Am 10.01.2012 12:37 schrieb Νικόλαος Κούρας:
So that means that
for host, hits, agent, date in dataset:
is:
for host, hits, agent, date in (foo,7,IE6,1/1/11)
and then:
for host, hits, agent, date in (bar,42,Firefox,2/2/10)
and then:
for host, hits, agent, date in (baz,4,Chrome,3/3/09)
No.
As said, dataset is the whole result set. For now, you can see it as a
list of all rows (which you get if you do l=list(dataset)).
Let's assume you have your data in a list now, which is equivalent
concerning the iteration.
Then you have something like
dataset = [
('foo',7,'IE6','1/1/11'),
('bar',42,'Firefox','2/2/10'),
('baz',4,'Chrome','3/3/09')
]
Doing
for row in dataset: print row
is equivalent to
row = ('foo',7,'IE6','1/1/11')
print row
row = ('bar',42,'Firefox','2/2/10')
print row
row = ('baz',4,'Chrome','3/3/09')
print row
Doing
for a, b, c, d in dataset:
do_funny_stuff(a, d, c, b)
is
a, b, c, d = ('foo',7,'IE6','1/1/11');
# which is the same as
# a = 'foo'; b = 7; c = 'IE6'; d = '1/1/11';
do_funny_stuff(a, d, c, b)
a, b, c, d = ('bar',42,'Firefox','2/2/10')
do_funny_stuff(a, d, c, b)
a, b, c, d = ('baz',4,'Chrome','3/3/09')
do_funny_stuff(a, d, c, b)
The "body" of the for suite is executed once for each element.
You have read already
http://docs.python.org/tutorial/controlflow.html#for-statements
http://docs.python.org/library/stdtypes.html#iterator-types
?
Thomas
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