r - How to convert character/factor to integer? -

i know has been asked quite frequently. however, applying previous advice i'm still confused 2 things.

1. how convert multinomial values integers?

2. how integer factor/character after analysis?

     library(car)    data(prestige)   view(prestige)   # here convert directly character seems quite useless   prestige$type<-as.numeric(levels(prestige$type))   # here generate factors   prestige$type<-as.factor(prestige$type)   # , try convert afterwards. doesnt work either   prestige$type<-as.numeric(levels(prestige$type)) 

basically, extract 3 levels in type without renaming manually.

a vector class factor has attributes called levels. levels function acts on attributes , not on vector itself.

library(car) data(prestige)  length(prestige$type) # 102  levels(prestige$type) # notice has length 3. 

if want numeric values vector, use

as.numeric(prestige$type) 

what bc not 1, prof 2, , wc 3.

if need reconstitute factor, use

factor(prestige$type, 1:3, c("bc", "prof", "wc")) 

but general rule, it's better not alter factors unless need alter categories. if need numerical codes under data, make new variable

prestige$type_numeric <- as.numeric(prestige$type)