Feature #9140: Allow each_with_index to get start index

• Status: Rejected
• Priority: Normal
• Assignee: Yukihiro Matsumoto

[Rodrigo Rosenfeld Rosas]

Is it possible for array.each_with_index(1){|el, i| ... } to be equivalent to array.each.with_index(1){...}?

Sometimes the application-domain index starts with 1, not 0. Currently each_with_index doesn't accept any arguments, so it wouldn't be backward incompatible if the start index defaults to 0.

[Yusuke Endoh]

Unfortunately, it is incompatible because "each_with_index" actually accepts arguments and passes them to "each".

$ ruby -rstringio -e 'StringIO.new("foo|bar|baz").each_with_index("|") {|s, i| p [s, i] }'
["foo|", 0]
["bar|", 1]
["baz", 2]

$ ruby -rstringio -e 'StringIO.new("foo|bar|baz").each("|").with_index(1) {|s, i| p [s, i] }'
["foo|", 1]
["bar|", 2]
["baz", 3]

When I made a proposal to make "with_index" accept an offset, matz determined to leave "each_with_index" as it is.

--
Yusuke Endoh [e-mail]

[Rodrigo Rosenfeld Rosas]

This is interesting because I noticed the *args in the documentation but it wasn't documented what it means. So I tried it but in a different context (adapting from your example):

%w(foo bar baz).each_with_index("|") {|s, i| p [s, i] }
ArgumentError: wrong number of arguments (1 for 0)
from (irb):3:in each'
from (irb):3:ineach_with_index'
from (irb):3
from /home/rodrigo/.rvm/rubies/ruby-2.0.0-p353/bin/irb:12:in `'

That's why I assumed it didn't accept any arguments.

[Rodrigo Rosenfeld Rosas]

Actually, it explains but I missed an example :) I do example driven development ;)

[Rodrigo Rosenfeld Rosas]

By the way, feel free to reject this ticket then. I only created it because I thought it would be backwards compatible.

[Zachary Scott]

So is this a doc bug?

On Nov 23, 2013, at 12:05 AM, "rosenfeld (Rodrigo Rosenfeld Rosas)" [e-mail] wrote:

Issue #9140 has been updated by rosenfeld (Rodrigo Rosenfeld Rosas).

By the way, feel free to reject this ticket then. I only created it because I thought it would be backwards compatible.

Feature #9140: Allow each_with_index to get start index
https://bugs.ruby-lang.org/issues/9140#change-43087

Author: rosenfeld (Rodrigo Rosenfeld Rosas)
Status: Open
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: lib
Target version:

Is it possible for array.each_with_index(1){|el, i| ... } to be equivalent to array.each.with_index(1){...}?

Sometimes the application-domain index starts with 1, not 0. Currently each_with_index doesn't accept any arguments, so it wouldn't be backward incompatible if the start index defaults to 0.

--
http://bugs.ruby-lang.org/

[Rodrigo Rosenfeld Rosas]

There's no bug. Just reject this feature request.

[Motohiro KOSAKI]

• Status changed from Open to Rejected