Do you really know how to use the var_dump method in php?

This article is a detailed analysis and introduction to the use of the var_dump method in php. Friends who need it can refer to it

First look at the example:

The code is as follows:

<?php
$a = "alsdflasdf;a";
$b = var_dump($a);
echo "<br>";
//var_dump($c);
$d=var_dump($c);
echo "<br>";
echo $a;
echo "<br>";
echo $b;
echo "<br>";

Output:
string(12) "alsdflasdf;a"
NULL
alsdflasdf;a

What does that mean? The var_dump() method is to determine the type and length of a variable, and output the value of the variable. If the variable has a value, the value of the variable is output and the data type is returned. This Function Displays structural information about one or more expressions , including the type and value of the expression. ArrayWill recursively expand the value, showing its structure through indentation.
Its format: var_dump ( mixed expression [, mixed expression [, ...]] )
Let’s take a look at var_dump syntax:
var_dump (var,var,bar);
It should be noted that the variables in var_dump must exist. If the variable exists but the value is empty, false will be returned; if there is no variable, NULL will be returned. Himself There is an output function. No need to add other output functions.

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