What do these characters do?

Hi,

I keep on seeing these characters in PHP, but I have no idea what they do. I also can't look them up on Google because I don't know what they're called.

Anyway, the 2 expressions (or whatever they are) are:

%s
example: sprintf("INSERT INTO products (`name`, `description`, `user_id`) VALUES ('%s', '%s', %d)", mysql_real_escape_string($product_name, $link), mysql_real_escape_string($product_description, $link),

=>
example: foreach($_GET as $k=>$v)

Will anyone fill me in on what these are, what they do or what they're called?

Thanks a lot!

 

=> is used for arrays, like $foo = array('1' => "Apples", '2' => "Oranges") ;

accessed like $foo['1'] ;
the foreach is taking all the GET parameters and processing them as keys ($k) and values ($v).

http://us3.php.net/manual/en/language.types.array.php covered at that url.


sprintf at php.net (http://us3.php.net/manual/en/function.sprintf.php )

 

sprintf is a function that formats a string using other variables. the first parameter is the format and the other parameters are all the variables. the %s and %d (there are more) are placeholders to a specific type of variable.
for example, if you put %s, the variable is treated as string. %d is treated as integer.
so
sprintf("my name is %s and i'm %d years old", 'yo' . 'av', 10 + 15) will print "my name is yoav and i'm 25 years old"

=> is used to associate a key to a value in an array
PHP's arrays are all associative. in shallowink's example, '1' is associated to "Apples" and '2' to "Oranges".

 

That is the type specifier for functions like sprintf which format a string.

- ads2help

 

Perfect - Thanks a lot everyone. This helped a lot.

 

Hey guys,

One more... can someone post a page that will explain this:

->

example: $fields[$this->name.'.'.$field] = $value;

Thanks again!
-Dan

 

The dot is the concatenation operator. It smushes two or more strings together into one. In this case there are three strings lined up for besmushal: $this->name, a period, and $field.

So if $this->name == 'tomato' and $field == 'sandwich', then it's effectively doing:

$fields['tomato.sandwich'] = $value;

 

Thanks SmallPotatoes.

I'm more concerned about this part:

$this->name

I'm not sure what the -> does. It looks like it returns array values or something... ?

 

$this refers to the current object, and -> is how you reference an object property. If this terminology doesn't make sense, you'd be best off reading about PHP object-oriented programming at http://www.php.net/manual/en/language.oop5.basic.php

 

Perfect. I'll check that out.

Thanks again, SmallPotatoes.