Regex UTM google

Question

I'm trying to extract a UTM from a Google link using r, but my regex doesn't seem to work properly.

Here an example of a google link :

xxx/yyy?utm_medium=display&utm_source=ogury&utm_campaign=TOTO&zzz=coco

I tried the following regex to extract TOTO:

.+&utm_campaign=([[a-z]]+)&.+

with no success.

If someone can help, thanks!

score 2 · Answer 1 · answered Jun 27 '18 at 20:38

In your pattern, [[a-z]]+ is a malformed bracket expression, because it matches any char from the [[a-z] bracket expression (any lowercase ASCII letter or [) and then matches one or more ] chars. You meant to use single [ and ] here.

You may use sub with the following regex:

sub(".*[&?]utm_campaign=([^&]+).*", "\\1", s)

See the regex demo.

Details

.* - any 0+ chars, as many as possible
[&?] - a ? or &
utm_campaign= - a literal substring
([^&]+) - Capturing group 1: one or more chars other than & chars
.* - any 0+ chars, as many as possible

The \1 is the replacement backreference that puts the contents of Group 1 into the result.

See the R demo:

s <- "xxx/yyy?utm_medium=display&utm_source=ogury&utm_campaign=TOTO&zzz=coco"
sub(".*[&?]utm_campaign=([^&]+).*", "\\1", s)
## => [1] "TOTO"

score 0 · Answer 2 · answered Jun 27 '18 at 20:37

0

You could use:

(?:&utm_campaign=)(\w+)

and use the first group captured

Try it Online

answered Jun 27 '18 at 20:37

Matheus Cuba

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Note that in case `utm_campaign` is the first query string param, it will have `?` in front, so `(?:&utm_campaign=)(\w+)` might not work in all cases. Besides, note that `(?:&utm_campaign=)` = `&utm_campaign=`. – Wiktor Stribiżew Jun 27 '18 at 20:46

Jacob Boertjes · Answer 3 · 2018-06-27T20:55:40.003

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You are searching for [[a-z]]+ however TOTO is uppercase, so not between 'a' and 'z'. You can update it to [[A-Za-z]]+ to match any case letter.

EDIT: [[A-Za-z]]+ will match any case letter, but will also match any '[' or ']' characters. If you do not wish to match these then you can change it to [A-Za-z]+ to only match any case letters

edited Jun 27 '18 at 20:55

answered Jun 27 '18 at 20:38

Jacob Boertjes

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The `[[A-Za-z]]+` matches any char from the `[[A-Za-z]` bracket expression (any ASCII letter or `[`) and then matches one or more `]` chars (e.g. `[]]]]]]]]]]]]]]]]]]` like strings). – Wiktor Stribiżew Jun 27 '18 at 20:43
Yes, however this is how it was originally written so I assumed it was intended as such. – Jacob Boertjes Jun 27 '18 at 20:52
Thanks for pointing out this error, I have edited my answer to address this. – Jacob Boertjes Jun 27 '18 at 20:56

score 0 · Answer 4 · answered Jun 27 '18 at 20:49

Here's a regex string that'll match the value of a utm_campaign parameter, regardless of its position in the query string.

(?<TOTO>(?<=utm_campaign=).*?(?=&|$))

Explanation:

?<TOTO> captures the result into a TOTO key after the regex is executed
(?<=utm_campaign=) is a look-behind that will ensure that the value is preceded by utm_campaign=
- .*? will find the parameter value (i.e. TOTO). The reason for the ? is lazy evaluation - it will only search until the next rule is matched (see point below)
- (?=&|$) is a look-ahead that will match either an & or the end of the string (in the case that utm_campaign is the last parameter)

Regex UTM google

4 Answers4