sum function

[Mike]

On Friday, October 5, 2012 9:41:44 AM UTC-4, Ramchandra Apte wrote:
> On Friday, 5 October 2012 19:09:15 UTC+5:30, Mike  wrote:
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> > On Thursday, October 4, 2012 4:52:50 PM UTC-4, Mike wrote:
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> > > Hi All,
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> > > I am new to python and am getting the data from hbase. 
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> > > I am trying to do sum on the column as below
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> > > scanner = client.scannerOpenWithStop("tab", "10", "1000", ["cf:col1"])
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> > > total = 0.0
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> > > r = client.scannerGet(scanner)
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> > > while r:
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> > >   for k in (r[0].columns):
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> > >     total += float(r[0].columns[k].value)
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> > >   r = client.scannerGet(scanner)
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> > > print total
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> > > Do you know of better (faster) way to do sum?
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> > > Any thoughts please?
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> > > Thanks
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> > Sorry about that. Here you go
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> > Traceback (most recent call last):
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> >   File "test.py", line 17, in <module>
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> >     total = sum(float(col.value) for r in iter(next_r, None) for col in r[0].columns.itervalues())
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> >   File "test.py", line 17, in <genexpr>
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> >     total = sum(float(col.value) for r in iter(next_r, None) for col in r[0].columns.itervalues())
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> > IndexError: list index out of range
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> the variable "r" is an empty list

Here is the actual code.

scanner = client.scannerOpenWithStop("tab", "10", "1000", ["cf:col1"]) 
next_r = functools.partial(client.scannerGet, scanner)
total = sum(float(col.value) for r in iter(next_r, None) for col in r[0].columns.itervalues())


Scanner does have rows.

Are we missing something please?

Thanks