I want to make a func that return the amount of consecutive zero's.

print(consecutive_zeros("0100100001"))

should return 4

def consecutive_zeros(string):
    zeros = 0
    cache = 0
    for elem in range(len(string)):
        if string[elem] == "0":
            zeros  = 1
        elif string[elem] == "1":
            if zeros > cache:
                zeros = cache
                zeros = 0
        return cache

My func always returns 0 if i give it a string with numbers

for elem in range(len(string)):
    if string[elem] == "0":
        zeros  = 1

This should count every 0

elif string[elem] == "1":
        if zeros > cache:
            zeros = cache

This breaks the counter when 1 appearing and checks if the amount of the counted consecutive zeros is higher as the momentarily saved zeros

CodePudding user response：

I'm not really a Python guy, but I'd just use a regex here.

txt = "0100100001"

# Find all sub strings with 2 or more consecutive zeros
matches = re.findall("00 ", txt)

# Compute string lengths
lengths = map(lambda x: len(x), matches)

# Find Longest
max_zeros = max(lengths);

print(max_zeros)

CodePudding user response：

Here is a fix of your code:

def consecutive_zeros(string):
    zeros = 0
    cache = 0
    for elem in string:
        if elem == "0":
            zeros  = 1
            if zeros > cache:
                cache = zeros # this was inverted
        else:
                zeros = 0
    return cache # this was wrongly indented

consecutive_zeros("01001000010")

output: 4

I would personally use itertools.groupby and a comprehension:

from itertools import groupby 

s = '0100100001'

max(len(list(g)) for v,g in groupby(s) if v=='0')

output: 4

CodePudding user response：

You also need to check the current count after you finished the iteration, in case the max consecutive appearances is in the last sequence.

def consecutive_zeros(string):
    curr = 0
    max_consecutive_zeros = 0
    for ch in string:
        if ch == '0':
            curr  = 1
            continue
        else:
            if curr >= max_consecutive_zeros:
                max_consecutive_zeros = curr
            curr = 0
    if curr >= max_consecutive_zeros:
        max_consecutive_zeros = curr
    return maxmax_consecutive_zeros    
max_consecutive_zeros = consecutive_zeros("0100100001")

print(max_consecutive_zeros)
>> 4

CodePudding user response：

See @Nick B for a great (and fast!) answer.

But, if you want to use your solution;

1. Your function returns after the first loop - move your return such that it's aligned with your for loop

def consecutive_zeros(string):
    zeros = 0
    cache = 0
    for elem in range(len(string)):
        if string[elem] == "0":
            zeros  = 1
        elif string[elem] == "1":
            if zeros > cache:
                zeros = cache
                zeros = 0
    return cache #Aligned it such that data is returned at last

2. Your function returns cache which is never updated; you need to update that

def consecutive_zeros(string):
    zeros = 0
    cache = 0
    for elem in range(len(string)):
        if string[elem] == "0":
            zeros  = 1
        elif string[elem] == "1":
            if zeros > cache:
                cache = zeros #'zeros = cache' before
                zeros = 0
    return cache #Aligned it such that data is returned at last

3. Your code does not reset zeros - only when zeros>cache. Move zeros=0 outside the if zeros > cache but such that's still in the elif string[elem] == "1"

def consecutive_zeros(string):
    zeros = 0
    cache = 0
    for elem in range(len(string)):
        if string[elem] == "0":
            zeros  = 1
        elif string[elem] == "1":
            if zeros > cache:
                cache = zeros #'zeros = cache' before
            zeros = 0 #Move it such that it's updated whenever we reset our counter
    return cache #Aligned it such that data is returned at last

and then it works

4. Note, use for elem in string instead of for elem in range(len(string))

CodePudding user response：

In case your string just contains 0 and 1's, you could:

data = "0100100001"
print(max(len(x) for x in data.split('1')))

Print:

4