ruby - can't modify frozen string (TypeError)

1.在使用ruby的命令行参数的时候, 实际上是引用的赋值方式

 

测试代码, 保存为test.rb:

 

arg = ARGV[ 0 ]

arg.gsub!( /\r\n?/, "\n" )

 

运行test.rb会报错:

 

ruby test.rb string_to_test

test.rb:3:in `gsub!': can't modify frozen string (RuntimeError)

        from test.rb:3:in `<main>'

 

有点不是太明白, ruby为什么要这样做

 

 

2.解决方法

 

arg = ARGV[ 0 ].dup

arg.gsub!( /\r\n?/, "\n" )

  

 

参考: http://stackoverflow.com/questions/2204945/ruby-cant-modify-frozen-string-typeerror