    var answer = Math.floor(x)

I sincerely hope this will help future searchers when googling for this common question.

    var x = parseInt(455/10);

&gt; The parseInt() function parses a string and returns an integer.
&gt; 
&gt; The radix parameter is used to specify which numeral system to be
&gt; used, for example, a radix of 16 (hexadecimal) indicates that the
&gt; number in the string should be parsed from a hexadecimal number to a
&gt; decimal number.
&gt; 
&gt; If the radix parameter is omitted, JavaScript assumes the following:
&gt; 
&gt;     If the string begins with &quot;0x&quot;, the radix is 16 (hexadecimal)
&gt;     If the string begins with &quot;0&quot;, the radix is 8 (octal). This feature is deprecated
&gt;     If the string begins with any other value, the radix is 10 (decimal)



I have the following state:

    this.setState({ selected: { id: 1, name: &#39;Foobar&#39; } });  

Then I update the state:

    this.setState({ selected: { name: &#39;Barfoo&#39; }});

Since `setState` is suppose to merge I would expect it to be:
    
    { selected: { id: 1, name: &#39;Barfoo&#39; } }; 

But instead it eats the id and the state is:

    { selected: { name: &#39;Barfoo&#39; } }; 

Is this expected behavior and what&#39;s the solution to update only one property of a nested state object?


this.setState isn&#39;t merging states as I would expect

I have a example angularJS

    &lt;div ng-controller=&quot;testCtrl&quot;&gt;

    &lt;test color1=&quot;color1&quot; updateFn=&quot;updateFn()&quot;&gt;&lt;/test&gt;
    &lt;/div&gt;
     &lt;script&gt;
      angular.module(&#39;dr&#39;, [])
	.controller(&quot;testCtrl&quot;, function($scope) {
		$scope.color1 = &quot;color&quot;;
		$scope.updateFn = function() {
			alert(&#39;123&#39;);
		}
	})
	.directive(&#39;test&#39;, function() {
		return {
			restrict: &#39;E&#39;,
			scope: {color1: &#39;=&#39;,
					updateFn: &#39;&amp;&#39;},
			template: &quot;&lt;button ng-click=&#39;updateFn()&#39;&gt;Click&lt;/button&gt;&quot;,
			replace: true,
			link: function(scope, elm, attrs) {	
			}
		}
	});

    &lt;/script&gt;
    &lt;/body&gt;
 
    &lt;/html&gt;

I want when I click button, the alert box will appear, but nothing show.

Can anyone help me?


AngularJS - pass function to directive

Is there any function in Javascript that lets you do integer division, I mean getting division answer in int, not in floating point number.

    var x = 455/10;
    // Now x is 45.5
    // Expected x to be 45

But I want x to be 45. I am trying to eliminate last digit from the number.

How to do integer division in javascript (Getting division answer in int not float)?

Is there any function in Javascript that lets you do integer division, I mean getting division answer in int, not in floating point number.
<pre><code class="hljs language-csharp">var x = 455/10;
// Now x is 45.5
// Expected x to be 45
</code></pre>
But I want x to be 45. I am trying to eliminate last digit from the number.

I have a service called &quot;localhost:3000/returnStat&quot; that should take a file path as parameter. For example &#39;/BackupFolder/toto/tata/titi/myfile.txt&#39;.

How can I test this service on my browser?
How can I format this request using Express for instance?


    exports.returnStat = function(req, res) {

	var fs = require(&#39;fs&#39;);
	var neededstats = [];
	var p = __dirname + &#39;/&#39; + req.params.filepath;

	fs.stat(p, function(err, stats) {
		if (err) {
			throw err;
		}
		neededstats.push(stats.mtime);
		neededstats.push(stats.size);
		res.send(neededstats);
	});
    };

Node.js: get path from the request

Following this question here :

&gt; https://stackoverflow.com/questions/8180744/using-the-checked-binding-in-knockout-with-a-list-of-checkboxes-checks-all-the-c

I&#39;ve created some checkboxes using knockout that allow selection from an array.
working fiddle taken from above post:

&gt; http://jsfiddle.net/NsCXJ/

Is there a simple way of creating an array of just the fruit&#39;s ID&#39;s?

I&#39;m more at home with C# where I would do something along the lines of `selectedFruits.select(fruit=&gt;fruit.id);`

Is there some method/ready made function for doing something similar with javascript/jquery?  Or would the simplest option be to loop through the list and create a second array?
I intend to post the array back to the server in JSON so am trying to minimize the data sent.

Javascript Equivalent to C# LINQ Select

I have an object that could be any number of levels deep and could have any existing properties.
For example:

&lt;!-- language: lang-js --&gt;

    var obj = {
        db: {
            mongodb: {
                host: &#39;localhost&#39;
            }
        }
    };

On that I would like to set (or overwrite) properties like so:

&lt;!-- language: lang-js --&gt;

    set(&#39;db.mongodb.user&#39;, &#39;root&#39;);
    // or:
    set(&#39;foo.bar&#39;, &#39;baz&#39;);

Where the property string can have any depth, and the value can be any type/thing.  
Objects and arrays as values don&#39;t need to be merged, should the property key already exist.

