IOS中NSSarry用法

一、创建数组

// 创建一个空的数组  
02.NSArray *array = [NSArray array];      
03.// 创建有1个元素的数组  
04.array = [NSArray arrayWithObject:@"123"];  
05.// 创建有多个元素的数组  
06.array = [NSArray arrayWithObjects:@"a", @"b", @"c", nil nil];  
07.NSArray *array3 = [array arrayByAddingObjectsFromArray:[NSArray arrayWithObjects:@"4", @"5", nil nil]];  
08.  
09.NSArray *array4 = [NSArray arrayWithObjects:@"1", @"2", @"3", @"4", nil nil];  
10.NSRange range = NSMakeRange(1, 2);  
11.NSArray *array5 = [array4 subarrayWithRange:range];  

二、数组的基本用法

int count = [array count];//个数  
02.// 判断是否包含了某个元素  
03.if ([array containsObject:@"a"]) {  
04.    NSLog(@"包含了字符串a");  
05.}  
06.NSString *last = [array lastObject];最后一个元素  
07.NSString *str = [array objectAtIndex:1];根据索引获取数组中的元素  
08.int index = [array indexOfObject:@"c"];获取指定元素的索引  
09.// 让数组里面的所有对象都调用test方法，123为参数  
10.NSArray *array = [NSArray arrayWithObjects:stu1, stu2, stu3, nil nil];  
11.[array makeObjectsPerformSelector:@selector(test2:) withObject:@"123"];  
12.NSArray *array = [NSArray arrayWithObjects:@"1", @"2", @"3", @"4", nil nil];  
13.// 1-2-3-4  
14.// 利用分隔符-拼接所有的数组元素  
15.NSString *str = [array componentsJoinedByString:@"-"];  
16.// 将一个数组写入文件（生成的是一个xml文件）  
17.NSString *path = @"/Users/apple/Desktop/array.xml";  
18.[array writeToFile:path atomically:YES];  
19.path = @"/Users/apple/Desktop/array.txt";  
20.// 从文件中读取数组内容（文件有严格的格式要求）  
21.NSArray *array2 = [NSArray arrayWithContentsOfFile:path];  

 三、遍历数组

#pragma mark 遍历数组1  
02.void arrayFor1() {  
03.    NSArray *array = [NSArray arrayWithObjects:stu1, @"1", @"2", @"3", nil nil];  
04.    int count = array.count;  
05.    for (int i = 0; i<count; i++) {  
06.        id obj = [array objectAtIndex:i];  
07.    }  
08.}  
09.  
10.#pragma mark 遍历数组2 快速遍历  
11.void arrayFor2() {  
12.    Student *stu1 = [Student student];  
13.    NSArray *array = [NSArray arrayWithObjects:stu1, @"1", @"2", @"3", nil nil];  
14.    int i =0;  
15.    for (id obj in array) {  
16.        NSLog(@"%i-%@", i, obj);  
17.        i++;  
18.    }  
19.}  
20.  
21.#pragma mark 遍历数组3  
22.void arrayFor3() {  
23.    Student *stu1 = [Student student];  
24.    NSArray *array = [NSArray arrayWithObjects:stu1, @"1", @"2", @"3", nil nil];  
25.    [array enumerateObjectsUsingBlock:  
26.     ^(id obj, NSUInteger idx, BOOLBOOL *stop) {  
27.        NSLog(@"%i-%@", idx, obj);  
28.         // 如果索引为1，就停止遍历  
29.         if (idx == 1) {  
30.             // 利用指针修改外面BOOL变量的值  
31.             *stop = YES;  
32.         }  
33.    }];  
34.}  
35.  
36.#pragma mark 遍历数组4  
37.void arrayFor4() {  
38.    Student *stu1 = [Student student];  
39.    NSArray *array = [NSArray arrayWithObjects:stu1, @"1", @"2", @"3", nil nil];  
40.    // 获取数组的迭代器  
41.    // NSEnumerator *enumerator = [array objectEnumerator];  
42.    // 反序迭代器（从尾部开始遍历元素）  
43.    NSEnumerator *enumerator = [array reverseObjectEnumerator];  
44.    // allObjects是取出没有被遍历过的对象  
45.    NSArray *array2 = [enumerator allObjects];  
46.    NSLog(@"array2:%@", array2);  
47.    // 获取下一个需要遍历的元素  
48.    id obj = nil;  
49.    while (obj = [enumerator nextObject]) {  
50.        NSLog(@"obj=%@", obj);  
51.    }  
52.}  

