regex and readme yo

python/7-regex-intro/README.md

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+Regular Expressions
+===================
+
+Regular Expressions (regex for short) are a way to represent patterns in strings. They aren't as bad as people make them out to be. When used on the right problem, they are a great solution.
+
+Go to [Rubular](http://rubular.com/). We're going to sandbox inside it a bit to get acquainted with regex syntax. At the bottom of the page is a regex cheat sheet.  
+Note: Depending on the language, you may have to escape certain characters. For example, instead of `a{3}`, you may have to type `a\{3\}`.  
+Also, be careful with periods (`.`). A period means any character in regex, so you have to escape it if you want to pattern match a period.
+
+Here are some examples of regex and matching string patterns:  
+* `a{3}` => `aaa`
+* `a{3,}` => `aaaaaaaa`
+* `[a-z]` => any lowercase letter
+* `[A-Z]{4,6}` => between 4 and 6 uppercase letters, ex. `FASDV`
+* `.` => any character
+* `\w\.` => `_.`
+* `hello\d?` => `hello` or `hello5`
+* `[a-nO-Z]*` => abcOZZ
+
+Make a regex to match each of these strings:  
+* match 'byte academy' 3 different ways
+* an 8 character password, do not allow non word characters
+* an 8 character password that has at least 1 number and 1 capital letter
+
+
+* byteacademy@example.com
+* byte.academy@example.com
+* byteacademy22@example.co.uk  
+See if you can get all three with 1 regex, but not invalid emails (not having an @, etc...)