NSPredicate和正则表达式 [英] NSPredicate and Regex

问题描述

有人可以帮助我将Regex与NSPredicate一起使用吗?

Can someone please help me with using Regex with NSPredicate?

NSString *regex = @"(?:[A-Za-z0-9])";
NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
if ([pred evaluateWithObject:mystring])
{
  //do something
}

测试上面的mystring-qstring123似乎不起作用.我期望它进入if条件，因为它应该与正则表达式匹配.

testing the above wth mystring - qstring123 doesn't seem to work. I am expecting it to enter the if condition because it supposedly should match the regex.

此外，我需要一个用于字母数字的正则表达式，以允许使用逗号和空格.

Besides, I need a regex for alpha numberic allowing commas and spaces.

这行得通吗?

@"(?:[A-Za-z0-9])*(?:,[A-sa-z0-9)*(?:\s[A-sa-s0-9])"

请帮助.

推荐答案

根据我的实验，它尝试将正则表达式与整个字符串匹配，而在字符串内部不匹配.

From my experimentation, it tries to match the regex against the entire string, and won't match inside a string.

因此，正则表达式[a-zA-Z0-9]+有效，但[a-zA-Z0-9]无效.

Therefore, the regex [a-zA-Z0-9]+ works, but [a-zA-Z0-9] does not.

考虑到这一点，您可能需要重新处理逗号匹配谓词，或者使用功能更全的正则表达式解决方案，例如令人惊叹的 RegexKit和RegexKitLite .

With that in mind, you may want to rework your comma-matching predicate, or use a more full-featured regex solution, like the amazingly awesome RegexKit and RegexKitLite.

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