From: john_sips_tea@...
Date: 2006-03-27T07:43:54+09:00
Subject: Re: deciphering poignant guide chapter 4 example

> First, let me warn you that from what you describe, you have
> a Python viewpoint on the data structures and that it is quite
> different from many many languages.

Well, hopefully you folks can help straighten me out then. :)

I've actually programmed in C, C++, Java, Perl, and Python,
but my trouble is that as soon as I learn the next language,
my brain tries to file previous language knowledge into
my grey matter's round filing cabinet. :)

> As you seem to come from the Python's world, you probably
> know that Python's strings are immutable. And if you read a
> little bit about why strings in Python are immutable, you will
> see it's because they wanted to optimize the method lookup.

I'll have to think about that. I don't see the connection between
strings and method lookup. In Python code, you write a name(),
and python works its way up the inheritance tree looking for
the function definition. You can't call a method like:

def my_func():
    print "hi"
foo = "my_func"
foo()  # Trying to call my_func, but it fails.

so I don't see the string/method-call connection you're
referring to...

> In the end, Python's string are what's called in Ruby Symbol
> and Ruby's strings have no equivalent in Python, as Python
> has no mutable string class.

Ah! Thanks.

> You can expand it like that :
>
> sorted_kitty = kitty_toys.sort_by { |toy| toy[:shape] }
> sorted_kitty.each do |toy|
>   [...]
> end

Got it.

> The ruby equivalent of your python code would be :
>
> (1...8).each { |i|  (1...4).each { |j| puts i,j} }

Ah. Sweet. Thanks for throwing that in. :)