r - Read quoted values in txt file with data.table::fread() -


i have simple txt file: (values in quotes , separated tabs)

"col1" "col2" "col3"   "a" "1,1" "c"   "b" "2,1" "c"   "c" "3,1" "c"

i read file using fread(). since middle column should numeric, use dec = ",".

however, command:

fread("myfile.txt", sep = "\t", dec = ",", header = true, stringsasfactors = false)

fails read col2 numeric. specifying colclasses = c("character", "numeric", "character") not make difference.

is there way accurately read file using fread() (without post-processing)?

any appreciated

i'm going backtrack little bit on previous comments; looks read.table handle situation successfully.

demonstrating following object, 

df <- data.frame(     col1 = letters[1:3],      col2 = sub(".", ",", 1:3 + 0.1, fixed = true),      col3 = rep("c", 3),      stringsasfactors = false )

which looks on disk: 

write.table(     df,     sep = "\t",      row.names = false ) # "col1"    "col2"  "col3" # "a"   "1,1"   "c" # "b"   "2,1"   "c" # "c"   "3,1"   "c"

writing temporary file, 

tf <- tempfile() write.table(     df,     file = tf,     sep = "\t",      row.names = false )

read.table process second column numeric when proper arguments provided: 

str(read.table(tf, header = true, sep = "\t", dec = ",")) # 'data.frame': 3 obs. of  3 variables: #  $ col1: chr  "a" "b" "c" #  $ col2: num  1.1 2.1 3.1 #  $ col3: chr  "c" "c" "c"

more conveniently, read.delim2 may used also: 

str(read.delim2(tf, header = true)) # 'data.frame': 3 obs. of  3 variables: #  $ col1: chr  "a" "b" "c" #  $ col2: num  1.1 2.1 3.1 #  $ col3: chr  "c" "c" "c"

i can't why fread not handle this, if sufficiently common scenario package maintainers may want account it. might consider opening issue ticket on github repository , inquiring this.


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