Python | Append Odd element twice
Given a list of number, the task is to create a new list from the initial list with the condition to append every odd element twice.
Below are some ways to achieve the above task.
Method #1: Using list comprehension
# Python code to create a new list from initial list # with condition to append every odd element twice. # List initialization Input = [1, 2, 3, 8, 9, 11] # Using list comprehension Output = [elem for x in Input for elem in (x, )*(x % 2 + 1)] # printing print("Initial list is:'", Input) print("New list is:", Output) |
Output:
Initial list is:' [1, 2, 3, 8, 9, 11] New list is: [1, 1, 2, 3, 3, 8, 9, 9, 11, 11]
Method #2: Using itertools
# Python code to create a new list from initial list # with condition to append every odd element twice. # Importing from itertools import chain # List initialization Input = [1, 2, 3, 8, 9, 11] # Using list comprehension and chain Output = list(chain.from_iterable([i] if i % 2 == 0 else [i]*2 for i in Input)) # printing print("Initial list is:'", Input) print("New list is:", Output) |
Output:
Initial list is:' [1, 2, 3, 8, 9, 11] New list is: [1, 1, 2, 3, 3, 8, 9, 9, 11, 11]
Method #3: Using Numpy array
# Python code to create a new list from initial list # with condition to append every odd element twice. # Importing import numpy as np # List initialization Input = [1, 2, 3, 8, 9, 11] Output = [] # Using Numpy repeat for x in Input: (Output.extend(np.repeat(x, 2, axis = 0)) if x % 2 == 1 else Output.append(x)) # printing print("Initial list is:'", Input) print("New list is:", Output) |
Output:
Initial list is:' [1, 2, 3, 8, 9, 11] New list is: [1, 1, 2, 3, 3, 8, 9, 9, 11, 11]
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