LocalTime.parse Since you only have a time use the LocalTime class. No need to define a formatting pattern in your case. String str = “12:22:10”; LocalTime time = LocalTime.parse(str); See that code run live at IdeOne.com. See Oracle Tutorial for more info.
[EDIT 2019] This answer is not meant to be a catch-all, works for everything solution it was intended to provide a simple alternative to the python based version and it ended up having more features than the original. It answered the basic question in a bash-only way and then was modified multiple times by myself … Read more
All of the other answers have missed how hard it is to do this properly. You can do a first cut approach at this which is accurate to a certain extent, but until you take into account IEEE rounding modes (et al), you will never have the right answer. I’ve written naive implementations before with … Read more
The simple answer is “Yes”. In the abstract, you don’t need lexers at all. You could simply write a grammer that used individual characters as tokens (and in fact that’s exactly what SGLR parsers do, but that’s a story for another day). You need lexers because parsers built using characters as primitive elements aren’t as … Read more
To check if a grammar is LL(1), one option is to construct the LL(1) parsing table and check for any conflicts. These conflicts can be FIRST/FIRST conflicts, where two different productions would have to be predicted for a nonterminal/terminal pair. FIRST/FOLLOW conflicts, where two different productions are predicted, one representing that some production should be … Read more
DateTimeFormatter dtf = DateTimeFormatter.ofPattern(“uuuu-MM-dd H:mm:ss”); With this change your program outputs: 2019-05-03T07:05:03 A single format pattern letter H will match hour of day in either 1 or two digits. That is, it will accept 7, 07, 13, etc. Two HH on the other hand requires two digits like 07 or 13, so 7 alone cannot … Read more
What you missed is whitespace. I threw in a couple bonus improvements. import scala.util.parsing.combinator._ object CSV extends RegexParsers { override protected val whiteSpace = “””[ \t]”””.r def COMMA = “,” def DQUOTE = “\”” def DQUOTE2 = “\”\”” ^^ { case _ => “\”” } def CR = “\r” def LF = “\n” def CRLF … Read more
Add Another “}” at end of your code you missed one 2.There is another error in your code if((value = “true”)) is not a proper way to check string equality and has syntax error it should be if(value.equals(“true”))
In most cases, you want to parse more than one hex byte at once. In those cases, use the hex crate. parse this into an integer You want to use from_str_radix. It’s implemented on the integer types. use std::i64; fn main() { let z = i64::from_str_radix(“1f”, 16); println!(“{:?}”, z); } If your strings actually have … Read more
A tokenizer breaks a stream of text into tokens, usually by looking for whitespace (tabs, spaces, new lines). A lexer is basically a tokenizer, but it usually attaches extra context to the tokens — this token is a number, that token is a string literal, this other token is an equality operator. A parser takes … Read more