Feature Requests item #1548178, was opened at 2006-08-28 13:47
Message generated for change (Comment added) made by josiahcarlson
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=355470&aid=1548178&group_id=5470
Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: Python Interpreter Core
Group: None
Status: Open
Resolution: None
Priority: 4
Submitted By: kovan (kovan)
Assigned to: Nobody/Anonymous (nobody)
Summary: Add 'find' method to sequence types
Initial Comment:
In the benefit of Python's readability and simplicity,
a 'find' method could be added to sequence types, that
would return the first item in the list that matches
some criteria.
For example, it's a common practice to use lists of
(key,value) pairs instead of dictionaries when the
sequence must be ordered.
To find an element maching a key in such cases, I
frequently find myself writing (IMHO) too much code for
such a straightforward operation. AFAIK currently there
are two easy ways to do this (shouln't be one, and only
one?):
for item in items:
if item.attribute == key:
foundItem = item
break
else: foundItem = None
OR
foundItems = [item for item in items if item.key == value]
if foundItems:
foundItem = foundItem[0]
IMO, in none of the cases the code is as clear and,
specially, as short, as it should be.
With the find method, the same code would be:
item = items.find(lambda x: x.key == value)
----------------------------------------------------------------------
Comment By: Josiah Carlson (josiahcarlson)
Date: 2006-09-03 12:07
Message:
Logged In: YES
user_id=341410
Lists have an .index(obj[, start[, stop]]) method that tells
you the index of the first object that matches obj, raising
an exception otherwise.
Generally speaking, you can get better performance for
repeated searches by...
dct = {}
for i,(k,v) in enumerate(lst):
dct.setdefault(k, []).append(i)
Then to find the first index...
dct.get(k, [None])[0]
Suggested close.
----------------------------------------------------------------------
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=355470&aid=1548178&group_id=5470
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
