A regular expression ("regex") is a specific sequence of characters that broadly or narrowly match patterns in your data. You can use regular expressions to create more flexible filters in charts and controls. You can also use the following regular expression functions in calculated field formulas:
| REGEXP_EXTRACT | Returns the first matching substring in the input value which matches the regular expression pattern. Learn more. |
| REGEXP_MATCH | Returns true if the input value matches the regular expression pattern, otherwise returns false. Learn more. |
| REGEXP_REPLACE | Replaces all occurrences of text which matches the regular expression pattern in the input value with the replacement string. Learn more. |
Examples
These regular expressions illustrate how to use the functions above.
Extracts the top-level directory in a URL:
REGEXP_EXTRACT(URL, '^https://[^/]+/([^/]+)/')For example, if the URL field contained this page's address, the function above would return datastudio.
Categorize ad campaigns by language:
For example, applying this to the Campaign dimension in the Google Analytics Demo account gives these results:
| Campaign | Language |
|---|---|
| Campaign #1 | Other language |
| 1000549 | Google Analytics Demo | DR | apontes | NA | US | en | Hybrid | AW SEM | BKWS | ~ AW - Google Brand (US) | English |
| 1000549 | Google Analytics Demo | DR | apontes | NA | CA | es | Hybrid | AW SEM | BKWS | ~ AW - YouTube (CA) | Spanish |
Swap the order of sections in a string:
In the example above, the sections are separated by a colon (:).
Regex metacharacters
Metacharacters are characters that have special meaning in a regular expression. Following are some of the more common metacharacters you can use. Note that the examples open in the Google Analytics Help Center, but the information presented there applies equally to Data Studio.
See google/RE2 Github documentation for complete regular expression syntax.
Wildcards
| . | Matches any single character (letter, number or symbol) | 1. matches 10, 1A 1.1 matches 111, 1A1 Examples |
| ? | Matches the preceding character 0 or 1 times | 10? matches 1, 10 Examples |
| + | Matches the preceding character 1 or more times | 10+ matches 10, 100 Examples |
| * | Matches the preceding character 0 or more times | 1* matches 1, 10 Examples |
| | | Creates an OR match Do not use at the end of an expression |
1|10 matches 1, 10 Examples |
Anchors
| ^ | Matches the adjacent characters at the beginning of a string | ^10 matches 10, 100, 10x ^10 does not match 110, 110x Examples |
| $ | Matches the adjacent characters at the end of a string | 10$ matches 110, 1010 10$ does not match 100, 10x Examples |
Groups
| ( ) | 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 Examples |
| [ ] | Matches the enclosed characters in any order anywhere in a string | [10] matches 012, 120, 210 Examples |
| - | Creates a range of characters within brackets to match anywhere in a string | [0-9] matches any number 0 through 9 Examples |
Escape
| \ |
Indicates that the adjacent character should be interpreted literally rather than as a regex metacharacter. See the note below on matching metacharacters. |
\. indicates that the adjacent dot should be interpreted as a period or decimal rather than as a wildcard. 216\.239\.32\.34 matches 216.239.32.34 Examples |
Character classes
|
\d |
digits (≡ [0-9]) |
|
\D |
not digits (≡ [^0-9]) |
|
\s |
whitespace (≡ [\t\n\f\r ]) |
|
\S |
not whitespace (≡ [^\t\n\f\r ]) |
|
\w |
word characters (≡ [0-9A-Za-z_]) |
|
\W |
not word characters (≡ [^0-9A-Za-z_]) |
Tips
Use simple expressions
Keep your regular expressions simple. Simple regex is easier for another user to interpret and modify.
Case sensitivity
(?i) flag. For example:REGEXP_EXTRACT(MyField, '(?i)(a.*)')extracts both "abc123" and "ABC123".
Escape the backslash
As noted above, you use the backslash (\) to escape regex metacharacters when you need those characters to be interpreted literally. To match a backslash in a quoted string, you'll need to escape that as well, resulting in 2 backslashes in your regex. For example:
REGEXP_REPLACE(String, "(\\[.*\\])\\+(\\[.*\\])","\\2 \\1")
As an alternative, consider using the Raw string literal prefix, R:
REGEXP_REPLACE(String, R"(\[.*\])\+(\[.*\])",R"\2 \1")