Programs & Examples On #Tilde

How do I get HTTP Request body content in Laravel?

I don't think you want the data from your Request, I think you want the data from your Response. The two are different. Also you should build your response correctly in your controller.

Looking at the class in edit #2, I would make it look like this:

class XmlController extends Controller
{
    public function index()
    {
        $content = Request::all();
        return Response::json($content);
    }
}

Once you've gotten that far you should check the content of your response in your test case (use print_r if necessary), you should see the data inside.

More information on Laravel responses here:

http://laravel.com/docs/5.0/responses

What's the difference between tilde(~) and caret(^) in package.json?

See the NPM docs and semver docs:

  • ~version “Approximately equivalent to version”, will update you to all future patch versions, without incrementing the minor version. ~1.2.3 will use releases from 1.2.3 to <1.3.0.

  • ^version “Compatible with version”, will update you to all future minor/patch versions, without incrementing the major version. ^2.3.4 will use releases from 2.3.4 to <3.0.0.

See Comments below for exceptions, in particular for pre-one versions, such as ^0.2.3

Invalid CSRF Token 'null' was found on the request parameter '_csrf' or header 'X-CSRF-TOKEN'

Neither one of the solutions worked form me. The only one that worked for me in Spring form is:

action="./upload?${_csrf.parameterName}=${_csrf.token}"

REPLACED WITH:

action="./upload?_csrf=${_csrf.token}"

(Spring 5 with enabled csrf in java configuration)

Python reading from a file and saving to utf-8

You can't do that using open. use codecs.

when you are opening a file in python using the open built-in function you will always read/write the file in ascii. To write it in utf-8 try this:

import codecs
file = codecs.open('data.txt','w','utf-8')

What is the bower (and npm) version syntax?

You can also use the latest keyword to install the most recent version available:

  "dependencies": {
    "fontawesome": "latest"
  }

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.

What does the "~" (tilde/squiggle/twiddle) CSS selector mean?

Note that in an attribute selector (e.g., [attr~=value]), the tilde

Represents an element with an attribute name of attr whose value is a whitespace-separated list of words, one of which is exactly value.

https://developer.mozilla.org/en-US/docs/Web/CSS/Attribute_selectors

The tilde operator in Python

It is a unary operator (taking a single argument) that is borrowed from C, where all data types are just different ways of interpreting bytes. It is the "invert" or "complement" operation, in which all the bits of the input data are reversed.

In Python, for integers, the bits of the twos-complement representation of the integer are reversed (as in b <- b XOR 1 for each individual bit), and the result interpreted again as a twos-complement integer. So for integers, ~x is equivalent to (-x) - 1.

The reified form of the ~ operator is provided as operator.invert. To support this operator in your own class, give it an __invert__(self) method.

>>> import operator
>>> class Foo:
...   def __invert__(self):
...     print 'invert'
...
>>> x = Foo()
>>> operator.invert(x)
invert
>>> ~x
invert

Any class in which it is meaningful to have a "complement" or "inverse" of an instance that is also an instance of the same class is a possible candidate for the invert operator. However, operator overloading can lead to confusion if misused, so be sure that it really makes sense to do so before supplying an __invert__ method to your class. (Note that byte-strings [ex: '\xff'] do not support this operator, even though it is meaningful to invert all the bits of a byte-string.)

What is the "double tilde" (~~) operator in JavaScript?

The diffrence is very simple:

Long version

If you want to have better readability, use Math.floor. But if you want to minimize it, use tilde ~~.

There are a lot of sources on the internet saying Math.floor is faster, but sometimes ~~. I would not recommend you think about speed because it is not going to be noticed when running the code. Maybe in tests etc, but no human can see a diffrence here. What would be faster is to use ~~ for a faster load time.

Short version

~~ is shorter/takes less space. Math.floor improves the readability. Sometimes tilde is faster, sometimes Math.floor is faster, but it is not noticeable.

Excel to CSV with UTF8 encoding

I needed to automate this process on my Mac. I originally tried using catdoc/xls2csv as suggested by mpowered, but xls2csv had trouble detecting the original encoding of the document and not all documents were the same. What I ended up doing was setting the default webpage output encoding to be UTF-8 and then providing the files to Apple's Automator, applying the Convert Format of Excel Files action to convert to Web Page (HTML). Then using PHP, DOMDocument and XPath, I queried the documents and formatted them to CSV.

This is the PHP script (process.php):

<?php
$pi = pathinfo($argv[1]);
$file = $pi['dirname'] . '/' . $pi['filename'] . '.csv';
$fp = fopen($file,'w+');
$doc = new DOMDocument;
$doc->loadHTMLFile($argv[1]);
$xpath = new DOMXPath($doc);
$table = [];
foreach($xpath->query('//tr') as $row){
    $_r = [];
    foreach($xpath->query('td',$row) as $col){
        $_r[] = trim($col->textContent);
    }
    fputcsv($fp,$_r);
}
fclose($fp);
?>

And this is the shell command I used to convert the HTML documents to csv:

find . -name '*.htm' | xargs -I{} php ./process.php {}

This is a really, really roundabout way of doing this, but it was the most reliable method that I found.

What is the proper way to test if a parameter is empty in a batch file?

From IF /?:

If Command Extensions are enabled IF changes as follows:

IF [/I] string1 compare-op string2 command
IF CMDEXTVERSION number command
IF DEFINED variable command

......

The DEFINED conditional works just like EXISTS except it takes an environment variable name and returns true if the environment variable is defined.

How to check for changes on remote (origin) Git repository

I simply use

git fetch origin

to fetch the remote changes, and then I view both local and pending remote commits (and their associated changes) with the nice gitk tool involving the --all argument like:

gitk --all

Removing double quotes from variables in batch file creates problems with CMD environment

All the answers are complete. But Wanted to add one thing,

set FirstName=%~1

set LastName=%~2

This line should have worked, you needed a small change.

set "FirstName=%~1"

set "LastName=%~2"

Include the complete assignment within quotes. It will remove quotes without an issue. This is a prefered way of assignment which fixes unwanted issues with quotes in arguments.

In c++ what does a tilde "~" before a function name signify?

It's the destructor. This method is called when the instance of your class is destroyed:

Stack<int> *stack= new Stack<int>;
//do something
delete stack; //<- destructor is called here;

Meaning of tilde in Linux bash (not home directory)

Are they the home directories of users in /etc/passwd? Services like postgres, sendmail, apache, etc., create system users that have home directories just like normal users.

How does the bitwise complement operator (~ tilde) work?

~ flips the bits in the value.

Why ~2 is -3 has to do with how numbers are represented bitwise. Numbers are represented as two's complement.

So, 2 is the binary value

00000010

And ~2 flips the bits so the value is now:

11111101

Which, is the binary representation of -3.

Could someone explain this for me - for (int i = 0; i < 8; i++)

That's a loop that says, okay, for every time that i is smaller than 8, I'm going to do whatever is in the code block. Whenever i reaches 8, I'll stop. After each iteration of the loop, it increments i by 1 (i++), so that the loop will eventually stop when it meets the i < 8 (i becomes 8, so no longer is smaller than) condition.

For example, this:

for (int i = 0; i < 8; i++)
{
   Console.WriteLine(i);
}

Will output: 01234567

See how the code was executed 8 times?

In terms of arrays, this can be helpful when you don't know the size of the array, but you want to operate on every item of it. You can do:

Disclaimer: This following code will vary dependent upon language, but the principle remains the same

Array yourArray;

for (int i = 0; i < yourArray.Count; i++)
{
    Console.WriteLine(yourArray[i]);
}

The difference here is the number of execution times is entirely dependent on the size of the array, so it's dynamic.

Run PHP Task Asynchronously

PHP HAS multithreading, its just not enabled by default, there is an extension called pthreads which does exactly that. You'll need php compiled with ZTS though. (Thread Safe) Links:

Examples

Another tutorial

pthreads PECL Extension

How to overload functions in javascript?

I am using a bit different overloading approach based on arguments number. However i believe John Fawcett's approach is also good. Here the example, code based on John Resig's (jQuery's Author) explanations.

// o = existing object, n = function name, f = function.
    function overload(o, n, f){
        var old = o[n];
        o[n] = function(){
            if(f.length == arguments.length){
                return f.apply(this, arguments);
            }
            else if(typeof o == 'function'){
                return old.apply(this, arguments);
            }
        };
    }

usability:

var obj = {};
overload(obj, 'function_name', function(){ /* what we will do if no args passed? */});
overload(obj, 'function_name', function(first){ /* what we will do if 1 arg passed? */});
overload(obj, 'function_name', function(first, second){ /* what we will do if 2 args passed? */});
overload(obj, 'function_name', function(first,second,third){ /* what we will do if 3 args passed? */});
//... etc :)

How to set page content to the middle of screen?

If you want to center the content horizontally and vertically, but don't know in prior how high your page will be, you have to you use JavaScript.

HTML:

<body>
    <div id="content">...</div>
</body>

CSS:

#content {
    max-width: 1000px;
    margin: auto;
    left: 1%;
    right: 1%;
    position: absolute;
}

JavaScript (using jQuery):

$(function() {
    $(window).on('resize', function resize()  {
        $(window).off('resize', resize);
        setTimeout(function () {
            var content = $('#content');
            var top = (window.innerHeight - content.height()) / 2;
            content.css('top', Math.max(0, top) + 'px');
            $(window).on('resize', resize);
        }, 50);
    }).resize();
});

Centered horizontally and vertically

Demo: http://jsfiddle.net/nBzcb/

Attach a body onload event with JS

This takes advantage of DOMContentLoaded - which fires before onload - but allows you to stick in all your unobtrusiveness...

window.onload - Dean Edwards - The blog post talks more about it - and here is the complete code copied from the comments of that same blog.

// Dean Edwards/Matthias Miller/John Resig

function init() {
  // quit if this function has already been called
  if (arguments.callee.done) return;

  // flag this function so we don't do the same thing twice
  arguments.callee.done = true;

  // kill the timer
  if (_timer) clearInterval(_timer);

  // do stuff
};

/* for Mozilla/Opera9 */
if (document.addEventListener) {
  document.addEventListener("DOMContentLoaded", init, false);
}

/* for Internet Explorer */
/*@cc_on @*/
/*@if (@_win32)
  document.write("<script id=__ie_onload defer src=javascript:void(0)><\/script>");
  var script = document.getElementById("__ie_onload");
  script.onreadystatechange = function() {
    if (this.readyState == "complete") {
      init(); // call the onload handler
    }
  };
/*@end @*/

/* for Safari */
if (/WebKit/i.test(navigator.userAgent)) { // sniff
  var _timer = setInterval(function() {
    if (/loaded|complete/.test(document.readyState)) {
      init(); // call the onload handler
    }
  }, 10);
}

/* for other browsers */
window.onload = init;

Compress images on client side before uploading

I just developed a javascript library called JIC to solve that problem. It allows you to compress jpg and png on the client side 100% with javascript and no external libraries required!

You can try the demo here : http://makeitsolutions.com/labs/jic and get the sources here : https://github.com/brunobar79/J-I-C

How can I remove an element from a list?

Use - (Negative sign) along with position of element, example if 3rd element is to be removed use it as your_list[-3]

Input

my_list <- list(a = 3, b = 3, c = 4, d = "Hello", e = NA)
my_list
# $`a`
# [1] 3

# $b
# [1] 3

# $c
# [1] 4

# $d
# [1] "Hello"

# $e
# [1] NA

Remove single element from list

 my_list[-3]
 # $`a`
 # [1] 3

 # $b
 # [1] 3

 # $d
 # [1] "Hello"

 # $e
 [1] NA

Remove multiple elements from list

 my_list[c(-1,-3,-2)]
 # $`d`
 # [1] "Hello"

 # $e
 # [1] NA

 my_list[c(-3:-5)]
 # $`a`
 # [1] 3

 # $b
 # [1] 3

 my_list[-seq(1:2)]
 # $`c`
 # [1] 4

 # $d
 # [1] "Hello"

 # $e
 # [1] NA

Way to read first few lines for pandas dataframe

I think you can use the nrows parameter. From the docs:

nrows : int, default None

    Number of rows of file to read. Useful for reading pieces of large files

which seems to work. Using one of the standard large test files (988504479 bytes, 5344499 lines):

In [1]: import pandas as pd

In [2]: time z = pd.read_csv("P00000001-ALL.csv", nrows=20)
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00 s

In [3]: len(z)
Out[3]: 20

In [4]: time z = pd.read_csv("P00000001-ALL.csv")
CPU times: user 27.63 s, sys: 1.92 s, total: 29.55 s
Wall time: 30.23 s

How to get Enum Value from index in Java?

Here's three ways to do it.

public enum Months {
    JAN(1), FEB(2), MAR(3), APR(4), MAY(5), JUN(6), JUL(7), AUG(8), SEP(9), OCT(10), NOV(11), DEC(12);


    int monthOrdinal = 0;

    Months(int ord) {
        this.monthOrdinal = ord;
    }

    public static Months byOrdinal2ndWay(int ord) {
        return Months.values()[ord-1]; // less safe
    }

    public static Months byOrdinal(int ord) {
        for (Months m : Months.values()) {
            if (m.monthOrdinal == ord) {
                return m;
            }
        }
        return null;
    }
    public static Months[] MONTHS_INDEXED = new Months[] { null, JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC };

}




import static junit.framework.Assert.assertEquals;

import org.junit.Test;

public class MonthsTest {

@Test
public void test_indexed_access() {
    assertEquals(Months.MONTHS_INDEXED[1], Months.JAN);
    assertEquals(Months.MONTHS_INDEXED[2], Months.FEB);

    assertEquals(Months.byOrdinal(1), Months.JAN);
    assertEquals(Months.byOrdinal(2), Months.FEB);


    assertEquals(Months.byOrdinal2ndWay(1), Months.JAN);
    assertEquals(Months.byOrdinal2ndWay(2), Months.FEB);
}

}

Android- Error:Execution failed for task ':app:transformClassesWithDexForRelease'

None of these answers worked for me. I am using Android studio 3.4.1.

I was able to build the project but Android studio showing this error when I was going to deploy it to mobile device. It turns out it is "instant runs" fault.

Follow this answer: https://stackoverflow.com/a/42695197/3197467

What does enumerate() mean?

It's a builtin function that returns an object that can be iterated over. See the documentation.

In short, it loops over the elements of an iterable (like a list), as well as an index number, combined in a tuple:

for item in enumerate(["a", "b", "c"]):
    print item

prints

(0, "a")
(1, "b")
(2, "c")

It's helpful if you want to loop over a sequence (or other iterable thing), and also want to have an index counter available. If you want the counter to start from some other value (usually 1), you can give that as second argument to enumerate.

horizontal line and right way to code it in html, css

If you really want a thematic break, by all means use the <hr> tag.


If you just want a design line, you could use something like the css class

.hline-bottom {
    padding-bottom: 10px;
    border-bottom: 2px solid #000; /* whichever color you prefer */
}

and use it like

<div class="block_1 hline-bottom">Cheese</div>

Printing a 2D array in C

Is this any help?

#include <stdio.h>

#define MAX 10

int main()
{
    char grid[MAX][MAX];
    int i,j,row,col;

    printf("Please enter your grid size: ");
    scanf("%d %d", &row, &col);


    for (i = 0; i < row; i++) {
        for (j = 0; j < col; j++) {
            grid[i][j] = '.';
            printf("%c ", grid[i][j]);
        }
        printf("\n");
    }

    return 0;
}

what do <form action="#"> and <form method="post" action="#"> do?

The # tag lets you send your data to the same file. I see it as a three step process:

  1. Query a DB to populate a from
  2. Allow the user to change data in the form
  3. Resubmit the data to the DB via the php script

With the method='#' you can do all of this in the same file.

After the submit query is executed the page will reload with the updated data from the DB.

Wait for a process to finish

Had the same issue, I solved the issue killing the process and then waiting for each process to finish using the PROC filesystem:

while [ -e /proc/${pid} ]; do sleep 0.1; done

Laravel Carbon subtract days from current date

Use subDays() method:

$users = Users::where('status_id', 'active')
           ->where( 'created_at', '>', Carbon::now()->subDays(30))
           ->get();

Node update a specific package

Use npm outdated to see Current and Latest version of all packages.


