Need to find the length of an object in Python? Meet your new friend, the len() function. The official Python documentation’s definition of len() is:
Return the length (the number of items) of an object. The argument may be a sequence (such as a string, bytes, tuple, list, or range) or a collection (such as a dictionary, set, or frozen set).
As noted by the documentation, len() can be used on multiple different object types. The first thing that comes to most people’s minds when talking about length, is the length of a string. For example:
>>> phrase = "Hello there, General Kenobi"
>>> len(phrase)
27
However len() can also be used on other objects, such as lists:
>>> colors = ["Red", "Blue", "Green"]
>>> len(colors)
3
or tuples:
>>> cars = ("Mustang", "Corvette")
>>> len(cars)
2
or range objects:
>>> numbers = range(1, 30, 2)
>>> len(numbers)
15
As seen, the len() function is a powerful tool in Python. However, there are some objects that will cause a TypeError, as their object type “has no len()”. These include integers, booleans, floats, and complex numbers. That’s all there is for the len() function, a simple tool, that has multiple applications that can be used in your Python code.