[R] Re: how to add a column with string values to a data frame while still converting them to factors

[avneet singh]

i got the first part:

agm.data$ProdCategory=as.factor(agm.data$ProdCategory)

the second i am still struggling with


On 4/26/05, avneet singh <avneet.chugh at gmail.com> wrote:
> I have 2 questions. In essence i am trying to create product
> categories based on product description and have it as an additional
> column of my dataframe. some products dont fit any category and i need
> a list of them. i am having some trouble in this simple (for most)
> task.
> Could you please provide suggestions. Thank you.
> 
> avneet
> 
> Question 1)
> 
> I have a data frame
> 
> >agm.data=read.xls("agm.xls")
> 
> i add a column to it by this and similar statements
> >agm.data$ProdCategory[agm.data$Product.Description=="PGX"|agm.data$Product.Description=="PGW"|agm.data$Product.Description=="PS"|agm.data$Product.Description=="PSX"]="Molded
> Graphite"
> 
> if i do
> >agm.data$ProdCategory
> 
> i get:
> 
>   [1] "Extruded Graphite"   "Molded Graphite"     "Molded Graphite"
>    [4] "Extruded Graphite"   "Extruded Graphite"   NA
>    [7] "Molded Graphite"     "Extruded Graphite"   "Extruded Graphite"
>   [10] "Extruded Graphite"   "Extruded Graphite"   "Extruded Graphite"
>   [13] "Extruded Graphite"   "Porous"              "Iso-Molded Graphite"
> .
> .
> .
> .
> .
> [1222] "Extruded Graphite"   "Molded Graphite"     "Extruded Graphite"
> [1225] "Extruded Graphite"   "Extruded Graphite"   NA
> [1228] "Iso-Molded Graphite" "Extruded Graphite"   NA
> 
> if i check the class, i get
> >is(agm.data$ProdC)
> [1] "character" "vector"
> 
> i want this to have..
> [1] "factor"   "oldClass"
> 
> ..like other columns have
> 
> Question 2)some values of agm.data$ProdCategory are NA. i want to find
> corresponding values of agm.data$Product.Description so i give the
> following command
> >agm.data$Product.Description[agm.data$ProdCategory=="NA"]
> 
> i get:
> 
> [1] <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA>
> <NA> <NA> <NA>
>  [17] <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA>
> <NA> <NA> <NA>
> .
> .
> .
> .
> .
> .
> [257] <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA>
> <NA> <NA> <NA>
> [273] <NA> <NA> <NA> <NA> <NA>
> 165 Levels:  1.563x24 10x50x60 61x1.25 6x72 890S 8x6 9x7; 10x1.5 AGR ... YBDXX88
> 
> --
> God created man because he was disappointed over the apes. After that he has
> given up any further experiments ~Mark Twain
> 


-- 
God created man because he was disappointed over the apes. After that he has
given up any further experiments ~Mark Twain