obtaining first word in the string

Question

I would like to extract the first string from a vector. For example,

 y<- c('london/hilss', 'newyork/hills', 'paris/jjk')

I want to get the string before the symbol"/" i.e.,

  location 
  london
  newyork
  paris

that solution didn't work! that's why the new question, it doesn't ask about escape character. — user3570187, May 10 '17 at 18:50

score 11 · Answer 1 · answered May 10 '17 at 18:31

11

Your example is simple, for a more general case like

y<- c('london/hilss', 'newyork.hills', 'paris-jjk')

maybe following will do better?

stringr::str_extract(y, '\\w*')

answered May 10 '17 at 18:31

Sean Lin

`str_extract` returns a character vector, while `str_match` returns a character matrix. @Sean: do you have a preference? It seems to me they're basically the same, though I get annoyed with matrixes. – Nettle Aug 17 '18 at 03:03

score 2 · Answer 2 · answered May 10 '17 at 18:38

2

stringr::str_extract(a, '\\b*')

answered May 10 '17 at 18:38

score 1 · Accepted Answer · answered May 10 '17 at 18:25

1

A very simple approach with gsub

gsub("/.*", '', y)
[1] "london"  "newyork" "paris"

answered May 10 '17 at 18:25

cdeterman

Can you explain why `/.*` does not need to be escaped and, when it is, `\\/.*` produces the same result? In other words, `gsub("/.*", '', y)` is the same as `gsub("\\/.*", '', y)` – Nettle Aug 17 '18 at 02:56
@Nettle my understanding is that a forward slash does not need to be escaped. By adding `\\` you are basically escaping something that doesn't need to be escaped so nothing changes. – cdeterman Aug 17 '18 at 14:17

Rahul · Answer 4 · 2017-05-10T18:35:30.410

0

This regex will also work fine.

Regex: ^[^\/]+

It will start matching from beginning of string until a / is found.

^ outside character class [] is anchor for beginning of string.

While ^ inside character class means negated character class.

edited May 10 '17 at 18:35

answered May 10 '17 at 18:29

Rahul

4 Answers4