Regex with numbers, letters and space

Hi, I would like to ask if there is a regex syntax that helps replace unwanted characters and keep only alphabets, numbers and spaces.

Eg. This String would become 2018 STR Summer Intern Training <<China Power - Towards a Mondernised Power Market>> to 2018 STR Summer Intern Training China Power Towards a Mondernised Power Market

I hope this thread helps a little:
https://stackoverflow.com/questions/6053541/regex-every-non-alphanumeric-character-except-white-space-or-colon