How do i remove the whitespace? - java

I'm trying to create a palindrome tester program for my AP Java class and I need to remove the white spaces in my code completely but it's not letting me do so.
import java.util.Scanner;
public class Palin{
public static boolean isPalindrome(String stringToTest) {
String workingCopy = removeJunk(stringToTest);
String reversedCopy = reverse(workingCopy);
return reversedCopy.equalsIgnoreCase(workingCopy);
}
public static String removeJunk(String string) {
int i, len = string.length();
StringBuffer dest = new StringBuffer(len);
char c;
for (i = (len - 1); i >= 0; i-=1) {
c = string.charAt(i);
if (Character.isLetterOrDigit(c))
{
dest.append(c);
}
}
return dest.toString();
}
public static String reverse(String string) {
StringBuffer sb = new StringBuffer(string);
return sb.reverse().toString();
}
public static void main(String[] args) {
System.out.print("Enter Palindrome: ");
Scanner sc = new Scanner(System.in);
String string = sc.next();
String str = string;
String space = "";
String result = str.replaceAll("\\W", space);
System.out.println(result);
System.out.println();
System.out.println("Testing palindrome:");
System.out.println(" " + string);
System.out.println();
if (isPalindrome(result)) {
System.out.println("It's a palindrome!");
} else {
System.out.println("Not a palindrome!");
}
System.out.println();
}
}
Any help would be greatly appreciated.

Seems like your code is fine except for the following. You are using
String string = sc.next();
which will not read the whole line of input, hence you will lose part of the text. I think you should use the following instead of that line.
String string = sc.nextLine();

If you just want to remove the beginning and ending whitespace, you can use the built in function trim(), e.g. " abcd ".trim() is "abcd"
If you want to remove it everywhere, you can use the replaceAll() method with the whitespace class as the parameter, e.g. " abcd ".replaceAll("\W","").

Use a StringTokenizer to remove " "
StringTokenizer st = new StringTokenizer(string," ",false);
String t="";
while (st.hasMoreElements()) t += st.nextElement();
String result = t;
System.out.println(result);

I haven't actually tesed this, but have you considered the String.replaceAll(String regex, String replacement) method?
public static String removeJunk (String string) {
return string.replaceAll (" ", "");
}

Another thing to look out for is that while removing all non-digit/alpha characters removeJunk also reverses the string (it starts from the end and then appends one character at a time).
So after reversing it again (in reverse) you are left with the original and it will always claim that the given string is a palindrome.

You should use the String replace(char oldChar, char newChar) method.
Although the name suggests that only the first occurrence will be replaced, fact is that all occurrences will be replaced. The advantage of this method is that it won't use regular expressions, thus is more efficient.
So give a try to string.replace(' ', '');

Related

CamelCaser function in Java, problems with debugging

I am creating a CamelCase function in Java that takes a string this_is_a_sentence and returns ThisIsASentence My main problem comes with handeling the different characters in the string.
So far I have:
import java.util.Scanner;
public class Main{
public static String camelCaser(String str){
char[] strChr = str.toCharArray();
strChr[0] = strChr[0].toUpperCase;
for(int i = 0; i < strChr.length; i++){
if (strChr[i] == '_'){
strChr[i] = strChr[i+1].toUpperCase;
strChr[i+1] = "";
}
}
String newStr = new String(strChr);
return newStr;
}
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.println("String: ");
String str = input.next();
System.out.printf("Converting: %s into %s", str, camelCaser(str));
}
}
My main problems seems to be that you can not alter individual characters the same way that I am used to in C. I have read that you can use a class called Character but I cant figure out how to use it. The Java documentation on the matter https://docs.oracle.com/javase/7/docs/api/java/lang/Character.html did not help me either.
I changed around a bit of your logic to make this work. The easiest thing to make it work was to search the string for _, and then capitalize the following letter. After that, take the resulting string and remove all the _'s. It ended up like this:
import java.util.Scanner;
public class Caser{
public static String camelCaser(String str){
char[] strChr = str.toCharArray();
strChr[0] = Character.toUpperCase(strChr[0]);
for(int i = 0; i < strChr.length; i++) if (strChr[i] == '_') strChr[i+1] = Character.toUpperCase(strChr[i+1]);
String reply = new String(strChr);
reply = reply.replace("_", "");
return reply;
}
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.println("String: ");
String str = input.next();
System.out.printf("Converting: %s into %s", str, camelCaser(str));
}
}
EDIT:
What does String reply = new String(strChr); do?
This creates a new variable named reply. The variable is a String. new String(strChr) is a helper that the String class has whereby you can give it a char[] and it will automatically turn it into a String.
What does reply = reply.replace("_", ""); do?
.replace(String, String) is a String method that will search said string (in this case, reply) and will search for all instances of _ and when it finds them it will replace it with an empty String (in this case, it is blank "").
This code has several problems. First, toUpperCase() cannot be used on a char, you'd need to call Character.toUpperCase(character). Second, strChar[i+1]=""; does not compile, as "" is the empty String, strChar is a array of char.
I'd do something like this: first, I would split the string by "_" if you're sure you only want this as your separating character using String[] words = str.split("_"). Then, I would create a new String which will be the result String (let's call it res). After that, I would loop over all elements in words, make the first character upper case, add it to res and add all the other characters of the current element to res.
So, it would look like this:
public static String camelCaser(String str){
String[] words = str.split("_"); // split str by _
String res = ""; // result string
for(String word : words) {
// first check, if words is empty
if(!word.isEmpty()) {
// add first character upper case
res += Character.toUpperCase(word.charAt(0));
// add remaining characters as they are, if any
if(word.length() > 1) {
res += word.substring(1);
}
}
}
return res;
}
You would need to do something like Character.toUpperCase(strChr[0]); to convert a character in your array to uppercase.
Use Character.toUpperCase(char).
public class Main{
public static String camelCaser(String str){
char[] strChr = str.toCharArray();
strChr[0] = Character.toUpperCase(strChr[0]);
for(int i = 0; i < strChr.length; i++){
if (strChr[i] == '_'){
strChr[i] = Character.toUpperCase(strChr[i+1]);
strChr[i+1] = Character.valueOf('\u0000') ;
}
}
String newStr = new String(strChr);
return newStr;
}
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.println("String: ");
String str = input.next();
System.out.printf("Converting: %s into %s", str, camelCaser(str));
}
}

