I needed to sort an associative array into the correct order for display, PHP has various functions for sorting arrays but I couldn’t find a simple generic one that did what I wanted. Specifically I needed to sort on several keys and wanted a reasonably tidy solution (so much easier to figure out what is going on when you come back it months\/years later).<\/p>\n
Because I was using CodeIgniter for this site I put the following function in helpers\/MY_array_helper.php so I can use it from other parts of the site. But it would work just as well if defined locally.
\n
\nfunction assoc_array_sort($a, $b, $key, $sequence = 'ASC')\n{\n\/*\n* Simple function for sorting between 2 values\n* Designed to be called within the function called by usort or uasort\n*\n* $key is the key for the associative array so if we want to compare values of $array['my_key']\n* $key would be set to 'my_key'\n*\n* Default sequence is ASC but can reverse sort by passing DESC instead\n*\/\nif (strtoupper($sequence) == 'DESC') {\n $lower = 1;\n $higher = -1;\n} else {\n $lower = -1;\n $higher = 1;\n}\n\nif ($a[$key] == $b[$key]) {\n return 0;\n } else if ($a[$key] < $b[$key]) {\n return $lower;\n } else {\n return $higher;\n }\n}\n<\/code><\/pre><\/p>\nCalling the Sort<\/h3>\n
The array I needed to sort is called $memberships so the call is;
\n
\nuasort($memberships, 'membership_sort');\n<\/code><\/pre>
\nmembership_sort is an intermediate function sitting between uasort (or usort) and assoc_array_sort. If like me you are using CodeIgniter you will need to load the array_helper before calling this function.
\n\n$this->load->helper('array'); \/\/ load array_helper so we can use the sort in MY_array_helper\n<\/code><\/pre>
\n\nfunction membership_sort($x, $y)\n {\n \/*\n * Use assoc_array_sort to determine sequence\n * but where values match call again for the next variable to be checked.\n * This should give us an array in order\n * - committee_sequence\n * - committee_name\n * - role_sequence\n * - role-name\n *\/\n $ret_var = assoc_array_sort($x, $y, 'committee_sequence','ASC');\n if ($ret_var == 0) {\n $ret_var = assoc_array_sort($x, $y, 'committee_name','ASC');\n if ($ret_var == 0) {\n $ret_var = assoc_array_sort($x, $y, 'role_sequence','ASC');\n if ($ret_var == 0) {\n $ret_var = assoc_array_sort($x, $y, 'committee_name','ASC');\n }\n }\n }\n return $ret_var;\n }\n<\/code><\/pre>
\nYou can see that the first time assoc_array_sort is called it is sorting on $memberships[‘committee_sequence’], if the values don’t match it returns -1 or 1 depending on whether the first or second value is higher. But it the values are equal it drops through to the next sort key $memberships[‘committee_name’] and repeats the process.<\/p>\nI am sure there are cleverer ways to do this, I would welcome feedback telling me of better ways, but hopefully this will be useful to somebody.<\/p>\n","protected":false},"excerpt":{"rendered":"
I needed to sort an associative array into the correct order for display, PHP has various functions for sorting arrays but I couldn’t find a simple generic one that did what I wanted. Specifically I needed to sort on several keys and wanted a reasonably tidy solution (so much easier to figure out what is […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[128,19],"tags":[129,151,145,130],"_links":{"self":[{"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/posts\/346"}],"collection":[{"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/comments?post=346"}],"version-history":[{"count":9,"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/posts\/346\/revisions"}],"predecessor-version":[{"id":354,"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/posts\/346\/revisions\/354"}],"wp:attachment":[{"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/media?parent=346"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/categories?post=346"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cotsweb.com\/blog\/wp-json\/wp\/v2\/tags?post=346"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}