Lesson 26 of 55
9 mins readPython Tables as 1-Based Arrays & Length (#)
In Plain English
When using tables as arrays, Lua convention uses 1-based indexing: `list[1]` is the first element. The length operator `#list` returns the number of elements in a sequence.
Deep Dive: How It Works
1-Based Indexing: Standard in Lua since its engineering roots at Petrobras/PUC-Rio.
Length Operator (#): Returns index `n` such that `t[n] ~= nil` and `t[n + 1] == nil`.
Appending Elements: `list[#list + 1] = new_value` is standard Lua idiom for appending.
Core Rules to Remember
1-Based Convention: First item is at index 1, last is at `#table`.
Append Idiom: `t[#t + 1] = val` appends to the end of a sequence.
Live Interactive Example
Hit Run Code to see it liveArray Indexing and Appending
Python 3.12
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Output Console
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How it works: languages[1] accessed the first item and #languages[#languages + 1] appended Rust.
Your Turn: Micro Challenge
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Micro Exercise
Append and Query Sequence
- Declare `local list = { 10, 20 }`.
- Append 30: `list[#list + 1] = 30`.
- Print `"Count: " .. #list .. " Last: " .. list[#list]`.
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Sandbox Output
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