[RESOLVED] changing the value number to =0

balloontrader

I need to do the following

read the following String

$str=" $wspgo[1] $wspgo[2] $wspgo[3] $wspgo[4] $wspgo[5] $wspgo[6] $wspgo[7] $wspgo[8] $wspgo[9] $wspgo[10] $wspgo[11] $wspgo[12] $wspgo[13] $wspgo[14] $wspgo[15] $wspgo[16] $wspgo[17] $wspgo[18] $wspgo[19] $wspgo[20] $wspgo[21]<br> 
$wspmay[1] $wspmay[2] $wspmay[3] $wspmay[4] $wspmay[5] $wspmay[6] $wspmay[7] $wspmay[8] $wspmay[9] $wspmay[10] $wspmay[11] $wspmay[12] $wspmay[13] $wspmay[14] $wspmay[15] $wspmay[16] $wspmay[17] $wspmay[18] $wspmay[19] $wspmay[20] $wspmay[21]<br> 
$wspno[1] $wspno[2] $wspno[3] $wspno[4] $wspno[5] $wspno[6] $wspno[7] $wspno[8] $wspno[9] $wspno[10] $wspno[11] $wspno[12] $wspno[13] $wspno[14] $wspno[15] $wspno[16] $wspno[17] $wspno[18] $wspno[19] $wspno[20] $wspno[21]";

I need to check the value of each $wspgo and if it is >6 then I need to reset the value to 0

I need to check the value of each $wspmay and if it is <7 or >8 I need to reset the value to 0

I need to check the value of each $wspno and if it is <9 then I need to reset the value to 0

What is the best way to do this?

etully

$i=0;
$c=count($wspgo);
while ($i < $c) {
if ($wspgo[$i] > 6) { $wspgo[$i] = 0; }
$i++;
}

Same idea for wspmay and wspno. Leaving it as an exercise for the reader to write those functions.

barand

Then once you have checked the values you can save yourself some coding (provided the arrays have only indexes from 1 - 21) with

$str = join(' ', $wpsgo) . ' ' . join(' ', $wpsmay) . ' '  . join(' ', $wpsno);

balloontrader

Ok I was going to go about this by copying the $wspgo[],$wspmay[*],$wspno[] from $wspd[*]

It looks like I would be better served by creating those in the do loop

$i=0;
$c=count($wspgo);
while ($i < $c) {
if ($wspgo[$i] > 6) { $wspgo[$i] = 0; }
$i++;
}

I think that would look like this

$i=0;
$c=count($wspd);
while ($i < $c) {
if ($wspd[$i] > 6) { $wspgo[$i] = 0
else
$wspgo[$i] =  $wspd[$i];}
$i++;
}

For the $wspmay[*]

$i=0;
$c=count($wspd);
while ($i < $c) {
if ($wspd[$i] <7
or
 $wspd[$i] >8
{ $wspmay[$i] = 0;
else $wspgo[$i] = $wspd[$i] }
$i++;
}

and lastly to get $wspno[*] like this

$i=0;
$c=count($wspd);
while ($i < $c) {
if ($wspd[$i] <9) { $wspgo[$i] = 0
else
$wspgo[$i] =  $wspd[$i];}
$i++;
}

barand

Your else conditions are totally redundant.

If if it isn't in the correct range then change it, otherwise DO NOTHING

balloontrader

barand wrote:
Your else conditions are totally redundant.

If if it isn't in the correct range then change it, otherwise DO NOTHING

The first time $wpsgo[] , $wpsmay[*] , $wpsno[*] are referenced at all
is in the do loops.

If I do not asign the else = $wspd[*] I assum they will be = 0

or shoulf I do a $wspgo[] = $wspd[*] prior to the start of the loop to get it established?

barand

Sorry, please disregard. I didn't read it properly. I assumed yours was an extension of Etully's code

etully

I think what you are trying to do is take ONE set of numbers ($wspd), convert them with the ">6 then 0" filter, display them. And then take the original set of numbers (again $wspd), convert with the "<7 or >8 then 0" filter, and display them. And then take the original set of numbers (again, $wspd), convert them with the "<9 then 0" filter and display them again.

Is that right?

If so, then here's one (of the many) ways to accomplish that:

$wspgo = $wspd;
(do the loop that converts wspgo)
$wspmay = $wspd;
(do the loop that converts wspmay)
$wspno = $wspd;
(do the loop that converts wspno)
then use barand's technique $str = join(' ', $wpsgo) . ' ' . join(' ', $wpsmay) . ' ' . join(' ', $wpsno);

And then display $str

etully

By the way, make sure your syntax is correct on your IF statements.
This is right:
if ($x==1) { $y=4; } else { $y=6; }
This is wrong:
if ($x==1) { $y=4; else $y=6; }
And this is also wrong:
if ($x==1 { $y=4; } else { $y=6; }

barand

You could replace the 3 loops with

foreach ($wspd as $k => $v) {
   $wspgo[$k] = $v > 6 ? 0 : $v;
   $wspmay[$k] = ($v < 7)||($v > 8) ? 0 : $v;
   $$wspno[$k] = $v < 9 ? 0 : $v
}

etully

Well sure, if you wanted to be efficient or something. Sheez!!

