What is the difference between encasing part of a regular expression in () (parentheses) and doing it in [] (square brackets)?
How does this:
[a-z0-9]
differ from this:
(a-z0-9)
?
See Question&Answers more detail:osWhat is the difference between encasing part of a regular expression in () (parentheses) and doing it in [] (square brackets)?
How does this:
[a-z0-9]
differ from this:
(a-z0-9)
?
See Question&Answers more detail:os[]
denotes a character class. ()
denotes a capturing group.
[a-z0-9]
-- One character that is in the range of a-z
OR 0-9
(a-z0-9)
-- Explicit capture of a-z0-9
. No ranges.
a
-- Can be captured by [a-z0-9]
.
a-z0-9
-- Can be captured by (a-z0-9)
and then can be referenced in a replacement and/or later in the expression.