NSArray - 數組

NSArray - 數組

//
//  main.m
//  OC04-task-07
//
//  Created by Xin the Great on 15-1-24.
//  Copyright (c) 2015年 Xin the Great. All rights reserved.
//

#import 
#import "NSArray+Log.h"
#import "Person.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        
        ///////////////NSArray - 數組///////////////
        //數組的創建, 使用alloc init創建和使用類方法創建功效是一樣的，但是內存管理上不同
        NSArray *arr1 = [[NSArray alloc] initWithObjects:@"1",@"2", nil];
        NSLog(@"arr1 is %@",arr1);
        //類方法創建
        NSArray *arr2 = [NSArray arrayWithObjects:@"11",@"22", nil];
        NSLog(@"arr2 is %@",arr2);
        //此初始化方法使arr3只有一個元素
        NSArray *arr3 = [NSArray arrayWithObject:@"我們在學IOS"];
        NSLog(@"arr3 is %@",arr3);
        
        //創建一個人的對象
        Person *jack = [[Person alloc] init];
        jack.name = @"jack";
        jack.age = 30;
        NSArray *arr4 = [NSArray arrayWithObject:jack];
        NSLog(@"arr4 is %@",arr4);
        
        //通過已有的數組構造一個新的數組
        NSArray *newArray = [NSArray arrayWithArray:arr2];
        NSLog(@"newArray is %@",newArray);


        
        //數組的訪問
        //objectAtIndex: 根據下標取出元素,如果下標越界，程序崩潰（crash）
        Person *jack1 = [arr4 objectAtIndex:0];
        NSLog(@"jack1 is %@",jack1);
        
        //通過元素取下標, 如果沒有找到，則返回NSNotFound
        NSArray *arr5 = [NSArray arrayWithObjects:@"1",@"2",jack, nil];
//        NSInteger index = [arr5 indexOfObject:jack];
//        NSLog(@"index is %ld", index);
        NSInteger index = [arr5 indexOfObject:@"123"];
        NSLog(@"index is %ld", index);
        
        //求數組的長度
        NSInteger count = [arr5 count];
        NSLog(@"count is %ld", count);
        
        //判斷數組中是否存在某一個元素,
        BOOL isTrue = [arr5 containsObject:@"123"];
        NSLog(@"isTrue is %d",isTrue);
        
        //將數組變成一個字符串
        NSArray *arr6 = [NSArray arrayWithObjects:@"1",@"2",@"3",@"4",@"5", nil];
        NSString *str = [arr6 componentsJoinedByString:@"-"];
        NSLog(@"str is %@",str);
        //將字符串分割成數組
        NSArray *arr7 = [str componentsSeparatedByString:@"-"];
        NSLog(@"arr7 is %@",arr7);
        
        //獲取第一個元素和最後一個元素
        NSString *firstStr = arr7[0];
        NSLog(@"firstStr is %@",firstStr);
//        NSString *lastStr = arr7[arr7.count - 1];
        //最後一個元素
        NSString *lastStr = [arr7 lastObject];
        NSLog(@"lastStr is %@",lastStr);

        //簡單寫法
        NSArray *arr8 = @[jack, @"2"];
        
        NSString *value = arr8[0];
        NSLog(@"value is %@",value);
        
    }
    return 0;
}