Valid Number

A valid number can be split up into these components (in order):

1. A decimal number or an integer.
2. (Optional) An 'e' or 'E', followed by an integer. A decimal number can be split up into these components (in order):
3. (Optional) A sign character (either '+' or '-').
4. One of the following formats:
5. One or more digits, followed by a dot '.'.
6. One or more digits, followed by a dot '.', followed by one or more digits.
7. A dot '.', followed by one or more digits. An integer can be split up into these components (in order):
8. (Optional) A sign character (either '+' or '-').
9. One or more digits. For example, all the following are valid numbers: [ "2 ", "0089 ", "-0.1 ", "+3.14 ", "4. ", "-.9 ", "2e10 ", "-90E3 ", "3e+7 ", "+6e-1 ", "53.5e93 ", "-123.