Change default repr in interactive python from builtins.repr to reprlib.repr

Question

On the interactive Python prompt, when I don't bind the output of an expression foo to a name, Python will write the output of builtins.repr(foo) to the terminal.

In newer versions of Python, there exists an alternative repr implementation that will not flood the screen for objects with a long string representation, like this:

In [297]: import random, string, reprlib

In [298]: long_str = ''.join(random.choice(string.ascii_letters) for _ in range(1000))

In [299]: print(repr(long_str))
'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'

In [300]: print(reprlib.repr(long_str))
'LcOKLSfEifoh...CKmpTICujAJsA'

In [301]: long_str
Out[301]: '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'

Can I somehow tell Python to use reprlib.repr instead of builtin.repr for representing un-assigned output in the interactive prompt? I'm interested preferably in answers that work for any Python shell, or otherwise in answers that work at least for IPython.

Answer 1

What you are looking for is likely sys.display_hook: http://docs.python.org/2/library/sys.html#sys.displayhook.