Possible Duplicate:

How do I randomly select an item from a list using Python?

I have two arrays pool_list_X , pool_list_Y. Both have a numpy array as element in the list. So basically

```
pool_list_x[0] = [1 2 3 4] # a multidimensional numpy array.
```

and every element of pool_list_x has corresponding element in pool_list_y

```
which is to say, that pool_list_x[i] corresponds to pool_list_y[i]
```

Now. if I have to randomly select 10 elements from list_x (and hence the corresponding elements to list_y). how do i do this. I can think of a very naive way.. randomly generate numbers. and stuff.. but that is not very efficient.. what is the pythonic way to do this. Thanks

Not sure if I understand you one hundred percent, but I think using `zip`

and `random.sample`

might work:

```
import random
random.sample(zip(list_a,list_b), 10)
```

Some short explanations:

`zip`

will create a list of pairs, i.e. it ensures that you pick corresponding elements - if you pick one, you automatically get the other (`Zip([1,2,3],[4,5,6]) = [(1,4),(2,5),(3,6)]`

)`random.sample(l,n)`

randomly selects`n`

elements from a list`l`