
    Column3 type3
)

INSERT INTO #TEMPTABLE
SELECT ...

SELECT *
FROM #TEMPTABLE ...

DROP TABLE #TEMPTABLE

use localStorage across subdomains

this kind of solution causes many problems like this. for consistency and SEO considerations redirect on the main domain is the best solution.

do it redirection at the server level

How To Redirect www to Non-www with Nginx

https://www.digitalocean.com/community/tutorials/how-to-redirect-www-to-non-www-with-nginx-on-centos-7

or any other level like route 53 if are using

How to define multiple CSS attributes in jQuery?

Pass it as an Object:

$(....).css({
    'property': 'value', 
    'property': 'value'
});

http://docs.jquery.com/CSS/css#properties

Uncaught TypeError: Cannot read property 'msie' of undefined

$.browser was removed from jQuery starting with version 1.9. It is now available as a plugin. It's generally recommended to avoid browser detection, which is why it was removed.

How to get coordinates of an svg element?

I was trying to select an area of svg with a rectangle and get all the elements from it. For this, element.getBoundingClientRect() worked perfectly for me. It returns current coordinates of svg elements regardless of whether svg is scaled or transformed.

Crop image in android

Can you use default android Crop functionality?

Here is my code

private void performCrop(Uri picUri) {
    try {
        Intent cropIntent = new Intent("com.android.camera.action.CROP");
        // indicate image type and Uri
        cropIntent.setDataAndType(picUri, "image/*");
        // set crop properties here
        cropIntent.putExtra("crop", true);
        // indicate aspect of desired crop
        cropIntent.putExtra("aspectX", 1);
        cropIntent.putExtra("aspectY", 1);
        // indicate output X and Y
        cropIntent.putExtra("outputX", 128);
        cropIntent.putExtra("outputY", 128);
        // retrieve data on return
        cropIntent.putExtra("return-data", true);
        // start the activity - we handle returning in onActivityResult
        startActivityForResult(cropIntent, PIC_CROP);
    }
    // respond to users whose devices do not support the crop action
    catch (ActivityNotFoundException anfe) {
        // display an error message
        String errorMessage = "Whoops - your device doesn't support the crop action!";
        Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT);
        toast.show();
    }
}

declare:

final int PIC_CROP = 1;

at top.

In onActivity result method, writ following code:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == PIC_CROP) {
        if (data != null) {
            // get the returned data
            Bundle extras = data.getExtras();
            // get the cropped bitmap
            Bitmap selectedBitmap = extras.getParcelable("data");

            imgView.setImageBitmap(selectedBitmap);
        }
    }
}

It is pretty easy for me to implement and also shows darken areas.

How can I view a git log of just one user's commits?

cat | git log --author="authorName" > author_commits_details.txt

This gives your commits in text format.

Concatenate strings from several rows using Pandas groupby

If you want to concatenate your "text" in a list:

df.groupby(['name', 'month'], as_index = False).agg({'text': list})

iPhone viewWillAppear not firing

Views are added "directly" by calling [view addSubview:subview]. Views are added "indirectly" by methods such as tab bars or nav bars that swap subviews.

Any time you call [view addSubview:subviewController.view], you should then call [subviewController viewWillAppear:NO] (or YES as your case may be).

I had this problem when I implemented my own custom root-view management system for a subscreen in a game. Manually adding the call to viewWillAppear cured my problem.

How can I list ALL DNS records?

In the absence of the ability to do zone transfers, I wrote this small bash script, dg:

#!/bin/bash
COMMON_SUBDOMAINS=(www mail smtp pop imap blog en ftp ssh login)
if [[ "$2" == "x" ]]; then
    dig +nocmd "$1" +noall +answer "${3:-any}"
    wild_ips="$(dig +short "*.$1" "${3:-any}" | tr '\n' '|')"
    wild_ips="${wild_ips%|}"
    for sub in "${COMMON_SUBDOMAINS[@]}"; do
        dig +nocmd "$sub.$1" +noall +answer "${3:-any}"
    done | grep -vE "${wild_ips}"
    dig +nocmd "*.$1" +noall +answer "${3:-any}"
else
    dig +nocmd "$1" +noall +answer "${2:-any}"
fi

Now I use dg example.com to get a nice, clean list of DNS records, or dg example.com x to include a bunch of other popular subdomains.

grep -vE "${wild_ips}" filters out records that could be the result of a wildcard DNS entry such as * 10800 IN A 1.38.216.82. Otherwise, a wildcard entry would make it appear as if there were records for each $COMMON_SUBDOMAN.

Note: This relies on ANY queries, which are blocked by some DNS providers such as CloudFlare.

Lodash - difference between .extend() / .assign() and .merge()

Another difference to pay attention to is handling of undefined values:

mergeInto = { a: 1}
toMerge = {a : undefined, b:undefined}
lodash.extend({}, mergeInto, toMerge) // => {a: undefined, b:undefined}
lodash.merge({}, mergeInto, toMerge)  // => {a: 1, b:undefined}

So merge will not merge undefined values into defined values.

Scrolling to an Anchor using Transition/CSS3

Just apply scroll behaviour to all elements with this one-line code:

_x000D_
_x000D_
*{
scroll-behavior: smooth !important;
}
_x000D_
_x000D_
_x000D_

HTTP Content-Type Header and JSON

The below code helps me to return a JSON object for JavaScript on the front end

My template code

template_file.json

{
    "name": "{{name}}"
}

Python backed code

def download_json(request):
    print("Downloading JSON")
    # Response render a template as JSON object
    return HttpResponse(render_to_response("template_file.json",dict(name="Alex Vera")),content_type="application/json")    

File url.py

url(r'^download_as_json/$', views.download_json, name='download_json-url')

jQuery code for the front end

  $.ajax({
        url:'{% url 'download_json-url' %}'        
    }).done(function(data){
        console.log('json ', data);
        console.log('Name', data.name);
        alert('hello ' + data.name);
    });

Rebuild all indexes in a Database

DECLARE @String NVARCHAR(MAX);
USE Databse Name;
SELECT @String
    =
(
    SELECT 'ALTER INDEX [' + dbindexes.[name] + '] ON [' + db.name + '].[' + dbschemas.[name] + '].[' + dbtables.[name]
           + '] REBUILD PARTITION = ALL WITH (DATA_COMPRESSION = PAGE);' + CHAR(10) AS [text()]
    FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, NULL) AS indexstats
        INNER JOIN sys.tables dbtables
            ON dbtables.[object_id] = indexstats.[object_id]
        INNER JOIN sys.schemas dbschemas
            ON dbtables.[schema_id] = dbschemas.[schema_id]
        INNER JOIN sys.indexes AS dbindexes
            ON dbindexes.[object_id] = indexstats.[object_id]
               AND indexstats.index_id = dbindexes.index_id
        INNER JOIN sys.databases AS db
            ON db.database_id = indexstats.database_id
    WHERE dbindexes.name IS NOT NULL
          AND indexstats.database_id = DB_ID()
          AND indexstats.avg_fragmentation_in_percent >= 10
    ORDER BY indexstats.page_count DESC
    FOR XML PATH('')
);
EXEC (@String);

SELECT last id, without INSERT

In MySQL, this does return the highest value from the id column:

SELECT MAX(id) FROM tablename;

However, this does not put that id into $n:

$n = mysql_query("SELECT max(id) FROM tablename");

To get the value, you need to do this:

$result = mysql_query("SELECT max(id) FROM tablename");

if (!$result) {
    die('Could not query:' . mysql_error());
}

$id = mysql_result($result, 0, 'id');

If you want to get the last insert ID from A, and insert it into B, you can do it with one command:

INSERT INTO B (col) SELECT MAX(id) FROM A;

Nesting await in Parallel.ForEach

svick's answer is (as usual) excellent.

However, I find Dataflow to be more useful when you actually have large amounts of data to transfer. Or when you need an async-compatible queue.

In your case, a simpler solution is to just use the async-style parallelism:

var ids = new List<string>() { "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" };

var customerTasks = ids.Select(i =>
  {
    ICustomerRepo repo = new CustomerRepo();
    return repo.GetCustomer(i);
  });
var customers = await Task.WhenAll(customerTasks);

foreach (var customer in customers)
{
  Console.WriteLine(customer.ID);
}

Console.ReadKey();

List files ONLY in the current directory

import os
for subdir, dirs, files in os.walk('./'):
    for file in files:
      do some stuff
      print file

You can improve this code with del dirs[:]which will be like following .

import os
for subdir, dirs, files in os.walk('./'):
    del dirs[:]
    for file in files:
      do some stuff
      print file

Or even better if you could point os.walk with current working directory .

import os
cwd = os.getcwd()
for subdir, dirs, files in os.walk(cwd, topdown=True):
    del dirs[:]  # remove the sub directories.
    for file in files:
      do some stuff
      print file

What's the difference between using "let" and "var"?

ES6 introduced two new keyword(let and const) alternate to var.

When you need a block level deceleration you can go with let and const instead of var.

The below table summarize the difference between var, let and const

enter image description here

jQuery to serialize only elements within a div

Try also this:

$('#divId').find('input').serialize()

while-else-loop

Wrap the "set" statement to mean "set if not set" and put it naked above the while loop.

You are correct, the language does not provide what you're looking for in exactly that syntax, but that's because there are programming paradigms like the one I just suggested so you don't need the syntax you are proposing.

Sending command line arguments to npm script

If you want to pass arguments to the middle of an npm script, as opposed to just having them appended to the end, then inline environment variables seem to work nicely:

"scripts": {
  "dev": "BABEL_ARGS=-w npm run build && cd lib/server && nodemon index.js",
  "start": "npm run build && node lib/server/index.js",
  "build": "mkdir -p lib && babel $BABEL_ARGS -s inline --stage 0 src -d lib",
},

Here, npm run dev passes the -w watch flag to babel, but npm run start just runs a regular build once.

POST data with request module on Node.JS

I have to get the data from a POST method of the PHP code. What worked for me was:

const querystring = require('querystring');
const request = require('request');

const link = 'http://your-website-link.com/sample.php';
let params = { 'A': 'a', 'B': 'b' };

params = querystring.stringify(params); // changing into querystring eg 'A=a&B=b'

request.post({
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' }, // important to interect with PHP
  url: link,
  body: params,
}, function(error, response, body){
  console.log(body);
});

Unloading classes in java?

I wrote a custom classloader, from which it is possible to unload individual classes without GCing the classloader. Jar Class Loader

Java, List only subdirectories from a directory, not files

A very simple Java 8 solution:

File[] directories = new File("/your/path/").listFiles(File::isDirectory);

It's equivalent to using a FileFilter (works with older Java as well):

File[] directories = new File("/your/path/").listFiles(new FileFilter() {
    @Override
    public boolean accept(File file) {
        return file.isDirectory();
    }
});

Print list without brackets in a single row

I don't know if this is efficient as others but simple logic always works:

import sys
name = ["Sam", "Peter", "James", "Julian", "Ann"]
for i in range(0, len(names)):
    sys.stdout.write(names[i])
    if i != len(names)-1:
        sys.stdout.write(", ")

Output:

Sam, Peter, James, Julian, Ann

How to set HTTP header to UTF-8 using PHP which is valid in W3C validator?

PHP sends headers automatically if set up to use internal encoding:

ini_set('default_charset', 'utf-8');

Retrieve WordPress root directory path?

For retrieving the path you can use a function <?php $path = get_home_path(); ?>. I do not want to just repeat what had been already said here, but I want to add one more thing:

If you are using windows server, which is rare case for WordPress installation, but still happens sometimes, you might face a problem with the path output. It might miss a "\" somewhere and you will get an error if you will be using such a path. So when outputting make sure to sanitize the path:

<?php 

$path = get_home_path(); 
$path = wp_normalize_path ($path);

// now $path is ready to be used :)

?>

Preventing scroll bars from being hidden for MacOS trackpad users in WebKit/Blink

For a one-page web application where I add scrollable sections dynamically, I trigger OSX's scrollbars by programmatically scrolling one pixel down and back up:

// Plain JS:
var el = document.getElementById('scrollable-section');
el.scrollTop = 1;
el.scrollTop = 0;

// jQuery:
$('#scrollable-section').scrollTop(1).scrollTop(0);

This triggers the visual cue fading in and out.

Move cursor to end of file in vim

Try doing SHIFT + G and you will be at the end of the page, but you can't edit yet. Go to the top by doing G + G

How to set a cookie to expire in 1 hour in Javascript?

You can write this in a more compact way:

var now = new Date();
now.setTime(now.getTime() + 1 * 3600 * 1000);
document.cookie = "name=value; expires=" + now.toUTCString() + "; path=/";

And for someone like me, who wasted an hour trying to figure out why the cookie with expiration is not set up (but without expiration can be set up) in Chrome, here is in answer:

For some strange reason Chrome team decided to ignore cookies from local pages. So if you do this on localhost, you will not be able to see your cookie in Chrome. So either upload it on the server or use another browser.

Returning an array using C

You can do it using heap memory (through malloc() invocation) like other answers reported here, but you must always manage the memory (use free() function everytime you call your function). You can also do it with a static array:

char* returnArrayPointer() 
{
static char array[SIZE];

// do something in your array here

return array; 
}

You can than use it without worrying about memory management.

int main() 
{
char* myArray = returnArrayPointer();
/* use your array here */
/* don't worry to free memory here */
}

In this example you must use static keyword in array definition to set to application-long the array lifetime, so it will not destroyed after return statement. Of course, in this way you occupy SIZE bytes in your memory for the entire application life, so size it properly!

Disabling enter key for form

I checked all the above solutions, they don't work. The only possible solution is to catch 'onkeydown' event for each input of the form. You need to attach disableAllInputs to onload of the page or via jquery ready()

/*
 * Prevents default behavior of pushing enter button. This method doesn't work,
 * if bind it to the 'onkeydown' of the document|form, or to the 'onkeypress' of
 * the input. So method should be attached directly to the input 'onkeydown'
 */
function preventEnterKey(e) {
    // W3C (Chrome|FF) || IE
    e = e || window.event;
    var keycode = e.which || e.keyCode;
    if (keycode == 13) { // Key code of enter button
        // Cancel default action
        if (e.preventDefault) { // W3C
            e.preventDefault();
        } else { // IE
            e.returnValue = false;
        }
        // Cancel visible action
        if (e.stopPropagation) { // W3C
            e.stopPropagation();
        } else { // IE
            e.cancelBubble = true;
        }
        // We don't need anything else
        return false;
    }
}
/* Disable enter key for all inputs of the document */
function disableAllInputs() {
    try {
        var els = document.getElementsByTagName('input');
        if (els) {
            for ( var i = 0; i < els.length; i++) {
                els[i].onkeydown = preventEnterKey;
            }
        }
    } catch (e) {
    }
}

Problems when trying to load a package in R due to rJava

I had a similar problem what worked for me was to set JAVA_HOME. I tired it first in R:

Sys.setenv(JAVA_HOME = "C:/Program Files/Java/jdk1.8.0_101/")

And when it actually worked I set it in

System Properties -> Advanced -> Environment Variables

by adding a new System variable. I then restarted R/RStudio and everything worked.

Clang vs GCC for my Linux Development project

I use both because sometimes they give different, useful error messages.

The Python project was able to find and fix a number of small buglets when one of the core developers first tried compiling with clang.

PHP-FPM doesn't write to error log

There are multiple php config files, but THIS is the one you need to edit:

/etc/php(version)?/fpm/pool.d/www.conf

uncomment the line that says:

catch_workers_output

That will allow PHPs stderr to go to php-fpm's error log instead of /dev/null.

How to do IF NOT EXISTS in SQLite

You can also set a Constraint on a Table with the KEY fields and set On Conflict "Ignore"

When an applicable constraint violation occurs, the IGNORE resolution algorithm skips the one row that contains the constraint violation and continues processing subsequent rows of the SQL statement as if nothing went wrong. Other rows before and after the row that contained the constraint violation are inserted or updated normally. No error is returned when the IGNORE conflict resolution algorithm is used.

SQLite Documentation

AngularJS passing data to $http.get request

Here's a complete example of an HTTP GET request with parameters using angular.js in ASP.NET MVC:

CONTROLLER:

public class AngularController : Controller
{
    public JsonResult GetFullName(string name, string surname)
    {
        System.Diagnostics.Debugger.Break();
        return Json(new { fullName = String.Format("{0} {1}",name,surname) }, JsonRequestBehavior.AllowGet);
    }
}

VIEW:

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular.min.js"></script>
<script type="text/javascript">
    var myApp = angular.module("app", []);

    myApp.controller('controller', function ($scope, $http) {

        $scope.GetFullName = function (employee) {

            //The url is as follows - ControllerName/ActionName?name=nameValue&surname=surnameValue

            $http.get("/Angular/GetFullName?name=" + $scope.name + "&surname=" + $scope.surname).
            success(function (data, status, headers, config) {
                alert('Your full name is - ' + data.fullName);
            }).
            error(function (data, status, headers, config) {
                alert("An error occurred during the AJAX request");
            });

        }
    });

</script>

<div ng-app="app" ng-controller="controller">

    <input type="text" ng-model="name" />
    <input type="text" ng-model="surname" />
    <input type="button" ng-click="GetFullName()" value="Get Full Name" />
</div>

How do you test your Request.QueryString[] variables?

