permutations of varying length

[Gribouillis]

These kinds of permutations are called «Arrangements» in classical mathematical literature (although there may be more modern terms to refer to them) See the paragraph about k-permutations of n here https://en.wikipedia.org/wiki/Permutatio...tions_of_n (note that these are only the 'restricted partial premutations' in https://en.wikipedia.org/wiki/Partial_pe...rmutations)

The following piece of code should do the trick

s = "abcde"                               
n = len(s)                                 
seq = (a for i in range(1, n+1) for c in itt.combinations(s, i) for a in itt.permutations(c, i))                                       
                                           
for x in seq:                             
    print(x)