Re: [Tutor] how to permanently add a module path
"Christopher Arndt" <[EMAIL PROTECTED]> wrote > Linux: > > Depends on your distribution: It depends even more on the shell you use. In csh or tcsh the file to modify is .cshrc > - Standard way would be to edit ~/.bash_profile and add e.g. I prefer to modify environment variables in .profile. That way they are visible in bash, sh, ksh, ash which all read .profile, whereas only bash reads .bash_profile. > # entries are separated by colons ':' > PYTHONPATH=$HOME/lib/python:/where/my/other/python/modules/live > export PYTHONPATH I usually put $PYTHONPATH in front too in case there is a site wide version defined already. HTH, -- Alan Gauld Author of the Learn to Program web site http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Lists on the fly?
"Carlos" <[EMAIL PROTECTED]> wrote > I am wondering if it is possible to create lists on the fly. In general you can use a list comprehension to do that. > This is only so you can have an idea: > > for i in range(5): >'list_%i' % (i) = [] >>> mylists = [ [] for n in range(5)] creats a list of 5 empty lists. You can then poulate the sublists using normal indexing: >>> mylists[0].append(5) >>> print mylists[0][0] 5 You can find more on List Comprehensions in the Functional Programming topic of my web tutor. HTH, -- Alan Gauld Author of the Learn to Program web site http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Lists on the fly?
"Luke Paireepinart" <[EMAIL PROTECTED]> wrote >>> 'list_%i' % (i) = [] >>> > Note, though this is pretty arbitrary :) and only saves you 2 > characters... > You don't need to create a tuple if you're only packing in one > value. > >>> i = 1 > >>> 'list_%i' % i And that works for multiple values provided they are unambiguous. "%d,%d,%d" % 1,2,3 You need the parens if the substitution values are more complex and include operators: "%d,%d,%d" % 1, 2, 1+2 Will give an error (adding int to string) you need the parens here: "%d,%d,%d" % (1, 2, 1+2) HTH, Alan G ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] [tutor] sort a list
Hi List, I have a list like this x=[7,4,2,6] and print x.sort() gives to me None ! : >> x=[7,4,2,6] >> print x.sort() None ... but >> x=[7,4,2,6] >> x.sort() >> print x [2, 4, 6, 7] so, why list.sort() returns None? is this normal ? (the python is "Python 2.4.3 (#69, Mar 29 2006, 17:35:34) [MSC v.1310 32 bit (Intel)] on win32") E. - Започва новото голямо приключение! Ерагон: от 15 декември в кината. http://reklama.mail.bg/eragon/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] [tutor] sort a list
[EMAIL PROTECTED] wrote: > Hi List, > > I have a list like this x=[7,4,2,6] > and print x.sort() > gives to me None ! : > > >>> x=[7,4,2,6] >>> print x.sort() >>> > None > > ... but > > >>> x=[7,4,2,6] >>> x.sort() >>> print x >>> > [2, 4, 6, 7] > > so, why list.sort() returns None? is this normal ? > No, this is not normal. When the planets are aligned perfectly (which is very rare, thankfully), it creates magnetic interference that messes with Python interpreters in RAM and causes the list.sort method to return None. It's still being investigated. It just so happens that we had a momentary planet alignment earlier this week, which should explain the problems you've been having. Seriously, though, see http://www.python.org/infogami-faq/general/why-doesn-t-list-sort-return-the-sorted-list/ for an explanation. Basically, as we can see here > (the python is "Python 2.4.3 (#69, Mar 29 2006, 17:35:34) > [MSC v.1310 32 bit (Intel)] on win32") > you're using Python 2.4, so you can just do sorted(x) and it will return the sorted list. It also might be a good idea to read the rest of that FAQ. HTH, -Luke ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Lists on the fly?
Hi,
First of all, thanks for your help.
This is how this ended up:
Elements = [
{'Name': 'Access', 'Parent': 'Plot',
'Level': 1.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0},
{'Name': 'Circulation_01', 'Parent':
'Access', 'Level': 1.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0},
{'Name': 'Circulation_02', 'Parent':
'Access', 'Level': 2.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0},
{'Name': 'Circulation_03', 'Parent':
'Access', 'Level': 3.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0},
{'Name': 'Int_Circ_01', 'Parent':
'Circulation_01', 'Level': 1.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0},
{'Name': 'Int_Circ_02', 'Parent':
'Circulation_01', 'Level': 1.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0},
{'Name': 'Int_Circ_03', 'Parent':
'Circulation_02', 'Level': 2.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0},
{'Name': 'Int_Circ_04', 'Parent':
'Circulation_02', 'Level': 2.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0},
{'Name': 'Int_Circ_05', 'Parent':
'Circulation_03', 'Level': 3.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0},
{'Name': 'Int_Circ_06', 'Parent':
'Circulation_03', 'Level': 3.0, 'Height': 3.0, 'Width': 3.0, 'Depth': 3.0}
]
# Get Levels List
for Element in Elements:
Lev_List['Level_%i' % (Element['Level'])] = []
# Append Element to corresponding Level
for Element in Elements:
Lev_List['Level_%i' % (Element['Level'])].append(Element['Name'])
print Lev_List
And this is the result:
Lev_List = {
'Level_1': ['Access', 'Circulation_01',
'Int_Circ_01', 'Int_Circ_02'],
'Level_2': ['Circulation_02', 'Int_Circ_03',
'Int_Circ_04'],
'Level_3': ['Circulation_03', 'Int_Circ_05',
'Int_Circ_06']
}
It works fine, as far as I can tell. I mean, no matter how many 'Levels'
it will allways get them right (levels so far are only integers).
