Showing username from ID

[TheFakeEscape]

Hey,

I'm doing some site integration and I'm building a comments system, obviously it's using the vBulletin database for the users.

Example:
1 - Bob
2 - Bill

Bob is browsing the website, the below two lines will show his user ID or his Username

PHP Code:

$vbulletin->userinfo['userid']; 


This displays: 1

PHP Code:

$vbulletin->userinfo['username']; 


This displays: Bob

However, when Bill views the website it'll show his name instead of Bob. I thought the following would work, and show any username from the ID I put in

PHP Code:

$vbulletin->userinfo['1']; 


I want something like this, to show 'Bob' as he's user '1'

Obviously it doesn't work, does anyone know how to display a Username from an ID?