Question

I would like to be able to scan a csv file row by row in R and exclude the rows that contain the word “target”.

The problem is that the data comes from different places and the word “target” can come up in a number of different columns in the data frame.

So I need a line in a function that will look for this string, and if it is not present, then append that row to a new data frame (that I will then write out as a new csv).

Any and all help gratefully recieved.

Answer 1

Andrie’s comment is probably the way most users would approach this, but if you want to do this at the reading in stage, you can try this:

1. Read in your csv using readLines and make any lines that have the text target blank:

   temp = gsub(".*target.*", "", readLines("test.csv"))
   

2. Use read.table to convert temp to a data.frame. Since all lines that have the text target are now blank, the default blank.lines.skip=TRUE in read.table should correctly read in the rest of your data as a data.frame.

   read.table(text=temp, sep=",", header=TRUE)