Polite error messages in IPython¶

IPython allows registering a custom exception hook, which lets you do whatever you want when an error occurs.

If you want to hide the scary details of tracebacks for a bit, you might use this.

Here is an example showing a specific error message for NameErrors, and showing just the error message instead of a traceback for the rest.

Careful! Eliminating the traceback can make it a lot harder to find where the mistake is.

In [1]:

def polite_errors(ip, etype, evalue, tb, tb_offset=None):
    if etype is NameError:
        print("Oops! looks like {}."
              " Did you forget something or make a typo?".format(evalue))
    # elif other special errors you can make nice
    else:
        # fallback on just error type and message (no traceback)
        print("%s: %s" % (etype.__name__, evalue))
    
get_ipython().set_custom_exc((Exception,), polite_errors)

In [2]:

undefined

Oops! looks like name 'undefined' is not defined. Did you forget something or make a typo?

In [3]:

{}['a']

KeyError: 'a'

In [4]:

1/0

ZeroDivisionError: division by zero

In [4]:

def foo()
    pass

SyntaxError: invalid syntax (<ipython-input-5-af92d274abf2>, line 1)