The difference between pairs and ipairs

stay lua in ipairs and pairs Can be used to traverse the set , But there's a difference between the two ;

Same as ： Can traverse the set （ surface 、 Array ）, Both of them are output in order without key Value ;

different ： For having key Set ：
ipairs From the first number key Start , Output all... In turn key+1 Key value of , Encountering an alphabetic subscript does not end the traversal , Just don't output , If you encounter nil The exit ;
pairs Unordered output letter type key Or number type key Key value of , encounter nil No output , But it won't stop traversing ;

Example 1：

table = {
     [1] = "test3", [2] = "val1" , [5] = "val2", [4] = "val4" }
print("-----------ipairs----------------")
for k,v in ipairs(table) do
    print(k,v)
end
print("-----------pairs----------------")
for k,v in pairs(table) do
    print(k,v)
end

Output

-----------ipairs----------------
1	test3
2	val1
-----------pairs----------------
4	val4
1	test3
2	val1
5	val2

Conclusion ：
1、ipairs According to key Sequential output data of , Stop outputting when encountering discontinuous data ;
2、pairs All data will be output out of order ;

Example 2：

table = {
     [3] = "test3", ["test"] = "val1", "val3" , [4] = "val2", "val4" }
print("-----------ipairs----------------")
for k,v in ipairs(table) do
    print(k,v)
end
print("-----------pairs----------------")
for k,v in pairs(table) do
    print(k,v)
end

Output

-----------ipairs----------------
1	val3
2	val4
3	test3
4	val2
-----------pairs----------------
1	val3
2	val4
4	val2
test	val1
3	test3

Conclusion ：
1、pairs and ipairs All priority output without key Of value;
2、pairs All data will be output , No key The values of are output in sequence , belt key The value of is output out of order ;
3、ipairs Will skip the string key, Output digital type in sequence key Value ;

Example 3

table = {
     [6] = "test3", ["test"] = "val1", "val3" , [11] = "val2", nil, "val4" }
print("-----------ipairs----------------")
for k,v in ipairs(table) do
    print(k,v)
end
print("-----------pairs----------------")
for k,v in pairs(table) do
    print(k,v)
end

Output

-----------ipairs----------------
1	val3
-----------pairs----------------
1	val3
3	val4
11	val2
6	test3
test	val1

Conclusion ：
1、ipairs encounter nil Will stop output ;
2、pairs encounter nil Output will not stop ;