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rregexstringr-faq

Test if characters are in a string

I'm trying to determine if a string is a subset of another string. For example:

chars <- "test"
value <- "es"

I want to return TRUE if "value" appears as part of the string "chars". In the following scenario, I would want to return false:

chars <- "test"
value <- "et"
Solution

  • Use the grepl function

    grepl( needle, haystack, fixed = TRUE)

    like so:

    grepl(value, chars, fixed = TRUE)
# TRUE

    Use ?grepl to find out more.