R代码加入else if分支后报错xy.coords长度不同无法生成图形求助

错误原因 #

• 你提供的示例数据中，datas$Numbers取值为c(10,10,10,10.5)，数值10出现了3次，满足else if(any(table(datas$Numbers) >= 3))的判断条件，代码会进入该分支执行。
• 分支内原代码用yz <- unique(datas$Numbers)得到的yz长度为2（包含10、10.5两个值），拼接坐标向量时：
  • x轴向量c(0, datas$Days)长度为5（1个0加4行Days数据）
  • y轴向量c(yz, datas$Numbers)长度为6（2个唯一值加4行Numbers数据）
    二者长度不一致，调用lines()函数时就会抛出'x' and 'y' lengths differ错误。

修复方法 #

将else if分支中yz的取值逻辑修改为提取出现次数≥3的数值，保证y轴拼接后的长度和x轴一致即可。如果业务场景中可能同时存在多个符合条件的数值，取第一个即可。
需要替换的代码行：

# 原错误代码
yz <- unique(datas$Numbers)
# 替换为
yz <- as.numeric(names(which(table(datas$Numbers) >= 3)))[1]

修复后完整可运行代码 #

library(dplyr)
library(lubridate) # 补充加载ymd依赖的包

df1 <- structure(
  list(date1= c("2021-06-28","2021-06-28","2021-06-28","2021-06-28","2021-06-28"),
       date2 = c("2021-06-29","2021-06-29","2021-07-06","2021-07-06","2021-07-06"),
       Category = c("FDE","ABC","FDE","ABC","DDE"),
       Week= c("Tuesday","Tuesday","Tuesday","Tuesday","Tuesday"),
       DR1 = c(4,2,0,3,2),
       DR01 = c(4,1,0,3,2), DR02= c(4,2,0,2,4),DR03= c(9,5,0,7,1),
       DR04 = c(5,4,0,2,1),DR05 = c(5,4,0,4,1),
       DR06 = c(2,4,0,2,4),DR07 = c(2,5,1,4,5),
       DR08 = c(3,4,1,4,4),DR09 = c(2,3,1,4,5),DR10 = c(2,3,1,4,5),DR11 = c(2,3,0,4,5),DR12 = c(2,3,0,4,5)),
  class = "data.frame", row.names = c(NA, -5L))


datas<-structure(list(Category = c("ABC", "ABC", "ABC", "ABC"), 
                      Days = c(41, 42, 43, 44), 
                      Numbers = c(10,10, 10, 10.5)), row.names = c(NA, -4L), class = "data.frame")

f1 <- function(dmda, CategoryChosse) {
  
  plot(Numbers ~ Days,  xlim= c(0,45), ylim= c(0,30),
       xaxs='i',data = datas,main = paste0(dmda, "-", CategoryChosse))
  
  m<-df1 %>%
    group_by(Category,Week) %>%
    summarize(across(starts_with("DR1"), mean), .groups = "drop") # 补充.groups参数避免dplyr提示
  
  m<-subset(m, Week == df1$Week[match(ymd(dmda), ymd(df1$date2))] & Category == CategoryChosse)$DR1
  
  if (nrow(datas)<=2){
    abline(h=m,lwd=2) 
    points(0, m, col = "red", pch = 19, cex = 2, xpd = TRUE)
    text(.1,m+ .5, round(m,1), cex=1.1,pos=4,offset =1,col="black")
  }
  else if(any(table(datas$Numbers) >= 3)){
    yz <- as.numeric(names(which(table(datas$Numbers) >= 3)))[1] # 修改后的yz取值逻辑
    lines(c(0,datas$Days), c(yz, datas$Numbers), lwd = 2)
    points(0, yz, col = "red", pch = 19, cex = 2, xpd = TRUE)
    text(.1,yz+ .5,round(yz,1), cex=1.1,pos=4,offset =1,col="black")
  }
  else{
    mod <- nls(Numbers ~ b1*Days^2+b2,start = list(b1 = 0,b2 = 0),data = datas, algorithm = "port")
    new.data <- data.frame(Days = with(datas, seq(min(Days),max(Days),len = 45)))
    new.data <- rbind(0, new.data)
    lines(new.data$Days,predict(mod,newdata = new.data),lwd=2)
    coef<-coef(mod)[2]
    points(0, coef, col="red",pch=19,cex = 2,xpd=TRUE)
    text(.99,coef + 1,max(0, round(coef,1)), cex=1.1,pos=4,offset =1,col="black")
  }
}
f1("2021-06-29", "ABC")

内容的提问来源于stack exchange，提问作者Antonio