Format Catalogs

2021-11-17

The fcat() function

As of fmtr version 1.2, you can now create a format catalog. A format catalog is a collection of formats that can be saved, shared, and reused. The format catalog is created with the fcat() function. A format catalog can also be converted to and from a data frame using the as.data.frame() and as.fcat() functions. These functions make it easy to store formatting information as tabular metadata, such as in database tables or Excel spreadsheets. Here is an example:

# Create format catalog
c1 <- fcat(num_fmt  = "%.1f",
           label_fmt = value(condition(x == "A", "Label A"),
                             condition(x == "B", "Label B"),
                             condition(TRUE, "Other")),
           date_fmt = "%d%b%Y")
 
# Use formats in the catalog
fapply(2, c1$num_fmt)
# [1] "2.0"

fapply(c("A", "B", "C", "B"), c1$label_fmt)
# [1] "Label A" "Label B" "Other"   "Label B"

fapply(Sys.Date(), c1$date_fmt)
# [1] "22Jul2021"

# Convert to a data frame
dat <- as.data.frame(c1)
dat
#        Name Type Expression   Label Order
# 1   num_fmt    S       %.1f            NA
# 2 label_fmt    U   x == "A" Label A    NA
# 3 label_fmt    U   x == "B" Label B    NA
# 4 label_fmt    U       TRUE   Other    NA
# 5  date_fmt    S     %d%b%Y            NA

# Save format catalog for later use
write.fcat(c1, tempdir())

Next: Convenience Functions