Regular expressions (Regex) are an incredibly useful tool in searching/extracting text for matches within a specific search pattern.
Fields of application include form validation, trasnlating data, replacing strings, and many other uses.
This regex will match strings that contain relative file path or extension.
((\/|\\|\/\/|https?:\\\\|https?:\/\/)[a-z0-9 _@\-^!#$%&+={}.\/\\\[\]]+)+\.[a-z]+$
- Anchors
- Quantifiers
- OR Operator
- Character Classes
- Grouping and Capturing
- Bracket Expressions
- Greedy and Lazy Match
The Anchor used in this regex expression $ indicates the end of a string.
The quantifiers used in this regex expression are ? and +.
? is used in the sequence https?:, indicating the string includes 0 or 1 's'.
+ is used at the end of the sequences ((\/|\\|\/\/|https?:\\\\|https?:\/\/)[a-z0-9 _@\-^!#$%&+={}.\/\\\[\]]+)+ and a-z0-9 _@\-^!#$%&+={}.\/\\\[\]]+ indicating the string includes 1 or more of the previous expression
The OR Operator used in this expression is |
The OR operator indicates the string must include one of the following expressions:
\/, \\, /\/\, https?:\\\\, OR https?:\/\/
In order to be taken literally, the following characters were escaped using a \:
/ as \/
\ as \\
[ as \[
] as /]
Parentheses create a captured group, the group can later be referenced.
Group 0 is the entire expression.
Group 1: ((\/|\\|\/\/|https?:\\\\|https?:\/\/)[a-z0-9 _@\-^!#$%&+={}.\/\\\[\]]+) - This group captures everything up until the file extension part of the string
Group 2: (\/|\\|\/\/|https?:\\\\|https?:\/\/) - This group captures the path of the file extension.
Bracket expressions were used in the regex expression.
[a-z0-9 _@\-^!#$%&+={}.\/\\\[\]] includes any letter or special character in the string before the .
[a-z] - includes any letter in the string after the .
The quantifier + was utilized and is a greedy operator. The + operator will match as far as it possibly can within the text.
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