r - ggplot2:热图绘图，geom_text 仅在选定单元格中放置

Question

我正在使用热图来跟踪我的实验中的损耗，我想在前两列中专门打印一些日期信息，但由于某种原因，ggplot2 不会接受那么多缺失的观察结果。

这就是我的情节目前的样子(许多日期的方式)。

谁能告诉我如何将 geom_text 限制为仅前两列？

示例代码见blow。

require(ggplot2)
require(plyr)
require(reshape)

# create sample data
set.seed(666)
dfn <- data.frame(
Referral  = seq(as.Date("2007-01-15"), len= 26, by="23 day"),
VISIT01  = seq(as.Date("2008-06-15"), len= 24, by="15 day")[sample(30, 26)],
VISIT02  = seq(as.Date("2008-12-15"), len= 24, by="15 day")[sample(30, 26)],
VISIT03  = seq(as.Date("2009-01-01"), len= 24, by="15 day")[sample(30, 26)],
VISIT04  = seq(as.Date("2009-03-30"), len= 24, by="60 day")[sample(30, 26)],
VISIT05  = seq(as.Date("2010-11-30"), len= 24, by="6 day")[sample(30, 26)],
VISIT06  = seq(as.Date("2011-01-30"), len= 24, by="6 day")[sample(30, 26)],
Discharge = seq(as.Date("2012-03-30"), len= 24, by="30 day")[sample(30, 26)],
Patient  = factor(1:26, labels = LETTERS),
openCase  = rep(0:1, 100)[sample(100, 26)])

 # set today's data for cases that do not have an Discharge date
 dfn$Discharge[ is.na(dfn$Discharge) ] <- as.Date("2014-01-30")

 mdfn <- melt(dfn, id=c('Patient', 'openCase'), variable_name = "Visit")
 names(mdfn)[4] <- 'Year'

 # order data in mdfn by 'Referral' in dfn
 mdfn$Patient <- factor(mdfn$Patient,levels = (dfn$Patient[order(dfn$Referral)]),
 ordered = TRUE)

mdfn$Year2 <- ifelse(mdfn$Year != 0, 1, 0)
mdfn$Year2[ is.na(mdfn$Year) ] <- 0

mdfn$FWrap <- 'Core Measures'
mdfn$FWrap[mdfn$Visit == 'Referral'] <- 'Referral'
mdfn$FWrap[mdfn$Visit == 'VISIT05' | mdfn$Visit == 'VISIT06'] <- 'Optional Measures'
mdfn$FWrap[mdfn$Visit == 'Discharge'] <- 'Discharge'
mdfn$FWrap <- ordered(mdfn$FWrap, levels = c('Referral', 'Core Measures', 'Optional Measures', 'Discharge'))

base_size <- 9
m2 <- ggplot(mdfn, aes(Visit, Patient)) + 
geom_tile(aes(fill = Year2), colour = "gray") +
scale_fill_gradient(low = "white", high = "steelblue")
m2 + theme_grey(base_size = base_size) + labs(x = "", y = "") +
scale_x_discrete(expand = c    (0, 0)) + scale_y_discrete(expand = c(0, 0)) + 
opts(legend.position = "none", axis.ticks = theme_blank(), 
axis.text.x = theme_text(size = base_size * 0.8, angle = 330, hjust = 0,
colour = "grey50")) + facet_grid(~ FWrap, scales = "free", space="free") + 
geom_text(aes    (label=format(Year, "%b. %d, %Y")), size=3, colour='white')

# this is how I thought I could solve it.
mdfn$Yearlabel <- mdfn$Year
mdfn$Yearlabel[mdfn$Visit != 'Referral' & mdfn$Visit != 'VISIT01'] <- NA
# mdfn[,c(4,5,7,3)]

m2 <- ggplot(mdfn, aes(Visit, Patient)) + 
geom_tile(aes(fill = Year2), colour = "gray") +
scale_fill_gradient(low = "white", high = "steelblue")
m2 + theme_grey(base_size = base_size) + labs(x = "", y = "") +
scale_x_discrete(expand = c    (0, 0)) + scale_y_discrete(expand = c(0, 0)) + 
opts(legend.position = "none", axis.ticks = theme_blank(), 
axis.text.x = theme_text(size = base_size * 0.8, angle = 330, hjust = 0,
colour = "grey50")) + facet_grid(~ FWrap, scales = "free", space="free") + 
geom_text(aes    (label=format(Yearlabel, "%b. %d, %Y")), size=3, colour='white')

Answer 1

尝试这个，

p = ggplot(mdfn, aes(Visit, Patient)) + 
  geom_tile(aes(fill = Year2), colour = "gray") +
  scale_fill_gradient(low = "white", high = "steelblue") + 
  theme_grey(base_size = base_size) + 
  labs(x = "", y = "") +
  scale_x_discrete(expand = c(0, 0)) + 
  scale_y_discrete(expand = c(0, 0)) + 
  opts(legend.position = "none", axis.ticks = theme_blank(), 
       axis.text.x = theme_text(size = base_size * 0.8, angle = 330,
         hjust = 0, colour = "grey50")) + 
  facet_grid(~ FWrap, scales = "free", space="free") 

s = subset(mdfn, Visit %in% c("Referral","VISIT01"))
p + geom_text(aes(label=format(Year, "%b. %d, %Y")), data = s, 
              size=3, colour = 'white')