On Apr 10, 2012, at 1:08 PM, Steve Lavrenz wrote:

I definitely need a loop - the example I gave was only a simple one. Say I want to do more complex calculations in each step, such that the numeric
difference between consecutive terms is not constant.

You can always use:
for( i in  seq(0,100, by=5) ){
             ....stuff... }

seq_along() creates an integer index from a vector. It avoids potenial problems with
    for( i in 1:length(vec) ) {   }


-Steve



From: Jean V Adams [mailto:jvad...@usgs.gov]
Sent: Tuesday, April 10, 2012 12:38 PM
To: Steve Lavrenz
Cc: r-help@r-project.org
Subject: Re: [R] Creating a loop with an indefinite end term




Do you need a loop at all?

Will this do the trick?

seq(from=0, to=100, by=5)

Jean


Steve Lavrenz wrote on 04/10/2012 09:48:34 AM:

Everyone,

I'm very new to R, especially when it comes to loops and functions, so please bear with me if this is an elementary question. I cannot seem to figure out how to construct a loop which runs a function until a certain
value is computed. For example, say I have the following:

num = numeric (10)
num [1] = 0
for (i in 2:10)   {
     num [i] = num [i-1] + 5
}

This adds 5 to the preceding spot of a vector of length 10 to get the
value
in the current spot. However, say I don't just want to run this for 10
spots; rather I want to run it until a certain value (say, 100) is
computed.
How I construct my loop to do this?

Thanks!


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