Indexing
From NARS2000
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L is a nested array of integer scalars and/or vectors, suitable for indexing R. | ||||||||
R is an arbitrary array. | ||||||||
A is an arbitrary array. | ||||||||
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Both Reach and Scatter indexing may appear together within a single instance of R[L], R[L]←A, and R[L]f←A | ||||||||
These functions are sensitive to ⎕IO. |
For example, in origin-1
V←'123'(⊂4 5)
V[1 (2 ⍬ 1)]
123 4
M←2 2⍴(10 20) (30 40 'abc') 50 60
M[(1 1)((1 2) 3)]
10 20 abc
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For all but transpose, L is a nested array of integer scalars and/or vectors, suitable for indexing R; for transpose, L is an integer scalar or vector of integers, suitable for transposing R. | ||||
That is, if the largest allowed value for L is N, then the previous allowable range of values was ⎕IO to N, inclusive. Now, the allowable range of values is 1 ¯1[1]-N to N, inclusive. For example, A, A[⍳⍴A], A[⍳-⍴A], and even A[⍳¯1 1[?(⍴⍴A)⍴2]×⍴A] are all identical for any array A in either origin. Also, A, (⍳⍴⍴A)⍉A, and (⍳-⍴⍴A)⍉A are all identical for any array A in either origin. |
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R is an arbitrary array. | ||||
A is an arbitrary array. | ||||
These functions are sensitive to ⎕IO. |
For example, in origin-1
V←'123'(⊂4 5)
V[¯1 (0 ⍬ ¯1)]
123 4