This is a lazy, fluent and functional library for PHP 7.
I have one for PHP 5 in the works as well :)
Please bear with me, I will update this, create test files etc as fast and as often I can.
- drop(int $noOfRowsToDrop)
- drop_until(callable $predicate)
- map(callable $transform)
- take(int $noOfRowsToTake)
- take_while(callable $predicate)
- filter(callable $predicate)
- exclude(callable $predicate)
- column($column_key)
- columns(...$column_keys)
- delete_columns(...$column_keys)
- reindex()
- key_from_column($column_key)
- sort_asc_on_key()
- sort_desc_on_key()
- sort_desc_on_column($column_key)
- group_on_column($column_key)
- group_on_key()
- all(callable $predicate)
- any(callable $predicate)
- to_array()
- reduce(callable $reduce_function)
- sum()
- product()
- odds()
- evens()
- vowels()
- consonants()
Factorial function:
function factorial($n){
return \LFF7\from_range(1,$n) -> product();
}Finding the sum of the first one million natural numbers:
$sum =
\LFF7\naturals()
->take(1000000)
->sum();Finding the sum of all the values in the third column of a CSV file:
$sum =
\LFF7\from_csv_file('myfile.csv')
->column(2)
->sum();(It will work with a 1TB file, because it's all lazy :) )
Finding the product of the even numbers of an array:
$product =
\LFF7\from_array([1, 5, 7, 9, 0, 2, 3, 6, 5, 2, 6])
->evens()
->product();(It will stop after finding a zero and return it as the final value of the computation).
A complex computation from a CSV file:
Let's say we have a CSV file with the following structure:
| Name | Date | Sales |
|---|---|---|
| Danny | 2017-01-03 | 100.25 |
| George | 2017-01-03 | 90.00 |
| Linda | 2017-01-03 | 190.00 |
| Danny | 2017-01-04 | 200.00 |
| George | 2017-01-04 | 254.00 |
| Linda | 2017-01-04 | 810.99 |
| ... | ... | ... |
We would like to obtain the sum of the sales on each person, ordered by name.
$arr =
\LFF7\from_csv_file('sales.csv')
->columns(0, 2)
->reindex()
->group_on_column(0)
->sort_asc_on_key()
->map(
function($v){
return
\LFF\from_array($v)
->column(1)
->sum();
}
)
->to_array();Just require LFF7.php.
- Obtain a generator wrapped in an object using the generator creation functions
from_array,from_filea.s.o. Example:
$generator = from_array([1, 2, 3, 4, 5, 6, 7, 8, 9]);- Fluently chain methods that express your desired computation. For example:
$computation = $generator->odds()->less_than(6);- Perform the actual computation (note the function invocation):
foreach($computation() as $value){
echo $value, " ";
}From an array:
$gen = \LFF7\from_array([1, 2, 3, 4, 5]);
From a range of integers:
$gen = \LFF7\from_range(10, 2000000);
(the range of integers starting with 10 and ending with 2000000)
All natural numbers:
$gen = \LFF7\naturals();
(returns a generator lazily yielding all natural numbers)
From a file:
$gen = \LFF7\from_file('myfile.txt');
(returns a generator that lazily yields one row at a time, as string)
From a CSV file:
$gen = \LFF7\from_csv_file('myfile.csv');
(returns a generator that lazily yields one row at a time, as an array)
Returns a new generator that drops the first $noOfRowsToDrop rows from the current generator. Lazy/Fluent
Example: \LFF7\from_array([1, 2, 3, 4, 5])->drop(2)->to_array() produces the array [3, 4, 5].
Returns a new generator that drops rows from the current one until $predicate returns true. Lazy/Fluent
Example: \LFF7\from_array([1, 2, 3, 4, 5])->drop_until(function($n){return $n > 3;})->to_array() produces the array [4, 5].
Returns a new generator that applies the $transform callable to items yielded from the current generator. Lazy/Fluent
Example: \LFF7\from_array([1, 2, 3, 4, 5])->map(function($x){return $x++;})->to_array() produces the array [2, 3, 4, 5, 6].
Returns a new generator that will yield at most $noOfRowsToTake from the current generator. Lazy/Fluent
Example: \LFF7\naturals()->take(100) will yield the first 100 natural numbers, i.e 0, 1, 2, ..., 99.
Returns a new generator that yields rows from the current one while $predicate returns true. Lazy/Fluent
Example: \LFF7\from_array([1, 2, 3, 4, 5])->take_while(function($n){return $n < 3;})->to_array() produces the array [1, 2].
Returns a new generator that yields rows from the current one for which $predicate returns true. Lazy/Fluent
Example: \LFF7\from_array([1, 2, 3, 4, 5])->filter(function($n){return $n % 2 == 0;})->to_array() produces the array [2, 4].
(Please note that method evens() does the same thing.)
Returns a new generator that yields rows from the current one for which $predicate returns false. Lazy/Fluent
Example: \LFF7\from_array([1, 2, 3, 4, 5])->exclude(function($n){return $n % 2 == 0;})->to_array() produces the array [1, 3, 5].
Returns a new generator that yields only the column with the $column_key key from what the current generator yields, considering that every item yielded is an array. Lazy/Fluent
Please note that, since we are interested in just a column, this method does NOT yield an array with one element, it yields the desired column value directly. The key information is lost.
Example: \LFF7\from_array([1, 2], [3, 4], [5, 6]])->column(0)->to_array() produces the array [1, 3, 5].
Returns a new generator that yields only the columns with the keys given in $column_keys from what the current generator yields, considering that every item yielded is an array. Lazy/Fluent
Key information is preserved.
Example: \LFF7\from_array([1, 2, 7], [3, 4, 8], [5, 6, 9]])->columns(1, 2)->to_array() produces the array [1=>2, 2=>7], [1=>4, 2=>8], [1=>6, 2=>9]].
Returns a new generator that removes the values having the $column_keys elements from what the current generator yields, considering that every item yielded is an array. Lazy/Fluent
For the elements that are left in the array, key information is preserved.