R 中的日期：计算实例和天数

Question

我正在处理水质数据，其中包含采样地点、采样日期以及每个采样的结果。每当样本结果大于 104 时，就会触发建议。单个咨询计数一次，但会持续多少天，直到新样本数据反映等于或低于 104 的结果为止。咨询计数的长度从触发咨询的第一天开始，一直计数到，但不计算包括结果等于或低于 104 的日期。我正在寻找一种方法来计算每个位置的建议总数以及建议的平均长度（以天为单位）。谢谢！！

Answer 1

library(dplyr)

df %>%
  summarize(advisory_period = sum(RESULT > 104), .by = SITE_ID) %>%
  bind_rows(
    df %>%
      summarize(advisory_period = sum(RESULT > 104), .by = SITE_ID) %>%
      summarize(SITE_ID = 'average_period',
                advisory_period = mean(advisory_period)
  ))
#> # A tibble: 4 × 2
#>   SITE_ID        advisory_period
#>   <chr>                    <dbl>
#> 1 ARA001                       4
#> 2 BRA001                       3
#> 3 CRA001                       5
#> 4 average_period               4

数据

df <- structure(list(SITE_ID = c("ARA001", "ARA001", "ARA001", "ARA001", 
                                   "ARA001", "ARA001", "ARA001", "BRA001", "BRA001", "BRA001", "BRA001", 
                                   "BRA001", "BRA001", "BRA001", "CRA001", "CRA001", "CRA001", "CRA001", 
                                   "CRA001", "CRA001", "CRA001", "CRA001", "CRA001"), RESULT = c(13, 
                                                                                                 107, 10, 115, 120, 110, 80, 5, 5, 112, 105, 5, 118, 5, 154, 180, 
                                                                                                 2000, 1543, 103, 100, 80, 112, 5), DATE = c("1/3/2023", "1/17/2023", 
                                                                                                                                             "1/30/2023", "2/13/2023", "2/27/2023", "3/6/2023", "3/7/2023", 
                                                                                                                                             "1/3/2023", "1/18/2023", "1/25/2023", "2/7/2023", "2/17/2023", 
                                                                                                                                             "3/28/2023", "3/7/2023", "1/2/2023", "1/5/2023", "1/6/2023", 
                                                                                                                                             "1/7/2023", "1/9/2023", "2/6/2023", "2/17/2023", "2/21/2023", 
                                                                                                                                             "3/6/2023")), row.names = c(NA, -23L), spec = structure(list(
                                                                                                                                               cols = list(`SITE ID` = structure(list(), class = c("collector_character", 
                                                                                                                                                                                                   "collector")), RESULT = structure(list(), class = c("collector_double", 
                                                                                                                                                                                                                                                       "collector")), DATE = structure(list(), class = c("collector_character", 
                                                                                                                                                                                                                                                                                                         "collector"))), default = structure(list(), class = c("collector_guess", 
                                                                                                                                                                                                                                                                                                                                                               "collector")), delim = ","), class = "col_spec"), class = c("spec_tbl_df", 
                                                                                                                                                                                                                                                                                                                                                                                                                           "tbl_df", "tbl", "data.frame"))

^{创建于 2024-03-21，使用 reprex v2.0.2}