1. NSArray 기본 개념

2. OC 그룹을 만드는 방법

    NSArray *arr = [NSArray arrayWithObjects:@"lnj", @"lmj", @"jjj"];
    NSArray *arr = @[@"lnj", @"lmj", @"jjj"];
    //  
    NSLog(@"%@", [arr objectAtIndex:0]);
    NSLog(@"%@", arr[0]);

3. OC 수조 방법

4. NSArray 스트리밍

for (int i = 0; i < arr.count; ++i) {
        NSLog(@"arr  = %@,count = %i", arr[i],(int )i);
    }

for (NSString *obj in arr) {
        NSLog(@"obj = %@", obj);
    }

  [arr enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        NSLog(@"obj = %@, idx = %lu", obj,idx);
    }];

5. NSArray의 모든 개체에 대한 메서드 메시지

[arr makeObjectsPerformSelector:@selector(say)];
[arr makeObjectsPerformSelector:@selector(sayWithName:) withObject:@"lnj"];

배열 정렬

    NSArray *arr = @[@(1),@(54),@(2),@(34),@(66),@(21),@(660),@(3),@(23),@(566)];
    NSArray *newArr = [arr sortedArrayUsingSelector:@selector(compare:)];
    NSLog(@"%@", newArr);

    NSArray *arr = @[@(1),@(54),@(2),@(34),@(66),@(21),@(660),@(3),@(23),@(566)];
//    NSArray *newArr = [arr sortedArrayUsingSelector:@selector(compare:)];
    NSArray *newArr =[arr sortedArrayWithOptions:NSSortStable usingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
       return obj1 < obj2;
    }];
    NSLog(@"%@", newArr);

7. NSArray 및 NSString 전환

    NSArray *arr = @[@"lm1",@"lm2",@"lm3",@"lm4", ];
    NSString *str = [arr componentsJoinedByString:@"-love-"];
    NSLog(@"%@", str);
// ： lm1-love-lm2-love-lm3-love-lm4

    NSArray *arr = @[@"lm1",@"lm2",@"lm3",@"lm4", ];
    NSString *str = [arr componentsJoinedByString:@"-love-"];
    NSLog(@"%@", str);
    NSArray * newArr = [str componentsSeparatedByString:@"love"];
    NSLog(@"newArr:%@", newArr);

8. NSArray 파일 읽기와 쓰기

NSMutableArray

1. NSMutable Array 소개

2. NSMutableArray의 기본 사용 방법

NSMutableArray *arrM = [NSMutableArray array];

[arrM addObject:@"lnj"];
[arrM addObjectsFromArray:@[@"lmj", @"jjj"]];

[arrM insertObject:@"xcq" atIndex:1];

[arrM removeObjectAtIndex:0];
     NSLog(@"%@", arrM);

    [arrM removeLastObject];
    NSLog(@"%@", arrM);

    [arrM removeObject:@"A"];
     NSLog(@"%@", arrM);

[arrM replaceObjectAtIndex:1 withObject:@"M"];
    NSLog(@"%@", arrM);

[arrM objectAtIndex:3];
    NSLog(@"%@",arrM[3]);