Question

I’ve bought RegexBuddy, given it a try and unless I am matching on something static, and simple – I just can’t get regex!

What I am trying to do is from the following line of text; I would like to extract tidal information into an associative array.

High Tide: 2.0m on Mon at 08.54pm and 2.4m on Tue at 09.18am

And end up with the following array:

[0] =
  'Day' => 'Mon',
  'Time' => '8.54pm',
  'Height' => '2.0m',
  'Tide' => 'High'

[1] =
  'Day' => 'Tue',
  'Time' => '09.18am',
  'Height' => '2.4m',
  'Tide' => 'High'

The concept I am struggling most with is the fact that there are multiple matches that I wish to extract (e.g. 2.0m and 2.4m). I’ve managed to match on 2.0m, and 2.4m, but how do I determine which one is which? (First High tide vs second high tide).

Any hints?

Answer 1

$string = "High Tide: 2.0m on Mon at 08.54pm and 2.4m on Tue at 09.18am";

preg_match_all("~((High|Low) Tide:)? (\d.\dm) on (\w{3}) at (.{7})~", $string, $matches, PREG_SET_ORDER);

var_dump($matches);

outputs

array
  0 => 
    array
      0 => string 'High Tide: 2.0m on Mon at 08.54pm' (length=33)
      1 => string 'High Tide:' (length=10)
      2 => string 'High' (length=4)
      3 => string '2.0m' (length=4)
      4 => string 'Mon' (length=3)
      5 => string '08.54pm' (length=7)
  1 => 
    array
      0 => string ' 2.4m on Tue at 09.18am' (length=23)
      1 => string '' (length=0)
      2 => string '' (length=0)
      3 => string '2.4m' (length=4)
      4 => string 'Tue' (length=3)
      5 => string '09.18am' (length=7)

i probably got the thing about the low tide wrong so here is some code without the tide

$string = "High Tide: 2.0m on Mon at 08.54pm and 2.4m on Tue at 09.18am";

preg_match_all("~(\d.\dm) on (\w{3}) at (.{7})~", $string, $matches, PREG_SET_ORDER);

var_dump($matches);

outputs:

array
  0 => 
    array
      0 => string '2.0m on Mon at 08.54pm' (length=22)
      1 => string '2.0m' (length=4)
      2 => string 'Mon' (length=3)
      3 => string '08.54pm' (length=7)
  1 => 
    array
      0 => string '2.4m on Tue at 09.18am' (length=22)
      1 => string '2.4m' (length=4)
      2 => string 'Tue' (length=3)
      3 => string '09.18am' (length=7)