Check First 2 Digits Of All Values in an Array

Question

I have an array_filter callback function that checks if digits are in an array like so:

$code = "22";
$orders = array_filter(
            $orders,
            function ($key) use($code) {
                return (in_array($code, $key['trans']));
            }
        );

But this is checking if the trans value has a digit that matches exactly 22, so it's limiting the results.

I'd like to display all trans value's that start with the $code (22) - I'd like to ignore using a for loop if possible, since it'll take longer to display the results.

What can I do instead?

Just to be clear, you want to filter out all elements that don't start with `22`? — waterloomatt, Sep 18 '20 at 18:50
Just an FYI - for (each) loops are generally faster than their array_* equivalents. http://www.levijackson.net/are-array_-functions-faster-than-loops/ — waterloomatt, Sep 18 '20 at 18:55

Anton · Answer 1 · 2020-09-18T19:28:02.080

2

Try changing:

return (in_array($code, $key['trans']));

to

return substr( $key['trans'], 0, strlen($code) ) == $code;

If $key['trans'] is array, then we need to iterate it to search for $code inside it (sandbox example):

return count(array_filter($key['trans'],
  function ($key2) use($code) {
    return substr( $key2, 0, strlen($code) ) == $code;
  })) > 0;

P.S. I used array_filter for inner array because of this answers: find beginning of a string inside an array of strings in php

P.P.S. This is my one-line solution. As @waterloomatt mentioned in comments, simple for is faster than array_filter, so better to create a helper function to check if array has something inside that starts with what you need.

edited Sep 18 '20 at 19:28

answered Sep 18 '20 at 18:55

Anton

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Very nice solution. – waterloomatt Sep 18 '20 at 19:06
This would work if trans only had one value - sorry I should have specified this in my question. The trans has an array of values, so therefor substr() function wouldn't work here. – alexel Sep 18 '20 at 19:10
@alexel My bad. Updated my answer. Now better? – Anton Sep 18 '20 at 19:21

Check First 2 Digits Of All Values in an Array

1 Answers1