Previous example would produce following object:

&lt;!-- language: lang-js --&gt;

    var obj = {
        db: {
            mongodb: {
                host: &#39;localhost&#39;,
                user: &#39;root&#39;
            }
        },
        foo: {
            bar: baz
        }
    };

How can I realize such a function?

Dynamically set property of nested object

I have various javascripts that are necessary plugins in one of my WordPress domains, and I know where in the php file it&#39;s called from.

I&#39;m taking every measure I can take to **speed up page loading times**, and every speed tester on the web says to defer javascripts if possible.

I have read about the **defer=&#39;defer&#39;** and the **async** functions in javascript and I think one of these will accomplish what I&#39;m trying to accomplish.  But I&#39;m not understanding how I&#39;d do so in a php file.

For instance, here is a snippet from one particular plugin&#39;s php file where the javascript file is being called:

	function add_dcsnt_scripts() {

		wp_enqueue_script( &#39;jquery&#39; );
		wp_enqueue_script( &#39;dcsnt&#39;, dc_jqsocialtabs::get_plugin_directory() . &#39;/js/jquery.social.media.tabs.1.7.1.min.js&#39; );

	}

I&#39;ve read that it&#39;s best to do something like this for faster page loading times:

    &lt;script defer async src=&quot;...&quot;&gt;&lt;/script&gt;

But I don&#39;t know how to accomplish that within a php file.  I want to do this with all of my javascript files.

**How would I accomplish deferring or asyncing this javascript snippet to is loads last and speeds up page load times**?  What would be the ideal way to increase page load times across all browsers?  Thanks for any guidance anybody can offer!

How do I defer or async this WordPress javascript snippet to load lastly for faster page load times?

In Python 3 vs Python 2.6, I&#39;ve noticed that I can divide two integers and get a float. How do you get the Python&amp;nbsp;2.6 behaviour back?

Is there a different method to get int/int = int?






Python 3 integer division

How can I divide two numbers in Python 2.7 and get the result with decimals?

I don&#39;t get it why there is difference:

in Python 3: 

    &gt;&gt;&gt; 20/15
    1.3333333333333333

in Python 2:

    &gt;&gt;&gt; 20/15
    1

Isn&#39;t this a modulo actually?

Division in Python 2.7. and 3.3

How can I ignore `ZeroDivisionError` and make `n / 0 == 0`?

Make division by zero equal to zero

I have a table `software` and columns in it as `dev_cost`, `sell_cost`. If `dev_cost` is 16000 and `sell_cost` is 7500.

How do I find the quantity of software to be sold in order to recover the `dev_cost`? 

I have queried as below:

    select dev_cost / sell_cost from software ;

It is returning 2 as the answer. But we need to get 3, right?

What would be the query for that? Thanks in advance.

Division ( / ) not giving my answer in postgresql

Problem
==============
Say you have two lists `A = [a_1, a_2, ..., a_n]` and `B = [b_1, b_2, ..., b_n]` of integers. We say `A` is **potentially-divisible** by `B` if there is a permutation of `B` that makes `a_i` divisible by `b_i` for all `i`. The problem is then: is it possible to reorder (i.e. permute) `B` so that `a_i` is divisible by `b_i` for all `i`?
For example, if you have

    A = [6, 12, 8]
    B = [3, 4, 6]

Then the answer would be `True`, as `B` can be reordered to be `B = [3, 6, 4]` and then we would have that `a_1 / b_1 = 2 `, `a_2 / b_2 = 2 `, and `a_3 / b_3 = 2 `, all of which are integers, so `A` is potentially-divisible by `B`.

As an example which should output `False`, we could have:

    A = [10, 12, 6, 5, 21, 25]
    B = [2, 7, 5, 3, 12, 3]

The reason this is `False` is that we can&#39;t reorder `B` as 25 and 5 are in `A`, but the only divisor in `B` would be 5, so one would be left out.

Approach
==============

Obviously the straightforward approach would be to get all the permutations of `B` and see if one would satisfy **potential-divisibility**, something along the lines of:

    import itertools
    def is_potentially_divisible(A, B):
      perms = itertools.permutations(B)
      divisible = lambda ls: all( x % y == 0 for x, y in zip(A, ls))
      return any(divisible(perm) for perm in perms)

Question
==============
What is the fastest way to know if a list is potentially-divisible by another list? Any thoughts? I was thinking if there&#39;s is a clever way to do this with **primes**, but I couldn&#39;t come up with a solution.

Much appreciated!


----------

*Edit*: It&#39;s probably irrelevant to most of you, but for the sake of completeness, I&#39;ll explain my motivation. In Group Theory there is a conjecture on finite simple groups on whether or not there is a bijection from irreducible characters and conjugacy classes of the group such that every character degree divides the corresponding class size. For example, for *U6(4)* [here are what `A` and `B` would look like.][1] Pretty big lists, mind you!