Then npm i packageName@versionNumber to install specific version : example npm i [email protected].

Or npm i packageName@latest to install latest version : example npm i browser-sync@latest.

How can I get all a form's values that would be submitted without submitting

The jquery form plugin offers an easy way to iterate over your form elements and put them in a query string. It might also be useful for whatever else you need to do with these values.

var queryString = $('#myFormId').formSerialize();

From http://malsup.com/jquery/form

Or using straight jquery:

var queryString = $('#myFormId').serialize();

Linq to SQL how to do "where [column] in (list of values)"

I had been using the method in Jon Skeet's answer, but another one occurred to me using Concat. The Concat method performed slightly better in a limited test, but it's a hassle and I'll probably just stick with Contains, or maybe I'll write a helper method to do this for me. Either way, here's another option if anyone is interested:

The Method

// Given an array of id's
var ids = new Guid[] { ... };

// and a DataContext
var dc = new MyDataContext();

// start the queryable
var query = (
    from thing in dc.Things
    where thing.Id == ids[ 0 ]
    select thing 
);

// then, for each other id
for( var i = 1; i < ids.Count(); i++ ) {
    // select that thing and concat to queryable
    query.Concat(
        from thing in dc.Things
        where thing.Id == ids[ i ]
        select thing
    );
}

Performance Test

This was not remotely scientific. I imagine your database structure and the number of IDs involved in the list would have a significant impact.

I set up a test where I did 100 trials each of Concat and Contains where each trial involved selecting 25 rows specified by a randomized list of primary keys. I've run this about a dozen times, and most times the Concat method comes out 5 - 10% faster, although one time the Contains method won by just a smidgen.

git: How to diff changed files versus previous versions after a pull?

If you do a straight git pull then you will either be 'fast-forwarded' or merge an unknown number of commits from the remote repository. This happens as one action though, so the last commit that you were at immediately before the pull will be the last entry in the reflog and can be accessed as HEAD@{1}. This means that you can do:

git diff HEAD@{1}

However, I would strongly recommend that if this is something you find yourself doing a lot then you should consider just doing a git fetch and examining the fetched branch before manually merging or rebasing onto it. E.g. if you're on master and were going to pull in origin/master:

git fetch

git log HEAD..origin/master

 # looks good, lets merge

git merge origin/master

Using psql to connect to PostgreSQL in SSL mode

On psql client v12, I could not find option in psql client to activate sslmode=verify-full.

I ended up using environment variables :

PGSSLMODE=verify-full PGSSLROOTCERT=server-ca.pem psql -h your_host -U your_user -W -d your_db

Get line number while using grep

If you want only the line number do this:

grep -n Pattern file.ext | gawk '{print $1}' FS=":"

Example:

$ grep -n 9780545460262 EXT20130410.txt | gawk '{print $1}' FS=":" 
48793
52285
54023

Calculating powers of integers

Guava's math libraries offer two methods that are useful when calculating exact integer powers:

pow(int b, int k) calculates b to the kth the power, and wraps on overflow

checkedPow(int b, int k) is identical except that it throws ArithmeticException on overflow

Personally checkedPow() meets most of my needs for integer exponentiation and is cleaner and safter than using the double versions and rounding, etc. In almost all the places I want a power function, overflow is an error (or impossible, but I want to be told if the impossible ever becomes possible).

If you want get a long result, you can just use the corresponding LongMath methods and pass int arguments.

Create Generic method constraining T to an Enum

Just for completeness, the following is a Java solution. I am certain the same could be done in C# as well. It avoids having to specify the type anywhere in code - instead, you specify it in the strings you are trying to parse.

The problem is that there isn't any way to know which enumeration the String might match - so the answer is to solve that problem.

Instead of accepting just the string value, accept a String that has both the enumeration and the value in the form "enumeration.value". Working code is below - requires Java 1.8 or later. This would also make the XML more precise as in you would see something like color="Color.red" instead of just color="red".

You would call the acceptEnumeratedValue() method with a string containing the enum name dot value name.

The method returns the formal enumerated value.

import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;


public class EnumFromString {

    enum NumberEnum {One, Two, Three};
    enum LetterEnum {A, B, C};


    Map<String, Function<String, ? extends Enum>> enumsByName = new HashMap<>();

    public static void main(String[] args) {
        EnumFromString efs = new EnumFromString();

        System.out.print("\nFirst string is NumberEnum.Two - enum is " + efs.acceptEnumeratedValue("NumberEnum.Two").name());
        System.out.print("\nSecond string is LetterEnum.B - enum is " + efs.acceptEnumeratedValue("LetterEnum.B").name());

    }

    public EnumFromString() {
        enumsByName.put("NumberEnum", s -> {return NumberEnum.valueOf(s);});
        enumsByName.put("LetterEnum", s -> {return LetterEnum.valueOf(s);});
    }

    public Enum acceptEnumeratedValue(String enumDotValue) {

        int pos = enumDotValue.indexOf(".");

        String enumName = enumDotValue.substring(0, pos);
        String value = enumDotValue.substring(pos + 1);

        Enum enumeratedValue = enumsByName.get(enumName).apply(value);

        return enumeratedValue;
    }


}

How to auto resize and adjust Form controls with change in resolution

this.WindowState = FormWindowState.Maximized;

MVVM Passing EventArgs As Command Parameter

I try to keep my dependencies to a minimum, so I implemented this myself instead of going with EventToCommand of MVVMLight. Works for me so far, but feedback is welcome.

Xaml:

<i:Interaction.Behaviors>
    <beh:EventToCommandBehavior Command="{Binding DropCommand}" Event="Drop" PassArguments="True" />
</i:Interaction.Behaviors>

ViewModel:

public ActionCommand<DragEventArgs> DropCommand { get; private set; }

this.DropCommand = new ActionCommand<DragEventArgs>(OnDrop);

private void OnDrop(DragEventArgs e)
{
    // ...
}

EventToCommandBehavior:

/// <summary>
/// Behavior that will connect an UI event to a viewmodel Command,
/// allowing the event arguments to be passed as the CommandParameter.
/// </summary>
public class EventToCommandBehavior : Behavior<FrameworkElement>
{
    private Delegate _handler;
    private EventInfo _oldEvent;

    // Event
    public string Event { get { return (string)GetValue(EventProperty); } set { SetValue(EventProperty, value); } }
    public static readonly DependencyProperty EventProperty = DependencyProperty.Register("Event", typeof(string), typeof(EventToCommandBehavior), new PropertyMetadata(null, OnEventChanged));

    // Command
    public ICommand Command { get { return (ICommand)GetValue(CommandProperty); } set { SetValue(CommandProperty, value); } }
    public static readonly DependencyProperty CommandProperty = DependencyProperty.Register("Command", typeof(ICommand), typeof(EventToCommandBehavior), new PropertyMetadata(null));

    // PassArguments (default: false)
    public bool PassArguments { get { return (bool)GetValue(PassArgumentsProperty); } set { SetValue(PassArgumentsProperty, value); } }
    public static readonly DependencyProperty PassArgumentsProperty = DependencyProperty.Register("PassArguments", typeof(bool), typeof(EventToCommandBehavior), new PropertyMetadata(false));


    private static void OnEventChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var beh = (EventToCommandBehavior)d;

        if (beh.AssociatedObject != null) // is not yet attached at initial load
            beh.AttachHandler((string)e.NewValue);
    }

    protected override void OnAttached()
    {
        AttachHandler(this.Event); // initial set
    }

    /// <summary>
    /// Attaches the handler to the event
    /// </summary>
    private void AttachHandler(string eventName)
    {
        // detach old event
        if (_oldEvent != null)
            _oldEvent.RemoveEventHandler(this.AssociatedObject, _handler);

        // attach new event
        if (!string.IsNullOrEmpty(eventName))
        {
            EventInfo ei = this.AssociatedObject.GetType().GetEvent(eventName);
            if (ei != null)
            {
                MethodInfo mi = this.GetType().GetMethod("ExecuteCommand", BindingFlags.Instance | BindingFlags.NonPublic);
                _handler = Delegate.CreateDelegate(ei.EventHandlerType, this, mi);
                ei.AddEventHandler(this.AssociatedObject, _handler);
                _oldEvent = ei; // store to detach in case the Event property changes
            }
            else
                throw new ArgumentException(string.Format("The event '{0}' was not found on type '{1}'", eventName, this.AssociatedObject.GetType().Name));
        }
    }

    /// <summary>
    /// Executes the Command
    /// </summary>
    private void ExecuteCommand(object sender, EventArgs e)
    {
        object parameter = this.PassArguments ? e : null;
        if (this.Command != null)
        {
            if (this.Command.CanExecute(parameter))
                this.Command.Execute(parameter);
        }
    }
}

ActionCommand:

public class ActionCommand<T> : ICommand
{
    public event EventHandler CanExecuteChanged;
    private Action<T> _action;

    public ActionCommand(Action<T> action)
    {
        _action = action;
    }

    public bool CanExecute(object parameter) { return true; }

    public void Execute(object parameter)
    {
        if (_action != null)
        {
            var castParameter = (T)Convert.ChangeType(parameter, typeof(T));
            _action(castParameter);
        }
    }
}

Why is the GETDATE() an invalid identifier

SYSDATE and GETDATE perform identically.

SYSDATE is compatible with Oracle syntax, and GETDATE is compatible with Microsoft SQL Server syntax.

How to use foreach with a hash reference?

As others have stated, you have to dereference the reference. The keys function requires that its argument starts with a %:

My preference:

foreach my $key (keys %{$ad_grp_ref}) {

According to Conway:

foreach my $key (keys %{ $ad_grp_ref }) {

Guess who you should listen to...

You might want to read through the Perl Reference Documentation.

If you find yourself doing a lot of stuff with references to hashes and hashes of lists and lists of hashes, you might want to start thinking about using Object Oriented Perl. There's a lot of nice little tutorials in the Perl documentation.

When to use Comparable and Comparator

Comparator does everything that comparable does, plus more.

| | Comparable | Comparator ._______________________________________________________________________________ Is used to allow Collections.sort to work | yes | yes Can compare multiple fields | yes | yes Lives inside the class you’re comparing and serves | | as a “default” way to compare | yes | yes Can live outside the class you’re comparing | no | yes Can have multiple instances with different method names | no | yes Input arguments can be a list of | just Object| Any type Can use enums | no | yes

I found the best approach to use comparators as anonymous classes as follows:

private static void sortAccountsByPriority(List<AccountRecord> accounts) {
    Collections.sort(accounts, new Comparator<AccountRecord>() {

        @Override
        public int compare(AccountRecord a1, AccountRecord a2) {
            return a1.getRank().compareTo(a2.getRank());
        }
    });
}

You can create multiple versions of such methods right inside the class you’re planning to sort. So you can have:

  • sortAccountsByPriority
  • sortAccountsByType
  • sortAccountsByPriorityAndType

    etc...

Now, you can use these sort methods anywhere and get code reuse. This gives me everything a comparable would, plus more ... so I don’t see any reason to use comparable at all.

How do I parse an ISO 8601-formatted date?

Thanks to great Mark Amery's answer I devised function to account for all possible ISO formats of datetime:

class FixedOffset(tzinfo):
    """Fixed offset in minutes: `time = utc_time + utc_offset`."""
    def __init__(self, offset):
        self.__offset = timedelta(minutes=offset)
        hours, minutes = divmod(offset, 60)
        #NOTE: the last part is to remind about deprecated POSIX GMT+h timezones
        #  that have the opposite sign in the name;
        #  the corresponding numeric value is not used e.g., no minutes
        self.__name = '<%+03d%02d>%+d' % (hours, minutes, -hours)
    def utcoffset(self, dt=None):
        return self.__offset
    def tzname(self, dt=None):
        return self.__name
    def dst(self, dt=None):
        return timedelta(0)
    def __repr__(self):
        return 'FixedOffset(%d)' % (self.utcoffset().total_seconds() / 60)
    def __getinitargs__(self):
        return (self.__offset.total_seconds()/60,)

def parse_isoformat_datetime(isodatetime):
    try:
        return datetime.strptime(isodatetime, '%Y-%m-%dT%H:%M:%S.%f')
    except ValueError:
        pass
    try:
        return datetime.strptime(isodatetime, '%Y-%m-%dT%H:%M:%S')
    except ValueError:
        pass
    pat = r'(.*?[+-]\d{2}):(\d{2})'
    temp = re.sub(pat, r'\1\2', isodatetime)
    naive_date_str = temp[:-5]
    offset_str = temp[-5:]
    naive_dt = datetime.strptime(naive_date_str, '%Y-%m-%dT%H:%M:%S.%f')
    offset = int(offset_str[-4:-2])*60 + int(offset_str[-2:])
    if offset_str[0] == "-":
        offset = -offset
    return naive_dt.replace(tzinfo=FixedOffset(offset))

Back to previous page with header( "Location: " ); in PHP

Storing previous url in a session variable is bad, because the user might right click on multiple pages and then come back and save.

unless you save the previous url in the session variable to a hidden field in the form and after save header( "Location: save URL of calling page" );

How to add a new column to a CSV file?

This should give you an idea of what to do:

>>> v = open('C:/test/test.csv')
>>> r = csv.reader(v)
>>> row0 = r.next()
>>> row0.append('berry')
>>> print row0
['Name', 'Code', 'berry']
>>> for item in r:
...     item.append(item[0])
...     print item
...     
['blackberry', '1', 'blackberry']
['wineberry', '2', 'wineberry']
['rasberry', '1', 'rasberry']
['blueberry', '1', 'blueberry']
['mulberry', '2', 'mulberry']
>>> 

Edit, note in py3k you must use next(r)

Thanks for accepting the answer. Here you have a bonus (your working script):

import csv

with open('C:/test/test.csv','r') as csvinput:
    with open('C:/test/output.csv', 'w') as csvoutput:
        writer = csv.writer(csvoutput, lineterminator='\n')
        reader = csv.reader(csvinput)

        all = []
        row = next(reader)
        row.append('Berry')
        all.append(row)

        for row in reader:
            row.append(row[0])
            all.append(row)

        writer.writerows(all)

Please note

  1. the lineterminator parameter in csv.writer. By default it is set to '\r\n' and this is why you have double spacing.
  2. the use of a list to append all the lines and to write them in one shot with writerows. If your file is very, very big this probably is not a good idea (RAM) but for normal files I think it is faster because there is less I/O.
  3. As indicated in the comments to this post, note that instead of nesting the two with statements, you can do it in the same line:

    with open('C:/test/test.csv','r') as csvinput, open('C:/test/output.csv', 'w') as csvoutput:

How does one convert a grayscale image to RGB in OpenCV (Python)?

One you convert your image to gray-scale you cannot got back. You have gone from three channel to one, when you try to go back all three numbers will be the same. So the short answer is no you cannot go back. The reason your backtorgb function this throwing that error is because it needs to be in the format:

CvtColor(input, output, CV_GRAY2BGR)

OpenCV use BGR not RGB, so if you fix the ordering it should work, though your image will still be gray.

jQuery-UI datepicker default date

jQuery UI Datepicker is coded to always highlight the user's local date using the class ui-state-highlight. There is no built-in option to change this.

One method, described similarly in other answers to related questions, is to override the CSS for that class to match ui-state-default of your theme, for example:

.ui-state-highlight {
    border: 1px solid #d3d3d3;
    background: #e6e6e6 url(images/ui-bg_glass_75_e6e6e6_1x400.png) 50% 50% repeat-x;
    color: #555555;
}

However this isn't very helpful if you are using dynamic themes, or if your intent is to highlight a different day (e.g., to have "today" be based on your server's clock rather than the client's).

An alternative approach is to override the datepicker prototype that is responsible for highlighting the current day.

Assuming that you are using a minimized version of the UI javascript, the following snippets can address these concerns.


If your goal is to prevent highlighting the current day altogether:

// copy existing _generateHTML method
var _generateHTML = jQuery.datepicker.constructor.prototype._generateHTML;
// remove the string "ui-state-highlight"
_generateHtml.toString().replace(' ui-state-highlight', '');
// and replace the prototype method
eval('jQuery.datepicker.constructor.prototype._generateHTML = ' + _generateHTML);

This changes the relevant code (unminimized for readability) from:

[...](printDate.getTime() == today.getTime() ? ' ui-state-highlight' : '') + [...]

to

[...](printDate.getTime() == today.getTime() ? '' : '') + [...]

