Add size as a product attribute

Add a product's size as a taxonomy attribute making it possible to filter a product list based on its size.

In this article

Example of a size filter

Add size attribute

Before you begin, the Size attribute must exist. To add it, go here WordPress Admin Area > Products > Attributes and add Size in the "Name" field and size in the "Slug" field.

Add 'Size' as an attribute

Use a single field for attribute

In this example, we will choose one field from the product's list of fields and store that field as the size attribute.

1

Identify the field

We can view all fields by clicking a product's name on the add/edit Product Sets pages in your WordPress Admin Area. We see that this product does have a "size" field so we will use that.

Example of a product's size field
2

Create a custom plugin

If you haven't done so already, create a custom plugin.

3

Add custom code

Add the following code to your custom plugin file.

/**
 * Add size attribute.
 *
 * The attribute "Size" with a slug of "size" must already exist here:
 * WordPress Admin Area > Products > Attributes.
 */
add_filter( 'dfrpswc_filter_attribute_value', 'mycode_add_size_attribute', 20, 6 );
function mycode_add_size_attribute( $value, $attribute, $post, $product, $set, $action ) {
	if ( $attribute == 'pa_size' ) {
		if ( isset( $product['size'] ) ) {
			$value = $product['size'];
		}
	}

	return $value;
}
	
4

Add/Update product sets

These changes will only take effect after any new Product Sets are created or after existing Product Sets are updated.

5

Expose filter as widget

Go here WordPress Admin Area > Appearance > Widgets and add a WooCommerce Layered Nav widget to your sidebar and configure it to display the size attribute like this:

Add size widget

Use multiple fields for attribute

Sometimes merchants store product information in different fields than other merchants. For example, some merchants will store the product's size in the "size" field while others will use a different field. In this example, we will use multiple fields to get the product's size.

1

Identify the fields

We can view all fields by clicking a product's name on the add/edit Product Sets pages in your WordPress Admin Area. We see that this product does not have a "size" field however it does have a field named "custom1" which contains the product's size. So we will use that field if the "size" field does not exist.

Product without a size field
2

Create a custom plugin

If you haven't done so already, create a custom plugin.

3

Add custom code

Add the following code to your custom plugin file.

/**
 * Add size attribute.
 *
 * The attribute "Size" with a slug of "size" must already exist here:
 * WordPress Admin Area > Products > Attributes.
 */
add_filter( 'dfrpswc_filter_attribute_value', 'mycode_add_size_attribute', 20, 6 );
function mycode_add_size_attribute( $value, $attribute, $post, $product, $set, $action ) {
	if ( $attribute == 'pa_size' ) {
		if ( isset( $product['size'] ) ) {
			$value = $product['size'];
		} elseif ( isset( $product['custom1'] ) ) {
			$value = $product['custom1'];
		}
	}

	return $value;
}
	
4

Add/Update product sets

These changes will only take effect after any new Product Sets are created or after existing Product Sets are updated.

5

Expose filter as widget

Go here WordPress Admin Area > Appearance > Widgets and add a WooCommerce Layered Nav widget to your sidebar and configure it to display the size attribute like this:

Add size widget

Use controlled vocabulary with one field

In the above examples, we rely on the names the merchants have provided for their product sizes. But this can sometimes lead to unexpected results like this:

Size names not using a controlled vocabulary.

In this example, we will provide a controlled vocabulary to ensure we have an organized size attribute filter.

Before and after using a controlled vocabulary.
1

Identify the field

We can view all fields by clicking a product's name on the add/edit Product Sets pages in your WordPress Admin Area. We see that this product does have a "size" field so we will use that.

Example of a product's size field
2

Create a custom plugin

If you haven't done so already, create a custom plugin.

3

Add custom code

Add the following code to your custom plugin file.

/**
 * Add size attribute.
 *
 * The attribute "Size" with a slug of "size" must already exist here:
 * WordPress Admin Area > Products > Attributes.
 */
add_filter( 'dfrpswc_filter_attribute_value', 'mycode_add_size_attribute', 20, 6 );
function mycode_add_size_attribute( $value, $attribute, $post, $product, $set, $action ) {
	if ( $attribute == 'pa_size' ) {
		if ( isset( $product['size'] ) ) {
			$value = mycode_get_size( $product['size'] );
		}
	}

	return $value;
}

/**
 * Normalize size attribute names.
 *
 * This returns a normalized value of a term based on a supplied
 * array of mappings of a key (desired word) mapped to an array of
 * keywords (undesired words).
 */
function mycode_get_size( $field, $default = '' ) {

	// Initialize $map array.
	$map = array();


