regexes

Commonly referred to as regexes, regular expressions are a feature of nearly all modern programming languages.

To help you catch runaway backtracking early, always test your regexes with long strings that contain partial matches.

Since JRuby aims to be a compatible implementation of Ruby 1. 8. x (or future versions), it's necessary to support the same Regexes.

Regexes are not always the best tool for the job, especially when you are merely searching for literal strings.

However, this proved too complex with long regexes (it was difficult to decide how the group elements related to the regex).

Using a concise shorthand, regexes describe the form of data and decompose it.

As introduced in Part 1, regexes are one of the most powerful tools for manipulating data.

Regexes in Scala should contain no surprises if you've used them in other programming languages.

Since the fields have a fixed length, the regexes are simple, taking the form . {5}, which means "any character, repeated five times. "

The important thing is to avoid repeatedly recompiling regexes within loops.

You can concatenate and combine the primitives in Table 1 (and other operators) and use them in combination to build (very) complex regexes.

Now I delve more deeply into regexes and look at a handful of advanced operators and recipes.

When used with care, regexes are very fast.

Regexes can remember what's been matched with capture.

Just because two regexes match the same text doesn't mean they do so at the same speed.

Think about the kinds of strings that your regexes will nearly but not quite match, and include those in your tests.

Make your regexes portable with character classes