Selecting multiple dataframe columns by position in pandas [duplicate]

Question

I have a (large) dataframe. How can I select specific columns by position? e.g. columns 1..3, 5, 6

Rather than just drop column4, I am trying to do it in this way because there are a ton of rows in my dataset and I want to select by position:

 df=df[df.columns[0:2,4:5]]

but that gives IndexError: too many indices for array

DF input

 Col1     Col2     Col3       Col4        Col5       Col6
 1        apple    tomato     pear        banana     banana
 1        apple    grape      nan         banana     banana
 1        apple    nan        banana      banana     banana
 1        apple    tomato     banana      banana     banana
 1        apple    tomato     banana      banana     banana
 1        apple    tomato     banana      banana     banana
 1        avacado  tomato     banana      banana     banana
 1        toast    tomato     banana      banana     banana
 1        grape    tomato     egg         banana     banana

DF output - desired

 Col1     Col2     Col3       Col5       Col6
 1        apple    tomato     banana     banana
 1        apple    grape      banana     banana
 1        apple    nan        banana     banana
 1        apple    tomato     banana     banana
 1        apple    tomato     banana     banana
 1        apple    tomato     banana     banana     
 1        avacado  tomato     banana     banana     
 1        toast    tomato     banana     banana     
 1        grape    tomato     banana     banana

Answer 1

What you need is numpy np.r_

df.iloc[:,np.r_[0:2,4:5]]
Out[265]: 
   Col1     Col2    Col5
0     1    apple  banana
1     1    apple  banana
2     1    apple  banana
3     1    apple  banana
4     1    apple  banana
5     1    apple  banana
6     1  avacado  banana
7     1    toast  banana
8     1    grape  banana

Answer 2

You can select columns 0, 1, 4 in this way:

df.iloc[:, [0, 1, 4]]

You can read more about this in Indexing and Selecting Data.

• iloc is primarily integer position based (from 0 to length-1 of the axis), but may also be used with a boolean array. .iloc will raise IndexError if a requested indexer is out-of-bounds, except slice indexers which allow out-of-bounds indexing. (this conforms with python/numpy slice semantics). Allowed inputs are:

◦ An integer e.g. 5

◦ A list or array of integers [4, 3, 0]

◦ A slice object with ints 1:7

◦ A boolean array

◦ A callable function with one argument (the calling Series, DataFrame or Panel) and that returns valid output for indexing (one of the above)