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PHP

Replace Newlines with BR Tag and Trim Whitespaces

How to remove leading and trailing whitespace from a string and how to replace line breaks in a string with <br> tags.

  1. nl2br() function
  2. Convert newlines (or linebreaks) \r\n with <br> tags
  3. Trimming whitespaces

nl2br() function

<?php
 //Syntax
 nl2br(string $inputString, bool $use_xhtml = true): string
  • $inputString: The input string.
  • $use_xhtml: The default setting is true. nl2br( ) inserts the XHTML compliant <br /> tag when this argument is true, set false to insert <br> tag.

The nl2br( ) function generates a string by inserting the HTML break tag  <br /> before all occurrences of the newline character in the input string. See example:

<?php
 $s = 'First line
Second line
Third line';

echo nl2br($s);
/*Prints:
First line<br />
Second line<br />
Third line
*/

echo nl2br($s, false);
/*Prints:
First line<br>
Second line<br>
Third line
*/

Replace newlines \r\n with <br> tag

The nl2br() function does not replace newlines (or linebreaks) with <br> (or <br />) tags, it just inserts a <br> tag before every newline. You can use str_replace() function if you need to replace (or remove) the newlines, see the following example:

<?php
 $lines = "line 1
line 2
line3";

$output = str_replace("\r\n", '<br>', $lines);
//line 1<br>line 2<br>line3

Note: Different operating systems use different escape sequences to represent a newline (or linebreak), for example:

  • Windows uses the \r\n escape sequence
  • Unix-based OSs use \n
  • Mac OS uses \r

To cover all operating systems, you must replace all escape sequences, see the following example:

<?php
 $lines = "line 1\rline 2\nline3\r\n";
 $nl = ["\r\n","\n","\r"];
 echo str_replace($nl, '<br>', $lines);
 //line 1<br>line 2<br>line3<br>

Trimming whitespaces

PHP provides three functions that trim leading or trailing whitespace characters from strings:

<?php
 //Syntax
 trim(string $string, string $characters = " \n\r\t\v\0"): string
 rtrim(string $string, string $characters = " \n\r\t\v\0"): string
 ltrim(string $string, string $characters = " \n\r\t\v\0"): string
  1. The trim( ) function removes both leading and trailing whitespace characters.
  2. The ltrim( ) function removes leading whitespace characters.
  3. The rtrim( ) function removes trailing whitespace characters.
    The chop ( ) function is the alias of rtrim().

The following list shows whitespace characters and how they are represented in PHP:

  • ” Space
  • \0 null
  • \t tab
  • \v vertical tab
  • \n newline
  • \r carriage return

The trim() function helps you clean up a string by removing excess whitespace from the beginning and end of the string. The following example shows the effect of this function:

<?php
 $v = "\n   trim example.  \t";
 echo trim($v);
 //Prints: "trim example."

The ltrim() and rtrim() functions work similar to trim() function, except ltrim() only trims the left side of a string and the rtrim() function trims the right side of the string. The following example shows the effect of each:

<?php
 $v = "\n   trim example.  \t";

 echo ltrim($v);
 //Prints: "trim example.  \t"
 
 echo rtrim($v); //or chop($v);
 //Prints: "\n   trim example."

If you want to remove characters other than whitespace, you can list all characters in the second optional $characters argument.

Example: Remove trailing slash from a string

<?php
 $s = 'https://brainbell.com/';
 echo rtrim($s, '/');
 //https://brainbell.com

Example: Remove spaces, commas, and dots

<?php
 $a = ' . . Hello World, , . .,  ';
 echo trim ($a, ' ,.');
 //Hello World

 echo ltrim ($a, ' ,.');
 //Hello World, , . .,  

 echo rtrim ($a, ' ,.');
 // . . Hello World

Manipulating Strings:

  1. Changing string case
  2. Comparing Strings
  3. Comparing Strings with Natural Order Algorithm
  4. Converting Strings into HTML
  5. Converting HTML Entities and Special Characters
  6. Formatting Strings
  7. Padding Strings
  8. Replacing Newlines with BR Tag and Trimming Whitespaces
  9. Converting character to code and code to character
  10. Repeat and Shuffle a String
  11. Count Characters and Words
  12. Manipulating substrings