in-operator - w3toppers.com

How to use php array with sql IN operator? [duplicate]

Since you have plain integers, you can simply join them with commas: $sql = “SELECT * FROM table WHERE comp_id IN (” . implode(‘,’, $arr) . “)”; If working with with strings, particularly untrusted input: $sql = “SELECT * FROM table WHERE comp_id IN (‘” . implode(“‘,'”, array_map(‘mysql_real_escape_string’, $arr)) . “‘)”; Note this does not … Read more

Override Python’s ‘in’ operator?

MyClass.__contains__(self, item)

Why does javascript’s “in” operator return true when testing if 0 exists in an array that doesn’t contain 0?

It refers to the index or key, not the value. 0 and 1 are the valid indices for that array. There are also valid keys, including “length” and “toString”. Try 2 in x. That will be false (since JavaScript arrays are 0-indexed). See the MDN documentation.