how do I use IndexOf with an object Array of a data class?

Question

fun main() {
    data class seriesData( 
        var seriesName: String = "",
        var bookListEntries: MutableList<Int> = arrayListOf() {}
    var mySeriesData: MutableList<seriesData> = ArrayList()
    for (i in 0..5) {
        var myString: String = "series" + i.toString() 
        mySeriesData.add(seriesData(seriesName = myString, 
                                    bookListEntries = ArrayList()))
    }
    // I want to find an occurrence of one of the strings
    println(mySeriesData.seriesName.indexOf("series2")) 
    // The last statement always gives me unresolved reference on seriesName
}

I have tried several variations of the above including putting the two variables in the body of the data class with a dummy key and using "it." with no success. I am new to Kotlin. I know some of the above code can be streamlined, but I broke it out to help clarify the steps.

Answer 1

This indexOf function is gives you entire data class not a single value under the data class

For example

If you have below data class

data class seriesData(
    var seriesName: String = "",
    var bookListEntries: MutableList<Int> = arrayListOf(),
)

And you run the loop on this data class for fill the value of variables under the data class

val mySeriesData: MutableList<seriesData> = ArrayList()

for (i in 0 .. 5) {
    var myString: String = "series" + i.toString()
    mySeriesData.add(
        seriesData(
            seriesName = myString,
            bookListEntries = ArrayList()
        )
    )
}

And now you wants to know that which is the index of "series2" value

Then you need a entire data class for that

in the indexOf function you need to pass entire data class like this :

mySeriesData.indexOf(seriesData("series3", ArrayList()))

• save above line into one variable and it gives the index of that data class of that particular value.