在 R 中按用户名和时间合并以获取长格式数据

Question

I have a long format data frame. A username may have 1 to multiple observations in time (1,2,3),

username score time 

a         10     1

a         20     2

a         10     2

a         30     3

b         10     2

b         20     3

I hope to merge the dataset by username and time and get a mean (score)

For each time (1,2,3), a username will have only one score for one time.

This means that for each username, he/she will have 3 observations in time (1,2,3)

Something like this:

username score time 

a         10     1

a         15     2

a         30     3

b         10     2

b         20     3

b         na     1

Answer 1

If we need a summarised output

library(dplyr)
library(hablar)
library(tidyr)
df2 <- df1 %>%
          group_by(username, time) %>%
          summarise(score = mean_(score), .groups = 'drop') %>%
          complete(username, time)

-output

# A tibble: 6 x 3
#  username  time score
#  <chr>    <int> <dbl>
#1 a            1    10
#2 a            2    15
#3 a            3    30
#4 b            1    NA
#5 b            2    10
#6 b            3    20

data

df1 <- structure(list(username = c("a", "a", "a", "a", "b", "b"), score = c(10L, 
20L, 10L, 30L, 10L, 20L), time = c(1L, 2L, 2L, 3L, 2L, 3L)), 
      class = "data.frame", row.names = c(NA, 
-6L))