if ([keyName rangeOfString:@"_"].location==NSNotFound){
return keyName;
}
else{
NSLog(@"不存在某一字符");
}
iOS判断字符串中含某一个字符if ([keyName rangeOfString:@"_"].location==NSNotFound) return keyName;
原文：http://blog.csdn.net/darongzi1314/article/details/44459353