I want to extract two substrings from a predictably formatted string.
Each string is comprised of letters followed by numbers.
Inputs & Outputs:
MAU120=>MAUand120MAUL345=>MAULand345MAUW23=>MAUWand23
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2Would we ever have a number without letters, or letters without numbers?Levi Morrison– Levi Morrison2011-10-12 18:09:39 +00:00Commented Oct 12, 2011 at 18:09
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Does it always start with MAU and end with a number like your examples? It's more helpful if you can specify a general pattern rather than random examples.Herbert– Herbert2011-10-12 18:15:33 +00:00Commented Oct 12, 2011 at 18:15
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Consider this answer stackoverflow.com/questions/18031055/…ymakux– ymakux2016-12-23 13:53:22 +00:00Commented Dec 23, 2016 at 13:53
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4 Answers
$matches = array();
if ( preg_match('/^([A-Z]+)([0-9]+)$/i', 'MAUL345', $matches) ) {
echo $matches[1]; // MAUL
echo $matches[2]; // 345
}
If you require the MAU you can do:
/^(MAU[A-Z]*)([0-9]+)$/i
Removing i modifier at the end will make the regex case-sensitive.
3 Comments
Herbert
Also matches
mAuL345 and bob2.
webbiedave
OP never stated that
MAU was a requirement, nor case. I've edited my answer to show a way to require MAU and added info about the case modifier.Herbert
Sorry @webbie. I wasn't criticizing your approach. I was merely pointing out some matches that the OP didn't specify by example. The problem is that the OP didn't say much of anything concerning the desired pattern. Nevertheless, this is a much better answer than it was. +1 :-)
Try this regular expression:
/(\D*)(\d*)/
PHP code:
$matches = array();
var_dump( preg_match('/(\D*)(\d*)/', 'MAUL345', $matches) );
var_dump( $matches );
3 Comments
Levi Morrison
That looks dangerous. . . "?@#!123" now parses. . .
Levi Morrison
?@#!123 will be parsed as ?@#! and 123. That probably introduced characters that will correctly parse that are not intended by the OP. Hence, looks dangerous.
Code Jockey
The OP just says "the substring from string before first number occurs" (title) -- the examples specifically use letters, but the question itself does not exclude them...
Taken literally from your examples:
<?php
$tests = array('MAU120', 'MAUL345', 'MAUW23', 'bob2', '?@#!123', 'In the MAUX123 middle.');
header('Content-type: text/plain');
foreach($tests as $test)
{
preg_match('/(MAU[A-Z]?)(\d+)/', $test, $matches);
$str = isset($matches[1]) ? $matches[1] : '';
$num = isset($matches[2]) ? $matches[2] : '';
printf("\$str = %s\n\$num = %d\n\n", $str, $num);
}
?>
Produces:
$test = MAU120
$str = MAU
$num = 120
$test = MAUL345
$str = MAUL
$num = 345
$test = MAUW23
$str = MAUW
$num = 23
$test = bob2
$str =
$num = 0
$test = ?@#!123
$str =
$num = 0
$test = In the MAUX123 middle.
$str = MAUX
$num = 123
Comments
When you can guarantee that there will be one or more non-numbers and then one or more numbers, you can call upon sscanf() to parse the string.
The native function has multiple advantages over preg_match().
- It doesn't return the fullstring match.
- It will allow you to type cast substrings depending on the format placeholder you use.
- It can return its array or create reference variables -- depending on the number of parameters you feed it.
Code: (Demo)
$tests = [
'MAU120',
'MAUL345',
'MAUW23',
];
foreach ($tests as $test) {
sscanf($test, '%[^0-9]%d', $letters, $numbers);
var_export([$letters, $numbers]);
echo "\n";
}
Output: (notice that the numbers are cast as integer type)
array (
0 => 'MAU',
1 => 120,
)
array (
0 => 'MAUL',
1 => 345,
)
array (
0 => 'MAUW',
1 => 23,
)
If your numbers might start with zero(s) and you want to retain them, you can use %s instead of %d to capture the non-whitespaces substring. If you use %s, then the digits will be cast as a string instead of int-type.
Alternative syntax: (Demo)
foreach ($tests as $test) {
var_export(sscanf($test, '%[^0-9]%d'));
echo "\n";
}