过滤字符串中不是数字的字符

NSCharacterSet *setToRemove =

[[ NSCharacterSet characterSetWithCharactersInString:@"0123456789"]

invertedSet ];

NSString *strPhone = @"";

strPhone  = [[@"qwe123" componentsSeparatedByCharactersInSet:setToRemove] componentsJoinedByString:@""];

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strPhone筛选后就是123