[R] subsets

[Ivan Calandra]

Hi!

I think you should read the intro to R, as well as ?"[" and ?subset. It 
should help you to understand.

Let's say your data is in a data.frame called df:
# 1. ah and ihd
df_ah_ihd <- df[df$diagnosis=="ah" | df$diagnosis=="ihd", ]  ## the "|" 
is the boolean OR (you want one OR the other). Note the last comma

#2. ah
df_ah <- df[df$diagnosis=="ah", ]

#3. ihd
df_ihd <- df[df$diagnosis=="ihd", ]

You could do the same using subset() if you feel better with this function.

HTH,
Ivan

Le 1/20/2011 09:53, Den a écrit :
> Dear R people
> Could you please help.
>
> Basically, there are two variables in my data set. Each patient ('id')
> may have one or more diseases ('diagnosis'). It looks like
>
> id	diagnosis
> 1	ah
> 2	ah
> 2	ihd
> 2	im
> 3	ah
> 3	stroke
> 4	ah
> 4	ihd
> 4	angina
> 5	ihd
> ..............
> Q: How to make three data sets:
> 	1. Patients with ah and ihd
>   	2. Patients with ah but no ihd
> 	3. Patients with  ihd but no ah?
>
>   If you have any ideas could just guide what should I look for. Is a
> subset or aggregate, or loops, or something else??? I am a bit lost. (F1
> F1 F1 !!!:)
> Thank you
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. Säugetiere
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calandra at uni-hamburg.de

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