I'm leaning Kotlin, and I'm wondering if there is a better, simpler and not that complicated way to do this in Kotlin? I need to Write a Kotlin program that loops through an array and generates a histogram based on the numbers in it.The results should look like this(vertically):

1: *****
2: **
3: **
4:
5: *

And this is what I did:

fun main() {
    val myArray: IntArray = intArrayOf(1,2,1,3,3,1,2,1,5,1)
     
     for(num in 1..5){   
        println("")
        print("$num: ")
        for(element in myArray) {
            if(element == num){
                print("*")
            }
     }    
   }
}

CodePudding user response：

You can use the eachCount function to find the count of items in a list.

This is what I came up with:

fun main() {
    
    val map = listOf(1,2,1,3,3,1,2,1,5,1)
        .groupingBy{ it }
        .eachCount()
        
    (1..map.keys.max()).forEach { 
        
        print("\n${it}:")
        
        map[it]?.let { count -> repeat(count){ print("*") } }       
        
    }
    
}

You can see the code here: https://pl.kotl.in/91d7pWDGe

Kotlin Koans is a good place you can learn by writing code. Here is the Koans for Collections: https://play.kotlinlang.org/koans/Collections/Introduction/Task.kt

CodePudding user response：

Not sure if it will be simpler, but you can do something like this:

fun main() {
    val myArray: IntArray = intArrayOf(1, 2, 1, 3, 3, 1, 2, 1, 5, 1)

    for (num in 1..5) {
        println("")
        
        val count = myArray.count { it == num }
        val entries = if (count > 0) "*".repeat(count) else ""
        print("$num: $entries")
    }
}