3 ms·

return dict(x, **{'fo'+'o': 'bar'}, **y) The new syntax is some mild syntactic sugar. (Which isn't a bad thing IMO)

• orf 9y ago
  On the face of it, sure, but really it's some new bytecode that gets rid of the limitations of using kwargs like that, namely it's slow, impossible to really optimize and doesn't support duplicate keys.
• masklinn 9y ago
  Except that does not necessarily work with non-string keys (it'd depend on version and implementation IIRC). The expanded unpacking works in all cases.
• singingfish 9y ago
  And people say perl is unreadable ;)
• kamaal 9y ago
  This is the most unreadable code I've seen so far. Just skip all this and use Perl instead. You can write far more idiomatic, succinct readable code in Perl than you can in Python. The whole point of Python is to not write code this way.
  • vgy7ujm 9y ago
    This is what I have been saying for a long time. Readability in Python is an illusion.
• Sean1708 9y ago
  Did you try your example? It never worked in Python2 and it doesn't work in Python3 by design. Python 2.7.12 (default, Dec 4 2017, 14:50:18) [GCC 5.4.0 20160609] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> x = {'foo': 5, 'bar': 6} >>> y = {'foo': 7, 'baz': 9} >>> dict(x, **{'fo'+'o': 'bar'}, **y) File "<stdin>", line 1 dict(x, **{'fo'+'o': 'bar'}, **y) ^ SyntaxError: invalid syntax Python 3.5.2 (default, Nov 23 2017, 16:37:01) [GCC 5.4.0 20160609] on linux Type "help", "copyright", "credits" or "license" for more information. >>> x = {'foo': 5, 'bar': 6} >>> y = {'foo': 7, 'baz': 9} >>> dict(x, **{'fo'+'o': 'bar'}, **y) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: type object got multiple values for keyword argument 'foo' >>> {**x, 'fo'+'o': 'bar', **y} {'foo': 7, 'baz': 9, 'bar': 6}