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

Will negative values ever show up? Do values less than 1.0 have a leading zero or not? Will the values ever use scientific notation? — Phrogz
– Phrogz, Commented Jan 24, 2012 at 16:58

Phrogz · Accepted Answer · 2012-01-24 17:07:51Z

7

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.

edited Jan 24, 2012 at 17:07

answered Jan 24, 2012 at 16:58

Phrogz

304k115 gold badges669 silver badges758 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Bhushan Lodha Over a year ago

I used the second one ` str[ /\d+(?:\.\d+)?/ ]`. Thank you!

steenslag · Accepted Answer · 2012-01-24 20:21:47Z

6

No regex :

str.delete("^0-9.")

answered Jan 24, 2012 at 20:21

steenslag

80.2k16 gold badges144 silver badges174 bronze badges

Comments

Aliaksei Kliuchnikau · Accepted Answer · 2012-01-24 17:05:24Z

4

If your prices always have dollars.cents format (which is likely for prices) then use this regex:

"$ 9.0 / hr".match(/\d+\.\d+/)[0] # => 9.0
"$9.0/hr".match(/\d+\.\d+/)[0] # => 9.0

Else you should take regex from Phrogz answer.

edited Jan 24, 2012 at 17:05

answered Jan 24, 2012 at 16:57

Aliaksei Kliuchnikau

13.7k4 gold badges63 silver badges74 bronze badges

2 Comments

Phrogz Over a year ago

This requires the values to always have one decimal place; is that going to be true?

Aliaksei Kliuchnikau Over a year ago

@Pgrogz, yes, this is possible for prices, let's see what answer fits better for Bhushan's case.

dorsh · Accepted Answer · 2012-01-24 16:56:28Z

1

I don't know ruby, but the regex should be \d+(?:\.\d+)?. This will also work with "$9/hr"

answered Jan 24, 2012 at 16:56

dorsh

24.9k2 gold badges29 silver badges30 bronze badges

Collectives™ on Stack Overflow

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

4 Answers 4

1 Comment

Comments

2 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

1 Comment

Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related