Home PHP C# C++ Android Java Javascript Python IOS SQL HTML Categories

In pattern matching, can I use the matched pattern as is?

If I understand your question correctly, you want to use the heading itself on ???'s place, this can be done using the @ pattern:

case first :: rest => first match {
      case head @ Heading(_,_) =>
buildPairsAcc(rest, acc, head)
      case Paragraph(_) // ... other cases

Note that this can be used on everything that'll pattern match, including lists:

case lst @ head::tail => // do stuff
with lst head and tail

Categories : Scala

Related to : In pattern matching, can I use the matched pattern as is?
Pattern synonyms lead to unexhaustive pattern matching
It is not implemented yet, see #8779. I'm not an expect here, but I know that exhaustiveness checks are hard to implement in a lot of cases, like GADT or guards. Probably it is problematic for pattern synonyms too.

Categories : Haskell
Remove everything else after a matched pattern
You can use capturing group and backreference. For example, in Javascript: "this is one nasty string nobody likes".replace(/(nasty string).*$/, '$1') // => "this is one nasty string" Alternatively, you can use positive lookbehind assertion if you regular expression engine support it. >>> # Python >>> import re >>> re.sub('(?<=nasty string).*$', '', "this is on

Categories : Regex
how to use actual file name matched by pattern in gulp-template
The glob pattern needs to be expanded into an array of actual filepaths. This is usually handled for you by gulp.src. You can use globby to expand the pattern like this: var gulp = require('gulp'); var template = require('gulp-template'); var globby = require('globby'); // npm install --save-dev globby var js = globby.sync(['js/**/*.js']); gulp.task('default', function() { return gulp.src(

Categories : Javascript
String Pattern Matching Check in c#
You can use Regex, grouping your patterns: using System; using System.Text.RegularExpressions; class Program { static void Main() { // First we see the input string. string input = "/content/alternate-1.aspx"; // Here we call Regex.Match. Match match = Regex.Match(input, @"content/([A-Za-z0-9-]+).aspx$", RegexOptions.IgnoreCase); // H

Categories : C#
parse using pattern matching in shell
You can use BASH regex: s='abc12c20m' if [[ "$s" =~ ^(abc)([0-9]+)c([0-9]+)m$ ]]; then var1=${BASH_REMATCH[1]} var2=${BASH_REMATCH[2]} var3=${BASH_REMATCH[3]} fi echo "$var1 - $var2 - $var3" abc - 12 - 20

Categories : Shell
Recently Add
Using sbt to build command line application
Remapping columns from a schemaRDD
How to use play-plugins-mailer with Play 2.3 and Scala 2.11?
Akka scala Event bus with different classifiers depending on the subscriber
Scala: Create a new list where each element is the elemnt of old list repeated with different suffix
Convert Scala Wrapper$MapWrapper to a Java Map
Timing MLlib algorithms when executed in Scala interactive shell
how to use play.api.mvc.Security class to check user is authenticated or not?
Why does this lambda function can't work with `_` in Scala?
using spark to read specific columns data from hbase
Scala limit function parameters possible types
head :: tail pattern matching for strings
What is the easiest and most efficient way to make a min heap in Scala?
Removing mutable collections and making it look more scala style
Reverse list of n elements
scalac: Error: object CharRef in intelliJ 14
Scala - trouble with type inference in lambda expression
Exception on spark test
How can I emulate Haskell's typeclasses in Scala?
Slick: CRUD extension: How to encapsulate implicit mapping:BaseColumnType[T]
Can't find Traverse for sequencing Seq[ValidationNel[String, MyCaseClass]] => ValidationNel[String, Seq[MyCaseClass]]
Tail recursion: internal "loop" function or default values for accumulators
Scala - Add element:MyType to Array = option[MyType] expected
Scala, Composing Function with two values
Using dependent type to generate compile error
How to match all words in a sentence with scala combinators?
Parser Alternative Operator | Fails
ScalaTest assertion mismatch due to Physical Address
Scala implicit parameter and japanese smiley 'foldLeft'
Is it possible to user reduceByKey((x, y, z) => ...)?
© Copyright 2017 Publishing Limited. All rights reserved.