Probably the first loop is a little redundant, but performance is not
one of my concerns now, but in the future the project will not be
composed by a handful of spaces, probably by hundreds or more.
Regards,
Carlos
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Re: [Tutor] Lists on the fly?
[snip]
> # Get Levels List
> for Element in Elements:
> Lev_List['Level_%i' % (Element['Level'])] = []
>
> # Append Element to corresponding Level
> for Element in Elements:
> Lev_List['Level_%i' % (Element['Level'])].append(Element['Name'])
[snip snip]
> Probably the first loop is a little redundant, but performance is not
> one of my concerns now, but in the future the project will not be
> composed by a handful of spaces, probably by hundreds or more.
>
I think a better way to do this is to check if 'Level_%i' is in your
dictionary already.
so the loop becomes
Lev_List = {}
for Element in Elements:
keystr = 'Level_%i' % Element['Level']
if not Lev_List.has_key(keystr):
Lev_List[keystr] = []
Lev_List[keystr].append(Element['Name'])
And of course you can go the EAFP (easier to ask forgiveness than
permission)
route and use a try/accept block
Lev_List = {}
for Element in Elements:
keystr = 'Level_%i' % Element['Level']
try:
Lev_List[keystr].append(Element['Name'])
except KeyError:
Lev_List[keystr] = [Element['Name']]
I suspect the try/accept would be the fastest,
but you'd have to timeit to be sure, of course.
HTH,
-Luke
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Re: [Tutor] Lists on the fly?
Luke Paireepinart wrote:
> I think a better way to do this is to check if 'Level_%i' is in your
> dictionary already.
> so the loop becomes
>
> Lev_List = {}
> for Element in Elements:
> keystr = 'Level_%i' % Element['Level']
> if not Lev_List.has_key(keystr):
>Lev_List[keystr] = []
> Lev_List[keystr].append(Element['Name'])
I am a fan of dict.setdefault() which has this logic built in:
Lev_List = {}
for Element in Elements:
keystr = 'Level_%i' % Element['Level']
Lev_List.setdefault(keystr, []).append(Element['Name'])
Also there is no need to create a string for the key, Element['Level']
is a fine key:
Lev_List = {}
for Element in Elements:
Lev_List.setdefault(Element['Level'], []).append(Element['Name'])
Kent
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Re: [Tutor] Lists on the fly?
Kent Johnson wrote:
> Luke Paireepinart wrote:
>
>> I think a better way to do this is to check if 'Level_%i' is in your
>> dictionary already.
> I am a fan of dict.setdefault() which has this logic built in:
> Lev_List = {}
> for Element in Elements:
> keystr = 'Level_%i' % Element['Level']
> Lev_List.setdefault(keystr, []).append(Element['Name'])
>
> Also there is no need to create a string for the key, Element['Level']
> is a fine key:
>
You're absolutely right, Kent.
I just created a variable for it because I referred to it 3 times, and
didn't want to write out the string over and over.
The only reason I used 'Level_%i' instead of just Element['Level'] was
because he had that in the original program.
> Lev_List = {}
> for Element in Elements:
> Lev_List.setdefault(Element['Level'], []).append(Element['Name'])
>
Really cool.
I'm a fan now, too :)
Thanks for this.
-Luke
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Re: [Tutor] MVC/MVP examples of how to implement it
Don Taylor пишет: > Basil Shubin wrote: >> Hi friends! >> >> I have read articles about MVC/MVP, but still can't get a clue to how >> implement it in really working application :-( Because I better >> understand with ready to use examples, can you provide link to free >> python+GUI application which implements MVC/MVP design? >> > Here is another example of MVP in Python/wxPython. > > http://wiki.wxpython.org/index.cgi/ModelViewPresenter Thanks, now I almost implement what I want :-) BTW current design of my app is much better with MVP than with my own solution. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
