PHP103

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PHP Start Symbols

 <?
 <?php
 

• both of these groups of symbols indicate the start of a section of PHP code - either can be used, although PSR-1 coding standards specifies that <?php should be used.

PHP End Symbols

 ?>
 

• these symbols indicate the end of a section of PHP code

Commenting in PHP

 <?
    echo 'This would be printed out';

    // THIS IS A SINGLE LINE COMMENT AND WON'T BE PRINTED
    # BELIEVE IT OR NOT, THIS IS ALSO A SINGLE LINE COMMENT
    /* THIS SYMBOL PAIR
       STARTS A MULTI-LINE COMMENT BLOCK
       THAT ONLY ENDS WHEN YOU GET TO THE FOLLOWING SYMBOL PAIR
    */

    echo 'This would also be printed out';
 ?>
 

• as shown above, there are a number of ways to include comments in PHP code

Outputing in PHP

There are essentially two ways of outputting in PHP - echo and print - there is very little difference between the two - at the high-performance end of PHP, echo is fractionally faster, however print can be used in complex expressions - for the basic level of PHP there is no difference.

 <?
    echo 'Hello';
    echo "World";
    print 'Where are';
    print "you?";
 ?>
 

• all of the above are valid examples of outputting

Which symbol to use ' or "?

Again, these are essentially the same.

How do I print a ' or " in my output?

This is a very important note, that often causes problems for the novice PHP programmer.

If you try and do this:

 <?
    echo "My name is "Matthew" - yes it is!";
 ?>
 

You would probably expect the output to be:

 My name is "Matthew" - yes it is!
 

But what you will actually get is something like:

To output speech marks, either single (') or double (") in echo or print statements you must ESCAPE them

Escaping Speech Marks

To ESCAPE speech marks, you put a backslash symbol only in front of the ones you want to print out.

So the example in the previous section becomes:

 <?
    echo "My name is \"Matthew\" - oh yes it is!";
 ?>
 

And the output you get is:

 My name is "Matthew" - oh yes it is!
 

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PHP104 - PHP Variables