XQuery String-join()

In XQuery, the fn:string-join() function is used to concatenate a sequence of strings into a single string using a specified separator. This function takes two arguments: the sequence of strings to be joined and the separator string. It returns a single string that is the result of concatenating the input strings with the separator in between each pair of adjacent strings.

Here’s the syntax of the fn:string-join() function:

fn:string-join($sequence, $separator)

• $sequence: The sequence of strings to be joined together.
• $separator: The separator string used between each pair of adjacent strings.

Here’s an example of using fn:string-join() in XQuery:

let $fruits := ("apple", "banana", "orange", "grape")
let $result := fn:string-join($fruits, ", ")
return $result

Output:

"apple, banana, orange, grape"

In this example, we have a sequence of strings representing different fruits stored in the variable $fruits. We use the fn:string-join($fruits, ", ") function to join these strings together with a comma and space (“, “) as the separator, and the result is stored in the variable $result.

If the input sequence is empty or contains only one item, the fn:string-join() function will return that item without applying the separator.

Keep in mind that the fn:string-join() function works with sequences of strings, and if you have a sequence of non-string values, you may need to convert them to strings before using this function. For example, you can use the string() function to convert non-string values to strings if needed.

let $numbers := (1, 2, 3, 4, 5)
let $result := fn:string-join($numbers ! string(), ", ")
return $result

Output:

"1, 2, 3, 4, 5"

In this example, we used the ! operator (sequence constructor) to apply the string() function to each item in the $numbers sequence before joining them with the separator.