Reputation: 7138

How to capitalize the first letter of word in a string using Java?

Example strings

one thousand only
two hundred
twenty
seven

How do I change the first character of a string in capital letter and not change the case of any of the other letters?

After the change it should be:

One thousand only
Two hundred
Twenty
Seven

Note: I don't want to use the apache.commons.lang.WordUtils to do this.

Upvotes: 237

Answers (24)

koppor

Reputation: 20501

Even for "simple" code, I would use libraries. The thing is not the code per se, but the already existing test cases covering exceptional cases. This could be null, empty strings, strings in other languages.

The word manipulation part has been moved out ouf Apache Commons Lang. It is now placed in Apache Commons Text. Get it via https://search.maven.org/artifact/org.apache.commons/commons-text.

You can use WordUtils.capitalize(String str) from Apache Commons Text. It is more powerful than you asked for. It can also capitalize fully (e.g., fixing "oNe tousand only").

Since it works on complete text, one has to tell it to capitalize only the first word.

WordUtils.capitalize("one thousand only", new char[0]);

Full JUnit class to enable playing with the functionality:

package io.github.koppor;

import org.apache.commons.text.WordUtils;
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.*;

class AppTest {

  @Test
  void test() {
    assertEquals("One thousand only", WordUtils.capitalize("one thousand only", new char[0]));
  }

}

Upvotes: 2

Saša

Reputation: 4798

Actually, you will get the best performance if you avoid + operator and use concat() in this case. It is the best option for merging just 2 strings (not so good for many strings though). In that case the code would look like this:

String output = input.substring(0, 1).toUpperCase().concat(input.substring(1));

Upvotes: 3

Bimlendu Kumar

Reputation: 346

class Test {
     public static void main(String[] args) {
        String newString="";
        String test="Hii lets cheCk for BEING String";  
        String[] splitString = test.split(" ");
        for(int i=0; i<splitString.length; i++){
            newString= newString+ splitString[i].substring(0,1).toUpperCase() 
                    + splitString[i].substring(1,splitString[i].length()).toLowerCase()+" ";
        }
        System.out.println("the new String is "+newString);
    }
 }

Upvotes: -1

attacomsian

Reputation: 2913

1. Using String's `substring()` Method

public static String capitalize(String str) {
    if(str== null || str.isEmpty()) {
        return str;
    }

    return str.substring(0, 1).toUpperCase() + str.substring(1);
}

Now just call the capitalize() method to convert the first letter of a string to uppercase:

System.out.println(capitalize("stackoverflow")); // Stackoverflow
System.out.println(capitalize("heLLo")); // HeLLo
System.out.println(capitalize(null)); // null

2. Apache Commons Lang

The StringUtils class from Commons Lang provides the capitalize() method that can also be used for this purpose:

System.out.println(StringUtils.capitalize("apache commons")); // Apache commons
System.out.println(StringUtils.capitalize("heLLO")); // HeLLO
System.out.println(StringUtils.uncapitalize(null)); // null

Add the following dependency to your pom.xml file (for Maven only):

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.9</version>
</dependency>

Here is an article that explains these two approaches in detail.

Upvotes: 1

Vimbai Chatitai

Reputation: 33

The following will give you the same consistent output regardless of the value of your inputString:

if(StringUtils.isNotBlank(inputString)) {
    inputString = StringUtils.capitalize(inputString.toLowerCase());
}

Upvotes: 1

Chris Halcrow

Reputation: 31940

Update July 2019

Currently, the most up-to-date library function for doing this is contained in org.apache.commons.lang3.StringUtils

import org.apache.commons.lang3.StringUtils;

StringUtils.capitalize(myString);

If you're using Maven, import the dependency in your pom.xml:

<dependency>
  <groupId>org.apache.commons</groupId>
  <artifactId>commons-lang3</artifactId>
  <version>3.9</version>
</dependency>

Upvotes: 1

Hardian

Reputation: 2022

I would like to add a NULL check and IndexOutOfBoundsException on the accepted answer.

