ruby - 打印 string.length 时出错

Question

为什么我不能打印常量字符串的长度？ 这是我的代码:

#!/usr/bin/ruby
Name = "Edgar Wallace"
name = "123456"

puts "Hello, my name is " + Name
puts "My name has " + Name.to_s.length + " characters."

我已经读过“How do I determine the length of a Fixnum in Ruby?”，但不幸的是它对我没有帮助。

尝试后，报错:

./hello.rb:7:in `+': can't convert Fixnum into String (TypeError)
          from ./hello.rb:7:in `<main>'

Answer 1

您不能连接到带有 Fixnum 的字符串:

>> "A" + 1
TypeError: can't convert Fixnum into String
    from (irb):1:in `+'
    from (irb):1
    from /usr/bin/irb:12:in `<main>'
>> "A" + 1.to_s
=> "A1"

而且，您不需要 Name.to_s，因为 Name 已经是一个 String 对象。只需 Name 就足够了。

将 Fixnum (length) 转换为字符串:

puts "My name has " + Name.length.to_s + " characters."

或者，作为替代:

puts "My name has #{Name.length} characters."