[R] debug in a loop

[Duncan Murdoch]

On 12-02-10 12:48 PM, Justin Haynes wrote:
> You can add
>
> if(is.na(tab[i])) browser()
>
> or
>
> if(is.na(tab[i])) break
>
> see inline

You can also do this temporarily.  Supposing that you used 
source("foo.R") to enter a function with that code in it, and you want 
the check on line 10, you'd enter

setBreakpoint("foo.R#10", tracer=quote(if(is.na(tab[i])) browser()))

Duncan Murdoch

>
> On Fri, Feb 10, 2012 at 7:22 AM, ikuzar<razuki at hotmail.fr>  wrote:
>
>> Hi,
>>
>> I'd like to debug in a loop (using debug() and browser() etc but not
>> print()
>> ). I'am looking for the first occurence of NA.
>> For instance:
>>
>> tab = c(1:300)
>> tab[250] = NA
>> len = length(tab)
>> for (i in 1:len){
>>    if(i != len){
>>
>         if(is.na(tab[i])) browser()
>
>>      tab[i] = tab[i]+tab[i+1]
>>    }
>> }
>>
>> I do not want to do "Browse[2]>  n" for each step ... I'd like to declare a
>> "browser()" in the loop with a condition. But how to write "stop running
>> when you encounter NA" ?
>>
>> Thanks for your help
>>
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/debug-in-a-loop-tp4376563p4376563.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
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>>
>
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>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.