考虑以下字符串和正则表达式:
$string= "just/RB convinced/VBN closing/VBG 10dma/NN need/VBN see/VB";
echo preg_replace("/(w+)/(JJ|RB|VB)/", "not$1/$2", $tweet);
我想把"not"连接到每个以/JJ、/RB或/VB结尾的单词上。但是,正则表达式也捕获/VB:/VBN和/VBG的变体。输出为
notjust/RB notconvinced/VBN notclosing/VBG 10dma/NN notneed/VBN notsee/VB
然而,预期输出是:
notjust/RB convinced/VBN closing/VBG 10dma/NN need/VBN notsee/VB
如何阻止正则表达式获取这些变体?
使用b
字边界:
$string= "just/RB convinced/VBN closing/VBG 10dma/NN need/VBN see/VB";
echo preg_replace("/(w+)/(JJ|RB|VB)b/", "not$1/$2", $tweet);
b
仅在字母数字字符与非字母数字字符或字符串的开始/结束之间匹配。