忽略 array_merge 中的空字符串

Question

我有 3 个 if 语句（见代码）。每个用于创建电子邮件地址数组。如何将这 3 个字符串合并为 $to（知道它们可能为空或什至不存在）？

显然这不起作用...

    if ( in_array('client', $measurement_mail_report_recipients) ) {

        $measurement_client_id = intval($_POST['acf']['field_5e147914518a6']);
        $list1 = array();

        if (have_rows('company_email_addresses', $measurement_client_id)) {
            while (have_rows('company_email_addresses', $measurement_client_id)) {
                the_row();
                $list1[] = get_sub_field('company_email_address');
            }
        }

    }

    if ( in_array('contact', $measurement_mail_report_recipients) ) {

        $measurement_contact_id = intval($_POST['acf']['field_5e149714d044e']);
        $list2 = array();

        if (have_rows('contact_email_addresses', $measurement_contact_id)) {
            while (have_rows('contact_email_addresses', $measurement_contact_id)) {
                the_row();
                $list2[] = get_sub_field('contact_email_address');
            }
        }

    }

    if ( in_array('extra', $measurement_mail_report_recipients) ) {

        $measurement_mail_extra_recipients = $_POST['acf']['field_5f71d4eaaf381'];

        if ( $measurement_mail_extra_recipients ) {
            $list3 = array();
            foreach( $measurement_mail_extra_recipients as $measurement_mail_extra_recipient ) {
                $list3[] = $measurement_mail_extra_recipient['field_5f71d55aaf382'];
            }
        }

    }

    $to         = array_merge($list1, $list2, $list3);

Answer 1

希望这对您有所帮助：

合并数组
遍历合并后的数组
检查当前元素是""还是null
如果是这样，用 array_splice()

Answer 2

$myArray = [];
$myArray2 = [];
// If undefined the value becomes false instead of error (always do this)
$myArray2["value1"] = $_POST["post-value"] ?? false;

// Always use isset to check if a variable is defined
if(isset($myArray["some-value"])){
    // do some work
}
// proceed to remove an associated array or any variable
unset($myArray2["value1"]);// You can also unset any variable

PHP isset function returns 如果变量已经定义则为真否则为假，所以用它来检查数组是否存在。要检查数组是否具有值，请使用比较运算符，如：sth equals another。删除关联数组或任何变量，如上文所述取消设置。

Answer 3

我知道我忘记了什么。我必须将数组声明为空，以防 if 语句 未被触发。检查下面我的工作代码：

    if ( in_array('client', $measurement_mail_report_recipients) ) {

        $measurement_client_id = intval($_POST['acf']['field_5e147914518a6']);
        $list1 = array();

        if (have_rows('company_email_addresses', $measurement_client_id)) {
            while (have_rows('company_email_addresses', $measurement_client_id)) {
                the_row();
                $list1[] = get_sub_field('company_email_address');
            }
        }

    } else { $list1 = array(); }

    if ( in_array('contact', $measurement_mail_report_recipients) ) {

        $measurement_contact_id = intval($_POST['acf']['field_5e149714d044e']);
        $list2 = array();

        if (have_rows('contact_email_addresses', $measurement_contact_id)) {
            while (have_rows('contact_email_addresses', $measurement_contact_id)) {
                the_row();
                $list2[] = get_sub_field('contact_email_address');
            }
        }

    } else { $list2 = array(); }

    if ( in_array('extra', $measurement_mail_report_recipients) ) {

        $measurement_mail_extra_recipients = $_POST['acf']['field_5f71d4eaaf381'];

        if ( $measurement_mail_extra_recipients ) {
            $list3 = array();
            foreach( $measurement_mail_extra_recipients as $measurement_mail_extra_recipient ) {
                $list3[] = $measurement_mail_extra_recipient['field_5f71d55aaf382'];
            }
        }

    } else { $list3 = array(); }

    $recipients = array_merge($list1, $list2, $list3);
    $to         = array_filter($recipients);

Answer 4

//Use this method
$array1 = [0,1,3,6];
$array2 = [];
$array3 = ["a","b","c"];
/*
 Store all the collective array in one array 
 the array_1,2 style will help to resolve things inside for loop
*/
$biggerArray = ["array_1"=>$array1, "array_2"=>$array2, "array_3"=>$array3];
$bigger2 = [];
for($i = 0; $i < 3; $i++){
    foreach($biggerArray["$i"] as $k => $v){
        if(!$biggerArray["$i"][$k]){
            // the value is empty
        }else{
            // it's not empty
            if(!isset($bigger2["array_$i"]){
                $bigger2["array_$i"] = [];
            }else{
                array_push($bigger2["array_$i"],$biggerArray["$i"][$k]);
            }
        }
    }
}
// with function return $bigger2 array

忽略 array_merge 中的空字符串

Ignore empty strings in array_merge

php

arrays

array-merge

is-empty