How to subset a large data frame (ffdf) in R by date?
2014年4月9日 · Use subset.ffdf from package ffbase. Subset is a generic function in R, and ffbase implements it for ffdf objects. So you can just use subset as you would do with a regular data …
Reading a csv file using ffdf and subsetting it successfully
2012年9月18日 · Trying to learn about ffdf output, I entered command lines such as dim(B2010), str(B2010), ls(B2010), etc. dim(B2010) resulted in the appropriate number of rows but only …
r - Merging and appending ffdf dataframes - Stack Overflow
I am trying to create an ffdf dataframe by merging and appending two existing ffdf dataframes. The ffdfs have different numbers of columns and different row numbers. I know that merge() …
ff - Subsetting ffdf objects in R - Stack Overflow
2014年3月3日 · The package ffbase provides many base functions for ff/ffdf objects, including subset.ff. With a bit of limited testing, it seems that subset.ff is relatively fast. Try loading …
r - na.locf() for an FFDF - Stack Overflow
2015年7月23日 · I have a very large data set that I have to use as an ffdf, and am stuck trying to fill NA values using a last observation carried forward operation. Below is a sample of what the …
rbinding two ffdf data frames in R - Stack Overflow
2012年8月13日 · use ffdfappend from version 0.6 of the ffbase package. The ffdfappend of version 0.5 was designed to append a data.frame to an ffdf, while the one from version 0.6 …
r - How to cast ffdf to ff - Stack Overflow
2014年3月3日 · But I assume you have a ffdf with all columns of the same type, otherwise it does not make sense to convert it to an ff vector or ff matrix. If you want to convert to an ff matrix, …
r - Why does ff still store data in RAM? - Stack Overflow
2013年2月22日 · If you pass a ffdf object instead of a data.frame, you run into one of the following two problems: ffdf is not a data.frame, so something undefined happens; the function to which …
How can you apply a function or logical test to a ffdf?
2014年8月19日 · This is basically asking how to apply a previous question to a ffdf : R - applying ifelse to a whole data frame. I am basically trying to do the same thing. Given a ffdf dataframe, …
r - Loading ffdf data take a lot of memory - Stack Overflow
2012年12月19日 · data <- read.csv.ffdf(file = fn, header = T, colClasses = classes) # file fn is a csv database with 5 columns and 2.6 million rows, # with some factor cols and some integer …