Function: Print Task Summary
Part of the Introduction To Luau section of Coddy's Lua journey. Lesson 51 of 80.
Challenge
EasyAdd a function that prints how far along the list is.
- Delete the lines under
-- Try it. - Write
local function printSummary(list: {Task}): ()that counts the done tasks and prints`{doneCount}/{#list} tasks done`. - Under
-- Try it, callprintSummary(tasks), thencompleteTask(tasks, 2), thenprintSummary(tasks)again.
Press Run Code: the output shows 1/3 tasks done, then 2/3 tasks done.
Try it yourself
-- The shape every task in the manager follows
type Task = {
id: number,
title: string,
done: boolean,
}
local tasks: {Task} = {
{id = 1, title = "Learn Luau types", done = false},
{id = 2, title = "Build a task manager", done = false},
{id = 3, title = "Write tests", done = true},
}
-- Build a task with the next free id and add it to the list
local function addTask(list: {Task}, title: string): Task
local newTask: Task = {id = #list + 1, title = title, done = false}
table.insert(list, newTask)
return newTask
end
-- Mark the task with this id as done; say whether one was found
local function completeTask(list: {Task}, id: number): boolean
for _, t in ipairs(list) do
if t.id == id then
t.done = true
return true
end
end
return false
end
-- A new list of the tasks whose done flag matches
local function filterTasks(list: {Task}, done: boolean): {Task}
local result: {Task} = {}
for _, t in ipairs(list) do
if t.done == done then
table.insert(result, t)
end
end
return result
end
-- Try it
local pending = filterTasks(tasks, false)
print(#pending)
print(pending[2].title)
All lessons in Introduction To Luau
1Getting Started with Luau
What Is Luau?Why Use Luau?Your First Luau CodeType Checking & Error ModesRecap: Introduction to Luau4Working with Functions
Typing Params & Return ValuesTyping Anonymous FunctionsFunctions Returning NothingOptional ParametersDefault Parameter ValuesDefaults for BooleansVariadic FunctionsDefining Function TypesRecap: Typed Functions7Project: Typed Task Manager
Project: The Task ShapeFunction to Add a Task2Core Types
Number, String and BooleanThe 'any' Type: Escape HatchThe 'unknown' TypeNil & Optional TypesType Inference in ActionExplicit Type AnnotationsRecap: Core Types Practice5Aliases, Unions, Intersections
Type Aliases for PrimitivesUnion TypesWorking with Union TypesLiteral TypesIntersection TypesCombining Type AliasesRecap: Advanced Type Combos3Typed Tables: Arrays & Maps
Typed ArraysAdding and Reading ElementsWhat is a Map Type?Declaring and Accessing MapsIterating TablesMixed-Shape TablesReading a GridBuilding a Gridtable.unpackRecap: Arrays and MapsPractice on your own: Online Luau compiler