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Date: Fri, 14 Jun 2024 23:49:37 -0400
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Subject: Re: "undefined behavior"?
Newsgroups: comp.lang.c
References: <666a095a$0$952$882e4bbb@reader.netnews.com>
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 <666b0451$0$953$882e4bbb@reader.netnews.com> <v4hu1b$2ve93$3@dont-email.me>
 <666ccccb$0$973$882e4bbb@reader.netnews.com>
 <87r0cz3rx5.fsf@nosuchdomain.example.com>
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From: DFS <nospam@dfs.com>
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On 6/14/2024 9:39 PM, Keith Thompson wrote:
> DFS <nospam@dfs.com> writes:
> [...]
>> During conversion, I got a Python error I don't remember seeing in the past:
>>
>> "TypeError: list indices must be integers or slices, not float"
>>
>> because division returns a float, and some of the array addressing was
>> like this: nums[i/2].
> [...]
> 
> C's "/" operator yields a result with the type of the operands (after
> promotion to a common type).
> 
> Python's "/" operator yields a floating-point result.  For C-style
> integer division, Python uses "//".  (Python 2 is more C-like.)


I was surprised python did that, since every division used in the array 
addressing results in an integer.

After casting i to an int before any array addressing, // works.

Thanks