Lua 学习之------函数功能

example：

                function Wow()

                           print(" ")

                           print("Wow , that was awesome")

                           print(" ")

                 end

单一参数： function SetName(myString)

                            print(" ")

                            print("Your name is :", myString)

                            print(" ")

                    end

多个参数： function SetName(myName, myAge)

                            print(" ")

                            print("Your name is :", myString)

                            print("Your name is :", myString)

                            print(" ")

                    end

返回 值：

              function TimesTwo(myValue)

                           myValue = myValue * 2

                           return myValue

              end

可以返回多个结果：

               function ThreeDice()

                        d1 = math.random(0,1)

                        d2 = math.random(0,1)

                        d3 = math.random(0,1)

                        myValue = d1 + d2 + d3

                        return d1,d2,d3,myValue

                end

类型转换：

把字符转换成数字：

                 myString = "1234"

                 myNumber = tonumber(myString)

                 print(myNumber + 2)

tostring() 函数把数字转换成字符：

                  myNumber = 1234

                  myString = tostring(myNumber)

                  print(myString)

string.len(myString) 获取字符串的长度后函数

string.sub(myString ,start,end) 返回知道字符串的子串 ，start参数指定子串的开始位置，end 指定子串的结束位置

string.format() 格式化输出指定的字符串， 同时可以用来连接字符串

                  string1 = "hello"

                  string2 = "world"

                  for indx = 1, 3 do

                        string1 = string.format("%s%s", string1, string2)

                   end

                   print(string1)

string.find(sourceString , findString)  在sourceString 中查找第一个符合findString字符的位置， 如果找到改目标字符则返回它的开始和结束位置，如果没有找到则返回nil