Iterate over a dictionary in Python
Dictionary in Python is an unordered collection of data values, used to store data values like a map, which unlike other Data Types that hold only single value as an element, Dictionary holds key:value pair.
There are multiple ways to iterate over a dictionary in Python.
- Iterate through all keys
- Iterate through all values
- Iterate through all key, value pairs
Iterate through all keys:
The order of states in the below code will change every time because the dictionary doesn’t store keys in a particular order.
# Python3 code to iterate through all keys in a dictionary statesAndCapitals = { 'Gujarat' : 'Gandhinagar', 'Maharashtra' : 'Mumbai', 'Rajasthan' : 'Jaipur', 'Bihar' : 'Patna' } print('List Of given states:\n') # Iterating over keysfor state in statesAndCapitals: print(state) |
Output:
List Of given states: Rajasthan Bihar Maharashtra Gujarat
In order to maintain the order of keys and values in a dictionary, use OrderedDict.
# Python3 code to iterate through all keys # in a dictionary in a specific order from collections import OrderedDict statesAndCapitals = OrderedDict([ ('Gujarat', 'Gandhinagar'), ('Maharashtra', 'Mumbai'), ('Rajasthan', 'Jaipur'), ('Bihar', 'Patna') ]) print('List Of given states:\n') # Iterating over keysfor state in statesAndCapitals: print(state) |
Output:
List Of given states: Gujarat Maharashtra Rajasthan Bihar
Above dictionary is an OrderedDict as the keys and values are stored in the order in which they were defined in the dictionary. Hence the above method should be used when we want to maintain the order of (key, value) stored in the dictionary.
Iterate through all values:
Again, in this case, the order in which the capitals are printed in the below code will change every time because the dictionary doesn’t store them in a particular order.
# Python3 code to iterate through all values in a dictionary statesAndCapitals = { 'Gujarat' : 'Gandhinagar', 'Maharashtra' : 'Mumbai', 'Rajasthan' : 'Jaipur', 'Bihar' : 'Patna' } print('List Of given capitals:\n') # Iterating over valuesfor capital in statesAndCapitals.values(): print(capital) |
Output:
List Of given capitals: Gandhinagar Jaipur Mumbai Patna
Iterate through all key, value pairs:
# Python3 code to iterate through all key, value # pairs in a dictionary statesAndCapitals = { 'Gujarat' : 'Gandhinagar', 'Maharashtra' : 'Mumbai', 'Rajasthan' : 'Jaipur', 'Bihar' : 'Patna' } print('List Of given states and their capitals:\n') # Iterating over valuesfor state, capital in statesAndCapitals.items(): print(state, ":", capital) |
Output:
List Of given states and their capitals: Bihar : Patna Gujarat : Gandhinagar Rajasthan : Jaipur Maharashtra : Mumbai
Last Updated on October 28, 2021 by admin