From: Robert Klemme <shortcutter@...>
Date: 2007-03-03T18:40:06+09:00
Subject: Re: String.each

On 03.03.2007 09:00, Robert Dober wrote:
> On 3/3/07, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
>> On Sat, 3 Mar 2007, Yannick Grams wrote:
>>
>> > Hello all!
>> >
>> > I'm fairly new to Ruby, and I'm trying to write a program that looks at
>> > each character of a string and then processes it using a block. I've
>> > been using:
>> >
>> > String.each do
>> >   #block
>> > end
>> >
>> > but something isn't working. I'm sure that there is a simple answer, 
>> but
>> > I'm not that experienced with the language. If someone could please 
>> help
>> > me out, I'd greatly appreciate it.
>> >
>> > --
>> > Posted via http://www.ruby-forum.com/.
>>
>> harp: ~> ri String#each
>> ------------------------------------------------------------ String#each
>>       str.each(separator=$/) {|substr| block }        => str
>>       str.each_line(separator=$/) {|substr| block }   => str
>> ------------------------------------------------------------------------
>>       Splits _str_ using the supplied parameter as the record separator
>>       (+$/+ by default), passing each substring in turn to the supplied
>>       block. If a zero-length record separator is supplied, the string is
>>       split on +\n+ characters, except that multiple successive newlines
>>       are appended together.
>>
>>          print "Example one\n"
>>          "hello\nworld".each {|s| p s}
>>          print "Example two\n"
>>          "hello\nworld".each('l') {|s| p s}
>>          print "Example three\n"
>>          "hello\n\n\nworld".each('') {|s| p s}
>>
>>       _produces:_
>>
>>          Example one
>>          "hello\n"
>>          "world"
>>          Example two
>>          "hel"
>>          "l"
>>          "o\nworl"
>>          "d"
>>          Example three
>>          "hello\n\n\n"
>>          "world"
>>
>>
>> harp:~ > ruby -e'  puts String.instance_methods.grep(/each/)  '
>> each
>> each_with_index
>> each_line
>> each_byte
>>
>>
>> harp:~ > ruby -e'  "foobar".each_byte{|b| p b}  '
>> 102
>> 111
>> 111
>> 98
>> 97
>> 114
>>
>>
>> harp:~ > ruby -e'  "foobar".each_byte{|b| p b.chr}  '
>> "f"
>> "o"
>> "o"
>> "b"
>> "a"
>> "r"
>>
>>
>> -a
>> -- 
>> be kind whenever possible... it is always possible.
>> - the dalai lama
>>
>>
> 
> I'd like to add two remarks
> (1) ruby -e'  "foobar".split("").each{|b| p b} '
> and
> (2) I feel it is a pity that
> s.each("") is not the same as s.split("").each
> and

Yeah, String's enumeration is a bit weird and inconsistent.  Using a 
String as array of lines does have it's uses at times but I wonder 
whether changing #each to return characters would be more useful (apart 
from breaking existing code).

> (3)
> "foobar".to_a does not deliver "foobar".split(""). The Arrayness of
> String might even indicate that String#to_a return an array of bytes
> as delivered by #[index]?
> Note that the easiest way to do this ( which I found ) was
> 
> x=[]; each_byte{ |b| x << b}; x

There's also

irb(main):014:0> require 'enumerator'
=> true
irb(main):015:0> "foobar".to_enum(:each_byte).to_a
=> [102, 111, 111, 98, 97, 114]

Kind regards

	robert