I have a text(ex: "a b cd" or "aa1 b c def") containing feq

doForEach can be used to process rules that have split function. For your use case, you can use the below expression rules -
A rule to get the last part after the space in your text -
rule!getLastPart
- index(split(ri!textValue,char(32)),length(split(ri!textValue,char(32))),"")
Here, rule input textValue is a single value Text input
You can now run doforeach on the above -
doforeach("rule!getLastPart", ri!arrayOfValues)
Here, arrayOfValues is the array of items that contains many such text as in your example.For each of the text elements, the rule will be executed.
If you are on version lower than 6.7, you can use doforeach. For 6.7 and above, you can use apply() instead as it is an out of the box function.

doForEach can be used to process rules that have split function. For your use case, you can use the below expression rules -
A rule to get the last part after the space in your text -
rule!getLastPart
- index(split(ri!textValue,char(32)),length(split(ri!textValue,char(32))),"")
Here, rule input textValue is a single value Text input
You can now run doforeach on the above -
doforeach("rule!getLastPart", ri!arrayOfValues)
Here, arrayOfValues is the array of items that contains many such text as in your example.For each of the text elements, the rule will be executed.
If you are on version lower than 6.7, you can use doforeach. For 6.7 and above, you can use apply() instead as it is an out of the box function.