PHP Array Functions
Array functions are built-in tools that work on whole arrays. Some of them change the array, and some only read from it.
Counting before and after a growth
The list starts with two items and its count prints. One more item is appended, and the count prints again.
<?php
$list = ["milk", "bread"];
echo count($list) . "\n";
$list[] = "eggs";
echo count($list) . "\n";Appending with empty brackets
Empty brackets add a value at the end of the array. print_r shows eggs in the last place.
<?php
$list = ["milk", "bread"];
$list[] = "eggs";
print_r($list);Adding two values with array_push
array_push adds both new values at the end. The count it hands back prints first, and print_r shows the grown list.
<?php
$list = ["milk", "bread"];
$count = array_push($list, "eggs", "rice");
echo $count . "\n";
print_r($list);Testing for a value with in_array
in_array answers true when the value sits in the array. var_dump shows true for milk and false for cheese.
<?php
$list = ["milk", "bread", "eggs"];
var_dump(in_array("milk", $list));
var_dump(in_array("cheese", $list));Joining two arrays with array_merge
array_merge places the values of the second array after the first ones. print_r shows one joined array.
<?php
$first = ["milk", "bread"];
$second = ["eggs", "rice"];
$all = array_merge($first, $second);
print_r($all);Example
<?php
$guests = ["Ana", "Bo"];
$guests[] = "Cy";
array_push($guests, "Dee", "Eli");
print_r($guests);
echo count($guests) . " guests\n";Key points
- Built-in array functions do common jobs on whole arrays at once.
- An empty pair of brackets after a name appends a value to that array.
- array_push adds one or more values at the end of an array.
- array_push hands back the new count of the array.
- in_array tests whether a value sits in an array.
- array_merge joins two arrays into one new array.
In this example, the guest list starts with two names. Empty brackets add Cy, and array_push adds Dee and Eli. print_r shows all five names in order, and the last line prints the final count.
Try it Yourself
Edit the code, then press Run.
Running is simulated · Programiz PHP Compiler
Exercise
What does var_dump(in_array("rice", $list)) print when rice is not in $list?