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add the method index to collections.deque #54268
Description
| BPO | 10059 |
|---|---|
| Nosy | @rhettinger, @ned-deily |
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 2010-10-10.10:57:31.356>
created_at = <Date 2010-10-10.00:23:45.859>
labels = ['extension-modules', 'type-feature']
title = 'add the method `index` to collections.deque'
updated_at = <Date 2010-10-10.10:57:31.355>
user = 'https://bugs.python.org/SimonLiedtke'bugs.python.org fields:
activity = <Date 2010-10-10.10:57:31.355>
actor = 'Simon.Liedtke'
assignee = 'rhettinger'
closed = True
closed_date = <Date 2010-10-10.10:57:31.356>
closer = 'Simon.Liedtke'
components = ['Extension Modules']
creation = <Date 2010-10-10.00:23:45.859>
creator = 'Simon.Liedtke'
dependencies = []
files = []
hgrepos = []
issue_num = 10059
keywords = []
message_count = 5.0
messages = ['118296', '118297', '118304', '118305', '118333']
nosy_count = 4.0
nosy_names = ['rhettinger', 'ned.deily', 'stutzbach', 'Simon.Liedtke']
pr_nums = []
priority = 'low'
resolution = 'rejected'
stage = None
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue10059'
versions = ['Python 3.2']
Activity
SimonLiedtke commentedon Oct 10, 2010
I'd like to have the method
indexnot only for list, but also for collections.deque.Here is my attempt: http://bitbucket.org/derdon/hodgepodge/src/tip/extended_deque.py
I'm looking forward to see this method implemented in the stdlib!
ned-deily commentedon Oct 10, 2010
Since you are requesting adding a method to an existing data type, you should probably raise this issue first on the python-ideas mailing list and be prepared to justify use cases for it.
http://mail.python.org/mailman/listinfo/python-ideas
rhettinger commentedon Oct 10, 2010
The absence of index() from collections deque wasn't an oversight. Deques are not really about indexed access, they are about appending and popping from the ends. I'm curious about your use case and whether it is a good match for this data structure.
stutzbach commentedon Oct 10, 2010
Hello Simon,
Accessing an arbitrary element of a deque takes O(n) time, making your .index implementation O(n**2).
If you describe the kinds of operations that you need to perform efficiently, we may be able to suggest a better data structure for you to use.
SimonLiedtke commentedon Oct 10, 2010
I see that adding this method to a deque is useless. A list is better for this kind of operation. I just wrote it for fun and realized that it was implemented rather slow.