Re: st: foreach loop

[Nick Cox <njcoxstata@gmail.com>]

Look again at the allowed syntaxes for -foreach- in the help.

You can go

foreach x in 1/4 {

but then the next line will be interpreted as

codebook ... if m_marks == 1/4

which is illegal.

You could go (e.g.)

local X 1 2 3 4
foreach x of local X {

or

foreach x of num 1/4 {

but you won't get any unpacking of a list of values with

foreach ... in ... {

as it takes the elements of your list as you type them and 1/4 is a  
single element that is illegal as applied.

See also my tutorial in SJ 2(2): 202-222 (2002).

Nick


On 5 Aug 2012, at 03:03, Lisa Wang <lhwang0925@gmail.com> wrote:

> Hi all,
>
> Can someone please teach me as to why this is invalid:
>
> local x 1 2 3 4
> foreach x in 1/4 {
> codebook a* if m_marks==`x'
> tab a* if m_marks==`x'
> }
>
> I have been learning Stata for only a month, so any suggestions would
> be greatly appreciated. Or how to do it more elegantly would be great
> as well.
>
> I have 4 categories for m_marks only and I wanted to use a local to
> loop over the codebook and tab functions for each category, instead of
> typing it out 4 times.




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