It doesn't work the way mrchose described.
| * 2 splits the string into tuple of 2 characters. str = 'abba' = [ ('a', 'b'), ('b', 'a') ]
| * 1 encloses each character of the string in a tuple. str = 'abba' = [ ('a'), ('b'), ('b'), ('a') ]

When I put 'group by' and 'order by' statements out of the crosstab function, and select 1 as the value of corresponded category inside crosstab, grouping and summing outside - some of my result values are less than in the results. When I do the same query but with mentioned statements inside the crosstab function I pass the tests. Am I running into some common mistake?

wite -> wRite

This is awesome!

thanks

Equivalent to iter_s = iter(s); zip(iter_s, iter_s) or zip(s[::2], s[1::2])

have wrote solution like this for python 3

have wrote solution like this for python 3

have wrote solution like this for python 3

have wrote solution like this for python 3