检查 NSString 是否只是字母 [英] Check if NSString is only letters

问题描述

确保 NSString 仅包含字母 a-z 和 A-Z 的最佳方法是什么.

What's the best way to make sure an NSString contains only the letters a-z and A-Z.

我已经尝试了以下代码，但由于某种原因它不起作用:

I've tried the following code but it's not working for some reason:

NSString *myegex = @"[A-Za-z]";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", myregex];
if (![emailTest evaluateWithObject:self.initials.text])  {
     // print error
     return;
}

推荐答案

您可以通过创建自己的 NSCharacterSet 然后使用 rangeOfCharacterFromSet 对照该集合检查字符串来以更简单的方式完成此操作:

You can do it in a simpler way by creating your own NSCharacterSet then checking the string against that set with rangeOfCharacterFromSet:

//Create character set
NSCharacterSet *validChars = [NSCharacterSet characterSetWithCharactersInString:@"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"];

//Invert the set
validChars = [validChars invertedSet];

//Check against that
NSRange  range = [myString rangeOfCharacterFromSet:validChars];
if (NSNotFound != range.location) {

 //invalid chars found

}

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