Filter

Description

Compare values in objects against pre-set values in the filter. The filter is constructed from a string with a key (field name in the the object), operator and a value to be compared against. Then an object is passed to the filter and evaluated whether it passes the filter or not.

Usage

use Keboola\Filter\Filter;

// Compare the `shoeSize` property of John
$john = new \stdClass();
$john->shoeSize = 45;
$filter = FilterFactory::create("shoeSize>42");
$filter->compareObject($john); // true

// Multiple conditions can be used
$filter = FilterFactory::create("field1==0&field2!=0");
$object = (object) [
    'field1' => 0,
    'field2' => 1
];
$result = $filter->compareObject($object); // true

• The filter is whitespace sensitive, therefore value == 100 will look into value␣ for a ␣100 value, instead of value and 100 as likely desired.
• Correct use: value==100
• Wrong use: value == 100

Supported comparison operators

• < -- less than
• > -- greater than
• == -- equals
• <= -- less or equals
• >= -- greater or equals
• != -- not equals
• ~~ -- like
• !~ -- not like

Like operator

Like (and not like) operator allows you to use partial matching. Use a percent % character in the target value to match any number of characters, e.g.:

use Keboola\Filter\Filter;

// Compare the `shoeSize` property of John
$john = new \stdClass();
$john->name = "Johnny";
$filter = FilterFactory::create("name~~Johnny");
$filter->compareObject($john); // true

Supported logical operators

With logical operators you can combine multiple conditions together. You can combine both conditions with different values and conditions with different keys. Supported logical operators:

• & -- logical and
• | -- logical or

Usage

• Case 1: Object's status must be enabled and age must be over 18

status==enabled&age>18

{
    'status': 'enabled',
    'age': 20
}

compareObject on this object will return true.

{
    'status': 'enabled',
    'age': 15
}

compareObject on this object will return false.

• Case 2: Object's status must be new or udated

status==new|status==updated

{
    'status': 'new'
}

compareObject on this object will return true.

{
    'status': 'updated'
}

compareObject on this object will return true.

{
    'status': 'closed'
}

compareObject on this object will return false.

Combining logical operators

Parentheses are not supported, however the standard operator precedence is applied (& precedes |). For example, the expression a==b&c==d|e==f is interpreted as (a==b&c==d)|e==f and the
expression a==b&c==d|e==f&g==h translates into (a==b&c==d)|(e==f&g==h).