regex for combination of alphabets & numbers with Special characters for iOS

regex for combination of alphabets & numbers with Special characters for iOS


I want regex for iOS with following conditions,
1. there should be at-least one character or number in the string.
2. combination may contain special characters like !@#$%&* .
3. string length should be more than 7.

Eg.
test1234
test@1234
1234Test
Thanks in advance.