4 ms·

Python version: exec "print 'Hello world'\n" * 100

• antirez 14y ago
  that reminds me why I don't like Python. Ad-hoc tools (many) instead of a few general concepts working well together. Btw at interview time this solution would not be acceptable, because you are using still a built-in language construct for looping.
  • masklinn 14y ago
    > because you are using still a built-in language construct for looping. That... makes no sense, the code is not looping anywhere. And if you could somehow disqualify this bit, then recursion most definitely wouldn't qualify.
  • lloeki 14y ago
    Well then you don't seem to know python and focus on some red herrings, because it's much more of the latter than the former. The example leverages general concepts such as duck typing and defining __mul__ for a string as doing something thoughtful.
  • hythloday 14y ago
    Huh? This is a specific case of the * operator, which is overloaded for type string to return a repetition of the string. The only ad-hoc in the example is the print statement, which is gone in 3.2. How do you know the __mul__ operator overload for string is implemented with iteration?
    • lloeki 14y ago
      > This is a specific case of the * operator, which is overloaded It is not operator overloading in the strictest sense, but more of duck typing. In Python (and Ruby), operators are syntactic sugar for method calls on the first operand. Operator overloading on the contrary suggests a function add(a, b) that reacts differently through polymorphism (i.e according to the types of its arguments). The distinction is important as overloading and polymorphism simply do not exist in Ruby and Python, only overriding.
      • hythloday 14y ago
        My hope in using the phrase "operator overloading" was to bring to mind the familiar concept of operator ad-hoc polymorphism (which I would maintain duck typing is an example of) rather than to misleadingly describe the internals of the Python language. Nonetheless you are quite right on the details.
  • 430gj9j 14y ago
    You're right, Python isn't beautifully minimal. But the Scheme version is boring ;) Rather than asking the interview candidate to use recursion for a problem that shouldn't be solved using recursion (unless in a language where recursion is the idiomatic iteration method), it would be better to ask about a problem that is best solved using recursion rather than printing "Hello world" -- perhaps something from Project Euler (http://projecteuler.net/ http://projecteuler.net/).
  • ajitk 14y ago
    On the contrary, wouldn't OP's solution be an example of more generalized implementation of multiplication? I can see that it is similar to (X * 2) where X defines behavior of __mul__. Yes, there is chance that arbitrary objects can provide different semantics for __mul__. It would be true for any language.
• danielroseman 14y ago
  I think a better Python version would be print '\n'.join(['Hello world'] * 100) No need for exec.
  • masklinn 14y ago
    Or just print "Hello, World\n" * 100 No need for join either, and ends with a newline
  • resurge 14y ago
    I wonder why 430gj9j added exec.. print "Hello world\n"*100 Would have worked just fine.
    • lloeki 14y ago
      He abstracted this loop: for i in xrange(100): statement into: exec "statement" * 100 The 'no exec' alternatives propose something not as generic since they can only print something a number of times.
• codeape 14y ago
  Why the exec? print "Hello world\n" * 100
  • kibwen 14y ago
    That was the first thing that popped into my head upon reading the headline, though I abstracted it a bit: def print_many(n): print("hello, world\n" * n) Though the `exec` option given above certainly is... interesting. :)
• TazeTSchnitzel 14y ago
  Or just this: print ('hello, world\n' * 100)[:-1]
• xabi 14y ago
  Perl version: perl -e 'print "Hello world\n" x 100;'