AWK was the first "scripting" language to implement associative arrays, which they claim they took from SNOBOL4. Since then, perl and php have also implemented

AWK was the first "scripting" language to implement associative arrays, which they claim they took from SNOBOL4. Since then, perl and php have also implemented associative arrays. All three can loop over the text index of such an array and produce the original value, which a (bijective) hash cannot do.