"Fredrik Lundh" <[EMAIL PROTECTED]> wrote:
> I've said it many times, and I'll say it again: the only fundamentally
> new concept that has been added since Python 1.5.2 is generators.
> [...]
> All the rest is just coloured frosting
In my mind, the biggest thing since 1.5.2 is string methods. T
Tom Anderson wrote:
> How about detecting which environment you're in, then running one of two
> entirely different sets of code? Rather than trying to construct modern
> features in the antique environment, write code for each, using the local
> idioms. The trouble with this is that you end up wi
On Tue, 22 Nov 2005, Steven D'Aprano wrote:
> Are there practical idioms for solving the metaproblem "solve problem X
> using the latest features where available, otherwise fall back on older,
> less powerful features"?
>
> For instance, perhaps I might do this:
>
> try:
>built_in_feature
>
Alex Martelli wrote:
> > In the specific case of iter(), are there good
> > alternative ways of detecting an iterable without
> > consuming it?
>
> Not a problem I've had often, but when I did, if I recall correctly, I
> did something like:
>
> try:
> iter
> except NameError:
> def isiterable(
Alex Martelli wrote:
> "Consuming" didn't really come into consideration for the
> backwards compatibility part because only objects indexable with
> integers, 0 and up (and raising IndexError at some point) were usable in
> for statements in old Pythons, there was no "consuming".
Ah yes, of cour
Steven D'Aprano <[EMAIL PROTECTED]> wrote:
...
> In the specific case of iter(), are there good
> alternative ways of detecting an iterable without
> consuming it?
Not a problem I've had often, but when I did, if I recall correctly, I
did something like:
try:
iter
except NameError:
def i
Fredrik Lundh wrote:
> Steven D'Aprano wrote:
>
>
>>Alas and alack, I have to write code which is backwards
>>compatible with older versions of Python:
[snip]
>>What should I do when I can't rely on functions that
>>don't exist in older versions of Python?
>
>
> python 2.1 doesn't support it
Steven D'Aprano wrote:
> Alas and alack, I have to write code which is backwards
> compatible with older versions of Python:
>
> Python 2.1.1 (#1, Aug 25 2001, 04:19:08)
> [GCC 3.0.1] on sunos5
> Type "copyright", "credits" or "license" for more
> information.
> >>> iter
> Traceback (most recent
Micah Elliott wrote:
> On Nov 17, Duncan Booth wrote:
>
>>Steven D'Aprano wrote:
>>
>>>What should I do when I can't rely on functions that
>>>don't exist in older versions of Python?
>
>
>> sys.exit('Archaic Python not supported, please upgrade')
>
>
> +1 QOTW.
>
> I recently gave up o
Micah Elliott <[EMAIL PROTECTED]> wrote:
> I recently gave up on trying to support (backport to) pre-2.2 in my
> projects. It's been ~3 years since 2.2 released and that seem like a
> pretty reasonable support window.
It depends on what you're doing. If you're developing for in-house
use, you h
On Nov 17, Duncan Booth wrote:
> Steven D'Aprano wrote:
> > What should I do when I can't rely on functions that
> > don't exist in older versions of Python?
> sys.exit('Archaic Python not supported, please upgrade')
+1 QOTW.
I recently gave up on trying to support (backport to) pre-2.2 i
Steven D'Aprano <[EMAIL PROTECTED]> wrote:
> Alas and alack, I have to write code which is backwards
> compatible with older versions of Python:
> [...]
> NameError: name 'iter' is not defined
>
> What should I do when I can't rely on functions that
> don't exist in older versions of Python?
I
Steven D'Aprano wrote:
> What should I do when I can't rely on functions that
> don't exist in older versions of Python?
>
Ideally:
if 'iter' not in dir(__builtins__):
import sys
sys.exit('Archaic Python not supported, please upgrade')
Alternatively fill in the blanks with app
Roy Smith wrote:
> Now you're assuming that the message is a constant for all TypeErrors
> caused by attempting to iterate over a non-iterable object.
Yes I am, and of course you are correct that that could
change and so shouldn't be relied on.
Seems that my crappy solution is not quite as
fut
Ah, found the right solution! Thanks to Fredrik Lundh
for so gently pointing me at this post. Just one
question, if I may:-
Alex Martelli wrote:
> It's not hard...:
>
> try:
> _it = iter(whatever)
> except TypeError:
> print 'non-iterable'
> else:
> for i in _it: # etc, etc
Alas
Fredrik Lundh wrote:
> Steven D'Aprano wrote:
>
>
>>This means we're no longer assuming what the error message will be,
>>which makes our code a lot more future-proof and implementation-proof: if
>>some version of Python changes the error string from "iteration over
>>non-sequence" to something
Steven D'Aprano <[EMAIL PROTECTED]> wrote:
># Create an instance of the exception you expect:
>try:
>for i in 0:
>pass
>except TypeError, ITER_OVER_NON_SEQ:
>pass
># Now run your code...
>try:
>...blah blah blah...
