The use of regular expressions is a widespread approach that is used in search engines and text-processing utilities. Many programming languages support regexes out-of-the-box or use libraries. Good examples of such usage include the Find and Find in path actions in IntelliJ IDEA, which can be used to find code. The Find in path window looks as follows:
To find a sequence of characters using regular expressions, we have to provide a pattern that consists of special characters; these are listed as follows:
| Subexpression | Matches |
|---|---|
| ^ | The search sequence of characters must start from the beginning of the line. |
| $ | The search sequence of characters must be at the end of the line. |
| . | The search character may be any except the new line. The m option allows you to find the new line character as well. |
| [...] | The search character may be any one in brackets... |