4_unpacking.md

Unpacking

You can unpack both sequences and dictionaries into functions and assignment statements.

Sequences

print(*[1, 2, 3]) # -> 1 2 3

Dictionaries

print(*[1, 2, 3], **{'sep': ', ', 'end': '.\n'}) # -> 1, 2, 3.

Assignments

Tuple unpacking

x, y, z = 1, 2, 3
print(x, y) # -> 1 2

Rest unpacking

x, *y = 1, 2, 3
print(x, y) # -> 1 [2, 3]
print(type(y)) # -> <class 'list'>

A good rule of thumb is that when unpacking into a function, the * goes with the iterable, and when unpacking into an assignment, the * goes with the rest lvalue on the left side.