iPhone编码中如何将字符串的值添加到哈希表中？

发布于 2024-08-21 00:00:05 字数 705 浏览 3 评论 0原文

for(NSString *s in mainarr)
 {
    NSString newseparator = @"="; 
    NSArray *subarray = [s componentsSeparatedByString : newseparator]; 

  //Copying the elements of array into key and object string variables 

    NSString *key = [subarray objectAtIndex:0]; 
    NSLog(@"%@",key); 
    NSString *class_name= [subarray objectAtIndex:1]; 
    NSLog(@"%@",class_name); 

  //Putting the key and objects values into hashtable  
    NSDictionary *dict= [NSDictionary dictinaryWithObject:@"class_name" forKey:@"key"];
 }

你好..在上面的代码中，我必须在 for 循环中解析数组的元素，然后必须将子字符串键和 class_name 放入哈希表中。如何将这些字符串变量的值放入哈希表中。在上面的代码中，我猜变量 class_name 和 key 被放入哈希表中，而不是值。我想这是一个错误的方法。可以做什么来实现解决方案？

原文

for(NSString *s in mainarr)
 {
    NSString newseparator = @"="; 
    NSArray *subarray = [s componentsSeparatedByString : newseparator]; 

  //Copying the elements of array into key and object string variables 

    NSString *key = [subarray objectAtIndex:0]; 
    NSLog(@"%@",key); 
    NSString *class_name= [subarray objectAtIndex:1]; 
    NSLog(@"%@",class_name); 

  //Putting the key and objects values into hashtable  
    NSDictionary *dict= [NSDictionary dictinaryWithObject:@"class_name" forKey:@"key"];
 }

Hello.. in the above code i ve to parse the elements of array in a for loop, and then have to put the substring key and class_name into a hashtable. how to put a value of those string variables into hashtable.
in the code above i guess the variables class_name and key are put into hashtable not the value. i suppose its a wrong method. wat can be done to achieve the solution?

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烧了回忆取暖 2024-08-28 00:00:05

但您应该编写。

 NSString* newseparator = @"=";

(1)，尽管直接使用

 NSArray *subarray = [s componentsSeparatedByString:@"="];

要好得多（或将 newseparator 设为全局常量），

(2)，您的最后一条语句

    NSMutableDictionary = [NSDictionary dictinaryWithObject:@"class_name" forKey:@"key"];

无效，因为 (a) NSMutableDictionary 是一种类型； (b) 您正在创建字典，而不是可变字典； (c) 您每次都创建它，并覆盖以前的； (d) 您正在使用常量值 @"class_name" 和键 @"key" 创建字典，该字典与实际变量 class_name< /code> 和 key。

要将键值对添加到 1 个哈希表中，您应该在开头创建可变字典

NSMutableDictionary* dict = [NSMutableDictionary dictionary];

，然后在循环中使用 -setObject:forKey: 将其添加到字典中：

[dict setObject:class_name forKey:key];

总而言之，你应该将代码修改为

NSMutableDictionary* dict = [NSMutableDictionary dictionary];
for(NSString *s in mainarr) {
    NSArray *subarray = [s componentsSeparatedByString:@"="]; 

    // Get the elements of array into key and object string variables 
    NSString *key = [subarray objectAtIndex:0]; 
    NSLog(@"%@",key); 
    NSString *class_name= [subarray objectAtIndex:1]; 
    NSLog(@"%@",class_name); 

    //Putting the key and objects values into hashtable  
    [dict setObject:class_name forKey:key];
}    
return dict;

(1), You should write

 NSString* newseparator = @"=";

although directly using

 NSArray *subarray = [s componentsSeparatedByString:@"="];

is much better (or make newseparator a global constant).

(2), Your last statement,

    NSMutableDictionary = [NSDictionary dictinaryWithObject:@"class_name" forKey:@"key"];

is invalid because (a) NSMutableDictionary is a type; (b) you are creating a dictionary, not a mutable dictionary; (c) you are creating it every time, and overwriting the previous ones; (d) you are creating the dictionary with the constant values @"class_name" and keys @"key", which does not corresponds to the actual variables class_name and key.

To add the key-value pairs into 1 hash table, you should create the mutable dictionary at the beginning

NSMutableDictionary* dict = [NSMutableDictionary dictionary];

and then in the loop, use -setObject:forKey: to add it into the dictionary:

[dict setObject:class_name forKey:key];

To conclude, you should modify the code as

NSMutableDictionary* dict = [NSMutableDictionary dictionary];
for(NSString *s in mainarr) {
    NSArray *subarray = [s componentsSeparatedByString:@"="]; 

    // Get the elements of array into key and object string variables 
    NSString *key = [subarray objectAtIndex:0]; 
    NSLog(@"%@",key); 
    NSString *class_name= [subarray objectAtIndex:1]; 
    NSLog(@"%@",class_name); 

    //Putting the key and objects values into hashtable  
    [dict setObject:class_name forKey:key];
}    
return dict;

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