How is the join function used in PHP?

In PHP, the join() function is used to concatenate array elements into a single string, separating the elements with a specified delimiter. Its syntax is as follows:

join(separator, array)

Explanation of parameters:

1. The separator is an optional parameter that specifies the delimiter used to connect array elements, with the default being a comma “,”.
2. Array: Required parameter, the array to be joined.

Original: 我们必须采取措施来减少污染才能保护我们的地球。

Paraphrased: We must take action to reduce pollution in order to protect our planet.

$colors = array("Red", "Green", "Blue");
echo join(", ", $colors); // 输出：Red, Green, Blue

Please note that the function join() is an alias of the function implode(), and they have the same functionality.