Recently, DS47 underwent training in Regex (Regular Expression). Although the language initially seemed confusing, it quickly became clear how powerful Regex can be for searching, matching, and manipulating strings of text based on specific patterns and rules.
This blog will cover some of the most used Regex expressions to help beginners familiarise themselves with the language.
Qualifier Expressions
Qualifier expressions are used to pick out particular patterns of text. Some common types are described below:
\w : This pattern codes for any alpha numeric value (any letter or any number). Every character is picked up, apart from spaces:
[a-z] : This pattern codes for any lowercase letter.
[A-Z] : This pattern codes for any uppercase letter.
\d : This pattern codes for any numeric digit.
Quantifier Expressions
Quantifier expressions help a user to express how many characters to pick out from the text.
* : This pattern states zero or more characters will be collected
+ : This pattern states one or more characters will be collected
Combining Quantifier and Qualifier Expressions
Quantifier and qualifier expressions can be used in parallel to help extract whole words, instead of just letters. Some examples include:
\w* : Collects all valid letters until the expression breaks. Because \w does not collect spaces, the expression restarts at every space, hence each word in a string is now collected.
\d+ : Collects all valid digits until the expression breaks.
