Add a new column by mutate involving a conditional

Question

I need to add a new column in dplyr by mutate involving an conditional. I can't find a way to implement the following scheme in the tidyverse, but I can do it Excel. That makes me feel like something of a barbarian. Does someone know how to accomplish this in the tidyverse?

The first value of the running count column is 1, no matter what is in the "n" column.
After the first row, here is the conditional. If the n column=1, the running.count output is the running.count value from the row above +1. If the n column=0, the running.count output is the running.count value from the row above +1 only when it is the first 0 after a 1 in the "n" column. Otherwise, it is just the running.count value from the row above.

Here's some toy data with the desired output:

data.frame("n"=c(0,1,0,0,0,0,1,0,1,1),"running.count"=c(1,2,3,3,3,3,4,5,6,7))

Can you try library(dplyr); library(data.table);df1 %>% group_by(running.count = rleid(n) ) %>% mutate(ind = if(all(n==1)) duplicated(n) else FALSE) %>% ungroup %>% mutate(running.count = running.count + ind) %>% select(-ind) — akrun
Try df2 %>% group_by(running.count = rleid(n) ) %>% mutate(ind = if(all(n==1)) row_number() - 1 else 0) %>% ungroup %>% mutate(running.count = rleid(running.count, ind)) %>% select(-ind) — akrun
@akrun That looks correct to me. I would mark it as answered, but I don't see how to do that for you. Thank you so much!! — curiositasisasinbutstillcuriou

akrun akrun · Accepted Answer · 2019-05-03T18:24:11

We can use rleid from data.table to create the running.count column

library(dplyr)
library(data.table)
df1 %>% 
   group_by(running.count = rleid(n) ) %>% 
   mutate(ind = if(all(n==1))  row_number() - 1 else 0) %>% 
   ungroup %>% 
   mutate(running.count = rleid(running.count, ind)) %>% 
   select(-ind)
# A tibble: 10 x 2
#       n running.count
#   <dbl>         <int>
# 1     0             1
# 2     1             2
# 3     0             3
# 4     0             3
# 5     0             3
# 6     0             3
# 7     1             4
# 8     0             5
# 9     1             6
#10     1             7

data

df1 ,- structure(list(n = c(0, 1, 0, 0, 0, 0, 1, 0, 1, 1)), 
   class = "data.frame", row.names = c(NA, -10L))

Add a new column by mutate involving a conditional

1 Answers

data