String output = input.substring(0, 1).toUpperCase() + input.substring(1);

Java Code:

  class Main {
      public static void main(String[] args) {
        System.out.println("Capitalize first letter ");
        System.out.println("Normal  check #1      : ["+ captializeFirstLetter("one thousand only")+"]");
        System.out.println("Normal  check #2      : ["+ captializeFirstLetter("two hundred")+"]");
        System.out.println("Normal  check #3      : ["+ captializeFirstLetter("twenty")+"]");
        System.out.println("Normal  check #4      : ["+ captializeFirstLetter("seven")+"]");

        System.out.println("Single letter check   : ["+captializeFirstLetter("a")+"]");
        System.out.println("IndexOutOfBound check : ["+ captializeFirstLetter("")+"]");
        System.out.println("Null Check            : ["+ captializeFirstLetter(null)+"]");
      }

      static String captializeFirstLetter(String input){
             if(input!=null && input.length() >0){
                input = input.substring(0, 1).toUpperCase() + input.substring(1);
            }
            return input;
        }
    }

Output:

Normal  check #1      : [One thousand only]
Normal  check #2      : [Two hundred]
Normal  check #3      : [Twenty]
Normal  check #4      : [Seven]
Single letter check   : [A]
IndexOutOfBound check : []
Null Check            : [null]

Upvotes: 0

Takhir Atamuratov

Reputation: 159

public static String capitalize(String str){
        String[] inputWords = str.split(" ");
        String outputWords = "";
        for (String word : inputWords){
            if (!word.isEmpty()){
                outputWords = outputWords + " "+StringUtils.capitalize(word);
            }
        }
        return outputWords;
    }

Upvotes: 1

Aklesh Singh

Reputation: 973

My functional approach. its capstilise first character in sentence after whitescape in whole paragraph.

For capatilising only first character of the word just remove .split(" ")

           b.name.split(" ")
                 .filter { !it.isEmpty() }
                 .map { it.substring(0, 1).toUpperCase() 
                 +it.substring(1).toLowerCase() }
                  .joinToString(" ")

Upvotes: 1

Zhifan Cai

Reputation: 1

You can try the following code:

public string capitalize(str) {
    String[] array = str.split(" ");
    String newStr;
    for(int i = 0; i < array.length; i++) {
        newStr += array[i].substring(0,1).toUpperCase() + array[i].substring(1) + " ";
    }
    return newStr.trim();
}

Upvotes: 0

GVillani82

Reputation: 17429

Given the input string:

Character.toUpperCase(input.charAt(0)) + input.substring(1).toLowerCase()

Upvotes: 0

Jeff Padgett

Reputation: 2529

Adding everything together, it is a good idea to trim for extra white space at beginning of string. Otherwise, .substring(0,1).toUpperCase will try to capitalize a white space.

    public String capitalizeFirstLetter(String original) {
        if (original == null || original.length() == 0) {
            return original;
        }
        return original.trim().substring(0, 1).toUpperCase() + original.substring(1);
    }

Upvotes: 1

Jason Bierbrauer

Reputation: 23

Use this:

char[] chars = {Character.toUpperCase(A.charAt(0)), 
Character.toUpperCase(B.charAt(0))};
String a1 = chars[0] + A.substring(1);
String b1 = chars[1] + B.substring(1);

Upvotes: 0

Samet ÖZTOPRAK

Reputation: 3346

String sentence = "ToDAY   WeAthEr   GREat";    
public static String upperCaseWords(String sentence) {
        String words[] = sentence.replaceAll("\\s+", " ").trim().split(" ");
        String newSentence = "";
        for (String word : words) {
            for (int i = 0; i < word.length(); i++)
                newSentence = newSentence + ((i == 0) ? word.substring(i, i + 1).toUpperCase(): 
                    (i != word.length() - 1) ? word.substring(i, i + 1).toLowerCase() : word.substring(i, i + 1).toLowerCase().toLowerCase() + " ");
        }

        return newSentence;
    }
//Today Weather Great

Upvotes: 8

Vismay Hingwala

Reputation: 21

Its simple only one line code is needed for this. if String A = scanner.nextLine(); then you need to write this to display the string with this first letter capitalized.

