R语言实现二进制文件读写操作

writeBin(object, con)
readBin(con, what, n )

#my first R program
 
# Read the "mtcars" data frame as a csv file and store only the columns "cyl", "am" and "gear".
write.table(mtcars, file = "mtcars.csv",row.names = FALSE, na = "", 
  col.names = TRUE, sep = ",")
 
# Store 5 records from the csv file as a new data frame.
new.mtcars <- read.table("mtcars.csv",sep = ",",header = TRUE,nrows = 5)
 
# Create a connection object to write the binary file using mode "wb".
write.filename = file("D:/r_file/binmtcars.dat", "wb")
 
# Write the column names of the data frame to the connection object.
writeBin(colnames(new.mtcars), write.filename)
 
# Write the records in each of the column to the file.
writeBin(c(new.mtcars$cyl,new.mtcars$am,new.mtcars$gear), write.filename)
 
# Close the file for writing so that it can be read by other program.
close(write.filename)

#my first R program
 
# Create a connection object to read the file in binary mode using "rb".
read.filename <- file("D:/r_file/binmtcars.dat", "rb")
 
# First read the column names. n = 3 as we have 3 columns.
column.names <- readBin(read.filename, character(), n = 3)
 
# Next read the column values. n = 18 as we have 3 column names and 15 values.
read.filename <- file("D:/r_file/binmtcars.dat", "rb")
bindata <- readBin(read.filename, integer(), n = 18)
 
# Print the data.
print(bindata)
 
# Read the values from 4th byte to 8th byte which represents "cyl".
cyldata = bindata[4:8]
print(cyldata)
 
# Read the values form 9th byte to 13th byte which represents "am".
amdata = bindata[9:13]
print(amdata)
 
# Read the values form 9th byte to 13th byte which represents "gear".
geardata = bindata[14:18]
print(geardata)
 
# Combine all the read values to a dat frame.
finaldata = cbind(cyldata, amdata, geardata)
colnames(finaldata) = column.names
print(finaldata)