python中部分函数的参数

Question

I have a function defined like this:

def func(self, boolVal):

and I want to create a connection between QPushButton() and this function like this:

self.button1.clicked.connect(partial(self.func, False))

when I run this, it tells me that func() takes exactly 2 arguments (3 given) anyone knows why this could happened?

Answer 1

functools.partial works fine.

See following example:

from functools import partial
from PyQt4.QtGui import *

class MyWindow(QWidget):
    def __init__(self):
        super(QWidget, self).__init__()
        self.button = QPushButton('test', parent=self)
        self.button.clicked.connect(partial(self.func, False))
        self.button.show()
    def func(self, boolVar):
        print boolVar

app = QApplication([])
win = MyWindow()
win.show()
app.exec_()

If you still get error replace func signature with:

def func(self, boolVar, checked):
    print boolVar

Answer 2

The first argument is the self parameter, which is bound when you write self.func . The second argument is the False you supplied to partial , so when Qt calls it with a third bool checked parameter from QPushButton.clicked you end up with 3 arguments.

Just write:

self.button1.clicked.connect(self.func)

However, the checked parameter is optional so func should be defined as:

def func(self, checked=False):