Question

How can i parse a long string that come from a .txt file every

2 characters

?

Answer 1

You can just zip two strings, with a gap of one offset

>>> data = "foobar"
>>> map(''.join, zip(data, data[1:]))
['fo', 'oo', 'ob', 'ba', 'ar']

And a similar solution using itertools.izip

>>> from itertools import izip
>>> map(''.join, izip(data, data[1:]))
['fo', 'oo', 'ob', 'ba', 'ar']

If you are using Py3.X, convert the map to LC

>>> [''.join(e) for e in  izip(data, data[1:])]
['fo', 'oo', 'ob', 'ba', 'ar']

As @Duncan mentioned, the sub-strings would overlap. In case if you want non-overlapping substrings, either refer @Duncan’s answer, or @Duncan’s comment or the grouper recipe

>>> [''.join(e) for e in list(izip_longest(*[iter(data)] * 2,fillvalue=''))]
['fo', 'ob', 'ar']

You can easily join the resultant list to a string

>>> ' '.join(''.join(e) for e in  izip(data, data[1:]))
'fo oo ob ba ar'