通过替换 R 中的单元格复制行

Question

I am very new to R, and let me explain the problem. I have the following data.frame:

df1<-data.frame(name = c("Ann", "Beth", "Jon", "Mark"),
test1 = c(1,3,2,3),
test2 = c("B",NA,"C",NA)
)

Simply speaking, there are four people. Two of them took only test1 and have results for that test. The other two took both tests. I wish to transform this data.frame into the following:

df2<-data.frame(name = c("Ann", "Ann", "Beth", "Jon", "Jon", "Mark"),
test1 = c(1,"B",3,2,"C",3)
)

In other words, I wish to have all test results in one column. The order does not matter in sense that, for example, "second Ann" can be in the last row than in the second row. Since Ann and Jon took two tests, I (i) created an additional row for both of them, (ii) copied their test2 results into test1, and (iii) deleted test2 column.

My attempt. I first duplicated rows which have nonempty values in test2:

df1 <- bind_rows(df1, 
              df1 %>%
                filter_at(vars(starts_with("test2")), all_vars(!is.na(.))))

Now I cannot wrap my head around how to transfer test2 results in new rows into test1.

Answer 1

Does this work:

df1 %>% mutate(test1 = as.character(test1)) %>% pivot_longer(!name, names_to = 'test') %>% select(-2) %>% na.omit()
# A tibble: 6 x 2
  name  value
  <chr> <chr>
1 Ann   1    
2 Ann   B    
3 Beth  3    
4 Jon   2    
5 Jon   C    
6 Mark  3