仅使用RegEx替换段落中单词的首次出现

Question

I have two paragraphs. I want to replace ONLY first occurrence of a specific word ' acetaminophen ' by ' {yootooltip :: It is a widely used over-the-counter analgesic (pain reliever) and antipyretic (fever reducer). Excessive use of paracetamol can damage multiple organs, especially the liver and kidney.}acetaminophen{/yootooltip} '

The paragraph is: Percocet is a painkiller which is partly made from oxycodone and partly made from acetaminophen . It will usually be prescribed for a patient who is suffering from acute severe pain. Because it has oxycodone in it, this substance can create an addiction and is also a dangerous prescription drug to abuse. It is illegal to either sell or use Percocet that has not been prescribed by a licensed professional. In 2008, drugs like Percocet (which have both oxycodone and acetaminophen as their main ingredients) were the prescription drugs most sold in all of Ontario. The records also show that the rates of death by oxycodone (this includes brand name like Percocet) doubled. That is why it is imperative that the people who are addicted go to an Ontario drug rehab center. Most of the drug rehabs can take care of Percocet addiction.

I am trying to write a regular expression for this. I have tried \\bacetaminophen\\b But it is replacing both occurrences. Any help would be appreciated. Thanks

Answer 1

Use the optional $limit parameter in PHP's preg_replace function http://us2.php.net/manual/en/function.preg-replace.php

$text = preg_replace('/acetaminophen/i', 'da-da daa', $text, 1);

will replace only the first occurance.

Answer 2

对于您正在使用的工具 ，只需使用以下命令：

(.*?)\bacetaminophen\b