# Regular expressions

`snipexp:` is the one operator that does not change which sites are found - it changes what is shown for each of them. That is how a list of sites becomes a list of publisher ids, phone numbers or plugin names.

Instead of the text surrounding the match, the snippet becomes whatever your expression captures.

The expression is a PCRE pattern with its delimiters - usually `|`, since a query rarely contains one - and **at least one capturing group**, because what the group captures is what you get. Flags follow the closing delimiter, so `i` makes it case-insensitive. Without a capturing group the snippet comes back empty, which is the usual reason for a blank column.

```
snipexp:|pubid=(ra\-[\w\d]+)|i
```

### Phone numbers of pizzerias in Italy

`"href=\"tel" site:it pizza snipexp:|\"tel\:([^\"]+)\"|` (https://publicwww.com/websites/%22href%3D%5C%22tel%22+site:it+pizza+snipexp:%7C%5C%22tel%5C%3A(%5B%5E%5C%22%5D%2B%29%5C%22%7C/)

### AddThis publisher ids

`"addthis_widget.js#pubid=ra" snipexp:|pubid=(ra\-[\w\d]+)|i` (https://publicwww.com/websites/%22addthis_widget.js%23pubid%3Dra%22+snipexp:%7Cpubid%3D(ra%5C-%5B%5Cw%5Cd%5D%2B%29%7Ci/)

### WordPress plugin names

`"/wp-content/plugins/" snipexp:|/plugins/([\w\d\-\.\_]+)/|` (https://publicwww.com/websites/%22%2Fwp-content%2Fplugins%2F%22+snipexp:%7C%2Fplugins%2F(%5B%5Cw%5Cd%5C-%5C.%5C_%5D%2B%29%2F%7C/)

### Affiliate site ids

`"_pop.push([\"siteId" snipexp:|(siteId[\"\']\,\s*(\d+))|i` (https://publicwww.com/websites/%22_pop.push(%5B%5C%22siteId%22+snipexp:%7C(siteId%5B%5C%22%5C'%5D%5C%2C%5Cs*(%5Cd%2B%29%29%7Ci/)

Snippets are what the `csvsnippets` exports carry and what `snippets=1` returns from the [API](https://publicwww.com/docs/api/requests/). Extracting a field across a whole set of sites at once is what [clusters](https://publicwww.com/docs/clusters/) are for. Snippets are charged against a separate daily allowance - see [quotas and rate limits](https://publicwww.com/docs/api/limits/).

Source: https://publicwww.com/docs/query-syntax/regex/