Laravel 8 whenEmpty() {#collection-method}

2021-07-19 09:52 更新

whenEmpty 方法是当集合为空时，将执行给定的回调函数：

$collection = collect(['michael', 'tom']);

$collection->whenEmpty(function ($collection) {
    return $collection->push('adam');
});

$collection->all();

// ['michael', 'tom']


$collection = collect();

$collection->whenEmpty(function ($collection) {
    return $collection->push('adam');
});

$collection->all();

// ['adam']


$collection = collect(['michael', 'tom']);

$collection->whenEmpty(function ($collection) {
    return $collection->push('adam');
}, function ($collection) {
    return $collection->push('taylor');
});

$collection->all();

// ['michael', 'tom', 'taylor']

与 whenEmpty 相反的方法，请查看 whenNotEmpty 方法。

以上内容是否对您有帮助：

← Laravel 8 when() {#collection-method}

Laravel 8 whenNotEmpty() {#collection-method} →

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Laravel 8 whenEmpty() {#collection-method}

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