R how Sum values by group by date

Question

I have this table already in variable DATA in R, loaded from csv

country, date, confirmed    
Afghanistan, 2020-03-16, 21
Afghanistan, 2020-03-17, 22
Afghanistan, 2020-03-18, 22
Albania, 2020-03-16, 23
Albania, 2020-03-17, 33
Albania, 2020-03-18, 38
...

I would like to make this query in R

select date, sum(confirmed) as confirmed FROM `Table` group by date

Any idea pls ?

So results should be this

date,confirmed
2020-03-16, 44
2020-03-17, 55
2020-03-18, 60

score 4 · Accepted Answer · answered May 01 '20 at 18:47

4

With aggregate from base R

aggregate(confirmed ~ date, Table, sum, na.rm = TRUE)

Or with dplyr

library(dplyr)
Table %>%
  group_by(date) %>%
  summarise(confirmed = sum(confirmed, na.rm = TRUE))

answered May 01 '20 at 18:47

akrun

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linog · Answer 2 · 2020-05-01T19:20:22.213

2

A data.table implementation :

library(data.table)
setDT(Table)
Table[,.(confirmed = sum(confirmed)), by = date]

edited May 01 '20 at 19:20

answered May 01 '20 at 19:16

linog

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1

Yes you're right, I edited :) – linog May 01 '20 at 19:21

R how Sum values by group by date

2 Answers2