CODEWITHSUNDEEP
pythonlistelementwise-operations
jchanger
jchanger

Reputation: 738

OR element wise operation over two binary lists

I have the following code of two binary lists and I want to obtain a resulting list in which the element i will be the OR operation applied to the i elements of the two lists:

from operator import ior  

l_0 = [01100]
l_1 = [11000]

print map(ior, l_0, l_1)

And I was expecting a result of [11100], but the result is:

[11000]

I have checked ior operator and the documentation says that it performs the operation:

a = ior(a, b) is equivalent to a |= b

So I tried the following to check as well:

print ior(0,0)
print ior(1,0)
print ior(0,1)
print ior(1,1)

Getting as results:

0
1
1
1

Which makes sense, but doesn't coincide with the result obtained in the 3rd position of the lists. I don't understand why the result of the map operation of above is not [11100]. I am missing something here and I hope that you can throw some light on it.

Upvotes: 0

Views: 796

Answers (2)

falsetru
falsetru

Reputation: 369364

01100 is octal representation (576 in decimal). 11000 is decimal representation. They are not binary representations.

To represent binary, prefix them with 0b:

[`01100`, `11000`]

And to get binary representation from the number use bin:

bin(num)

or

'{:b}'.format(num)

Upvotes: 0

paxdiablo
paxdiablo

Reputation: 882226

[11000] (for example) is not a list of five binary digits, it's a list of one decimal number, 11000.

Similarly, 01100 is a single octal number equal to 576 decimal, so:

11000d        = 0010101011111000b
01100o = 576d = 0000001001000000b
                -----------------
  perform or:   0010101011111000b = 11000d

That's why you're getting 11000 as the answer, exactly the same as if you'd done:

[l_0[i] | l_1[i] for i in range(len(l_0))]

If you want to process a list of five binary digits, that would be something like:

>>> l_0 = [0,1,1,0,0]
>>> l_1 = [1,1,0,0,0]
>>> [l_0[i] | l_1[i] for i in range(len(l_0))]
[1, 1, 1, 0, 0]

Upvotes: 3

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