Character sets

We learned how to match different words.
For this task you could do cat|bat|rat, but this would be boring

We can use character sets to match one of the characters in the set.
For example, [abc] will match a, b or c

Task

Match cat, bat and rat

/ /

cat bat rat mat

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Regex Cheatsheet

Here you find every Regex character explained

Anchors

^ - Start of a string
$ - End of a string
\b - Word boundary
\B - Not word boundary

Quantifiers

? - Optional
+ - 1 or more times
* - 0 or more times
{n} - Exactly n times
{n,} - at least n times
{,m} - at most m times
{n,m} - Between n and m times

Character Classes

[abc] - Character Set
[^abc] - Not in character set
[a-z] - Range of characters
. - Any character except newline
\d - Digit
\D - Not a digit
\w - Word character
\W - Not a word character
\s - Whitespace
\S - Not whitespace

Groups

(abc) - Capturing group
(?:abc) - Non-capturing group
\1 - Group Reference

Lookarounds

(?=abc) - Positive lookahead
(?!abc) - Negative lookahead
(?<=abc) - Positive lookbehind
(?<!abc) - Negative lookbehind

Flags

g - Global
i - Case-insensitive
m - Multiline

Other Characters

\[Symbol] - Use a Regex Symbol as Text
| - Or