Example Syntax Confusions

[theDog]

First post in a series, i think...

Originally posted by cgraz

// This means 1 is assigned to $one
$one = "1";

if ($one == '1') {
    echo "This means $one is equal to 1";
}

Why the double quotes in $one = "1"; ? Is that not equivalent to no quotes since it's an integer? And why single quotes in if ($one == '1')?

Just saw this on another website

for ($i=0;$i<10;$i++)

Why isn't there a semicolon after $i++ ?

😕

[cgraz]

Originally posted by the Dog

Why the double quotes in $one = "1"; ? Is that not equivalent to no quotes since it's an integer? And why single quotes in if ($one == '1')?

It's pretty much interchangeable.
// the following expressions are equivalent

$one = 1; 
$one = "1";
$one = '1';

Just a matter of preference. Single and double quotes are important at times if you have quotes around something that is already around double quotes. For example:

echo "<input type='text' name='name' size='20'>";

// which is equivalent to
echo "<input type=text name=name size=20>";

// if i were to use double quotes within double quotes:
echo "<input type="text" name="name" size="20">";

// that would produce a parse error. PHP would see
echo "<input type="
// and the rest would be a lot of parse errors

As for the for statement , it doesn't use a semi colon to end it, but rather uses curly brackets. Same for while, foreach statments.

Example off php.net

for ($i = 1; $i <= 10; $i++) {
    print $i;
}

Same works for if statments

if ($one == '1') {
    echo "do this\n";
} else {
   echo "do that\n";
}

The {} are what open and close the if statement. It's kind of hard to explain, maybe somone else has a better way of putting it.

Cgraz

[theDog]

I'm not too confused about curly brackets. I do have trouble sometimes determining when to use parentheses. I mean, sometimes it seems they're not required for very similar statements where they are. Know what i mean? PHP certainly does, because it complains heartily when it "expects" something that isn't there, or something is there that it doesn't "expect."

And i'm guessing square brackets are only for holding array variables?

My confusion about the semi-colon is i.e.
for ($i = 1; $i <= 10; $i++)
...has a semicolon after the first two statements and not the last. I suppose i could just take it at face value, but it's not intuitive.

Bye the bye, do empty quotation marks represent empty strings? And ergo empty ones wth a space " " represent a space?

Hehe... i did say "first in a series" yes? Don't blame me, blame these tutorial writers who introduce elements without explaining what they're doing, and more importantly, when i should do it too. Sometimes it's intuitive, sometimes it's not, it always slows down the learning process.
😉

[suntra]

I'll try to explain you some things...

[PHP$one = 1; // $one contains a NUMERIC value, which is 1
$one = "1"; // $one contanis a STRING, which is 1[/code]

For the for loop... the semi-colons are used to separate condition...
for(<initial_condition>;<final condition>;<step>) {
...
}

It's like if you had three different parts in a string separated by a semi-colon. It's unuseful to put a semi-colon at the end...

part 1;part 2;part 3

If when you split it, you take everything between the beginning and the first semi-colon and name that part 1. After, you take everything between the first semi-colon and the second, and you call that part 2. Finally, you take everything between the second semi-colon and the end, and call that part 3.

Also, if you put a semi-colon after the third condition (step), it doesn't look nice !!

for($i = 0; $i < 100; $i++😉 {
}

Look like it's ugly !!! 😉 Yark !! Ok, I know, it's a smiley... but if you put a smiley in that place, you won't have a smile on your face !!!

Is it clearer ?

[theDog]

Well, i have to admit it's a right fine language that can automagically turn syntax errors into winky smilies. Even if it probably took someone 20 hours of syntax errors to get it to do that. 😉

I didn't realize that semicolons were for separating conditions. I thought they were only for ending lines. Why not commas? Which are yet another bug up my :rolleyes:

So anyway, yes, that issue at least is clearer. Thankyou.

=%^}