Variable Insanity

[GiffordS]

Ok, once again I've managed to over-think a piece of code. I've gotten this to the point where nothing I try completely works. The problem is a simple one. I need to generate variables from a MySql query result. No biggie. However, I want to iterate the variable names. For example, let's say I have a database of cars. I then have a field in the db called "Make". Ok, now, when I run a query I want to pull down the Makes of cars, and use them as $car1, $car2, $car3 etc. The while loop is no problem, and I figure that I can increment the number by one each time by setting a variable, ($x) to one before the while loop, and at the end of each loop increase $x by one. No problem. The issue is in the syntax of naming the variable. I can't, for example, use

$car$x = $row["Make"]

I've tried

$$car$x = $row["Make"]

but that's not right either. I want to be able to access this variable later by calling the value of $car1, or $car6, etc. Does anyone know the correct syntax for instantiating that variable?

 

[skiflyer]

Geeze, no.

I'm going to make a strong suggestion that you use arrays instead though... much simpler, and PHP has some support which makes them even easier to use than most other languages.

so have
$cars[] = $row["Make"], then later you can do

foreach ($cars as $car) {
echo $car;
}

or

echo $cars[2];

or if you think it'll be useful to know the index of each, use a counter and explicitly state

$cars[$x] = $row["Make"];

where $x is whatever changing value you like, integers, words, phrases, whatever floats your boat.


-Rob

 

[sleipnir214]

I recommend that you put the values in an array:

$car = array();
$car[] = $row["Make"];

It makes it a lot easier to reference the values. Your way will require a lot of jumping through hoops to loop through $car1, $car2, etc. With an array, it's just $car[1].
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[GiffordS]

I considered this, but I guess I didn't give enough information. First of all, "Make" is just one of the variables. But it would be the primary one, so that I may also have Year, Color, etc. Ideally, I would have $car1, $car1yr, $car1cl, etc. The other issue with the array, where I thought it would be easier to define all of the variables up front, is that the values will be echoed at different times in the display. I may want to display $car3, $car3yr, $car3cl, etc., and then further on down call the next, or previous, car. I'm sure that you guys are probably still right and for whatever reason I just can't see it. It's one of those things where I just need to stop looking at it for an hour and it will all make sense and then I'll feel like a total yabohead.

 

[sleipnir214]

Sounds to me like you should use a multi-dimensional array.

Let's say that your database query returns columns named "Make", "Model", "Year", and "Color" in each loop through the retrieval.

Then:

$cars = array();
while ($row = mysql_fetch_assoc ($resource))
{
$cars[] = $row;
}

will put all the values in the array.

Then you can retrieve them as:

$cars[1]["Make"] will get the make of car 1.
$cars[2]["Model"] will get the model of car 2.
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[GiffordS]

I'm not saying you're wrong. In fact, I will say that as I just read through my original question, if I were reading that post I would suggest a multi-dimensional array as well. What will eventually happen here is that I will either use the array or change the way I deal with the query in the first place. But, just so I can stop my brain from churning on this, what would be the proper syntax for increment variable names as I mentioned? It drives me nuts to have something like that and not know the answer.

 

[sleipnir214]

It'll be somewhere in

http://www.php.net/manual/en/language.variables.variable.php

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[wuz]

I'm not sure if this is what you're looking for, and I'm no expert, so this might not be the perfect solution. But I would use this: ${"car$x"} to refer to $car1, $car2, $car3, etc. in a loop where you increment by $x.

Hope that helps!
Susan