I have a block of code that look like this:
ParticipantNum <- c(1,2,4,5,7,8,9,10,13,15,16,17,18,22,24,26,27,28,29,30,32,33,35,36,39,41,43,44,45,49,50,53,54)
ParticipantTime <- c(55,54,56,88,54,79,64,52,48,21,54,87,62,35,54,87,96,96,87,53,54,52,32,89,11,28,47,78,22,14,49,75,45)
summary <- data.frame(Number=ParticipantNum,Time=ParticipantTime,Category='')
summary$Category <- ifelse(row.names(summary)<=3,"Dogs","Cats")
I am setting up a dataframe with 3 columns: Number, Time, and Category, where category is Dogs and Cats. I want my dataframe to make rows 1-3 say Dogs and all other rows say Cats. (This is an example for clarity). Somehow, when I do this, it makes rows 1-3 say Dogs, as well as rows 10-29. Rows 4-9 and 30-33 (the last row) say Cats. My intuition says it's treating row 10-29 as being "less than 3" because the first character of the row name is less than 3. I don't know why it would be doing this. I've read through the documentation for rownames and row.names but I don't understand it well enough to fix my problem. I'm new to r and relatively new to coding. Thanks.
The issue is with how row.names works. If you look at the documentation, it is subtle but says:
Row names of the form 1:n for n > 2 are stored internally in a compact form, which might be seen from C code or by deparsing but never via row.names or attr(x, "row.names").
And for numeric operations:
row.names will always return a character vector. (Use attr(x, "row.names") if you need to retrieve an integer-valued set of row names.)
So your code will work if you use attr(summary, "row.names"), but using as.numeric is probably nicer looking.
ParticipantNum <- c(1, 2, 4, 5, 7, 8, 9, 10, 13, 15, 16, 17, 18, 22, 24, 26, 27, 28, 29, 30, 32, 33, 35, 36, 39, 41, 43, 44, 45, 49, 50, 53, 54)
ParticipantTime <- c(55, 54, 56, 88, 54, 79, 64, 52, 48, 21, 54, 87, 62, 35, 54, 87, 96, 96, 87, 53, 54, 52, 32, 89, 11, 28, 47, 78, 22, 14, 49, 75, 45)
summary <- data.frame(Number = ParticipantNum, Time = ParticipantTime, Category = "")
# summary$Category <- ifelse(attr(summary, "row.names") <= 3, "Dogs", "Cats")
summary$Category <- ifelse(as.numeric(row.names(summary)) <= 3, "Dogs", "Cats")
summary
#> Number Time Category
#> 1 1 55 Dogs
#> 2 2 54 Dogs
#> 3 4 56 Dogs
#> 4 5 88 Cats
#> 5 7 54 Cats
#> 6 8 79 Cats
#> 7 9 64 Cats
#> 8 10 52 Cats
#> 9 13 48 Cats
#> 10 15 21 Cats
#> 11 16 54 Cats
#> 12 17 87 Cats
#> 13 18 62 Cats
#> 14 22 35 Cats
#> 15 24 54 Cats
#> 16 26 87 Cats
#> 17 27 96 Cats
#> 18 28 96 Cats
#> 19 29 87 Cats
#> 20 30 53 Cats
#> 21 32 54 Cats
#> 22 33 52 Cats
#> 23 35 32 Cats
#> 24 36 89 Cats
#> 25 39 11 Cats
#> 26 41 28 Cats
#> 27 43 47 Cats
#> 28 44 78 Cats
#> 29 45 22 Cats
#> 30 49 14 Cats
#> 31 50 49 Cats
#> 32 53 75 Cats
#> 33 54 45 Cats
Created on 2024-11-04 with reprex v2.1.1.9000