Re: Is there a simpler way to modify all arguments in a function before using the arguments?
On Thursday, November 15, 2012 11:16:08 PM UTC-5, Ethan Furman wrote:
Emile van Sebille wrote:
Using a decorator works when named arguments are not used. When named
arguments are used, unexpected keyword error is reported. Is there a
simple fix?
Extend def wrapper(*args) to handle *kwargs as well
Emile
Code:
-
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
so this line ^ becomes
def wrapper(*args, **kwargs):
args = (arg.replace('_', '') for arg in args)
and add a line
for k, v in kwargs:
kwargs[k] = v.replace('_', '')
return fn(*args)
and this line ^ becomes
return fn(*args, **kwargs)
return wrapper
~Ethan~
Ethan,
I tried you code suggestions but got errors.
However, this works:
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args, **kwargs):
args = (arg.replace('_', '') for arg in args)
for kv in kwargs:
kwargs[kv] = kwargs[kv].replace('_', '')
return fn(*args, **kwargs)
return wrapper
@fix_args
def foo(a1=, a2=, b1=, b2=):
print(a1)
print(a2)
print(b1)
print(b2)
print
foo ('a1a1_x', 'a2a2_x', 'b1b1_x', 'b2b2_x')
foo (a1='a1a1_x', a2='a2a2_x', b1='b1b1_x', b2='b2b2_x')
foo ('a1a1_x', 'a2a2_x', b1='b1b1_x', b2='b2b2_x')
Bruce
--
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Re: Is there a simpler way to modify all arguments in a function before using the arguments?
bruceg113...@gmail.com wrote:
On Thursday, November 15, 2012 11:16:08 PM UTC-5, Ethan Furman wrote:
Emile van Sebille wrote:
Using a decorator works when named arguments are not used. When named
arguments are used, unexpected keyword error is reported. Is there a
simple fix?
Extend def wrapper(*args) to handle *kwargs as well
Emile
Code:
-
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
so this line ^ becomes
def wrapper(*args, **kwargs):
args = (arg.replace('_', '') for arg in args)
and add a line
for k, v in kwargs:
kwargs[k] = v.replace('_', '')
return fn(*args)
and this line ^ becomes
return fn(*args, **kwargs)
return wrapper
~Ethan~
Ethan,
I tried you code suggestions but got errors.
Right, my 'for k, v in kwargs' should have been 'for k, v in kwargs.items()'
Glad you were able to make it work!
~Ethan~
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Re: Is there a simpler way to modify all arguments in a function before using the arguments?
On Saturday, November 10, 2012 10:35:12 AM UTC-5, Aahz wrote:
In article mailman.3530.1352538537.27098.python-l...@python.org,
Peter Otten __pete...@web.de wrote:
Miki Tebeka wrote:
Is there a simpler way to modify all arguments in a function before using
the arguments?
You can use a decorator:
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
args = (arg.replace('_', '') for arg in args)
return fn(*args)
return wrapper
@fix_args
def foo(x, y):
print(x)
print(y)
I was tempted to post that myself, but he said /simpler/ ;)
From my POV, that *is* simpler. When you change the parameters for foo,
you don't need to change the arg pre-processing. Also allows code reuse,
probably any program needing this kind of processing once will need it
again.
--
Aahz (a...@pythoncraft.com) * http://www.pythoncraft.com/
Normal is what cuts off your sixth finger and your tail... --Siobhan
Using a decorator works when named arguments are not used. When named arguments
are used, unexpected keyword error is reported. Is there a simple fix?
Thanks to all,
Bruce
Code:
-
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
args = (arg.replace('_', '') for arg in args)
return fn(*args)
return wrapper
@fix_args
def foo(a1=, a2=, b1=, b2=):
print(a1)
print(a2)
print(b1)
print(b2)
foo ('a1a1_x', 'a2a2_x', 'b1b1_x', 'b2b2_x')
foo (a1='a1a1_x', a2='a2a2_x', b1='b1b1_x', b2='b2b2_x')
Results:
a1a1x
a2a2x
b1b1x
b2b2x
Traceback (most recent call last):
File C:\WORK\masterDB_Update\argtest.py, line 19, in module
foo (a1='a1a1_x', a2='a2a2_x', b1='b1b1_x', b2='b2b2_x')
TypeError: wrapper() got an unexpected keyword argument 'a1'
--
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Re: Is there a simpler way to modify all arguments in a function before using the arguments?
brucegoodst...@gmail.com wrote:
Using a decorator works when named arguments are not used. When named arguments
are used, unexpected keyword error is reported. Is there a simple fix?
