PHP 函数与 SPSS 函数比较

<?php
$data = [1, 2, 3, 4, 5];
$first_element = array_shift($data);
$last_element = array_pop($data);
echo "First element: $first_element, Last element: $last_element";
?>

* Modify cases data file cases.sav. Remove first and the last cases.
DATA LIST LIST (id age) FREE.
BEGIN DATA
1 20
2 21
3 22
4 23
5 24
END DATA.
EXECUTE.

* Extract first and second cases in an output data file first_second.sav
GET FILE=cases.sav.
RECODE id (1=first) (2=second) INTO codes.
EXECUTE.
SELECT IF (codes=1 OR codes=2).
EXECUTE.
SAVE OUTFILE='first_second.sav'.

<?php
$data = [1, 2, 3, 4, 5];
$avg = array_sum($data) / count($data);
echo "Average: $avg";
?>

* Calculate the mean value of the age variable in cases.sav.
DATA LIST LIST (id age) FREE.
BEGIN DATA
1 20
2 21
3 22
4 23
5 24
END DATA.
EXECUTE.

COMPUTE avg_age = MEAN (age).
EXECUTE.

* Show the data for the variable avg_age.
LIST VARIABLES=avg_age.

<?php
$timestamp = mktime(10,30,0,6,1,2023);
$formatted_date = date("d/m/Y H:i:s", $timestamp);
echo "Formatted date: $formatted_date";
?>

* Recode date variable in cases.sav to mm/dd/yyyy format.
DATA LIST LIST (id dateString) DATE('ddmmyyyy').
BEGIN DATA
1 20230601
2 20230602
3 20230603
4 20230604
5 20230605
END DATA.
EXECUTE.

RECODE dateString (20230601='06/01/2023') (20230602='06/02/2023')
               (20230603='06/03/2023') (20230604='06/04/2023')
               (20230605='06/05/2023') INTO newDate.
EXECUTE.