Find character in string

This calls for a specialized function. Well, I quickly developed the following:

function nthstrpos($haystack, $needle, $nth) {
    $count = 0;
    $pos = -1;
    do {
        $pos = strpos($haystack, $needle, $pos + 1);
        $count++;
    } while ($pos !== false && $count < $nth);
    return $pos;
}

The function nthstrpos() gets three parameters:

For example, the command nthstrpos('banana', 'a', 2) will return the second occurrence of the letter a in the text banana .

If the text to be searched is not found or the number of the requested occurrence exceeds the total number of occurrences, the return will be false .

Run on Ideone

use strpos link

You can loop through the $ offset from where the function should start fetching

Something like this

<?php

$texto = "um texto muito longo cheio de letras, numeros, fatos, historias, aventuras e altas confusões na sessao da tarde.";
$achar = "a";
$posicoes = array();
$offset = 0;

while ( ($pos = strpos($texto, $achar, $offset)) !== false) {

    $posicoes[] = $pos;
    $offset = $pos+1;
}

print_r($posicoes);

Update

If you want you can also use regular expressions, which in my opinion is much more elegant:

<?php

$re = "/a/";
$str = "um texto muito longo cheio de letras, numeros, fatos, historias, aventuras e altas confusões na sessao da tarde.";

preg_match_all($re, $str, $resultados, PREG_OFFSET_CAPTURE);

print_r($resultados);

Use the strpos function. Its parameters are:

• $haystack : The string where the search will be done.
• $needle : Characters to fetch.
• $offset : This parameter allows you to define from which character in $haystack to start the search.

We can use this last parameter to do this type of search, like this:

function strposNth($texto, $procurar, $n){
    switch($n){
        case $n === 0:
            return false;
            break;
        case $n === 1:
            return(strpos($texto, $encontrar) + 1);
            break;
        default:
            return(strpos($texto, $procurar, strposNth($texto, $procurar, $n - 1) +
            strlen($procurar)) + 1);
            break;
    }
}

To use it:

echo strposNth("overflow", "o", 2); // 7

DEMO

$test = "Hi, How are you!";

function strCharFind($needle,$haystack){
    $return = FALSE;
    $arr = str_split($haystack,1);
    foreach($arr as $value){
        if($value==strtolower($needle)||$value==strtoupper($needle)){
            $return = TRUE;
        }
    }
    return $return;
}

var_dump(strCharFind(',',$test));//true
var_dump(strCharFind('h',$test));//true
var_dump(strCharFind('!',$test));//true
var_dump(strCharFind('?',$test));//false