rails/rails — pull request #16383 by aantix (2014-08-03 06:48:56+00:00)
Title: Check if string is an integer or float

It's often helpful to be able to check whether a string contains a valid integer or float value, without having to resort to a full blown numericality validation.

```
"123".is_number? => true
"10.5".is_float? => true
"12.5".is_number? => true
"12.x".is_number? => false
```