System functions
A system function is a built-in function whose name starts with •, as in •ucs or •json. Type • with Alt-y. Names are case-insensitive. Many system functions take their options as a left argument. A function named for a format reads that format, and its inverse writes it: •json reads JSON, and •json⁻¹ writes it. Each name below links to its page. ]help •name shows the same page. Built-in values have names that start with $, as Constants and $ names describes.
A function that takes one string, such as •json or •element, applies to each string of an array of strings, and to each row of a character matrix, as ⍎ does. A function that takes one number, such as •uuid, applies to each number of an array. The results form an array of the argument’s shape. Results from a character matrix’s rows combine as Rank’s results do. An empty argument gives an empty array of the function’s usual result, such as an empty list of strings from •src. A left argument applies whole to each item. •c, •date, •path and •metadata have their own rules for arrays, which their pages give.
In Python, the workspace object bpl has each system function under its name without •. Options become keyword arguments, as in bpl.json('{"a": null}', fill=0). .undo gives the inverse, as in bpl.json.undo(Y) for •json⁻¹. Python covers the calling conventions.
Random numbers and distributions