在单张xlsx文件中附加r输出

Question

How can i append my R outputs in a single sheet of xlsx file? I am currently working on web crawling wherein i need to scrap the user reviews from website and save it in my deskstop in xlsx format. I need to every time change the website url(as user reviews are in different pages) in my code and save the output in one sheet of xlsx file.

Can you please help me with the code of appending outputs in a single sheet of xlsx file? Below is the code which i am using: Every time i need to change the website url and run the same below code and save the corresponding output in a single sheet of mydata.xlsx

library("rvest")
htmlpage <- html("http://www.glassdoor.com/GD/Reviews/Symphony-Teleca-Reviews-E28614_P2.htm?sort.sortType=RD&sort.ascending=false&filter.employmentStatus=REGULAR&filter.employmentStatus=PART_TIME&filter.employmentStatus=UNKNOWN")
proshtml <- html_nodes(htmlpage, ".pros")
pros <- html_text(proshtml)
pros

data=data.frame(pros)

library(xlsx)
write.xlsx(data, "D:/mydata.xlsx", append=TRUE)

Answer 1

A trivial, but super-slow way:

If you only need to add (a few) row(s) to an existing Excel file, and it only has one sheet to which you want to append, you can just do a simple read => overwrite step:

SHEET.NAME <- '...' # fill in with yours
existing.data <- read.xlsx(file, sheetName = SHEET.NAME)
new.data <- rbind(existing.data, data)
write.xlsx(new.data, file, sheetName = SHEET.NAME, row.names = F, append = F)

Note:

• It's quite slow in general, will work only for small scale
• read.xlsx is a slow function. Try read.xlsx2 to make it much faster (see the difference in the docs)
• If your R process is run once and keeps working for a long time, obviously don't do it this way (reading and overwriting a file is ridiculous in that case)

Answer 2

look at package xlsx .

?write.xlsx will show you what you want. append=TRUE is the key.

========= EDIT TO CORRECT =========

As @Jakub pointed out, append=TRUE adds another worksheet to the file.

========= EDIT TO ADD: ANOTHER METHOD ==========

Another method is to save the data to a .csv file, which could easily open from excel. In this case, the append=T works as expected (adding to the existing sheet):

write.table(df,"D:/MyFile.csv",append=T,sep=",")