[UA] About regular expressions (regex)

Analytics supports regular expressions so you can create more flexible definitions for things like view filters, goals, segments, audiences, content groups, and channel groupings.

This article covers regular expressions in both Universal Analytics and Google Analytics 4. 

In the context of Analytics, regular expressions are specific sequences of characters that broadly or narrowly match patterns in your Analytics data.

For example, if you wanted to create a view filter to exclude site data generated by your own employees, you could use a regular expression to exclude any data from the entire range of IP addresses that serve your employees. Let’s say those IP addresses range from - Rather than enter 25 different IP addresses, you could create a regular expression like 198\.51\.100\.\d* that matches the entire range of addresses.

Or if you wanted to create a view filter that included only campaign data from two different cities, you could create a regular expression like San Francisco|New York (San Francisco or New York).

Regex metacharacters


. Matches any single character (letter, number or symbol) 1. matches
10, 1A

1.1 matches
111, 1A1

? Matches the preceding character 0 or 1 times 10? matches
1, 10

+ Matches the preceding character 1 or more times 10+ matches
10, 100

* Matches the preceding character 0 or more times 1* matches
1, 10

| Creates an OR match

Do not use at the end of an expression
1|10 matches
1, 10



^ Matches the adjacent characters at the beginning of a string ^10 matches
10, 100, 10x

^10 does not match
110, 110x

$ Matches the adjacent characters at the end of a string 10$ matches
110, 1010

10$ does not match
100, 10x



( ) Matches the enclosed characters in exact order anywhere in a string

Also used to group other expressions
(10) matches
10, 101, 1011

([0-9]|[a-z]) matches
any number or lower-case letter

[ ] Matches the enclosed characters in any order anywhere in a string [10] matches
012, 120, 210

- Creates a range of characters within brackets to match anywhere in a string [0-9] matches any number 0 through 9



\ Indicates that the adjacent character should be interpreted literally rather than as a regex metacharacter \. indicates that the adjacent dot should be interpreted as a period or decimal rather than as a wildcard.

216\.239\.32\.34 matches




Default behavior between Universal Analytics and Google Analytics 4

By default, regular expressions in Universal Analytics properties are treated as a "partial match." The expression will be true if the pattern you provide is contained anywhere in the data.

For example, if you provide the pattern "India" the regex matches "India",  "Indian", "Indiana", "Indianapolis", and so on. You don't need to use metacharacters to achieve this partial match. 

In a Google Analytics 4 property, the default regex is a "full match." The data must exactly match the pattern you provide. For example, the pattern "India" only matches "India." To make this regex act like a partial match, you must use metacharacters: "India.*" will return any value that begins with "India" and ends with anything (or nothing) else.

Use simple expressions

Keep your regular expressions simple. Simple regex is easier for another user to interpret and modify.

Match metacharacters

Use the backslash (\) to escape regex metacharacters when you need those characters to be interpreted literally. For example, if you use a dot as the decimal separator in an IP address, escape it with a backslash (\.) so that it isn’t interpreted as a wildcard.

Use metacharacters to limit the match

Regular expressions are greedy by nature: if you don’t tell them not to, they match what you specify plus any adjacent characters. For example, in a partial match, site matches mysite, yoursite, theirsite, parasite--any string that contains “site”. If you need to make a specific match, construct you regex accordingly. For example, if you need to match only the string “site”, then construct your regex so that “site” is the both the beginning and end of the string: ^site$.

Google RE2 regex syntax

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