List comprehension filtering

Use Conditional statements in list comprehension to filter out data [New list] in python. Generators and list comprehensions are more pythonic than chainable functions.

Python example filtering elements in List Comprehensions

Simple example code list comprehension with a filter or conditional statement.

even_squares = [x * x for x in range[10] if x % 2 == 0] print[even_squares]

Output:

Another Example

Extract vowels and consonants along with their indices.

a = "HELLO" l = list[a] vow = [[x, i] for i, x in enumerate[l] if x in ['A', 'E', 'I', 'O', 'U']] cons = [[x, i] for i, x in enumerate[l] if x not in ['A', 'E', 'I', 'O', 'U']] print[vow] print[cons]

Output:

[[E, 1], [O, 4]]
[[H, 0], [L, 2], [L, 3]]

Why does Python list comprehension filter have a different syntax for if-else?

Answer:

List comprehension filter without else clause

squares = [x**2 for x in range[20] if x % 2 == 0]

List comprehension filter with else clause

squares = [x**2 if x % 2 == 0 else x + 3 for x in range[20]]

The if-else clause had to be moved to the beginning of the list comprehension after the expression x**2.

The first line is to list comprehension with a filter. It builds a list of squares of x for only those xs for which x % 2 == 0.

The second line is NOT listed comprehension with a filter. Its just ordinary unfiltered list comprehension using the ternary operator

Source: stackoverflow.com

Do comment if you have any doubts and suggestions on this Python List tutorial.

Note: IDE:PyCharm2021.3 [Community Edition]

Windows 10

Python 3.10.1

AllPython Examplesare inPython3, so Maybe its different from python 2 or upgraded versions.

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