Speaking Stata: Loops in parallel

Abstract

This column is a tutorial discussing looping in parallel using foreach and forvalues. Such looping may use not only local macros defined for the purpose but also other devices, including the gettoken command and ways to increment and decrement other macros and to evaluate other expressions.The main idea is that a set of loops in parallel is essentially one loop with two or more sets of parallel actions. Examples cover looping over integers with a required specific display format, generating new variables and defining variable labels at the same time, binning variables as desired, and putting skewness results in new variables. The last example includes some historical comments on the tangled literature on skewness measures using medians and quantiles.