	// ++++++++++ Begin Editing Here ++++++++++

	// Small, Medium, Large Sizes
	$map["XXXS"]   = array( "xxx small" );
	$map["XXS"]    = array( "xx small" );
	$map["XS"]     = array( "x small" );
	$map["Small"]  = array( "sm", "s" );
	$map["Medium"] = array( "md", "med", "m" );
	$map["Large"]  = array( "lg", "l" );
	$map["XL"]     = array( "extra large", "x large" );
	$map["XXL"]    = array( "xx large" );
	$map["XXXL"]   = array( "xxx large" );

	// European Shoe Sizes
	$map["34"]   = array( "34", "UK 2" );
	$map["34.5"] = array( "34.5", "UK 2" );
	$map["35"]   = array( "35", "UK 2.5" );
	$map["35.5"] = array( "35.5", "UK 3" );
	$map["36"]   = array( "36", "UK 3.5" );
	$map["36.5"] = array( "36.5", "UK 3.5" );
	$map["37"]   = array( "37", "UK 4" );
	$map["37.5"] = array( "37.5", "UK 4.5" );
	$map["38"]   = array( "38", "UK 5" );
	$map["38.5"] = array( "38.5", "UK 5.5" );
	$map["39"]   = array( "39", "UK 6" );
	$map["39.5"] = array( "39.5", "UK 6.5" );
	$map["40"]   = array( "40", "UK 7" );
	$map["40.5"] = array( "40.5", "UK 7" );
	$map["41"]   = array( "41", "UK 7.5" );
	$map["41.5"] = array( "41.5", "UK 7.5" );
	$map["42"]   = array( "42", "UK 8" );
	$map["42.5"] = array( "42.5", "UK 8.5" );
	$map["43"]   = array( "43", "UK 9" );
	$map["43.5"] = array( "43.5", "UK 9" );
	$map["44"]   = array( "44", "UK 9.5" );
	$map["44.5"] = array( "44.5", "UK 10" );
	$map["45"]   = array( "45", "UK 10.5" );
	$map["45.5"] = array( "45.5", "UK 10.5" );
	$map["46"]   = array( "46", "UK 11" );
	$map["46.5"] = array( "46.5", "UK 11.5" );
	$map["47"]   = array( "47", "UK 12" );


	// ++++++++++ Stop Editing Here ++++++++++


	// Initialize the $terms array.
	$terms = array();

	// Loop through $map, searching for $field in $map key or in $map keywords.
	foreach ( $map as $key => $keywords ) {

		// Add $key to $terms array if the $map key matches the field.
		if ( preg_match( '/\b' . preg_quote( $key, '/' ) . '\b/i', $field ) ) {
			$terms[] = $key;
		}

		// Add $key to $terms array if $field exists in array of keywords.
		foreach ( $keywords as $keyword ) {
			if ( preg_match( '/\b' . preg_quote( $keyword, '/' ) . '\b/i', $field ) ) {
				$terms[] = $key;
			}
		}
	}

	// If there are $terms, implode with WC_DELIMITER as separator.
	if ( ! empty( $terms ) ) {
		return implode( WC_DELIMITER, array_unique( $terms ) );
	}

	// No matches were found in $map for $field so return the $default value.
	return $default;
}
	

Notice we have provided a list of terms that should be associated with the main term (ie. size) that we want to use in our size filter.

4

Add/Update product sets

These changes will only take effect after any new Product Sets are created or after existing Product Sets are updated.

5

Expose filter as widget

Go here WordPress Admin Area > Appearance > Widgets and add a WooCommerce Layered Nav widget to your sidebar and configure it to display the size attribute like this:

Add size widget

Use controlled vocabulary with multiple fields

This is useful when a merchant provides the product's size in a field other than "size" or if a merchant only provides the size in the product's name. Using a controlled vocabulary on a variety of fields, we can extract the data we need!

1

Identify the fields

In this example, we will use 3 fields: size, custom1 and name in that order.

2

Create a custom plugin

If you haven't done so already, create a custom plugin.

3

Add custom code

Add the following code to your custom plugin file.

/**
 * Add size attribute.
 *
 * The attribute "Size" with a slug of "size" must already exist here:
 * WordPress Admin Area > Products > Attributes.
 */
add_filter( 'dfrpswc_filter_attribute_value', 'mycode_add_size_attribute', 20, 6 );
function mycode_add_size_attribute( $value, $attribute, $post, $product, $set, $action ) {
	if ( $attribute == 'pa_size' ) {
		if ( isset( $product['size'] ) ) {
			$value = mycode_get_size( $product['size'] );
		} elseif ( isset( $product['custom1'] ) ) {
			$value = mycode_get_size( $product['custom1'] );
		} elseif ( isset( $product['name'] ) ) {
			$value = mycode_get_size( $product['name'] );
		}
	}

	return $value;
}

/**
 * Normalize size attribute names.
 *
 * This returns a normalized value of a term based on a supplied
 * array of mappings of a key (desired word) mapped to an array of
 * keywords (undesired words).
 */
function mycode_get_size( $field, $default = '' ) {

