Write different data frame in one .csv file with R

问题:

I have 3 data frame, and I want them to be written in one single .csv file, one above the others, not in a same table. So, 3 different tables in one csv file. They all have same size.

The problem with write.csv: it does not contain "append" feature

The problem with write.table: csv files from write.table are not read prettily by Excel 2010 like those from write.csv

Post I already read and in which I could not find solution to my problem :

• write.csv() a list of unequally sized data.frames
• Creating a file with more than one data frame

Solution ?

回答1:

write.csv just calls write.table under the hood, with appropriate arguments. So you can achieve what you want with 3 calls to write.table.

write.table(df1, "filename.csv", col.names=TRUE, sep=",")
write.table(df2, "filename.csv", col.names=FALSE, sep=",", append=TRUE)
write.table(df3, "filename.csv", col.names=FALSE, sep=",", append=TRUE)

Actually, you could avoid the whole issue by combining your data frames into a single df with rbind, then calling write.csv once.

write.csv(rbind(df1, d32, df3), "filename.csv")

回答2:

We use sink files:

# Sample dataframes:
df1 = iris[1:5, ]
df2 = iris[20:30, ]

# Start a sink file with a CSV extension
sink('multiple_df_export.csv')

 # Write the first dataframe, with a title and final line separator 
cat('This is the first dataframe')
write.csv(df1)
cat('____________________________')

cat('\n')
cat('\n')

# Write the 2nd dataframe to the same sink
cat('This is the second dataframe')
write.csv(df2)
cat('____________________________')

# Close the sink
sink()