Why are there periods in PHP? [duplicate]

This question already has answers here: Close开发者_JAVA技巧d 11 years ago.

Possible Duplicate:

What does the 'period' character (.) mean if used in the middle of a php string?

Why are the periods included in the code that follows?

require("mod/" . $modarrayout . "/bar.php");

Obviously, it's because the variable is between strings, but shouldn't the quotes have taken care of that? PHP

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In PHP, the period is the concatenation operator. Putting the periods in tells PHP to concatenate "mod/" to $modarrayout and then concatenate the resulting string to "/bar.php". See page String Operators.

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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.

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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: String Operators