asked on

How can I get these two for loops to talk to one another politely?

Here's the first piece of this puzzle:

$selectTerms=$conn->prepare("SELECT * FROM test_date");
		$selectTerms->execute();
		$selectTermsCount=$selectTerms->rowCount();

		$selectTermsRow=$selectTerms->fetchAll(PDO::FETCH_ASSOC);

		foreach($selectTermsRow as $column)
		{
			$column_name=array_keys($column);
		}

               foreach($column_name as $name)
		{
		 echo $name.'&nbsp;';
		}

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When I do that, I get "id column_name column_data."

Perfect.

When I run this for loop:

for($i=1; $i<=$selectTermsCount-1; $i++)
			{
				echo $selectTermsRow[$i]['column_name'].'<br>';
			}

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I get this:

screeningperiodid
screeningtime
bfull

...and just so you can visualize the table this is coming from, here's a screen shot:

I want to combine these two loops in a way where I would get this:

id: 1
column_name: screeningsubperiodid
column_date: screeningsubperiod_data

In other words, I get the column name followed by the value.

How?

Ray Paseur

I'm not sure I completely understand the objective, so let's work through this a little bit. From the code snippet after the SELECT query, please do this and post the output in the code snippet here.

$selectTermsRow=$selectTerms->fetchAll(PDO::FETCH_ASSOC);
var_export($selectTermsRow);

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ASKER CERTIFIED SOLUTION

Julian Hansen

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SOLUTION

Ray Paseur

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Bruce Gust

ASKER

Ray, here's the var_export:

array ( 0 => array ( 'id' => '1', 'column_name' => 'screeningsubperiod', 'column_data' => 'screeningsubperiod_data', ), 1 => array ( 'id' => '2', 'column_name' => 'screeningperiodid', 'column_data' => 'screeningperiodid_data', ), 2 => array ( 'id' => '3', 'column_name' => 'screeningtime', 'column_data' => 'screeningtime_data', ), 3 => array ( 'id' => '4', 'column_name' => 'bfull', 'column_data' => 'bfull_data', ), )

Julian, your solution works. Why? What does "=>" do? How does that syntax parse out the column headings and line things up the way I was hoping?

I had tried various loops within loops and I was getting "id" and then all four rows worth of info and then "column_name" and then all four rows worth of info. It was a mess.

How does your code make the magic happen?

Julian Hansen

Given a return of

array (
array(
  "id" => 1, 
  "column_name" => "screeningsubperiodid",
  "column_date" => "screeningsubperiod_data"
  ),
array(
  "id" => 2, 
  "column_name" => "screeningid",
  "column_date" => "screening_data"
  ),
...
)

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The subarrays represent the rows retrieved from the fetch_all. They are associative so they have the column names as the keys.
The following code

foreach($row as $column=> $value) {
  echo "{$column} : $value<br/>";
}

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Makes use of the foreach option to include the key of the array in the loop - like this

foreach($array as $key => $value)

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You wanted to have each row dump as

Column Name: value

Given each field in the row has the column name as the key we can just pull that out in the loop and use it

Ray Paseur

All of the PHP functions are documented in the online man pages, so when you see something unfamiliar, the best first step is to look it up.

Example: PDOStatement::fetchAll(PDO::FETCH_ASSOC) tells us that it returns an array containing all of the result set rows. Given the PDO::FETCH_ASSOC flags, the method will make each of the rows into an associative array. Thus you have a return value from the method that is a numerically indexed array of arrays, with each of the inner arrays representing one row of the results set, like this.

array 
( 0 => array 
       ( 'id' => '1'
       , 'column_name' => 'screeningsubperiod'
       , 'column_data' => 'screeningsubperiod_data'
       )
, 1 => array 
       ( 'id' => '2'
       , 'column_name' => 'screeningperiodid'
       , 'column_data' => 'screeningperiodid_data'
       )
, 2 => array 
       ( 'id' => '3'
       , 'column_name' => 'screeningtime'
       , 'column_data' => 'screeningtime_data'
       )
, 3 => array 
       ( 'id' => '4'
       , 'column_name' => 'bfull'
       , 'column_data' => 'bfull_data'
       )
)

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What does "=>" do?

This is an assignment operator used in the context of array keys and values. It's just syntax.