substringFromIndex：从Index开始截取到最后

substringToIndex：从最前头一直截取到Index

substringFromIndex 和 substringToIndex用法，有需要的朋友可以参考下。

NSString *testsubstringToorFromIndex = @"test1234";

NSString *fromIndexstring = [testsubstringToorFromIndex substringFromIndex:2];

NSString *toIndexstring = [testsubstringToorFromIndex substringToIndex:2];

    NSLog(@"subtringfromindex is %@",fromIndexstring);

    NSLog(@"subtringToindex is %@",toIndexstring);

输出结果

2014-11-29 06:23:59.634 sdktest[587:11024] subtringfromindex is st1234

2014-11-29 06:23:59.634 sdktest[587:11024] subtringToindex is te