如何在PHP中向空数组添加元素？

Question

如果我在PHP中定义一个数组,例如(我没有定义它的大小):

$cart = array();

我只是使用以下内容添加元素吗？

$cart[] = 13;
$cart[] = "foo";
$cart[] = obj;

PHP中的数组是否有添加方法,例如,cart.add(13)？

Answer 1

两者array_push和你描述的方法都有效.

$cart = array();
$cart[] = 13;
$cart[] = 14;
// etc

//Above is correct. but below one is for further understanding
$cart = array();
for($i=0;$i<=5;$i++){
    $cart[] = $i;  
}
echo "<pre>";
print_r($cart);
echo "</pre>";

是相同的:

<?php
$cart = array();
array_push($cart, 13);
array_push($cart, 14);

// Or 
$cart = array();
array_push($cart, 13, 14);
?>

Answer 2

最好不要使用array_push,只使用你的建议.这些功能只会增加开销.

//We don't need to define the array, but in many cases it's the best solution.
$cart = array();

//Automatic new integer key higher than the highest 
//existing integer key in the array, starts at 0.
$cart[] = 13;
$cart[] = 'text';

//Numeric key
$cart[4] = $object;

//Text key (assoc)
$cart['key'] = 'test';

Answer 3

根据我的经验,当密钥不重要时,解决方案很好(最好):

$cart = [];
$cart[] = 13;
$cart[] = "foo";
$cart[] = obj;

Answer 4

你可以使用array_push.它将元素添加到数组的末尾,就像在堆栈中一样.

你也可以这样做:

$cart = array(13, "foo", $obj);

Answer 5

$cart = array();
$cart[] = 11;
$cart[] = 15;

// etc

//Above is correct. but below one is for further understanding

$cart = array();
for($i = 0; $i <= 5; $i++){
          $cart[] = $i;  

//if you write $cart = [$i]; you will only take last $i value as first element in array.

}
echo "<pre>";
print_r($cart);
echo "</pre>";