Integer or vector of integers specifying the number of decimals
to round x=. When vector is passed, each integer is mapped 1:1 to the
numeric values in x
big.mark
Character used between every 3 digits to separate
hundreds/thousands/millions/etc.
Default is ",", except when decimal.mark = "," when the default is a space.
decimal.mark
The character to be used to indicate the numeric decimal point.
Default is "." or getOption("OutDec")
scale
A scaling factor: x will be multiplied by scale before formatting.