Java string start with letter

Java String startsWith() Method with examples

The startsWith() method of String class is used for checking prefix of a String. It returns a boolean value true or false based on whether the given string starts with the specified letter or word.

For example:

String str = "Hello"; //This will return true because string str starts with "He" str.startsWith("He");

Java String startsWith() method Examples

There are two variations of starsWith() method.

boolean startsWith(String str) : It returns true if the String str is a prefix of the String.

boolean startsWith(String str, index fromIndex) : It returns true if the String begins with str, it starts looking from the specified index “fromIndex”.

For example lets say that the value of the String str is “Hi there” and we are calling starsWith() method like this – str.startsWith(“there”, 3) then this will return true because we have provided the fromIndex value as 3. The method will start looking from index 3 and it will find the string from where it starts searching.

Example 1: Checking prefix without fromIndex

This is a simple example where we have a string s and we are checking wether the string s starts with a particular word using startsWith() method.

Output:

Example 2: Checking prefix starting from an index

Let’s take an example where we are using both the variations of startsWith() method. As you can see that when we provided the fromIndex, the output changed. This is because it starts looking from the specified fromIndex.

• If str.startsWith(«brown») then it is checking the prefix of this string: quick brown fox jumps over the lazy dog
• If str.StartsWith(«brown», 6) then it is checking the prefix of this string: brown fox jumps over the lazy dog

public class StartsWithExample < public static void main(String args[]) < String str= new String("quick brown fox jumps over the lazy dog"); System.out.println("String str starts with quick: "+str.startsWith("quick")); System.out.println("String str starts with brown: "+str.startsWith("brown")); System.out.println("substring of str(starting from 6th index) has brown prefix: " +str.startsWith("brown", 6)); System.out.println("substring of str(starting from 6th index) has quick prefix: " +str.startsWith("quick", 6)); >>

String str starts with quick: true String str starts with brown: false substring of str(starting from 6th index) has brown prefix: true substring of str(starting from 6th index) has quick prefix: false

Example 3: Whether String starts with an empty string

An empty string is often referred as “” (no space between double quotes). We are checking whether every string has empty string as a prefix. We can simply check this by calling startsWith() method like this: str.startsWith(«») .

public class JavaExample < public static void main(String args[]) < String str = "Welcome to BeginnersBook"; // "" represents an empty string if(str.startsWith(""))< System.out.println("String has empty string as prefix"); >else < System.out.println("String doesn't have empty string as prefix"); >> >

String has empty string as prefix

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Check if string starts with letter java

Solution 1: If you want to avoid possible locale issues, you can give two ranges, one for lower case and one for upper case: Solution 2: I would put this in new method: And then use it: Solution 3: As others have mentioned, this is clearly the case where regular expressions should be used: Solution 1: Try this. You need to use String::matches as shown below: A sample run: Solution 3: See this REGEX start with one or more digits and ends with one or more upper character Solution 1: You can use: Solution 2: Use a character class: Solution 3: Or simply use shortcut it’s mean in java You can also change to if you want check the start of the string and not the start of the line

Java / startsWith more than one letter?

char first = Character.toLowerCase(str.charAt(0)); if (first >= 'a' && first 

If you want to avoid possible locale issues, you can give two ranges, one for lower case and one for upper case:

char first = str.charAt(0); if ((first >= 'a' && first = 'A' && first 

I would put this in new method:

private boolean myStartsWith(String. args) < for(String str : args) < if(args.startsWith(str) < return true; >> return false; > 

str.myStartsWith(new String[]); 

As others have mentioned, this is clearly the case where regular expressions should be used:

java.util.regex.Pattern p = java.util.regex.Pattern.compile("^[a-cA-C]"); java.util.regex.Matcher m = p.matcher(alpha); // if (m.matches()) < . 

Check if string starts or ends with specific letter, Then you could do: String[] values = input.split(" "); if(values[1].equals("A")) < // Code for A. >Use regex to capture different groups. The

Checking if the input starts with a number and ends with an Upper letter

Try this. Due to their overhead I try to avoid using regular expressions unless it really simplifies the task. In this case there are methods that facilitate the process.

In addition, white space at the beginning and end of the sentence affects the result (i.e. is not trimmed).

 int lastIdx = sentence.length()-1; if (Character.isDigit(sentence.charAt(0)) && sentence.contains("end") && Character.isUpperCase(sentence.charAt(lastIdx)))

Your code didn't work because String::startWith doesn't take a regex as a parameter while you are using a regex. You need to use String::matches as shown below:

import java.util.Scanner; public class Main < public static void main(String[] args) < Scanner scan = new Scanner(System.in); int no = 0; while (no < 4) < System.out.print("Type a number >4: "); no = Integer.parseInt(scan.nextLine()); > String sentence; int y = 0; for (int i = 0; i < no; i++) < System.out.print("Enter a sentence: "); sentence = scan.nextLine(); if (sentence.matches("9+.*end.*[\\p]")) < y++; >> System.out.println(y); > > 

A sample run:

Type a number >4: 5 Enter a sentence: Hello world Enter a sentence: 123 Hello World ends with LD Enter a sentence: 123HelloendHH Enter a sentence: Good morning Enter a sentence: 123Good morning 2 

See this REGEX (^4+)(end)([A-Z]+$) start with one or more digits and ends with one or more upper character

 if (sentence.matches("(^7+)(end)([A-Z]+$)")) < y++; >System.out.println(y); 

Java String startsWith() method, The Java String class startsWith() method checks if this string starts with the given prefix. It returns true if this string starts with the given prefix;

How to check if string starts with a number, latin letter or underscore

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Java String startsWith()

Java String.startsWith() method checks if a string begins with the specified prefix substring. The argument prefix must be a standard substring, the regular expressions are not supported.

The startsWith() method is an overloaded method and has two forms:

• boolean startsWith(substring) – returns true if the substring is a prefix of the String.
• boolean startsWith(substring, fromIndex) – returns true if the String begins with substring starting from the specified index fromIndex .

2. String.startsWith(substring) Example

The following Java program checks if a string starts with the specified prefixes.

String blogName = "howtodoinjava.com"; Assertions.assertTrue(blogName.startsWith("how")); Assertions.assertTrue(blogName.startsWith("howto")); Assertions.assertFalse(blogName.startsWith("hello"));

2.1. Regular Expressions are Not Supported

Note that the startsWith() does not support regular expressions as an argument. If we pass the regex as an argument, it will only be treated as a normal string.

String blogName = "howtodoinjava.com"; Assertions.assertFalse(blogName.startsWith("^h")); 

If you want to check the prefix with regular expressions, then you can use the Pattern and Matcher API.

Please note that null is not allowed as a method argument. The method will throw NullPointerException if null is passed.

Assertions.assertThrows(NullPointerException.class, () -> < blogName.startsWith(null); >);

3. String.startsWith(substring, fromIndex) Example

The startsWith(substring, fromIndex) also checks for substring prefix but the difference is that it checks the prefix beginning at the specified index position using fromIndex .

This method also does not accept null argument.

String blogName = "howtodoinjava.com"; Assertions.assertTrue(blogName.startsWith("h", 0)); Assertions.assertFalse(blogName.startsWith("do", 0)); Assertions.assertTrue(blogName.startsWith("do", 5));

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