# How to generate all subarray or list in the given list or array using python

## A different form of this Problem Statement

• print all sublists in list
• print all subarray in array using python
• find all subarrays of an array

User: Oh wait but what does subarray really mean, Can you please elaborate it using some example?

Okay, So let start explanation using some example.

```Input : List = [1, 2, 3]
Output : [[], [1], [2], [3], [1, 2], [2, 3], [1,2,3]]

Input : List = [1, 2, 3, 4]
Output : [[], [1], [2], [3], [4], [1, 2], [2, 3], [3, 4], [1, 2, 3], [2, 3, 4], [1, 2, 3, 4]]```

User: Wait, Sorry to say, but you have forgotten to mention [1, 3] in the first example.

Thanks to mention this, But it is not wrong example, [1, 3] will definetly get a place, when we are finding out the permutation and combination of list to generate a pair. But Here we are generating just sublist of list. Both case are different.

User: Okay,Now I have better understanding. So Now what will be the approach to solve this condition.

Okay, Let’s move on the approach of this statement.

Approach will be that we are going to run two nested loop till the length of the given list. The outer loop will pick up starting element and inner loop will considers all elements on right of the picked elements as ending element of subarray. To do this thing, slicing would be better to get subarray.

To make it more simple, Here is the Five step process to approach this statement.

User : It looks cool can you please provide me code for this approach.

Why not, Let write code for this approach using python.

```"""
function to generate all the sub lists
"""
def generate_sub_lists(arr):

# store all the sublists
sub_list = [[]]

# first loop
for i in range(len(arr) + 1):

# second loop
for j in range(i + 1, len(arr) + 1):

# slice the sublist
sub = arr[i:j]
sub_list.append(sub)

return sub_list

arr = [1, 2, 3]
print(generate_sub_lists(arr))

# Code published on Freshlybuilt.com```

## Output

`[[], [1], [1, 2], [1, 2, 3], [2], [2, 3], [3]]`

This is the output of the program, that is generated using the above code.

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