Raymond Hettinger wrote:
> [Steven Bethard]
>
>>>I have a list of strings that looks something like:
>>>lst = ['0', '0', '(*)', 'O', '(*', '*', '(*', '*))', '((*', '*)', '*)']
>
> . . .
>
>>>I want the indices:
>>>(2, 2), (4, 7), (6, 7), (8, 9) and (8, 10)
>
> opener_stack = []
> for i, elem in enumerate(lst):
> for c in elem:
> if c == '(':
> opener_stack.append(i)
> elif c == ')':
> print opener_stack.pop(), i
>
Thanks Raymond, this is definitely an elegant solution. It was also easy
to add all the error checking I needed into this one. For the curious,
my final solution looks something like:
def indices(lst):
stack = []
for i, elem in enumerate(lst):
for c in elem:
if c == '(':
stack.append(i)
elif c == ')' and not stack:
raise Exception('")" at %i without "("' % i)
elif c == ')':
yield stack.pop(), i
elif c == 'O' and stack:
raise Exception('"O" at %i after "(" at %i' %
(i, stack[-1]))
elif c == '*' and not stack:
raise Exception('"*" at %i without "("' % i)
if stack:
raise Exception('"(" at %r without ")"' % stack)
Thanks again!
STeVe
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