I have two list objects. l1
contains information that has been read in through path files. l2
is a list of values that have similar name components as those in l1
. I have assigned attributes to both list based on the names of the elements in the list. I would like to reach my expected results using the attributes that I have assigned to my list.
For example: I would like to apply a function mean()
between the elements with the attribute id
that are "2013_mean" in l1
to those with the attribute year
that are also "2013" in l2
. I would like to do the similar thing with those when the attribute for year is "2016".
# File List
l1 <- list(2,3,4,5)
names(l1) <- c("C:/Users/2013_mean.csv",
"C:/Users/2013_median.csv",
"C:/Users/2016_mean.csv",
"C:/Users/2016_median.csv")
attributes(l1) <- data.frame(id = sub("\\.csv", "", basename(names(l1))),
year = trimws(basename(names(l1)), whitespace = "_.*"))
# Other List
l2 <- list(8,9,10,15,1)
names(l2) <- c("2013_A",
"2013_B",
"2013_C",
"2016_D",
"2016_E")
attributes(l2) <- data.frame(year = trimws(names(l2), whitespace = "_.*"))
expected <- list(mean(c(l1[[1]], l2[[1]])),
mean(c(l1[[1]], l2[[2]])),
mean(c(l1[[1]], l2[[3]])),
mean(c(l1[[3]], l2[[4]])),
mean(c(l1[[3]], l2[[5]]))
)
CodePudding user response:
We may use the attributes to split and match and get the mean
i1 <- grepl("mean", attr(l1, "id"))
l1new <- l1[i1]
attr(l1new, "year") <- attr(l1, "year")[i1]
out <- do.call(c, Map(function(x, y) lapply(x, function(z)
mean(c(z, y))), split(l2, attr(l2, 'year')), l1new))
names(out) <- NULL
-checking with OP's expected
> identical(out, expected)
[1] TRUE
Or another option is to convert the list
with attributes to a data.frame, do a merge
and use rowMeans
and then convert to list
with as.list
as.list(rowMeans(merge(transform(data.frame(attributes(l2)),
l2 = unlist(l2)),
subset(transform(data.frame(attributes(l1)), l1 = unlist(l1)),
grepl("mean", id), select = c(year, l1)), all.x = TRUE)[-1]))
-output
[[1]]
[1] 5
[[2]]
[1] 5.5
[[3]]
[1] 6
[[4]]
[1] 9.5
[[5]]
[1] 2.5