Question

I have some events I am trying to enumerate in my data based on the order in which the occur, but conditioned on another variable (in this case Date) is not missing. I’ve somewhat stuck. My problem is that I need to do it only using base-R.

Here is an working example:

df <-
structure(list(Date = c("Sep 02 2012", "Sep 10 2012", "Sep 22 2012", 
"Sep 23 2012", "Sep 23 2012", "Sep 23 2012", "Sep 24 2012", "Sep 24 2012", 
"Sep 24 2012", "Dec 01 2012", "Sep 09 2014", NA), Event = c("005", 
"006", "002", "003", "004", "007", "008", "010", "011", "012", 
"009", "001"), Type = c("IND", "IND", "CON", "OUT", "OUT", "IND", 
"CMA", "ASH", "CON", "ASH", "CMA", "IND")), .Names = c("Date", 
"Event", "Type"), class = "data.frame", row.names = c(13L, 14L, 
10L, 11L, 12L, 15L, 16L, 18L, 19L, 20L, 17L, 9L))

Gives me this data frame,

df
          Date Event Type
13 Sep 02 2012   005  IND
14 Sep 10 2012   006  IND
10 Sep 22 2012   002  CON
11 Sep 23 2012   003  OUT
12 Sep 23 2012   004  OUT
15 Sep 23 2012   007  IND
16 Sep 24 2012   008  CMA
18 Sep 24 2012   010  ASH
19 Sep 24 2012   011  CON
20 Dec 01 2012   012  ASH
17 Sep 09 2014   009  CMA
9         <NA>   001  IND

What I would like to get,

new.df

       Date    Event Type Num_Type
13 Sep 02 2012   005  IND       1
14 Sep 10 2012   006  IND       2
10 Sep 22 2012   002  CON       1
11 Sep 23 2012   003  OUT       1
12 Sep 23 2012   004  OUT       2
15 Sep 23 2012   007  IND       3
16 Sep 24 2012   008  CMA       1
18 Sep 24 2012   010  ASH       1
19 Sep 24 2012   011  CON       1
20 Dec 01 2012   012  ASH       2
17 Sep 09 2014   009  CMA       2
9         <NA>   001  IND      NA

Answer 1

You can do this with ave and cumsum:

df$Num_Type <- 1
df$Num_Type <- ave(df$Num_Type, df$Type, FUN=cumsum)
is.na(df$Num_Type) <- which(is.na(df$Date))