BUILT-IN WOLFRAM LANGUAGE SYMBOL
is a global variable whose value, if set, is applied to every expression before it is printed.
- $PrePrint is applied after Out[n] is assigned, but before the output result is printed.
By default, $PrePrint is not defined, meaning output is shown as it comes from evaluation:
Show exact quantities by their numerical value:
The function is designed to preserve arbitrary precision numbers if they are in the output:
Restore $PrePrint to the default:
Note that changing $PrePrint did not change the values saved in Out: