misty (version 0.7.1)

as.na: 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 a user-specified value or character string in the argument na.

Usage

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

Value

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

Arguments

data

a vector, factor, matrix, array, data frame, or list.

...

an expression indicating the variable names in data, e.g., as.na(dat, x1, x2) for selecting the variables x1 and x2 from the data frame dat. Note that the operators ., +, -, ~, :, ::, and ! can also be used to select variables, see 'Details' in the df.subset function.

na

a vector indicating values or characters to replace with NA, or which NA is replaced. Note that a numeric value or character string needs to be specified for the argument na when using na.as.

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.

Author

Takuya Yanagida

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

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

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

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

# Example 2a: Replace "b" with NA
as.na(chr, na = "b")

# Example 2b: Replace "b", "c", and "d" with NA
as.na(chr, na = c("b", "c", "d"))

# Example 2c: 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 3a: Replace "b" with NA
as.na(fac, na = "b")

# Example 3b: Replace "b" and "c" with NA
as.na(fac, na = c("b", "c"))

# Example 3c: Replace NA with "b"
na.as(factor(c("a", "a", NA, NA, "c", "c")), na = "b")

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

# Example 4a: Replace 8 with NA
as.na(mat, na = 8)

# Example 4b: Replace 8, 14, and 20 with NA
as.na(mat, na = c(8, 14, 20))

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

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

# Example 5: Replace 1 and 10 with NA
as.na(array(1:20, dim = c(2, 3, 2)), na = c(1, 10))

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

# Example 6:  Replace 1 with NA
as.na(list(x1 = c(1, 2, 3, 1, 2, 3), x2 = c(2, 1, 3, 2, 1)), na = 1)

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

# Example 7a: Replace 1 with NA
as.na(df, na = 1)

# Example 7b: Replace 1 with NA for the variable x2
as.na(df, x2, na = 1)

# Alternative specification
as.na(df$x2, na = 1)

# Example 7c: Replace 1 and 3 with NA
as.na(df, na = c(1, 3))

# Example 7d: Replace 1 with NA in 'x2' and 'x3'
as.na(df, x2, x3, na = 1)

# Example 7e: Replace NA with -99
na.as(data.frame(x1 = c(NA, 2, 3), x2 = c(2, NA, 3)), na = -99)

# Example 7f: 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)), na = 3, as.na = 30)