is it safe to use a email id as a key for array in php

Question

I am trying to do the below in php

array(
  '[email protected]' => 'something',
  ...
);

I did read that php accepts and number or valid string as key.

is it safe to have email id as key in the array as above ? by safe I mean is possible that this could cause any kind of error or exception or problem when coding wit this

Note: I would be having several 100 items in this array is there something that I need to take care while I do this

Please let me know

Answer 1

Short answer: If it can be a string in PHP, nowadays, it can safely be used as an associate array key.

Long answer: From the PHP manual:

The key can either be an integer or a string. The value can be of any type.

Additionally the following key casts will occur:

Strings containing valid integers will be cast to the integer type. E.g. the key "8" will actually be stored under 8. On the other hand "08" will not be cast, as it isn't a valid decimal integer.

Floats are also cast to integers, which means that the fractional part will be truncated. E.g. the key 8.7 will actually be stored under 8. Bools are cast to integers, too, i.e. the key true will actually be stored under 1 and the key false under 0.

Null will be cast to the empty string, i.e. the key null will actually be stored under "".

Arrays and objects can not be used as keys. Doing so will result in a warning: Illegal offset type.

If multiple elements in the array declaration use the same key, only the last one will be used as all others are overwritten.