CODEWITHSUNDEEP
phparraysloopsfor-loop
coder
coder

Reputation: 299

PHP: Delete all array elements before a specific one

Hi I've got the following array:

$days = array(
            1=>"Sunday",
            2=>"Monday",
            3=>"Tuesday",
            4=>"Wednesday",
            5=>"Thursday",
            6=>"Friday",
            7=>"Saturday"
            );

Now I want to make a loop that automatically removes all objects before number 4.
I tried this:

$startIndex = 4;
for($i = 1; $days < $startIndex; $i++)
{
    unset($days[$i]);
}

But it does not work.

Upvotes: 6

Views: 1924

Answers (3)

syck
syck

Reputation: 3029

A shorter solution may be given using array_slice():

$days = array(
            1=>"Sunday",
            2=>"Monday",
            3=>"Tuesday",
            4=>"Wednesday",
            5=>"Thursday",
            6=>"Friday",
            7=>"Saturday"
            );


$startIndex = 4;
$days = array_slice($days, $startIndex-1, NULL, TRUE);

print_r($days);

returns

Array
(
    [4] => Wednesday
    [5] => Thursday
    [6] => Friday
    [7] => Saturday
)

Upvotes: 7

Andr&#233; Ferraz
Andr&#233; Ferraz

Reputation: 1521

Your array

$days = array
(
     1=>"Sunday",
     2=>"Monday",
     3=>"Tuesday",
     4=>"Wednesday",
     5=>"Thursday",
     6=>"Friday",
     7=>"Saturday"
);

Loop to remove all element before a specified index.

# Number to stop the unset.
$split_number =4;
# Loop through array

for($a=0;$a<sizeof($days);$a++)
{
    if($a < $split_number)
        # Unset element if condition is true
        unset($days[$a]);
}

print_r($days);

Result

Array
(
    [4] => Wednesday
    [5] => Thursday
    [6] => Friday
    [7] => Saturday
)

If you wish the indexes to start from 0 again, you can use the array_values

Upvotes: 0

Marcin
Marcin

Reputation: 1494

Change $days to $i as $i is your index value.

$days = array(
            1=>"Sunday",
            2=>"Monday",
            3=>"Tuesday",
            4=>"Wednesday",
            5=>"Thursday",
            6=>"Friday",
            7=>"Saturday"
            );


$startIndex = 4;
for($i = 1; $i < $startIndex; $i++)
{
    unset($days[$i]);
}

print_r($days);

Upvotes: 3

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