I really like this trick. I do not know of any existing way to do this, and I don’t foresee any problem with it — which doesn’t mean much, though. I can’t think of any way to create a Not. As for adding it to the standard library… perhaps. But I think it’s a bit … Read more
As of the ides of March 2012, this works in 2.10+: def doMatch(seq: Seq[Int]): Unit = seq match { case last +: Seq() => println(“Final element.”) case head +: tail => println(“Recursing…”); doMatch(tail) } //> doMatch: (seq: Seq[Int])Unit doMatch(List(1, 2)) //> Recursing… //| Final element. More generally, two different head/tail and init/last decomposition objects mirroring … Read more
This is really simple, the String object has an endsWith method. From your question it seems like you want either /, , or . as the delimiter set. So: String str = “This.is.a.great.place.to.work.”; if (str.endsWith(“.work.”) || str.endsWith(“/work/”) || str.endsWith(“,work,”)) // … You can also do this with the matches method and a fairly simple regex: … Read more
Of course, there are many ways to test a string for only numeric characters. Two possible methods are: bool is_digits(const std::string &str) { return str.find_first_not_of(“0123456789”) == std::string::npos; } or bool is_digits(const std::string &str) { return std::all_of(str.begin(), str.end(), ::isdigit); // C++11 }
… like ‘[[]%’ You use [ ] to surround a special character (or range). See the section “Using Wildcard Characters As Literals” in SQL Server LIKE Note: You don’t need to escape the closing bracket…
It works this way by design, but admittedly it can be a bit confusing at first glance. This feature allows you to destructure maps using pattern matching, without having to specify all keys. For example: iex> %{b: value} = %{a: 1, b: 2, c: 3} %{a: 1, b: 2, c: 3} iex> value 2 Consequently, … Read more
Be aware that this language feature is only available in C# 6 and later. It’s effectively the equivalent of: x == null ? null : x.y == null ? null : x.y.z In other words, it’s a “safe” way to do x.y.z, where any of the properties along the way might be null. Also related … Read more
\Q means “start of literal text” (i.e. regex “open quote”) \E means “end of literal text” (i.e. regex “close quote”) Calling the Pattern.quote() method wraps the string in \Q…\E, which turns the text is into a regex literal. For example, Pattern.quote(“.*”) would match a dot and then an asterisk: System.out.println(“foo”.matches(“.*”)); // true System.out.println(“foo”.matches(Pattern.quote(“.*”))); // false … Read more
Try this glob pattern: myProject/src/**/!(*.js|*.map|*.src)
Parameterized active patterns to the rescue! let (|Prefix|_|) (p:string) (s:string) = if s.StartsWith(p) then Some(s.Substring(p.Length)) else None match “Hello world” with | Prefix “The” rest -> printfn “Started with ‘The’, rest is %s” rest | Prefix “Hello” rest -> printfn “Started with ‘Hello’, rest is %s” rest | _ -> printfn “neither”