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Exercise

Dictionary comprehension

A dictionary comprehension is very similar to a list comprehension. The difference is that the final result is a dictionary instead of a list. Recall that each element in a dictionary has 2 parts, a key and a value, which is separated by a colon.

The following dictionary comprehension squares all values in a list: 

x = [['a', 1], ['b', 2], ['c', 3], ['d', 4]]
print({key:(value**2) for (key, value) in x})

{'a': 1, 'b': 4, 'c': 9, 'd': 16}

Note:

  • When you print a dictionary, the insertion-order of elements is preserved.
  • Dictionary comprehensions are wrapped inside { }.

Instructions

100 XP
  • Inspect the contents of the 2D list twitter_followers in the shell.
  • Write a dict comprehension where the key is first element of the sub-list, and the value is the second: tf_dict.
  • Print tf_dict.