![]() You see the subtle difference? Empty picks all those conditions up, while isset says that "", 0, "0" are true, not what you normally want. This is probably not something you want to always remember to do, especially with forms.Įmpty() says that " ", 0, "0", NULL and "not set" are TRUE. ![]() and that was a problem, and Isset() said NULL and "not set" were FALSE, so we would need to remember to set variables we don't want set to NULL or not declared to get consistent results. Wait a minute! Isset() said that " ", 0, and "0" were TRUE. None of these have a specific value, and when compared to !empty() would be FALSE, which is what you want. When you use "! EMPTY()", the following variable values would all come up FALSE, or verify that the variable is not set: " ", 0 as an integer, "0" as a string, NULL, array() - an empty array, and a variable declared, but not assigned a value. Not empty means that the variable is not zero or blank, or not empty. If the variable is not empty, go to movies.php. Here's a "Not empty() example: if( !empty($menuChoice2) ) How do we protect ourselves from these inadvertent TRUE's? Well, there is an "EMPTY()" condition, and a "NOT EMPTY()" condition, we can use. These values, although they may look blank, have value, and the isset() conditional will say so, and be TRUE, when you may have thought the variable was blank, and you wanted a FALSE evaluation. The same for the integer value 0, which is also TRUE. If you have a text input, or a textarea input, from your form, and nothing is in the box when submitted, that variable is set to " ", and isset() will say it's TRUE. That means variables assigned a " " ,or 0 ,or "0" are set, and therefore TRUE for isset(). ISSET() checks the variable to see if it has been set, or checks to see if the variable is any value except not assigned a value, or NULL. This will take you to the popcorn.php view, if $menuChoice2 was selected on the previous view, and here's where you can run into problems, since the way your using "isset($menuCHoice2)" may make it always be TRUE. This is done with an "if" or "switch" statement, like this: if( isset($menuChoice2) ) After that, you process the data and do something with the data.įinally, we come to the section, where we decide what the next view should be. ![]() If it's a variable, the next thing you unusually do is validate the the data is what you expected, and not some hacker trying to get into your system. This could be a menu selection, or a variable, probably set by the "name" property in an "input" tag of the form. First, you get the data in from the form with either the $_GET or $_POST command, like this: $MenuChoice2 = $_POST If you look at a lot of controller code, you begin to see constructs that follow a pattern. Let's try to straighten any confusion out. The usual culprit is the ISSET condition. Why? If it passes an empty value, then why use it? Why just not use empty? But in all programs I see solution like this.A problem that I have run into a couple of times in getting results back from forms to the controller, and then going to another view, is that, for some reason, the conditional I set to go to a particular view did not function properly, and I would go somewhere else. I didn't enter anything but the function said that the variable was set to a value other than NULL. ![]() Your name is (and does NOT print "Enter your name") What's your name? (and the submission form) Your name (Enter your name) What is your name? (and the submission form)ĭid not enter nothing at all, then hit "send" - it prints: That's what I do not understand: I open this page - it prints: In the third line we have a condition: if it's not set, the script prints 'enter your name'. In the second line we check is variable set or not with isset().
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