How can I get the last position of letters in a string formed by letters and numbers in php

Question

I am trying to make an automatic counter to get the last id of my database. I keep rows with an alphanumeric id:

AR1, AR2, AR3, TER17, KAKAP126...

it is varchar in database so I cannot make a +1. So I want to detect the end of the chars (letters) and delete them from the id, add +1 and concat the number to the letters part.

I tried this:

$s = $rowAtt['id']; (ie: TUR99)
echo $s;
echo "<br>";

for ($i = 1; $i <= strlen($s); $i++){
   $char = $a[$i-1];
   if (is_numeric($char)) {
      echo $char . ' is a number<br>';
   } else {
      echo $char . ' is a letter<br>';
   }
}

But It says always "is a letter"...

What can I do for that?

I don't want the last character, just the last not number of the string — Biribu, May 22 '14 at 17:19
it's not the last character - replace square brackets with curly ones to get " is a number" — Luis Masuelli, May 22 '14 at 17:19
I see, but it is the same I already have. I think I need to check each char with the first and the last number of letters. But I don't know how to do it — Biribu, May 22 '14 at 17:21
Your question title and content are different then what you are asking for in the comments. Please update the question and title to more clearly present what you actually want. — Josh Mein, May 22 '14 at 17:22
in your code you say strlen($s) but you refer as $a[$i - 1]; $a is not a defined var in your code — Luis Masuelli, May 22 '14 at 17:23
Possible duplicate of: http://stackoverflow.com/questions/12589519/how-do-i-grab-last-number-in-a-string-in-php — Josh Mein, May 22 '14 at 17:23
check since you're indexing the variable $a instead of variable $s — Luis Masuelli, May 22 '14 at 17:24

mts7 · Answer 1 · 2014-05-22T17:30:41.527

2

Here is something you could try.

function getLastLetter($str) {
    $str = preg_replace('/[^a-zA-Z]/', '', $str);
    return substr($str, -1);
}

function getLastLetterPosition($str) {
    $str = preg_replace('/[^a-zA-Z]/', '', $str);
    return strlen($str) - 1;
}

edited May 22 '14 at 17:30

answered May 22 '14 at 17:23

mts7

583
4
12

Ahh yours is simpler than mine. +1 – skrilled May 22 '14 at 17:23
I like this. Is it possible to get the possition instead of the last character? this way I'd just have to use substring after that... – Biribu May 22 '14 at 17:27
1

Sure, just grab the length of the new string and subtract 1. – mts7 May 22 '14 at 17:30

score 2 · Accepted Answer · answered May 22 '14 at 17:28

2

To get both the character and the numeric part separately:

  $testString="AAAK12";

  $chars = preg_split("/[0-9]+/", $testString);
  $nums = preg_split("/[a-zA-Z]+/", $testString);

  echo "Chars are " . $chars[0] . "\n";
  echo "Nums are " . $nums[1] . "\n";

Result:

Chars are AAAK
Nums are 12

answered May 22 '14 at 17:28

ebo

2,717
1
27
22

This is the cleanest solution. Thanks – Biribu May 22 '14 at 17:37

score 1 · Answer 3 · answered May 22 '14 at 17:20

Simple function that will return the last character, what you do with it is up to you:

function getLastChar($string)
{
  $newString = strrev($string);
  for($i=0;$i<=strlen($string);$i++)
  {
    if(!is_numeric($newString[$i])) return $newString[$i];
  }
  return false;
}

echo getLastChar('askdjwu12312');

result: u

score 1 · Answer 4 · answered May 22 '14 at 17:22

1

list($characters,$digits) = sscanf('%[A-Z]%d', $myString);
$lastCharacter = substr($characters, -1);

answered May 22 '14 at 17:22

Mark Baker

209,507
32
346
385

Manuel Ro · Answer 5 · 2014-05-22T18:05:50.053

1

Use string length as index:

A string in PHP can also behave as an array of chars. Therefore we can access each one of them via a simple syntax like: $string[n]. Everything else is a matter of using the string length as the index to retrieve the last letter.

This can be translated in code as follows:

$myString = 'Hello World';
$lastLetter = $myString[strlen($myString)-1];

Regards, M

edited May 22 '14 at 18:05

answered May 22 '14 at 17:27

Manuel Ro

206
3
10

score 0 · Answer 6 · answered May 22 '14 at 17:18

0

The php manual on substr says just use substr($foo, -1). Did you try that?

answered May 22 '14 at 17:18

MueR

977
7
13

1

I don't want the last character, just the last not number of the string – Biribu May 22 '14 at 17:19

How can I get the last position of letters in a string formed by letters and numbers in php

6 Answers6