CODEWITHSUNDEEP
pythonlist
Hamza
Hamza

Reputation: 560

How do I place the zeros at the top of list and 1's in the last?

I have written a code that takes place the zeros at the top of list and 1's at the end of it , but it increases the space and time complexity . How can I reduce the complexity of code.

Code:

array = [0, 1, 0, 1, 1, 0]
new_list = []
new_list1 = []
for i in array:
    if i == 0:
        new_list.append(i)
    else:
        new_list1.append(i)

print(new_list + new_list1)

Upvotes: 1

Views: 65

Answers (4)

cards
cards

Reputation: 4975

with sum (in case you are allowed to use sum, not clear from the question )

array = [0, 1, 0, 1, 1, 0]
n_ones = sum(array)
new_array = [0 for _ in range(len(array) - n_ones)] + [1 for _ in range(n_ones)]

Remark on booleans In python booleans are considered numeric types so you can do arithmetic as well. Working only with 0 and 1 as integers, so more structured data than boolean True and False, could give raise to performance "lack".

Notice also that python considers both boolean states as literals!

boolean approach

array = [0, 1, 0, 1, 1, 0]
n_ones = len([True for _ in array if bool(_)])
new_array = [0 for _ in range(len(array) - n_ones)] + [1 for _ in range(n_ones)]

Upvotes: -1

Metapod
Metapod

Reputation: 416

An other way without count and keeping the loops could be that:

array = [0, 1, 0, 1, 1, 0]
new_list = []

for val in array:
    if val == 1:
        new_list.append(1)
    else:
        new_list.insert(0, 0)

>> [0, 0, 0, 1, 1, 1]

Upvotes: 0

Andrej Kesely
Andrej Kesely

Reputation: 195428

Slightly modifying your code:

array = [0, 1, 0, 1, 1, 0]
new_list = []
for i in array:
    if i == 0:
        new_list.append(i)
new_list.extend(1 for _ in range(len(array) - len(new_list)))
print(new_list)

Prints:

[0, 0, 0, 1, 1, 1]

Upvotes: 0

phuycke
phuycke

Reputation: 331

If the output needs to be [0, 0, 0, 1, 1, 1]

you can do the following:

In [17]: 
array = [0, 1, 0, 1, 1, 0]
print([0] * array.count(0) + [1] * array.count(1))


Out[17]: [0, 0, 0, 1, 1, 1]

Upvotes: 2

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