Need help converting a list to a string

Question

The function here just generates a random list of 0s and 1s. It's for later use in a game. So I need to take the list generated by binary_gen and convert it to a string. I've tried using .join but I just get an error message back. Is there any way for me to convert the output from binary_gen to a string? Or is there another way I can generate a random sequence of 0s and 1s?

import random

def random_binary():
    min_length = 4
    max_length = 8
    binary_gen = [random.randrange(0,2,1) for _ in range \
    (random.randint(min_length,max_length))]
    print (binary_gen)

random_binary()

Update:

import random

def random_binary():
    min_length = 4
    max_length = 8
    binary_gen = [random.randrange(0,2,1) for _ in range \
    (random.randint(min_length,max_length))]
    binary_string = "".join(binary_gen)
    print (binary_string)

random_binary()

And I get: TypeError: sequence item 0: expected str instance, int found

Answer 1

To generate a random string sequence of zeroes and ones of random length from 4 to 8:

>>> from random import randint
>>> ''.join(str(randint(0, 1)) for i in range(randint(4, 8)))
'0010111'

Or, more directly:

>>> from random import choice, randint
>>> ''.join(choice('01') for i in range(randint(4, 8)))
'101101'

Counting

To count the number of 1 s in a string of zeroes and ones:

>>> s = '0011100'
>>> len(s.replace('0', ''))
3

Or:

>>> sum(c=='1' for c in s)
3

Answer 2

import random

def random_binary(min_length=4, max_length=8):
    size = random.randint(min_length, max_length)
    return ''.join(str(random.randint(0, 1)) for _ in range(size))    

print(random_binary())

My guess is that the error you got was something like TypeError: sequence item 0: expected str instance, int found , because you were trying to join numbers instead of strings. The str(...) above is what makes this code work.

Answer 3

Please try following:

import random

def random_binary():
    min_length = 4
    max_length = 8
    binary_gen = [random.randrange(0,2,1) for _ in range \
    (random.randint(min_length,max_length))]
    _str = ''
    for i in binary_gen:
        _str += str(i)
    return _str



def count_zeros(s):
    count = 0
    for i in s:
        if i == '0':
            count += 1
    return count

It generates '111010' string. count_zeros(s) will return number of zeros in input string