Python – Check List Contains All Elements Of Another List

In this tutorial, we will look at how to check if a list contains all the elements of another list in Python with the help of some examples.

How to check if a list contains all elements of another list?

In Python, you can use a combination of the built-in all() function, list comprehension, and the membership operator to check if a list contains all elements of another list.

Use the following steps to check if all elements in the list ls1 are present in the list ls2 –

• In a list comprehension, for each element in the list ls1, check if it present in the list ls2 using the membership operator, in.
• Apply the Python built-in all() function to return True only if all the items in the above list comprehension correspond to True.

You can use the following syntax to implement the above steps (check if all elements in ls1 are present in ls2).

all([item in ls2 for item in ls1])

It returns True only if all the in ls1 are present in ls2.

Let’s now look at some examples –

# create two lists
ls1 = [1, 2, 3]
ls2 = [1, 2, 3, 4, 5]
# check if ls2 contains all elements from ls1
print(all([item in ls2 for item in ls1]))

Output:

True

We get True as the output since all the elements in the list ls1 are present in the list ls2.

Let’s now look at another example.

# create two lists
ls1 = [1, 2, 6]
ls2 = [1, 2, 3, 4, 5]
# check if ls2 contains all elements from ls1
print(all([item in ls2 for item in ls1]))

Output:

False

Here we get False as the output because not all elements in the list ls1 are present in the list ls2. The element 6 is not present in ls2.

Using set issubset() function

Alternatively, you can convert the two lists to sets and use the set issubset() function to check if all elements in one list are present in another list or not.

# create two lists
ls1 = [1, 2, 3]
ls2 = [1, 2, 3, 4, 5]
# check if ls2 contains all elements from ls1
s1 = set(ls1)
s2 = set(ls2)
print(s1.issubset(s2))

Output:

True

We get the same result as above. Here, we convert the lists ls1 and ls2 to sets s1 and s2 respectively. And then check if the set s1 is a subset of the set s2. This gives us whether all elements in ls1 are present in ls2 or not.

You might also be interested in –

• Python – Check if an element is in a list
• Python – Flatten a list of lists to a single list