IOS中NSSarry用法

標籤：des   blog   os   io   檔案   for   ar   div   

一、建立數組

// 建立一個空的數組  02.NSArray *array = [NSArray array];      03.// 建立有1個元素的數組  04.array = [NSArray arrayWithObject:@"123"];  05.// 建立有多個元素的數組  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、數組的基本用法

int count = [array count];//個數  02.// 判斷是否包含了某個元素  03.if ([array containsObject:@"a"]) {  04.    NSLog(@"包含了字串a");  05.}  06.NSString *last = [array lastObject];最後一個元素  07.NSString *str = [array objectAtIndex:1];根據索引擷取數組中的元素  08.int index = [array indexOfObject:@"c"];擷取指定元素的索引  09.// 讓數組裡面的所有對象都調用test方法，123為參數  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.// 利用分隔字元-拼接所有的數組元素  15.NSString *str = [array componentsJoinedByString:@"-"];  16.// 將一個數組寫入檔案（產生的是一個xml檔案）  17.NSString *path = @"/Users/apple/Desktop/array.xml";  18.[array writeToFile:path atomically:YES];  19.path = @"/Users/apple/Desktop/array.txt";  20.// 從檔案中讀取數組內容（檔案有嚴格的格式要求）  21.NSArray *array2 = [NSArray arrayWithContentsOfFile:path];  

 三、遍曆數組

#pragma mark 遍曆數組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 遍曆數組2 快速遍曆  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 遍曆數組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.         // 如果索引為1，就停止遍曆  29.         if (idx == 1) {  30.             // 利用指標修改外面BOOL變數的值  31.             *stop = YES;  32.         }  33.    }];  34.}  35.  36.#pragma mark 遍曆數組4  37.void arrayFor4() {  38.    Student *stu1 = [Student student];  39.    NSArray *array = [NSArray arrayWithObjects:stu1, @"1", @"2", @"3", nil nil];  40.    // 擷取數組的迭代器  41.    // NSEnumerator *enumerator = [array objectEnumerator];  42.    // 反序迭代器（從尾部開始遍曆元素）  43.    NSEnumerator *enumerator = [array reverseObjectEnumerator];  44.    // allObjects是取出沒有被遍曆過的對象  45.    NSArray *array2 = [enumerator allObjects];  46.    NSLog(@"array2:%@", array2);  47.    // 擷取下一個需要遍曆的元素  48.    id obj = nil;  49.    while (obj = [enumerator nextObject]) {  50.        NSLog(@"obj=%@", obj);  51.    }  52.}  

 

 

四、數組排序

#pragma mark 數組排序1  02.void arraySort1() {  03.    NSArray *array = [NSArray arrayWithObjects:@"2", @"3", @"1", @"4", nil nil];  04.      05.    // 返回一個排好序的數組，原來數組的元素順序不會改變  06.    // 指定元素的比較方法：compare:  07.    NSArray *array2 = [array sortedArrayUsingSelector:@selector(compare:)];  08.    NSLog(@"array2:%@", array2);  09.}  10.  11.#pragma mark 數組排序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.    // 指定排序的比較方法  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，就比較名字  26.    if (result == NSOrderedSame) {  27.        result = [self.firstname compare:stu.firstname];  28.    }  29.    return result;  30.}  31.  32.#pragma mark 數組排序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進行排序  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，就比較名字  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 數組排序4-進階排序  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.先按照書名進行排序  65.    // 這裡的key寫的是@property的名稱  66.    NSSortDescriptor *bookNameDesc = [NSSortDescriptor sortDescriptorWithKey:@"book.name" ascending:YES];  67.    // 2.再按照姓進行排序  68.    NSSortDescriptor *lastnameDesc = [NSSortDescriptor sortDescriptorWithKey:@"lastname" ascending:YES];  69.    // 3.再按照名進行排序  70.    NSSortDescriptor *firstnameDesc = [NSSortDescriptor sortDescriptorWithKey:@"firstname" ascending:YES];  71.    // 按順序添加排序描述器  72.    NSArray *descs = [NSArray arrayWithObjects:bookNameDesc, lastnameDesc, firstnameDesc, nil nil];  73.      74.    NSArray *array2 = [array sortedArrayUsingDescriptors:descs];  75.      76.    NSLog(@"array2:%@", array2);  77.}