Objective-C - 如何从字符串中删除字符？ [英] Objective-C - How To Remove Characters From a String?

问题描述

我有一个UILabel，它有一个格式化的字符串（格式为货币），所以有一个美元符号，$ 21.34。

在核心数据实体中，属性的类型是double，我使用NSDecimalNumber来保存到数据库中。

  self.purchase.name = self.nameTextField.text; 
 NSString * string = self.amountLabel.text 
 NSDecimalNumber * newAmount = [[NSDecimalNumber alloc] initWithString：string]; 
 NSLog（@％@，string）; //这个返回NaN，因为美元符号我想
 
 NSManagedObjectContext * context = self.purchase.managedObjectContext; 
 
 NSError * error = nil; 
 if（！[context save：& error]）
 {
 NSLog（@Unresolved error％@，％@，error，[error userInfo]）; 
 abort（）; 
 
 
 
 
 
 $ b无论如何，我需要这个不是NaN，所以我的想法是去除美元符号，但我不知道该怎么做，或者有更好的方法来实现我的目标。  
 
解决方案
 
  NSString * clearedString = [costString stringByTrimmingCharactersInSet：[NSCharacterSet symbolCharacterSet]]; 
  
比上面的更强大（我想它也会处理逗号） / p> 
I have a UILabel that has a formatted String (formatted for currency), so there is a dollar sign, $21.34. 

In the core data entity the attribute is of a type double, I am using an NSDecimalNumber to save to the database.
    self.purchase.name = self.nameTextField.text;
    NSString *string = self.amountLabel.text
    NSDecimalNumber *newAmount = [[NSDecimalNumber alloc] initWithString:string];
    NSLog(@"%@", string); // THIS RETURNS NaN, because of dollar sign i think

    NSManagedObjectContext *context = self.purchase.managedObjectContext;

    NSError *error = nil;
    if (![context save:&error]) 
    {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }
Anyway, I need this to not be NaN, so my thinking is to remove the dollar sign, but i do not know how to do that, or perhaps there is a better way to accomplish my goal.
解决方案
    NSString* cleanedString = [costString stringByTrimmingCharactersInSet: [NSCharacterSet symbolCharacterSet]];
Is a lot more robust than the one above (and I think it will handle commas, too)

                        
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