Xml to Csv Python Code too long
Optimization and restructuring

Redundant and inefficient things
The getvalueofnode function is unneeded: text attribute of a node will be None or string value. All intermediate dataframes are also unnecessary.Avoid using pd.Dataframe.append method within any loop as it will create a copy of accumulated dataframe of each loop iteration.

Namings
Use a meaningful names for your functions and if __name__ == '__main__': guard.I would suggest phones_to_df function name.



Assuming that the goal is to convert all Phones tags child nodes into dataframe records - all you need is collect a dictionaries of child nodes as &lt;el.tag: el.text&gt; mappings at once (+ special case for nuk tag, see below).Note, that some Phones tags could have their children in different order. So a list of dictionaries provides a robust way to arrange columns to respective values.

See the concise optimized approach below:

import xml.etree.cElementTree as cET
import pandas as pd


def phones_to_df(fname):
    tree = cET.parse(fname)
    pd.DataFrame([{**{el.tag: el.text for el in list(phone)},
                   **{f'nuk_{k}': v for k, v in phone.find('nuk').items()}}
                  for phone in tree.iterfind('Phones')]).to_csv('export.csv', index=False)


if __name__ == '__main__':
    phones_to_df(fname="test.xml")




After generating the expected export.csv file the resulting sample dataframe may look as below (I've tested on xml file with 2 Phones tags):

print(pd.read_csv('export.csv').to_string())

   Date  Prog  Box  Feature     WIN     Set     Pr     Number Simple  Nr          gt  Reno    QW  ER  VR  Use    Dar  age     name1            Sys         aac   time             nuk           nuk_name nuk_text_g  nuk_text_h
0   NaN   NaN  NaN      NaN  MAFWDS  234234  23423  afasfhrtv  dfasd NaN  6070106091  1233  3234 NaN NaN  NaN  sdfsd  NaN  sdfsfdfs  IVECO E.A.SY.  2019-05-29  02:00  fsdfsfd3432fdf  This is some text   asadsdas           2
1   NaN   NaN  NaN      NaN    ABCD     123    456        aaa    bbb NaN        1111   222   333 NaN NaN  NaN    rrr  NaN      wwww  TIMES E.A.SY.  2019-12-29  03:00        text ...  This is some text   asadsdas           2