#define NUMBERS @"0123456789"
[[NSCharacterSet characterSetWithCharactersInString:NUMBERS]invertedSet];；
NSString * filtered = [[string componentsSeparatedByCharactersInSet:cs]componentsJoinedByString:@""];
BOOL ISNumber = [string isEqualToString:filtered];
原文：http://www.cnblogs.com/isItOk/p/5215574.html