I have a dataframe with column like this:

```
    column_1                    
0   0.25 / 0 / 0.25 / -0.25     
1   -0.25 / 0 /1                
2   0 / -0.5 / -0.25            
3   1/ 0.25 / -0.75             

```

each row is made of chain of consecutive numbers (separated by /)
I want to create 2 new column, and keep only the first element and the last element, like below example

```
    column_1                     new_column_1st_element   new_column_last_element
0   0.25 / 0 / 0.25 / -0.25      0.25                     -0.25
1   -0.25 / 0 /1                 -0.25                    1
2   0 / -0.5 / -0.25             0                        -0.25
3   1/ 0.25 / -0.75              1                        -0.75

```