详解Lua中的表的概念及其相关操作方法

--sample table initialization
mytable = {}

 

--simple table value assignment
mytable[1]= "Lua"

--removing reference
mytable = nil
-- lua garbage collection will take care of releasing memory

-- Simple empty table
mytable = {}
print("Type of mytable is ",type(mytable))

 

mytable[1]= "Lua"
mytable["wow"] = "Tutorial"
print("mytable Element at index 1 is ", mytable[1])
print("mytable Element at index wow is ", mytable["wow"])

-- alternatetable and mytable refers to same table
alternatetable = mytable

print("alternatetable Element at index 1 is ", alternatetable[1])
print("mytable Element at index wow is ", alternatetable["wow"])

alternatetable["wow"] = "I changed it"

print("mytable Element at index wow is ", mytable["wow"])

-- only variable released and and not table
alternatetable = nil
print("alternatetable is ", alternatetable)

-- mytable is still accessible
print("mytable Element at index wow is ", mytable["wow"])

mytable = nil
print("mytable is ", mytable)

Type of mytable is  table
mytable Element at index 1 is  Lua
mytable Element at index wow is  Tutorial
alternatetable Element at index 1 is  Lua
mytable Element at index wow is  Tutorial
mytable Element at index wow is  I changed it
alternatetable is  nil
mytable Element at index wow is  I changed it
mytable is  nil

fruits = {"banana","orange","apple"}
-- returns concatenated string of table
print("Concatenated string ",table.concat(fruits))

 

--concatenate with a character
print("Concatenated string ",table.concat(fruits,", "))

--concatenate fruits based on index
print("Concatenated string ",table.concat(fruits,", ", 2,3))

Concatenated string  bananaorangeapple
Concatenated string  banana, orange, apple
Concatenated string  orange, apple

fruits = {"banana","orange","apple"}

 

-- insert a fruit at the end
table.insert(fruits,"mango")
print("Fruit at index 4 is ",fruits[4])

--insert fruit at index 2
table.insert(fruits,2,"grapes")
print("Fruit at index 2 is ",fruits[2])

print("The maximum elements in table is",table.maxn(fruits))

print("The last element is",fruits[5])
table.remove(fruits)
print("The previous last element is",fruits[5])

Fruit at index 4 is  mango
Fruit at index 2 is  grapes
The maximum elements in table is 5
The last element is mango
The previous last element is nil

fruits = {"banana","orange","apple","grapes"}
for k,v in ipairs(fruits) do
print(k,v)
end
table.sort(fruits)
print("sorted table")
for k,v in ipairs(fruits) do
print(k,v)
end

1 banana
2 orange
3 apple
4 grapes
sorted table
1 apple
2 banana
3 grapes
4 orange