Message-ID: <52886C56.8050905@bitwrit.com.au>
Date: 2013-11-17T07:12:22Z
From: Jim Lemon
Subject: Calculate Range
In-Reply-To: <1384638589297-4680579.post@n4.nabble.com>
On 11/17/2013 08:49 AM, SCRIPTHAM wrote:
> Hi
>
> My R version is the current version as at 15 Nov 2013.
>
> I have tried to calculate range using tapply() with FUN=range.
> tapply() returns two fields, the ID field and a field of two text items one
> is the maximum and the other is the minimum.
> I take as the difference max - min, does R use a different term for range in
> tapply?
>
> I have also tried
> aggregate() with Fun=range, with Fun=min and FUN=max
> and they also gave problems.
>
> What is the best route to calculate ranges for groups within a data frame.
>
Hi Scriptham,
It looks like you want to get the difference between the maximum and
minimum values rather than the actual values. Define a function:
range_span<-function(x) return(diff(range(x)))
and use that as the FUN argument.
Jim