100 PHP Functions You Should Know – Part 2

In this tutorial we will discover the list of the 100 most used native functions in PHP.

51. fclose

Close an open file. This function returns TRUE on success or FALSE on failure.


<?php
   $file = fopen("file.txt","r");
   //...
   fclose($file);
?>

<?php

$file = fopen("file.txt","r");

//...

fclose($file);

52. is_int

Is used to test whether the type of the specified variable is an integer or not.


<?php
   $nbr = 123;

   if (is_int($nbr))
   {
      echo "$nbr is an integer" ;
   }
   else
   {
      echo "$nbr is not a whole number " ;
   }
?>

<?php

$nbr = 123;

if (is_int($nbr))

{

echo "$nbr is an integer" ;

}

else

{

echo "$nbr is not a whole number " ;

}

53. is_file

Checks whether the specified file is a regular file. This function returns TRUE if it is a file.


<?php
   $file = "file.txt";

   if(is_file($file))
   {
      echo ("$file is a regular file");
   }
   else
   {
      echo ("$file is not a regular file");
   }
?>

<?php

$file = "file.txt";

if(is_file($file))

{

echo ("$file is a regular file");

}

else

{

echo ("$file is not a regular file");

}

54. array_slice

Returns the selected parts of an array.


<?php
     $colors = array("orange","black","white","yellow","green");
     print_r(array_slice($colors, 2));
?>

<?php

$colors = array("orange","black","white","yellow","green");

print_r(array_slice($colors, 2));

55. preg_match_all

Match all occurrences of the pattern in the string.


<?php
    preg_match_all("/\(?  (\d{3})?  \)?  (?(1)  [\-\s] ) \d{3}-\d{4}/x",
                "Call 222-1414 or 1-900-888-1414", $phones);
    print_r($phones);
?>

<?php

preg_match_all("/$? (\d{3})? $? (?(1) [\-\s] ) \d{3}-\d{4}/x",

"Call 222-1414 or 1-900-888-1414", $phones);

print_r($phones);

Output:


Array
(
    [0] => Array
        (
            [0] => 222-1414
            [1] => 900-888-1414
        )

    [1] => Array
        (
            [0] => 
            [1] => 900
        )

)

Array

(

[0] => Array

(

[0] => 222-1414

[1] => 900-888-1414

)

[1] => Array

(

[0] =>

[1] => 900

)

56. ucfirst

Converts the first character of a string to uppercase.


<?php
       echo ucfirst("hello world!");
?>

<?php

echo ucfirst("hello world!");

57. intval

Is used to retrieve the entire part of a value.


<?php
       echo intval(255.22);
?>

<?php

echo intval(255.22);

58. str_repeat

Repeats a string according to the number provided in parameter.


<?php
       echo str_repeat(".",12);
?>

<?php

echo str_repeat(".",12);

59. serialize

Converts a storable representation of a value.


<?php
    $serializedData = serialize(array('Blue', 'Red', 'Green'));
    echo  $serializedData;
?>

<?php

$serializedData = serialize(array('Blue', 'Red', 'Green'));

echo $serializedData;

60. array_filter

filters the values of an array using a callback function.


<?php
    function checkOdd($nbr)
    {
       return($nbr & 1);
    }

    $tab = array("x","y",1,2,3);
    print_r(array_filter($tab, "checkOdd"));
?>

<?php

function checkOdd($nbr)

{

return($nbr & 1);

}

$tab = array("x","y",1,2,3);

print_r(array_filter($tab, "checkOdd"));

61. mkdir

Create a new directory.


<?php
     mkdir("Document");
?>

<?php

mkdir("Document");

62. is_callable

Is used to test only the contents of a variable, whether it can be called as a function or not.


<?php
   function f(){
   }
   echo is_callable('f');
?>

<?php

function f(){

}

echo is_callable('f');

63. ltrim

Removes spaces or other predefined characters to the left of a string.


<?php
     $var = "Hello Code4Example!";
     echo ltrim($var,"Hello");
?>

<?php

$var = "Hello Code4Example!";

echo ltrim($var,"Hello");

64. ob_start

PHP being an interpreted language, each statement is executed one after the other. PHP therefore tends to send HTML code to browsers in chunks, which reduces performance. Using buffering, the generated HTML code is stored in a buffer or variable of type string and is sent to the buffer for rendering after the execution of the last statement of the PHP script.

But buffering is not enabled by default. To activate it, you must first use the ob_start() function in the script.


<?php
     function callback($buffer){ 
         .....
     } 
  
     ob_start("callback"); 
     echo "Hello Code4Example!"; 
     ob_end_flush(); 
?>

<?php

function callback($buffer){

.....

