From: "Michael T. Richter" <ttmrichter@...>
Date: 2008-05-07T20:38:53+09:00
Subject: Re: Interesting result of a newbie mistake

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On Wed, 2008-05-07 at 20:10 +0900, VICTOR GOLDBERG wrote:

> Instead of writing
> a =3D %w{ ant cat dog }
> I wrote
> a =3D %{ ant cat dog }
> puts a[2]        -->        110



> I didn't find an explanation for this result in Dave Thomas' book
> Anybody volunteers a response?


irb(main):001:0> a =3D %{ ant cat dog }
=3D> " ant cat dog "
irb(main):002:0> a[2]
=3D> 110
irb(main):003:0> a =3D %w{ ant cat dog }
=3D> ["ant", "cat", "dog"]
irb(main):004:0> a[2]
=3D> "dog"

They're different types.  The first one came back as the string " ant
cat dog " while the second came back as an array with three strings
["ant","cat","dog"].  One of the principles of least surprise in Ruby is
that indexing a string gives you the integer value of the character at
that location.  (I may be using a bit of sarcasm with that "principle of
least surprise" thing there....)  So a[0] is 32 (the ASCII encoding for
a space), a[1] is 97 (for "a") and a[2] is 110 (for "n").  If you do it
the right way (for your purposes, I mean) a[0] is "ant", a[1] is "cat"
and a[2] is "dog".

--=20
Michael T. Richter <ttmrichter@gmail.com> (GoogleTalk:
ttmrichter@gmail.com)
Those who have learned from history are bound to helplessly watch it
repeat itself. (Albert Y. C. Lai)

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On Wed, 2008-05-07 at 20:10 +0900, VICTOR GOLDBERG wrote:
<BLOCKQUOTE TYPE=3DCITE>
<PRE>
<FONT COLOR=3D"#000000">Instead of writing</FONT>
<FONT COLOR=3D"#000000">a =3D %w{ ant cat dog }</FONT>
<FONT COLOR=3D"#000000">I wrote</FONT>
<FONT COLOR=3D"#000000">a =3D %{ ant cat dog }</FONT>
<FONT COLOR=3D"#000000">puts a[2]        --&gt;        110</FONT>
</PRE>
</BLOCKQUOTE>
<PRE>

</PRE>
<BLOCKQUOTE TYPE=3DCITE>
<PRE>
<FONT COLOR=3D"#000000">I didn't find an explanation for this result in Dav=
e Thomas' book</FONT>
<FONT COLOR=3D"#000000">Anybody volunteers a response?</FONT>
</PRE>
</BLOCKQUOTE>
<BR>
irb(main):001:0&gt; a =3D %{ ant cat dog }<BR>
=3D&gt; &quot; ant cat dog &quot;<BR>
irb(main):002:0&gt; a[2]<BR>
=3D&gt; 110<BR>
irb(main):003:0&gt; a =3D %w{ ant cat dog }<BR>
=3D&gt; [&quot;ant&quot;, &quot;cat&quot;, &quot;dog&quot;]<BR>
irb(main):004:0&gt; a[2]<BR>
=3D&gt; &quot;dog&quot;<BR>
<BR>
They're different types.&nbsp; The first one came back as the string &quot;=
 ant cat dog &quot; while the second came back as an array with three strin=
gs [&quot;ant&quot;,&quot;cat&quot;,&quot;dog&quot;].&nbsp; One of the prin=
ciples of least surprise in Ruby is that indexing a string gives you the in=
teger value of the character at that location.&nbsp; (I may be using a bit =
of sarcasm with that &quot;principle of least surprise&quot; thing there...=
.)&nbsp; So a[0] is 32 (the ASCII encoding for a space), a[1] is 97 (for &q=
uot;a&quot;) and a[2] is 110 (for &quot;n&quot;).&nbsp; If you do it the ri=
ght way (for your purposes, I mean) a[0] is &quot;ant&quot;, a[1] is &quot;=
cat&quot; and a[2] is &quot;dog&quot;.<BR>
<BR>
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-- <BR>
<B>Michael T. Richter</B> &lt;<A HREF=3D"mailto:ttmrichter@gmail.com">ttmri=
chter@gmail.com</A>&gt; (<B>GoogleTalk:</B> ttmrichter@gmail.com)<BR>
<I>Those who have learned from history are bound to helplessly watch it rep=
eat itself. (Albert Y. C. Lai)</I>
</TD>
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