我使用嵌套数组来创建一个2D矩阵。使用嵌套的foreach循环，很容易找到行中所有值的总和。然而，我不知道如何对每一列求和。例如:我想找出score对每个item的和。
有什么建议吗?谢谢你! !:)
PS:注意数组中的一些单元格没有值。这些将被视为0。
跨行求和
foreach($critics as $array) {
foreach($array as $item => $score) {
$row_sum += $score;
}
}
$critics['Lisa Rose'] = array(
'Lady in the water' => 2.5,
'Snakes on a plane' => 3.5,
'Just my luck' => 3.0,
'Superman returns' => 3.5,
'You, me and dupree' => 2.5,
'The night listener' => 3.0
);
$critics['Gene Seymour'] = array(
'Lady in the water' => 3.0,
'Snakes on a plane' => 3.5,
'Just my luck' => 1.5,
'Superman returns' => 5.0,
'You, me and dupree' => 3.5,
'The night listener' => 3.0
);
$critics['Michael Phillips'] = array(
'Lady in the water' => 2.5,
'Snakes on a plane' => 3.0,
'Superman returns' => 3.5,
'The night listener' => 4
);
$critics['Claudia Puig'] = array(
'Snakes on a plane' => 3.5,
'Just my luck' => 3.0,
'Superman returns' => 4.5,
'You, me and dupree' => 4.0,
'The night listener' => 2.5
);
$critics['Mick LaSalle'] = array(
'Lady in the water' => 3.0,
'Snakes on a plane' => 4.0,
'Just my luck' => 2.0,
'Superman returns' => 3.0,
'You, me and dupree' => 3.0,
'The night listener' => 2.0
);
$critics['Jack Matthews'] = array(
'Lady in the water' => 3.0,
'Snakes on a plane' => 4.0,
'Just my luck' => 2.0,
'Superman returns' => 3.0,
'You, me and dupree' => 3.5,
);
$critics['Toby'] = array(
'Snakes on a plane' => 4.5,
'Just my luck' => 1.0,
'Superman returns' => 4.0
);
// loop through each critic
foreach($critics as $array){
// loop through each film
foreach(array_keys($array) as $film){
// add the score to the film's entry in the films array (or create the entry)
$films[$film] += $array[$film];
}
}
print_r($films);
输出如下:
Array
(
[Lady in the water] => 14
[Snakes on a plane] => 26
[Just my luck] => 12.5
[Superman returns] => 26.5
[You, me and dupree] => 16.5
[The night listener] => 14.5
)
使用array_keys()确定每个评论家评分的每部电影的名称。将该电影的值添加到主数组$scores中，该数组具有与键相同的电影名称:
$scores = array();
foreach ($critics as $critic) {
// Get the movies scored by this critic
$movies = array_keys($critic);
// Add each movie's score to the master list's score
foreach ($movies as $movie) {
// Add it to the score if the movie is already in the master list
if (isset($scores[$movie])) {
$scores[$movie] += $critic[$movie];
}
// Otherwise initialize this movie in the master list
else $scores[$movie] = $critic[$movie];
}
}
print_r($scores);
Array
(
[Lady in the water] => 14
[Snakes on a plane] => 26
[Just my luck] => 12.5
[Superman returns] => 26.5
[You, me and dupree] => 16.5
[The night listener] => 14.5
)
$scores = array();
foreach ($critics as $items) {
foreach ($items as $item => $score) {
if (isset($scores[$item]))
$scores[$item] += $score;
else
$scores[$item] = $score;
}
}