I do have functions for each (actually it's one small class, with lots of statics):

  • GetIntegerFromQuerystring(val)
  • GetIntegerFromPost(val)
  • ....

It returns -1 if fails (which is almost always OK for me, I have some other functions for negative numbers as well).

Dim X as Integer = GetIntegerFromQuerystring("id")
If x = -1 Then Exit Sub

How do I find out what License has been applied to my SQL Server installation?

This shows the licence type and number of licences:

SELECT SERVERPROPERTY('LicenseType'), SERVERPROPERTY('NumLicenses')

The character encoding of the HTML document was not declared

Your initial page is a complete HTML page containing a form, the contents of which are posted to insert.php when the submit button is clicked, but insert.php needs to process the form's contents and do something with them, like add them to a database, or output them to a new page. Your current insert.php just outputs the contents of the title field, so your browser tries to interpret that as an HTML page, and fails, obviously, because it isn't valid HTML (i.e. it isn't contained in an 'HTML' tag, etc.).

Your insert.php needs to output the necessary HTML, and insert the form data in there somewhere.

For example:

<?php 

   $title = $_POST["title"];
   $price = $_POST["price"];

  echo '<html xmlns="http://www.w3.org/1999/xhtml">';
  echo '<head>';
  echo '<meta http-equiv="content-type" content="text/html; charset=utf-8" />';
  echo '<title>';
  echo $title;
  echo '</title>';
  echo '</head>';
  echo '<body>';
  echo 'Hello, world.';
  echo '</body>';

 ?>

How to set a Javascript object values dynamically?

myObj.name=value

or

myObj['name']=value     (Quotes are required)

Both of these are interchangeable.

Edit: I'm guessing you meant myObj[prop] = value, instead of myObj[name] = value. Second syntax works fine: http://jsfiddle.net/waitinforatrain/dNjvb/1/

Exporting to .xlsx using Microsoft.Office.Interop.Excel SaveAs Error

myBook.Saved = true;
myBook.SaveCopyAs(xlsFileName);
myBook.Close(null, null, null);
myExcel.Workbooks.Close();
myExcel.Quit();

Undefined reference to `pow' and `floor'

All answers above are incomplete, the problem here lies in linker ld rather than compiler collect2: ld returned 1 exit status. When you are compiling your fib.c to object:

$ gcc -c fib.c
$ nm fib.o
0000000000000028 T fibo
                 U floor
                 U _GLOBAL_OFFSET_TABLE_
0000000000000000 T main
                 U pow
                 U printf

Where nm lists symbols from object file. You can see that this was compiled without an error, but pow, floor, and printf functions have undefined references, now if I will try to link this to executable:

$ gcc fib.o
fib.o: In function `fibo':
fib.c:(.text+0x57): undefined reference to `pow'
fib.c:(.text+0x84): undefined reference to `floor'
collect2: error: ld returned 1 exit status

Im getting similar output you get. To solve that, I need to tell linker where to look for references to pow, and floor, for this purpose I will use linker -l flag with m which comes from libm.so library.

$ gcc fib.o -lm
$ nm a.out
0000000000201010 B __bss_start
0000000000201010 b completed.7697
                 w __cxa_finalize@@GLIBC_2.2.5
0000000000201000 D __data_start
0000000000201000 W data_start
0000000000000620 t deregister_tm_clones
00000000000006b0 t __do_global_dtors_aux
0000000000200da0 t 
__do_global_dtors_aux_fini_array_entry
0000000000201008 D __dso_handle
0000000000200da8 d _DYNAMIC
0000000000201010 D _edata
0000000000201018 B _end
0000000000000722 T fibo
0000000000000804 T _fini
                 U floor@@GLIBC_2.2.5
00000000000006f0 t frame_dummy
0000000000200d98 t __frame_dummy_init_array_entry
00000000000009a4 r __FRAME_END__
0000000000200fa8 d _GLOBAL_OFFSET_TABLE_
                 w __gmon_start__
000000000000083c r __GNU_EH_FRAME_HDR
0000000000000588 T _init
0000000000200da0 t __init_array_end
0000000000200d98 t __init_array_start
0000000000000810 R _IO_stdin_used
                 w _ITM_deregisterTMCloneTable
                 w _ITM_registerTMCloneTable
0000000000000800 T __libc_csu_fini
0000000000000790 T __libc_csu_init
                 U __libc_start_main@@GLIBC_2.2.5
00000000000006fa T main
                 U pow@@GLIBC_2.2.5
                 U printf@@GLIBC_2.2.5
0000000000000660 t register_tm_clones
00000000000005f0 T _start
0000000000201010 D __TMC_END__

You can now see, functions pow, floor are linked to GLIBC_2.2.5.

Parameters order is important too, unless your system is configured to use shared librares by default, my system is not, so when I issue:

$ gcc -lm fib.o
fib.o: In function `fibo':
fib.c:(.text+0x57): undefined reference to `pow'
fib.c:(.text+0x84): undefined reference to `floor'
collect2: error: ld returned 1 exit status

Note -lm flag before object file. So in conclusion, add -lm flag after all other flags, and parameters, to be sure.

jQuery - how to check if an element exists?

if ($("#MyId").length) { ... write some code here ...}

This from will automatically check for the presence of the element and will return true if an element exists.

jQuery: Handle fallback for failed AJAX Request

Dougs answer is correct, but you actually can use $.getJSON and catch errors (not having to use $.ajax). Just chain the getJSON call with a call to the fail function:

$.getJSON('/foo/bar.json')
    .done(function() { alert('request successful'); })
    .fail(function() { alert('request failed'); });

Live demo: http://jsfiddle.net/NLDYf/5/

This behavior is part of the jQuery.Deferred interface.
Basically it allows you to attach events to an asynchronous action after you call that action, which means you don't have to pass the event function to the action.

Read more about jQuery.Deferred here: http://api.jquery.com/category/deferred-object/

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

Even tried all suggestions, in my case (Office x64 - Visual Studio 2017), the only way to have both access engines on a Office 64x installation so you can use it on Visual Studio and using a 2016+ version of Office, is to install the 2010 version of the Engine.

First install the x64 from this page

https://www.microsoft.com/en-us/download/details.aspx?id=54920

and then the x86 version from this one

https://www.microsoft.com/en-us/download/details.aspx?id=13255

as from this blog: http://dinesql.blogspot.com/2017/10/microsoft-access-database-engine-2016-Redistributable-Setup-you-cannot-install-the-32-bit-version-You-cannot-install-the-64-bit-version.html

How do I correctly clean up a Python object?

As an appendix to Clint's answer, you can simplify PackageResource using contextlib.contextmanager:

@contextlib.contextmanager
def packageResource():
    class Package:
        ...
    package = Package()
    yield package
    package.cleanup()

Alternatively, though probably not as Pythonic, you can override Package.__new__:

class Package(object):
    def __new__(cls, *args, **kwargs):
        @contextlib.contextmanager
        def packageResource():
            # adapt arguments if superclass takes some!
            package = super(Package, cls).__new__(cls)
            package.__init__(*args, **kwargs)
            yield package
            package.cleanup()

    def __init__(self, *args, **kwargs):
        ...

and simply use with Package(...) as package.

To get things shorter, name your cleanup function close and use contextlib.closing, in which case you can either use the unmodified Package class via with contextlib.closing(Package(...)) or override its __new__ to the simpler

class Package(object):
    def __new__(cls, *args, **kwargs):
        package = super(Package, cls).__new__(cls)
        package.__init__(*args, **kwargs)
        return contextlib.closing(package)

And this constructor is inherited, so you can simply inherit, e.g.

class SubPackage(Package):
    def close(self):
        pass

Insert data through ajax into mysql database

The available answers led to the fact that I entered empty values into the database. I corrected this error by replacing the serialize () function with the following code.

$(document).ready(function(){

// When click the button.
$("#button").click(function() {

    // Assigning Variables to Form Fields
    var email = $("#email").val();

    // Send the form data using the ajax method
    $.ajax({
        data: "email=" + email,
        type: "post",
        url: "your_file.php",
        success: function(data){
            alert("Data Save: " + data);
        }
    });

});

});

Regular expression for number with length of 4, 5 or 6

Try this:

^[0-9]{4,6}$

{4,6} = between 4 and 6 characters, inclusive.

