php Symbol Reference

zipadyduda

I have spent days looking in the php reference manual, in books, and on the net. But I can't find a single quick reference guide to the characters used in php.

What I want is a list of all characters and what they do.

For example

$ is used for a) define a variable b) wildcard at the end of a string. ...
? is used for ....

is used for ...

There are plenty of reference lists for the word commands. why is there no list of all the characters?

planetsim

There isnt any characters that do anything. your

is a shell style comment which isnt really a PHP thing but was thrown in there because of its Perl Ties.

? is more a regex thing than PHP however you can do this

[php
$var=($d==2)?2:-1;
[/code]

If your not sure what that means think of it like this

if ($d==2) {
  $var = 2;
} else {
  $var = -1;
}

Its just a quicker and from what i see more efficient form. However make sure you show consistency when doing it.

You may want to read up about Regular Expressions (regex).

http://au3.php.net/manual/en/ref.pcre.php

zipadyduda

Thanks for taking the time to reply, but I think you misunderstood.

Imagine trying to learn a language. There are plenty of dictionaries but no lists of punctuation. A ? in English doesn't do anything either but you need it because it indicates a question. Try looking up that in a dictionary. What does it indicate in php? And what about all the other symbols.

I'm at the bottem of the learning curve and I don't think I'm alone in my frustration that all reference materials take it as a given that you understand that stuff.

in your example you used even more symbols.

;
(

{

and [

what's the difference between ( { and [
when do you use which one

and again, why does it not exists a list of all symbols and what they're for?

yelvington

The manual is extremely complete and well-organized, but it does assume that you have at least looked at a programming language before. PHP uses semicolons, parentheses, and braces pretty much the same way they are used in a dozen other languages including C, Java, ECMAscript, Perl and most shell scripting.

You can't just put together a list of symbols and meanings because those meanings will change depending on context. For example:

echo (4 == 5 ? 'true' : 'false');

<?php echo 'Hello? Are you there?'; ?>

preg_match('/doo?dah/', $foo);

In each of these cases, the '?' character has a completely different meaning.

You need to tackle this issue from another angle. Learn to recognize patterns.

zipadyduda

Programmers are the dumbest smart people on earth. And this is after all the newbie section which makes me even dumber then that. So maybe someone can humor me with the simple truths that I seek.

Why can't anyone understand that this stuff is complete giberish without knowing what the symbols do and that knowledge is proprietery and deserves explaination?

You said that they are "pretty much" the same...
Unlike human language, there is no ambiguity in computer languages. There is a definate meaning for everything.
Looking at patterns, I don't believe that there are an infinate number of uses for each symbol. If that were the case they would be interchangeable and it wouldn't matter what symbol is used at any given point.

Therefore, even if each symbol has a thousand different contexts, it is not impossible to compile a list of the symbols and thier uses and it therefore can be done and should. Someone could make a lot of money by simply typing it out and sending it to a publisher because I also can't believe that I'm the only fool out there that wants to know.

So the fact remains that these symbols have definate meaning (depending on context) and yet there does not exist a reference for them.

My search continues. Is it a conspiracy?

TheDefender

You seek simple truths, and the bottom line is this:

There are no simple truths when it comes to programming languages... Only complex ones, as evidenced by planetsim's and yelvington's examples on usage of the ?. Nope, it's not a conspiracy... Read on.

You are at the right place when it comes to learning PHP. These forums are EXTREMELY helpful when it comes to learning, but even with the newbie section, there is a basic assumption that you have worked with other programming languages in the past, because most of us have. If you are a newbie to programming languages as a whole, then yes... you are at the bottom of the learning curve, but all is not lost.

Use these forums, in conjunction with the manuals, and you will learn a bunch.

Hey, here's an idea... You can compile the list of the various usages of punctuation, and create an article or tutorial for it. That would be a great place to start for you... The rest of us have started from virtually no PHP language knowledge, and have just "learned to use them" through trial and error, but your article could be very useful for the thousands of newbies out there...

laserlight

Why can't anyone understand that this stuff is complete giberish without knowing what the symbols do and that knowledge is proprietery and deserves explaination?

They arent proprietary since PHP isnt proprietary, but they are arbitrary.

it is not impossible to compile a list of the symbols and thier uses and it therefore can be done and should

Yes, it is possible, though I dont know of any such comprehensive list.
On the other hand, the PHP manual does have a list of functions and other keywords.
Other than that, symbols are introduced progressively (e.g. related symbols are listed together, but that's because they are related, e.g. operators, regex symbols), not simply listed for the sake of a list.

So the fact remains that these symbols have definate meaning (depending on context) and yet there does not exist a reference for them.

Well, it possible that a reference (perhaps partially complete) exists, but isnt widely used because most of us have learnt step by step, and so covered enough ground to get us going.
When we come across something new, we start looking around the manual, experimenting by ourselves, searching the Web etc for more information on it.

zipadyduda

In the course of this thread so far, nobody has told me comprehensively what one single symbol is for.

Everyone seems to know, but they don't know how to explain or don't want to.

What you're telling me is if I want to learn Chinese, I should go to China and read signs to get on trains and after I get on enough of the wrong trains I'll learn Chinese because that's how everyone else does it.

laserlight

In the course of this thread so far, nobody has told me comprehensively what one single symbol is for.

Because there is no point in specific cases.
The truth is out there, or rather the material is out there.
Read the PHP Manual at php.net, for example.

What you're telling me is if I want to learn Chinese, I should go to China and read signs to get on trains and after I get on enough of the wrong trains I'll learn Chinese because that's how everyone else does it.

No, I'm telling you to learn some basic words first, and then learn to construct a sentence, where the grammar and punctuation will come in.
After that, attempt elementary texts on and/or in Chinese, with the aid of a dictionary, and other references, perhaps even a teacher.

laserlight

There are plenty of reference lists for the word commands. why is there no list of all the characters?

