Step 4: Choose your own widgets

The bar’s built-in display won’t always be what you want on screen. This step replaces it entirely with a hand-picked, explicit list of widgets.

"""Replace the default widget set with your own list.

`widgets=[...]` overrides everything `ProgressBar` would otherwise have
picked based on `max_value` -- the previous step's percentage, bar and ETA
are gone unless you list them again yourself.
"""

import time

import progressbar


def main() -> None:
    widgets = [
        progressbar.Percentage(),
        ' ',
        progressbar.Bar(),
        ' ',
        progressbar.ETA(),
    ]
    with progressbar.ProgressBar(max_value=100, widgets=widgets) as bar:
        for i in range(100):
            time.sleep(0.01)
            bar.update(i + 1)


if __name__ == '__main__':
    main()

The previous step let ProgressBar pick its own display based on max_value. Here the constructor gains a widgets=widgets argument, where widgets is a plain list built before the call: [progressbar.Percentage(), ' ', progressbar.Bar(), ' ', progressbar.ETA()]. Passing widgets overrides everything ProgressBar would otherwise have picked – only what is listed is shown, in the order listed, including the plain ' ' strings used here to space the widgets apart.

Next: Step 5: Print safely with redirect_stdout.