the best,
Patrick
- Original Message -
From: Liaw, Andy [EMAIL PROTECTED]
To: 'Patrick Giraudoux' [EMAIL PROTECTED]; r-help
[EMAIL PROTECTED] Sent: Saturday, October 09, 2004 3:00 PM
Subject: RE: [R] which() and value replacement in a matrix
Use the index vector directly, rather
Hi,
I cannot go through the archives with which() as key-word... so common. Though I am
sure to have seen something about this subject
in the past could somebody put me on the track. I have a matrix (actually a
data.frame) in which I would replace the non-null values
by 1.
I tried the
Use the index vector directly, rather than breaking it up:
x - matrix(sample(30), 10, 3)
idx - which(x 25, arr.ind=TRUE)
idx
row col
[1,] 6 1
[2,] 9 1
[3,] 4 2
[4,] 6 2
[5,] 4 3
x[idx] - 999
x
[,1] [,2] [,3]
[1,]7 14 16
[2,] 20 248
[3,] 17
() and value replacement in a matrix
Use the index vector directly, rather than breaking it up:
x - matrix(sample(30), 10, 3)
idx - which(x 25, arr.ind=TRUE)
idx
row col
[1,] 6 1
[2,] 9 1
[3,] 4 2
[4,] 6 2
[5,] 4 3
x[idx] - 999
x
[,1] [,2] [,3
]
Sent: Saturday, October 09, 2004 3:00 PM
Subject: RE: [R] which() and value replacement in a matrix
Use the index vector directly, rather than breaking it up:
x - matrix(sample(30), 10, 3)
idx - which(x 25, arr.ind=TRUE)
idx
row col
[1,] 6 1
[2,] 9 1
[3,] 4