  [1]: https://gist.github.com/nachonavarro/cffc80ee2cf27cf6535d29b2dbfc9913

Is a list (potentially) divisible by another?

I am trying to perform a simple division in Go.

    fmt.Println(3/10)

This prints 0 instead of 0.3. This is kind of weird. Could someone please share what is the reason behind this? i want to perform different arithmetic operations in Go.

Thanks

How to perform division in Go

I&#39;ve been reading about `div` and `mul` assembly operations, and I decided to see them in action by writing a simple program in C:

### File division.c

    #include &lt;stdlib.h&gt;
    #include &lt;stdio.h&gt;

    int main()
    {
        size_t i = 9;
        size_t j = i / 5;
        printf(&quot;%zu\n&quot;,j);
        return 0;
    }

And then generating assembly language code with:

    gcc -S division.c -O0 -masm=intel

But looking at generated `division.s` file, it doesn&#39;t contain any div operations! Instead, it does some kind of black magic with bit shifting and magic numbers. Here&#39;s a code snippet that computes `i/5`:

    mov     rax, QWORD PTR [rbp-16]   ; Move i (=9) to RAX
    movabs  rdx, -3689348814741910323 ; Move some magic number to RDX (?)
    mul     rdx                       ; Multiply 9 by magic number
    mov     rax, rdx                  ; Take only the upper 64 bits of the result
    shr     rax, 2                    ; Shift these bits 2 places to the right (?)
    mov     QWORD PTR [rbp-8], rax    ; Magically, RAX contains 9/5=1 now, 
                                      ; so we can assign it to j

What&#39;s going on here? Why doesn&#39;t GCC use div at all? How does it generate this magic number and why does everything work?


Why does GCC use multiplication by a strange number in implementing integer division?

I have recently noticed that [`int()`][1] rounds a float towards 0, while [integer division][2] rounds a float towards its floor.

for instance:
```
-7 // 2 == -4
int(-7/2) == -3
```

I have read the documentation which specifies:
&gt; class int(x, base=10)
&gt;
&gt;    Return an integer object constructed from a number or string x, or return 0 if no arguments are &gt;given. If x is a number, return `x.__int__()`. For floating point numbers, **this truncates towards zero.**

and:
&gt;floor division
&gt;
&gt;Mathematical division that rounds **down to nearest integer.** The floor division operator is `//`. For example, the expression `11 // 4` evaluates to 2 in contrast to the `2.75` returned by float true division. Note that `(-11) // 4` is `-3` because that is `-2.75` rounded downward. See [PEP 238][3].

But it seems illogical for me that 2 similar operations (float division to integer) should return different results.

Is there any motivation for the differences between the functions?


  [1]: https://docs.python.org/3/library/functions.html#int
  [2]: https://docs.python.org/3/glossary.html#term-floor-division
  [3]: https://www.python.org/dev/peps/pep-0238

What is the reason for difference between integer division and float to int conversion in python?

I know Python `//` rounds towards negative infinity and in C++ `/` is truncating, rounding towards 0.

And here&#39;s what I know so far:

```lang-none
               |remainder|
-12 / 10  = -1,   - 2      // C++
-12 // 10 = -2,   + 8      # Python

12 / -10  = -1,     2      // C++
12 // -10 = -2,   - 8      # Python

12 / 10  = 1,      2       // Both
12 // 10 = 1,      2

-12 / -10 = 1,    - 2      // Both
          = 2,    + 8

C++:
1. m%(-n) == m%n
2. -m%n == -(m%n)
3. (m/n)*n + m%n == m

Python:
1. m%(-n) == -8 == -(-m%n)
2. (m//n)*n + m%n == m
```

But why Python `//` choose to round towards negative infinity? I didn&#39;t find any resources explain that, but only find and hear people say vaguely: *&quot;for mathematics reasons&quot;*.

For example, in *https://stackoverflow.com/questions/22030342/why-is-1-2-evaluated-to-0-in-c-but-1-in-python*:

&gt; People dealing with these things in the abstract tend to feel that
&gt; rounding toward negative infinity makes more sense (**that means it&#39;s
&gt; compatible with the modulo function as defined in mathematics, rather
&gt; than % having a somewhat funny meaning**).

But I don&#39;t see C++ &#39;s `/` not being compatible with the modulo function. In C++, `(m/n)*n + m%n == m` also applies.

So what&#39;s the (mathematical) reason behind Python choosing rounding towards negative infinity?


----------

See also [Guido van Rossum&#39;s old blog post on the topic][1].

  [1]: http://python-history.blogspot.com/2010/08/why-pythons-integer-division-floors.html









Content Type	Original Author	Original Content on Stackoverflow
Question	Nakib	View Question on Stackoverflow
Solution 1 - Javascript	Neeraj	View Answer on Stackoverflow
Solution 2 - Javascript	ST3	View Answer on Stackoverflow

How to do integer division in javascript (Getting division answer in int not float)?

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Solution 2 - Javascript

AngularJS - pass function to directive

this.setState isn't merging states as I would expect

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