问题描述
好的，所以这是计划。我从中获取数据的XML允许电话号码字段中的非数字文本（用于描述或联系人姓名等）。我试图只提取数字并用它们调用tel：URL来发起呼叫。这里有什么不工作：
OK So here's the plan. The XML I'm getting data from allows non-numeric text in phone number fields (for descriptions or contact names, etc). I am trying to extract only the numbers and call the tel: URL with them to initiate a call. Here's whats NOT working:
NSCharacterSet *charset = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
NSString *number = @"(555) 555-5555 Office";
NSString *strippedNumber = [number stringByTrimmingCharactersInSet:charset];
NSString *phoneURL = [NSString stringWithFormat:@"tel:%@", strippedNumber];
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:phoneURL]];
如果有任何明显的拼写错误，它们只是错别字。 ：）
if there are any obvious typos, they're just typos. :)
推荐答案
您正在使用trim方法，这意味着它只查看字符串的外边缘。你可能得到类似的东西：555）555-555作为电话号码，对吗？
You're using a trim method, which means that it's only looking at the outer edges of the string. You're probably getting something like: "555) 555-555" as the phone number, correct?
我不知道NS（Mutable）String方法沿着replaceOccurrencesOfCharactersInSet：（NSCharacterSet *）set，我承认，这可能真的很棒。
I'm not aware of an NS(Mutable)String method along the lines of "replaceOccurrencesOfCharactersInSet:(NSCharacterSet *)set", and I admit, that'd probably be really nice to have.
作为我，我可能只需使用正则表达式。如果您使用，那么您可以轻松地执行以下操作：
Being me, I'd probably just use a regex. If you use RegexKitLite, then you can easily do:
#import "RegexKitLite.h"
NSString * number = @"(555) 555-555 Office";
NSString * strippedNumber = [number stringByReplacingOccurrencesOfRegex:@"[^0-9]" withString:@""];
这可能有点矫枉过正，但它会完全符合您的要求。
It might be a bit overkill, but it will do exactly what you're looking for.
FYI：[^ 0-9]表示任何不是0,1,2,3,4,5,6,7,8或9的字符 。
FYI: "[^0-9]" means "any character that's not 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9".
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