将数据框保存为二进制文件

I would like to save a whole bunch of relatively large data frames while minimizing the space that the files take up. When opening the files, I need to be able to control what names they are given in the workspace.

我想保存一大堆相对较大的数据帧，同时最大限度地减少文件占用的空间。打开文件时，我需要能够控制工作区中给出的名称。

Basically I'm looking for the symantics of dput and dget but with binary files.

基本上我正在寻找dput和dget的语义，但使用二进制文件。

Example:

例：

n<-10000

for(i in 1:100){
    dat<-data.frame(a=rep(c("Item 1","Item 2"),n/2),b=rnorm(n),
        c=rnorm(n),d=rnorm(n),e=rnorm(n))
    dput(dat,paste("data",i,sep=""))
}


##much later


##extract 3 random data sets and bind them
for(i in 1:10){
    nums<-sample(1:100,3)
    comb<-rbind(dget(paste("data",nums[1],sep="")),
            dget(paste("data",nums[2],sep="")),
            dget(paste("data",nums[3],sep="")))
    ##do stuff here
}

2 个解决方案

#1

Your best bet is to use rda files. You can use the save() and load() commands to write and read:

你最好的选择是使用rda文件。您可以使用save（）和load（）命令进行写入和读取：

set.seed(101)
a = data.frame(x1=runif(10), x2=runif(10), x3=runif(10))

save(a, file="test.rda")
load("test.rda")

Edit: For completeness, just to cover what Harlan's suggestion might look like (i.e. wrapping the load command to return the data frame):

编辑：为了完整性，只是为了涵盖Harlan的建议可能是什么样的（即包装load命令以返回数据框）：

loadx <- function(x, file) {
  load(file)
  return(x)
}  

loadx(a, "test.rda")

Alternatively, have a look at the hdf5, RNetCDF and ncdf packages. I've experimented with the hdf5 package in the past; this uses the NCSA HDF5 library. It's very simple:

或者，看看hdf5，RNetCDF和ncdf包。我过去曾尝试过hdf5软件包;这使用NCSA HDF5库。这很简单：

hdf5save(fileout, ...)
hdf5load(file, load = TRUE, verbosity = 0, tidy = FALSE)

A last option is to use binary file connections, but that won't work well in your case because readBin and writeBin only support vectors:

最后一个选项是使用二进制文件连接，但在您的情况下这不会很好，因为readBin和writeBin仅支持向量：

Here's a trivial example. First write some data with "w" and append "b" to the connection:

这是一个简单的例子。首先使用“w”写入一些数据并将“b”附加到连接：

zz <- file("testbin", "wb")
writeBin(1:10, zz)
close(zz)

Then read the data with "r" and append "b" to the connection:

然后用“r”读取数据并在连接中附加“b”：

zz <- file("testbin", "rb")
readBin(zz, integer(), 4)
close(zz)

#2

You may have a look at saveRDS and readRDS. They are functions for serialization.

您可以查看saveRDS和readRDS。它们是序列化的功能。

x = data.frame(x1=runif(10), x2=runif(10), x3=runif(10))

saveRDS(x, file="myDataFile.rds")
x <- readRDS(file="myDataFile.rds")

#1