如果是，则使用正则表达式-如何编写条件

Question

Trying to capture name= and value= US or NONE (if selected="selected" not included). Given the following (part of a larger $page):

$page = '
<select name="country" ><option value="NONE">Select One</option>    
<option value="AE">UNITED ARAB EMIRATES</option>
<option value="GB">UNITED KINGDOM</option>
<option value="US" selected="selected">UNITED STATES</option>
<option value="UY">URUGUAY</option>
<option value="UZ">UZBEKISTAN</option>
<option value="ZW">ZIMBABWE</option></select>';

Edit 1 This pattern won't pick up NONE if none of the options are selected.

$pattern = '/select name="([a-zA-Z]*)"\s?>[\w\W]*value="([A-Z]{2,4})"(selected="selected">)?/'

So, I'm looking for a pattern that will.

Answer 1

The syntax for the if, then, else regex in php is:

(if 'selected=' found) then find pattern     | else find this pattern
  (if condition)        then regex           |   else regex
(?(?=.*selected=)value="([A-Z]+)"\s+selected=|value="(NONE)">)

The .* is necessary for the condition to be true.

Answer 2

Does it have to be one regex ?

I would recommend splitting it up this way:

• match the element
  
• tryMatch with the "selected" attribute
  
• proceed according to results - I'm not sure what the logic is as don't quite undestand from your description when you want which value. But either way it should be easy to get either value or name attributes.

The benefit of this approach is that you are working on a part of the html code and it's far less error prone.

EDIT:

BTW: how do you know it never evaluates to true ? It seems to work as intended (ie matching 'select' or 'select name="country") here
http://www.pagecolumn.com/tool/pregtest.htm

(you need to escape the quotes (?(?=selected=\\"selected\\")select|select name=\\"([a-zA-Z]*)\\") to use it there)

EDIT2

I still won't be able to help you with if then else, but based on your explanation I can suggest this:

<select name="([^"]*)".*?(?!</select>)<option value="[^"]*" selected="selected"|<select name="([^"]*)"\s*>\s*<option value="([^"]*)">

• so, tryMatch selected, if it fails match just the first option