Ok, then let's start from the top:
1. foreach
Foreach is a language construct used to loop over an entire array
returning the (key and) value on each iteration. So:
$a = array('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5,'f'=>6);
foreach($a as $key=>$value) {
echo $key.' = '.$value;
}
will return
a=1
b=2
etc.
Basically it's almost the same as a for() loop but with less hassle and
you don't need to know exactly how long it is. And one very important
aspect here is that foreach works on both numeric indices AND
non-numeric! Unlike for() which only works with numbers (in a "normal"
setting).
$a += $b;
is short for $a = $a+$b;
What I do here is I make the function recursive, ie. call itself from
itself. A common example given is one to calculate faculty:
function faculty($i) {
if($i <= 1) {
return 1;
} else {
return $i*faculty($i-1);
}
}
faculty(3) returns: 6 because:
faculty(3):
if(3 <= 1) {
// won't run
} else {
return 3*faculty(2);
/*
faculty(2) runs:
return 2*faculty(1)
faculty(1): return 1;
*/
}
And the last, if you don't know what is_array() does, then please open a
dictionary and lookup the word "is".
So, what my example did was:
1. check if we were passed an array or not.
1.1 if it was an array, loop over the array and call this function on
each element and add all returned values into 1 variable.
1.2 if it was NOT an array, compute the tax for that number and return it.
You will notice that in PHP it is often much easier to use the foreach()
construct than a for() loop because there's much less hassle. (like in
your last post where you had problems with your for loop).
Make sure to read the following pages from the manual:
1. Foreach construct:
http://www.php.net/manual/en/control-structures.foreach.php
2. Operators: http://www.php.net/manual/en/language.operators.assignment.php
3. Arrays: http://www.php.net/manual/en/language.types.array.php
Jacob Bergman wrote:
Thanks, unfortunately, I don't really know what the whole
" if(is_array($State))
{
$total = 0;
foreach($State as $s)
{
$total += ComputeSalesTax($Amt, $s);
}
return $total;"
don't know enough yet to understand what all that means...
I have gotten the function to work the way I want using a for loop in
the function... but it doesn't seem to want to display the 0 keyed value
in the array. If you run this, you'll see what I mean. Can you tell me
what is wrong with it?
----------------------------------------------------------------------
$State = array ("WA" , "CA" , "OR");
function compute_salestax ($Amount , $State)
{
for ($i = 0 ; $i<= 2/*sizeof($State)*/ ; $i++)
{
switch ($State[$i])
{
case "WA" :
$Rate = "1.07";
break;
case "CA" :
$Rate = "1.08";
break;
case "OR" :
$Rate = "1.05";
break;
}
global $Rate;
$Truetax = ($Amount * $Rate);
echo "$i=";
echo "$Rate | $Truetax <br />";
}}
$Amount = 1850;
compute_salestax($Amount , $State);
---------------------------------------------------------------------
When I run it, I get this
---------------------------------------------------------------------
0= | 0
1=1.08 | 1998
2=1.05 | 1942.5
---------------------------------------------------------------------
Thanks for the help guys!
Jacob Bergman
Network Technician
Pullman School District #267
(509) 432-4012
jbergman@xxxxxxxxxxxxxxxxx
-----Original Message-----
From: M. Sokolewicz [mailto:tularis@xxxxxxx]
Sent: Friday, July 27, 2007 9:34 AM
To: Jacob Bergman
Cc: Jarrett Meyer; php-windows@xxxxxxxxxxxxx
Subject: Re: Arrays past to functions
function ComputeSalesTax($Amt, $State)
{
if(is_array($State))
{
$total = 0;
foreach($State as $s)
{
$total += ComputeSalesTax($Amt, $s);
}
return $total;
}
else {
switch ($State)
{
case "CA":
$tax = 1.05;
break;
case "WA":
$tax = 1.07;
break;
// etc.
default:
$tax = false;
}
if ($tax != false)
{
return ($Amt * $tax);
}
else
{
die("State not found!");
// or some other graceful method...
}
}
}
Jacob Bergman wrote:
Your right, and I have gotten it to work that way, but I wanted to see
how it would be done if I was to use an array. I was trying to do
something easy just so I could "see how it would be done" I guess you
could say. Plus when I run the function, I want it to output the
total
price for all states in the array, and not have to call the function
and
pass it a state and amount for each state. Thanks for the reply.
Jacob Bergman
Network Technician
Pullman School District #267
(509) 432-4012
jbergman@xxxxxxxxxxxxxxxxx
-----Original Message-----
From: Jarrett Meyer [mailto:jmtmeyer@xxxxxxxxx]
Sent: Friday, July 27, 2007 8:56 AM
To: PHP Windows List
Subject: Re: Arrays past to functions
You don't really need an array here.
function ComputeSalesTax($Amt, $State)
{
switch ($State)
{
case "CA":
$tax = 1.05;
break;
case "WA":
$tax = 1.07;
break;
// etc.
default:
$tax = false;
}
if ($tax != false)
{
return ($Amt * $tax);
}
else
{
die("State not found!");
// or some other graceful method...
}
}
ComputeSalesTax(2000, "CA");
// returns 2100
ComputeSalesTax(2000, "LA");
// fails
--
Jarrett M. T. Meyer
http://jarrettmeyer.blogspot.com
http://www.jarrettmeyer.com
----- Original Message ----
From: Jacob Bergman <jbergman@xxxxxxxxxxxxxxxxx>
To: php-windows@xxxxxxxxxxxxx
Sent: Friday, July 27, 2007 11:46:19 AM
Subject: Arrays past to functions
Hello all,
I am learning about passing arrays to functions, and am trying to
create a function that will display a total amount for a price for
several states. Say using CA, WA, and OR, and setting there tax rates
at, whatever, say 5%, 7%, and 8% respectively. I want a function I
can
pass the array of states, and tax rates to that will display the total
amount (amount + tax) of say a $1500 purchase. I am trying to use a
switch statement to accomplish this, but I think I may be in over my
head trying to do this with what I have learned so far... Here is the
code I have so far I get 0 every time I run it, try not to laugh...
:-)
Thanks guys.
$State = array ("CA" , "WA" , "OR");
function compute_salestax ($Amount , $State)
{
switch ($State)
{
case "CA" :
$Rate = "1.05";
break;
case "WA" :
$Rate = "1.07";
break;
case "OR" :
$Rate = "1.08";
break;
}
global $Rate;
$Truetax = ($Amount * $Rate);
echo "$Truetax <br />";
}
$Amount = 1500;
compute_salestax($Amount , $State);
Jacob Bergman
Network Technician
Pullman School District #267
(509) 432-4012
jbergman@xxxxxxxxxxxxxxxxx
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