Increment integer at end of string

Complex solutions for a really simple problem...

$str = 'Chicago-Illinos1';
echo $str++; //Chicago-Illinos2

If the string ends with a number, it will increment the number (eg: 'abc123'++ = 'abc124').

If the string ends with a letter, the letter will be incremeted (eg: '123abc'++ = '123abd')

$string = 'Chicago-Illinois1';
preg_match('/^([^\d]+)([\d]*?)$/', $string, $match);
$string = $match[1];
$number = $match[2] + 1;

$string .= $number;

Tested, works.

explode could do the job aswell

<?php
$str="Chicago-Illinos1"; //our original string

$temp=explode("Chicago-Illinos",$str); //making an array of it
$str="Chicago-Illinos".($temp[1]+1); //the text and the number+1
?>

I would use a regular expression to get the number at the end of a string (for Java it would be [0-9]+$), increase it (int number = Integer.parse(yourNumberAsString) + 1), and concatenate with Chicago-Illinos (the rest not matched by the regular expression used for finding the number).

You can use preg_match to accomplish this:

$name = 'Chicago-Illinos10';
preg_match('/(.*?)(\d+)$/', $name, $match);
$base = $match[1];
$num = $match[2]+1;
print $base.$num;

The following will output:

Chicago-Illinos11

However, if it's possible, I'd suggest placing another delimiting character between the text and number. For example, if you placed a pipe, you could simply do an explode and grab the second part of the array. It would be much simpler.

$name = 'Chicago-Illinos|1';
$parts = explode('|', $name);
print $parts[0].($parts[1]+1);

If string length is a concern (thus the misspelling of Illinois), you could switch to the state abbreviations. (i.e. Chicago-IL|1)

$str = 'Chicago-Illinos1';
echo ++$str;

http://php.net/manual/en/language.operators.increment.php

Without pre-isolating the numeric string suffix, there are two options to increment it.

1. ++$string or $string++ - unary operators allow the incrementation and decrementation of values

2. As of PHP8.3, str_increment() can be called with slightly more stable behavior, but the string itself must be entirely alphanumeric. Note that if you needed to increment an array of strings, having this new native function permits functional iterators (like array_map()) to call str_increment by its name alone.

Now for the bad news...

Both of these techniques will corrupt the left-neighboring character if the whole suffix number would ordinarily gain another digit. For instance, a9 would increment to b0 and z99 would become aa00.

If that wasn't enough to worry you, there is also the risk of incrementing a string value that resembles a float value. The string value 4567e4 would be incremented to the float-type value 45670001.0.

Read the manual: https://www.php.net/manual/en/language.operators.increment.php

Because those "convenient" techniques are rather unreliable, a better general-use approach would be to separate, increment, and replace the numeric suffix.

You can avoid declaring a temporary variable by calling preg_replace_callback(). I recommend this technique for directness and stability -- it will always return a string. Match the whole numeric suffix, increment it, then replace the original suffix with the incremented suffix. No side effects.

Code: (Demo)

$string = 'Chicago41Illinos9';

var_export(
    preg_replace_callback(
        '/\d+$/',
        fn($m) => ++$m[0],
        $string
    )
);
// Chicago41Illinos10

_{To edit a number anywhere in the string, just remove the $ (end of string anchor) from the pattern.}