NSString类中提供了这样三个方法用于获取子字符串:
– substringFromIndex:
– substringWithRange:
– substringToIndex:
它们该怎么使用呢?见下面代码即可知道。
NSString *str = @"12345";
// NSString *subString0 = [str
substringFromIndex:-1]; //会放生越界错误
NSString *subString1 = [str substringFromIndex:0];
//@"12345"
NSString *subString2 = [str substringFromIndex:1];
//@"2345"
NSString *subString3 = [str substringFromIndex:4];
//@"5"
NSString *subString4 = [str substringFromIndex:5];
//@""
// NSString *subString5 = [str substringFromIndex:6];
//会放生越界错误
// NSString *subString10 = [str substringToIndex:-1];
//会放生越界错误
NSString *subString11 = [str substringToIndex:0];
//@"“
NSString *subString12 = [str substringToIndex:1];
//@"1”
NSString *subString13 = [str substringToIndex:4];
//@"1234“
NSString *subString14 = [str substringToIndex:5];
//@"12345”
// NSString *subString15 = [str substringToIndex:6];
//会放生越界错误
NSRange range1 = NSMakeRange(-1, 5);
NSRange range2 = NSMakeRange(0, 6);
NSRange range3 = NSMakeRange(0, 5);
NSRange range4 = NSMakeRange(1, 4);
NSRange range5 = NSMakeRange(0, 0);
NSRange range6 = NSMakeRange(4, 1);
//NSString *subString31 = [str substringWithRange:range1]; //会放生越界错误
//NSString *subString32 = [str substringWithRange:range2]; //会放生越界错误
NSString *subString33 = [str substringWithRange:range3];
//@"12345“
NSString *subString34 = [str substringWithRange:range4];
//@"2345”
NSString *subString35 = [str substringWithRange:range5];
//@"”
NSString *subString36 = [str substringWithRange:range6];
//@"5”