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The line is an axis of vertical symmetry in a 2-d context (circle); compare with ⊖, which shows an axis of horizontal symmetry. When applied to a matrix, ⌽ rev
by moonchild 5y ago
The line is an axis of vertical symmetry in a 2-d context (circle); compare with ⊖, which shows an axis of horizontal symmetry. When applied to a matrix, ⌽ reverses rows and ⊖ reverses columns; the elements are mirrored around the pictured axis of symmetry. (In general, when applied to a high-rank array, ⊖ reverses the first axis of its argument, and ⌽ reverses the last.)
- jazzyjackson 5y agoo that's much less esoteric, thanks for the explanation
- beagle3 5y agoThere’s also a circle with a diagonal line through it (on phone, no Unicode keyboard) which consistently with the above axes of symmetry transposes a matrix; don’t remember if it transposes first two or last two axes on higher rank arrays.
- moonchild 5y agoIt reverses the order of the axes. There is also a dyadic variant, which provides a new order for the axes. Duplicating an axis is no problem; but there is a danger of leaving out an axis. So in j, instead, the specified axes are moved to the rear.
- moonchild 5y ago(Axes of horizontal and vertical symmetry, respectively, of course; I don't know why I wrote that.)