Hi Edward,
In your post, rather than asking for the indexes, you asked for the numbers,
AFAICS. Now, whether you want the indexes in which (b-a) is either positive
or negative, then do
which(b-a>0) # Positives
# [1] 2 3 6 7
which(b-a<0) # Negatives
# [1] 1 4 5
(a-b)[b<a] # Henrique's solution to what you asked first
# [1] 1 3 1
Am I missing something here? Could be :-)
HTH,
Jorge
On Mon, Sep 14, 2009 at 5:14 PM, <edche...@gmail.com> wrote:
> thank you all for your help. I do know how to use which() but my problem
> is that I am writing a function in which this is just part of it. After
> seeing the (a-b)[b<a], it gives the wrong index number for which is negative
> and which is positive. I am not sure why that is, but the which function
> does give the correct index number. I guess what I want is to be able to
> save two vectors of index and use them to reference the raw data base for
> further calculation. One vector for all the negative values and one for all
> the positive ones.
>
>
> Edward Chen
> Email: tke...@msn.com
> Cell Phone: 510-371-4717
>
>
>
>
> ------------------------------
> From: www...@gmail.com
> Date: Mon, 14 Sep 2009 16:35:23 -0300
> Subject: Re: [R] Help with for loop
> To: dwinsem...@comcast.net
> CC: jorgeivanve...@gmail.com; r-help@r-project.org; edche...@gmail.com
>
>
> Or:
>
> (a - b)[b < a]
>
> On Mon, Sep 14, 2009 at 4:16 PM, David Winsemius
> <dwinsem...@comcast.net>wrote:
>
>
> On Sep 14, 2009, at 3:02 PM, Jorge Ivan Velez wrote:
>
> Hi Edward,
> Here is a suggestion:
>
> a = c(4,5,1,7,8,12,39)
> b = c(3,7,8,4,7,25,78)
> d <- a-b
> d[which(d>0)]
> # [1] 1 3 1
>
>
> #Or even:
> d <- (a-b)[which((a-b)>0)]
> d
> #[1] 1 3 1
>
>
>
> HTH,
> Jorge
>
>
> On Mon, Sep 14, 2009 at 2:50 PM, Edward Chen <edche...@gmail.com> wrote:
>
> I have a code:
> *a = c(4,5,1,7,8,12,39)
> b = c(3,7,8,4,7,25,78)
> d =a-b
> for(i in 1:length(d)){
> if(d[i]>0){x = list(d[i])
> print(x)}
> else{y = list(d[i])
> print(y)}}
>
> the results are:
>
> [[1]]
> [1] 1
>
> [[1]]
> [1] -2
>
> [[1]]
> [1] -7
>
> [[1]]
> [1] 3
>
> [[1]]
> [1] 1
>
> [[1]]
> [1] -13
>
> [[1]]
> [1] -39
>
>
> which will tell me what d is. but is it possible to output the order in
> which the difference is in the vector d?
> for example I would want to see x = 1,3,1 and they are from d[1], d[4],
> d[5].
> This is just a crude example I thought of to help me do something more
> complicated.
>
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
>
> ______________________________________________
> R-help@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.
>
>
>
>
> --
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
>
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