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Python Dictionary Comprehension

  • Difficulty Level : Easy
  • Last Updated : 07 Nov, 2017

Like List Comprehension, Python allows dictionary comprehensions. We can create dictionaries using simple expressions.
A dictionary comprehension takes the form {key: value for (key, value) in iterable}

Let’s see a example,lets assume we have two lists named keys and value now,

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# Python code to demonstrate dictionary 
# comprehension
# Lists to represent keys and values
keys = ['a','b','c','d','e']
values = [1,2,3,4,5]  
# but this line shows dict comprehension here  
myDict = { k:v for (k,v) in zip(keys, values)}  
# We can use below too
# myDict = dict(zip(keys, values))  
print (myDict)

Output :

{'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}

We can also make dictionary from a list using comprehension

# Python code to demonstrate dictionary 
# creation using list comprehension
myDict = {x: x**2 for x in [1,2,3,4,5]}
print (myDict)

Output :

{1: 1, 2: 4, 3: 9, 4: 16, 5: 25}

and like,

sDict = {x.upper(): x*3 for x in 'coding '}
print (sDict)

Output :

{'O': 'ooo', 'N': 'nnn', 'I': 'iii', 'C': 'ccc', 'D': 'ddd', 'G': 'ggg'}

We can use Dictionary comprehensions with if and else statements and with other expressions too. This example below maps the numbers to their cubes that are not divisible by 4:

# Python code to demonstrate dictionary 
# comprehension using if.
newdict = {x: x**3 for x in range(10) if x**3 % 4 == 0}

Output :

{0: 0, 8: 512, 2: 8, 4: 64, 6: 216}

This article is contributed by Shantanu Sharma.. If you like GeeksforGeeks and would like to contribute, you can also write an article using or mail your article to See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

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