How to loop over a string's characterss? - php

Question

Basically, I have an array of strings, and I want to check if each character in each string is in a predefined $source string. Here is how I think it should be done:
$source = "abcdef";
foreach($array as $key => $value) {
foreach(char in $value) {
if(char is not in source)
unset($array[$key]); //remove the value from array
}
}
If this is a correct logic, how to implement the foreach and the if parts?

Answer 1

You could try this:
$array = array('1' => 'cab', '2' => 'bad', '3' => 'zoo');
$source = "abcdef";
foreach($array as $key => $value) {
$split = str_split($value);
foreach($split as $char){
$pos = strrpos($source, $char);
if ($pos === false) {
unset($array[$key]);
break;
}
}
}
Result:
array(2) {
[1]=>
string(3) "cab"
[2]=>
string(3) "bad"
}
DEMO: http://codepad.org/fU99Gdtd

Answer 2

Try this code:
$source = "abcdef";
foreach($array as $key => $value) {
$ichr = strlen($value) - 1;
// traverses each character in string
for($i=0; $i<$ichr; $i++) {
if(stristr($value{$i}) === false) {
unset($array[$key]);
break;
}
}
}

Answer 3

$array = array("abc","defg","asd","ade","de","fe");
$source = "abcde";
foreach ($array as $key => $string){
for($i=0;$i<strlen($string);$i++){
if(strpos($source, $string[$i])===false){
unset($array[$key]);
}
}
}
Now the array looks like
array(3) {
[0]=>
string(3) "abc"
[3]=>
string(3) "ade"
[4]=>
string(2) "de"
}

Answer 4

As I understand you want to filter ( remove ) the characters, that are not defined in the $source variable. By Mark Baker comments, this is what you need:
$source = str_split ( "abdef" ); //defined characters
$target = str_split ( "atyutyu" ); //string to be filtered
$result = array_intersect ( $target, $source );
echo implode( $result ); // output will be only "a"
And full example:
$source = str_split ( "abdef" );
$txts = array ( "alfa", "bravo", "charlie", "delta" );
function filter ( $toBeChecked, $against )
{
$target = str_split ( $toBeChecked );
return implode ( array_intersect ( $target, $against ) );
}
foreach ( $txts as &$value )
{
$value = filter ( $value, $source );
}
foreach ( $txts as $value )
{
echo $value . ", ";
}
//output afa, ba, ae, ae

Answer 5

$array = array(
'abacab',
'baccarat',
'bejazzle',
'barcode',
'zyx',
);
$source = "abcde";
$sourceArray = str_split($source);
foreach($array as $value) {
$matches = array_intersect($sourceArray, str_split($value));
echo $value;
if (count($matches) == 0) {
echo ' contains none of the characters ', $source, PHP_EOL;
} elseif (count($matches) == count($sourceArray)) {
echo ' contains all of the characters ', $source, PHP_EOL;
} else {
echo ' contains ', count($matches), ' of the characters ', $source, ' (', implode($matches), ')', PHP_EOL;
}
}
gives
abacab contains 3 of the characters abcde (abc)
baccarat contains 3 of the characters abcde (abc)
bejazzle contains 3 of the characters abcde (abe)
barcode contains all of the characters abcde
zyx contains none of the characters abcde