List of entries in header in text file using python

Question

I have a .txt file where I have text headers and numerical data. I am working with python 2.7, and am using pandas and numpy in my work. The structure of the file is like the picture shown below:

The data for this file can be gotten from here. In this file, I want to get a list of all tags. For example, in the picture shown above, I want the list to look like the following:

[Tag1, Tag1, Tag1, Tag5, Tag5, Tag6, Tag6]

At present, I am reading the file using:

df = pd.read_csv('dum.txt',sep='\t', header=[0,1], index_col=0)

When I try lst = df.columns.levels[1], I get Index([u'Tag1', u'Tag5', u'Tag6'], dtype='object', name=u'Tag') as my output instead of the list that I desire.

How can I get a list of tags in my problem, i.e. [Tag1, Tag1, Tag1, Tag5, Tag5, Tag6, Tag6] ? Thanks in advance.

sacuL · Accepted Answer · 2018-10-25 16:04:41Z

2

You can use get_level_values(1) instead of levels[1], then convert to list using tolist():

>>> df.columns.get_level_values(1).tolist()
['Tag1', 'Tag1', 'Tag1', 'Tag5', 'Tag5', 'Tag6', 'Tag6']

The reason is that levels[1] will give you, as you saw, a list of all unique levels, whereas get_level_values will actually return:

Return vector of label values for requested level, equal to the length of the index

answered Oct 25, 2018 at 16:04

sacuL

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2 Comments

Scott Boston Over a year ago

Nice answer! :) I deleted. +1

Ling Guo Over a year ago

Thanks sacul! Your answer was very helpful. :)

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