Search results
Results From The WOW.Com Content Network
A two-dimensional array, in particular, would be implemented as a vector of pointers to its rows. Thus an element in row i and column j of an array A would be accessed by double indexing (A[i][j] in typical notation). This way of emulating multi-dimensional arrays allows the creation of jagged arrays, where each row may have a different size ...
In modern JavaScript it's considered bad form to use the Array type as an associative array. Consensus is that the Object type and Map / WeakMap classes are best for this purpose. The reasoning behind this is that if Array is extended via prototype and Object is kept pristine, for and for-in loops will work as expected on associative 'arrays'.
For example, to perform an element by element sum of two arrays, a and b to produce a third c, it is only necessary to write c = a + b In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine. For example, if x is an array, then y = sin (x)
Matrix multiplication is an example of a 2-rank function, because it operates on 2-dimensional objects (matrices). Collapse operators reduce the dimensionality of an input data array by one or more dimensions. For example, summing over elements collapses the input array by 1 dimension.
APL for PCs, Servers and Tablets - NARS full-featured, no restrictions, free downloadable APL/2 with nested arrays by Sudley Place Software; GNU APL free downloadable interpreter for APL by Jürgen Sauermann; YouTube APL Tutorials uploaded by Jimin Park, 8 intro/beginner instructional videos. SIGAPL Compiled Tutorials List
For example, the iota function (ι) can replace for-loop iteration: ιN when applied to a scalar positive integer yields a one-dimensional array (vector), 1 2 3 ... N. N. Later APL implementations generally include comprehensive control structures, so that data structure and program control flow can be clearly and cleanly separated.
A = round (rand (3, 4, 5) * 10) % 3x4x5 three-dimensional or cubic array > A (:,:, 3) % 3x4 two-dimensional array along first and second dimensions ans = 8 3 5 7 8 9 1 4 4 4 2 5 > A (:, 2: 3, 3) % 3x2 two-dimensional array along first and second dimensions ans = 3 5 9 1 4 2 > A (2: end,:, 3) % 2x4 two-dimensional array using the 'end' keyword ...
A matrix is typically stored as a two-dimensional array. Each entry in the array represents an element a i,j of the matrix and is accessed by the two indices i and j. Conventionally, i is the row index, numbered from top to bottom, and j is the column index, numbered from left to right.