different behavior of pressed vs clicked with lambdas

[VirtualFloat]

I'm using lambda functions to define the actions for dynamically generated buttons. To "freeze" the value of the loop variable "i" assign it to a local variable "n" in the way described here https://docs.python.org/3/faq/programming.html#why-do-lambdas-defined-in-a-loop-with-different-values-all-return-the-same-result

This works fine for 'pressed',

button.pressed.connect(lambda a=i : print(f'pressed {a}'))

--> "pressed 7"

but somehow fails for 'clicked'.

button.clicked.connect(lambda a=i: print(f'clicked {a}'))

--> "clicked False"

Reproduce:

from PySide2.QtWidgets import QApplication, QWidget, QPushButton, QVBoxLayout

app = QApplication()

window = QWidget()
layout = QVBoxLayout()

for i in range(10):
    button = QPushButton()

    if i > 4:
        button.setText(f'pressed {i}')
        button.pressed.connect(lambda a=i : print(f'pressed {a}'))
    else:
        button.setText(f'clicked {i}')
        button.clicked.connect(lambda a=i: print(f'clicked {a}'))

    layout.addWidget(button)

window.setLayout(layout)

window.show()

app.exec_()

I fail to understand why this happens. Is there a fundamental difference in the way that 'pressed' and 'clicked' are handled? Or is this a bug?

[eyllanesc]

@VirtualFloat Change to:

• button.clicked[bool].connect(lambda checked, a=i: print(f'clicked {a}'))

OR

• button.clicked.connect(lambda *args, a=i: print(f'clicked {a}'))

See https://stackoverflow.com/a/65185119/6622587 for more information.

[VirtualFloat]

Ah, so clicked gets an argument where pressed doesn't. Thanks!

I like the button.clicked.connect(lambda *args, a=i: print(f'clicked {a}')) solution because it will work even if the signature would change.