How do I iterate through nested lists of binary digits and append their decimal number to a list? ex: [[0,0,1,0,1],[1,0,0,0,1]]==[5, 17]

Question

binary_list = [['0', '0', '1', '0', '1'], ['1', '0', '1', '0', '1'], ['0', '0', '0', '0', '0'], ['0', '1', '0', '0', '1'], ['1', '1', '0', '0', '0'], ['0', '0', '1', '0', '1'], ['0', '0', '0', '1', '0'], ['0', '0', '1', '0', '0']]

cipher_value = []

cipher_num = 0

for list in binary_list:
        for num in range(len(list)):
         
            if num == 0 and list[num] == 1:
                cipher_num += 16
            elif num == 0 and list[num] == 0:
                continue
                
            if num == 1 and list[num] == 1:
                cipher_num += 8
            elif num == 1 and list[num] == 0:
                continue
                
            if num == 2 and list[num] == 1:
                cipher_num += 4
            elif num == 2 and list[num] == 0:
                continue
                
            if num == 3 and list[num] == 1:
                cipher_num += 2
            elif num == 3 and list[num] == 0:
                continue
            
            if num == 4 and list[num] == 1:
                cipher_num += 1
            elif num == 4 and list[num] == 0:
                continue
                
            cipher_value.append(cipher_num)
            cipher_num = 0
            break

Can you explain a bit more in detail what you are trying to do here ? — SARAN SURYA, Jan 11 '22 at 02:34
I have written a few different for loops but each one (including the one above) results in outputting cipher_value = [0,0,0,0,0,0,0,0] I don't understand why the cipher_num is not incrementally increasing when the requirements are met. I'm just learning so any and all help is appreciated!! — john sims, Jan 11 '22 at 02:34
Can you explain the question in a bit more detail ? The title alone doesn't help — SARAN SURYA, Jan 11 '22 at 02:35
While others are posting alternative solutions, note that in your original solution, `list[num] == 1` is comparing a string to an int, so it will always be false. You could change it to `list[num] == '1'`. — Dennis, Jan 11 '22 at 02:39
Yeah, the title only let me put so much lol So I am trying to iterate through each nested list in "binary_list" and append their representative value to the list "cipher_value" — john sims, Jan 11 '22 at 02:51
Wow! Thank you, Dennis! I feel like a total dingleberry! I need more coffee! — john sims, Jan 11 '22 at 02:53

j1-lee · Accepted Answer · 2022-01-11T02:51:59.047

2

You can use int(..., 2) to convert the binary representation (in string type) of a number into an integer. So, with help of join and list comprehension:

cipher_value = [int(''.join(sublist), 2) for sublist in binary_list]
print(cipher_value) # [5, 21, 0, 9, 24, 5, 2, 4]

edited Jan 11 '22 at 02:51

answered Jan 11 '22 at 02:37

j1-lee

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score 0 · Answer 2 · answered Jan 11 '22 at 02:36

For each element in the list, you can convert the binary representation to a decimal integer by using bit-shifting. This has the advantage of being able to work with a variable number of binary numbers, as well as variable-length binary numbers:

binary_list = [['0', '0', '1', '0', '1'], ['1', '0', '1', '0', '1'], ['0', '0', '0', '0', '0'], ['0', '1', '0', '0', '1'], ['1', '1', '0', '0', '0'], ['0', '0', '1', '0', '1'], ['0', '0', '0', '1', '0'], ['0', '0', '1', '0', '0']]

cipher_values = []
for binary_repr in binary_list:
    cipher_num = 0
    for bit in binary_repr:
        cipher_num <<= 1
        cipher_num += int(bit)
    cipher_values.append(cipher_num)
print(cipher_values)

How do I iterate through nested lists of binary digits and append their decimal number to a list? ex: [[0,0,1,0,1],[1,0,0,0,1]]==[5, 17]

2 Answers2