.times loop returns the number?

12.times do |month_ahead|
end

returns 12
I would have expected this to return a collected array of the return
value of each block. Odd?

On Jan 11, 2008, at 6:13 PM, Roger P. wrote:

12.times do |month_ahead|
end

returns 12
I would have expected this to return a collected array of the return
value of each block. Odd?

Posted via http://www.ruby-forum.com/.

Not odd at all.
x.times do |x|
code_here_using_x
end

In this iterating construct the current value passed in | | is the
current value of x.
other than that,
Ruby blocks always return the last value returned in the block.
if you simply do this:

x.times do |x|
code_here_using_x
puts “cat”
end

the block will return “cat”

The iterating constructs in Ruby are not always used to return a
value as in C-like languages.
They simply perform the code in the block a number of times.
This includes powerful and flexible concepts such iterating over
collections (arrays, hashes, etc…)

a = Array.new

a.each do |element|
some_function( element )
end

The main idea on iterators in ruby is the iterating!
But do keep in mind the simple convenience that Ruby code blocks
implicitly return the last value in the block.

a.each do |element|
some_function( element )
46
end

returns 46.
Sometimes that is useful and convenient.

On 1/11/08, John J. [email protected] wrote:

Ruby blocks always return the last value returned in the block.

true but…

if you simply do this:

x.times do |x|
code_here_using_x
puts “cat”
end

the block will return “cat”

But the whole expression won’t.

irb(main):001:0> irb(main):001:0> 5.times {|i| “a”}
=> 5
irb(main):002:0> 5.times {|i| puts “cat”}
cat
cat
cat
cat
cat
=> 5

And puts “cat” doesn’t return “cat”

irb(main):004:0> puts “cat”
cat
=> nil

On the other hand Integer#times is documented to return the integer:

qri Integer#times
---------------------------------------------------------- Integer#times
int.times {|i| block } => int


Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/

On Jan 11, 2008, at 7:13 PM, Roger P. wrote:

12.times do |month_ahead|
end

returns 12
I would have expected this to return a collected array of the return
value of each block. Odd?

To get a collected array:

(0…12).collect { |x| x * 2 }
=> [0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22]

Or via enumerators in Ruby 1.8:

require ‘enumerator’
=> true

12.enum_for(:times).collect { |x| x * 2 }
=> [0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22]

Or via Ruby 1.9’s new enumerator behavior:

12.times.collect { |x| x * 2 }
=> [0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22]

Gary W.

On Jan 11, 2008, at 5:13 PM, Roger P. wrote:

I would have expected this to return a collected array of the return
value of each block. Odd?

i often define this

class Numeric
def of &block
Array.new(to_i).map &block
end
end

list = 42.of{ those }

a @ http://codeforpeople.com/

Thank you!

Or via Ruby 1.9’s new enumerator behavior:

12.times.collect { |x| x * 2 }
=> [0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22]

Gary W.

That should be in the standard lib for coolness and ruby-ish-ness :slight_smile:

class Numeric
def of &block
Array.new(to_i).map &block
end
end

list = 42.of{ those }

a @ http://codeforpeople.com/

ara.t.howard wrote:

i often define this

class Numeric
def of &block
Array.new(to_i).map &block
end
end

Why not
Array.new(to_i, &block)
?

On Jan 12, 2008, at 2:07 PM, Roger P. wrote:

That should be in the standard lib for coolness and ruby-ish-ness :slight_smile:

class Numeric
def of &block
Array.new(to_i).map &block
end
end

list = 42.of{ those }

i’ve RCR’d it a few times, but i think the migrations have lost it
the mess… ;-(

a @ http://codeforpeople.com/

On Jan 12, 2008, at 2:28 PM, Sebastian H. wrote:

Why not
Array.new(to_i, &block)

just because i’ve been doing it since 1.6.8 :wink:

a @ http://codeforpeople.com/

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