Multiple strings with str_detect R

Magick.M picture Magick.M · Mar 12, 2016 · Viewed 40.7k times · Source

I want to find multiple strings and put it in a variable, however I keep getting errors.

queries <- httpdf %>% filter(str_detect(payload, "create" || "drop" || "select"))
Error: invalid 'x' type in 'x || y'

queries <- httpdf %>% filter(str_detect(payload, "create" | "drop" | "select"))
Error: operations are possible only for numeric, logical or complex types

queries1 <- httpdf %>% filter(str_detect(payload, "create", "drop", "select"))
Error: unused arguments ("drop", "select")

None of these worked. Is there another way to do it with str_detect or should i try something else? I want them to show up as in the same column as well.

Answer

fabilous picture fabilous · May 3, 2018

An even simpler way, in my opinion, for your quite short list of strings you want to find can be:

queries <- httpdf %>% filter(str_detect(payload, "create|drop|select"))

As this is actually what

[...] paste(c("create", "drop", "select"),collapse = '|')) [...]

does, as recommended by @penguin before.

For a longer list of strings you want to detect I would first store the single strings into a vector and then use @penguin's approach, e.g.:

strings <- c("string1", "string2", "string3", "string4", "string5", "string6")
queries <- httpdf %>% 
  filter(str_detect(payload, paste(strings, collapse = "|")))

This has the advantage that you can easily use the vector strings later on as well if you want to or have to.