Count the length of each event by group-CodePudding

I am counting the events with multiple conditions and my final result is represented for each year seperately. The example of my df:

year <- c(rep(1981,20))
k1 <- c(rep(NA,5),rep("COLD",4),rep(NA,4),"COLD",NA,"COLD",rep(NA,4))
k2 <- c(rep(NA,10),rep("COLD",2),rep(NA,8))
k3 <- c(rep(NA,3),"COLD",rep(NA,16))
k4 <- c(rep(NA,3),rep("COLD",5),rep(NA,2),rep("COLD",6),NA,rep("COLD",3))
k5 <- c(rep(NA,3),"COLD",rep(NA,3),"COLD",rep(NA,3),"COLD",rep(NA,8))

df <- data.frame(year,k1,k2,k3,k4,k5)

The code I use is below:

rle_col <-  function(k_col) {
         with(rle(is.na(k_col)), {
         i1 <- values
         i1[values & lengths <= 2] <- 'Invalid'
         sum(!values & lengths >= 5 & 
                 (lead(i1) != "Invalid" & lag(i1)>=1), na.rm = TRUE)
         
     })
 }

rezult <- df %>% 
    group_by(year) %>% 
    summarise(across(starts_with('k'), rle_col))

My code works well, but I need to get one more variable - the length of each event (or the number of members in each event). This means that instead of sum here sum(!values & lengths >= 5 & (lead(i1) != "Invalid" & lag(i1)>=1), na.rm = TRUE) I need to get the number of values within each event, which satisfies these conditions. Is it possible? Thank you for any help. The result I would like to see should be as follows:

Year  k4
1981  5
1981  10

CodePudding user response：

There have to be easy solutions for this problem. Here is a ridiculous complicated (and not well performing) approach using tidyverse:

library(tidyr)
library(dplyr)
library(purrr)

map_df(
  names(df)[grepl("^k", names(df))],
  ~df %>% 
    group_by(year) %>% 
    mutate(
      grp = (!!sym(.x) == "COLD" & !is.na(!!sym(.x))) | 
        !(is.na(lead(!!sym(.x))) | is.na(lag(!!sym(.x))))
      ) %>% 
    group_by(year, grp2 = cumsum(!grp)) %>% 
    filter(grp) %>% 
    count(name = .x) %>% 
    filter(!!sym(.x) >= 5) %>% 
    ungroup() %>% 
    select(-grp2)
)

This returns

# A tibble: 2 x 6
   year    k1    k2    k3    k4    k5
  <dbl> <int> <int> <int> <int> <int>
1  1981    NA    NA    NA     5    NA
2  1981    NA    NA    NA    10    NA

Issues:

It's not performing well.
If there are several groups in different columns the output looks like this:

# A tibble: 9 x 6
   year    k1    k2    k3    k4    k5
  <dbl> <int> <int> <int> <int> <int>
1  1981     4    NA    NA    NA    NA
2  1981     3    NA    NA    NA    NA
3  1981    NA     2    NA    NA    NA
4  1981    NA    NA     1    NA    NA
5  1981    NA    NA    NA     5    NA
6  1981    NA    NA    NA    10    NA
7  1981    NA    NA    NA    NA     1
8  1981    NA    NA    NA    NA     1
9  1981    NA    NA    NA    NA     1

At the moment I don't know how to change it into something like

# A tibble: 2 x 6
    year    k1    k2    k3    k4    k5
   <dbl> <int> <int> <int> <int> <int>
 1  1981     4     2     1     5     1
 2  1981     3    NA    NA    10     1