RE: st: continuing a loop from after it encounters an error

[Nick Cox <n.j.cox@durham.ac.uk>]

My answer is the same, extended. 

1. Use -capture- if you must do this. 

2. I can't see why you would ever need to do anything like this. Just loop over a varlist. The globals are just middlemen here who can be cut. 

Nick 
n.j.cox@durham.ac.uk 

Nick Mosely

OK, youre right, my example was weak. Here is a more accurate look at
what I am trying to accomplish:

set obs 1
g object1 = 1
g object3 = 3
global p1 object1
global p2 object2
global p3 object3
foreach i of numlist 1/3 {
	foreach j of global p`i' {
		tabulate `j'
	}
}

    object1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          1      100.00      100.00
------------+-----------------------------------
      Total |          1      100.00
variable object2 not found
r(111);

I hope this makes it more clear. Thanks!

On Thu, Feb 3, 2011 at 10:54 AM, Eric Booth <ebooth@ppri.tamu.edu> wrote:
> <>
>
> I'm still not clear on what the "objects" are.  You mention that are "commands" and then you -display- them. Also, when I run your code, I don't get the r(199) error about it being an unrecognized command -- so there's something important missing from your example.
>
> Take a look at -help confirm- and decide which objects you are trying to confirm exist.
> If these are variables you can:
>
> **************************!
> clear
>  set obs 10
>  g object1 = 1
>  g object3 = 3
>
> ****
> foreach i in object1 object2 object3 {
> cap confirm variable `i'
>   if !_rc {
>        display `i'
>        }
> }
> **************************!
>
> If these are commands, you can also use -which- and -capture- to check to see if they are installed:
> **************************!
> clear
> foreach i in  describe object1 object3 list  {
>        cap which `i'
>        if _rc continue
> }
> **************************!
>
> On Feb 3, 2011, at 12:41 PM, Nick Mosely wrote:

>> I've built a loop that encounters an error periodically due to the
>> fact that stata can't find one of the objects specified in the list. I
>> don't mind the error, but I would like stata to skip objects in list
>> that encounter the error and continue to the next iteration of the
>> loop, rather than breaking the loop. I've tried the continue command,
>> but am not sure that is what it's meant for.
>>
>> Here is a simplified version of the code. In this example, assume that
>> objects1 and object3 are valid commands but object2 is not:
>>
>> foreach i in object1 object2 object3 {
>> display `i'
>> continue
>> }
>>> object1
>>> unrecognized command:  object2
>>> r(199);
>>
>> What can I do get the code to continue running through object3?
>>

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