If your goal is to change datepicker's definition of "today":

var useMyDateNotYours = '07/28/2014';
// copy existing _generateHTML method
var _generateHTML = jQuery.datepicker.constructor.prototype._generateHTML;
// set "today" to your own Date()-compatible date
_generateHTML.toString().replace('new Date,', 'new Date(useMyDateNotYours),');
// and replace the prototype method
eval('jQuery.datepicker.constructor.prototype._generateHTML = ' + _generateHTML);

This changes the relevant code (unminimized for readability) from:

[...]var today = new Date();[...]

to

[...]var today = new Date(useMyDateNotYours);[...]
// Note that in the minimized version, the line above take the form `L=new Date,`
// (part of a list of variable declarations, and Date is instantiated without parenthesis)

Instead of useMyDateNotYours you could of course also instead inject a string, function, or whatever suits your needs.

PHP GuzzleHttp. How to make a post request with params?

Note in Guzzle V6.0+, another source of getting the following error may be incorrect use of JSON as an array:

Passing in the "body" request option as an array to send a POST request has been deprecated. Please use the "form_params" request option to send a application/x-www-form-urlencoded request, or a the "multipart" request option to send a multipart/form-data request.

Incorrect:

$response = $client->post('http://example.com/api', [
    'body' => [
        'name' => 'Example name',
    ]
])

Correct:

$response = $client->post('http://example.com/api', [
    'json' => [
        'name' => 'Example name',
    ]
])

Correct:

$response = $client->post('http://example.com/api', [
    'headers' => ['Content-Type' => 'application/json'],
    'body' => json_encode([
        'name' => 'Example name',
    ])
])

Simplest Way to Test ODBC on WIndows

One way to create a quick test query in Windows via an ODBC connection is using the DQY format.

To achieve this, create a DQY file (e.g. test.dqy) containing the magic first two lines (XLODBC and 1) as below, followed by your ODBC connection string on the third line and your query on the fourth line (all on one line), e.g.:

XLODBC
1
Driver={Microsoft ODBC for Oracle};server=DB;uid=scott;pwd=tiger;
SELECT COUNT(1) n FROM emp

Then, if you open the file by double-clicking it, it will open in Excel and populate the worksheet with the results of the query.

Can't start hostednetwork

If none of the above answers worked for you, You can try the following solution which worked for me.

Go to Services manager(services.msc) and enable the below services and try again.
  1. WLAN AutoConfig
  2. Wi-Fi Direct Services Connection Manager Service

Hope this solved your problem.

Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize

I got similar message when running command line mvn (version 3.3.3) on Linux with Java 8. By opening maven script /$MAVEN-HOME/bin/mvn, found the following line

MAVEN_OPTS="$(concat_lines "$MAVEN_PROJECTBASEDIR/.mvn/jvm.config") $MAVEN_OPTS"

Where $MAVEN_PROJECTBASEDIR by default is your home directory. So two places you can take a look, first is file $MAVEN_PROJECTBASEDIR/.mvn/jvm.config if it exists. Secondly look at files possibly set up the environment variable MAVEN_OPTS. Candidate files are .bashrc, .bash_profile, .profile and those files included by them such as /etc/profile, /etc/bash.bashrc

I located

export MAVEN_OPTS="-Xmx512m -XX:MaxPermSize=256m"

in .bashrc in my system, change it to

export MAVEN_OPTS="-Xmx512m"

issue resolved

GnuPG: "decryption failed: secret key not available" error from gpg on Windows

Yes, your secret key appears to be missing. Without it, you will not be able to decrypt the files.

Do you have the key backed up somewhere?

Re-creating the keys, whether you use the same passphrase or not, will not work. Each key pair is unique.

Using Linq to get the last N elements of a collection?

//detailed code for the problem
//suppose we have a enumerable collection 'collection'
var lastIndexOfCollection=collection.Count-1 ;
var nthIndexFromLast= lastIndexOfCollection- N;

var desiredCollection=collection.GetRange(nthIndexFromLast, N);
---------------------------------------------------------------------

// use this one liner
var desiredCollection=collection.GetRange((collection.Count-(1+N)), N);

The best way to calculate the height in a binary search tree? (balancing an AVL-tree)

You do not need to calculate tree depths on the fly.

You can maintain them as you perform operations.

Furthermore, you don't actually in fact have to maintain track of depths; you can simply keep track of the difference between the left and right tree depths.

http://www.eternallyconfuzzled.com/tuts/datastructures/jsw_tut_avl.aspx

Just keeping track of the balance factor (difference between left and right subtrees) is I found easier from a programming POV, except that sorting out the balance factor after a rotation is a PITA...

MySQL DAYOFWEEK() - my week begins with monday

Try to use the WEEKDAY() function.

Returns the weekday index for date (0 = Monday, 1 = Tuesday, … 6 = Sunday).

Reading Email using Pop3 in C#

You can also try Mail.dll mail component, it has SSL support, unicode, and multi-national email support:

using(Pop3 pop3 = new Pop3())
{
    pop3.Connect("mail.host.com");           // Connect to server and login
    pop3.Login("user", "password");

    foreach(string uid in pop3.GetAll())
    {
        IMail email = new MailBuilder()
            .CreateFromEml(pop3.GetMessageByUID(uid));
          Console.WriteLine( email.Subject );
    }
    pop3.Close(false);      
}

You can download it here at https://www.limilabs.com/mail

Please note that this is a commercial product I've created.

How do I go about adding an image into a java project with eclipse?

It is very simple to adding an image into project and view the image. First create a folder into in your project which can contain any type of images.

Then Right click on Project ->>Go to Build Path ->> configure Build Path ->> add Class folder ->> choose your folder (which you just created for store the images) under the project name.

class Surface extends JPanel {

    private BufferedImage slate;
    private BufferedImage java;
    private BufferedImage pane;
    private TexturePaint slatetp;
    private TexturePaint javatp;
    private TexturePaint panetp;

    public Surface() {

        loadImages();
    }

    private void loadImages() {

        try {

            slate = ImageIO.read(new File("images\\slate.png"));
            java = ImageIO.read(new File("images\\java.png"));
            pane = ImageIO.read(new File("images\\pane.png"));

        } catch (IOException ex) {

            Logger.`enter code here`getLogger(Surface.class.getName()).log(
                    Level.SEVERE, null, ex);
        }
    }

    private void doDrawing(Graphics g) {

        Graphics2D g2d = (Graphics2D) g.create();

        slatetp = new TexturePaint(slate, new Rectangle(0, 0, 90, 60));
        javatp = new TexturePaint(java, new Rectangle(0, 0, 90, 60));
        panetp = new TexturePaint(pane, new Rectangle(0, 0, 90, 60));

        g2d.setPaint(slatetp);
        g2d.fillRect(10, 15, 90, 60);

        g2d.setPaint(javatp);
        g2d.fillRect(130, 15, 90, 60);

        g2d.setPaint(panetp);
        g2d.fillRect(250, 15, 90, 60);

        g2d.dispose();
    }

    @Override
    public void paintComponent(Graphics g) {

        super.paintComponent(g);
        doDrawing(g);
    }
}

public class TexturesEx extends JFrame {

    public TexturesEx() {

        initUI();
    }

    private void initUI() {

        add(new Surface());

        setTitle("Textures");
        setSize(360, 120);
        setLocationRelativeTo(null);        
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                TexturesEx ex = new TexturesEx();
                ex.setVisible(true);
            }
        });
    }
}

How to use conditional statement within child attribute of a Flutter Widget (Center Widget)

I found out that an easy way to use conditional logic to build Flutter UI is to keep the logic outside of the UI. Here is a function to return two different colors:

Color getColor(int selector) {
  if (selector % 2 == 0) {
    return Colors.blue;
  } else {
    return Colors.blueGrey;
  }
}

The function is used below to to set the background of the CircleAvatar.

new ListView.builder(
  itemCount: users.length,
  itemBuilder: (BuildContext context, int index) {
    return new Column(
      children: <Widget>[
        new ListTile(
          leading: new CircleAvatar(
            backgroundColor: getColor(index),
            child: new Text(users[index].name[0])
          ),
          title: new Text(users[index].login),
          subtitle: new Text(users[index].name),
        ),
        new Divider(height: 2.0),
      ],
    );
  },
);

Very neat as you can reuse your color selector function in several widgets.

Getting android.content.res.Resources$NotFoundException: exception even when the resource is present in android

This can happen due to a different language in the phone for which your code doesn't have the asset for. For example your preference.xml is placed in xml-en and you are trying to run your app in a phone which has French selected, the app will crash.

Change tab bar item selected color in a storyboard

Add Runtime Color attribute named "tintColor" from StoryBoard. This is working(for Xcode 8 and above).

if you want unselected color.. you can add unselectedItemTintColor too.

setting tintColor as Runtime Attribute

UnicodeDecodeError: 'ascii' codec can't decode byte 0xef in position 1

My +1 to mata's comment at https://stackoverflow.com/a/10561979/1346705 and to the Nick Craig-Wood's demonstration. You have decoded the string correctly. The problem is with the print command as it converts the Unicode string to the console encoding, and the console is not capable to display the string. Try to write the string into a file and look at the result using some decent editor that supports Unicode:

import codecs

s = '(\xef\xbd\xa1\xef\xbd\xa5\xcf\x89\xef\xbd\xa5\xef\xbd\xa1)\xef\xbe\x89'
s1 = s.decode('utf-8')
f = codecs.open('out.txt', 'w', encoding='utf-8')
f.write(s1)
f.close()

Then you will see (?????)?.

Android get image path from drawable as string

I think you cannot get it as String but you can get it as int by get resource id:

int resId = this.getResources().getIdentifier("imageNameHere", "drawable", this.getPackageName());

Why is using onClick() in HTML a bad practice?

With very large JavaScript applications, programmers are using more encapsulation of code to avoid polluting the global scope. And to make a function available to the onClick action in an HTML element, it has to be in the global scope.

You may have seen JS files that look like this...

(function(){
    ...[some code]
}());

These are Immediately Invoked Function Expressions (IIFEs) and any function declared within them will only exist within their internal scope.

If you declare function doSomething(){} within an IIFE, then make doSomething() an element's onClick action in your HTML page, you'll get an error.

If, on the other hand, you create an eventListener for that element within that IIFE and call doSomething() when the listener detects a click event, you're good because the listener and doSomething() share the IIFE's scope.

For little web apps with a minimal amount of code, it doesn't matter. But if you aspire to write large, maintainable codebases, onclick="" is a habit that you should work to avoid.

How to read an http input stream

try this code

String data = "";
InputStream iStream = httpEntity.getContent();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream, "utf8"));
StringBuffer sb = new StringBuffer();
String line = "";

while ((line = br.readLine()) != null) {
    sb.append(line);
}

data = sb.toString();
System.out.println(data);

How to fix "Root element is missing." when doing a Visual Studio (VS) Build?

Deleting the .user file is exactly what fixed the problem for me. Lightning strike near the office shut my PC down and corrupted my .user file and project wouldn't load. I opened the file in Notepad++ and the "spaces" turned out to be [NULL] characters. Deleted the .user file and the file loaded!

source https://forums.asp.net/t/1491251.aspx?Can+t+load+project+because+root+element+is+missing+

Reference to non-static member function must be called

The problem is that buttonClickedEvent is a member function and you need a pointer to member in order to invoke it.

Try this:

void (MyClass::*func)(int);
func = &MyClass::buttonClickedEvent;

And then when you invoke it, you need an object of type MyClass to do so, for example this:

(this->*func)(<argument>);

http://www.codeguru.com/cpp/cpp/article.php/c17401/C-Tutorial-PointertoMember-Function.htm

Code line wrapping - how to handle long lines

In general, I break lines before operators, and indent the subsequent lines:

Map<long parameterization> longMap
    = new HashMap<ditto>();

String longString = "some long text"
                  + " some more long text";

To me, the leading operator clearly conveys that "this line was continued from something else, it doesn't stand on its own." Other people, of course, have different preferences.

css to make bootstrap navbar transparent

_x000D_
_x000D_
<nav class="navbar navbar-expand-lg navbar-light fixed-top bg-transparent">
              <a class="navbar-brand" href="#">Navbar w/ text</a>
              <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarText" aria-controls="navbarText" aria-expanded="false" aria-label="Toggle navigation">
                <span class="navbar-toggler-icon"></span>
              </button>
              <div class="collapse navbar-collapse" id="navbarText">
                <ul class="navbar-nav mr-auto">
                  <li class="nav-item active">
                    <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
                  </li>
                  <li class="nav-item">
                    <a class="nav-link" href="#">Features</a>
                  </li>
                  <li class="nav-item">
                    <a class="nav-link" href="#">Pricing</a>
                  </li>
                </ul>
                <span class="navbar-text">
                  Navbar text with an inline element
                </span>
              </div>
            </nav>
_x000D_
_x000D_
_x000D_

How to use Scanner to accept only valid int as input

  1. the condition num2 < num1 should be num2 <= num1 if num2 has to be greater than num1
  2. not knowing what the kb object is, I'd read a String and then trying Integer.parseInt() and if you don't catch an exception then it's a number, if you do, read a new one, maybe by setting num2 to Integer.MIN_VALUE and using the same type of logic in your example.

How to store Query Result in variable using mysql

Additionally, if you want to set multiple variables at once by one query, you can use the other syntax for setting variables which goes like this: SELECT @varname:=value.

A practical example:

SELECT @total_count:=COUNT(*), @total_price:=SUM(quantity*price) FROM items ...

How do I set/unset a cookie with jQuery?

Here is how you set the cookie with JavaScript:

below code has been taken from https://www.w3schools.com/js/js_cookies.asp

function setCookie(cname, cvalue, exdays) {
    var d = new Date();
    d.setTime(d.getTime() + (exdays*24*60*60*1000));
    var expires = "expires="+ d.toUTCString();
    document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}

now you can get the cookie with below function:

function getCookie(cname) {
    var name = cname + "=";
    var decodedCookie = decodeURIComponent(document.cookie);
    var ca = decodedCookie.split(';');
    for(var i = 0; i <ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') {
            c = c.substring(1);
        }
        if (c.indexOf(name) == 0) {
            return c.substring(name.length, c.length);
        }
    }
    return "";
}

And finally this is how you check the cookie:

function checkCookie() {
    var username = getCookie("username");
    if (username != "") {
        alert("Welcome again " + username);
    } else {
        username = prompt("Please enter your name:", "");
        if (username != "" && username != null) {
            setCookie("username", username, 365);
        }
    }
}

If you want to delete the cookie just set the expires parameter to a passed date:

document.cookie = "username=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/;";

How can I prevent the textarea from stretching beyond his parent DIV element? (google-chrome issue only)

To disable resizing completely:

textarea {
    resize: none;
}

To allow only vertical resizing:

textarea {
    resize: vertical;
}

To allow only horizontal resizing:

textarea {
    resize: horizontal;
}

Or you can limit size:

textarea {
    max-width: 100px; 
    max-height: 100px;
}

To limit size to parents width and/or height:

textarea {
    max-width: 100%; 
    max-height: 100%;
}

How to resolve TypeError: can only concatenate str (not "int") to str

Problem is you are doing the following

str(chr(char + 7429146))

where char is a string. You cannot add a int with a string. this will cause that error

maybe if you want to get the ascii code and add it with a constant number. if so , you can just do ord(char) and add it to a number. but again, chr can take values between 0 and 1114112

Bootstrap 3 Horizontal Divider (not in a dropdown)

Currently it only works for the .dropdown-menu:

.dropdown-menu .divider {
  height: 1px;
  margin: 9px 0;
  overflow: hidden;
  background-color: #e5e5e5;
}

If you want it for other use, in your own css, following the bootstrap.css create another one:

.divider {
  height: 1px;
  width:100%;
  display:block; /* for use on default inline elements like span */
  margin: 9px 0;
  overflow: hidden;
  background-color: #e5e5e5;
}

Declaring variables in Excel Cells

I also just found out how to do this with the Excel Name Manager (Formulas > Defined Names Section > Name Manager).

