instagram regex

def instacheck(name)

  unless /[a-z0-9._]{,30}/.match(name)
    return false
  end

  if /\.\./.match(name)
    return false
  end

  if /^\d+$/.match(name)
    return false
  end

  if /^\./.match(name)
    return false
  end

  true
end

Just a heads up for who came in from search engine.

As of May 2017, Instagram doesn't allow leading or trailing dot in the usernames, nor consecutive dots.

This regex by Jonathan Stassen works for me. Source http://blog.jstassen.com/2016/03/code-regex-for-instagram-username-and-hashtags

^([A-Za-z0-9_](?:(?:[A-Za-z0-9_]|(?:\.(?!\.))){0,28}(?:[A-Za-z0-9_]))?)$

@yizeng
Thank you very much!
I modified it a bit so it includes the @ sign (which it needs to do for my task) and works in R:

@([A-Za-z0-9_](?:(?:[A-Za-z0-9_]|(?:\\.(?!\\.))){0,28}(?:[A-Za-z0-9_]))?)

Best
Jonas

@yizeng and @JonasSchroeder

your regex not correct please modified for dot username like 'dreaming.of_makeup'

my modified:
^([A-Za-z0-9._](?:(?:[A-Za-z0-9._]|(?:\.(?!\.))){2,28}(?:[A-Za-z0-9._]))?)$

thank you!
kevin

that does not work for @jhon.potter :/

I needed to match and extract the username from instagram profile URL.
Built this myself and it works smooth:

(?<=instagram.com\/)[A-Za-z0-9_.]+

Checkout the demo here - regexr.com/5tbdb
You can modify characters as per your usecase.

Hello! How can I make this work with PHP´s preg_match() function? Thanks for help.

@verstecken You would pick one of several options in this thread and paste the regex into your function as per its manual page: https://www.php.net/manual/en/function.preg-match.php

Thanks, @technion I tried that before and didn't get it.
You will need to delimit your pattern with for example '/' in preg_match() and it is not explained on the functions manual website. Maybe a basic to know? Well, that`s why I asked here, because pasting the regex from above did not work straight. I found some info here: https://infoheap.com/php-regex-delimiter-examples/

If you want to get the username out of an instagram or twitter URL, in PHP, this works well:

$url = "https://instagram.com/some.username";
$pattern = "/(?:(?:http|https):\/\/)?(?:www\.)?(?:instagram\.com|instagr\.am|twitter\.com)\/([A-Za-z0-9-_\.]+)/im";

preg_match($pattern, $url, $matches);
echo $matches[1]; // Yeah! This returns "some.username"

My regex did no include any such characters. I can't comment on subsequent advice from anyone else. My code already checked for leading dots and did not fail any tests people brought up relating to someone elses code.