Y must be a simple real (non-complex) numeric array. X must be a simple integer scalar or vector. R is a character array displaying the array Y according to the specification X. R has rank 1⌈⍴⍴Y and ¯1↓⍴R is ¯1↓⍴Y. If any element of Y is complex, dyadic ⍕ reports a DOMAIN ERROR.
Conformability requires that if X has more than two elements, then ⍴X must be 2ׯ1↑⍴Y. If X contains one element, it is extended to (2ׯ1↑⍴Y)⍴0,X. If X contains 2 elements, it is extended to (2ׯ1↑⍴Y)⍴X.
X specifies two numbers (possibly after extension) for each column in Y. For this purpose, scalar Y is treated as a one-element vector. Each pair of numbers in X identifies a format width (W) and a format precision (P).
If P is 0, the column is to be formatted as integers.
5 0 ⍕ 2 3⍴⍳6 1 2 3 4 5 6 4 0⍕1.1 2 ¯4 2.547 1 2 ¯4 3
If P is positive, the format is floating point with P significant digits to be displayed after the decimal point.
4 1⍕1.1 2 ¯4 2.547 1.1 2.0¯4.0 2.5
If P is negative, scaled format is used with |P digits in the mantissa.
7 ¯3⍕5 15 155 1555 5.00E0 1.50E1 1.55E2 1.56E3
If W is 0 or absent, then the width of the corresponding columns of R are determined by the maximum width required by any element in the corresponding columns of Y, plus one separating space.
3⍕2 3⍴10 15.2346 ¯17.1 2 3 4 10.000 15.235 ¯17.100 2.000 3.000 4.000
If a formatted element exceeds its specified field width when W>0, the field width for that element is filled with asterisks.
3 0 6 2 ⍕ 3 2⍴10.1 15 1001 22.357 101 1110.1 10 15.00 *** 22.36 101******
If the format precision exceeds the internal precision, low order digits are replaced by the symbol '_'.
26⍕2*100 1267650600228229_______________.__________________________ ⍴26⍕2*100 59 0 20⍕÷3 0.3333333333333333____ 0 ¯20⍕÷3 3.333333333333333____E¯1
The shape of R is the same as the shape of Y except that the last dimension of R is the sum of the field widths specified in X or deduced by the function. If Y is a scalar, the shape of R is the field width.
⍴5 2 ⍕ 2 3 4⍴⍳24 2 3 20