ios - 比较两个 NSArray 并检测变化的最佳方法是什么

Question

我的要求是确定地址簿中的更改(哪些联系人和哪些字段自上次打开应用程序以来发生了更改。

现在我有两个 NSArrays 作为 arrSavedContacts(包含以前的地址簿联系人)和 arrContacts(当前地址簿联系人)。这就是两个数组的样子

arrSavedContacts

{
    firstName = Gayan;
    id = 224;
    lastName = Udaha;
    phones =         (
                    {
            label = Mobile;
            value = "123456789";
        }
    );
},
    {
    firstName = Chandrananda;
    id = 225;
    lastName = "";
    phones =         (
                    {
            label = Mobile;
            value = "234567891";
        }
    );
},
    {
    firstName = Joe;
    id = 228;
    lastName = B8;
    phones =         (
                    {
            label = Mobile;
            value = "345678912";
        }
    );
},

arr联系人

{
    firstName = FirstName Changed;
    id = 224;
    lastName = Udaha;
    phones =         (
                    {
            label = Mobile;
            value = "123456789";
        }
    );
},
    {
    firstName = Chandrananda;
    id = 225;
    lastName = "";
    phones =         (
                    {
            label = Mobile;
            value = "345678912";
        }
    );
},

对于上面的两个数组，我们可以注意到两个变化，第 3 项被删除，第 1 项中的 firstName 被更改。

由于地址簿中可以有数千个项目，我的问题是，比较这两个数组并检测更改的项目(删除、添加、内部字段的更改)的最佳和最佳方法是什么？

非常感谢代码示例

Answer 1

这是检查更改、添加和删除的代码。请检查，如果您不明白，请评论...

NSMutableArray *oldArr =[NSMutableArray arrayWithArray:@[@{
                                                             @"firstName" : @"Gayan",
                                                             @"id" : @224,
                                                             @"lastName" : @"Udaha",
                                                             @"phones": @[
                                                                     @{
                                                                         @"label" : @"Mobile",
                                                                         @"value" : @"123456789"
                                                                      }
                                                                     ]
                                                             },
                                                         @{
                                                             @"firstName" : @"Chandrananda",
                                                             @"id" : @225,
                                                             @"lastName" : @"",
                                                             @"phones": @[
                                                                     @{
                                                                         @"label" : @"Mobile",
                                                                         @"value" : @"234567891"
                                                                         }
                                                                     ]
                                                             },
                                                         @{
                                                             @"firstName" : @"Joe",
                                                             @"id" : @226,
                                                             @"lastName" : @"",
                                                             @"phones": @[
                                                                     @{
                                                                         @"label" : @"Mobile",
                                                                         @"value" : @"345678912"
                                                                         }
                                                                     ]
                                                             },
]];

NSMutableArray *newArr =[NSMutableArray arrayWithArray:@[@{
                                                             @"firstName" : @"Gayan",
                                                             @"id" : @224,
                                                             @"lastName" : @"Udaha",
                                                             @"phones": @[
                                                                     @{
                                                                         @"label" : @"Mobile",
                                                                         @"value" : @"123456789"
                                                                         }
                                                                     ]
                                                             },
                                                         @{
                                                             @"firstName" : @"Chandrananda",
                                                             @"id" : @225,
                                                             @"lastName" : @"",
                                                             @"phones": @[
                                                                     @{
                                                                         @"label" : @"Mobile",
                                                                         @"value" : @"11111111"
                                                                         }
                                                                     ]
                                                             },
                                                         @{
                                                             @"firstName" : @"Luan",
                                                             @"id" : @229,
                                                             @"lastName" : @"",
                                                             @"phones": @[
                                                                     @{
                                                                         @"label" : @"Mobile",
                                                                         @"value" : @"55555555"
                                                                         }
                                                                     ]
                                                             },
                                                         ]];


NSMutableSet *oldSet = [NSMutableSet setWithArray:oldArr];
NSMutableSet *newSet = [NSMutableSet setWithArray:newArr];

//1: Get filter all changed, add, delete items

[oldSet minusSet:newSet];
[newSet minusSet:oldSet];

NSArray *remainOldArr = [NSArray arrayWithArray:[oldSet allObjects]];
NSArray *remainNewArr = [NSArray arrayWithArray:[newSet allObjects]];

if (remainNewArr.count == 0 && remainOldArr.count == 0) {
    // there is no changes.
    return ;
}

//2: detect which items changed,add,delete

NSMutableArray *arrayChangedItems = nil;
NSMutableArray *arrayDeleteItems = nil;
NSMutableArray *arrayAddItems =nil;

NSPredicate *pre1 = [NSPredicate predicateWithFormat:@"self.id IN %@",[remainOldArr valueForKeyPath:@"id"]];
NSPredicate *pre2 = [NSPredicate predicateWithFormat:@"NOT self.id IN %@",[remainOldArr valueForKeyPath:@"id"]];
NSPredicate *pre3 = [NSPredicate predicateWithFormat:@"NOT self.id IN %@",[remainNewArr valueForKeyPath:@"id"]];

arrayChangedItems = [NSMutableArray arrayWithArray:[remainNewArr filteredArrayUsingPredicate:pre1]];
arrayAddItems = [NSMutableArray arrayWithArray:[remainNewArr filteredArrayUsingPredicate:pre2]];
arrayDeleteItems = [NSMutableArray arrayWithArray:[remainOldArr filteredArrayUsingPredicate:pre3]];