Php: substr: Return part of a string

Signature

substr ( string $string , int $offset , int|null $length = null ) : string

 

Description

Returns the portion of string specified by the offset and length parameters.

 

If offset is non-negative, the returned string will start at the offset'th position in string, counting from zero.

If offset is negative, the returned string will start at the offset'th character from the end of string.

If string is less than offset characters long, false will be returned.

 

Example

$substr1 = substr($str1, 1, 2);

$substr2 = substr($str1, -3, 3);

 

substr_demo.php

#!/usr/bin/php

<?php

   $str1 = 'Hello';
   $substr1 = substr($str1, 1, 2);
   $substr2 = substr($str1, -3, 3);
   
    echo "\$str1: $str1\n";
    echo "\$substr1: $substr1\n";
    echo "\$substr2: $substr2\n";
?>

 

Output

$./substr_demo.php 

$str1: Hello
$substr1: el
$substr2: llo

 

 

 

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Java: Remove first character of a string

Using ‘subString’ method, you can extract the string except the first character.

Example

public static String removeFirstChar(String str) {

         if (str == null || str.isEmpty()) {

                  throw new IllegalArgumentException("Input must not be null or empty");

         }

        

         return str.substring(1);

}

StringUtil.java

package com.smaple.app.utils;

public class StringUtil {

 public static String removeFirstChar(String str) {
  if (str == null || str.isEmpty()) {
   throw new IllegalArgumentException("Input must not be null or empty");
  }

  return str.substring(1);

 }
}

StringUtilTest.java

package com.sample.app.utils;

import static com.smaple.app.utils.StringUtil.removeFirstChar;
import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class StringUtilTest {

 @Test(expected = IllegalArgumentException.class)
 public void inputIsNull() {
  String text = null;

  removeFirstChar(text);
 }

 @Test(expected = IllegalArgumentException.class)
 public void inputIsEmpty() {
  String text = "";

  removeFirstChar(text);
 }

 @Test
 public void inputLengthIs1() {
  String text = "a";
  String expected = "";
  
  String result = removeFirstChar(text);
  assertEquals(expected, result);
 }

 @Test
 public void inputLengthIsGreaterThan1() {
  String text = "hello";
  String expected = "ello";

  String result = removeFirstChar(text);

  assertEquals(expected, result);

 }
}

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