数据框r和grepl中的两个条件

Question

I have got the following data frame

x <- c("Action", "Adventure", "Animation")
my_text <- c("During check has Animation.", "check none.", "Here is Adventure.")
a <- c(1,2,3)
result <- c(1,5.2,3)

    x           my_text                     a   result
1   Action      During check has Animation. 1   1
2   Adventure   check none.                 2   5.2
3   Animation   Here is Adventure.          3   3

Basically I am trying to use grepl to give me the results column. I am ok to use one condition in grepl and check for word "check" and if found produce 5.2. However what I want to is to find "check" but if "during check" found value from a should be used. So, if "check" then 5.2 but when "during check" value from column a, for anything else value from a as well?

Answer 1

You can try using lookbehind. With your data:

df = data.frame(x=x,my_text=my_text,a=a,stringsAsFactors = FALSE)

df$result = ifelse(grepl("(?<!during )\\bcheck",df$my_text,perl=TRUE,ignore.case = TRUE),
                   5.2,df$a)
> df
          x                     my_text a result
1    Action During check has Animation. 1    1.0
2 Adventure                 check none. 2    5.2
3 Animation          Here is Adventure. 3    3.0