* Steven D'Aprano:
On Wed, 27 Jan 2010 18:29:25 +0100, Alf P. Steinbach wrote:
The main problem with the incompatibility is for porting code, not for
writing code from scratch.
Correct. It's a trivial problem, but still a problem.
It's also a problem wrt. learning the language.
This makes no sense. Why is it harder to learn
print(x, y, z)
than this?
print x, y, z
I think it's actually easier to learn just the 3.x form.
But it's more difficult to learn that there are /two different/ syntactic forms,
depending on which version of Python you're using and in addition depending on
__future__ declarations!
E.g., picking up some example code from the web, and it does not work...
The first case is like the other functions you have to learn, like len().
In fact, many newbies to Python put unneeded parentheses around arguments
to print simply because they assume it is a function.
I would argue that the new print function is *simpler* to learn. It is
more consistent with other built-ins, and has fewer magic idioms to
learn.
Yes, yes, yes, I agree.
Instead of:
print >>fileObj, x, y, z
you use regular function syntax with a meaningful keyword:
print(x, y, z, file=fileObj)
If you want suppress the newline at the end of each print:
print x, y, z, # note the final comma
compared to:
print(x, y, z, end='')
Actually I thought the final comma thing was nice. It was like Basic. I think
the 2.x 'print' must have been modeled on Basic's 'print'.
If you want to change the space between elements, instead of:
sys.stdout.write(str(x) + "*" + str(y) + "*" + str(z) + '\n')
you use:
print(x, y, z, sep='*')
If you want to override the behaviour of print in a module, instead of
having to edit the source code of the module (which might not even be
available), all you need to do is monkey-patch it:
import module
module.print = myprint
>>> import builtins
>>>
>>> org_print = print
>>> builtins.print = 666
>>>
>>> print( "trallala" )
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'int' object is not callable
>>> org_print( "but is that really so smart?" )
but is that really so smart?
>>> _
Cheers,
- Alf
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