Python | Check if all elements in a List are same

Given a list, write a Python program to check if all the elements in the given list are the same. 

Example:

Input: ['Geeks', 'Geeks', 'Geeks', 'Geeks', ]
Output: Yes

Input: ['Geeks', 'Is', 'all', 'Same', ]
Output: No

There are various ways we can do this task. Let’s see different ways we can check if all elements in a List are the same. 

Method #1: Comparing each element. 

Python3

# Python program to check if all
# elements in a List are same


def checkList(lst):

    ele = lst[0]
    chk = True

    # Comparing each element with first item
    for item in lst:
        if ele != item:
            chk = False
            break

    if (chk == True):
        print("Equal")
    else:
        print("Not equal")


# Driver Code
lst = ['Geeks', 'Geeks', 'Geeks', 'Geeks', ]
checkList(lst)

Output

Equal

But In Python, we can do the same task in many interesting ways. 

Method #2: Using all() method 

Python3

# Python program to check if all
# elements in a List are same
res = False


def chkList(lst):
    if len(lst) < 0:
        res = True
    res = all(ele == lst[0] for ele in lst)

    if(res):
        print("Equal")
    else:
        print("Not equal")


# Driver Code
lst = ['Geeks', 'Geeks', 'Geeks', 'Geeks']
chkList(lst)

Output

Equal

Method #3: Using count() method 

Python3

# Python program to check if all
# elements in a List are same
res = False


def chkList(lst):
    if len(lst) < 0:
        res = True
    res = lst.count(lst[0]) == len(lst)

    if(res):
        print("Equal")
    else:
        print("Not equal")


# Driver Code
lst = ['Geeks', 'Geeks', 'Geeks', 'Geeks']
chkList(lst)

Output

Equal

Method #4: Using set data structure Since we know there cannot be duplicate elements in a set, we can use this property to check whether all the elements are same or not. 

Python3

# Python program to check if all
# elements in a List are same


def chkList(lst):
    return len(set(lst)) == 1


# Driver Code
lst = ['Geeks', 'Geeks', 'Geeks', 'Geeks']

if chkList(lst) == True:
    print("Equal")
else:
    print("Not Equal")

Output

Equal

Method #5 : Using len() method

Python3

# Python program to check if all
# elements in a List are same
lst = ['Geeks', 'Geeks', 'Geeks', 'Geeks']
if([lst[0]]*len(lst) == lst):
    print("Equal")
else:
    print("Not equal")

Output

Equal

Method#6: Using recursion

Python3

#Python program to check if all the elements in the given list are the same.
def checkList(lst, ele=None, index=0):
    # if ele is None, assign the first element of the list to ele
    if ele is None:
        ele = lst[0]
    # base case: if index is equal to the length of the list, return True
    if index == len(lst):
        return True
    # if the current element at index is not equal to ele, return False
    elif lst[index] != ele:
        return False
    # otherwise, call the function again with the next index
    else:
        return checkList(lst, ele, index+1)

# Driver Code
lst = ['Geeks', 'Geeks', 'Geeks', 'Geeks']
# check if the function returns True
if checkList(lst):
    print("Equal")
else:
    print("Not equal")

#This code is contributed Vinay Pinjala.

Output

Equal

Time Complexity: O(n)
Auxiliary Space: O(n)

Method #7: Using the reduce function from the functools library and the operator module:

Python3

from functools import reduce
import operator

def all_elements_same(lst):
    return reduce(operator.eq, lst)

# driver code
lst = [1,1,1,1,1]
if all_elements_same(lst):
    print("Equal")
else:
    print("Not Equal")

Output:

Equal

Time Complexity: O(n)
Auxiliary Space: O(n)