How to only keep obvs whose "industry_vertical" value matches a long list of industry verticals

[Olivia Johns]

I have a list of firms, firms values, and a variable "industry_verticals" which contains thousands of different values for industry verticals. In my dataset (total of 50000 firms), i have a smaller set of sample (let's say 500 firms) whose industry verticals include around 400 different industry vertical values. I want to use this 400 values to pick out all the firms in the whole dataset (50000 firms) whose "industry_vertical" value matches one of the 400 values from the sub-sample. I am not sure if this is possible with STATA. I will appreciate any help.

[Øyvind Snilsberg]

use small_dataset.dta, clear
keep industry_verticals
by industry_verticals, sort: keep if _n==1 //possibly redundant
merge 1:m industry_verticals using whole_dataset.dta, keep(3) nogen

[Nick Cox]

See https://www.stata.com/support/faqs/d...s-for-subsets/ for more on the method in #2.