CODEWITHSUNDEEP
javawhitespace
zyamat
zyamat

Reputation: 8481

Removing whitespace from strings in Java

I have a string like this: 

mysz = "name=john age=13 year=2001";

I want to remove the whitespaces in the string. I tried trim() but this removes only whitespaces before and after the whole string. I also tried replaceAll("\\W", "") but then the = also gets removed.

How can I achieve a string with:

mysz2 = "name=johnage=13year=2001"

Upvotes: 846

Views: 1716275

Answers (30)

masikkk
masikkk

Reputation: 51

use StrUtil.cleanBlank(CharSequence str) by hutool

<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.8.16</version>
</dependency>

Upvotes: 0

Pranshu Singh
Pranshu Singh

Reputation: 71

You can achieve this without using replaceAll() or any Predefined Method in Java. this way is preferred:-

public class RemoveSpacesFromString {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String newString;
        String str = "prashant is good" ;
        int i;
        char[] strArray = str.toCharArray();
        StringBuffer sb =  new StringBuffer();
        
        for(i = 0; i < strArray.length; i++)
        {
            if(strArray[i] != ' ' && strArray[i] != '\t')
            {
                sb.append(strArray[i]);
            }
        }
        System.out.println(sb);
    }
}

Upvotes: -2

Siva Sanjay Acchana
Siva Sanjay Acchana

Reputation: 117

package com.sanjayacchana.challangingprograms;

public class RemoveAllWhiteSpacesInString {

    public static void main(String[] args) {
        
        String str = "name=john age=13 year=2001";
        
        str = str.replaceAll("\\s", ""); 
        
        System.out.println(str);
        
        
    }

}

Upvotes: 2

Varejones
Varejones

Reputation: 703

You should use

s.replaceAll("\\s+", "");

instead of:

s.replaceAll("\\s", "");

This way, it will work with more than one spaces between each string. The + sign in the above regex means "one or more \s"

--\s = Anything that is a space character (including space, tab characters etc). Why do we need s+ here?

Upvotes: 57

Stian Standahl
Stian Standahl

Reputation: 2619

I am trying an aggregation answer where I test all ways of removing all whitespaces in a string. Each method is ran 1 million times and then then the average is taken. Note: Some compute will be used on summing up all the runs.

Results:

1st place from @jahir 's answer

  • StringUtils with short text: 1.21E-4 ms (121.0 ms)
  • StringUtils with long text: 0.001648 ms (1648.0 ms)

2nd place

  • String builder with short text: 2.48E-4 ms (248.0 ms)
  • String builder with long text: 0.00566 ms (5660.0 ms)

3rd place

  • Regex with short text: 8.36E-4 ms (836.0 ms)
  • Regex with long text: 0.008877 ms (8877.0 ms)

4th place

  • For loop with short text: 0.001666 ms (1666.0 ms)
  • For loop with long text: 0.086437 ms (86437.0 ms)

Here is the code:

public class RemoveAllWhitespaces {
    public static String Regex(String text){
        return text.replaceAll("\\s+", "");
    }

    public static String ForLoop(String text) {
        for (int i = text.length() - 1; i >= 0; i--) {
            if(Character.isWhitespace(text.codePointAt(i))) {
                text = text.substring(0, i) + text.substring(i + 1);
            }
        }

        return text;
    }

    public static String StringBuilder(String text){
        StringBuilder builder = new StringBuilder(text);
        for (int i = text.length() - 1; i >= 0; i--) {
            if(Character.isWhitespace(text.codePointAt(i))) {
                builder.deleteCharAt(i);
            }
        }

        return builder.toString();
    }
}

Here are the tests:

import org.junit.jupiter.api.Test;

import java.util.function.Function;
import java.util.stream.IntStream;

