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php实现遍历

2026-01-30 00:26:20PHP

遍历数组

使用foreach循环可以方便地遍历数组中的每个元素。对于索引数组和关联数组都适用。

$fruits = ["apple", "banana", "orange"];

foreach ($fruits as $fruit) {
    echo $fruit . "\n";
}

对于需要同时获取键和值的关联数组：

php实现遍历

$person = [
    "name" => "John",
    "age" => 30,
    "city" => "New York"
];

foreach ($person as $key => $value) {
    echo "$key: $value\n";
}

遍历对象

实现Iterator接口可以让对象可被遍历。需要实现5个方法：current(), key(), next(), rewind(), valid()。

class MyIterator implements Iterator {
    private $position = 0;
    private $array = [
        "first",
        "second",
        "third"
    ];

    public function rewind() {
        $this->position = 0;
    }

    public function current() {
        return $this->array[$this->position];
    }

    public function key() {
        return $this->position;
    }

    public function next() {
        ++$this->position;
    }

    public function valid() {
        return isset($this->array[$this->position]);
    }
}

$it = new MyIterator;
foreach($it as $key => $value) {
    echo "$key: $value\n";
}

使用数组函数遍历

array_walk()函数可以对数组每个元素应用用户自定义函数。

php实现遍历

$numbers = [1, 2, 3, 4, 5];

array_walk($numbers, function($value, $key) {
    echo "Key: $key, Value: $value\n";
});

array_map()将回调函数作用到给定数组的每个元素上。

$squared = array_map(function($n) {
    return $n * $n;
}, $numbers);

print_r($squared);

递归遍历多维数组

对于多维数组，可以使用递归方式遍历。

function traverseArray($array) {
    foreach ($array as $key => $value) {
        if (is_array($value)) {
            traverseArray($value);
        } else {
            echo "$key => $value\n";
        }
    }
}

$multiDim = [
    "fruit" => ["apple", "banana"],
    "numbers" => [1, 2, 3]
];

traverseArray($multiDim);