Extend def wrapper(*args) to handle *kwargs as well
Emile
Code:
-
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
args = (arg.replace('_', '') for arg in args)
return fn(*args)
return wrapper
@fix_args
def foo(a1=, a2=, b1=, b2=):
print(a1)
print(a2)
print(b1)
print(b2)
foo ('a1a1_x', 'a2a2_x', 'b1b1_x', 'b2b2_x')
foo (a1='a1a1_x', a2='a2a2_x', b1='b1b1_x', b2='b2b2_x')
Results:
a1a1x
a2a2x
b1b1x
b2b2x
Traceback (most recent call last):
File C:\WORK\masterDB_Update\argtest.py, line 19, in module
foo (a1='a1a1_x', a2='a2a2_x', b1='b1b1_x', b2='b2b2_x')
TypeError: wrapper() got an unexpected keyword argument 'a1'
--
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Re: Is there a simpler way to modify all arguments in a function before using the arguments?
Emile van Sebille wrote:
brucegoodst...@gmail.com wrote:
Using a decorator works when named arguments are not used. When named
arguments are used, unexpected keyword error is reported. Is there a
simple fix?
Extend def wrapper(*args) to handle *kwargs as well
Emile
Code:
-
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
so this line ^ becomes
def wrapper(*args, **kwargs):
args = (arg.replace('_', '') for arg in args)
and add a line
for k, v in kwargs:
kwargs[k] = v.replace('_', '')
return fn(*args)
and this line ^ becomes
return fn(*args, **kwargs)
return wrapper
~Ethan~
--
http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
Aahz wrote:
In article mailman.3530.1352538537.27098.python-l...@python.org,
Peter Otten __pete...@web.de wrote:
Miki Tebeka wrote:
Is there a simpler way to modify all arguments in a function before
using the arguments?
You can use a decorator:
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
args = (arg.replace('_', '') for arg in args)
return fn(*args)
return wrapper
@fix_args
def foo(x, y):
print(x)
print(y)
I was tempted to post that myself, but he said /simpler/ ;)
From my POV, that *is* simpler. When you change the parameters for foo,
you don't need to change the arg pre-processing. Also allows code reuse,
probably any program needing this kind of processing once will need it
again.
Typical changes would be
@fix_args
def bar(x, y=None):
print(x)
print(y)
@fix_args
def baz(file, x, y):
print(s, file=file)
Do you find it obvious what
bar(a_b)
bar(a_b, y=c_d)
print? Do you find the traceback produced by the latter helpful?
Moving complexity into a helper function often makes client code simpler
because if the helper is well-tested and preferrably maintained by someone
else the part that you have to deal with becomes simpler, but the overall
complexity still increases.
A fix_args() decorator is worthwhile only if you need it more than once or
twice, and because it is hard to generalise I expect that yagni.
--
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Re: Is there a simpler way to modify all arguments in a function before using the arguments?
On Nov 9, 4:48 pm, bruceg113...@gmail.com wrote: Is there a simpler way to modify all arguments in a function before using the arguments? For example, can the below code, in the modify arguments section be made into a few statements? def someComputation (aa, bb, cc, dd, ee, ff, gg, hh): # modify arguments # -- aa = aa.replace (“_” , “”) bb= bb.replace (“_” , “”) cc = cc.replace (“_” , “”) dd = dd.replace (“_” , “”) ee = ee.replace (“_” , “”) ff = ff.replace (“_” , “”) gg = gg.replace (“_” , “”) hh = hh.replace (“_” , “”) # use the arguments # - # … I would couch this problem in a little more specific terms than trying to make this simpler. The word simple is a dangerous term, because it's so broad and subjective. By my mind, the code is already simple, but that's just my own two cents. The real problem with the code that it's a maintenance trap, because a careless developer could add the ii parameter and forget to clean the output. So the problem statement here might be more like How do I make sure future developers don't forget to fix the underscores in future args?. That's still a controversial question, but at least it's a little more specific. The other problem with the current code is that all the boilerplate distracts from the real logic of the function. That's a valid concern, although it's likely that most maintainers of the code would simply page down past the boilerplate without too much complaint. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
Miki Tebeka wrote:
Is there a simpler way to modify all arguments in a function before using
the arguments?
