Question

Can an array key in PHP be a string with embedded zero-bytes?

I wanted to implode a multi-part key with embedded zero-bytes as the delimiter and use it as the key in an associative array, but it doesn’t seem to be working. Not sure whether this is a problem with the array access or with array_keys_exists().

Does anybody have any idea? Am I going about this the wrong way? Should I be creating a multi-part key in another way?

To clarify, I am trying to eliminated duplicates from user-entered data. The data consists of a product ID, a variation ID, and N fields of textual data. Each of the N fields has a label and a value. To be considered a duplicate, everything must match exactly (product ID, variation ID, all the labels and all the values).

I thought that if a create a string key by concatenating the information with null bytes, I could keep an associative array to check for the presence of duplicates.

Answer 1

From the PHP string documentation:

There are no limitations on the values the string can be composed of;
in particular, bytes with value 0 (“NUL bytes”) are allowed anywhere
in the string (however, a few functions, said in this manual not to be
“binary safe”, may hand off the strings to libraries that ignore data
after a NUL byte.)

From the PHP arrays documentation:

A key may be either an integer or a string.

No mention is made of any special case for strings that are array keys.

So, yes.