Pandas generate multiple CSV files on a loop

Question

I'm trying to recreate what I achieved manually using a for loop What I did was to manually written 10 CSV files. the code is like this

     df_1.to_csv('eblist1.csv', encoding='latin-1', index=False)
     df_2.to_csv('eblist2.csv', encoding='latin-1', index=False)
     df_3.to_csv('eblist3.csv', encoding='latin-1', index=False)
     df_4.to_csv('eblist4.csv', encoding='latin-1', index=False)
     df_5.to_csv('eblist5.csv', encoding='latin-1', index=False)
     df_6.to_csv('eblist6.csv', encoding='latin-1', index=False)
     df_7.to_csv('eblist7.csv', encoding='latin-1', index=False)
     df_8.to_csv('eblist8.csv', encoding='latin-1', index=False)
     df_9.to_csv('eblist9.csv', encoding='latin-1', index=False)
     df_10.to_csv('eblist10.csv', encoding='latin-1', index=False)

That works fine as expected it writes all these files from my dataframes. Then I tried to achieve the same thing using a loop ... and here is where I got stuck, I spent hours reading at different solutions, and tried several options, but I always end up getting a syntax error

     line 98, in <module>
names.to_csv('eblist'+str(res)+'.csv', encoding='latin-1', index=False)

     AttributeError: 'str' object has no attribute 'to_csv'

The only thing I need is a way to add the value to the string, as the loop iterates through the dictionary, and believe me, I tried many approaches ...

      d = {'df_1':df_1,'df_2': df_2,'df_3': df_3,'df_4': df_4,'df_5': 
      df_5,'df_6': df_6,'df_7': df_7,'df_8': df_8,'df_9': df_9,'df_10': 
      df_10}

      for names in d:
          res = list(d.keys()).index(names) 
          names.to_csv('eblist'+str(res)+'.csv', encoding='latin-1', index=False)

my guess is that you don't even need to have this many dataframes. they should all be in one dataframe with an identifying column and a bunch of groupby operations — Paul H
– Paul H, Commented Feb 13, 2021 at 1:21

Bobby Ocean · Accepted Answer · 2021-02-13 01:09:47Z

1

Based on the error message "'str' object has no attribute 'to_csv'", it appears you attempted to access the to_csv() method from a string and not the class itself. You are on the right track. Assuming you have a list of your dataframes (the actual dataframes and not strings of the dataframes), then you should be able to do what you are looking for:

  dfs = [df_1, df_2, df_3, df_4, df_5, df_6, df_7, df_8, df_9, df_10]

  for index,df in enumerate(dfs,1):
      df.to_csv(f'eblist{index}.csv', encoding='latin-1', index=False)

edited Feb 13, 2021 at 1:09

answered Feb 13, 2021 at 0:23

Bobby Ocean

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4 Comments

Stefan B Over a year ago

improvement suggestion: enumerate(dfs, 1) to get rid of the index+1 clutter inside the loop-body?

Bobby Ocean Over a year ago

@StefanB Nice!!

user1871188 Over a year ago

@Bobby Ocean Thank you! My limited Python knowledge shows ;) ... I upvoted your answer, that should do the trick!

user1871188 Over a year ago

also thanks to @StefanB for improving it!

Valentino · Accepted Answer · 2021-02-13 02:38:23Z

0

AttributeError: 'str' object has no attribute 'to_csv'

This is due to your loop:

for names in d:

This is iterating over the keys of your dictionary, which are strings. You actually never access to the values of your dictionary (the dataframes). If you really want to use a dictionary, just do:

for names, df in d.items():
    res = list(d.keys()).index(names) 
    df.to_csv('eblist'+str(res)+'.csv', encoding='latin-1', index=False)

Or better use a list instead of a dictionary as suggested in other answers, since it seems that you are interested in the position and the keys do not have any other meaning.

answered Feb 13, 2021 at 2:38

Valentino

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