What is the potential issue with passing variables in PHP code using single quotes vs. double quotes?

Using single quotes in PHP code will not parse variables within the string, meaning that variables will not be interpolated and will be treated as literal strings. To pass variables in PHP code using single quotes, you can concatenate the variable with the string using the dot (.) operator. Alternatively, using double quotes will parse variables within the string and interpolate their values. 

// Using double quotes to pass variables in PHP code
$name = "John";
echo "Hello, $name!";

// Using single quotes with concatenation to pass variables in PHP code
$name = "John";
echo 'Hello, ' . $name . '!';

Keywords

single quotes double quotes variable interpolation string concatenation syntax error

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