Switch from tqdm without renaming your keywords

Porting a loop from tqdm means either rewriting every call site’s keyword arguments, or finding the ones that already mean the same thing here.

"""Keep tqdm's keyword style when you switch to progressbar.

Coming from `tqdm`, these keywords mean the same thing here: `desc` becomes
the prefix and `total` becomes `max_value` on any `ProgressBar`. `unit=`/
`unit_scale=` only show up through a widget that reads them, such as
`UnitProgress`, so this lists one explicitly alongside `Postfix` for the
live per-file status.
"""

import time

import progressbar

STEPS = 24


def main() -> None:
    widgets = [
        progressbar.Percentage(),
        ' ',
        progressbar.Bar(),
        ' ',
        progressbar.UnitProgress(),
        ' ',
        progressbar.Postfix(),
    ]
    with progressbar.ProgressBar(
        desc='Downloading',
        total=STEPS,
        unit='files',
        widgets=widgets,
        postfix='starting',
    ) as bar:
        for step in range(STEPS):
            bar.update(step + 1, postfix=f'file {step + 1}')
            time.sleep(0.005)


if __name__ == '__main__':
    main()

desc and total work on any ProgressBar: desc becomes the prefix (rendered as f'{desc}: '), and total becomes max_value when max_value isn’t given explicitly. unit=/unit_scale= don’t render anything by themselves – they only show up through a widget that reads them, such as UnitProgress() – so pass a widget list that includes one if you want them visible, as this demo does alongside Postfix() for the live per-file status.

Caveats

Not every tqdm keyword carries over. An unrecognized one, such as ncols, is silently accepted rather than raising – it has no effect and nothing warns you it was ignored, so a typo in a keyword name fails quietly instead of loudly.