Check if whole string contains same character - php

Question

I want to check if a string contains a character repeated zero or more times, for example:
If my string is aaaaaa, bbbb, c or ***** it must return true.
If it contains aaab, cd, or **%*** it must return false.
In other words, if the string has 2 or more unique characters, it must return false.
How to go about this in PHP?
PS: Is there a way to do it without RegEx?

Answer 1

You could split on every character then count the array for unique values.
if(count(array_count_values(str_split('abaaaa'))) == 1) {
echo 'True';
} else {
echo 'false';
}
Demo: https://eval.in/760293

Answer 2

count(array_unique(explode('', string)) == 1) ? true : false;

Answer 3

You can use a regular expression with a back-reference:
if (preg_match('/^(.)\1*$/', $string)) {
echo "Same characters";
}
Or a simple loop:
$same = true;
$firstchar = $string[0];
for ($i = 1; $i < strlen($string); $i++) {
if ($string[$i] != $firstchar) {
$same = false;
break;
}
}

Answer 4

For the fun of it:
<?php
function str2Dec($string) {
$hexstr = unpack('H*', $string);
$hex = array_shift($hexstr);
return hexdec($hex);
}
function isBoring($string) {
return str2Dec($string) % str2Dec(substr($string, 0, 1)) === 0;
}
$string1 = 'tttttt';
$string2 = 'ttattt';
var_dump(isBoring($string1)); // => true
var_dump(isBoring($string2)); // => false
Obviously this works only in small strings because once it gets big enough, the INT will overflow and the mod will not produce the correct value. So, don't use this :) - posting it just to show a different idea from the usual ones.

Answer 5

strlen(str_replace($string[0], '', $string)) ? false : true;

Answer 6

You can check that the number of unique characters is greater than 1. This will perform well even if the input string is empty: (Demo)
$string = 'aaaba';
var_export(
strlen(count_chars($string, 3)) < 2 // false
);
Alternatively, you can trim the string by its first character, but this will generate warnings/notices if the input string has no length. (Demo)
$string = 'aaaba';
var_export(
!strlen(trim($string, $string[0])) // false
);
p.s. Yes, you could use !strlen(trim($string, #$string[0])) to prevent warnings/notices caused by a zero-length string, but I avoid error suppression like the plague because it generally gives code a bad smell.

Answer 7

Regex: ^(.)\1{1,}
^: Starting of string
(.): Match and capture single characted.
\1{1,}: using captured character one or more than once.
For this you can use regex
OR:
PHP code demo
$string="bbbb";
if($length=strlen($string))
{
substr_count($string,$string[0]);
if($length==substr_count($string,$string[0]))
{
echo "Do something";
}
}