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  1. x <- c("foo bar", "foo")
  2. grep("(?s)foo(?!.*bar)", x, perl=TRUE, value=TRUE)
Success #stdin #stdout 0.23s 39284KB
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Standard input is empty
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[1] "foo"
https://ideone.com/IYPbGU
language:
R (R 3.5.2)
created:
7 years ago
visibility:
public

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