Hi,
after using Perl for some years for simple scripting tasks, one of my programs
reached a size where an OO design is appropriate. So I rewrote the program
using OO techniques in Perl. Because I am not entirely satisfied with the
implementation, I decided port the program to Python.
The firs
Hi,
Jan Eden wrote on 07.08.2005:
>So how can I add the values of all the paramaters to my class
>instance in one step?
>
apologies for replying to my own post: I just discovered the **args formal
parameter.
Thanks,
Jan
--
I was gratified to be able to answer promptly, and I did.
Hi Kent,
Kent Johnson wrote on 07.08.2005:
>>So how can I add the values of all the paramaters to my class
>>instance in one step?
>
>There was recently a long discussion of this on comp.lang.python.
>http://groups.google.com/group/comp.lang.python/browse_frm/thread/
>7346ad00a14e821a/9dc993d2954
Jan Eden wrote on 07.08.2005:
>But the assignment in the for loop obviously does not work with
>instance attributes. I will have to read up some more about instance
>attributes.
Ok... so this works:
class NewClass:
def __init__(self, **parameters):
self.data = {}
Hi Kent, hi Alan,
Alan G wrote on 07.08.2005:
>> page = Show(type=type, id=id)
>>
>> class Show:
>> def __init__(self, type, id):
>> self.id = id
>> ...
>>return self
>
>First a couple of comments.
>You don't need to return self from __init__.
>You can only instantiate Show *a
Hi,
in Perl's DBI, I used fetchrow_hashref() to receive a database row as a
dictionary, with the field names being the dictionary keys.
MySQLdb's fetchone() returns a tuple Unfortunately, I have a dictionary of SQL
queries which return rows of different lengths (read: with a varying number of
Kent Johnson wrote on 08.08.2005:
>Jan Eden wrote:
>>The documentation for MySQLdb says that fetchoneDict() is
>>deprecated and the usage of fetchone() is suggested.
>
>You could just use fetchoneDict(); deprecated isn't the same as
>gone...
I tend to avoid dep
Hi Danny,
Danny Yoo wrote on 08.08.2005:
>On Mon, 8 Aug 2005, Jan Eden wrote:
>
>>Is there a recommended way to receive the results of an SQL query
>>in the form I need? Or do I have to create a dictionary of
>>fieldname tuples which can be zipped with the query r
Hi,
I'd like to pack some modules in a package. Each module contains a single
class, which forces me to
from Pythonsite.Show import Page
page = Page()
...
class Page(Site.DB): #class DB from module Site in package Pythonsite
...
Is there a way to define a default class for a module whi
Hi,
I would like to untaint all parameters with which my CGI script is called.
Example:
if parameters.has_key('type'):
match = re.search('\w+', parameters['type'].value)
type = match.group()
else: type = 'page'
In Perl, I used the ternary operator to write it like this:
my $type = ($pa
Hi Kent, hi Alan,
Kent Johnson wrote on 10.08.2005:
>OK, I don't know much Perl but I don't think these two snippets do
>the same thing. For one thing the regexes are different, second in
>the Python you need to check if the match succeeds.
>
>>my $type = ($parameters{type} && ($parameters{type}
Hi Alan,
Alan G wrote on 11.08.2005:
>> I will combine Kent's and your suggestion, because he included a
>> check for an AttributeError:
>>
>
>OK, as a slightly more perl-ish solution to the no Attribute problem
>you could also do this:
>
>try:
>type = re.search('\w+', parameters['type'].val
Hi Kent,
Kent Johnson wrote on 11.08.2005:
>I don't know of any way to do exactly what you ask. However you can
>use the __init__.py module of the package to promote classes to
>package level visibility.
>
Nice - that's a good start.
Thank you,
Jan
--
Common sense is what tells you that the w
Hi,
I need to use an instance attribute as the default value for a parameter to a
method.
