python - Is it pythonic for a function to return multiple values? -

in python, can have function return multiple values. here's contrived example:

def divide(x, y):     quotient = x/y     remainder = x % y     return quotient, remainder    (q, r) = divide(22, 7) 

this seems useful, looks can abused ("well..function x computes need intermediate value. let's have x return value also").

when should draw line , define different method?

absolutely (for example provided).

tuples first class citizens in python

there builtin function divmod() that.

q, r = divmod(x, y) # ((x - x%y)/y, x%y) invariant: div*y + mod == x 

there other examples: zip, enumerate, dict.items.

for i, e in enumerate([1, 3, 3]):     print "index=%d, element=%s" % (i, e)  # reverse keys , values in dictionary d = dict((v, k) k, v in adict.items()) # or  d = dict(zip(adict.values(), adict.keys())) 

btw, parentheses not necessary of time. citation python library reference:

tuples constructed comma operator (not within square brackets), or without enclosing parentheses, empty tuple must have enclosing parentheses, such a, b, c or (). single item tuple must have trailing comma, such (d,).

functions should serve single purpose

therefore should return single object. in case object tuple. consider tuple ad-hoc compound data structure. there languages every single function returns multiple values (list in lisp).

sometimes sufficient return (x, y) instead of point(x, y).

named tuples

with introduction of named tuples in python 2.6 preferable in many cases return named tuples instead of plain tuples.

>>> import collections >>> point = collections.namedtuple('point', 'x y') >>> x, y = point(0, 1) >>> p = point(x, y) >>> x, y, p (0, 1, point(x=0, y=1)) >>> p.x, p.y, p[0], p[1] (0, 1, 0, 1) >>> in p: ...   print(i) ... 0 1