How to step through Python code to help debug issues?

In Java/C# you can easily step through code to trace what might be going wrong, and IDE's make this process very user friendly.

Can you trace through python code in a similar fashion?

Yes! There's a Python debugger called pdb just for doing that!

You can launch a Python program through pdb via python -m pdb myscript.py.

There are a few commands you can then issue, which are documented on the pdb page.

Some useful ones to remember are:

• b: set a breakpoint
• c: continue debugging until you hit a breakpoint
• s: step through the code
• n: to go to next line of code
• l: list source code for the current file (default: 11 lines including the line being executed)
• u: navigate up a stack frame
• d: navigate down a stack frame
• p: to print the value of an expression in the current context

If you don't want to use a command line debugger, some IDEs like Pydev, Wing IDE or PyCharm have a GUI debugger. Wing and PyCharm are commercial products, but Wing has a free "Personal" edition, and PyCharm has a free community edition.