Message 264670 - Python tracker

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Author	Peter.Norvig
Recipients	Peter.Norvig
Date	2016-05-02.20:59:10
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1462222751.06.0.733276334894.issue26913@psf.upfronthosting.co.za>
In-reply-to

Content
mean([True, True, True, False]) should be 0.75, but it returns 0.25. The fix is to change _sum so that when the type is bool, the result should be coerced to int, not bool. Why it is important for statistics.mean to work with bools: It is natural to say something like mean(x > threshold for x in data) and expect to get the percentage of items in data that are above threshold.

mean([True, True, True, False]) should be 0.75, but it returns 0.25.

The fix is to change _sum so that when the type is bool, the result should be coerced to int, not bool.

Why it is important for statistics.mean to work with bools:
It is natural to say something like
    mean(x > threshold for x in data)
and expect to get the percentage of items in data that are above threshold.

History
Date	User	Action	Args
2016-05-02 20:59:11	Peter.Norvig	set	recipients: + Peter.Norvig
2016-05-02 20:59:11	Peter.Norvig	set	messageid: <1462222751.06.0.733276334894.issue26913@psf.upfronthosting.co.za>
2016-05-02 20:59:11	Peter.Norvig	link	issue26913 messages
2016-05-02 20:59:10	Peter.Norvig	create