Updated on SSC: listsome - List values of variables for some observations

[Robert Picard]

Thanks to Kit Baum, an updated version of listsome is now available from SSC. To update, use

adoupdate listsome

To install, use

ssc install listsome

Stata's list command does not provide a way to limit the number of observations listed when the if qualifier is used. There are ways to work around the problem but the maximum() option of listsome offers a quick and convenient solution.

listsome is even more useful if you need to list a random sample of the observations in memory. For example,

sysuse auto, clear
set seed 1651651
listsome make-headroom if price < 10000 & mpg > 25, max(5) random

is the equivalent of

preserve
set seed 1651651
gen sortorder = _n
keep if price < 10000 & mpg > 25
sample 5, count
sort sortorder
list make-headroom
restore

When working with datasets with lots of observations, it is impossible to visualize all cases. listsome makes it easy to add to the record (log file) a random sample that illustrates each data cleaning steps of a Stata project. A desirable data cleaning workflow should include

• listing a number of observations that illustrates the problem at hand;
• making a copy of the original variable to preserve the original;
• implementing the solution, usually using a replace statement;
• listing a number of observations that show the results of the change.

listsome is much faster at drawing random samples than Stata's sample command because it does not alter or sort the data in memory. This new version includes faster code to draw random samples and a stand-alone version called randomtag is also available from SSC (type ssc install randomtag in Stata's command window to install).