You can use a decorator:
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
args = (arg.replace('_', '') for arg in args)
return fn(*args)
return wrapper
@fix_args
def foo(x, y):
print(x)
print(y)
I was tempted to post that myself, but he said /simpler/ ;)
--
http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
On Sat, Nov 10, 2012 at 3:05 PM, Paul Rubin no.email@nospam.invalid wrote: Chris Angelico ros...@gmail.com writes: Contrived example: def send_email(from, to, subj, body, whatever, other, headers, you, like): That should be a dictionary with the header names as indexes. In fact there are already some email handling modules in the stdlib that represent headers that way. That's also plausible, but keyword arguments do make sense. And this was a top-of-the-head contrived example; I'm sure there are plenty of good use-cases. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
On Friday, November 9, 2012 8:16:12 PM UTC-5, Steven D'Aprano wrote: On Fri, 09 Nov 2012 20:05:26 -0500, Roy Smith wrote: In article 18134e77-9b02-4aec-afb0-794ed900d...@googlegroups.com, bruceg113...@gmail.com wrote: Is there a simpler way to modify all arguments in a function before using the arguments? For example, can the below code, in the modify arguments section be made into a few statements? def someComputation (aa, bb, cc, dd, ee, ff, gg, hh): # modify arguments # -- aa = aa.replace (³_² , ³²) bb= bb.replace (³_² , ³²) cc = cc.replace (³_² , ³²) dd = dd.replace (³_² , ³²) ee = ee.replace (³_² , ³²) ff = ff.replace (³_² , ³²) gg = gg.replace (³_² , ³²) hh = hh.replace (³_² , ³²) # use the arguments # - # You could do something like (not error checked)... def someComputation(*args): new_args = [arg.replace(_, ) for arg in args] aa, bb, cc, dd, ee, ff, gg, hh = new_args but that's pretty weird. I suspect you just want to pass a list instead of a bunch of discrete arguments. I agree with everything you say except that it is pretty weird. As far as I am concerned, it isn't weird at all. If you need named parameters: def someComputation(aa, bb, cc, dd, ee, ff, gg, hh): aa, bb, cc, dd, ee, ff, gg, hh = [arg.replace(_, ) for arg in (aa. bb, cc, dd, ee, ff, gg, hh)] ... -- Steven Thanks to all. Steve's example is the one I will try next week. Passing in lists, will work but it requires extra coding from the calling routines to build the list. Discrete arguments make sense. Also, what is the problem passing in 7 or more arguments? Thanks, Bruce -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
In article mailman.3530.1352538537.27098.python-l...@python.org,
Peter Otten __pete...@web.de wrote:
Miki Tebeka wrote:
Is there a simpler way to modify all arguments in a function before using
the arguments?
You can use a decorator:
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
args = (arg.replace('_', '') for arg in args)
return fn(*args)
return wrapper
@fix_args
def foo(x, y):
print(x)
print(y)
I was tempted to post that myself, but he said /simpler/ ;)
From my POV, that *is* simpler. When you change the parameters for foo,
you don't need to change the arg pre-processing. Also allows code reuse,
probably any program needing this kind of processing once will need it
again.
--
Aahz (a...@pythoncraft.com) * http://www.pythoncraft.com/
Normal is what cuts off your sixth finger and your tail... --Siobhan
--
http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
All,
I never used decorators before. I saw Miki Tebeka's sample code and your
rationale (Aahz) and I like it. For my application problem, decorators seem
like a good solution.
Thanks to all,
Bruce
On Saturday, November 10, 2012 10:35:12 AM UTC-5, Aahz wrote:
In article mailman.3530.1352538537.27098.python-l...@python.org,
Peter Otten __pete...@web.de wrote:
Miki Tebeka wrote:
Is there a simpler way to modify all arguments in a function before using
the arguments?
You can use a decorator:
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
args = (arg.replace('_', '') for arg in args)
return fn(*args)
return wrapper
@fix_args
def foo(x, y):
print(x)
print(y)
I was tempted to post that myself, but he said /simpler/ ;)
From my POV, that *is* simpler. When you change the parameters for foo,
you don't need to change the arg pre-processing. Also allows code reuse,
probably any program needing this kind of processing once will need it
again.
--
Aahz (a...@pythoncraft.com) * http://www.pythoncraft.com/
Normal is what cuts off your sixth finger and your tail... --Siobhan
--
http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
On Sun, Nov 11, 2012 at 12:15 AM, bruceg113...@gmail.com wrote:
Thanks to all.
Steve's example is the one I will try next week.
Passing in lists, will work but it requires extra coding from the calling
routines to build the list.
Not necessarily! Watch:
def foo(*args):
print(repr(args))
foo(Hello,world,!)
('Hello', 'world', '!')
Okay, that's not technically a list, it's a tuple, but same diff. Your
callers still see you as taking separate arguments, but you take them
as a single collection.
ChrisA
--
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Is there a simpler way to modify all arguments in a function before using the arguments?
