lua中的pairs和ipairs差别

pairs

Returns three values: the next function, the table t, and nil,
so that the construction

     for k,v in pairs(t) do body end

will iterate over all key–value pairs of table t.

See function next for the caveats of modifying the table during its traversal.

ipairs

Returns three values: an iterator function, the table t, and 0, so that the construction

     for i,v in ipairs(t) do body end

will iterate over the pairs (1,t[1]), (2,t[2]), ···, up to the first integer key absent from the table.

实例一

local tabFiles = {"a","b","c",[7]="d",[8]="e"}

for k,v in ipairs(tabFiles) do

        print(k,v)

end



for k,v in pairs(tabFiles) do

        print(k,v)

end

输出结果为：

1       a

2       b

3       c

1       a

2       b

3       c

7       d

8       e

实例二

local tabFiles = {"a","b","c",[3]="d",[4]="e"}

for k,v in ipairs(tabFiles) do

        print(k,v)

end



for k,v in pairs(tabFiles) do

        print(k,v)

end

结果为：

1       a

2       b

3       c

4       e

1       a

2       b

3       c

4       e

实例三

local tabFiles = {"a","b","c",[m]="d",[4]="e"}

for k,v in ipairs(tabFiles) do

        print(k,v)

end



for k,v in pairs(tabFiles) do

        print(k,v)

end

输出结果为：

1       a

2       b

3       c

4       e

1       a

2       b

3       c

m       d

4       e