In the sample search, a regular expression can be filled in in order to search, for example, for a specific combination of characters. The Python syntax for regular expressions is used. The search returns a distribution map and examples of the string.
In regular expressions a number of characters have a special meaning. For example:
| . | matches any character |
| ^ | matches the beginning of a string |
| $ | matches the end of a string |
| [] | indicates a set of characters |
| [^] | matches characters NOT within the set |
Examples of regular expressions:
| n | finds all instances which contain the charcater 'n' |
| ng | finds all instances which contain 'ng' |
| ^a | finds all instances of 'a' in the beginning of a string |
| a$ | finds all instances of 'a' in the end of a string |
| ^.a | finds all instances were 'a' is the second symbol |
| a.e | finds an 'a' followed by any single character followed by an 'e' |
| [ae] | all instances of either 'a' or 'e' |
| ^[ae] | all instances beginning with either 'a' or 'e' |
| [^ae] | matches instances NOT containing 'a' or 'e' |
| [^a]$ | matches all instances that do NOT end with an 'a' |
| t[ae] | 't' followed by either 'a' or 'e' |