I have a list named d like this:
V1 is an integer set from 0 - 50
V2 is a real set from 1500 - 1800
V3 is an integer set from 1 - 50
In total, the list contains 5100 objects
Now I would like to plot the histogram of V2, with V1 = a certain number (0, 1 or 10, etc.)
I tried different ways:
factor(d$V1)
qplot(V2, data=d, V1 = 1) --> not successful
d.subset <- subset(d, d$V1 = 1) --> not successful
I really get crazy with this. Check the characteristics of d$V1 but found nothing strange. Anyone could help me out?
is.factor(d$V1)
[1] TRUE
str(d$V1) Factor w/ 51 levels "1","2","3","4",..: 1 2 3 4 5 6 7 8 9 10 ...
levels(d$V1)
[1] "1" "2" "3" "4" "5" "6" "7" "8" "9" "10" "11" "12" "13" "14" "15" "16" "17" "18" "19"
[20] "20" "21" "22" "23" "24" "25" "26" "27" "28" "29" "30" "31" "32" "33" "34" "35" "36" "37""38"
[39] "39" "40" "41" "42" "43" "44" "45" "46" "47" "48" "49" "50" "51"
Change the line:
d.subset <- subset(d, d$V1 = 1)
to
d.subset <- subset(d, V1 == 1)
Notice the double equals (==) to denote the logical operator. = is used for assignment and doesn't subset the data frame.
Finally, you might mean to put the 1 in quotes if you want to get the "1" level of the factor (which might not be the same as the numeric 1).
d.subset <- subset(d, V1 == "1")