There is good reason why there is a function reference: programmers often forget the parameters of a given function, or even its return type.
This is effectively a dictionary: one may forget the spelling or pronunciation of a word, especially when it may be quite arbitrary.
On the other hand, rules of grammar and punctuation are far less likely to be forgotten.

Frankly, there is no point debating this.
Just learn step by step, and you'll find that you will be able to absorb the language better.

Roger_Ramjet

The technical answer is that PHP is 'overloaded'. This means that symbols and expressions, punctuation and sentence structure, vary in their meaning according to context.

There is no short way to learn a language, be it French or PHP.

You start like a baby, you look and listen, or in this case read a book, and experiment. You find the uses and limitations of the language through trial and error. After a certain point, you know enough of the language to discuss it meaningfully, then you can learn form those with a better command of the language.

The best advise I can offer is this:

PHP falls into a 'group' that I think of as C. I mean that it looks the same as C, or JAVA and others. Once you have learnt one you will find the others easier to pick up. Which is no help the first time around. But you will find many more books, courses and information around for C: it has been around longer.
Try this link: http://www.sitepoint.com/books/Kevs-php-mysql.pdf

You can download 4 chapters form a book on PHP/MySQL by Kevin Yank that will help you get started even if you don't know what is going on half the time.

NO-ONE knows everything about any programming language. That is the continuing facination for some of us.

TheDefender

Originally posted by zipadyduda
In the course of this thread so far, nobody has told me comprehensively what one single symbol is for.

I think everyone's responses have been more than sufficient to answer your question... You just gotta do it and learn...

OK, wait, here's one for you...

The period (.) is used to end a sentence.
echo "Hello.";
Oh wait, it's used to concatenate...
$variable = Hello." ".$noun;

Oh, heck... maybe, I will look at the comma instead, because all it does is seperate portions of a sentence.
echo "Hello, can I help you?";
Oh wait, it's used to separate values in an array.
$array = array("John", "Dave", "Jerry");

Oh, dangit, there's just too much to know... I think I am going to get mad at the world for not explaining EXACTLY what these symbols do... Do you see how silly you are being? It is one of those things that NOBODY has ever told us about. We just learned it!

zipadyduda

I suppose you learned how to drive with nobody telling you what a red light means? Just start driving and you'll figure it out.

zipadyduda

Here's an example of what I'm talking about.

The very first tutorial in the php manual is this

<html>
<head>
<title>PHP Test</title>
</head>
<body>
<?php echo '<p>Hello World</p>'; ?>
</body>
</html>

What is not included in the tutorial is this...

< > signals the beginning and end of a command and that there
are commands inside other commands.

/ signals the end of a command

Was that so hard to explain? Because experienced people think it's obvious is a bad reason to leave it out of an introductory tutorial.

Roger_Ramjet

Wrong! < and > are nothing to do with PHP: they are HTML. Which is probably why they are not explained in the manual. HTML tags are enclosed in < ... >, they are the instructions passed to your browser to tell it how to find, format, and present a web page.

PHP is used to, amongst other things, extract data from a database and generate the HTML to display it in a browser. So what you are looking at in your example is a mixture of HTML & PHP. The only bit that is PHP is


<?php echo ' ... '; ?>

Now, php was specific ......

Hey, hang on a minute! This thread is a wind-up isn't it zipadyduda? If you don't know html then forget php.

TheDefender

Originally posted by zipadyduda
I suppose you learned how to drive with nobody telling you what a red light means? Just start driving and you'll figure it out.

The difference is that when you are driving, you recognize what that red light means... It starts at a young age when you are in the back seat, and you ask you parents, or when you notice a pattern (hhhmmmmmm, sound familiar?) that everytime you were at a red light, or approached one, you stopped...

Well, as you progress through your PHP learning, you will notice patterns (there's that word again), and you can ask your surrogate parents here, and we'll show you how things work.

Like I said before, if you want some sort of "Guide to Punctuation", then write one. As you try to do it, you will begin to understand why we can't just spat out the exact meaning of a question mark or period... which is probably why nobody (even the pros) have ever tried.

laserlight

Was that so hard to explain? Because experienced people think it's obvious is a bad reason to leave it out of an introductory tutorial.

But what does "h" mean?
basically, you have forgotten something else: a letter of the English language was used, yet you did not explain it.
What about "head"?
Now a word in the English language was used, yet you did not explain it.

Now I shall say to you:
Was that so hard to explain? Because experienced people think it's obvious is a bad reason to leave it out of an introductory tutorial.

TheDefender

A few Good Men
Caffee: Wait, so you mean to tell me that in all the time you lived in Gitmo, you've never eaten a meal.
Corporal: No sir, three squares a day.
Caffee: Well how did you know where to go eat if it's not in the manual.
Corporal: I guess I just followed the crowd at Chow time.

Follow the crowd at Chow Time zip!!!

laserlight, that was profound... You still have me thinking about that one! 😉

zipadyduda

I finally found what I was looking for.

http://weblogtoolscollection.com/regex/regex.php

czambran

I have been following this thread and zipadyduda you should try to listen a little bit more(or should I say read a little bit more), these are people who have a lot of experience working with php. I do not see how the page for which u have posted the link answers your question. That site mainly talks about regular expressions, a subject for which you could have found a thorough explanation on the php manual. I am also a noob and let me tell u it hasn't been easy but the people form phpbuilder has sure kept me motivated because everytime I got stuck they were there to help kind of as parents when you are just learning to walk.

Instead of trying to know everything from the start, learn some, test it, if you have questions about something, ask it. But you want a dictionary without knowing how to read.

Just my 2 cents.