A computer-implemented method for a computing environment employing a matrix-based mathematical programming language includes: generating a heterogeneous dataset in the computing environment, where the heterogeneous dataset embodies a plurality of variables for a plurality of subjects, where each element of a respective variable has a same data type, where the variables comprise at least two data types; accessing contents of the heterogeneous dataset with a single command in the computing environment, where the single command is a brace command, a dot command, or a parentheses command; and providing in the computing environment a portion of the heterogeneous dataset based on the single command.