newbie question about blocks

[Jeppe Jakobsen]

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Hi, I want to square every element in my array using a block:

a =3D (1..1000).to_a
a.each {|x| x**2}

But this does not seem to work, it just outputs my array completely
unchanged

 

[dblack]

Hi --

Hi, I want to square every element in my array using a block:

a = (1..1000).to_a
a.each {|x| x**2}

But this does not seem to work, it just outputs my array completely
unchanged

What you want is map, rather than each:

a.map {|x| x**2 }

each just returns the receiver (i.e., the array itself). map returns
a new array, composed of the results obtained by running the block
once for each item.

"collect" is a synonym for map.


David

--
David A. Black ([email protected])
Ruby Power and Light (http://www.rubypowerandlight.com)

"Ruby for Rails" chapters now available
from Manning Early Access Program! http://www.manning.com/books/black

 

[Daniel Nugent]

The problem you're seeing is that :each doesn't do anything with the
return values of the block.

What you want is :map or :collect (or their destructive forms :map! or
:collect!).