Remove characters at certain position at string

I want to remove certain characters at specific positions of the String. I have the positions, but I am facing problems removing the characters.
what i am doing is:
if (string.subSequence(k, k + 4).equals("\n\t\t\t")){
string = string.subSequence(0, k) + "" + s.subSequence(k, s.length());
}
I need to remove "\n\t\t\t" from string
Use StringBuilder:
StringBuilder sb = new StringBuilder(str);
sb.delete(start, end);
sb.deleteCharAt(index);
String result = sb.toString();
Use StringBuilder
String str=" ab a acd";
StringBuilder sb = new StringBuilder(str);
sb.delete(0,3);
sb.deleteCharAt(0);
String result = sb.toString();
System.out.println(result);
public static String remove(int postion, String stringName) {
char [] charArray = stringName.toCharArray();
char [] resultArray = new char[charArray.length];
int count = 0;
for (int i=0; i< charArray.length; i++) {
if (i != postion-1) {
resultArray[count] = charArray[i];
count++;
}
}
return String.valueOf(resultArray);
}
Use String.ReplaceAll() instead of this.
But if you only want to remove specific element only you can use substring().
Now you want to know position which you already know.
Put your points in a HashSet called set
StringBuilder sb=new StringBuilder();
for(int i=0;i<string.length();i++){
if(!set.contains(string.charAt(i)))
sb.append(string.charAt(i));
}
String reformattedString=sb.toString();
First you have to put \ in front of the special characters in order to do the matching of the two string, thus you will have .equals("\"\\n\\t\\t\\t\""), otherwise the substring is not going to be recognized inside the string. Then the other thing which you have to fix is the position of the index begin and end inside .subSequence(k,k+10) since the first and the last character are 10 positions apart and not 4. Note also that when you patch the string you go from position 0 to k and from k+10 to str.length(). If you go from 0 --> k and k --> length() you just join the old string together :).
Your code should work like this, I have tested it already
if(str.substring(k, k+10).equals("\"\\n\\t\\t\\t\""))
{
newstr = str.substring(0,k)+str.substring(k+10,(str.length()));
}
also you don't need +" "+ since you are adding strings. Whoever wants to see the effect of this can run this simple code:
public class ReplaceChars_20354310_part2 {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
String str = "This is a weird string containg balndbfhr frfrf br brbfbrf b\"\\n\\t\\t\\t\"";
System.out.println(str); //print str
System.out.println(ReplaceChars(str)); //then print after you replace the substring
System.out.println("\n"); //skip line
String str2 = "Whatever\"\\n\\t\\t\\t\"you want to put here"; //print str
System.out.println(str2); //then print after you replace the substring
System.out.println(ReplaceChars(str2));
}
//Method ReplaceChars
public static String ReplaceChars (String str) {
String newstr ="";
int k;
k = str.indexOf("\"\\n\\t\\t\\t\""); //position were the string starts within the larger string
if(str.substring(k, k+10).equals("\"\\n\\t\\t\\t\""))
{
newstr = str.substring(0,k)+str.substring(k+10,(str.length())); //or just str
}
return newstr;
}//end method
}

How to separate each word from a string in java?

