r - 底部图例，两行包裹在 r 中的 ggplot2 中

Question

library(ggplot2)
library(scales)
library(reshape2)  

Rdates <- c("2007-01-31","2007-02-28","2007-03-30","2007-04-30","2007-05-31","2007-06-29","2007-07-31","2007-08-31","2007-09-28","2007-10-31")
Rdates <- as.Date(Rdates)
Cnames <- c("Column 1 Really Long","Column 2 Really Long","Column 3 Really Long","Column 4 Really Long","Column 5 Really Long","Column 6 Really Long","Column 7 Really Long","Column 8 Really Long","Column 9 Really Long","Column 10 Really Long")
MAINDF <- data.frame(replicate(10,runif(10,-0.03,0.03)))
rownames(MAINDF) <- Rdates
colnames(MAINDF) <- Cnames
CUSTOMpalette <- c("#1a2ffa", "#0d177d", "#1a9ffa", "#fa751a", "#4b8e12", "#6fd21b", "#fae51a", "#c3b104", "#f5df05", "#dcc805")
MAINDF[,"dates"] <- Rdates

MAINDF <- melt(MAINDF,id.vars="dates")

gg <- ggplot(MAINDF, aes(x = dates, y = value, fill = variable))
gg <- gg + geom_bar(stat = "identity")
gg <- gg + scale_x_date(breaks = "3 months", labels=date_format("%b%y"),limits=c(min(as.Date(MAINDF$dates)),max(as.Date(MAINDF$dates))))
gg <- gg + theme(
  axis.text.x= element_text(color="black",angle=45, size=10, vjust=0.5),
  axis.text.y= element_text(color="black", size=12, vjust=0.5),
  axis.title.y = element_text(color="black",size=12, vjust=0.5),
  plot.title = element_text(color="black",face="bold",size=14, hjust=0.5,vjust=1),
  panel.background = element_blank(),
  panel.border = element_rect(linetype = "solid", colour = "black",fill=NA),
  legend.position="bottom",
  legend.title = element_blank(),
  legend.key = element_rect(fill="white"), legend.background = element_rect(fill=NA)
)
gg <- gg + xlab("") + ylab("Monthly Returns") 
gg <- gg + ggtitle("Contribution by Strategy")
gg <- gg + scale_y_continuous(labels = percent_format())
gg <- gg + scale_fill_manual(values=CUSTOMpalette)
gg

目前有一个 ggplot2 堆叠条形图设置。现在一切正常，除了我对图例有疑问。我已经把它放在底部了，但有 10 件元素，所以有些被切断了(不适合)。我尝试了 guides(fill=guide_legend(nrow=2)) 但这会将标签置于不同的顺序(我想获取前 5 个，然后获取下面的后 5 个。有什么建议吗？

Answer 1

你们真的很亲密。最后尝试一下:

gg+guides(fill=guide_legend(nrow=2,byrow=TRUE))