В Wed, 18 Jun 2025 10:27:37 +
Naresh Gurbuxani пишет:
> mydt <- data.table(
> date = seq(as.IDate("2025-06-01"), by = 1, length.out = 10),
> ABC1_price = runif(10, 100, 120), ABC1_volume = runif(10, 200, 300),
> ABC2_price = runif(10, 100, 120), ABC2_volume = runif(10, 200, 300),
> DEF1_price
Here is a "brute strength and stupidity" approach that may help.
Note I renamed your data.table to DT for my own convenience.
##===##
# Load packages
suppressMessages(library(data.table))
# Load d
I should note that if I have correctly understood your query, paste0 is
vectorized, so you can create vectors of names e.g. by:
nmvec <- paste("a", 1:5)
and then reference these names as needed. I should also add that you may do
better using ?with and/or ?within to access the columns in a data
f
If I understand correctly, see ?"[" : data tables inherit from data frames,
and data frame columns can be indexed by their names as character strings.
The following should give you the idea:
d <- data.frame(a1 = 1:3, a2 = 4:6)
x <- vector("numeric",2)
for(i in 1:2){
nm <- paste0("a",i)
x[i]
My data.table has many columns in groups of four. On each group, I want
to perform the same set of calculations.
mydt <- data.table(
date = seq(as.IDate("2025-06-01"), by = 1, length.out = 10),
ABC1_price = runif(10, 100, 120), ABC1_volume = runif(10, 200, 300),
ABC2_price = runif(10, 100, 120),
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