Python Accept list as an input from a user

As you already know using Python input() function, we can accept a string, integer, and character input from a user. Now, let see how to accept the list as an input in Python.

Goals of this article:

• Accept list as an input from a user
• Get a list of numbers or list of strings as input from a user
• Also, How to use list Comprehension and map() function to get the list as input from a user.

Get a list of numbers as input from the user

I have created two examples in python to accept a list of numbers from the user and calculate the sum of the list of numbers.

Let’s see the example.

Program 1: Get a list of numbers as input from a user and calculate the sum of it

• Use a input() function to accept the list elements from a user in the format of a string separated by space.
• Next, Use a split() function to split a string by space and added those numbers to the list.
• Next, iterate a user list using for loop and range() function.
• Convert each list element to an integer and add it to a sum variable.

input_string = input("Enter a list elements separated by space ")

print("\n")
userList = input_string.split()
print("user list is ", userList)
# Calculating the sum of input list elements
sum1 = 0
for num in userList:
    sum1 += int(num)
print("Sum = ", sum1)

Output:

Enter a list elements separated by space 2 4 6 8 10 12

user list is  ['2', '4', '6', '8', '10', '12']
Sum =  42

Program 2: Get a list of numbers as input from a user and Print it without using a split() function

• First, create an empty list
• Accept list size from the user (i.e. the total number of elements in a list)
• Run loop till the size of a list using for loop and range() function
• use the input() function to receive a number from a user
• add the current number to the list using the append() function

Let see the example now

numberList = []
n = int(input("Enter the list size : "))

print("\n")
for i in range(0, n):
    print("Enter number at location", i, ":")
    item = int(input())
    numberList.append(item)
print("User List is ", numberList)

Output:

Enter the list size : 5

Enter number at location 0 :
10
Enter number at location 1 :
20
Enter number at location 2 :
30
Enter number at location 3 :
40
Enter number at location 4 :
50
User List is  [10, 20, 30, 40, 50]

Program 3: Using list Comprehension

Let’ see how to use the list Comprehension to get the list as an input from the user. First, decide the number of elements.

Use the list Comprehension to do the following task:

• Get numbers from the user using input() function.
• Split it using whitespace and convert each number to an integer using an int() function.
• Add all that numbers to list.

n = int(input("Enter the size of the list "))
print("\n")
numList = list(int(num) for num in input("Enter the list numbers separated by space ").strip().split())[:n]
print("User List: ", numList)

Output:

Enter the size of the list 5

Enter the list numbers separated by space 10 20 30 40 50
User List:  [10, 20, 30, 40, 50]

Program 4: Using the map function

Let’ see how to use the map() function to get a list as an input from the user. First, decide the list size. Next, we accept numbers from the user separated by space, and then we can use the map() function to call int() function for each user entered number.

n = int(input("Enter the size of list : "))
print("\n")
numList = list(map(int, input("Enter the list numbers separated by space ").strip().split()))[:n]
print("User List: ", numList)

Output:

Enter the size of list : 5

Enter the list numbers separated by space 5 10 15 20 25
User List:  [5, 10, 15, 20, 25]

What about getting a list of string as an input?

Python get a list of strings as an input from a user

We can also accept a list of string as an input from the user using the same way as we did for a list of integers. Let’s see the demo.

Python Program to get a list of string as input from a user. In this demo, we are accepting all family member names from a user.

input_string = input("Enter family members separated by space ")
family_list = input_string.split(" ")

print("\n")
print("Printing all family member names")
for name in family_list:
    print(name)

Output:

Enter family members separated by space Jhon, Kelly, Scott, Jessa

Printing all family member names
Jhon,
Kelly,
Scott,
Jessa

Let’s Understand the above program.

1. we accepted the input list element from a user in the format of a string separated by a comma.
2. Using input_string.split(",") we split a string by a comma and created a list of string
3. We iterated a list using for loop and printed all f.amily member names from a list of string

Python Accept a list of lists from user input

In this example, we will see how to get the list of evenly sized lists from the user. In simple words, Let’s see how to accept the following list from a user.

[[10, 20, 30],  [40, 50, 60],  [70, 80, 90]]

listLen = int(input("Enter the number of sublist "))

print("\n")
finalList = [[int(input("Enter number: ")) for _ in range(listLen)] for _ in range(listLen)]
print("List is")
print(finalList)

Output:

Enter the number of sublist 3


Enter number: 10
Enter number: 20
Enter number: 30
Enter number: 40
Enter number: 50
Enter number: 60
Enter number: 70
Enter number: 80
Enter number: 90
List is
[[10, 20, 30], [40, 50, 60], [70, 80, 90]]

Next Steps

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