I have a data.frame with some prices per day. I would like to get the average daily price in another column (avg_price). How can I do that ?
date price avg_price
1 2017-01-01 01:00:00 10 18.75
2 2017-01-01 01:00:00 10 18.75
3 2017-01-01 05:00:00 25 18.75
4 2017-01-01 04:00:00 30 18.75
5 2017-01-02 08:00:00 10 20
6 2017-01-02 08:00:00 30 20
7 2017-01-02 07:00:00 20 20
>Solution :
library(lubridate)
library(tidyverse)
df %>%
group_by(day = day(date)) %>%
summarise(avg_price = mean(price))
# A tibble: 2 x 2
day avg_price
<int> <dbl>
1 1 18.8
2 2 20
df %>%
group_by(day = day(date)) %>%
mutate(avg_price = mean(price))
# A tibble: 7 x 4
# Groups: day [2]
date price avg_price day
<dttm> <dbl> <dbl> <int>
1 2017-01-01 01:00:00 10 18.8 1
2 2017-01-01 01:00:00 10 18.8 1
3 2017-01-01 05:00:00 25 18.8 1
4 2017-01-01 04:00:00 30 18.8 1
5 2017-01-02 08:00:00 10 20 2
6 2017-01-02 08:00:00 30 20 2
7 2017-01-02 07:00:00 20 20 2