Python – Lambda Function to Check if value is in a List

Given a list, the task is to write a Python program to check if the value exists in the list or not using the lambda function.

Example:

Input  :  L = [1, 2, 3, 4, 5]
          element = 4
Output :  Element is Present in the list

Input  :  L = [1, 2, 3, 4, 5]
          element = 8
Output :  Element is NOT Present in the list

We can achieve the above functionality using the following two methods.

Method 1: Using Lambda and Count() method

Define a list with integers. Define a lambda function such that it takes array and value as arguments and return the count of value in list.

lambda v:l.count(v)

If the count is zero then print the Element is not present else print element is NOT present.

Python3

arr = [1, 2, 3, 4]
v = 3

def x(arr, v): return arr.count(v)


if(x(arr, v)):
    print("Element is Present in the list")
else:
    print("Element is Not Present in the list")

Output:

Element is Present in the list

Explanation:  The arr and v are passed to the lambda function and it evaluates the count of v in the arr and here v = 3 and it is present 1 time in the array and the if condition is satisfied and prints the element Is present in the list.

Method 2: Using Lambda and in keyword

Define a list with integers. Define a lambda function such that it takes array and value as arguments and check if value is present in array using in keyword

lambda v: True if v in l else False

If the lambda return True then print the Element is present else print element is NOT present.

Python3

arr=[1,2,3,4]
v=8
x=lambda arr,v: True if v in arr else False

if(x(arr,v)):
  print("Element is Present in the list")
else:
  print("Element is Not Present in the list")

Output:

Element is Not Present in the list

Explanation:  The arr and v are passed to the lambda function and it checks if the value is present in an array using IN keyword and here v = 8 and it is NOT Present in the array and returns false so prints the element Is NOT present in the list.