PHP Strings Primer - echo
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The echo language construct is the most common method used for displaying strings as well as other data. It is very straight-forward and simple to use. The first thing we should notice is that echo is not a function at all. It is a language construct of PHP. What this means to us is that it is not always necessary to use parentheses with echo as it is with functions. for example, the following statement:
Is just as valid as:
In fact, the preferable, and in some cases mandatory, use of 'echo' is without parentheses. This can be demonstrated by an instance where the use of parentheses would be illegal. If you are passing multiple parameters to echo, then it must be done without parentheses, like so:
<?php echo "First String\n", "Second String"; ?> |
The echo construct also provides a shorthand way for displaying content by using a short opening PHP tag immediately followed by an equal sign, then the string to display, and finally closed by a closing PHP tag. A common use for this method is for populating the action field of a HTML form element.
<?php <FORM method=POST action="<?=$_SERVER['PHP_SELF']?>"> ?> |
It is worth noting that this shorthand technique may not work in all situations. If your server administrator has disabled the use of short opening tags for PHP, attempting to use this technique will result in fatal errors.
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