Compare elements of locals and return distingushing elements

[Nina Bauer]

Dear all,

I have the following three locals:

local house "1 2 3 4"
local garden "1 2 3"
local cat " 4 2 3 1"

Using the following code:

local same : list house === cat
display "`same'"
local distinct : list house === garden
display "`distinct'"

Stata tells me (by displaying 1 and 0, respectively), that cat and house contain the same elements whereas house and garden do not. However, I am not only interested in whether two locals contain the same elements but in case they do not, I would also like to know 1.) which elements are different and 2.) in which local those unique elements are contained. Ideally, I would like to have a new local containing those elements that are contained in one local but not in the other (e.g. 4 is contained in house but not in garden, thus, I would like to have another local difference that contains the 4 as only element. Additionally, it would be great if Stata could tell me that the 4 is contained in house but not in garden.)

Any ideas/solutions how to implement that?

Thank you very much in advance.

Best,
Nina

[daniel klein]

local difference1 : list house - garden
local difference2 : list garden - house
display "`difference1'"
display "`difference2'"

yields

. local difference1 : list house - garden

. local difference2 : list garden - house

. display "`difference1'"
4

. display "`difference2'"


. 
end of do-file

Best
Daniel