问题
I have a simple associative array.
$a = array("a"=>"b", "c"=>"d");
I want to check if the key "1" exists in the array, e.g.
isset($a["1"]);
This string is being treated as an integer, so that
echo $a["1"]; //prints "d"
How do I get it to treat it as a string?
I don't want to use array_key_exists or in_array because my benchmarking shows isset will be a lot faster.
回答1:
It doesn't appear that you can do what you want to do. from http://us.php.net/manual/en/language.types.array.php:
A key may be either an integer or a string. If a key is the standard representation of an integer, it will be interpreted as such (i.e. "8" will be interpreted as 8, while "08" will be interpreted as "08").
You'll probably have to use Fosco's suggestion of prefixing all your keys with something. If you use the same prefix on every key, then it doesn't matter if you're parsing a text that might have words and numbers - put the same prefix on everything regardless.
回答2:
isset($a["1"]) | isset($a[1]) ?
Or just isset($a[1])
Or even isset($a[intval(1)]) to be 1000% sure.
回答3:
if echo $a['1'] prints d, then your array has more elements than you realize.
see var_dump($a) and print_r($a) functions to help you debug your code.
来源：https://stackoverflow.com/questions/4637680/php-associative-arrays-how-to-treat-integer-as-string