This obviously won't work:
page.Children()
def Children(self, id=self.id, level=2):
How can I get the id parameter to use the attribute page.id? I know I could
simply use the method call
page.Children(
Hi,
Jan Eden wrote on 26.08.2005:
>Hi,
>
>I need to use an instance attribute as the default value for a parameter to a
>method.
>
>This obviously won't work:
>
>page.Children()
>
>def Children(self, id=self.id, level=2):
>
>How can I get the id paramet
Hi,
I use the following query (simplified):
self.dbh.execute("SELECT anreise, abreise FROM buchungen WHERE ferienhaus =
'%(ferienhaus)s'" % { 'ferienhaus': ferienhaus} )
Both anreise and abreise are date fields. I initially wrote a little function
to turn ISO formatted date strings into a date
[EMAIL PROTECTED] wrote on 29.08.2005:
>Dear Python,
> How does a calculator multiply? I want to create a computer software that can
>multiply. How do I program the computer to multiply?
Could this be a spammer aiming at mailing lists?
- Jan
--
The day Microsoft makes something that doesn't s
Hi Liam,
Liam Clarke-Hutchinson wrote on 02.09.2005:
>Hi Jan,
>
>Are you using pysqlite? If so, then let me quote from the pysqlite
>docs -
>
>"pysqlite has default adapters for the date and datetime types in
>the datetime module. They will be sent as ISO dates/ISO timestamps
>to SQLite."
>
>
>Pe
Hi Danny,
Danny Yoo wrote on 05.09.2005:
>
>On Mon, 5 Sep 2005, Jan Eden wrote:
>>[Sat Sep 03 23:01:52 2005] [notice] child pid 2334 exit signal Bus
>>error (10) [Sat Sep 03 23:01:53 2005] [notice] child pid 2333 exit
>>signal Bus error (10)
>
>It looks that
Hi,
I'd like to form a list of class instances. The following does not work
(TextfieldLong, Textarea, TextfieldShort etc being class names):
fields = [
TextfieldLong(name='title', label='Seitentitel', value=''),
Textarea(name='content', label='Inhalt', value=''),
Shor
Hi,
Jan Eden wrote on 20.09.2005:
>Hi,
>
>I'd like to form a list of class instances. The following does not work
>(TextfieldLong, Textarea, TextfieldShort etc being class names):
>
>fields = [
>TextfieldLong(name='title', label='Seiten
Hi,
Orri Ganel wrote on 20.09.2005:
>As a side-note, unless you're okay with only being able to access
>those instance variables through the fields list (ie fields[0],
>fields[1], fields[2]), you may want to actually name them first.
Yes, I am fine with that - I actually prefer to have a sorted
Hi,
I just noticed that in the following environment:
class Base:
def __init__(self):
...
class Child(Base):
pass
the following statement:
child = Child()
would automatically execute the superclass __init__ method. This is exactly
what I was looking for - but in the Cookb
Kent Johnson wrote on 22.09.2005:
>This is standard behavior for any class attribute - if it's not
>defined in the derived class, the base class is checked. It's not
>special for __init__.
>
>I can't find a comprehensive reference for the way attribute lookup
>works - anyone else?
Well, I did kno
Hi,
paul brian wrote on 22.09.2005:
>
>class Base:
> def __init__(self):
> print "hello"
>
>class Child(Base):
> def __init__(self):
> Base.__init__(self)
>
This is how I did it so far. But in my program, I have 10 subclasses with
identical __init__ methods, so I can simplify th
Hi,
I experienced a strange side effect using a custom __getattr__ method.
For a certain attribute, I'd like to return the value of another attribute if
the former is not present. So I wrote:
def __getattr__(self, attrname):
if attrname == 'own_type': return self.child_type
else: Attrib
Sorry! Found the typo.
- Jan
Jan Eden wrote on 25.09.2005:
>Hi,
>
>I experienced a strange side effect using a custom __getattr__ method.
