lua_compute

Computing with a Lua Window

Overview

This example demonstrates how you can use Lua code to modify user data. The Lua window in this example serves as an alternative to a Compute window to enable a one-to-one transformation of input events to output events.

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NOTE: Use this example with SAS Event Stream Processing 2021.2.1 and later.

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For more information about how to install and use example projects, see Using the Examples.

Use Case

The model handles customer information for a telecommunications company. A Lua window called TransformData is configured to perform several actions:

• Capitalize each customer’s surname.
• Determine each customer’s preferred method of communication and save it to a new field, notify.
  • If the customer has a telephone number, then set the preferred method of communication to sms.
  • If the customer does not have a telephone number but does have an email address, then set the preferred method of communication to email.
• Convert each telephone number to a standard format by reading the final ten digits and removing all non-alphanumeric characters.

Source Data

The file lua_compute.csv contains customer information.

Workflow

The following figure shows the diagram of the project:

Customers

The Customers window streams customer information from the lua_compute.csv file to the TransformData window.

Explore the settings for the Customers window:

1. Open the project in SAS Event Stream Processing Studio and select the Customers window.
2. To examine the window's output schema, on the right toolbar, click . Observe the following fields:
   • custref: This is the customer reference ID. It is also selected as the Key.
   • forename: This is the customer’s first name.
   • surname: This is the customer’s last name.
   • telno: This is the customer’s telephone number.
   • email: This is the customer’s email address.
3. Click .

TransformData

The TransformData window is configured to perform several actions. For more information, see Use Case.

Explore the settings for this window:

1. Select the TransformData window in the workspace.

2. In the right pane, expand Lua Settings.

   • To increase the efficiency of the Lua code processing, you can specify which fields to copy from the source file and which fields to use in the Lua code. Note the following details in this example:
     • The Fields to copy field shows that the fields surname and telno are excluded. All other fields from the source file can be copied because they are not transformed by the Lua code.
     • The Fields to use in Lua code field shows that the fields surname and telno are included. These fields are transformed by the Lua code.
   • Observe that the Events function field shows the Lua function that is used (in this case, the create function).

3. Scroll down in the right pane, to view the Lua code that performs the calculations for this example:

   Step	Lua Code Section
   Read in the data from the lua_compute.csv file.	function create(data,context) local e = {}
   Capitalize each customer’s surname.	e.surname = string.upper(data.surname)
   Retain the final ten digits of each telephone number.	e.telno = cleanNumber(data.telno)
   If a customer has a telephone number, then assign the value sms.	if (e.telno ~= "") then local len = string.len(e.telno) if (len > 10) then e.telno = string.sub(e.telno,len - 10 + 1) end e.notify = "sms"
   Otherwise, if a customer does not have telephone number, then assign the value email.	else e.notify = "email" end return(e) end
   To bring the telephone numbers into a standardized format, remove all non-alphanumeric characters from each telephone number.	function cleanNumber(telno) local str = "" if (telno ~= "" and telno ~= nil) then str = "" for c in telno:gmatch("[0-9]") do str = str..c end end return(str) end

Test the Project and View the Results

When you test the project, the results for each window appear on separate tabs. The following figure shows the customer data in the Customers tab. Note the following details:

• Each customer’s surname is in title case.
• The telephone numbers were not entered using the same format.
• The customers Hermione Grandeur and Draco Molefay have no entry for telno.

The following figure shows the transformed data in the TransformData tab. Note the following changes:

• All surnames are now in all capital letters.
• Each telephone number shows ten digits with no spaces or non-numerical characters.
• A new variable, notify, has been created. Each customer with a telephone number has been assigned the value sms, whereas the customers without a telephone number (Hermione Grandeur and Draco Molefay) have been assigned the value email.

Additional Resources

For more information, see SAS Help Center: Using Lua Windows.