NSPredicate忽略空格 [英] NSPredicate that ignores whitespaces

问题描述

我需要使用NSPredicate来匹配两个字符串，不区分大小写，区分不区分大小写，和空白不区分大小写。

看起来像这样：

  [NSPredicate predicateWithFormat：@Key == [cdw]％@，userInputKey]; 
  

'w'修饰符是一个用来表达我想使用的修饰符。 p>

我不能修剪 userInputKey ，因为数据源Key值可能也有空格

例如，给定一个 userInputKey abc谓词应该匹配

 {abc，abc，a BC} 

等等。给定 userInputKey a BC，谓词也应该匹配上面集合中的所有值。

解决方案

如何定义这样的东西：

  +（NSPredicate *）myPredicateWithKey：（NSString *）userInputKey {
 return [NSPredicate predicateWithBlock：^ BOOL（NSString * calculatedString，NSDictionary * bindings） {
 //从两个字符串中删除所有空格
 NSString * strippedString = [[evaluateString componentsSeparatedByCharactersInSet：[NSCharacterSet whitespaceCharacterSet]] componentsJoinedByString：@]; 
 NSString * strippedKey = [[userInputKey componentsSeparatedByCharactersInSet：[NSCharacterSet whitespaceCharacterSet]] componentsJoinedByString：@]; 
 return [strippedString caseInsensitiveCompare：strippedKey] == NSOrderedSame; 
}]; 
} 
  

然后使用它：

  NSArray * testArray = [NSArray arrayWithObjects：@abc，@a bc，@ABC，@AB，@a B d @A bC，nil]; 
 NSArray * filteredArray = [testArray filteredArrayUsingPredicate：[MyClass myPredicateWithKey：@a B C]]; 
 NSLog（@filteredArray：％@，filteredArray）; 
  

结果是：

  2012-04-10 13：32：11.978 Untitled 2 [49613：707] filteredArray：（
 abc，
a bc，
ABC 
A bC
）
  

I need to use NSPredicate to match two strings, case-insensitive, diacritic insensitive, and whitespace-insensitive.

The predicate would look something like this:

[NSPredicate predicateWithFormat:@"Key ==[cdw] %@", userInputKey];

The 'w' modifier is an invented one to express what I'd like to use.

I can't just trim the userInputKey because the data-source "Key" values might have whitespaces in them too (they need those whitespaces, I can't just trim them beforehand).

For example, given a userInputKey "abc" the predicate should match all of

{"abc", "a b c", " a B    C   "}

and so on. Given a userInputKey"a B C" the predicate should also match all the values in the set above.

This can't be so hard to do, can it?

解决方案

How about defining something like this:

+ (NSPredicate *)myPredicateWithKey:(NSString *)userInputKey {
    return [NSPredicate predicateWithBlock:^BOOL(NSString *evaluatedString, NSDictionary *bindings) {
        // remove all whitespace from both strings
        NSString *strippedString=[[evaluatedString componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] componentsJoinedByString:@""];
        NSString *strippedKey=[[userInputKey componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] componentsJoinedByString:@""];
        return [strippedString caseInsensitiveCompare:strippedKey]==NSOrderedSame;
    }];
}

Then use it like this:

NSArray *testArray=[NSArray arrayWithObjects:@"abc", @"a bc", @"A B C", @"AB", @"a B d", @"A     bC", nil];
NSArray *filteredArray=[testArray filteredArrayUsingPredicate:[MyClass myPredicateWithKey:@"a B C"]];               
NSLog(@"filteredArray: %@", filteredArray);

The result is:

2012-04-10 13:32:11.978 Untitled 2[49613:707] filteredArray: (
    abc,
    "a bc",
    "A B C",
    "A     bC"
)

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