On 2010-12-06 09:04:00 -0800, Peter Otten said:
TomF wrote:
I'm aggravated by this behavior in python:
x = "4"
print x < 7 # prints False
The issue, of course, is comparisons of incompatible types. In most
languages this throws an error (in Perl the types are converted
silently). In Python this comparison fails silently. The
documentation says: "objects of different types *always* compare
unequal, and are ordered consistently but arbitrarily."
I can't imagine why this design decision was made. I've been bitten by
this several times (reading data from a file and not converting the
numbers before comparison). Can I get this to throw an error instead
of failing silently?
This change would break a lot of code, so it could not be made within the
2.x series. However:
Python 3.1.1+ (r311:74480, Nov 2 2009, 15:45:00)
[GCC 4.4.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
"4" < 7
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unorderable types: str() < int()
Thanks. I was hoping there was something I could do for 2.x but I
suppose this will have to do.
But I'm mystified by your statement, "this change would break a lot of
code". Given that the semantics are virtually random, how could code
depend on this?
-Tom
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