有谁知道为什么我的数据没有图表?
数据帧
univ_apps
----------------------------
timeappreceived chr May_12_2002, March_4_2002
bs_ms_phd factor 1 for bs 2 for ms 3 for phd
appid int rn89 qw23 et43
sample data
--------------
timeappreceived bs_ms_phd appid
Sept_2_1989 1 rn89
Sept_2_1989 2 dq11
Oct_1_2011 1 bg32
ETC
univdata = ggplot(univ_apps,
aes(x= yearappreceived, y= appid, fill=as.factor(bs_ms_phd))) +
geom_area(position="stack")
我是否从命令中遗漏了一些东西?