One of my AP projects includes separating each word from a string, I have tried accomplishing numerous times yet with no success! My class has not yet learned about arrays, regex, or split yet so if you could help please avoid any of those. However we did learn substring, charAt, indexOf, length, trim ...
This is one of my attempts:
(notice that in order for me to actually notice I've split them I try adding N to the string I am re-creating, which is newWord)
public class Functions {
public static String stringReversal(String word){
if (word.length() <= 1){
return word;
}else{
char c = word.charAt(0);
return stringReversal(word.substring(1)) + c;
}
}
public static Boolean palindrome(String word){
Boolean palindrome;
if (word.equalsIgnoreCase(stringReversal(word))){
return palindrome = true;
} else{
return palindrome = false;
}
}
public static String pigLatin(String sentence){
if(sentence.length() <= 1){
return sentence;
} else {
String newWord = "";
return newWord += pigLatin(sentence.substring(0, sentence.indexOf(" "))) + " N ";
}
}
}
Main:
public class Main {
public static void main (String [] args){
Scanner in = new Scanner(System.in);
String word = in.nextLine();
System.out.println(Functions.test(word));
}
}
However the output only print N! Can anyone please help and show a way that I can accomplish this, I've tried many ideas yet none worked.
Since this seems to be highly homework-related, I will only post some hints and suggestions, you will have to combine my hints and suggestions to come up with the/a solution yourself.
I believe this:
sentence.indexOf("")
should be this: sentence.indexOf(" ")
Checking indexOf an empty string makes not much sense (it always returns zero, since the empty string can be found everywhere within a String).
public static void main(String[] args) {
String word = "a bit of words";
System.out.println(test(word));
}
public static String test(String sentence){
if(sentence.length() <= 1){
return sentence;
} else {
String newWord = "";
return newWord += test(sentence.substring(0, sentence.indexOf(" "))) + " N ";
}
}
The above prints: a N
However, if your input is only one word then sentence.indexOf(" ") will return -1. You will need to check this. Suggestion: Modify your if-statement to instead check if string contains a space character or not.
To solve the assignment, you will need some kind of loop (recursion can also be a kind of loop) to repeat a slightly modified process for each word. Hint: Fetch the first word, then fetch the original String except for the extracted word.
public static void main( String[] args )
{
Scanner in = new Scanner( System.in );
try
{
while( true )
{
String word = in.nextLine();
System.out.println( splitWords( word ) );
}
}
finally
{
in.close();
}
}
private static String splitWords( String s )
{
int splitIndex = s.indexOf( ' ' );
if( splitIndex >= 0 )
return s.substring( 0, splitIndex ) + " N " + splitWords( s.substring( splitIndex + 1 ) );
return s;
}
you can use standard method String#split()
String[] words = sentence.split(' ');
note than words is an array

Breaking Strings into chars that are in upper case

I'm making a method to read a whole class code and do some stuff with it.
What I want to do is get the name of the method, and make a String with it.
Something like removeProduct
I'll make a String "Remove Product"
How can I split the name method in capital cases?
How can I build this new string with the first letter of each word as capital case?
I'm doing it with substring, is there a easier and better way to do it?
ps: I'm sure my brazilian English didn't help on title. If anyone can make it looks better, I'd appreciate.
Don't bother reinvent the wheel, use the method in commons-lang
String input = "methodName";
String[] words = StringUtils.splitByCharacterTypeCamelCase(methodName);
String humanised = StringUtils.join(words, ' ');
You can use a regular expression to split the name into the various words, and then capitalize the first one:
public static void main(String[] args) {
String input = "removeProduct";
//split into words
String[] words = input.split("(?=[A-Z])");
words[0] = capitalizeFirstLetter(words[0]);
//join
StringBuilder builder = new StringBuilder();
for ( String s : words ) {
builder.append(s).append(" ");
}
System.out.println(builder.toString());
}
private static String capitalizeFirstLetter(String in) {
return in.substring(0, 1).toUpperCase() + in.substring(1);
}
Note that this needs better corner case handling, such as not appending a space at the end and handling 1-char words.
Edit: I meant to explain the regex. The regular expression (?=[A-Z]) is a zero-width assertion (positive lookahead) matching a position where the next character is between 'A' and 'Z'.
You can do this in 2 steps:
1 - Make the first letter of the string uppercase.
2 - Insert an space before an uppercase letter which is preceded by a lowercase letter.
For step 1 you can use a function and for step 2 you can use String.replaceAll method:
String str = "removeProduct";
str = capitalizeFirst(str);
str = str.replaceAll("(?<=[^A-Z])([A-Z])"," $1");
static String capitalizeFirst(String input) {
return input.substring(0, 1).toUpperCase() + input.substring(1);
}
Code In Action
#MrWiggles is right.
Just one more way to do this without being fancy :)
import java.util.StringTokenizer;
public class StringUtil {
public static String captilizeFirstLetter(String token) {
return Character.toUpperCase(token.charAt(0)) + token.substring(1);
}
public static String convert(String str) {
final StringTokenizer st = new StringTokenizer(str,
"A B C D E F G H I J K L M N O P Q R S T U V W X Y Z", true);
final StringBuilder sb = new StringBuilder();
String token;
if (st.hasMoreTokens()) {
token = st.nextToken();
sb.append(StringUtil.captilizeFirstLetter(token) + " ");
}
while (st.hasMoreTokens()) {
token = st.nextToken();
if (st.hasMoreTokens()) {
token = token + st.nextToken();
}
sb.append(StringUtil.captilizeFirstLetter(token) + " ");
}
return sb.toString().trim();
}
public static void main(String[] args) throws Exception {
String words = StringUtil.convert("helloWorldHowAreYou");
System.out.println(words);
}
}
public String convertMethodName(String methodName) {
StringBuilder sb = new StringBuilder().append(Character.toUpperCase(methodName.charAt(0)));
for (int i = 1; i < methodName.length(); i++) {
char c = methodName.charAt(i);
if (Character.isUpperCase(c)) {
sb.append(' ');
}
sb.append(c);
}
return sb.toString();
}
Handling it this way may give you some finer control in case you want to add in functionality later for other situations (multiple caps in a row, etc.). Basically, for each character, it just checks to see if it's within the bounds of capital letters (character codes 65-90, inclusive), and if so, adds a space to the buffer before the word begins.
EDIT: Using Character.isUpperCase()

How to capitalize the first character of each word in a string

Is there a function built into Java that capitalizes the first character of each word in a String, and does not affect the others?
Examples:
jon skeet -> Jon Skeet
miles o'Brien -> Miles O'Brien (B remains capital, this rules out Title Case)
old mcdonald -> Old Mcdonald*
*(Old McDonald would be find too, but I don't expect it to be THAT smart.)
A quick look at the Java String Documentation reveals only toUpperCase() and toLowerCase(), which of course do not provide the desired behavior. Naturally, Google results are dominated by those two functions. It seems like a wheel that must have been invented already, so it couldn't hurt to ask so I can use it in the future.
WordUtils.capitalize(str) (from apache commons-text)
(Note: if you need "fOO BAr" to become "Foo Bar", then use capitalizeFully(..) instead)
If you're only worried about the first letter of the first word being capitalized:
private String capitalize(final String line) {
return Character.toUpperCase(line.charAt(0)) + line.substring(1);
}
The following method converts all the letters into upper/lower case, depending on their position near a space or other special chars.
public static String capitalizeString(String string) {
char[] chars = string.toLowerCase().toCharArray();
boolean found = false;
for (int i = 0; i < chars.length; i++) {
if (!found && Character.isLetter(chars[i])) {
chars[i] = Character.toUpperCase(chars[i]);
found = true;
} else if (Character.isWhitespace(chars[i]) || chars[i]=='.' || chars[i]=='\'') { // You can add other chars here
found = false;
}
}
return String.valueOf(chars);
}
Try this very simple way
example givenString="ram is good boy"
public static String toTitleCase(String givenString) {
String[] arr = givenString.split(" ");
StringBuffer sb = new StringBuffer();
for (int i = 0; i < arr.length; i++) {
sb.append(Character.toUpperCase(arr[i].charAt(0)))
.append(arr[i].substring(1)).append(" ");
}
return sb.toString().trim();
}
Output will be: Ram Is Good Boy
I made a solution in Java 8 that is IMHO more readable.
public String firstLetterCapitalWithSingleSpace(final String words) {
return Stream.of(words.trim().split("\\s"))
.filter(word -> word.length() > 0)
.map(word -> word.substring(0, 1).toUpperCase() + word.substring(1))
.collect(Collectors.joining(" "));
}
The Gist for this solution can be found here: https://gist.github.com/Hylke1982/166a792313c5e2df9d31
String toBeCapped = "i want this sentence capitalized";
String[] tokens = toBeCapped.split("\\s");
toBeCapped = "";
for(int i = 0; i < tokens.length; i++){
char capLetter = Character.toUpperCase(tokens[i].charAt(0));
toBeCapped += " " + capLetter + tokens[i].substring(1);
}
toBeCapped = toBeCapped.trim();
I've written a small Class to capitalize all the words in a String.
Optional multiple delimiters, each one with its behavior (capitalize before, after, or both, to handle cases like O'Brian);
Optional Locale;
Don't breaks with Surrogate Pairs.
LIVE DEMO
Output:
====================================
SIMPLE USAGE
====================================
Source: cApItAlIzE this string after WHITE SPACES
Output: Capitalize This String After White Spaces
====================================
SINGLE CUSTOM-DELIMITER USAGE
====================================
Source: capitalize this string ONLY before'and''after'''APEX
Output: Capitalize this string only beforE'AnD''AfteR'''Apex
====================================
MULTIPLE CUSTOM-DELIMITER USAGE
====================================
Source: capitalize this string AFTER SPACES, BEFORE'APEX, and #AFTER AND BEFORE# NUMBER SIGN (#)
Output: Capitalize This String After Spaces, BeforE'apex, And #After And BeforE# Number Sign (#)
====================================
SIMPLE USAGE WITH CUSTOM LOCALE
====================================
Source: Uniforming the first and last vowels (different kind of 'i's) of the Turkish word D[İ]YARBAK[I]R (DİYARBAKIR)
Output: Uniforming The First And Last Vowels (different Kind Of 'i's) Of The Turkish Word D[i]yarbak[i]r (diyarbakir)
====================================
SIMPLE USAGE WITH A SURROGATE PAIR
====================================
Source: ab 𐐂c de à
Output: Ab 𐐪c De À
Note: first letter will always be capitalized (edit the source if you don't want that).
