Conditional Statements in PHP code Between HTML Code - php

I'm having a bit of an issue by using Conditional Statements in PHP separated by HTML code. This is the type of code I'm trying to write. This is a profile page and it should only be seen by the user whose profile it is (i'm using session variables for checking that) :
<?php if(check if user is logged in) ?>
<display users profile in html>
<?php else ?>
<display an error>
But this doesn't work. I also tried using the shorthand notation by putting a : at the end of the if and using the endif statement, but it didn't work. ( On an earlier project , the : method worked for foreach and endforeach so I thought I would try it out )
Any Ideas ?

You probably forgot the endif of the alternative control structure syntax:
<?php if(check if user is logged in): ?>
<display users profile in html>
<?php else: ?>
<display an error>
<?php endif; ?>
Omitting the braces as you wrote is not possible. It is only possible if it is followed by a regular statement.

PHP has two styles of notation for if() blocks (and blocks in general).
Firstly, you have the wordy notation, which involves explicitly stating endif; at the end of the if() block. It looks like this:
if(whatever):
do something
else:
do something else
endif;
The colons at the end of the if and else lines are important, because otherwise PHP thinks you're using the other notation (below).
Secondly, you have the curly-braces notation, which looks similar to C or Perl style code, and looks like this:
if(whatever) {
do something
} else {
do something else.
}
With this style notation, you are allowed to leave the pairs of curly-braces off if your block is only going to be one line long. (I personally think it's bad practice to leave them off like this, but plenty of people swear by it, and it is perfectly valid syntax. But I've seen PHP get confused over single-line blocks when you're switching between PHP code and HTML; this is why I always prefer to use braces even if I'm only writing one line).
The problem in your case is that you've mixed the two notations. You's trying to us the wordy notation, but don't have the colons on the lines, so PHP thinks you mean the braces notation. But because the braces notation allows for the braces to be missed out, PHP is seeing your code as valid syntax, even if it isn't going to work quite as you planned.
Your solution is to tidy it up so that you are definitely using one syntax or the other. Either add braces ({ and }}) to the start and end of each block as shown in my example, or add colons and an endif; line.
So your code should look like one of these two examples:
<?php if(check if user is logged in): ?>
<display users profile in html>
<?php else: ?>
<display an error>
<?php endif; ?>
or...
<?php if(check if user is logged in) { ?>
<display users profile in html>
<?php } else { ?>
<display an error>
<?php } ?>
Hope that helps.

use braces { and }.
<?php if(check if user is logged in) { ?>
<display users profile in html>
<?php } else { ?>
<display an error>
<?php } ?>

Another way to conditionally render a template is by using include
Example
if($condition)
{
include 'page1.php';
}else{
include 'page2.php';
}

Your initial thought was correct. There are two ways of doing this, as per the PHP documentation:
<?php if($loggedin): ?>
<p>User is logged in.</p>
<?php else: ?>
<p>User is not logged in.</p>
<?php endif; ?>
Or:
<?php if($loggedin){ ?>
<p>User is logged in.</p>
<?php }else{ ?>
<p>User is not logged in.</p>
<?php } ?>

Try putting in brackets to separate the conditions.
<?php if(check if user is logged in) { ?>
<display users profile in html>
<?php } else { ?>
<display an error>
<?php } ?>

use brackets because to the php interpreter this spans multiple lines
<?php if(check if user is logged in) { ?>
<display users profile in html>
<?php } else { ?>
<display an error>
<?php } // else ?>

