ascii_letters in Python

In Python3, ascii_letters is a pre-initialized string used as string constant.
ascii_letters is basically concatenation of ascii_lowercase and ascii_uppercase string constants. Also, the value generated is not locale-dependent, hence, doesn’t change.

Syntax :

string.ascii_letters

Note : Make sure to import string library function inorder to use ascii_letters.

Parameters :

 Doesn't take any parameter, since it's not a function. 

Returns :

 Return all ASCII letters (both lower and upper case)

Code #1 :

# import string library function
import string

# Storing the value in variable result
result = string.ascii_letters

# Printing the value
print(result)

Output :

abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ

Code #2 :
Given code checks if the string input has only ASCII characters or not.

# importing string library function
import string

# Function checks if input string
# has only ascii letters or not
def check(value):
    for letter in value:

        # If anything other than ascii
        # letter is present, then return
        # False, else return True
        if letter not in string.ascii_letters:
            return False
    return True

# Driver Code
input1 = "GeeksForGeeks"
print(input1, "--> ",  check(input1))

input2 = "Geeks for Geeks"
print(input2, "--> ", check(input2))

input3 = "Geeks_for_geeks"
print(input3, "--> ", check(input3))

Output :

GeeksForGeeks -->  True
Geeks for Geeks -->  False
Geeks_for_geeks -->  False

Applications :
The string constant ascii_letters can be used in many practical applications.
Let’s see a code explaining how to use ascii_letters to generate strong random passwords of given size.

Code #1 :

# Importing random to generate
# random string sequence
import random

# Importing string library function
import string

def rand_pass(size):

    # Takes random choices from
    # ascii_letters and digits
    generate_pass = ''.join([random.choice(
                        string.ascii_letters + string.digits)
                        for n in range(size)])

    return generate_pass

# Driver Code
password = rand_pass(10)
print(password)

Output :

oQjI5MOXQ3

Note : Above given code will print random (different) password everytime, for the size provided.

Code #2 :
Say if you want to generate random password, but from the set of given string. Let’s see how can we do this using ascii_letters :

# Importing random to generate
# random string sequence
import random

# Importing string library function
import string

def rand_pass(size, scope = string.ascii_letters + string.digits):

    # Takes random choices from ascii_letters and digits
    generate_pass = ''.join([random.choice(scope)
                             for n in range(size)])

    return generate_pass

# Driver Code
password = rand_pass(10, 'Geeks3F0rgeeKs')
print(password)

Output :

kg3g03keG3