Tutorial, 5.6 Looping Techniques, sorted() example

[mirwi]

BPO	39705
Nosy	@rhettinger, @ericvsmith, @rahul-kumi
PRs	bpo-39705 : sorted() tutorial example under looping techniques improved #18999

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/rhettinger'
closed_at = <Date 2020-05-18.01:32:59.686>
created_at = <Date 2020-02-21.09:24:31.422>
labels = ['type-feature', '3.9', 'docs']
title = 'Tutorial, 5.6 Looping Techniques, sorted() example'
updated_at = <Date 2020-05-18.01:32:59.685>
user = 'https://bugs.python.org/mirwi'

bugs.python.org fields:

activity = <Date 2020-05-18.01:32:59.685>
actor = 'rhettinger'
assignee = 'rhettinger'
closed = True
closed_date = <Date 2020-05-18.01:32:59.686>
closer = 'rhettinger'
components = ['Documentation']
creation = <Date 2020-02-21.09:24:31.422>
creator = 'mirwi'
dependencies = []
files = []
hgrepos = []
issue_num = 39705
keywords = ['patch']
message_count = 6.0
messages = ['362395', '362398', '362415', '362422', '362650', '369158']
nosy_count = 5.0
nosy_names = ['rhettinger', 'eric.smith', 'docs@python', 'mirwi', 'rahul-kumi']
pr_nums = ['18999']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue39705'
versions = ['Python 3.9']

[mirwi]

>>> basket = ['apple', 'orange', 'apple', 'pear', 'orange', 'banana']
>>> for f in sorted(set(basket)):
...     print(f)
...
apple
banana
orange
pear

Shouldn't 'apple' appear two times as basket is a list that allows duplicates, not a set?

I'm just doing my first steps into Python and may be mislead. In that case, sorry for the fuzz.

[ericvsmith]

The code is converting to a set first, then calls sorted() on that set. So "apple" is removed when the set is created.

I'm not sure the example should throw in creating a set while it's talking about sorting.

[rhettinger]

I prefer to keep the example as-is. It is an idiomatic way to loop over sets. The introductory text can be modified to explain that sets eliminate duplicates, that sets are ordered, and that sorted() puts them back in a deterministic order.