在php中，数组被认为是布尔值吗？

Question

I have a quick question here. I know that the cakePHP find('first') function returns an array containing the first result if found, false otherwise. My question is this, what if I were to write a check like this:

if(result_is_array) // that means I have data
{
    // do something
}
else // that means result is a boolean
{
    // do something else
}

Instead of checking whether the result obtained from find('first') is an array or not, can I just say:

$result = $this->MyModel->find('first');
if($result)
{
    // do something
}

In order words, if I get an array here, will that evaluate to TRUE in php? Is if(array()) equal to true in php?

Answer 1

YES you can do

$result = $this->MyModel->find('first');
if($result)

An array with length > 0 returns true

Explanation is here in the docs

When converting to boolean, the following values are considered FALSE

• an array with zero elements

Every other value is considered TRUE

Answer 2

Instead of checking whether the result obtained from find('first') is an array or not

Yes. Do it the second way: if ($result) . If find returns an empty array or boolean false , the branch will not be executed.

The best part about doing it this way is that it makes it clear to the reader that you are checking for a non-empty value.

Answer 3

A zero value array is false

An array with values in it is true

You can view this table to see what is evaluated as true vs false .

Answer 4

根据文档 ，如果您尝试将数组视为布尔值，则数组在非空时将被视为真。

Answer 5

An empty array will always evaluate to false or if it contain any key/values then it will evaluate to true. if $this->MyModel->find('first'); always returns an array then an empty result will evaluate to false and true other wise. so your code is perfectly valid.

Answer 6

Use the following if you are looking for a TRUE value:

if ( $result !== false )
{
    // do something
}