How to deal with http status codes other than 200 in Angular 2

Include required imports and you can make ur decision in handleError method Error status will give the error code

import { HttpClient, HttpErrorResponse } from '@angular/common/http';
import {Observable, throwError} from "rxjs/index";
import { catchError, retry } from 'rxjs/operators';
import {ApiResponse} from "../model/api.response";
import { TaxType } from '../model/taxtype.model'; 

private handleError(error: HttpErrorResponse) {
if (error.error instanceof ErrorEvent) {
  // A client-side or network error occurred. Handle it accordingly.
  console.error('An error occurred:', error.error.message);
} else {
  // The backend returned an unsuccessful response code.
  // The response body may contain clues as to what went wrong,
  console.error(
    `Backend returned code ${error.status}, ` +
    `body was: ${error.error}`);
}
// return an observable with a user-facing error message
return throwError(
  'Something bad happened; please try again later.');
  };

  getTaxTypes() : Observable<ApiResponse> {
return this.http.get<ApiResponse>(this.baseUrl).pipe(
  catchError(this.handleError)
);
  }

Update a local branch with the changes from a tracked remote branch

You have set the upstream of that branch

(see:

git branch -f --track my_local_branch origin/my_remote_branch
# OR (if my_local_branch is currently checked out):
$ git branch --set-upstream-to my_local_branch origin/my_remote_branch

(git branch -f --track won't work if the branch is checked out: use the second command git branch --set-upstream-to instead, or you would get "fatal: Cannot force update the current branch.")

That means your branch is already configured with:

branch.my_local_branch.remote origin
branch.my_local_branch.merge my_remote_branch

Git already has all the necessary information.
In that case:

# if you weren't already on my_local_branch branch:
git checkout my_local_branch 
# then:
git pull

is enough.


If you hadn't establish that upstream branch relationship when it came to push your 'my_local_branch', then a simple git push -u origin my_local_branch:my_remote_branch would have been enough to push and set the upstream branch.
After that, for the subsequent pulls/pushes, git pull or git push would, again, have been enough.

How to make a GUI for bash scripts?

Before actually using GUI dialogues, consider using console prompts. Quite often you can get away with simple "y/n?" prompts, which in bash you achieve via the read command..

read -p "Do something? ";
if [ $REPLY == "y" ]; then
    echo yay;
fi

If console prompt's just won't cut it, Zenity is really easy to use, for example:

      zenity --error --text="Testing..."
      zenity --question --text="Continue?"

This only works on Linux/Gnome (or rather, it'll only be installed by default on such systems). The read method will work on pretty much any platform (including headless machines, or via SSH)

If you need anything more complex than what read or Zenity provides, "change to C++" is really the best method (although I'd recommend Python/Ruby over C++ for such shell-script-replacement tasks)

I want to do simple interface for some strange game, the progress bar for health or something is the example for what I want. Variable "HEALTH" is 34, so make progress bar filled in 34/100

As a command-line script, it'd use Python:

$ export HEALTH=34
$ python -c "import os; print '*' * int(os.environ.get('HEALTH', 0))"
**********************************

Or to normalise the values between 1 and 78 (so you don't get line-wrapping on a standard terminal size):

$ python -c "import os; print '*' * int((int(os.environ.get('HEALTH', 0)) / 100.0) * 78)"

Zenity also has a Progress Dialog,

#!/bin/sh
(
echo "10" ; sleep 1
echo "# Updating mail logs" ; sleep 1
echo "20" ; sleep 1
echo "# Resetting cron jobs" ; sleep 1
echo "50" ; sleep 1
echo "This line will just be ignored" ; sleep 1
echo "75" ; sleep 1
echo "# Rebooting system" ; sleep 1
echo "100" ; sleep 1
) |
zenity --progress \
  --title="Update System Logs" \
  --text="Scanning mail logs..." \
  --percentage=0

if [ "$?" = -1 ] ; then
        zenity --error \
          --text="Update canceled."
fi

As I said before, if Zenity cannot do what you need, look into writing your game-thing as a "proper" script in Python/Ruby/Perl/C++/etc as it sounds like you're pushing the bounds of what a shell-script can do..

Get string after character

echo "GenFiltEff=7.092200e-01" | cut -d "=" -f2 

Remote debugging a Java application

Answer covering Java >= 9:

For Java 9+, the JVM option needs a slight change by prefixing the address with the IP address of the machine hosting the JVM, or just *:

-agentlib:jdwp=transport=dt_socket,server=y,address=*:8000,suspend=n

This is due to a change noted in https://www.oracle.com/technetwork/java/javase/9-notes-3745703.html#JDK-8041435.

For Java < 9, the port number is enough to connect.

load csv into 2D matrix with numpy for plotting

Pure numpy

numpy.loadtxt(open("test.csv", "rb"), delimiter=",", skiprows=1)

Check out the loadtxt documentation.

You can also use python's csv module:

import csv
import numpy
reader = csv.reader(open("test.csv", "rb"), delimiter=",")
x = list(reader)
result = numpy.array(x).astype("float")

You will have to convert it to your favorite numeric type. I guess you can write the whole thing in one line:

result = numpy.array(list(csv.reader(open("test.csv", "rb"), delimiter=","))).astype("float")

Added Hint:

You could also use pandas.io.parsers.read_csv and get the associated numpy array which can be faster.

How to update fields in a model without creating a new record in django?

Sometimes it may be required to execute the update atomically that is using one update request to the database without reading it first.

Also get-set attribute-save may cause problems if such updates may be done concurrently or if you need to set the new value based on the old field value.

In such cases query expressions together with update may by useful:

TemperatureData.objects.filter(id=1).update(value=F('value') + 1)

How to get response from S3 getObject in Node.js?

When doing a getObject() from the S3 API, per the docs the contents of your file are located in the Body property, which you can see from your sample output. You should have code that looks something like the following

const aws = require('aws-sdk');
const s3 = new aws.S3(); // Pass in opts to S3 if necessary

var getParams = {
    Bucket: 'abc', // your bucket name,
    Key: 'abc.txt' // path to the object you're looking for
}

s3.getObject(getParams, function(err, data) {
    // Handle any error and exit
    if (err)
        return err;

  // No error happened
  // Convert Body from a Buffer to a String

  let objectData = data.Body.toString('utf-8'); // Use the encoding necessary
});

You may not need to create a new buffer from the data.Body object but if you need you can use the sample above to achieve that.

Remove all of x axis labels in ggplot

You have to set to element_blank() in theme() elements you need to remove

ggplot(data = diamonds, mapping = aes(x = clarity)) + geom_bar(aes(fill = cut))+
  theme(axis.title.x=element_blank(),
        axis.text.x=element_blank(),
        axis.ticks.x=element_blank())

Convert URL to File or Blob for FileReader.readAsDataURL

Add cors mode to prevent files cors blocked

fetch(url,{mode:"cors"})
                    .then(res => res.blob())
                    .then(blob => {
                        const file = new File([blob], 'dot.png', {type:'image/png'});
                        console.log(file);
                    });

How to extract public key using OpenSSL?

For AWS importing an existing public key,

  1. Export from the .pem doing this... (on linux)

    openssl rsa -in ./AWSGeneratedKey.pem -pubout -out PublicKey.pub
    

This will produce a file which if you open in a text editor looking something like this...

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAn/8y3uYCQxSXZ58OYceG
A4uPdGHZXDYOQR11xcHTrH13jJEzdkYZG8irtyG+m3Jb6f9F8WkmTZxl+4YtkJdN
9WyrKhxq4Vbt42BthadX3Ty/pKkJ81Qn8KjxWoL+SMaCGFzRlfWsFju9Q5C7+aTj
eEKyFujH5bUTGX87nULRfg67tmtxBlT8WWWtFe2O/wedBTGGQxXMpwh4ObjLl3Qh
bfwxlBbh2N4471TyrErv04lbNecGaQqYxGrY8Ot3l2V2fXCzghAQg26Hc4dR2wyA
PPgWq78db+gU3QsePeo2Ki5sonkcyQQQlCkL35Asbv8khvk90gist4kijPnVBCuv
cwIDAQAB
-----END PUBLIC KEY-----
  1. However AWS will NOT accept this file.

    You have to strip off the -----BEGIN PUBLIC KEY----- and -----END PUBLIC KEY----- from the file. Save it and import and it should work in AWS.

How to install pip in CentOS 7?

On CentOS 7, the pip version is pip3.4 and is located here:

/usr/local/bin/pip3.4

How to connect to a remote Git repository?

Now, if the repository is already existing on a remote machine, and you do not have anything locally, you do git clone instead.

The URL format is simple, it is PROTOCOL:/[user@]remoteMachineAddress/path/to/repository.git

For example, cloning a repository on a machine to which you have SSH access using the "dev" user, residing in /srv/repositories/awesomeproject.git and that machine has the ip 10.11.12.13 you do:

git clone ssh://[email protected]/srv/repositories/awesomeproject.git

How to convert a Java String to an ASCII byte array?