You can define a variable that doesn't have to "live" within a cell and then you can use it in formulas.

Excel Name Manager

How to Select Min and Max date values in Linq Query

dim mydate = from cv in mydata.t1s
  select cv.date1 asc

datetime mindata = mydate[0];

IF statement: how to leave cell blank if condition is false ("" does not work)

This shall work (modification on above, workaround, not formula)

Modify your original formula: =IF(A1=1,B1,"filler")

Put filter on spreadsheet, choose only "filler" in column B, highlight all the cells with "filler" in them, hit delete, remove filter

500 internal server error at GetResponse()

For me this error occurred because I had 2 web API actions that had the exact same signatures and both had the same verbs, HttpPost, what I did was change one of the verbs (the one used for updating) to PUT and the error was removed. The following in my catch statement helped in getting to the root of the problem:

catch (WebException webex)
{
                WebResponse errResp = webex.Response;
                using (Stream respStream = errResp.GetResponseStream())
                {
                    StreamReader reader = new StreamReader(respStream);
                    string text = reader.ReadToEnd();
                }
}

How do I select the "last child" with a specific class name in CSS?

This is a cheeky answer, but if you are constrained to CSS only and able to reverse your items in the DOM, it might be worth considering. It relies on the fact that while there is no selector for the last element of a specific class, it is actually possible to style the first. The trick is to then use flexbox to display the elements in reverse order.

_x000D_
_x000D_
ul {_x000D_
  display: flex;_x000D_
  flex-direction: column-reverse;_x000D_
}_x000D_
_x000D_
/* Apply desired style to all matching elements. */_x000D_
ul > li.list {_x000D_
  background-color: #888;_x000D_
}_x000D_
_x000D_
/* Using a more specific selector, "unstyle" elements which are not the first. */_x000D_
ul > li.list ~ li.list {_x000D_
  background-color: inherit;_x000D_
}
_x000D_
<ul>_x000D_
  <li class="list">0</li>_x000D_
  <li>1</li>_x000D_
  <li class="list">2</li>_x000D_
</ul>_x000D_
<ul>_x000D_
  <li>0</li>_x000D_
  <li class="list">1</li>_x000D_
  <li class="list">2</li>_x000D_
  <li>3</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

What does LPCWSTR stand for and how should it be handled with?

It's a long pointer to a constant, wide string (i.e. a string of wide characters).

Since it's a wide string, you want to make your constant look like: L"TestWindow". I wouldn't create the intermediate a either, I'd just pass L"TestWindow" for the parameter:

ghTest = FindWindowEx(NULL, NULL, NULL, L"TestWindow");

If you want to be pedantically correct, an "LPCTSTR" is a "text" string -- a wide string in a Unicode build and a narrow string in an ANSI build, so you should use the appropriate macro:

ghTest = FindWindow(NULL, NULL, NULL, _T("TestWindow"));

Few people care about producing code that can compile for both Unicode and ANSI character sets though, and if you don't getting it to really work correctly can be quite a bit of extra work for little gain. In this particular case, there's not much extra work, but if you're manipulating strings, there's a whole set of string manipulation macros that resolve to the correct functions.

Git commit -a "untracked files"?

As the name suggests 'untracked files' are the files which are not being tracked by git. They are not in your staging area, and were not part of any previous commits. If you want them to be versioned (or to be managed by git) you can do so by telling 'git' by using 'git add'. Check this chapter Recording Changes to the Repository in the Progit book which uses a nice visual to provide a good explanation about recording changes to git repo and also explaining the terms 'tracked' and 'untracked'.

Can I make a <button> not submit a form?

The default value for the type attribute of button elements is "submit". Set it to type="button" to produce a button that doesn't submit the form.

<button type="button">Submit</button>

In the words of the HTML Standard: "Does nothing."

Explain the concept of a stack frame in a nutshell

Programmers may have questions about stack frames not in a broad term (that it is a singe entity in the stack that serves just one function call and keeps return address, arguments and local variables) but in a narrow sense – when the term stack frames is mentioned in context of compiler options.

Whether the author of the question has meant it or not, but the concept of a stack frame from the aspect of compiler options is a very important issue, not covered by the other replies here.

For example, Microsoft Visual Studio 2015 C/C++ compiler has the following option related to stack frames:

  • /Oy (Frame-Pointer Omission)

GCC have the following:

  • -fomit-frame-pointer (Don't keep the frame pointer in a register for functions that don't need one. This avoids the instructions to save, set up and restore frame pointers; it also makes an extra register available in many functions)

Intel C++ Compiler have the following:

  • -fomit-frame-pointer (Determines whether EBP is used as a general-purpose register in optimizations)

which has the following alias:

  • /Oy

Delphi has the following command-line option:

  • -$W+ (Generate Stack Frames)

In that specific sense, from the compiler’s perspective, a stack frame is just the entry and exit code for the routine, that pushes an anchor to the stack – that can also be used for debugging and for exception handling. Debugging tools may scan the stack data and use these anchors for backtracing, while locating call sites in the stack, i.e. to display names of the functions in the order they have been called hierarchically. For Intel architecture, it is push ebp; mov ebp, esp or enter for entry and mov esp, ebp; pop ebp or leave for exit.

That’s why it is very important to understand for a programmer what a stack frame is in when it comes to compiler options – because the compiler can control whether to generate this code or not.

In some cases, the stack frame (entry and exit code for the routine) can be omitted by the compiler, and the variables will directly be accessed via the stack pointer (SP/ESP/RSP) rather than the convenient base pointer (BP/ESP/RSP). Conditions for omission of the stack frame, for example:

  • the function is a leaf function (i.e. an end-entity that doesn’t call other functions);
  • there are no try/finally or try/except or similar constructs, i.e. no exceptions are used;
  • no routines are called with outgoing parameters on the stack;
  • the function has no parameters;
  • the function has no inline assembly code;
  • etc...

Omitting stack frames (entry and exit code for the routine) can make code smaller and faster, but it may also negatively affect the debuggers’ ability to backtrace the data in the stack and to display it to the programmer. These are the compiler options that determine under which conditions a function should have the entry and exit code, for example: (a) always, (b) never, (c) when needed (specifying the conditions).

Setting environment variables via launchd.conf no longer works in OS X Yosemite/El Capitan/macOS Sierra/Mojave?

Here are the commands to restore the old behavior:

# create a script that calls launchctl iterating through /etc/launchd.conf
echo '#!/bin/sh

while read line || [[ -n $line ]] ; do launchctl $line ; done < /etc/launchd.conf;
' > /usr/local/bin/launchd.conf.sh

# make it executable
chmod +x /usr/local/bin/launchd.conf.sh

# launch the script at startup
echo '<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>launchd.conf</string>
  <key>ProgramArguments</key>
  <array>
    <string>sh</string>
    <string>-c</string>
    <string>/usr/local/bin/launchd.conf.sh</string>
  </array>
  <key>RunAtLoad</key>
  <true/>
</dict>
</plist>
' > /Library/LaunchAgents/launchd.conf.plist

Now you can specify commands like setenv JAVA_HOME /Library/Java/Home in /etc/launchd.conf.

Checked on El Capitan.

Tkinter: "Python may not be configured for Tk"

If you're running on an AWS instance that is running Amazon Linux OS, the magic command to fix this for me was

sudo yum install tkinter

If you want to determine your Linux build, try cat /etc/*release

How do I get milliseconds from epoch (1970-01-01) in Java?

You can also try

  Calendar calendar = Calendar.getInstance();
  System.out.println(calendar.getTimeInMillis());

getTimeInMillis() - the current time as UTC milliseconds from the epoch

Transparent CSS background color

In this case background-color:rgba(0,0,0,0.5); is the best way. For example: background-color:rgba(0,0,0,opacity option);

Parameter in like clause JPQL

Use JpaRepository or CrudRepository as repository interface:

@Repository
public interface CustomerRepository extends JpaRepository<Customer, Integer> {

    @Query("SELECT t from Customer t where LOWER(t.name) LIKE %:name%")
    public List<Customer> findByName(@Param("name") String name);

}


@Service(value="customerService")
public class CustomerServiceImpl implements CustomerService {

    private CustomerRepository customerRepository;
    
    //...

    @Override
    public List<Customer> pattern(String text) throws Exception {
        return customerRepository.findByName(text.toLowerCase());
    }
}

How do I move focus to next input with jQuery?

JQuery UI already has this, in my example below I included a maxchar attribute to focus on the next focus-able element (input, select, textarea, button and object) if i typed in the max number of characters

HTML:

text 1 <input type="text" value="" id="txt1" maxchar="5" /><br />
text 2 <input type="text" value="" id="txt2" maxchar="5" /><br />
checkbox 1 <input type="checkbox" value="" id="chk1" /><br />
checkbox 2 <input type="checkbox" value="" id="chk2" /><br />
dropdown 1 <select id="dd1" >
    <option value="1">1</option>
    <option value="1">2</option>
</select><br />
dropdown 2 <select id="dd2">
    <option value="1">1</option>
    <option value="1">2</option>
</select>

Javascript:

$(function() {
    var focusables = $(":focusable");   
    focusables.keyup(function(e) {
        var maxchar = false;
        if ($(this).attr("maxchar")) {
            if ($(this).val().length >= $(this).attr("maxchar"))
                maxchar = true;
            }
        if (e.keyCode == 13 || maxchar) {
            var current = focusables.index(this),
                next = focusables.eq(current+1).length ? focusables.eq(current+1) : focusables.eq(0);
            next.focus();
        }
    });
});

Calling ASP.NET MVC Action Methods from JavaScript

Use jQuery ajax:

function AddToCart(id)
{
   $.ajax({
      url: 'urlToController',
      data: { id: id }
   }).done(function() {
      alert('Added'); 
   });
}

http://api.jquery.com/jQuery.ajax/

How to remove array element in mongodb?

This below code will remove the complete object element from the array, where the phone number is '+1786543589455'

db.collection.update(
  { _id: id },
  { $pull: { 'contact': { number: '+1786543589455' } } }
);

Force the origin to start at 0

Simply add these to your ggplot:

+ scale_x_continuous(expand = c(0, 0), limits = c(0, NA)) + 
  scale_y_continuous(expand = c(0, 0), limits = c(0, NA))

Example

df <- data.frame(x = 1:5, y = 1:5)
p <- ggplot(df, aes(x, y)) + geom_point()
p <- p + expand_limits(x = 0, y = 0)
p # not what you are looking for


p + scale_x_continuous(expand = c(0, 0), limits = c(0,NA)) + 
  scale_y_continuous(expand = c(0, 0), limits = c(0, NA))

enter image description here

Lastly, take great care not to unintentionally exclude data off your chart. For example, a position = 'dodge' could cause a bar to get left off the chart entirely (e.g. if its value is zero and you start the axis at zero), so you may not see it and may not even know it's there. I recommend plotting data in full first, inspect, then use the above tip to improve the plot's aesthetics.

Convert String into a Class Object

You cannot store a class object into a string using toString(), toString() only returns a String representation of your object-in any way you'd like. You might want to do some reading about Serialization.

How to apply bold text style for an entire row using Apache POI?

This work for me

I set style's font before and make rowheader normally then i set in loop for the style with font bolded on each cell of rowhead. Et voilà first row is bolded.

HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("FirstSheet");
HSSFRow rowhead = sheet.createRow(0); 
HSSFCellStyle style = wb.createCellStyle();
HSSFFont font = wb.createFont();
font.setFontName(HSSFFont.FONT_ARIAL);
font.setFontHeightInPoints((short)10);
font.setBold(true);
style.setFont(font);
rowhead.createCell(0).setCellValue("ID");
rowhead.createCell(1).setCellValue("First");
rowhead.createCell(2).setCellValue("Second");
rowhead.createCell(3).setCellValue("Third");
for(int j = 0; j<=3; j++)
rowhead.getCell(j).setCellStyle(style);

Duplicate headers received from server

This ones a little old but was high in the google ranking so I thought I would throw in the answer I found from Chrome, pdf display, Duplicate headers received from the server

Basically my problem also was that the filename contained commas. Do a replace on commas to remove them and you should be fine. My function to make a valid filename is below.

    public static string MakeValidFileName(string name)
    {
        string invalidChars = Regex.Escape(new string(System.IO.Path.GetInvalidFileNameChars()));
        string invalidReStr = string.Format(@"[{0}]+", invalidChars);
        string replace = Regex.Replace(name, invalidReStr, "_").Replace(";", "").Replace(",", "");
        return replace;
    }

Exit codes in Python

Exit codes in many programming languages are up to programmers. So you have to look at your program source code (or manual). Zero usually means "everything went fine".

Simulate delayed and dropped packets on Linux

An easy to use network fault injection tool is Saboteur. It can simulate:

  • Total network partition
  • Remote service dead (not listening on the expected port)
  • Delays
  • Packet loss -TCP connection timeout (as often happens when two systems are separated by a stateful firewall)

How to change fontFamily of TextView in Android

You set style in res/layout/value/style.xml like that:

<style name="boldText">
    <item name="android:textStyle">bold|italic</item>
    <item name="android:textColor">#FFFFFF</item>
</style>

and to use this style in main.xml file use:

style="@style/boldText"

Is there an easy way to reload css without reloading the page?

There is absolutely no need to use jQuery for this. The following JavaScript function will reload all your CSS files:

function reloadCss()
{
    var links = document.getElementsByTagName("link");
    for (var cl in links)
    {
        var link = links[cl];
        if (link.rel === "stylesheet")
            link.href += "";
    }
}

Convert nullable bool? to bool

You can use Nullable{T} GetValueOrDefault() method. This will return false if null.

 bool? nullableBool = null;

 bool actualBool = nullableBool.GetValueOrDefault();

How to use "raise" keyword in Python

raise without any arguments is a special use of python syntax. It means get the exception and re-raise it. If this usage it could have been called reraise.

    raise

From The Python Language Reference:

If no expressions are present, raise re-raises the last exception that was active in the current scope.

If raise is used alone without any argument is strictly used for reraise-ing. If done in the situation that is not at a reraise of another exception, the following error is shown: RuntimeError: No active exception to reraise

How to install the current version of Go in Ubuntu Precise

Or maybe you could use this script to install Go and LiteIDE?

If you are unhappy with the answer provided, please comment instead of blindly down voting. I have used this setup for the last 4 years without any issue.

The Response content must be a string or object implementing __toString(), "boolean" given after move to psql

TL;DR

Just returning response()->json($promotion) won't solve the issue in this question. $promotion is an Eloquent object, which Laravel will automatically json_encode for the response. The json encoding is failing because of the img property, which is a PHP stream resource, and cannot be encoded.

Details

Whatever you return from your controller, Laravel is going to attempt to convert to a string. When you return an object, the object's __toString() magic method will be invoked to make the conversion.

Therefore, when you just return $promotion from your controller action, Laravel is going to call __toString() on it to convert it to a string to display.

On the Model, __toString() calls toJson(), which returns the result of json_encode. Therefore, json_encode is returning false, meaning it is running into an error.

Your dd shows that your img attribute is a stream resource. json_encode cannot encode a resource, so this is probably causing the failure. You should add your img attribute to the $hidden property to remove it from the json_encode.

class Promotion extends Model
{
    protected $hidden = ['img'];

    // rest of class
}

How to bind to a PasswordBox in MVVM

I am using succinct MVVM-friendly solution that hasn't been mentioned yet. First, I name the PasswordBox in XAML:

<PasswordBox x:Name="Password" />

Then I add a single method call into view constructor:

public LoginWindow()
{
    InitializeComponent();
    ExposeControl<LoginViewModel>.Expose(this, view => view.Password,
        (model, box) => model.SetPasswordBox(box));
}

And that's it. View model will receive notification when it is attached to a view via DataContext and another notification when it is detached. The contents of this notification are configurable via the lambdas, but usually it's just a setter or method call on the view model, passing the problematic control as a parameter.

It can be made MVVM-friendly very easily by having the view expose interface instead of child controls.

The above code relies on helper class published on my blog.

