Kent Johnson wrote:
On Thu, Nov 13, 2008 at 10:01 AM, A.T.Hofkamp <[EMAIL PROTECTED]> wrote:
d3 = dict(( (rv, dict.fromkeys(c)) for rv in r ))
You don't need the double parentheses, this works just as well:
d3 = dict( (rv, dict.fromkeys(c)) for rv in r )
A generator expression just has to be in parentheses, it's OK if the
parens also have other meaning syntactically; in this case indicating
a function call.
... as long as it's the only argument to the function call.
Otherwise you'll get a syntax error[*]. But you'll find this
out pretty quickly when you try anyway!
I realise that, strictly speaking, Kent's explanation already says this
if you read "in parentheses" as meaning "the only thing in paren..."
but just in case :)
TJG
<dump>
sum (x*x for x in range (10), 5)
File "<stdin>", line 1
SyntaxError: Generator expression must be parenthesized if not sole argument
</dump>
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