How do I check if a value is in a list in Python?
Antek N

In Python, you can check if a value is present in a list using thein operator. Here's a detailed explanation of how to accomplish this:

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my_list = [1, 2, 3, 4, 5]

if 3 in my_list:
    print("Value is in the list.")
else:
    print("Value is not in the list.")

In this example, thein operator is used to check if the value3 is present in the listmy_list. If the value is found, the condition evaluates toTrue, and the corresponding message is printed. If you want to check for the absence of a value in the list, you can use thenot in operator:

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my_list = [1, 2, 3, 4, 5]

if 6 not in my_list:
    print("Value is not in the list.")
else:
    print("Value is in the list.")

In this case,6 not in my_list checks if the value6 is not present in the list. If the value is not found, the condition evaluates toTrue, and the corresponding message is printed. Thein andnot in operators are case-sensitive, meaning that they perform exact matches. If you need to perform case-insensitive searches or use custom comparison logic, you can iterate over the list or use other techniques such as list comprehension.

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my_list = ["apple", "banana", "orange"]

value = "Banana"

if value.lower() in [item.lower() for item in my_list]:
    print("Value is in the list (case-insensitive).")
else:
    print("Value is not in the list (case-insensitive).")

In this example, a case-insensitive search is performed by converting both the value and the elements in the list to lowercase using thelower() method. The list comprehension[item.lower() for item in my_list] creates a new list with lowercase elements. Then, thevalue.lower() in ... expression checks if the lowercase value is present in the lowercase list. By using thein andnot in operators, along with additional techniques if necessary, you can check if a value is present in a list in Python. Choose the approach that best suits your needs based on the specific comparison requirements.

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