On 18.03.07 22:28:12, Shriramana Sharma wrote:
>
> In the same #08, if I remove the word self from the line:
>
> self.emit(QtCore.SIGNAL("angleChanged(int)"), self.currentAngle)
>
> I get an error:
>
> Traceback (most recent call last):
> File "./008.py.showserror-buthowdoesitwork", line 62, in setAngle
> self . emit ( SIGNAL ( "angleChanged ( int )" ), currentAngle )
> NameError: global name 'currentAngle' is not defined
>
> But the program still works normally. How?Because no object listens to the signal emitted here, thats IIRC something that is used in a later tutorial. > 4) > > In #02, the last but one line has a semicolon at the end. This is C > syntax, not Python syntax. But still Python executes the program without > any warning or error. How? Read you python book again, a semicolon is proper Python syntax, but its not necessary unless you want to put multiple statements onto the same line > 5) > > Why do the tutorials not use tr() for user visible strings? Probably because the Qt translations are not covering the examples > 6) > > I observed that a large part of the functions in the PyQt API take self > as the first object (to emphasize that it should be called only on an > instance of the class) but the calls in the examples do not include self > as the first item. How is it that Python doesn't throw any errors? Uhm, they do generally by doing self.foobar(). In that case Python calls Class.foobar(self). > 7) > > If there is no need to include "self", then why is it necessary to say > "self" in the QWidget __init__ constructor whenever I subclass QWidget > within PyQt? See above it is necessary. Andreas -- Be cautious in your daily affairs.
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