substr
(substr string start [length])
The substr function returns a new (partial) string based on a given string argument starting at start.
Arguments
The string argument specifies the original text string to retrieve a sub-string from.
The start argument indicates which character in the string to start from. The starting number of the first character is 1.
The optional length argument specifies the number of characters to include in the sub-string.
Return Value
The function returns a sub-string.
: (substr "1234567890" 3 6)
"345678"
: (substr "1234567890" 3)
"34567890"