Related

open&close php tags on each line, within arrays, functions

I collaborate with a web-programmer on a php project based in kirby cms, and he wants to open and close every line as such:
<main>
<?php /*php code here/* ?>
<?php /*more php here*/ ?>
...
Trying to follow this style, I found some errors in my code. The first is that it seems I canNOT do this in the middle of an array as such:
BAD CODE
<?php $oo = array( ?>
<?php 'h' => 100, ?>
<?php 'v' => 100, ?>
<?php ); ?>
but I can do it in the middle of a foreach loop as such:
<?php foreach ($p as $subp): ?>
<div id='<?= $subp->title() ?>'>
<?php endforeach; ?>
Are there any other cases such as array in which I canNOT do this?
/edit
According to the answer, there can only be tag-breaks within 'foreach', 'while', or 'if' blocks.
How about a 'foreach', 'while' or 'if' within a function? is that 'legal'?:
<?php
function myFunction($arg){
if($arg === 'this'): ?>
<?= '<p>yep</p>' ?>
<?php else: ?>
<?= '<p>nop</p>' ?>
<?php endif;
};
?>
And how about nesting if within foreach within function?:
<?php
function myFunction($arr){
foreach($arr as $val): ?>
<p><?= $val ?> <p>
<?php if($val === 'this'): ?>
<?= '<p>yep</p>' ?>
<?php else: ?>
<?= '<p>nop</p>' ?>
<?php endif;
endforeach;
};
?>
edit/
Thank you
you cannot "break out of php" mid statement. wline defining an array for example you cannot close the php tags. The only time when you can "break out" of php is between opening and closing a loop or an if/else statement. This actualy does not break the statement as <?php foreach: ?> is a complete statement whereas <?php foreach{ ?> is not. Here some examples of what you can do:
<?php if($this!=$that): ?>
{something}
<?php endif ?>
<?php foreach($things as $thing): ?>
{something}
<?php endforeach ?>
<?php $while($this): ?>
{something}
<?php endwhile ?>
I think you get the message. you must have complete statements within php tags, without interruptions.
P.S. Also avoid using the shorthand <? instead of <?php at all cost, moving your project to a different hosting or an upgrade of your hosting might break your project as per default short tags are not activated. <?= ?> shorthand is safe as this is unaffected by the setting for newer php versions.
P.P.S Do not listen to the guy who wants php in one line, this will make your code hard to read and maintain. Stand strong and write beautiful code :)
UPDATE: (after the update on the question from #Jaume Mal)
I did not mean the examples in my answer as exclusive but as examples of statements that are complete vs statements that are incomplete. (I also forgot to mention closing php tags mid fuction, wich also work but I despise and woudl strongly advise against.) So for example <?php function foo(){ is a complete statement of starting a function but (as the other cases with loops etc..) it needs a closing statement, in this case }. This is true for if / else or foreach and so on:
<?php if($this){ ?>
some code
<?php } ?>
is a valid code, as the code pieces within the php tags are complete statements.

Which is the correct way to write an IF statement of these two? [duplicate]