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

public class RemoveAllWhitespacesTest {
    private static final String longText = "123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222123 123 \t 1adc \n 222";
    private static final String expected = "1231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc2221231231adc222";

    private static final String shortText = "123 123 \t 1adc \n 222";
    private static final String expectedShortText = "1231231adc222";

    private static final int numberOfIterations = 1000000;

    @Test
    public void Regex_LongText(){
        RunTest("Regex_LongText", text -> RemoveAllWhitespaces.Regex(text), longText, expected);
    }

    @Test
    public void Regex_ShortText(){
        RunTest("Regex_LongText", text -> RemoveAllWhitespaces.Regex(text), shortText, expectedShortText);

    }

    @Test
    public void For_LongText(){
        RunTest("For_LongText", text -> RemoveAllWhitespaces.ForLoop(text), longText, expected);
    }

    @Test
    public void For_ShortText(){
        RunTest("For_LongText", text -> RemoveAllWhitespaces.ForLoop(text), shortText, expectedShortText);
    }

    @Test
    public void StringBuilder_LongText(){
        RunTest("StringBuilder_LongText", text -> RemoveAllWhitespaces.StringBuilder(text), longText, expected);
    }

    @Test
    public void StringBuilder_ShortText(){
        RunTest("StringBuilder_ShortText", text -> RemoveAllWhitespaces.StringBuilder(text), shortText, expectedShortText);
    }

    private void RunTest(String testName, Function<String,String> func, String input, String expected){
        long startTime = System.currentTimeMillis();
        IntStream.range(0, numberOfIterations)
                .forEach(x -> assertEquals(expected, func.apply(input)));
        double totalMilliseconds = (double)System.currentTimeMillis() - (double)startTime;
        System.out.println(
                String.format(
                        "%s: %s ms (%s ms)",
                        testName,
                        totalMilliseconds / (double)numberOfIterations,
                        totalMilliseconds
                )
        );
    }
}

Upvotes: 6

Kunal Vohra
Kunal Vohra

Reputation: 2836

Quite a lot of answers are provided. I would like to give a solution which is quite readable and better than regex.

import java.io.IOException;

import org.apache.commons.lang.StringUtils;

public class RemoveAllWhitespaceTest {

    public static void main(String[] args) throws IOException {

        String str1 = "\n\tThis is my string \n \r\n  !";

        System.out.println("[" + str1 + "]");

        System.out.println("Whitespace Removed:");

        System.out.println("[" + StringUtils.deleteWhitespace(str1) + "]");

        System.out.println();

    }

}

Upvotes: -1

Abd Abughazaleh
Abd Abughazaleh

Reputation: 5495

private String generateAttachName(String fileName, String searchOn, String char1) {
    return fileName.replaceAll(searchOn, char1);
}


String fileName= generateAttachName("Hello My Mom","\\s","");

Upvotes: -1

Deb
Deb

Reputation: 663

You can also take a look at the below Java code. Following codes does not use any "built-in" methods.

/**
 * Remove all characters from an alphanumeric string.
 */
public class RemoveCharFromAlphanumerics {

    public static void main(String[] args) {

        String inp = "01239Debashish123Pattn456aik";

        char[] out = inp.toCharArray();

        int totint=0;

        for (int i = 0; i < out.length; i++) {
            System.out.println(out[i] + " : " + (int) out[i]);
            if ((int) out[i] >= 65 && (int) out[i] <= 122) {
                out[i] = ' ';
            }
            else {
                totint+=1;
            }

        }

        System.out.println(String.valueOf(out));
        System.out.println(String.valueOf("Length: "+ out.length));

        for (int c=0; c<out.length; c++){

            System.out.println(out[c] + " : " + (int) out[c]);

            if ( (int) out[c] == 32) {
                System.out.println("Its Blank");
                 out[c] = '\'';
            }

        }

        System.out.println(String.valueOf(out));

