Description:
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http://uk2.php.net/manual/de/language.types.array.php

There's no explanation in the online documentation of what value is returned when you access an array with a key/index that doesn't exist. 

For example, on line 3, I cannot use the documentation to tell me what $a["testing_invalid_index"] will return to me. Does it return 0 or "" or null or false, or does it give an error?

1) $a[] = array();
2) $a["sdfads"] = "booger";
3) if ($a["testing_invalid_index"] == false){
4)  echo "Something";
5) }

Reproduce code:
---------------
---
From manual page: language.types.array
---


Expected result:
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Documentation should indicate how an expression containing an array with an invalid key/index is evaluated.

Actual result:
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Documentation is missing information on how an expression containing an array with an invalid key/index is evaluated.