minusAssign

inline operator fun <K, V> MutableMap<K, V>.minusAssign(key: K)(source)

fun main() {
    val map = mutableMapOf("a" to 1, "b" to 2, "c" to 3)
    map -= "b"          // removes the entry with key "b"
    println(map)        // prints {a=1, c=3}
}