Some of the most common metacharacters used in Regex along with usage:
.
matches any character including whitespace.
+
matches 1 or more occurrences of the preceding subexpression.
?
matches 0 or 1 occurrence of the preceding subexpression.
*
matches 0 or more occurrences of the preceding subexpression.
\d
matches any digit character.
\w
matches any alphanumeric character [A-Z][a-z][0–9]. Not case sensitive.
{m}
Matches exactly m occurrences of the preceding subexpression.
{m,}
Matches at least m occurrences of the preceding subexpression.
{m,n}
Matches at least m, but not more than n occurrences of the preceding subexpression.
[….]
Matches any character inside the brackets.
[^….]
Matches any character not in the brackets.
(….)
Matches the expression inside the brackets exactly.
|
Matches either preceding or succeeding.
^
Matches the subsequent expression only when it occurs at the beginning of the string.
$
Matches the preceding expression only when it occurs at the end of the string.
