函数中的 Python 参数

Question

For context, I have a function that is used to generate a button. The last two arguments of the function are used to fun another function when the button is pressed.

Im having problems with a button such as this, when Im trying to call the function (and arguments) createWorksheet(sheetTitle,sheetDate,sheetFilename) when the button is pressed.

I aimed to do it using this code:

button("Create Sheet",200,500,200,50,GREEN,BRIGHTGREEN,createWorksheet,sheetTitle,sheetDate,sheetFilename) 

but this gives the error

button() takes from 7 to 9 positional arguments but 11 were given

Instead I tried with the arguments in a tuple (as below)

button("Create Sheet",200,500,200,50,GREEN,BRIGHTGREEN,createWorksheet,(sheetTitle,sheetDate,sheetFilename))

but this throws an error:

createWorksheet() missing 2 required positional arguments: 'date' and 'filename'    

Any ideas please?

This is the button code to generate the function

def button(text, posX, posY, width, height, inactiveColor, activeColor,action=None,actionArgs=None):
    global buttonDown

    mouse = pygame.mouse.get_pos()
    click = pygame.mouse.get_pressed()

    if posX + width > mouse[0] > posX and posY + height > mouse[1] > posY:

        pygame.draw.rect(displays, activeColor, (posX,posY, width, height))

        if click[0] == 1 and not buttonDown and action!= None:

            if actionArgs is not None:
                action(actionArgs)
            else:
                action()

            buttonDown = True

        elif click[0] == 0:
            buttonDown = False
    else:
        pygame.draw.rect(displays,inactiveColor,(posX,posY,width,height))

    textSurf, textRect = text_objects(text, smallfont)
    textRect.center = ( (posX + (width/2)), (posY+(height/2)) )
    displays.blit(textSurf, textRect)

Answer 1

I think that the second invocation, ie using a tuple for the args, is correct. However you need to pass the arguments to the action function as positional arguments, not as a tuple.

You don't show the definition for createWorksheet() but assuming that it takes the 3 arguments from your example, you would call it like this:

        if actionArgs is not None:
            action(*actionArgs)
        else:
            action()

This unpacks the tuple into separate values, and passes these to the function. The difference is this:

args = (sheetTitle, sheetDate, sheetFilename)
action(args)    # passes a single argument of type tuple

vs.

action(*args)   # passes each element of the tuple as a positional argument.

The second case is the same as:

action(sheetTitle, sheetDate, sheetFilename)

If you have only one argument to pass, you still need to pass it as a one element tuple to button() , like this:

button("Create Sheet",200,500,200,50,GREEN,BRIGHTGREEN,createWorksheet,(sheetTitle,))