NSArray、NSMutableArray相关

移除相同的

 NSMutableArray *arr001 = [_selectedArr mutableCopy];
    for(int i=0;i<_selectedArr.count;i++){
        ContactPersonInfo *dic  = _selectedArr[i];
        
        NSMutableArray *arr002 = [NSMutableArray array];
        for(int j=0;j<i;j++){
            [arr002 addObject:_selectedArr[j]];
        }
        
        if (arr002.count>0) {
            for(ContactPersonInfo *dic0 in arr002){
                if ([dic0.user_id integerValue] == [dic.user_id integerValue] ) {
                    [arr001 removeObject:dic];
                }
            }
        }
    }

排序

NSArray *result = [arr001 sortedArrayUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
                 NSLog(@"%@~%@",obj1,obj2); //3~4 2~1 3~1 3~2
             NSDictionary *dic1 = obj1;
             NSDictionary *dic2 = obj2;
             NSNumber *num1 = dic1[@"num"] ;
             NSNumber *num2 = dic2[@"num"] ;
                 return [num1 compare:num2]; //升序
             }];

1.求和、最值

float sum = [[arr valueForKeyPath:@"@sum.floatValue"] floatValue];//求和
float avg = [[arr valueForKeyPath:@"@avg.floatValue"] floatValue];//求平均值
float max = [[arr valueForKeyPath:@"@max.floatValue"] floatValue];//求最大值
float min = [[arr valueForKeyPath:@"@min.floatValue"] floatValue];//求最小值

NSArray

1.是否包含某个元素

[array containsObject: str]

NSMutableArray

1.替换对象

NSMutableArray *newArray = [_regionDetailDataArr mutableCopy];
[newArray replaceObjectAtIndex:_selectedIndex withObject:newDic];
_regionDetailDataArr = newArray;

数组与 json 互转

json->nsarray

-(id)jsonToObject:(NSString *)json{
    //string转data
    NSData * jsonData = [json dataUsingEncoding:NSUTF8StringEncoding];
    //json解析
    id obj = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];
    return obj;
}

nsarray -> json

 NSError *error = nil;

 NSData *jsonData = [NSJSONSerialization dataWithJSONObject:arr
                                                                               options:kNilOptions
                                                                              error:&error];
NSString *jsonString = [[NSString alloc] initWithData:jsonData
                                                                         encoding:NSUTF8StringEncoding];

排序

1. NSArray *arr = @[@"fdaf", @"fdafd", @"1", @"fadfdafdsaf"];

2. NSArray *a0 = [arr sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {

3. NSUInteger len0 = [(NSString *)obj1 length];

4. NSUInteger len1 = [(NSString *)obj2 length];

5. return len0 > len1 ? NSOrderedAscending : NSOrderedDescending;

6. }];

7. NSLog(@"origin:%@\nsorted:%@", arr, a0);

1. NSArray *newArray = [allUserName sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {

2. NSUInteger len0 = [(NSString*)obj1 length];

3. NSUInteger len1 = [(NSString*)obj2 length];

4. return len0>len1 ? NSOrderedDescending : NSOrderedAscending;

5. }];