There is only one character wrong in the code you tried:

Charset characterSet = Charset.forName("US-ASCII");
String string = "Wazzup";
byte[] bytes = String.getBytes(characterSet);
               ^

Notice the upper case "String". This tries to invoke a static method on the string class, which does not exist. Instead you need to invoke the method on your string instance:

byte[] bytes = string.getBytes(characterSet);

Jenkins - passing variables between jobs?

(for fellow googlers)

If you are building a serious pipeline with the Build Flow Plugin, you can pass parameters between jobs with the DSL like this :

Supposing an available string parameter "CVS_TAG", in order to pass it to other jobs :

build("pipeline_begin", CVS_TAG: params['CVS_TAG'])
parallel (
   // will be scheduled in parallel.
   { build("pipeline_static_analysis", CVS_TAG: params['CVS_TAG']) },
   { build("pipeline_nonreg", CVS_TAG: params['CVS_TAG']) }
)
// will be triggered after previous jobs complete
build("pipeline_end", CVS_TAG: params['CVS_TAG'])

Hint for displaying available variables / params :

// output values
out.println '------------------------------------'
out.println 'Triggered Parameters Map:'
out.println params
out.println '------------------------------------'
out.println 'Build Object Properties:'
build.properties.each { out.println "$it.key -> $it.value" }
out.println '------------------------------------'

Html.Textbox VS Html.TextboxFor

The TextBoxFor is a newer MVC input extension introduced in MVC2.

The main benefit of the newer strongly typed extensions is to show any errors / warnings at compile-time rather than runtime.

See this page.

http://weblogs.asp.net/scottgu/archive/2010/01/10/asp-net-mvc-2-strongly-typed-html-helpers.aspx

How to pass an object from one activity to another on Android

While calling an activity

Intent intent = new Intent(fromClass.this,toClass.class).putExtra("myCustomerObj",customerObj);

In toClass.java receive the activity by

Customer customerObjInToClass = getIntent().getExtras().getParcelable("myCustomerObj");

Please make sure that customer class implements parcelable

public class Customer implements Parcelable {

    private String firstName, lastName, address;
    int age;

    /* all your getter and setter methods */

    public Customer(Parcel in ) {
        readFromParcel( in );
    }

    public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
        public LeadData createFromParcel(Parcel in ) {
            return new Customer( in );
        }

        public Customer[] newArray(int size) {
            return new Customer[size];
        }
    };


    @Override
    public void writeToParcel(Parcel dest, int flags) {

        dest.writeString(firstName);
        dest.writeString(lastName);
        dest.writeString(address);
        dest.writeInt(age);
    }

    private void readFromParcel(Parcel in ) {

        firstName = in .readString();
        lastName  = in .readString();
        address   = in .readString();
        age       = in .readInt();
    }

Sending and Receiving SMS and MMS in Android (pre Kit Kat Android 4.4)

SmsListenerClass

public class SmsListener extends BroadcastReceiver {

static final String ACTION =
        "android.provider.Telephony.SMS_RECEIVED";

@Override
public void onReceive(Context context, Intent intent) {

    Log.e("RECEIVED", ":-:-" + "SMS_ARRIVED");

    // TODO Auto-generated method stub
    if (intent.getAction().equals(ACTION)) {

        Log.e("RECEIVED", ":-" + "SMS_ARRIVED");

        StringBuilder buf = new StringBuilder();
        Bundle bundle = intent.getExtras();
        if (bundle != null) {

            Object[] pdus = (Object[]) bundle.get("pdus");

            SmsMessage[] messages = new SmsMessage[pdus.length];
            SmsMessage message = null;

            for (int i = 0; i < messages.length; i++) {

                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                    String format = bundle.getString("format");
                    messages[i] = SmsMessage.createFromPdu((byte[]) pdus[i], format);
                } else {
                    messages[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);
                }

                message = messages[i];
                buf.append("Received SMS from  ");
                buf.append(message.getDisplayOriginatingAddress());
                buf.append(" - ");
                buf.append(message.getDisplayMessageBody());
            }

            MainActivity inst = MainActivity.instance();
            inst.updateList(message.getDisplayOriginatingAddress(),message.getDisplayMessageBody());

        }

        Log.e("RECEIVED:", ":" + buf.toString());

        Toast.makeText(context, "RECEIVED SMS FROM :" + buf.toString(), Toast.LENGTH_LONG).show();

    }
}

Activity

@Override
public void onStart() {
    super.onStart();
    inst = this;
}

public static MainActivity instance() {
    return inst;
}

public void updateList(final String msg_from, String msg_body) {

    tvMessage.setText(msg_from + " :- " + msg_body);

    sendSMSMessage(msg_from, msg_body);

}

protected void sendSMSMessage(String phoneNo, String message) {

    try {
        SmsManager smsManager = SmsManager.getDefault();
        smsManager.sendTextMessage(phoneNo, null, message, null, null);
        Toast.makeText(getApplicationContext(), "SMS sent.", Toast.LENGTH_LONG).show();
    } catch (Exception e) {
        Toast.makeText(getApplicationContext(), "SMS faild, please try again.", Toast.LENGTH_LONG).show();
        e.printStackTrace();
    }
}

Manifest

<uses-permission android:name="android.permission.RECEIVE_SMS"/>
<uses-permission android:name="android.permission.READ_SMS" />
<uses-permission android:name="android.permission.SEND_SMS"/>

<receiver android:name=".SmsListener">
        <intent-filter>
            <action android:name="android.provider.Telephony.SMS_RECEIVED" />
        </intent-filter>
    </receiver>

Android Material: Status bar color won't change

As others have also mentioned, this can be readily solved by adding the following to the onCreate() of the Activity:

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
        getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
        getWindow().setStatusBarColor(ContextCompat.getColor(this, R.color.primary_dark));
    }

However, the important point I want to add here is that in some cases, even the above does not change the status bar color. For example, when using MikePenz library for Navigation Drawer, it implicityly overrides the status bar color, so that you need to manually add the following for it to work:

.withStatusBarColorRes(R.color.status_bar_color)

How do I get the raw request body from the Request.Content object using .net 4 api endpoint

You can get the raw data by calling ReadAsStringAsAsync on the Request.Content property.

string result = await Request.Content.ReadAsStringAsync();

There are various overloads if you want it in a byte or in a stream. Since these are async-methods you need to make sure your controller is async:

public async Task<IHttpActionResult> GetSomething()
{
    var rawMessage = await Request.Content.ReadAsStringAsync();
    // ...
    return Ok();
}

EDIT: if you're receiving an empty string from this method, it means something else has already read it. When it does that, it leaves the pointer at the end. An alternative method of doing this is as follows:

public IHttpActionResult GetSomething()
{
    var reader = new StreamReader(Request.Body);
    reader.BaseStream.Seek(0, SeekOrigin.Begin); 
    var rawMessage = reader.ReadToEnd();

    return Ok();
}

In this case, your endpoint doesn't need to be async (unless you have other async-methods)

difference between variables inside and outside of __init__()

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

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

The result will be like this:

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

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

This is all you should know about that specific variables.

"Find next" in Vim

When I was beginning I needed to watch a demo.

How to search in Vim

  1. type /
  2. type search term e.g. "var"
  3. press enter
  4. for next instance press n (for previous N)

What is the minimum I have to do to create an RPM file?

If make config works for your program or you have a shell script which copies your two files to the appropriate place you can use checkinstall. Just go to the directory where your makefile is in and call it with the parameter -R (for RPM) and optionally with the installation script.

HTML5 Canvas Resize (Downscale) Image High Quality?

Since your problem is to downscale your image, there is no point in talking about interpolation -which is about creating pixel-. The issue here is downsampling.

To downsample an image, we need to turn each square of p * p pixels in the original image into a single pixel in the destination image.

For performances reasons Browsers do a very simple downsampling : to build the smaller image, they will just pick ONE pixel in the source and use its value for the destination. which 'forgets' some details and adds noise.

Yet there's an exception to that : since the 2X image downsampling is very simple to compute (average 4 pixels to make one) and is used for retina/HiDPI pixels, this case is handled properly -the Browser does make use of 4 pixels to make one-.

BUT... if you use several time a 2X downsampling, you'll face the issue that the successive rounding errors will add too much noise.
What's worse, you won't always resize by a power of two, and resizing to the nearest power + a last resizing is very noisy.

What you seek is a pixel-perfect downsampling, that is : a re-sampling of the image that will take all input pixels into account -whatever the scale-.
To do that we must compute, for each input pixel, its contribution to one, two, or four destination pixels depending wether the scaled projection of the input pixels is right inside a destination pixels, overlaps an X border, an Y border, or both.
( A scheme would be nice here, but i don't have one. )

Here's an example of canvas scale vs my pixel perfect scale on a 1/3 scale of a zombat.

