PHP array_shift() not working for me. What am I doing wrong?

Question

I am creating an array and want to delete the first element of the array and re-index it. From what I can tell, array_shift() is the right solution. However, it is not working in my implementation.

I have a member variable of my class that is defined as an array called $waypoint_city. Here is the variable output prior to shifting the array:

print_r($this->waypoint_city);

Result:

Array ( [0] => [1] => JACKSONVILLE [2] => ORLANDO [3] => MONTGOMERY [4] => MEMPHIS )

If I do the following, I get the correct result:

print_r(array_shift($this->waypoint_city));

Result:

Array ( [0] => JACKSONVILLE [1] => ORLANDO [2] => MONTGOMERY [3] => MEMPHIS )

However, if I try to reassign the result to the member variable it doesn't work... Anyone know why that is?

$this->waypoint_city = array_shift($this->waypoint_city);

If I try to print_r($this->waypoint_city) it looks like nothing is in there. Thanks to anyone who can save the hair that I haven't pulled out, yet.

Felix Kling · Accepted Answer · 2011-06-30 22:47:34Z

11

array_shift^[docs] changes the array in-place. It returns the first element (which is empty in your case):

Returns the shifted value, or NULL if array is empty or is not an array.

All you have to do is:

array_shift($this->waypoint_city);

answered Jun 30, 2011 at 22:47

Felix Kling

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1 Comment

user77413 Over a year ago

This is a classic case of RTFM... I feel like an idiot. Thanks for setting me straight. Thanks!!!

Chris Eberle · Accepted Answer · 2011-06-30 22:48:41Z

2

That's because there IS nothing there. You have element 0 set to nothing, and array_shift returns the shifted element, which the first time through is null.

answered Jun 30, 2011 at 22:48

Chris Eberle

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Comments

Emre Yazici · Accepted Answer · 2011-06-30 22:48:46Z

1

array_shift() gets its parameter as reference, so you should call array_shift() like this:

$shiftedElement = array_shift(&$this->waypoint_city);

answered Jun 30, 2011 at 22:48

Emre Yazici

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