php-variable (1)

Variables in PHP

Variables are used to store values, such as numbers, text strings, or arrays.

Once a variable is set, we can use it repeatedly in the script.

In PHP, you do not need to declare a variable before you set it.

All variables in PHP start with the $ symbol.

For example:

$myValue = 1;

In PHP, variable names and variable values are stored in different memory spaces, and a variable value can be represented by several different variable names.

Variable values can also be used as variable names.

For example:

<? PHP $myValue = ' abc '; $myOutput = ' myvalue '; Echo $$myOutput;? >

The results shown are:

Abc

The resulting floating-point result in PHP is not equal to the result of a floating-point variable, because the result of the operation is an approximate (imprecise)

For example:

<?PHP$a= 0.9;$b= 0.3;$c= 0.6;if(($a-$b)==$c)Echo $a,‘-‘,$b, "equals",$c;ElseIf(($a-$b)!=$c)Echo $a,‘-‘,$b, "Not equal to",$c;?>

The result is:

0.9-0.3 Not equal to 0.6