Problems and solutions of using In_array functions in PHP _php tips

First, introduce the requirements background:

Invoice method:

0= donation (Don't ask me why, historical reasons)

1= sent to China

2= Request

3= Electronic Invoice

Now you want to test the data submitted by the User:

Php;auto-links:false; " >if (!in_array ($_post[' invoice_action ', Array (0,1,2,3))) { 
  throw new Exception (' Please select the correct invoice method '); 

This time there is a problem, if there is no $_POST[‘invoice_action'] such value, why not throw an exception?

It is confirmed that this is PHP as a weak type language of a pit, yes, it is a pit.

Take a look at this set of code:

Echo In_array (', array (0))? 1:0;   Results: 1
echo in_array (null, array (0))? 1:0;  Results: 1
Echo In_array (false, array (0))? 1:0;//Result: 1

How are we going to get around or fill out this big hole?

Method One: In_array supports the third parameter, forcing data type detection

Echo In_array (", array (0), true)?" 1:0;   Result: 0
echo in_array (null, array (0), true)? 1:0;  Result: 0
Echo In_array (false, array (0), true)? 1:0;//Result: 0

Method Two: Still is the data type direction, changes the array 0 to the string

Echo In_array (', Array (' 0 '), true)? 1:0;   Result: 0
echo in_array (null, Array (' 0 '), true)? 1:0;  Result: 0
Echo In_array (False, Array (' 0 '), true)? 1:0;//Result: 0

Summarize

The above is about PHP in the use of In_array functions encountered problems and solutions, I hope this article on the same problem with friends can help, if you have questions can be exchanged message.