如何缩短多个if语句的代码？

Question

I was thinking about this some time. I'm using a lot if statements, and sometimes I have a lot of them. I know I can use switch to shorten a bit the code. Is there another way to shorten them?

Let's say we have this example:

$all_conditions = '';

        if($post_status != ""){
            $conditions[] = "posts.post_status = '".$post_status."'";
        }
        if($post_type != ""){
            $conditions[] = "posts.post_type = '".$post_type."'";
        }
        if($meta_key != ""){
            $conditions[] = "postmeta.meta_key = '".$meta_key."'";
        }
        if($meta_value != ""){
            $conditions[] = "postmeta.meta_value = '".$meta_value."'";
        }
        if($date_begin != "" && $date_end != ""){
            $conditions[] = "( posts.post_date BETWEEN '".$date_begin."' AND '".$date_end."' )";
        }
        if(count($conditions)>0){
            $all_conditions = implode(" AND ",$conditions);
        }
        if($all_conditions != ""){
            $all_conditions = "WHERE ".$all_conditions;
        }

What should I do to not repeat all those if's?

Answer 1

Try this:

<?php
$all_conditions = '';
$checkArr = array('post_status' =>  'posts.post_status',
                  'post_type'   =>  'posts.post_type',
                  'meta_key'    =>  'postmeta.meta_key',
                  'meta_value'  =>  'postmeta.meta_value');
foreach ($checkArr AS $key => $val) {
    if (${$key} != '') {
        $conditions[] = "$val = '${$key}'";
    }
}
if($date_begin != "" && $date_end != ""){
    $conditions[] = "( posts.post_date BETWEEN '".$date_begin."' AND '".$date_end."' )";
}
if(count($conditions)>0){
    $all_conditions = "WHERE ".implode(" AND ",$conditions);
}  ?>