Python's len() method can be used to easily find the length of a string. It's a simple and quick way to measure the length of a string (the number of characters) without having to write a lot of code. The syntax for using the len() method is fairly straightforward, and hard to mess up. Even I can manage it.

from sys import argv

script, file = argv

source = open(file)
indata = source.read()

print "The file called '%s' is %s bytes in length." % (file, len(indata))

Remember that len() calculates the string so it can be used for characters too. You could ask Python to count the letters in a word or sentence.