3v4l.org

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<?php echo uppercase_letters('ac84894987984987AD', 0, 2); echo ' '; echo uppercase_letters('acaDdf984987Ad',0,10); function uppercase_letters($str, $start, $end){ $strlen = strlen($str); $str_uc = strtoupper(substr($str, $start, $end)); $then = substr($str, $end, $strlen); return $str_uc . $then; }
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.35, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
AC84894987984987AD ACADDF984987Ad

preferences:
235.97 ms | 405 KiB | 369 Q