由於此系列文本主旨在 NumPy 之陣列運算，雖特介紹 APL 語言，恐不宜喧賓奪主，因此有關該語言參考文件還請讀者自己研習哩︰

Documentation Centre (17.0)

All our documentation is available free of charge in electronic form. In addition, Bernard Legrand’s Mastering Dyalog APL is available from Amazon.

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Unless otherwise mentioned, the documentation on this page is for Dyalog version 17.0 and components shipped with that release. For other versions, see the links at the end of the page.

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所以留心專注的是初始『設計』

Design

Unlike traditionally structured programming languages, APL code is typically structured as chains of monadic or dyadic functions, and operators[50] acting on arrays.[51] APL has many nonstandard primitives (functions and operators) that are indicated by a single symbol or a combination of a few symbols. All primitives are defined to have the same precedence, and always associate to the right. Thus, APL is read or best understood from right-to-left.

Early APL implementations (circa 1970 or so) had no programming loop-flow control structures, such as do or while loops, and if-then-else constructs. Instead, they used array operations, and use of structured programming constructs was often not necessary, since an operation could be performed on a full array in one statement. 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. More recent implementations of APL generally include comprehensive control structures, so that data structure and program control flow can be clearly and cleanly separated.

之『思維方法』也。

故假 APL 質數範例，擬借 NumPy 對應行之︰