; Íâ"Ic@sAdZied6Zdd„ZedkoeddƒndS(uå Unpack tuple >>> t = (1, 2, 3) >>> a, *b, c = t >>> a == 1 and b == [2] and c == 3 True Unpack list >>> l = [4, 5, 6] >>> a, *b = l >>> a == 4 and b == [5, 6] True Unpack implied tuple >>> *a, = 7, 8, 9 >>> a == [7, 8, 9] True Unpack string... fun! >>> a, *b = 'one' >>> a == 'o' and b == ['n', 'e'] True Unpack long sequence >>> a, b, c, *d, e, f, g = range(10) >>> (a, b, c, d, e, f, g) == (0, 1, 2, [3, 4, 5, 6], 7, 8, 9) True Unpack short sequence >>> a, *b, c = (1, 2) >>> a == 1 and c == 2 and b == [] True Unpack generic sequence >>> class Seq: ... def __getitem__(self, i): ... if i >= 0 and i < 3: return i ... raise IndexError ... >>> a, *b = Seq() >>> a == 0 and b == [1, 2] True Unpack in for statement >>> for a, *b, c in [(1,2,3), (4,5,6,7)]: ... print(a, b, c) ... 1 [2] 3 4 [5, 6] 7 Unpack in list >>> [a, *b, c] = range(5) >>> a == 0 and b == [1, 2, 3] and c == 4 True Multiple targets >>> a, *b, c = *d, e = range(5) >>> a == 0 and b == [1, 2, 3] and c == 4 and d == [0, 1, 2, 3] and e == 4 True Now for some failures Unpacking non-sequence >>> a, *b = 7 Traceback (most recent call last): ... TypeError: 'int' object is not iterable Unpacking sequence too short >>> a, *b, c, d, e = Seq() Traceback (most recent call last): ... ValueError: need more than 3 values to unpack Unpacking a sequence where the test for too long raises a different kind of error >>> class BozoError(Exception): ... pass ... >>> class BadSeq: ... def __getitem__(self, i): ... if i >= 0 and i < 3: ... return i ... elif i == 3: ... raise BozoError ... else: ... raise IndexError ... Trigger code while not expecting an IndexError (unpack sequence too long, wrong error) >>> a, *b, c, d, e = BadSeq() Traceback (most recent call last): ... test.test_unpack_ex.BozoError Now some general starred expressions (all fail). >>> a, *b, c, *d, e = range(10) # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: two starred expressions in assignment >>> [*b, *c] = range(10) # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: two starred expressions in assignment >>> *a = range(10) # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: starred assignment target must be in a list or tuple >>> *a # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: can use starred expression only as assignment target >>> *1 # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: can use starred expression only as assignment target >>> x = *a # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: can use starred expression only as assignment target Some size constraints (all fail.) >>> s = ", ".join("a%d" % i for i in range(1<<8)) + ", *rest = range(1<<8 + 1)" >>> compile(s, 'test', 'exec') # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: too many expressions in star-unpacking assignment >>> s = ", ".join("a%d" % i for i in range(1<<8 + 1)) + ", *rest = range(1<<8 + 2)" >>> compile(s, 'test', 'exec') # doctest:+ELLIPSIS Traceback (most recent call last): ... SyntaxError: too many expressions in star-unpacking assignment (there is an additional limit, on the number of expressions after the '*rest', but it's 1<<24 and testing it takes too much memory.) udoctestscCs@ddl}ddlm}ddlm}|j||ƒdS(Ni(usupport(utest_unpack_ex(usysutestusupportutest_unpack_exu run_doctest(uverboseusysusupportutest_unpack_ex((u0/mit/python/lib/python3.0/test/test_unpack_ex.pyu test_main§s u__main__uverboseNFT(udoctestsu__test__uFalseu test_mainu__name__uTrue(((u0/mit/python/lib/python3.0/test/test_unpack_ex.pyu£s