如果使用正则表达式-字符串匹配整个字符串还是整个字符串+另一个字符？

Question

Sorry if a question like this already has an answer, I wasn't really sure how to word this, so I'll try my best.

How can I make an if statement match an entire string, OR an entire string with an extra character?

---

Let's say the $animals variable has ,dog,cat,pig,bird,goat, stored in it. I want to see if the user-defined variable $your_pet is either one of the comma-separated values OR if it is with an "s" at the end.

So maybe something that would work like:

your_pet=bird

if [[ "${your_pet}" == ,*"${animals}"*, || "${your_pet}"s == ,*"${animals}"*, ]]
then
....

However , I need to check if $your_pet ends in an "s" or not, and accept it if it does or doesn't. (The above code is untested but I am almost certain it would not work).

Here are all of the allowed values of $your_pet :

dog
dogs
cat
cats
pig
pigs
bird
birds
goat
goats

And here are some examples of what would not be allowed:

my dog
my dogs
 dog
hamster
hamsters

I feel like using regex in the if statement would do the trick but I don't know that much about regex to know what to use. (if regex is even needed in a situation like this)

Using bash 3.2.57(1)-release on OS X 10.11.6 El Capitan

Thanks

Answer 1

You can remove the s (if present) and then compare if it matches

your_pet=bird

if [[ "$animals" =~ ",${your_pet%s}," ]]
then
   ...

however, take into account other plurals like goose, geese .