How to parse decimal numbers within a string

INPUT: a string containing decimal numbers.

OUTPUT: an array containing all the decimal numbers within the given string.

You can accomplish this task very quickly with the String#scan method and the right Regular Expression (regex).

Given a string s, you can use:

numbers = s.scan /[-+]?\d*\.?\d+/

numbers will be an array whose elements are the decimal numbers within the string s. Note how the regex considers the possible + or – signs in front of the numbers.

If you also wish to match floating point numbers with exponents (scientific notation, e.g. 2.54.e-07), then use the following:

numbers = s.scan /[-+]?\d*\.?\d+([eE][-+]?\d+)?/ 

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  1. Tore Darell February 12, 2006
  2. federico May 2, 2006
  3. Antonio Cangiano May 3, 2006