Overview
ListCollection provides various filtering methods. All filtering operations return a new ListCollection with sequential integer keys.
filter()
Filter elements using a callback. Elements that return true are kept.
Signature
public function filter(callable $callback = null): static
callback
callable(TValue, int): bool
default:"null"
Optional callback that receives value and key. Returns true to keep the element. If omitted, removes falsy values.
Examples
Filter with callback
$list = new ListCollection([1, 2, 3, 4, 5]);
$filtered = $list->filter(fn(int $v): bool => $v > 2);
$filtered->all();
// [0 => 3, 1 => 4, 2 => 5]
Filter without callback (removes falsy values)
$list = new ListCollection([0, 1, '', 'hello', null, false, true]);
$filtered = $list->filter();
$filtered->all();
// [0 => 1, 1 => 'hello', 2 => true]
reject()
Filter elements by rejecting those that match the callback.
Signature
public function reject(callable $callback): static
callback
callable(TValue, int): bool
required
Callback that receives value and key. Returns true to reject (remove) the element.
Examples
$list = new ListCollection([1, 2, 3, 4, 5]);
$result = $list->reject(fn(int $v): bool => $v % 2 === 0);
$result->all();
// [0 => 1, 1 => 3, 2 => 5]
where()
Filter elements where a field matches a value.
Signature
public function where($key, $operator = null, $value = null): static
operator
string|mixed
default:"null"
Comparison operator or value if no operator specified.
The value to compare against.
Examples
$list = new ListCollection([
['active' => true, 'name' => 'A'],
['active' => false, 'name' => 'B'],
['active' => true, 'name' => 'C'],
]);
$result = $list->where('active', true);
$result->all();
// [
// 0 => ['active' => true, 'name' => 'A'],
// 1 => ['active' => true, 'name' => 'C']
// ]
whereIn()
Filter elements where a field’s value is in an array.
Signature
public function whereIn($key, $values, $strict = false): static
Array of acceptable values.
Examples
$list = new ListCollection([
['id' => 1, 'name' => 'Alice'],
['id' => 2, 'name' => 'Bob'],
['id' => 3, 'name' => 'Charlie'],
]);
$result = $list->whereIn('id', [1, 3]);
$result->all();
// [
// 0 => ['id' => 1, 'name' => 'Alice'],
// 1 => ['id' => 3, 'name' => 'Charlie']
// ]
except()
Return all elements except those at specified indices.
Signature
public function except($keys): static
Index or array of indices to exclude.
Examples
$list = new ListCollection(['a', 'b', 'c', 'd']);
$result = $list->except([1, 3]);
$result->all();
// [0 => 'a', 1 => 'c']
only()
Return only the elements at specified indices.
Signature
public function only($keys): static
Index or array of indices to include.
Examples
$list = new ListCollection(['a', 'b', 'c', 'd']);
$result = $list->only([0, 2]);
$result->all();
// [0 => 'a', 1 => 'c']
unique()
Return only unique elements.
Signature
public function unique($key = null, $strict = false): static
key
string|callable|null
default:"null"
Field name or callback to determine uniqueness.
Examples
$list = new ListCollection([1, 2, 2, 3, 3, 3]);
$unique = $list->unique();
$unique->all();
// [0 => 1, 1 => 2, 2 => 3]
diff()
Return elements not present in the given array.
$list = new ListCollection([1, 2, 3, 4, 5]);
$diff = $list->diff([2, 4]);
$diff->all();
// [0 => 1, 1 => 3, 2 => 5]
intersect()
Return elements present in both the collection and given array.
$list = new ListCollection([1, 2, 3, 4, 5]);
$intersect = $list->intersect([2, 4, 6]);
$intersect->all();
// [0 => 2, 1 => 4]
Key Points
- All filtering methods return a new
ListCollection with sequential keys
filter() keeps matching elements, reject() removes themwhere() and whereIn() are useful for filtering arrays of objects/arraysexcept() and only() work with indicesunique() removes duplicate values- Results are always reindexed to maintain list structure (0, 1, 2, …)