Clojure - substring? function

Question

Trying to write a substring function in Clojure. I am sure there is a more idiomatic way. Can anyone enlighten me?

Otherwise, here is my version. Thoughts?

(defn substring? 
 "is 'sub' in 'str'?"
 [sub str] 
 (if (not= (.indexOf str sub) -1) 
 true 
 false))

• decentral1se: hmmm...just discovered - (.contains "abcdefghi" "abc"), anyway that doesn't interop with Java (purely out of curiosity!)?
• georgek: a re-find might be the simplest way. The old contrib.string used .contains as well so it was probably the best tool for the job.

Answer 1

As you wrote in your comments, (.contains "str" "sub") is perfectly fine. it is indeed java interop - it runs the method contains on String object "str".

two more comments, first, passing str as a var name isnt so good, since str is a function, so you should consider giving it a different name. Second, in your implementation, its quite redundant to write

(defn substring? [sub st]
 (if (not= (.indexOf st sub) -1) 
 true 
 false))

You could simply write

(defn substring? [sub st]
 (not= (.indexOf st sub) -1))