How do I check if a string contains a list of characters?

Question

How do I check if a list of characters are in a String, for example "ABCDEFGH" how do I check if any one of those is in a string.

Solution 1

use regular expression in java to check using str.matches(regex_here) regex in java

for example:

    if("asdhAkldffl".matches(".*[ABCDEFGH].*"))
    {
        System.out.println("yes");
    }

Solution 2

The cleanest way to implement this is using StringUtils.containsAny(String, String)

package com.sandbox;

import org.apache.commons.lang.StringUtils;
import org.junit.Test;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

public class SandboxTest {

    @Test
    public void testQuestionInput() {
        assertTrue(StringUtils.containsAny("39823839A983923", "ABCDEFGH"));
        assertTrue(StringUtils.containsAny("A", "ABCDEFGH"));
        assertTrue(StringUtils.containsAny("ABCDEFGH", "ABCDEFGH"));
        assertTrue(StringUtils.containsAny("AB", "ABCDEFGH"));
        assertFalse(StringUtils.containsAny("39823839983923", "ABCDEFGH"));
        assertFalse(StringUtils.containsAny("", "ABCDEFGH"));
    }

}

Maven dependency:

    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
        <version>3.5</version>
    </dependency>

Solution 3

From Guava: CharMatcher.matchesAnyOf

private static final CharMatcher CHARACTERS = CharMatcher.anyOf("ABCDEFGH");
assertTrue(CHARACTERS.matchesAnyOf("39823839A983923"));

Solution 4

If "ABCDEFGH" is in a string variable, the regular expression solution is not good. It will not work if the string contains any character that has a special meaning in regular expressions. Instead I suggest:

    Set<Character> charsToTestFor = "ABCDEFGH".chars()
            .mapToObj(ch -> Character.valueOf((char) ch))
            .collect(Collectors.toSet());
    String stringToTest = "asdhAkldffl";
    boolean anyCharInString = stringToTest.chars()
            .anyMatch(ch -> charsToTestFor.contains(Character.valueOf((char) ch)));
    System.out.println("Does " + stringToTest + " contain any of " + charsToTestFor + "? " + anyCharInString);

With the strings asdhAkldffl and ABCDEFGH this snippet outputs:

Does asdhAkldffl contain any of [A, B, C, D, E, F, G, H]? true

Solution 5

This is how it can be achieved using Pattern and Matcher,

Pattern p = Pattern.compile("[^A-Za-z0-9 ]");
Matcher m = p.matcher(trString);
boolean hasSpecialChars = m.find();

View more solutions

Comments

[Alex Kreutznaer]

Do you mean you want to check if some String contains characters from the list?

[sage88]

Should probably look around a bit elsewhere before asking questions like this.

[Mawia]

I think OP means to ask regular expression but did not know how to ask

[Pradeep Simha]

This is a inefficient solution, using regex is better.

[EAKAE]

I postedit because it is simpler and easier to understand if you don't know regex yet.

[mre]

what about locale sensitivity?

[Rana Ghosh]

@advocate Probably because it's not build into java. You have to download Apache Commons Lang to get it. commons.apache.org/proper/commons-lang Make sure to add it to your classpath.

[fIwJlxSzApHEZIl]

Thanks! For anyone else you need to unzip the download package (I recommend in your project folder). Right click your project in Eclipse -> Build Path -> Configure Build Path -> Add External Jars -> Select the commons lang jars. You will also need the right version number in your inport statement: import org.apache.commons.lang3.StringUtils;

[Alex]

Yeah but good luck if you want to check if it contains only numeric data with this method.

[Evren Ozturk]

Even if it is. That is not an acceptable attitude to answer.

[Vitali Tchalov]

This should be the accepted answer - it is cleaner, simpler and in my tests for verifying Windows file names for reserved characters using a pre-compiled RegEx (e.g. Pattern.compile(".*?[<>:\"/\\|?*]+?.*")), StringUtils.containsAny performed ~6 times faster.

[JGFMK]

The question asked for a list of characters, not a single one

[Rana Ghosh]

I hadn't considered this when I gave my answer. This is a good point. There are ways to get around it. You could escape special characters with a "\". I'm not saying this as an "on the other hand," I'm just letting others know every angle.