What does a \" do in php?

Question

I am very new to PHP and HTML, and I came across some code that has a \" where a select name is defined.

<select name=\"table\" ...

My question is: what is that doing?

Thank you.

Answer 1

It's an escape character. It's used to ensure that the next character is not treated as code, but as part of the string.

In this case, it means that the " is part of the string, and doesn't signify the end of the string within the code.

For example, if I want to put this inside of a string...

He said "shut up"...

I'd write something like this...

$str = "He said \"shut up\"...";

The backslash can also be used for special "sequences", which insert special characters. For example, if I want to insert a newline into the string, I'd use the \n escape sequence. Or, if I want a full CRLF, I'd use \r\n to insert both the carriage return (\r) and the line feed (\n) together. There are many escape sequences, most of which are described here, in the PHP documentation.

Answer 2

It escapes the double quote. Consider this:

echo "Hello world, John said "Hello world!"";

This would not evaluate, because John's quotewould get processed by PHP as syntax, so you use the escape character \ to skip it:

echo "Hello world, John said \"Hello world!\"";

This is only applicable to double quotes, but would also be used for single quotes in the same way:

echo 'John said \'Hello!\'';

... but this would be fine:

echo "John said 'Hello'";

Answer 3

The \ is used as an escape character in many programming langauges, such as PHP, Java, and C#. The escape character allows the usage of special characters, such as " and various special "values" such as \n for a new line.

Here is a reference to Escape sequences in PHP for further reference

Answer 4

The \ is an escape character. In your example, you are outputting HTML, and need to include the quotes, so you use the \ to ignore the quotes and thus create an HTML statement that looks like <select="table"...