pattern-matching

问题 I have a reference b/w image that contains a reference object (a coin for example). The object is marked by the user, that is the region of interest. Now I want to analyze other images and find the position and rotation of that object or similar objects. The object is arbitrarily placed under the camera, but is never scaled and the viewing angle is always 90 degrees. I have evaluated a commercial library that does exactly what I want: Euresys EasyFind Below you can find example images of the

问题 I'm trying to find all the data in ColumnX where the Data begins with a \ . Is like '\%' what I'm looking for? But the \ has to be at the beginning. 回答1: Your syntax would work in standard SQL, because \ is not a meta character in strings. But it very much depends on which DBMS and version you are actually using - and what your current settings are. In PostgreSQL POSIX-style escapes in strings used to be interpreted, so you would have to double \ to \\ to get an ordinary backslash. The SQL

问题 I need to test if any part of a column value is in a given string, instead of whether the string is part of a column value. For instance: This way, I can find if any of the rows in my table contains the string 'bricks' in column : SELECT column FROM table WHERE column ILIKE '%bricks%'; But what I'm looking for, is to find out if any part of the sentence " The ships hung in the sky in much the same way that bricks don’t " is in any of the rows. Something like: SELECT column FROM table WHERE

问题 Given the following: $ echo $BASH_VERSION 4.2.10(1)-release $ shopt | fgrep case nocaseglob off nocasematch off $ case A in [a-z]) echo TRUE;; esac TRUE I expect that the capital letter A should not match the lower-case character class of [a-z] , but it does. Why doesn't this match fail? 回答1: You can't reliably use the dash this way. If I don't use dashes, it works as expected: $ bash --version GNU bash, version 4.2.10(1)-release (x86_64-pc-linux-gnu) Copyright (C) 2011 Free Software

问题 Is there any difference between: foo is null and foo == null ? 回答1: Short version: For well-behaved types, there is no difference between foo is null and foo == null . Long version: When you write foo == null and an appropriate overload of operator == exists, then that's what is called. Otherwise, reference equality is used for reference types and value equality is used for value types. When you write foo is null for a reference type, this is compiled as if you wrote object.Equals(null, foo)

问题 In Swift, there's a common if let pattern used to unwrap optionals: if let value = optional { print("value is now unwrapped: \(value)") } I'm currently doing this kind of pattern matching, but with tuples in a switch case, where both params are optionals: //url is optional here switch (year, url) { case (1990...2015, let unwrappedUrl): print("Current year is \(year), go to: \(unwrappedUrl)") } However, this prints: "Current year is 2000, go to Optional(www.google.com)" Is there a way I can

问题 I am combining all my javascriupt into one neat file in order to lower http requests! Im stuck removing the comments /* comments */ and // comments . My level is by far below minification or parsing stuff. I know how to make macaroni strings. Anything more complex than that, you will not find in my computer or kitchen, SO: QUESTION meanwhile at combining it to one file, i want to remove all comments. What is the correct regex for this? <?php header('Content-type: text/javascript'); $offset =

问题 I'm trying to detect laughing words like "hahahaha" and "lolololol" in a string. Currently I'm using the following regex: ^((.*?)|)(\b[ha]|\b[lo])(.*?)$ However, this doesn't work for my purposes. It works , but it also matches words totally unrelated to laughter, such as 'kill', because it simply looks for any word that contains the letters l, o, h, a. How can I detect laughing words (like "hahaha" or "lololol") in a string? 回答1: try with this pattern: \b(?:a*(?:ha)+h?|(?:l+o+)+l+)\b or

问题 I am trying to calculate edit distances of a string against a collection to find the closest match. My current problem is that the collection is very large (about 25000 items), so I had to narrow down the set to just strings of similar lengths but that still would only narrow it down to a few thousand strings and this still is very slow. Is there a datastructure that allows for a quick lookup of similar strings or is there another way I could address this problem? 回答1: Sounds like a BK-tree

问题 I am trying to match a simple domain: example.com But all combinations of it. How would I do this to cover: https://example.com http://www.example.com etc. 回答1: ^https?://([\w\d]+\.)?example\.com$ using code: var result = /^https?:\/\/([a-zA-Z\d-]+\.){0,}example\.com$/.test('https://example.com'); // result is either true of false I improved it to match like "http://a.b.example.com" 回答2: You can probably use to just match the domain name part of a URL: /^(?:http(?:s)?:\/\/)?(?:[^\.]+\.)