Could I easily drop column of ffdf
object ?
library(ff);library(ffbase)
irisdf=as.ffdf(iris)
How to contain only Sepal.length
and Species
columns ?
You could try subset
from ffbase
library(ffbase)
Subiris <- subset(irisdf, select=c('Sepal.Length', 'Species'))
dim(Subiris)
#[1] 150 2
colnames(Subiris)
#[1] "Sepal.Length" "Species"
library(ff)
irisdf <- as.ffdf(iris)
filename(irisdf)
## Referencing the same data on disk (just making an new virtual ffdf)
example1 <- irisdf[setdiff(colnames(irisdf), c("Sepal.Length", "Species"))]
filename(example1)
## Referencing new data (copying)
example2 <- clone(irisdf[setdiff(colnames(irisdf), c("Sepal.Length", "Species"))])
filename(example2)
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.