Re: [R] replace numbers in a column conditional on their value
Splendid, thanks for your quick response.
[EMAIL PROTECTED] wrote: I have a data frame column in which I would like to
replace some
of the numbers dependent on their value.
data frame = zz
AveExpr t P.Value FC
7.481964 7.323950 1.778503e-04 2.218760
7.585783 12.233056 6.679776e-06 2.155867
6.953215 6.996525 2.353705e-04 1.685733
7.647513 8.099859 9.512639e-05 1.674742
7.285446 7.558675 1.463732e-04 1.584071
6.405605 3.344031 1.276812e-02 1.541569
I would like to replace the values in column 'FC' which are 2
with their squared value.
If I do this, however, I get a warning but it does the sum correctly.
Warning message:
number of items to replace is not a multiple of replacement length
in: zz[, 4][zz[, 4] 2] - zz[, 4]^2
Try
zz$FC[zz$FC 2] - (zz$FC[zz$FC 2])^2
Regards,
Richie.
Mathematical Sciences Unit
HSL
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[R] replace numbers in a column conditional on their value
Dear R help, I have a data frame column in which I would like to replace some of the numbers dependent on their value. data frame = zz AveExpr t P.Value FC 7.481964 7.323950 1.778503e-04 2.218760 7.585783 12.233056 6.679776e-06 2.155867 6.953215 6.996525 2.353705e-04 1.685733 7.647513 8.099859 9.512639e-05 1.674742 7.285446 7.558675 1.463732e-04 1.584071 6.405605 3.344031 1.276812e-02 1.541569 I would like to replace the values in column 'FC' which are 2 with their squared value. If I do this, however, I get a warning but it does the sum correctly. Warning message: number of items to replace is not a multiple of replacement length in: zz[, 4][zz[, 4] 2] - zz[, 4]^2 Is there a way to do this without the warning? - [[alternative HTML version deleted]] __ R-help@r-project.org 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.
Re: [R] replace numbers in a column conditional on their value
Try something like, ##Untested zz$FC - ifelse(zz$FC 2, zz$FC^2, zz$FC) and see ?ifelse -Erik Iverson Jabez Wilson wrote: Dear R help, I have a data frame column in which I would like to replace some of the numbers dependent on their value. data frame = zz AveExpr t P.Value FC 7.481964 7.323950 1.778503e-04 2.218760 7.585783 12.233056 6.679776e-06 2.155867 6.953215 6.996525 2.353705e-04 1.685733 7.647513 8.099859 9.512639e-05 1.674742 7.285446 7.558675 1.463732e-04 1.584071 6.405605 3.344031 1.276812e-02 1.541569 I would like to replace the values in column 'FC' which are 2 with their squared value. If I do this, however, I get a warning but it does the sum correctly. Warning message: number of items to replace is not a multiple of replacement length in: zz[, 4][zz[, 4] 2] - zz[, 4]^2 Is there a way to do this without the warning? - [[alternative HTML version deleted]] __ R-help@r-project.org 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. __ R-help@r-project.org 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.
Re: [R] replace numbers in a column conditional on their value
I have a data frame column in which I would like to replace some
of the numbers dependent on their value.
data frame = zz
AveExpr t P.Value FC
7.481964 7.323950 1.778503e-04 2.218760
7.585783 12.233056 6.679776e-06 2.155867
6.953215 6.996525 2.353705e-04 1.685733
7.647513 8.099859 9.512639e-05 1.674742
7.285446 7.558675 1.463732e-04 1.584071
6.405605 3.344031 1.276812e-02 1.541569
I would like to replace the values in column 'FC' which are 2
with their squared value.
If I do this, however, I get a warning but it does the sum correctly.
Warning message:
number of items to replace is not a multiple of replacement length
in: zz[, 4][zz[, 4] 2] - zz[, 4]^2
Try
zz$FC[zz$FC 2] - (zz$FC[zz$FC 2])^2
Regards,
Richie.
Mathematical Sciences Unit
HSL
ATTENTION:
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R-help@r-project.org mailing list
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Re: [R] replace numbers in a column conditional on their value
On 17/01/2008, at 5:45 AM, Jabez Wilson wrote:
Dear R help,
I have a data frame column in which I would like to replace some
of the numbers dependent on their value.
data frame = zz
AveExpr t P.Value FC
7.481964 7.323950 1.778503e-04 2.218760
7.585783 12.233056 6.679776e-06 2.155867
6.953215 6.996525 2.353705e-04 1.685733
7.647513 8.099859 9.512639e-05 1.674742
7.285446 7.558675 1.463732e-04 1.584071
6.405605 3.344031 1.276812e-02 1.541569
I would like to replace the values in column 'FC' which are 2
with their squared value.
If I do this, however, I get a warning but it does the sum
correctly.
Warning message:
number of items to replace is not a multiple of replacement length
in: zz[, 4][zz[, 4] 2] - zz[, 4]^2
Is there a way to do this without the warning?
Other replies have suggested a better way to do this, but have not
made it clear
what you are doing wrong. The problem is that in your example you
are effectively
trying to replace 2 values with a vector of length 6 (i.e. zz[,4]
^2). This will
use the first two values of the vector of length 6 to replace the two
values that
you've chosen to replace.
This ``works'' in your example since your two values to be replaced
come first in
the column. But it *won't* work in general, warning message or no
warning message.
E.g.
zz - data.frame(x=1:6,y=1:6,z=1:6,w=c(1,2,3,3,2,1))
zz
x y z w
1 1 1 1 1
2 2 2 2 2
3 3 3 3 3
4 4 4 4 3
5 5 5 5 2
6 6 6 6 1
R zz[,4][zz[,4]2] - zz[,4]^2
Warning message:
In zz[, 4][zz[, 4] 2] - zz[, 4]^2 :
number of items to replace is not a multiple of replacement length
zz
x y z w
1 1 1 1 1
2 2 2 2 2
3 3 3 3 1
4 4 4 4 4
5 5 5 5 2
6 6 6 6 1
The two values (3rd and 4th) to be replaced got replaced by 1 and 4
--- the squares
of the first two entries of the column.
Moral of the story: ***DON'T SUPPRESS WARNINGS***!!! ***HEED
THEM***!!!
The use of ifelse that others have suggested is the right way to go.
But
you could do what you want using a syntax similar to that which you
indeed used,
but corrected as follows:
zz - data.frame(x=1:6,y=1:6,z=1:6,w=c(1,2,3,3,2,1))
zz[,4][zz[,4]2] - zz[,4][zz[,4]2]^2 # See the difference?
zz
x y z w
1 1 1 1 1
2 2 2 2 2
3 3 3 3 9
4 4 4 4 9
5 5 5 5 2
6 6 6 6 1
cheers,
Rolf Turner
##
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