Pass a function by name in Ruby

Question

How can you pass a function by name in Ruby? (I've only been using Ruby for a few hours, so I'm still figuring things out.)

nums = [1, 2, 3, 4]

# This works, but is more verbose than I'd like    
nums.each do |i|
  puts i
end

# In JS, I could just do something like:
# nums.forEach(console.log)

# In F#, it would be something like:
# List.iter nums (printf "%A")

# In Ruby, I wish I could do something like:
nums.each puts

Can it be done similarly concisely in Ruby? Can I just reference the function by name instead of using a block?

People voting to close: Can you explain why this isn't a real question?

Is that what you're looking for? stackoverflow.com/questions/522720/… — Glauco Vinicius
– Glauco Vinicius, Commented Dec 10, 2012 at 21:25

Chris Schmich · Accepted Answer · 2012-12-10 21:33:43Z

6

You can do the following:

nums = [1, 2, 3, 4]
nums.each(&method(:puts))

This article has a good explanation of the differences between procs, blocks, and lambdas in Ruby.

answered Dec 10, 2012 at 21:33

Chris Schmich

29.6k5 gold badges79 silver badges94 bronze badges

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

1 Comment

Chris Schmich Over a year ago

It's also possible to specify an instance method, e.g. nums.each(&$stderr.method(:puts))

zetetic · Accepted Answer · 2012-12-10 21:34:46Z

3

Can I just reference the function by name instead of wrapping it in a block?

You aren't 'wrapping' it -- the block is the function.

If brevity is a concern, you can use brackets instead of do..end:

nums.each {|i| puts i}

answered Dec 10, 2012 at 21:34

zetetic

47.6k10 gold badges114 silver badges119 bronze badges

Comments

Dave Newton · Accepted Answer · 2012-12-10 21:37:05Z

0

Not out-of-the-box, although you can use method:

def invoke(enum, meth)
  enum.each { |e| method(meth).call(e) }
end

I prefer it wrapped up into a monkeypatched Enumerable.

There are other ways to go about this, too; this is kind of brute-force.

answered Dec 10, 2012 at 21:37

Dave Newton

161k27 gold badges263 silver badges310 bronze badges

Collectives™ on Stack Overflow

Pass a function by name in Ruby

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related