Coding Nested Loops

Peter Otten __peter__ at web.de
Sat Sep 16 08:32:48 CEST 2006


Rich Shepard wrote:

> On Fri, 15 Sep 2006, Peter Otten wrote:
> 
>> It's not clear to me why you would use dictionaries, especially as they
>> are unordered; I used lists instead:
> 
>    ...
> 
>> Now that is a nice occasion to get acquainted with the itertools
>> module...
> 
> Peter,
> 
>    I have to study the docs to understand what's going on. But, I can see
> that this would work.

As George hinted, I went a bit over the top with my itertools example. Here
is a translation into static lists (mostly):

from itertools import izip
from random import choice

first =  ["X", "Y", "Z"]
second = ["A", "B", "C"]
third = [1.1, 2.2, 3.3, 4.4]

x, y, z = first
a, b, c = second

def random_floats(sample):
    while 1:
        yield choice(sample)

columns = [
    range(180),
    [x]*60 + [y]*60 + [z]*60,
    ([a]*13 + [b]*14 + [c]*33) * 3] + [random_floats(third)]*28

for row in izip(*columns):
    print row

Of course nested loops will work, too. Use whatever you find easiest to
maintain.

Peter




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