【IOS初学者】数组与字典

在这里我要说一下，ios开发的知识点都偏于基础，我只记录了一些基础的知识点，并进行了扩展，适合入门的朋友：
【IOS初学者】UITableView与自定义UITableViewCell
【IOS初学者】bundle知识点总结
【IOS开发初学者】UINavigationController详解

---

NSArray

初始化

//1)建立一个空数组
    NSArray *arr1 = [NSArray array];
    //建立数组,只有一个元素
    NSArray *arr2 = [NSArray arrayWithObject:@"aaa"];
    //建立数组,有多个元素
    // nil 表示数组赋值结束
    NSArray *arr3 = [NSArray arrayWithObjects:@"aaa",@"bbb", nil];
    //调用对象方法,建立数组
    NSArray *arr4 = [[NSArray alloc] initWithObjects:@"aaa",@"bbb", nil];
    //用一个数组能够建立另一个数组
    NSArray *arr5 = [NSArray arrayWithArray:arr3];
    //使用@
    NSArray *arr6 = @[@"aaa",@"bbb",@"ccc",@"ddd"];复制代码

经常使用方法

//获取数组的长度
    NSLog(@"%ld",arr3.count);
    //根据下标,获取下标对应的对象
    NSLog(@"%@",[arr3 objectAtIndex:1]);  
    NSLog(@"%@",arr3[1]);
    //返回元素的下标
    NSUInteger loc = [arr3 indexOfObject:@"bbb"];
    NSLog(@"%ld",loc);
    //数组中是否包含了某个元素
    if([arr3 containsObject:@"gggg"]){     
        NSLog(@"包含此元素");
    }else{
        NSLog(@"不包含");
    }
    NSLog(@"arr5 = %@",arr5);复制代码

对应log：

2017-02-24 09:35:12.836 TestArray[7023:601929] 2
2017-02-24 09:35:12.837 TestArray[7023:601929] bbb
2017-02-24 09:35:12.837 TestArray[7023:601929] bbb
2017-02-24 09:35:12.837 TestArray[7023:601929] 1
2017-02-24 09:35:12.837 TestArray[7023:601929] 不包含
2017-02-24 09:35:12.837 TestArray[7023:601929] arr5 = (
    aaa,
    bbb
)复制代码

遍历

//普通的方式,经过下标访问
    for (int i=0; i<arr3.count; i++) {
        NSLog(@"-> %@",arr3[i]);
    }

    // 快速枚举法 for循环的加强形式
    for (NSString * str in arr3) {
        NSLog(@"---> %@",str);
    }


    //使用block的方式,进行访问
    [arr3 enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {

        if(idx == 2){

            *stop = YES;  //中止

        }else{

            NSLog(@"idx = %ld,obj = %@",idx,obj);
        }


    }];复制代码

打印log以下：

2017-02-24 09:46:33.215 TestArray[7047:609202] -> aaa
2017-02-24 09:46:33.215 TestArray[7047:609202] -> bbb
2017-02-24 09:46:33.215 TestArray[7047:609202] ---> aaa
2017-02-24 09:46:33.215 TestArray[7047:609202] ---> bbb
2017-02-24 09:46:33.215 TestArray[7047:609202] idx = 0,obj = aaa
2017-02-24 09:46:33.215 TestArray[7047:609202] idx = 1,obj = bbb
Program ended with exit code: 0复制代码

读写

• 写

NSArray *array = [NSArray     arrayWithObjects:@"one",@"zbz",@"cgx",@"sb",@"cjk",@"senni", nil];
 BOOL isWrite =  [array writeToFile:@"/Users/xxxx/Desktop/arr.xml" atomically:YES];复制代码

• 读

NSArray *readArr = [NSArray arrayWithContentsOfFile:@"/Users/xxxx/Desktop/arr.xml"];复制代码

NSArray与字符串

• 数组拼接字符串

NSArray *arr6 = @[@"aaa",@"bbb",@"ccc",@"ddd"];
    NSString *str = [arr6 componentsJoinedByString:@"-"];
    NSLog(@"str = %@",str);复制代码

• 字符串拆分为数组

NSArray *arr7 = [str componentsSeparatedByString:@"-"];
    NSLog(@"%@",[arr7 firstObject]);
    NSLog(@"%@",[arr7 lastObject]);
    NSLog(@"%@",arr7[1]);复制代码

看下打印log：

2017-02-24 09:58:04.852 TestArray[7107:619117] str = aaa-bbb-ccc-ddd
2017-02-24 09:58:04.852 TestArray[7107:619117] aaa
2017-02-24 09:58:04.853 TestArray[7107:619117] ddd
2017-02-24 09:58:04.853 TestArray[7107:619117] bbb
Program ended with exit code: 0复制代码

