How do I make a button pass its name to a function, when it is pressed?

Question

I have a function that creates buttons based on subfolders in a folder. It creates a button per subfolder, and gives it the name of the subfolder.

When pressed, I want the button to open another function and to pass that function its name.

def _sidepanel(self):
    curdir = "/Users/xxx/Desktop/Test/"
    layout = BoxLayout(orientation="vertical", pos_hint={"x": 0.0, "y": 0.0}, size_hint=(0.1,1))

    for folders in glob(join(curdir, "*")):
        name = basename(folders)
        btn = Button(text=name, on_press=lambda x: self._printname(name))
        layout.add_widget(btn)

    return layout

def _printname(self, name):
    print(name)

I have 5 subfolders, and I would expect a button to print its specific name, but instead they all print the name of the last folder run by the first function.

A more [mcve] snippet: [gist](https://gist.github.com/carcigenicate/ed2ed45fc180a0f694daf4e619cee510) — Carcigenicate, Feb 01 '19 at 13:12
The value of name passed to self._printname(name) is not actually substituted until the button is pressed, meaning it will use whatever the most recent value of name is every time, in this case, the last folder in the directory. — InfiniteHigh, Feb 01 '19 at 13:28
Possible duplicate of [What do (lambda) function closures capture?](https://stackoverflow.com/questions/2295290/what-do-lambda-function-closures-capture) — Carcigenicate, Feb 01 '19 at 13:36
That's the best explanation and description of a fix I could find. — Carcigenicate, Feb 01 '19 at 13:36
[Here is a question related to adding buttons in a for loop using similar syntax as the question](https://stackoverflow.com/questions/32037769/how-do-i-link-python-tkinter-widgets-created-in-a-for-loop) — InfiniteHigh, Feb 01 '19 at 13:39

score 0 · Accepted Answer · answered Feb 04 '19 at 10:17

Your last link solved my question. Thanks - just attached my edited code.

def _sidepanel(self):
    curdir = "/Users/xxx/Desktop/Test/"
    layout = BoxLayout(orientation="vertical", pos_hint={"x": 0.0, "y": 0.0}, size_hint=(0.1,1))

    layout.add_widget(Button(text="Import\nPhotos"))
    layout.add_widget(Button(text="Create\nReport"))
    layout.add_widget(Button(text="Save?"))
    layout.add_widget(Button(text="Button 4"))

    for folders in glob(join(curdir, "*")):
        name = basename(folders)
        btn = Button(text=name, on_press=lambda n=name:self._showphotos(n))
        layout.add_widget(btn)

    return layout


def _showphotos(self, entry):
    print(entry.text)

How do I make a button pass its name to a function, when it is pressed?

1 Answers1