Sum by categorical variable
Hi
On 6 May 2003 at 16:53, De Amicis Fabrizio (G.I.T.) wrote:
Another easy(/stupid) question: with the following command j2<-xf1[1:10,"V4"] I have
j2
[1] CHROMOLI LINEAGERMAI RINALDI GIUNTIMA AUTOSTELLA [6] CAIZZONE CENTRO B PEL E C SNC CONSORZI MAN NORD PDM 1304 Levels: MACHIAVELLI Snc MENARINI MANUFACTURERS LOGISTICS SERVICES ... ZUCCHERIFICIO DEL MOLISE Why j2 has 1304 Levels (I know that xf has 1304 rows)? How can I obtain a vector of 10 elements?
You actually have got first 10 elements of variable "V4" in j2 see length(j2), but as it is a factor the level attribute has retained an information about all different levels of "V4" which I presume is 1304. To get rid of these levels just use factor(j2)
Thank you
--------------------------------------------------------------- Fabrizio De Amicis IT Department Generali Information Technologies - (GIT) Centro Galleria 2, Via Cantonale CH - 6928 Manno - Switzerland Tel +41 91 806 6220 Fax +41 91 806 6298 E-mail: fabrizio.deamicis at git.generali.ch
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