Description Usage Arguments Examples
foreach
evaluates an expression given as second argument by substituting
in variables. The expression may also contain assignments, which take effect in
the callers environment.
1 |
... |
tagged and untagged arguments. The tagged arguments define the 'variables' that are looped over, the first untagged argument defines the expression wich is evaluated. |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | x <- 1:3
y <- -(1:3)
z <- c("Uri","Schwyz","Unterwalden")
print(x)
print(y)
print(z)
foreach(var=c(x,y,z), # assigns names
names(var) <- letters[1:3] # to the elements of x, y, and z
)
print(x)
print(y)
print(z)
ds <- data.set(
a = c(1,2,3,2,3,8,9),
b = c(2,8,3,2,1,8,9),
c = c(1,3,2,1,2,8,8)
)
print(ds)
ds <- within(ds,{
description(a) <- "First item in questionnaire"
description(b) <- "Second item in questionnaire"
description(c) <- "Third item in questionnaire"
wording(a) <- "What number do you like first?"
wording(b) <- "What number do you like second?"
wording(c) <- "What number do you like third?"
foreach(x=c(a,b,c),{ # Lazy data documentation:
labels(x) <- c( # a,b,c get value labels in one statement
one = 1,
two = 2,
three = 3,
"don't know" = 8,
"refused to answer" = 9)
missing.values(x) <- c(8,9)
})
})
as.data.frame(ds)
ds <- within(ds,foreach(x=c(a,b,c),{
measurement(x) <- "interval"
}))
as.data.frame(ds)
|
Loading required package: lattice
Loading required package: MASS
Attaching package: ‘memisc’
The following objects are masked from ‘package:stats’:
contr.sum, contr.treatment, contrasts
The following object is masked from ‘package:base’:
as.array
[1] 1 2 3
[1] -1 -2 -3
[1] "Uri" "Schwyz" "Unterwalden"
a b c
1 2 3
a b c
-1 -2 -3
a b c
"Uri" "Schwyz" "Unterwalden"
a b c
1 1 2 1
2 2 8 3
3 3 3 2
4 2 2 1
5 3 1 2
6 8 8 8
7 9 9 8
a b c
1 1 2 1
2 2 NA 3
3 3 3 2
4 2 2 1
5 3 1 2
6 NA NA NA
7 NA NA NA
a b c
1 1 2 1
2 2 NA 3
3 3 3 2
4 2 2 1
5 3 1 2
6 NA NA NA
7 NA NA NA
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