Summarising by a group variable in r

Question

I have a data frame as follows:

 head(newStormObject)
     FATALITIES   INJURIES    PROPVALDMG CROPVALDMG      EVTYPE     total
 1           0          15    2.5         


        

Answer 1

We can take the first value for all the other columns using slice after updating the 'total' with the sum of 'total'.

library(dplyr)
df1 %>% 
   group_by(EVTYPE) %>% 
   mutate(total = sum(total)) %>%
   slice(1L) %>%
   arrange(desc(total))
#      FATALITIES INJURIES PROPVALDMG CROPVALDMG    EVTYPE total
#                             
#1          0       15     250000          0   TORNADO    21
#2          0        0          0          0      HAIL    12
#3          0        0          0          0 TSTM WIND     1

NOTE: The 'total' for 'EVTYPE' "HAIL" is 12 based on the example