Format Code Repeat Counts?

Chris Rebert clp2 at
Thu Aug 13 00:23:32 CEST 2009

On Wed, Aug 12, 2009 at 4:34 PM, jschwab<jschwab at> wrote:
> As a more concrete example, say I have several sets of letters in a
> list of strings
>     letters = ["aeiou", "hnopty", "egs", "amsp"]
> and I wanted to build a regular expression string out of them like
>     re_str <==> "[aeiou][hnopty][egs][amsp]"
> Right now, the best I've got that doesn't require an explicit string
> like "[{1}][{2}][{3}][{4}]" is
>     re_str = "".join(map(lambda x: "[{0}]".format(x), letters))
> Is there a better way?

Slightly better, by using a generator expression instead of map() and lambda:
re_str = "".join("[{0}]".format(x) for x in letters)

Though obviously MRAB's is shorter (and a good show of lateral thinking).


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