Merge pull request #16772 from yabetancourt/remove-digits

BAEL-8024: How to remove numeric values from string

Author: dominiqueplante

core-java-modules/core-java-string-algorithms-4/pom.xml

@@ -12,4 +12,16 @@
         <version>0.0.1-SNAPSHOT</version>
     </parent>
 
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang.version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <commons-lang.version>3.14.0</commons-lang.version>
+    </properties>
+
 </project>

core-java-modules/core-java-string-algorithms-4/src/test/java/com/baeldung/string/removedigits/RemoveDigitsUnitTest.java

@@ -0,0 +1,64 @@
+package com.baeldung.string.removedigits;
+
+import org.apache.commons.lang3.RegExUtils;
+import org.junit.jupiter.api.Test;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class RemoveDigitsUnitTest {
+
+    static final String INPUT_STRING = "M3a9n2y n8u6m7b5e4r0s1";
+    static final String EXPECTED_STRING = "Many numbers";
+    static final String DIGIT_REGEX = "\\d";
+
+    @Test
+    void whenUsingReplaceAll_thenGetExpectedResult() {
+        String updatedString = INPUT_STRING.replaceAll(DIGIT_REGEX, "");
+
+        assertEquals(EXPECTED_STRING, updatedString);
+    }
+
+    @Test
+    void whenUsingPatternAndMatcher_thenGetExpectedResult() {
+        Pattern pattern = Pattern.compile(DIGIT_REGEX);
+        Matcher matcher = pattern.matcher(INPUT_STRING);
+        String updatedString = matcher.replaceAll("");
+
+        assertEquals(EXPECTED_STRING, updatedString);
+    }
+
+    @Test
+    void whenUsingApacheCommonsLang_thenGetExpectedResult() {
+        String updatedString = RegExUtils.replacePattern(INPUT_STRING, DIGIT_REGEX, "");
+
+        assertEquals(EXPECTED_STRING, updatedString);
+    }
+
+    @Test
+    void whenUsingForLoop_thenGetExpectedResult() {
+        StringBuilder sb = new StringBuilder();
+        for (char ch : INPUT_STRING.toCharArray()) {
+            if (!Character.isDigit(ch)) {
+                sb.append(ch);
+            }
+        }
+
+        assertEquals(EXPECTED_STRING, sb.toString());
+    }
+
+    @Test
+    void whenUsingCharacterStream_thenGetExpectedResult() {
+        String updatedString = INPUT_STRING.chars()
+          .filter(c -> !Character.isDigit(c))
+          .mapToObj(c -> (char) c)
+          .map(String::valueOf)
+          .collect(Collectors.joining());
+
+        assertEquals(EXPECTED_STRING, updatedString);
+    }
+
+}