as.na {misty}

Replace User-Specified Values With Missing Values or Missing Values With User-Specified Values

Description

The function as.na replaces user-specified values in the argument na in a vector, factor, matrix, array, list, or data frame with NA, while the function na.as replaces NA in a vector, factor, matrix or data frame with user-specified values in the argument na.

Usage

as.na(..., data = NULL, na, replace = TRUE, check = TRUE)

na.as(..., data = NULL, na, replace = TRUE, as.na = NULL, check = TRUE)

Arguments

...

a vector, factor, matrix, array, data frame, or list. Alternatively, an expression indicating the variable names in data e.g., as.na(x1, x2, data = dat). Note that the operators ., +, -, ~, :, ::, and ! can be used to select variables, see 'Details' in the df.subset function.

data

a data frame when specifying one or more variables in the argument .... Note that the argument is NULL when specifying a vector, factor, matrix, array, data frame, or list for the argument ....

na

a vector indicating values or characters to replace with NA, or which NA is replaced.

replace

logical: if TRUE (default), variable(s) specified in ... are replaced in the argument data.

check

logical: if TRUE (default), argument specification is checked.

as.na

a numeric vector or character vector indicating user-defined missing values, i.e. these values are converted to NA before conducting the analysis.

Value

Returns a vector, factor, matrix, array, data frame, or list specified in the argument ... or a data frame specified in data with variables specified in ... replaced.

Author(s)

Takuya Yanagida [e-mail]

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

na.auxiliary, na.coverage, na.descript, na.indicator, na.pattern, na.prop, na.test

Examples

#-------------------------------------------------------------------------------
# Numeric vector
num <- c(1, 3, 2, 4, 5)

# Example 1: Replace 2 with NA
as.na(num, na = 2)

# Example 2: Replace 2, 3, and 4 with NA
as.na(num, na = c(2, 3, 4))

# Example 3: Replace NA with 2
na.as(c(1, 3, NA, 4, 5), na = 2)

#-------------------------------------------------------------------------------
# Character vector
chr <- c("a", "b", "c", "d", "e")

# Example 4: Replace "b" with NA
as.na(chr, na = "b")

# Example 5: Replace "b", "c", and "d" with NA
as.na(chr, na = c("b", "c", "d"))

# Example 6: Replace NA with "b"
na.as(c("a", NA, "c", "d", "e"), na = "b")

#-------------------------------------------------------------------------------
# Factor
fac <- factor(c("a", "a", "b", "b", "c", "c"))

# Example 7: Replace "b" with NA
as.na(fac, na = "b")

# Example 8: Replace "b" and "c" with NA
as.na(fac, na = c("b", "c"))

# Example 9: Replace NA with "b"
na.as(factor(c("a", "a", NA, NA, "c", "c")), na = "b")

#-------------------------------------------------------------------------------
# Matrix
mat <- matrix(1:20, ncol = 4)

# Example 10: Replace 8 with NA
as.na(mat, na = 8)

# Example 11: Replace 8, 14, and 20 with NA
as.na(mat, na = c(8, 14, 20))

# Example 12: Replace NA with 2
na.as(matrix(c(1, NA, 3, 4, 5, 6), ncol = 2), na = 2)

#-------------------------------------------------------------------------------
# Array

# Example 13: Replace 1 and 10 with NA
as.na(array(1:20, dim = c(2, 3, 2)), na = c(1, 10))

#-------------------------------------------------------------------------------
# List

# Example 14:  Replace 1 with NA
as.na(list(x1 = c(1, 2, 3, 1, 2, 3),
           x2 = c(2, 1, 3, 2, 1),
           x3 = c(3, 1, 2, 3)), na = 1)

#-------------------------------------------------------------------------------
# Data frame
df <- data.frame(x1 = c(1, 2, 3),
                 x2 = c(2, 1, 3),
                 x3 = c(3, 1, 2))

# Example 15a: Replace 1 with NA
as.na(df, na = 1)

# Example 15b: Alternative specification using the 'data' argument
as.na(., data = df, na = 1)

# Example 16: Replace 1 and 3 with NA
as.na(df, na = c(1, 3))

# Example 17a: Replace 1 with NA in 'x2'
as.na(df$x2, na = 1)

# Example 17b: Alternative specification using the 'data' argument
as.na(x2, data = df, na = 1)

# Example 18: Replace 1 with NA in 'x2' and 'x3'
as.na(x2, x3, data = df, na = 1)

# Example 19: Replace 1 with NA in 'x1', 'x2', and 'x3'
as.na(x1:x3, data = df, na = 1)

# Example 20: Replace NA with -99
na.as(data.frame(x1 = c(NA, 2, 3),
                 x2 = c(2, NA, 3),
                 x3 = c(3, NA, 2)), na = -99)

# Example 2: Recode by replacing 30 with NA and then replacing NA with 3
na.as(data.frame(x1 = c(1, 2, 30),
                 x2 = c(2, 1, 30),
                 x3 = c(30, 1, 2)), na = 3, as.na = 30)