David A Black( The Well Grounded Rubyist ,第6章)介绍了以下代码:
def block_local_parameter
x = 100
[1,2,3].each do |x|
puts "Parameter x is #{x}"
x += 10
puts "Reassigned to x in block; it is now #{x}"
end
puts "The value of outer x is now #{x}"
end
block_local_parameter
根据本书的预期输出(Ruby 1.9.1):
Parameter x is 1 Reassigned to x in block; it's now 11 Parameter x is 2 Reassigned to x in block; it's now 12 Parameter x is 3 Reassigned to x in block; it's now 13 Outer x is still 100
我的输出(Ruby 1.8.7):
这本书错了吗?或者,我错过了什么?Parameter x is 1 Reassigned to x in block; it's now 11 Parameter x is 2 Reassigned to x in block; it's now 12 Parameter x is 3 Reassigned to x in block; it's now 13 Outer x is still 13
答案 0 :(得分:8)
您所看到的是Ruby 1.8.x的行为。块的可变范围在1.9中引入,切换到1.9.x,您将得到与书中相同的结果。