VariablesA variable is an area of memory which is set aside to store information , this is assigned an identifier by the programmer . You can recognise variables in PHP because they are prefixed with the dollar ( $ ) sign . To assign a variable you use the assignment operator ( = ) . Here is an example of this.$name = "shedboy"; $intDaysInWeek = 7;In the first example the variable identifier in this example is $name and the string value "iain hendry" has been assigned to it . In the second example the variable identifier is $intDaysInWeek and the number 7 is assigned to it . Note that in the number example we do not surround the variable with quotes in this way PHP treats this as a numeric value but if we had put quotes round it then PHP would have treated it as a string.Variable NamingThere are some guidelines to follow for naming variables in PHP and these are as follows . 1. All variable names must begin with a letter or underscore character . 2 . The name of the variable can be made up of numbers , letters , underscores but you cant use charcters like + , - , & , £ , * , etc One important thing to note if you are coming from another programming language there is no size limit for variables .Case SensitivityOne thing that causes many hours of hair pulling and anguish is case sensitivity , PHP is case sensitive (some languages are not) . Here is an example of what I mean.<?php $myname = "shedboy"; echo $Myname"; ?>Now we all know what we want to do , declare a variable , assign it the value of "shedboy" and then print this on the screen but in this example we have mis-spelt the variable name , when run the following error is displayed on the screen.Warning: Undefined variable: Myname in D: estsample.php on line 3ExampleUsing your favourite HTML editor enter the following<?php $url = "http://www.programmershelp.co.uk"; $rank = 1; echo "Our favourite site is ".$url; echo "<br>"; echo "It is numbered ".$rank; ?> here is the output you should get Our favourite site is http://www.programmershelp.co.ukIt is number 1 the owner and founder of Programmers help and maxidirectory to name a few
Category : Scripts
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