How can using double quotes in PHP affect the execution of code?

Using double quotes in PHP can affect the execution of code because variables within double quotes will be evaluated and replaced with their values. This can lead to unexpected behavior if the variable names are not properly escaped or if the variables do not exist. To avoid this issue, you can use single quotes instead of double quotes when working with strings that do not require variable interpolation.

// Using single quotes to avoid variable interpolation
$name = 'John';
echo 'Hello, ' . $name . '!';