From: "林彰史" <hayashi.akifumi.sub@...>
Date: 2012-12-12T20:11:43+09:00
Subject: Enumerable#zip with File IO

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Hello,

I found strange behavior of Enumerable#zip, which I could not understand
why.
Appreciate if anyone can explain.

I wrote a short script below to see how Enumerable#zip method works with
File IO.

  file = open( ARGV[0], "r" )
  [1].zip( file.each ) do |n,l| puts "#{n}: #{l}" end
  [2].zip( file.each ) do |n,l| puts "#{n}: #{l}" end

Then, I provided it with a text file:

111
222
333

I expected that its output would be:

1: 111
2: 222

but actually got:

1: 111
2: 333

It looked like the second line of input was accidentally discarded.

If I replaced the arrays with ranges like:

  (1..1).zip( file.each ) do |n,l| puts "#{n}: #{l}" end
  (2..2).zip( file.each ) do |n,l| puts "#{n}: #{l}" end

then I got the expected result.

Ruby version is ruby 1.9.3p327 (2012-11-10 revision 37606)
[x86_64-darwin12.2.1].

Thanks in advance,
Hayashi

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<div>Hello,</div><div><br></div><div>I=A0found strange behavior of Enumerab=
le#zip, which I could not=A0understand why.</div><div>Appreciate if anyone =
can explain.</div><div><br></div><div>I wrote a short script below to see h=
ow Enumerable#zip method works with File IO.<br>
</div>



<div><br></div><div>=A0 file =3D open( ARGV[0], &quot;r&quot; )=A0</div><di=
v>=A0 [1].zip( file.each ) do |n,l| puts &quot;#{n}: #{l}&quot; end=A0</div=
><div>=A0 [2].zip( file.each ) do |n,l| puts &quot;#{n}: #{l}&quot; end=A0<=
/div><div>




<br></div><div>Then, I provided it with a text file:</div><div><br></div><d=
iv>111=A0</div><div>222=A0</div><div>333=A0</div><div><br></div><div>I expe=
cted that its output would be:</div><div><br></div><div>1: 111=A0</div>
<div>2: 222=A0</div><div>

<br></div><div>but actually got:</div><div><br></div><div>1: 111=A0</div><d=
iv>2: 333</div><div><br></div><div>It looked like the second line of input =
was accidentally discarded.</div><div><div><br></div></div><div>If I replac=
ed the arrays with ranges like:</div>




<div><br></div><div>=A0=A0(1..1).zip( file.each ) do |n,l| puts &quot;#{n}:=
 #{l}&quot; end=A0</div><div>=A0 (2..2).zip( file.each ) do |n,l| puts &quo=
t;#{n}: #{l}&quot; end=A0</div><div><br></div><div>then I got the expected =
result.</div>



<div><br></div><div>Ruby version is=A0ruby 1.9.3p327 (2012-11-10 revision 3=
7606) [x86_64-darwin12.2.1].</div><div><br></div><div>Thanks in advance,</d=
iv>
<div>Hayashi</div>
<div><br></div>

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