Open ManytoMany left.csv:

Open ManytoMany right.csv:

left <- read.csv('ManytoMany left.csv')

right <- read.csv('ManytoMany right.csv')

left

   key  Veggies

1  Mon Broccoli

2  Mon   Celery

3  Mon  Lettuce

4  Wed Broccoli

5  Wed   Celery

6  Thu Broccoli

7  Thu   Celery

8  Thu  Lettuce

9  Fri Broccoli

10 Fri   Celery

 

right

  key   Fruits

1 Mon   Apples

2 Mon  Bananas

3 Mon Cherries

4 Tue   Apples

5 Tue  Bananas

6 Wed   Apples

7 Wed  Bananas

8 Wed Cherries

9 Fri   Apples

inner <- merge(x = left, y = right, by = 'key')

inner

   key  Veggies   Fruits

1  Fri Broccoli   Apples

2  Fri   Celery   Apples

3  Mon Broccoli  Bananas

4  Mon Broccoli Cherries

5  Mon Broccoli   Apples

6  Mon   Celery  Bananas

7  Mon   Celery Cherries

8  Mon   Celery   Apples

9  Mon  Lettuce  Bananas

10 Mon  Lettuce Cherries

11 Mon  Lettuce   Apples

12 Wed   Celery   Apples

13 Wed   Celery  Bananas

14 Wed   Celery Cherries

15 Wed Broccoli   Apples

16 Wed Broccoli  Bananas

17 Wed Broccoli Cherries

# Or with the dplyr package

library(dplyr)

i_join <- left %>% inner_join(right, by = 'key')

# Or by default

i_join <- left %>% inner_join(right)

i_join

   key  Veggies   Fruits

1  Mon Broccoli   Apples

2  Mon Broccoli  Bananas

3  Mon Broccoli Cherries

4  Mon   Celery   Apples

5  Mon   Celery  Bananas

6  Mon   Celery Cherries

7  Mon  Lettuce   Apples

8  Mon  Lettuce  Bananas

9  Mon  Lettuce Cherries

10 Wed Broccoli   Apples

11 Wed Broccoli  Bananas

12 Wed Broccoli Cherries

13 Wed   Celery   Apples

14 Wed   Celery  Bananas

15 Wed   Celery Cherries

16 Fri Broccoli   Apples

17 Fri   Celery   Apples

Functions referenced:

read.csv

merge

inner_join (page 28)

More information:

RStudio Data Wrangling Cheatsheet

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