R语言如何识别数据框全0 DR列并在计算datas时排除

你可以通过dplyr的select() + where()组合实现自动剔除全0 DR列的需求，修改后的完整代码如下：

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

df1 <- 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 = c(4,1,4,3,3,4,3,6), DR02= c(4,2,6,7,3,2,7,4),DR03= c(9,5,4,3,3,2,1,5),
       DR04 = c(5,4,3,3,6,2,1,9),DR05 = c(5,4,5,3,6,2,1,9),
       DR06 = c(2,4,3,3,5,6,7,8),DR07 = c(2,5,4,4,9,4,7,8),
       DR08 = c(0,0,0,1,2,0,0,0),DR09 = c(0,0,0,0,0,0,0,0),DR010 = c(0,0,0,0,0,0,0,0),DR011 = c(0,4,0,0,0,0,0,0), DR012 = c(0,0,0,0,0,0,0,0)),
  class = "data.frame", row.names = c(NA, -8L))

# 新增：自动剔除所有取值全为0的DR开头列
df1 <- df1 %>% 
  select(-where(~ all(.x == 0) & grepl("^DR", cur_column())))

#Generate graph
dmda<-"2021-07-01"
datas<-df1 %>%
  filter(date2 == ymd(dmda)) %>%
  summarize(across(starts_with("DR"), sum)) %>%
  pivot_longer(everything(), names_pattern = "DR(.+)", 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))

代码说明 #

• 新增的预处理逻辑会遍历所有列，仅剔除列名以DR开头、且整列所有值都为0的无效列，其他列不受影响。
• 如果你需要的是剔除date2 == dmda筛选后求和为0的DR列（而非整列全0），可以去掉预处理步骤，在pivot_longer之后补充一行filter(val != 0)即可。

运行效果如下图：

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