CODEWITHSUNDEEP
rperlcsvbigdata
Qbik
Qbik

Reputation: 6157

Low level access to files (txt,csv) under R (reading in only chosen lines, without reading whole file into memory)

Is there any simple R function to read specific lines from text files (*.txt or especially *.csv) without reading the whole file into memory? I would like to read in only chosen lines of the file, for example reading only lines with x1==b:

x1 x2 x3
a  1  1
a  2  2
b  2  3
b  1  4
a  2  1
->   
x1 x2 x3
b  2  3
b  1  4

maybe some Perl tool for R, but is it easy (for R user)?

Upvotes: 1

Views: 218

Answers (1)

Dirk is no longer here
Dirk is no longer here

Reputation: 368619

The default read.* functions all read everything by default. So one option is to use an external filter --- as e.g. an awk or sed script, or a grep expression --- and then to read via read.table() from that stream after having filtered.

Upvotes: 2

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