To use the len() function in Python, you simply pass an object as an argument, and len() will return the number of items in that object. Here are some examples:
Getting the length of a string:
s = "Hello, world!"
length = len(s)
print(length) # output: 13
Getting the length of a list:
my_list = [1, 2, 3, 4, 5]
length = len(my_list)
print(length) # output: 5
Getting the length of a dictionary:
my_dict = {"a": 1, "b": 2, "c": 3}
length = len(my_dict)
print(length) # output: 3
Note that the len() function only works with objects that have a defined length, such as strings, lists, and dictionaries, among others. If you try to use len() with an object that doesn’t have a defined length, you’ll get a TypeError exception.