🙂

barand

I remember someone in these forums once suggested that people providing solutions should be paid per line of code! I guess I'm destined to remain a pauper.

balloontrader

Ok let me see if I have learned this....

$i=0;
$c=count($wspd);
while ($i < $c) {
$wspgo[$i]=$wspd[$i];
if ($wspgo[$i] > 6) { $wspgo[$i] = 0; }
$i++;
}

$i=0;
$c=count($wspd);
while ($i < $c) {
$wspmay[$i]=$wspd[$i];
if ($wspmay[$i] <7)  { $wspmay[$i] = 0; }
{
if ($wspmay[$i] >8)  { $wspmay[$i] = 0; }
$i++;
}

$wspno=$wspd:
$i=0;
$c=count($wspgp);
while ($i < $c) {
$wspno[$i]=$wspd[$i];
if ($wspno[$i] <9) { $wspno[$i] = 0; }
$i++;
}

$str = join(' ', $wpsgo) . '<br>' . join(' ', $wpsmay) . '<br>' . join(' ', $wpsno);

is the long hand method of getting the results....

$wspgo >6 = 0 else $wspgo = $wspd
$wspmay <7 and >8 = 0 else $wspmay = $wspd
$wpdno <9=0 else $wspno = $wspd

$str = join(' ', $wpsgo) . ' ' . join(' ', $wpsmay) . ' ' . join(' ', $wpsno);
adds the new variables to $str

etully

Well, you're on the right track.

You told us that you have an array called $wspd so we're going to start with that. You want to perform three conversions. The problem is, if you perform the conversion on the $wspd array, then you won't be able to make the 2nd or the 3rd conversion because you won't have the original data to work from.

So far so good.

Therefore, the solution is to make three copies of the original array and perform the conversions on the copies. This way, the original set of numbers never gets screwed up or lost.

The way you make a copy of an array is this: $wspgo = $wspd ;

Now you can do whatever conversions you want on the the $wspgo array without affecting the $wspd array. And the same goes for the other two conversions. Make a copy of the original and perform the conversions on the copy.

And that's why, in an earlier post, I said you want to do this:

$wspgo = $wspd;
(do the loop that converts wspgo)
$wspmay = $wspd;
(do the loop that converts wspmay)
$wspno = $wspd;
(do the loop that converts wspno)
then use barand's technique $str = join(' ', $wpsgo) . ' ' . join(' ', $wpsmay) . ' ' . join(' ', $wpsno);
And then display $str

But then you changed it to this:

$i=0;
$c=count($wspd);
while ($i < $c) {
$wspgo[$i]=$wspd[$i];
if ($wspgo[$i] > 6) { $wspgo[$i] = 0; }
$i++;
}

So your technique is a little like mine but instead of copying the entire $wspd array into the $wspdgo array before the loop starts in one line like this: $wspgo = $wspd; you are doing it one element of the array at a time inside the loop with this: $wspgo[$i]=$wspd[$i];. It's an interesting technique - maybe a little slower. The problem is that with your technique, you're going to need to declare that $wspgo is an array before you start putting elements inside of it. So if you're going to do it your way, you're going to need to put this line before the loop starts:
$wspgo = array();

Also, watch the syntax. In your loop for $wspmay, you put in a stray curly brace.

But you're getting closer.

balloontrader

I was not sure on WHERE to put the $wspgo=$wspgo;

I was assuming that I needed to do one at a time in the loop to get the [*] to incriment.

So this shound be correct then.

$wspgo=$wspd;
$i=0; 
$c=count($wspgo); 
while ($i < $c) { 
if ($wspgo[$i] > 6) { $wspgo[$i] = 0; } 
$i++; 
} 

$wspmay=$wspd;
$i=0; 
$c=count($wspd); 
while ($i < $c) { 
if ($wspmay[$i] <7)  { $wspmay[$i] = 0; } 
if ($wspmay[$i] >8)  { $wspmay[$i] = 0; } 
$i++; 
} 

$wspno=$wspd: 
$i=0; 
$c=count($wspno); 
while ($i < $c) { 
if ($wspno[$i] <9) { $wspno[$i] = 0; } 
$i++; 
} 

$str = join(' ', $wpsgo) . '<br>' . join(' ', $wpsmay) . '<br>' . join(' ', $wpsno);

and works in my test code.

So $wspgo=$wspd: copies the whole array $wspd into an new array called $wspgo

$i=0: sets the value of variable $i to start at 0

$c=count($wspgo); counts the nuber of variables in the array $wspgo

the if statments are filters for the variables and are in ( )

the "then" or "switch" statements are in { } and will either reset the value of the variable or leave it as it is based on the If requirements

$i++; increases the $i variable by 1 and the the loop repeats until $i=$c

$str = join(' ', $wpsgo) . ' ' . join(' ', $wpsmay) . ' ' . join(' ', $wpsno);
adds the new arrays to the end of $str

Am I getting this right so far?

etully

Oh yeah, you've got it. And it's clear that you understand it, which is great.

