Displaying 5 results from an estimated 5 matches for "sdcol".
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dcol
2024 Sep 28
1
lattice xyplot with cumsum() function inside
...ate("2024-01-01"), by = 1,
length.out = 50), xgroup = "A", x = runif(50, 0, 1))
mydt <- rbindlist(list(mydt, data.table(date = mydt$date, xgroup = "B", x = runif(50, 0, 3))))
mydt[, `:=`(xcumsum = cumsum(x)), by = .(xgroup)]
mydt[, lapply(.SD, sum), by = .(xgroup), .SDcols = c("x")]
# xgroup x
# <char> <num>
#1: A 26.00455
#2: B 71.55405
#For xgroup = "B", line starts at the sum of all previous x values
including xgroup = "A"
#Intended result is to separate cumsum(x) for groups "A" and &quo...
2002 May 11
1
deleting invariant rows and cols in a matrix
...stp != 1){
stp.row <- rep(0,nrow(clean))
stp.col <- rep(0,ncol(clean))
# Start with rows
for (i in 1:nrow(clean)){
sdrow <- sd(clean[i,])
if (sdrow==0) clean <- clean[i * -1,]
if (sdrow==0) stp.row[i] <- 1
}
# Next check columns
for (j in 1:ncol(clean)){
sdcol <- sd(clean[,j])
if (sdcol==0) clean <- clean[,j * -1]
if (sdcol==0) stp.col[j] <- 1
}
# Do we need to continue with the process?
if (sum(stp.row)==0 && sum(stp.col)==0) stp <- 1
}
# Output cleaned data to new dataset name
cleaned <<- clean
}
---- end R c...
2020 Sep 24
1
How to use `[` without evaluating the arguments.
...which(colnames(colData) %in% colIDs)
lockBinding('colIDs', internals)
# Assemble the pseudo row and column names for the LongTable
.pasteColons <- function(...) paste(..., collapse=':')
rowData[, `:=`(.rownames=mapply(.pasteColons, transpose(.SD))), .SDcols=internals$rowIDs]
colData[, `:=`(.colnames=mapply(.pasteColons, transpose(.SD))), .SDcols=internals$colIDs]
return(.LongTable(rowData=rowData, colData=colData,
assays=assays, metadata=metadata,
.intern=internals))
}
I have also defined a subset...
2013 Mar 13
3
loop in a data.table
Hi everyone,
I have a data.table called "data" with many columns which I want to
group by column1 using data.table, given how fast it is.
The problem with looping a data.table is that data.table does not like
quotations to define the column names (e.g. "col2" instead of col2).
I found a way around which is to use get("col2"), which works fine but
the
2012 Sep 14
3
aggregate() runs out of memory
I have a large data.frame Z (2,424,185,944 bytes, 10,256,441 rows, 17 columns).
I want to get the result of
table(aggregate(Z$V1, FUN = length, by = list(id=Z$V2))$x)
alas, aggregate has been running for ~30 minute, RSS is 14G, VIRT is
24.3G, and no end in sight.
both V1 and V2 are characters (not factors).
Is there anything I could do to speed this up?
Thanks.
--
Sam Steingold