⍕ — Format / Format spec

Function. Keys: Alt-o n. Hanzi: 文. Ranks: ∞ monadic, 1 ∞ dyadic

⍕Y returns character text. Matrix rows remain rows. Numbers that share a marked kind write as display shows them: as their literal laid out in rows, with one mark after the brackets. Each plane of a higher rank is its own bracketed block.

⍕1 2 3             ⍝ "1 2 3"
⍕2 2⍴⍳4ₓ           ⍝ 2 6⍴"[0 1   2 3]ₓ"

D⍕Y gives D decimal places. A negative D gives exponent notation with |D| significant digits.

2⍕3.125 10         ⍝ "3.13 10.00"
¯2⍕1234.5          ⍝ "1.2ₑ3"

An empty D, ⍬ or '', gives ⍕Y‘s text without the markers of numbers’ kinds, such as ₓ.

⍕[1 2 3]ₓ          ⍝ "[1 2 3]ₓ"
⍬⍕[1 2 3]ₓ         ⍝ "1 2 3"
''⍕2 2⍴⍳4ₓ         ⍝ 2 3⍴"0 12 3"

W D⍕Y also sets the field width W. Give one pair per column to set each column separately. Width 0 fits each column to its longest number, with one space between columns. Overflowing fields become *.

6 2⍕3.125          ⍝ "  3.13"

Formatting is independent of REPL boxing.