Notice that the picture might get scaled in your Browser, and is .jpegized by S.O..
Yet we see that there's much less noise especially in the grass behind the wombat, and the branches on its right. The noise in the fur makes it more contrasted, but it looks like he's got white hairs -unlike source picture-.
Right image is less catchy but definitively nicer.

enter image description here

Here's the code to do the pixel perfect downscaling :

fiddle result : http://jsfiddle.net/gamealchemist/r6aVp/embedded/result/
fiddle itself : http://jsfiddle.net/gamealchemist/r6aVp/

// scales the image by (float) scale < 1
// returns a canvas containing the scaled image.
function downScaleImage(img, scale) {
    var imgCV = document.createElement('canvas');
    imgCV.width = img.width;
    imgCV.height = img.height;
    var imgCtx = imgCV.getContext('2d');
    imgCtx.drawImage(img, 0, 0);
    return downScaleCanvas(imgCV, scale);
}

// scales the canvas by (float) scale < 1
// returns a new canvas containing the scaled image.
function downScaleCanvas(cv, scale) {
    if (!(scale < 1) || !(scale > 0)) throw ('scale must be a positive number <1 ');
    var sqScale = scale * scale; // square scale = area of source pixel within target
    var sw = cv.width; // source image width
    var sh = cv.height; // source image height
    var tw = Math.floor(sw * scale); // target image width
    var th = Math.floor(sh * scale); // target image height
    var sx = 0, sy = 0, sIndex = 0; // source x,y, index within source array
    var tx = 0, ty = 0, yIndex = 0, tIndex = 0; // target x,y, x,y index within target array
    var tX = 0, tY = 0; // rounded tx, ty
    var w = 0, nw = 0, wx = 0, nwx = 0, wy = 0, nwy = 0; // weight / next weight x / y
    // weight is weight of current source point within target.
    // next weight is weight of current source point within next target's point.
    var crossX = false; // does scaled px cross its current px right border ?
    var crossY = false; // does scaled px cross its current px bottom border ?
    var sBuffer = cv.getContext('2d').
    getImageData(0, 0, sw, sh).data; // source buffer 8 bit rgba
    var tBuffer = new Float32Array(3 * tw * th); // target buffer Float32 rgb
    var sR = 0, sG = 0,  sB = 0; // source's current point r,g,b
    /* untested !
    var sA = 0;  //source alpha  */    

    for (sy = 0; sy < sh; sy++) {
        ty = sy * scale; // y src position within target
        tY = 0 | ty;     // rounded : target pixel's y
        yIndex = 3 * tY * tw;  // line index within target array
        crossY = (tY != (0 | ty + scale)); 
        if (crossY) { // if pixel is crossing botton target pixel
            wy = (tY + 1 - ty); // weight of point within target pixel
            nwy = (ty + scale - tY - 1); // ... within y+1 target pixel
        }
        for (sx = 0; sx < sw; sx++, sIndex += 4) {
            tx = sx * scale; // x src position within target
            tX = 0 |  tx;    // rounded : target pixel's x
            tIndex = yIndex + tX * 3; // target pixel index within target array
            crossX = (tX != (0 | tx + scale));
            if (crossX) { // if pixel is crossing target pixel's right
                wx = (tX + 1 - tx); // weight of point within target pixel
                nwx = (tx + scale - tX - 1); // ... within x+1 target pixel
            }
            sR = sBuffer[sIndex    ];   // retrieving r,g,b for curr src px.
            sG = sBuffer[sIndex + 1];
            sB = sBuffer[sIndex + 2];

            /* !! untested : handling alpha !!
               sA = sBuffer[sIndex + 3];
               if (!sA) continue;
               if (sA != 0xFF) {
                   sR = (sR * sA) >> 8;  // or use /256 instead ??
                   sG = (sG * sA) >> 8;
                   sB = (sB * sA) >> 8;
               }
            */
            if (!crossX && !crossY) { // pixel does not cross
                // just add components weighted by squared scale.
                tBuffer[tIndex    ] += sR * sqScale;
                tBuffer[tIndex + 1] += sG * sqScale;
                tBuffer[tIndex + 2] += sB * sqScale;
            } else if (crossX && !crossY) { // cross on X only
                w = wx * scale;
                // add weighted component for current px
                tBuffer[tIndex    ] += sR * w;
                tBuffer[tIndex + 1] += sG * w;
                tBuffer[tIndex + 2] += sB * w;
                // add weighted component for next (tX+1) px                
                nw = nwx * scale
                tBuffer[tIndex + 3] += sR * nw;
                tBuffer[tIndex + 4] += sG * nw;
                tBuffer[tIndex + 5] += sB * nw;
            } else if (crossY && !crossX) { // cross on Y only
                w = wy * scale;
                // add weighted component for current px
                tBuffer[tIndex    ] += sR * w;
                tBuffer[tIndex + 1] += sG * w;
                tBuffer[tIndex + 2] += sB * w;
                // add weighted component for next (tY+1) px                
                nw = nwy * scale
                tBuffer[tIndex + 3 * tw    ] += sR * nw;
                tBuffer[tIndex + 3 * tw + 1] += sG * nw;
                tBuffer[tIndex + 3 * tw + 2] += sB * nw;
            } else { // crosses both x and y : four target points involved
                // add weighted component for current px
                w = wx * wy;
                tBuffer[tIndex    ] += sR * w;
                tBuffer[tIndex + 1] += sG * w;
                tBuffer[tIndex + 2] += sB * w;
                // for tX + 1; tY px
                nw = nwx * wy;
                tBuffer[tIndex + 3] += sR * nw;
                tBuffer[tIndex + 4] += sG * nw;
                tBuffer[tIndex + 5] += sB * nw;
                // for tX ; tY + 1 px
                nw = wx * nwy;
                tBuffer[tIndex + 3 * tw    ] += sR * nw;
                tBuffer[tIndex + 3 * tw + 1] += sG * nw;
                tBuffer[tIndex + 3 * tw + 2] += sB * nw;
                // for tX + 1 ; tY +1 px
                nw = nwx * nwy;
                tBuffer[tIndex + 3 * tw + 3] += sR * nw;
                tBuffer[tIndex + 3 * tw + 4] += sG * nw;
                tBuffer[tIndex + 3 * tw + 5] += sB * nw;
            }
        } // end for sx 
    } // end for sy

    // create result canvas
    var resCV = document.createElement('canvas');
    resCV.width = tw;
    resCV.height = th;
    var resCtx = resCV.getContext('2d');
    var imgRes = resCtx.getImageData(0, 0, tw, th);
    var tByteBuffer = imgRes.data;
    // convert float32 array into a UInt8Clamped Array
    var pxIndex = 0; //  
    for (sIndex = 0, tIndex = 0; pxIndex < tw * th; sIndex += 3, tIndex += 4, pxIndex++) {
        tByteBuffer[tIndex] = Math.ceil(tBuffer[sIndex]);
        tByteBuffer[tIndex + 1] = Math.ceil(tBuffer[sIndex + 1]);
        tByteBuffer[tIndex + 2] = Math.ceil(tBuffer[sIndex + 2]);
        tByteBuffer[tIndex + 3] = 255;
    }
    // writing result to canvas.
    resCtx.putImageData(imgRes, 0, 0);
    return resCV;
}

It is quite memory greedy, since a float buffer is required to store the intermediate values of the destination image (-> if we count the result canvas, we use 6 times the source image's memory in this algorithm).
It is also quite expensive, since each source pixel is used whatever the destination size, and we have to pay for the getImageData / putImageDate, quite slow also.
But there's no way to be faster than process each source value in this case, and situation is not that bad : For my 740 * 556 image of a wombat, processing takes between 30 and 40 ms.

Convert a row of a data frame to vector

When you extract a single row from a data frame you get a one-row data frame. Convert it to a numeric vector:

as.numeric(df[1,])

As @Roland suggests, unlist(df[1,]) will convert the one-row data frame to a numeric vector without dropping the names. Therefore unname(unlist(df[1,])) is another, slightly more explicit way to get to the same result.

As @Josh comments below, if you have a not-completely-numeric (alphabetic, factor, mixed ...) data frame, you need as.character(df[1,]) instead.

How to set Oracle's Java as the default Java in Ubuntu?

If you want to use specific version of Java when multiple JDKs are installed, just setting JAVA_HOME may not work.

You need to use sudo update-alternatives --config java to set default Java.

Refer to https://askubuntu.com/questions/121654/how-to-set-default-java-version.

encapsulation vs abstraction real world example

Let me give my 2 cents of a real-world example-analogy close to IT.

