Question

我正在使用PHP中的多维数组。我想检测是否存在类似的值，然后计算相似值的数量并输出结果。例如，给定以下数组：

$products = 
    Array
    (
        [0] => Array
            (
                [price] => 100
                [product] => cloths
                [qty] => 3
            )

        [1] => Array
            (
                [price] => 101
                [product] => cloths
                [qty] => 10
            )

        [2] => Array
            (
                [price] => 102
                [product] => cloths
                [qty] => 16
            )

        [3] => Array
            (
                [price] => 103
                [product] => cloths
                [qty] => 1
            )

        [4] => Array
            (
                [price] => 108
                [product] => cloths
                [qty] => 6
            )

        [5] => Array
            (
                [price] => 107
                [product] => cloths
                [qty] => 4
            )

        [6] => Array
            (
                [price] => 109
                [product] => cloths
                [qty] => 5
            )

        [7] => Array
            (
                [price] => 105
                [product] => cloths
                [qty] => 2
            )

        [8] => Array
            (
                [price] => 104
                [product] => cloths
                [qty] => 5
            )

        [9] => Array
            (
                [price] => 106
                [product] => cloths
                [qty] => 2
            )

        [10] => Array
            (
                [price] => 111
                [product] => cloths
                [qty] => 1
            )

    )

如何解决这个问题？

foreach ($products as $key => $product) {
    $price = $product['price'];
    //now using this price how can i get all keys which are equal to this price
}

修改我试过这个但没有用

echo $key = array_search(100, array_column($products, 'price'));

Answer 1

尝试以下内容：

$keys =  array_keys(array_filter($product, function($val) {return $val['price'] == 100; })

Answer 2

我会创建一个包含价格作为键和产品键的数组作为值：

int main()
{
    std::srand(std::time(0));

    using std::size_t;

    const size_t N = 20000;

    std::string alphabet("ACGT");

    // stuff the ballot
    std::vector<std::string> v(100, "CCGT");

    // build a properly weighted alphabet string
    // to give each letter equal chance of appearing
    // in the final string

    std::string weighted;

    // This could be scaled down to make the weighted string much smaller

    for(size_t i = 0; i < (N - 200) / 4; ++i) // already have 200 Cs
        weighted += "C";

    for(size_t i = 0; i < (N - 100) / 4; ++i) // already have 100 Ns & Gs
        weighted += "GT";

    for(size_t i = 0; i < N / 4; ++i)
        weighted += "A";

    size_t remaining = N - (v.size() * 4);

    // add the remaining characters to the weighted string
    std::string s;
    for(size_t i = 0; i < remaining; ++i)
        s += weighted[std::rand() % weighted.size()];

    // add the random "4 char" sequences to the vector so
    // we can randomly distribute the pre-loaded special "4 char"
    // sequence among them.
    for(std::size_t i = 0; i < s.size(); i += 4)
        v.push_back(s.substr(i, 4));

    // distribute the "4 char" sequences randomly
    std::random_shuffle(v.begin(), v.end());

    // rebuild string s from vector
    s.clear();
    for(auto&& seq: v)
        s += seq;

    std::cout << s.size() << '\n'; // should be N
}

现在，$prices = array(); foreach ($products as $key => $product) { $prices[$product['price']][] = $key; }包含所有产品密钥的数组，其中price = 105（在具体示例中，它只有一个：$prices[105]）：

如何使用php

2 个答案: