May 2008
Intermediate to advanced
172 pages
4h 54m
English
Content preview from JavaScript: The Good Parts
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Elements
Let's look more closely at the elements that make up regular expressions.
Regexp Choice
A regexp choice contains one or more regexp
sequences. The sequences are separated by the | (vertical bar) character. The choice matches if
any of the sequences match. It attempts to match each of the sequences in order.
So:
"into".match(/in|int/)
matches the in in into. It wouldn't match int
because the match of in was
successful.
Regexp Sequence
A regexp sequence contains one or more regexp factors. Each factor can optionally be followed by a quantifier that determines how many times the factor is allowed to appear. If there is no quantifier, then the factor will be matched one time.
Regexp Factor
A regexp factor can be a character, a parenthesized group, a character class, or an escape sequence. All characters are treated literally except for the control characters and the special characters:
\ / [ ] ( ) { } ? + * | . ^ $which must be escaped with a \ prefix if
they are to be matched literally. When in doubt, any special character can be
given a \ prefix to make it literal. The
\ prefix does not
make letters or digits literal.
An unescaped . matches any character except
a line-ending character.
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.