Hi, R users,
I'm wondering if I can identify an element in a column by an element in
another column. For example:
x-1:10
y-11:20
z-cbind(x,y)
z
x y
[1,] 1 11
[2,] 2 12
[3,] 3 13
[4,] 4 14
[5,] 5 15
[6,] 6 16
[7,] 7 17
[8,] 8 18
[9,] 9 19
[10,] 10 20
What I want to do is:
Is this what you mean?
z[which(z[,x] == 5) - 1, y]
?which is probably what you're looking for...
Hongwei Dong wrote:
Hi, R users,
I'm wondering if I can identify an element in a column by an element in
another column. For example:
x-1:10
y-11:20
z-cbind(x,y)
z
x y
[1,] 1 11
[2,] 2
try this:
x - 1:10
y - 11:20
z - cbind(x, y)
ind - x == 5
z[ind, y] - z[ind, y] - 1
z
I hope it helps.
Best,
Dimitris
On 2/22/2011 6:18 PM, Hongwei Dong wrote:
Hi, R users,
I'm wondering if I can identify an element in a column by an element in
another column. For example:
x-1:10
Hi Gary,
Try
transform(z, y = ifelse(x == 5, y-1, y))
HTH,
Jorge
On Tue, Feb 22, 2011 at 12:18 PM, Hongwei Dong wrote:
Hi, R users,
I'm wondering if I can identify an element in a column by an element in
another column. For example:
x-1:10
y-11:20
z-cbind(x,y)
z
x y
[1,] 1
Hi Gary,
Another possibility besides Erik's (although I suspect his is what you
are really after):
## easier way to data
z - cbind(x = 1:10, y = 11:20)
z[z[,x] == 5, y] - 1
## To see what is going on, break it into pieces
## logical; does column 'x' of 'z' equal 5?
z[, x] == 5
## all values in
Another way is with ifelse:
z-data.frame(x,y)
z$y2 - ifelse(z$x==5,z$y-1,z$y)
HTH,
Ivan
Le 2/22/2011 18:27, Erik Iverson a écrit :
Is this what you mean?
z[which(z[,x] == 5) - 1, y]
?which is probably what you're looking for...
Hongwei Dong wrote:
Hi, R users,
I'm wondering if I can
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