一、copy

（1）用copy修饰的 或者赋值的 变量肯定是不可变的。

    NSMutableArray *muteArray = [NSMutableArray arrayWithCapacity:10];
    [muteArray addObject:@"1"];
    NSArray *array  = [muteArray copy];
    NSLog(@"\n mArr1 = %@ mArr1P = %p mArr1 class = %@ \n\n mArr2 = %@ mArr2P = %p mArr2 class = %@", muteArray, muteArray, [muteArray class], array, array, [array class]);

image.png

（2）用copy赋值，要看源对象是否是可变的，来决定只拷贝指针，还是也拷贝对象到另一块内存空间

    NSString *str1 = @"str1";
    NSString *str2 = [str1 copy];
    NSLog(@"\nstr1 = %@ str1P = %p \n str2 = %@ str2P = %p", str1, str1, str2, str2);
    str1 = @"asdf";
     NSLog(@"\nstr1 = %@ str1P = %p \n str2 = %@ str2P = %p", str1, str1, str2, str2);

image.png

二、mutableCopy

（1）对象之间mutableCopy赋值，肯定会拷贝整个对象内存到另一块内存中

    NSMutableString *mStr1 = [@"123" mutableCopy];
    NSMutableString *mStr2 = [mStr1 mutableCopy];
    NSLog(@"\n mStr1 = %@ mStr1P = %p \n mStr2 = %@ mStr2P = %p", mStr1, mStr1, mStr2, mStr2);
/*输出结果，可以得出下图结论
       mStr1 = 123 mStr1P = 0x6000004460c0
       mStr2 = 123 mStr2P = 0x600000446420
     */