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I have a csv file with extra white spaces that I want to read into R as a dataframe, stripping the white spaces.

This can be achieved by using 

testdata<-read.csv("file.csv", strip.white=TRUE)

The problem is that the dataset large and takes about half an hour. The fread function is at least twice as fast but does not have the strip.white function.

library("data.table")
testdata<-data.frame(fread("file.csv"))

Is there a quick way to strip the white spaces from the columns after reading in, or is there some way to strip the white spaces using fread?

If it was just a one time import, I wouldn't mind that much, but I need to do this several times and regularly.

DaReal
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  • There is a parameter `strip.white` which is set by default to `TRUE` in fread right now and you can also pass `data.table = FALSE` to fread to receive a `data.frame` after reading the dataset – Marcin Dec 30 '15 at 12:22

2 Answers2

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You can use str_trim from stringr package:

library(stringr)
testdata[,sapply(.SD,str_trim)]

By default it trims whitesapces in both sides, but you can set the side:

testdata[,sapply(.SD,str_trim,side="left")]
agstudy
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  • Thank you, this would have done the trick. However, my colleague has a solution outside of R. He used a PERL command on his local Mac OSX machine to strip padding: perl -lape 's/\s+//sg' /path/to/file.csv > /path/to/fileV2.csv This reduces the file size and strips whitespaces before reading it into R. – DaReal Mar 31 '14 at 10:06
  • Just a word of caution: using @agstudy's solution will convert numeric columns to chr if these also contain spaces. Otherwise, nice solution. – fridaymeetssunday Apr 23 '15 at 07:55
4

There is a parameter strip.white which is set by default to TRUE in fread right now and you can also pass data.table = FALSE to fread to receive a data.frame after reading the dataset

Marcin
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    Thanks, the fread function has been upgraded since I first ran into this issue, so this is now the way to go. – DaReal Jan 31 '16 at 15:00