Change reference level for variable in R -

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i have data set, (call data) variable, color. mode of color numeric , class factor. first, i'm bit confused "numeric" -- when printed out, data color not numeric -- character values, white or blue or black, etc. clarification on appreciated.

further, need write r code return levels of color variable, determine current reference level of variable, , set reference level of variable white. tried using factor, entirely unsuccessful.

thank taking time help.

mode(data$color) "numeric" because r internally stores factors numeric codes (to save space), plus associated vector of labels corresponding code values. when print factor, r automatically substitutes corresponding label each code.

f <- factor(c("orange","banana","apple")) ## [1] orange banana apple  ## levels: apple banana orange str(f) ##  factor w/ 3 levels "apple","banana",..: 3 2 1 c(f)    ## strip attributes numeric vector ## [1] 3 2 1  attributes(f) ## $levels ## [1] "apple"  "banana" "orange" ## $class ## [1] "factor"

... need write r code return levels of color variable ...

levels(data$color)

... determine current reference level of variable,

levels(data$color)[1]

... , set reference level of variable white. 

data$color <- relevel(data$color,"white")

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