pattern-matching

Excel Matching problem with logic expression

(I understand Excel is only borderline programming) I have a block of data that represents the steps in a process and the possible errors: ProcessStep Status FeesPaid OK FormRecvd OK RoleAssigned OK CheckedIn Not Checked In. ReadyToStart Not Ready for Start I want to find the first Status that is not "OK". I have a...

"Pattern matching" of algebraic type data constructors

Let's consider a data type with many constructors: data T = Alpha Int | Beta Int | Gamma Int Int | Delta Int I want to write a function to check if two values are produced with the same constructor: sameK (Alpha _) (Alpha _) = True sameK (Beta _) (Beta _) = True sameK (Gamma _ _) (Gamma _ _) = True sameK _ _ = False Maintaining sam...

PHP/Zend: How to remove all chars from a string and keep only numbers.

I want to keep only numbers and remove all characters from a variable. For example: input: +012-(34).56.(ASD)+:"{}|78*9 output: 0123456789 ...

Scala wont pattern match with java.lang.String and Case Class

Hello fellow Scala Programmers I have been working with Scala for some month now, however I have a problem with some properly basic stuff, I am hoping you will help my out with it. case class PersonClass(name: String, age: Int) object CaseTester { def main(args:Array[String]) { val string = "hej" string match { case e:String ...

Pattern Matching of Units of Measure in F#

This function: let convert (v: float<_>) = match v with | :? float<m> -> v / 0.1<m> | :? float<m/s> -> v / 0.2<m/s> | _ -> failwith "unknown" produces an error The type 'float<'u>' does not have any proper subtypes and cannot be used as the source of a type test or runtime coercion. Is there any way how to pattern match...

Numerical Pattern Matching

A project I'm researching requires some numerical pattern matching. My searches haven't turned up many relevant hits since most results tend to be around text pattern matching. The idea is we'll have certain wave patterns we'll need to be watching for and trying to match incoming data vs the wave database we will be building. Here is and...

Scala: type variance and pattern matching between two equal types

I was playing around the other day with making a class to handle some arithmetic operations (yes, I know numeric is coming out in 2.8) and found myself wondering how to simplify the following: def Foo[A]( _1:A, _2:A ) = (_1, _2) match{ case _1:Bar, _2:Bar => _1 + _2 case _1:Baff, _2:Baff => _1 push _2 case _, _ => None } s...

Lua pattern matching vs. regular expressions

Hello, I'm currently learning lua. regarding pattern-matching in lua I found the following sentence in the lua documentation on lua.org: Nevertheless, pattern matching in Lua is a powerful tool and includes some features that are difficult to match with standard POSIX implementations. As I'm familiar with posix regular expressions...

F# pattern matching when mixing DU's and other values

What would be the most effective way to express the following code? match cond.EvalBool() with | true -> match body.Eval() with | :? ControlFlowModifier as e -> match e with | Break(scope) -> e :> obj //Break is a DU element of ControlFlowModifier | _ -> next() //other members of CFM shoul...

How to verify if file is according to mask in PHP without reading filename from disk.

I have a list of file names(I already have the filelist let's say in a text file). I want to process this list in the following way: filenames of type /dirX/subdirX//.ext will be written in a new file all the other filenames will be written in a separate file. Is there any option to verify if a filename corresponds to a mask, without...

xslt broken: pattern does not match

I'm trying to query an xml file using the following xslt: <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:bpmn="http://dkm.fbk.eu/...

Matching a rotated bitmap to a collage image

Hi, My problem is that I have an image of a detailed street map. On this map, there can be a certain small image of a sign (such as a traffic light icon) rotated at any angle, maybe resized. I have this small image in a bitmap. Is there any algorithm or technique by which I can locate this bitmap if a copy of it exists, rotated and mayb...

How to detect identical part(s) inside string?

I try to break down the http://stackoverflow.com/questions/2711961/decoding-algorithm-wanted question into smaller questions. This is Part I. Question: two strings: s1 and s2 part of s1 is identical to part of s2 space is separator how to extract the identical part(s)? example 1: s1 = "12 November 2010 - 1 visitor" s2 = "6 July 201...

pattern matching and returning new object based on pattern

Say I've got some code like this match exp with | Addition(lhs,rhs,_) -> Addition(fix lhs,fix rhs) | Subtraction(lhs,rhs,_) -> Subtraction(fix lhs,fix rhs) is there any way that would allow me to do something like match exp with | Addition(lhs,rhs,_) | Subtraction(lhs,rhs,_) -> X(fix lhs,fix rhs) where X be based on the actual patt...

Strange pattern matching with functions instancing Show

So I'm writing a program which returns a procedure for some given arithmetic problem, so I wanted to instance a couple of functions to Show so that I can print the same expression I evaluate when I test. The trouble is that the given code matches (-) to the first line when it should fall to the second. {-# OPTIONS_GHC -XFlexibleInstance...

OCaml: Matching with any negative

Is there a way to get pattern matching to match my value with any negative number? It does not matter what the negative number is I just need to match with any negative. I have accomplished what I want with this simple code: let y = if(n < 0) then 0 else n in match y with 0 -> [] | _ -> [x] @ clone x (n - 1) But I want to e...

Apache URL rewrite query

Can anyone tell me how to do this? i'm stumped! I need a modified URL in this format this55-is-a-test-id-23.html But I need the 23 as a GET. I can't rely on searching for 'id' as this may occur elsewhere in the URL. Is there any way of searching for the last occurrence of id and passing that as a get using an Apache RewriteRule in .ht...

What algorithm would you use to code a parrot?

A parrot learns the most commonly uttered words and phrases in its vicinity so it can repeat them at inappropriate moments. So how would you create a software version? Assuming it has access to a microphone and can record sound at will, how would you code it without requiring infinite resources? The best I can imagine is to divide the s...

regex and javascript, some matches disappear !

Here is the code : > var reg = new RegExp(" hel.lo ", 'g'); > > var str = " helalo helblo helclo heldlo "; > > var mat = str.match(reg); > > alert(mat); It alerts "helalo, helclo", but i expect it to be "helalo, helblo, helclo, heldlo" . Only the half of them matches, I guess that's because of the space wich count only once. So I ...

Spotting similarities and patterns within a string - Python

Hi folks, this is the use case I'm trying to figure this out for. I have a list of spam subscriptions to a service and they are killing conversion rate and other usability studies. The emails inserted look like the following: [email protected] [email protected] [email protected] ro...