This project tries to implement C# .NET lambda expressions in PHP.

Status

In development, semi-stable API.

Composer

Packagegist

composer require perryflynn/perrys-lambda

Features

• Implements many C# .NET like lambda expressions
• Support for auto conversion of records in custom objects
• Support for iteation and foreach
• Support for generator (helps with call-by-reference in loops)
• Helper classes for filesystem access
• Helper classes for CSV file parsing

Lambda methods

Method	Description
*OrDefault	Define return value if expression has no hit, available for many methods
first	Get the first record
last	Get the last record
single	Get the single record, if count!=0, throw exception
take	Get the first X records
skip	Skip the first X records
where	Filter records by callable expression
whereFirst	Get first record matching the callable expression
groupby	Group records by callable expression
distrinct	Eliminate duplicate records bei callable expression
intersect	Returns the intersection of two ArrayList's
except	Returns the bidirectional diffrence of two ArrayList's
any	Returns true if callable expression returns at least one record true
all	Returns true if callable expression returns for all records true
select	Get an array of the values returned by callable expression
selectMany	Get an array of all values, arrays will be merged
joinString	Join a string from values returned by callable expression
each	Execute callable expression on each record
sum	Get the sum of numberic return values from callable expression
min	Get the smallest of numberic return values from callable expression
max	Get the biggest of numberic return values from callable expression
avg	Get the average of numberic return values from callable expression
order	Start sorting, begin ascending, more possible by thenBy / thenByDesc
orderDesc	Start sorting, begin descending, more possible by thenBy / thenByDesc

Basic usage

$basic = new \PerrysLambda\ArrayList(array(1,2,3,4,5,6,7,8,9));

$basic->where(function($n) { return $n<=3; }); // Returns ArrayList of [1,2,3]
$basic->where(function($n) { return $n<=3; })->sum(); // Returns 6

Basic usage with ObjectArray and Strings instead of callables

$data = array(
    array('name'=>'Frank', age=>12),
    array('name'=>'Gene', age=>42),
    array('name'=>'Jessie', age=>31),
    array('name'=>'Carl', age=>55),
);

$list = \PerrysLambda\ArrayList::asObjectArray($data);
$list->select('age')->sum(); // Returns 140
$list->where(function($v) { return $v->age > 40; })->select('age')->sum(); // Returns 97

Deserialize / Serialize

• Deserialize json data
• Modify data
• Serialize again into json data
• Display modified json data

// examples/serialize.php

use PerrysLambda\ArrayList;
use PerrysLambda\ObjectArray;
use PerrysLambda\IArrayable;
use PerrysLambda\Converter\ItemConverter;
use PerrysLambda\Serializer\Serializer;
use PerrysLambda\Serializer\DateTimeSerializer;
use PerrysLambda\Serializer\BooleanSerializer;
use PerrysLambda\Converter\ListConverter;

// Testdata
$rawstring = <<<HEREDOC
{"foo":419995191,"bar":1492275950.5668,"foobar":"true","barfoo":"2018-12-08T20:24:41+0100","test":"Ivan"}
{"foo":92059366,"bar":1492275950.5669,"foobar":"false","barfoo":"2021-04-11T04:16:27+0200","test":"Gadget"}
{"foo":174207424,"bar":1492275950.5671,"foobar":"true","barfoo":"2017-07-29T21:53:36+0200","test":"Timmy"}
{"foo":624519809,"bar":1492275950.5672,"foobar":"false","barfoo":"2018-06-23T20:22:49+0200","test":"Alice"}
HEREDOC;

// Split into lines
$rawlines = explode("\n", $rawstring);

// Parse lines to one array with fields per line
$deserializer = function(&$row, &$key)
{
    if(is_string($row))
    {
        $data = json_decode($row, true);
        if(is_array($data))
        {
            $row = new ObjectArray($data);
        }
        else
        {
            return false;
        }
    }
    return true;
};

$serializer = function(&$row, &$key)
{
    if($row instanceof IArrayable)
    {
        $row = $row->toArray();
    }

    if(is_array($row))
    {
        $row = json_encode($row);
        if(is_string($row))
        {
            return true;
        }
    }
    return false;
};

// Row serializer
$fieldconverter = new ItemConverter();
$fieldconverter->setSerializer(new Serializer($serializer, $deserializer));

// Field serializer
$fieldconverter->setFieldSerializers(array(
    "barfoo" => DateTimeSerializer::fromIsoFormat(),
    "foobar" => new BooleanSerializer(),
));

// Create converter
$conv = new ListConverter();
$conv->setItemConverter($fieldconverter);
$conv->setArraySource($rawlines);

// Load raw data into ArrayList
$list = new ArrayList($conv);

// Modify data
$list
    ->where(function($v) { return $v->foobar===true; })
    ->each(function($v) { $v->foo = $v->foo+1; });

// Serialize modified data
$serlines = $list->serialize();
var_dump($serlines);

More examples

See the unit tests