Meaning of .Cells(.Rows.Count,"A").End(xlUp).row

It is used to find the how many rows contain data in a worksheet that contains data in the column "A". The full usage is

 lastRowIndex = ws.Cells(ws.Rows.Count, "A").End(xlUp).row

Where ws is a Worksheet object. In the questions example it was implied that the statement was inside a With block

With ws
    lastRowIndex = .Cells(.Rows.Count, "A").End(xlUp).row
End With
  1. ws.Rows.Count returns the total count of rows in the worksheet (1048576 in Excel 2010).
  2. .Cells(.Rows.Count, "A") returns the bottom most cell in column "A" in the worksheet

Then there is the End method. The documentation is ambiguous as to what it does.

Returns a Range object that represents the cell at the end of the region that contains the source range

Particularly it doesn't define what a "region" is. My understanding is a region is a contiguous range of non-empty cells. So the expected usage is to start from a cell in a region and find the last cell in that region in that direction from the original cell. However there are multiple exceptions for when you don't use it like that:

  • If the range is multiple cells, it will use the region of rng.cells(1,1).
  • If the range isn't in a region, or the range is already at the end of the region, then it will travel along the direction until it enters a region and return the first encountered cell in that region.
  • If it encounters the edge of the worksheet it will return the cell on the edge of that worksheet.

So Range.End is not a trivial function.

  1. .row returns the row index of that cell.

npx command not found

npx should come with npm 5.2+, and you have node 5.6 .. I found that when I install node using nvm for Windows, it doesn't download npx. so just install npx globally:

npm i -g npx

In Linux or Mac OS, if you found any permission related errors use sudo before it.

sudo npm i -g npx

Sql Server string to date conversion

Use this:

SELECT convert(datetime, '2018-10-25 20:44:11.500', 121) -- yyyy-mm-dd hh:mm:ss.mmm

And refer to the table in the official documentation for the conversion codes.

Increasing nesting function calls limit

Personally I would suggest this is an error as opposed to a setting that needs adjusting. In my code it was because I had a class that had the same name as a library within one of my controllers and it seemed to trip it up.

Output errors and see where this is being triggered.

How to automatically convert strongly typed enum into int?

This seems impossible with the native enum class, but probably you can mock a enum class with a class:

In this case,

enum class b
{
    B1,
    B2
};

would be equivalent to:

class b {
 private:
  int underlying;
 public:
  static constexpr int B1 = 0;
  static constexpr int B2 = 1;
  b(int v) : underlying(v) {}
  operator int() {
      return underlying;
  }
};

This is mostly equivalent to the original enum class. You can directly return b::B1 for in a function with return type b. You can do switch case with it, etc.

And in the spirit of this example you can use templates (possibly together with other things) to generalize and mock any possible object defined by the enum class syntax.

What is the memory consumption of an object in Java?

It appears that every object has an overhead of 16 bytes on 32-bit systems (and 24-byte on 64-bit systems).

http://algs4.cs.princeton.edu/14analysis/ is a good source of information. One example among many good ones is the following.

enter image description here

http://www.cs.virginia.edu/kim/publicity/pldi09tutorials/memory-efficient-java-tutorial.pdf is also very informative, for example:

enter image description here

jQuery: keyPress Backspace won't fire?

If you want to fire the event only on changes of your input use:

$('.s').bind('input', function(){
  console.log("search!");
  doSearch();
});

Evaluate list.contains string in JSTL

there is no built-in feature to check that - what you would do is write your own tld function which takes a list and an item, and calls the list's contains() method. e.g.

//in your own WEB-INF/custom-functions.tld file add this
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE taglib
        PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
        "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib
        xmlns="http://java.sun.com/xml/ns/j2ee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
        version="2.0"
        >
    <tlib-version>1.0</tlib-version>
    <function>
        <name>contains</name>
        <function-class>com.Yourclass</function-class>
        <function-signature>boolean contains(java.util.List,java.lang.Object)
        </function-signature>
    </function>
</taglib>

Then create a class called Yourclass, and add a static method called contains with the above signature. I m sure the implementation of that method is pretty self explanatory:

package com; // just to illustrate how to represent the package in the tld
public class Yourclass {
   public static boolean contains(List list, Object o) {
      return list.contains(o);
   }
}

Then you can use it in your jsp:

<%@ taglib uri="/WEB-INF/custom-functions.tld" prefix="fn" %>
<c:if test="${  fn:contains( mylist, myValue ) }">style='display:none;'</c:if>

The tag can be used from any JSP in the site.

edit: more info regarding the tld file - more info here

What's the difference between StaticResource and DynamicResource in WPF?

  1. StaticResource uses first value. DynamicResource uses last value.
  2. DynamicResource can be used for nested styling, StaticResource cannot.

Suppose you have this nested Style dictionary. LightGreen is at the root level while Pink is nested inside a Grid.

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Style TargetType="{x:Type Grid}">
        <Style.Resources>
            <Style TargetType="{x:Type Button}" x:Key="ConflictButton">
                <Setter Property="Background" Value="Pink"/>
            </Style>
        </Style.Resources>
    </Style>
    <Style TargetType="{x:Type Button}" x:Key="ConflictButton">
        <Setter Property="Background" Value="LightGreen"/>
    </Style>
</ResourceDictionary>

In view:

<Window x:Class="WpfStyleDemo.ConflictingStyleWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="ConflictingStyleWindow" Height="100" Width="100">
    <Window.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Styles/ConflictingStyle.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Window.Resources>
    <Grid>
        <Button Style="{DynamicResource ConflictButton}" Content="Test"/>
    </Grid>
</Window>

StaticResource will render the button as LightGreen, the first value it found in the style. DynamicResource will override the LightGreen button as Pink as it renders the Grid.

StaticResource StaticResource

DynamicResource DynamicResource

Keep in mind that VS Designer treats DynamicResource as StaticResource. It will get first value. In this case, VS Designer will render the button as LightGreen although it actually ends up as Pink.

StaticResource will throw an error when the root-level style (LightGreen) is removed.

How do I change an HTML selected option using JavaScript?

Change

document.getElementById('personlist').getElementsByTagName('option')[11].selected = 'selected'

to

document.getElementById('personlist').value=Person_ID;

How to get the onclick calling object?

http://docs.jquery.com/Events/jQuery.Event

Try with event.target

Contains the DOM element that issued the event. This can be the element that registered for the event or a child of it.

How can I add new dimensions to a Numpy array?

Alternatively to

image = image[..., np.newaxis]

in @dbliss' answer, you can also use numpy.expand_dims like

image = np.expand_dims(image, <your desired dimension>)

For example (taken from the link above):

x = np.array([1, 2])

print(x.shape)  # prints (2,)

Then

y = np.expand_dims(x, axis=0)

yields

array([[1, 2]])

and

y.shape

gives

(1, 2)

How to stop a vb script running in windows

I can think of at least 2 different ways:

  1. using Task Manager (Ctrl-Shift-Esc), select the process tab, look for a process name cscript.exe or wscript.exe and use End Process.

  2. From the command line you could use taskkill /fi "imagename eq cscript.exe" (change to wscript.exe as needed)

Another way is using scripting and WMI. Here are some hints: look for the Win32_Process class and the Terminate method.

jQuery: how to trigger anchor link's click event

Try the following:

$("#myanchor")[0].click()

As simple as that.

How do I bind a WPF DataGrid to a variable number of columns?

You might be able to do this with AutoGenerateColumns and a DataTemplate. I'm not positive if it would work without a lot of work, you would have to play around with it. Honestly if you have a working solution already I wouldn't make the change just yet unless there's a big reason. The DataGrid control is getting very good but it still needs some work (and I have a lot of learning left to do) to be able to do dynamic tasks like this easily.

Understanding ibeacon distancing

The distance estimate provided by iOS is based on the ratio of the beacon signal strength (rssi) over the calibrated transmitter power (txPower). The txPower is the known measured signal strength in rssi at 1 meter away. Each beacon must be calibrated with this txPower value to allow accurate distance estimates.

While the distance estimates are useful, they are not perfect, and require that you control for other variables. Be sure you read up on the complexities and limitations before misusing this.

When we were building the Android iBeacon library, we had to come up with our own independent algorithm because the iOS CoreLocation source code is not available. We measured a bunch of rssi measurements at known distances, then did a best fit curve to match our data points. The algorithm we came up with is shown below as Java code.

Note that the term "accuracy" here is iOS speak for distance in meters. This formula isn't perfect, but it roughly approximates what iOS does.

protected static double calculateAccuracy(int txPower, double rssi) {
  if (rssi == 0) {
    return -1.0; // if we cannot determine accuracy, return -1.
  }

  double ratio = rssi*1.0/txPower;
  if (ratio < 1.0) {
    return Math.pow(ratio,10);
  }
  else {
    double accuracy =  (0.89976)*Math.pow(ratio,7.7095) + 0.111;    
    return accuracy;
  }
}   

Note: The values 0.89976, 7.7095 and 0.111 are the three constants calculated when solving for a best fit curve to our measured data points. YMMV

What is the difference between the float and integer data type when the size is the same?

Floats are used to store a wider range of number than can be fit in an integer. These include decimal numbers and scientific notation style numbers that can be bigger values than can fit in 32 bits. Here's the deep dive into them: http://en.wikipedia.org/wiki/Floating_point

How would one write object-oriented code in C?

There are several techniques that can be used. The most important one is more how to split the project. We use an interface in our project that is declared in a .h file and the implementation of the object in a .c file. The important part is that all modules that include the .h file see only an object as a void *, and the .c file is the only module who knows the internals of the structure.

Something like this for a class we name FOO as an example:

In the .h file

#ifndef FOO_H_
#define FOO_H_

...
 typedef struct FOO_type FOO_type;     /* That's all the rest of the program knows about FOO */

/* Declaration of accessors, functions */
FOO_type *FOO_new(void);
void FOO_free(FOO_type *this);
...
void FOO_dosomething(FOO_type *this, param ...):
char *FOO_getName(FOO_type *this, etc);
#endif

The C implementation file will be something like that.

#include <stdlib.h>
...
#include "FOO.h"

struct FOO_type {
    whatever...
};


FOO_type *FOO_new(void)
{
    FOO_type *this = calloc(1, sizeof (FOO_type));

    ...
    FOO_dosomething(this, );
    return this;
}

So I give the pointer explicitly to an object to every function of that module. A C++ compiler does it implicitly, and in C we write it explicitly out.

I really use this in my programs, to make sure that my program does not compile in C++, and it has the fine property of being in another color in my syntax highlighting editor.

The fields of the FOO_struct can be modified in one module and another module doesn't even need to be recompiled to be still usable.

With that style I already handle a big part of the advantages of OOP (data encapsulation). By using function pointers, it's even easy to implement something like inheritance, but honestly, it's really only rarely useful.

Unable to start debugging on the web server. Could not start ASP.NET debugging VS 2010, II7, Win 7 x64

Dan,

In addition to Aaron's suggestions, try the following

  • Check that integrated windows authentication is selected in your IIS website
  • Can you debug using Cassini instead of IIS?

How can I use the HTML5 canvas element in IE?

I just used flashcanvas, and I got that working. If you encounter problems, just make sure to read the caveats and whatnot. Particularly, if you create canvas elements dynamically, you need to initialize them explicitly:

if (typeof FlashCanvas != "undefined") {
    FlashCanvas.initElement(canvas);
}

generate random double numbers in c++

This solution requires C++11 (or TR1).

#include <random>

int main()
{
   double lower_bound = 0;
   double upper_bound = 10000;
   std::uniform_real_distribution<double> unif(lower_bound,upper_bound);
   std::default_random_engine re;
   double a_random_double = unif(re);

   return 0;
}

For more details see John D. Cook's "Random number generation using C++ TR1".

See also Stroustrup's "Random number generation".

Remove secure warnings (_CRT_SECURE_NO_WARNINGS) from projects by default in Visual Studio

just copy " _CRT_SECURE_NO_WARNINGS " paste it on projects->properties->c/c++->preprocessor->preprocessor definitions click ok.it will work

How to convert std::string to LPCSTR?

str.c_str() gives you a const char *, which is an LPCSTR (Long Pointer to Constant STRing) -- means that it's a pointer to a 0 terminated string of characters. W means wide string (composed of wchar_t instead of char).

Converting from signed char to unsigned char and back again?

There are two ways to interpret the input data; either -128 is the lowest value, and 127 is the highest (i.e. true signed data), or 0 is the lowest value, 127 is somewhere in the middle, and the next "higher" number is -128, with -1 being the "highest" value (that is, the most significant bit already got misinterpreted as a sign bit in a two's complement notation.

Assuming you mean the latter, the formally correct way is

signed char in = ...
unsigned char out = (in < 0)?(in + 256):in;

which at least gcc properly recognizes as a no-op.

JavaScript global event mechanism

I would recommend giving Trackjs a try.

It's error logging as a service.

It's amazingly simple to set up. Just add one <script> line to each page and that's it. This also means it will be amazingly simple to remove if you decide you don't like it.

There are other services like Sentry (which is open-source if you can host your own server), but it doesn't do what Trackjs does. Trackjs records the user's interaction between their browser and your webserver so that you can actually trace the user steps that led to the error, as opposed to just a file and line number reference (and maybe stack trace).

Convert datetime to Unix timestamp and convert it back in python

If your datetime object represents UTC time, don't use time.mktime, as it assumes the tuple is in your local timezone. Instead, use calendar.timegm:

>>> import datetime, calendar
>>> d = datetime.datetime(1970, 1, 1, 0, 1, 0)
>>> calendar.timegm(d.timetuple())
60

Autonumber value of last inserted row - MS Access / VBA

If DAO use

RS.Move 0, RS.LastModified
lngID = RS!AutoNumberFieldName

If ADO use

cn.Execute "INSERT INTO TheTable.....", , adCmdText + adExecuteNoRecords
Set rs = cn.Execute("SELECT @@Identity", , adCmdText)
Debug.Print rs.Fields(0).Value

cn being a valid ADO connection, @@Identity will return the last Identity (Autonumber) inserted on this connection.

Note that @@Identity might be troublesome because the last generated value may not be the one you are interested in. For the Access database engine, consider a VIEW that joins two tables, both of which have the IDENTITY property, and you INSERT INTO the VIEW. For SQL Server, consider if there are triggers that in turn insert records into another table that also has the IDENTITY property.

BTW DMax would not work as if someone else inserts a record just after you've inserted one but before your Dmax function finishes excecuting, then you would get their record.

Setting background-image using jQuery CSS property

Alternatively to what the others are correctly suggesting, I find it easier usually to toggle CSS classes, instead of individual CSS settings (especially background image URLs). For example:

// in CSS 
.bg1 
{
  background-image: url(/some/image/url/here.jpg);
}

.bg2 
{
  background-image: url(/another/image/url/there.jpg);
}

// in JS
// based on value of imageUrl, determine what class to remove and what class to add.
$('myOjbect').removeClass('bg1').addClass('bg2');

How to use onClick event on react Link component?

I don't believe this is a good pattern to use in general. Link will run your onClick event and then navigate to the route, so there will be a slight delay navigating to the new route. A better strategy is to navigate to the new route with the 'to' prop as you have done, and in the new component's componentDidMount() function you can fire your hello function or any other function. It will give you the same result, but with a much smoother transition between routes.

For context, I noticed this while updating my redux store with an onClick event on Link like you have here, and it caused a ~.3 second blank-white-screen delay before mounting the new route's component. There was no api call involved, so I was surprised the delay was so big. However, if you're just console logging 'hello' the delay might not be noticeable.

What's the best way to use R scripts on the command line (terminal)?

You might want to use python's rpy2 module. However, the "right" way to do this is with R CMD BATCH. You can modify this to write to STDOUT, but the default is to write to a .Rout file. See example below:

[ramanujan:~]$cat foo.R
print(rnorm(10))
[ramanujan:~]$R CMD BATCH foo.R
[ramanujan:~]$cat foo.Rout

R version 2.7.2 (2008-08-25)
Copyright (C) 2008 The R Foundation for Statistical Computing
ISBN 3-900051-07-0

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

[Previously saved workspace restored]


 ~/.Rprofile loaded.
Welcome at  Fri Apr 17 13:33:17 2009
> print(rnorm(10))
 [1]  1.5891276  1.1219071 -0.6110963  0.1579430 -0.3104579  1.0072677 -0.1303165  0.6998849  1.9918643 -1.2390156
>

Goodbye at  Fri Apr 17 13:33:17 2009
> proc.time()
   user  system elapsed
  0.614   0.050   0.721

Note: you'll want to try out the --vanilla and other options to remove all the startup cruft.

