filter
inline fun <K, V> Map<out K, V>.filterKeys(predicate: (K) -> Boolean): Map<K, V>
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Returns a map containing all key-value pairs with keys matching the given predicate.
The returned map preserves the entry iteration order of the original map.
Samples
import samples.*
import kotlin.test.*
import java.util.*
fun main() {
//sampleStart
val originalMap = mapOf("key1" to 1, "key2" to 2, "something_else" to 3)
val filteredMap = originalMap.filterKeys { it.contains("key") }
assertPrints(filteredMap, "{key1=1, key2=2}")
// original map has not changed
assertPrints(originalMap, "{key1=1, key2=2, something_else=3}")
val nonMatchingPredicate: (String) -> Boolean = { it == "key3" }
val emptyMap = originalMap.filterKeys(nonMatchingPredicate)
assertPrints(emptyMap, "{}")
//sampleEnd
}