Python 3 Object-Oriented Programming - Third Edition

Matching a selection of characters

Let's start with matching an arbitrary character. The period character, when used in a regular expression pattern, can match any single character. Using a period in the string means you don't care what the character is, just that there is a character there. Here are some examples:

'hello world' matches pattern 'hel.o world'
'helpo world' matches pattern 'hel.o world'
'hel o world' matches pattern 'hel.o world'
'helo world' does not match pattern 'hel.o world'  

Notice how the last example does not match because there is no character at the period's position in the pattern.

That's all well and good, but what if we only want a few specific characters to match? We can put a set of characters inside square brackets ...