List Comprehension 6 dec 2017

List Comprehension 6 dec 2017

Basic Examples:
1.{ x^2: x is a natural number less than 10 }
[x*2 for x in range(0,10)]
2.{ x: x is a whole number less than 20, x is even }
[x for x in range(0,20) if x%2 == 0]
3.{ x: x is an alphabet in word ‘MATHEMATICS’, x is a vowel }
[x for x in "MATHEMATICS" x not in "AEIOU"]
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The same gets implemented in a simple LC construct in a single line as:
 [ output_expression() for(set of values to iterate) if(conditional filtering) ]
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 Things to keep in mind:

LC will always return a result, whether you use the result or nor.
The iteration and conditional expressions can be nested with multiple instances.
Even the overall LC can be nested inside another LC.
Multiple variables can be iterated and manipulated at same time.
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 Example 3: Dictionary Comprehension
Aim: Take two list of same length as input and return a dictionary with one as keys and other as values.

{list1[i] : list2[i] for i in range(len(list1))}
Output {'a1': 2, 'a0': 1, 'a3': 3}

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