[PyOpenGL-Users] stackoverflow: fastest way to build a c array from a list of tuples of floats?

[Jonathan H. <ta...@ta...>]

There's an interesting question on StackOverflow today that I suspect a 
lot of people would like to see an optimal answer to:

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What is the fastest way in python to build a c array from a list of 
tuples of floats? The context: my Python code pass arrays of 2D vertices 
to OpenGL.

I tested 2 approaches, one with ctypes, the other with struct, the 
latter being more than twice faster.

from random import random
points = [(random(), random()) for _ in xrange(1000)]

from ctypes import c_float
def array_ctypes(points):
     n = len(points)
     return n, (c_float*(2*n))(*[u for point in points for u in point])

from struct import pack
def array_struct(points):
     n = len(points)
     return n, pack("f"*2*n, *[u for point in points for u in point])

Any other alternatives?
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http://stackoverflow.com/q/4156872/10176


He's already chosen one answer, but I think that was premature, and some 
of you folks might have substantially better ideas. I'm thinking of a 
fully static-typed Cython function, but I apparently lack the smarts to 
get it working over breakfast, and now I have to go to work.

	Jonathan

-- 
Jonathan Hartley      Made of meat.      http://tartley.com
ta...@ta...   +44 7737 062 225   twitter/skype: tartley