getting values from xml error: AttributeError: 'NoneType' object has no attribute 'text'

Question

I am getting some json from an api, and with the json response i am writing the data to a csv file. some of the json keys are numbers(actually strings but can be converted) and some of them are strings. If they are numbers I need to convert them to an actual name. I have an xml file as a look up table of sort and I am getting some errors on getting the text from a xml field.

.json file

[
    {
    "id": "228",
    "fullName2": "users name",
    "4600.0": "0000-00-00",
    "4600.2": "some text",
    }
]

columnLookup.xml file as a look up table

<data>
 <fields>
   <field id="NA" alias="fullName2">full name</field>
   <field id="15493" alias="id">id</field>
   <field id="4600.0" alias="jobTitle">Job Title</field>
 </fields>
</data>

.py file Mycode

def write_to_csv_file(self):
        with open(self.mJSON_file_name) as json_file:
            data = json.load(json_file)

            csv_file = open(self.mCSV_file_name, 'w')

            csv_writer = csv.writer(csv_file)
            count = 0
            keys_dict = {}
            for emp in data:
                if count == 0:
                    header = emp.keys()
                    for key in header:
                        headers = get_name_from_id(key)
                        keys_dict[headers] = ''
                    
                    csv_writer.writerow(keys_dict.keys())
                    count += 1
                csv_writer.writerow(emp.values())
        
        csv_file.close()
        self.mCSV_data = csv_file

def get_name_from_id( search_id):
    query = 'field[@id="{}"]'.format(search_id)
    alias_query = 'field[@alias="{}"]'.format(search_id)

    tree = ET.parse('columnLookup.xml')
    root = tree.getroot()

    for data in root.iter('fields'):
        if search_id.isdigit():
            return data.find(query).text
        else:
            return data.find(alias_query).text

explenation:

basically I get that key from the json file and pass it to the get_name_from_id() function. if it can be converted to a digit. I look up the id of the value in the xml file and return the text. If it cant be converted to a digit, then I look up the text value from the alias of a field. im crashing on "fullName2".

when the key from the json file is "fullName2", I need it to find the field in the xml file with alias="fullName2" and then return the text "full name". any ideas why im getting the attribute error?

Try query = '//field[@id="{}"]'.format(search_id) that is a relative path lookup. — LMC
– LMC, Commented Jul 22, 2021 at 21:42
always put full error message (starting at word "Traceback") in question (not comment) as text (not screenshot, not link to external portal). There are other useful information. — furas
– furas, Commented Jul 22, 2021 at 23:48
error meas that it couldn't fine element so you get None and try to do None.text. First you should get item = data.find(query) and item = data.find(alias_query) and check if itme is not None and then use return item.text. — furas
– furas, Commented Jul 22, 2021 at 23:49
your for-loop is wrong - you have return in if and else so it exits function on first element fields. — furas
– furas, Commented Jul 22, 2021 at 23:53
@LMC I think it would need also dot at start - './/field[@id="{}"]' - to make it relative to data — furas
– furas, Commented Jul 22, 2021 at 23:56

furas · Accepted Answer · 2021-07-23 01:51:05Z

I tried create minimal working code with data directly in code and I found problem makes isdigit() which checks only if there are digits in string - not if this is string with integer or float - so "4600.0".isdigit() gives False and it searchs it in alias instead of id.

You shouldn't use isdigit but check both xpath and if one of them gives node then return `text

for data in root.iter('fields'):
    if data.find(query):
        return data.find(query).text
    if data.find(alias_query):
        return data.find(alias_query).text

Other problem can be that you not use relative xpath so it search in wrong place.

query = './/field[@id="{}"]'.format(search_id)
alias_query = './/field[@alias="{}"]'.format(search_id)

Minimal working code

text_json ='''[
    {
    "id": "228",
    "fullName2": "users name",
    "4600.0": "0000-00-00",
    "4600.2": "some text"
    }
]'''

text_xml = '''<data>
 <fields>
   <field id="NA" alias="fullName2">full name</field>
   <field id="15493" alias="id">id</field>
   <field id="4600.0" alias="jobTitle">Job Title</field>
 </fields>
</data>
'''

import json
import csv
import lxml.etree as ET

class Test():
        
    def write_to_csv_file(self):
        #with open(self.mJSON_file_name) as json_file:
        #    data = json.load(json_file)
        data = json.loads(text_json)
        
        #with open(self.mCSV_file_name, 'w') as csv_file:
        with open('output.csv', 'w') as csv_file:
            csv_writer = csv.writer(csv_file)
            
            header_added = False
            
            for row in data:
                if not header_added:
                    headers = []
                    for key in row.keys():
                        name = get_name_from_id(key)
                        headers.append(name)
                    csv_writer.writerow(headers)
                    header_added = True
            
                csv_writer.writerow(row.values())
        
        #self.mCSV_data = csv_file

# ----

# read it only once

root = ET.fromstring(text_xml)
#tree = ET.parse('columnLookup.xml')
#root = tree.getroot()

def get_name_from_id(search_id):
    print('[get_name_from_id] search_id:', search_id)
    
    query_id    = './/field[@id="{}"]'.format(search_id)
    query_alias = './/field[@alias="{}"]'.format(search_id)
    
    for fields in root.iter('fields'):
        items = fields.xpath(query_alias)
        if items:
            print('query:', query_alias)
            print('items:', items)
            print('text:', items[0].text)
            return items[0].text
        items = fields.xpath(query_id)
        if items:
            print('query:', query_alias)
            print('items:', items)
            print('text:', items[0].text)
            return items[0].text
        
# --- main ---

t = Test()
t.write_to_csv_file()

LMC · Accepted Answer · 2021-07-23 00:23:49Z

1

Both attributes can be queried at the same time returning the first result. Assuming no duplicates and the search argument exists.

from lxml import etree
tree = etree.parse('test.xml')
arr = tree.xpath('//field[@id="{0}" or @alias="{0}"]'.format('15493'))
print(arr[0].text)
# result: id
arr = tree.xpath('//field[@id="{0}" or @alias="{0}"]'.format('fullName2'))
print(arr[0].text)
# result: full name
len(arr)
# result: 1
# the list contains 1 element

answered Jul 23, 2021 at 0:23

LMC

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