}

ob_start("callback");

echo "Hello Code4Example!";

ob_end_flush();

65. round

Round off a floating point number


<?php
     echo(round(3.9754341,2));
?>

<?php

echo(round(3.9754341,2));

66. fwrite

Writes to an open file. This function returns the number of bytes written.


<?php
     $file = fopen("file.txt","w");
     echo fwrite($file,"Hello World!");
     fclose($file);
?>

<?php

$file = fopen("file.txt","w");

echo fwrite($file,"Hello World!");

fclose($file);

67. array_unique

Removes duplicates from a table. If two or more values are the same, the first will be kept and the other will be deleted.


<?php
     $colors = array("1"=>"blue", "2"=>"orange", "3"=>"blue");
     print_r(array_unique($colors));
?>

<?php

$colors = array("1"=>"blue", "2"=>"orange", "3"=>"blue");

print_r(array_unique($colors));

68. array_search

Finds a value in an array and returns the key.


<?php
     $colors = array("1"=>"blue", "2"=>"orange", "3"=>"red");
     print_r(array_search("blue", $colors));
?>

<?php

$colors = array("1"=>"blue", "2"=>"orange", "3"=>"red");

print_r(array_search("blue", $colors));

69. reset

Moves the internal pointer to the first element of the array.


<?php
    $colors = array("Red", "Blue", "Green", "Orange");

    echo current($colors);  //Red
    echo next($colors);    //Blue
    echo reset($colors);   //Red
?>

<?php

$colors = array("Red", "Blue", "Green", "Orange");

echo current($colors); //Red

echo next($colors); //Blue

echo reset($colors); //Red

70. array_unshift

Inserts new elements into an array. The new values will be inserted at the beginning of the table.


<?php
      $colors = array("1"=>"Red", "2"=>"Blue");
      array_unshift($colors, "Orange");
      print_r($colors);
?>

<?php

$colors = array("1"=>"Red", "2"=>"Blue");

array_unshift($colors, "Orange");

print_r($colors);

71. parse_url

Processes a URL and reviews its components


<?php
    $url = 'https://username:password@host:1080/path?arg=age#12';

    var_dump(parse_url($url));
    var_dump(parse_url($url, PHP_URL_SCHEME));
    var_dump(parse_url($url, PHP_URL_USER));
    var_dump(parse_url($url, PHP_URL_PASS));
    var_dump(parse_url($url, PHP_URL_HOST));
    var_dump(parse_url($url, PHP_URL_PORT));
   var_dump(parse_url($url, PHP_URL_PATH));
   var_dump(parse_url($url, PHP_URL_QUERY));
   var_dump(parse_url($url, PHP_URL_FRAGMENT));
?>

<?php

$url = 'https://username:password@host:1080/path?arg=age#12';

var_dump(parse_url($url));

var_dump(parse_url($url, PHP_URL_SCHEME));

var_dump(parse_url($url, PHP_URL_USER));

var_dump(parse_url($url, PHP_URL_PASS));

var_dump(parse_url($url, PHP_URL_HOST));

var_dump(parse_url($url, PHP_URL_PORT));

var_dump(parse_url($url, PHP_URL_PATH));

var_dump(parse_url($url, PHP_URL_QUERY));

var_dump(parse_url($url, PHP_URL_FRAGMENT));

Output:


array(8) {
  ["scheme"]=>
  string(5) "https"
  ["host"]=>
  string(4) "host"
  ["port"]=>
  int(1080)
  ["user"]=>
  string(8) "username"
  ["pass"]=>
  string(8) "password"
  ["path"]=>
  string(5) "/path"
  ["query"]=>
  string(7) "arg=age"
  ["fragment"]=>
  string(2) "12"
}
string(5) "https"
string(8) "username"
string(8) "password"
string(4) "host"
int(1080)
string(5) "/path"
string(7) "arg=age"
string(2) "12"

array(8) {

["scheme"]=>

string(5) "https"

["host"]=>

string(4) "host"

["port"]=>

int(1080)

["user"]=>

string(8) "username"

["pass"]=>

string(8) "password"

["path"]=>

string(5) "/path"

["query"]=>

string(7) "arg=age"

["fragment"]=>

string(2) "12"

}

string(5) "https"

string(8) "username"

string(8) "password"

string(4) "host"

int(1080)

string(5) "/path"

string(7) "arg=age"

string(2) "12"

72. func_get_args

Returns the arguments of a function in the form of an array.


