Python | Add similar value multiple times in list
Adding a single value in list is quite generic and easy. But to add that value more than one time, generally, a loop is used to execute this task. Having shorter tricks to perform this can be handy. Let’s discuss certain ways in which this can be done.
Method #1 : Using * operator
We can employ * operator to multiply the occurrence of the particular value and hence can be used to perform this task of adding value multiple times in just a single line and makes it readable.
# Python3 code to demonstrate # to add multiple similar values# using * operator # using * operator to add multiple values# adds 3, 50 times.res = [3] * 50 # printing resultprint ("The filtered list is : " + str(res)) |
Output :
The filtered list is : [3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]
Method #2 : Using extend() + list comprehension
extend function is used to perform the list append and list comprehension part is responsible for performing the task of repetition of elements desired number of times.
# Python3 code to demonstrate # to add multiple similar values# using extend() + list comprehension # using extend() + list comprehension to add multiple values# adds 3, 50 times.res = []res.extend([3 for i in range(50)]) # printing resultprint ("The filtered list is : " + str(res)) |
Output :
The filtered list is : [3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]
Method #3 : Using extend() + itertools.repeat()
This is similar to the above method, the task of extend() is similar, but repeat() performs the task list comprehension performed of iteration N no. of times desired.
# Python3 code to demonstrate # to add multiple similar values# using extend() + itertools.repeat()from itertools import repeat # using extend() + itertools.repeat() to add multiple values# adds 3, 50 times.res = []res.extend(repeat(3, 50)) # printing resultprint ("The filtered list is : " + str(res)) |
Output :
The filtered list is : [3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]
.png)