How To Check If A List Contains A Number In Python

In this tutorial, we will learn how to check if a list contains a number in Python. Python, a feature-rich and widely used programming language, offers various built-in methods to accomplish this task.

We will explore some of these methods to efficiently check if a specific number exists in the list, and in the end, we will try out the code provided to solidify your understanding.

Step 1: Using the in keyword

The in keyword is one of the easiest and most straightforward methods to check if a list contains a certain element. It returns True if the specified element is present in the list, and False otherwise.

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my_list = [1, 2, 3, 4, 5]
 
number_to_check = 3
 
if number_to_check in my_list:
    print("The number is present.")
else:
    print("The number is not present.")

Output:
The number is present.

Step 2: Using the list.count() method

The list.count() method returns the number of occurrences of a specific element in a list. If the count is greater than zero, the element is present in the list; otherwise, it is not.

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my_list = [1, 2, 3, 4, 5]
 
number_to_check = 3
 
if my_list.count(number_to_check) > 0:
    print("The number is present.")
else:
    print("The number is not present.")

Output:
The number is present.

Step 3: Using the any() function with a list comprehension

The any() function checks if any element of an iterable (like a list) is True. By combining it with a list comprehension, we can check if any element in the list matches the specified number.

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my_list = [1, 2, 3, 4, 5]
 
number_to_check = 3
 
if any(x == number_to_check for x in my_list):
    print("The number is present.")
else:
    print("The number is not present.")

Output:
The number is present.

Full code example

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my_list = [1, 2, 3, 4, 5]
 
# Using 'in' keyword
number_to_check = 3
 
if number_to_check in my_list:
    print("The number is present.")
else:
    print("The number is not present.")
 
# Using 'list.count()' method
if my_list.count(number_to_check) > 0:
    print("The number is present.")
else:
    print("The number is not present.")
 
# Using 'any()' function with a list comprehension
if any(x == number_to_check for x in my_list):
    print("The number is present.")
else:
    print("The number is not present.")

Output

The number is present.
The number is present.
The number is present.

Conclusion

By following the steps mentioned above, we can easily check if a list contains a number in Python using various methods like the in keyword, the list.count() method, and the any() function with a list comprehension. Each method has its own advantages and use cases, so you can choose the one that best fits your needs.