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PHP: Find number of different letters in a string

Posted by: admin July 12, 2020 Leave a comment

Questions:

I want to find how many unique characters a string contains. Examples:

"66615888"    contains 4 digits (6 1 5 8).
"12333333345" contains 5 digits (1 2 3 4 5).
How to&Answers:
echo count( array_unique( str_split( '66615888')));

Demo

Docs:

  1. count() – Count the number of elements in an array
  2. array_unique() – Find the unique elements in an array
  3. str_split() – Split a string into an array

Answer:

count_chars gives you a map of char => frequency, which you can sum up with with array_sum:

$count = array_sum(count_chars($str));

Alternatively you can use the 3 mode for count_chars which will give you a string containing all unique characters:

$count = strlen(count_chars($str, 3));

Answer:

PHP has a function that counts characters.

$data = "foobar";
$uniqued = count_chars($data, 3);// return string(5) "abfor"
$count = strlen($uniqued);

Please see the documentation here.

Answer:

You can use the following script:

<?php
  $str1='66615888';
  $str2='12333333345';
  echo 'The number of unique characters in "'.$str1.'" is: '.strlen(count_chars($str1,3)).' ('.count_chars($str1,3).')'.'<br><br>';
  echo 'The number of unique characters in "'.$str2.'" is: '.strlen(count_chars($str2,3)).' ('.count_chars($str2,3).')'.'<br><br>';
?>

Output:

The number of unique characters in “66615888” is: 4 (1568)

The number of unique characters in “12333333345” is: 5 (12345)


Here PHP string function count_chars() in mode 3 produces an array having all the unique characters.

PHP string function strlen() produces total number of unique characters present.

Answer:

Here is another version that also works with multibyte strings:

echo count(array_keys(array_flip(preg_split('//u', $str, null, PREG_SPLIT_NO_EMPTY))));