Associative Arrays

int[ char[] ] keywords;
char[] abc;
...
keywords["foo"] = 3;
...
if (keywords[abc] == 3)
{
	...
}
...
foreach (char[] kwd, int value; keywords)
{
	writefln(kwd, " = ", value);
}

Sparse Array of Ints

int[int] sa;
sa[1] = 3;
sa[1000] = 16;