[英]Function list over a list of data frames without nesting apply()
使用下面的數據dat
,我正在嘗試獲得以下結果,僅不進行嵌套
lapply(, sapply...)
,如下所示。
> lapply(dat, function(x) sapply(funs, function(y) y(x)))
# $bondsba01
# AVG SLG
# 0.223 0.300
#
# $pujolal01
# AVG SLG
# 0.329 0.422
我對rapply()
很熟悉,但是在此列表上實現它時遇到了麻煩。 我認為,由於dat
是數據幀列表,因此此調用相當於一個列表列表,並且rapply
是合適的。
我嘗試了rapply()
的一些變體,並且幾乎每次都遇到相同的錯誤。
> rapply(funs, function(x) x(dat), how = "replace")
# Error in eval(expr, envir, enclos) : object 'H' not found
當how = "list"
和how = "unlist"
時,出現相同的錯誤, how = "list"
在不將sapply
與lapply
嵌套的情況下執行此lapply
?
樣本數據:
dat <-
structure(list(bondsba01 = structure(list(AB = 413L, R = 72L,
H = 92L, X2B = 26L, X3B = 3L, HR = 16L, RBI = 48L, SB = 36L,
CS = 7L, BB = 65L, SO = 102L, IBB = 2L, HBP = 2L, SH = 2L,
SF = 2L), .Names = c("AB", "R", "H", "X2B", "X3B", "HR",
"RBI", "SB", "CS", "BB", "SO", "IBB", "HBP", "SH", "SF"), row.names = 1L,
class = "data.frame"),
pujolal01 = structure(list(AB = 590L, R = 112L, H = 194L,
X2B = 47L, X3B = 4L, HR = 37L, RBI = 130L, SB = 1L, CS = 3L,
BB = 69L, SO = 93L, IBB = 6L, HBP = 9L, SH = 1L, SF = 7L),
.Names = c("AB", "R", "H", "X2B", "X3B", "HR", "RBI", "SB", "CS", "BB",
"SO", "IBB", "HBP", "SH", "SF"), row.names = 1L, class = "data.frame")),
.Names = c("bondsba01", "pujolal01"))
功能列表:
funs <-
structure(list(AVG = function (x)
with(x, round(H/AB, 3)), SLG = function (x)
with(x, round(((H - X2B - X3B - HR) + 2 * X2B + 3 * X3B + HR)/AB,
3))), .Names = c("AVG", "SLG"))
鏈接到實際數據 。
僅僅因為它是星期六的早晨,並且我想嘗試使用foreach
,所以這里有一個解決方案:
library(foreach)
library(iterators)
foreach(x=iter(dat), .combine=cbind) %:%
foreach(f=iter(funs), .combine=c) %do%
f(x)
result.1 result.2
[1,] 0.223 0.329
[2,] 0.300 0.422
這應該很快,但是更重要的是,並行化foreach非常容易。 您只需要進行兩項更改:
doParallel
)並注冊集群 %do%
更改為%dopar%
像這樣:
library(doParallel)
cl <- makePSOCKcluster(2)
registerDoParallel(cl)
foreach(x=iter(dat), .combine=cbind) %:%
foreach(f=iter(funs), .combine=c) %dopar%
f(x)
result.1 result.2
[1,] 0.223 0.329
[2,] 0.300 0.422
stopCluster(cl)
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