The OpenD Programming Language

byKey

Returns a forward range which will iterate over the keys of the associative array. The keys are returned by reference.

If structural changes are made to the array (removing or adding keys), all ranges previously obtained through this function are invalidated. The following example program will dereference a null pointer:

import std.stdio : writeln;

auto dict = ["k1": 1, "k2": 2];
auto keyRange = dict.byKey;
dict.clear;
writeln(keyRange.front);    // Segmentation fault
  1. auto byKey(T aa)
  2. auto byKey(T* aa)
    pure nothrow @nogc
    byKey
    (
    T : V[K]
    K
    V
    )
    (
    T* aa
    )

Parameters

aa T*

The associative array.

Return Value

Type: auto

A forward range referencing the keys of the associative array.

Examples

auto dict = [1: "v1", 2: "v2"];
int sum;
foreach (v; dict.byKey)
    sum += v;

assert(sum == 3);

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