Idiomatic way of repeating items in a sequence.

[sismex01 at hebmex.com]

> From: anlri at wmdata.com [mailto:anlri at wmdata.com] 
> Sent: Lunes, 30 de Junio de 2003 06:26 a.m.
> 
> I need to repeat each item in a list n times, like this function does:
> 
>   def repeatitems(sequence, repetitions):
>       newlist = []
>       for item in sequence:
>           for i in range(repetitions):
>               newlist.append(item)
>       return newlist
> 
> Output:
> 
>   >>> repeatitems(['a', 'b', 'c'], 3)
>   ['a', 'a', 'a', 'b', 'b', 'b', 'c', 'c', 'c']
> 
> Clear and simple. But i wonder if there is a more idiomatic 
> way. Surely not this:
> 
>   def repeatitems(sequence, repetitions):
>       return reduce(lambda l, i: l + i, [[item] * repetitions 
> for item in sequence])
>

eek, lambdas.  Something like this comes to mind:

def repeatitems(L, n):
    out = []
    for i in L:
        out.extend([i]*n)
    return out

Sometimes a for loop is better :-)

-gustavo

pd: I haven't tested it, so caveat emptor!
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