Objective-C中NSString和NSMutableString的基本用法

int main(int argc, const char * argv[])

{



    @autoreleasepool {

        

        //----------------NSString-----------------------------

        NSString *str1 = @"这是一个字符串常量";

        NSLog(@"str1 = %@",str1);

        //创建一个空字符串

        NSString *str2 = [[NSString alloc]init];

        NSString *str3 = [NSString string];

        NSLog(@"str2 = %@",str2);

        NSLog(@"str3 = %@",str3);

        //快速创建一个字符串

        NSString *str4 = [[NSString alloc]initWithString:str1];

        NSString *str5 = [NSString stringWithString:str1];

        NSLog(@"str4 = %@",str4);

        NSLog(@"str5 = %@",str5);

        //创建一个格式化字符串

        NSString *str6 = [[NSString alloc]initWithFormat:@"%d",10];

        NSString *str7 = [NSString stringWithFormat:@"%.2f",10.8099887];

        NSLog(@"str6 = %@",str6);

        NSLog(@"str7 = %@",str7);

        

        //比较两个字符串内容是否相等

        if ([str6 isEqualToString:str7]) {

            NSLog(@"str6 is EqualToString str7");

        }else{

            NSLog(@"str6 is not EqualToString str7");

        }

        

        //转换为基本数据类型

        NSString *str8 = @"3";

        float f1 = [str8 floatValue];

        NSLog(@"str8 = %.2f",f1);

        

        //字符串拆分为数组

        NSString *str9 = @"命 运 就 算 颠 沛 流 离";

        NSArray *array = [str9 componentsSeparatedByString:@" "];

        NSLog(@"array = %@",array);

        NSLog(@"array[0] = %@",array[0]);

        

        //截取字符串

        NSString *str10 = @"123456789";

        NSString *subStr1 = [str10 substringToIndex:4];

        NSString *subStr2 = [str10 substringFromIndex:6];

        NSLog(@"subStr1 = %@",subStr1);

        NSLog(@"subStr2 = %@",subStr2);

        

        NSRange range = {4,2};

        NSString *subStr3 = [str10 substringWithRange:range];

        NSLog(@"subStr3 = %@",subStr3);

        

        //拼接字符串

        NSString *str11 = @"123";

        NSString *str12 = @"456";

        NSString *appStr1 = [[NSString alloc]initWithFormat:@"%@%@",str11,str12];

        NSString *appStr2 = [str11 stringByAppendingFormat:@"%@",str12];

        NSString *appStr3 = [str11 stringByAppendingString:str12];

        NSLog(@"appStr1 = %@",appStr1);

        NSLog(@"appStr2 = %@",appStr2);

        NSLog(@"appStr3 = %@",appStr3);

        

        //查找字符串

        NSString *str13 = @"qweradsfzxcvqazxsw";

        NSRange range1 = [str13 rangeOfString:@"dsfzx"];

        NSLog(@"%@",NSStringFromRange(range1));

        NSLog(@"%d",range1.location);

        if (range1.location != NSNotFound) {

            NSLog(@"str found");

        }else{

            NSLog(@"str not found");

        }

        

        /*------------NSMutableString 可变字符串-----------------*/

        //插入

        NSMutableString *mStr1 = [[NSMutableString alloc] initWithFormat:@"abcd"];

        [mStr1 insertString:@"defg" atIndex:4];    //注意：此处为在源字符串上修改，并未生成新的字符串

        NSLog(@"mStr1 = %@",mStr1);

        

        //替换

        [mStr1 replaceCharactersInRange:NSMakeRange(4, 4) withString:@"1234"];

        NSLog(@"%@",mStr1);

        

        //删除

        [mStr1 deleteCharactersInRange:NSMakeRange(4, 4)];

        NSLog(@"%@",mStr1);

    }

    return 0;

}