Sure!  The code&#39;s [here][1], starting with function `islt` and proceeding for QUITE a while;-). As Chris&#39;s comment suggests, it&#39;s C code.  You&#39;ll also want to read [this][2] text file for a textual explanation, results, etc etc.

If you prefer reading Java code than C code, you could look at Joshua Bloch&#39;s implementation of timsort in and for Java (Joshua&#39;s also the guy who implemented, in 1997, the modified mergesort that&#39;s still used in Java, and one can hope that Java will eventually switch to his recent port of timsort).

Some explanation of the Java port of timsort is [here][3], the diff is [here][4] (with pointers to all needed files), the key file is [here][5] -- FWIW, while I&#39;m a better C programmer than Java programmer, in this case I find Joshua&#39;s Java code more readable overall than Tim&#39;s C code;-).


  [1]: https://github.com/python/cpython/blob/master/Objects/listobject.c
  [2]: https://github.com/python/cpython/blob/master/Objects/listsort.txt
  [3]: http://bugs.sun.com/bugdatabase/view%5Fbug.do?bug%5Fid=6804124
  [4]: http://hg.openjdk.java.net/jdk7/tl/jdk/rev/bfd7abda8f79
  [5]: http://hg.openjdk.java.net/jdk7/tl/jdk/file/bfd7abda8f79/src/share/classes/java/util/TimSort.java

I just wanted to supply a very helpful link that I missed in Alex&#39;s otherwise comprehensive answer: [A high-level explanation of Python&#39;s timsort][1] (with graph visualizations!).

(Yes, the algorithm is basically known as [Timsort][2] now)


  [1]: http://corte.si/posts/code/timsort/index.html
  [2]: http://en.wikipedia.org/wiki/Timsort

In early python-versions, the sort function implemented a modified version of quicksort.
However, it was deemed unstable and as of 2.3 they switched to using an adaptive mergesort algorithm.

I have a static javascript function that can take 1, 2 or 3 parameters:

    function getData(id, parameters, callback) //parameters (associative array) and callback (function) are optional

I know I can always test if a given parameter is undefined, but how would I know if what was passed was the parameter or the callback?

What&#39;s the best way of doing this?


----------

Examples of what could be passed in:

1:

    getData(&#39;offers&#39;);

2:

    var array = new Array();
    array[&#39;type&#39;]=&#39;lalal&#39;;
    getData(&#39;offers&#39;,array);

3:

    var foo = function (){...}
    getData(&#39;offers&#39;,foo);

4:

    getData(&#39;offers&#39;,array,foo);

Handling optional parameters in javascript

Does Enumerable.GroupBy from LINQ to Objects preserve order of elements in the groups?

Linq to Objects: does GroupBy preserve order of elements?

What algorithm is the built in `sort()` method in Python using? Is it possible to have a look at the code for that method?

About Python&#39;s built in sort() method

<p>What algorithm is the built in <code>sort()</code> method in Python using? Is it possible to have a look at the code for that method?</p>


I use the following code to stream large files from the Internet into a local file:

    fp = open(file, &#39;wb&#39;)
    req = urllib2.urlopen(url)
    for line in req:
        fp.write(line)
    fp.close()

This works but it downloads quite slowly. Is there a faster way? (The files are large so I don&#39;t want to keep them in memory.)


Stream large binary files with urllib2 to file

What is an efficient way to find the most common element in a Python list?

My list items may not be hashable so can&#39;t use a dictionary.
Also in case of draws the item with the lowest index should be returned. Example:

    &gt;&gt;&gt; most_common([&#39;duck&#39;, &#39;duck&#39;, &#39;goose&#39;])
    &#39;duck&#39;
    &gt;&gt;&gt; most_common([&#39;goose&#39;, &#39;duck&#39;, &#39;duck&#39;, &#39;goose&#39;])
    &#39;goose&#39;

Find the most common element in a list

How can I check which version of NumPy I&#39;m using?

