Is there a Python module that already does this?

Brian Kelley bkelley at wi.mit.edu
Wed Feb 6 16:31:11 CET 2002


MDK wrote:

>I need to convert a list into a list of characters.
>
>For example:
>
>("cat",5,['dog',[3,3,1]],"zoo")
>
>Would become:
>
>('c','a','t',5,'d','o','g',3,3,1,'z','o','o')
>
>Any information would be appreciated.
>
>Thanks
>
>
It's an interesting problem.  A particularly slow solution follows. 
 Interestingly, it purposely uses the maximum recursion error to keep 
the code simpler and not have to do any type checking.  Given this fact, 
it's faster than I expected :)

def _delve(s, target):
    """(s, target)->recursively split elements of s and
    append each element to the target list
    Warning, purposely uses maximum recursions
    for simplicity!"""
    try:
        for data in s:
            _delve(data, target)
    except TypeError:
        target.append(s)
    except RuntimeError:
        # catch maximum recursion errors
        # this occurs when trying to split a character
        # string like "s"
        target.append(s)

def delve(input):
    """(input)->recursively split input
    i.e.
    ('cat', 5, ['dog', [3, 3, 1]], 'zoo')
    will reult in
    ('c', 'a', 't', 5, 'd', 'o', 'g', 3, 3, 1, 'z', 'o', 'o')

    warning, purposely uses maximum recursions!
    """   
    target = []
    _delve(data, target)
    return tuple(target)

print delve(("cat",5,['dog',[3,3,1]],"zoo"))

Brian Kelley
Whitehead Institute for Biomedical Research




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