    dist = sqrt( (x2 - x1)**2 + (y2 - y1)**2 )

As others have pointed out, you can also use the equivalent built-in [`math.hypot()`][1]:

    dist = math.hypot(x2 - x1, y2 - y1)


  [1]: http://docs.python.org/2/library/math.html#math.hypot

Let&#39;s not forget math.hypot:

    dist = math.hypot(x2-x1, y2-y1)

Here&#39;s hypot as part of a snippet to compute the length of a path defined by a list of (x, y) tuples:

    from math import hypot

    pts = [
        (10,10),
        (10,11),
        (20,11),
        (20,10),
        (10,10),
        ]
    
    # Py2 syntax - no longer allowed in Py3
    # ptdiff = lambda (p1,p2): (p1[0]-p2[0], p1[1]-p2[1])
    ptdiff = lambda p1, p2: (p1[0]-p2[0], p1[1]-p2[1])
    
    diffs = (ptdiff(p1, p2) for p1, p2 in zip (pts, pts[1:]))
    path = sum(hypot(*d) for d in  diffs)
    print(path)



![enter image description here][1]
It is an implementation of Pythagorean theorem. Link: http://en.wikipedia.org/wiki/Pythagorean_theorem


  [1]: http://i.stack.imgur.com/O4MPw.png

I am not so well-versed in the C standard, so please bear with me.

I would like to know if it is guaranteed, by the standard, that `memcpy(0,0,0)` is safe.

The only restriction I could find is that if the memory regions overlap, then the behavior is undefined...

But can we consider that the memory regions overlap here ?

Is it guaranteed to be safe to perform memcpy(0,0,0)?

What is the difference between a byte array &amp; byte buffer ?   
  **Also, in what situations should one be preferred over the other?**

[my usecase is for a web application being developed in java].

When to use byte array &amp; when byte buffer?

Let&#39;s say I have x1, y1 and also x2, y2.

How can I find the distance between them?
It&#39;s a simple math function, but is there a snippet of this online?

How do I find the distance between two points?

<p>Let's say I have x1, y1 and also x2, y2.</p>
<p>How can I find the distance between them?
It's a simple math function, but is there a snippet of this online?</p>


I&#39;m simply trying to handle an uploaded file and write it in a working dir which name is the system timestamp. The problem is that I want to create that directory with full permission (**777**) but I can&#39;t! Using the following piece of code the created directory with **755** permissions.

    def handle_uploaded_file(upfile, cTimeStamp):
        target_dir = &quot;path_to_my_working_dir/tmp_files/%s&quot; % (cTimeStamp)
        os.makedirs(target_dir, mode=0777)

Permission problems when creating a dir with os.makedirs in Python

I am new to Python and am working on a Linux machine (Ubuntu 10.10). It is running python 2.6, but I&#39;d like to run 2.7 as it has features I want to use. I have been urged to not install 2.7 and set that as my default python. 

My question is, how can I install 2.7 and run it side by side with 2.6?

Python 2.7 on Ubuntu

With [tag:LINQ] I would

    var top5 = array.Take(5);

How to do this with Python?

How to take the first N items from a generator or list?

How to convert list of dict to dict. Below is the list of dict 

    data = [{&#39;name&#39;: &#39;John Doe&#39;, &#39;age&#39;: 37, &#39;sex&#39;: &#39;M&#39;},
            {&#39;name&#39;: &#39;Lisa Simpson&#39;, &#39;age&#39;: 17, &#39;sex&#39;: &#39;F&#39;},
            {&#39;name&#39;: &#39;Bill Clinton&#39;, &#39;age&#39;: 57, &#39;sex&#39;: &#39;M&#39;}]

to 

 

    data = {{&#39;name&#39;: &#39;John Doe&#39;, &#39;age&#39;: 37, &#39;sex&#39;: &#39;M&#39;},
            {&#39;name&#39;: &#39;Lisa Simpson&#39;, &#39;age&#39;: 17, &#39;sex&#39;: &#39;F&#39;},
            {&#39;name&#39;: &#39;Bill Clinton&#39;, &#39;age&#39;: 57, &#39;sex&#39;: &#39;M&#39;}}

   
   



how to convert list of dict to dict

Both list comprehensions and map-calculations should -- at least in theory -- be relatively easy to parallelize: each calculation inside a list-comprehension could be done independent of the calculation of all the other elements. For example in the expression

    [ x*x for x in range(1000) ]

each x*x-Calculation could (at least in theory) be done in parallel.

My question is: Is there any Python-Module / Python-Implementation / Python Programming-Trick to parallelize a list-comprehension calculation (in order to use all 16 / 32 / ... cores or distribute the calculation over a Computer-Grid or over a Cloud)?

How to parallelize list-comprehension calculations in Python?

I have to write a program to calculate `a**b % c` where `b` and `c` are both very large numbers. If I just use `a**b % c`, it&#39;s really slow. Then I found that the built-in function `pow()` can do this really fast by calling `pow(a, b, c)`.  
 I&#39;m curious to know how does Python implement this? Or where could I find the source code file that implement this function?

How did Python implement the built-in function pow()?

So I am trying to figure out how to take a range of numbers and scale the values down to fit a range.  The reason for wanting to do this is that I am trying to draw ellipses in a java swing jpanel.  I want the height and width of each ellipse to be in a range of say 1-30.  I have methods that find the minimum and maximum values from my data set, but I won&#39;t have the min and max until runtime.  Is there an easy way to do this?

How to scale down a range of numbers with a known min and max value

I&#39;m having a bit of a mind blank on this at the moment.
I&#39;ve got a problem where I need to calculate the position of points around a central point, assuming they&#39;re all equidistant from the center and from each other.

The number of points is variable so it&#39;s `DrawCirclePoints(int x)`
I&#39;m sure there&#39;s a simple solution, but for the life of me, I just can&#39;t see it :)

Calculating the position of points in a circle

How would I go about doing arithmetic, + - / * % !,  with arbitrarily large integers without using `java.math.BigInteger`?

For instance, the factorial of 90 returns 0 in Java.
I would like to be able to solve that.

How to handle very large numbers in Java without using java.math.BigInteger

I&#39;ve noticed recently that there are a great many algorithms out there based in part or in whole on clever uses of numbers in creative bases.  For example:

- Binomial heaps are based on binary numbers, and the more complex skew binomial heaps are based on skew binary numbers.
- Some algorithms for generating lexicographically ordered permutations are based on the factoradic number system.
- Tries can be thought of as trees that look at one digit of the string at a time, for an appropriate base.
- Huffman encoding trees are designed to have each edge in the tree encode a zero or one in some binary representation.
- Fibonacci coding is used in Fibonacci search and to invert certain types of logarithms.

My question is: **what other algorithms are out there that use a clever number system as a key step of their intuition or proof?**. I&#39;m thinking about putting together a talk on the subject, so the more examples I have to draw from, the better.

Content Type	Original Author	Original Content on Stackoverflow
Question	TIMEX	View Question on Stackoverflow
Solution 1 - Python	Mitch Wheat	View Answer on Stackoverflow
Solution 2 - Python	PaulMcG	View Answer on Stackoverflow
Solution 3 - Python	Maciej Ziarko	View Answer on Stackoverflow

How do I find the distance between two points?

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Solution 3 - Python

When to use byte array & when byte buffer?

Is it guaranteed to be safe to perform memcpy(0,0,0)?

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