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 |