I am having the following error:
a <- system("awk '{ if (/foo/) print "2","\t",$0; else print "1","\t",$0; }' file",intern=true)
However, I am getting the following error:
Error: unexpected numeric constant in "a \<- system("awk '{ if (/foo/) print "2"
I am wondering if I have to escape the internal apostrophe's but not sure how?!
There are a couple errors in the code. The code below works for me and (per your comment) returns a two column data frame:
a <- system("awk '{ if (/foo/) print 2 \"\t\" $0; else print 1 \"\t\" $0; }' file", intern = TRUE)
DF = read.table(text = a, sep = "\t")
DF
#> V1 V2
#> 1 2 foo
#> 2 1 bar
#> 3 1 asd
summary(DF)
#> V1 V2
#> Min. :1.000 Length:3
#> 1st Qu.:1.000 Class :character
#> Median :1.000 Mode :character
#> Mean :1.333
#> 3rd Qu.:1.500
#> Max. :2.000
Created on 2022-03-23 by the reprex package (v2.0.1)
I had an error with the seperator's and also wanted to keep the headers. I subsequently did the following, as I wanted to change the order.
file:
Header1 Header2
foo bar
bar bar
foo foo
I then ran the command:
a <- system("awk '{ if (/foo/) print 2 \"\t\" $0; else print 1 \"\t\" $0; }' file | awk '{print $2,$3,$1}' ", intern = TRUE)
DF = read.table(text = a, sep = " ", header=TRUE)
colnames(DF)[3] <- "Header3"
Now the output:
DF
Header1 Header2 Header3
foo bar 2
bar bar 1
foo foo 2
All works perfectly now. Thanks