Is there a simpler way to modify all arguments in a function before using the arguments? For example, can the below code, in the modify arguments section be made into a few statements? def someComputation (aa, bb, cc, dd, ee, ff, gg, hh): # modify arguments # -- aa = aa.replace (“_” , “”) bb= bb.replace (“_” , “”) cc = cc.replace (“_” , “”) dd = dd.replace (“_” , “”) ee = ee.replace (“_” , “”) ff = ff.replace (“_” , “”) gg = gg.replace (“_” , “”) hh = hh.replace (“_” , “”) # use the arguments # - # … -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
In article 18134e77-9b02-4aec-afb0-794ed900d...@googlegroups.com, bruceg113...@gmail.com wrote: Is there a simpler way to modify all arguments in a function before using the arguments? For example, can the below code, in the modify arguments section be made into a few statements? def someComputation (aa, bb, cc, dd, ee, ff, gg, hh): # modify arguments # -- aa = aa.replace (³_² , ³²) bb= bb.replace (³_² , ³²) cc = cc.replace (³_² , ³²) dd = dd.replace (³_² , ³²) ee = ee.replace (³_² , ³²) ff = ff.replace (³_² , ³²) gg = gg.replace (³_² , ³²) hh = hh.replace (³_² , ³²) # use the arguments # - # You could do something like (not error checked)... def someComputation(*args): new_args = [arg.replace(_, ) for arg in args] aa, bb, cc, dd, ee, ff, gg, hh = new_args but that's pretty weird. I suspect you just want to pass a list instead of a bunch of discrete arguments. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
On Fri, 09 Nov 2012 20:05:26 -0500, Roy Smith wrote: In article 18134e77-9b02-4aec-afb0-794ed900d...@googlegroups.com, bruceg113...@gmail.com wrote: Is there a simpler way to modify all arguments in a function before using the arguments? For example, can the below code, in the modify arguments section be made into a few statements? def someComputation (aa, bb, cc, dd, ee, ff, gg, hh): # modify arguments # -- aa = aa.replace (³_² , ³²) bb= bb.replace (³_² , ³²) cc = cc.replace (³_² , ³²) dd = dd.replace (³_² , ³²) ee = ee.replace (³_² , ³²) ff = ff.replace (³_² , ³²) gg = gg.replace (³_² , ³²) hh = hh.replace (³_² , ³²) # use the arguments # - # You could do something like (not error checked)... def someComputation(*args): new_args = [arg.replace(_, ) for arg in args] aa, bb, cc, dd, ee, ff, gg, hh = new_args but that's pretty weird. I suspect you just want to pass a list instead of a bunch of discrete arguments. I agree with everything you say except that it is pretty weird. As far as I am concerned, it isn't weird at all. If you need named parameters: def someComputation(aa, bb, cc, dd, ee, ff, gg, hh): aa, bb, cc, dd, ee, ff, gg, hh = [arg.replace(_, ) for arg in (aa. bb, cc, dd, ee, ff, gg, hh)] ... -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
bruceg113...@gmail.com writes:
Is there a simpler way to modify all arguments in a function before
using the arguments?
Why do you want to do that?
For example, can the below code, in the modify arguments section be
made into a few statements?
Whenever someone uses that many variables one always has to ask whether
a table would be better. But, for
def someComputation (aa, bb, cc, dd, ee, ff, gg, hh):
# modify arguments
# --
aa = aa.replace (“_” , “”)
bb= bb.replace (“_” , “”)
cc = cc.replace (“_” , “”)
dd = dd.replace (“_” , “”)
ee = ee.replace (“_” , “”)
ff = ff.replace (“_” , “”)
gg = gg.replace (“_” , “”)
hh = hh.replace (“_” , “”)
you could write (untested):
def someComputation (aa, bb, cc, dd, ee, ff, gg, hh):
def modify(s): return s.replace('_', '')
aa,bb,cc,dd,ee,ff,gg,hh = \
map(modify,[aa,bb,cc,dd,ee,ff,gg,hh])
--
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Re: Is there a simpler way to modify all arguments in a function before using the arguments?
On Sat, Nov 10, 2012 at 1:52 PM, Paul Rubin no.email@nospam.invalid wrote: bruceg113...@gmail.com writes: Is there a simpler way to modify all arguments in a function before using the arguments? Why do you want to do that? Contrived example: def send_email(from, to, subj, body, whatever, other, headers, you, like): # Okay, now translate all those into the appropriate encoding and with special characters escaped # We need to translate each one separately so that, for instance, a newline in the subject won't let you create additional headers ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
Chris Angelico ros...@gmail.com writes: Contrived example: def send_email(from, to, subj, body, whatever, other, headers, you, like): That should be a dictionary with the header names as indexes. In fact there are already some email handling modules in the stdlib that represent headers that way. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a simpler way to modify all arguments in a function before using the arguments?
Is there a simpler way to modify all arguments in a function before using the
arguments?
You can use a decorator:
from functools import wraps
def fix_args(fn):
@wraps(fn)
def wrapper(*args):
args = (arg.replace('_', '') for arg in args)
return fn(*args)
return wrapper
@fix_args
def foo(x, y):
print(x)
print(y)
--
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