如何在 python 中对字符串进行切片？

Question

I am trying to do slicing in string "abcdeeefghij" , here I want the slicing in such a way that whatever input I use, i divide the output in the format of a list (such that in one list element no alphabets repeat).

In this case [abcde,e,efghij] .

Another example is if input is "aaabcdefghiii" . Here the expected output is [a,a,acbdefghi,i,i] .

Also amongst the list if I want to find the highest len character i tried the below logic: max_str = max(len(sub_strings[0]),len(sub_strings[1]),len(sub_strings[2])) print(max_str) #output - 6

which will yield 6 as the output, but i presume this logic is not a generic one: Can someone suggest a generic logic to print the length of the maximum string.

Answer 1

Here is how:

s = "abcdeeefghij"

l = ['']

for c in s: # For character in s
    if c in l[-1]: # If the character is already in the last string in l
        l.append('') # Add a new string to l
    l[-1] += c # Add the character to either the last string, either new, or old

print(l)

Output:

['abcde', 'e', 'efghij']

Answer 2

Use a regular expression:

import re
rx = re.compile(r'(\w)\1+')

strings = ['abcdeeefghij', 'aaabcdefghiii']

lst = [[part for part in rx.split(item) if part] for item in strings]
print(lst)

Which yields

[['abcd', 'e', 'fghij'], ['a', 'bcdefgh', 'i']]

Answer 3

You would loop over the characters in the input and start a new string if there is an existing match, otherwise join them onto the last string in the output list.

input_ = "aaabcdefghiii"

output = []

for char in input_:
    if not output or char in output[-1]:
        output.append("")
    output[-1] += char

print(output)

Answer 4

To avoid repetition of alphabet within a list element repeat, you can greedily track what are the words that are already in the current list. Append the word to your answer once you detected a repeating alphabet.

from collections import defaultdict

s = input()
ans = []
d = defaultdict(int)
cur = ""
for i in s:
    if d[i]:
        ans.append(cur)
        cur = i # start again since there is repeatition
        d = defaultdict(int)
        d[i] = 1
    else:
        cur += i #append to cur since no repetition yet
        d[i] = 1
if cur: # handlign the last part
    ans.append(cur)
print(ans)

An input of aaabcdefghiii produces ['a', 'a', 'abcdefghi', 'i', 'i'] as expected.