>except TypeError, msg
>if str(msg) == str(ITER_OVER_NON_SE
On Wed, 16 Nov 2005 17:39:57 +0100, "Fredrik Lundh" <[EMAIL PROTECTED]> wrote:
>Rick Wotnaz wrote.
>
>> ... which leads me to belive that 'msg' is not type(str). It can be
>> coerced (str(msg).find works as expected). But what exactly is msg?
>> It appears to be of , and does not test equal to a
>
> Alex has already posted the right way to do this. can you please stop
posting crappy non-solutions to a problem that has a very simple solution (split
things up), that should be obvious to anyone who didn't sleep through exceptions
101.
--
http://mail.python.org/mailman/listinfo/python-l
Steven D'Aprano wrote:
> This means we're no longer assuming what the error message will be,
> which makes our code a lot more future-proof and implementation-proof: if
> some version of Python changes the error string from "iteration over
> non-sequence" to something else, the code should continu
On Wed, 16 Nov 2005 09:06:01 -0500, Rick Wotnaz wrote:
[cutting to the important bit]
>> except TypeError, msg:
>> if msg == "iteration over non-sequence":
>> # handle non-iterable case
> Does this in fact work on your system? On mine (2.4.1 (#65, Mar 30
> 2005, 09:13:57)
"Fredrik Lundh" <[EMAIL PROTECTED]> wrote in
news:[EMAIL PROTECTED]:
> Rick Wotnaz wrote.
>
>> ... which leads me to belive that 'msg' is not type(str). It
>> can be coerced (str(msg).find works as expected). But what
>> exactly is msg? It appears to be of , and does
>> not test equal to a strin
Rick Wotnaz wrote.
> ... which leads me to belive that 'msg' is not type(str). It can be
> coerced (str(msg).find works as expected). But what exactly is msg?
> It appears to be of , and does not test equal to a
> string.
it's an instance of the exception type, of course.
:::
if you do
rai
In article <[EMAIL PROTECTED]>,
Rick Wotnaz <[EMAIL PROTECTED]> wrote:
> Steven D'Aprano <[EMAIL PROTECTED]> wrote in
> news:[EMAIL PROTECTED]:
>
> > def foo(inputVal):
> > try:
> > for val in inputVal:
> > # do stuff
> > except TypeError, msg:
> > if msg ==
Steven D'Aprano <[EMAIL PROTECTED]> wrote in
news:[EMAIL PROTECTED]:
> def foo(inputVal):
> try:
> for val in inputVal:
> # do stuff
> except TypeError, msg:
> if msg == "iteration over non-sequence":
> # handle non-iterable case
> else:
>
On Tue, 15 Nov 2005 21:59:44 -0500, Roy Smith wrote:
> In article <[EMAIL PROTECTED]>,
> Steven D'Aprano <[EMAIL PROTECTED]> wrote:
>
>> try:
>> for item in obj:
>> do_stuff(item)
>> except TypeError, msg:
>> if msg == "iteration over non-sequence":
>> handle_non_iter
On Tue, 15 Nov 2005 21:54:07 -0500, Dan Sommers wrote:
> On Wed, 16 Nov 2005 13:12:38 +1100,
> Steven D'Aprano <[EMAIL PROTECTED]> wrote:
>
>> try:
>> for item in obj:
>> do_stuff(item)
>> except TypeError, msg:
>> if msg == "iteration over non-sequence":
>> handle_non
In article <[EMAIL PROTECTED]>,
Steven D'Aprano <[EMAIL PROTECTED]> wrote:
> try:
> for item in obj:
> do_stuff(item)
> except TypeError, msg:
> if msg == "iteration over non-sequence":
> handle_non_iterator()
> else:
> # re-raise the exception
>
On Wed, 16 Nov 2005 13:12:38 +1100,
Steven D'Aprano <[EMAIL PROTECTED]> wrote:
> try:
> for item in obj:
> do_stuff(item)
> except TypeError, msg:
> if msg == "iteration over non-sequence":
> handle_non_iterator()
> else:
> # re-raise the exception
>
[EMAIL PROTECTED] wrote:
> Maybe this helps:
Unfortunately, it doesn't. If you read the sample code
the original poster first gave, you will see that Py's
example is virtually the same as yours:
[original code]
def foo(inputVal):
if isinstance(inputVal, (list, tuple)):
for val in
Roy Smith wrote:
> You can't tell the difference between:
>
> try:
> for i in 5:
> print i + 1
> except TypeError:
> print "non-iterable"
>
> and
>
> try:
> for i in ["one", "two", "three"]:
> print i + 1
> except TypeError:
> print "can't add string and integer"
try:
for
Roy Smith <[EMAIL PROTECTED]> wrote:
...
> TypeError: iteration over non-sequence
>
> I was kind of hoping for a more specific exception than TypeError.
