How important is knowing Regexs?

Question

My personal experience is that regexs solve problems that can't be efficiently solved any other way, and are so frequently required in a world where strings are as important as they are that not having a firm grasp of the subject would be sufficient reason for me to consider not hiring you as a senior programmer (a junior is always allowed the leeway of training).

However.

A number of responses on the recurrent "What's the regex for this?" type-questions suggest that a great deal of coders find them somewhere between unintelligible and opaque.

This is not about whether a simple indexOf or substring is a better solution, that's a technical matter, and sometimes the simple way is correct, sometimes a regex is, and sometimes neither (looking at you html parser questions).

This is about how important it is to understand Regexs and whether the anti-Regex opinion (that trite "...now they have two problems" thing) is merited or FUD.

Should a programmer should be expected to understand Regexs? Is this a required skill?

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edit: just in case it isn't clear, I'm not asking whether I need to learn them (I'm a defender of the faith) but whether the anti-camp have are an evolutionary dead end or whether it's an unnecessary niche skill like InstallShield.

Answer 1

REs let you solve relatively complex problems that would otherwise require you to code up full parsers with backtracking and all that messy sort of stuff. I liken the use of REs to using chainsaws to chop down a tree instead of trying to do it with a piece of celery.

Once you've learned how to use the chainsaw safely, you'll never go back. People who continue to spout anti-RE propaganda will never be as productive as those of us who have learned to love them.

So yes, you should know how to use REs, even if you understand only the basic constructs. They're a tool just like any other.