Error : the value of the type parameter t should be mentioned in input types-CodePudding

I am beginner at kotlin and I am trying to find if the input letter is in the range of the letters

fun main(){
    var letters = 'a'..'f' step(2)
    var yourLetter = readLine()!!.toCharArray()
    if(yourLetter in letters){
        print("that's here")
    }else{
        print("that's not here")
    }
}

the code return error in

Kotlin: Type inference failed. The value of the type parameter T should be mentioned in input types (argument types, receiver type or expected type). Try to specify it explicitly.

how can I solve this problem ?

CodePudding user response：

both letters and yourLetter are collections of chars. if your input is "abc" for example then yourLetter will become ['a','b','c']. If you only want to look at the first character that was provided you could do

fun main(){
    var letters = 'a'..'f' step(2)
    var yourLetter = readLine()!![0] //note: you don't need to convert to CharArray
    if(yourLetter in letters){
        print("that's here")
    }else{
        print("that's not here")
    }
}

if you want to check if any of the input characters are in it you could do

fun main(){
    var letters = 'a'..'f' step(2)
    var yourLetter = readLine()!!
    if(yourLetter.any {it in letters}){
        print("that's here")
    }else{
        print("that's not here")
    }
}