How to read specific column index from csv using pandas

Question

Is there some way of reading only a particular column with specific index from a csv file using Pandas(preferably read_csv)? I understand that read_csv provides the ability to read specific columns by column names, but the data file has no headers so I cannot use column names. Note that the file is too large, so I do not want to read in the entire file and then subset. Thanks.

use_cols supports ordinal based indexing: use_cols=[1,4] will read only 2nd and 5th column — EdChum
– EdChum, Commented Sep 7, 2015 at 15:06
Just a 'for information' - you can't combine index and name e.g. use_cols = ['Name', 5, 'Date' does not work]. It returns an error 'ValueError: 'usecols' must either be all strings, all unicode, all integers or a callable'. — MrDave
– MrDave, Commented Mar 8, 2019 at 10:03

Romain · Accepted Answer · 2015-09-07 18:20:22Z

6

Here is an example illustrating the answer given by EdChum. There is a lot of additional options to load a CSV file, check the API reference.

raw_data = {'first_name': ['Steve', 'Guido', 'John'],
        'last_name': ['Jobs', 'Van Rossum', "von Neumann"]}
df = pd.DataFrame(raw_data)
# Saving data without header
df.to_csv(path_or_buf='test.csv', header=False)
# Telling that there is no header and loading only the first name
df = pd.read_csv(filepath_or_buffer='test.csv', header=None, usecols=[1], names=['first_name'])
df

  first_name
0      Steve
1      Guido
2       John

edited Sep 7, 2015 at 18:20

answered Sep 7, 2015 at 16:56

Romain

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Shawn Mehan · Accepted Answer · 2017-05-24 20:35:51Z

4

import pandas as pd
data = pd.read_csv('file.csv', usecols=['column_name'])

Parameter of usecols contain list of column name(s). If want more than one columns,then separate them by comma i.e., ['column_name1, 'column_name2', 'column_name3']

edited May 24, 2017 at 20:35

Shawn Mehan

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answered May 24, 2017 at 20:10

Irfanullah

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