How to Add query strings to links in WordPress

This article describes how to add a query string to a link in WordPress by using the add_query_arg () function, you can refer to the query string after the question mark in the link. the format is key = value. Separate multiple query statements with the & symbol. The add_query_arg () function is a convenient function provided by WordPress. it can help you add one or more query statements to a link.

Someone may ask, can I add a query string directly after the link and manually append it? This is sometimes feasible, but if the link itself has a query string, it will cause format errors, and it is not conducive to PHP writing and management. the add_query_arg () function helps you think about everything, you only need to provide the link for adding the query string and one or more key values and key names.

Usage

add_query_arg( $key, $value, $old_query_or_uri );add_query_arg( $query, $old_query_or_uri );

Parameters

Add_query_arg () can be used in two ways. The first method requires three parameters.

$ Key

(Integer | string) (required) key value of the parameter to be added. like an array, if it is a string, it is the name, and the number is the nth parameter.

Default value: None

$ Value

(Mixed) (required) value to be added.

Default value: None

$ Old_query_or_uri

(String) (optional) link to be processed.

Default value: False. if it is set to False, the value is $ _ SERVER ['request _ URI '].

In the second method, two parameters are required to pass the query string to be added to the link using an array.

$ Query

(Array) (required) the query to be added. The key value corresponds to the key name.

Default value: None

$ Old_query_or_uri

(String) (optional) link to be processed.

Default value: False. if it is set to False, the value is $ _ SERVER ['request _ URI '].

Return value

(String) add the link to the query string.

Example

First usage:

echo add_query_arg( 'id', 123, 'http://www.bitsCN.com' );

Second usage:

echo add_query_arg( array( 'id' => 123 ), 'http://www.bitsCN.com' );

Are both results of http://www.bitsCN.com? Id = 123

Other special cases:

echo add_query_arg( array( 'id' => 123 ), 'http://www.bitsCN.com?query=post' );//http://www.bitsCN.com?query=post&id=123echo add_query_arg( array( 'id' => 123, 'cat' => 'themes' ), 'http://www.bitsCN.com?query=post' );//http://www.bitsCN.com?query=post&id=123&cat=themesecho add_query_arg( array( 'id' => 123, 'cat' => 'themes', 'query' => 'page' ), 'http://www.bitsCN.com?query=post' );//http://www.bitsCN.com?query=page&id=123&cat=themes

Example

This function is located in: wp-functions des/functions. php