Require Math

ruby-talk
1

I need to access the sqrt method in my rails app. I believe I need the
Math library for this:

irb(main):010:0> require "Math"
LoadError: no such file to load -- Math

Could someone tell me where I download the Math library from, and where
I should place it on my file system? I can't seem to find any
documentation explaining this.

Lindsay

···

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2

It is already there, you can call it in a couple of ways:

puts Math.sqrt(2)

or if you want a lot of Math methods you can use include to get the Math module's methods without the Math prefix:

include Math
puts sqrt(2)

You should read up on what include does before using it.

Hope this helps,

Mike

···

On 23-Mar-06, at 6:38 AM, Lindsay Boyd wrote:

I need to access the sqrt method in my rails app. I believe I need the
Math library for this:

irb(main):010:0> require "Math"
LoadError: no such file to load -- Math

Could someone tell me where I download the Math library from, and where
I should place it on my file system? I can't seem to find any
documentation explaining this.

--

Mike Stok <mike@stok.ca>
http://www.stok.ca/~mike/

The "`Stok' disclaimers" apply.

3

Thanks Mike - I was trying '2.sqrt'. No wonder that didn't work!

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4

Lindsay Boyd:

Thanks Mike - I was trying '2.sqrt'. No wonder that didn't work!

Yeah, I've always wanted to do that kind of thing, too... let's try this:

class Numeric
  Math.methods(false).each do |m|
    define_method(m) {|*args| Math.send(m, self, *args) }
  end
end

2.sqrt #=> 1.4142135623731

Floating-pointilicius!

Cheers,
Dave

5

2.sqrt #=> 1.4142135623731

That's really elegant. I can see why Ruby has so many fans :slight_smile:

Lindsay

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