	// Initialize $map array.
	$map = array();


	// ++++++++++ Begin Editing Here ++++++++++

	// Small, Medium, Large Sizes
	$map["XXXS"]   = array( "xxx small" );
	$map["XXS"]    = array( "xx small" );
	$map["XS"]     = array( "x small" );
	$map["Small"]  = array( "sm", "s" );
	$map["Medium"] = array( "md", "med", "m" );
	$map["Large"]  = array( "lg", "l" );
	$map["XL"]     = array( "extra large", "x large" );
	$map["XXL"]    = array( "xx large" );
	$map["XXXL"]   = array( "xxx large" );

	// European Shoe Sizes
	$map["34"]   = array( "34", "UK 2" );
	$map["34.5"] = array( "34.5", "UK 2" );
	$map["35"]   = array( "35", "UK 2.5" );
	$map["35.5"] = array( "35.5", "UK 3" );
	$map["36"]   = array( "36", "UK 3.5" );
	$map["36.5"] = array( "36.5", "UK 3.5" );
	$map["37"]   = array( "37", "UK 4" );
	$map["37.5"] = array( "37.5", "UK 4.5" );
	$map["38"]   = array( "38", "UK 5" );
	$map["38.5"] = array( "38.5", "UK 5.5" );
	$map["39"]   = array( "39", "UK 6" );
	$map["39.5"] = array( "39.5", "UK 6.5" );
	$map["40"]   = array( "40", "UK 7" );
	$map["40.5"] = array( "40.5", "UK 7" );
	$map["41"]   = array( "41", "UK 7.5" );
	$map["41.5"] = array( "41.5", "UK 7.5" );
	$map["42"]   = array( "42", "UK 8" );
	$map["42.5"] = array( "42.5", "UK 8.5" );
	$map["43"]   = array( "43", "UK 9" );
	$map["43.5"] = array( "43.5", "UK 9" );
	$map["44"]   = array( "44", "UK 9.5" );
	$map["44.5"] = array( "44.5", "UK 10" );
	$map["45"]   = array( "45", "UK 10.5" );
	$map["45.5"] = array( "45.5", "UK 10.5" );
	$map["46"]   = array( "46", "UK 11" );
	$map["46.5"] = array( "46.5", "UK 11.5" );
	$map["47"]   = array( "47", "UK 12" );


	// ++++++++++ Stop Editing Here ++++++++++


	// Initialize the $terms array.
	$terms = array();

	// Loop through $map, searching for $field in $map key or in $map keywords.
	foreach ( $map as $key => $keywords ) {

		// Add $key to $terms array if the $map key matches the field.
		if ( preg_match( '/\b' . preg_quote( $key, '/' ) . '\b/i', $field ) ) {
			$terms[] = $key;
		}

		// Add $key to $terms array if $field exists in array of keywords.
		foreach ( $keywords as $keyword ) {
			if ( preg_match( '/\b' . preg_quote( $keyword, '/' ) . '\b/i', $field ) ) {
				$terms[] = $key;
			}
		}
	}

	// If there are $terms, implode with WC_DELIMITER as separator.
	if ( ! empty( $terms ) ) {
		return implode( WC_DELIMITER, array_unique( $terms ) );
	}

	// No matches were found in $map for $field so return the $default value.
	return $default;
}
	
4

Add/Update product sets

These changes will only take effect after any new Product Sets are created or after existing Product Sets are updated.

5

Expose filter as widget

Go here WordPress Admin Area > Appearance > Widgets and add a WooCommerce Layered Nav widget to your sidebar and configure it to display the size attribute like this:

Add size widget

Provide default attribute value

When using the controlled vocabulary mentioned in the previous 2 examples you will see that if the size field doesn't contain a size in the controlled vocabulary you have configured, it will be ignored.

For example, if the product's size is XXXX Large, it will be ignored because we have not configured any controlled vocabulary for that term.

In these cases, we need to configure our code to either use the provided term (ie. XXXX Large) or we can provide a default value. in this example, we will force the script to use the value provided in the "size" or "custom1" fields if they exist, otherwise not use any value.

1

Identify the fields

In this example, we will use 3 fields: size, custom1 and name in that order.

2

Create a custom plugin

If you haven't done so already, create a custom plugin.

3

Add custom code

Add the following code to your custom plugin file.

