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Math Forum » Discussions » Software » comp.soft-sys.matlab

Topic: Is there a better way to count number of occurances of string when grouping?
Replies: 6   Last Post: Mar 20, 2012 6:11 PM

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Tom Lane

Posts: 834
Registered: 12/7/04
Re: Is there a better way to count number of occurances of string when grouping?
Posted: Mar 20, 2012 6:11 PM
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> I have a dataset svdatm with columns:
>
> % dnum (datenum)
> % symid (symbol id - a cell array)
>
> I would like to find the count or number of elements (i.e., symid)
> that occur each day.

In addition to the other suggestions, consider trying

crosstab(svdatm.dnum, svdatm.symid)

I don't know if it would be any faster, and it might require too much memory
if there are lots of unique symid values, but it's a thought.

-- Tom




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