How to Use Progress Bar in Jupyter Notebook (light blue bar with question mark denominator explained)

jupyter-progress-bar.md

How to Use Progress Bar in Jupyter Notebook

Qin Yu, Apr 2020

• How to Use Progress Bar in Jupyter Notebook
  • Install ipywidgets
  • Install tqdm
  • Use tqdm in loop
  • tqdm no ETA
    • e.g. Use tqdm with os.scandir()

Install ipywidgets

ipywidgets are interactive HTML widgets for Jupyter notebooks, JupyterLab and the IPython kernel.

pip install ipywidgets
jupyter nbextension enable --py widgetsnbextension

Install tqdm

pip install tqdm

Use tqdm in loop

IPython/Jupyter is supported via the tqdm.notebook submodule:

from tqdm.notebook import trange, tqdm
from time import sleep

for i in trange(3, desc='1st loop'):
    for j in tqdm(range(100), desc='2nd loop'):
        sleep(0.01)

tqdm no ETA

Some times the progress bar is showing 23/? in light blue, saying its currently on the 23rd item without the knowledge of a total.

e.g. Use tqdm with os.scandir()

This will give a light blue progress bar whose total task number is ?:

with os.scandir(path) as dir_img:
    for entry in tqdm(path):  # `tqdm.notebook.tqdm()` doesn't work with `os.scandir()` directly
        if entry.name.endswith(".py") and entry.is_file():
            pass

By telling tqdm() the explicit form of iterator it is dealing with, a proper bar is shown. Just list() the os.scandir():

with os.scandir(path) as dir_img:
    for entry in tqdm(list(path)):  # `tqdm.notebook.tqdm()` doesn't work with `os.scandir()` directly
        if entry.name.endswith(".py") and entry.is_file():
            pass