Python by Swaroop C H - HTML preview

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Using List Comprehensions

Example 15.1. Using List Comprehensions

#!/usr/bin/python
# Filename: list_comprehension.py

listone = [2, 3, 4]
listtwo = [2*i for i in listone if i > 2] print listtwo

Output

$ python list_comprehension.py [6, 8]

How It Works

Here, we derive a new list by specifying the manipulation to be done ( 2*i) when some condition is satisfied (if i > 2). Note that the original list remains unmodified. Many a time, we use loops to process each element of a list, the same can be achieved using list comprehensions in a more precise, compact and explicit manner.