diff options
| -rw-r--r-- | r.html.markdown | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/r.html.markdown b/r.html.markdown index 7cb56fd7..c555d748 100644 --- a/r.html.markdown +++ b/r.html.markdown @@ -179,7 +179,7 @@ c(3,3,3,2,2,1) # 3 3 3 2 2 1 # You can also have infinitely large or small numbers class(Inf) # "numeric" class(-Inf) # "numeric" -# You might use "Inf", for example, in integrate( dnorm(x), 3, Inf); +# You might use "Inf", for example, in integrate(dnorm, 3, Inf); # this obviates Z-score tables. # BASIC ARITHMETIC @@ -236,11 +236,12 @@ c('Z', 'o', 'r', 'r', 'o') == "Z" # TRUE FALSE FALSE FALSE FALSE # FACTORS # The factor class is for categorical data # Factors can be ordered (like childrens' grade levels) or unordered (like gender) -factor(c("female", "female", "male", "NA", "female")) -# female female male NA female -# Levels: female male NA +factor(c("female", "female", "male", NA, "female")) +# female female male <NA> female +# Levels: female male # The "levels" are the values the categorical data can take -levels(factor(c("male", "male", "female", "NA", "female"))) # "female" "male" "NA" +# Note that missing data does not enter the levels +levels(factor(c("male", "male", "female", NA, "female"))) # "female" "male" # If a factor vector has length 1, its levels will have length 1, too length(factor("male")) # 1 length(levels(factor("male"))) # 1 |