How do I check which version of NumPy I&#39;m using?

So I&#39;m starting like Python a bit, but I&#39;m having trouble erm...running it. Lol

I&#39;m using IDLE for now, but its no use whatsoever because you can only run a couple of lines at a time.

I&#39;m also using Komodo Edit to create the actual .py files.

My question is, how can I run the .py files to test out the actual program? 

I&#39;m using Windows 7, and Komodo Edit 5 as my IDE. Pressing F5 in Komodo doesn&#39;t do anythin at all.

![alt text][1]


  [1]: http://imgur.com/x8DJK.png

How do I run a Python program?

I&#39;m new to Python and reading someone else&#39;s code:

should `urllib.urlopen()` be followed by `urllib.close()`? Otherwise, one would leak connections, correct?

should I call close() after urllib.urlopen()?

I&#39;m very curious, why stability is or is not important in sorting algorithms?


What is stability in sorting algorithms and why is it important?

I&#39;m curious if O(n log n) is the best a linked list can do.

What&#39;s the fastest algorithm for sorting a linked list?

Is there any algorithm to compute the nth fibonacci number in sub linear time?

nth fibonacci number in sublinear time

I got this problem from an interview with Microsoft.

&gt; Given an array of random integers,
&gt; write an algorithm in C that removes
&gt; duplicated numbers and return the unique numbers in the original
&gt; array.

E.g Input: `{4, 8, 4, 1, 1, 2, 9}`  Output: `{4, 8, 1, 2, 9, ?, ?}`

One caveat is that the expected algorithm should not required the array to be sorted first. And when an element has been removed, the following elements must be shifted forward as well. Anyway, value of elements at the tail of the array where elements were shifted forward are negligible. 

**Update:** The result must be returned in the original array and helper data structure (e.g. hashtable) should not be used. However, I guess order preservation is not necessary.

**Update2:** For those who wonder why these impractical constraints, this was an interview question and all these constraints are discussed during the thinking process to see how I can come up with different ideas.

Algorithm: efficient way to remove duplicate integers from an array

[Genetic algorithms][1] (GA) and [genetic programming][2] (GP) are interesting areas of research. 

I&#39;d like to know about specific problems you have solved using GA/GP and what libraries/frameworks you used if you didn&#39;t roll your own.

Questions:

* What problems have you used GA/GP to solve?
* What libraries/frameworks did you use?

I&#39;m looking for first-hand experiences, so please do not answer unless you have that.


  [1]: http://en.wikipedia.org/wiki/Genetic_algorithm
  [2]: http://en.wikipedia.org/wiki/Genetic_programming

What are good examples of genetic algorithms/genetic programming solutions?

I&#39;m trying to do my frist steps with jQuery but I have some trouble to understand how to find a list of child elements from a div parent element. I&#39;m used to work with ActionScript 2 and ActionScript 3 so i could mistake some concept, like what is the better way to randomize a sequence of div elements with jQuery!

I have this simple portion of HTML code:


    &lt;div class=&quot;band&quot;&gt;
        &lt;div class=&quot;member&quot;&gt;
            &lt;ul&gt;
                &lt;li&gt;John&lt;/li&gt;
                &lt;li&gt;Lennon&lt;/li&gt;
            &lt;/ul&gt;
        &lt;/div&gt;
        &lt;div class=&quot;member&quot;&gt;
            &lt;ul&gt;
                &lt;li&gt;Paul&lt;/li&gt;
                &lt;li&gt;McCartney&lt;/li&gt;
            &lt;/ul&gt;
        &lt;/div&gt;
        &lt;div class=&quot;member&quot;&gt;
            &lt;ul&gt;
                &lt;li&gt;George&lt;/li&gt;
                &lt;li&gt;Harrison&lt;/li&gt;
            &lt;/ul&gt;
        &lt;/div&gt;
        &lt;div class=&quot;member&quot;&gt;
            &lt;ul&gt;
                &lt;li&gt;Ringo&lt;/li&gt;
                &lt;li&gt;Starr&lt;/li&gt;
            &lt;/ul&gt;
        &lt;/div&gt;
    &lt;/div&gt;


