Which function returns a substring given a starting position and a length?

Which function returns a substring given a starting position and a length?

• A. Mid
• B. Left
• C. Right
• D. Substring

Answer: (A)

Extracting a portion of a string by specifying a start position and a length is about slicing the string rather than taking characters from an end. The function that does this specifically is designed to return a substring starting at a given index and continuing for a defined number of characters. In Visual Basic and similar environments, this is the Mid function. It takes the string, the starting position, and the number of characters to return, and it gives you exactly that slice. For example, Mid("abcdef", 3, 2) yields "cd". Left and Right work from the ends of the string—Left grabs characters from the leftmost side, Right from the rightmost side—so they don’t match the requirement of starting somewhere in the middle with a specified length. Substring is a general term for extracting a portion from within a string, and in some languages there is a Substring function, but in this context the specific function that takes a starting position and a length is Mid.

Extracting a portion of a string by specifying a start position and a length is about slicing the string rather than taking characters from an end. The function that does this specifically is designed to return a substring starting at a given index and continuing for a defined number of characters. In Visual Basic and similar environments, this is the Mid function. It takes the string, the starting position, and the number of characters to return, and it gives you exactly that slice. For example, Mid("abcdef", 3, 2) yields "cd".

Left and Right work from the ends of the string—Left grabs characters from the leftmost side, Right from the rightmost side—so they don’t match the requirement of starting somewhere in the middle with a specified length. Substring is a general term for extracting a portion from within a string, and in some languages there is a Substring function, but in this context the specific function that takes a starting position and a length is Mid.