How to Ignore Case When Using Str_Detect

How to ignore case when using str_detect?

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))

how to make str_detect case insensitive within case_when in r

Also try regex instead of fixed:

dfm %>% 
  mutate(source = case_when( str_detect(names, regex('email|facebook|instagram', ignore_case = T))~'media',
                             str_detect(names, 'walmart|costco|target')~ 'store'))

Ignore case with multiple strings using str_detect in R

A possible solution would be to bring everything to lower case and match that with ag|field.

dat %>%
  mutate(Class_2 = case_when(
    str_detect(string = str_to_lower(Class),
               pattern = "ag|field") ~ "Agricultural",
    TRUE ~ Class
  ))

# A tibble: 3 × 2
  Class              Class_2     
  <chr>              <chr>       
1 ag                 Agricultural
2 Agricultural--misc Agricultural
3 old field          Agricultural

How to properly ignore case in regex

Consider this example :

df <- data.frame(a = c('This is not applicable', 'But this is applicable', 
                       'This is still NOT aPPLicable'))

You need to use regex in one of the stringr function like str_detect here :

library(dplyr)
library(stringr)

df %>% filter(str_detect(a, regex('not applicable', 
              ignore_case = TRUE), negate = TRUE))

#                      a
#1 But this is applicable

Or in base R use subset with grepl

subset(df, !grepl('not applicable', a, ignore.case = TRUE))

Using str_detect on data frame column values

You should first create the regex-pattern to be applied to the column, e.g.

 string_detect <- paste(c('denied', 'attach', 'bulk'), collapse = "|")

Then you need to adjust your case_when code:

folno <- fol_all %>% 
  mutate(folno_flag = case_when(
    str_detect(folno, string_detect) ~ 1, 
    TRUE ~ 0 ))

Result:

             folno folno_flag
1        123denied          1
2 attached_as_test          1
3         dept_224          0
4        bulked_up          1
5          wsd2273          0

You do not need str_detect(folno, string_detect)) == T because the statement basically says, if str_detect(folno, string_detect)) evaluates to True, then 1, 0 otherwise.

Whole code:

folno <- c('123denied', 'attached_as_test', 'dept_224', 'bulked_up', 'wsd2273')
fol_all <- data.frame(folno)

string_detect <- paste(c('denied', 'attach', 'bulk'), collapse = "|")

fol_all %>% 
  mutate(folno_flag = case_when(
    str_detect(folno, string_detect) ~ 1, 
    TRUE ~ 0 ))

stringr package using str_detect - Search for one word and exclude word

You are probably looking for a word boundary here (\\b). Wrap the desired pattern between two word boundaries to match just the word, but not parts of longer words.

library(dplyr)
library(sitrngr)

df %>% mutate(shop_YN = str_detect(remarks, '\\bshop\\b'))

# A tibble: 15 × 3
    price remarks                                                                          shop_YN
    <dbl> <chr>                                                                            <lgl>  
 1 195000 large home with a 1200 sf shop. great location close to shopping.                TRUE   
 2 213000 updated home close to shopping & schools.                                        FALSE  
 3 215000 nice location. 2br home with updating.                                           FALSE  
 4 240000 huge shop on property!                                                           TRUE   
 5 241000 close to shopping.                                                               FALSE  
 6 250000 updated, clean, great location, garage.                                          FALSE  
 7 255000 close to shopping and massive shop on property.                                  TRUE   
 8 256500 updated home near shopping, schools, restaurants.                                FALSE  
 9 260000 large home with updated interior.                                                FALSE  
10 263500 close to schools, updated, stick-built shop 1500sf.                              TRUE   
11 265000 home and shop.                                                                   TRUE   
12 277000 near schools, shopping, restaurants. partially updated home.                     FALSE  
13 280000 located close to shopping. high quality home with shop in backyard.              TRUE   
14 280000 brick 2-story. lots of shopping near by. detached garage and large shop in back… TRUE   
15 150000 fixer! needs work.                                                               FALSE

If you want Yes or No instead of the logical shop_YN, just pipe the output of str_detect into ifelse:

df %>% mutate(shop_YN = str_detect(remarks, '\\bshop\\b') %>% ifelse('Yes', 'No'))

Case-insensitive search of a list in R

Assuming that there are no variable names which differ only in case, you can search your all-lowercase variable name in tolower(names(myDataFrame)):

match("b", tolower(c("A","B","C")))
[1] 2

This will produce only exact matches, but that is probably desirable in this case.

R match ignore case and special characters

See that @Allan Cameron posted a very similar solution right before me... going to leave this anyways because different enough.. ?!

list1 <- c('a', 'b', 'c')
list2 <- c('A', 'B', 'C')
list3 <- c('a-', 'B_', '- c')

regex to replace any symbol that is not an alphabetic character with an empty string:

f <- function(x) {
  return(tolower(gsub("[^[:alpha:]]", "", x)))
}

match(f(list1), f(list2))
match(f(list1), f(list3))
match(f(list2), f(list3))

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