Python

 sentence = 'The quick brown fox jumps over the lazy dog.'
characters = {}
for character in sentence:
    characters[character] = characters.get(character, 0) + 1

#-----------------------------------------------------------

# Afficher les variables d'environnement 

import os
for a in os.environ:
    print('Var: ', a, 'Value: ', os.getenv(a))
print("all done")

#-----------------------------------------------------------