df.iloc[:, 0:4] code example

Example 1: iloc in dataframe

df=pd.read_csv('yourcsv.csv')
X=df.iloc[:,:-1].values
y=df.iloc[:,1].values

Example 2: iloc[:,0:-1]

>>> df.iloc[[0, 2], [1, 3]]
      b     d
0     2     4
2  2000  4000