How to access array elements in php

PHP method of accessing array elements

in_array() function

in_array() function Searches an array for a specific value and returns true if the value is found, false otherwise. Its form is as follows:

boolean in_array(mixed needle,array haystack[,boolean strict]);

Look at the following example to find whether the variable apple is already in the array. If it is, output a piece of information:

$fruit = "apple";  
$fruits = array("apple","banana","orange","pear");  
if( in_array($fruit,$fruits) )  
    echo "$fruit 已经在数组中";

The third parameter is optional, it is mandatory in_array() considers types when searching.

array_key_exists() function

If a specified key is found in an array, the function array_key_exists() returns true, otherwise it returns false. Its form is as follows:

boolean array_key_exists(mixed key,array array);

The following example will search for apple in the array key. If found, the color of the fruit will be output:

$fruit["apple"] = "red";  
$fruit["banana"] = "yellow";  
$fruit["pear"] = "green";  
if(array_key_exists("apple", $fruit)){  
    printf("apple's color is %s",$fruit["apple"]);  
}

The result obtained by executing this code:

apple's color is red

array_search() function

array_search() function searches for a specified value in an array, if found, returns the corresponding key, otherwise returns false. Its form is as follows:

mixed array_search(mixed needle,array haystack[,boolean strict])

The following example searches $fruits for a specific date (December 7), and if found, returns relevant information about the corresponding state:

$fruits["apple"] = "red";  
$fruits["banana"] = "yellow";  
$fruits["watermelon"]="green";  
$founded = array_search("green", $fruits);  
if($founded)  
    printf("%s was founded on %s.",$founded, $fruits[$founded])

Program The running results are as follows:

watermelon was founded on green.

array_keys() function

array_keys() function returns an array containing all keys found in the searched array. It has the following form:

array array_keys(array array[,mixed search_value])

If the optional parameter search_value is included, only keys matching that value will be returned. The following example will output all arrays found in the $fruit array:

$fruits["apple"] = "red";  
$fruits["banana"] = "yellow";  
$fruits["watermelon"]="green";  
$keys = array_keys($fruits);  
print_r($keys);

The program running results are as follows:

Array ( [0] => apple [1] => banana [2] => watermelon )

array_values() function

The array_values() function returns all the values ​​in an array and automatically provides a numerical index for the returned array. Its form is as follows:

array array_values(array array)

The following example will obtain the value of each element found in $fruits:

$fruits["apple"] = "red";  
$fruits["banana"] = "yellow";  
$fruits["watermelon"]="green";  
$values = array_values($fruits);  
print_r($values);

The program running result is as follows:

Array ( [0] => red [1] => yellow [2] => green )

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