The goal:
to create a function modeled after `subset` (notorious for its non-standard
evaluation) that will take a series of logical tests as unqiuoted expressions
to be evaluated in the framework of a dataframe environment and return a
dataframe of logicals:
mtest.data.frame <-
function (x, ..., drop=FALSE)
{ tests <- list(...); print(tests)
r <- if (length(tests)==0)
stop("no 'tests'")
else { cbind.data.frame(
lapply( tests, function(t){
e <- substitute(t)
r <- eval(e, x, parent.frame() )
if ( !is.logical(r) ) {
stop("'tests' must be logical") }
r & !is.na(r) } ) )
}
}
#--------------
testdata <- structure(list(group1 = structure(1:7, .Label = c("Group A",
"Group B", "Group C", "Group D", "Group E", "Group F", "Group G"
), class = "factor"), group2 = structure(c(3L, 3L, 2L, 1L, 1L,
2L, 3L), .Label = c("LS", "SS", "UNC"), class = "factor"), valid1 =
structure(c(2L,
1L, NA, 1L, 2L, 2L, 1L), .Label = c("N", "Y"), class = "factor"),
valid2 = structure(c(1L, 1L, 2L, 1L, 1L, 2L, 1L), .Label = c("N",
"Y"), class = "factor"), valid3 = structure(c(4L, 3L, NA,
2L, 1L, NA, 5L), .Label = c("0.3", "0.7", "1.2", "1.4", "1.7"
), class = "factor"), valid4 = structure(c(2L, 1L, 3L, 4L,
1L, 1L, 5L), .Label = c("0.3", "0.4", "0.53", "0.66", "0.71"
), class = "factor"), valid5 = structure(c(4L, 1L, NA, NA,
3L, NA, 2L), .Label = c("11.2", "11.7", "8.3", "8.5"), class = "factor")),
.Names = c("group1",
"group2", "valid1", "valid2", "valid3", "valid4", "valid5"), row.names = c(NA,
-7L), class = "data.frame")
#######
> mtest.data.frame(testdata, valid2=="N", valid3 > 1)
[[1]]
[1] "tests are"
[[2]]
[1] TRUE TRUE FALSE TRUE TRUE FALSE TRUE
[[3]]
[1] TRUE TRUE NA FALSE FALSE NA TRUE
This actually seemed to be somewhat successful, but when ...
Now if I take out the `print()` call for 'tests', I get an different answer:
> mtest.data.frame <-
+ function (x, ..., drop=FALSE)
+ { tests <- list(...)
+ r <- if (length(tests)==0)
+ stop("no 'tests'")
+ else { cbind.data.frame(
+ lapply( tests, function(t){
+ e <- substitute(t)
+ r <- eval(e, x, parent.frame() )
+ if ( !is.logical(r) ) {
+ stop("'tests' must be logical") }
+ r & !is.na(r) } ) )
+ }
+ }
> mtest.data.frame(testdata, valid2=="N", valid3 > 1)
> # i.e. no answer
--
David Winsemius
Alameda, CA, USA
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