On 9/16/19, Hongyi Zhao <hongyi.z...@gmail.com> wrote:
>
> What is the Difference Between quit() and exit() commands in Python?
They're different instances of the Quitter class, which is available
if site.py is imported (i.e. not with the -S command-line option).
They're created by site.setquit():
def setquit():
"""Define new builtins 'quit' and 'exit'.
These are objects which make the interpreter exit when called.
The repr of each object contains a hint at how it works.
"""
if os.sep == '\\':
eof = 'Ctrl-Z plus Return'
else:
eof = 'Ctrl-D (i.e. EOF)'
builtins.quit = _sitebuiltins.Quitter('quit', eof)
builtins.exit = _sitebuiltins.Quitter('exit', eof)
exit(code) or quit(code) closes sys.stdin and raises SystemExit(code):
>>> quit.__class__
<class '_sitebuiltins.Quitter'>
>>> print(inspect.getsource(type(quit)))
class Quitter(object):
def __init__(self, name, eof):
self.name = name
self.eof = eof
def __repr__(self):
return 'Use %s() or %s to exit' % (self.name, self.eof)
def __call__(self, code=None):
# Shells like IDLE catch the SystemExit, but listen when their
# stdin wrapper is closed.
try:
sys.stdin.close()
except:
pass
raise SystemExit(code)
For example:
>>> try:
... quit(42)
... except BaseException as e:
... print(repr(e))
...
SystemExit(42,)
>>> sys.stdin.closed
True
Alternatively, sys.exit is a builtin function that's equivalent to
`raise SystemExit(code)` but does not close sys.stdin. For example:
>>> try:
... sys.exit(42)
... except BaseException as e:
... print(repr(e))
...
SystemExit(42,)
>>> sys.stdin.closed
False
--
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