Array Lookup - Revision history

Sudleyplace at 20:16, 15 April 2018

2018-04-15T20:16:18Z

← Older revision		Revision as of 16:16, 15 April 2018
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	<p>For example, in origin-1</p>		<p>For example, in origin-1</p>

	<apll>~~      ~~⎕←L←6 4⍴'DinaDickJohnJaneSue Mary~~'<br />~~		<apll><pre>
	Dina~~<br />~~		⎕←L←6 4⍴'DinaDickJohnJaneSue Mary
	Dick~~<br />~~		Dina
	John~~<br />~~		Dick
	Jane~~<br />~~		John
	Sue ~~<br />~~		Jane
	Mary~~<br />~~		Sue
	~~      ~~⎕←R←3 4⍴'JaneBob Sue '<br />		Mary
	Jane~~<br />~~		⎕←R←3 4⍴'JaneBob Sue '<br />
	Bob ~~<br />~~		Jane
	Sue ~~<br />~~		Bob
	~~      ~~L⍸R~~<br />~~		Sue
	4 7 5</apll>		L⍸R
			4 7 5</pre></apll>

	<p>This function was suggested by the language designers of Dyalog APL.</p>		<p>This function was suggested by the language designers of Dyalog APL.</p>

2013-06-16T15:15:15Z

← Older revision		Revision as of 11:15, 16 June 2013
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	<td></td>		<td></td>
	<td></td>		<td></td>
	<td>returns a simple integer vector identical to <apll>(~~⊂⍤(¯1+⍴⍴L)~~ L)⍳⊂⍤(¯1+⍴⍴L) R</apll>.</td>		<td>returns a simple integer vector identical to <apll>(⊂⍤¯1 L)⍳⊂⍤(¯1+⍴⍴L) R</apll>.</td>
	</tr>		</tr>
	</table>		</table>
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	</tr>		</tr>
	<tr>		<tr>
	<td><apll>Z</apll> is an ~~integer vector~~ of ~~length~~ <apll>~~1↑⍴R~~</apll>.</td>		<td><apll>Z</apll> is an array of rank <apll>0⌈1+(⍴⍴R)-⍴⍴L</apll> and shape <apll>(1-⍴⍴L)↓⍴R</apll>.</td>
	</tr>		</tr>
	<tr>		<tr>

2013-05-26T15:23:12Z

← Older revision		Revision as of 11:23, 26 May 2013
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	</tr>		</tr>
	<tr>		<tr>
	<td>For matrices, the result is equivalent to <apll>(⊂[2] L)⍳⊂[2] R</apll> which encapsulates a common idiom in one symbol.</td>		<td>For matrices, the result is equivalent to <apll>(⊂[2] L)⍳⊂[2] R</apll> (lookup the rows of one array in another) which encapsulates a common idiom in one symbol.</td>
	</tr>		</tr>
	<tr>		<tr>
	<td>For higher rank arrays, the arguments are enclosed to become vectors of subarrays and then the usual lookup produces the final result.</td>		<td>For higher rank arrays, the arguments are enclosed to become vectors of subarrays and then the usual lookup produces the final result.</td>
			</tr>
			<tr>
			<td>This function is sensitive to both <apll>⎕IO</apll> and <apll>⎕CT</apll>.</td>
	</tr>		</tr>
	</table>		</table>
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	L⍸R<br />		L⍸R<br />
	4 7 5</apll>		4 7 5</apll>

			<p>This function was suggested by the language designers of Dyalog APL.</p>