Why shortcuts and magics matter

In data analytics, you often:

• Rerun code many times
• Explore different plots and transformations
• Measure performance
• Run shell commands

Jupyter shortcuts and magic commands help you iterate much faster.

Keyboard shortcuts (classic Jupyter Notebook)

Jupyter has two main modes:

• Command mode (press EscEsc): navigate and manage cells
• Edit mode (press EnterEnter): edit inside a cell

Most useful shortcuts (Command mode)

• AA → insert cell above
• BB → insert cell below
• D, DD, D → delete selected cell
• XX → cut cell
• CC → copy cell
• VV → paste cell
• ZZ → undo delete
• MM → convert cell to Markdown
• YY → convert cell to Code
• Shift + Up/DownShift + Up/Down → select multiple cells

Most useful shortcuts (Edit mode)

• Ctrl + EnterCtrl + Enter → run cell (stay)
• Shift + EnterShift + Enter → run cell (move down)
• Alt + EnterAlt + Enter → run cell (insert new cell below)
• TabTab → autocomplete (when available)
• Ctrl + /Ctrl + / → toggle comment in selection

What are magic commands?

Magic commands are special Jupyter commands that start with:

• %% for line magics
• %%%% for cell magics

They are not standard Python syntax; they’re handled by IPython/Jupyter.

Common line magics

%time%time and %timeit%timeit

Use these to measure execution time.

%time sum(range(10_000_00))

%time sum(range(10_000_00))

%timeit%timeit runs the expression multiple times and gives an average:

%timeit sum(range(1_000_00))

%timeit sum(range(1_000_00))

%who%who and %whos%whos

Show variables currently defined.

%whos

%whos

%pwd%pwd and %cd%cd

• %pwd%pwd shows current working directory
• %cd%cd changes it

%pwd

%pwd

%cd data

%cd data

%ls%ls (list files)

%ls

%ls

Plotting magics

%matplotlib inline%matplotlib inline

Classic way to render plots inside the notebook.

%matplotlib inline

%matplotlib inline

%matplotlib notebook%matplotlib notebook (interactive)

This can enable interactive plots in the classic notebook.

%matplotlib notebook

%matplotlib notebook

Useful cell magics

%%writefile%%writefile (save code to a file)

You can write a cell’s content into a Python script.

%%writefile my_script.py
print("Hello from a file")

%%writefile my_script.py
print("Hello from a file")

%%bash%%bash (run bash commands)

If your Jupyter supports it, you can run bash scripts:

%%bash
ls -la

%%bash
ls -la

If %%bash%%bash isn’t available, you can use !! shell escapes instead.

Shell escapes with !!

Prefix a command with !! to run it in the OS shell.

!python --version

!python --version

!pip list | head

!pip list | head

Getting help quickly

Add ?? to functions

import pandas as pd
pd.DataFrame?

import pandas as pd
pd.DataFrame?

Use help()help()

help(pd.DataFrame)

help(pd.DataFrame)

Common mistakes

Mistake 1: Using magics in .py.py files

Magics only work in Jupyter/IPython, not in normal Python scripts.

Mistake 2: Forgetting to rerun earlier cells

Notebook state is incremental. If you restart the kernel, rerun setup cells.

Next

Continue to: Google Colab Walkthrough to learn cloud notebooks and GPU/TPU options.