dplyr, lubridate : how to aggregate a dataframe by week?

Question

Consider the following example

library(tidyverse)
library(lubridate)
time <- seq(from =ymd(\"2014-02-24\"),to= ymd(\"2014-03-20\"), by=\"days\")
set.seed(         


        

Answer 1

Just this once, after some research, I actually think I came up with a better solution that

• gives the correct aggregation
• gives the correct labels

Example below for weeks starting on a thursday. The weeks will be labeled by their first day a given cycle.

library(tidyverse)
library(lubridate)
options(tibble.print_min = 30)

time <- seq(from =ymd("2014-02-24"),to= ymd("2014-03-20"), by="days")
set.seed(123)
values <- sample(seq(from = 20, to = 50, by = 5), size = length(time), replace = TRUE)
df2 <- data_frame(time, values)

df2 <- df2 %>% mutate(day_of_week_label = wday(time, label = TRUE),
                      day_of_week = wday(time, label = FALSE))

df2 <- df2 %>% mutate(thursday_cycle = time - ((as.integer(day_of_week) - 5) %% 7),
                      tmp_1 = (as.integer(day_of_week) - 5),
                      tmp_2 = ((as.integer(day_of_week) - 5) %% 7))

which gives

> df2
# A tibble: 25 × 7
         time values day_of_week_label day_of_week thursday_cycle tmp_1 tmp_2
                                        
1  2014-02-24     30               Mon           2     2014-02-20    -3     4
2  2014-02-25     45              Tues           3     2014-02-20    -2     5
3  2014-02-26     30               Wed           4     2014-02-20    -1     6
4  2014-02-27     50             Thurs           5     2014-02-27     0     0
5  2014-02-28     50               Fri           6     2014-02-27     1     1
6  2014-03-01     20               Sat           7     2014-02-27     2     2
7  2014-03-02     35               Sun           1     2014-02-27    -4     3
8  2014-03-03     50               Mon           2     2014-02-27    -3     4
9  2014-03-04     35              Tues           3     2014-02-27    -2     5
10 2014-03-05     35               Wed           4     2014-02-27    -1     6
11 2014-03-06     50             Thurs           5     2014-03-06     0     0
12 2014-03-07     35               Fri           6     2014-03-06     1     1
13 2014-03-08     40               Sat           7     2014-03-06     2     2
14 2014-03-09     40               Sun           1     2014-03-06    -4     3
15 2014-03-10     20               Mon           2     2014-03-06    -3     4
16 2014-03-11     50              Tues           3     2014-03-06    -2     5
17 2014-03-12     25               Wed           4     2014-03-06    -1     6
18 2014-03-13     20             Thurs           5     2014-03-13     0     0
19 2014-03-14     30               Fri           6     2014-03-13     1     1
20 2014-03-15     50               Sat           7     2014-03-13     2     2
21 2014-03-16     50               Sun           1     2014-03-13    -4     3
22 2014-03-17     40               Mon           2     2014-03-13    -3     4
23 2014-03-18     40              Tues           3     2014-03-13    -2     5
24 2014-03-19     50               Wed           4     2014-03-13    -1     6
25 2014-03-20     40             Thurs           5     2014-03-20     0     0