How does the usage of the dot (.) operator differ in PHP when concatenating variables versus when concatenating strings with other characters?

When using the dot (.) operator in PHP to concatenate variables, you need to ensure that there are no spaces between the dot operator and the variables. However, when concatenating strings with other characters, you can include spaces for readability. This distinction is important to remember to avoid syntax errors in your PHP code.

// Concatenating variables
$var1 = "Hello";
$var2 = "World";
echo $var1.$var2;

// Concatenating strings with other characters
$string1 = "Hello";
$string2 = "World";
echo $string1 . " " . $string2;