Check if a String has alphabets

[Nikhil Das Nomula]

I have a string which contains numbers and characters or just numbers alone or characters alone and I want to check if it contains alphabets. I think we have to use regular expressions but I am not sure how do I go about with it.

[fred rosenberger]

What have you tried?

[Eoin Brosnan]

Nikhil Das Nomula wrote:I have a string which contains numbers and characters or just numbers alone or characters alone and I want to check if it contains alphabets. I think we have to use regular expressions but I am not sure how do I go about with it.

 
  Pattern p = Pattern.compile("[a-zA-Z]");
  Matcher m = p.matcher("AB 45");
    
  if(m.find())
    System.out.println("The string contains letters");

I am not clear on what pattern you want to match but the above is a starting point. [a-zA-Z] will match any letter, upper or lower.

[Nikhil Das Nomula]

@Fred rosenberger : I have tried iterating through each character but I wanted to use regular expressions.

@Eoin Brosnan: The characters can be at any place, they can be at the starting point, at the ending point or occur in the middle. Something like 989BR09 or 3988BR or SA3432DAS

[Rob Spoor]

And did you try that code with your input examples?

[Nikhil Das Nomula]

I tried that code but if we pass a string which has only number then it fails.

Pattern p = Pattern.compile("[a-zA-Z]");
Matcher m = p.matcher("3453443534534");

if(m.find())
System.out.println("contains letters");

Output:

contains letters

[fred rosenberger]

I am not a regex expert, but you may need a '+' on your pattern to say "one or more"

Pattern p = Pattern.compile("[a-zA-Z]+");

[Rob Spoor]

Nikhil Das Nomula wrote:Output:

contains letters

Odd. I just copy-pasted that code and get no output at all, as expected.

[Darryl Burke]

fred rosenberger wrote:I am not a regex expert, but you may need a '+' on your pattern to say "one or more"

Not for find(). You would for matches(), if you need to test that the whole String consists of characters [a-zA-Z]. To ascertain the presence of at least one alpha character using matches(), this will suffice.

".*[a-zA-Z].*"

[Nikhil Das Nomula]

@Rob Spoor: Here is the code that I tested with


public class RegularExpressionTest {
public static void main(String args[]){

Pattern p = Pattern.compile("[a-zA-Z]");
Matcher m = p.matcher("3453443VD534534");

if(m.find())
System.out.println("contains letters");
else{
System.out.println("no letters");
}
}
}

[Nikhil Das Nomula]

@Darryl Burke I tried doing that and it works !! Thanks a lot !

[Nikhil Das Nomula]

Just FYI here is the code that actually worked. Thanks to Darryl Burke

public class RegularExpressionTest {
	public static void main(String args[]){
		Pattern p = Pattern.compile(".*[a-zA-Z].*");
		  //Pattern p = Pattern.compile("[a-zA-Z]");  
		  Matcher m = p.matcher("AS3453443534534");  
		      
		  if(m.find())  
			  System.out.println("contains letters");
		  else{
			  System.out.println("no letters");
		  }
	}
}

[Aditya Jha]

The .* thing is not strictly needed when using find() (as opposed to match()).

This code works just fine:

	public static void main(String args[]) {
		Pattern p = Pattern.compile("[a-zA-Z]");
		Matcher m = p.matcher("3453443534534");

		if(m.find()){
			System.out.println("contains letters");
		}
		else{
			System.out.println("no letters");
		}

		return;
	}