ifelse in ddply summarize not working when doing max

Question

I'm trying to use ddply to summarize a dataframe in R and its working fine unless I add ifelse to find the maximum datetime (last time) when a field is NOT matching the value, its giving Null in most cases. DOn't know where I'm going wrong.

"last_act_date" = max(ifelse(name == "$view", time, NA)),

Full code is

ahoy_unique_users <- ddply(ahoy_events_acc, .(account_id), summarise, 
                           "start_date" = as.Date(min(time)),
                           "last_date" = as.Date(max(time)),
                           "last_act_date" = max(ifelse(name == "$view", time, NA))
                           )

Answer 1

plyr has been long retired and I would suggest to use dplyr instead. A reproducible example would have been helpful to understand the problem. With dplyr you can try :

library(dplyr)

ahoy_events_acc %>%
  mutate(time = as.Date(time)) %>%
  group_by(account_id) %>%
  summarise(start_date = min(time), 
            last_date = max(time), 
            last_act_date = max(time[name == "$view"]))

I think last_act_date = max(time[name == "$view"])) should work in your plyr code too.