Contents
The Problem
Python is sorely missing an if statement that:
- computes and takes the value of A if and only if the predicate is true
- computes and takes the value of B if and only if the predicate is false
In C and its derivitives,
predicate ? A : B
This is extremely useful in programming and helps avoid copy and paste assignments. This is an example of poor code, because the assignment logic "x=" is copied and pasted, violating the software maintainbility and readability principle of OnceAndOnlyOnce:
if test: x=sin(cos(x)) else: x=cos(sin(x))
Accepted Solution
This is now part of Python 2.5:
A if predicate else B
which would convert the above snippet to:
x = sin(cos(x)) if test else cos(sin(x))
Discussion
Please see http://python.org/peps/pep-0308.html and google for discussions about the ternary operator (if you haven't yet).