在条形图的背景中添加条形

Question

我在图表背景中添加衰退条时遇到了一些问题。正确的方法是什么？ 我试图为背景定义 geom_rect(.....) 但这没有正常工作。

这是我如何获取数据的代码：

library(quantmod)
library(dplyr)
library(ggplot2)


getSymbols("USPRIV",src="FRED")
getSymbols("USGOVT",src="FRED")

#convert data from quantmod into dataframes
uspriv.df <- data.frame(date= index(USPRIV),USPRIV$USPRIV)
usgovt.df <- data.frame(date= index(USGOVT),USGOVT$USGOVT)

#calculate month-to-month difference
d.uspriv <- dplyr::mutate(uspriv.df[-1,], duspriv = uspriv.df$USPRIV[-1]-uspriv.df$USPRIV[-nrow(uspriv.df)])
d.usgovt <- dplyr::mutate(usgovt.df[-1,], dusgovt = usgovt.df$USGOVT[-1]-usgovt.df$USGOVT[-nrow(usgovt.df)])

df <- dplyr::left_join(d.uspriv, d.usgovt, by = "date")

#shorten dataframe, starting in 2007
df.2007 <- dplyr::filter(df, date >= "2007-01-01") 
df1.2007 <- dplyr::select(df.2007, date, duspriv, dusgovt)

df1 <- melt(df1.2007, id="date")

ggplot(df1, aes(x=date, y=value)) + 
        geom_bar(aes(fill=variable), 
                     stat="identity",
                 position=position_dodge()) +
        scale_fill_brewer(palette="Dark2")

这会生成这个图表here：

包含衰退条的最有效方法是什么？ 这是获取数据的代码

getSymbols("USREC",src="FRED")

usrec.df <- data.frame(date= index(USREC), USREC$USREC)

如果我将衰退数据包含到数据框中然后将其融化，我将如何定义 ggplot 部分？

非常感谢。

Answer 1

这是一个更强大的解决方案。当有多次衰退时它不应该失败（这句话的讽刺......）。感谢用户bergant。 注意：您仍然需要确保在您考虑的时间范围内有匹配的 USREC 数据。 我从1965开始做了一个例子。

library(quantmod)
library(dplyr)
library(reshape2)
library(ggplot2)


getSymbols("USPRIV",src="FRED")
getSymbols("USGOVT",src="FRED")

#convert data from quantmod into dataframes
uspriv.df = data.frame(date= index(USPRIV),USPRIV$USPRIV)
usgovt.df = data.frame(date= index(USGOVT),USGOVT$USGOVT)

#calculate month-to-month difference
d.uspriv = dplyr::mutate(uspriv.df[-1,], duspriv = uspriv.df$USPRIV[-1]-uspriv.df$USPRIV[-nrow(uspriv.df)])
d.usgovt = dplyr::mutate(usgovt.df[-1,], dusgovt = usgovt.df$USGOVT[-1]-usgovt.df$USGOVT[-nrow(usgovt.df)])

df = dplyr::left_join(d.uspriv, d.usgovt, by = "date")

#shorten dataframe, starting in 1965
df.1965 = dplyr::filter(df, date >= "1965-01-01") 
df1.1965 = dplyr::select(df.1965, date, duspriv, dusgovt)

df1 = melt(df1.1965, id="date")


#########
getSymbols("USREC",src="FRED")
usrec = data.frame(date= index(USREC), USREC$USREC)
rownames(usrec) = NULL

new_df = merge(df1, usrec)

##############

# Thanks go out to @bergant for this bit:
dif = diff(new_df$USREC)
new_df$Status = factor(c(0, dif) - 2 * c(dif, 0), levels = -3:3)
levels(new_df$Status) = c(rep(0, 4), "Start", "End", "Start&End")

##############

start_end_dt = data.frame(
            xmin = as.Date(new_df$date[new_df$Status == "Start"])
          , xmax = as.Date(new_df$date[new_df$Status == "End"])
)

##############

剩下的很简单：

ggplot(new_df, aes(x=date, y=value)) + 
  geom_rect(    inherit.aes = FALSE
              , data = start_end_dt
              , aes(xmin = xmin
                  , xmax = xmax
                  , ymin=-Inf
                  , ymax=+Inf)
              , fill='gray'
              , alpha=0.5) +
  geom_bar(aes(fill=variable), 
           stat="identity",
           position=position_dodge()) +
  scale_fill_brewer(palette="Dark2") +   
  theme_bw() + 
  theme( panel.grid.minor = element_blank(), panel.grid.major = element_blank() )