Remove multiple elements from a list in Python
Given a list of numbers, write a Python program to remove multiple elements from a list based on the given condition.
Example:
Input: [12, 15, 3, 10] Output: Remove = [12, 3], New_List = [15, 10] Input: [11, 5, 17, 18, 23, 50] Output: Remove = [1:5], New_list = [11, 50]
Multiple elements can be deleted from a list in Python, based on the knowledge we have about the data. Like, we just know the values to be deleted or also know the indexes of those values. Let’s see different examples based on different scenario.
Example #1: Let’s say we want to delete each element in the list which is divisible by 2 or all the even numbers.
# Python program to remove multiple # elements from a list # creating a list list1 = [11, 5, 17, 18, 23, 50] # Iterate each element in list # and add them in variale total for ele in list1: if ele % 2 == 0: list1.remove(ele) # printing modified list print("New list after removing all even numbers: ", list1) |
Output:
New list after removing all even numbers: [11, 5, 17, 23]
Example #2: Using list comprehension
Removing all even elements in a list is as good as only including all the elements which are not even( i.e. odd elements).
# Python program to remove multiple # elements from a list # creating a list list1 = [11, 5, 17, 18, 23, 50] # will create a new list, # excluding all even numbers list1 = [ elem for elem in list1 if elem % 2 != 0] print(*list1) |
Output:
11 5 17 23
Example #3: Remove adjacent elements using list slicing
Below Python code remove values from index 1 to 4.
# Python program to remove multiple # elements from a list # creating a list list1 = [11, 5, 17, 18, 23, 50] # removes elements from index 1 to 4 # i.e. 5, 17, 18, 23 will be deleted del list1[1:5] print(*list1) |
Output:
11 50
Example #4: Using list comprehension
Let’s say the elements to be deleted is known, instead of the indexes of those elements. In this case, we can directly eliminate those elements without caring about indexes which we will see in next example.
# Python program to remove multiple # elements from a list # creating a list list1 = [11, 5, 17, 18, 23, 50] # items to be removed unwanted_num = {11, 5} list1 = [ele for ele in list1 if ele not in unwanted_num] # printing modified list print("New list after removing unwanted numbers: ", list1) |
Output:
New list after removing unwanted numbers: [17, 18, 23, 50]
Example #5: When index of elements is known.
Though indexes of elements in known, deleting the elements randomly will change the values of indexes. Hence, it is always recommended to delete the largest indices first. Using this strategy, index of smaller values will not be changed. We can sort the list in reverse order and delete the elements of list in descending order.
# Python program to remove multiple # elements from a list # creating a list list1 = [11, 5, 17, 18, 23, 50] # given index of elements # removes 11, 18, 23 unwanted = [0, 3, 4] for ele in sorted(unwanted, reverse = True): del list1[ele] # printing modified list print (*list1) |
Output:
5 17 50