The values of my 1st column are going into the index but the column name is the 1st column outside the index

Question

The values of my first column are going into the index but the column name is the first column outside the index, so I cannot use df.reset_index. For instance, my dataframe looks like this:

	CHA_NUMB	CHA_NAME	UN_CHA_ID
1	m_3_1	12345	lcha
2	t_1_2	12456	lcha
3	blah	90244	lcha
4	blah	23435	lcha

When it should look like this:

	CHA_NUMB	CHA_NAME	UN_CHA_ID
0	1	m_3_1	12345
1	2	t_1_2	12456
2	3	blah	90244
3	4	blah	23435

I tried resetting the index but it didn’t work. Resetting the index makes the dataframe look like this:

	index	CHA_NUMB	CHA_NAME	UN_CHA_ID
0	0	m_3_1	12345	lcha
1	1	t_1_2	12456	lcha
2	2	blah	90244	lcha
3	3	blah	23435	lcha

Asked By: Muhammad Raffae

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Source

Answer 1

First use DataFrame.reset_index, then remove last column by indexing in DataFrame.iloc and last set columns names by original DataFrame by DataFrame.set_axis:

df = df.reset_index().iloc[:, :-1].set_axis(df.columns, axis=1)
print (df)
   CHA_NUMB CHA_NAME  UN_CHA_ID
0         1    m_3_1      12345
1         2    t_1_2      12456
2         3     blah      90244
3         4     blah      23435

Alternative:

cols = df.columns
df = df.reset_index().iloc[:, :-1]
df.columns = cols

EDIT: If first row of columns names not matched data you can omit columns names by header=None and skiprows=1, get columns names like RangeIndex, then use usecols for select first and third column and last set columns names by names parameter:

df = pd.read_csv(file, 
                 header=None, 
                 skiprows=1, 
                 usecols=[0,2], 
                 names=['CHA_NUMB','UN_CHA_ID'])
    
print (df)
   CHA_NUMB  UN_CHA_ID
0         1      12345
1         2      12456
2         3      90244
3         4      23435

Answered By: jezrael

The values of my 1st column are going into the index but the column name is the 1st column outside the index

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