Are there any differences between...
if ($value) {
}
...and...
if ($value):
endif;
?
They are the same but the second one is great if you have MVC in your code and don't want to have a lot of echos in your code. For example, in my .phtml files (Zend Framework) I will write something like this:
<?php if($this->value): ?>
Hello
<?php elseif($this->asd): ?>
Your name is: <?= $this->name ?>
<?php else: ?>
You don't have a name.
<?php endif; ?>
At our company, the preferred way for handling HTML is:
<? if($condition) { ?>
HTML content here
<? } else { ?>
Other HTML content here
<? } ?>
In the end, it really is a matter of choosing one and sticking with it.
They are indeed both the same, functionally.
But if the endif is getting too far from the correspondent if I think it's much better practice to give a referencing comment to it. Just so you can easily find where it was open. No matter what language it is:
if (my_horn_is_red or her_umbrella_is_yellow)
{
// ...
// let's pretend this is a lot of code in the middle
foreach (day in week) {
sing(a_different_song[day]);
}
// ...
} //if my_horn_is_red
That actually applies to any analogous "closing thing"! ;)
Also, in general, editors deal better with curly brackets, in the sense they can point you to where it was open. But even that doesn't make the descriptive comments any less valid.
Here's where you can find it in the official documentation: PHP: Alternative syntax for control structures
I think that it's particularly clearer when you're using a mix of ifs, fors and foreaches in view scripts:
<?php if ( $this->hasIterable ): ?>
<h2>Iterable</h2>
<ul>
<?php foreach ( $this->iterable as $key => $val ):?>
<?php for ( $i = 0; $i <= $val; $i++ ): ?>
<li><?php echo $key ?></li>
<?php endfor; ?>
<?php endforeach; ?>
</ul>
<?php elseif ( $this->hasScalar ): ?>
<h2>Scalar</h2>
<?php for ( $i = 0; $i <= $this->scalar; $i++ ): ?>
<p>Foo = Bar</p>
<?php endfor; ?>
<?php else: ?>
<h2>Other</h2>
<?php if ( $this->otherVal === true ): ?>
<p>Spam</p>
<?php else: ?>
<p>Eggs</p>
<?php endif; ?>
<?php endif; ?>
as opposed to:
<?php if ( $this->hasIterable ){ ?>
<h2>Iterable</h2>
<ul>
<?php foreach ( $this->iterable as $key => $val ){?>
<?php for ( $i = 0; $i <= $val; $i++ ){ ?>
<li><?php echo $key ?></li>
<?php } ?>
<?php } ?>
</ul>
<?php } elseif ( $this->hasScalar ){ ?>
<h2>Scalar</h2>
<?php for ( $i = 0; $i <= $this->scalar; $i++ ){ ?>
<p>Foo = Bar</p>
<?php } ?>
<?php } else { ?>
<h2>Other</h2>
<?php if ( $this->otherVal === true ){ ?>
<p>Spam</p>
<?php } else { ?>
<p>Eggs</p>
<?php } ?>
<?php } ?>
This is especially useful for long control statements where you might not be able to see the top declaration from the bottom brace.
I think that it really depends on your personal coding style.
If you're used to C++, Javascript, etc., you might feel more comfortable using the {} syntax.
If you're used to Visual Basic, you might want to use the if : endif; syntax.
I'm not sure one can definitively say one is easier to read than the other - it's personal preference. I usually do something like this:
<?php
if ($foo) { ?>
<p>Foo!</p><?php
} else { ?>
<p>Bar!</p><?php
} // if-else ($foo) ?>
Whether that's easier to read than:
<?php
if ($foo): ?>
<p>Foo!</p><?php
else: ?>
<p>Bar!</p><?php
endif; ?>
is a matter of opinion. I can see why some would feel the 2nd way is easier - but only if you haven't been programming in Javascript and C++ all your life. :)
I would use the first option if at all possible, regardless of the new option. The syntax is standard and everyone knows it. It's also backwards compatible.
Both are the same.
But:
If you want to use PHP as your templating language in your view files(the V of MVC) you can use this alternate syntax to distinguish between php code written to implement business-logic (Controller and Model parts of MVC) and gui-logic.
Of course it is not mandatory and you can use what ever syntax you like.
ZF uses that approach.
There is no technical difference between the two syntaxes. The alternative syntax is not new; it was supported at least as far back as PHP 4, and perhaps even earlier.
You might prefer the alternative form because it explicitly states which control structure is ending: endwhile, for example, can only terminate a while block, whereas if you encounter a brace, it could be closing anything.
You might prefer the traditional syntax, though, if you use an editor that has special support for braces in other C-like syntaxes. Vim, for example, supports several keystrokes for navigating to matching braces and to the starts and ends of brace-delimited blocks. The alternative syntax would break that editor feature.
In the end you just don't want to be looking for the following line and then having to guess where it started:
<?php } ?>
Technically and functionally they are the same.
It all depends, personally I prefer the traditional syntax with echos and plenty of indentations, since it's just so much easier to read.
<?php
if($something){
doThis();
}else{
echo '<h1>Title</h1>
<p>This is a paragraph</p>
<p>and another paragraph</p>';
}
?>
I agree alt syntax is cleaner with the different end clauses, but I really have a hard time dealing with them without help from text-editor highlighting, and I'm just not used to seeing "condensed" code like this:
<?php if( $this->isEnabledViewSwitcher() ): ?>
<p class="view-mode">
<?php $_modes = $this->getModes(); ?>
<?php if($_modes && count($_modes)>1): ?>
<label><?php echo $this->__('View as') ?>:</label>
<?php foreach ($this->getModes() as $_code=>$_label): ?>
<?php if($this->isModeActive($_code)): ?>
<strong title="<?php echo $_label ?>" class="<?php echo strtolower($_code); ?>"><?php echo $_label ?></strong>
<?php else: ?>
<?php echo $_label ?>
<?php endif; ?>
<?php endforeach; ?>
<?php endif; ?>
</p>
<?php endif; ?>
I used to use the curly braces but now a days I prefer to use this short-hand alternative syntax because of code readability and accessibility.
Personally I prefer making it in two seperate sections but within the same PHP like:
<?php
if (question1) { $variable_1 = somehtml; }
else { $variable_1 = someotherhtml; }
if (question2) {
$variable_2 = somehtml2;
}
else {
$variable_2 = someotherhtml2;
}
etc.
$output=<<<HERE
htmlhtmlhtml$variable1htmlhtmlhtml$varianble2htmletcetcetc
HERE;
echo $output;
?>
But maybe it is slower?
I think it's a matter of preference. I personally use:
if($something){
$execute_something;
}
I used to use curly brackets for "if, else" conditions. However, I found "if(xxx): endif;" is more semantic if the code is heavily wrapped and easier to read in any editors.
Of course, lots editors are capable of recognise and highlight chunks of code when curly brackets are selected. Some also do well on "if(xxx): endif" pair (eg, NetBeans)
Personally, I would recommend "if(xxx): endif", but for small condition check (eg, only one line of code), there are not much differences.
I feel that none of the preexisting answers fully identify the answer here, so I'm going to articulate my own perspective. Functionally, the two methods are the same. If the programer is familiar with other languages following C syntax, then they will likely feel more comfortable with the braces, or else if php is the first language that they're learning, they will feel more comfortable with the if endif syntax, since it seems closer to regular language.
If you're a really serious programmer and need to get things done fast, then I do believe that the curly brace syntax is superior because it saves time typing
if(/*condition*/){
/*body*/
}
compared to
if(/*condition*/):
/*body*/
endif;
This is especially true with other loops, say, a foreach where you would end up typing an extra 10 chars. With braces, you just need to type two characters, but for the keyword based syntax you have to type a whole extra keyword for every loop and conditional statement.

