Find repetitive number patterns-CodePudding

I'm trying to find repetitive pattern of number inside array.

For ex: if i have Array ( [0] => 0 [1] => . [2] => 1 [3] => 4 [4] => 2 [5] => 8 [6] => 5 [7] => 7 [8] => 1 [9] => 4 [10] => 2 [11] => 8 [12] => 5 [13] => 7 [14] => 1 [15] => 4 )

i want to know that from [2] to [7] & [8] to [13] i have the same pattern of 142857.

whatever language suits you best , just trying to figure out how to attack this problem.

Thank you.

CodePudding user response：

I have broke the loop if atleast one repetitive pattern is found, you can continue looking for patterns if you want,

Also used pattern_length = 6 because there will be lot of repetitions for pattern_length = 1.

arr = [0,'.',1,4,2,8,5,7,1,4,2,8,5,7,1,4]

pattern_length = 6;

arr2 = [];

arr3 = [];

repetitive_string = '';

for(i=0;i<arr.length;i  ){
   str = '';
    for(j=i;j<i pattern_length;j  ){
       if(arr[j] || arr[j]===0)
        str =arr[j];
       else
        break;
    }
    if(arr2.includes(str)){
      repetitive_string = str;
      arr3.push(arr2.indexOf(str));
      arr3.push(i);
      break;
    }
    arr2.push(str);
  }

if(repetitive_string){
  console.log('Repetitive string found - ' repetitive_string ' at ' arr3[0] '-' (arr3[0] (pattern_length-1)) ' and ' arr3[1] '-' (arr3[1] (pattern_length-1)))
}else{
  console.log('No repetitive string for the mentioned pattern length')
}

CodePudding user response：

With python.

Using slices of string

group = '142857'

arr = [0,1,4,2,8,5,7,1,4, 2, 3, 1]

arr_as_str = ''.join(map(str, arr))
n_grp, n_arr = len(group),  len(arr_as_str)

match_positions = []
for i in range(n_grp):
    for j in range((n_arr-i)//n_grp):
        arr_group = arr_as_str[i j*n_grp: i (j 1)*n_grp]
        if arr_group == group:
            match_positions  = [(i j*n_grp, i (j 1)*n_grp)]

print(f'The pattern "{group}" occours in "{arr_as_str}"" at the following positions:')
print(match_positions)

And using a regular expression:

import re
arr = [0,'.',1,4,2,8,5,7,1,4,2,8,5,7,1,4]
arr_as_str = ''.join(map(str, arr))
group = '142857'

regex = r'(?P<g>{})'.format(group)
print([match.span() for match in re.finditer(regex, arr_as_str)])

Remark: is nonsense the output that you asked: "i want to know that from [2] to [7] & [8] to [13] i have the same pattern of 142857." because the pattern consist of 6 characters but the length of the given intervals are 5. So, the results in both implementations will be [(2, 8), (8, 14)]