字符串在Ruby中可变吗? [英] Are strings mutable in Ruby?

问题描述

字符串在Ruby中可变吗?根据文档做

Are Strings mutable in Ruby? According to the documentation doing

str = "hello"
str = str + " world"

创建一个值为"hello world"的新字符串对象，但是当我们这样做

creates a new string object with the value "hello world" but when we do

str = "hello"
str << " world"

它没有提到它会创建一个新对象，所以它会突变str对象，该对象现在将具有值"hello world"?

It does not mention that it creates a new object, so does it mutate the str object, which will now have the value "hello world"?

推荐答案

是的，<<对同一个对象进行了变异，并且+创建了一个新对象.演示:

Yes, << mutates the same object, and + creates a new one. Demonstration:

irb(main):011:0> str = "hello"
=> "hello"
irb(main):012:0> str.object_id
=> 22269036
irb(main):013:0> str << " world"
=> "hello world"
irb(main):014:0> str.object_id
=> 22269036
irb(main):015:0> str = str + " world"
=> "hello world world"
irb(main):016:0> str.object_id
=> 21462360
irb(main):017:0>

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