I'd like to calculate a 5-day and 3-day cumulative sum of precipitation preceding a day containing a nitrate concentration. I have a precipitation value for each day and monthly (approximately) nitrate concentrations.
Thanks for the help!
The final output should like this: [1]: https://i.stack.imgur.com/9pYxh.png
Subset of data containing 2 days with nitrate concentrations:
| Date | PPT | NO3 |
|---|---|---|
| 7/1/1991 | 0 | NA |
| 7/2/1991 | 0 | NA |
| 7/3/1991 | 0 | NA |
| 7/4/1991 | 0 | NA |
| 7/5/1991 | 0 | NA |
| 7/6/1991 | 0 | NA |
| 7/7/1991 | 0 | NA |
| 7/8/1991 | 0 | NA |
| 7/9/1991 | 0 | NA |
| 7/10/1991 | 0 | NA |
| 7/11/1991 | 0 | NA |
| 7/12/1991 | 1.4 | NA |
| 7/13/1991 | 6 | NA |
| 7/14/1991 | 0.6 | NA |
| 7/15/1991 | 9 | 3.2 |
| 7/16/1991 | 0 | NA |
| 7/17/1991 | 2.2 | NA |
| 7/18/1991 | 0 | NA |
| 7/19/1991 | 0 | NA |
| 7/20/1991 | 3.4 | NA |
| 7/21/1991 | 3 | NA |
| 7/22/1991 | 0 | NA |
| 7/23/1991 | 0 | NA |
| 7/24/1991 | 3 | NA |
| 7/25/1991 | 0 | NA |
| 7/26/1991 | 0 | NA |
| 7/27/1991 | 0.2 | NA |
| 7/28/1991 | 0 | NA |
| 7/29/1991 | 0.4 | NA |
| 7/30/1991 | 0 | NA |
| 7/31/1991 | 0 | NA |
| 8/1/1991 | 0 | NA |
| 8/2/1991 | 0 | NA |
| 8/3/1991 | 0 | NA |
| 8/4/1991 | 0 | NA |
| 8/5/1991 | 0 | NA |
| 8/6/1991 | 0 | NA |
| 8/7/1991 | 1.4 | NA |
| 8/8/1991 | 4.6 | NA |
| 8/9/1991 | 27.4 | NA |
| 8/10/1991 | 23.8 | NA |
| 8/11/1991 | 4 | NA |
| 8/12/1991 | 5 | NA |
| 8/13/1991 | 0 | NA |
| 8/14/1991 | 0 | NA |
| 8/15/1991 | 0 | 3.09 |
CodePudding user response：
Does this approach solve your problem?
library(tidyverse)
library(lubridate)
#>
#> Attaching package: 'lubridate'
#> The following objects are masked from 'package:base':
#>
#> date, intersect, setdiff, union
df <- structure(list(Date = c("7/1/1991", "7/2/1991", "7/3/1991", "7/4/1991",
"7/5/1991", "7/6/1991", "7/7/1991", "7/8/1991", "7/9/1991", "7/10/1991",
"7/11/1991", "7/12/1991", "7/13/1991", "7/14/1991", "7/15/1991",
"7/16/1991", "7/17/1991", "7/18/1991", "7/19/1991", "7/20/1991",
"7/21/1991", "7/22/1991", "7/23/1991", "7/24/1991", "7/25/1991",
"7/26/1991", "7/27/1991", "7/28/1991", "7/29/1991", "7/30/1991",
"7/31/1991", "8/1/1991", "8/2/1991", "8/3/1991", "8/4/1991",
"8/5/1991", "8/6/1991", "8/7/1991", "8/8/1991", "8/9/1991", "8/10/1991",
"8/11/1991", "8/12/1991", "8/13/1991", "8/14/1991", "8/15/1991"
), PPT = c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1.4, 6, 0.6, 9, 0,
2.2, 0, 0, 3.4, 3, 0, 0, 3, 0, 0, 0.2, 0, 0.4, 0, 0, 0, 0, 0,
0, 0, 0, 1.4, 4.6, 27.4, 23.8, 4, 5, 0, 0, 0),
NO3 = c(NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 3.2, NA, NA,
NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 3.09)),
class = "data.frame", row.names = c(NA, -46L))
df %>%
summarise(Date = Date,
NO3 = NO3,
`5-day cumsum` = ifelse(!is.na(NO3), reduce(map(0:4, ~lag(PPT, ., 0)), ` `), NA),
`3-day cumsum` = ifelse(!is.na(NO3), reduce(map(0:2, ~lag(PPT, ., 0)), ` `), NA)) %>%
na.omit()
#> Date NO3 5-day cumsum 3-day cumsum
#> 15 7/15/1991 3.20 17 15.6
#> 46 8/15/1991 3.09 9 0.0
Created on 2022-08-30 by the reprex package (v2.0.1)