Please share your comments and help me to found bugs or to improve the code...
Code:
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Locale;
public class WordsCapitalizer {
public static String capitalizeEveryWord(String source) {
return capitalizeEveryWord(source,null,null);
}
public static String capitalizeEveryWord(String source, Locale locale) {
return capitalizeEveryWord(source,null,locale);
}
public static String capitalizeEveryWord(String source, List<Delimiter> delimiters, Locale locale) {
char[] chars;
if (delimiters == null || delimiters.size() == 0)
delimiters = getDefaultDelimiters();
// If Locale specified, i18n toLowerCase is executed, to handle specific behaviors (eg. Turkish dotted and dotless 'i')
if (locale!=null)
chars = source.toLowerCase(locale).toCharArray();
else
chars = source.toLowerCase().toCharArray();
// First charachter ALWAYS capitalized, if it is a Letter.
if (chars.length>0 && Character.isLetter(chars[0]) && !isSurrogate(chars[0])){
chars[0] = Character.toUpperCase(chars[0]);
}
for (int i = 0; i < chars.length; i++) {
if (!isSurrogate(chars[i]) && !Character.isLetter(chars[i])) {
// Current char is not a Letter; gonna check if it is a delimitrer.
for (Delimiter delimiter : delimiters){
if (delimiter.getDelimiter()==chars[i]){
// Delimiter found, applying rules...
if (delimiter.capitalizeBefore() && i>0
&& Character.isLetter(chars[i-1]) && !isSurrogate(chars[i-1]))
{ // previous character is a Letter and I have to capitalize it
chars[i-1] = Character.toUpperCase(chars[i-1]);
}
if (delimiter.capitalizeAfter() && i<chars.length-1
&& Character.isLetter(chars[i+1]) && !isSurrogate(chars[i+1]))
{ // next character is a Letter and I have to capitalize it
chars[i+1] = Character.toUpperCase(chars[i+1]);
}
break;
}
}
}
}
return String.valueOf(chars);
}
private static boolean isSurrogate(char chr){
// Check if the current character is part of an UTF-16 Surrogate Pair.
// Note: not validating the pair, just used to bypass (any found part of) it.
return (Character.isHighSurrogate(chr) || Character.isLowSurrogate(chr));
}
private static List<Delimiter> getDefaultDelimiters(){
// If no delimiter specified, "Capitalize after space" rule is set by default.
List<Delimiter> delimiters = new ArrayList<Delimiter>();
delimiters.add(new Delimiter(Behavior.CAPITALIZE_AFTER_MARKER, ' '));
return delimiters;
}
public static class Delimiter {
private Behavior behavior;
private char delimiter;
public Delimiter(Behavior behavior, char delimiter) {
super();
this.behavior = behavior;
this.delimiter = delimiter;
}
public boolean capitalizeBefore(){
return (behavior.equals(Behavior.CAPITALIZE_BEFORE_MARKER)
|| behavior.equals(Behavior.CAPITALIZE_BEFORE_AND_AFTER_MARKER));
}
public boolean capitalizeAfter(){
return (behavior.equals(Behavior.CAPITALIZE_AFTER_MARKER)
|| behavior.equals(Behavior.CAPITALIZE_BEFORE_AND_AFTER_MARKER));
}
public char getDelimiter() {
return delimiter;
}
}
public static enum Behavior {
CAPITALIZE_AFTER_MARKER(0),
CAPITALIZE_BEFORE_MARKER(1),
CAPITALIZE_BEFORE_AND_AFTER_MARKER(2);
private int value;
private Behavior(int value) {
this.value = value;
}
public int getValue() {
return value;
}
}
Using org.apache.commons.lang.StringUtils makes it very simple.
capitalizeStr = StringUtils.capitalize(str);
From Java 9+
you can use String::replaceAll like this :
public static void upperCaseAllFirstCharacter(String text) {
String regex = "\\b(.)(.*?)\\b";
String result = Pattern.compile(regex).matcher(text).replaceAll(
matche -> matche.group(1).toUpperCase() + matche.group(2)
);
System.out.println(result);
}
Example :
upperCaseAllFirstCharacter("hello this is Just a test");
Outputs
Hello This Is Just A Test
With this simple code:
String example="hello";
example=example.substring(0,1).toUpperCase()+example.substring(1, example.length());
System.out.println(example);
Result: Hello
I'm using the following function. I think it is faster in performance.
public static String capitalize(String text){
String c = (text != null)? text.trim() : "";
String[] words = c.split(" ");
String result = "";
for(String w : words){
result += (w.length() > 1? w.substring(0, 1).toUpperCase(Locale.US) + w.substring(1, w.length()).toLowerCase(Locale.US) : w) + " ";
}
return result.trim();
}
Use the Split method to split your string into words, then use the built in string functions to capitalize each word, then append together.
Pseudo-code (ish)
string = "the sentence you want to apply caps to";
words = string.split(" ")
string = ""
for(String w: words)
//This line is an easy way to capitalize a word
word = word.toUpperCase().replace(word.substring(1), word.substring(1).toLowerCase())
string += word
In the end string looks something like
"The Sentence You Want To Apply Caps To"
This might be useful if you need to capitalize titles. It capitalizes each substring delimited by " ", except for specified strings such as "a" or "the". I haven't ran it yet because it's late, should be fine though. Uses Apache Commons StringUtils.join() at one point. You can substitute it with a simple loop if you wish.
private static String capitalize(String string) {
if (string == null) return null;
String[] wordArray = string.split(" "); // Split string to analyze word by word.
int i = 0;
lowercase:
for (String word : wordArray) {
if (word != wordArray[0]) { // First word always in capital
String [] lowercaseWords = {"a", "an", "as", "and", "although", "at", "because", "but", "by", "for", "in", "nor", "of", "on", "or", "so", "the", "to", "up", "yet"};
for (String word2 : lowercaseWords) {
if (word.equals(word2)) {
wordArray[i] = word;
i++;
continue lowercase;
}
}
}
char[] characterArray = word.toCharArray();
characterArray[0] = Character.toTitleCase(characterArray[0]);
wordArray[i] = new String(characterArray);
i++;
}
return StringUtils.join(wordArray, " "); // Re-join string
}
public static String toTitleCase(String word){
return Character.toUpperCase(word.charAt(0)) + word.substring(1);
}
public static void main(String[] args){
String phrase = "this is to be title cased";
String[] splitPhrase = phrase.split(" ");
String result = "";
for(String word: splitPhrase){
result += toTitleCase(word) + " ";
}
System.out.println(result.trim());
}
1. Java 8 Streams
public static String capitalizeAll(String str) {
if (str == null || str.isEmpty()) {
return str;
}
return Arrays.stream(str.split("\\s+"))
.map(t -> t.substring(0, 1).toUpperCase() + t.substring(1))
.collect(Collectors.joining(" "));
}
Examples:
System.out.println(capitalizeAll("jon skeet")); // Jon Skeet
System.out.println(capitalizeAll("miles o'Brien")); // Miles O'Brien
System.out.println(capitalizeAll("old mcdonald")); // Old Mcdonald
System.out.println(capitalizeAll(null)); // null
For foo bAR to Foo Bar, replace the map() method with the following:
.map(t -> t.substring(0, 1).toUpperCase() + t.substring(1).toLowerCase())
2. String.replaceAll() (Java 9+)
ublic static String capitalizeAll(String str) {
if (str == null || str.isEmpty()) {
return str;
}
return Pattern.compile("\\b(.)(.*?)\\b")
.matcher(str)
.replaceAll(match -> match.group(1).toUpperCase() + match.group(2));
}
Examples:
System.out.println(capitalizeAll("12 ways to learn java")); // 12 Ways To Learn Java
System.out.println(capitalizeAll("i am atta")); // I Am Atta
System.out.println(capitalizeAll(null)); // null
3. Apache Commons Text
System.out.println(WordUtils.capitalize("love is everywhere")); // Love Is Everywhere
System.out.println(WordUtils.capitalize("sky, sky, blue sky!")); // Sky, Sky, Blue Sky!
System.out.println(WordUtils.capitalize(null)); // null
For titlecase:
System.out.println(WordUtils.capitalizeFully("fOO bAR")); // Foo Bar
System.out.println(WordUtils.capitalizeFully("sKy is BLUE!")); // Sky Is Blue!
For details, checkout this tutorial.
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the sentence : ");
try
{
String str = br.readLine();
char[] str1 = new char[str.length()];
for(int i=0; i<str.length(); i++)
{
str1[i] = Character.toLowerCase(str.charAt(i));
}
str1[0] = Character.toUpperCase(str1[0]);
for(int i=0;i<str.length();i++)
{
if(str1[i] == ' ')
{
str1[i+1] = Character.toUpperCase(str1[i+1]);
}
System.out.print(str1[i]);
}
}
catch(Exception e)
{
System.err.println("Error: " + e.getMessage());
}
I decided to add one more solution for capitalizing words in a string:
words are defined here as adjacent letter-or-digit characters;
surrogate pairs are provided as well;
the code has been optimized for performance; and
it is still compact.
Function:
public static String capitalize(String string) {
final int sl = string.length();
final StringBuilder sb = new StringBuilder(sl);
boolean lod = false;
for(int s = 0; s < sl; s++) {
