The typical way of using forEach() (things.forEach { println(it) }) makes it look like forEach() is not a function. It is, but functions whose last parameter is a lambda expression can have the expression appear outside the parentheses. And, if there are no other parameters to the function, you can skip the parentheses entirely. So, this snippet is the same as the previous one, just with a more function-like syntax.

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Accessing Elements via [] Array Modification Arrays filter() for Loop forEach() forEach() is a Function map() map() Type Conversions Typed Arrays
Accessing Elements via [] any() any() and Short Circuits Array Modification Arrays Combining Collections filter() first() first() Sans Lambda firstOrNull() firstOrNull() and the Elvis Operator fold() for Loop forEach() forEach() is a Function joinToString() Lists map() map() Type Conversions Maps Mutable Lists Sets Typed Arrays
Accessing Elements via [] Combining Collections filter() for Loop forEach() forEach() is a Function Lists map() map() Type Conversions Mutable Lists
Accessing Elements via [] Combining Collections for Loop forEach() forEach() is a Function Maps
filter() for Loop forEach() forEach() is a Function map() map() Type Conversions Sets
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