How to move a boolean value from one array to another in python

Question

I am recently solving a coding problem. It ask me to move all 0s in one array to the end of the array. Like [0, 1, 1, 0, 0, 1]->[1, 1, 1, 0, 0, 0].

The reality is there could be any type of data in the original array, for example, [0, "A", 1 , None, False, True, 0, 0, 20, 1, 0.0]

what I am doing is looping the array, compare if it is 0, if it is, put it into another array. If it is not, increase the counter, at the end put the same amount of 0s as the counter. However, it treats the Boolean Value False as 0, so I can't do this, I am just curious if there is a way that can separate False from 0, and put into another array as False in Python. Thanks.

Is this an assignment where it's asking for algorithm design or can you just use sorted in rev order? — syntaxError
– syntaxError, Commented Jul 2, 2017 at 14:51
False is implemented as 0 but has an other type. So, check value and type! — Klaus D.
– Klaus D., Commented Jul 2, 2017 at 14:55
@cᴏʟᴅsᴘᴇᴇᴅ That's because isinstance() check for supertypes as well. Use type(False) == int instead. — Klaus D.
– Klaus D., Commented Jul 2, 2017 at 15:02
@KlausD. I concur, what I meant to say was that simply checking type isn't enough... — cs95
– cs95, Commented Jul 2, 2017 at 15:03

syntaxError · Accepted Answer · 2017-07-02 14:54:04Z

1

Use the test in your algorithm, to check if the value is the integer 0 and not the bool.

test = lambda x: True if x is 0 else False

list_ = [0, "A", 1 , None, False, True, 0, 0, 20, 1, 0.0]

print(sorted(list_, key=test)) #['A', 1, None, False, True, 20, 1, 0.0, 0, 0, 0]

answered Jul 2, 2017 at 14:54

syntaxError

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3 Comments

LVmiao Over a year ago

In the problem, 0.0 is treat as 0, if it is detected, it will be put to the end of the array with a 0, not 0.0.

syntaxError Over a year ago

0.0 is 0 >>>False

LVmiao Over a year ago

I tried your way, 0.0 is put back as 0.0, in the problem if a 0.0 need to be 0 and put back. For example, [1, 0, 0, 2, 0.0, 1] should be [1,2,1,0,0,0]

idjaw · Accepted Answer · 2017-07-02 14:52:36Z

0

You can make use of is which does an identity comparison. Observe the following example:

>>> n = 0
>>> n is 0
True
>>> n is False
False
>>> False is n
False

answered Jul 2, 2017 at 14:52

idjaw

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Comments

Victor Andres Aguirre Fernande · Accepted Answer · 2020-10-16 05:42:58Z

0

I run into some issues with 0.0 so, i made some changes

array = [0, "A", 1 , None, False, True, 0, 0, 20, 1, 0.0]
filt = lambda x: True if x==0 and type(x) is not bool else False
print(sorted(array,key=filt))

The x==0 will allow you to filter the float, and type(x) in not bool will help you with the boolean False

answered Oct 16, 2020 at 5:42

Victor Andres Aguirre Fernande

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