Find and Replace, or Re-Format

• cli: Search documentation
• vim: Find and replace in code
• rg (grep): Search through code, across directories
• js: fix malformed data (ex: Phone numbers)
• html: scrape websites

Regex is like salt: A little goes a long way, and a lot will put a bad taste in your mouth.

Regex is very terse - it's easy to write, but nearly impossible to read.

If you ever start using nested capture groups, or look-behinds, you may have gone down a dark path. You may need to stop.

Better to be adequate than to be a master.

Regular Expressions is basically a mini programming language unto itself, used for finding and replacing text.

• Literals
• Groups
• Quantities
• Ranges

Object/String form: new RegExp("Needle", "ig") will need double \\.

+1 (801) 555-1234
801-555-1234
18015551234
801.555.1234
801 555 1234

// replace all non-digit characters
var phone = "801.555.1234".replace(/\D/g, '');

// capture
var m = phone.match(/(1?)(\d{3})(\d{3})(\d{4})/)

console.log("+1 (" + m[2] + ") " + m[3] + "-" + m[4]);

// ZoOm.com                // match
// zoom.com.evilhacker.com // no match
// evilzoom.com            // no match
// www.zoom.com            // match

var goodsite = "ZoOm.com";
goodsite.match(/(^|.*\.)zoom\.com$/i)

Parse valid semver (doesn't reject invalid semver)

"v3.0.0-rc.1+abcdef"

"v3.0.0-rc.1+abcdef".match(/v?(\d+)\.(\d+)\.(\d+)(-([^+]*))?(\+(.*))/)

• rg

• vim
• grep