Lets say you have a subscription site, e.g a wordpress site

Each user has a role, eg admin, subscriber and so on. Many users can be admins, subscribers etc..

So abstraction here is reflected in the fact that any user with admin role can do a set of things, it does not matter which specific user this is (this is an example of abstraction).

On the other hand, subscriber users do not have access to certain settings of the site, thus some internals of the application are encapsulated for plain subscribers (this is an example of encapsulation)

As one can see abstraction and encapsulation are relative concepts, they apply with respect to something specific.

One can follow this line of reasoning and explain polymoprhism and inheritance.

For example super-admin users could do all the things admin users could do, plus some more. Moreover, if admin roles get an update in functionality, super-admins would get the same update. Thus one can see here an example of inheritance, in that super-admin roles inherit all the properties of admin roles and extend them. Note that for most part of the site, admins are interchangeable with super-admins (meaning a super-admin user can easily be used in place of an admin user, but not vice-versa in general).

Chart.js canvas resize

I had to use a combination of multiple answers here with some minor tweaks.

First, it is necessary that you wrap the canvas element within a block-level container. I say to you, do not let the canvas element have any siblings; let it be a lonely child, for it is stubborn and spoiled. (The wrapper may not need any sizing restrictions placed on it, but for safety it may be good to have a max-height applied to it.)

After assuring that the previous conditions are met, when initiating the chart, make sure the following options are used:

var options = { 
    "responsive": true,
    "maintainAspectRatio": false
}

If you want to adjust the height of the chart, do so at the canvas element level.

<canvas height="500"></canvas>

Do not try to deal with the child in any other manner. This should result in a satisfyingly, properly laid-out chart, one that stays in its crib peacefully.

iPhone Debugging: How to resolve 'failed to get the task for process'?

Yes , Provisioning profiles which are for distribution purpose, i.e. Distrutions provisioning profiles do not support debugging and gives this error. Simply create and use debug provisioning profile (take care of this when creating provisioning profile from developer.apple.com account).

Git - fatal: Unable to create '/path/my_project/.git/index.lock': File exists

A restart of the machine worked for me. None of the solutions provided so far worked for me.

Env Windows 10 + Git Bash

EDIT: I see the same solution was here: git index.lock File exists when I try to commit, but cannot delete the file

ReactJS - .JS vs .JSX

As already mentioned, there is no difference, if you create a file with .jsx or .js.

I would like to bring another expect of creating the files as .jsx while creating a component.

This is not mandatory, but an architectural approach that we can follow. So, in large projects we divide our components as Presentational components or Container components. Just to brief, in container components we write the logic to get data for the component and render the Presentational component with props. In presentational components, we usually donot write functional logic, presentational components are used to represent the UI with required props.

So, if you check the definition on JSX in React documents.

It says,

const element = <h1>Hello, world!</h1>;

It is called JSX, and it is a syntax extension to JavaScript. 
We recommend using it with React to describe what the UI should look like. 
JSX may remind you of a template language, but it comes with the full power of JavaScript.

JSX produces React “elements”. Instead of artificially separating technologies by putting
markup and logic in separate files, React separates concerns with loosely coupled units 
called “components” that contain both. 

React doesn’t require using JSX, but most people find it helpful as a visual aid when 
working with UI inside the JavaScript code. It also allows React to show more useful 
error and warning messages.

It means, It's not mandatory but you can think of creating presentational components with '.jsx' as it actually binds the props with the UI. and container components, as .js files as those contains logic to get the data.

It's a convention that you can follow while creating the .jsx or .js files, to logically and physically separate the code.

AngularJS. How to call controller function from outside of controller component

I would rather include the factory as dependencies on the controllers than inject them with their own line of code: http://jsfiddle.net/XqDxG/550/

myModule.factory('mySharedService', function($rootScope) {
    return sharedService = {thing:"value"};
});

function ControllerZero($scope, mySharedService) {
    $scope.thing = mySharedService.thing;

ControllerZero.$inject = ['$scope', 'mySharedService'];

String.Replace ignoring case

(Edited: wasn't aware of the `naked link' problem, sorry about that)

Taken from here:

string myString = "find Me and replace ME";
string strReplace = "me";
myString = Regex.Replace(myString, "me", strReplace, RegexOptions.IgnoreCase);

Seems you are not the first to complain of the lack of case insensitive string.Replace.

Find and replace Android studio

Use ctrl+R or cmd+R in OSX

How to increase size of DOSBox window?

  • go to dosbox installation directory (on my machine that is C:\Program Files (x86)\DOSBox-0.74 ) as you see the version number is part of the installation directory name.

  • run "DOSBox 0.74 Options.bat"

  • the script starts notepad with configuration file: here change

    windowresolution=1600x800

    output=ddraw

(the resolution can't be changed if output=surface - that's the default).

  • safe configuration file changes.

How to finish current activity in Android

I found many answers but not one is simple... I hope this will help you...

try{
    Intent intent = new Intent(CurrentActivity.this, NewActivity.class);
    startActivity(intent);
} finally {
    finish();
}

so, Very simple logic is here, as we know that in java we write code that has some chances of exception in a try block and handle that exception in catch block but in finally block we write code that has to be executed in any cost (Either the exception comes or not).

Why does the html input with type "number" allow the letter 'e' to be entered in the field?

We can make it So simple like below

_x000D_
_x000D_
<input type="number"  onkeydown="javascript: return event.keyCode == 69 ? false : true" />
_x000D_
_x000D_
_x000D_

Updated Answer

we can make it even more simple as @88 MPG suggests

_x000D_
_x000D_
<input type="number" onkeydown="return event.keyCode !== 69" />
_x000D_
_x000D_
_x000D_

how to add key value pair in the JSON object already declared

Could you do the following:

obj = {
    "1":"aa",
    "2":"bb"
};


var newNum = "3";
var newVal = "cc";


obj[newNum] = newVal;



alert(obj["3"]); // this would alert 'cc'

How to set a time zone (or a Kind) of a DateTime value?

You can try this as well, it is easy to implement

TimeZone time2 = TimeZone.CurrentTimeZone;
DateTime test = time2.ToUniversalTime(DateTime.Now);
var singapore = TimeZoneInfo.FindSystemTimeZoneById("Singapore Standard Time");
var singaporetime = TimeZoneInfo.ConvertTimeFromUtc(test, singapore);

Change the text to which standard time you want to change.

Use TimeZone feature of C# to implement.

iTerm 2: How to set keyboard shortcuts to jump to beginning/end of line?

I see there's a lot of good answers already, but this should provide the closest to native OSX functionality as possible in more than just your shell. I verified that this works in ZSH, Bash, node, python -i, iex and irb/pry sessions (using rb-readline gem for readline, but should work for all).

Open the iTerm preferences ?+, and navigate to the Profiles tab (the Keys tab can be used, but adding keybinding to your profile allows you to save your profile and sync it to multiple computers) and keys sub-tab and enter the following:

Delete all characters left of the cursor

?+?Delete Send Hex Codes:

0x15 More compatible, but functionality sometimes is to delete the entire line rather than just the characters to the left of the curser. I personally use this and then overwrite my zsh bindkey for ^U to delete only stuff to the left of the cursor (see below).

or

0x18 0x7f Less compatible, doesn't work in node and won't work in zsh by default, see below to fix zsh (bash/irb/pry should be fine), performs desired functionality when it does work.

Delete all characters right of the cursor

?+fn+?Delete or ?+Delete? Send Hex Codes: 0x0b

Delete one word to left of cursor

?+?Delete Send Hex Codes:

0x1b 0x08 Breaks in Elixir's IEX, seems to work fine everywhere else

or

0x17 Works everywhere, but doesn't stop at normal word breaks in IRB and will instead delete until it sees a literal space.

Delete one word to right of cursor

?+fn?Delete or ?+Delete? Send Hex Codes: 0x1b 0x64

Move cursor to the front of line

?+? Send Hex Codes: 0x01

Move cursor to the end of line

?+? Send Hex Codes: 0x05

Move cursor one word left

?+? Send Hex Codes: 0x1b 0x62

Move cursor one word right

?+? Send Hex Codes: 0x1b 0x66

Undo

?+z Send Hex Codes: 0x1f

Redo typically not bound in bash, zsh or readline, so we can set it to a unused hexcode which we can then fix in zsh

?+?+Z or ?+y Send Hex Codes: 0x18 0x1f

Now how to fix any that don't work

For zsh, you can setup binding for the not yet functional ?+?Delete and ?+?+Z/?+y by running:

# changes hex 0x15 to delete everything to the left of the cursor,
# rather than the whole line
$ echo 'bindkey "^U" backward-kill-line' >> ~/.zshrc

# binds hex 0x18 0x7f with deleting everything to the left of the cursor
$ echo 'bindkey "^X\\x7f" backward-kill-line' >> ~/.zshrc

# adds redo
$ echo 'bindkey "^X^_" redo' >> ~/.zshrc

# reload your .zshrc for changes to take effect
$ source ~/.zshrc

I'm unable to find a solution for adding redo in bash or readline, so if anyone know a solution for either of those, please comment below and I'll try to add them in.

