Ruby 变量赋值

Question

有人可以解释这种行为吗：

a = b = c = 1, 2, 3 
a # => [1, 2, 3]
b # => 1
c # => 1

在赋值a = b = c = 1, 2, 3中，变量a、b和c应该被赋值[1, 2, 3]。有什么想法吗？

Answer 1

你糊涂了

a=b=c=1,2,3

实际上是：

a = (b = c = 1), 2, 3

剩下

c = 1 # => 1 
b = c # => 1 
a = 1,2,3 # => [1, 2, 3]

Answer 2

要执行您所说的操作，您应该按照以下步骤操作：

a,b,c = 1,2,3
    p a #=> 1
    p b #=> 2
    p c #=> 3

Answer 3

Can someone explain why is this happening

@shivam 问题，但添加一些括号可能会更清楚。

a = b = c = 1, 2, 3

解释为：

a = [(b = (c = 1)), 2, 3]

表达式按以下顺序求值：

           c = 1
      b = (     )
a = [(           ), 2, 3]

the variables a, b, and c should be assigned [1, 2, 3]

要获得预期的结果，您可以这样写：

a = b = c = [1, 2, 3]

解释为：

a = (b = (c = [1, 2, 3]))

并按以下顺序评估：

          c = [1, 2, 3]
     b = (             )
a = (                   )

Ruby variable assignment