Hi Andre,
A slight correction:
fun1 <- function(beginColumn, by, data) {
indx <- seq(beginColumn, ncol(data), by = by)
dataNew <- data[, indx[1]:ncol(data)]
indx1 <- cumsum(seq(ncol(data)) %in% indx)
indx2 <- indx1[indx1 != 0]
lst1 <- lapply(split(seq_along(indx2), indx2), function(i) {
x1 <- dataNew[, i, drop = FALSE]
if (ncol(x1) > 1) {
x1[, -1, drop = FALSE]/mean(x1[, 1]) ###changed
}
})
res <- data.frame(lst1[sapply(lst1, length) > 0])
colnames(res) <- gsub(".*\\.", "", colnames(res))
res
}
Also, you can try:
fun2 <- function(beginColumn, by, data) {
indx <- seq(beginColumn, ncol(data), by = by)
indx1 <- head(indx + 1, -1)
indx2 <- tail(indx - 1, -1)
vec1 <- as.vector(sapply(seq_along(indx1), function(i) indx1[i]:indx2[i]))
if (ncol(data) > tail(indx, 1)) {
vec2 <- c(vec1, (tail(indx, 1) + 1):ncol(dat1))
} else {
vec2 <- vec1
}
means1 <- rep(colMeans(data[, indx]), each = by - 1, length.out =
length(vec2))
res <- as.data.frame(t(t(data[, vec2])/means1))
res
}
set.seed(458)
dat1 <- as.data.frame(matrix(sample(5,10*5,replace=TRUE),ncol=10))
identical(fun1(2,4,dat1),fun2(2,4,dat1))
#[1] TRUE
A.K.
Hi,
May be this helps:
fun1 <- function(beginColumn, by, data) {
indx <- seq(beginColumn, ncol(data), by = by)
dataNew <- data[, indx[1]:ncol(data)]
indx1 <- cumsum(seq(ncol(data)) %in% indx)
indx2 <- indx1[indx1 != 0]
lst1 <- lapply(split(seq_along(indx2), indx2), function(i) {
x1 <- dataNew[, i, drop = FALSE]
if (ncol(x1) > 1) {
x1[, -1]/mean(x1[, 1])
}
})
res <- data.frame(lst1[sapply(lst1, length) > 0])
colnames(res) <- gsub(".*\\.", "", colnames(res))
res
}
set.seed(458)
dat1 <- as.data.frame(matrix(sample(5,10*5,replace=TRUE),ncol=10))
set.seed(34)
dat2 <- as.data.frame(matrix(sample(20,21*5,replace=TRUE),ncol=21))
fun1(2,4,dat1)
fun1(2,5,dat2)
A.K.
On Sunday, April 20, 2014 5:55 AM, Andre Zacharia <andre.zacha...@gmail.com>
wrote:
Dear all,
I am getting data columnwise that I need to divide by the mean of another
column
If the column is the previous one this code works perfectly well:
fun1 <- function(beginColumn, by, data) { indx <- seq(beginColumn,
ncol(data), by = by) as.data.frame(t(100 - (t(data[, indx])/colMeans(data[,
indx - 1], na.rm = TRUE)) * 100))
}
(Arun helped me with this code, thank you again!...)
But, the things is now more complicated...
I need to program a function that allow me to divide for example cells from
column 3 on mean from column 2 and cells from column 4 on mean of column 2
and the 5 etc. Then column 6 is another column from whch I need to extract
the mean and to do the same with column 7 and 8, etc...
so if I have:
1 2 3 4 1 5
2 5 4 7 2 8
3 4 5 9 3 7
4 7 7 9 4 3
The serie 1,2,3,4 ar just enumerating so not useful at this timepoint.
the results should be (from excel...):
4,5 33,3333333 11,1111111 -11,1111111 11,1111111 -55,5555556 -77,7777778
-11,1111111 -100 -55,5555556 -55,5555556 -100
33,3333333
I tried to work on modyfying indx-1 by 2*indx-2, but this is not doing the
job... I tried many other things so that I am now stucked.
Does Anyone has a brilliant idea?
Many many thanks
André ZACHARIA
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