How to extract string between to patterns with special characters in R

Question

From string a I would like to extract everything between |Request| and the next occurance of |:

 a <- "|Request|\nSample inlet port of the HIP cartridge with |overflow| formed "
    
 gsub(".*\\|Request\\| (.+) |.*", "\\1", a)

Applying gsub this way did not yield the expected result. How could I do it instead?

You can get the values using a capturing group `\|Request\|([^|]+)` https://regex101.com/r/zmUIM0/1/ — The fourth bird, Aug 17 '20 at 07:58

score 1 · Accepted Answer · answered Aug 17 '20 at 07:58

1

You need to use lazy dot, and also your input pattern should match the entire input, given that you are replacing with capture group:

a <- "|Request|\nSample inlet port of the HIP cartridge with |overflow| formed "
sub("^.*\\|Request\\|\\s*(.+?)\\s*\\|.*$", "\\1", a)

[1] "Sample inlet port of the HIP cartridge with"

answered Aug 17 '20 at 07:58

Tim Biegeleisen

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If the |-symbol does not occurr afterwards anymore I would like to get the substring from the first match until the end. How could I do this? – volfi Aug 17 '20 at 09:25
I don't have enough sample inputs to come up with a good enough alternative regex even worthy of a comment here. – Tim Biegeleisen Aug 17 '20 at 10:01

score 1 · Answer 2 · answered Aug 17 '20 at 07:58

1

You can use sub to capture everything after |Request| until the next | occurs.

sub(".*\\|Request\\|(.*?)\\|.*", "\\1", a)
#[1] "\nSample inlet port of the HIP cartridge with "

answered Aug 17 '20 at 07:58

Ronak Shah

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How to extract string between to patterns with special characters in R

2 Answers2