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![Alejandra Estefanía Aguilera Ávila](https://uploads.teamtreehouse.com/production/profile-photos/11459278/micro_IMG_20190331_151919.jpg)
Alejandra Estefanía Aguilera Ávila
6,865 PointsI don't quite understand the ASCII thing
Hi,
Can somebody explain to me how that works, how do you know which symbols to use? I think Kenneth just supposed everyone knew this and he doesn't elaborate much on that...
Thanks!
1 Answer
![Steven Parker](https://uploads.teamtreehouse.com/production/profile-photos/969492/micro_tool_chess_set_2.jpg)
Steven Parker
230,688 PointsThe reference to "ASCII" just means that he's using ordinary characters instead of fancy (unicode) characters. The regex character class shown covers upper case letters (A-Z), lower case letters (a-z), numbers (0-9) and the underscore (_).