PHPda Teskari Chiziq Muammosi

Teskari chiziq PHPning maxsus belgisidir. Bu shuni anglatadiki, qator ichida, agar biz xohlasak, chiziq o'zini anglatishi uchun, biz uni ikki marta takrorlashimiz kerak:

php<?php
  $str = '\\ \\\\ \\\\\\'; // aslida qator '\ \\ \\\'
?>

Teskari chiziq shuningdek muntazam ifodalarning ham maxsus belgisidir. Bu shuni anglatadiki, muntazam ifoda ichida, chiziq o'zini anglatishi uchun, uni to'rt marta yozishimiz kerak:

php<?php
  echo preg_replace('#\\\\#', '!', '\\ \\\\ \\\\\\'); // chiqadi '! ! !!'
?>

Keling endi shunday muntazam ifoda yozaylik, unda qidiruv shabloni quyidagicha bo'ladi: teskari chiziq bir yoki bir necha marta. Bunday holda biz + operatorini guruhlamasdan oldingi 4 belgi uchun yozamiz:

php<?php
  echo preg_replace('#\\\\+#', '!', '\\ \\\\ \\\\\\'); // chiqadi '! ! !'
?>

php<?php
  $str = 'a\\b c\\d e\\f';
?>

php<?php
  $str = 'a\\b c\\\\d e\\\\\\f';
?>