Python相当于Perl的习惯做这个或那个，通常被称为“或死”？

Question

IN Perl it's quite common to do things like function() || alternative() function() || alternative() . If the first returns false it will run the second one.

How can this be easily implemented in Python?

Update

Examples (pseudocode):

x = func() or raise exeption
x = func() or print(x)
func() or print something

If possible solutions should work with Python 2.5+

Note: There is an implied assumption that you cannot modify the func() to raise exceptions, nor to write wrappers.

Answer 1

Use or : Python uses short circuit evaluation for boolean expressions:

function() or alternative()

If function returs True, the final value of this expression is determined and alternative is not evaluated at all.

Answer 2

you can use or :

function() or alternative()

also, there is conditional expression defined in PEP 308 :

x = 5 if condition() else 0

Which is sometimes useful in expressions and bit more readable.

Answer 3

function() or alternative()

机制完全一样。

Answer 4

try with or :

>>> def bye():
  return 3

>>> print bye() or 342432
3

Unfortunately, this does not work like in Perl, because in Perl, after an assignment like my $c = $d || 45; my $c = $d || 45; you have in $c the value 45 if $d is undefined. In Python you get an error NameError: name 'd' is not defined