Programme chap3_syntaxe_2154_.py

# coding: latin-1
li = ["un", "deux", "un", "trois"]
d  = { }
for l in li :
    if l not in d : d [l] = 1
    else : d [l] += 1
print d   # affiche {'un': 2, 'trois': 1, 'deux': 1}