There is no much difference between the Java/Python/JavaScript used in the KNIME snippets compared to the one used in other environments, so classic tutorials on Java/Python/etc. from the web would be useful to start with. The only thing different you need to know is how to gather the data and how to return the results.
Most often I learn this by looking at simple examples in the KNIME forum or in the hub. One thing I really love about the KNIME web site is that is full of examples associated to every node. For instance, if you need to know how to program in Python with the Python Script node, good places to look at are the following:
- Python Script Node Knime Hub web site.
- Python Script Node NodePit web site.
You’ll find there explanations and a list of workflows as examples:
or
Be aware that some of the scripting nodes come already along with examples called templates, to illustrate how the data need be gathered and returned:
These are just some hints to start with.
Best wishes,
Ael