> You can't tell the difference between:
>
> try:
> for i in 5:
> print i + 1
> except TypeError:
> print "non-iterable"
>
> and
>
On Tue, 15 Nov 2005 11:26:23 -0800, py wrote:
> Dan Sommers wrote:
>> Just do it. If one of foo's callers passes in a non-iterable, foo will
>> raise an exception, and you'll catch it during testing
>
> That's exactly what I don't want. I don't want an exception, instead I
> want to check to se
[EMAIL PROTECTED] wrote:
> Maybe this helps:
>
> >>> import types
> >>> def foo(inputVal):
> inValType = type(inputVal)
> if inValType==types.ListType or inValType==types.TupleType:
And what of user-created types that are iterable?
What of user-created iterable types that don't inher
How about hasattr("__iter__")?
Regards,
Karsten.
--
http://mail.python.org/mailman/listinfo/python-list
On Tue, 15 Nov 2005 14:06:45 -0500, Dan Sommers wrote:
> On 15 Nov 2005 11:01:48 -0800,
> "py" <[EMAIL PROTECTED]> wrote:
>
>> I have function which takes an argument. My code needs that argument
>> to be an iterable (something i can loop over)...so I dont care if its a
>> list, tuple, etc. So
Maybe this helps:
>>> import types
>>> def foo(inputVal):
inValType = type(inputVal)
if inValType==types.ListType or inValType==types.TupleType:
for val in inputVal:
print val
else:
print 'Wrong input Type'
>>> list = [1,2,3,4]
>>> foo(list)
1
2
3
4
>>
On 15 Nov 2005 11:26:23 -0800 in comp.lang.python, "py"
<[EMAIL PROTECTED]> wrote:
>Dan Sommers wrote:
>> Just do it. If one of foo's callers passes in a non-iterable, foo will
>> raise an exception, and you'll catch it during testing
>
>That's exactly what I don't want. I don't want an exceptio
On 2005-11-15, py <[EMAIL PROTECTED]> wrote:
> Dan Sommers wrote:
>> Just do it. If one of foo's callers passes in a non-iterable, foo will
>> raise an exception, and you'll catch it during testing
>
> That's exactly what I don't want. I don't want an exception, instead I
> want to check to see i
In article <[EMAIL PROTECTED]>,
py <[EMAIL PROTECTED]> wrote:
>I have function which takes an argument. My code needs that argument
>to be an iterable (something i can loop over)...so I dont care if its a
>list, tuple, etc.
My first thought was to just write your loop inside a try block and
catch
Thanks for the replies. I agree with Jean-Paul Calderone's
suggestion...let the exception be raised.
Thanks.
--
http://mail.python.org/mailman/listinfo/python-list
Hi!
py wrote:
> Dan Sommers wrote:
>
>>Just do it. If one of foo's callers passes in a non-iterable, foo will
>>raise an exception, and you'll catch it during testing
>
>
> That's exactly what I don't want. I don't want an exception, instead I
> want to check to see if it's an iterableif
py wrote:
> Dan Sommers wrote:
>
>>Just do it. If one of foo's callers passes in a non-iterable, foo will
>>raise an exception, and you'll catch it during testing
>
> That's exactly what I don't want. I don't want an exception, instead I
> want to check to see if it's an iterableif it is co
marduk wrote:
> On Tue, 2005-11-15 at 11:01 -0800, py wrote:
>
>>I have function which takes an argument. My code needs that argument
>>to be an iterable (something i can loop over)...so I dont care if its a
>>list, tuple, etc. So I need a way to make sure that the argument is an
>>iterable befo
On 15 Nov 2005 11:26:23 -0800, py <[EMAIL PROTECTED]> wrote:
>Dan Sommers wrote:
>> Just do it. If one of foo's callers passes in a non-iterable, foo will
>> raise an exception, and you'll catch it during testing
>
>That's exactly what I don't want. I don't want an exception, instead I
>want to c
Dan Sommers wrote:
> Just do it. If one of foo's callers passes in a non-iterable, foo will
> raise an exception, and you'll catch it during testing
That's exactly what I don't want. I don't want an exception, instead I
want to check to see if it's an iterableif it is continue, if not
return
On Tue, 2005-11-15 at 11:01 -0800, py wrote:
> I have function which takes an argument. My code needs that argument
> to be an iterable (something i can loop over)...so I dont care if its a
> list, tuple, etc. So I need a way to make sure that the argument is an
> iterable before using it. I kno
On 15 Nov 2005 11:01:48 -0800,
"py" <[EMAIL PROTECTED]> wrote:
> I have function which takes an argument. My code needs that argument
> to be an iterable (something i can loop over)...so I dont care if its a
> list, tuple, etc. So I need a way to make sure that the argument is an
> iterable befo
I have function which takes an argument. My code needs that argument
to be an iterable (something i can loop over)...so I dont care if its a
list, tuple, etc. So I need a way to make sure that the argument is an
iterable before using it. I know I could do...
def foo(inputVal):
if isinstance
I have function which takes an argument. My code needs that argument
to be an iterable (something i can loop over)...so I dont care if its a
list, tuple, etc. So I need a way to make sure that the argument is an
iterable before using it. I know I could do...
def foo(inputVal):
if isinstance
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