How to detect lowercase letters in Python

Question

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

User · Answer

If you don t want to use the libraries and want simple answer then the code is given below     def swap alpha test string         new string            for i in test string            if i upper   in test string                new string    i lower              elif i lower                    new string    i upper              else                return  invalid          return new string   user string   input  enter the string    updated   swap alpha user string  print updated

User · Answer

There are 2 different ways you can look for lowercase characters    Use str islower   to find lowercase characters  Combined with a list comprehension  you can gather all lowercase letters   lowercase    c for c in s if c islower     You could use a regular expression   import re  lc   re compile   a-z     lowercase   lc findall s     The first method returns a list of individual characters  the second returns a list of character groups    gt  gt  gt  import re  gt  gt  gt  lc   re compile   a-z      gt  gt  gt  lc findall  AbcDeif     bc    eif

User · Answer

import re s   raw input  Type a word     slower    join re findall r  a-z   s   supper    join re findall r  A-Z   s   print slower  supper   Prints   Type a word  A Title of a Book itleofaook ATB   Or you can use a list comprehension   generator expression   slower    join c for c in s if c islower    supper    join c for c in s if c isupper    print slower  supper   Prints   Type a word  A Title of a Book itleofaook ATB

User · Answer

To check if a character is lower case  use the islower method of str  This simple imperative program prints all the lowercase letters in your string   for c in s      if c islower             print c   Note that in Python 3 you should use print c  instead of print c        Possibly ending up with assigning those letters to a different variable    To do this I would suggest using a list comprehension  though you may not have covered this yet in your course    gt  gt  gt  s    abCd   gt  gt  gt  lowercase letters    c for c in s if c islower     gt  gt  gt  print lowercase letters   a    b    d     Or to get a string you can use    join with a generator    gt  gt  gt  lowercase letters      join c for c in s if c islower     gt  gt  gt  print lowercase letters  abd

User · Answer

There are many methods to this  here are some of them    Using the predefined str method islower      gt  gt  gt  c    a   gt  gt  gt  c islower   True  Using the ord   function to check whether the ASCII code of the letter is in the range of the ASCII codes of the lowercase characters    gt  gt  gt  c    a   gt  gt  gt  ord c  in range 97  123  True  Checking if the letter is equal to it s lowercase form    gt  gt  gt  c    a   gt  gt  gt  c lower      c True  Checking if the letter is in the list ascii lowercase of the string module    gt  gt  gt  from string import ascii lowercase  gt  gt  gt  c    a   gt  gt  gt  c in ascii lowercase True    But that may not be all  you can find your own ways if you don t like these ones  D   Finally  let s start detecting   d   str input  enter a string       lowers    c for c in d if c islower       here i used islower   because it s the shortest and most-reliable   one  being a predefined function   using this list comprehension   is  probably  the most efficient way of doing this

User · Answer

You should use raw input to take a string input  then use islower method of str object      s   raw input  Type a word   l      for c in s strip        if c islower            print c         l append c  print  Total number of lowercase letters   d   len l    1    Just do -    dir s    and you will find islower and other attributes of str

[python] How to detect lowercase letters in Python?

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