# Difference between single-quoted and double-quoted

The most important difference between single and double quote, is that anything enclosed in single quotes is treated as literal text.

## Single quotes

When using single quotes we must take care of apostrophes.
To use the apostrophe in single quotes, we have to put a backslash before apostrophe (which is named as an escape character).
The backslash tells the PHP to treat the following character as part of the string.

echo 'Mike\'s first exercise'; //Result: Mike\'s first exercise

echo '"Mike\'s first exercise"'; //Result: "Mike\'s first exercise"


Therefore you do not get the value of a variable in single quotes, you will get the variable itself.

$name = "Mike"; echo '$name first exercise'; //Result: $name first exercise  ## Double quotes To get the value of a variable in a string in PHP we must use double quotes. $name = "Mike";
echo "$name first exercise"; //Result: Mike first exercise  This will lead to a decrease in performance when we use double quotes. ##### Why? When we use double quotes, PHP have to parse to check if there is any variables in there, which will inevitably lead to a drop in performance. In conclusion it’s faster to use single quotes in PHP. ## Escape sequences The most common escape sequences that are used in PHP:  \n New line \r Carriage return \t Tab \\ Backslash \$ Dollar sign

The only escape sequences that works in single quoted strings are: backslash apostrophe or backslash single quote.
All other escape sequences must be in double quotes.