语法突出显示，使用不区分大小写的语法

Question

I am trying to write a search and syntax highlighter. Let's presume we have a basic query, that is querying for countries based on a keyword, for example uni.

Right now, I am using Sphinx, to fetch the results that match with this keyword from a database, and I am using case-insensitive search. The results that sphinx return are the following:

Tanzania, United Republic of
United Arab Emirates
United Kingdom
United States
Igaunija
Estados unidos Mexicanos

I now want to highlight the search keyword from these strings, by wrapping the keyword in a <span>.

To achieve this, I was trying to do the following:

$search='uni';
foreach($keyword as $text) { // $keyword is an array, containg each found result one by one
  $text=str_replace($search, "<span>".$search."</span>", $text);
}

Whit this code, only Iguanija, and Estados unidos Mexicanos gets highlighted, because in every other case the keyword starts with an uppercase letter. If I change the str_replace to a str_ireplace, every search keyword get's highlighted, but in the first few entries, the uppercase U gets replaced with a lowercase u, so from United Kingdom, I get united Kingdom. How could I highlight the search keyword, and maintain the case of the characters in the result?

My desired result would be something like this:

Tanzania, <span>Uni</span>ted Republic of
<span>Uni</span>ted Arab Emirates
<span>Uni</span>ted Kingdom
<span>Uni</span>ted States
Iga<span>uni</span>ja
Estados <span>uni</span>dos Mexicanos

Answer 1

You can use a regular expression which will allow you to preserve the case of the source string.

<?php

$unis = <<< UNIS
Tanzania, United Republic of
United Arab Emirates
United Kingdom
United States
Igaunija
Estados unidos Mexicanos
UNIS;

var_dump(preg_replace('/(uni)/i','<span>$1</span>',$unis));

Output

string(190) "Tanzania, <span>Uni</span>ted Republic of
<span>Uni</span>ted Arab Emirates <span>Uni</span>ted Kingdom
<span>Uni</span>ted States Iga<span>uni</span>ja Estados
<span>uni</span>dos Mexicanos"