Sum by categorical variable

Hello,

Because j2 is interpreted as a factor.
To get your vector of just 10 elements use as.vector(j2).

Regards,
Carlos.


-----Mensaje original-----
De: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] En nombre de De Amicis
Fabrizio (G.I.T.)
Enviado el: martes, 06 de mayo de 2003 16:54
Para: 'r-help at lists.R-project.org'
Asunto: [R] FW: Sum by categorical variable



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?

Thank you

 

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