Minimally reproducible example:
fread('1,2,"3,a"\n4,5,"6,b"', verbose=T)
produces parsing log
Detecting sep ...
sep==','(ascii 44) with 2 lines of 3 fields using quote rule 0
sep==','(ascii 44) with 2 lines of 4 fields using quote rule 3
Detected 4 columns on line 1. This line is either column names or first data row (first 30 chars): <<1,2,"3,a">>
and the output dataset:
V1 V2 V3 V4
1: 1 2 "3 a"
2: 4 5 "6 b"
Minimally reproducible example:
produces parsing log
and the output dataset: