PHP wont recognise double line feed

Question

I am running a RST to php conversion and am using preg_match.

this is the rst i am trying to identify:

An example of the **Horizon Mapping** dialog box is shown below. A 
summary of the main features is given below. 

.. figure:: horizon_mapping_dialog_horizons_tab.png 

   **Horizon Mapping** dialog box, *Horizons* tab 

Some of the input values to the **Horizon Mapping** job can be changed 
during a Workflow using the internal programming language, IPL. For 
details, refer to the *IPL User Guide*.

and I am using this regex:

$match = preg_match("/.. figure:: (.*?)(\n{2}[ ]{3}.*\n)/s", $text, &$result);

however it is returning as false. here is a link of the expression working on regex http://regex101.com/r/oB3fW7.

Why the `s` flag? You do have a newline at the end of your input? How do you check the result? It seems like `\R` should work, can you add more info? — Robin, Jun 17 '14 at 14:42
I used the s flag because I read on a similar problem that the s flag did something with a double line feed he $match variable is a boolean value and will return true if a match is found yes there is a new line after the text I have updated the question with more rst — tht13, Jun 18 '14 at 06:05

score 2 · Answer 1 · answered Jun 17 '14 at 13:50

2

Are you sure that the line break is \n, is doubt, use \R:

$match = preg_match("/.. figure:: (.*?)(\R{2}[ ]{3}.*\R)/s", $text, &$result);

\R stands for either \n, \r and \r\n

answered Jun 17 '14 at 13:50

Toto

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it still wont find it, if i remove a line and only search for one line feed it works however the second messes it up – tht13 Jun 17 '14 at 13:55

score 0 · Answer 2 · edited May 23 '17 at 12:21

My instinct would be to do some troubleshooting around the s flag as well as the $result variable passed by reference. To achieve the same without any interference from dots and the return variable, can you please try this regex:

..[ ]figure::[ ]([^\r\n]*)(?:\n|\r\n){2}[ ]{3}[^\r\n]*\R

In code, please try exactly like this:

$regex = "~..[ ]figure::[ ]([^\r\n]*)(?:\n|\r\n){2}[ ]{3}[^\r\n]*\R~";
if(preg_match($regex,$text,$m)) echo "Success! </br>";

Finally:

If this does not working, you might have a weird Unicode line break that php is not catching. To debug, for each character of your string, iterate through all the string's characters

Iterate: foreach(str_split($text) as $c) {
Print the character: echo $c . " value = "
Print the value from this function: . _uniord($c) . "<br />"; }

The regex you provided didnt work, however I tried the uniord and it gave me a weird output that the line feeds were spaces, and the 3 spaces before the ** on the second line were not even there, is there a site where I could upload my files you you to see what I mean? $result is also returning an emtpy array — tht13, Jun 18 '14 at 06:25

PHP wont recognise double line feed

2 Answers2