问如何将命名密钥分配给数组？

EN

<?php
$speciesarray = array("Amanita aprica"=>"species/Amanita_aprica.html",
    "Amanita augusta"=>"species/Amanita_augusta.html",
    "Amanita calyptratoides"=>"species/Amanita_calyptratoides.html",
    "Amanita calyptroderma"=>"species/Amanita_calyptroderma.html",
    "Amanita constricta"=>"species/Amanita_constricta.html",
    "Amanita gemmata"=>"species/Amanita_gemmata.html",
    "Amanita magniverrucata"=>"species/Amanita_magniverrucata.html",
    "Amanita muscaria"=>"species/Amanita_muscaria.html",
    "Amanita novinupta"=>"species/Amanita_novinupta.html",
    "Amanita ocreata"=>"species/Amanita_ocreata.html",
    "Amanita pachycolea"=>"species/Amanita_pachycolea.html",
    "Amanita pantherina"=>"species/Amanita_pantherina.html",
    "Amanita phalloides"=>"species/Amanita_phalloides.html",
    "Amanita porphyria"=>"species/Amanita_porphyria.html",
    "Amanita protecta"=>"species/Amanita_protecta.html",
    "Amanita pruittii"=>"species/Amanita_pruittii.html",
    "Amanita silvicola"=>"species/Amanita_silvicola.html",
    "Amanita smithiana"=>"species/Amanita_smithiana.html",
    "Amanita vaginata"=>"species/Amanita_vaginata.html",
    "Amanita velosa"=>"species/Amanita_velosa.html",
    "Amanita vernicoccora"=>"species/Amanita_vernicoccora.html");

shuffle($speciesarray); // Randomize the species array
$speciesarray = array_slice($speciesarray, 0, 5); // Select 5 elements from the randomized species array
reset($speciesarray);
$choice = key($speciesarray); // Get the first key from the reduced array
shuffle($speciesarray); // Randomize again

/* For debugging */
print_r($speciesarray);
echo("<br/>")
print_r($choice);
?>

Array ( [Amanita silvicola] => species/Amanita_silvicola.html [Amanita gemmata] => species/Amanita_gemmata.html [Amanita calyptratoides] => species/Amanita_calyptratoides.html [Amanita vaginata] => species/Amanita_vaginata.html [Amanita phalloides] => species/Amanita_phalloides.html )
Amanita silvicola

Array ( [0] => species/Amanita_silvicola.html [1] => species/Amanita_gemmata.html [2] => species/Amanita_calyptratoides.html [3] => species/Amanita_vaginata.html [4] => species/Amanita_phalloides.html )
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