CODEWITHSUNDEEP
javastring
Tommy Barrett
Tommy Barrett

Reputation: 61

test to see if string contains 2 letters followed by 7 numbers

I need to error check String licenseNumber which is supposed to contain 2 letters followed by 7 digits within the String. I'm very new to Java and am in the early stages of classes so all help would be appreciated. I only need to return a true or false.

I'm not sure if there is a way to use loops to check the String or if there is a smarter way.

Upvotes: 2

Views: 2552

Answers (3)

xenteros
xenteros

Reputation: 15852

The correct regex will be ^.*[a-zA-Z]{2}[0-9]{7}.*$

String pattern = "^.*[a-zA-Z]{2}[0-9]{7}.*$";
System.out.println( "aa1234567".matches(pattern) ); // true
System.out.println( "aa123456".matches(pattern) ); // false
System.out.println( "aaa12345678".matches(pattern) ); // true

Upvotes: 1

ItamarG3
ItamarG3

Reputation: 4122

Here's a very straight-forward and rather simple way. This would work for your specific issue (but for any license number that follows the description in your answer)

Well, say you have a string

String str = "ab1234567";

then you can get a char array:

char[] characters = str.toCharacterArray();

and then check if it is the right length:

boolean isValid = true;
if(characters.length==9){
    if((96<characters[0]<123 && 96<characters[1]<123) || (64<characters[0]<91&& 64<characters[1]<91)){//this checks if the first two characters are lowercase letters
        for(int i = 2; i< characters.length; i++){
            if(!(47<characters[i]<58)){//this checks if the rest are numbers.
                isValid = false;
            }
        }
     }else{
         isValid = false;
     }
 }else{
     isValid = false;
 }

and then if isValid is true in the end, then your string is a license plate.

Upvotes: -1

guenhter
guenhter

Reputation: 12177

Use regular expressions:

String pattern = "^[a-zA-Z]{2}[0-9]{7}$";
System.out.println( "aa1234567".matches(pattern) ); // true
System.out.println( "aa123456".matches(pattern) ); // false

boolean verifyLicense = licenseNumber.matches(pattern);
...

Upvotes: 2

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