四、数组排序

#pragma mark 数组排序1  
02.void arraySort1() {  
03.    NSArray *array = [NSArray arrayWithObjects:@"2", @"3", @"1", @"4", nil nil];  
04.      
05.    // 返回一个排好序的数组，原来数组的元素顺序不会改变  
06.    // 指定元素的比较方法：compare:  
07.    NSArray *array2 = [array sortedArrayUsingSelector:@selector(compare:)];  
08.    NSLog(@"array2:%@", array2);  
09.}  
10.  
11.#pragma mark 数组排序2  
12.void arraySort2() {  
13.    Student *stu1 = [Student studentWithFirstname:@"MingJie" lastname:@"Li"];  
14.    Student *stu2 = [Student studentWithFirstname:@"LongHu" lastname:@"Huang"];  
15.    Student *stu3 = [Student studentWithFirstname:@"LianJie" lastname:@"Li"];  
16.    Student *stu4 = [Student studentWithFirstname:@"Jian" lastname:@"Xiao"];  
17.    NSArray *array = [NSArray arrayWithObjects:stu1,stu2,stu3, stu4, nil nil];  
18.    // 指定排序的比较方法  
19.    NSArray *array2 = [array sortedArrayUsingSelector:@selector(compareStudent:)];  
20.    NSLog(@"array2:%@", array2);  
21.}  
22.- (NSComparisonResult)compareStudent:(Student *)stu {  
23.    // 先按照姓排序  
24.    NSComparisonResult result = [self.lastname compare:stu.lastname];  
25.    // 如果有相同的姓，就比较名字  
26.    if (result == NSOrderedSame) {  
27.        result = [self.firstname compare:stu.firstname];  
28.    }  
29.    return result;  
30.}  
31.  
32.#pragma mark 数组排序3  
33.void arraySort3() {  
34.    Student *stu1 = [Student studentWithFirstname:@"MingJie" lastname:@"Li"];  
35.    Student *stu2 = [Student studentWithFirstname:@"LongHu" lastname:@"Huang"];  
36.    Student *stu3 = [Student studentWithFirstname:@"LianJie" lastname:@"Li"];  
37.    Student *stu4 = [Student studentWithFirstname:@"Jian" lastname:@"Xiao"];  
38.    NSArray *array = [NSArray arrayWithObjects:stu1,stu2,stu3, stu4, nil nil];  
39.      
40.    // 利用block进行排序  
41.    NSArray *array2 = [array sortedArrayUsingComparator:  
42.     ^NSComparisonResult(Student *obj1, Student *obj2) {  
43.         // 先按照姓排序  
44.         NSComparisonResult result = [obj1.lastname compare:obj2.lastname];  
45.         // 如果有相同的姓，就比较名字  
46.         if (result == NSOrderedSame) {  
47.             result = [obj1.firstname compare:obj2.firstname];  
48.         }  
49.           
50.         return result;  
51.    }];  
52.      
53.    NSLog(@"array2:%@", array2);  
54.}  
55.  
56.#pragma mark 数组排序4-高级排序  
57.void arraySort4() {  
58.    Student *stu1 = [Student studentWithFirstname:@"MingJie" lastname:@"Li" bookName:@"book1"];  
59.    Student *stu2 = [Student studentWithFirstname:@"LongHu" lastname:@"Huang" bookName:@"book2"];  
60.    Student *stu3 = [Student studentWithFirstname:@"LianJie" lastname:@"Li" bookName:@"book2"];  
61.    Student *stu4 = [Student studentWithFirstname:@"Jian" lastname:@"Xiao" bookName:@"book1"];  
62.    NSArray *array = [NSArray arrayWithObjects:stu1,stu2,stu3, stu4, nil nil];  
63.      
64.    // 1.先按照书名进行排序  
65.    // 这里的key写的是@property的名称  
66.    NSSortDescriptor *bookNameDesc = [NSSortDescriptor sortDescriptorWithKey:@"book.name" ascending:YES];  
67.    // 2.再按照姓进行排序  
68.    NSSortDescriptor *lastnameDesc = [NSSortDescriptor sortDescriptorWithKey:@"lastname" ascending:YES];  
69.    // 3.再按照名进行排序  
70.    NSSortDescriptor *firstnameDesc = [NSSortDescriptor sortDescriptorWithKey:@"firstname" ascending:YES];  
71.    // 按顺序添加排序描述器  
72.    NSArray *descs = [NSArray arrayWithObjects:bookNameDesc, lastnameDesc, firstnameDesc, nil nil];  
73.      
74.    NSArray *array2 = [array sortedArrayUsingDescriptors:descs];  
75.      
76.    NSLog(@"array2:%@", array2);  
77.}