/**
 * Add size attribute.
 *
 * The attribute "Size" with a slug of "size" must already exist here:
 * WordPress Admin Area > Products > Attributes.
 */
add_filter( 'dfrpswc_filter_attribute_value', 'mycode_add_size_attribute', 20, 6 );
function mycode_add_size_attribute( $value, $attribute, $post, $product, $set, $action ) {
	if ( $attribute == 'pa_size' ) {
		if ( isset( $product['size'] ) ) {
			$value = mycode_get_size( $product['size'], $product['size'] );
		} elseif ( isset( $product['custom1'] ) ) {
			$value = mycode_get_size( $product['custom1'], $product['custom1'] );
		} elseif ( isset( $product['name'] ) ) {
			$value = mycode_get_size( $product['name'] );
		}
	}

	return $value;
}


/**
 * Normalize size attribute names.
 *
 * This returns a normalized value of a term based on a supplied
 * array of mappings of a key (desired word) mapped to an array of
 * keywords (undesired words).
 */
function mycode_get_size( $field, $default = '' ) {

	// Initialize $map array.
	$map = array();


	// ++++++++++ Begin Editing Here ++++++++++

	// Small, Medium, Large Sizes
	$map["XXXS"]   = array( "xxx small" );
	$map["XXS"]    = array( "xx small" );
	$map["XS"]     = array( "x small" );
	$map["Small"]  = array( "sm", "s" );
	$map["Medium"] = array( "md", "med", "m" );
	$map["Large"]  = array( "lg", "l" );
	$map["XL"]     = array( "extra large", "x large" );
	$map["XXL"]    = array( "xx large" );
	$map["XXXL"]   = array( "xxx large" );

	// European Shoe Sizes
	$map["34"]   = array( "34", "UK 2" );
	$map["34.5"] = array( "34.5", "UK 2" );
	$map["35"]   = array( "35", "UK 2.5" );
	$map["35.5"] = array( "35.5", "UK 3" );
	$map["36"]   = array( "36", "UK 3.5" );
	$map["36.5"] = array( "36.5", "UK 3.5" );
	$map["37"]   = array( "37", "UK 4" );
	$map["37.5"] = array( "37.5", "UK 4.5" );
	$map["38"]   = array( "38", "UK 5" );
	$map["38.5"] = array( "38.5", "UK 5.5" );
	$map["39"]   = array( "39", "UK 6" );
	$map["39.5"] = array( "39.5", "UK 6.5" );
	$map["40"]   = array( "40", "UK 7" );
	$map["40.5"] = array( "40.5", "UK 7" );
	$map["41"]   = array( "41", "UK 7.5" );
	$map["41.5"] = array( "41.5", "UK 7.5" );
	$map["42"]   = array( "42", "UK 8" );
	$map["42.5"] = array( "42.5", "UK 8.5" );
	$map["43"]   = array( "43", "UK 9" );
	$map["43.5"] = array( "43.5", "UK 9" );
	$map["44"]   = array( "44", "UK 9.5" );
	$map["44.5"] = array( "44.5", "UK 10" );
	$map["45"]   = array( "45", "UK 10.5" );
	$map["45.5"] = array( "45.5", "UK 10.5" );
	$map["46"]   = array( "46", "UK 11" );
	$map["46.5"] = array( "46.5", "UK 11.5" );
	$map["47"]   = array( "47", "UK 12" );


	// ++++++++++ Stop Editing Here ++++++++++


	// Initialize the $terms array.
	$terms = array();

	// Loop through $map, searching for $field in $map key or in $map keywords.
	foreach ( $map as $key => $keywords ) {

		// Add $key to $terms array if the $map key matches the field.
		if ( preg_match( '/\b' . preg_quote( $key, '/' ) . '\b/i', $field ) ) {
			$terms[] = $key;
		}

		// Add $key to $terms array if $field exists in array of keywords.
		foreach ( $keywords as $keyword ) {
			if ( preg_match( '/\b' . preg_quote( $keyword, '/' ) . '\b/i', $field ) ) {
				$terms[] = $key;
			}
		}
	}

	// If there are $terms, implode with WC_DELIMITER as separator.
	if ( ! empty( $terms ) ) {
		return implode( WC_DELIMITER, array_unique( $terms ) );
	}

	// No matches were found in $map for $field so return the $default value.
	return $default;
}
	

Notice we are forcing the script to use the value provided by the merchant if there is no match in our controlled vocabulary. However we do not provide a default in line #16 as we do not want to store the product's name as a size attribute.

4

Add/Update product sets

These changes will only take effect after any new Product Sets are created or after existing Product Sets are updated.

5

Expose filter as widget

Go here WordPress Admin Area > Appearance > Widgets and add a WooCommerce Layered Nav widget to your sidebar and configure it to display the size attribute like this:

Add size widget

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