Extract argument of function from string with R-CodePudding

Preferably using the stringr package, I want to create a function extract() that takes for argument a vector of strings

vec <- c(
"div(span(icon(\"hospital-user\"), i18n$t(\"Enrolments\"), \"or\", i18n$t(\"Paper\"))),",
"a string with no matching pattern",
"Lala i18n$t(\"Rock\")"
)

and return all elements inside i18n$t(\""\).

In the above example, extract(vec) would return "Enrolments", "Paper", "Rock".

CodePudding user response：

We can use a regex lookaround to extract the word (\\w ) that follows a the n$t(". The $ is metacharacter, so just escape (\\) it

library(stringr)
str_extract_all(vec, '(?<=n\\$t\\(")\\w ')[[1]]
[1] "Enrolments" "Paper"      "Rock"

If there are more than one element, use unlist

unlist(str_extract_all(vec, '(?<=n\\$t\\(")\\w '))