Message-ID: <XFMail.111009090002.ted.harding@wlandres.net>
Date: 2011-10-09T08:00:02Z
From: (Ted Harding)
Subject: round() and negative digits
In-Reply-To: <4E90EF02.1050403@witthoft.com>
On 09-Oct-11 00:46:58, Carl Witthoft wrote:
>
> On 10/8/11 6:11 PM, (Ted Harding) wrote:
>
>> Carl Witthoft's serendipitous discovery is a nice example
>> of how secrets can be guessed by wondering "what if ... ?".
>> So probably you don;t need to tell the secrets.
>>
>> Taking the "negative digits" to their logical extreme:
>>
>> round(654.321,2)
>> # [1] 654.32
>> round(654.321,1)
>> # [1] 654.3
>> round(654.321,0)
>> # [1] 654
>> round(654.321,-1)
>> # [1] 650
>> round(654.321,-2)
>> # [1] 700
>> round(654.321,-3)
>> # [1] 1000
>> round(654.321,-4)
>> # [1] 0
>>
>> which is what you'd logically expect (but is it what you
>> would intuitively expect?).
>>
> Oh, oh, somebody's going all metaphysical on us.
Nor should one forget the rounding rules (not OS-dependent
in this case, I think ... ?):
round(5000,-4)
# [1] 0
round(15000,-4)
# [1] 20000
Ted.
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Date: 09-Oct-11 Time: 08:59:58
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