构建与QUOT;交叉＆QUOT;或QUOT;透视＆QUOT;从PHP中的数组表 [英] Building a "crosstab" or "pivot" table from an array in php

问题描述

我有同样的定义对象的数组如下：

I have an array of objects defined similarly to the below:

$scores = array();

// Bob round 1
$s = new RoundScore();
$s->Round_Name = 'Round 1';
$s->Player_Name = 'Bob';
$s->Score = 10;
$scores[0] = $s;

// Bob round 2
$s = new RoundScore();
$s->Round_Name = 'Round 2';
$s->Player_Name = 'Bob';
$s->Score = 7;
$scores[1] = $s;

// Jack round 1
$s = new RoundScore();
$s->Round_Name = 'Round 1';
$s->Player_Name = 'Jack';
$s->Score = 6;
$scores[2] = $s;

// Jack round 2
$s = new RoundScore();
$s->Round_Name = 'Round 2';
$s->Player_Name = 'Jack';
$s->Score = 12;
$scores[3] = $s;

如果我遍历并转储 $分数对象插入表中，它看起来是这样的：

If I loop through and dump the $scores object into a table, it will look something like this:

Round_Name   Player   Score
----------------------------
Round 1      Bob        10
Round 2      Bob         7
Round 1      Jack        6
Round 2      Jack       12

我想要什么，但是，是这样的：

What I want, however, is something like this:

Player  Round 1  Round 2  Total
-------------------------------
Bob       10        7       17
Jack       6       12       18

我不打算提前知道多轮或者球员怎么还会有，让我们只说我无法改变对象的构造方式。

I'm not going to know in advance how many rounds or players there'll be and let's just say I can't change the way the objects are constructed.

什么是在PHP中做到这一点的最有效方法是什么？

What's the most efficient way to do this in php?

推荐答案

如果我们可以假设：

• 分数的数组中的顺序始终是为了通过玩家的名字
  然后由循环数


• 轮的数量是相同的，每个玩家

那么，我们能做的就是打印每名球员的得分，因为我们通过阵列移动在计算的过程中，但总复位，如果我们看到一个新的播放器：

Then, what we can do is print each player's score as we moved through the array while calculating the total in the process but resetting it if we see a new player:

$round_count = 0;
$header_printed = false;
$current_player = NULL;
$current_total = 0;
$current_output_line = "";
foreach ($scores as $score) {
    // Check whether we have to move to a new player
    if ($score->Player_Name != $current_player) {
        // Check whether we have anything to print before
        // resetting the variables
        if (!is_null($current_player)) {
            if (!$header_printed) {
                printf("%-10s", "Player");
                for ($i = 0; $i < $round_count; $i++) {
                    printf("%-10s", "Round $i");
                }
                printf("%-10s\n", "Total");

                $header_printed = true;
            }

            $current_output_line .= sprintf("%5d\n", $current_total);
            print $current_output_line;
        }

        // Reset the total and various variables for the new player
        $round_count = 0;
        $current_player = $score->Player_Name;
        $current_total = 0;
        $current_output_line = sprintf("%-10s", $score->Player_Name);
    }

    $round_count++;
    $current_total += $score->Score;
    $current_output_line .= sprintf("%5d     ", $score->Score);
}
// The last player is not printed because we exited the loop 
// before the print statement, so we need a print statement here.
if ($current_output_line != "") {
    $current_output_line .= sprintf("%5d\n", $current_total);
    print $current_output_line;
}

示例输出：

Player    Round 0   Round 1   Total
Bob          10         7        17
Jack          6        12        18

这应该是相当有效的，因为它只能通过数组去一次。

This should be quite efficient because it only goes through the array once.

这篇关于构建与QUOT;交叉＆QUOT;或QUOT;透视＆QUOT;从PHP中的数组表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！