很喜欢http://www.rubyinside.com这个网站，里面记载了一些Ruby相关的新闻，以及技术相关的，这里爬几个可能会用到的Ruby Trick.
1. 分解枚举
a = %w{a b}
b = %w{c d}
[a + b] # => [["a", "b", "c", "d"]]
[*a + b] # => ["a", "b", "c", "d"]
a = { :name => "Fred", :age => 93 }
[a] # => [{:name => "Fred", :age =>93}]
[*a] # => [[:name, "Fred"], [:age, 93]]
a = %w{a b c d e f g h}
b = [0, 5, 6]
a.values_at(*b).inspect # => ["a", "f", "g"]
2. 不用String 或是 Symbol做hash的键
does = is = { true => 'Yes', false => 'No' }
does[10 == 50] # => "No"
is[10 > 5] # => "Yes"
3.快速赋值
a, b, c, d = 1, 2, 3, 4
def my_method(*args)
a, b, c, d = args
end
def initialize(args)
args.keys.each { |name| instance_variable_set "@" + name.to_s, args[name] }
end
4. 使用Range
# if x > 1000 && x < 2000
year = 1972
puts case year
when 1970..1979: "Seventies"
when 1980..1989: "Eighties"
when 1990..1999: "Nineties"
end
5. DRY很彻底
%w{rubygems daemons eventmachine}.each { |x| require x }
6. 使用三目运算符(有一天我居然听说一个我的同事工作了六七年，说没用用过这个操作符，天啊，什么世道？什么公司敢用这样的程序员？ 和这样的工作，很危险)
def is_odd(x)
# Wayyyy too long..
if x % 2 == 0
return false
else
return true
end
end
=>
def is_odd(x)
x % 2 == 0 ? false : true
end
==》
def is_odd(x)
# Use the logical results provided to you by Ruby already..
x % 2 != 0
end
7. 写程序要捕捉异常
def do_division_by_zero
5 / 0
end
begin
do_division_by_zero
rescue => exception
puts exception.backtrace
end
8. 确保有东西可迭代
items = "hello"
[*items].each do |item|
# ...
end
9 捕获异常不一定非要有begin
def x
begin
# ...
rescue
# ...
end
end
=>
def x
# ...
rescue
# ...
end
10. 块注释
puts "x"
=begin
this is a block comment
You can put anything you like here!
puts "y"
=end
puts "z"
11 rescue to the rescue
h = { :age => 10 }
h[:name].downcase # ERROR
h[:name].downcase rescue "No name" # => "No name"