R语言：如何筛选/标记包含全部工作日数据的周？

你的for循环逻辑存在两个核心问题：

1. 每次循环都在检查整个数据集的day是否全部属于工作日列表，而非针对当前周（i对应的分组）的日期进行判断；
2. 循环中每次都会覆盖整个flag列，最终结果是全局判断的结论（你的数据集中存在非工作日，所以all(reprex$day %in% weekdays)始终为FALSE，导致所有标记为0）。

另外，cbind会将数据转换为字符矩阵，再转为data.frame时会把week_num变成字符型，建议直接用data.frame(week_num, day)创建数据集，避免类型问题。

方法1：使用dplyr（推荐，适合大型数据集） #

利用分组操作高效判断每个周是否包含全部工作日：

library(dplyr)

# 构造数据集（避免cbind导致的类型问题）
week_num <- c(1,1,1,1,1,2,2,2,3,3,3,3)
day <- c("Monday", "Tuesday", "Thursday", "Wednesday", "Friday", "Friday", "Sunday", "Saturday", "Thursday", "Wednesday", "Tuesday", "Sunday")
reprex <- data.frame(week_num, day)

weekdays <- c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday")

# 分组判断并生成标记列
reprex <- reprex %>%
  group_by(week_num) %>%
  mutate(flag = ifelse(all(weekdays %in% day), 1, 0)) %>%
  ungroup()

print(reprex)

关键逻辑：all(weekdays %in% day)用于检查当前分组的日期是否包含所有工作日，而非检查所有日期是否都是工作日。

方法2：使用base R（无需额外包） #

用ave函数实现分组判断：

week_num <- c(1,1,1,1,1,2,2,2,3,3,3,3)
day <- c("Monday", "Tuesday", "Thursday", "Wednesday", "Friday", "Friday", "Sunday", "Saturday", "Thursday", "Wednesday", "Tuesday", "Sunday")
reprex <- data.frame(week_num, day)

weekdays <- c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday")

# 生成标记列
reprex$flag <- with(reprex, ave(day, week_num, FUN = function(x) {
  as.integer(all(weekdays %in% x))
}))

print(reprex)

方法3：修正你的for循环（不推荐，大型数据集效率低） #

如果坚持用循环，需要针对每个周的子集进行判断，并仅更新对应分组的标记：

week_num <- c(1,1,1,1,1,2,2,2,3,3,3,3)
day <- c("Monday", "Tuesday", "Thursday", "Wednesday", "Friday", "Friday", "Sunday", "Saturday", "Thursday", "Wednesday", "Tuesday", "Sunday")
reprex <- data.frame(week_num, day)

weekdays <- c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday")

# 初始化标记列为0
reprex$flag <- 0

for (i in unique(reprex$week_num)) {
  # 获取当前周的所有日期
  current_days <- reprex$day[reprex$week_num == i]
  # 判断是否包含全部工作日
  if (all(weekdays %in% current_days)) {
    # 更新当前周的标记为1
    reprex$flag[reprex$week_num == i] <- 1
  }
}

print(reprex)

内容的提问来源于stack exchange，提问作者Abbey A.