# Re: [R] Vector DF [a, b] to replace values :was Finding the position of a variable in a data.frame

From: John Kane <jrkrideau_at_yahoo.ca>
Date: Thu 03 Aug 2006 - 22:42:03 EST

> ?which
>
> > which(Df >= 50, arr.ind=T)
> row col
> 5 5 4

This works very nicely as has some other suggestions on how to replace a value. Assuming that I have more than one correction to make where Df >= 50, can I use vectors in the Df[] to do this.

My attempt shows that I can use vectors but it appears thatthere is something wrong with my logic

Eample

```cat <- c( 3,5,6,8,0)
dog <- c(3,5,3,6, 0)
rat <- c (5, 5, 4, 9, 51)
bat <- c( 12, 42, 45, 32, 54)

```

Df <- data.frame(cbind(cat, dog, rat, bat)) post <- which(Df >= 50, arr.ind=T) # find values .= 50
post
correction <- c(77, 88) # new correct values

```row <- post[ ,1]      # vector for row number
col <- post[ ,2]       # vector for column number

```

Df[row,col] <- correction
Df

-------result---------
cat dog rat bat
1 3 3 5 12
2 5 5 5 42
3 6 3 4 45
4 8 6 9 32
5 0 0 88 88

I am replacing both instances with 88 which is not correct

Thanks

> On 8/2/06, John Kane <jrkrideau@yahoo.ca> wrote:
> >
> > Simple problem but I don't see the answer. I'm
> trying
> > to clean up some data
> > I have 120 columns in a data.frame. I have one
> value
> > in a column named "blaw" that I want to change.
> How do
> > I find the coordinates. I can find the row by
> doing a
> > subset on the data.frame but how do I find out
> here
> > "blaw " is in columns without manually counting
> them
> > or converting names(Df) to a list and reading down
> the
> > list.
> >
> > Simple example
> >
> > cat <- c( 3,5,6,8,0)
> > dog <- c(3,5,3,6, 0)
> > rat <- c (5, 5, 4, 9, 0)
> > bat <- c( 12, 42, 45, 32, 54)
> >
> > Df <- data.frame(cbind(cat, dog, rat, bat))
> > Df
> > subset(Df, bat >= 50)
> >
> > ----results
> > cat dog rat bat
> > 5 0 0 0 54
> >
> >
> > Thus I know that my target is in row 5 but how do
> I
> > figure out where 'bat' is?
> >
> > All I want to do is be able to say
> > Df[5,4] <- 100
> >
> > Is there some way to have function(bat) return the
> > column number: some kind of a colnum() function?
> I
> > had thought that I had found somthing in
> > library(gdata) matchcols but no luck.
> >
> > ______________________________________________
> > R-help@stat.math.ethz.ch mailing list
> > 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?
>

R-help@stat.math.ethz.ch mailing list
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. Received on Thu Aug 03 22:47:25 2006

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