I am trying to iterate through a string and mark () around the longest repeated adjacent values. Example:
"344556(7777)5412"
max_run = "0"
J = "34455677775412"
for x in range(len(J)-1):
if J[x] == J[x+1]
if J[x:x+2] > max_run:
print( "(", end = "")
max_run = J[x:x+2]
print( ")", end = "")
The method groupby from package itertools of the standard library sequentially group terms, then take the maximum.
import itertools as it
ref_string = "34455677775412"
max_squence = ''.join(max(list(j) for _, j in it.groupby(ref_string)))
print(ref_string.replace(max_squence, f'({max_squence})'))
Love itertools, but as there is already a (nice) solution withgroupby, here is one with a classical loop:
J = "34455677775412"
run = []
prev = None
for pos, char in enumerate(J):
if char == prev:
run[-1][0] += 1
else:
run.append([1, pos])
prev = char
print(run)
a,b = max(run, key=lambda x: x[0])
J[:b]+'('+J[b:b+a]+')'+J[b+a:]
output: '344556(7777)5412'
In case you can't use any standard library methods like groupby, here's a plain python implementation that does the same thing:
i = 0
max_start, max_end = 0, 0
J = "34455677775412"
# find the longest repeating sequence
while i < len(J):
j = i
while j < len(J) and J[j] == J[i]:
j += 1
max_start, max_end = max([(max_start, max_end), (i, j)], key=lambda e: e[1] - e[0])
i = j
print(max_start, max_end, J[max_start:max_end])
J = J[:max_start] + "(" + J[max_start:max_end] + ")" + J[max_end:] # insert the parentheses
print(J)
You could also use Python regex library re to achieve a similar solution to @cards's one
import re
J = "34455677775412"
pattern = r'(.)\1+'
longest_sequence = max([match.group() for match in re.finditer(pattern, J)])
print(J.replace(longest_sequence, f'({longest_sequence})'))
