Longest consecutive substring of certain character type in python

问题

Is there a pythonic way to find the length of the longest consecutive substring of a certain character type, for instance the length of the longest consecutive substrings of digits/letters/printable characters?

For example in

s = "43gfd**54452**jhg4**fddsgf**"

The longest digit substring is of length 5, and the longest letter substring is of length 6.

回答1:

Regex and max with length as the key:

In [12]: s = "43gfd54452jhg4fddsgf"

In [13]: max(re.findall(r'\d+', s), key=len)  # digits
Out[13]: '54452'

In [14]: max(re.findall(r'\D+', s), key=len)  # non-digits
Out[14]: 'fddsgf'

Similarly, you can change the Regex pattern to get your desired substring type.

回答2:

If there are always "**" between each substring. All you have to do is iterate over the different elements, keeping in a variable the longest substring you have found so far.

longest_letter = 0
longest_digit = 0
for el in s.split("**"):
    if(el.isalpha()):
        len_letter = len(el)
        if(len_letter > longest_letter):
            longest_letter = len_letter
    if(el.isdigit()):
        len_digit = len(el)
        if(len_digit > longest_digit):
            longest_digit = len_digit
print (longest_letter)
print (longest_digit)

来源：https://stackoverflow.com/questions/54517998/longest-consecutive-substring-of-certain-character-type-in-python