iOS中NSArray数组常用处理方式

//--------------------不可变数组//1.数组的创建NSString *s1 = @"zhangsan";NSString *s2 = @"lisi";NSString *s3 = @"wangwu";//(1)NSArray *array1 = [[NSArray alloc] initWithObjects:s1,s2,s3, nil];NSLog(@"%@",array1); //等价于 array1.descripton//(2)使用类方法创建NSArray *array2 = [NSArray arrayWithObjects:s1,s2,s3, nil];//(3)创建一个数组对象，同时往里面存入一元素NSArray *array3 = [NSArray arrayWithObject:s1];//(4)创建一个数组，此数组中的元素来自array1NSArray *array4 = [NSArray arrayWithArray:array1];NSLog(@"array4 = %@",array4);//2.通过下标取元素NSString *str1 = [array4 objectAtIndex:0];//3.数组元素的个数NSUInteger count = [array4 count]; //等价于：array4.count;//4.判断数组中的是否包含某个元素BOOL isContains = [array4 containsObject:@"zhangsan"];NSLog(@"isContains:%d",isContains);//5.查找某一个对象在数组中的下标位置NSUInteger index = [array4 indexOfObject:@"wangwu"];if (index == NSNotFound) {NSLog(@"Not find elemnts");} else {NSLog(@"index = %ld",index);}//6.链接数组中的字符串(前提：数组中都是字符串）NSString *joinString = [array4 componentsJoinedByString:@","];NSLog(@"joinString = %@",joinString);//7.访问数组最后一个元素NSString *lastObj = [array4 lastObject]; //array4.lastObjectNSLog(@"lsatObj = %@",lastObj);//8.再原路的数组后面添加一个元素NSArray *array5 = [array4 arrayByAddingObject:@"zhaolia"];NSLog(@"array5 = %@",array5);//取对应下标元素int idx=4;if (idx <array5.count) {NSString *s = [array5 objectAtIndex:idx];NSLog(@"s = %@",s);}//--------------数组的遍历//1.普通遍历for (int i=0; i<array5.count; i++) {NSString *str = [array5 objectAtIndex:i];NSLog(@"%@",str);}//快速遍历for (NSString *s in array5) {NSLog(@"%@",s);}//4.4之后的优化//1.创建一个素组NSArray *array7 = @[s1,s2,s3]; //等价于：NSArray *array7 = [NSArray arrayWithObjects:s1,s2,s3,nil];NSLog(@"array7 = %@",array7);NSString *str = array7[0];NSLog(@"array[7] = %@",str);//------------------可变数组//初始化，设定元素个数为5，可以更改的。（继承自NSArray）NSMutableArray *mutableArray = [NSMutableArray arrayWithCapacity:5];//想数组中添加一个元素[mutableArray addObject:@"aaa"];//向数组中指定下标插入元素[mutableArray insertObject:@"ccc" atIndex:0];NSLog(@"%@",mutableArray); //原来位置元素后移//移除最后一个元素[mutableArray removeLastObject];NSLog(@"移除最后元素后：%@",mutableArray);//移除指定元素[mutableArray removeObject:@"aaa"];//移除指定下标元素[mutableArray removeObjectAtIndex:0];//向数组中添加数组[mutableArray addObjectsFromArray:array1];//1.创建可变数组NSString *t1 = @"zhangsan ";NSString *t2 = @"lisi";NSString *t3 = @"wangwu ";// NSMutableArray *mArray1 = @[s1,s2,s3];//wrong.这里创建了一个不可变数组NSMutableArray *mArray1 = [[NSMutableArray alloc] initWithObjects:s1,s2,s3, nil];//创建数组时，开辟3个空间用于存储元素，存储超过容量，数组自动增大空间NSMutableArray *mArray2 = [[NSMutableArray alloc] initWithCapacity:3];NSMutableArray *mArray3 = [NSMutableArray arrayWithCapacity:3];//2.添加元素[mArray2 addObject:t1];[mArray2 addObject:t2];[mArray2 addObject:t3];NSLog(@"mArray2= %@",mArray2);//将mArray2 中元素添加到mArray3中// [mArray3 addObjectsFromArray:mArray2];//将mArray2作为二维数字添加[mArray3 addObject:mArray2];NSLog(@"mArray3 = %@",mArray3);//3.插入元素[mArray2 insertObject:@"Jack" atIndex:0];NSLog(@"mArray2 = %@",mArray2);//4.替换元素[mArray2 replaceObjectAtIndex:0 withObject:@"John"];NSLog(@"替换：%@",mArray2);//5.互换两个元素的位置[mArray2 exchangeObjectAtIndex:3 withObjectAtIndex:0];NSLog(@"mArray2 = %@",mArray2);//6.删除元素//6.1根据下标删除[mArray2 removeObjectAtIndex:2];NSLog(@"mArray2 = %@",mArray2);//6.2删除最后一个元素[mArray2 removeLastObject];NSLog(@"mArray2 = %@",mArray2);//6.3删除指定的对象//[mArray2 removeObject:@"zhangsan"];//6.4删除所有元素[mArray2 removeAllObjects];NSLog(@"mArray2 = %@",mArray2);