How to determine whether an element is in an array in php

Method: 1. Use the in_array() function to detect whether there is a specified element value in the array, the syntax is "in_array(element value, array)"; 2. Use the array_search() function to search in the array Specify element value, syntax "array_search(element value, array)".

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

# judge one in php Is the element in the array?

Method 1: Use the in_array() function

The in_array() function can find whether the array contains an Value, returns TRUE if it exists, FALSE if it does not exist. The syntax format is as follows:

in_array($needle, $array[, $strict = FALSE])

The parameter description is as follows:

• $needle: is the value to be searched. If $needle is a string, the comparison is case-sensitive;
• $array: is the array to be searched;
• $strict: is an optional parameter, the default is FALSE.
  • If $strict is empty or FALSE, the in_array() function will only check whether the value of $needle is equal to the value in $array;
  • If the value of $strict is TRUE, in_array In addition to checking the values ​​in $needle and $array, the () function also compares their types for equality.

Tip: The in_array() function is only suitable for finding an element in a one-dimensional array, and will not recursively search for elements in each dimension of the array.

Example: Use the in_array() function to determine whether the array contains a certain value

<?php
header("Content-type:text/html;charset=utf-8");
$sites = array(&#39;a&#39;, &#39;b&#39;, &#39;1&#39;, 2, 3);
if (in_array("a", $sites))
{
    echo "指定元素在数组中";
}
else
{
    echo "指定元素不在数组中";
}
?>

2. Use the array_search() function

array_search() function searches for a key value in the array and returns the corresponding key name.

If the specified key value is found in the array, return the corresponding key name, otherwise return FALSE. If a key value is found more than once in the array, the key name matching the first found key value is returned.

The syntax format of this function is as follows:

array_search($needle, $haystack[, $strict = false])

The parameter description is as follows:

• $needle: is the value to be searched, if $needle is a character String type, the search is case-sensitive;
• $haystack: is an array;
• $strict: optional parameter, can be empty, defaults to False.
  • If $strict is False, array_search() will only compare values, not types, when searching for $needle in $haystack.
  • If $strict is True, array_search() compares both the value and type when searching for $needle in $haystack.

<?php
header("Content-type:text/html;charset=utf-8");
$sites = array("a"=>"red","b"=>"green","c"=>"blue");
if (array_search("red",$sites))
{
    echo "指定元素在数组中";
}
else
{
    echo "指定元素不在数组中";
}
echo "<br>指定元素的键名为：".array_search("red",$sites);
?>
?>

Recommended learning: "PHP Video Tutorial"

The above is the detailed content of How to determine whether an element is in an array in php. For more information, please follow other related articles on the PHP Chinese website!