NSMutableArray

初始化

NSMutableArray *arr1 = [NSMutableArray array];
    //建立的时候初始化一个元素
    NSMutableArray *arr2 = [NSMutableArray arrayWithObject:@"aaa"];

    //建立数组的时候,初始化多个元素
    NSMutableArray *arr3 = [NSMutableArray arrayWithObjects:@"bbb",@"ccc",@"ddd",nil];

    //建立一个数组,而且指定长度,
    NSMutableArray *arr4 = [NSMutableArray arrayWithCapacity:5];复制代码

操做

• 添加

  [arr1 addObject:@"ccc"];
  [arr1 insertObject:@"ddd" atIndex:0];复制代码

• 删除

  /删除指定元素
  [arr1 removeObject:@"aaa"];
  //根据角标删除元素
  [arr1 removeObjectAtIndex:1];
  //删除全部元素
  [arr1 removeAllObjects];复制代码

• 修改

  [arr3 replaceObjectAtIndex:1 withObject:@"aaa"];
  arr3[1] = @"ccc";复制代码

• 查找

  BOOL isSearch = [arr3 containsObject:@"ddd"];
  NSLog(@"%d",isSearch);复制代码

• 交换

  NSMutableArray *arr5 =[NSMutableArray arrayWithObjects:@1,@2,@3,@4,@5, nil];
  [arr5 exchangeObjectAtIndex:0 withObjectAtIndex:4];
  NSLog(@"%@",arr5);复制代码

  遍历

  NSMutableArray的遍历能够使用NSArray的方式进行遍历

NSDictionary

建立

NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"lnj", @"name", @"12345678", @"phone", @"天朝", @"address", nil];

NSDictionary *dict = @{@"name":@"lnj", @"phone":@"12345678", @"address":@"天朝"};复制代码

获取元素

[dict objectForKey:@"name”];
dict[@"name”];复制代码

遍历

NSDictionary *dict = @{@"name":@"lnj", @"phone":@"12345678", @"address":@"天朝"};
    for (NSString *key in dict) {
        NSLog(@"key = %@, value = %@", key, dict[key]);
    }复制代码

或

[dict enumerateKeysAndObjectsUsingBlock:^(NSString *key, NSString *obj, BOOL *stop) {
        NSLog(@"key = %@, value = %@", key, obj);
    }];复制代码

读写

• 读

  NSDictionary *newDict = [NSDictionary dictionaryWithContentsOfFile:@"/Users/LNJ/Desktop/dict.plist"];
    NSLog(@"newDict = %@", newDict);复制代码

• 写

  NSDictionary *dict = @{@"name":@"lnj", @"phone":@"12345678", @"address":@"天朝"};
    BOOL flag = [dict writeToFile:@"/Users/LNJ/Desktop/dict.plist" atomically:YES];
    NSLog(@"flag = %i", flag);复制代码

NSMutableDictionary

初始化

NSMutableDictionary *dic2 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"v1",@"key1",@"v2",@"key2",nil];
 NSMutableDictionary *dict1 = [NSMutableDictionary dictionary]; 
  NSMutableDictionary *dict2 = [NSMutableDictionary dictionaryWithCapacity:3];复制代码

添加元素

[dic2 addEntriesFromDictionary:dic3];
[dic2 setValue:@"value3" forKey:@"key3"];复制代码

删除元素

//删除指定key
[dic1 removeObjectForKey@"key1"];
//删除指定key数组
NSArray *array = [NSArray arrayWithObjects:@"key1", nil];
[dic2 removeObjectsForKeys:array];
//移除字典全部对象
[dic1 removeAllObjects];复制代码

修改元素

[dict1 setObject:@"zhaosi" forKey:@"ls"];
  //简写形式
  dict1[@"ls"] = @"xxxxx";
   NSLog(@"%@",dict1);复制代码

遍历

NSMutableDictionary *dictionary3 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"value",@"key",@"value2",@"key2",@"value3",@"key3",@"value4",@"key4",@"value5",@"key5",@"value6",@"key6", nil];
        for (id key in dictionary3) {
            id obj = [dictionary3 objectForKey:key];

            NSLog(@"快速枚举--->obj= %@",obj);
        }

        //通常枚举
        NSArray *keys = [dictionary3 allKeys];
        float length = [keys count];
        for (int i = 0; i < length; i ++) {
            id key = [keys objectAtIndex:i];
            id obj = [dictionary3 objectForKey:key];
            NSLog(@"通常枚举--->%@",obj);
        }

        //经过枚举类枚举
        NSEnumerator *enumerator3 = [dictionary3 keyEnumerator];
        id key = [enumerator3 nextObject];
        while (key) {
            id obj = [dictionary3 objectForKey:key];
            NSLog(@"经过枚举类枚举--->%@",obj);
            key = [enumerator3 nextObject];
        }复制代码