How to check if a value exists in a list in Python?

Using the in operator.

# List example
my_list = [1, 2, 3, 4, 5]

# Value to check
value_to_check = 3

# Existence check
if value_to_check in my_list:
    print(f"{value_to_check} exists in the list.")
else:
    print(f"{value_to_check} does not exist in the list.")

# Another example
another_value = 10
if another_value in my_list:
    print(f"{another_value} exists in the list.")
else:
    print(f"{another_value} does not exist in the list.")