php 开发环境显示所有错误

<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);

preg_replace  preg_replace_callback 函数用法

<?php
// http://php.net/manual/en/function.preg-replace.php
// mixed preg_replace(mixed $pattern, mixed $replacement, mixed $subject [, int $limit = -1 [, int &$count ]] )

$string = "April 15, 2003";
$pattern = '/(\w+) (\d+), (\d+)/';
$replacement = '${1} 1st, $3';

echo preg_replace($pattern, $replacement, $string).PHP_EOL;

echo preg_replace_callback($pattern, function($matches) {
    // $matches[0] "April 15, 2003"
    return "$matches[1] 1st, $matches[3]";
}, $string).PHP_EOL;

unset($pattern, $replacement);

$string = 'The quick brown fox jumps over the lazy dog.';
$patterns = [
    0 => '/quick/',
    1 => '/brown/',
    2 => '/fox/'
];
$replacements = [
    0 => 'slow',
    1 => 'black',
    2 => 'bear'
];
echo preg_replace($patterns, $replacements, $string).PHP_EOL;

[mzh@iz2ze5rptd09gfzl0jpc3gz string]$ php replace.php
April 1st, 2003
April 1st, 2003
The slow black bear jumps over the lazy dog.