Where can one find examples of masterful Ruby code?

Ruby
21

On Jun 3, 2006, at 3:48 PM, Alder G. wrote:

For example: check if integer i is a power of 2, with an expression no
more than 13 characters long.

Solution: (i & (i - 1))

Yuck. Thanks for reminding me that “masterful code” is definitely in
the eye of the beholder. :wink:

Out of the many suggestions raised in this thread, it seems that
following the Ruby Q. would be most appropriate. By such
participation much improvement might be gained. In such competitions,
the winning solutions are frequently required to be “masterful code”
according to the above definition.

Ruby Q. isn’t about “winning.” It’s just a collection of fun
exercises to keep us sharp. Everyone who plays or follows along is a
winner, in my opinion.

James Edward G. II

22

On Jun 3, 2006, at 4:48 PM, Alder G. wrote:

For example: check if integer i is a power of 2, with an expression no
more than 13 characters long.

Solution: (i & (i - 1))

I’m confused.

irb(main):001:0> i = 9
=> 9
irb(main):002:0> (i & (i - 1))
=> 8

So 9 is a power of 2?

As far as 13 characters goes

(i % 2).zero?

is exactly 13 characters and it gives a true or false answer
instead of zero of something else.

23

On 6/4/06, Logan C. [email protected] wrote:

is exactly 13 characters and it gives a true or false answer
instead of zero of something else.

It also tells you if i is a multiple of 2 :slight_smile:

24

On 6/3/06, James B. [email protected] wrote:

It may be like music, where the more one knows and the more one has
heard, the harder it is to get excited about new music (though when you
do find something good, it can be really exciting).

Never heard or thought this way. It would mean that the top musicians
are really bored by the music they play in concerts. I guess that the
more you know the more you are able to identify wonderful spot and
enjoy them.

./alex

25

On 6/3/06, Alder G. [email protected] wrote:

For example: check if integer i is a power of 2, with an expression no
more than 13 characters long.

Solution: (i & (i - 1))

Note that this solution is not only very concise, but also (on any
reasonable implementation) very fast. Masterful code has a tendency to
be “correct” in many ways.

Thanks for this very useful snippet. It was worth reading the thread
for.

Probably should be methodized as:
def powerof2?( i )
(i & (i - 1))==0
end

Of course it’s not immediately obvious from reading the code how it
works till you try an example:

1000 #8 in binary
0111 #7 in binary
&----------
0000

…so maybe readability isn’t always part of the criteria for
‘masterful’ code. I do think that the way you’ve done it is the
fastest way to figure out if an integer is a power of 2 and after you
work through an example it does seem quite elegant.

Phil

26

Logan C. wrote:

On Jun 3, 2006, at 4:48 PM, Alder G. wrote:

For example: check if integer i is a power of 2, with an expression no
more than 13 characters long.

Solution: (i & (i - 1))

I’m confused.

irb(main):001:0> i = 9
=> 9
irb(main):002:0> (i & (i - 1))
=> 8

So 9 is a power of 2?

As far as 13 characters goes

(i % 2).zero?

is exactly 13 characters and it gives a true or false answer
instead of zero of something else.

Actually you have to compare with zero to get the expected result as
a previous poster posted:

def powerof2?( i )
(i&(i-1))==0
end

(i&(i-1))==0 counts to twelve characters.

i%2 determines odd or even.

powerof2?(9) => false
powerof2?(16) => true

/christer

27

Alexandru P. wrote:

enjoy them.
Well, for myself, the music I like to listen to, and the music I like to
write, and the music I like to play, are different sets with only
partial overlap.

For example, I like a lot of droning, repetitive, minimalist music, but
hate playing it. And I like playing, say, songs in the vein of the Sex
Pistols, but have no interest in writing anything that sounds like
that.

In my code/music metaphor I was thinking more of what I find interesting
to listen to; less and less makes a big impression on me (though this
could just be a sign that I’m turning into my parents).

I suspect that with various programming languages, as you internalize
the idioms, you’re less struck by how clever something is; you may
think, “That’s just how it’s done.”

There’s less novelty for you to misinterpret as mastery.

–
James B.

http://web2.0validator.com - We’re the Dot in Web 2.0
http://refreshingcities.org - Design, technology, usability
http://yourelevatorpitch.com - Finding Business Focus
http://www.jamesbritt.com - Playing with Better Toys

28

On Jun 3, 2006, at 6:39 PM, Christer N. wrote:

(i % 2).zero?