I have attempted some way to do that like map **.member** divs in one array and then changing the sort order but without success.


    function setArrayElements (element_parent) {
        var arr = [];
        //alert (element_parent[0].innerHTML);
        for (var i = 0; i &lt; element_parent.children().length; i ++) {
            arr.push (element_parent[i].innerHTML);
        }
    }
    setArrayElements($(&quot;.band&quot;));


when i attempted to alert **element_parent[0]** i thought to get the first child of my **.member** list of divs but it isn&#39;t.

if i make an alert with **element_parent[0].innerHTML** i see that:


    &lt;div class=&quot;member&quot;&gt;
        &lt;ul&gt;
            &lt;li&gt;John&lt;/li&gt;
            &lt;li&gt;Lennon&lt;/li&gt;
        &lt;/ul&gt;
    &lt;/div&gt;
    &lt;div class=&quot;member&quot;&gt;
        &lt;ul&gt;
            &lt;li&gt;Paul&lt;/li&gt;
            &lt;li&gt;McCartney&lt;/li&gt;
        &lt;/ul&gt;
    &lt;/div&gt;
    &lt;div class=&quot;member&quot;&gt;
        &lt;ul&gt;
            &lt;li&gt;George&lt;/li&gt;
            &lt;li&gt;Harrison&lt;/li&gt;
        &lt;/ul&gt;
    &lt;/div&gt;
    &lt;div class=&quot;member&quot;&gt;
        &lt;ul&gt;
            &lt;li&gt;Ringo&lt;/li&gt;
            &lt;li&gt;Starr&lt;/li&gt;
        &lt;/ul&gt;
    &lt;/div&gt;


Why?
How can I do to get exactly one of the members like this?


    &lt;div class=&quot;member&quot;&gt;
        &lt;ul&gt;
            &lt;li&gt;Paul&lt;/li&gt;
            &lt;li&gt;McCartney&lt;/li&gt;
        &lt;/ul&gt;
    &lt;/div&gt;


I&#39;m sure this should be easy but I just don&#39;t know how
:(

please help&lt;br/&gt;
thanks&lt;br/&gt;
vittorio&lt;br/&gt;

---
EDIT:

Thanks for the fastness and this various ways to get the selected children, I&#39;ll take a note of these ways for the future!&lt;br/&gt;
I tried this methods, but it seems I couldn&#39;t get the entire div (please tell&#39;me if i mistake something, it&#39; could be too much possible!!).

I shoud get this content:

    &lt;div class=&quot;member&quot;&gt;
        &lt;ul&gt;
            &lt;li&gt;Ringo&lt;/li&gt;
            &lt;li&gt;Starr&lt;/li&gt;
        &lt;/ul&gt;
    &lt;/div&gt;

but with one of this methods like **$(&quot;div.band div.member:eq(2)&quot;)** or the other useful ways, I get this:

    alert ($(&#39;div.band div.member&#39;)[0]);
    /* result
    &lt;ul&gt;
        &lt;li&gt;Ringo&lt;/li&gt;
        &lt;li&gt;Starr&lt;/li&gt;
    &lt;/ul&gt;
    */

so is there a way to get the **.member** div container too in my node?

Randomize a sequence of div elements with jQuery

I have a vector x, that I would like to sort based on the order of values in vector y. The two vectors are not of the same length.

    x &lt;- c(2, 2, 3, 4, 1, 4, 4, 3, 3)
    y &lt;- c(4, 2, 1, 3)

The expected result would be:

    [1] 4 4 4 2 2 1 3 3 3

How do I sort one vector based on values of another

Using C++, and hopefully the standard library, I want to sort a sequence of samples in ascending order, but I also want to remember the original indexes of the new samples.

