A unified conversion utility for binary variables. Converts a logical, numeric, factor, or character vector to a binary numeric vector coded as 0 and 1.
Arguments
- x
a logical, numeric, integer, factor, or character vector.
- pos
optional positive value. If supplied, observations equal to
posare coded as 1 and all others as 0. Must be one of the observed values or factor levels.- warn
logical. If
TRUE(default), a warning is issued when a factor or character vector is coerced to binary without an explicitpos, indicating which value is coded as 1.
Value
a numeric vector of 0s and 1s (and NAs where present in
x). For factor and character input, the result carries a
"coding" attribute, a named integer vector documenting which
original value was mapped to 0 and which to 1.
Details
For logical input, TRUE is mapped to 1 and FALSE
to 0.
For numeric input, values must already be 0 or 1 (or NA);
any other value raises an error.
For factor input, the vector must have exactly two levels. By
default the second level is coded as 1. Use pos to specify which
level should be coded as 1.
For character input, the vector must have exactly two distinct
non-missing values. By default the alphabetically second value is coded
as 1. The same pos logic applies.
See also
Other data.recode:
combLevels(),
dummy(),
mReplace(),
nf(),
recodeX(),
revCode(),
stringsAsFactors()
Examples
# logical
asBinary(c(TRUE, FALSE, TRUE))
#> [1] 1 0 1
# numeric (already binary)
asBinary(c(0, 1, 1, 0))
#> [1] 0 1 1 0
# factor: second level coded as 1 by default
asBinary(factor(c("control", "treatment", "control")))
#> Warning: coercing factor to binary (0/1): using 'treatment' as '1'
#> [1] 0 1 0
#> attr(,"coding")
#> control treatment
#> 0 1
# factor with explicit positive value
asBinary(factor(c("control", "treatment", "control")), pos = "treatment")
#> [1] 0 1 0
#> attr(,"coding")
#> control treatment
#> 0 1
# character
asBinary(c("no", "yes", "no", "yes"))
#> Warning: coercing character to binary (0/1): using 'yes' as '1'
#> [1] 0 1 0 1
#> attr(,"coding")
#> no yes
#> 0 1
# character with explicit positive value
asBinary(c("F", "U", "F", "U"), pos = "F")
#> [1] 1 0 1 0
#> attr(,"coding")
#> U F
#> 0 1