Re: truncate dataset

[<Rich@Mango-Solutions.com>]

Hi Keith

How about something like this:

> # I assume my dataset is called "df" in this example

> sRow <- seq(nrow(df))

> df[sRow > quantile(sRow, .2) & sRow < quantile(sRow, .8), ]

Hope this helps,

Rich.

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-----Original Message-----
From: theforester@comcast.net [mailto:theforester@comcast.net]
Sent: 21 February 2007 16:58
To: s-news@lists.biostat.wustl.edu
Subject: [S] truncate dataset

All,

I am trying to eliminate the effects of age upon my analysis of growth vs category.  I have two categories and, for each, I would like to truncate the top 20% and the bottom 20% of the data subset.

Two categories: A & B

Dependent var: growth

Independent var: measures of mixture

The number of elements in each category is not the same.  Also, the distribution of category A is not necessarily the same as the distribution of category B;  e.g., the bottom 20% of A, for example, would not necessarily be the same age as the bottom 20% of B.

Does anyone have suggestions about the syntax for extracting or subsetting the dataset to only look at the middle 60% of each category?

I couldn't find anything in the archives, but perhaps my search keywords were not correct.

Thank you in advance.

Keith

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