Unpacking Python Tuples

When you create a Tuple using the (...) syntax it's called packing a Tuple.

letters = ( 'A', 'B', 'C')

The reverse is to unpack a Tuple

letters = ( 'A', 'B', 'C')
(letterA, letterB, letterC) = letters

print(letterA)      # prints 'A'
print(letterB)      # prints 'B'
print(letterC)      # prints 'C'

If we supply fewer variables in our unpack list than there are elements in the Tuple an error will be thrown.

letters = ( 'A', 'B', 'C', 'D')
(letterA, letterB, letterC) = letters

Output

ValueError: too many values to unpack (expected 3)

'Expected 3' means Python expected 3 values since there there 3 variables provided to take the values.

For this situation you can use the * operator on the last variable to instruct Python to pack all remaining items into that last variable as a List.

letters = ( 'A', 'B', 'C', 'D')
(letterA, letterB, *theRest) = letters

print(letterA)      # prints 'A'
print(letterB)      # prints 'B'
print(theRest)      # prints the List ['C', 'D']