tryexcept#

class tryexcept(message=None, die=None, catch=None, verbose=1, history=None)[source]#

Bases: suppress

Simple class to catch exceptions in a single line

Effectively an alias to contextlib.suppress(), which itself is a programmatic equivalent to using try-except blocks.

By default, all errors are caught. If catch is not None, then by default raise all other exceptions; if die is an exception (list of exceptions), then by default suppress all other exceptions.

Due to Python’s fundamental architecture, exceptions can only be caught inside a with statement, and the with block will exit immediately as soon as the first exception is encountered.

Parameters:

  • message (str) – a custom message to print; “<EXCEPTION>” will be replaced in the message with the text of the exception

  • die (bool/exception) – default behavior of whether to raise caught exceptions; or, exceptions to die on (others to catch)

  • catch (exception) – one or more exceptions to catch regardless of “die”

  • verbose (bool) – whether to print caught exceptions (0 = silent, 1 = error type, 2 = full error information)

  • history (list/tryexcept) – a tryexcept object, or a list of exceptions, to keep the history (see example below)

Examples:

# Basic usage
values = [0,1]
with sc.tryexcept(): # Equivalent to contextlib.suppress(Exception)
    values[2]

# Raise only certain errors
with sc.tryexcept(die=IndexError): # Catch everything except IndexError
    values[2]

# Catch (do not raise) only certain errors, and print full error information
with sc.tryexcept(catch=IndexError, verbose=2): # Raise everything except IndexError
    values[2]

# Storing the history of multiple exceptions
tryexc = None
for i in range(5):
    with sc.tryexcept(history=tryexc) as tryexc:
        print(values[i])
tryexc.traceback()

# With a custom message
with sc.tryexcept('Caught exception: <EXCEPTION>'):
    values[2]
New in version 2.1.0.
New in version 3.0.0: renamed “print” to “traceback”; added “to_df” and “disp” options
New in version 3.1.0: renamed “exceptions” to “data”; added “exceptions” property
New in version 3.2.3: “message” argument

Attributes

died

Whether or not any exceptions were encountered

exception

Retrieve the last exception, if any

exceptions

Retrieve the last exception, if any

Methods

traceback(which=None, tostring=False)[source]#

Print the exception (usually the last)

Parameters:

  • which (int/list) – which exception(s) to print; if None, print all

  • tostring (bool) – whether to return as a string (otherwise print)

New in version 3.1.0: optionally print multiple tracebacks

to_df()[source]#

Convert the exceptions to a dataframe; most useful with multiple exceptions

property exceptions#

Retrieve the last exception, if any

property exception#

Retrieve the last exception, if any

property died#

Whether or not any exceptions were encountered