ABSTRACT
This chapter introduces a variety of A Programming Language (APL) functions for manipulating arrays. They are take, drop, ravel, replicate, expansion, reverse, rotate, dyadic transpose, and laminate. These functions are used for selecting subarrays out of an array, filling out arrays, or rearranging data within arrays. The monadic use of a comma provides a function that strings out all of the data in a given array as a vector. The monadic APL function reverse, denoted ϕ is used to reverse the order of the entries along the last axis of an array. The data in arrays can be rotated into new positions with the dyadic function rotate. This treatment of polynomial multiplication is appealing because it solves a commonly occurring problem, uses an intermediate higher dimensional array, and achieves a concise solution. Laminate is an APL function that takes two arrays with the same shape and attaches them along a new axis of length 2.