For anyone looking for the lookup table on how to convert key sequences to hex, I find this table very helpful.

Checking oracle sid and database name

The V$ views are mainly dynamic views of system metrics. They are used for performance tuning, session monitoring, etc. So access is limited to DBA users by default, which is why you're getting ORA-00942.

The easiest way of finding the database name is:

select * from global_name;

This view is granted to PUBLIC, so anybody can query it.

Change action bar color in android

ActionBar bar = getActionBar();
bar.setBackgroundDrawable(new ColorDrawable("COLOR")); 

it worked for me here

XPath:: Get following Sibling

You should be looking for the second tr that has the td that equals ' Color Digest ', then you need to look at either the following sibling of the first td in the tr, or the second td.

Try the following:

//tr[td='Color Digest'][2]/td/following-sibling::td[1]

or

//tr[td='Color Digest'][2]/td[2]

http://www.xpathtester.com/saved/76bb0bca-1896-43b7-8312-54f924a98a89

How to get current timestamp in string format in Java? "yyyy.MM.dd.HH.mm.ss"

Replace

new Timestamp();

with

new java.util.Date()

because there is no default constructor for Timestamp, or you can do it with the method:

new Timestamp(System.currentTimeMillis());

C#: How to make pressing enter in a text box trigger a button, yet still allow shortcuts such as "Ctrl+A" to get through?

If you want the return to trigger an action only when the user is in the textbox, you can assign the desired button the AcceptButton control, like this.

    private void textBox_Enter(object sender, EventArgs e)
    {
        ActiveForm.AcceptButton = Button1; // Button1 will be 'clicked' when user presses return
    }

    private void textBox_Leave(object sender, EventArgs e)
    {
        ActiveForm.AcceptButton = null; // remove "return" button behavior
    }

Try reinstalling `node-sass` on node 0.12?

You need to use the right version. Try:

nvm use 0.12

How to determine if a number is positive or negative?

I think there is a very simple solution:

public boolean isPositive(int|float|double|long i){
    return (((i-i)==0)? true : false);
}

tell me if I'm wrong!

Which HTML elements can receive focus?

The ally.js accessibility library provides an unofficial, test-based list here:

https://allyjs.io/data-tables/focusable.html

(NB: Their page doesn't say how often tests were performed.)

Array String Declaration

You are not initializing your String[]. You either need to initialize it using the exact array size, as suggested by @Tr?nSiLong, or use a List<String> and then convert to a String[] (in case you do not know the length):

String[] title = {
        "Abundance",
        "Anxiety",
        "Bruxism",
        "Discipline",
        "Drug Addiction"
    };
String urlbase = "http://www.somewhere.com/data/";
String imgSel = "/logo.png";
List<String> mStrings = new ArrayList<String>();

for(int i=0;i<title.length;i++) {
    mStrings.add(urlbase + title[i].toLowerCase() + imgSel);

    System.out.println(mStrings[i]);
}

String[] strings = new String[mStrings.size()];
strings = mStrings.toArray(strings);//now strings is the resulting array

How to implement band-pass Butterworth filter with Scipy.signal.butter

You could skip the use of buttord, and instead just pick an order for the filter and see if it meets your filtering criterion. To generate the filter coefficients for a bandpass filter, give butter() the filter order, the cutoff frequencies Wn=[low, high] (expressed as the fraction of the Nyquist frequency, which is half the sampling frequency) and the band type btype="band".

Here's a script that defines a couple convenience functions for working with a Butterworth bandpass filter. When run as a script, it makes two plots. One shows the frequency response at several filter orders for the same sampling rate and cutoff frequencies. The other plot demonstrates the effect of the filter (with order=6) on a sample time series.

from scipy.signal import butter, lfilter


def butter_bandpass(lowcut, highcut, fs, order=5):
    nyq = 0.5 * fs
    low = lowcut / nyq
    high = highcut / nyq
    b, a = butter(order, [low, high], btype='band')
    return b, a


def butter_bandpass_filter(data, lowcut, highcut, fs, order=5):
    b, a = butter_bandpass(lowcut, highcut, fs, order=order)
    y = lfilter(b, a, data)
    return y


if __name__ == "__main__":
    import numpy as np
    import matplotlib.pyplot as plt
    from scipy.signal import freqz

    # Sample rate and desired cutoff frequencies (in Hz).
    fs = 5000.0
    lowcut = 500.0
    highcut = 1250.0

    # Plot the frequency response for a few different orders.
    plt.figure(1)
    plt.clf()
    for order in [3, 6, 9]:
        b, a = butter_bandpass(lowcut, highcut, fs, order=order)
        w, h = freqz(b, a, worN=2000)
        plt.plot((fs * 0.5 / np.pi) * w, abs(h), label="order = %d" % order)

    plt.plot([0, 0.5 * fs], [np.sqrt(0.5), np.sqrt(0.5)],
             '--', label='sqrt(0.5)')
    plt.xlabel('Frequency (Hz)')
    plt.ylabel('Gain')
    plt.grid(True)
    plt.legend(loc='best')

    # Filter a noisy signal.
    T = 0.05
    nsamples = T * fs
    t = np.linspace(0, T, nsamples, endpoint=False)
    a = 0.02
    f0 = 600.0
    x = 0.1 * np.sin(2 * np.pi * 1.2 * np.sqrt(t))
    x += 0.01 * np.cos(2 * np.pi * 312 * t + 0.1)
    x += a * np.cos(2 * np.pi * f0 * t + .11)
    x += 0.03 * np.cos(2 * np.pi * 2000 * t)
    plt.figure(2)
    plt.clf()
    plt.plot(t, x, label='Noisy signal')

    y = butter_bandpass_filter(x, lowcut, highcut, fs, order=6)
    plt.plot(t, y, label='Filtered signal (%g Hz)' % f0)
    plt.xlabel('time (seconds)')
    plt.hlines([-a, a], 0, T, linestyles='--')
    plt.grid(True)
    plt.axis('tight')
    plt.legend(loc='upper left')

    plt.show()

Here are the plots that are generated by this script:

Frequency response for several filter orders

enter image description here

Convert array of integers to comma-separated string

int[] arr = new int[5] {1,2,3,4,5};

You can use Linq for it

String arrTostr = arr.Select(a => a.ToString()).Aggregate((i, j) => i + "," + j);

How to post pictures to instagram using API

There is no API to post photo to instagram using API , But there is a simple way is that install google extension " User Agent " it will covert your browser to android mobile chrome version . Here is the extension link https://chrome.google.com/webstore/detail/user-agent-switcher/clddifkhlkcojbojppdojfeeikdkgiae?utm_source=chrome-ntp-icon

just click on extension icon and choose chrome for android and open Instagram.com

Is there an equivalent to e.PageX position for 'touchstart' event as there is for click event?

I use this simple function for JQuery based project

    var pointerEventToXY = function(e){
      var out = {x:0, y:0};
      if(e.type == 'touchstart' || e.type == 'touchmove' || e.type == 'touchend' || e.type == 'touchcancel'){
        var touch = e.originalEvent.touches[0] || e.originalEvent.changedTouches[0];
        out.x = touch.pageX;
        out.y = touch.pageY;
      } else if (e.type == 'mousedown' || e.type == 'mouseup' || e.type == 'mousemove' || e.type == 'mouseover'|| e.type=='mouseout' || e.type=='mouseenter' || e.type=='mouseleave') {
        out.x = e.pageX;
        out.y = e.pageY;
      }
      return out;
    };

example:

$('a').on('mousedown touchstart', function(e){
  console.log(pointerEventToXY(e)); // will return obj ..kind of {x:20,y:40}
})

hope this will be usefull for you ;)

Simple and fast method to compare images for similarity

Does the screenshot contain only the icon? If so, the L2 distance of the two images might suffice. If the L2 distance doesn't work, the next step is to try something simple and well established, like: Lucas-Kanade. Which I'm sure is available in OpenCV.

Read Excel sheet in Powershell

There is the possibility of making something really more cool!

# Powershell 
$xl = new-object -ComObject excell.application
$doc=$xl.workbooks.open("Filepath")
$doc.Sheets.item(1).rows |
% { ($_.value2 | Select-Object -first 3 | Select-Object -last 2) -join "," }