Format

is an ambivalent primitive function which formats the right argument into a simple character array, optionally following the specification supplied as the left argument. The usage of the left argument varies across implementations.

Monadic form
Format in its monadic form allows the user to convert arrays of any type into simple character arrays (for example for concatenation with other character arrays). The result usually matches the interpreter's default display, either by  or by REPL.

Dyadic form
The dyadic form of Format varies across implementations.

Dyalog APL and NARS2000 support column width and the number of decimal places for formatting numeric arrays. The following example formats the 2-by-3 array with 12 spaces per column, rounded to 2 decimal places:

APLX supports Format by example, which uses string left argument for a rich set of format specifications:

Tutorials

 * APL Cultivation

Documentation

 * Dyalog monadic, dyadic
 * NARS2000
 * APLX monadic, by specification, by example
 * J Dictionary, NuVoc