来自网站best-ruby.com
数字字母混合进制
"1az".next
#=> "1ba"
"1aaz".next
#=> "1aba"联想数组
aa = [ %w[Someone 1],
%w[Bla 2]]
p aa.assoc("Someone")
p aa.assoc("Bla")
# Result:
# ["Someone", "1"]
# ["Bla", "2"]
p aa.rassoc("1")
p aa.rassoc("2")
# Result:
# ["Someone", "1"]
# ["Bla", "2"]退出时执行
#Basic use
puts 'script start'
at_exit do
puts 'inside at_exit method for the first time'
end
#anywhere in your code again
at_exit do
puts 'inside at_exit method for the second time'
end
puts "script end"
#Result:
#script start
#script end
#inside at_exit method for the second time
#inside at_exit method for the first time
#Own exception crash logger
at_exit do
if $! # If the program exits due to an exception
puts 'Exiting'
#you can also print log to a file
#you can send notification to another app
end
end
#Logging error anywhere when program exit
(Thread.current[:errors] ||= []) << 'Any error message goes here'
#or
def log_error(error_message)
(Thread.current[:errors] ||= []) << "#{error_message}"
end
#Now, log all the errors
at_exit do
File.open('errors.txt', 'a') do |file|
(Thread.current[:errors] ||= []).each do |error|
file.puts error
end
end
end自动嵌套
deep = Hash.new { |hash,key| hash[key] = Hash.new(&hash.default_proc) }
deep[:a][:b][:c][:d] = 42
p deep
# Result:
# {:a=>{:b=>{:c=>{:d=>42}}}}块能包块
var = :var
object = Object.new
object.define_singleton_method(:show_var_and_block) do |&block|
p [var, block]
end
object.show_var_and_block { :block }
# Result:
# [:var, #<Proc:0x007ffd6c038128@./blocks_can_take_blocks.rb:8>]线程冒泡错误提示
Thread.abort_on_exception = true
Thread.new do
fail 'Ops, we cannot continue'
end
loop do
sleep
end
# Result:
# ./bubbling_up_thread_errors.rb:4:in `block in <main>': Ops, we cannot continue (RuntimeError)范围情景选择
age = rand(1..100)
p age
case age
when -Float::INFINITY..20
p 'You are too young'
when 21..64
p 'You are at the right age'
when 65..Float::INFINITY
p 'You are too old'
end
# Result:
# 55
# "You are at the right age"罗列所有对象
require 'pp'
pp ObjectSpace.count_objects
# Result:
# {:TOTAL=>30163,
# :FREE=>1007,
# :T_OBJECT=>39,
# :T_CLASS=>534,
# :T_MODULE=>24,
# :T_FLOAT=>4,
# :T_STRING=>9290,
# :T_REGEXP=>70,
# :T_ARRAY=>2231,
# :T_HASH=>53,
# :T_STRUCT=>1,
# :T_BIGNUM=>2,
# :T_FILE=>14,
# :T_DATA=>966,
# :T_MATCH=>1,
# :T_COMPLEX=>1,
# :T_NODE=>15896,
# :T_ICLASS=>30}循环
ring = %w[one two three].cycle
p ring.take(5)
# Result:
# ["one", "two", "three", "one", "two"]读出数据
puts DATA.read
__END__
Hey oh!
Hey oh!最简单的数据库
require 'pstore'
db = PStore.new('mydatabase.pstore')
db.transaction do
db['people1'] = 'Someone'
db['money1'] = 400
end
db.transaction do
db['people2'] = 'Someone2'
db['money2'] = 300
end
db.transaction(true) do
p 'People %p' % db['people1']
p 'Money %p' % db['money1']
p "SECOND PERSON"
p 'People %p' % db['people2']
p 'Money %p' % db['money2']
end
# Result:
# "People \"Someone\""
# "Money 400"
# "SECOND PERSON"
# "People \"Someone2\""
# "Money 300"