CODEWITHSUNDEEP
regexr
user6489260
user6489260

Reputation:

Remove part of string before last "/"

I want to remove everything before /query .. for e.g

I have no idea about regular expressions so doing this is difficult for me

Note : the reference should be /query as the link mentioned below may have some different patterns like - www.abcd.wsd/asd/asdcd/asrr/query=xyz

www.html.com/query=abcd

should result into 

 query = abcd

Upvotes: 2

Views: 727

Answers (4)

jbaums
jbaums

Reputation: 27398

Another option is:

sub('.*/query', '/query', 'www.html.com/query=abcd')

i.e., replace "all characters up to and including [the last instance of] /query" with "/query".

Upvotes: 1

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 627110

A generic regex solution to extract the query appearing after the last / and that is followed with characters other than / is

s <- c("www.abcd.wsd/asd/asdcd/asrr/query=xyz","www.html.com/query=abcd","www.cmpnt.com/query=fgh/noquery=dd")
sub("^.*/(query[^/]*).*$", "\\1", s)
## => "query=xyz"  "query=abcd" "query=fgh"

See this R demo

The regex is

^.*/(query[^/]*).*$

See the regex demo

Details:

  • ^ - start of string
  • .* - match any 0+ characters as many as possible up to the last
  • / - a literal forward slash char
  • (query[^/]*) - capture group 1 matching a query substring followed with 0+ characters other than / (see [^/]* negated character class with a * quantifier)
  • .* - zero or more any characters up to
  • $ - the end of string.

Upvotes: 2

Shenglin Chen
Shenglin Chen

Reputation: 4554

string<-c('www.abcd.wsd/asd/asdcd/asrr/query=xyz','www.html.com/query=abcd')
gsub('.*\\/([^/]+)$','\\1',string)
#[1] "query=xyz"  "query=abcd"

Upvotes: 0

zx8754
zx8754

Reputation: 56219

We can abuse basename function which was intended to get filename, dropping all folders:

basename("www.abcd.wsd/asd/asdcd/asrr/query=xyz")
# [1] "query=xyz"

basename("www.html.com/query=abcd")
# [1] "query=abcd"

Note that this will fail when query is not at the end:

basename("www.html.com/query=abcd/xyz")
# [1] "xyz"

Upvotes: 2

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