trusted
183
edits
Subarray: Difference between revisions
Jump to navigation
Jump to search
no edit summary
m (Array relationships category) |
No edit summary |
||
| Line 1: | Line 1: | ||
:''The term sub-array may also be used to refer to an array [[cell]].'' | :''The term sub-array may also be used to refer to an array [[cell]].'' | ||
A '''subarray''' (or '''sub-array''') of an array is another array which can be formed by selecting a contiguous section along each [[axis]]. The subarrays of an array are all those that result from [[indexing]] that array by a full set of [[index]] arrays each of which is either a [[scalar]] or a [[vector]] of sequential indices. The term subarray is used loosely in APL and rarely defined directly. Depending on context, scalar indices may be allowed only for [[Axis ordering|leading]] axes or not at all. If scalar indices are not allowed than a subarray shares every [[axis]] with the array that contains it and has equal [[rank]] to it; we might call such subarrays ''equal-rank'' subarrays. Otherwise a subarray has rank less than or equal to its containing array. | A '''subarray''' (or '''sub-array''') of an array is another array which can be formed by selecting a contiguous section along each [[axis]]. The subarrays of an array are all those that result from [[Bracket indexing|indexing]] that array by a full set of [[index]] arrays each of which is either a [[scalar]] or a [[vector]] of sequential indices. The term subarray is used loosely in APL and rarely defined directly. Depending on context, scalar indices may be allowed only for [[Axis ordering|leading]] axes or not at all. If scalar indices are not allowed than a subarray shares every [[axis]] with the array that contains it and has equal [[rank]] to it; we might call such subarrays ''equal-rank'' subarrays. Otherwise a subarray has rank less than or equal to its containing array. | ||
A vector subarray of a [[vector]] is a subvector. In languages outside of the APL family which have only 1-dimensional arrays, "subarray" may have this meaning: for example, the [[wikipedia:maximum subarray problem|maximum subarray problem]] is usually taken to apply to 1-dimensional arrays only. The term "slice" may also be used to refer to a subvector outside of APL. | A vector subarray of a [[vector]] is a subvector. In languages outside of the APL family which have only 1-dimensional arrays, "subarray" may have this meaning: for example, the [[wikipedia:maximum subarray problem|maximum subarray problem]] is usually taken to apply to 1-dimensional arrays only. The term "slice" may also be used to refer to a subvector outside of APL. | ||