On 3/30/2017 4:57 PM, Boylan, Ross wrote:
https://docs.python.org/3/reference/expressions.html#displays-for-lists-sets-and-dictionaries
describes the syntax for comprehensions as
comprehension ::= expression comp_for
comp_for ::= [ASYNC] "for" target_list "in" or_test [comp_iter]
comp_iter ::= comp_for | comp_if
comp_if ::= "if" expression_nocond [comp_iter]
Is the comp_for missing an argument after "in"?
The or_test *is* the 'argument'.
One has to follow the definition of or_test and its components,
> but I can't find anything that results to a single variable
> or expression.
An or_test *is* a single expression. Like all python expressions, it
evaluates to a python object. In this case, the object is passed to
iter() and so the object must be an iterable.
>>> a, b = None, range(3)
>>> a or b
range(0, 3)
>>> for i in a or b: print(i)
0
1
2
--
Terry Jan Reedy
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