CODEWITHSUNDEEP
pythonregexcharacteralphabetical
user2104778
user2104778

Reputation: 1040

Python regex find all single alphabetical characters

I want to find all indexes for each occurrence of single alphabetical characters in a string. I don't want to catch single char html codes.

Here is my code:

import re
s = "fish oil B stack peanut c <b>"
words = re.finditer('\S+', s)
has_alpha = re.compile(??????).search
for word in words:
    if has_alpha(word.group()):
        print (word.start())

Desired output:

9
24

Upvotes: 2

Views: 4961

Answers (3)

Loamhoof
Loamhoof

Reputation: 8293

In the most general case I'd say:

re.compile(r'(?i)(?<![a-z])[a-z](?![a-z])').search

Using lookarounds to say "a letter not preceded by another letter nor followed by another letter".

Upvotes: 1

Inbar Rose
Inbar Rose

Reputation: 43457

Using your format (as you wanted) but adding only a simple check.

import re
s = "fish oil B stack peanut c <b>"
words = re.finditer('\S+', s)
has_alpha = re.compile(r'[a-zA-Z]').search
for word in words:
    if len(word.group()) == 1 and has_alpha(word.group()):
        print (word.start())
>>> 
9
24

Upvotes: 2

RichieHindle
RichieHindle

Reputation: 281515

This does it:

r'(?i)\b[a-z]\b'

Breaking it down:

  • Case insensitive match
  • A word boundary
  • A letter
  • A word boundary

Your code can be simplified to this:

for match in re.finditer(r'(?i)\b[a-z]\b', s):
   print match.start()

Upvotes: 6

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