How can I generate alternatives from a list of strings?

Questions
1

Hi everyone,

How can I create alternatives from a list of strings to be used as a string pattern in StringPosition.
For example, if my function is fed

{"cat","dog","bird}

I want

"cat" | "dog" | "bird"

But if my list has only two strings in it

{"cat","dog"}

I want

"cat" | "dog"

In other words, I want to be able to generate alternatives from a list of unknown length.

I guess a related question is, What is the difference between using

StringPosition[myText,"cat"|"dog"~~WordBoundary]

and

StringPosition[myText,{"cat","dog"}~~WordBoundary]

because both seems to work the same in my tests?

Regards,

Gregory

2

Alternatives@@{“cat”,“dog”,"bird}

3

Hi Christopher,

Thanks! Had no idea there was a function called Alternatives because I had only ever seen it as

|

I’m feeling pretty embarrassed.

Gregory

4

Don’t feel bad. There are plenty of infix symbol shortcuts in common use in Wolfram Language. Many of whom the full function names are not well known or used much at all.

sym:patt is Pattern
patt1_?patt2 is PatternTest
expr1;expr2 is CompoundExpression
5

Thanks once again, Christopher. The language tutorial will be helpful because sometimes I need to use full function names when teaching students Mathematica.

Gregory

6

Just a remark: One can even be more general (using some operator op)

Infix@*op @@ {"cat", "dog", "bird"}
(*  Out:  "cat" ~op~ "dog" ~op~ "bird"  *)

Henrik

7

Much obliged, Henrik. I will add this to my growing bag of tips!

Gregory