How to overlay images

I just got done doing this exact thing in a project. The HTML side looked a bit like this:

<a href="[fullsize]" class="gallerypic" title="">
  <img src="[thumbnail pic]" height="90" width="140" alt="[Gallery Photo]" class="pic" />
  <span class="zoom-icon">
      <img src="/images/misc/zoom.gif" width="32" height="32" alt="Zoom">
  </span>
</a>

Then using CSS:

a.gallerypic{
  width:140px;
  text-decoration:none;
  position:relative;
  display:block;
  border:1px solid #666;
  padding:3px;
  margin-right:5px;
  float:left;
}

a.gallerypic span.zoom-icon{
  visibility:hidden;
  position:absolute;
  left:40%;
  top:35%;
  filter:alpha(opacity=50);
  -moz-opacity:0.5;
  -khtml-opacity: 0.5;
  opacity: 0.5;
}

a.gallerypic:hover span.zoom-icon{
  visibility:visible;
}

I left a lot of the sample in there on the CSS so you can see how I decided to do the style. Note I lowered the opacity so you could see through the magnifying glass.

Hope this helps.

EDIT: To clarify for your example - you could ignore the visibility:hidden; and kill the :hover execution if you wanted, this was just the way I did it.

413 Request Entity Too Large - File Upload Issue

I add the changes directly to my virtualhost instead the global config of nginx, like this:

   server {
     client_max_body_size 100M;
     ...
   }

And then I change the params in php.ini, like the comments above:

   max_input_time = 24000
   max_execution_time = 24000
   upload_max_filesize = 12000M
   post_max_size = 24000M
   memory_limit = 12000M

and what you can not forget is to restart nginx and php-fpm, in centos 7 is like this:

  systemctl restart nginx
  systemctl restart php-fpm

Drop primary key using script in SQL Server database

The answer I got is that variables and subqueries will not work and we have to user dynamic SQL script. The following works:

DECLARE @SQL VARCHAR(4000)
SET @SQL = 'ALTER TABLE dbo.Student DROP CONSTRAINT |ConstraintName| '

SET @SQL = REPLACE(@SQL, '|ConstraintName|', ( SELECT   name
                                               FROM     sysobjects
                                               WHERE    xtype = 'PK'
                                                        AND parent_obj =        OBJECT_ID('Student')))

EXEC (@SQL)

How can I check if a View exists in a Database?

For people checking the existence to drop View use this

From SQL Server 2016 CTP3 you can use new DIE statements instead of big IF wrappers

syntax

DROP VIEW [ IF EXISTS ] [ schema_name . ] view_name [ ...,n ] [ ; ]

Query :

DROP VIEW IF EXISTS view_name

More info here

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

@BindView(R.id.checkbox_id) // if you are using Butterknife
CheckBox yourCheckBox;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.your_activity); 
    yourCheckBox = (CheckBox)findViewById(R.id.checkbox_id);// If your are not using Butterknife (the traditional way)

    yourCheckBox.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            yourObject.setYourProperty(yourCheckBox.isChecked()); //yourCheckBox.isChecked() is the method to know if the checkBox is checked
            Log.d(TAG, "onClick: yourCheckBox = " + yourObject.getYourProperty() );
        }
    });
}

Obviously you have to make your XML with the id of your checkbox :

<CheckBox
    android:id="@+id/checkbox_id"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Your label"
    />

So, the method to know if the check box is checked is : (CheckBox) yourCheckBox.isChecked() it returns true if the check box is checked.

How can I get a side-by-side diff when I do "git diff"?

Several others already mentioned cdiff for git side-by-side diffing but no one gave a full implementation of it.

Setup cdiff:

git clone https://github.com/ymattw/cdiff.git
cd cdiff
ln -s `pwd`/cdiff ~/bin/cdiff
hash -r # refresh your PATH executable in bash (or 'rehash' if you use tcsh)
        # or just create a new terminal

Edit ~/.gitconfig inserting these lines:

[pager]
        diff = false
        show = false

[diff]
        tool = cdiff
        external = "cdiff -s $2 $5 #"

[difftool "cdiff"]
        cmd = cdiff -s \"$LOCAL\" \"$REMOTE\"

[alias]
        showw = show --ext-dif

The pager off is needed for cdiff to work with Diff, it is essentially a pager anyway so this is fine. Difftool will work regardless of these settings.

The show alias is needed because git show only supports external diff tools via argument.

The '#' at the end of the diff external command is important. Git's diff command appends a $@ (all available diff variables) to the diff command, but we only want the two filenames. So we call out those two explicitly with $2 and $5, and then hide the $@ behind a comment which would otherwise confuse sdiff. Resulting in an error that looks like:

fatal: <FILENAME>: no such path in the working tree
Use 'git <command> -- <path>...' to specify paths that do not exist locally.

Git commands that now produce side-by-side diffing:

git diff <SHA1> <SHA2> 
git difftool <SHA1> <SHA2>
git showw <SHA>

Cdiff usage:

'SPACEBAR' - Advances the page of the current file.
'Q'        - Quits current file, thus advancing you to the next file.

You now have side-by-side diff via git diff and difftool. And you have the cdiff python source code for power user customization should you need it.

How To Run PHP From Windows Command Line in WAMPServer

If you want to just run a quick code snippet you can use the -r option:

php -r "echo 'hi';"

-r allows to run code without using script tags <?..?>

Values of disabled inputs will not be submitted

Disabled controls cannot be successful, and a successful control is "valid" for submission. This is the reason why disabled controls don't submit with the form.

set environment variable in python script

Compact solution (provided you don't need other environment variables):

call('sqsub -np {} /homedir/anotherdir/executable'.format(var1).split(),
      env=dict(LD_LIBRARY_PATH=my_path))

Using the env command line tool:

call('env LD_LIBRARY_PATH=my_path sqsub -np {} /homedir/anotherdir/executable'.format(var1).split())

catch specific HTTP error in python

Tims answer seems to me as misleading. Especially when urllib2 does not return expected code. For example this Error will be fatal (believe or not - it is not uncommon one when downloading urls):

AttributeError: 'URLError' object has no attribute 'code'

Fast, but maybe not the best solution would be code using nested try/except block:

import urllib2
try:
    urllib2.urlopen("some url")
except urllib2.HTTPError, err:
    try:
        if err.code == 404:
            # Handle the error
        else:
            raise
    except:
        ...

More information to the topic of nested try/except blocks Are nested try/except blocks in python a good programming practice?

Cordova : Requirements check failed for JDK 1.8 or greater

Guys to get the mix right on Windows, you need to do the following

  1. Download and install any version of JDK 1.8 or higher.
  2. Open environment variables, create an environment variable called JAVA_HOME and set value to JDK install path. C:\Program Files\Java\jdk1.8.0_162 make sure you do not add the \bin in the value.

enter image description here

  1. In your system path variable, put a semi-colon ; and add this value to system path e.g C:\Program Files\Java\jdk1.8.0_162\bin; Here the \bin is added.

Note: The environment variables are tricky.They are supposed to be closed by a ; before opening another. That is why we put one before adding the value and one after the value to close it.

enter image description here

  1. Now close terminal and reopen then run previous commands.

How do I include a JavaScript script file in Angular and call a function from that script?

Add external js file in index.html.

<script src="./assets/vendors/myjs.js"></script>

Here's myjs.js file :

var myExtObject = (function() {

    return {
      func1: function() {
        alert('function 1 called');
      },
      func2: function() {
        alert('function 2 called');
      }
    }

})(myExtObject||{})


var webGlObject = (function() { 
    return { 
      init: function() { 
        alert('webGlObject initialized');
      } 
    } 
})(webGlObject||{})

Then declare it is in component like below

demo.component.ts

declare var myExtObject: any;
declare var webGlObject: any;

constructor(){
    webGlObject.init();
}

callFunction1() {
    myExtObject.func1();
}

callFunction2() {
    myExtObject.func2();
}

demo.component.html

<div>
    <p>click below buttons for function call</p>
    <button (click)="callFunction1()">Call Function 1</button>
    <button (click)="callFunction2()">Call Function 2</button>
</div>

It's working for me...

jQuery validate Uncaught TypeError: Cannot read property 'nodeName' of null

I found this answer when I was getting a similar error for nodeName after upgrading to Bootstrap 4. The issue was that the tabs didn't have the nav and nav-tab classes; adding those to the <ul> element fixed the issue.

Linux: is there a read or recv from socket with timeout?

LINUX

struct timeval tv;
tv.tv_sec = 30;        // 30 Secs Timeout
tv.tv_usec = 0;        // Not init'ing this can cause strange errors
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv,sizeof(struct timeval));

WINDOWS

DWORD timeout = SOCKET_READ_TIMEOUT_SEC * 1000;
setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof(timeout));

NOTE: You have put this setting before bind() function call for proper run

ALTER COLUMN in sqlite

There's no ALTER COLUMN in sqlite.

I believe your only option is to:

  • Rename the table to a temporary name
  • Create a new table without the NOT NULL constraint
  • Copy the content of the old table to the new one
  • Remove the old table

This other Stackoverflow answer explains the process in details

What is the difference between AF_INET and PF_INET in socket programming?

AF_INET = Address Format, Internet = IP Addresses

PF_INET = Packet Format, Internet = IP, TCP/IP or UDP/IP

AF_INET is the address family that is used for the socket you're creating (in this case an Internet Protocol address). The Linux kernel, for example, supports 29 other address families such as UNIX sockets and IPX, and also communications with IRDA and Bluetooth (AF_IRDA and AF_BLUETOOTH, but it is doubtful you'll use these at such a low level).

For the most part sticking with AF_INET for socket programming over a network is the safest option.

Meaning, AF_INET refers to addresses from the internet, IP addresses specifically.

PF_INET refers to anything in the protocol, usually sockets/ports.

Node.js Port 3000 already in use but it actually isn't?

This started happening to me today on Windows. I have restarted my computer and checked that nothing is on the port 3000 and it isn't.

I tried using 3001, 3005 with the same result.

In the end I moved to 8881 and it works now.

The only thing that changed for me was installing windows updates and updating source-map-explorer. As this also occurs in other apps its either something with Web Storm or windows. My guess is the ports may be locked down but the ones in the 88XX range are not.

Swift: declare an empty dictionary

You can't use [:] unless type information is available.

You need to provide it explicitly in this case:

var dict = Dictionary<String, String>()

var means it's mutable, so you can add entries to it. Conversely, if you make it a let then you cannot further modify it (let means constant).

You can use the [:] shorthand notation if the type information can be inferred, for instance

var dict = ["key": "value"]

// stuff

dict = [:] // ok, I'm done with it

In the last example the dictionary is known to have a type Dictionary<String, String> by the first line. Note that you didn't have to specify it explicitly, but it has been inferred.

Scrollview vertical and horizontal in android

Mixing some of the suggestions above, and was able to get a good solution:

Custom ScrollView:

package com.scrollable.view;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.ScrollView;

public class VScroll extends ScrollView {

    public VScroll(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public VScroll(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public VScroll(Context context) {
        super(context);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return false;
    }
}

Custom HorizontalScrollView:

package com.scrollable.view;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.HorizontalScrollView;

public class HScroll extends HorizontalScrollView {

    public HScroll(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public HScroll(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public HScroll(Context context) {
        super(context);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return false;
    }
}

the ScrollableImageActivity:

package com.scrollable.view;

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.widget.HorizontalScrollView;
import android.widget.ScrollView;

public class ScrollableImageActivity extends Activity {

    private float mx, my;
    private float curX, curY;

    private ScrollView vScroll;
    private HorizontalScrollView hScroll;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        vScroll = (ScrollView) findViewById(R.id.vScroll);
        hScroll = (HorizontalScrollView) findViewById(R.id.hScroll);

    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        float curX, curY;

        switch (event.getAction()) {

            case MotionEvent.ACTION_DOWN:
                mx = event.getX();
                my = event.getY();
                break;
            case MotionEvent.ACTION_MOVE:
                curX = event.getX();
                curY = event.getY();
                vScroll.scrollBy((int) (mx - curX), (int) (my - curY));
                hScroll.scrollBy((int) (mx - curX), (int) (my - curY));
                mx = curX;
                my = curY;
                break;
            case MotionEvent.ACTION_UP:
                curX = event.getX();
                curY = event.getY();
                vScroll.scrollBy((int) (mx - curX), (int) (my - curY));
                hScroll.scrollBy((int) (mx - curX), (int) (my - curY));
                break;
        }

        return true;
    }

}

the layout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <com.scrollable.view.VScroll android:layout_height="fill_parent"
        android:layout_width="fill_parent" android:id="@+id/vScroll">
        <com.scrollable.view.HScroll android:id="@+id/hScroll"
            android:layout_width="fill_parent" android:layout_height="fill_parent">
            <ImageView android:layout_width="fill_parent" android:layout_height="fill_parent" android:src="@drawable/bg"></ImageView>
        </com.scrollable.view.HScroll>
    </com.scrollable.view.VScroll>

</LinearLayout>

Recursion or Iteration?

Recursion is more costly in memory, as each recursive call generally requires a memory address to be pushed to the stack - so that later the program could return to that point.

Still, there are many cases in which recursion is a lot more natural and readable than loops - like when working with trees. In these cases I would recommend sticking to recursion.

XPath with multiple conditions

Try:
//category[@name='Sport' and ./author/text()='James Small']

When to use 'raise NotImplementedError'?

One could also do a raise NotImplementedError() inside the child method of an @abstractmethod-decorated base class method.


Imagine writing a control script for a family of measurement modules (physical devices). The functionality of each module is narrowly-defined, implementing just one dedicated function: one could be an array of relays, another a multi-channel DAC or ADC, another an ammeter etc.

Much of the low-level commands in use would be shared between the modules for example to read their ID numbers or to send a command to them. Let's see what we have at this point:

Base Class

from abc import ABC, abstractmethod  #< we'll make use of these later

class Generic(ABC):
    ''' Base class for all measurement modules. '''

    # Shared functions
    def __init__(self):
        # do what you must...

    def _read_ID(self):
        # same for all the modules

    def _send_command(self, value):
        # same for all the modules

Shared Verbs

We then realise that much of the module-specific command verbs and, therefore, the logic of their interfaces is also shared. Here are 3 different verbs whose meaning would be self-explanatory considering a number of target modules.

  • get(channel)

  • relay: get the on/off status of the relay on channel

  • DAC: get the output voltage on channel

  • ADC: get the input voltage on channel

  • enable(channel)

  • relay: enable the use of the relay on channel

  • DAC: enable the use of the output channel on channel

  • ADC: enable the use of the input channel on channel

  • set(channel)

  • relay: set the relay on channel on/off

  • DAC: set the output voltage on channel

  • ADC: hmm... nothing logical comes to mind.


Shared Verbs Become Enforced Verbs

I'd argue that there is a strong case for the above verbs to be shared across the modules as we saw that their meaning is evident for each one of them. I'd continue writing my base class Generic like so:

class Generic(ABC):  # ...continued
    
    @abstractmethod
    def get(self, channel):
        pass

    @abstractmethod
    def enable(self, channel):
        pass

    @abstractmethod
    def set(self, channel):
        pass

Subclasses

We now know that our subclasses will all have to define these methods. Let's see what it could look like for the ADC module:

class ADC(Generic):

    def __init__(self):
        super().__init__()  #< applies to all modules
        # more init code specific to the ADC module
    
    def get(self, channel):
        # returns the input voltage measured on the given 'channel'

    def enable(self, channel):
        # enables accessing the given 'channel'

You may now be wondering:

But this won't work for the ADC module as set makes no sense there as we've just seen this above!

You're right: not implementing set is not an option as Python would then fire the error below when you tried to instantiate your ADC object.

TypeError: Can't instantiate abstract class 'ADC' with abstract methods 'set'

So you must implement something, because we made set an enforced verb (aka '@abstractmethod'), which is shared by two other modules but, at the same time, you must also not implement anything as set does not make sense for this particular module.

