How to detect lowercase letters in Python 3.2?

Question

Okay, I'm not really getting the answers I was looking for so I'll try rewording this. I need to know if there is a function that detects the lowercase letters in a string. Say I started writing this program:

s = input('Type a word')

Would there be a function that lets me detect a lowercase letter within the string s? Possibly ending up with assigning those letters to a different variable, or just printing the lowercase letters or number of lowercase letters.

While those would be what I would like to do with it I'm most interested in how to detect the presence of lowercase letters. The simplest methods would be welcome, I am only in an introductory python course so my teacher wouldn't want to see complex solutions when I take my midterm. Thanks for the help!

Have you had a chance to go over the `str` documentation yet? — Ignacio Vazquez-Abrams, Oct 17 '12 at 02:24
Do you need to support non-ascii letters? Do you care if solution treats Unicode codepoints and user-percieved characters the same e.g., if it looses diacritics for some letters? — jfs, Oct 17 '12 at 03:20
@Blender: try `'u\u0308ü'`. Also `filter()` doesn't return a string for a string input in Python 3. — jfs, Oct 17 '12 at 03:36

cdarke · Answer 1 · 2012-10-17T03:07:48.527

Using a regular expression is probably the simplest way:

# Python 3 version

import re

txt = 'MarMaLadE'

# Replace uppercase with "" - an empty string
ltxt,n = re.subn(r'[A-Z]', "", txt) 

print("lower case letters:"," ".join(set(ltxt)))
print("number of lc letters:", n)

The use of set removes duplicate lowercase letters, you might not want that. You might also want to consider which characters are uppercase, is A-Z sufficient? See also the re.LOCALE flag.

score 0 · Answer 2 · answered Oct 17 '12 at 02:49

Hope this helps, keep in mind that python is wary of indentation. This is not a very good solution but it works.

def doWhatYouWantToDo(input):
 newString = ""
 alphabet = "abcdefghijklmnopqrstuvwxyz"
 for letter in input:
  if letter in alphabet:
   newString += letter
 return newString

yourString = 'MarMaLadE'
print doWhatYouWantToDo(yourString)
print len(doWhatYouWantToDo(yourString)

How to detect lowercase letters in Python 3.2?

2 Answers2