Kotlin Tutorials

Kotlin Map entries
Syntax & Examples

Syntax of Map.entries

The syntax of Map.entries property is:

abstract val entries: Set<Entry<K, V>>

This entries property of Map returns a read-only Set of all key/value pairs in this map.


✐ Examples

1 Get entries of a map with integer keys and character values

In this example,

  • We create a map named map with integer keys and character values.
  • We access the entries property of the map to get a read-only Set of key/value pairs.
  • We then print the entries to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map = mapOf(1 to 'a', 2 to 'b', 3 to 'c')
    val entries = map.entries
    println(entries)
}

Output

[1=a, 2=b, 3=c]

2 Get entries of a map with string keys and integer values

In this example,

  • We create a map named map with string keys and integer values.
  • We access the entries property of the map to get a read-only Set of key/value pairs.
  • We then print the entries to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map = mapOf("apple" to 1, "banana" to 2, "cherry" to 3)
    val entries = map.entries
    println(entries)
}

Output

[apple=1, banana=2, cherry=3]

3 Iterate over entries of a map and print key-value pairs

In this example,

  • We create a map named map with integer keys and character values.
  • We use a for loop to iterate over each entry in map.entries.
  • For each entry, we extract the key and value and print them to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map = mapOf(1 to 'a', 2 to 'b', 3 to 'c')
    for ((key, value) in map.entries) {
        println("Key: $key, Value: $value")
    }
}

Output

Key: 1, Value: a
Key: 2, Value: b
Key: 3, Value: c

Summary

In this Kotlin tutorial, we learned about entries property of Map: the syntax and few working examples with output and detailed explanation for each example.