re2_match. re2r 0.1.0

Usage

re2_match(string, pattern, anchor = UNANCHORED, parallel = FALSE, grain_size = 1e+05, ...)
re2_match_all(string, pattern, anchor = UNANCHORED, parallel = FALSE, grain_size = 1e+05, ...)

Arguments

string: a character vector
pattern: a character vector or pre-compiled regular expressions
anchor: see UNANCHORED
parallel: use multithread
grain_size: a minimum chunk size for tuning the behavior of parallel algorithms
...: further arguments passed to re2

Value

For re2_match, a character matrix. First column is the complete match, followed by one column for each capture group with names.

For re2_match_all, a list of character matrices.

Description

Find matched groups from strings.

Examples


strings <- c("Gym: 627-112-1433", "Apple x2",
             "888 888 8888", "This is a test.",
             "627-112-1433 223-343-2232")
phone <- "([2-9][0-9]{2})[- .](?P<second>[0-9]{3})[- .]([0-9]{4})"
re2_extract(strings, phone)

[1] "627-112-1433" NA             "888 888 8888" NA             "627-112-1433"

re2_match(strings, phone)

     .match         .1    second .3    
[1,] "627-112-1433" "627" "112"  "1433"
[2,] NA             NA    NA     NA    
[3,] "888 888 8888" "888" "888"  "8888"
[4,] NA             NA    NA     NA    
[5,] "627-112-1433" "627" "112"  "1433"


re2_extract_all(strings, phone)

[[1]]
[1] "627-112-1433"

[[2]]
character(0)

[[3]]
[1] "888 888 8888"

[[4]]
character(0)

[[5]]
[1] "627-112-1433" "223-343-2232"


re2_match_all(strings, phone)

[[1]]
     .match         .1    second .3    
[1,] "627-112-1433" "627" "112"  "1433"

[[2]]
     .match .1 second .3

[[3]]
     .match         .1    second .3    
[1,] "888 888 8888" "888" "888"  "8888"

[[4]]
     .match .1 second .3

[[5]]
     .match         .1    second .3    
[1,] "627-112-1433" "627" "112"  "1433"
[2,] "223-343-2232" "223" "343"  "2232"



regexp = re2("test",case_sensitive = FALSE)
re2_match("TEST", regexp)

     .match
[1,] "TEST"


# differences from stringi

# This kind of repeating capturing group works differently.
re2_match("aasd", "(a*)+")

     .match .1  
[1,] "aa"   "aa"

stringi::stri_match("aasd", regex = "(a*)+")

     [,1] [,2]
[1,] "aa" ""  


# In stringi, "" empty search patterns return NA.
# In re2r, empty search patterns will match
# empty string.

re2_match("abc", "")

     .match
[1,] ""    

stringi::stri_match("abc", regex = "")

Warning message:
empty search patterns are not supported
     [,1]
[1,] NA