Creates a formulas argument

This helper function creates a valid formulas object. The formulas object is an argument to the mice function. It is a list of formula's that specifies the target variables and the predictors by means of the standard ~ operator.

make.formulas(data, blocks = make.blocks(data), predictorMatrix = NULL)

Arguments

data	A data.frame with the source data
blocks	An optional specification for blocks of variables in the rows. The default assigns each variable in its own block.
predictorMatrix	A predictorMatrix specified by the user.

Value

A list of formula's.

See also

make.blocks, make.predictorMatrix

Examples

f1 <- make.formulas(nhanes)
f1
#> $age
#> age ~ 0 + bmi + hyp + chl
#> <environment: 0x7fe182d25318>
#> 
#> $bmi
#> bmi ~ 0 + age + hyp + chl
#> <environment: 0x7fe182d25318>
#> 
#> $hyp
#> hyp ~ 0 + age + bmi + chl
#> <environment: 0x7fe182d25318>
#> 
#> $chl
#> chl ~ 0 + age + bmi + hyp
#> <environment: 0x7fe182d25318>
#> 
f2 <- make.formulas(nhanes, blocks = make.blocks(nhanes, "collect"))
f2
#> $collect
#> age + bmi + hyp + chl ~ 0
#> <environment: 0x7fe182c51e08>
#> 

# for editing, it may be easier to work with the character vector
c1 <- as.character(f1)
c1
#> [1] "age ~ 0 + bmi + hyp + chl" "bmi ~ 0 + age + hyp + chl"
#> [3] "hyp ~ 0 + age + bmi + chl" "chl ~ 0 + age + bmi + hyp"

# fold it back into a formula list
f3 <- name.formulas(lapply(c1, as.formula))
f3
#> $age
#> age ~ 0 + bmi + hyp + chl
#> <environment: 0x7fe1829b09b0>
#> 
#> $bmi
#> bmi ~ 0 + age + hyp + chl
#> <environment: 0x7fe1829b09b0>
#> 
#> $hyp
#> hyp ~ 0 + age + bmi + chl
#> <environment: 0x7fe1829b09b0>
#> 
#> $chl
#> chl ~ 0 + age + bmi + hyp
#> <environment: 0x7fe1829b09b0>
#>