Meta-characters. There are special characters in regular expressions, some of them include: d matches any digit, equivalent to [0-9]; D matches any character that’s not a digit, equivalent to ...

JavaScript’s RegExp object, which holds a regular expression, is what we need here. Regular expressions are a big subject, and there are plenty of FAQs on them on the Web.

Use popular 'grammar of data' syntax to filter and subset your two-dimensional JavaScript arrays and more. Here's how to use Arquero for data wrangling in Observable JavaScript and Node.js.