来自NSString的子串

Question

我正在使用NSString,我想得到一个包含我的字符串的前20个字符的子字符串.我怎样才能做到这一点？

Answer 1

你可以用substringToIndex.

NSString *mystring = @"This is a test message having more than 20 characters";
NSString *newString = [mystring substringToIndex:20];
NSLog(@"%@", newString);

Answer 2

NSString *str = @"123456789012345678901234";
NSString *subStr = [str substringWithRange:NSMakeRange(0, 20)];