How to add pandas data to an existing csv file?
You can append to a csv by opening the file in append mode:
with open('my_csv.csv', 'a') as f: df.to_csv(f, header=False)If this was your csv, foo.csv:
,A,B,C0,1,2,31,4,5,6If you read that and then append, for example, df + 6:
In [1]: df = pd.read_csv('foo.csv', index_col=0)In [2]: dfOut[2]: A B C0 1 2 31 4 5 6In [3]: df + 6Out[3]: A B C0 7 8 91 10 11 12In [4]: with open('foo.csv', 'a') as f: (df + 6).to_csv(f, header=False)foo.csv becomes:
,A,B,C0,1,2,31,4,5,60,7,8,91,10,11,12