NotImplementedError to the Rescue

By completing the ADC class like this:

class ADC(Generic): # ...continued

    def set(self, channel):
        raise NotImplementedError("Can't use 'set' on an ADC!")

You are doing three very good things at once:

  1. You are protecting a user from erroneously issuing a command ('set') that is not (and shouldn't!) be implemented for this module.
  2. You are telling them explicitly what the problem is (see TemporalWolf's link about 'Bare exceptions' for why this is important)
  3. You are protecting the implementation of all the other modules for which the enforced verbs do make sense. I.e. you ensure that those modules for which these verbs do make sense will implement these methods and that they will do so using exactly these verbs and not some other ad-hoc names.

Is there any option to limit mongodb memory usage?

For Windows it seems possible to control the amount of memory MongoDB uses, see this tutorial at Captain Codeman:

Limit MongoDB memory use on Windows without Virtualization

Insert using LEFT JOIN and INNER JOIN

INSERT INTO Test([col1],[col2]) (
    SELECT 
        a.Name AS [col1],
        b.sub AS [col2] 
    FROM IdTable b 
    INNER JOIN Nametable a ON b.no = a.no
)

List comprehension on a nested list?

Here is how to convert nested for loop to nested list comprehension:

enter image description here

Here is how nested list comprehension works:

            l a b c d e f
            ? ? ? ? ? ? ?
In [1]: l = [ [ [ [ [ [ 1 ] ] ] ] ] ]
In [2]: for a in l:
   ...:     for b in a:
   ...:         for c in b:
   ...:             for d in c:
   ...:                 for e in d:
   ...:                     for f in e:
   ...:                         print(float(f))
   ...:                         
1.0

In [3]: [float(f)
         for a in l
   ...:     for b in a
   ...:         for c in b
   ...:             for d in c
   ...:                 for e in d
   ...:                     for f in e]
Out[3]: [1.0]

For your case, it will be something like this.

In [4]: new_list = [float(y) for x in l for y in x]

How do I execute external program within C code in linux with arguments?

Here's the way to extend to variable args when you don't have the args hard coded (although they are still technically hard coded in this example, but should be easy to figure out how to extend...):

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int argcount = 3;
const char* args[] = {"1", "2", "3"};
const char* binary_name = "mybinaryname";
char myoutput_array[5000];

sprintf(myoutput_array, "%s", binary_name);
for(int i = 0; i < argcount; ++i)
{
    strcat(myoutput_array, " ");
    strcat(myoutput_array, args[i]);
}
system(myoutput_array);

Python using enumerate inside list comprehension

Here's a way to do it:

>>> mylist = ['a', 'b', 'c', 'd']
>>> [item for item in enumerate(mylist)]
[(0, 'a'), (1, 'b'), (2, 'c'), (3, 'd')]

Alternatively, you can do:

>>> [(i, j) for i, j in enumerate(mylist)]
[(0, 'a'), (1, 'b'), (2, 'c'), (3, 'd')]

The reason you got an error was that you were missing the () around i and j to make it a tuple.

JavaScript array to CSV

The following code were written in ES6 and it will work in most of the browsers without an issue.

_x000D_
_x000D_
var test_array = [["name1", 2, 3], ["name2", 4, 5], ["name3", 6, 7], ["name4", 8, 9], ["name5", 10, 11]];_x000D_
_x000D_
// Construct the comma seperated string_x000D_
// If a column values contains a comma then surround the column value by double quotes_x000D_
const csv = test_array.map(row => row.map(item => (typeof item === 'string' && item.indexOf(',') >= 0) ? `"${item}"`: String(item)).join(',')).join('\n');_x000D_
_x000D_
// Format the CSV string_x000D_
const data = encodeURI('data:text/csv;charset=utf-8,' + csv);_x000D_
_x000D_
// Create a virtual Anchor tag_x000D_
const link = document.createElement('a');_x000D_
link.setAttribute('href', data);_x000D_
link.setAttribute('download', 'export.csv');_x000D_
_x000D_
// Append the Anchor tag in the actual web page or application_x000D_
document.body.appendChild(link);_x000D_
_x000D_
// Trigger the click event of the Anchor link_x000D_
link.click();_x000D_
_x000D_
// Remove the Anchor link form the web page or application_x000D_
document.body.removeChild(link);
_x000D_
_x000D_
_x000D_

Naming threads and thread-pools of ExecutorService

I use to do same like below (requires guava library) :

ThreadFactory namedThreadFactory = new ThreadFactoryBuilder().setNameFormat("SO-POOL-%d").build();
ExecutorService executorService = Executors.newFixedThreadPool(5,namedThreadFactory);

Is there a RegExp.escape function in JavaScript?

Rather than only escaping characters which will cause issues in your regular expression (e.g.: a blacklist), consider using a whitelist instead. This way each character is considered tainted unless it matches.

For this example, assume the following expression:

RegExp.escape('be || ! be');

This whitelists letters, number and spaces:

RegExp.escape = function (string) {
    return string.replace(/([^\w\d\s])/gi, '\\$1');
}

Returns:

"be \|\| \! be"

This may escape characters which do not need to be escaped, but this doesn't hinder your expression (maybe some minor time penalties - but it's worth it for safety).

Python debugging tips

the obvious way to debug a script

python -m pdb script.py
  • useful when that script raises an exception
  • useful when using virtualenv and pdb command is not running with the venvs python version.

if you don't know exactly where that script is

python -m pdb ``which <python-script-name>``

XSL xsl:template match="/"

The match attribute indicates on which parts the template transformation is going to be applied. In that particular case the "/" means the root of the xml document. The value you have to provide into the match attribute should be XPath expression. XPath is the language you have to use to refer specific parts of the target xml file.

To gain a meaningful understanding of what else you can put into match attribute you need to understand what xpath is and how to use it. I suggest yo look at links I've provided for youat the bottom of the answer.

Could I write "table" or any other html tag instead of "/" ?

Yes you can. But this depends what exactly you are trying to do. if your target xml file contains HMTL elements and you are triyng to apply this xsl:template on them it makes sense to use table, div or anithing else.

Here a few links:

How to convert a column of DataTable to a List

Try this:

static void Main(string[] args)
{
    var dt = new DataTable
    {
        Columns = { { "Lastname",typeof(string) }, { "Firstname",typeof(string) } }
    };
    dt.Rows.Add("Lennon", "John");
    dt.Rows.Add("McCartney", "Paul");
    dt.Rows.Add("Harrison", "George");
    dt.Rows.Add("Starr", "Ringo");

    List<string> s = dt.AsEnumerable().Select(x => x[0].ToString()).ToList();

    foreach(string e in s)
        Console.WriteLine(e);

    Console.ReadLine();
}

How to get the browser language using JavaScript

Try this script to get your browser language

_x000D_
_x000D_
<script type="text/javascript">_x000D_
var userLang = navigator.language || navigator.userLanguage; _x000D_
alert ("The language is: " + userLang);_x000D_
</script>
_x000D_
_x000D_
_x000D_

Cheers

How to affect other elements when one element is hovered

In this particular example, you can use:

#container:hover #cube {
    background-color: yellow;   
}

This example only works since cube is a child of container. For more complicated scenarios, you'd need to use different CSS, or use JavaScript.

Visual Studio: Relative Assembly References Paths

Yes, just create a directory in your solution like lib/, and then add your dll to that directory in the filesystem and add it in the project (Add->Existing Item->etc). Then add the reference based on your project.

I have done this several times under svn and under cvs.

A JSONObject text must begin with '{' at 1 [character 2 line 1] with '{' error

in my case my arraylist trhows me that error with the JSONObject , but i fin this solution for my array of String objects

List<String> listStrings= new ArrayList<String>();
String json = new Gson().toJson(listStrings);
return json;

Works like charm with angular Gson version 2.8.5

Referencing value in a closed Excel workbook using INDIRECT?

There is definitively no way to do this with standard formulas. However, a crazy sort of answer can be found here. It still avoids VBA, and it will allow you to get your result dynamically.

  1. First, make the formula that will generate your formula, but don't add the = at the beginning!

  2. Let us pretend that you have created this formula in cell B2 of Sheet1, and you would like the formula to be evaluated in column c.

  3. Now, go to the Formulas tab, and choose "Define Name". Give it the name myResult (or whatever you choose), and under Refers To, write =evaluate(Sheet1!$B2) (note the $)

  4. Finally, go to C2, and write =myResult. Drag down, and... voila!

Get a list of numbers as input from the user

try this one ,

n=int(raw_input("Enter length of the list"))
l1=[]
for i in range(n):
    a=raw_input()
    if(a.isdigit()):
        l1.insert(i,float(a)) #statement1
    else:
        l1.insert(i,a)        #statement2

If the element of the list is just a number the statement 1 will get executed and if it is a string then statement 2 will be executed. In the end you will have an list l1 as you needed.

How can I auto hide alert box after it showing it?

impossible with javascript. Just as another alternative to suggestions from other answers: consider using jGrowl: http://archive.plugins.jquery.com/project/jGrowl

It is more efficient to use if-return-return or if-else-return?

From Chromium's style guide:

Don't use else after return:

# Bad
if (foo)
  return 1
else
  return 2

# Good
if (foo)
  return 1
return 2

return 1 if foo else 2

How can I align YouTube embedded video in the center in bootstrap

You dont have to put <iframe> in a parent div at all. You can target exactly youtube iframe with CSS/3:

iframe[src*="//youtube.com/"], iframe[src*="//www.youtube.com/"] {
   display: block;
   margin: 0 auto;
}

Sending images using Http Post

Version 4.3.5 Updated Code

  • httpclient-4.3.5.jar
  • httpcore-4.3.2.jar
  • httpmime-4.3.5.jar

Since MultipartEntity has been deprecated. Please see the code below.

String responseBody = "failure";
HttpClient client = new DefaultHttpClient();
client.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1);

String url = WWPApi.URL_USERS;
Map<String, String> map = new HashMap<String, String>();
map.put("user_id", String.valueOf(userId));
map.put("action", "update");
url = addQueryParams(map, url);

HttpPost post = new HttpPost(url);
post.addHeader("Accept", "application/json");

MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.setCharset(MIME.UTF8_CHARSET);

if (career != null)
    builder.addTextBody("career", career, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (gender != null)
    builder.addTextBody("gender", gender, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (username != null)
    builder.addTextBody("username", username, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (email != null)
    builder.addTextBody("email", email, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (password != null)
    builder.addTextBody("password", password, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (country != null)
    builder.addTextBody("country", country, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (file != null)
    builder.addBinaryBody("Filedata", file, ContentType.MULTIPART_FORM_DATA, file.getName());

post.setEntity(builder.build());

try {
    responseBody = EntityUtils.toString(client.execute(post).getEntity(), "UTF-8");
//  System.out.println("Response from Server ==> " + responseBody);

    JSONObject object = new JSONObject(responseBody);
    Boolean success = object.optBoolean("success");
    String message = object.optString("error");

    if (!success) {
        responseBody = message;
    } else {
        responseBody = "success";
    }

} catch (Exception e) {
    e.printStackTrace();
} finally {
    client.getConnectionManager().shutdown();
}

jQuery select box validation

simplify the whole thing a bit, fix some issues with commas which will blow up some browsers:

  $(document).ready(function () {
       $("#register").validate({
           debug: true,
           rules: {
               year: {
                   required: function () {
                       return ($("#year option:selected").val() == "0");
                   }
               }
           },
           messages: {
               year: "Year Required"
           }
       });
   });

Jumping to an assumption, should your select not have this attribute validate="required:true"?

How to uncheck a radio button?

function setRadio(obj) 
{
    if($("input[name='r_"+obj.value+"']").val() == 0 ){
      obj.checked = true
     $("input[name='r_"+obj.value+"']").val(1);
    }else{
      obj.checked = false;
      $("input[name='r_"+obj.value+"']").val(0);
    }

}

<input type="radio" id="planoT" name="planoT[{ID_PLANO}]" value="{ID_PLANO}" onclick="setRadio(this)" > <input type="hidden" id="r_{ID_PLANO}" name="r_{ID_PLANO}" value="0" >

:D

How can I change the app display name build with Flutter?

The way of changing the name for iOS and Android is clearly mentioned in the documentation as follows:

But, the case of iOS after you change the Display Name from Xcode, you are not able to run the application in the Flutter way, like flutter run.

Because the Flutter run expects the app name as Runner. Even if you change the name in Xcode, it doesn't work.

So, I fixed this as follows:

Move to the location on your Flutter project, ios/Runner.xcodeproj/project.pbxproj, and find and replace all instances of your new name with Runner.

Then everything should work in the flutter run way.

But don't forget to change the name display name on your next release time. Otherwise, the App Store rejects your name.

What is the HTML tabindex attribute?

The HTML tabindex atribute is responsible for indicating if an element is reachable by keyboard navigation. When the user presses the Tab key the focus is shifted from one element to another. By using the tabindex atribute, the tab order flow is shifted.

Setting width/height as percentage minus pixels

For a bit of a different approach you could use something like this on the list:

position: absolute;
top: 18px;
bottom: 0px;
width: 100%;

This works as long as the parent container has position: relative;

Action Bar's onClick listener for the Home button

if anyone else need the solution

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

    if (id == android.R.id.home) {
        onBackPressed();  return true;
    }

    return super.onOptionsItemSelected(item);
}

How do I schedule a task to run at periodic intervals?

Use timer.scheduleAtFixedRate

public void scheduleAtFixedRate(TimerTask task,
                                long delay,
                                long period)

Schedules the specified task for repeated fixed-rate execution, beginning after the specified delay. Subsequent executions take place at approximately regular intervals, separated by the specified period.
In fixed-rate execution, each execution is scheduled relative to the scheduled execution time of the initial execution. If an execution is delayed for any reason (such as garbage collection or other background activity), two or more executions will occur in rapid succession to "catch up." In the long run, the frequency of execution will be exactly the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-rate execution is appropriate for recurring activities that are sensitive to absolute time, such as ringing a chime every hour on the hour, or running scheduled maintenance every day at a particular time. It is also appropriate for recurring activities where the total time to perform a fixed number of executions is important, such as a countdown timer that ticks once every second for ten seconds. Finally, fixed-rate execution is appropriate for scheduling multiple repeating timer tasks that must remain synchronized with respect to one another.

Parameters:

  • task - task to be scheduled.
  • delay - delay in milliseconds before task is to be executed.
  • period - time in milliseconds between successive task executions.

Throws:

  • IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative.
  • IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated.

"Untrusted App Developer" message when installing enterprise iOS Application

On iOS 9:

Settings -> General -> Device Management -> Developer app / your Apple ID -> Add/remove trust there

How do you create a yes/no boolean field in SQL server?

The equivalent is a BIT field.

In SQL you use 0 and 1 to set a bit field (just as a yes/no field in Access). In Management Studio it displays as a false/true value (at least in recent versions).

When accessing the database through ASP.NET it will expose the field as a boolean value.

.NET / C# - Convert char[] to string

Use the constructor of string which accepts a char[]

char[] c = ...;
string s = new string(c);

How to implement a binary tree?

This implementation supports insert, find and delete operations without destroy the structure of the tree. This is not a banlanced tree.

