Number of different letters X36667

Statement

A code to compute the number of different letters a word has is desired. Write a function @num_dif_letters_list(f)@ that provided a list of words $f$ returns a list of numbers. Each number in the result list has to be the number of different letters of the corresponding word in $f$ . All words in $f$ consists of lowercase letters.

Sample session

>>> num_dif_letters_list(['alea', 'iacta', 'est'])
[3, 4, 3]
>>> num_dif_letters_list(['', 'z', 'zz', 'zzz', 'zzzz'])
[0, 1, 1, 1, 1]
>>> num_dif_letters_list([])
[]
>>> num_dif_letters_list(['atalaya', 'orinoco', 'pasas', 'elixir'])
[4, 5, 3, 5]

Information

Author: ProAl
Language: English
Official solutions: Python
User solutions: Python