无法在`[]`中将字符串更改为int [英] Can't change Strings into int in `[]`

问题描述

在 ruby​​ 中，我尝试在运算符 '[]' 中将 String 转换为 Int，但失败了.这是代码(我的输入是 14 45):

In ruby, I try to convert a String to Int in operator '[]' But failed. Here is the code (my input is 14 45):

STDIN.gets.split(/\s+/).each do |str|
    book = tags[str.to_i]     # book is just a new variable.  tags is an array 
end

ruby​​ 将因错误而停止:在'[]'中:没有将字符串隐式转换为整数(TypeError)

the ruby will stop with an error: in '[]': no implicit conversion of String into Integer (TypeError)

所以我将我的代码更改为如下(这个效果很好.):

So I change my code to follows(this one works well.):

STDIN.gets.split(/\s+/).each do |str|
  number = str.to_i     # for converting
  book = tags[number]
end

这个效果很好.但我必须再添加一行进行转换.有没有避免那条线的好方法?我的 ruby​​ 版本是: $: ruby​​ --version ==>ruby 2.0.0p0 (2013-02-24 修订版39474) [i686-linux]

This one works well. But I must add one more line for converting. Is there a good way for avoiding that line? my version of ruby is: $: ruby --version ==> ruby 2.0.0p0 (2013-02-24 revision39474) [i686-linux]

大家好，请让我知道您为什么仍要关闭此主题.谢谢.

Hi Guys, Please let me KNOW why you still want to close this topic. THANKS.

推荐答案

当您将 String 作为索引传递时，您收到的错误消息肯定会永远发生到 Array#[].因此，您可能没有向我们展示您实际运行的源代码.考虑:

The error message you are getting will definitely only ever occur when you pass a String as an index to Array#[]. So you are probably not showing us the source that you are actually running. Consider:

a = [1,2,3]
str = 'string'

str.to_i
#=> 0
a[str.to_i]
#=> 1

number = str.to_i
#=> 0
a[number]
#=> 1

a['string']
# TypeError: no implicit conversion of String into Integer

顺便说一下，您问题中的错误消息特定于 Ruby 2.0.0:

By the way, the error message in your question is specific to Ruby 2.0.0:

RUBY_VERSION
#=> "2.0.0"

a = [1,2,3]
a['string']
# TypeError: no implicit conversion of String into Integer

而在 Ruby 1.9.3-p392 中，您将收到此错误消息:

Whereas in Ruby 1.9.3-p392 you will get this error message:

RUBY_VERSION
#=> "1.9.3"

a = [1,2,3]
a['string']
# TypeError: can't convert String into Integer

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