3.4.2 Looping over dictionaries

There are mainly three ways to loop over dictionaries:

• By keys:

for key in truck_wheel.keys():
    print(key) # prints (in any order) 'Ix', 'Iy', 'name',...

or equivalently:

for key in truck_wheel:
    print(key) # prints (in any order) 'Ix', 'Iy', 'name',...

• By value:

for value in truck_wheel.values():
    print(value) 
    # prints (in any order) 1.0, 20.0, 17.0, 'wheel', ...

• By item, that is, key/value pairs:

for item in truck_wheel.items():
    print(item) 
    # prints (in any order) ('Iy', 1.0), ('Ix, 20.0),...

Please consult Section 14.4: Shelves for a special dictionary object for file access.