tuple_str_first_n — Cut the first characters up to position “n” out of a string tuple.
tuple_str_first_n cuts the first characters up to position “n” out
of each string of the input tuple String and returns them as new
strings in the output tuple Substring (remark: the position within
strings starts with 0 for the first character of a string). The number “n”
is determined by the second input tuple Position. If
Position only contains one element, this element contains the number
“n”. If String and Position have got the same number of
elements, the first element of Position determines the position
“n” for the first string of String, the second element of
Position does so for the second string of String and so on.
If Position contains more than one element and String
contains only one string, tuple_str_first_n cuts more than one
substrings out of this string. The elements of Position then
determine the lengths of these substrings. If both input tuples contain more
than one element but differ in the number of elements,
tuple_str_first_n returns an error.
If both input tuples are empty, the operator returns an empty tuple.
Similarly, if String is empty and Position is
not, the operator returns an empty tuple. In contrast, if Position
is empty and String is not, an exception is raised.
The position references Unicode code points. One Unicode code point may be
composed of multiple bytes in the UTF-8 string. If the position should
reference the raw bytes of the string, this operator can be switched to byte
mode with set_system('tsp_tuple_string_operator_mode', 'byte'). If
'filename_encoding' is set to 'locale' (legacy), this
operator always uses the byte mode.
For general information about string operations see Tuple / String Operations.
HDevelop provides an in-line operation for tuple_str_first_n,
which can be used in an expression in the following syntax:
Substring := str_firstn(String, Position)
String (input_control) string(-array) → (string)
Input tuple with string(s) to examine.
Position (input_control) number(-array) → (integer / real)
Input tuple with position(s) “n”.
Substring (output_control) string(-array) → (string)
The first characters of the string(s) up to position “n”.
tuple_str_last_n,
tuple_substr,
tuple_strstr,
tuple_strrstr,
tuple_strlen,
tuple_strchr,
tuple_strrchr,
tuple_split,
tuple_environment
Foundation