Highly unlikely. I'd say impossible, unless you type a different value for
x
of course. By the time the input() function returns, the result is already
a float. Wrapping it in float() again cannot possibly change the value. If
you have found a value that does change, please tell us what it is.
The only examples I can think of that will behave that way involve NANs
and
INFs. If you don't know what they are, don't worry about it, and forget I
mentioned them. For regular floating point values, I can't think of any
possible way that float(input(x)) and input(x) could give different
results.
No, the calculation returns in neither NaN or Inf at any point.
float(x) converts x into a float.
- if x is already a float, it leaves it unchanged;
- if x is a string, it converts it to the nearest possible float;
- if x is some other numeric value (e.g. int, Decimal or Fraction,
but not complex) it converts it to the nearest possible float.
float(input()) is a waste of time. The dangerous part happens in the call
to
input(): a malicious user could type a Python command, and run arbitrary
code; or they could type something like "10**100**100" and lock up your
computer. Calling float *after* the call to input doesn't do anything.
In Python 3.x, raw_input is gone, but float(input()) is safe -- it is
exactly equivalent to float(raw_input()) in Python 2.x.
One other difference between Python 2.7 and 3.3 is that they sometimes
display floats slightly differently. Sometimes 3.3 will show more decimal
places:
Thanks for that, I'll post the problematic code here shortly.
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