test - Regex para unir fracciones descuidadas/números mixtos

regex perl online

Question

Tengo una serie de texto que contiene números mixtos (es decir, una parte completa y una parte fraccionaria). El problema es que el texto está lleno de descuido codificado por el ser humano:

1. Toda la parte puede o no existir (ej: "10")
2. La parte fraccional puede o no existir (ej: "1/3")
3. Las dos partes pueden estar separadas por espacios y / o guiones (por ejemplo, "10 1/3", "10-1 / 3", "10 - 1/3").
4. La fracción misma puede o no tener espacios entre el número y la barra oblicua (por ejemplo, "1/3", "1/3", "1/3").
5. Puede haber otro texto después de la fracción que debe ignorarse

Necesito una expresión regular que pueda analizar estos elementos para poder crear un número adecuado a partir de este lío.

Answer 1

Aquí hay una expresión regular que manejará todos los datos que puedo arrojar sobre ella:

(/d++(?! */))? *-? *(?:(/d+) */ *(/d+))?.*$

Esto colocará los dígitos en los siguientes grupos:

1. La parte completa del número mixto, si existe
2. El numerador, si sale una fracción
3. El denominador, si existe una fracción

Además, aquí está la explicación de RegexBuddy para los elementos (que me ayudó enormemente al construirlo):

Match the regular expression below and capture its match into backreference number 1 «(/d++(?! */))?»
   Between zero and one times, as many times as possible, giving back as needed (greedy) «?»
   Match a single digit 0..9 «/d++»
      Between one and unlimited times, as many times as possible, without giving back (possessive) «++»
   Assert that it is impossible to match the regex below starting at this position (negative lookahead) «(?! */)»
      Match the character “ ” literally « *»
         Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
      Match the character “/” literally «/»
Match the character “ ” literally « *»
   Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
Match the character “-” literally «-?»
   Between zero and one times, as many times as possible, giving back as needed (greedy) «?»
Match the character “ ” literally « *»
   Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
Match the regular expression below «(?:(/d+) */ *(/d+))?»
   Between zero and one times, as many times as possible, giving back as needed (greedy) «?»
   Match the regular expression below and capture its match into backreference number 2 «(/d+)»
      Match a single digit 0..9 «/d+»
         Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
   Match the character “ ” literally « *»
      Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
   Match the character “/” literally «/»
   Match the character “ ” literally « *»
      Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
   Match the regular expression below and capture its match into backreference number 3 «(/d+)»
      Match a single digit 0..9 «/d+»
         Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
Match any single character that is not a line break character «.*»
   Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
Assert position at the end of the string (or before the line break at the end of the string, if any) «$»

Answer 2

Creo que puede ser más fácil abordar los diferentes casos (mezcla completa, solo fracción, solo número) de forma separada. Por ejemplo:

sub parse_mixed {
  my($mixed) = @_;

  if($mixed =~ /^ *(/d+)[- ]+(/d+) *// *(/d)+(/D.*)?$/) {
    return $1+$2/$3;
  } elsif($mixed =~ /^ *(/d+) *// *(/d+)(/D.*)?$/) {
    return $1/$2;
  } elsif($mixed =~ /^ *(/d+)(/D.*)?$/) {
    return $1;
  }
}

print parse_mixed("10"), "/n";
print parse_mixed("1/3"), "/n";
print parse_mixed("1 / 3"), "/n";
print parse_mixed("10 1/3"), "/n";
print parse_mixed("10-1/3"), "/n";
print parse_mixed("10 - 1/3"), "/n";

Answer 3

Si está usando Perl 5.10 , así es como lo escribiría.

m{ ^ /s* # skip leading spaces (?''whole'' /d++ (?! /s*[//] ) # there should not be a slash immediately following a whole number ) /s* (?: # the rest should fail or succeed as a group -? # ignore possible neg sign /s* (?''numerator'' /d+ ) /s* [//] /s* (?''denominator'' /d+ ) )? }x

Luego puede acceder a los valores de la variable %+ esta manera:

$+{whole};
$+{numerator};
$+{denominator};