# Split a list with a adjustable ratio

## Question:

so i am trying to create a function that split a list with values with an adjustable ratio.

To just split the list in half i have this function:

``````def list_splitter(list_to_split):

half = len(list_to_split) // 2
return list_to_split[:half], list_to_split[half:]
``````

Where list_to_split has 1000 objects. But i want to do something like this:

``````def list_splitter(list_to_split, ratio):

part1 = len(list_to_split) * ratio
part2 = 1 - ratio
return list_to_split[:part1], list_to_split[part2:]
``````

So for example i want to be able to set ratio = 0.75, so that 0.75% (750 objects) is added in the first part, and 250 in the other part.

Well, something like this should do it:

``````def list_splitter(list_to_split, ratio):
elements = len(list_to_split)
middle = int(elements * ratio)
return [list_to_split[:middle], list_to_split[middle:]]
``````

You can do like this:
If your ratio will change every time, then:

``````def list_splitter(list_to_split, ratio):
first_half = int(len(list_to_split) * ratio)
return list_to_split[:first_half], list_to_split[first_half:]
``````

A one-liner using numpy

``````import numpy as np

l = np.random.rand(1000)
ratio = 0.75

y = np.split(l, [round(len(l) * ratio), len(l)])

print(len(y[0]), len(y[1]))
``````
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