How to refer to the first element in a macro?

[Riham Omar]

Hello all

I am trying to display the content of stored macros in comma separated format , and wanted to put a header before displaying the macros, I am looping across different datasets and different measures. If I used the disp code directly it would be repeated by the number of looped datasets. therefore, I thought of only displaying the header if it was the first element (dataset) in the datasets macro. is there a way to refer to the first element in the macro, without specifying its name i.e if the dataset macro contains "tr12 sk10" , I don't want to refer to tr12 specifically but rather the first element so that the code can be more general? or is there some other way to disp a header in a loop to be displayed only once.

Thanks in advance
R

[Nick Cox]

Here are three ways to do it:

. local foo tr12 sk10

. tokenize "`foo'"

. di "`1'"
tr12

. di word("`foo'", 1)
tr12

. di "`: word 1 of `foo''"
tr12

[Riham Omar]

Thank you Nick for your reply. however, when I apply the following code (part from the loop) i get the following error message,

tokenize " `dataset' "
if ` dataset' ="1" di "dataset,measure1,measure2 "
di "` dataset',`,m1',`m2' "
tr12 not found

I also got the same message when I was trying to use (if i=1/"`ccyy' " di "dataset,measure1,measure2 " )

I think there is something wrong with the code that I cannot figure it out.

Thanks in advance!

[Nick Cox]

You're right. There are errors in your code: I spotted five.

1. Should be if "`dataset'" not if `dataset'

2. (Corrected above) Remove spaces from macro references. "` dataset'" should be "`dataset'"

3. Use == rather than = for testing equality.

4. A literal test for equality with "1" doesn't seem what you want here.

5. Your last statement seems to need an else

There may be others, but I can't check given that you haven't shown us the definitions of all the macros.