Python

The Python action runs a piece of Python code that you write, as one step of your process. Use it for calculations, data clean-up or text processing that no ready-made action covers. The value your code returns becomes an output you can use in the next steps.

Add the action

In the Process Designer toolbox, open Scripting and pick Python (or type Python in the search box).

Inputs and outputs

How your code is run

Your code runs as the body of a function:

• return <value> ends the code and sends the value to Single Result, or to List Result when the value is a list. Only one of the two is filled.
• print() does not set a result. What you print goes to Stdout, which is useful for checking what your code did.
• Code that ends without return leaves both results empty.

Examples

You can define functions and call them:

def add(a, b):
    return a + b

print('adding')
return add(2, 3)

Result: Single Result 5, Stdout adding.

A library example:

import pandas as pd
return int(pd.Series([1, 2, 3]).sum())

Result: Single Result 6.

Use process variables in the code

You can insert process variables into the code. Before the code runs, PROCESIO replaces each variable with its value, as plain text. So:

• a number variable can be used as it is: total = <your number variable> * 2;
• a text variable needs quotes around it in your code: name = "<your text variable>".

Good to know

• A failing script does not stop the process. When your code raises an error or runs longer than Timeout, the step still finishes: Error holds the message (TimeoutError for a timeout) and both results are empty. Add a Decisional after the action that checks whether Error is empty.
• The code runs in a sandbox. It cannot read or write files (open is not available) and some modules cannot be imported, for example os or requests; the error then says import of '…' is not allowed in this sandbox. To call a web API, use Call API or CURL and pass the response to the script.
• Files: a script cannot take a file directly. Convert the file to text with File To Base64, pass the text to the script and decode it there with base64. To create a file from a script, return Base64 text and convert it with Base64 To File.
• Heavy libraries such as pandas take a few seconds to load. Keep Timeout well above the time your code needs.

Available libraries

Besides the standard modules such as json, base64, math, re and datetime, these libraries are installed:

Related actions

• Node, Ruby, Javascript, CURL
• File To Base64, Base64 To File