Table: Difference between revisions
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{{Built-in|Table|⍪}}, or '''Ravel Items''', is a [[monadic]] [[primitive function]] which returns a [[matrix]] formed by applying [[Ravel]] to each [[major cell]] of the given array. Table shares its [[glyph]] <source lang=apl inline>⍪</ | {{Built-in|Table|⍪}}, or '''Ravel Items''', is a [[monadic]] [[primitive function]] which returns a [[matrix]] formed by applying [[Ravel]] to each [[major cell]] of the given array. Table shares its [[glyph]] <source lang=apl inline>⍪</syntaxhighlight> with the dyadic function [[catenate|Catenate First]]. | ||
== Examples == | == Examples == | ||
| Line 25: | Line 25: | ||
│MNOPQRSTUVWX│ │ | │MNOPQRSTUVWX│ │ | ||
└────────────┴────┘ | └────────────┴────┘ | ||
</ | </syntaxhighlight> | ||
A [[scalar]] [[argument]] is converted to a 1-by-1 matrix: | A [[scalar]] [[argument]] is converted to a 1-by-1 matrix: | ||
| Line 34: | Line 34: | ||
│123│1 1│ | │123│1 1│ | ||
└───┴───┘ | └───┴───┘ | ||
</ | </syntaxhighlight> | ||
== Properties == | == Properties == | ||
| Line 51: | Line 51: | ||
ABCDEFGHIJKLMNOPQRSTUVWX | ABCDEFGHIJKLMNOPQRSTUVWX | ||
YZABCDEFGHIJKLMNOPQRSTUV | YZABCDEFGHIJKLMNOPQRSTUV | ||
</ | </syntaxhighlight> | ||
In languages where the [[Rank (operator)|Rank operator]] is available, Table is equivalent to <source lang=apl inline>,⍤¯1</ | In languages where the [[Rank (operator)|Rank operator]] is available, Table is equivalent to <source lang=apl inline>,⍤¯1</syntaxhighlight>: | ||
<source lang=apl> | <source lang=apl> | ||
(,⍤¯1)2 3 4 2⍴⎕A | (,⍤¯1)2 3 4 2⍴⎕A | ||
ABCDEFGHIJKLMNOPQRSTUVWX | ABCDEFGHIJKLMNOPQRSTUVWX | ||
YZABCDEFGHIJKLMNOPQRSTUV | YZABCDEFGHIJKLMNOPQRSTUV | ||
</ | </syntaxhighlight> | ||
In languages where [[function axis]] is available, Table is equivalent to <source lang=apl inline>,[1↓⍳≢⍴Y]</ | In languages where [[function axis]] is available, Table is equivalent to <source lang=apl inline>,[1↓⍳≢⍴Y]</syntaxhighlight>: | ||
<source lang=apl> | <source lang=apl> | ||
{,[1↓⍳≢⍴⍵]⍵}2 3 4 2⍴⎕A | {,[1↓⍳≢⍴⍵]⍵}2 3 4 2⍴⎕A | ||
ABCDEFGHIJKLMNOPQRSTUVWX | ABCDEFGHIJKLMNOPQRSTUVWX | ||
YZABCDEFGHIJKLMNOPQRSTUV | YZABCDEFGHIJKLMNOPQRSTUV | ||
</ | </syntaxhighlight> | ||
== External links == | == External links == | ||
Revision as of 10:49, 11 September 2022
⍪
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Table (⍪), or Ravel Items, is a monadic primitive function which returns a matrix formed by applying Ravel to each major cell of the given array. Table shares its glyph <source lang=apl inline>⍪</syntaxhighlight> with the dyadic function Catenate First.
Examples
For arrays of rank 1 or higher, the result is identical to applying Ravel to major cells:
<source lang=apl>
{⍵(⍴⍵)}⍪5⍴⎕A
┌─┬───┐ │A│5 1│ │B│ │ │C│ │ │D│ │ │E│ │ └─┴───┘
{⍵(⍴⍵)}⍪3 4⍴⎕A
┌────┬───┐ │ABCD│3 4│ │EFGH│ │ │IJKL│ │ └────┴───┘
{⍵(⍴⍵)}⍪2 3 4⍴⎕A
┌────────────┬────┐ │ABCDEFGHIJKL│2 12│ │MNOPQRSTUVWX│ │ └────────────┴────┘ </syntaxhighlight>
A scalar argument is converted to a 1-by-1 matrix:
<source lang=apl>
{⍵(⍴⍵)}⍪123
┌───┬───┐ │123│1 1│ └───┴───┘ </syntaxhighlight>
Properties
Table preserves the array's Tally (the number of major cells).
Table is equivalent to reshaping with the shape where all trailing axis lengths have been replaced by their product or, alternatively, the tally concatenated to the bound divided by the tally: <source lang=apl>
⍪2 3 4 2⍴⎕A
ABCDEFGHIJKLMNOPQRSTUVWX YZABCDEFGHIJKLMNOPQRSTUV
{⍵⍴⍨(≢⍵),(×/⍴⍵)÷≢⍵}2 3 4 2⍴⎕A
ABCDEFGHIJKLMNOPQRSTUVWX YZABCDEFGHIJKLMNOPQRSTUV
{⍵⍴⍨(1↑⍴⍵),(×/1↓⍴⍵)}2 3 4 2⍴⎕A
ABCDEFGHIJKLMNOPQRSTUVWX YZABCDEFGHIJKLMNOPQRSTUV </syntaxhighlight>
In languages where the Rank operator is available, Table is equivalent to <source lang=apl inline>,⍤¯1</syntaxhighlight>: <source lang=apl>
(,⍤¯1)2 3 4 2⍴⎕A
ABCDEFGHIJKLMNOPQRSTUVWX YZABCDEFGHIJKLMNOPQRSTUV </syntaxhighlight> In languages where function axis is available, Table is equivalent to <source lang=apl inline>,[1↓⍳≢⍴Y]</syntaxhighlight>: <source lang=apl>
{,[1↓⍳≢⍴⍵]⍵}2 3 4 2⍴⎕A
ABCDEFGHIJKLMNOPQRSTUVWX YZABCDEFGHIJKLMNOPQRSTUV </syntaxhighlight>
External links
Lessons
Documentation