iloc[:, 3:] means in dataframe 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: return df.iloc[1:]

>>> df.iloc[1:3, 0:3]
      a     b     c
1   100   200   300
2  1000  2000  3000