Python String isalpha() Method

Python String isalpha() method is used to check whether all characters in the String is an alphabet.

Python String isalpha() Method Syntax:

Syntax:  string.isalpha()

Parameters: isalpha() does not take any parameters

Returns:

• True: If all characters in the string are alphabet.
• False: If the string contains 1 or more non-alphabets.

Errors and Exceptions:

1. It contains no arguments, therefore an error occurs if a parameter is passed
2. Both uppercase and lowercase alphabets return “True”
3. Space is not considered to be the alphabet, therefore it returns “False”

Python String isalpha() Method Example:

Python3

string = "geeks"
print(string.isalpha())

Output:

True

Example 1: Working of isalpha()

Python3

# checking for alphabets
string = 'Ayush'
print(string.isalpha())

string = 'Ayush0212'
print(string.isalpha())

# checking if space is an alphabet
string = 'Ayush Saxena'
print( string.isalpha())

Output:

True
False
False

Example 2: Practical Application

Given a string in Python, count the number of alphabets in the string and print the alphabets.

Input : string = 'Ayush Saxena'
Output : 11
         AyushSaxena

Input : string = 'Ayush0212'
Output : 5
         Ayush

Algorithm:

1. Initialize a new string and variable counter to 0. 
2. Traverse the given string character by character up to its length, check if the character is an alphabet. 
3. If it is an alphabet, increment the counter by 1 and add it to a new string, else traverse to the next character. 
4. Print the value of the counter and the new string.

Python3

# Given string
string='Ayush Saxena'
count=0

# Initialising new strings
newstring1 =""
newstring2 =""

# Iterating the string and checking for alphabets
# Incrementing the counter if an alphabet is found
# Finally printing the count
for a in string:
    if (a.isalpha()) == True:
        count+=1
        newstring1+=a
print(count)
print(newstring1)

# Given string
string='Ayush0212'
count=0
for a in string:
    if (a.isalpha()) == True:
        count+=1
        newstring2+=a
print(count)
print(newstring2)

Output: 

11
AyushSaxena
5
Ayush

Time Complexity: O(n)

Auxiliary Space: O(n)