regex for matching literal string combinations

Question

I'm a noob with regex.

I have to match literally different combinations of strings. Like in the example:

"feed the cat."
"feed the dog."
"feed the bear."

but NOT

"feed the eagle."
"feed the monkey."
"feed the donkey."

I tried something like /^feed the [cat|dog|bear].$/ but it doesn't work. The cheatsheet available on the net explain a lot of complicated things, but not how I can match several strings literally...

Thank you for the help.

Answer 1

You're slightly confusing some syntax. Here's the correct pattern:

^feed the (cat|dog|bear)\.$

You can also use:

^feed the (?:cat|dog|bear)\.$

if you don't need to capture the animal name.

The square brackets are used for character classes, like [a-z] which means "any lowercase letter between a and z, in ASCII".

Also, note that I escaped . with \., because . means "any character except newline" in regex.

Answer 2

You can try following regex,

feed the (cat|dog|bear)

Working Demo