'NoneType' object is not iterable

print('The value of "d" is: ' + str(d))

@david_r 

will its a list of strings 

The value of "d" is: ['40QFM1818918004', '40QFM2615910278', '40QFM1322416717', '40QFM2059919336', '40QFM1539918653']

its very huge there a sample

The value of "d" is: ['40QFM1818918004', '40QFM2615910278', '40QFM1322416717', '40QFM2059919336', '40QFM1539918653']

I'm guessing you have more than one feature? Do they all have a list of values, or does one or several of them not have a list value? 

Before your Python code, try inserting a ListElementCounter on tag_list{}.TAG_ID, then a Tester to check that the count of elements > 0. If you have any elements where the count is 0, then there's the problem.

If your list has sub_elements it's possible for it to pass the ListElementCounter test whilst still not having a value for tag_list{}.TAG_ID depending on how the list has been built

If you want to find which features do not have any tag_list{}.TAG_ID values you could do the following in a python caller

import fme
import fmeobjects

class FeatureProcessor(object):
    def __init__(self):
        pass
    def input(self,feature):
        s = str(feature.getAttribute('partial'))
        d = feature.getAttribute('tag_list{}.TAG_ID')
        if d:
            pass
        else:
            self.pyoutput(feature)
    def close(self):
        pass

print('The value of "d" is: ' + str(d))

yeah sure here

i think the problem is that i put the list(coming from listbuilder) as input and the pythoncaller treating it as the firs input not something i need to use with each record

@ebygomm @david_r what should i do to make the list as a variable usable with every record in paythoncaller

Is it possible that your code is located under the "__init__" method (executed once at startup) rather than under the "input" method (executed once for every input feature)?

See the screenshot posted by @ebygomm below.

Can you please post a screenshot of the entire PythonCaller transformer configuration? Or even better, post a minimal sample workspace that demonstrates the problem.

This error means that python is trying to iterate over a None object. With Python, you can only iterate over an object if that object has a value. This is because iterable objects only have a next item which can be accessed if their value is not equal to None. If you try to iterate over a None object, you encounter the TypeError: ‘NoneType’ object is not iterable error.

For example, list.sort() only change the list but return None. 

Python's interpreter converted your code to pyc bytecode. The Python virtual machine processed the bytecode, it encountered a looping construct which said iterate over a variable containing None. The operation was performed by invoking the `__iter__` method on the None. None has no` __iter__` method defined, so Python's virtual machine tells you what it sees: that NoneType has no` __iter__` method.

Technically, you can avoid the NoneType exception by checking if a value is equal to None before you iterate over that value.

This error indicates an attempt to access an indexing functionality on an object that does not support it. Specifically, you are trying to subscript an object that you assume to be a list or dictionary, but it is actually None. NoneType is the type assigned to the None object, which signifies the absence of a value. For instance, a function that does not explicitly return a value will default to returning None. When you encounter the error message "'NoneType' object is not subscriptable," it means that you are using square bracket notation (object[key]) on an object that does not define the getitem method required for indexing.

A subscriptable object refers to any object that supports the getitem special method, such as lists or dictionaries. It is an object that can record and store operations performed on it as a "script" that can be replayed. However, in your case, you are attempting to subscript an object that you believe to be a list or dictionary, but it is actually None. NoneType is the type assigned to the None object, which signifies the absence of a value. For instance, when a function does not explicitly return a value, it defaults to returning None. When you encounter the error "'NoneType' object is not subscriptable," it means that you are using square bracket notation (object[key]) on an object that does not define the getitem method required for indexing. It is worth noting that certain methods, like sort(), which only modify a list, do not have a printed return value and instead return the default None. This is a design principle applied to all mutable data structures in Python.