Question

I’m using Python 2.7.

Let’s say I have a list like so:

string_list = ['hello', 'apple', 'green', 'paint', 'sting']

Where each string in the list is the same length.

I want to create a generator that would be doing something like the following code:

for i in xrange(len(string_list)):
    my_gen = (ch for a_string[i] in string_list)

So the first run, my_gen would have ‘h’, ‘a’, ‘g’, ‘p’, s’. The next run it would have ‘e’, ‘p’, ‘r’, ‘a’, ‘t’.

Answer 1

Just use the built-in function zip –

like in

for letters in zip('hello', 'apple', 'green', 'paint', 'sting'):
     print letters

zip is a built-in that does just that: combine one element of each iterable in a tuple, for each iteration.

Running the above example, you have:

>>> for letters in zip('hello', 'apple', 'green', 'paint', 'sting'):
...   print letters
... 
('h', 'a', 'g', 'p', 's')
('e', 'p', 'r', 'a', 't')
('l', 'p', 'e', 'i', 'i')
('l', 'l', 'e', 'n', 'n')
('o', 'e', 'n', 't', 'g')