How to ignore case when using str_detect?

Question

stringr package provides good string functions.

To search for a string (ignoring case)

one could use

stringr::str_detect('TOYOTA subaru',ignore.case('toyota'))

This works but gives warning

Please use (fixed|coll|regex)(x, ignore_case = TRUE) instead of ignore.case(x)

What is the right way of rewriting it?

consider a user that prefers to avoid regex magic – userJT Jun 13 '17 at 19:32 — userJT, Jun 13 '17 at 19:32

score 62 · Answer 1 · edited Aug 01 '21 at 14:37

62

You can use regex (or fixed as suggested in @lmo's comment depending on what you need) function to make the pattern as detailed in ?modifiers or ?str_detect (see the instruction for pattern parameter):

library(stringr)
str_detect('TOYOTA subaru', regex('toyota', ignore_case = T))
# [1] TRUE

edited Aug 01 '21 at 14:37

giocomai

3,043
21
24

answered Jun 13 '17 at 19:36

Psidom

209,562
33
339
356

4

or using `fixed`: `str_detect('TOYOTA subaru', fixed('toyota', ignore_case=TRUE))`. – lmo Jun 13 '17 at 19:38
I love that the question is simple and clear and the answer is simple and clear. A rare treat! – stevec Feb 15 '21 at 00:26
1

Currently, I get the FALSE output with stringr at ‘1.4.0’. – Jiaxiang Aug 02 '21 at 15:05

score 36 · Answer 2 · answered Apr 11 '20 at 20:50

36

You can save a little typing with (?i):

c("Toyota", "my TOYOTA", "your Subaru") %>% 
  str_detect( "(?i)toyota" )
# [1]  TRUE  TRUE FALSE

answered Apr 11 '20 at 20:50

David T

1,993
10
18

8

This is the best answer in for both single and multiple search terms. For example, ```str_detect(X, (?i)cws|usgs|fws)``` – Jessica Burnett Jun 17 '21 at 17:58
I frequently use this with `str_subset()`. It has saved me a lot of typing. – San Jun 20 '21 at 05:07
(?i) may also be used with `data.table` `%like%` operator for case-insensitive search. Or you may just use `%ilike%` operator which has been made specifically for case-insensitive search. – San Jun 20 '21 at 05:41
Is '(?i)' a way in the original regular expressions? – Jiaxiang Aug 02 '21 at 15:09

score 30 · Accepted Answer · answered Jun 15 '17 at 23:02

30

the search string must be inside function fixed and that function has valid parameter ignore_case

str_detect('TOYOTA subaru', fixed('toyota', ignore_case=TRUE))

answered Jun 15 '17 at 23:02

userJT

11,486
20
77
88

Curiously, why I get the FALSE output from 'regex', what is the difference between the two? – Jiaxiang Aug 02 '21 at 15:07

score 8 · Answer 4 · answered Oct 16 '19 at 20:45

You can use the base R function grepl() to accomplish the same thing without a nested function. It simply accepts ignore.case as an argument.

grepl("toyota", 'TOYOTA subaru', ignore.case = TRUE)

(Note that the order of the first two arguments (pattern and string) are switched between grepl and str_detect).

score 1 · Answer 5 · answered May 24 '22 at 18:24

1

Or you can erase all capitalization while you search:

str_detect(tolower('TOYOTA subaru'), 'toyota')

answered May 24 '22 at 18:24

Unrelated

347
2
14

How to ignore case when using str_detect?

5 Answers5

Linked

Related