Lua iterator

Reading guide iterator （iterator） It's a kind of object , It can be used to traverse some or all of the elements in the standard template library , Each iterator object represents a certain address in the container . stay Lua Iterators in are structures that support pointer types , It can traverse every element of the collection .Lua Iterators in can be divided into generic types for iterator 、 Stateless iterators and multistate iterators .
Generic for iterator explain
Generic for Save the iteration function inside yourself , In fact, it holds three values ： Iterative function 、 State constant 、 Control variables . Generic for The iterator provides the of the collection key/value Yes .
grammar

  
 
 

   
  
  
for k, v in pairs(t) doprint(k, v)
   
  
  
end
  
 
 

Case study Generic for iterator
Generic for Iterator traverses the array

  
 
 

   
  
  
#!/usr/bin/luaprint("haicoder()\n")
   
  
  
array = {"Hello", "HaiCoder", "Lua"}
   
  
  
for k, v in ipairs(array)
   
  
  
do
   
  
  
print(string.format("Key = %d, Value = %s", k, v))
   
  
  
end
  
 
 

The program runs , Console output , Here's the picture ：

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We can see , We use generics for The iterator traversed the array elements .
Lua Iterator summary iterator （iterator） It's a kind of object , It can be used to traverse some or all of the elements in the standard template library , Each iterator object represents a certain address in the container .
stay Lua Iterators in are structures that support pointer types , It can traverse every element of the collection .Lua Iterators in can be divided into generic types for iterator 、 Stateless iterators and multistate iterators .
Generic for Save the iteration function inside yourself , In fact, it holds three values ： Iterative function 、 State constant 、 Control variables . Generic for The iterator provides the of the collection key/value Yes .

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