fun main() {
    val input = "ABC"
    val output = "ABC,"
    println(input.contains(output,false))
    print(input in (output))
}

Output :

false 
true

I just checked that, in and contains are using same method, but why giving difference results.

CodePudding user response：

The Kotlin contains function

Returns true if this char sequence contains the specified other sequence of characters as a substring.

Actually, you're checking if input.contains(output), and "ABC" does not contain "ABC,".

The correct syntax is

println(output.contains(input,false))