How to check the equality of strings in clojure without invoking java.lang.String?

Question

Is there any way in clojure to check the equality of strings? i.e. I need to know, whether their contents is equal, not location.

thanks.

Answer 1

Equality in Clojure (the = function) always tests value, not identity, so two strings are = if they have the same contents.

For most Java types, including String, Clojure = dispatches to Java .equals. String.equals is defined as "represents the same sequence of characters."

If you want to test identity (Are these pointers to the same location in memory?) use the identical? function.

Answer 2

(= "hello" (str "hel" "lo"))
; => true 

The JVM has a string pool that holds at most one entry per value, so identity and value equality are the same comparison. There are ways using StringBuilder. and String. where this is not strictly true, but because the clojure equality function calls .equals, a value comparison will be performed if the identities are different.