Python - Test if all elements in list are of same type

Sometimes, while working with Python, we can have a problem in which we need to test if all the elements of argument are of same type or not. This can have application in many domains such as data Science and day-day programming. Lets discuss certain ways in which this task can be performed.

Method #1 : Using loop + isinstance()
The combination of above functionalities can be used to perform this task. In this, we test for type using isinstance() and check for all elements if they match same type as of 1st element.

# Python3 code to demonstrate  
# Test if all elements in list are of same type 
# using loop + isinstance() 
  
# Initializing lists 
test_list = [5, 6, 2, 5, 7, 9] 
  
# printing original list 
print("The original list is : " + str(test_list)) 
  
# Test if all elements in list are of same type 
# using loop + isinstance() 
res = True
for ele in test_list: 
    if not isinstance(ele, type(test_list[0])): 
        res = False 
        break
  
# printing result  
print ("Do all elements have same type : " + str(res)) 

Output :

The original list is : [5, 6, 2, 5, 7, 9]
Do all elements have same type : True

Method #2 : Using all() + isinstance()
This is yet another way to perform this task. In this, we instead of iterating perform the task in one line using all and instance().

# Python3 code to demonstrate  
# Test if all elements in list are of same type 
# using all() + isinstance() 
  
# Initializing lists 
test_list = [5, 6, 2, 5, 7, 9] 
  
# printing original list 
print("The original list is : " + str(test_list)) 
  
# Test if all elements in list are of same type 
# using all() + isinstance() 
res = all(isinstance(sub, type(test_list[0])) for sub in test_list[1:]) 
  
# printing result  
print ("Do all elements have same type : " + str(res)) 

Output :

The original list is : [5, 6, 2, 5, 7, 9]
Do all elements have same type : True

My Personal Notes

Python – Test if all elements in list are of same type

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