<?php
$tam = 4;
$minhastring = '';
$valor = 'teste';
for ($i = 0; $i < $tam; $i++) $minhastring .= $valor . ',';
$minhastring = substr($minhastring, 0, strlen($minhastring) - 1); echo $minhastring . "\n";
$minhastring = '';
$valor = Array('teste0', 'teste1', 'teste2', 'teste3'); for ($i = 0; $i < $tam; $i++) $minhastring .= $valor[$i] . ',';
$minhastring = substr($minhastring, 0, -1); echo $minhastring . "\n";
$minhastring = implode($valor, ","); echo $minhastring;
//https://pt.stackoverflow.com/q/88228/101
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
teste,teste,teste,teste
teste0,teste1,teste2,teste3
teste0,teste1,teste2,teste3