Question

我对正则表达式相当弱，这让我头疼，试图弄明白。我只是想从字符串中提取时间并修改时间的文本。我得到以下形式的字符串：

"Some text I don't care about | 2.3 seconds ago"
"Some text I don't care about | 5.2 minutes ago"
"Some text I don't care about | 7.0 hours ago"
"Some text I don't care about | 1.9 days ago"

我想将上面的字符串替换为表格中的字符串：

"2.3 secs"
"5.2 mins"
"7.0 hrs"
"1.9 days"

我知道在正则表达式中替换的基础知识，但删除我想要的文本前后的多个内容，同时用“小时”替换“小时”等等，超出了我的正则表达式技能水平。

任何帮助都将不胜感激。

感谢。

修改

在搞砸了我之后，我找到了使用多种不同功能的解决方案。我不是很喜欢它，但它确实有效。如果可能的话，我更喜欢单个preg_replace解决方案。这是我目前的丑陋的解决方案：

$testString = "This is text I don't care about | 7.3 seconds ago";
$testString = array_shift(array_reverse(explode('|', $testString)));
$pattern = array('/seconds/', '/minutes/', '/hours/', '/ago/');
$replace = array('secs', 'mins', 'hrs', '');
$testString = trim(preg_replace($pattern, $replace, $testString));

输出为：7.3 secs

Answer 1

如果你真的想在一行上搜索/替换，你可以这样做：

$time_map = array(
  'seconds' => 'secs',
  'minutes' => 'mins',
  'hours'   => 'hrs',
  'days'    => 'days',
);

$data = array(
    "Some text I don't care about | 2.3 seconds ago",
    "Some text I don't care about | 5.2 minutes ago",
    "Some text I don't care about | 7.0 hours ago",
    "Some text I don't care about | 1.9 days ago",
);

foreach ($data as $line) {
    $time_data = preg_replace_callback("/(.*|\s*)([0-9]+\.[0-9]+) (\w+) ago/",  function ($matches) use ($time_map) {return $matches[2] . " " . $time_map[$matches[3]];}, $line);
    print "$time_data\n";
}

产生：

2.3 secs
5.2 mins
7.0 hrs
1.9 days

Answer 2

preg_replace有一个可选的第4个参数，它是一个限制。限制是它可以替换的最大匹配数量。 Php preg_replace它是自动全局的，这意味着它将替换所有匹配项，除非您为该限制设置了正数。

http://php.net/manual/en/function.preg-replace.php

Answer 3

使用preg_match和str_replace函数的简单解决方案：

$testString = "This is text I don't care about | 7.3 seconds ago";
$timeUnitsmap = ["secs" => "seconds", "mins" => "minutes", "hrs" => "hours"];

preg_match("/\b[0-9.]+? \w+?\b/i", $testString, $matches);
$testString = str_replace(array_values($timeUnitsmap), array_keys($timeUnitsmap), $matches[0]);

print_r($testString);  // "7.3 secs"

或使用preg_replace_callback和array_search函数：

...
$testString = preg_replace_callback(["/.*?\b([0-9.]+? )(\w+?)\b.*/"], function($m) use($timeUnitsmap){
    return $m[1]. array_search($m[2], $timeUnitsmap);
}, $testString);

PHP preg_replace多个替换

3 个答案: