iOS学习路之Objective-C（四）—— NSArray

 1     //创建数组的时候数组成员放在中括号中，NSLog打印时，数组是被放在小括号中
 2     NSArray *array = @[@"bei", @"jing", @"huan", @"ying", @"nin"];
 3
 4 #if 0
 5 #pragma mark 对象方法创建数组
 6     NSArray *array1 = [[NSArray alloc] initWithArray:array1];
 7     NSArray *array2 = [[NSArray alloc] initWithObjects:@"bei", @"jing", @"huan", @"ying", @"nin", nil];
 8 #endif
 9
10 #pragma mark 类方法创建数组
11     NSArray *array1 = [NSArray arrayWithArray:array];
12     NSArray *array2 = [NSArray arrayWithObjects:@"bei", @"jing", @"huan", @"ying", @"nin", nil];

1     //实例化一个数组对象
2     NSArray *array = @[@"bei", @"jing", @"huan", @"ying", @"nin"];
3     //@property (readonly) NSUInteger count;
4     //作用：获取数组中的成员个数
5     NSLog(@"%lu",[array count]);

1     //实例化一个数组对象
2     NSArray *array = @[@"bei", @"jing", @"huan", @"ying", @"nin"];
3     //- (id)objectAtIndex:(NSUInteger)index;
4     //作用：根据下标获取数组中对应的元素
5     NSLog(@"%@", [array objectAtIndex:0]);

1     NSArray *array = @[@"bei", @"jing", @"huan", @"ying", @"nin"];
2     //- (NSUInteger)indexOfObject:(id)anObject;
3     //作用：根据元素的值找第一个对应的下标
4     NSLog(@"%lu", [array indexOfObject:@"huan"]);

 1     NSString *string1 = @"chen$chao$ni$hao$ma";
 2     //- (NSArray *)componentsSeparatedByString:(NSString *)separator;
 3     //作用：将字符串按照某个字符串进行分割，分割后的字符串保存在一个数组中作为数组的元素
 4     NSArray *arrayFromString1 = [string1 componentsSeparatedByString:@"$"];
 5
 6     //- (NSString *)componentsJoinedByString:(NSString *)separator;
 7     //作用：将数组中的元素按照某个字符串拼接成一个字符串
 8     NSString *stringFromArray1 = [arrayFromString1 componentsJoinedByString:@" "];
 9     NSLog(@"%@", stringFromArray1);
10
11     //- (NSArray *)componentsSeparatedByCharactersInSet:(NSCharacterSet *)separator NS_AVAILABLE(10_5, 2_0);
12     //作用：按照字符集进行切割
13     NSString *string2 = @"chen$chao#[email protected]&ma";
14     NSArray *arrayFromString2 = [string2 componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"$#@&"]];
15     NSString *stringFromArray2 = [arrayFromString2 componentsJoinedByString:@" "];
16     NSLog(@"%@", stringFromArray2);