Beginner Python tips Day - 03 defaultdict

# Python Day-03 defaultdict

from collections import defaultdict

# You can specify the type of values the dictionary will contain
dict_of_list = defaultdict(list)

dict_of_list['languages'] = ['Python', 'JavaScript', 'Dart']

print(dict_of_list['languages'])
# Prints ['Python', 'JavaScript', 'Dart']

# when the key cannot be found empty list is returned
print(dict_of_list['frameworks'])
# Prints [] i.e empty list

dict_of_numbers = defaultdict(int)

dict_of_numbers['students'] = 10

print(dict_of_numbers['students'])
# Prints 10

print(dict_of_numbers['teachers'])
# Prints 0

# If the key isn't found return the predefined value
safe_dict = defaultdict(lambda : None)

safe_dict['hello'] = 'world'

print(safe_dict['hello'])
# Prints 'world'

print(safe_dict['world'])
# Prints None