4 ms·

In Py2.7 you need: from __future__ import print_function to get the print("hello") behaviour.

• dylz 10y ago
  I don't remember ever having to do that, and my intro to cs class was py3 - I don't really run 2.7 day to day, is this a specific version? airbears2-10-142-34-161:~ ecx$ echo 'print("hello")' >0.py airbears2-10-142-34-161:~ ecx$ python2.7 0.py hello airbears2-10-142-34-161:~ ecx$ python2.7 -V Python 2.7.10
• geoelectric 10y ago
  No, because the () just ends up being a no-op as grouping parentheses in the expression in Python 2. What the import from __future__ does is make the original non-parens version illegal syntax in Python 2. You have to treat it like a function call with that import.
  • BerislavLopac 10y ago
    There is another, less obvious difference: in Python 2, if you print multiple items in parentheses, you're actually printing a tuple: >>> print "foo", 1, 2, "bar", "baz" foo 1 2 bar baz >>> print("foo", 1, 2, "bar", "baz") ('foo', 1, 2, 'bar', 'baz') >>> from __future__ import print_function >>> print("foo", 1, 2, "bar", "baz") foo 1 2 bar baz
    • geoelectric 10y ago
      True, that, behavior-wise. It's the comma that actually defines the tuple, though, hence (1) being different than (1,) and x = 1,2 assigning (1,2). In the particular case of a print statement, the grouping parens disambiguate between the comma meaning multiple args and a single arg that's a tuple, once Python 2 implicitly wraps the entire right side with function calling parens. In the end it's really a form of operator precedence. The from __future__ version behaves differently only because the function calling parens are now explicit and so tuple grouping parens must be added too if desired.