Comments on: Another ten essential Python tips

By: anon

anon — Sun, 11 Sep 2011 03:48:51 +0000

just came across a link to few free python book. very useful for python beginners
http://cmdlinetips.com/2011/09/free-python-books-online/

By: Another ten essential Python tips | Linux User | Errors & Geeks

Another ten essential Python tips | Linux User | Errors & Geeks — Sat, 20 Feb 2010 08:25:16 +0000

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By: Lawrence D’Oliveiro

Lawrence D’Oliveiro — Fri, 19 Feb 2010 06:58:39 +0000

Removing duplicates: do it in one line using sets, not dictionaries:

>>> l = (1, 2, 2, 3, 4)
>>> l
(1, 2, 2, 3, 4)
>>> type(l)(set(l))
(1, 2, 3, 4)
>>> l = [3, 4, 3, 5, 6]
>>> l
[3, 4, 3, 5, 6]
>>> type(l)(set(l))
[3, 4, 5, 6]

By: Lawrence D’Oliveiro

Lawrence D’Oliveiro — Fri, 19 Feb 2010 06:57:22 +0000

What do you think your “gc” example is achieving? It’s only referencing the functions, not calling them. I think you want empty parentheses “()” after each function name, to indicate you’re calling them.

By: gwb

gwb — Wed, 17 Feb 2010 14:37:11 +0000

nope. didn’t work

By: gwb

gwb — Wed, 17 Feb 2010 14:36:49 +0000

the problem with the white space seems to be a problem of the site’s handling of data. Dunno if it supports pre-formatted tags. Let’s try:

this
is
indented

By: Rick

Rick — Wed, 17 Feb 2010 03:19:45 +0000

Since white space is significant in python, several of the code examples need to be cleaned up.

By: paul

paul — Wed, 17 Feb 2010 00:49:32 +0000

Removing duplicates from lists can be done a lot easier with set. E.g.:

>>> l = [1,2,2,3,4,4,5]
>>> set(l)
set([1, 2, 3, 4, 5])

By: Tom K

Tom K — Tue, 16 Feb 2010 20:55:01 +0000

I think you want to complEment the other collections of tips, not complIment them.

By: gwb

gwb — Tue, 16 Feb 2010 20:18:15 +0000

The example of removing dups from a list can also be done with set semantics:

newlist = list(set(oldlist))

Note that both this approach and the original one will destroy the order of the elements. If you want to preserve order, something like this would do it:

def unique(list_):
s = set()
newl = []
for x in list_:
if x not in s:
new.append(x)
s.add(x)
return newl

You could even be tricksy with something like this:

listset = set()
newlist = list(x for x in oldlist if x not in listset and not listset.add(x))

since set().add() returns None which is boolean False so “not set().add()” will always be true. However, this method involves redundant calls to set().add().