Array with Keys only

[SaranacLake]

Is it possible to create a PHP array that contains only keys?

	array
	1
	3
	5
	6
	7
	

 

I have a query that returns row ID's that I want to put into an array to do some work.  There is no real concept of a "value" - I just need to store a list of the database table rows that i want and that's it!

 

Edited February 16, 2021 by SaranacLake

[SaranacLake]

Not getting anywhere today... ;-(

I have a query in my script using prepared statements.

The query returns a listing of required questions.

	if (mysqli_stmt_num_rows($stmt10)>0){
    mysqli_stmt_bind_result($stmt10, $requiredItem);
    mysqli_stmt_fetch($stmt10);
    while (mysqli_stmt_fetch($stmt10)){
        $requiredItemsArray[$requiredItem] = 'xxx';
    }
	

 

When I copy and paste my query into phpMyAdmin, it gives met {1,3,5,6,7}

When I run the above PHP code, my var_dump($requiredItemsArray), then I get {3=>'xxx', 5=>'xxx', 6=>'xxx', 7=>'xxx'}

Where is 1?

 

1.) Ideally, I want an array that just lists {1,3,5,6,7} like my query.

 

2.) I would like to figure out why I am missing "1"?!

 

Thanks.

 

[requinix]

No, you cannot have an array of just keys, because the very nature of a key is that it provides the location to a value.
You also cannot have an array with just values, because no keys would mean you wouldn't know where a value was in the array.

 

53 minutes ago, SaranacLake said:

Where is 1?

It was returned by that first useless call to mysqli_stmt_fetch.

[SaranacLake]

7 hours ago, requinix said:

No, you cannot have an array of just keys, because the very nature of a key is that it provides the location to a value.
You also cannot have an array with just values, because no keys would mean you wouldn't know where a value was in the array.

 

It was returned by that first useless call to mysqli_stmt_fetch.

Insulting me and my code does nothing to help me understand why the above code is not working.

I have used similar code all along, so I'm not sure what is wrong - although the answer is probably right in front of me.

	mysqli_stmt_fetch($stmt10);
	

should return all of the applicable rows from my query - which works fine in phpMyAdmin.

 

And

	while (mysqli_stmt_fetch($stmt10)){         
	    $requiredItemsArray[$requiredItem] = 'xxx';   
	 }
	

should populate my array with (1, 3, 5, 6, 7) as the keys and 'xxx' as junk values since all I need are the keys.

 

So what am I doing wrong?

 

 

[requinix]

6 minutes ago, SaranacLake said:

Insulting me and my code does nothing to help me understand why the above code is not working.

I was insulting you?

 

Quote

I have used similar code all along, so I'm not sure what is wrong - although the answer is probably right in front of me.

It is.

 

Quote

 

	mysqli_stmt_fetch($stmt10);
	

should return all of the applicable rows from my query - which works fine in phpMyAdmin.

No. What that does is fetch the next row in the resultset, which then updates $requiredItem.

 

Quote

And

	while (mysqli_stmt_fetch($stmt10)){         
	    $requiredItemsArray[$requiredItem] = 'xxx';   
	 }
	

should populate my array with (1, 3, 5, 6, 7) as the keys and 'xxx' as junk values since all I need are the keys.

It's populating the array with the remaining rows from the resultset.

 

Okay, let's say you don't know what mysqli_stmt_fetch does.

In your while loop, you call the function: if it returns good then you put $requiredItem into the array, and if it returns bad then you stop. Clearly mysqli_stmt_fetch does something that moves you row by row through the resultset, right?
Now look at the code before the loop. You call mysqli_stmt_fetch. We now know that moves through a single row. However, where your while loop did something with $requiredItem after every call to mysqli_stmt_fetch, before the loop you do not.

Think about that.

[SaranacLake]

I just grabbed another block of code that did a similar thing, pasted it into BBEdit, stripped out all of the specifics, and looked at my working code structure.

At the very end, I see that my working code has...

	while(mysqli_stmt_fetch($stmt2)){
	

 

Then I noticed that I have an EXTRA...

]code]

mysqli_stmt_fetch($stmt10)

[/code]

in my broken code.

 

NOW I see what Iw as doing wrong!

(I haven't been outside in like 3 1/2 days - so that is the real problem.

We had an ice storm, but I need to try and go to the store or something and clear my brain...