Alternative syntax for control structures in PHP

I have a very short code snippet but I have been unable to get the result I want. The code is as shown
<?php
$user = true;
if($user==true): ?>
<p>you are already logged in</p>
<?php else: ?>
<p>User value is not set</p>
<?php endif; ?>
on running the code it gives this error:Parse error: syntax error, unexpected 'else' (T_ELSE)
What might be the problem?
It could be a problem with your editor. I had similar problems (more than once) with Atom.
To solve, I just copied the file contents, closed it, reopened, pasted the contents and saved.
The code is fine, as others mentioned in the comments. You should try out this.
#lil your code is looks right only, this is alternate way to get same output if you like you can try this.
<?php
$user = true;
if($user==true)
{
?>
<p>you are already logged in</p>
<?php
}
else
{
?>
<p>User value is not set</p>
<?php
} ?>

Is there harm in outputting html vs. using echo?

I have no idea really how to say this, but I can demonstrate it:
<?php
if (true) {
echo "<h1>Content Title</h1>";
}
?>
vs
<?php if (true) { ?>
<h1>Content Title</h1>
<?php } ?>
What differences are there between the two? Will there be problems caused by not using echo? It just seems super tedious to write echo "html code"; all the time, specially for larger segments of html.
Also, bonus kudos to someone who can rephrase my question better. :)
There's a small difference between the two cases:
<?php
if (true) {
echo "<h1>Content Title</h1>";
}
?>
Here, because you're using double quotes in your string, you can insert variables and have their values rendered. For example:
<?php
$mytitle = 'foo';
if (true) {
echo "<h1>$mytitle</h1>";
}
?>
Whereas in your second example, you'd have to have an echo enclosed in a php block:
<?php if (true) { ?>
<h1><?php echo 'My Title'; ?></h1>
<?php } ?>
Personally, I use the same format as your second example, with a bit of a twist:
<?php if (true): ?>
<h1><?php echo $mytitle; ?></h1>
<?php endif; ?>
I find that it increases readability, especially when you have nested control statements.
There are no relevant differences performance-wise. But you won't be able to use variables in the latter, and it looks less clean IMO. With large blocks, it also becomes extremely difficult to keep track of {} structures.
This is why the following alternative notation exists:
<?php if (true): ?>
<h1>Content Title</h1>
<?php endif; ?>
it's marginally more readable.
This:
<?php if (true) : ?>
<h1>Content Title</h1>
<?php endif; ?>
This is the way PHP is supposed to be used.
Don't echo HTML. It's tedious, especially because you have to escape certain characters.
There may be slight performance differences, with the above probably being faster. But it shouldn't matter at all. Otherwise, no differences.
I appreciate all the feedback. :)
I did find out some issues when using the two different methods.
There does not appear to be any real issue here except that the formatting looks terrible on the source and the tedious nature of it.
<?php
if (true) {
echo "<h1>Content Title</h1>";
}
?>
Using php this way can cause an error as such
Warning: Cannot modify header information - headers already sent
<?php if (true) { ?>
<h1>Content Title</h1>
<?php } ?>
The headers error can possibly be solved by using php like so
<?php ob_start(); if (true) { ?>
<h1>Content Title</h1>
<?php } ob_end_flush(); ?>
As to why and when the headers are sent, I am not completely sure...

PHP usage easy for template's

Actually i once saw some PHP code on php.net but i forgot its name or usage.
It is something may be related to heredoc (may be not)
What i am trying to achieve is to do HTML inside php IF conditions..
it was somthing like
xhtml code here
i hope u understand what i am trying to ask!
thanks for your help.
If you're referring to the alternative syntax for control structures, it's something like this:
<?php if ($a == 5): ?>
<div>A is equal to 5</div>
<?php endif; ?>
Reference: http://php.net/manual/en/control-structures.alternative-syntax.php
http://php.net/manual/ru/language.types.string.php#language.types.string.syntax.heredoc
http://php.net/manual/en/function.ob-get-clean.php
<?php
/** Other PHP code */
$is = true;
?>
<?php ob_start(); ?>
<h3>Caption</h3>
<?php if($is): ?>
...some text 1
<?php else: ?>
...some text 2
<?php endif; ?>
<?php $out = ob_get_clean(); ?>
<?php
/** Other PHP code */
echo $out;
?>

Categories