尝试将字符串传递给is_tut时,我一直收到“no block given”错误？方法.我是
Ruby的新手,不知道我做错了什么.任何和所有的帮助将不胜感激.
class Tut
@@consonants = ["b","c","d","f","g","h","j","k","l","m","n","p","q","r","s","t","v","w","x","y","z"]
def is_tut? string
if string =~ /^(([b-df-hj-np-z]ut)|([aeIoU\s])|[[:punct:]])+$/i
yield
else
false
end
end
def self.to_tut string
string.each_char do |c|
c += "ut" if @@consonants.find { |i| i == c.downcase }
yield c
end
end
def self.to_english string
array = string.split //
array.each do |c|
if @@consonants.find { |i| i == c.downcase }
array.shift
array.shift
end
yield c
end
end
end
#Tut.to_tut( "Wow! Look at this get converted to Tut!" ) { |c| print c }
# should output : Wutowut! Lutookut atut tuthutisut gutetut cutonutvuteruttutedut tuto Tututut!
puts
puts
tut = Tut.to_tut( "Wow! Look at this get converted to Tut!" )
puts "from return: #{tut}"
puts
#Tut.to_tut( "Wutowut! Lutookut atut tuthutisut gutetut cutonutvuteruttutedut tuto Tututut!" ) { |c| print c }
# should outout : Wutowut! Lutookut atut tuthutisut gutetut cutonutvuteruttutedut tuto Tututut!
puts
puts
#tut = Tut.to_tut( "Wutowut! Lutookut atut tuthutisut gutetut cutonutvuteruttutedut tuto Tututut!" )
#puts "from return: #{tut}"
puts
#tut_string = ""
#Tut.to_tut( "I'm in tut but I want to be in english." ) { |c| tut_string += c }
#puts tut_string
# should output : I'mut inut tututut bututut I wutanuttut tuto bute inut enutgutlutisuthut.
puts
#Tut.to_english( tut_string ) { |c| print c }
# should output : I'm in tut but I want to be in english.
解决方法
如果在方法定义中有收益,则意味着在使用时必须强制传递一个块(除非包含它的部分不是根据条件执行等). (您可能已经知道了,但是如果您不知道：一个块被描述为{…}或者…结束)并且yield将引用该块.
如果你想要一个块可选,那么一种方法是将&变量名前的符号.
def method(argument,&block_argument)
if block_argument # block is given
block_argument.call(argument_for_block) # use call to execute the block
else # the value of block_argument becomes nil if you didn't give a block
# block was not given
end
end
这将允许可选块.或者,正如Squeegy所建议的,
def method(argument)
if block_given? # block is given
yield(argument_for_block) # no need to use call to execute the block
else
# block was not given
end
end
也会工作.