Early Steps

String Has Other Methods Besides =~/match() and sub()

Ask anyone who knows me and they will tell you I'm a huge fan of regular expressions. I use them all the time and my FasterCSV library is a regular expression powered parser. However, even I know they are not for everything, and lately I keep running into almost comical examples of misuse. Here are some of my favorites.

First, we have:

str =~ /=/

That snippet is like calling for a military escort (the regular expression engine) to see you safely to the grocery store down the block. That's fun, but probably overkill. In this case, a call to include?() will do the trick:

str.include?("=")

That may be more like riding your bike to the grocery store, but it gets the job done and is a bit faster to boot.

Funny example number two. I've seen this before:

str =~ /\Aquit\Z/

Again, the regular expression engine appreciates the love, but you really just want ==:

str == "quit"

Even for some of the fancier stuff, you don't need a full blown regular expression. For example, this:

str.sub(/\D+/, "")

could be:

str.delete("^0-9")  # no, that's not a regex

You get the idea. I'm not trying to ban regular expressions. Instead, I just think people should remember there are a lot of other methods in String. When you have a few moments, look up these guys in the documentation:

• String#[]= (can take a regex, but has other fun options)
• String#count
• String#index (can take a regex)
• String#squeeze
• String#rindex (can take a regex)