How can I check if multiple strings exist in another string?

Question

I have this string:

myStr <- "I am very beautiful btw"
str <- c("very","beauti","bt")

Now I want to check whether myStr includes all strings in str, how can I do this in R? For example above it should be TRUE. Many Thanks

Answer 1

Yes, you can use grepl (not grep, actually), but you must run it once for each substring:

> sapply(str, grepl, myStr)
  very beauti     bt 
  TRUE   TRUE   TRUE 

To get only one result if all of them are true, use all:

> all(sapply(str, grepl, myStr))
[1] TRUE

Edit:

In case you have more than one string to check, say:

myStrings <- c("I am very beautiful btw", "I am not beautiful btw")

You then run the sapply code, which will return a matrix with one row for each string in myStrings. Apply all on each row:

> apply(sapply(str, grepl, myStrings), 1, all)
[1]  TRUE FALSE

Answer 2

Using stringr you could do:

str_detect(myStr, str)

Which returns a result for each substring:

#[1] TRUE TRUE TRUE

Or as per @thelatemail suggestion, if you want to know if all of them are true:

all(str_detect(myStr,str))

Which gives:

#[1] TRUE

You could also find the location (start, end) of every character in myStr that matches str

str_locate(myStr, str)

Which gives:

#     start end
#[1,]     6   9
#[2,]    11  16
#[3,]    21  22