根據php中的鍵對數組值進行分組？

Question

我有一個這樣的數組：

$str=
   Array
(
    [No] => 101
    [Paper_id] => WE3P-1
    [Title] => "a1"
    [Author] => ABC
    [Aff_list] => "University of South Florida, Tampa, United States"
    [Abstracts] => "SLA"

)

Array
(
    [No] => 101
    [Paper_id] => WE3P-1
    [Title] => "a2"
    [Author] => DEF
    [Aff_list] => "University of South Florida, Tampa, United States"
    [Abstracts] => "SLA "

)

Array
(
    [No] => 104
    [Paper_id] => TU5A-3
    [Title] => "a3"
    [Author] => GHI
    [Aff_list] => "University of Alcala, Alcala de Henares, Spain"
    [Abstracts] => "Microwave"

)

我想根據“否”作為主鍵對數組中的元素進行分組。 輸出應如下所示：

 array(6) {
  ["No"]=>
  string(6) "101"
  ["Paper_id"]=>
  string(6) "WE3P-1"
  ["Title"]=>
  string(80) ""a-1"
  ["Author"]=>
  string(14) "ABC"
  ["Aff_list"]=>
  string(51) ""University of South Florida, Tampa, United States""
  ["Abstracts"]=>
  string(5) ""(SLA)"
"
}
array(6) {
  ["No"]=>
  string(3) "104"
  ["Paper_id"]=>
  string(6) "TU5A-3"
  ["Title"]=>
  string(40) "a2"
  ["Author"]=>
  string(20) "DEF"
  ["Aff_list"]=>
  string(48) ""University of Alcala, Alcala de Henares, Spain""
  ["Abstracts"]=>
  string(9) ""Microwave"
"
}

請注意，作者的值相對於主鍵“No”進行了合並。有人可以幫我解決這個問題嗎？

我嘗試這樣做：

foreach($paper_info as $element) {
    foreach($element as $v) {
        $id = $element['No'];
        if (!isset($out[$id])) {
            $out[$id] = [
                'No' => $element['No'],
                'Paper_id' => $element['Paper_id'],
                'Title' => $element['Title'],
                'Authors' => [],
                'Aff_list' => $element['Aff_list'],
                'Abstracts' => $element['Abstracts']
            ];
        }
        $out[$id]['Authors'][] = ['Authors' => $element['Author']];
    }
}

Answer 1

您可以使用通用函數：

function _group_by($array, $key) {
    $return = array();
    foreach($array as $val) {
        $return[$val[$key]][] = $val;
    }
    return $return;
}

我添加了一些示例代碼進行測試

<?php

$list= [
[   'No' => 101,
    'Paper_id' => 'WE3P-1',
    'Title' => "a1",
    'Author' => 'ABC',
    'Aff_list' => "University of South Florida, Tampa, United States",
    'Abstracts' => "SLA"
] ,
[   'No' => 101,
    'Paper_id' => 'WE3P-1',
    'Title' => "a2",
    'Author' => 'DEF',
    'Aff_list' => "University of South Florida, Tampa, United States",
    'Abstracts' => "SLA"
] ,
[    'No' => 104, 
    'Paper_id' => 'TUSA-3',
    'Title' => "a3",
    'Author' => 'GH1',
    'Aff_list' => "University of Alcala, Alcala de Henares, Spain",
    'Abstracts' => "Microwave"
] ];

print_r(_group_by($list, 'No'));

Answer 2

您問題中的數據格式不明確，但假設$paper_info的結構如下，這應該可以為您提供所需的輸出。

$paper_info = array(
    array(
        'No' => "101",
        'Paper_id' => "WE3P-1",
        'Title' =>"An Electrically-Small, 3-D Cube Antenna Fabricated with Additive Manufacturing",
        'Author' => "Ibrahim Nassar",
        ...
    ),
    array(
        'No' => "101",
        ...
        'Author' => "Thomas Weller",
        ...
    )
);

$out = array();
foreach($paper_info as $paper) {
    $id = $paper['No'];
    if (!isset($out[$id])) {
        $out[$id] = $paper;
        $out[$id]['Author'] = array();
    }
    $out[$id]['Author'][] = $paper['Author'];
}

您還應該在開發環境中打開警告並顯示錯誤。 我有一種感覺，它會幫助你。 在開發過程中，您可以配置 php.ini，也可以在 php 腳本的開頭插入此代碼。 只需確保在推送到生產之前將其刪除。

error_reporting(E_ALL);
ini_set('display_errors', '1');

Answer 3

感謝crafter 提供了很棒的功能，如果有人需要為多個鍵分組，我將crafter 功能編輯為：

function _group_by($array, $keys=array()) {
    $return = array();
    foreach($array as $val){
        $final_key = "";
        foreach($keys as $theKey){
            $final_key .= $val[$theKey] . "_";
        }
        $return[$final_key][] = $val;
    }
   return $return;
}

Answer 4

感謝火山口和法比奧的回答。 我更新了代碼以檢查密鑰的大小是否不大於一 (1)，不會附加下划線。

function _group_by($array, $keys=array()) {
    $return = array();
    $append = (sizeof($keys) > 1 ? "_" : null);
    foreach($array as $val){
        $final_key = "";
        foreach($keys as $theKey){
            $final_key .= $val[$theKey] . $append;
        }
        $return[$final_key][] = $val;
    }
    return $return;
}

Answer 5

我寫了另一個版本的 Crafter 答案，它從實際數組中刪除了給定的鍵。 可能會幫助某人。

    public function _group_by($array, $key) {
        $return = array();
        foreach($array as $val) {
            $return[$val[$key]] = $val;
            unset($return[$val[$key]][$key]);
        }
        return $return;
    }