Regular expression is a sequence of character(s) mainly used to find and replace patterns in a string or file.
So we can say that the task of searching and extracting is so common that Python has a very powerful library called regular expressions that handles many of these tasks quite elegantly.
| SYMBOL | USAGE |
|---|---|
| $ | Matches the end of the line |
| \s | Matches whitespace |
| \S | Matches any non-whitespace character |
| * | Repeats a character zero or more times |
| \S | Matches any non-whitespace character |
| *? | Repeats a character zero or more times (non-greedy) |
| + | Repeats a character one or more times |
| +? | Repeats a character one or more times (non-greedy) |
| [aeiou] | Matches a single character in the listed set |
| [^XYZ] | Matches a single character not in the listed set |
| [a-z0-9] | The set of characters can include a range |
| ( | Indicates where string extraction is to start |
| ) | Indicates where string extraction is to end |