lua（二）循环

1. while    

[xuhaixing@localhost lua]$ cat while.lua 
local a = 1;
while(a<10) do
  print("a="..a)
  a=a+1
end
[xuhaixing@localhost lua]$ lua while.lua 
a=1
a=2
a=3
a=4
a=5
a=6
a=7
a=8
a=9

2. for

   for后面有三个参数，从exp1 变化到exp2，步长为exp3，exp3为可选的，不指定，默认为1

[xuhaixing@localhost lua]$ cat for0.lua 
for i = 10,1,-2 do
  print(i)
end
[xuhaixing@localhost lua]$ lua for0.lua 
10
8
6
4
2

  for循环里面是方法，只在开始初始化一次   

[xuhaixing@localhost lua]$ cat for1.lua 
function fun(x)
  print("function")
  return x*2
end

for i = 1,fun(5) do
  print(i)
end
[xuhaixing@localhost lua]$ lua for1.lua 
function
1
2
3
4
5
6
7
8
9
10

 for循环table类型   

[xuhaixing@localhost lua]$ cat for2.lua 
local a = {"aa","bb","cc"}
for i,v in ipairs(a) do
  print(i,v)
end
[xuhaixing@localhost lua]$ lua for2.lua 
1  aa
2  bb
3  cc

3. repeat...until      

[xuhaixing@localhost lua]$ cat repeat.lua 
local a = 1
repeat
  print(a)
  a=a+1
until(a>10)
[xuhaixing@localhost lua]$ lua repeat.lua 
1
2
3
4
5
6
7
8
9
10

4.break跳出循环   

[xuhaixing@localhost lua]$ cat break.lua 
local a = 1;
while a<100 do
  if(a%5==0) then
    print(a)
    break
  end
  a=a+1
end 
[xuhaixing@localhost lua]$ lua break.lua 
5

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