Objective-C 入门篇(推荐)

//字符串
NSString *str1 = @"ABC3456789";
//拼接成新的字符串
 NSString *str2 = [str1 stringByAppendingString:@"wwww"];
NSLog(@"str = %@", str2);
//遍历
for (int i = 0; i < [str2 length]; i++) {
    char temp = [str2 characterAtIndex:i];
    NSLog(@"字符串第 %d 位输出 %c", i, temp);
}
//比较
// sEqualToString方法 ：比较字符串是否完全相等，大小写不一样也无法完全匹配。
//hasPrefixe方法：逐一匹配字符串头部。haSuffix方法：匹配字符串的尾部
if ([str2 isEqualToString:str1]) {
    NSLog(@"相等");
}
if ([str2 hasPrefix:@"www"]) {
    NSLog(@"有该头部");
}
if ([str2 hasSuffix:@"www"]) {
    NSLog(@"有该尾部");
}
if ([str2 compare:str options:NSCaseInsensitiveSearch | NSNumericSearch] == NSOrderedSame) {
}
NSLog(@"比较结果：%d", [str2 caseInsensitiveCompare:str1]);
//大小写转换
NSLog(@"str3转大写：%@",[str2 uppercaseString]);
NSLog(@"str3转小写：%@",[str2 lowercaseString]);
NSLog(@"str3首字母转大写：%@",[str2 capitalizedString]);
//字符串截取
NSRange rang = NSMakeRange(2, 2);
NSLog(@"str3截取：%@",[str2 substringWithRange:rang]);
//搜索
NSRange rang1 = [str2 rangeOfString:@"www"];
NSLog(@"location: %d,length: %d",rang1.location,rang1.length);
//替换
//全部替换
NSString *str3 = [str2 stringByReplacingOccurrencesOfString:@" " withString:@"@"];
NSLog(@"替换后字符串为%@", str3);
//局部替换
NSString *str4 = [str2 stringByReplacingCharactersInRange:rang withString:@"met"];
NSLog(@"替换后字符串为%@", str4);

		//创建对象并初始化
		NSMutableString *mStr = [[NSMutableString alloc]init];
        //appendstring：向字符串尾部添加一个字符串。
        //appendFormat：向字符串尾部添加多个类型的字符串，可以添加任意数量与类型的字符串。
        [mStr appendString:@"hello world!"];
        NSLog(@"字符串创建%@", mStr);
        [mStr deleteCharactersInRange:[mStr rangeOfString:@"hello"]];
        //删除
        NSLog(@"字符串删除%@", mStr);
        //插入
        [mStr insertString:@"love you" atIndex: mStr.length];
        NSLog(@"字符串插入%@", mStr);

//包装
NSNumber *intNumber = [[NSNumber alloc]initWithInt:43];
//或者字面量方式
NSNumber *intNumber1 = @43;
//还原基本数据类型，解包
NSLog(@"%d",[intNumber intValue]);

//字面量创建方式
    NSArray *arr2 = @[@"aaa",@"bbbbb"];
//工厂方法创建
    NSArray *array = [[NSArray alloc] initWithObjects:@"1", @"2", nil];
    //取最后一个元素
    [array lastObject];
//    取第一个元素
    [array firstObject];
//    数组是否包含某个元素
    [array containsObject:@"1"];
//    数组的大小
    int count = (int) array.count;
//    第一种方式遍历
    for (int i = 0; i < count; i++) {
        NSString *_str = [array objectAtIndex:i];
    }

// 字面量创建二维数组并访问
NSArray *arr2 = @[@[@11, @12, @13], @[@21, @22, @23], @[@31, @32, @33]];
// 字面量访问方式(推荐)
NSLog(@"arr2[2][2]:%@", arr2[2][2]);
// 数组对象函数访问
NSLog(@"arr2[2][2]:%@", [[arr2 objectAtIndex:2] objectAtIndex:2]);

		//创建，当然还有其他方式
        NSMutableArray *mutableArr = [NSMutableArray arrayWithObjects:@"one",@"two",@"three", nil];
        //添加
        [mutableArr addObject:@"hello"];
        //替换
        [mutableArr replaceObjectAtIndex:2 withObject:@"tihuan"];
        //删除
        [mutableArr removeObjectAtIndex:1];
        //插入
        [mutableArr insertObject:@"ios" atIndex:1];

   		// 初始化作为列的数组，看做4列
NSMutableArray *columnArray = [[NSMutableArray alloc]initWithCapacity:4];

// 初始化2个一维数组，每个一维数组有4个元素，看做1行4列，2行加起来就是2行4列
NSMutableArray *rowArray1 = [[NSMutableArray alloc]initWithCapacity:4];
NSMutableArray *rowArray2 = [[NSMutableArray alloc]initWithCapacity:4];

// 每个行依次增加数组元素
// 第一行
[rowArray1 addObject:@"11"];
[rowArray1 addObject:@"12"];
[rowArray1 addObject:@"13"];
[rowArray1 addObject:@"14"];

// 第二行
[rowArray2 addObject:@"21"];
[rowArray2 addObject:@"22"];
[rowArray2 addObject:@"23"];
[rowArray2 addObject:@"24"];

// 分别打印数组
NSLog(@"myRowArray1: %@", rowArray1);
NSLog(@"myRowArray2: %@", rowArray2);
NSLog(@"myColumnArray: %@", columnArray);

	//标准创建
    NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"cat",@"name1",@"dog",@"name2", nil];
    //字面量创建
    NSDictionary *dict1 = @{@"name1":@"cat",@"name2":@"dog"};
	//第一种遍历
    for (NSString *key in [dict1 allKeys]) {
        NSLog(@"key: %@,value: %@", key, dict1[key]);
    }
    //第二种遍历方式，通过遍历器
    NSEnumerator *rator = [dict keyEnumerator];
    NSString *temp;
    while (temp = [rator nextObject]) {
        NSLog(@"%@", temp);
    }
    //获取元素
	dict1[@"name"];
	[dict1 objectForKey:@"name"];
	//集合元素的个数
	NSInteger count = dict1.count;
	//沙盒文件存储和读取Plist
	[dict5 writeToFile:@"路径" atomically:YES];
	NSDictionary *dict7 = [NSDictionary dictionaryWithContentsOfFile:@"路径"];

//创建
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
//添加
[dict setObject:@"dog" forKey:@"name"];
[dict setValue:@"18" forKey:@"age"];
//会将传入字典中所有的键值对取出来添加到dict中
[dict setValuesForKeysWithDictionary:@{@"name1":@"dog"}];
//取元素
[dict objectForKey:@"name"];
dict[@"name"];
//删除
[dict removeAllObjects];
[dict removeObjectForKey:@"name"];
[dict removeObjectsForKeys:@[@"name", @"age"]];
//更新，如果利用setObject方法给已经存在的key赋值，新值会覆盖旧值
[dict setObject:@"20" forKey:@"age"];
dict[@"age"] = @"30";

NSString *sourceString = [NSString stringWithFormat:@"hello ios"];
//不产生新的内存空间
NSString *copyStr = [sourceString copy];
//产生新的内存空间
NSMutableString *mutableStr = [sourceString mutableCopy];
NSLog(@"sourceString : %@   %p",sourceString,sourceString);
NSLog(@"copyStr : %@    %p",copyStr,copyStr);
NSLog(@"mutableStr : %@     %p",mutableStr,mutableStr);