Message 327888 - Python tracker

Message327888

Author	steven.daprano
Recipients	cykerway, steven.daprano, tim.peters
Date	2018-10-17.10:34:16
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1539772456.61.0.788709270274.issue35010@psf.upfronthosting.co.za>
In-reply-to

Content
Since sort is guaranteed to be stable, can't you sort in two runs? py> values = ['bc', 'da', 'ba', 'abx', 'ac', 'ce', 'dc', 'ca', 'aby'] py> values.sort(key=itemgetter(1), reverse=True) py> values.sort(key=itemgetter(0)) py> values ['ac', 'abx', 'aby', 'bc', 'ba', 'ce', 'ca', 'dc', 'da'] Its not as efficient as doing a single sort, but its easier to understand than a complex API to specify each item's sort direction individually, and therefore probably less likely to mess it up and get it wrong.

Content

Since sort is guaranteed to be stable, can't you sort in two runs?


py> values = ['bc', 'da', 'ba', 'abx', 'ac', 'ce', 'dc', 'ca', 'aby']
py> values.sort(key=itemgetter(1), reverse=True)
py> values.sort(key=itemgetter(0))
py> values
['ac', 'abx', 'aby', 'bc', 'ba', 'ce', 'ca', 'dc', 'da']


Its not as efficient as doing a single sort, but its easier to understand than a complex API to specify each item's sort direction individually, and therefore probably less likely to mess it up and get it wrong.

History
Date	User	Action	Args
2018-10-17 10:34:16	steven.daprano	set	recipients: + steven.daprano, tim.peters, cykerway
2018-10-17 10:34:16	steven.daprano	set	messageid: <1539772456.61.0.788709270274.issue35010@psf.upfronthosting.co.za>
2018-10-17 10:34:16	steven.daprano	link	issue35010 messages
2018-10-17 10:34:16	steven.daprano	create