Extract values from two columns of a dataframe and put it in a list

I have a dataframe as shown below:

df = 

 A  col_1   col_45   col_3
1.0   4.0    45.0    [1, 9]
2.0   4.0    NaN     [9, 10]
3.0   49.2   10.8    [1, 10]

The values in col_1 are of type float and the values in col_3 are in a list. For every row, I want to extract the values in col_1 and col_3 and put it together in a list.

I tried the following:

df[['col_1','col_3']].astype(float).values.tolist()

But it threw me a Value error: ValueError: setting an array element with a sequence..

I would like to have a list as follows:

[[4.0,1.0,9.0],
 [4.0,9.0,10.0],
 [49.2,1.0,10.0]]

Is there a way to do this?
Thanks.

>Solution :

Convert one element in col_1 to list then use merge two list like list_1 + list_2, You can use pandas.apply with axis=1 for iterate over each row:

>>> df.apply(lambda row: [row['col_1']] + row['col_3'], axis=1)
0      [4.0, 1, 9]
1     [4.0, 9, 10]
2    [49.2, 1, 10]
dtype: object

>>> df.apply(lambda row: [row['col_1']] + row['col_3'], axis=1).to_list()
[
    [4.0, 1, 9], 
    [4.0, 9, 10], 
    [49.2, 1, 10]
]