PHP获取键值或最大值

Question

I'v got this array:

$by_date = array(
    "2018-10-05"=>54,
    "2018-10-07"=>20,
    "2018-10-08"=>31,
    "2018-10-12"=>52
    );

I want to get value by date, but if the date doesn't exist get the lowest date value

for example:

if the date is "2018-10-07" I'll get 20

and if the date is "2018-10-10" I'll get 31

that can go to bigger differences between the date and the last key in the array

For example, if the date is "2019-01-25" I'll get 52 because "2018-10-12" is the last key in the array.

Thanks for the help :)

Answer 1

You can do it with a simple if condition that uses isset() to check for your input as a key on the array. If the condition is met, you return the matched value, otherwise, use max() and array_keys() to return the value with the highest key.

$by_date = array(
    "2018-10-05"=>54,
    "2018-10-07"=>20,
    "2018-10-08"=>31,
    "2018-10-12"=>52
    );

$testVal = '2018-10-12'

if (isset($by_date[$testVal]))
    return $by_date[$testVal];
else 
    return $by_date[max(array_keys($by_date))];