pattern-matching

Is there a way to match inequalities in Python ≥ 3.10?

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You can use guards: match a: case _ if a < 42: print(‘Less’) case _ if a == 42: print(‘The answer’) case _ if a > 42: print(‘Greater’) Another option, without guards, using pure pattern matching: match [a < 42, a == 42]: case [True, False]: print(‘Less’) case [_, True]: print(‘The answer’) case [False, False]: … Read more

How to combine multiple regex into single one in python?

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You need to compile all your regex functions. Check this example: import re re1 = r’\d+\.\d*[L][-]\d*\s[A-Z]*[/]\d*’ re2 = ‘\d*[/]\d*[A-Z]*\d*\s[A-Z]*\d*[A-Z]*’ re3 = ‘[A-Z]*\d+[/]\d+[A-Z]\d+’ re4 = ‘\d+[/]\d+[A-Z]*\d+\s\d+[A-Z]\s[A-Z]*’ sentences = [string1, string2, string3, string4] for sentence in sentences: generic_re = re.compile(“(%s|%s|%s|%s)” % (re1, re2, re3, re4)).findall(sentence)

Finding matches between high quality and low quality, pixelated images – is it possible ? How?

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I really see no reason to use any external libraries for this, I’ve done this sort of thing many times and the following algorithm works quite well. I’ll assume that if you’re comparing two images that they have the same dimensions, but you can just resize one if they don’t. badness := 0.0 For x, … Read more

Regular Expression to match 3 or more Consecutive Sequential Characters and Consecutive Identical Characters

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I don’t think you can (easily) use regex for the first case. The second case is easy though: Pattern pattern = Pattern.compile(“([a-z\\d])\\1\\1”, Pattern.CASE_INSENSITIVE); Since \\1 represents part matched by group 1 this will match any sequence of three identical characters that are either within the range a-z or are digits (\d). Update To be clear, … Read more

Expression of type T cannot be handled by a pattern of type X

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As explained by Neal Gafter from Microsoft: The reason it doesn’t work is that there is no conversion (explicit or implicit) defined from T to KeepalivePacket. Pattern matching requires such a conversion to exist, as it is defined in terms of the cast operator, which requires a conversion exist. The language specification and compiler agree … Read more

Expected String, found &str when matching an optional string

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The way you usually convert a &str to a String is to_owned, e.g. “me”.to_owned() However, you can’t do pattern matching on a String. You could expect a success, get a &str from the String then pattern match on that: fn player_starts() -> bool { println!(“Who will start (me/you)”); loop { let input = readline::readline(“>”); match … Read more

Scala: Ignore case class field for equals/hascode?

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Only parameters in the first parameter section are considered for equality and hashing. scala> case class Foo(a: Int)(b: Int) defined class Foo scala> Foo(0)(0) == Foo(0)(1) res0: Boolean = true scala> Seq(0, 1).map(Foo(0)(_).hashCode) res1: Seq[Int] = List(-1669410282, -1669410282) UPDATE To expose b as a field: scala> case class Foo(a: Int)(val b: Int) defined class Foo … Read more