<?php
  function f()
  {
    $n = func_num_args();
    echo "Number of arguments : $n";
    if ($n >= 2) {
        echo "The third argument is : " . func_get_arg(2);
    }
  }

  f(1, 2, 3, 4);
?>

<?php

function f()

{

$n = func_num_args();

echo "Number of arguments : $n";

if ($n >= 2) {

echo "The third argument is : " . func_get_arg(2);

}

f(1, 2, 3, 4);

73. end

Moves the internal pointer to the end of the array.


<?php
   $colors = array("Red", "Blue", "Green", "Brown");

   echo current($colors);
   echo end($colors); 
?>

<?php

$colors = array("Red", "Blue", "Green", "Brown");

echo current($colors);

echo end($colors);

74. base64_encode

Encodes the data supplied with base64. This encoding is designed to ensure that binary data survives transport through unclean transport layers.


<?php
   $str = 'This is an encoded string';
   echo base64_encode($str);
?>

<?php

$str = 'This is an encoded string';

echo base64_encode($str);

75. unserialize

Converts serialized data to real data.


<?php
   $serializedData = serialize(array('Java', 'PHP', 'Python'));
   echo  $serializedData;

   // deserialize data
   $tab = unserialize($serializedData);
   // Display unserialized data;
   var_dump ($tab);
?>

<?php

$serializedData = serialize(array('Java', 'PHP', 'Python'));

echo $serializedData;

// deserialize data

$tab = unserialize($serializedData);

// Display unserialized data;

var_dump ($tab);

76. max

Return the largest value in an array.


<?php
   echo(max(3,4,6,7,20));
?>

<?php

echo(max(3,4,6,7,20));

77. preg_split

Converts a string to an array according to the regular expression supplied as a parameter.


<?php
   $ip = "193.354.123.000"; // address IP
   $iptab = preg_split("/\./", $ip);  
   
   print "$iptab[0]";    //193
   print "$iptab[1]";   //354
   print "$iptab[2]";   //123
   print "$iptab[3]";   //000
?>

<?php

$ip = "193.354.123.000"; // address IP

$iptab = preg_split("/\./", $ip);

print "$iptab[0]"; //193

print "$iptab[1]"; //354

print "$iptab[2]"; //123

print "$iptab[3]"; //000

78. gettype

Is used to retrieve the type of a variable.


<?php
    echo gettype(55);
    echo gettype(false);
    echo gettype(array());
?>

<?php

echo gettype(55);

echo gettype(false);

echo gettype(array());

79. strrpos

Finds the position of the last occurrence of a string within another string.


<?php
    echo strrpos("I love tomatos, I love tomatos too!","tomatos");
?>

<?php

echo strrpos("I love tomatos, I love tomatos too!","tomatos");

80. version_compare

Compare the two standardized versions of PHP.


<?php
    if (version_compare(PHP_VERSION, '5.0.0', '>=')) {
        echo "My version is : " . PHP_VERSION . "n";
    }
?>

<?php

if (version_compare(PHP_VERSION, '5.0.0', '>=')) {

echo "My version is : " . PHP_VERSION . "n";

}

81. array_push

Inserts one or more elements at the end of an array.


<?php
    $colors = array("1"=>"orange","2"=>"brown");
    array_push($colors,"red","green");
    print_r($colors);
?>

<?php

$colors = array("1"=>"orange","2"=>"brown");

array_push($colors,"red","green");

print_r($colors);

82. floor

Rounds a number to the nearest whole number, if necessary.


<?php
    echo(floor(0.90));
?>

<?php

echo(floor(0.90));

83. strtotime

Converts a textual date-time to English in a Unix timestamp.


<?php
    echo(strtotime("2 May 2006"));
?>

<?php

echo(strtotime("2 May 2006"));

84. htmlspecialchars

Converts some predefined characters to HTML entities.


<?php
    $str = "Welcom <b>to</b> Code4Example.com";
    echo htmlspecialchars($str);
?>

<?php

$str = "Welcom <b>to</b> Code4Example.com";

echo htmlspecialchars($str);

85. ini_get

The configuration settings are in the php.ini file. The defined value of each parameter can be identified using the ini_get function.


<?php
  echo ini_get('upload_max_filesize'); //la sortie est par défaut 2M
?>

<?php

echo ini_get('upload_max_filesize'); //la sortie est par défaut 2M

86. ini_set

The configuration settings are in the php.ini file. The defined value of each parameter can be modified using the ini_set function.


<?php
   ini_set('upload_max_filesize', '3M');
?>

<?php

ini_set('upload_max_filesize', '3M');

87. extension_loaded

This function returns TRUE if the extension identified by its name is loaded, otherwise returns FALSE.


