学步园

/--------操作字符串--NSString(静态字符串)---------------------
    NSString
*Beijing= @"北京欢迎您";        //字符串的声明
    NSString
*log=@"北京欢迎您a"; //[NSString stringWithFormat:@"I am '%@'",Beijing];     //字符串格式化
    NSString
*zhui = [Beijing stringByAppendingString:@"哈哈哈"];        //字符串追加
    bool
b=[Beijing isEqualToString:log];                               //字符串比较
    NSString
*hh = @"http://www.sina.com.cn";
    if([hh
hasPrefix:@"http"]){                                          //查找以http开头的字符串
        NSLog(@"含有http");
    }else{
        NSLog(@"没有http");
    }
    NSString
*ss = @"123";
    int
a = [ss intValue]+13;                                   //字符串转int型
    double
dd = [ss doubleValue]+33.3;                          //字符串转double型
    NSLog(@"%g",dd);
//字符串转数组 
    NSString
*zifuchuan =@"one,two,three,four";
    NSLog(@"string:%@",zifuchuan);
    NSArray
*array = [zifuchuan componentsSeparatedByString:@","];
//    NSLog(@"array:%@",array);                             //输出整个数组中所有元素 
    NSString
*value = [array objectAtIndex:0];