Appending a dictionary to csv file

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Appending a dictionary to csv file - zahra_vaziri - Apr-14-2020

Hi,

In a for loop I initially have the following dictionary:

dict1={'a':[[1,2],[3,4],[5,6]],'b':[[11,22],[33,44],[55,66]],'c':[[111,222],[333,444],[555,666]]}

I want to write it to a csv file as such:

Output:[1,2],[3,4],[5,6]
[11,22],[33,44],[55,66]
[111,222],[333,444],[555,666]

In the next iteration of the loop dict1 becomes:

dict1={'a':[[7,8],[9,10]],'b':[[77,88],[99,100]],'c':[[777,888],[999,1000]]

and I want to append this to the previous csv file as such:

Output:[1,2],[3,4],[5,6],[7,8],[9,10]
[11,22],[33,44],[55,66],[77,88],[99,100]
[111,222],[333,444],[555,666],[777,888],[999,1000]

I currently have this code:

if len(dict1)!=0:
    with open('dict1.csv', 'a+', encoding='utf8', newline='') as f:
         fc = csv.DictWriter(f, fieldnames=dict1.keys())
         fc.writerows(dict1)

This result in the following error:

Error:Traceback (most recent call last):
  File "Gain_readDataT.py", line 279, in signalGain
    fc.writerows(dict1)
  File "/usr/lib/python3.6/csv.py", line 158, in writerows
    return self.writer.writerows(map(self._dict_to_list, rowdicts))
  File "/usr/lib/python3.6/csv.py", line 148, in _dict_to_list
    wrong_fields = rowdict.keys() - self.fieldnames
AttributeError: 'str' object has no attribute 'keys'

Any ideas how I might do this correctly?