        System.out.println("**********");
        System.out.println("**********");
        char[] whitespace = new char[totint];
        int t=0;
        for (int d=0; d< out.length; d++) {

            int fst =32;



            if ((int) out[d] >= 48 && (int) out[d] <=57 ) {

                System.out.println(out[d]);
                whitespace[t]= out[d];
                t+=1;

            }

        }

        System.out.println("**********");
        System.out.println("**********");

        System.out.println("The String is: " + String.valueOf(whitespace));

    }
}

Input:

String inp = "01239Debashish123Pattn456aik";

Output:

The String is: 01239123456

Upvotes: -1

DEVNAG BHARAD
DEVNAG BHARAD

Reputation: 114

Try this:

String str="name=john age=13 year=2001";
String s[]=str.split(" ");
StringBuilder v=new StringBuilder();
for (String string : s) {
    v.append(string);
}
str=v.toString();

Upvotes: -6

Rajesh Gurbani
Rajesh Gurbani

Reputation: 211

public static String removeWhiteSpaces(String str){
    String s = "";
    char[] arr = str.toCharArray();
    for (int i = 0; i < arr.length; i++) {
        int temp = arr[i];
        if(temp != 32 && temp != 9) { // 32 ASCII for space and 9 is for Tab
            s += arr[i];
        }
    }
    return s;
}

This might help.

Upvotes: -1

user9832813
user9832813

Reputation: 115

Separate each group of text into its own substring and then concatenate those substrings:

public Address(String street, String city, String state, String zip ) {
    this.street = street;
    this.city = city;
    // Now checking to make sure that state has no spaces...
    int position = state.indexOf(" ");
    if(position >=0) {
        //now putting state back together if it has spaces...
        state = state.substring(0, position) + state.substring(position + 1);  
    }
}

Upvotes: -1

Jemshit
Jemshit

Reputation: 10038

When using st.replaceAll("\\s+","") in Kotlin, make sure you wrap "\\s+" with Regex:

"myString".replace(Regex("\\s+"), "")

Upvotes: 4

Rakesh Chaudhari
Rakesh Chaudhari

Reputation: 3502

There are others space char too exists in strings.. So space char we may need to replace from strings.

Ex: NO-BREAK SPACE, THREE-PER-EM SPACE, PUNCTUATION SPACE

Here is the list of space char http://jkorpela.fi/chars/spaces.html

So we need to modify

\u2004 us for THREE-PER-EM SPACE

s.replaceAll("[\u0020\u2004]","")

Upvotes: 1

Abdur Rahman
Abdur Rahman

Reputation: 1656

White space can remove using isWhitespace function from Character Class.

public static void main(String[] args) {
    String withSpace = "Remove white space from line";
    StringBuilder removeSpace = new StringBuilder();

    for (int i = 0; i<withSpace.length();i++){
        if(!Character.isWhitespace(withSpace.charAt(i))){
            removeSpace=removeSpace.append(withSpace.charAt(i));
        }
    }
    System.out.println(removeSpace);
}

Upvotes: 1

sendon1982
sendon1982

Reputation: 11234

Use apache string util class is better to avoid NullPointerException

org.apache.commons.lang3.StringUtils.replace("abc def ", " ", "")

Output 

abcdef

Upvotes: 3

v.nivuahc
v.nivuahc

Reputation: 862

If you need to remove unbreakable spaces too, you can upgrade your code like this :

st.replaceAll("[\\s|\\u00A0]+", "");

Upvotes: 53

Megawatt
Megawatt

Reputation: 163

To remove spaces in your example, this is another way to do it:

String mysz = "name=john age=13 year=2001";
String[] test = mysz.split(" ");
mysz = String.join("", mysz);

What this does is it converts it into an array with the spaces being the separators, and then it combines the items in the array together without the spaces.

It works pretty well and is easy to understand.