For example, I have a set, or vector, or matrix of samples `A : [5, 2, 1, 4, 3]`. I want to sort these to be  `B : [1,2,3,4,5]`, but I also want to remember the original indexes of the values, so I can get another set which would be:
 `C : [2, 1, 4, 3, 0 ]` - which corresponds to the index of each element in &#39;B&#39;, in the original &#39;A&#39;.

For example, in Matlab you can do:

     [a,b]=sort([5, 8, 7])
     a = 5 7 8
     b = 1 3 2

Can anyone see a good way to do this?

C++ sorting and keeping track of indexes

I&#39;m trying to understand the python compiler/interpreter process more clearly. Unfortunately, I have not taken a class in interpreters nor have I read much about them.

Basically, what I understand right now is that Python code from `.py` files is first compiled into python bytecode (which I assume are the `.pyc` files I see occasionally?). Next, the bytecode is compiled into machine code, a language the processor actually understands.
Pretty much, I&#39;ve read this thread https://stackoverflow.com/questions/888100/why-python-compile-the-source-to-bytecode-before-interpreting

Could somebody give me a good explanation of the whole process keeping in mind that my knowledge of compilers/interpreters is almost non-existent? Or, if that&#39;s not possible, maybe give me some resources that give quick overviews of compilers/interpreters?

Thanks

Python Compilation/Interpretation Process

Is it a linked list, an array?  I searched around and only found people guessing.  My C knowledge isn&#39;t good enough to look at the source code.

How is Python&#39;s List Implemented?

I can&#39;t really think of any reason why Python needs the `del` keyword (and most languages seem to not have a similar keyword). For instance, rather than deleting a variable, one could just assign `None` to it. And when deleting from a dictionary, a `del` method could be added.

Is there a reason to keep `del` in Python, or is it a vestige of Python&#39;s pre-garbage collection days?


When is del useful in Python?

While optimising my code I realised the following:

    &gt;&gt;&gt; from timeit import Timer as T
    &gt;&gt;&gt; T(lambda : 1234567890 / 4.0).repeat()
    [0.22256922721862793, 0.20560789108276367, 0.20530295372009277]
    &gt;&gt;&gt; from __future__ import division
    &gt;&gt;&gt; T(lambda : 1234567890 / 4).repeat()
    [0.14969301223754883, 0.14155197143554688, 0.14141488075256348]
    &gt;&gt;&gt; T(lambda : 1234567890 * 0.25).repeat()
    [0.13619112968444824, 0.1281130313873291, 0.12830305099487305]
    
and also:

    &gt;&gt;&gt; from math import sqrt
    &gt;&gt;&gt; T(lambda : sqrt(1234567890)).repeat()
    [0.2597470283508301, 0.2498021125793457, 0.24994492530822754]
    &gt;&gt;&gt; T(lambda : 1234567890 ** 0.5).repeat()
    [0.15409398078918457, 0.14059877395629883, 0.14049601554870605]

I assume it has to do with the way python is implemented in C, but I wonder if anybody would care to explain why is so?

Python: why are * and ** faster than / and sqrt()?

Is there a way to see how built in functions work in python? I don&#39;t mean just how to use them, but also how were they built, what is the code behind ***sorted*** or ***enumerate*** etc...?

Content Type	Original Author	Original Content on Stackoverflow
Question	Johannes	View Question on Stackoverflow
Solution 1 - Python	Alex Martelli	View Answer on Stackoverflow
Solution 2 - Python	u0b34a0f6ae	View Answer on Stackoverflow
Solution 3 - Python	Silfverstrom	View Answer on Stackoverflow

About Python's built in sort() method

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Solution 3 - Python

Linq to Objects: does GroupBy preserve order of elements?

Handling optional parameters in javascript

Attributions