–
Posted via http://www.ruby-forum.com/.

I was trying to make a point. Unfortunately for my point making, I
misunderstood the function. I was trying to come up with a reasoned
argument for this but I can’t, and my example sucked. So I just want
to say “(n & (n - 1)) is icky.”

29

Alder G. wrote:

For example: check if integer i is a power of 2, with an expression no
more than 13 characters long.

Solution: (i & (i - 1))

0 is a power of 2?

–

Ray

30

On 6/4/06, James B. [email protected] wrote:

more you know the more you are able to identify wonderful spot and
In my code/music metaphor I was thinking more of what I find interesting
to listen to; less and less makes a big impression on me (though this
could just be a sign that I’m turning into my parents).

I suspect that with various programming languages, as you internalize
the idioms, you’re less struck by how clever something is; you may
think, “That’s just how it’s done.”

So, what you are trying to say is that by the time you may become
blase. If so, than where is the passion? Has all burnt down? Going
back to code/music metaphor, this would translate that most of the
composers would just stop composing because they have enough. And I
really cannot agree with this.

There’s less novelty for you to misinterpret as mastery.

It looks like we are having a different perspective/interpretation of
mastery. And probably, we should agree to disagree. For me a
masterpiece will still be a masterpiece, whatever my understanding
level will be.

best regards,

./alex

.w( the_mindstorm )p.

Probably, we have different perception/interpretation of ‘mastery’.

31

On Jun 3, 2006, at 6:17 PM, Ray B. wrote:

Alder G. wrote:

For example: check if integer i is a power of 2, with an
expression no
more than 13 characters long.
Solution: (i & (i - 1))

0 is a power of 2?

2^negative_infinity

add a special case if you like.

– Elliot T.

32

Alexandru P. wrote:

On 6/4/06, James B. [email protected] wrote:

So, what you are trying to say is that by the time you may become
blase.

No; that’s too cynical. I’m saying that naivety distorts appreciation.

I expect that 99% of the people on this list have gone back to look at
code they wrote some time ago, code they were quite proud of at the
time, and cringed. Or created what they think is some neat hack, rushed
of to show their more experienced co-workers, only to learn that they’ve
finally discovered a common idiom of the language. Acquiring a more
critical judgment is not being blase.

If so, than where is the passion? Has all burnt down?

“I don’t care for it” is not the same as “I don’t care.”

There’s a difference between judging something to be crap, and believing
that it must be that way by necessity.

Going
back to code/music metaphor, this would translate that most of the
composers would just stop composing because they have enough. And I
really cannot agree with this.

Well, that’s a misreading of what I wrote. Composers may be more driven
as they learn more, because the challenge gets harder, while expereinced
listeners have a diminissed tolerance for crap, because over time poor
music doesn’t bear up. So they demand better.

There’s less novelty for you to misinterpret as mastery.

It looks like we are having a different perspective/interpretation of
mastery. And probably, we should agree to disagree. For me a
masterpiece will still be a masterpiece, whatever my understanding
level will be.

But the ability to recognize a masterpiece should change with your level
of understanding, and that’s my point. People looking for masterful
code need some frame of reference both to spot it and to appreciate it.

Asking for examples of masterful code is only half the journey.

Growing up, people told me about masterful composers, and I listened to
their works, but it was only years later, after exposure to a lot of
music, that I could really appreciate what made a work great (or not).

–
James B.

“The greatest obstacle to discovery is not ignorance, but the illusion
of knowledge.”

  • D. Boorstin
33

On Jun 4, 2006, at 2:47 AM, Robert K. wrote:

Wow, this actuall works in Ruby:

irb(main):004:0> -1.0/0
=> -Infinity
irb(main):007:0> 2 ** (-1.0/0)
=> 0.0

maybe that’s a rounding error?

irb(main):009:0> 2 ** (-2 ** 11)
=> 0.0

irb(main):008:0> 2.0 ** (-2.0 ** 11.0)
=> 0.0

(i’m not sure exactly how conversion to floats works, hence 2 versions)

– Elliot T.

34

2006/6/4, Elliot T. [email protected]:

0 is a power of 2?

2^negative_infinity

Wow, this actuall works in Ruby:

irb(main):004:0> -1.0/0
=> -Infinity
irb(main):007:0> 2 ** (-1.0/0)
=> 0.0

add a special case if you like.

… and violate the 13 character constraint. :slight_smile:

robert