Repeat rows in a dataframe and fill new column with unique categories

Question

Essentially, I want to make a "Test Type" column in my data frame and fill it with the 3 tests each unique row has to undergo. I want to know how to repeat each unique row and fill the new column with the specified test.

This is an example of what my data frame looks like:

This is what my desired data frame looks like:

Please post your data using `dput()`. – tmfmnk Aug 20 '19 at 20:32 — tmfmnk, Aug 20 '19 at 20:32

akrun · Accepted Answer · 2019-08-20T20:39:03.897

Specify the replication needed in uncount for each row, expand the data, grouped by 'ID', create the 'TestType' as the concatenated 'Test' string with the sequence of rows (row_number())

library(tidyverse)
uncount(df1, 3) %>%
     group_by(ID) %>%
     mutate(TestType = str_c("Test", row_number(), sep=' '))
# A tibble: 12 x 5
# Groups:   ID [4]
#      ID Name     Age State TestType
#   <dbl> <chr>  <dbl> <chr> <chr>   
# 1   100 Bob       19 VA    Test 1  
# 2   100 Bob       19 VA    Test 2  
# 3   100 Bob       19 VA    Test 3  
# 4   102 Chase     12 NY    Test 1  
# 5   102 Chase     12 NY    Test 2  
# 6   102 Chase     12 NY    Test 3  
# 7   103 Hannah    15 CA    Test 1  
# 8   103 Hannah    15 CA    Test 2  
# 9   103 Hannah    15 CA    Test 3  
#10   104 Jason     19 CA    Test 1  
#11   104 Jason     19 CA    Test 2  
#12   104 Jason     19 CA    Test 3

Or another option is to create a list column and then unnest

df1 %>% 
    mutate(TestType = list(str_c('Test', 1:3, sep=' '))) %>% 
    unnest

data

df1 <- data.frame(ID = c(100, 102, 103, 104), Name = c("Bob", "Chase", 
  "Hannah", "Jason"), Age = c(19, 12, 15, 19),
    State = c("VA", "NY", "CA", "CA"), stringsAsFactors = FALSE)

The second option worked best for me, thank you! – dluisely Aug 21 '19 at 12:41 — dluisely, Aug 21 '19 at 12:41

score 0 · Answer 2 · answered Aug 20 '19 at 21:14

you could do:

dplyr::arrange(merge(df1,list(TestType = paste("Test",1:3))),ID)

    ID   Name Age State TestType
1  100    Bob  19    VA   Test 1
2  100    Bob  19    VA   Test 2
3  100    Bob  19    VA   Test 3
4  102  Chase  12    NY   Test 1
5  102  Chase  12    NY   Test 2
6  102  Chase  12    NY   Test 3
7  103 Hannah  15    CA   Test 1
8  103 Hannah  15    CA   Test 2
9  103 Hannah  15    CA   Test 3
10 104  Jason  19    CA   Test 1
11 104  Jason  19    CA   Test 2
12 104  Jason  19    CA   Test 3

or simply put you could do:

merge(df1,paste("Test",1:3))

which will give you the results but ordered with TestType instead of ID. You can then order using the ID column

Repeat rows in a dataframe and fill new column with unique categories

2 Answers2

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