Reshape time series data from wide to long for multiple variables

Question

I'm working with time series data in wide(ish) format for many columns that all have the format "T1_v1_slow"..."T4_v1_slow" and "T1_v1_fast"..."T4_v1_fast". There are 42 variables with this format in total. I'm trying to use pivot_longer to return each variable as a column (eg, "v1_total", "v1_Vig), with a single column for time. Example data below:

ParticipantNumber	T1_v1_total	T2_v1_total	T3_v1_total	T4_v1_total	T1_v1_Vig	T2_v1_Vig	T3_v1_Vig	T4_v1_Vig
1	41	47	45	28	8	5	8	11
2	16	25	-4	-4	11	10	18	17

I can get the data in truly long format using

data %>% 
  pivot_longer(-ParticipantNumber) %>% 
  separate(name, into = c("time", "name"), sep = 3) 

Output

ParticipantNumber	time	name	value
1	T1_	v1_total	41
1	T2_	v1_total	47
1	T3_	v1_total	45
1	T4_	v1_total	28
1	T1_	v1_Vig	8
1	T2_	v1_Vig	5
1	T3_	v1_Vig	8
1	T4_	v1_Vig	11
2	T1_	v1_total	16
2	T2_	v1_total	25
2	T3_	v1_total	-4
2	T4_	v1_total	-4
2	T1_	v1_Vig	11
2	T2_	v1_Vig	10
2	T3_	v1_Vig	18
2	T4_	v1_Vig	17

I can't use sep = "_" because I don't want to grab the second _ . My desired output is:

ParticipantNumber	time	v1_Vig	v1_total
1	T1_	8	41
1	T2_	5	47
1	T3_	8	45
1	T4_	5	28
2	T1_	11	16
2	T2_	10	25
2	T3_	18	-4
2	T4_	17	-4

Answer 1

data.frame(
  ParticipantNumber = c(1L, 2L),
        T1_v1_total = c(41L, 16L),
        T2_v1_total = c(47L, 25L),
        T3_v1_total = c(45L, -4L),
        T4_v1_total = c(28L, -4L),
          T1_v1_Vig = c(8L, 11L),
          T2_v1_Vig = c(5L, 10L),
          T3_v1_Vig = c(8L, 18L),
          T4_v1_Vig = c(11L, 17L)
) %>%
  pivot_longer(-ParticipantNumber, names_to = c("time", ".value"), names_pattern = "(.)_(.*)")

## A tibble: 8 × 4
#  ParticipantNumber time  v1_total v1_Vig
#              <int> <chr>    <int>  <int>
#1                 1 1           41      8
#2                 1 2           47      5
#3                 1 3           45      8
#4                 1 4           28     11
#5                 2 1           16     11
#6                 2 2           25     10
#7                 2 3           -4     18
#8                 2 4           -4     17

Answer 2

Simply use pivot_wider

data %>% 
  pivot_longer(-ParticipantNumber) %>% 
  separate(name, into = c("time", "name"), sep = 3) %>%
  pivot_wider(values_fn=sum)