The fapply function applies formatting to a vector.
fapply(x, format = NULL, width = NULL, justify = NULL)A vector, factor, or list to apply the format to.
A format to be applied.
The desired character width of the formatted vector. Default value is NULL, meaning the vector will be variable width.
Whether to justify the return vector. Valid values are 'left', 'right', 'center', 'centre', or 'none'.
A vector of formatted values.
The fapply function accepts several types of formats: formatting
strings, named vectors,
vectorized functions, or user-defined formats. It also
accepts a formatting list, composed of any of the previous types.
The function will first determine the type of format, and then apply
the format in the appropriate way. Results are returned as a vector.
The function also has parameters for width and justification.
Parameters may also be passed as attributes on the vector. See
the fattr function for additional information on setting
formatting attributes.
The fapply function will process any of the following types of
formats:
Formatting string: A single string will be interpreted as a formatting string. See the FormattingStrings documentation for further details.
Named vector: A named vector can serve as a lookup list or decode for a vector. You can use a named vector to perform simple lookups on character vectors.
Format object: A format object may be created using the
value function. The format object is included in the
fmtr package, and is specially designed for data categorization.
Vectorized formatting function: A vectorized function
provides
the most flexibility and power over your formatting. You can use
an existing formatting function from any package, or create
your own vectorized formatting function using Vectorize.
"best" format name: A "best" format name of the form "bestW", where "W" is the desired width. The "best" format replicates the SAS format of the same name. See section below for further information.
fapply will also accept a formatting list, which can contain any
number of formats from the above list. To create a formatting list,
see the flist function.
The SAS "best" format is used to fit numeric values within a certain width. The word "best" is followed by the desired width, i.e. "best6" or "best12". The format will then use the most optimal display for the available width.
The format will use the entire value if the number of digits fits in the desired width. If not, the format may round the value. The format may also use scientific notation if the value is very large or very small. If the format cannot fit the value in the desired width at all, it will emit stars ("*") in the desired width.
For input values that are less than the desired width, the result will be left-padded with spaces. The output value will then always contain the exact number of characters requested.
Such a format has no direct equivalent in R, and is indeed difficult to replicate. For this reason, the fmtr package added this format option for those situations when you want to replicate SAS "best" formatting as closely as possible.
The "best" format accepts widths between 1 and 32. The default width is 12. The R "best" format syntax does not accept a number of decimals, as in "bestW.d".
Note that "best" widths between 8 and 16 will match SAS most reliably. Small widths have many special cases, and the logic is difficult to replicate. For large values, there are some differences between SAS and R in how they represent these numbers, and sometimes they will not match.
## Example 1: Formatting string ##
v1 <- c(1.235, 8.363, 5.954, 2.465)
# Apply string format.
fapply(v1, "%.1f")
# [1] "1.2" "8.4" "6.0" "2.5"
# Apply width and two decimals
fapply(v1, "%5.2f")
# [1] " 1.24" " 8.36" " 5.95" " 2.46"
# Apply "best" format
fapply(v1, "best3")
# [1] "1.2" "8.4" " 6" "2.5"
## Example 2: Named vector ##
# Set up vector
v2 <- c("A", "B", "C", "B")
# Set up named vector for formatting
fmt2 <- c(A = "Label A", B = "Label B", C = "Label C")
# Apply format to vector
fapply(v2, fmt2)
# [1] "Label A" "Label B" "Label C" "Label B"
## Example 3: User-defined format ##
# Define format
fmt3 <- value(condition(x == "A", "Label A"),
condition(x == "B", "Label B"),
condition(TRUE, "Other"))
# Apply format to vector
fapply(v2, fmt3)
# [1] "Label A" "Label B" "Other" "Label B"
## Example 4: Formatting function ##
# Set up vectorized function
fmt4 <- Vectorize(function(x) {
if (x %in% c("A", "B"))
ret <- paste("Label", x)
else
ret <- "Other"
return(ret)
})
# Apply format to vector
fapply(v2, fmt4)
# [1] "Label A" "Label B" "Other" "Label B"
## Example 5: Formatting List - Row Type ##
# Set up data
# Notice each row has a different data type
v3 <- list(2841.258, "H", Sys.Date(),
"L", Sys.Date() + 60, 1382.8865)
v4 <- c("int", "char", "date", "char", "date", "int")
# Create formatting list
lst <- flist(type = "row", lookup = v4,
int = function(x) format(x, digits = 2, nsmall = 1,
big.mark=","),
char = value(condition(x == "H", "High"),
condition(x == "L", "Low"),
condition(TRUE, "NA")),
date = "%d%b%Y")
# Apply formatting list to vector
fapply(v3, lst)
# [1] "2,841.3" "High" "06Jan2024" "Low" "06Mar2024" "1,382.9"
## Example 6: Formatting List - Column Type ##
# Set up data
v5 <- c(Sys.Date(), Sys.Date() + 30, Sys.Date() + 60)
v5
# [1] "2024-01-06" "2024-02-05" "2024-03-06"
# Create formatting list
lst <- flist("%B", "This month is: %s", type = "column")
# Apply formatting list to vector
fapply(v5, lst)
# [1] "This month is: January" "This month is: February" "This month is: March"
# Example 7: Conditional Formatting
# Data vector
v6 <- c(8.38371, 1.46938, 3.28783, NA, 0.98632)
# User-defined format
fmt5 <- value(condition(is.na(x), "Missing"),
condition(x < 1, "Low"),
condition(x > 5, "High"),
condition(TRUE, "%.2f"))
# Apply format to data vector
fapply(v6, fmt5)
# [1] "High" "1.47" "3.29" "Missing" "Low"
# Example 8: "best" Format
#' # Data vector
v7 <- c(12.3456, 1234567.89, NA, 0.123456, 0.000012345)
fapply(v7, "best6")
# [1] "12.346" "1.23E6" NA "0.1235" "123E-7"