Month: March 2005

Day 3 is all about strings, arrays, hashes, and ranges – abstract, geeky terms for buckets

In Ruby, strings can be treated like arrays. Meaning it’s super easy to access substring. For example:

theString = "It's raining today"
theString[13, 5] # returns ‘today’

Finally, I always thought substr() methods were an awkward solution for something so common.

Replacing substrings is just as easy:

theString["today"] = "still"# theString is now “it’s raining still”

All this talk about strings reminds me, Ruby knows the alphabet. Makes me smile just thinking about it.
"a".next # returns “b”

I’ve written a couple plugins (WP-CaTT, WP-iCal) for WordPress. Developing each one of them has sent me digging through PHP’s function list more frequently than I’d like – looking for just the right function. I’ve rewritten Perl apps in PHP to make the more readable and maintainable. As I’m learning more about the Ruby syntax, PHP feels like Perl.

Here’s a Super Useful Thing: Ruby can grep arrays. Need the list of months you can eat mussels in, if months_in_year was an array of months, this would work:
months_in_year.grep(/r/) # returns all months with an “r” in their name

I’d like to thank Slagell for explaining the difference between arrays and hashes in a useful way.

Back in day one, we talked about the Principle of Least Surprise. So far, getting through the end-of-chapter exercises has been a matter of applying that principle.

I was scanning the pages in today’s chapter looking for the method to flatten an array. According to the Principle of Least Surprise the method would be ‘flatten’. It is. 🙂

Al Abut’s 3rd day

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This post documents my journey through Sam’s Teach Yourself Ruby in 21 days. I’ll be joining Al Abut in his effort to learn Ruby and blog along the way.

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Day 2 starts with one of the most valuable programming exercises. What can I do with an object? Just ask it:


self.methods


With ‘self’ being the current object, the above question returns a list of all the questions ‘self’ knows how to answer.

Every object in Ruby can be asked this question. So many languages are only object-oriented, not object-saturated like Ruby. Back in my REALbasic days, I’d scan an objects auto-complete menu looking for the right method or attribute. More than once I was baffled in the differences between objects. I was also baffled by the difference between ‘self.’ and ‘me.’ in RB. No sign of ‘me.’ yet in Ruby.

If you ask 10 people “What is your name?”, you’ll receive 10 different answers. In programming, this is called ‘polymorphism’ and it means different objects can respond differently to the same question. A useful example comes from Object-Oriented Thought Process: all shapes – circles, squares, triangles – have a perimeter and an area. Thought the equation to calculate each is different.

Occasionally, I’ll hit a programming problem where it makes sense to return multiple values out of a method. Normally, I take this as a cue I’m not being clear about what I’m trying to accomplish and make 2 methods. Looks like Ruby can return multiple values separated by commas. Seems useful for debugging.

The Ruby syntax is truly Zen-like. No semi-colons explicitly declaring the end of a line made me smile. Now Slagell’s saying ‘return’ at the end of a method isn’t needed either. Without an explicit ‘return’, the last thing evaluated is returned.

me.jump(up, down)

Here’s a useful tip I learned going through today’s exercises. Between 2 datetime strings, Ruby doesn’t know what ‘+’ means. For example:

return Time.now + Time.now

returns an error, where as

return "it's #{Time.now}" + ", now it's #{Time.now}."

spits out a sentence.

Good to know.

Al Abut’s 2nd day

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This post documents my journey through Sam’s Teach Yourself Ruby in 21 days. I’ll be joining Al Abut in his effort to learn Ruby and blog along the way.

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Mark Slagell’s writing style is conversational and educational. I’ve gone through a number of software language tutorials. I found Slagell’s first chapter a comfortable mix of background info, simple examples, and experiments.

On the outset, Slagell states Ruby is based on the:

Principle of Least Surprise:
“If you don’t know how to do something and you try to say clearly what you mean, there’s a good chance it will work.”

This principle’s more descriptive if less sexy moniker is the principle of maximum boredom.

The remainder of Day 1 is examples proving his point.

Al Abut’s first day

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This post documents my journey through Sam’s Teach Yourself Ruby in 21 days. I’ll be joining Al Abut in his effort to learn Ruby and blog along the way.

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