"TypeError: no implicit conversion of Symbol into Integer" that is raised when I run `"abc"[:symbol]` is a bit confusing

ruby-talk
1

Hi,
When I debug Ruby code, it's confusing for me to debug the error that appears in Case 2 below becauseI think the "no implicit conversion of Symbol into Integer" is not intuitive in this situation.
I want to know how this behavior was implemented. Could you tell me the reason or the issue related to this behavior?I could not find it as far as I searched on https://bugs.ruby-lang.org/issues.
```# Case 1'abc'[0]
# => "a"
# Case 2'abc'[:something]
# TypeError: no implicit conversion of Symbol into Integer
# Case 3'abc'['something']
# => nil```
Thanks,
Shinohara

2

Hi Shinohara,

This is because the method `` on the String class does not define
behavior when a symbol is passed.
Use of "string" is processed by a method called `String(arg)`. It can
take an int, a range, or a string.

I think the authors of Ruby's core classes didn't think converting the
symbol to a string made sense.
I tend to agree.

Hope this helps.

Andy

<Class: String (Ruby 2.6);

ยทยทยท

On Thu, Jan 30, 2020 at 10:24 AM Shinohara Teruki <ts_3156@yahoo.co.jp> wrote:

Hi,

When I debug Ruby code, it's confusing for me to debug the error that
appears in Case 2 below because
I think the "no implicit conversion of Symbol into Integer" is not
intuitive in this situation.

I want to know how this behavior was implemented. Could you tell me the
reason or the issue related to this behavior?
I could not find it as far as I searched on
Issues - Ruby Issue Tracking System.

# Case 1
'abc'[0]
# => "a"

# Case 2
'abc'[:something]
# TypeError: no implicit conversion of Symbol into Integer

# Case 3
'abc'['something']
# => nil

Thanks,

Shinohara

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