The Substring function extracts a portion of the parameter based on the specified character placement.
Parameter: string
The string to extract from. This can come from a source node, the result of another function, or a value you specify.
Parameter: number1
The position of the first character to extract. Characters are numbered in the string beginning from 1.
Parameter: [number2]
The total number of characters to extract. If you omit this parameter, it defaults to the length from the starting position to the end of the first parameter.
Returns: string
The substring for the specified character places.