Working With PHP Strings
In programming, a string is a sequence of letters, symbols, characters and arithmetic values or combination of all tied together in single or double quotes. For example, "I Love PHP", "10", '100.01', "", etc are all examples of strings.
Declaring String Variable in PHP
$my_name = "John";
In PHP, a variable must start with $ sign followed by variable name. The string value must be wrapped in double or single quotes.
Concatenate / Join Strings in PHP
Sometimes while working with strings in our code, we need to join two strings. In PHP, you can use '.' to concatenate two or more strings together to form a single string.
$my_first_name = "John";
$my_last_name = "Doe";
//concatenate my first and last name
$my_full_name = $my_first_name. " " . $my_last_name;
The above example with output "John Doe".
Single and Double Quotes PHP Strings
Strings in PHP can be wrapped in double or singles quotes. Using double quotes is the primary method. Double quotes allow us to escape specials characters in our string. For example, when you use the $ sign within double quotes it is treated as php variable and will not show up in the output
$str = "hello";
echo "$str everyone!";
Notice in the above code, we wrapped the $str variable in double quoted string. The above example will output "hello everyone" NOT "$str everyone"
Single quotes can be used to do things like...
$quote_of_the_day = '"To be or not to be. That is the question"';
Notice, we used double quotes around the text. The code will output "To be or not to be. That is the question".
Single Quotes vs. Double Quotes in PHP Strings
It is good practice when working PHP code to wrap stings in double quotes. Single quotes should be used when writing HTML code within PHP code since attribute values of HTML tags should be wrapped in double quotes as good coding practice.