[R] A file manipulation question

Liaw, Andy
2004-03-04T03:46:32Z

Say your data frame is `dat'.  Try:

    tapply(dat$Contract, dat$ID, max)

(The output is not a data frame, but that shouldn't be a problem...)

HTH,
Andy


> From: Greg Blevins
>
> Hello R experts,
>
> The following problem outstrips my current programming knowledge.
>
> I have a dataframe with two fields that looks like the following:
>
> ID     Contract
>
> 01     1
>
> 01     1
>
> 02     2
>
> 02     3
>
> 02     1
>
> 03     2
>
> 03     2
>
> 03     2
>
> 03     1
>
> 03     1
>
> 03     1
>
> etc...
>
> I would like to end up with a dataframe with one row per ID
> where the value in the contract field would be the highest
> value recorded for a single ID. As you can see above, the
> number of IDs varies irregularly.  Given the above, the new
> file would look like the following:
>
> ID     Contract
>
> 01     1
>
> 02     3
>
> 03     2
>
> Thanks in advance for your suggestions.
>
> Gregory L. Blevins The Market Solustions Group, Partner
>
>
>
> 	[[alternative HTML version deleted]]
>
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