>
>For a certain attribute, I'd like to return the value of another attribute if
>the former is not present. So I wrote:
>
>d
Hi,
I used to use an extended if...elif sequence to instantiate an object and call
this object's display method afterwards:
if safe['type'] == pages:
page = Show.Page(id=safe['id'], start=safe['start'] ...),
elif safe['type'] == pages:
author = Show.Author(id=safe['id']...)
...
pag
Kent Johnson wrote on 27.09.2005:
>Jan Eden wrote:
>>The problem is that the __init__ methods of the respective classes
>>take a different number of parameters - this is why I pass the
>>whole safe_parameters dictionary.
>
>I think if you pass the dictionary as keywor
Hi,
after updating a program to use new-style classes, I am a bit confused. My
setup looks like this (simplified):
#Show.py
import Data
class Base(object):
...
class Page(Data.Page, Base):
...
class Author(Data.Author, Base):
...
#Data.py
class Base:
...
class Page(Base):
Hi Kent,
Kent Johnson wrote on 29.09.2005:
>>Data.Base has no base classes, so it is not based on a built-in
>>type: How can it be a new-style class?
>
>Data.Base is not a new-style class, but the classes in Show are. And
>properties may appear to work in old-style classes. This document
>http://
Hi,
my program uses an initial "switch" statement to create an object:
valid_types = dict(
pages=Show.Page,
syndicated=Show.Syndicated,
authors=Show.Author,
author_list=Show.AuthorList,
galleries=Show.Gallery,
pictures=Show.Picture,
slideshow=Show.SlidePicture,
tex
Hi Scott,
Scott Clausen wrote on 30.10.2005:
>As a newbie to Python I'd like to know if someone can tell me some
>strengths and weaknesses of this language. The reason I'm asking is
>a friend told me I should learn Perl over Python as it's more
>prevalent. I'm going to be using it on a Mac.
>
>I
Hi,
the module Data.py stores a number of data attributes. I'd like to structure
the storage of these attributes, either in subclasses or in dictionaries.
My first attempt was this:
class A:
templates['attr1'] = 'string'
queries['children'] = ...
class B(A):
templates['attr2']
Hi Kent,
Kent Johnson wrote on 04.11.2005:
>
>OK I'll try again. I still don't understand why you don't like using
>straight class attributes - is it to keep the size of the class
>namespace smaller?
>
Yes, and to distinguish between different kinds of attributes in the main
script. In the end, i
Hi,
I use the following construction to make sure the data attribute site_id is set
only once for each object:
def GetSiteID(self):
return self._site_id
def SetSiteID(self, value):
if not (hasattr(self, '_site_id') and self._site_id): self._site_id = value
site_id = property(GetSit
Hi Liam,
Liam Clarke wrote on 06.11.2005:
>Hi Jan,
>
>Won't this
>
>site_id = property(GetSiteID, SetSiteID)
>
>and this
>
>site_id = 1
>
>collide?
>
Yup. After writing my message, I thought about it again: the property function
gets never executed when I use the class attribute.
So I changed
Hi,
I have a number of classes, each of which should inherit from a related
superclass in another module:
class A(Super.A):
...
class B(Super.B):
...
class C(Super.C):
...
Is there a way to dynamically determine the value of Super at runtime?
