What are the differences between using single and double quotes in PHP when concatenating strings and variables?

When concatenating strings and variables in PHP, using single quotes will treat everything inside the quotes as a literal string, while using double quotes allows for variable interpolation, meaning variables will be evaluated and their values inserted into the string. To concatenate strings and variables using double quotes, simply include the variables directly within the quotes. If using single quotes, concatenate the variables using the period (.) operator outside of the quotes. 

// Example using double quotes
$name = "Alice";
echo "Hello, $name!";

// Example using single quotes
$name = "Bob";
echo 'Hello, ' . $name . '!';

Keywords

PHP single quotes double quotes concatenation strings variables

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