I'm trying to write a function that will take a list of 1's and 0's an as argument, and will return the number of consecutive 1's in the list. E.g. a list [1, 1, 1, 1] should return 4, and a list [1,0,1,1] should return 2.

I've written the following function:

Note: the argument "result" is a list of 1's and 0's.

def count_consecutive_ones(result):
  
    for i in range (0, len(result)):
        num_ones = int(0)
        print(str(num_ones)   "is the num of ones")
        if create_binary(i) == 1.0:
            num_ones  = num_ones
            print(num_ones)
    return(num_ones)

new_result = count_consecutive_ones(result)
print(new_result)

When I input [1.0, 1.0, 1.0, 1] as the result list, I receive:

0is the num of ones
0is the num of ones
[1]
0is the num of ones
[0]
[1.0, 0]
0is the num of ones
[1]
[1.0, 1]
0

In other words, it looks like num_ones does not increase as the for loop iterates.

Why not?

I'm new to Python / programming so thank you for your patience!

I've tried changing the inputs of "result", but this hasn't gotten me very far. I'd appreciate any advice!

CodePudding user response：

This is because at the top of the for loop, I believe you are resetting the value of num_ones to 0. Therefore, every time, you are receiving a value of 0 which is being printed out. Consider moving this assignment upward so it is not continually reassigned back to 0 at each iteration of the for loop. Or, create another variable as well.

CodePudding user response：

I created this sample hope it helps:

binaries = [1, 1, 0, 1]

def count_consecutive_ones(binaries):
    current_consecutive_ones = 0
    max_consecutive_ones = 0
    for i in range(len(binaries)):
        if binaries[i] == 1:
            current_consecutive_ones  = 1
        else:
            current_consecutive_ones = 0
        if current_consecutive_ones > max_consecutive_ones:
            max_consecutive_ones = current_consecutive_ones

    return (max_consecutive_ones)

result = count_consecutive_ones(binaries)
print(f"the longest series of consecutive ones was {result}") 

CodePudding user response：

So you actually need additional variables to solve this problem...

1. variable to hold consecutive 1s
2. variable to hold maximun onsecutive 1s

def count_consecutive_ones(result):

max_consecutive_ones = 0
consecutive_ones = 0

for i in range(0, len(result)):
    num_ones = int(result[i])
    if num_ones == 0:
        consecutive_ones = 0
    else:
        consecutive_ones  = 1
        max_consecutive_ones = max(max_consecutive_ones, consecutive_ones)

    print(str(consecutive_ones)   "is the num of ones")

return(max_consecutive_ones)

CodePudding user response：

The other answer has explained what you did wrong, here are some solutions to the problem:

First here is my way of doing it:

result = [1, 1, 1, 0, 1, 1, 1, 1, 1]
def count_consecutive_ones(result):
  result = [int(i) for i in result]
  consecutives = []
  consecutive = 0
  prev = 0
  for i in result:
    if i == 1 and prev == 1:
      consecutive  = 1
    elif i == 1:
      prev = 1
      consecutive  = 1
    else:
      consecutives.append(consecutive)
      consecutive = 0
      prev = 0
  consecutives.append(consecutive)
  return max(consecutives)
    

new_result = count_consecutive_ones(result)
print(new_result)

Output:

5

All this does is loop through result and every time there is a 1 add 1 to the consecutive count. When a 0 comes up the count is reset and added to a list of counts. The function returns the max of this list.

You could also use .split:

result = [1, 1, 1, 0, 1, 1, 1, 1, 1]
def count_consecutive_ones(result):
  result = [int(i) for i in result]
  result_str = ''.join([str(i) for i in result])
  result_str_split = result_str.split('0')
  return len(max(result_str_split))
new_result = count_consecutive_ones(result)
print(new_result)

Output:

5

This just uses the python str method .split() which returns a list object where each item is the characters that occur between each character that the str is split by.

Thus '11101'.split(str(0)) returns ['111', '1']