Background: Depending on certain obje
Hi Kent,
Kent Johnson wrote on 19.11.2005:
>Jan Eden wrote:
>> Is there a way to dynamically determine the value of Super at
>> runtime? Background: Depending on certain object attributes which are
>> set during the object initialization, I need to use a different set
&g
Kent Johnson wrote on 19.11.2005:
>Danny Yoo wrote:
>>Here's a small example that shows how classes can be treated just
>>like any other value in Python:
>>
>> #
>> def makeYa(superclass):
>> class Ya(superclass):
>> def sayHi(self):
>>
Kent Johnson wrote on 20.11.2005:
>Use getattr() to access attributes by name. SiteA is an attribute of Templates
>and Page is an attribute of SiteA so you can get use getattr() twice to get
>what
>you want:
>
>site = getattr(Templates, self.site_name)
>self.template = getattr(site, self.templa
Hi,
Kent Johnson wrote on 20.11.2005:
>
>Use getattr() to access attributes by name. SiteA is an attribute of
>Templates and Page is an attribute of SiteA so you can get use
>getattr() twice to get what you want:
>
>site = getattr(Templates, self.site_name) self.template =
>getattr(site, self.temp
Hi,
Jan Eden wrote on 22.11.2005:
>Hi,
>
>Kent Johnson wrote on 20.11.2005:
>>
>>Use getattr() to access attributes by name. SiteA is an attribute
>>of Templates and Page is an attribute of SiteA so you can get use
>>getattr() twice to get what you wa
Hi,
I need to parse a CSV file using the csv module:
"hotel","9,463","95","1.00"
"hotels","7,033","73","1.04"
"hotels hamburg","2,312","73","3.16"
"hotel hamburg","2,708","42","1.55"
"Hotels","2,854","41","1.44"
"hotel berlin","2,614","31","1.19"
The idea is to use each single keyword (field 1)
Kent Johnson wrote on 02.12.2005:
>I'm not entirely sure how you want to interpret the data above. One
>possibility is to just change the double "" to single " before
>processing with csv. For example:
>
># data is the raw data from the whole file
>data = '''""hotel,hamburg"","1","0","0"
>""hotel,
Kent Johnson wrote on 02.12.2005:
>Jan Eden wrote:
>>I guess I need to notify the engineer responsible for the CSV
>>output and have the quoting corrected.
>
>If that is possible it is a much better solution. I hate to hack
>around bad data - much better to correct t
Hi,
I use the following loop to parse some HTML code:
for record in data:
try:
parser.feed(record['content'])
except HTMLParseError, (msg):
print "!!!Parsing error in", record['page_id'], ": ", msg
Now after HTMLParser encounters a parse error in one record, it repeats to
Hi Pawel,
Pawel Kraszewski wrote on 06.12.2005:
>Dnia wtorek, 6 grudnia 2005 16:29, Jan Eden napisa?:
>> Hi,
>>
>> I use the following loop to parse some HTML code:
>>
>> for record in data:
>> try:
>> parser.feed(record[&
Hi,
Nelson, Scott wrote on 06.12.2005:
>An unhandled exception immediately stops the execution of your code.
>
>A handled exception (try/except) does not stop code execution (unless
>you explicitly tell it to).
>
>This shows how a handled exception does not stop code execution:
>
>try:
> raise
Kent Johnson wrote on 06.12.2005:
>The parser processes up to the error. It never recovers from the
>error. HTMLParser has an internal buffer and buffer pointer that is
>never advanced when an error is detected; each time you call feed()
>it tries to parse the remaining data and gets the same erro
Hi,
I intend to use an XSLT processor, and found various modules (4suite, Sab-Pyth)
on the web. Could anyone recommend a specific module for transforming XML files?
Thanks,
Jan
--
It's overkill, of course. But you can never have too much overkill.
__
Hi,
I am about to build my first web application using the MVC pattern. Now I am
wondering which might be the best way to initialize both a model and a
presenter based on the model and its state.
My controller should look like this:
#
model = Models.ModelFactory(cgi_parameters)
view =
Hi,
is it correct that an object cannot be re-instantiated within it's __init__
method?
I tried:
class Omega:
def Display(self):
print self
class Alpha(Omega):
def __init__(self):
self = Beta()
class Beta(Omega):
def __init__(self):
pass
Hi,
after upgrading to MySQL 5 and MySQLdb 1.2.1_p2, I have the following problem:
self.db=MySQLdb.connect(host=host, user=user, passwd=passwd, db=db,
cursorclass=MySQLdb.cursors.DictCursor)
stringel = 'Some string'
stringel = self.db.escape(stringel)
File "./test.py", line 12, in ?
strin
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