This first edition was written for Lua 5.0. While still largely relevant for later versions, there are some differences.
The fourth edition targets Lua 5.3 and is available at Amazon and other bookstores.
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19 – The Table Library

The table library comprises auxiliary functions to manipulate tables as arrays. One of its main roles is to give a reasonable meaning for the size of an array in Lua. It also provides functions to insert and remove elements from lists and to sort the elements of an array.