# Class for construct the nodes of the tree. (Subtrees)
class Node:
def __init__(self, key, parent_node = None):
    self.left = None
    self.right = None
    self.key = key
    if parent_node == None:
        self.parent = self
    else:
        self.parent = parent_node

# Class with the  structure of the tree. 
# This Tree is not balanced.
class Tree:
def __init__(self):
    self.root = None

# Insert a single element
def insert(self, x):
    if(self.root == None):
        self.root = Node(x)
    else:
        self._insert(x, self.root)

def _insert(self, x, node):
    if(x < node.key):
        if(node.left == None):
            node.left = Node(x, node)
        else:
            self._insert(x, node.left)
    else:
        if(node.right == None):
            node.right = Node(x, node)
        else:
            self._insert(x, node.right)

# Given a element, return a node in the tree with key x. 
def find(self, x):
    if(self.root == None):
        return None
    else:
        return self._find(x, self.root)
def _find(self, x, node):
    if(x == node.key):
        return node
    elif(x < node.key):
        if(node.left == None):
            return None
        else:
            return self._find(x, node.left)
    elif(x > node.key):
        if(node.right == None):
            return None
        else:
            return self._find(x, node.right)

# Given a node, return the node in the tree with the next largest element.
def next(self, node):
    if node.right != None:
        return self._left_descendant(node.right)
    else:
        return self._right_ancestor(node)

def _left_descendant(self, node):
    if node.left == None:
        return node
    else:
        return self._left_descendant(node.left)

def _right_ancestor(self, node):
    if node.key <= node.parent.key:
        return node.parent
    else:
        return self._right_ancestor(node.parent)

# Delete an element of the tree
def delete(self, x):
    node = self.find(x)
    if node == None:
        print(x, "isn't in the tree")
    else:
        if node.right == None:
            if node.left == None:
                if node.key < node.parent.key:
                    node.parent.left = None
                    del node # Clean garbage
                else:
                    node.parent.right = None
                    del Node # Clean garbage
            else:
                node.key = node.left.key
                node.left = None
        else:
            x = self.next(node)
            node.key = x.key
            x = None


# tests
t = Tree()
t.insert(5)
t.insert(8)
t.insert(3)
t.insert(4)
t.insert(6)
t.insert(2)

t.delete(8)
t.delete(5)

t.insert(9)
t.insert(1)

t.delete(2)
t.delete(100)

# Remember: Find method return the node object. 
# To return a number use t.find(nº).key
# But it will cause an error if the number is not in the tree.
print(t.find(5)) 
print(t.find(8))
print(t.find(4))
print(t.find(6))
print(t.find(9))

How to check if a String contains only ASCII?

From Guava 19.0 onward, you may use:

boolean isAscii = CharMatcher.ascii().matchesAllOf(someString);

This uses the matchesAllOf(someString) method which relies on the factory method ascii() rather than the now deprecated ASCII singleton.

Here ASCII includes all ASCII characters including the non-printable characters lower than 0x20 (space) such as tabs, line-feed / return but also BEL with code 0x07 and DEL with code 0x7F.

This code incorrectly uses characters rather than code points, even if code points are indicated in the comments of earlier versions. Fortunately, the characters required to create code point with a value of U+010000 or over uses two surrogate characters with a value outside of the ASCII range. So the method still succeeds in testing for ASCII, even for strings containing emoji's.

For earlier Guava versions without the ascii() method you may write:

boolean isAscii = CharMatcher.ASCII.matchesAllOf(someString);

Json.net serialize/deserialize derived types?

Use this JsonKnownTypes, it's very similar way to use, it just add discriminator to json:

[JsonConverter(typeof(JsonKnownTypeConverter<BaseClass>))]
[JsonKnownType(typeof(Base), "base")]
[JsonKnownType(typeof(Derived), "derived")]
public class Base
{
    public string Name;
}
public class Derived : Base
{
    public string Something;
}

Now when you serialize object in json will be add "$type" with "base" and "derived" value and it will be use for deserialize

Serialized list example:

[
    {"Name":"some name", "$type":"base"},
    {"Name":"some name", "Something":"something", "$type":"derived"}
]

Align two divs horizontally side by side center to the page using bootstrap css

Make sure you wrap your "row" inside the class "container" . Also add reference to bootstrap in your html.
Something like this should work:
<html lang="en">
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
</head>
 <body>
     <p>lets learn!</p>
  <div class="container">
          <div class="row">
              <div class="col-lg-6" style="background-color: red;">
                  ONE
              </div>
              <div class="col-lg-2" style="background-color: blue;">
                  TWO
              </div>
              <div class="col-lg-4" style="background-color: green;">
              THREE
           </div>
          </div>
      </div>
 </body>
 </html>

Get selected option text with JavaScript

Use -

$.trim($("select").children("option:selected").text())   //cat

Here is the fiddle - http://jsfiddle.net/eEGr3/

How can you test if an object has a specific property?

I ended up with the following function ...

function HasNoteProperty(
    [object]$testObject,
    [string]$propertyName
)
{
    $members = Get-Member -InputObject $testObject 
    if ($members -ne $null -and $members.count -gt 0) 
    { 
        foreach($member in $members) 
        { 
            if ( ($member.MemberType -eq "NoteProperty" )  -and `
                 ($member.Name       -eq $propertyName) ) 
            { 
                return $true 
            } 
        } 
        return $false 
    } 
    else 
    { 
        return $false; 
    }
}

Are vectors passed to functions by value or by reference in C++

void foo(vector<int> test)

vector would be passed by value in this.

You have more ways to pass vectors depending on the context:-

1) Pass by reference:- This will let function foo change your contents of the vector. More efficient than pass by value as copying of vector is avoided.

2) Pass by const-reference:- This is efficient as well as reliable when you don't want function to change the contents of the vector.

How to count the number of words in a sentence, ignoring numbers, punctuation and whitespace?

    def wordCount(mystring):  
        tempcount = 0  
        count = 1  

        try:  
            for character in mystring:  
                if character == " ":  
                    tempcount +=1  
                    if tempcount ==1:  
                        count +=1  

                    else:  
                        tempcount +=1
                 else:
                     tempcount=0

             return count  

         except Exception:  
             error = "Not a string"  
             return error  

    mystring = "I   am having   a    very nice 23!@$      day."           

    print(wordCount(mystring))  

output is 8

How to change an image on click using CSS alone?

You could use an <a> tag with different styles:

a:link    { }
a:visited { }
a:hover   { }
a:active  { }

I'd recommend using that in conjunction with CSS sprites: https://css-tricks.com/css-sprites/

Rails Model find where not equal

Rails 4

GroupUser.where.not(user_id: me)

What is <scope> under <dependency> in pom.xml for?

added good images with explain scopes

enter image description here

enter image description here

Install a Nuget package in Visual Studio Code

From the command line or the Terminal windows in vs code editor dotnet add package Newtonsoft.Json

See this article by Scott Hanselman

How to exit from Python without traceback?

# Pygame Example  

import pygame, sys  
from pygame.locals import *

pygame.init()  
DISPLAYSURF = pygame.display.set_mode((400, 300))  
pygame.display.set_caption('IBM Emulator')

BLACK = (0, 0, 0)  
GREEN = (0, 255, 0)

fontObj = pygame.font.Font('freesansbold.ttf', 32)  
textSurfaceObj = fontObj.render('IBM PC Emulator', True, GREEN,BLACK)  
textRectObj = textSurfaceObj.get_rect()  
textRectObj = (10, 10)

try:  
    while True: # main loop  
        DISPLAYSURF.fill(BLACK)  
        DISPLAYSURF.blit(textSurfaceObj, textRectObj)  
        for event in pygame.event.get():  
            if event.type == QUIT:  
                pygame.quit()  
                sys.exit()  
        pygame.display.update()  
except SystemExit:  
    pass

Convert array to string in NodeJS

In node, you can just say

console.log(aa)

and it will format it as it should.

If you need to use the resulting string you should use

JSON.stringify(aa)

How to randomize Excel rows

Perhaps the whole column full of random numbers is not the best way to do it, but it seems like probably the most practical as @mariusnn mentioned.

On that note, this stomped me for a while with Office 2010, and while generally answers like the one in lifehacker work,I just wanted to share an extra step required for the numbers to be unique:

  1. Create a new column next to the list that you're going to randomize
  2. Type in =rand() in the first cell of the new column - this will generate a random number between 0 and 1
  3. Fill the column with that formula. The easiest way to do this may be to:

    • go down along the new column up until the last cell that you want to randomize
    • hold down Shift and click on the last cell
    • press Ctrl+D
  4. Now you should have a column of identical numbers, even though they are all generated randomly.

    Random numbers... that are the same...

    The trick here is to recalculate them! Go to the Formulas tab and then click on Calculate Now (or press F9).

    Actually random numbers!

    Now all the numbers in the column will be actually generated randomly.

  5. Go to the Home tab and click on Sort & Filter. Choose whichever order you want (Smallest to Largest or Largest to Smallest) - whichever one will give you a random order with respect to the original order. Then click OK when the Sort Warning prompts you to Expand the selection.

  6. Your list should be randomized now! You can get rid of the column of random numbers if you want.

How can I send an email by Java application using GMail, Yahoo, or Hotmail?

First download the JavaMail API and make sure the relevant jar files are in your classpath.

Here's a full working example using GMail.

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;

public class Main {

    private static String USER_NAME = "*****";  // GMail user name (just the part before "@gmail.com")
    private static String PASSWORD = "********"; // GMail password
    private static String RECIPIENT = "[email protected]";

    public static void main(String[] args) {
        String from = USER_NAME;
        String pass = PASSWORD;
        String[] to = { RECIPIENT }; // list of recipient email addresses
        String subject = "Java send mail example";
        String body = "Welcome to JavaMail!";

        sendFromGMail(from, pass, to, subject, body);
    }

    private static void sendFromGMail(String from, String pass, String[] to, String subject, String body) {
        Properties props = System.getProperties();
        String host = "smtp.gmail.com";
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.user", from);
        props.put("mail.smtp.password", pass);
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");

        Session session = Session.getDefaultInstance(props);
        MimeMessage message = new MimeMessage(session);

        try {
            message.setFrom(new InternetAddress(from));
            InternetAddress[] toAddress = new InternetAddress[to.length];

            // To get the array of addresses
            for( int i = 0; i < to.length; i++ ) {
                toAddress[i] = new InternetAddress(to[i]);
            }

            for( int i = 0; i < toAddress.length; i++) {
                message.addRecipient(Message.RecipientType.TO, toAddress[i]);
            }

            message.setSubject(subject);
            message.setText(body);
            Transport transport = session.getTransport("smtp");
            transport.connect(host, from, pass);
            transport.sendMessage(message, message.getAllRecipients());
            transport.close();
        }
        catch (AddressException ae) {
            ae.printStackTrace();
        }
        catch (MessagingException me) {
            me.printStackTrace();
        }
    }
}

Naturally, you'll want to do more in the catch blocks than print the stack trace as I did in the example code above. (Remove the catch blocks to see which method calls from the JavaMail API throw exceptions so you can better see how to properly handle them.)


Thanks to @jodonnel and everyone else who answered. I'm giving him a bounty because his answer led me about 95% of the way to a complete answer.

How to give ASP.NET access to a private key in a certificate in the certificate store?

If you are trying to load a cert from a .pfx file in IIS the solution may be as simple as enabling this option for the Application Pool.

Right click on the App Pool and select Advanced Settings.

Then enable Load User Profile


enter image description here

Django - taking values from POST request

Read about request objects that your views receive: https://docs.djangoproject.com/en/dev/ref/request-response/#httprequest-objects

Also your hidden field needs a reliable name and then a value:

<input type="hidden" name="title" value="{{ source.title }}">

Then in a view:

request.POST.get("title", "")

Query grants for a table in postgres

Here is a script which generates grant queries for a particular table. It omits owner's privileges.

SELECT 
    format (
      'GRANT %s ON TABLE %I.%I TO %I%s;',
      string_agg(tg.privilege_type, ', '),
      tg.table_schema,
      tg.table_name,
      tg.grantee,
      CASE
        WHEN tg.is_grantable = 'YES' 
        THEN ' WITH GRANT OPTION' 
        ELSE '' 
      END
    )
  FROM information_schema.role_table_grants tg
  JOIN pg_tables t ON t.schemaname = tg.table_schema AND t.tablename = tg.table_name
  WHERE
    tg.table_schema = 'myschema' AND
    tg.table_name='mytable' AND
    t.tableowner <> tg.grantee
  GROUP BY tg.table_schema, tg.table_name, tg.grantee, tg.is_grantable;

File.separator vs FileSystem.getSeparator() vs System.getProperty("file.separator")?

System.getProperties() can be overridden by calls to System.setProperty(String key, String value) or with command line parameters -Dfile.separator=/

File.separator gets the separator for the default filesystem.

FileSystems.getDefault() gets you the default filesystem.

FileSystem.getSeparator() gets you the separator character for the filesystem. Note that as an instance method you can use this to pass different filesystems to your code other than the default, in cases where you need your code to operate on multiple filesystems in the one JVM.

Can I use wget to check , but not download

If you want to check quietly via $? without the hassle of grep'ing wget's output you can use:

wget -q "http://blah.meh.com/my/path" -O /dev/null

Works even on URLs with just a path but has the disadvantage that something's really downloaded so this is not recommended when checking big files for existence.

How to show a running progress bar while page is loading

In this sample, I created a JavaScript progress bar (with percentage display), you can control it and hide it with JavaScript.

In this sample, the progress bar advances every 100ms. You can see it in JSFiddle

var elapsedTime = 0;
var interval = setInterval(function() {
  timer()
}, 100);

function progressbar(percent) {
  document.getElementById("prgsbarcolor").style.width = percent + '%';
  document.getElementById("prgsbartext").innerHTML = percent + '%';
}

function timer() {
  if (elapsedTime > 100) {
    document.getElementById("prgsbartext").style.color = "#FFF";
    document.getElementById("prgsbartext").innerHTML = "Completed.";
    if (elapsedTime >= 107) {
      clearInterval(interval);
      history.go(-1);
    }
  } else {
    progressbar(elapsedTime);
  }
  elapsedTime++;
}

In VBA get rid of the case sensitivity when comparing words?

There is a statement you can issue at the module level:

Option Compare Text

This makes all "text comparisons" case insensitive. This means the following code will show the message "this is true":

Option Compare Text

Sub testCase()
  If "UPPERcase" = "upperCASE" Then
    MsgBox "this is true: option Compare Text has been set!"
  End If
End Sub

See for example http://www.ozgrid.com/VBA/vba-case-sensitive.htm . I'm not sure it will completely solve the problem for all instances (such as the Application.Match function) but it will take care of all the if a=b statements. As for Application.Match - you may want to convert the arguments to either upper case or lower case using the LCase function.

ggplot2 plot area margins?

You can adjust the plot margins with plot.margin in theme() and then move your axis labels and title with the vjust argument of element_text(). For example :

library(ggplot2)
library(grid)
qplot(rnorm(100)) +
    ggtitle("Title") +
    theme(axis.title.x=element_text(vjust=-2)) +
    theme(axis.title.y=element_text(angle=90, vjust=-0.5)) +
    theme(plot.title=element_text(size=15, vjust=3)) +
    theme(plot.margin = unit(c(1,1,1,1), "cm"))

will give you something like this :

enter image description here

If you want more informations about the different theme() parameters and their arguments, you can just enter ?theme at the R prompt.

Test if remote TCP port is open from a shell script

If you're using ksh or bash they both support IO redirection to/from a socket using the /dev/tcp/IP/PORT construct. In this Korn shell example I am redirecting no-op's (:) std-in from a socket:

W$ python -m SimpleHTTPServer &
[1]     16833
Serving HTTP on 0.0.0.0 port 8000 ...
W$ : </dev/tcp/127.0.0.1/8000

The shell prints an error if the socket is not open:

W$ : </dev/tcp/127.0.0.1/8001
ksh: /dev/tcp/127.0.0.1/8001: cannot open [Connection refused]

You can therefore use this as the test in an if condition:

SERVER=127.0.0.1 PORT=8000
if (: < /dev/tcp/$SERVER/$PORT) 2>/dev/null
then
    print succeeded
else
    print failed
fi

The no-op is in a subshell so I can throw std-err away if the std-in redirection fails.

I often use /dev/tcp for checking the availability of a resource over HTTP:

W$ print arghhh > grr.html
W$ python -m SimpleHTTPServer &
[1]     16863
Serving HTTP on 0.0.0.0 port 8000 ...
W$ (print -u9 'GET /grr.html HTTP/1.0\n';cat <&9) 9<>/dev/tcp/127.0.0.1/8000
HTTP/1.0 200 OK
Server: SimpleHTTP/0.6 Python/2.6.1
Date: Thu, 14 Feb 2013 12:56:29 GMT
Content-type: text/html
Content-Length: 7
Last-Modified: Thu, 14 Feb 2013 12:55:44 GMT

arghhh
W$ 

This one-liner opens file descriptor 9 for reading from and writing to the socket, prints the HTTP GET to the socket and uses cat to read from the socket.