###7.Lambdas and Blocks ####7.1 Lambdas in Ruby
a lambda is just a function peculiarly(特别的) without a name
lambda 就是个匿名函数 lambdas in ruby are also objects
the last expression of a lambda is its return value
say = lambda { "To Be Or Not To Be" }
puts say.call #To Be Or Not To Be
lambda 可以接收参数
say = lambda do |str|
if str == "HaHaHa"
return str
else
return "No Arguments"
end
end
puts say.call("HaHaHa") #HaHaHa
say = lambda do |str=nil|
if str
return str
else
return "No Arguments"
end
end
puts say.call() #No Arguments
puts say.call("Ha") #Ha
####7.2 Blocks in Ruby
The simplest explanation for a block is that it is a piece of code that can't be stored in a variable and isn't an object.
def add(number)
yield(number)
end
add(2) {|num| num+1} #3
带block参数
def add(num, &block)
if block
yield(num)
else
num * 3
end
end
add(2) #6
add(2) {|num| num + 1 } #3
