基于year列合并两个数组并整合对应字段的技术问询

Here's a clean and efficient way to merge your two arrays based on the year column, combining corresponding fields and including all years from both datasets:

Step-by-Step Explanation #

1. Create Lookup Arrays: Convert both input arrays into associative arrays where keys are year values. This lets us quickly access voucher and sample values without slow nested loops.
2. Collect Unique Years: Gather all distinct years from both lookup arrays to ensure no entries are missed.
3. Build Merged Array: For each unique year, construct an entry that includes the year, plus the voucher (if present) and sample (if present).

Code Implementation #

// Your original arrays
$array1 = [
    ['year' => 2016, 'voucher' => 7],
    ['year' => 2017, 'voucher' => 9],
    ['year' => 2018, 'voucher' => 6],
    ['year' => 2015, 'voucher' => 1],
    ['year' => 2014, 'voucher' => 2]
];

$array2 = [
    ['year' => 2018, 'sample' => 4],
    ['year' => 2017, 'sample' => 3],
    ['year' => 2019, 'sample' => 5] // Example of a year only in array2
];

// Create lookup arrays for quick value access
$voucherLookup = array_column($array1, 'voucher', 'year');
$sampleLookup = array_column($array2, 'sample', 'year');

// Get all unique years from both datasets
$allYears = array_unique(array_merge(array_keys($voucherLookup), array_keys($sampleLookup)));
sort($allYears); // Optional: Sort years chronologically

// Build the merged array
$mergedArray = [];
foreach ($allYears as $year) {
    $mergedArray[] = [
        'year' => $year,
        'voucher' => $voucherLookup[$year] ?? null, // Use null if voucher doesn't exist
        'sample' => $sampleLookup[$year] ?? null    // Use null if sample doesn't exist
    ];
}

// Output the result
print_r($mergedArray);

Example Output #

Array
(
    [0] => Array
        (
            [year] => 2014
            [voucher] => 2
            [sample] => 
        )

    [1] => Array
        (
            [year] => 2015
            [voucher] => 1
            [sample] => 
        )

    [2] => Array
        (
            [year] => 2016
            [voucher] => 7
            [sample] => 
        )

    [3] => Array
        (
            [year] => 2017
            [voucher] => 9
            [sample] => 3
        )

    [4] => Array
        (
            [year] => 2018
            [voucher] => 6
            [sample] => 4
        )

    [5] => Array
        (
            [year] => 2019
            [voucher] => 
            [sample] => 5
        )
)

Customization Tips #

• If you prefer 0 instead of null for missing values, replace ?? null with ?? 0.
• Remove the sort($allYears) line if you don't need the merged array to be in chronological order.
• This approach is efficient even for large arrays, as it avoids nested loops and uses O(n + m) time complexity.

内容的提问来源于stack exchange，提问作者Hem's Gurjar