the most efficient method of adding elements to the list

[alf]

Hi,

Would it be .append()? Does it reallocate te list with each apend?

l=[]
for i in xrange(n):
l.append(i)
Thx, A.

[Girish Sahani]

> Hi,

Would it be .append()? Does it reallocate te list with each apend? Yes it does.
If order of the new element being added doesnt matter you can use append.
If it does, you can use insert().
l=[]
for i in xrange(n):
l.append(i)
Thx, A.
--
http://mail.python.org/mailman/listinfo/python-list

[Erik Max Francis]

alf wrote:

Would it be .append()? Does it reallocate te list with each apend?

l=[]
for i in xrange(n):
l.append(i)

No, it doesn't. It expands the capacity of the list if necessary.

--
Erik Max Francis && ma*@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
It isn't important to come out on top, what matters is to be the one
who comes out alive. -- Bertolt Brecht, 1898-1956

[K.S.Sreeram]

alf wrote:

Would it be .append()? Does it reallocate te list with each apend?

No append does NOT reallocate for every call. Whenever a reallocation
happens, the newsize is proportional to the older size. So you should
essentially get amortized constant time for every append call.

If you want to add a bunch of items in one call.. you should use the
'extend' method.

Regards
Sreeram
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.2.2 (MingW32)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFEhQlLrgn0plK5qqURApHbAKC1A2xYXdgyj9+4a4Nkg7 9+rMdfrwCgi4xP
4VMZi08TTCKblHBxMssZEYA=
=DdkB
-----END PGP SIGNATURE-----

[bruno at modulix]

alf wrote:

Hi,

Would it be .append()? Does it reallocate te list with each apend?

l=[]
for i in xrange(n):
l.append(i)

<dumb>
FWIW, you'd have the same result with:
l = range(n)
</dumb>
More seriously (and in addition to other anwsers): you can also
construct a list in one path:

l = [i for i in xrange(n)]

or if you want operations and conditionals :

l = [trasform(i) for i in xrange(n) if match_some_cond(i)]

HTH
--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'o****@xiludom.gro'.split('@')])"