create_quantiles is a parsimonious function for generating quantiles of a vector (e.g., quartiles for num=4 or quintiles for num=5). Basically a wrapper for the cut function; the type of the output is factor. Fails for vectors with overlapping quantiles (e.g., with >50% of values of x equal to zero) unless the correct number of labels (i.e., the number of unique quantile breaks) is given in the labels argument.
to.pct converts a number (probably a proportion, i.e., typically between 0 and 1) to a percentage; also has an argument (dig) which can be used to round the output inline.
nx.mlt returns the least multiple of n which (weakly) exceeds x. Convenient for making axes ticks land on pretty numbers.
divide divides the range (min through max) of x into n points (basically a shorthand for seq).
dol.form takes a financial input and converts it to a (American-formatted, American-currency) string for printing--appending a dollar sign ("\$") and inserting commas after every third digit from the left of the decimal point.
ntostr converts n to a character vector with each element width dig. This is particularly nice for converting 99:100 to "99" and "100".
write.packages captures the current package environment (inspired by sessionInfo() and writes it as a JSON to con with writeLines; a list version of this object is returned. This may be essential for tracking across time which package versions were being used.
stale_package_check reads a file (with readLines) and checks which functions are actually used from each loaded package. Currently only checks for library (i.e., not require) calls.
embed.mat inserts a supplied matrix into a (weakly) larger enclosing matrix, typically filled with 0s, at a specified position.
get_age returns the accurate, fractional age (in years) of each individual, quickly. Accuracy deteriorates when non-leap century years are involved (i.e., any year congruent to 0 mod 100 but not 0 mod 400); designed for use with currently-relevant birthdays and ages.
quick_year converts a Date object into its year efficiently; also ignores concerns of leap centuries. quick_mday returns the day of the month. quick_yday returns the day of the year. Returns as an integer.