记不太请那是在大学年级了，系里举办班级足球赛，我们班集体选择了阿根廷队的队服，喜欢这种蓝白剑条衫，喜欢整体的颜色搭配，记得那时参加了两场比赛，第一场比赛打右前卫助攻一球，第二场比赛脚脖严重扭伤，休息了一个月有余。这套球服一直伴随这我，今晚收拾衣柜，又把它翻了出来，真是越看越喜欢，遂拿出来秀一下。^_^

下面就是我的阿根廷队队服：

明天晚上23点，阿根廷在本届世界杯的四分之一决赛就要面对东道主德国队了，虽然遇到东道主不是什么好消息，但是我仍然坚定的支持阿根廷队，相信他们一定能打入决赛，捧起大力神杯的！里克尔梅，加油！梅西，加油！阿根廷队，加油！

在2005年初曾经写过一篇文章叫'结识Ruby'，当时的确是刚刚结识Ruby这种语言，好奇心使然，遗憾的是之后没有坚持学习下去，也就是在这一年Ruby获得了很大的发展，特别是Ruby On Rails的出现让Ruby一下成为新兴语言的代表，甚至有人预言Ruby将会成为Java的替代者成为下一代主流语言。无论如何，Ruby的日益被广大开发人员所接受是个不争的现实，就连Martin Fowler到中国讲'敏捷'时都向中国的开发人员推荐Ruby。大师都开始学习和使用Ruby了，我们还等什么呢？有空儿的时候就多学学吧。

单纯的从学习Ruby语法的角度来看，有一个交互式学习的站点很是不错－TryRuby，感觉通过TryRuby学习Ruby基础语法就像是在玩类似'仙剑奇侠传'那种RPG游戏，有Tutorial一步一步指导你'过关'，而在'过关'的过程中，Ruby相关的基础就印在你的大脑中了。

这里我把在'TryRuby'的过关过程记录下来，当然Tutorial中的一些英文说明这里被我粗略翻译为中文了：

try typing some math. Like: 2 + 6
>> 2 + 6
=> 8

Ruby能识别数字和数学符号，try some other math：
>> 4 * 10
=> 40

>> 5 – 12
=> -7

>> 40 / 10
=> 4

计算机处理数学方便快捷，我们继续，我们来看看倒转你的名字，象这样"Jimmy"输入你的名字：
>> "Tony"
=> "Tony"

一个字符串是一个计算机能够处理的字符集合，引号标识字符串的首尾，如果想翻转你的名字，敲入"Jimmy".reverse
>> "Tony".reverse
=> "ynoT"

让我们看看你的名字中到底有多少个字母："Jimmy".length
>> "Tony".length
=> 4

看这个，我们将你的名字乘以5. "Jimmy" * 5
>> "Tony" * 5
=> "TonyTonyTonyTonyTony"

我们来看看第一分钟学到了什么。
(1) Numbers and strings are Ruby's math and text objects.
(2) Methods. You've used English-language methods like reverse and symbolic methods like * (the multiplication method.)

Methods are action!

让我们做些uncomfortable的事情，尝试翻转一个数字：40.reverse

>> 40.reverse
=> NoMethodError: undefined method `reverse' for 40:Fixnum                        
 from (irb):10                                                                 
 from :0 

你不能翻转一个数字，翻转一个数字没有意义，Ruby抛出一条错误信息，它在告诉你数字没有reverse方法。

也许你可以先将该数字转换成字符串：40.to_s.reverse

>> 40.to_s.reverse
=> "04"

数字和字符串不同。你可以在任何object上使用method，一些methods只能用于特定的type上，但是你可以使用Ruby's "to" method在各种类型之间作转换。

to_s converts things to strings.
to_i converts things to integers (numbers.)
to_a converts things to arrays.

Arrays是什么？它们是lists，敲入：[]
>> []
=> []

那是一个空list，lists按顺序存储things，这里有一个list，彩票号码：[12, 47, 35]
>> [12, 47, 35]
=> [12, 47, 35]

找出彩票号码中的最大值：[12, 47, 35].max
>> [12, 47, 35].max
=> 47

总是重复写[12, 47, 35]这么一个大长串比较麻烦，我们将这些彩票号码放入一个’ticket’里吧，像这样：ticket = [12, 47, 35]
>> ticket = [12, 47, 35]
=> [12, 47, 35]

现在敲入ticket：
>> ticket
=> [12, 47, 35]

彩票号码被挤入一个变量ticket中，我们来给彩票号码排个序，怎么做呢：ticket.sort!
>> ticket.sort!
=> [12, 35, 47]

现在你拥有了一个已经排好序的list了，而且变量ticket被改变了。我们来看看第二分钟我们都学到了什么东西：
(1) Errors. If you try to reverse a number or do anything fishy, Ruby will skip the prompt and tell you so.
(2) Arrays are lists for storing things in order.
(3) Variables save a thing and give it a name. You used the equals sign to do this. Like: ticket = [14, 37, 18].

打印一首诗吧
>> print poem
My toast has flown from my hand                                                
And my toast has gone to the moon.                                             
But when I saw it on television,                                               
Planting our flag on Halley's comet,                                           
More still did I want to eat it.                                               
=> nil                           

试试这样一个操作：poem['toast'] = 'honeydew'，之后再print poem看看我们的新诗：
>> poem['toast'] = 'honeydew'                                                  
=> "honeydew"

>> print poem
My honeydew has flown from my hand                                             
And my toast has gone to the moon.                                             
But when I saw it on television,                                               
Planting our flag on Halley's comet,                                           
More still did I want to eat it.                                               
=> nil   

[]意思是"我要找…"，这里我们要在poem中找'toast'并将之替换成'honeydew'，这里有一个问题，如果我们将整首诗翻转会怎样呢：poem.reverse.

>> poem.reverse                                                                
=> "\n.ti tae ot tnaw I did llits eroM\n,temoc s'yellaH no galf ruo gnitnalP\n,n
oisivelet no ti was I nehw tuB\n.noom eht ot enog sah tsaot ym dnA\ndnah ym morf
 nwolf sah wedyenoh yM"

可以肯定的是整首诗都被一个字母一个字母的翻转了。其实我只是想按行翻转，即最后一行变成第一行，第一行变成最后一行，而不是像现在这样翻转，试试poem.to_a.reverse.
>> poem.to_a.reverse                                                           
=> ["More still did I want to eat it.\n", "Planting our flag on Halley's comet,\
n", "But when I saw it on television,\n", "And my toast has gone to the moon.\n"
, "My honeydew has flown from my hand\n"]   

发生什么了？发生两件事：你将poem转换成array了，当Ruby将字符串转换为array时，它以每一行为一个单位，这就是我们得到上面结果的原因，因为array被翻转了。我们再来看一个method吧：print poem.to_a.reverse.join

>> print poem.to_a.reverse.join                                                
More still did I want to eat it.                                               
Planting our flag on Halley's comet,                                           
But when I saw it on television,                                               
And my toast has gone to the moon.                                             
My honeydew has flown from my hand                                             
=> nil  

join方法将已经按行翻转的list重新组合成一个字符串，当然你也可以使用to_s方法。

Review Time：
(1) Exclamations. Methods may have exclamations (and also question marks) in their name. No big deal. Try: poem.include? "my

hand"
(2) Square brackets. Target and find things. Search and replace.
(3) Chaining methods lets you get a lot more done. Break up a poem, reverse it, reassemble it: poem.to_a.reverse.join

OK，如果你准备好继续了，敲入books = {}
>> books = {}                                                                  
=> {}

你已经建立起一个空的Hash表了，现在我们准备在这个Hash中建立一个book rating系统：

:splendid -> a masterpiece.
:quite_good -> enjoyed, sure, yes.
:mediocre -> equal parts great and terrible.
:quite_not_good -> notably bad.
:abyssmal -> steaming wreck.

如果你要rate一本书，你可以像这样做：books["Gravity's Rainbow"] = :splendid，将书目放入[]中，将rating放在等号后面。
>> books["Gravity's Rainbow"] = :splendid                                       
=> :splendid    

继续填充该Hash，这些级别为the ratings are: :splendid, :quite_good, :mediocre, :quite_not_good, and :abyssmal. 它们不是strings，把一个:放在一个单词的前面，你就将得到一个符号，在内存空间占用上，符号要比string少得多. 符号在内存中只存储一次，但是可以多次使用，这点string是做不到的。如果你已经输入了3、4本书了，你可以敲入books.length来得到书的个数。

>> books["Gravity's Rainbow1"] = :quite_good                                    
=> :quite_good                                                                  
                                                                                
>> books["Gravity's Rainbow2"] = :quite_good                                    
=> :quite_good                                                                  
                                                                                
>> books["Gravity's Rainbow3"] = :quite_not_good                                
=> :quite_not_good                                                              
                                                                                
>> books.length                                                                 
=> 4                      

如果你想查找某本书的rating，只需要将书名放入[]之间：
>> books["Gravity's Rainbow"]                                                   
=> :splendid                                                                    

又到总结时间了，目前你学会了：
(1) Hashes. The little dictionary with the curly pages: {}.
(2) Symbols. Tiny, efficient code words with a colon: :splendid.

我们的'寓教于乐'就到此为止了，其实TryRuby后面还有6节内容，因为篇幅太长，这里仅是抛砖引玉，剩下的大家可以自己到TryRuby去感受去学习。