Columnbind ff data frames in R

问题:

i try to work with the ff package. In this context i try to cbind two ff dataframes. I found a solution to combine a ffdf with a ff vector but how do i combine to ffdf. Here my code for combining ffdf with ff vector:

library(ff)
## read Bankfull flow##
setwd(wd)
bf <- read.csv.ffdf(file="G_BANKFULL_km3month.csv",header=TRUE)
## read river discharge global, monthly vlaues 1971-2000##
memory.limit(size=16000)   # increase working memory
dis <- read.table.ffdf(file='RIVER_AVAIL_7100_WG22.txt', header=T, sep="\t", dec=".")
##read bankfull values as ff object##
bfvalues <- ff(bf[,2])
##combination of bf and dis ( see test <- cbind(dis,bf$VALUE))
dis_bf <- do.call('ffdf', c(physical(dis), list(bfvalues=bfvalues)))

Thanks a lot for your help

回答1:

Question has been answered here: How to column bind two ffdf

library(ff)
ff1 <- as.ffdf(data.frame(letA = letters[1:5], numA = 1:5))
ff2 <- as.ffdf(data.frame(letB = letters[6:10], numB = 6:10))

cbind.ffdf2 <- function(d1, d2){
D1names <- colnames(d1)
D2names <- colnames(d2)
mergeCall <- do.call("ffdf", c(physical(d1), physical(d2)))
colnames(mergeCall) <- c(D1names, D2names)
mergeCall
}

cbind.ffdf2(ff1, ff2)[,]