7.7 The conditional operator
The conditional operator provides a compact means of inserting conditional expressions. Following the syntax of C, it takes three arguments and is written as a ? b : c. The first argument, a is a truth criterion to be tested. If the criterion is true, then the operator returns its second argument b as its output. Otherwise, the function’s third argument c is returned.
pyxplot> f(x) = (x0)?x:0