PHP STR_CONTAINS ( )

To check if a String Contains a Substring in PHP

STRING: A set of characters can be called string. For example ' H ' is a character and when we use " H " in " HELLO HARRY " it becomes a string and the character " H " can be treated as an element of string .

A string is not only a single set of characters it contains multiple substrings in it. Also we can conclude that all substrings are a subset of string, but a string can b=never be a subset of a substring.

STR_CONTAINS (): - To check whether a parent string contains a substring, PHP provides us with an inbuilt function called str_contains (), which helps the developer identify the parent string contains a given substring or not.

PHP str_contains () function evaluates the substring is contained in the parent string anywhere. Then there is a substring the function will return a TRUE value else it will respond to a False value

Syntax:

Parameters:

S.NO	Parameter	Description	Optional / mandatory
1	Haystack / mains string	The original string that we intended to check within	Mandatory
2	Needle / substring	The substring that we are required to look through the main string (haystack)	mandatory

Example 1:

<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content=" width = device-width, initial-scale=1.0 " >
    <title> PHP str _ contains ( ) function </title>
</head>
<body>
<?php
$string = "this is my first PHP program for str_contains() to check for substring in the main string" . "<br>" ;
if(str_contains($string, ' string')) {
    echo "the main string contain the word ' string '";
} else {
    echo "the main string does not contain the word ' string '";
}
?>
</body>
</html>

Output:

In the above program, we have declared a variable $string with string value and used str_contains() function to find the word "s/tring" and declared the if and else statement on the bases of values returned from str_contains() function

Example 2:

<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content=" width = device-width, initial-scale=1.0 " >
    <title> PHP str _ contains ( ) function </title>
</head>
<body>
<?php
$string = "this is my first PHP program for str_contains() to check for substring in the main string" . "<br>" ;
if(str_contains($string, ' string')) {
    echo "the main string contain the word ' string '";
} else {
    echo "the main string does not contain the word ' string '";
}

if (str_contains($string, 'STRING')) {
    echo "the main string contain the word ' STRING '";
} 
else {
    echo "the main string does not contain the word ' STRING '";
}
?>
</body>
</html>

Output:

Here in this program, we have declared a variable $string with string value and used str_contains() function to find the word "string" and declared the if and else statement on the bases of values returned from the str_contains() function

DISADVANTAGES OF STR _ CONTAINS () FUNCTION

One of the major disadvantages of using this function is that it is a case sensitive function and will not look for similar words if they are uppercase or camel.
Another disadvantage of this function is that it does not return the position or index of the substring present.

ALTERNATE FUNCTION LIKE STR _ CONTAINS ()

To overcome the disadvantage of str _contains, PHP introduced a new set of functions that not only check whether the given string contains a substring. They also state exactly where the substring is located by providing us with the index of the substring.

Stripos
Strops
Strrpos

STROPS - this function is used to return the index of the searched substring

Syntax

Parameters:

S.NO	Parameter	Description	Optional / mandatory
1	string	The original string that we intended to check within	Mandatory
2	substring	The substring that we are required to look through the main string	mandatory
3	Start	To specify from where the search of substring begins	optional

For example :

<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content=" width = device-width, initial-scale=1.0 " >
    <title> PHP str _ contains ( ) function </title>
</head>
<body>
<?php
$input_string =" this is my first PHP program for strpos() to check for substring in the main string"; 
echo $string; 
$sub = "string";

if (strpos($input_string, $sub) !== false)
{
	echo "the main string contains the word ' string '". "<br>";
}
else
{
	echo "the main string does not contain the word ' string '". "<br>";
}
$sub = "STRING";
if (strpos($input_string, $sub) !== false)
{
	echo "the main string contain the word ' STRING '" . "<br>";
}
else
{
	echo "the main string does not contain the word ' STRING '". "<br>";
}
?></body>
</html>

Output:

In the above program, we have declared a variable $input_string with string value and used strpos() function to find the word "string" and declared the if and else statement on the bases of values returned from the strpos() function

STRIPS - This function is used to return the first index of the searched substring

Syntax

Parameters:

S.NO	Parameter	Description	Optional / mandatory
1	string	The original string that we intended to check within	Mandatory
2	substring	The substring that we are required to look through the main string	mandatory
3	Start	To specify from where the search of substring begins	optional

Example of STRIPS Function:

<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content=" width = device-width, initial-scale=1.0 " >
    <title> PHP str _ contains ( ) function </title>
</head>
<body>

<?php
 
$string = "hello world this is my first string";
$search = "string";
function Search($search, $string){
    $position = stripos($string, $search, 5); 
    if (is_numeric($position)){
        return "the string you are looking for is at : " . $position;
    }
    else{
        return "the string you are trying to find does not exist";
    }
}
 
echo Search($search, $string);
?>
</body>
</html>

Output:

Here in the above program, we have declared a variable $string and $search with string value and used stripos() function to find the word "string" and its position and declared the if and else statement on the bases of values returned from stripos() function

STRROPS - this function is used to return the last index of the searched substring

Syntax

Parameters:

S.NO	Parameter	Description	Optional / mandatory
1	string	The original string that we intended to check within	Mandatory
2	substring	The substring that we are required to look through the main string	mandatory
3	Start	To specify from where the search of substring begins	optional

Example of STRROPS Function:

<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content=" width = device-width, initial-scale=1.0 " >
    <title> PHP str _ contains ( ) function </title>
</head>
<body>

<?php
 
$string = "hello world this is my first string";
$search = "string";
function Search($search, $string){
    $position = strrpos($string, $search, 5); 
    if (is_numeric($position)){
        return "the string you are looking for is at : " . $position;
    }
    else{
        return "the string you are trying to find does not exist";
    }
}
 
echo Search($search, $string);
?>
</body>
</html>

Output: