Objective-C 数组一 "不可变数组"

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<pre name="code" class="objc">#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) {    @autoreleasepool {               //不可变数组 NSArray        //初始化        //创建一个空数组                NSArray *array1 = [[NSArray alloc] init];        NSArray *array2 = [NSArray alloc];                //创建一个里面有多个元素的不可变数组        NSArray *array3 = [NSArray arrayWithObject:@"Rick"];        NSLog(@"array3 = %@",array3);                //创建一个里面有多个元素的不可变数组        NSArray *array4 = [NSArray arrayWithObjects:@"zhengyongxai",@"zhengyongya",@"liutao",@"kuncai",nil];                //新语法        NSArray *array5 = @[@"Rick"];        NSArray *array6 = @[@"zhengyongxia",@"zhengyongya",@"liutao",@"kuncai"];        NSLog(@"array6 = %@",array6);                //根据另一个数组产生新的数组        NSArray *array7 = [NSArray arrayWithArray:array6];                        //从本地文件读取数组        NSArray *array8 = [NSArray arrayWithContentsOfFile:@"/Users/ibokan2/Desktop/hello.html"];        NSLog(@"%@",array8);                //从网络读取数组        NSURL *url = [NSURL URLWithString:@"www.baidu.com"];        NSArray *array9 = [NSArray arrayWithContentsOfURL:url];                        //求数组中的个数        NSUInteger count = array6.count;        NSLog(@"%count = ld",count);     // ount = ld                for (int i = 0; i < count; i++) {            NSString *str = [array6 objectAtIndex:i];   //objectAtIndex对象索引            NSLog(@"str[%d] = %@",i,str);        }                        //新语法访问数组中的元素        NSString *str2 = array6[0];        NSLog(@"str2 = %@",str2);   //str2 = zhengyongxia                        NSNumber *number1 = [NSNumber numberWithInt:5];   //NSNumber    number数量        //等价于        NSNumber *number2 = @5;        NSLog(@"umber1 = %@",number1);   //umber1 = 5                //通过数组中的元素找下标        NSUInteger index = [array6 indexOfObject:@"zhengyongxia"];   //indexOfObject 索引的对象        NSLog(@"index = %ld", index);     //index = 0        //如何判断数组中是否存在某个元素        bool flge = [array6 containsObject:@"zhengyongxia"];   //containsObject  包含数组        NSLog(@"flge = %d", flge);    //flge = 1                //向不可变数组中增加一个元素。产生新的不可变数组        NSArray *newArray1 = [array6 arrayByAddingObject:@"lihuitang"];   //arrayByAddingObject 通过添加对象数组        NSLog(@"newArray1 = %@",newArray1);                for (id obj in newArray1) {            NSLog(@"obj = %@", obj);        }                for (int i = 0; i < [newArray1 count]; i++) {            NSLog(@"newArray1 = %@",newArray1);        }                NSString *string = @"123-456-789";        NSArray *array11 = [string componentsSeparatedByString:@"-"];   //拆 -        NSLog(@"array11 = %@",array11);                NSArray *arr1 = [string stringByReplacingOccurrencesOfString:@"-" withString:@"~"];   //替换        NSLog(@"%@",arr1);                NSString *string11 = [newArray1 componentsJoinedByString:@"-"];    //添加 -        NSLog(@"string11 = %@",string11);                NSArray *array12 = @[@"123",@"456",@"789"];                NSString *array13 = [array12 componentsJoinedByString:@"--"];        NSLog(@"array13 = %@",array13);                NSArray *array14 = [array13 componentsSeparatedByString:@"--"];    //拆        NSLog(@"array14 = %@",array14);//         array14 = (//                     123,//                     456,//                     789//                 )                        NSString *string12 = [array14 componentsJoinedByString:@""];        NSLog(@"string12 = %@",string12);   //string12 = 123456789        /*         使用NSArray 类注意事项         1、数组越界，当访问NSArray 时，索引超出元素个数之后报出一个异常结果。所以最好检查一下索引结果是否越界，然后在进行调用         2、数组会对加入其中的对象自动把引用计数加一         3、不能在数组中间存放nil，nil只能出现在数组的最后，因为nil是一个NSArray 结束的标志         */            }    return 0;}
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