split a string

mkyong · mkyong · commit 4fe61caa4de4 · 2022-02-09T16:38:19.000+08:00
diff --git a/java-string/src/main/java/com/mkyong/string/ConvertStringToInt.java b/java-string/src/main/java/com/mkyong/string/ConvertStringToInt.java
@@ -0,0 +1,26 @@
+package com.mkyong.string;
+
+public class ConvertStringToInt {
+
+    public static void main(String[] args) {
+
+        /*String number = "1";
+
+        // String to int
+        int result = Integer.parseInt(number);
+
+        // 1
+        System.out.println(result);*/
+
+        String number = "1A";
+        try {
+            int result = Integer.parseInt(number);
+            System.out.println(result);
+        } catch (NumberFormatException e) {
+            //do something for the exception.
+            System.err.println("Invalid number format : " + number);
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/ConvertStringToInt2.java b/java-string/src/main/java/com/mkyong/string/ConvertStringToInt2.java
@@ -0,0 +1,21 @@
+package com.mkyong.string;
+
+public class ConvertStringToInt2 {
+
+    public static void main(String[] args) {
+
+        // 2147483647
+        System.out.println(Integer.MAX_VALUE);
+
+        String number = "2147483648";
+        try {
+            int result = Integer.parseInt(number);
+            System.out.println(result);
+        } catch (NumberFormatException e) {
+            //do something for the exception.
+            System.err.println("Invalid number format : " + number);
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/ConvertStringToInteger.java b/java-string/src/main/java/com/mkyong/string/ConvertStringToInteger.java
@@ -0,0 +1,26 @@
+package com.mkyong.string;
+
+public class ConvertStringToInteger {
+
+    public static void main(String[] args) {
+
+        /*String number = "99";
+
+        // String to integer
+        Integer result = Integer.valueOf(number);
+
+        // 99
+        System.out.println(result);*/
+
+        String number = "D99";
+        try {
+            Integer result = Integer.valueOf(number);
+            System.out.println(result);
+        } catch (NumberFormatException e) {
+            //do something for the exception.
+            System.err.println("Invalid number format : " + number);
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/ConvertStringToIntegerJava8.java b/java-string/src/main/java/com/mkyong/string/ConvertStringToIntegerJava8.java
@@ -0,0 +1,37 @@
+package com.mkyong.string;
+
+import java.util.Optional;
+
+public class ConvertStringToIntegerJava8 {
+
+    public static void main(String[] args) {
+
+        String number = "99";
+
+        Optional<Integer> result = convertStringToInteger(number);
+
+        if (result.isPresent()) {
+            System.out.println(result.get());
+        } else {
+            System.err.println("Unable to convert the number : " + number);
+        }
+
+    }
+
+    private static Optional<Integer> convertStringToInteger(String input) {
+
+        if (input == null) return Optional.empty();
+
+        input = input.trim();
+
+        if (input.isEmpty()) return Optional.empty();
+
+        try {
+            return Optional.of(Integer.valueOf(input));
+        } catch (NumberFormatException e) {
+            return Optional.empty();
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplit.java b/java-string/src/main/java/com/mkyong/string/split/StringSplit.java
@@ -0,0 +1,20 @@
+package com.mkyong.string.split;
+
+public class StringSplit {
+
+    public static void main(String[] args) {
+
+        String phone = "012-3456789";
+        String[] output = phone.split("-");
+
+        System.out.println(output.length);  // 2
+
+        String part1 = output[0];   // 012
+        String part2 = output[1];   // 3456789
+
+        System.out.println(part1);  // 012
+        System.out.println(part2);  // 3456789
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitContains.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitContains.java
@@ -0,0 +1,21 @@
+package com.mkyong.string.split;
+
+public class StringSplitContains {
+
+    public static void main(String[] args) {
+
+        String phone = "012-3456789";
+
+        if (phone.contains("-")) {
+
+            String[] output = phone.split("-");
+            System.out.println(output[0]);  // 012
+            System.out.println(output[1]);  // 3456789
+
+        } else {
+            throw new IllegalArgumentException("String " + phone + " does not contain -");
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitJava8.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitJava8.java
@@ -0,0 +1,25 @@
+package com.mkyong.string.split;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class StringSplitJava8 {
+
+    public static void main(String[] args) {
+
+        String phone = "012-3456789";
+
+        /*List<String> output = Pattern.compile("-")
+                .splitAsStream(phone)
+                .collect(Collectors.toList());*/
+
+        List<String> output = Arrays.stream(phone.split("-"))
+                .collect(Collectors.toList());
+
+        System.out.println(output);
+
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitLimit.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitLimit.java
@@ -0,0 +1,22 @@
+package com.mkyong.string.split;
+
+public class StringSplitLimit {
+
+    public static void main(String[] args) {
+
+        String phone = "012-345-678-9";
+        String[] output = phone.split("-", 3);
+
+        System.out.println(output.length);  // 3
+
+        String part1 = output[0];   // 012
+        String part2 = output[1];   // 345
+        String part3 = output[2];   // 678-9
+
+        System.out.println(part1);
+        System.out.println(part2);
+        System.out.println(part3);
