



Check if a string contains only alphabets in Java using Lambda expression


Given a String, the task is to check whether a string contains only alphabets or not.
Examples:


Input : GeeksforGeeks

Output : True



Input : Geeks4Geeks

Output : False



Input : null

Output : False



Recommended: Please try your approach on {IDE} first, before moving on to the solution.

The idea is to use isLetter() method of Character class. 
Algorithm:

Get the string
Match the string:

Check if the string is empty or not. If empty, return false
Check if the string is null or not. If null, return false.
If the string is neither empty nor null,
then check using Lambda Expression Character::isLetter().


Return true if matched

Pseudocode:








 


 

 













public static boolean isStringOnlyAlphabet(String str) 
{ 
    return ((!str.equals("")) 
            && (str != null) 
            && (str.chars().allMatch(Character::isLetter))); 
} 



















Program: Checking if String contains only Alphabets.







 


 

 













// Java program to check if String contains only Alphabets 
// using Lambda Expression 
  
class GFG { 
  
    // Function to check String for only Alphabets 
    public static boolean isStringOnlyAlphabet(String str) 
    { 
        return ((str != null) 
                && (!str.equals("")) 
                && (str.chars().allMatch(Character::isLetter))); 
    } 
  
    // Main method 
    public static void main(String[] args) 
    { 
  
        // Checking for True case 
        System.out.println("Test Case 1:"); 
  
        String str1 = "GeeksforGeeks"; 
        System.out.println("Input: " + str1); 
        System.out.println("Output: " + isStringOnlyAlphabet(str1)); 
  
        // Checking for String with numeric characters 
        System.out.println("\nTest Case 2:"); 
  
        String str2 = "Geeks4Geeks"; 
        System.out.println("Input: " + str2); 
        System.out.println("Output: " + isStringOnlyAlphabet(str2)); 
  
        // Checking for null String 
        System.out.println("\nTest Case 3:"); 
  
        String str3 = null; 
        System.out.println("Input: " + str3); 
        System.out.println("Output: " + isStringOnlyAlphabet(str3)); 
  
        // Checking for empty String 
        System.out.println("\nTest Case 4:"); 
  
        String str4 = ""; 
        System.out.println("Input: " + str4); 
        System.out.println("Output: " + isStringOnlyAlphabet(str4)); 
    } 
} 



















Output:


Test Case 1:

Input: GeeksforGeeks

Output: true



Test Case 2:

Input: Geeks4Geeks

Output: false



Test Case 3:

Input: null

Output: false



Test Case 4:

Input: 

Output: false



Check if a string contains only alphabets in Java using ASCII values
Check if a string contains only alphabets in Java using Regex





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