Comparing Strings in Scala - equals vs ==

Question

I am trying to compare two strings in Scala. Below is the function.

def max(x:Int, y:String): String = {
     | if (y=="Happy") "This is comparing strings as well"
     | else "This is not so fair"
     | if (x > 1) "This is greater than 1"
     | else "This is not greater than 1"
     | }

From some answers I assumed that I can use '==' symbol to compare the strings. I have given the following inputs and got the following outputs. what am I missing or Scala is behaving differently?

max (1,"Happy")
res7: String = This is not greater than 1

println(max(2, "sam"))
This is greater than 1

I think the problem is not with the `==` but the fact that you have two if/else.https://stackoverflow.com/a/12560532/3072566 — litelite, Jun 20 '17 at 19:39
Thanks @litelite. I will keep this question for other's reference. — Dineshkumar, Jun 20 '17 at 19:40

score 2 · Answer 1 · answered Jun 20 '17 at 19:52

This is happening because in scala the last reachable statement's value is the functions result. In this case for "max (1,"Happy")" the code is going inside y="happy" but right after that it is going into the else branch of if(x>1) . As that is the last statement inside the function , you are getting it as the result.

to cross check it introduce a print statement in the first if block

 def max(x:Int, y:String): String = {
     | if (y=="Happy") println("This is comparing strings as well")
     |  else "This is not so fair"
     | if (x > 1) "This is greater than 1"
     | else "This is not greater than 1"
     | }

now call with "max(1,"Happy")"

Result: This is comparing strings as well This is not greater than 1

which shows that you are comparing strings in a right way.

Ramesh Maharjan · Answer 2 · 2017-06-23T01:42:57.293

Your max function is returning only one string and that string is always the last if else statement. If you want both the comparison outputs then you should return a tuple2 of strings as

scala>     def max(x:Int, y:String): (String, String) = {
     |       var string1 =  "This is not greater than 1"
     |       var string2 = "This is not so fair"
     |       if (x > 1) string1 = "This is greater than 1"
     |       if (y=="Happy") string2 = "This is comparing strings as well"
     |       (string1, string2)
     |     }
max: (x: Int, y: String)(String, String)

scala> max(1, "Happy")
res0: (String, String) = (This is not greater than 1,This is comparing strings as well)

scala> res0._1
res1: String = This is not greater than 1

scala> res0._2
res2: String = This is comparing strings as well

scala> max(2, "sam")
res3: (String, String) = (This is greater than 1,This is not so fair)

I hope this answer helps

Comparing Strings in Scala - equals vs ==

2 Answers2