SubIndex

SubIndex(A,u,I)

Returns the value from index «I» at which the value «u» is found in array «A». If «u» does not occur in «A», returns Null. If «u» occurs more than once in «A», returns the value in «I» corresponding to the last occurrence of «u».

Library

Array Functions

Array Abstraction

When «A» has more than one dimension, or «u» is an array, SubIndex array abstracts according to the standard rules of array abstraction. For example, when «A» contains an index other than I, SubIndex is applied to each slice of that index, returning the position of «u» in the corresponding slice. When «u» contains an array of values, the position of each of those values in «A» is returned.

Examples

Let:

I → 'a' 'b' 'c' 'd' 'e' 'f' A → 4 3 2 5 3 1

B I 'a' 'b' 'c' 'd' 'e' 'f' J 1 3 5 2 4 5 3 2 2 1 5 2 3 4

K → 1 2 3 4 5 C → 4 2 5 1 3

Then:

SubIndex(A,2,I) → 'c'

SubIndex(A,3,I) → 'e'

SubIndex(A,6,I) → «null»

SubIndex(A,1..5,I) → ['f', 'c', 'e', 'a', 'd']

SubIndex(A,C,I) →

K → 1 2 3 4 5 'a' 'c' 'd' 'f' 'e'

SubIndex(B,2,I) →

J → 1 2 'c' 'd'

SubIndex(B,C,I) →

B K 1 2 3 4 5 J 1 'd' 'c' 'e' «null» 'f' 2 'f' 'd' 'c' 'd' 'e'

See Also

• PositionInIndex