R软件绘图报错调整：df2数据集无法生成图形问题如何解决

问题原因 #

df2的数值列命名格式与df1不同：

• df1的数值列格式为DRxx（xx为数字，如DR01）
• df2的数值列格式为DRxx_DRxx_PV（如DR01_DR01_PV）

你原代码中pivot_longer的正则DR(.+)会抓取DR后的所有内容，得到01_DR01_PV这类无法转换为数字的字符串，执行as.numeric(name)时就会生成NA，导致后续绘图失败。

解决方法 #

仅需修改pivot_longer的names_pattern参数，仅匹配DR后紧跟的数字即可：

library(dplyr)
library(lubridate)
library(tidyverse)

df2 <- structure(
  list(date1 = c("2021-06-28","2021-06-28","2021-06-28","2021-06-28","2021-06-28",
                 "2021-06-28","2021-06-28","2021-06-28"),
       date2 = c("2021-04-02","2021-04-03","2021-04-08","2021-04-09","2021-04-10","2021-07-01","2021-07-02","2021-07-03"),
       Week= c("Friday","Saturday","Thursday","Friday","Saturday","Thursday","Friday","Monday"),
       DR01_DR01_PV = c(4,1,4,3,3,4,3,6), DR02_DR02_PV= c(4,2,6,7,3,2,7,4),DR03_DR03_PV= c(9,5,4,3,3,2,1,5), DR04_DR04_PV = c(5,4,3,3,6,2,1,9),DR05_DR05_PV = c(5,4,5,3,6,2,1,9),
       DR06_DR06_PV = c(2,4,3,3,5,6,7,8),DR07_DR07_PV = c(2,5,4,4,9,4,7,8)),
  class = "data.frame", row.names = c(NA, -8L))

# 修正后的绘图代码
dmda<-"2021-07-01"

datas<-df2 %>%
  filter(date2 == ymd(dmda)) %>%
  summarize(across(starts_with("DR"), sum)) %>%
  # 仅提取DR后的数字部分
  pivot_longer(everything(), names_pattern = "DR(\\d+).+", values_to = "val") %>%
  mutate(name = as.numeric(name))
colnames(datas)<-c("Days","Numbers")

attach(datas)
plot(Numbers ~ Days, ylim=c(0,20))

model <- nls(Numbers ~ b1*Days^2+b2,start = list(b1 = 47,b2 = 0))

new.data <- data.frame(Days = seq(min(Days),max(Days),len = 45))
lines(new.data$Days,predict(model,newdata = new.data))

修改后即可正常生成和df1效果一致的图形。

内容的提问来源于stack exchange，提问作者user16774617