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitLookAround.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitLookAround.java
@@ -0,0 +1,27 @@
+package com.mkyong.string.split;
+
+public class StringSplitLookAround {
+
+    public static void main(String[] args) {
+
+        String phone = "012-3456789";
+
+        if (phone.contains("-")) {
+
+            // positive lookahead, split char at right-hand side
+            String[] output = phone.split("(?=-)");
+            System.out.println(output[0]);  // 012
+            System.out.println(output[1]);  // -3456789
+
+            // positive lookbehind, split char at left-hand side
+            String[] output2 = phone.split("(?<=-)");
+            System.out.println(output2[0]);  // 012-
+            System.out.println(output2[1]);  // 3456789
+
+        } else {
+            throw new IllegalArgumentException("String " + phone + " does not contain -");
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitMultiDelimiters.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitMultiDelimiters.java
@@ -0,0 +1,27 @@
+package com.mkyong.string.split;
+
+public class StringSplitMultiDelimiters {
+
+    public static void main(String[] args) {
+
+        String dir = "apple|9|1.88;2.78|0#10";
+        String[] output = dir.split("[|;#]");
+
+        System.out.println(output.length);  // 6
+
+        for (String s : output) {
+            System.out.println(s);
+        }
+
+        /*
+        System.out.println(output[0]);      // apple
+        System.out.println(output[1]);      // 9
+        System.out.println(output[2]);      // 1.88
+        System.out.println(output[3]);      // 2.78
+        System.out.println(output[4]);      // 0
+        System.out.println(output[5]);      // 10
+        */
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitNewLines.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitNewLines.java
@@ -0,0 +1,38 @@
+package com.mkyong.string.split;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class StringSplitNewLines {
+
+    public static void main(String[] args) {
+
+        StringBuilder sb = new StringBuilder();
+        sb.append("aaa \n");
+        sb.append("bbb   \r\n");
+        sb.append("ccc\n");
+        sb.append("\n");
+        sb.append("ddd\r\n");
+        sb.append("\r\n");
+        sb.append("eee\n");
+
+        String text = sb.toString();
+        System.out.println("---Original---");
+        System.out.println(text);
+
+        System.out.println("---Split---");
+
+        // split by new line, trim and filter empty line
+        List<String> lines = Arrays.stream(text.split("\\r?\\n"))
+                .map(x -> x.trim())
+                .filter(x -> x.length() > 0)
+                .collect(Collectors.toList());
+
+        for (String line : lines) {
+            System.out.println(line);
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitSpaces.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitSpaces.java
@@ -0,0 +1,16 @@
+package com.mkyong.string.split;
+
+public class StringSplitSpaces {
+
+    public static void main(String[] args) {
+
+        String str = "1 2   3 4  5";
+        String[] output = str.split("\\s+");
+
+        for (String s : output) {
+            System.out.println(s);
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitSpecialBackslash.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitSpecialBackslash.java
@@ -0,0 +1,22 @@
+package com.mkyong.string.split;
+
+import java.util.regex.Pattern;
+
+public class StringSplitSpecialBackslash {
+
+    public static void main(String[] args) {
+
+        String dir = "C:\\Users\\mkyong\\projects\\mkyong-tutorials";
+
+        // three ways to escape regex special character
+        //String[] output = dir.split("\\\\");
+        //String[] output = dir.split("[\\\\]");
+        String[] output = dir.split(Pattern.quote("\\"));
+
+        for (String s : output) {
+            System.out.println(s);
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitSpecialPeriod.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitSpecialPeriod.java
@@ -0,0 +1,22 @@
+package com.mkyong.string.split;
+
+import java.util.regex.Pattern;
+
+public class StringSplitSpecialPeriod {
+
+    public static void main(String[] args) {
+
+        String dir = "a.b.c.d.e";
+
+        // three ways to escape regex special character
+        //String[] output = dir.split("\\.");
+        //String[] output = dir.split("[.]");
+        String[] output = dir.split(Pattern.quote("."));
+
+        for (String s : output) {
+            System.out.println(s);
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitSpecialPipe.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitSpecialPipe.java
@@ -0,0 +1,24 @@
+package com.mkyong.string.split;
+
+import java.util.regex.Pattern;
+
+public class StringSplitSpecialPipe {
+
+    public static void main(String[] args) {
+
+        String csv = "a|b|c|d";
+
+        // three ways to escape regex special character
+        //  String[] output = csv.split("\\|");
+        //  String[] output = csv.split("[|]");
+        String[] output = csv.split(Pattern.quote("|"));
+
+        //System.out.println(output.length);
+
+        for (String s : output) {
+            System.out.println(s);
+        }
+
+    }
+
+}
diff --git a/java-string/src/main/java/com/mkyong/string/split/StringSplitStringTokenizer.java b/java-string/src/main/java/com/mkyong/string/split/StringSplitStringTokenizer.java
diff --git a/java-string/src/main/java/com/mkyong/string/utils/CustomStringUtils.java b/java-string/src/main/java/com/mkyong/string/utils/CustomStringUtils.java
diff --git a/java-string/src/test/java/com.mkyong.string/ConvertStringToIntTest.java b/java-string/src/test/java/com.mkyong.string/ConvertStringToIntTest.java
