PHP多维数组按指定键值筛选返回主数组的实现方案

Hey there! Let's tackle your two PHP array filtering problems one by one — I've run into similar recursive snags before, so I know exactly where you might be tripping up.

Problem 1: Filter Program Arrays with "New Jersey" Campuses #

First, let's assume your $programs array looks something like this (I'm using a realistic example to make this concrete):

$programs = [
    [
        'id' => 1,
        'name' => 'Computer Science',
        'campuses' => [
            ['campus_title_override' => 'New Jersey - Newark'],
            ['campus_title_override' => 'New York - Manhattan']
        ]
    ],
    [
        'id' => 2,
        'name' => 'Mechanical Engineering',
        'campuses' => [
            ['campus_title_override' => 'California - LA']
        ]
    ],
    [
        'id' => 3,
        'name' => 'Business Administration',
        'campuses' => [
            ['campus_title_override' => 'New Jersey - Princeton'],
            ['campus_title_override' => 'Pennsylvania - Philly']
        ]
    ]
];

Your recursive function returning empty is almost certainly due to missing checks for nested array existence or not properly triggering a match when the term is found. Here are two solid solutions:

Option 1: Iterative Filter (Great for Debugging) #

This is straightforward and easier to trace if you're still troubleshooting:

function filterProgramsByCampus($programs, $searchTerm) {
    $filteredPrograms = [];
    
    foreach ($programs as $program) {
        // Loop through each campus in the current program
        foreach ($program['campuses'] as $campus) {
            // Check if the campus title contains your search term
            if (str_contains($campus['campus_title_override'], $searchTerm)) {
                $filteredPrograms[] = $program;
                break; // Stop checking this program's campuses once we find a match
            }
        }
    }
    
    return $filteredPrograms;
}

// Usage example
$matchingPrograms = filterProgramsByCampus($programs, 'New Jersey');
print_r($matchingPrograms); // Returns programs 1 and 3

Option 2: Recursive Filter (For Deeply Nested Campuses) #

If your campuses array might have deeper nested sub-campuses, recursion is the way to go. The key here is adding checks to avoid errors from missing fields:

// Helper function to check if any campus (or sub-campus) matches
function hasMatchingCampus($campuses, $searchTerm) {
    foreach ($campuses as $campus) {
        // First check if the current campus has the target field and matches
        if (isset($campus['campus_title_override']) && str_contains($campus['campus_title_override'], $searchTerm)) {
            return true;
        }
        
        // If there are nested campuses, recurse into them
        if (isset($campus['campuses']) && is_array($campus['campuses'])) {
            if (hasMatchingCampus($campus['campuses'], $searchTerm)) {
                return true;
            }
        }
    }
    return false;
}

// Main function to filter programs
function filterProgramsRecursive($programs, $searchTerm) {
    return array_filter($programs, function($program) use ($searchTerm) {
        return hasMatchingCampus($program['campuses'], $searchTerm);
    });
}

// Usage example
$matchingPrograms = filterProgramsRecursive($programs, 'New Jersey');
print_r($matchingPrograms);

Problem 2: Filter Campus Arrays with Matching Programs #

This is a mirror of the first problem — we just flip the hierarchy. Let's assume your $campuses array looks like this:

$campuses = [
    [
        'id' => 1,
        'campus_name' => 'New Jersey - Newark',
        'programs' => [
            ['program_name' => 'Computer Science'],
            ['program_name' => 'Mathematics']
        ]
    ],
    [
        'id' => 2,
        'campus_name' => 'California - LA',
        'programs' => [
            ['program_name' => 'Mechanical Engineering']
        ]
    ],
    [
        'id' => 3,
        'campus_name' => 'New Jersey - Princeton',
        'programs' => [
            ['program_name' => 'Business Administration'],
            ['program_name' => 'Computer Science']
        ]
    ]
];

Iterative Filter (Simple & Direct) #

function filterCampusesByProgram($campuses, $searchTerm) {
    $filteredCampuses = [];
    
    foreach ($campuses as $campus) {
        foreach ($campus['programs'] as $program) {
            // Swap out 'program_name' for your actual program field to match
            if (str_contains($program['program_name'], $searchTerm)) {
                $filteredCampuses[] = $campus;
                break;
            }
        }
    }
    
    return $filteredCampuses;
}

// Usage example: Filter campuses with "Computer Science" programs
$matchingCampuses = filterCampusesByProgram($campuses, 'Computer Science');
print_r($matchingCampuses); // Returns campuses 1 and 3

Recursive Filter (For Deeply Nested Programs) #

If your programs have nested sub-programs, use this recursive approach:

function hasMatchingProgram($programs, $searchTerm) {
    foreach ($programs as $program) {
        if (isset($program['program_name']) && str_contains($program['program_name'], $searchTerm)) {
            return true;
        }
        
        if (isset($program['programs']) && is_array($program['programs'])) {
            if (hasMatchingProgram($program['programs'], $searchTerm)) {
                return true;
            }
        }
    }
    return false;
}

function filterCampusesRecursive($campuses, $searchTerm) {
    return array_filter($campuses, function($campus) use ($searchTerm) {
        return hasMatchingProgram($campus['programs'], $searchTerm);
    });
}

// Usage example
$matchingCampuses = filterCampusesRecursive($campuses, 'Computer Science');
print_r($matchingCampuses);

Quick Notes: #

• If you're on PHP < 8.0, replace str_contains($haystack, $needle) with strpos($haystack, $needle) !== false (since str_contains was added in 8.0).
• Always use isset() checks for array fields — missing fields will cause errors that can make your functions return empty unexpectedly (this is probably why your original recursive function failed!).
• Swap out the field names (like program_name) for whatever actual fields you need to match in your real array.

内容的提问来源于stack exchange，提问作者unixmiah