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I want to read the file f in chunks to a dataframe. Here is part of a code that I used.

for i in range(0, maxline, chunksize):
df = pandas.read_csv(f,sep=',', nrows=chunksize, skiprows=i)
df.to_sql(member, engine, if_exists='append',index= False, index_label=None, chunksize=chunksize)

I get the error:

pandas.io.common.EmptyDataError: No columns to parse from file

The code works only when the chunksize >= maxline (which is total lines in file f). However, in my case, the chunksize<=maxline.

Please advise the fix.

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I think it is better to use the parameter chunksize in read_csv. Also, use concat with the parameter ignore_index, because of the need to avoid duplicates in index:

chunksize = 5
TextFileReader = pd.read_csv(f, chunksize=chunksize)

df = pd.concat(TextFileReader, ignore_index=True)

See pandas docs.

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5 Comments

Thanks! Now I get df as TextFileReader. The next step of my code demands df to be a dataframe. How can I convert TextFileReader to dataframe?
My actual data is about 85GB. Wouldn't concatenation make the datafram big? I want to use chunksize to read and write in chunks. Please advise.
Yes, it will be very big. Maybe you can check question.
That looks very difficult for a novice like me. "df = pandas.read_csv(f,sep=',', nrows=chunksize, skiprows=i)" actually gives dataframe. Can't this be modified to solve my problem. Updated the question. Thanks!
I use your solution some time ago and I get same error. Unfortunately I never use to_sql, so I cant help you with it.

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