**From:** Christoph Scherber (*Christoph.Scherber@uni-jena.de*)

**Date:** Wed 05 May 2004 - 00:20:06 EST

**Next message:**Adaikalavan Ramasamy: "Re: [R] more on lm(y~x) question: removing NA´s"**Previous message:**Thomas Lumley: "Re: [R] RE: more on lm(y~x) question: removing NA´s"**In reply to:**Thomas Lumley: "Re: [R] RE: more on lm(y~x) question: removing NA´s"**Next in thread:**Thomas Lumley: "Re: Re: [R] RE: more on lm(y~x) question: removing NA´s"**Reply:**Thomas Lumley: "Re: Re: [R] RE: more on lm(y~x) question: removing NA´s"

Message-id: <4097A696.6070205@uni-jena.de>

it all works fine (the regression lines fit correctly to the data) as

long as there are not both missing values in j and k.

What suggestions would you have for this? Or, more precisely, how would

you create multiple graphs from subsequent columns of a data.frame?

Thomas Lumley wrote:

*>On Tue, 4 May 2004, Liaw, Andy wrote:
*

*>
*

*>
*

*>
*

*>>1. If your code actually runs, you should upgrade R, and quit using `_' for
*

*>>assignment... 8-)
*

*>>
*

*>>2. You seem to have an extraneous `]' after the na.exclude. Could that be
*

*>>the problem?
*

*>>
*

*>>
*

*>
*

*>More seriously, the for() loop over k will mess up the value of k that you
*

*>want to use for lm.
*

*>
*

*> -thomas
*

*>
*

*>
*

*>
*

*>
*

*>>Andy
*

*>>
*

*>>
*

*>>
*

*>>
*

*>>>From: Christoph Scherber
*

*>>>
*

*>>>actually, the situation is much more complicated. I am producing
*

*>>>multiple graphs within a "for" loop. For some strange reason, the
*

*>>>plotting routine always stops once lm(y~x) encounters more than one
*

*>>>missing value (I have marked the important bit with "***********"):
*

*>>>
*

*>>>par(mfrow=c(5,5))
*

*>>>p_seq(3,122,2)
*

*>>>i_0
*

*>>>k_0
*

*>>>number_0
*

*>>>for (i in p) {
*

*>>> j_foranalysis[93:174,i+1]
*

*>>> k_foranalysis[93:174,i]
*

*>>> df_data.frame(j,k)
*

*>>> mainlab1_substring(names(foranalysis[i]),2,8)
*

*>>> mainlab2_"; corr.:"
*

*>>> mainlab3_round(cor(j,k,na.method="available"),4)
*

*>>> mainlab4_"; excl.Mono:"
*

*>>> mainlab5_round(cor(j[j<0.9],k[j<0.9],na.method="available"),4)
*

*>>> mainlab_paste(mainlab1,mainlab2,mainlab3,mainlab4,mainlab5)
*

*>>> plot(k,j,main=mainlab,xlab="% of total biomass",ylab="% of total
*

*>>>cover",pch="n")
*

*>>> for (k in 1:length(foranalysis[93:174,i]))
*

*>>>number[k]_substring(plotcode[foranalysis[k,1]],1,5)
*

*>>> text(foranalysis[93:174,i],foranalysis[93:174,i+1],number)
*

*>>>**********************************
*

*>>> model_lm(j~k,na.action=na.exclude])
*

*>>>**********************************
*

*>>> abline(model)
*

*>>> abline(0,1,lty=2)
*

*>>> }
*

*>>>
*

*>>>Does anyone have any suggestions on this?
*

*>>>
*

*>>>Best regards
*

*>>>Chris.,
*

*>>>
*

*>>>
*

*>>>
*

*>>>
*

*>>>Liaw, Andy wrote:
*

*>>>
*

*>>>
*

*>>>
*

*>>>>By (`factory') default that's done for you automagically, because
*

*>>>>options("na.action") is `na.omit'.
*

*>>>>
*

*>>>>If you really want to do it `by hand', and have the data in
*

*>>>>
*

*>>>>
*

*>>>a data frame,
*

*>>>
*

*>>>
*

*>>>>you can use something like:
*

*>>>>
*

*>>>>lm(y ~ x, df[complete.cases(df),])
*

*>>>>
*

*>>>>HTH,
*

*>>>>Andy
*

*>>>>
*

*>>>>
*

*>>>>
*

*>>>>
*

*>>>>
*

*>>>>>From: Christoph Scherber
*

*>>>>>
*

*>>>>>Dear all,
*

*>>>>>
*

*>>>>>I have a data frame with different numbers of NA´s in each
*

*>>>>>column, e.g.:
*

*>>>>>
*

*>>>>>x y
*

*>>>>>1 2
*

*>>>>>NA 3
*

*>>>>>NA 4
*

*>>>>>4 NA
*

*>>>>>1 5
*

*>>>>>NA NA
*

*>>>>>
*

*>>>>>
*

*>>>>>I now want to do a linear regression on y~x with all the NA´s
*

*>>>>>removed.
*

*>>>>>The problem now is that is.na(x) (and is.na(y) obviously
*

*>>>>>gives vectors
*

*>>>>>with different lengths. How could I solve this problem?
*

*>>>>>
*

*>>>>>Thank you very much for any help.
*

*>>>>>
*

*>>>>>Best regards
*

*>>>>>Chris
*

*>>>>>
*

*>>>>>
*

*>>>>>
*

*>>______________________________________________
*

*>>R-help@stat.math.ethz.ch mailing list
*

*>>https://www.stat.math.ethz.ch/mailman/listinfo/r-help
*

*>>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
*

*>>
*

*>>
*

*>>
*

*>
*

*>Thomas Lumley Assoc. Professor, Biostatistics
*

*>tlumley@u.washington.edu University of Washington, Seattle
*

*>
*

*>
*

*>
*

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**Next message:**Adaikalavan Ramasamy: "Re: [R] more on lm(y~x) question: removing NA´s"**Previous message:**Thomas Lumley: "Re: [R] RE: more on lm(y~x) question: removing NA´s"**In reply to:**Thomas Lumley: "Re: [R] RE: more on lm(y~x) question: removing NA´s"**Next in thread:**Thomas Lumley: "Re: Re: [R] RE: more on lm(y~x) question: removing NA´s"**Reply:**Thomas Lumley: "Re: Re: [R] RE: more on lm(y~x) question: removing NA´s"

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