R: How to subset dataframe by group?

Question

I have the following data frame called groceries :

Region    Item    Barcode    Version
East     Cereal    BM        2.1
North    Bagel     EP        2.0
East     Pizza     BM        2.3
West     Taco      EP        2.2
West     Apple     BM        3.0
South    Orange    EP        3.2
North    Tomato    EP        2.2
South    Grape     EP        2.0
East     Pineapple EP        3.2
North    Cake      BM        2.0

How do I subset the data frame by Barcode-Version to get the following data frames?

data frame

Region    Item    Barcode    Version
East     Cereal    BM        2.1
East     Pizza     BM        2.3
North    Cake      BM        2.0

data frame

Region    Item    Barcode    Version
West     Apple     BM        3.0

data frame

Region    Item    Barcode    Version
North    Bagel     EP        2.0
North    Tomato    EP        2.2
South    Grape     EP        2.0
West     Taco      EP        2.2

data frame

Region    Item    Barcode    Version
South    Orange    EP        3.2
East     Pineapple EP        3.2

As you can see, I'm trying to subset the original data frame by barcode and version (as an integer; so 2.0, 2.1, 2.3 are all considered 2, etc.).

Here's what I have so far:

subset(groceries, Barcode=="BM" & Version==2.0 | Version==2.1 | Version==2.3)

As you can imagine this is not ideal. Is there a way that I can get vectors of the different factors for Barcode and Version (as integers)? If I can get those two as a vectors then I can probably create a for loop that automates the line above to create these 4 data frames.

Answer 1

split(df, interaction(df$Barcode, floor(df$Version)))
# $BM.2
# Region   Item Barcode Version
# 1    East Cereal      BM     2.1
# 3    East  Pizza      BM     2.3
# 10  North   Cake      BM     2.0
# 
# $EP.2
# Region   Item Barcode Version
# 2  North  Bagel      EP     2.0
# 4   West   Taco      EP     2.2
# 7  North Tomato      EP     2.2
# 8  South  Grape      EP     2.0
# 
# $BM.3
# Region  Item Barcode Version
# 5   West Apple      BM       3
# 
# $EP.3
# Region      Item Barcode Version
# 6  South    Orange      EP     3.2
# 9   East Pineapple      EP     3.2