<?php
  $str = chr(046);
  echo("We'll be there, you $str me!");
?>

<?php

$str = chr(046);

echo("We'll be there, you $str me!");

88. is_bool

This function is used to determine whether a variable is a Boolean or not.


<?php
  $var = true;
  if (is_bool($var))
      echo "This is a boolean";
  else
      echo "This is not a boolean";
?>

<?php

$var = true;

if (is_bool($var))

echo "This is a boolean";

else

echo "This is not a boolean";

89. ksort

Sorts an associative array in ascending order, by key.


<?php
  $age=array("55"=>"Alex","37"=>"Ali","13"=>"Emily");
  ksort($age);
  print_r($age);
?>

<?php

$age=array("55"=>"Alex","37"=>"Ali","13"=>"Emily");

ksort($age);

print_r($age);

90. Extension_loaded

This function returns TRUE if the extension identified by its name is loaded, otherwise returns FALSE.


<?php
  if (extension_loaded('gd'))
    echo "GD installed";
  else
    echo "GD not installed";
?>

<?php

if (extension_loaded('gd'))

echo "GD installed";

else

echo "GD not installed";

91. array_reverse

Returns an array in reverse order.


<?php
    $languages = array("1"=>"C++","2"=>"Java","3"=>"PHP");
    print_r(array_reverse($languages));
?>

<?php

$languages = array("1"=>"C++","2"=>"Java","3"=>"PHP");

print_r(array_reverse($languages));

92. ord

Returns the ASCII value of the first character of a string.


<?php
  echo ord("hello");   //The ASCII value of 'h' is 104
?>

<?php

echo ord("hello"); //The ASCII value of 'h' is 104

93. uniqid

Generate a unique identifier.


<?php
    echo uniqid();
?>

<?php

echo uniqid();

94. strtr

Replaces a substring in a string with a character string.


<?php
    echo strtr("Code3Example","H3","W4");
?>

<?php

echo strtr("Code3Example","H3","W4");

95. array_diff

Compares the values of two (or more) arrays and returns the differences.


<?php
    $languages1 = array("1"=>"PHP","2"=>"Java","3"=>"C","4"=>"C++");
    $languages2 = array("5"=>"Java","6"=>"C","7"=>"C++");

    $res = array_diff($languages1, $languages2);
    print_r($res);
?>

<?php

$languages1 = array("1"=>"PHP","2"=>"Java","3"=>"C","4"=>"C++");

$languages2 = array("5"=>"Java","6"=>"C","7"=>"C++");

$res = array_diff($languages1, $languages2);

print_r($res);

96. error_reporting

Specifies which errors are reported.


<?php
   //Turn off error reporting
   error_reporting(0);

   //Report all errors
   error_reporting(E_ALL);
?>

<?php

//Turn off error reporting

error_reporting(0);

//Report all errors

error_reporting(E_ALL);

97. ceil

Rounds a number to the nearest whole number, if necessary.


<?php
    echo(ceil(0.60));
?>

<?php

echo(ceil(0.60));

98. urlencode

This function is useful when encoding a string for use in a request part of a URL, as it is a convenient way to pass variables to the next page.


<?php
    echo '<a href="cgi?foo='. urlencode($foo).'">';
?>

<?php

echo '<a href="cgi?foo='. urlencode($foo).'">';

99. min

Returns the smallest value in an array.


<?php
    echo(min(1,2,3,0,20));
?>

<?php

echo(min(1,2,3,0,20));

100. print_r

Is used to display the contents of a variable in a readable way.


<?php
$lang = array("PHP"=>"1", "Java"=>"2", "Python"=>"3");
print_r($lang);
?>

<?php

$lang = array("PHP"=>"1", "Java"=>"2", "Python"=>"3");

print_r($lang);

The 100 PHP Functions You Should Know – Part 1

51. fclose

52. is_int

53. is_file

54. array_slice

55. preg_match_all

56. ucfirst

57. intval

58. str_repeat

59. serialize

60. array_filter

61. mkdir

62. is_callable

63. ltrim

64. ob_start

65. round

66. fwrite

67. array_unique

68. array_search

69. reset

70. array_unshift

71. parse_url

72. func_get_args

73. end

74. base64_encode

75. unserialize

76. max

77. preg_split

78. gettype

79. strrpos

80. version_compare

81. array_push

82. floor

83. strtotime

84. htmlspecialchars

85. ini_get

86. ini_set

87. extension_loaded

88. is_bool

89. ksort

90. Extension_loaded

91. array_reverse

92. ord

93. uniqid

94. strtr

95. array_diff

96. error_reporting

97. ceil

98. urlencode

99. min

100. print_r

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