facet_wrap中按组的均值和观察值 数据集的简要示例：当前图输出：

如何解决facet_wrap中按组的均值和观察值 数据集的简要示例：当前图输出：

我阅读了数十篇有关如何在每个facet_wrap中添加标签的帖子，但我希望在这里有所帮助，因为我坚持添加均值（λ）和观测值数量（ k ）。我使用了大部分post，但在以下各项方面感到困惑：

1. 将正确的均值和观察值的数量按组添加到方面
2. 将均值取整为两位数
3. 将“均值”标签更改为正确的希腊字母lambda-Unicode（u + 03BB）

df_dztpois <- subset(df_full,select=c("PIA_ITEM","PIA_TYPE","DELY_QTY_WINS","DELY_QTY_DZTPOIS"))

df_dztpois_summary = df_dztpois %>% group_by(PIA_ITEM) %>%
  summarize(count = length(DELY_QTY_WINS),mean = mean(DELY_QTY_WINS)) %>%
  mutate(lab = paste("count = ",count,"\nmean = ",mean))

p <- ggplot(data = df_dztpois,aes(x=DELY_QTY_WINS))
p <- p + geom_line(aes(y=DELY_QTY_DZTPOIS))
p <- p + facet_wrap( ~ PIA_TYPE,nrow=3,scales = "free")
p <- p + xlab("Observation") + ylab("Probability")
p <- p + theme(
  legend.position = "bottom",legend.text = element_text(size = 12),strip.text.x = element_text(size = 12))
p <- p + labs(title = "Zero-truncated Poisson distribution of order quantity",subtitle = "Grouped by product (PIA_TYPE)",caption = "Data source: df_dztpois$DELY_QTY_WINS and df_full$DELY_QTY_DZTPOIS")
p <- p + geom_text(data = df_dztpois_summary,aes(label = lab),x=Inf,y=Inf,hjust=1,vjust=1.2)
p

数据集的简要示例：

> dput(df_dztpois[1:10,])
structure(list(PIA_ITEM = structure(c(2L,2L,2L),.Label = c("RX20 1.5t Type 6209-10","RX20 1.6t Type 6211","RX20 1.6t Type 6221","RX20 1.8t Type 6213","RX20 2.0t Type 6215","RX20 2.0t Type 6225","RX20 2.0t Type 6230"),class = "factor"),PIA_TYPE = c("6211","6211","6211"),DELY_QTY_WINS = c(75,62,57,67,53,70,60),DELY_QTY_DZTPOIS = c(1.09669678480388e-08,3.8744657910606e-05,0.000448728658516301,2.24150656988175e-06,0.0023318386482722,3.38775858809732e-07,0.000108487832825478
    )),row.names = c(NA,10L),class = "data.frame")

> str(df_dztpois)
'data.frame':   959 obs. of  4 variables:
 $ PIA_ITEM        : Factor w/ 7 levels "RX20 1.5t Type 6209-10",..: 2 2 2 2 2 2 2 2 2 2 ...
 $ PIA_TYPE        : chr  "6211" "6211" "6211" "6211" ...
 $ DELY_QTY_WINS   : num  75 62 57 57 67 57 53 70 70 60 ...
 $ DELY_QTY_DZTPOIS: num  1.10e-08 3.87e-05 4.49e-04 4.49e-04 2.24e-06 ...

当前图输出：

解决方法

您的代码有一个问题：

• 您用PIA_TYPE进行了构面，但摘要df按PIA_ITEM分组了

我不确定这是否是根本原因，因为在您的示例数据中，PIA_TYPE和PIA_ITEM相同，因此我将PIA_TYPE更改为2个不同的级别

创建摘要df时，您可以使用n()来计算观察值的数量，使用round来获取正确的数字并将lambda表示为\U03BB。

df_dztpois <- structure(list(PIA_ITEM = structure(c(2L,2L,2L),.Label = c("RX20 1.5t Type 6209-10","RX20 1.6t Type 6211","RX20 1.6t Type 6221","RX20 1.8t Type 6213","RX20 2.0t Type 6215","RX20 2.0t Type 6225","RX20 2.0t Type 6230"),class = "factor"),PIA_TYPE = c("6211","6211","6212","6212"),DELY_QTY_WINS = c(75,62,57,67,53,70,60),DELY_QTY_DZTPOIS = c(1.09669678480388e-08,3.8744657910606e-05,0.000448728658516301,2.24150656988175e-06,0.0023318386482722,3.38775858809732e-07,0.000108487832825478
                                                                                            )),row.names = c(NA,10L),class = "data.frame")

library(ggplot2)
library(dplyr)

df_dztpois_summary <- df_dztpois %>%
  group_by(PIA_TYPE) %>%
  summarize(count = n(),mean = mean(DELY_QTY_WINS)) %>%
  mutate(lab = paste("count = ",count,"\n\U03BB = ",round(mean,digits = 2)))

p <- ggplot(data = df_dztpois,aes(x=DELY_QTY_WINS))
p <- p + geom_line(aes(y=DELY_QTY_DZTPOIS))
p <- p + facet_wrap( ~ PIA_TYPE,nrow=3,scales = "free")
p <- p + xlab("Observation") + ylab("Probability")
p <- p + theme(
  legend.position = "bottom",legend.text = element_text(size = 12),strip.text.x = element_text(size = 12))
p <- p + labs(title = "Zero-truncated Poisson distribution of order quantity",subtitle = "Grouped by product (PIA_TYPE)",caption = "Data source: df_dztpois$DELY_QTY_WINS and df_full$DELY_QTY_DZTPOIS")
p <- p + geom_text(data = df_dztpois_summary,aes(label = lab),x=Inf,y=Inf,hjust=1,vjust=1.2)
p