Extract string before “|” [duplicate]

Answer 1

with stringi:

library(stringi)

df <- read.table(text="ABC|DEF|GHI,1
ABCD|EFG|HIJK,2
ABCDE|FGHI|JKL,3  
DEF|GHIJ|KLM,4
GHI|JKLM|NO|PQRS,5
BCDE|FGHI|JKL,6", sep=",", header=FALSE, stringsAsFactors=FALSE)

stri_match_first_regex(df$V1, "(.*?)\\|")[,2]
## [1] "ABC"   "ABCD"  "ABCDE" "DEF"   "GHI"   "BCDE"