final int cp = string.codePointAt(s);
sb.appendCodePoint(lod ? Character.toLowerCase(cp) : Character.toUpperCase(cp));
lod = Character.isLetterOrDigit(cp);
if(!Character.isBmpCodePoint(cp)) s++;
}
return sb.toString();
}
Example call:
System.out.println(capitalize("An à la carte StRiNg. Surrogate pairs: 𐐪𐐪."));
Result:
An À La Carte String. Surrogate Pairs: 𐐂𐐪.
Use:
String text = "jon skeet, miles o'brien, old mcdonald";
Pattern pattern = Pattern.compile("\\b([a-z])([\\w]*)");
Matcher matcher = pattern.matcher(text);
StringBuffer buffer = new StringBuffer();
while (matcher.find()) {
matcher.appendReplacement(buffer, matcher.group(1).toUpperCase() + matcher.group(2));
}
String capitalized = matcher.appendTail(buffer).toString();
System.out.println(capitalized);
There are many way to convert the first letter of the first word being capitalized. I have an idea. It's very simple:
public String capitalize(String str){
/* The first thing we do is remove whitespace from string */
String c = str.replaceAll("\\s+", " ");
String s = c.trim();
String l = "";
for(int i = 0; i < s.length(); i++){
if(i == 0){ /* Uppercase the first letter in strings */
l += s.toUpperCase().charAt(i);
i++; /* To i = i + 1 because we don't need to add
value i = 0 into string l */
}
l += s.charAt(i);
if(s.charAt(i) == 32){ /* If we meet whitespace (32 in ASCII Code is whitespace) */
l += s.toUpperCase().charAt(i+1); /* Uppercase the letter after whitespace */
i++; /* Yo i = i + 1 because we don't need to add
value whitespace into string l */
}
}
return l;
}
package com.test;
/**
* #author Prasanth Pillai
* #date 01-Feb-2012
* #description : Below is the test class details
*
* inputs a String from a user. Expect the String to contain spaces and alphanumeric characters only.
* capitalizes all first letters of the words in the given String.
* preserves all other characters (including spaces) in the String.
* displays the result to the user.
*
* Approach : I have followed a simple approach. However there are many string utilities available
* for the same purpose. Example : WordUtils.capitalize(str) (from apache commons-lang)
*
*/
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Test {
public static void main(String[] args) throws IOException{
System.out.println("Input String :\n");
InputStreamReader converter = new InputStreamReader(System.in);
BufferedReader in = new BufferedReader(converter);
String inputString = in.readLine();
int length = inputString.length();
StringBuffer newStr = new StringBuffer(0);
int i = 0;
int k = 0;
/* This is a simple approach
* step 1: scan through the input string
* step 2: capitalize the first letter of each word in string
* The integer k, is used as a value to determine whether the
* letter is the first letter in each word in the string.
*/
while( i < length){
if (Character.isLetter(inputString.charAt(i))){
if ( k == 0){
newStr = newStr.append(Character.toUpperCase(inputString.charAt(i)));
k = 2;
}//this else loop is to avoid repeatation of the first letter in output string
else {
newStr = newStr.append(inputString.charAt(i));
}
} // for the letters which are not first letter, simply append to the output string.
else {
newStr = newStr.append(inputString.charAt(i));
k=0;
}
i+=1;
}
System.out.println("new String ->"+newStr);
}
}
Here is a simple function
public static String capEachWord(String source){
String result = "";
String[] splitString = source.split(" ");
for(String target : splitString){
result += Character.toUpperCase(target.charAt(0))
+ target.substring(1) + " ";
}
return result.trim();
}
This is just another way of doing it:
private String capitalize(String line)
{
StringTokenizer token =new StringTokenizer(line);
String CapLine="";
while(token.hasMoreTokens())
{
String tok = token.nextToken().toString();
CapLine += Character.toUpperCase(tok.charAt(0))+ tok.substring(1)+" ";
}
return CapLine.substring(0,CapLine.length()-1);
}
Reusable method for intiCap:
public class YarlagaddaSireeshTest{
public static void main(String[] args) {
String FinalStringIs = "";
String testNames = "sireesh yarlagadda test";
String[] name = testNames.split("\\s");
for(String nameIs :name){
FinalStringIs += getIntiCapString(nameIs) + ",";
}
System.out.println("Final Result "+ FinalStringIs);
}
public static String getIntiCapString(String param) {
if(param != null && param.length()>0){
char[] charArray = param.toCharArray();
charArray[0] = Character.toUpperCase(charArray[0]);
return new String(charArray);
}
else {
return "";
}
}
}
Here is my solution.
I ran across this problem tonight and decided to search it. I found an answer by Neelam Singh that was almost there, so I decided to fix the issue (broke on empty strings) and caused a system crash.
The method you are looking for is named capString(String s) below.
It turns "It's only 5am here" into "It's Only 5am Here".
The code is pretty well commented, so enjoy.
package com.lincolnwdaniel.interactivestory.model;
public class StringS {
/**
* #param s is a string of any length, ideally only one word
* #return a capitalized string.
* only the first letter of the string is made to uppercase
*/
public static String capSingleWord(String s) {
if(s.isEmpty() || s.length()<2) {
return Character.toUpperCase(s.charAt(0))+"";
}
else {
return Character.toUpperCase(s.charAt(0)) + s.substring(1);
}
}
/**
*
* #param s is a string of any length
* #return a title cased string.
* All first letter of each word is made to uppercase
*/
public static String capString(String s) {
// Check if the string is empty, if it is, return it immediately
if(s.isEmpty()){
return s;
}
// Split string on space and create array of words
String[] arr = s.split(" ");
// Create a string buffer to hold the new capitalized string
StringBuffer sb = new StringBuffer();
// Check if the array is empty (would be caused by the passage of s as an empty string [i.g "" or " "],
// If it is, return the original string immediately
if( arr.length < 1 ){
return s;
}
for (int i = 0; i < arr.length; i++) {
sb.append(Character.toUpperCase(arr[i].charAt(0)))
.append(arr[i].substring(1)).append(" ");
}
return sb.toString().trim();
}
}
Here we go for perfect first char capitalization of word
public static void main(String[] args) {
String input ="my name is ranjan";
String[] inputArr = input.split(" ");
for(String word : inputArr) {
System.out.println(word.substring(0, 1).toUpperCase()+word.substring(1,word.length()));
}
}
}
//Output : My Name Is Ranjan
For those of you using Velocity in your MVC, you can use the capitalizeFirstLetter() method from the StringUtils class.
String s="hi dude i want apple";
s = s.replaceAll("\\s+"," ");
String[] split = s.split(" ");
s="";
for (int i = 0; i < split.length; i++) {
split[i]=Character.toUpperCase(split[i].charAt(0))+split[i].substring(1);
s+=split[i]+" ";
System.out.println(split[i]);
}
System.out.println(s);
package corejava.string.intern;
import java.io.DataInputStream;
import java.util.ArrayList;
/*
* wap to accept only 3 sentences and convert first character of each word into upper case
*/
public class Accept3Lines_FirstCharUppercase {
static String line;
static String words[];
static ArrayList<String> list=new ArrayList<String>();
/**
* #param args
*/
public static void main(String[] args) throws java.lang.Exception{
DataInputStream read=new DataInputStream(System.in);
System.out.println("Enter only three sentences");
int i=0;
while((line=read.readLine())!=null){
method(line); //main logic of the code
if((i++)==2){
break;
}
}
display();
System.out.println("\n End of the program");
}
/*
* this will display all the elements in an array
*/
public static void display(){
for(String display:list){
System.out.println(display);
}
}
/*
* this divide the line of string into words
* and first char of the each word is converted to upper case
* and to an array list
*/
public static void method(String lineParam){
words=line.split("\\s");
for(String s:words){
String result=s.substring(0,1).toUpperCase()+s.substring(1);
list.add(result);
}
}
}
If you prefer Guava...
String myString = ...;
String capWords = Joiner.on(' ').join(Iterables.transform(Splitter.on(' ').omitEmptyStrings().split(myString), new Function<String, String>() {
public String apply(String input) {
return Character.toUpperCase(input.charAt(0)) + input.substring(1);
}
}));
String toUpperCaseFirstLetterOnly(String str) {
String[] words = str.split(" ");
StringBuilder ret = new StringBuilder();
for(int i = 0; i < words.length; i++) {
ret.append(Character.toUpperCase(words[i].charAt(0)));
ret.append(words[i].substring(1));
if(i < words.length - 1) {
ret.append(' ');
}
}
return ret.toString();
}

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