- strcmp: documentation ( source)
- array_filter: documentation ( source)
- preg_split: documentation ( source)
- usort: documentation ( source)
- strtolower: documentation ( source)
<?php
$x = '
\Delta
\Gamma
\Lambda
\Omega
\Phi
\Pi
\Psi
\Sigma
\Theta
\Upsilon
\Xi
\alpha
\beta
\chi
\delta
\epsilon
\eta
\gamma
\gamma
\kappa
\lambda
\mu
\nu
\omega
\phi
\pi
\psi
\rho
\sigma
\tau
\theta
\upsilon
\varepsilon
\varphi
\varpi
\varrho
\varsigma
\vartheta
\xi
\zeta
';
$x = array_filter(preg_split('/\s+/', $x));
usort($x, function ($a, $b) {
return strcmp(strtolower($a), strtolower($b));
});
foreach ($x as $xx) {
echo $xx, "\n";
}