My question is regards accessing complex lists. I am new to R, but experienced in Java, Python, SQL.
I am working with an object: Dataprocess and in it slot: data that is a list. Also I am creating generic functions to perform on the slot: data which is the list. I am working with the Airline dataset - so the data slot is a list of the years 1987, 1988, .. I am trying to perform factor and such operations on the column elements of each year. So - for purposes of this discussion we will refer to the column: dayOfWeek in each of the years. My issue is that while I get to the list I need I cannot directly access the list elements to apply the factor function to. I can print the list directly. I try to explain as follows: ... So the data has several columns. And in the method I can get to a column using: x <- list(lapply(this@data, '[[', ‘dayOfWeek’)) print(x) OR print(x[1]) >> gives: [[1]] [[1]]$`1987` [1] 3 4 6 7 1 3 4 5 6 7 1 3 4 6 4 5 ... print(x[[1]]) >> gives: $`1987` [1] 3 4 6 7 1 3 4 5 6 7 1 3 4 6 4 5 ... If I do: z <- factor(x) OR z <- factor(x[1]) OR z <- factor(x[[1]]) I get Error in sort.list(y) : 'x' must be atomic for 'sort.list' Have you called 'sort' on a list? ... I have also tried: y <- list(sapply(this@data, '[', ‘dayOfWeek’)) print(y) OR print (y[1]) >> gives: [[1]] [[1]]$`1987.dayOfWeek` [1] 3 4 6 7 1 3 4 5 6 7 1 3 4 6 4 5 ... print(y[[1]]) >> gives: $`1987.dayOfWeek` [1] 3 4 6 7 1 3 4 5 6 7 1 3 4 6 4 5 ... Again If I do: z <- factor(y) OR z <- factor(y[1]) OR z <- factor(y[[1]]) I get Error in sort.list(y) : 'x' must be atomic for 'sort.list' Have you called 'sort' on a list? I have tried accessing the list directly as y[[1]]$’1987.dayOfWeek’ which gives me the list elements. And then factor(y[[1]]$’dayOfWeek’) works fine! Gives me: [1] 3 4 6 7 1 3 4 5 6 7 1 3 4 6 4 5 ... Levels: 1 2 3 4 5 6 7 But I do not have this flexibility as I am doing the lapply or sapply as part of a for loop. So the functions are really: x <- list(lapply(this@data, '[[', each)) y <- list(sapply(this@data, '[', each)) So it is not possible for me to access in a hard-coded manner as y[[1]]$’1987.dayOfWeek’ So I do not understand how to access the list elements directly to apply factor and not just the list. None of the accesses as x, x[1], x[[1]] OR y, y[1] or y[[1]] work. It gives me access to the list for print and such - but not to the list elements to apply factor. The only way to access the list elements directly is by y[[1]]$’1987.dayOfWeek’ and then I can factor. However I do not have this option as I am in a loop. I hope I have explained this clearly. If not please let me know and I can try again or post the code. Thank you for your help. Mono -- View this message in context: http://r.789695.n4.nabble.com/Accessing-List-within-a-List-in-a-for-Loop-tp4651086.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
