How do I round to two decimal places?

Question

I want any items that are rounded such as this:

(5.101 * 100).round / 100.0

To be output like this:

5.10

Instead of this:

5.1

How do I do this in Ruby?

score 16 · Accepted Answer · answered Aug 01 '13 at 04:58

16

There are a couple ways, but I favor using String's % (format) operator:

'%.2f' % [(5.101 * 100).round / 100.0] # => "5.10"

Kernel's sprintf method has the documentation for the various flags and modifiers. There's also Kernel's printf but, like I said, I'd go with %.

answered Aug 01 '13 at 04:58

the Tin Man

155,156
41
207
295

And? You're concerned because floating point isn't accurate? http://stackoverflow.com/q/10721739/128421 – the Tin Man Apr 05 '16 at 18:38
1

That's good, but your comments are not applicable to this question. – the Tin Man Apr 05 '16 at 18:56
I see, it is about rounded numbers. Removing ... Thank you – Anwar Apr 05 '16 at 19:00

score 8 · Answer 2 · answered Aug 01 '13 at 05:53

8

I hope it will help you.

2.0.0p195 :002 > (52.452158744).round(2)
=> 52.45 
2.0.0p195 :003 > (20.452158744).round(2)
=> 20.45 
2.0.0p195 :004 > (20.002555).round(2)
=> 20.0 
2.0.0p195 :005 > (20.012555).round(2)
=> 20.01

answered Aug 01 '13 at 05:53

Pravin Mishra

7,934
4
35
48

`(5.0).round(2)` returns `5.0` instead of `5.00` – Anwar Apr 05 '16 at 18:23
7

`(5.0).round(2)` does rounding. It doesn't do formatting. They're different. – the Tin Man Apr 05 '16 at 18:43

How do I round to two decimal places?

2 Answers2