Hi,
I have the following problem:
I have a list like
e = ['a', 'b', 'e']
and another list like
l = ['A', 'a', 'c', 'D', 'E']
I would like to remove from l all the elements that appear in e
case-insensitive. That is, the result would be
r = ['c', 'D']
What is a *nice* way of doing it?
I have a list like
e = ['a', 'b', 'e']
and another list like
l = ['A', 'a', 'c', 'D', 'E']
I would like to remove from l all the elements that appear in e
case-insensitive. That is, the result would be
r = ['c', 'D']
What is a *nice* way of doing it?
Well, it's usually
That is a nice solution.
But, how about modifying the list in place?
That is, l would become ['c', 'D'].
Thanks a lot,
Ray
Tim Chase wrote:
I have a list like
e = ['a', 'b', 'e']
and another list like
l = ['A', 'a', 'c', 'D', 'E']
I would like to remove from l all the elements that
That is a nice solution.
But, how about modifying the list in place?
That is, l would become ['c', 'D'].
e = ['a', 'b', 'e']
l = ['A', 'a', 'c', 'D', 'E']
s = set(e)
[x for x in l if x.lower() not in s]
['c', 'D']
Well...changing the requirements midstream, eh? ;-)
You can
Rares Vernica wrote:
I have the following problem:
I have a list like
e = ['a', 'b', 'e']
and another list like
l = ['A', 'a', 'c', 'D', 'E']
I would like to remove from l all the elements that appear in e
case-insensitive. That is, the result would be
r = ['c', 'D']
What
Yeah, I ended up doing a similar kind of loop. That is pretty messy.
Is there any other way?
Thanks,
Ray
Tim Chase wrote:
That is a nice solution.
But, how about modifying the list in place?
That is, l would become ['c', 'D'].
e = ['a', 'b', 'e']
l = ['A', 'a', 'c', 'D', 'E']
s =
Fredrik Lundh wrote:
What is a *nice* way of doing it?
r = [i for i in e if i not in l]
and swap l and e, add a few calls to lower, and start using better
variable names in the future.
/F
--
http://mail.python.org/mailman/listinfo/python-list
Yeah, I ended up doing a similar kind of loop. That is pretty messy.
Is there any other way?
I've already provided 2 (or 3 depending on how one counts)
solutions, each of which solve an interpretation of your original
problem, neither of which involve more than 3 lines of fairly
clean
from sets import Set as set # Python 2.3
b = list( set([i.upper() for i in b) - set([i.upper() for i in a] ) )
Rares Vernica wrote:
Yeah, I ended up doing a similar kind of loop. That is pretty messy.
Is there any other way?
Thanks,
Ray
Tim Chase wrote:
That is a nice solution.
from sets import Set as set # Python 2.3
b = list( set([i.upper() for i in b) - set([i.upper() for i in a] ) )
Just a caveat...this can change the order of items in the results
as sets (and their differences) are inherently unordered data
structures. If order of the items in the list
Scratch that. b becomes all upper...
John Henry wrote:
from sets import Set as set # Python 2.3
b = list( set([i.upper() for i in b) - set([i.upper() for i in a] ) )
Rares Vernica wrote:
Yeah, I ended up doing a similar kind of loop. That is pretty messy.
Is there any other way?
Sorry for not being clear from the beginning and for not using clear
variable names.
Problem context:
import os
dirs_exclude = set(('a', 'b', 'e'))
for root, dirs, files in os.walk('python/Lib/email'):
# Task:
# delete from dirs the directory names from dirs_exclude
#
The curve ball is the case insensitivity otherwise it's a
straightforward set operation.
I wonder if it's possible to sub-class set and make the item
comparision case insensitive.
Anybody knows how to do that?
Tim Chase wrote:
Yeah, I ended up doing a similar kind of loop. That is pretty
The solution so far is:
for i in xrange(len(dirs), 0, -1):
if dirs[i-1].lower() in dirs_exclude:
del dirs[i-1]
This won't affect much, but uses better style I think.
Change:
for i in xrange(len(dirs),0,-1):
To:
for i in reversed(xrange(len(dirs))):
and then just use 'i' instead
On 2006-11-17, Rares Vernica [EMAIL PROTECTED] wrote:
Sorry for not being clear from the beginning and for not using
clear variable names.
Problem context:
import os
dirs_exclude = set(('a', 'b', 'e'))
for root, dirs, files in os.walk('python/Lib/email'):
# Task:
# delete from
OK, if you don't care the resulting order, do it like:
class Convert2Dict:
def __init__(self, data):
self._data={}
for x in data:
self._data[x.upper()]=x
def get(self, key):
return self._data[key.upper()]
a = [a, B]
b = [c, a, A, D, b]
b_dict =
On Fri, 17 Nov 2006 12:00:46 -0800, Rares Vernica wrote:
Problem context:
import os
dirs_exclude = set(('a', 'b', 'e'))
for root, dirs, files in os.walk('python/Lib/email'):
# Task:
# delete from dirs the directory names from dirs_exclude
# case-insensitive
The solution
The problem with skipping over them is that walk would still walk them
and their content. If they have a lot of other dirs and files inside
then this might end up being time consuming.
Thanks,
Ray
Neil Cerutti wrote:
On 2006-11-17, Rares Vernica [EMAIL PROTECTED] wrote:
Sorry for not being
This solution I think is pretty nice:
source[:] = [x for x in source if x.lower() not in target]
Thanks a lot for all the answers,
Ray
Steven D'Aprano wrote:
On Fri, 17 Nov 2006 12:00:46 -0800, Rares Vernica wrote:
Problem context:
import os
dirs_exclude = set(('a', 'b', 'e'))
for root,
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