Everything you said is right so now that you've got the foundation, we can point out a few nitpicks.

First, this is unnecessary:
if ($wspmay[$i] <7) { $wspmay[$i] = 0; }
if ($wspmay[$i] >8) { $wspmay[$i] = 0; }

Instead, you can say:
if ($wspmay[$i] <7 or $wspmay[$i] >8) { $wspmay[$i] = 0; }

When you wrote this:

$i++; increases the $i variable by 1 and the the loop repeats until $i=$c

You were almost exactly right but technically, an array $x with 5 items goes from $x[0] to $x[4]
That is: $x[0], $x[1], $x[2], $x[3], and $x[4] is 5 elements in the array.
So your sentence isn't exactly right. $i++ keeps increasing the variable by one and the loop repeats until $i is one less than $c. But you were getting the right idea.

I use while loops out of habit. A better programmer might use a different loop for that.

And lastly, my instruction assumes that every element is sequentially numbered. That is, 1,2,3,4,5,6,7,8 all the way up to 19,20,21. And that's not a good assumption. I mean, it happens to be true in this case but it won't always be true. So it's better to learn a technique that works whether the elements are sequentially numbered or not.

And a good technique for that is:
foreach ($wspgo as $k=>$v) { }

This way, if the array looks like this:
$wspgo[1] = 17
$wspgo[4] = 7
$wspgo[10] = 1

You can see that there are three elements. And remember that $c=count($wspgo) so $c will be three. And when I start $i at zero and go up to 2, I will be checking the variables $wspgo[0], $wspgo[1], and $wspgo[2] which of course don't exist.

But if you use the foreach technique, then you end up with variables $k and $v (which is short for Key and Value). So the first time the foreach loop happens, $k is 1 and $v is 17. And you can do your if statements on $v. And then you finish the loop. The next time through, $k will be 4 and $v will be 7.

So barand was about three steps ahead of us - and he was doing it the right way - I just wanted you to be able to see the long hand version so that you could learn to write your own code.

balloontrader

etully wrote:
So barand was about three steps ahead of us - and he was doing it the right way - I just wanted you to be able to see the long hand version so that you could learn to write your own code.

That's why I'm here instead of just looking for "scripts".

I am a fairly quick study, but have really no programing training, and only a HS education.

Put me in a studio and I'm a wiz.... here I'm "The Sorcerer's Apprentice"

But I don't think I'm doing too shabby for a 47 yr old know-nothing.

I greatly appreciate the tutalage.

Now....

$wspmay=$wspd; 
$i=0; 
$c=count($wspd); 
while ($i < $c) { 
if ($wspmay[$i] <7)  { $wspmay[$i] = 0; } 
if ($wspmay[$i] >8)  { $wspmay[$i] = 0; } 
$i++; 
}

and SHOULD be written as follows

$wspmay=$wspd; 
$i=0; 
$c=count($wspd); 
while ($i < $c) { 
if ($wspmay[$i] <7 or $wspmay[$i] >8)  { $wspmay[$i] = 0; } 
$i++; 
}

Is this a space saver?... a time saver?... or just a different way of doing the same thing?

etully

It's a little bit of a time saver and a tiny little bit of a space saver. And yes, it's really just another way of doing the same thing. The reason you do it is because it's easier to read. It's about style. It's about smooth versus jerky.

etully

Let me give you an example of why it matters: Imagine that instead of this:

if ($wspmay[$i] <7) { $wspmay[$i] = 0; }
if ($wspmay[$i] >8) { $wspmay[$i] = 0; }

You really wanted to do this:

if ($wspmay[$i] <7) { 
Insert 75 lines of complex code here }
if ($wspmay[$i] >8) {
Insert the same 75 lines of code here }

Now you're doing the same 75 lines of code in either of the two conditions. So you've written 150 lines of code and 75 are just duplicates of the first 75. Here are the problems that can arise from that:

Someone is working on your code and makes a change to one set of 75 lines but doesn't notice that they need to make the same change in the other 75 lines.
Someone is working on a tight deadline and needs to understand your code fast. They read the first IF statement, and the 75 lines of code and they determine, "Ok, now I understand what is supposed to happen when the variable is less than 7. Now let me read the next 75 lines to see what happens when the variables is greater than 8." So they read and read. And then they look and look for differences and they don't find any. It slows them down - it's a waste of time.

Mainly, the little habits that you pick up now will stay with you so it's a good idea to learn to do it right in the beginning when, admittedly, it barely makes a difference.

barand

if ($wspmay[$i] <7) { $wspmay[$i] = 0; }
if ($wspmay[$i] >8) { $wspmay[$i] = 0; }

In the above code, both conditions are always evaluated, whereas in this code

if ( ($wspmay[$i] <7) || ($wspmay[$i] >8) ) { $wspmay[$i] = 0; }

if it is < 7 it can ignore the check for > 8 as the condition is satisfied anyway. The >8 bit is only evaluated if the first part is false.

So the second snippet will me slightly faster.