基于DATE的R中多列的差异[重复]

Question

我有这个数据：

structure(list(new_col = c(1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 
6, 7, 1, 2, 3, 4, 5, 6, 7), DATE = structure(c(1608249600, 1608249600, 
1608249600, 1608249600, 1608249600, 1608249600, 1608249600, 1608336000, 
1608336000, 1608336000, 1608336000, 1608336000, 1608336000, 1608336000, 
1608422400, 1608422400, 1608422400, 1608422400, 1608422400, 1608422400, 
1608422400), tzone = "UTC", class = c("POSIXct", "POSIXt")), 
    HOSP_COUNT = c(582, 931, 1472, 2175, 2791, 3024, 2310, 588, 
    932, 1477, 2186, 2810, 3051, 2330, 590, 932, 1479, 2188, 
    2817, 3060, 2335)), row.names = c(NA, -21L), class = c("tbl_df", 
"tbl", "data.frame"))

HOPS_COUNT 是一个累积变量，而我需要每天测量。像这样：

structure(list(X1 = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 
13, 14, 15, 16, 17, 18, 19, 20, 21), new_col = c(1, 2, 3, 4, 
5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7), DATE = c("12/18/2020", 
"12/18/2020", "12/18/2020", "12/18/2020", "12/18/2020", "12/18/2020", 
"12/18/2020", "12/19/2020", "12/19/2020", "12/19/2020", "12/19/2020", 
"12/19/2020", "12/19/2020", "12/19/2020", "12/20/2020", "12/20/2020", 
"12/20/2020", "12/20/2020", "12/20/2020", "12/20/2020", "12/20/2020"
), HOSP_COUNT = c(582, 931, 1472, 2175, 2791, 3024, 2310, 6, 
1, 5, 11, 19, 27, 20, 2, 1, 2, 2, 7, 9, 15)), row.names = c(NA, 
-21L), class = c("tbl_df", "tbl", "data.frame"))

所以我需要一个新列，公式是 (new_col(1) 在第二天 (12/19/2020) 的 HOPS_CASE = (new_col(1) 在第一天 12/18/2020)-(new_col(1) 在第一天的 CASE_HOSP 12 /19/2020)

Answer 1

这应该适合你：

library(dplyr)

df %>% 
  group_by(new_col) %>% 
  mutate(new_count = HOSP_COUNT - lag(HOSP_COUNT),
         new_count = ifelse(is.na(new_count), HOSP_COUNT, new_count))

new_count 是您的更正计数：

# A tibble: 20 x 4
# Groups:   new_col [7]
   new_col DATE                HOSP_COUNT new_count
     <dbl> <dttm>                   <dbl>     <dbl>
 1       1 2020-12-18 00:00:00        582       582
 2       2 2020-12-18 00:00:00        931       931
 3       3 2020-12-18 00:00:00       1472      1472
 4       4 2020-12-18 00:00:00       2175      2175
 5       5 2020-12-18 00:00:00       2791      2791
 6       6 2020-12-18 00:00:00       3024      3024
 7       7 2020-12-18 00:00:00       2310      2310
 8       1 2020-12-19 00:00:00        588         6
 9       2 2020-12-19 00:00:00        932         1
10       3 2020-12-19 00:00:00       1477         5
11       4 2020-12-19 00:00:00       2186        11
12       5 2020-12-19 00:00:00       2810        19
13       6 2020-12-19 00:00:00       3051        27
14       7 2020-12-19 00:00:00       2330        20
15       1 2020-12-20 00:00:00        590         2
16       2 2020-12-20 00:00:00        932         0
17       3 2020-12-20 00:00:00       1479         2
18       4 2020-12-20 00:00:00       2188         2
19       5 2020-12-20 00:00:00       2817         7
20       6 2020-12-20 00:00:00       3060         9