# RE: st: subscripts for loop?

 From "Nick Cox" <[email protected]> To <[email protected]> Subject RE: st: subscripts for loop? Date Thu, 1 Apr 2004 10:26:29 +0100

```Clearly, it is the leading zeros which
are the challenge here.

Another way of doing it is from considering the effects of

forval i = 1/18 {
local j : di %02.0f `i'
di "`j'"
}

So some loop like

forval i = 1/18 {
local j : di %02.0f `i'
su b0_`j'
}

should be appropriate, where you put whatever
you want to do to the variable.

Strictly, all macros contain strings, so you can
concatenate them by putting them side by side -- except
that in context Stata will often go for the numeric
interpretation of a string.

One exposition linking a introduction to local macros
to one on -for*- is

How to face lists with fortitude. Stata Journal
2(2): 202-222 (2002)

A version of that is accessible at (e.g.)
http://fmwww.bc.edu/RePEc/usug2002/fortitude.pdf

A sequel to that is

Problems with lists. Stata Journal 3(2):
185-202 (2003)

Nick
[email protected]

P.S. strictly Jesper's loop will display the first value of
each variable.

Jesper Sorensen (and Tom Steichen similarly)

> It's not clear what you want to do with the variables, but this loop
> will _display_ them, just make arbitrary changes within the inner
> loops.
>
> forvalues i=1(1)18 {
> 	if `i'<10  {
> 		di b0_0`i'
> 	}
> 	else {
> 		di b0_`i'
> 	}
> }
>

Kenley Barrett

> >I'm stumped on a programming problem. I need to refer to a sequence
> >of variables b0_01, b0_02, b0_03 . . .  b0_18, where the subscript
> >identifies an individual child of a given
> >woman and the first part of the variable refers to some
> characteristic of
> >that child. (The woman is the unit of observation, and for each woman
> >there are up to 18 children observed.) My idea was to do a
> loop with j=1,
> >then j = j+1, etc., referring to b0_j. But this won't work.
> My boyfriend
> >suggested doing the j loop and then concatenating to b0_, but I can't
> >find anything in stata on how to concatenate a number to a string.

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```