From ec3fcc078d9018d7f7ae779366741121679bf95b Mon Sep 17 00:00:00 2001
From: Kai Yuan <kent.yuan@Gmail.com>
Date: Sat, 6 Jan 2024 03:20:08 +0100
Subject: [PATCH] =?UTF-8?q?[rm-char-in-other-str]=20BAEL-7355=20Remove=20c?=
 =?UTF-8?q?haracters=20from=20a=20string=20that=E2=80=A6=20(#15531)?=
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* [rm-char-in-other-str] BAEL-7355 Remove characters from a string that are present in a second string

* [rm-char-in-other-str] shorten the package name
---
 .../RemoveCharsInAnotherStringUnitTest.java   | 75 +++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 core-java-modules/core-java-string-algorithms-4/src/test/java/com/baeldung/string/rmcharsinanotherstring/RemoveCharsInAnotherStringUnitTest.java

diff --git a/core-java-modules/core-java-string-algorithms-4/src/test/java/com/baeldung/string/rmcharsinanotherstring/RemoveCharsInAnotherStringUnitTest.java b/core-java-modules/core-java-string-algorithms-4/src/test/java/com/baeldung/string/rmcharsinanotherstring/RemoveCharsInAnotherStringUnitTest.java
new file mode 100644
index 0000000000..33bd687a4a
--- /dev/null
+++ b/core-java-modules/core-java-string-algorithms-4/src/test/java/com/baeldung/string/rmcharsinanotherstring/RemoveCharsInAnotherStringUnitTest.java
@@ -0,0 +1,75 @@
+package com.baeldung.string.rmcharsinanotherstring;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.junit.jupiter.api.Test;
+
+public class RemoveCharsInAnotherStringUnitTest {
+
+    private static final String STRING = "a b c d e f g h i j";
+    private static final String OTHER = "bdfhj";
+
+    String nestedLoopApproach(String theString, String other) {
+        StringBuilder sb = new StringBuilder();
+        for (char c : theString.toCharArray()) {
+            boolean found = false;
+            for (char o : other.toCharArray()) {
+                if (c == o) {
+                    found = true;
+                    break;
+                }
+            }
+            if (!found) {
+                sb.append(c);
+            }
+        }
+        return sb.toString();
+    }
+
+    String loopAndIndexOfApproach(String theString, String other) {
+        StringBuilder sb = new StringBuilder();
+        for (char c : theString.toCharArray()) {
+            if (other.indexOf(c) == -1) {
+                sb.append(c);
+            }
+        }
+        return sb.toString();
+    }
+
+    String hashSetApproach(String theString, String other) {
+        StringBuilder sb = new StringBuilder();
+        Set<Character> set = new HashSet<>(other.length());
+        for (char c : other.toCharArray()) {
+            set.add(c);
+        }
+
+        for (char i : theString.toCharArray()) {
+            if (!set.contains(i)) {
+                sb.append(i);
+            }
+        }
+        return sb.toString();
+    }
+
+    @Test
+    void whenUsingTheNestedLoopApproach_thenGetExpectedResult() {
+        String result = nestedLoopApproach(STRING, OTHER);
+        assertEquals("a  c  e  g  i ", result);
+    }
+
+    @Test
+    void whenUsingTheLoopAndIndexOfApproach_thenGetExpectedResult() {
+        String result = loopAndIndexOfApproach(STRING, OTHER);
+        assertEquals("a  c  e  g  i ", result);
+    }
+
+    @Test
+    void whenUsingTheHashSetApproach_thenGetExpectedResult() {
+        String result = hashSetApproach(STRING, OTHER);
+        assertEquals("a  c  e  g  i ", result);
+    }
+
+}
\ No newline at end of file