I have used PHP for a long time, but I just saw something like,
${ }
To be precise, I saw this in a PHP Mongo page:
$m = new Mongo("mongodb://${username}:${password}@host");
So, what does ${ }
do? It is quite hard to search with Google or in the PHP documentation for characters like $
, {
and }
.
This operator allows for simpler three-way comparison between left-hand and right-hand operands. The operator results in an integer expression of: 0 when both operands are equal. Less than 0 when the left-hand operand is less than the right-hand operand.
passing argument through reference (&$) and by $ is that when you pass argument through reference you work on original variable, means if you change it inside your function it's going to be changed outside of it as well, if you pass argument as a copy, function creates copy instance of this variable, and work on this ...
Basic PHP Syntax A PHP script can be placed anywhere in the document. The default file extension for PHP files is " . php ". A PHP file normally contains HTML tags, and some PHP scripting code.
It means assign the key to $user and the variable to $pass. When you assign an array, you do it like this. $array = array("key" => "value"); It uses the same symbol for processing arrays in foreach statements. The '=>' links the key and the value.
${ }
(dollar sign curly bracket) is known as Simple syntax.
It provides a way to embed a variable, an array value, or an object property in a string with a minimum of effort.
If a dollar sign ($) is encountered, the parser will greedily take as many tokens as possible to form a valid variable name. Enclose the variable name in curly braces to explicitly specify the end of the name.
<?php $juice = "apple"; echo "He drank some $juice juice.".PHP_EOL; // Invalid. "s" is a valid character for a variable name, but the variable is $juice. echo "He drank some juice made of $juices."; // Valid. Explicitly specify the end of the variable name by enclosing it in braces: echo "He drank some juice made of ${juice}s."; ?>
The above example will output:
He drank some apple juice. He drank some juice made of . He drank some juice made of apples.
It's an embedded variable, so it knows where to stop looking for the end of the variable identifier.
${username}
in a string means $username
outside of a string. That way, it doesn't think $u
is the variable identifier.
It's useful in cases like the URL that you gave, because then it doesn't need a space after the identifier.
See the php.net section about it.
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