PHP中的通配符替换

Question

I have no experience using regular expressions in PHP, so I usually write some convoluted function using a series of str_replace(), substr(), strpos(), strstr() etc (you get the idea).

This time I want to do this correctly, I know I need to use a regex for this, but am confused as to what to use (ereg or preg), and how exactly the syntax should be.

NOTE: I am NOT parsing HTML, or XML, and sometimes I will be using delimiters other than (for example, | or ~ or [tag] or ::). I am looking for a generic way to do a wildcard replace in between two known delimiters using regex, I am not building an HTML or XML parser.

What I need is a regex that replaces this:

<sometag>everything in here</sometag>

with this:

<sometag>new contents</sometag>

I have read the documentation online for a bit, but I am confused, and am hoping one of you regex experts can pop in a simple solution. I suspect I will pass the values to a function, something like this:

$new_text = swapText ( "<sometag>", $the_new_text_to_go_into_the_dag );

function swapText ( $in_tag_with_brackets_to_update, $in_new_text ) {
 // define tags
 $starting_tag  = $in_tag_with_brackets_to_update;
 $ending_tag    = str_replace( "<", "</", $in_tag_with_brackets_to_update) );

 // not sure if this is the proper regex match string or not
 // and/or if any escaping needs to be done on the tags
 $find_string         = "{$starting_tag}.*{$ending_tag}";
 $replace_with_string = "{$starting_tag}{$in_new_text}{$ending_tag}";

 // after some regex, this function should return new version of <tag>data</tag>
}

Thanks.

Answer 1

@OP, there's no need to use complicated regex or a parser if your task is very simple. an example just using your normal substrings....

$mystr='<sometag>everything in here</sometag>';
$start=strpos($mystr,"<sometag>");
$end=strpos($mystr,"</sometag>");
print substr($mystr,0,$start+strlen("<sometag>") ) . "new value" . substr($mystr,$end);