HOST Function
Finds the host value from a valid URL. Input values must be of URL or String type and can be literals or column references.
In this implementation, a host value includes everything from the end of the protocol identifier (if present) to the end of the extension (e.g. .com).
For more information, seeStructure of a URL.
Wrangle vs. SQL: This function is part of Wrangle, a proprietary data transformation language. Wrangle is not SQL. For more information, see Wrangle Language.
Basic Usage
URL literal examples:
host('<span class="nolink">http://www.example.com</span>')
Output: Returns the value www.example.com.
Column reference example:
host(myURLs)
Output: Returns the host values extracted from the myURLs column.
Syntax and Arguments
host(column_url)
Argument | Required? | Data Type | Description |
|---|---|---|---|
column_url | Y | string | Name of column or String or URL literal containing the host value to extract |
For more information on syntax standards, see Language Documentation Syntax Notes.
column_url
Name of the column or URL or String literal whose values are used to extract the host value.
Missing input values generate missing results.
Multiple columns and wildcards are not supported.
Usage Notes:
Required? | Data Type | Example Value |
|---|---|---|
Yes | String literal or column reference (URL) | http://www.example.com |
Examples
Tip
For additional examples, see Common Tasks.
Example - Domain, Host, Subdomain, and Suffix functions
This examples illustrates how you can extract component parts of a URL using the following functions:
DOMAIN- extracts the domain value from a URL. See DOMAIN Function.SUBDOMAIN- extracts the first group after the protocol identifier and before the domain value. See SUBDOMAIN Function.HOST- returns the complete value of the host from an URL. See HOST Function.SUFFIX- extracts the suffix of a URL. See SUFFIX Function.URLPARAMS- extracts the query parameters and values from a URL. See URLPARAMS Function.FILTEROBJECT- filters an Object value to show only the elements for a specified key. See FILTEROBJECT Function.
Source:
Your dataset includes the following values for URLs:
URL |
|---|
www.example.com |
example.com/support |
http://www.example.com/products/ |
http://1.2.3.4 |
https://www.example.com/free-download |
https://www.example.com/about-us/careers |
www.app.example.com |
www.some.app.example.com |
some.app.example.com |
some.example.com |
example.com |
http://www.example.com?q1=broken%20record |
http://www.example.com?query=khakis&app=pants |
http://www.example.com?q1=broken%20record&q2=broken%20tape&q3=broken%20wrist |
Transformation:
When the above data is imported into the application, the column is recognized as a URL. All values are registered as valid, even the IPv4 address.
To extract the domain and subdomain values:
Transformation Name |
|
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | DOMAIN(URL) |
Parameter: New column name | 'domain_URL' |
Transformation Name |
|
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | SUBDOMAIN(URL) |
Parameter: New column name | 'subdomain_URL' |
Transformation Name |
|
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | HOST(URL) |
Parameter: New column name | 'host_URL' |
Transformation Name |
|
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | SUFFIX(URL) |
Parameter: New column name | 'suffix_URL' |
You can use the Wrangle in the following transformation to extract protocol identifiers, if present, into a new column:
Transformation Name |
|
|---|---|
Parameter: Column to extract from | URL |
Parameter: Option | Custom text or pattern |
Parameter: Text to extract | `{start}%*://` |
To clean this up, you might want to rename the column to protocol_URL.
To extract the path values, you can use the following regular expression:
Note
Regular expressions are considered a developer-level method for pattern matching. Please use them with caution. See Text Matching.
Transformation Name |
|
|---|---|
Parameter: Column to extract from | URL |
Parameter: Option | Custom text or pattern |
Parameter: Text to extract | /[^*:\/\/]\/.*$/ |
The above transformation grabs a little too much of the URL. If you rename the column to path_URL, you can use the following regular expression to clean it up:
Transformation Name |
|
|---|---|
Parameter: Column to extract from | URL |
Parameter: Option | Custom text or pattern |
Parameter: Text to extract | /[!^\/].*$/ |
Delete the path_URL column and rename the path_URL1 column to the deleted one. Then:
Transformation Name |
|
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | URLPARAMS(URL) |
Parameter: New column name | 'urlParams' |
If you wanted to just see the values for the q1 parameter, you could add the following:
Transformation Name |
|
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | FILTEROBJECT(urlParams,'q1') |
Parameter: New column name | 'urlParam_q1' |
Results:
For display purposes, the results table has been broken down into separate sets of columns.
Column set 1:
URL | host_URL | path_URL |
|---|---|---|
www.example.com | www.example.com | |
example.com/support | example.com | /support |
http://www.example.com/products/ | www.example.com | /products/ |
http://1.2.3.4 | 1.2.3.4 | |
https://www.example.com/free-download | www.example.com | /free-download |
https://www.example.com/about-us/careers | www.example.com | /about-us/careers |
www.app.example.com | www.app.example.com | |
www.some.app.example.com | www.some.app.example.com | |
some.app.example.com | some.app.example.com | |
some.example.com | some.example.com | |
example.com | example.com | |
http://www.example.com?q1=broken%20record | www.example.com | |
http://www.example.com?query=khakis&app=pants | www.example.com | |
http://www.example.com?q1=broken%20record&q2=broken%20tape&q3=broken%20wrist | www.example.com |
Column set 2:
URL | protocol_URL | subdomain_URL | domain_URL | suffix_URL |
|---|---|---|---|---|
www.example.com | www | example | com | |
example.com/support | example | com | ||
http://www.example.com/products/ | http:// | www | example | com |
http://1.2.3.4 | http:// | |||
https://www.example.com/free-download | https:// | www | example | com |
https://www.example.com/about-us/careers | https:// | www | example | com |
www.app.example.com | www.app | example | com | |
www.some.app.example.com | www.some.app | example | com | |
some.app.example.com | some.app | example | com | |
some.example.com | some | example | com | |
example.com | example | com | ||
http://www.example.com?q1=broken%20record | http:// | www | example | com |
http://www.example.com?query=khakis&app=pants | http:// | www | example | com |
http://www.example.com?q1=broken%20record&q2=broken%20tape&q3=broken%20wrist | http:// | www | example | com |
Column set 3:
URL | urlParams | urlParam_q1 |
|---|---|---|
www.example.com | ||
example.com/support | ||
http://www.example.com/products/ | ||
http://1.2.3.4 | ||
https://www.example.com/free-download | ||
https://www.example.com/about-us/careers | ||
www.app.example.com | ||
www.some.app.example.com | ||
some.app.example.com | ||
some.example.com | ||
example.com | ||
http://www.example.com?q1=broken%20record | {"q1":"broken record"} | {"q1":"broken record"} |
http://www.example.com?query=khakis&app=pants | {"query":"khakis","app":"pants"} | |
http://www.example.com?q1=broken%20record&q2=broken%20tape&q3=broken%20wrist | {"q1":"broken record", "q2":"broken tape", "q3":"broken wrist"} | {"q1":"broken record"} |