'AND' vs '&&' as operator
I have a codebase where developers decided to use AND and OR instead of && and || .
I know that there is a difference in operators' precedence ( && goes before and ), but with the given framework (PrestaShop to be precise) it is clearly not a reason.
Which version are you using? Is and more readable than && ? Or is there no difference?
If you use AND and OR , you'll eventually get tripped up by something like this:
$this = true;
$that = false;
$truthiness = $this and $that;
Want to guess what $truthiness equals?
If you said false ... bzzzt, sorry, wrong!
$truthiness above has the value true . Why? = has a higher precedence than and . The addition of parentheses to show the implicit order makes this clearer:
($truthiness = $this) and $that
If you used && instead of and in the first code example, it would work as expected and be false .
As discussed in the comments below, this also works to get the correct value, as parentheses have higher precedence than = :
$truthiness = ($this and $that)
Depending on how it's being used, it might be necessary and even handy. http://php.net/manual/en/language.operators.logical.php
// "||" has a greater precedence than "or"
// The result of the expression (false || true) is assigned to $e
// Acts like: ($e = (false || true))
$e = false || true;
// The constant false is assigned to $f and then true is ignored
// Acts like: (($f = false) or true)
$f = false or true;
But in most cases it seems like more of a developer taste thing, like every occurrence of this that I've seen in CodeIgniter framework like @Sarfraz has mentioned.
由于and优先级低于=您可以在条件分配中使用它：
if ($var = true && false) // Compare true with false and assign to $var
if ($var = true and false) // Assign true to $var and compare $var to false
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