How to use strstr() php - php

Question

I want to cut text in array but I have no idea to cut this
I try strstr() but it not true.
I try
$ff='';
while($row = mysqli_fetch_array($result,MYSQLI_ASSOC)){
$ff .= $row['fav'] . ",";
}
if( strpos( $ff, "_" )) {
$text = strstr($ff, '_');
echo $text;
}
$ff ='A_0089,A_5677,B_4387,A_B_5566,'
I want output show
0089,5677,4387,B_5566,

Answer 1

Here is one example, using substr() with strpos():
$ff='A_0089,A_5677,B_4387,A_B_5566';
$items = explode(',', $ff);
foreach($items as $item) {
echo substr($item, strpos($item, '_')) . "\n";
}
The above code returns:
_0089
_5677
_4387
_B_5566
You're better off not building a string, but building an array. The way you build the string you have a dangling comma, which you do not want.
$ff = array();
while($row = mysqli_fetch_array($result,MYSQLI_ASSOC)){
$ff[] = $row['fav'];
}
foreach($ff as $item) {
echo substr($item, strpos($item, '_')) . "\n";
}
Based on your desire to keep the commas and create a string:
$ff='A_0089,A_5677,B_4387,A_B_5566,';
$items = explode(',', $ff);
foreach($items as $item) {
$new[] = substr($item, strpos($item, '_'));
}
$newFF = implode(',', $new);
echo $newFF;
returns:
_0089,_5677,_4387,_B_5566,

Answer 2

Probably this is what you are looking for
<?php
function test_alter(&$item1)
{
$pattern = '/^[A-Z]{1}[_]{1}/';
$item1 =preg_replace($pattern,"",$item1);
}
$ff="A_0089,A_5677,B_4387,A_B_5566,";
$nff=explode(",",$ff);
array_walk($nff, 'test_alter');
echo implode(",",$nff);
?>