From: Matthew Kerwin <lists@...>
Date: 2013-04-15T11:47:16+09:00
Subject: Re: simple lambda question

Hyun Oh K. wrote in post #1105634:
> below is python code.
[snip]
> and ruby have lambda func. so I hope easly solution make.
> anybody wellknown ruby user, help and solve above quiz.

You don't need lambdas to do this.  If you want to start simply, why not
just translate the python directly to ruby?

$ irb
irb:001:0> a=0
=> 0
irb:002:0> while a*a < 10000
irb:003:1>   if a*a > 1000
irb:004:2>     s = (a*a).to_s
irb:005:2>     if s[0]==s[1] and s[2]==s[3]
irb:006:3>       puts "#{a}, #{a*a}"
irb:007:3>     end
irb:008:2>   end
irb:009:1>   a = a+1
irb:010:1> end
88, 7744
=> nil

The next idiomatic step would be to use ruby's more functional block
methods.  As far as I understand it these aren't actually lambdas as
such, but I guess that's what you were talking about.  You can also
inline the inner-most `if' pretty easily as well.

$ irb
irb:001:0> 100.times do |a|
irb:002:1*   if a*a > 1000
irb:003:2>     s = (a*a).to_s
irb:004:2>     puts "#{a}, #{s}" if s[0]==s[1] and s[2]==s[3]
irb:005:2>   end
irb:006:1> end
88, 7744
=> 100

There's not much more I'd do with this particular snippet.

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