问题
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What does the 'period' character (.) mean if used in the middle of a php string?
as the title says, why are the periods? such as
require("mod/".$modarrayout."/bar.php");
obviously its because the variable is between strings, but shouldnt the quotes have taken care of that? Just want to know to clarify further coding
回答1:
In PHP, the period is the concatentation operator. Putting the periods in tells PHP to concatenate "mod/" to $modarrayout and then concatenate the resulting string to "/bar.php". See this page:
http://www.php.net/manual/en/language.operators.string.php
回答2:
The following is the same in this case:
require("mod/$modarrayout/bar.php");
Using string concatenation is a different approach to string building.
I suggest reading the manual page on strings.
回答3:
There are two string operators. The first is the concatenation operator ('.'), which returns the concatenation of its right and left arguments. The second is the concatenating assignment operator ('.='), which appends the argument on the right side to the argument on the left side.
read: http://php.net/manual/en/language.operators.string.php
来源：https://stackoverflow.com/questions/6159172/why-are-there-periods-in-php