Upvotes: 2

Mohammad Raza
Mohammad Raza

Reputation: 45

Use mysz.replaceAll("\\s+","");

Upvotes: 4

Tony Nguyen
Tony Nguyen

Reputation: 401

import java.util.*;
public class RemoveSpace {
    public static void main(String[] args) {
        String mysz = "name=john age=13 year=2001";
        Scanner scan = new Scanner(mysz);

        String result = "";
        while(scan.hasNext()) {
            result += scan.next();
        }
        System.out.println(result);
    }
}

Upvotes: 2

Ayaskant
Ayaskant

Reputation: 559

The easiest way to do this is by using the org.apache.commons.lang3.StringUtils class of commons-lang3 library such as "commons-lang3-3.1.jar" for example.

Use the static method "StringUtils.deleteWhitespace(String str)" on your input string & it will return you a string after removing all the white spaces from it. I tried your example string "name=john age=13 year=2001" & it returned me exactly the string that you wanted - "name=johnage=13year=2001". Hope this helps.

Upvotes: 11

jayesh
jayesh

Reputation: 3625

Using Pattern And Matcher it is more Dynamic.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RemovingSpace {

    /**
     * @param args
     * Removing Space Using Matcher
     */
    public static void main(String[] args) {
        String str= "jld fdkjg jfdg ";
        String pattern="[\\s]";
        String replace="";

        Pattern p= Pattern.compile(pattern);
        Matcher m=p.matcher(str);

        str=m.replaceAll(replace);
        System.out.println(str);    
    }
}

Upvotes: 3

Gursel Koca
Gursel Koca

Reputation: 21280

st.replaceAll("\\s+","") removes all whitespaces and non-visible characters (e.g., tab, \n).

st.replaceAll("\\s+","") and st.replaceAll("\\s","") produce the same result.

The second regex is 20% faster than the first one, but as the number consecutive spaces increases, the first one performs better than the second one.

Assign the value to a variable, if not used directly:

st = st.replaceAll("\\s+","")

Upvotes: 1522

fatsoft
fatsoft

Reputation: 81

String a="string with                multi spaces ";
//or this 
String b= a.replaceAll("\\s+"," ");
String c= a.replace("    "," ").replace("   "," ").replace("  "," ").replace("   "," ").replace("  "," ");

//it work fine with any spaces *don't forget space in sting b

Upvotes: 4

Vinod Ranga
Vinod Ranga

Reputation: 531

You can do it so simply by

String newMysz = mysz.replace(" ","");

Upvotes: 9

satish
satish

Reputation: 1651

there are many ways to solve this problem. you can use split function or replace function of Strings.

for more info refer smilliar problem http://techno-terminal.blogspot.in/2015/10/how-to-remove-spaces-from-given-string.html

Upvotes: 1

jahir
jahir

Reputation: 871

One way to handle String manipulations is StringUtils from Apache commons.

String withoutWhitespace = StringUtils.deleteWhitespace(whitespaces);

You can find it here. commons-lang includes lots more and is well supported.

Upvotes: 87

groot
groot

Reputation: 323

public static void main(String[] args) {        
    String s = "name=john age=13 year=2001";
    String t = s.replaceAll(" ", "");
    System.out.println("s: " + s + ", t: " + t);
}

Output:
s: name=john age=13 year=2001, t: name=johnage=13year=2001

Upvotes: 6

user2357526
user2357526

Reputation: 71

mysz = mysz.replace(" ","");

First with space, second without space.

Then it is done.

Upvotes: 4

HANU
HANU

Reputation: 545

The code you want is

str.replaceAll("\\s","");

This will remove all the white spaces.

Upvotes: -2

Fletch
Fletch

Reputation: 5219

The most correct answer to the question is:

String mysz2 = mysz.replaceAll("\\s","");

I just adapted this code from the other answers. I'm posting it because besides being exactly what the question requested, it also demonstrates that the result is returned as a new string, the original string is not modified as some of the answers sort of imply.

(Experienced Java developers might say "of course, you can't actually modify a String", but the target audience for this question may well not know this.)

Upvotes: 123

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