How to count the frequency of characters in a string in a row?

Question

input = 'XXYXYYYXYXXYYY'

output = [2,1,1,3,1,1,2,3]

How would count the number of X's and Y's in a string in the order that they are inputted and then put those values in a list?

Answer 1

import itertools
numbers = []
input = 'XXYXYYYXYXXYYY'
split_string = [''.join(g) for k, g in itertools.groupby(input)]

for i in split_string:
    numbers.append(len(i))
print(numbers)

Output:

[2, 1, 1, 3, 1, 1, 2, 3]

Answer 2

You could do this using a while loop by iterating the whole list.

str = 'XXYXYYYXYXXYYY';
i = 0
output = []
k = 1
while i < len(str) - 1:
   if str[i] == str[i+1]:
      k = k + 1
   else:
      output.append(k)
      k = 1
   i = i + 1
output.append(k)
print(output)

Output

[2, 1, 1, 3, 1, 1, 2, 3]

Answer 3

Try using itertools.groupby:

from itertools import groupby
s = 'XXYXYYYXYXXYYY'
print([len(list(i)) for _, i in groupby(s)])

Answer 4

Short solution using regex

import re
s = 'XXYXYYYXYXXYYY'
l = [len(m.group()) for m in re.finditer(r'(.)\1*', s)]

Based on this answer

Answer 5

Here's what you can try

test = 'XXYXYYYXYXXYYY'
count = 1
result_list = list()
prev_char = test[0]
for char in test[1:]:
    if char == prev_char:
        count+=1
        prev_char = char
    else:
        result_list.append(count)
        count=1
        prev_char = char
result_list.append(count)
print(result_list)

Output

[2, 1, 1, 3, 1, 1, 2, 3]

Answer 6

Without any libs it will be like this:

string = 'XXYXYYYXYXXYYY'

res = []
current = ''
for char in string:
    if current == char:
        res[-1] += 1
    else:
        res.append(1)
    current = char

print('res', res) # [2,1,1,3,1,1,2,3]

Answer 7

Try This.

input1 = 'XXYXYYYXYXXYYY'
output_list = []

count = 1

for index in range(len(input1)-1):
    if input1[index] == input1[index+1]:
        count += 1
    else:
        output_list.append(count)
        count = 1

if input1[-1] == input1[-2]:
    output_list[-1] += 1
else:
    output_list.append(1)
print(output_list)

Answer 8

The basic approach is to occurrences and stop if new char come. Code is below.

list_of_consec = []
def consec_occur(strr):
    i = 0
    cc = []
    while ( i < len(strr) -1 ):
        count =1
        while strr[i] == strr[i+1]:
            i += 1
            count += 1
            if i + 1 == len(strr):
                break
        cc.append(count)
        i += 1
    return (cc)
if __name__ == "__main__":
    print(consec_occur('XXYXYYYXYXXYYY'))

You can change the code according to your need. If you want list then make cc global and remove return statement and in print statement use cc.