[R] how to break the loop using sapply?

[Jeff Newmiller]

Is it possible to break it? I already told you that... NO. Also your mention of efficiency is not relevant. Keep in mind that apply functions are not significantly faster than for loops or while loops. They are just compact ways to express your intent. Usually people having speed problems with for loops are doing something wasteful inside their loop.

Re you're alternate question: you can't do that either. Your use of seq is the correct way if that is what you want to do.

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Sent from my phone. Please excuse my brevity.

On October 9, 2014 11:12:33 PM PDT, PO SU <rhelpmaillist at 163.com> wrote:
>
>
>Is that mean while may be more effient than  for in R? as i know, while
>and for  are all just functions in R. 
>Tks for your suggestion to not use apply that way, but i want to know,
>if possible, is there any way to break it ?
>Actually, there is a additional question:
>  x<- c(3,4,5,6,9)
> sapply(x ,function(i){
>foo(i)  #do something to each value in x,how can i know the i's index
>in x?
>)}
>In my way , i always 
>sapply(seq(x),function(i){
>foo(x[i])
>})
>or 
>Map( function(i,index){
>foo(i)  # through index to know the i's index in x
>},x ,seq(x)) 
>
>How you solve the problem? I mean just use apply functions.
>
>
>
>--
>
>PO SU
>mail: desolator88 at 163.com 
>Majored in Statistics from SJTU
>
>
>
>
>At 2014-10-10 13:58:29, "Jeff Newmiller" <jdnewmil at dcn.davis.CA.us>
>wrote:
>>Don't use apply functions if you want to do what you describe. They
>don't work that way. Use a while control structure.
>>
>>---------------------------------------------------------------------------
>>Jeff Newmiller                        The     .....       .....  Go
>Live...
>>DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live
>Go...
>>                                      Live:   OO#.. Dead: OO#.. 
>Playing
>>Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
>>/Software/Embedded Controllers)               .OO#.       .OO#. 
>rocks...1k
>>---------------------------------------------------------------------------
>
>>Sent from my phone. Please excuse my brevity.
>>
>>On October 9, 2014 10:24:49 PM PDT, PO SU <rhelpmaillist at 163.com>
>wrote:
>>>
>>>Dear expeRts,
>>>   i  use sapply for loop, and i want to break it when i needed, how
>to
>>>do that?  e.g.
>>>
>>>sapply( 1:10, function(i) {
>>>if(i==5) break and jump out of the function sapply
>>>} )
>>>
>>>I want to do it because i have to loop 1000000 times, but i don't
>know
>>>when it will break, that means, it may need break at i=5 or at
>i=50000,
>>>for the possible of the  last case, i don't use for loop, because it
>>>slow(is it right?).
>>>So,if you happen to know it ,may you help me?
>>>
>>>
>>>--
>>>
>>>PO SU
>>>mail: desolator88 at 163.com 
>>>Majored in Statistics from SJTU
>>>______________________________________________
>>>R-help at r-project.org mailing list
>>>https://stat.ethz.ch/mailman/listinfo/r-help
>>>PLEASE do read the posting guide
>>>http://www.R-project.org/posting-guide.html
>>>and provide commented, minimal, self-contained, reproducible code.
>>