PHP正则表达式用于特定的文本模式

Question

On my website I've inserted the year a project was created in the body and swapping that out with "six years ago" (or however long it was).

So in my content I have:

We've been in business since 1998 and produced this packaging design [2011] years ago.

I'm trying to use regex to put 2011 into a variable to later search and replace, and can't figure it out. There's only going to be one instance per page. I'm fine with searching and replacing, it's just regex I've never been able to get my head around.

To address comments below - the year is variable, that's why I'm wanting to use regex.

example

$bodycontent = <p>We've been in business since 1998 
and produced this logo design [2002] years ago.</p>

or

$bodycontent = <p>We've been in business since 1998 
and produced this website design [2016] years ago.</p>

So I put the year held in braces into a variable with regex as $then, subtract that from the current year to make $age (which is converted into a word by another function)

$bodycontent = str_replace("[".$then."]",$age,$bodycontent)

I've tried

preg_match("[\d{4}]",$bodycontent,$found); 

but it returns the first date — not the one in braces.

Answer 1

Use function preg_replace_callback() :

$bodycontent = preg_replace_callback('~\[(\d{4})\]~', function($match) {
    return (date('Y') - $match[1]) . " ago";
}, $bodycontent);

demo

Answer 2

If this was my project, I'd probably go with a preg_replace_callback() call leveraging a lookup array of words, and a fallback replacement when the bracketed date was "out of range".

*It is important that you are pluralizing year when appropriate.
*The second ] in my pattern doesn't need escaping, but you may add it if you you feel it improves readability.
*I am also matching years ago so that the replacement text makes sense in all cases; you may like to remove this trailing text in the original input text.

Code: ( Demo )

$bodycontent = "<p>We've been in business since 1998 and produced this logo design [1995] years ago.</p>\n";
$bodycontent .= "<p>We've been in business since 1998 and produced this website design [2018] years ago.</p>\n";
$bodycontent .= "<p>We've been in business since 1998 and produced this website design [2017] years ago.</p>\n";
$bodycontent .= "<p>We've been in business since 1998 and produced this website design [2016] years ago.</p>";

$lookup=['less than a','one','two','three','four','five','six','seven','eight','nine',
         'ten','eleven','twelve','thirteen','fourteen','fifteen','sixteen','seventeen','eighteen','nineteen'
];  // extend as needed

$bodycontent = preg_replace_callback('/\[(\d{4})] years ago/', function($m)use($lookup){
    $diff=date('Y')-$m[1];
    if(isset($lookup[$diff])){
        return $lookup[$diff].' year'.($diff>1?'s':'').' ago';
    }else{
        return "in {$m[1]}";  // out of lookup range, use backup text
    }
}, $bodycontent);

echo $bodycontent;

Output:

<p>We've been in business since 1998 and produced this logo design in 1995.</p>
<p>We've been in business since 1998 and produced this website design less than a year ago.</p>
<p>We've been in business since 1998 and produced this website design one year ago.</p>
<p>We've been in business since 1998 and produced this website design two years ago.</p>

Answer 3

Assuming this format [2002] years , as an alternative to you might use this regex:

\\[(\\d{4})\\] years

Explanation

\[      # Match [
(       # Capturing group
  \d{4} # Match 4 digits
)       # Close capturing group
\]      # Match ]
 years  # Match `whitespace`years

Then you could use preg_match to match the year in group 1, calculate the difference in years and perform formatting for singular or plural.

For example:

$bodycontent = "<p>We've been in business since 1998 and produced this logo design [2002] years ago.</p>";

preg_match('/\[(\d{4})\] years/', $bodycontent, $matches);
$years = date('Y') - $matches[1];
$result = sprintf("%s year%s",
    $years,
    $years === 1 ? "": "s"
    );
$bodycontent =  str_replace($matches[0], $result, $bodycontent);

Demo php output