X = dataset.iloc[: , 3: ].values code example

Example 1: what is .iloc[:, 1:2].values

>>> type(df.iloc[0])
<class 'pandas.core.series.Series'>
>>> df.iloc[0]
a    1
b    2
c    3
d    4
Name: 0, dtype: int64

Example 2: X = df.iloc[:, 1:]

X = df.iloc[:, 1:]