Splitting a string by list of indices
Here is a short solution with heavy usage of the itertools module. The tee
function is used to iterate pairwise over the indices. See the Recipe section in the module for more help.
>>> from itertools import tee, izip_longest
>>> s = 'long string that I want to split up'
>>> indices = [0,5,12,17]
>>> start, end = tee(indices)
>>> next(end)
0
>>> [s[i:j] for i,j in izip_longest(start, end)]
['long ', 'string ', 'that ', 'I want to split up']
Edit: This is a version that does not copy the indices list, so it should be faster.
You can write a generator if you don't want to make any modifications to the list of indices:
>>> def split_by_idx(S, list_of_indices):
... left, right = 0, list_of_indices[0]
... yield S[left:right]
... left = right
... for right in list_of_indices[1:]:
... yield S[left:right]
... left = right
... yield S[left:]
...
>>>
>>>
>>> s = 'long string that I want to split up'
>>> indices = [5,12,17]
>>> [i for i in split_by_idx(s, indices)]
['long ', 'string ', 'that ', 'I want to split up']
s = 'long string that I want to split up'
indices = [0,5,12,17]
parts = [s[i:j] for i,j in zip(indices, indices[1:]+[None])]
returns
['long ', 'string ', 'that ', 'I want to split up']
which you can print using:
print '\n'.join(parts)
Another possibility (without copying indices
) would be:
s = 'long string that I want to split up'
indices = [0,5,12,17]
indices.append(None)
parts = [s[indices[i]:indices[i+1]] for i in xrange(len(indices)-1)]