using for loop to display elements from array

[webdeveloper123]

Hi,

I've got a for loop  which displays elements from an array. The array looks like this:

$table = array ( 
            0 => array ( 
                'fname' => 'Peter', 
                'lname' => 'Smith', 
                'age' => '37'
                ), 
            1 => array ( 
                'fname' => 'Paul', 
                'lname' => 'Hartley', 
                'age' => '48'
                ), 
            2 => array ( 
                'fname' => 'Mary', 
                'lname' => 'Baker', 
                'age' => '42'
                ), 
            3 => array ( 
                'fname' => 'Jane', 
                'lname' => 'Doe', 
                'age' => '51'
              
                )
            );

The for loop looks like this:

for ($row = 0; $row < 4; $row++) {
  echo "<p><b>Row number $row</b></p>";
  echo "<ul>";
  for ($col = 0; $col < 1; $col++) {
    echo "<li>".$table[$row]['fname']."</li>";
     echo "<li>".$table[$row]['lname']."</li>";
      echo "<li>".$table[$row]['age']."</li>";
  }
  echo "</ul>";
}

Now this code is working fine. Then I set about adding an element to the array using array_push like this:

$newdata =  array (
      'fname' => 'Lionel',
      'lname' => 'Messi',
      'age' => '36'
    );



array_push($table,$newdata);

And I displayed it (sucessfully) using this:

for ($row = 0; $row < 5; $row++) {
  echo "<p><b>Row number $row</b></p>";
  echo "<ul>";
  for ($col = 0; $col < 1; $col++) {
    echo "<li>".$table[$row]['fname']."</li>";
     echo "<li>".$table[$row]['lname']."</li>";
      echo "<li>".$table[$row]['age']."</li>";
  }
  echo "</ul>";
}

Note: The only difference between the above 2 for loops is I changed $row < 4 to $row < 5

Then I wanted to add more than one element to the array so I used this:

$newdata = array ( 
            4 => array ( 
                'fname' => 'Jon', 
                'lname' => 'Atkins', 
                'age' => '27'
                ), 
            5 => array ( 
                'fname' => 'Phil', 
                'lname' => 'Jones', 
                'age' => '14'
                ), 
            6 => array ( 
                'fname' => 'Frank', 
                'lname' => 'Lampard', 
                'age' => '48'
                ), 
            7 => array ( 
                'fname' => 'Toney', 
                'lname' => 'Brentford', 
                'age' => '25'
              
                )
            );

array_push($table,$newdata);

But the weird baffling part is I am using the same forloop:

for ($row = 0; $row < 8; $row++) {
  echo "<p><b>Row number $row</b></p>";
  echo "<ul>";
  for ($col = 0; $col < 1; $col++) {
    echo "<li>".$table[$row]['fname']."</li>";
     echo "<li>".$table[$row]['lname']."</li>";
      echo "<li>".$table[$row]['age']."</li>";
  }
  echo "</ul>";
}

Note : This time I have changed $row < 8 but I get this error :

Row number 4


Notice: Undefined index: fname
 Undefined index: lname
Undefined index: age 

And errors like :

Row number 5


Notice: Undefined offset: 5 in on line 86

Notice: Trying to access array offset on value of type null in  on line 86

Notice: Undefined offset: 5 in  on line 87

Notice: Trying to access array offset on value of type null in  on line 87

Notice: Undefined offset: 5 in  on line 88

Notice: Trying to access array offset on value of type null in  on line 88

And I get the same errors as above for row 5 but for rows 6 and 7.

Btw, I have row numbers for each element in the array. So Row Number 0 displays the First Name, last name and age for the element at index 0 etc.

And I have done a print_r($table) and get this:

Array ( [0] => Array ( [fname] => Peter [lname] => Smith [age] => 37 ) [1] => Array ( [fname] => Paul [lname] => Hartley [age] => 48 ) [2] => Array ( [fname] => Mary [lname] => Baker [age] => 42 ) [3] => Array ( [fname] => Jane [lname] => Doe [age] => 51 ) [4] => Array ( [4] => Array ( [fname] => Jon [lname] => Atkins [age] => 27 ) [5] => Array ( [fname] => Phil [lname] => Jones [age] => 14 ) [6] => Array ( [fname] => Frank [lname] => Lampard [age] => 48 ) [7] => Array ( [fname] => Toney [lname] => Brentford [age] => 25 ) ) )

