How to debug?

[Chun-Yang]

Thank you for your awesome challenges.

I am new to python, I know there is print and pdb.set_trace().

1. Could you tell me where is the printed message?
2. And how to make pdb.set_trace() work?

[donnemartin]

Hi Chun-Yang,

To debug just add the following line to the Code cell where you want the debugger to start:

import pdb; pdb.set_trace()

For example, you would add it like this:

def unique_chars_hash(string):
    import pdb; pdb.set_trace() # Start debugger when this line is hit
    chars_set = set()
    for char in string:
        if char in chars_set:
            return False
        else:
            chars_set.add(char)
    return True

Then run both the Code and Unit Test cells (either through the menu "Cell", or through a shortcut such as [shift + enter] or [control + enter].

This will drop you into the pdb debugger where you can issue commands like the following to l(ist) the source code:

l

or n(ext):

n

For a list of all pdb commands, refer to this link.

-Donne