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

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

CodePudding user response：

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