sum function

[Ramchandra Apte]

On Friday, 5 October 2012 19:09:15 UTC+5:30, Mike  wrote:
> 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())
> 
> IndexError: list index out of range

the variable "r" is an empty list