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Python | Test if all elements are present in list

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  • Last Updated : 25 Jan, 2023
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Sometimes, while working with Python list, we have a problem in which we need to check for a particular list of values and want to be sure if a target list contains all the given values. This has it’s application in web development domain when required some type of filtering. Let’s discuss a way in which this task can be performed. 
Method : Using list comprehension + all() This task can be performed using the inbuilt functionality of all(). The all() can be fed with list comprehension logic to check if element of test list is present in target list and rest is done by all(). 

Python3




# Python3 code to demonstrate working of
# Test if all elements are present in list
# Using list comprehension + all()
 
# initializing list
target_list = [6, 4, 8, 9, 10]
 
# initializing test list
test_list = [4, 6, 9]
 
# printing lists
print("The target list : " + str(target_list))
print("The test list : " + str(test_list))
 
# Test if all elements are present in list
# Using list comprehension + all()
res = all(ele in target_list for ele in test_list)
 
# Printing result
print("Does every element of test_list is in target_list ? : " + str(res))

Output

The target list : [6, 4, 8, 9, 10]
The test list : [4, 6, 9]
Does every element of test_list is in target_list ? : True

Method #2: Using Counter() function

Python3




# Python3 code to demonstrate working of
# Test if all elements are present in list
# initializing list
from collections import Counter
target_list = [6, 4, 8, 9, 10]
 
# initializing test list
test_list = [4, 6, 9]
 
# printing lists
print("The target list : " + str(target_list))
print("The test list : " + str(test_list))
 
# Test if all elements are present in list
freq = Counter(target_list)
res = True
for i in test_list:
    if i not in freq.keys():
        res = False
 
# Printing result
print("Does every element of test_list is in target_list ? : " + str(res))

Output

The target list : [6, 4, 8, 9, 10]
The test list : [4, 6, 9]
Does every element of test_list is in target_list ? : True

Method 3: Using set().issubset()

In this method, we first convert the test_list into a set, then use the issubset() function which returns true if all elements of the set are present in the target list.

Python3




# Python3 code to demonstrate working of
# Test if all elements are present in list
# Using set().issubset()
 
# initializing list
target_list = [6, 4, 8, 9, 10]
 
# initializing test list
test_list = [4, 6, 9]
 
# printing lists
print("The target list : " + str(target_list))
print("The test list : " + str(test_list))
 
# Test if all elements are present in list
res = set(test_list).issubset(target_list)
 
# Printing result
print("Does every element of test_list is in target_list ? : " + str(res))
#This code is contributed by Edula Vinay Kumar Reddy

Output

The target list : [6, 4, 8, 9, 10]
The test list : [4, 6, 9]
Does every element of test_list is in target_list ? : True

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


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