List comprehension python

List comprehension is a technique to create new list in a very simple and effective way. Which using expression, conditions and iterable objects to generate new resulting list. Syntax of this as follows.

list = [expression for item in iterable if condition]

Here iterable can be (range,string,set,tuple and list) etc. Condition is optional, and this are returns a new list.

Example 1

# Example 1
num = [x for x in range(1,6)]
# Display result list
print(num)

[1, 2, 3, 4, 5]

Example 2

# Example 2
num = [1, 2, 3, 4, 5, 6, 10]

# Collecting odd element from given number
# here condition is if (x % 2 == 0)
result = [x for x in num if x % 2 == 0]

# Display result list
print(result)

[2, 4, 6, 10]

Example 3

# Example 3
result = [c for c in "Like"]
# Display result list
print(result)

['L', 'i', 'k', 'e']

Example 4

# Example 4
matrix = [[1,2,3],[4,5,6],[7,8,9]]
result = [[col[x] for col in matrix] for x in range(len(matrix))]
# Display result list
print(result)

[[1, 4, 7], [2, 5, 8], [3, 6, 9]]