How to write a regex to extract numeric values from a string?

Question

I have a string str = "$ 9.0 / hr" or str = "$9.0/hr". I only want the integer value from this in this case 9.0

Language is Ruby 1.9.2

Answer 1

I'd use:

number = str[ /\d*(?:\.\d+)?/ ]

Or, if a leading 0 is required for values less than 1.0,

number = str[ /\d+(?:\.\d+)?/ ]

If you might have other numbers in the string, and only want the (first) one that has a dollar sign before it:

number = str[ /\$\s*(\d+(?:\.\d+)?)/, 1 ]

If it's guaranteed that there will (must) be a decimal place and digit(s) thereafter:

number = str[ /\$\s*(\d+\.\d+)/, 1 ]

Hopefully you can mix and match some of these solutions to get what you need.