1.字符串相加连接的三种方法：

NSString* string; // 结果字符串 NSString* string1, string2; //已存在的字符串，需要将string1和string2连接起来   //方法1. string = [NSString initWithFormat:@"%@,%@", string1, string2 ]; //方法2. string = [string1 stringByAppendingString:string2]; //方法3 . string = [string stringByAppendingFormat:@"%@,%@",string1, string2];

2，字符转int

int intString = [newString intValue];

3，int转字符

NSString *stringInt = [NSString stringWithFormat:@"%d",intString];

4，字符转float

 float floatString = [newString floatValue];

5，float转字符

NSString *stringFloat = [NSString stringWithFormat:@"%f",intString];