CODEWITHSUNDEEP
pythonpython-3.x
Bob
Bob

Reputation: 761

How to determine if character is uppercase, lowercase, digit, or non-alphanumeric without string methods

I'm trying to write a program that determines if a character is uppercase, lowercase, digit, or non-alphanumeric without string methods like isupper, islower, isdigit. The program is that everything I enter, it's telling me that its a lower case letter. Can someone help me out? 

character = input("Enter a character: ")

lowerLetters = "abcdefghijklmnopqrstuvwxyz"
upperLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
digits = "0123456789"
lowerCount = 0
upperCount = 0
digitCount = 0
nonAlphaCount = 0

for ch in character:
    for ch in lowerLetters:
        lowerCount += 1
    for ch in upperLetters:
        upperCount += 1
    for ch in digits:
        digitCount += 1
    else:
        nonAlphaCount += 1

if lowerCount > 0:
    print(character, "is a lower case letter.")
elif upperCount > 0:
    print(character, "is an upper case letter.")
elif digitCount > 0:
    print(character, "is a digit.")
elif nonAlphaCount > 0:
    print(character, "is a non-alphanumeric character.")

Upvotes: 3

Views: 13705

Answers (3)

Kasravnd
Kasravnd

Reputation: 107287

The problem is with following part of your code :

for ch in character:
    for ch in lowerLetters:
        lowerCount += 1
    for ch in upperLetters:
        upperCount += 1
    for ch in digits:
        digitCount += 1
    else:
        nonAlphaCount += 1

You increase the variables without any condition you need to use all function for this job :

character = input("Enter a character: ")

lowerLetters = "abcdefghijklmnopqrstuvwxyz"
upperLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
digits = "0123456789"

if all(ch in character ckafor ch in lowerLetters):
    print(character, "is a lower case letter.")
elif all(ch in character for ch in upperLetters):
    print(character, "is an upper case letter.")
elif all(ch in characterfor ch in digits):
    print(character, "is a digit.")
else:
    print(character, "is a non-alphanumeric character.")

Now if you are looking for another way you can use regex for this task but is not as efficient as the preceding solutions.

character = input("Enter a character: ")
import re
if re.match(r'[a-z]+',characters):
        print(character, "is a lower case letter.")
elif re.match(r'[A-Z]',characters):
        print(character, "is an upper case letter.")
elif re.match(r'[0-9]+',characters):
        print(character, "is a digit.")
else:
        print(character, "is a non-alphanumeric character.")

Upvotes: 1

Psytho
Psytho

Reputation: 3384

Your code is good (though not the best one for your purpose even without using the methods you mentioned) but you have a couple of typos :) This is what you have:

for ch in character:
    for ch in lowerLetters:
        lowerCount += 1
    for ch in upperLetters:
        upperCount += 1
    for ch in digits:
        digitCount += 1
    else:
        nonAlphaCount += 1

And this is want you wanted to type:

for ch in character:
    if ch in lowerLetters:
        lowerCount += 1
    elif ch in upperLetters:
        upperCount += 1
    elif ch in digits:
        digitCount += 1
    else:
        nonAlphaCount += 1

Upvotes: 3

Ahasanul Haque
Ahasanul Haque

Reputation: 11134

You can use ascii value

Numbers 0-9 ASCII 48 to 57 
Lowercase letters a-z ASCII 97 to 122 
Uppercase letters A-Z ASCII 65-90

use ord function. like this:

>>ord('a')
97

So, to check if a is a lowercase letter or not, do:

if 97<=ord('a')<=122:
    print "lowercase character"

Upvotes: 4

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