For review: PEP 308 - If-then-else expression

[Andrew Dalke]

Erik Max Francis:
> That's not the point.  The point is whether or not the use of the
> conditional operator in those cases is justified and helps readability.
> You may not think that in the sqrt case it is more readable, but it is
> at least somewhat readable if you know what a conditional operator is.
> The point is _not_ whether or not such a thing can be recasted in some
> other form.

Not the complete point, which I would argue is:

  If the if/else expression is added to Python, will that construct
    - promote use, and if so, by how much?  (Both in the number of uses
         and the amount of improved readability)

    - promote misuse, and if so, by how much?

My analysis of C/C++ code suggests the number of uses in Python
code is on the order of about 1 every 1,000 lines.  Others have come
up with smaller numbers, down to 1 every 200 lines (but I think that
analysis is wrong).  So let's say it's 1 every 400 lines, which I still
assert is more often then it will be used in real Python code.

Now my other analysis suggests a misuse rate roughly equal to
a use rate.  Eg, people will use

  a = x if x < y else y
instead of
  a = min(x, y)

and people will do

  s = chr(48 + i if i < 10 else 55 + i)
instead of
  s = "0123456789ABCDEF"[i]

I have yet to see an analysis which suggests my estimate of misuse
rate is high, but then again there are 330 messages still pending.

                    Andrew
                    dalke at dalkescientific.com