Understanding Python logic

Question

Using Python 3.4, wondering how does this loop processing?

while SyntaxError:
    print ("Hi")

It's an infinite loop, how does this while loop running? It's an exception but..?

Because the SyntaxError class evaluates truthy in a Boolean context. This is equivalent to while True, that it's an Exception is irrelevant. — jonrsharpe
– jonrsharpe, Commented Jan 29, 2015 at 8:49

Jon Clements · Accepted Answer · 2015-01-29 08:49:24Z

4

Exceptions are just objects unless they're raised - bool(SyntaxError) is True, so your loop is effectively while True:

answered Jan 29, 2015 at 8:49

Jon Clements

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Comments

Tanveer Alam · Accepted Answer · 2015-01-29 08:54:32Z

3

Boolean value of SyntaxError is True.

>>> bool(SyntaxError)
True

That is why while loop is going in infinite loop because while SyntaxError: is equivalent to while True: condition.

while SyntaxError:
    print ("Hi")

answered Jan 29, 2015 at 8:49

Tanveer Alam

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