It seems there are two [4] in the array. I would ideally like to get the rows automatically adjusted so I don't have to keep changing the code when I add new elements in the array. I used 

$arrayLength = count($table);

And changed it to: (only showing relevant code here, the rest is same as above for loops):

$row < $arrayLength;

and I get these errors:

Notice: Undefined index: fname  on line 86

Notice: Undefined index: lname   on line 87

Notice: Undefined index: age  on line 88

But the offset errors disappear 

Sorry for long post

Many thanks

[Barand]

Use foreach() to iterate through arrays.

foreach ($table as $row => $data) {
  echo "<p><b>Row number $row</b></p>";
  echo "<ul>";
  foreach ($data as $col) {
    echo "<li>$col</li>";
  }
  echo "</ul>";
}

 

[webdeveloper123]

Hey Barand, yes I used foreach before on this array sucessfully but then came across this for loop and thought it look interesting and so I gave it a try.

I'm Using:

foreach ($table as $row => $data) {
  echo "<p><b>Row number $row</b></p>";
  echo "<ul>";
  foreach ($data as $col) {
    echo "<li>$col[fname]</li>";
    echo "<li>$col[lname]</li>";
    echo "<li>$col[age]</li>";
  }
  echo "</ul>";
}

and I am getting the data from $newdata but getting illegal offset errors all over the page for the other array. Plus the data from $newdata shows all records under Row Number 4 but apparently they should all be in 1 array now ($table)

[webdeveloper123]

sorry that should read:

and I am getting the data from $newdata but getting illegal offset errors all over the page for the other array. even though  apparently they should all be in 1 array now ($table). Plus the data from $newdata shows all records under Row Number 4

[Barand]

How many arrays do you now have?

$table = array ( 
            0 => array ( 
                'fname' => 'Peter', 
                'lname' => 'Smith', 
                'age' => '37'
                ), 
            1 => array ( 
                'fname' => 'Paul', 
                'lname' => 'Hartley', 
                'age' => '48'
                ), 
            2 => array ( 
                'fname' => 'Mary', 
                'lname' => 'Baker', 
                'age' => '42'
                ), 
            3 => array ( 
                'fname' => 'Jane', 
                'lname' => 'Doe', 
                'age' => '51'
              
                )
            );
            
$newdata = array ( 
            4 => array ( 
                'fname' => 'Jon', 
                'lname' => 'Atkins', 
                'age' => '27'
                ), 
            5 => array ( 
                'fname' => 'Phil', 
                'lname' => 'Jones', 
                'age' => '14'
                ), 
            6 => array ( 
                'fname' => 'Frank', 
                'lname' => 'Lampard', 
                'age' => '48'
                ), 
            7 => array ( 
                'fname' => 'Toney', 
                'lname' => 'Brentford', 
                'age' => '25'
              
                )
            );
            
$table = array_merge($table, $newdata);

foreach ($table as $row => $data) {
  echo "<p><b>Row number $row</b></p>";
  echo "<ul>";
  foreach ($data as $col) {
    echo "<li>$col</li>";
  }
  echo "</ul>";
}

giving

[webdeveloper123]

oh no!! I was thinking maybe it should be array_merge a few hours ago but thought Nah it can't be! anyway, thanks for the code barand!

[webdeveloper123]

So it must have done it first time when I inserted one new element into the array, but because I Had more than one element I had to use array_merge?

[webdeveloper123]

btw, I just used array_merge on the for loop script and it works!

[andrejuniordesouza]

try like this:

Edited May 3, 2022 by andrejuniordesouza

[Barand]

There is always more than one way to solve a problem. Instead of array_merge() you could

add them individually, using array_push() as above or

$table[] =  array ( 
                'fname' => 'Jon', 
                'lname' => 'Atkins', 
                'age' => '27'
                );
                 
$table[] =  array ( 
                'fname' => 'Phil', 
                'lname' => 'Jones', 
                'age' => '14'
                ); 
                
$table[] = array ( 
                'fname' => 'Frank', 
                'lname' => 'Lampard', 
                'age' => '48'
                );
                 
$table[] = array ( 
                'fname' => 'Toney', 
                'lname' => 'Brentford', 
                'age' => '25'
                );

or you could loop through the newdata array to add them to $table

foreach ($newdata as $rec) {
    $table[] = $rec;
}

 

[webdeveloper123]

thanks Barand and andrejuniordesouza!