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Unexpected nil value when iterating over Lua table using pairs() with nested tables

👀 Views: 2202 đŸ’Ŧ Answers: 1 📅 Created: 2025-05-31
lua tables iteration Lua

I'm updating my dependencies and I'm sure I'm missing something obvious here, but I'm migrating some code and I've spent hours debugging this and I'm working with an scenario with iterating over a Lua table that contains nested tables. I have a structure like this: ```lua local data = { user1 = {name = "Alice", age = 30}, user2 = {name = "Bob", age = 25}, user3 = nil, user4 = {name = "Charlie", age = 35} } ``` When I try to iterate over this table using `pairs()`, I'm getting a "nil value" behavior when it encounters `user3`. Here's the code I'm using: ```lua for key, value in pairs(data) do print(key, value.name, value.age) end ``` Since `user3` is `nil`, I thought I could handle it using an `if` check, but it seems that the `value` itself is `nil` before I can even perform that check. The behavior I get is: ``` nil value ``` How can I safely iterate over my table without working with an behavior? I've also tried using `next()` to iterate: ```lua local k, v = next(data) while k do print(k, v.name, v.age) k, v = next(data, k) end ``` However, the same behavior occurs. I'm using Lua 5.4. What is the best practice here to avoid these nil references while iterating? Should I be using a different approach or is there a way to safely check if a table entry is `nil` during iteration? For context: I'm using Lua on Linux. Thanks in advance! Has anyone else encountered this? Thanks for your help in advance!