Wrong math with Python? -

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just starting out python, mistake, but...

i'm trying out python. use calculator, , i'm working through tutorials.

i ran weird today. wanted find out 2013*2013, wrote wrong thing , wrote 2013*013, , got this:

>>> 2013*013 22143

i checked calculator, , 22143 wrong answer! 2013 * 13 supposed 26169.

why python giving me wrong answer? old casio calculator doesn't this...

because of octal arithmetic, 013 integer 11. 

>>> 013 11

with leading zero, 013 interpreted base-8 number , 1*81 + 3*80 = 11.

note: behaviour changed in python 3. here particularly appropriate quote pep 3127

the default octal representation of integers silently confusing people unfamiliar c-like languages. extremely easy inadvertently create integer object wrong value, because '013' means 'decimal 11', not 'decimal 13', python language itself, not meaning humans assign literal.


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