R正则表达式在数据帧列中第二次出现/后删除所有内容

Question

I have data stored in a dataframe column that looks like this:

/travel
/food and drink/restaurants
/food and drink
/sports/outdoors/climbing

/news
/family

Each row has some number of "/" but they always start with a "/". Some lines are also blank. I just need to convert this data to only include the text after the first "/" but before the second "/". I also want to capitalize the first letter of each word of the result. So I'd hope the result to look like this:

Travel
Food And Drink
Food And Drink
Sports

News
Family

Answer 1

x <- c('/travel',
       '/food and drink/restaurants',
       '/food and drink',
       '/sports/outdoors/climbing',
       '/news',
       '/family')

Upcase every word

gsub('(?<=\\b)([a-z])', '\\U\\1', x, perl =  TRUE)

# [1] "/Travel"                     "/Food And Drink/Restaurants" "/Food And Drink"            
# [4] "/Sports/Outdoors/Climbing"   "/News"                       "/Family"   

Extract the first /.. group

gsub('^/([^/]+)|.', '\\1', x)

# [1] "travel"         "food and drink" "food and drink" "sports"         "news"          
# [6] "family" 

Combine the two

gsub('(?<=\\b)([a-z])', '\\U\\1', gsub('^/([^/]+)|.', '\\1', x), perl =  TRUE)

# [1] "Travel"         "Food And Drink" "Food And Drink" "Sports"         "News"          
# [6] "Family"  

If you don't care about the "and" being uppercase, you can use the second gsub and tools::toTitleCase

tools::toTitleCase(gsub('^/([^/]+)|.', '\\1', x))

# [1] "Travel"         "Food and Drink" "Food and Drink" "Sports"         "News"          
# [6] "Family" 

Answer 2

require(magrittr)

txt <- c("/travel", "/food and drink/restaurants", "/food and drink", "/sports/outdoors/climbing", "", "/news", "/family")

strsplit(txt, "/") %>% sapply( '[', 2 )  #per Frank's suggestion

##  [1] "travel"         "food and drink" "food and drink" "sports"        
##  [5] NA               "news"           "family"        

Answer 3

A quick way would be the following: I'm assuming that there only words characters \\w and white spaces \\s in the part you want to collect.

char<- c("/travel","/food and drink/restaurants","/food and drink","/sports/outdoors/climbing","","/news","/family")

match <- regexpr("[\\w\\s]+",char,perl=TRUE)
regmatches(char,match)

## regmatches(char,match)
## [1] "travel"         "food and drink" "food and drink" "sports"        
## [5] "news"           "family"   

Answer 4

You would need to install the stringi package (and you should probably have it anyway :) but the following should do the trick

stringi::stri_trans_totitle( gsub("/([^/]+)", "\\1", data))

The gsub simply picks out the text after the first / up until either the second / or the end of the string. stringi::stri_trans_totitle then does the case conversion for you.

> s <-c("/food and drink/restaurants", "/beer and wine", "", "/news")
> stringi::stri_trans_totitle( gsub("/([^/]+)", "\\1", s))
[1] "Food And Drinkrestaurants" "Beer And Wine"            
[3] ""                          "News"