<?php # As well as preg_match and preg_match_all, we have ...

$line = "404 SN1 6QL 17 4 80 2 3";
$stations = file("railstats.xyz");
print ("We have read ".count($stations). " records\n");

# Regular expression - the bits I DON'T want returned to me ;-)

$gotten = preg_split("/\s+/",$line); # Typically the right thing.
var_dump($gotten); # Much more descriptibe than ..
print_r($gotten); # Dump variable content

$gotten = preg_split("/\s*/",$line); # NOT what you mean. Splits every character.
print_r($gotten); # Dump variable content

# Preg_match is against a STRING and returns part of the string (if you give it a $gotten)
# Preg_grep is against an ARRAY and returns complete array members and not parts of them.

$bigchurch = preg_grep("/Abbey/",$stations); # Filter, returning only matching array members
print_r($bigchurch);

# Match and replace all in one go!

$info = "Travel by train from Melksham to Westbury and on to Salisbury.\n";
$rv1 = preg_replace('/bury/','flower',$info); # All occurrences
print ($rv1);

$rv1 = preg_replace('/bury/','flower',$info,1); # Tell it how many
print ($rv1);

$rv1 = preg_replace('/bury/','flower',$info,-1,$tellme); # Tell me how many
print ("$tellme changes - becomes $rv1");

$rv1 = preg_replace('/bury/','flower',$info);
print ($rv1);

$rv1 = preg_replace('/.bury/','.flower',$info); # input is RE, output is just a string
print ($rv1); # so replaces "any char" with a .

# If I want to use part of my input string in my output, capture and use \\1 etc

$rv1 = preg_replace('/(.b)ury/','flower$1',$info); # Using part of matched input within output
print ($rv1);

# Match, compute using the matched string to generate the output

function compass($got) {
        $rotate = array('North' => 'West', 'West' => 'South', 'South' => 'East',
                        'East' => 'North');
        $result = $rotate[$got[1]];
        return $result;
}

$rv1 = preg_replace_callback('/(North|South|East|West)/',"compass",$info);
print ($rv1);

/* ----------------------------------------- Sample output

munchkin:re grahamellis$ php ex2.php
We have read 2537 records
array(8) {
  [0]=>
  string(3) "404"
  [1]=>
  string(3) "SN1"
  [2]=>
  string(3) "6QL"
  [3]=>
  string(2) "17"
  [4]=>
  string(1) "4"
  [5]=>
  string(2) "80"
  [6]=>
  string(1) "2"
  [7]=>
  string(1) "3"
}
Array
(
    [0] => 404
    [1] => SN1
    [2] => 6QL
    [3] => 17
    [4] => 4
    [5] => 80
    [6] => 2
    [7] => 3
)
Array
(
    [0] =>
    [1] => 4
    [2] => 0
    [3] => 4
    [4] =>
    [5] => S
    [6] => N
    [7] => 1
    [8] =>
    [9] => 6
    [10] => Q
    [11] => L
    [12] =>
    [13] => 1
    [14] => 7
    [15] =>
    [16] => 4
    [17] =>
    [18] => 8
    [19] => 0
    [20] =>
    [21] => 2
    [22] =>
    [23] => 3
    [24] =>
)
Array
(
    [8] => 1562 SAA AL1 2DN TL 144065 51.7447360734 -0.3425692916 St.Albans Abbey 174769 187112 207646 222482 217520 177470

    [237] => 3235 FIT BS34 7JW ST 610786 51.504939615 -2.5624372568 Filton Abbey Wood 377552 401325 410630 457611 536958 598032

    [626] => 6210 TNA DN39 6XF TA 108188 53.6539707522 -0.3234938147 Thornton Abbey 656 767 807 762 1102 1056

    [1988] => 5131 ABW SE2 9RH TQ 472791 51.4907705898 0.1203255703 Abbey Wood 2201541 2089975 2804493 3096498 3029176 2882868

)
Travel by train from Melksham to Westflower and on to Salisflower.
Travel by train from Melksham to Westflower and on to Salisbury.
2 changes - becomes Travel by train from Melksham to Westflower and on to Salisflower.
Travel by train from Melksham to Westflower and on to Salisflower.
Travel by train from Melksham to Wes.flower and on to Sali.flower.
Travel by train from Melksham to Wesflowertb and on to Saliflowersb.
Travel by train from Melksham to Southbury and on to Salisbury.
munchkin:re grahamellis$

---------------------------------------------------- */

?>