Re: [R] Loop problem

From: jim holtman <jholtman_at_gmail.com>
Date: Wed, 26 Mar 2008 10:49:21 -0500

Basically you are moving the data up and then incrementing to the next row. Here is an example; assume that you are at the 2nd entry:

1
2 <== here
3
4

Now your loop index is 2 and you remove the current data ('2') and are left with:

1
3 <== index of 2 points here
4

Now you increment the index to 3 and you get

1
3
4 <== now here

So you have skipped 3. What you should be doing is determining all the index values that meet your criteria and then deleting them all at once, or start from the bottom of the dataframe and work up.

On 3/26/08, Jamie Ledingham <jamie.ledingham_at_newcastle.ac.uk> wrote:
> Dear all, I have a problem with a loop, if anyone has any knowledge on
> these things I would appreciate some comments. The code below is
> designed to allow me to extract the top record of the data frame, and
> them remove rows from the data frame which have an index close to the
> extracted top record.
>
>
> topstorm<-subset(rankeddataset[1,]) ## Extracts the top storm
> topstormindex<-rankeddataset[1,1] ## Finds the top storm start index
> startindex<-topstormindex-48 ## sets the start and end indexes
> endindex<-topstorminde+48
> rankeddataset<-rankeddataset[-1,] ## Creates a new list with the top
> storm removed
>
> ##This section of code needs looped. It removes storms from the list
> which are too close to the extracted storm
>
> for (i in 1:30){
> if (rankeddataset[i,1]>startindex && rankeddataset[i,1]<endindex)
> {rankeddataset<-rankeddataset[-i,]}
> }
>
> Here is some example data:
>
> 82856 15 / 6 / 1966 82856:82879 25.9
> 82857 15 / 6 / 1966 82857:82880 20.5
> 83036 23 / 6 / 1966 83036:83059 17.3
> 87250 15 / 12 / 1966 87250:87273 15.9
>
> The loop does not currently work, it seems to remove every second line
> or so. Can anyone suggest why this might be, I'm not particularly
> experienced in using loops so it may be a rookie mistake. Thanks in
> advance.
> Jamie Ledingham
>
> ______________________________________________
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> 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.
>

-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

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Received on Wed 26 Mar 2008 - 19:27:00 GMT

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