pattern-matching - w3toppers.com

Replace HTML codes with equivalent characters in Java [duplicate]

Also, is there any way to optimize this regex? Yes, don’t use regex for this task, use Apache StringEscapeUtils from Apache commons lang: import org.apache.commons.lang.StringEscapeUtils; … String withCharacters = StringEscapeUtils.unescapeHtml(yourString); JavaDoc says: Unescapes a string containing entity escapes to a string containing the actual Unicode characters corresponding to the escapes. Supports HTML 4.0 entities. For … Read more

How do I match based on a dynamic variable?

You can use Match guards. let string = match current % 2 { even if even == numbers[0] => “even”, odd if odd == numbers[1] => “odd”, _ => unreachable!() };

Find matching strings between two vectors in R

How is this case class match pattern working?

When doing pattern matching, the Scala compiler will interpret o1 c1 o2 the same as c1(o1, o2). That’s why :: works inside pattern matches too.

Can I match a data constructor wildcard in Haskell?

Nope. But you can write this: data Foo = X { name :: String, age :: Int } | A { name :: String } | B { name :: String } | C { name :: String } | D { name :: String } and then have name :: Foo -> String. You … Read more

How to pattern match large Scala case classes?

I don’t know if this is appropriate, but you can also build an object just to match that field, or that set of fields (untested code): object WideLoadActorRef { def unapply(wl: WideLoad): Option[ActorRef] = { Some(wl.d) } } someVal match { case WideLoadActorRef(d) => d ! someMessage } or even object WideLoadBnD { def unapplySeq(wl: … Read more

The argument types of an anonymous function must be fully known. (SLS 8.5)

{ case X(x) => … } is a partial function, but the compiler still doesn’t know what your input type is, except that it’s a supertype of X. Normally this isn’t a problem because if you’re writing an anonymous function, the type is known from the context. But here is how you can provide the … Read more

XML schema restriction pattern for not allowing specific string

OK, the OP has persuaded me that while the other question mentioned has an overlapping topic, the fact that the forbidden string is forbidden at all locations, not just as a prefix, complicates things enough to require a separate answer, at least for the XSD 1.0 case. (I started to add this answer as an … Read more

how to recognize similar words with difference in spelling

The Double Metaphone algorithm, published in 2000, is a new and improved version of the Soundex algorithm that was patented in 1918. The article has links to Double Metaphone implementations in many languages.

notepad++ Inverse Regex replace (all but string)

^((?!hello).)*$ works in Notepad++ 6. I wonder if it’s better than this: ^(?!.*hello).*$