System.out.println(A.substring(0, 1).toUpperCase() + A.substring(1));

And its done now.

Upvotes: 2

emanuel07

Reputation: 758

StringUtils.capitalize(str)

from apache commons-lang.

Upvotes: 7

Gene Bo

Reputation: 12063

Solution with StringBuilder:

value = new StringBuilder()
                .append(value.substring(0, 1).toUpperCase())
                .append(value.substring(1))
                .toString();

.. based on previous answers

Upvotes: 1

Ihor Rybak

Reputation: 3279

Also, There is org.springframework.util.StringUtils in Spring Framework:

StringUtils.capitalize(str);

Upvotes: 30

nada

Reputation: 11

Example using StringTokenizer class :

String st = "  hello all students";
String st1;
char f;
String fs="";
StringTokenizer a= new StringTokenizer(st);
while(a.hasMoreTokens()){   
        st1=a.nextToken();
        f=Character.toUpperCase(st1.charAt(0));
        fs+=f+ st1.substring(1);
        System.out.println(fs);
}

Upvotes: 1

Haseeb

Reputation: 1134

Simplest way is to use org.apache.commons.lang.StringUtils class

StringUtils.capitalize(Str);

Upvotes: 88

Anther

Reputation: 1844

public String capitalizeFirstLetter(String original) {
    if (original == null || original.length() == 0) {
        return original;
    }
    return original.substring(0, 1).toUpperCase() + original.substring(1);
}

Just... a complete solution, I see it kind of just ended up combining what everyone else ended up posting =P.

Upvotes: 91

Avantika

Reputation: 31

String s=t.getText().trim();
int l=s.length();
char c=Character.toUpperCase(s.charAt(0));
s=c+s.substring(1);
for(int i=1; i<l; i++)
    {
        if(s.charAt(i)==' ')
        {
            c=Character.toUpperCase(s.charAt(i+1));
            s=s.substring(0, i) + c + s.substring(i+2);
        }
    }
    t.setText(s);

Upvotes: 3

WhiteFang34

Reputation: 72039

If you only want to capitalize the first letter of a string named input and leave the rest alone:

String output = input.substring(0, 1).toUpperCase() + input.substring(1);

Now output will have what you want. Check that your input is at least one character long before using this, otherwise you'll get an exception.

Upvotes: 561

edgarmtze

Reputation: 25038

Here you go (hope this give you the idea):

/*************************************************************************
 *  Compilation:  javac Capitalize.java
 *  Execution:    java Capitalize < input.txt
 * 
 *  Read in a sequence of words from standard input and capitalize each
 *  one (make first letter uppercase; make rest lowercase).
 *
 *  % java Capitalize
 *  now is the time for all good 
 *  Now Is The Time For All Good 
 *  to be or not to be that is the question
 *  To Be Or Not To Be That Is The Question 
 *
 *  Remark: replace sequence of whitespace with a single space.
 *
 *************************************************************************/

public class Capitalize {

    public static String capitalize(String s) {
        if (s.length() == 0) return s;
        return s.substring(0, 1).toUpperCase() + s.substring(1).toLowerCase();
    }

    public static void main(String[] args) {
        while (!StdIn.isEmpty()) {
            String line = StdIn.readLine();
            String[] words = line.split("\\s");
            for (String s : words) {
                StdOut.print(capitalize(s) + " ");
            }
            StdOut.println();
        }
    }

}

Upvotes: 3

How to capitalize the first letter of word in a string using Java?

Answers (24)

1. Using String's substring() Method

2. Apache Commons Lang

Related Questions

1. Using String's `substring()` Method