On Tue, Apr 1, 2014 at 6:07 PM, Patti Scott <pscott...@yahoo.com> wrote:
> I've been cheating: comment out the conditional statement and adjust the
> indents. But, how do I make my program run with if __name__ == 'main':
> main() at the end? I thought I understood the idea to run a module called
> directly but not a module imported. My program isn't running, though.
The statement is:
if __name__ == '__main__':
You’re missing the double underscores on both sides of __main__. If
you added them in, this would work.
> Below is the last textbook example (Python Programming, Zelle) I reworked.
> Runs when I comment out the conditional statement. I am self-studying.
> Python 2.7.3, Notepad++, Windows PowerShell.
>
> # calc.pyw
> # a 4-function calculator that uses Python arithmetic
> # illustrates use of objects and lists to build a simple GUI
>
> from graphics import *
> from button import Button
>
> class Calculator:
It’s better to inherit from object (i.e. use `class
Calculator(object):`) in this case. Saves you a lot of trouble when
you encounter new-style-only things.
> # this class implements simple calculator GUI
>
> def __init__(self):
> # create window for calculator
> win = GraphWin('calculator')
> win.setCoords(0,0,6,7)
> win.setBackground('slategray')
> self.win = win
> # now create the widgets
> self.__createButtons()
> self.__createDisplay()
>
> def __createButtons(self):
> # create list of buttons
> # start with all the standard-sized buttons
> # bSpecs gives center coords and labels of buttons
> bSpecs = [(2,1,'0'), (3,1,'.'),
> (1,2,'1'), (2,2,'2'), (3,2,'3'), (4,2,'+'), (5,2,'-'),
> (1,3,'4'), (2,3,'5'), (3,3,'6'), (4,3,'*'), (5,3,'/'),
> (1,4,'7'), (2,4,'8'), (3,4,'9'), (4,4,'<-'), (5,4,'C')]
> self.buttons = []
> for (cx,cy, label) in bSpecs:
> self.buttons.append(Button(self.win, Point(cx,cy), .75,.75,
> label))
> # create the larger equals button
> self.buttons.append(Button(self.win, Point(4.5,1), 1.75, .75, '='))
> # activate all buttons
> for b in self.buttons:
> b.activate()
>
> def __createDisplay(self):
> bg = Rectangle(Point(.5,5.5), Point(5.5, 6.5))
> bg.setFill('white')
> bg.draw(self.win)
> text = Text(Point(3,6), "")
> text.setFace('courier')
> text.setStyle('bold')
> text.setSize(16)
> text.draw(self.win)
> self.display = text
>
> def getButton(self):
> # waits for button to be clicked and returns label of that button
> while True:
> p = self.win.getMouse()
> for b in self.buttons:
> if b.clicked(p):
> return b.getLabel() # method exit
>
> def processButton(self, key):
> # updates calculator display for press of this key
> text = self.display.getText()
> if key == 'C':
> self.display.setText("")
> elif key == "<-":
> # backspace, slice off the last character
> self.display.setText(text[:-1])
> elif key == '=':
> # evaluate the expression and display result
> # the try ... except mechanism catches errors in the
> # formula being evaluated
> try:
> result = eval(text)
> except:
> result ='ERROR'
> self.display.setText(str(result))
> else:
> # normal key press, append it to end of display
> self.display.setText(text+key)
>
> def run(self):
> # infinite event loop to process button clicks
> while True:
> key = self.getButton()
> self.processButton(key)
>
> #this runs the program
> if __name__ == 'main':
> #first create a calulator object
> theCalc = Calculator()
> # now call the calculator's run methond
> theCalc.run()
>
>
>
> and I get
>
> PS C:\Users\Owner\Py Programs> python calc.py
> PS C:\Users\Owner\Py Programs>
>
>
>
> Thanks
>
>
>
>
>
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--
Chris “Kwpolska” Warrick <http://kwpolska.tk>
PGP: 5EAAEA16
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