python - Why the object, which I read a csv file using pandas from, is TextFileReader object

Question

I read a csv file using pandas:

data_raw = pd.read_csv(filename, chunksize=chunksize)
print(data_raw['id'])

Then, it reports TypeError:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'TextFileReader' object has no attribute '__getitem__'

What can I do to resolve the problem? And how can I change the data_raw into a dataFrame object? I use the python2.7 and pandas v0.19.1

Answer 1

When you pass chunksize option to read_csv(), it creates a TextFileReader reader - an open-file-like object that can be used to read the original file in chunks. See usage example here: How to read a 6 GB csv file with pandas When this option is not provided, the function indeed reads the file content.