Operator Reference

HALCON Operator Reference / Tuple / String Operations

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tuple_str_first_ntuple_str_first_nTupleStrFirstNTupleStrFirstNtuple_str_first_n (Operator)

tuple_str_first_ntuple_str_first_nTupleStrFirstNTupleStrFirstNtuple_str_first_n — Cut the first characters up to position “n” out of a string tuple.

Signature

tuple_str_first_n( : : String, Position : Substring)

Herror tuple_str_first_n(const char* String, const Hlong Position, char* Substring)

Herror T_tuple_str_first_n(const Htuple String, const Htuple Position, Htuple* Substring)

void TupleStrFirstN(const HTuple& String, const HTuple& Position, HTuple* Substring)

HTuple HTuple::TupleStrFirstN(const HTuple& Position) const

static void HOperatorSet.TupleStrFirstN(HTuple stringVal, HTuple position, out HTuple substring)

HTuple HTuple.TupleStrFirstN(HTuple position)

def tuple_str_first_n(string: MaybeSequence[str], position: MaybeSequence[Union[float, int]]) -> Sequence[str]

def tuple_str_first_n_s(string: MaybeSequence[str], position: MaybeSequence[Union[float, int]]) -> str

Description

tuple_str_first_ntuple_str_first_nTupleStrFirstNTupleStrFirstNtuple_str_first_n cuts the first characters up to position “n” out of each string of the input tuple StringStringStringstringValstring and returns them as new strings in the output tuple SubstringSubstringSubstringsubstringsubstring (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 PositionPositionPositionpositionposition. If PositionPositionPositionpositionposition only contains one element, this element contains the number “n”. If StringStringStringstringValstring and PositionPositionPositionpositionposition have got the same number of elements, the first element of PositionPositionPositionpositionposition determines the position “n” for the first string of StringStringStringstringValstring, the second element of PositionPositionPositionpositionposition does so for the second string of StringStringStringstringValstring and so on. If PositionPositionPositionpositionposition contains more than one element and StringStringStringstringValstring contains only one string, tuple_str_first_ntuple_str_first_nTupleStrFirstNTupleStrFirstNtuple_str_first_n cuts more than one substrings out of this string. The elements of PositionPositionPositionpositionposition 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_ntuple_str_first_nTupleStrFirstNTupleStrFirstNtuple_str_first_n returns an error.

If both input tuples are empty, the operator returns an empty tuple. Similarly, if StringStringStringstringValstring is empty and PositionPositionPositionpositionposition is not, the operator returns an empty tuple. In contrast, if PositionPositionPositionpositionposition is empty and StringStringStringstringValstring is not, an exception is raised.

Unicode code points versus bytes

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')set_system("tsp_tuple_string_operator_mode","byte")SetSystem("tsp_tuple_string_operator_mode","byte")SetSystem("tsp_tuple_string_operator_mode","byte")set_system("tsp_tuple_string_operator_mode","byte"). If 'filename_encoding'"filename_encoding""filename_encoding""filename_encoding""filename_encoding" is set to 'locale'"locale""locale""locale""locale" (legacy), this operator always uses the byte mode.

For general information about string operations see Tuple / String Operations.

HDevelop In-line Operation

HDevelop provides an in-line operation for tuple_str_first_ntuple_str_first_nTupleStrFirstNTupleStrFirstNtuple_str_first_n, which can be used in an expression in the following syntax:

Substring := str_firstn(String, Position)

Execution Information

• Multithreading type: independent (runs in parallel even with exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Processed without parallelization.

Parameters

StringStringStringstringValstring (input_control)  string(-array) → HTupleMaybeSequence[str]HTupleHtuple (string) (string) (HString) (char*)

Input tuple with string(s) to examine.

PositionPositionPositionpositionposition (input_control)  number(-array) → HTupleMaybeSequence[Union[float, int]]HTupleHtuple (integer / real) (int / long / double) (Hlong / double) (Hlong / double)

Input tuple with position(s) “n”.

SubstringSubstringSubstringsubstringsubstring (output_control)  string(-array) → HTupleSequence[str]HTupleHtuple (string) (string) (HString) (char*)

The first characters of the string(s) up to position “n”.

Alternatives

tuple_str_last_ntuple_str_last_nTupleStrLastNTupleStrLastNtuple_str_last_n, tuple_substrtuple_substrTupleSubstrTupleSubstrtuple_substr, tuple_strstrtuple_strstrTupleStrstrTupleStrstrtuple_strstr, tuple_strrstrtuple_strrstrTupleStrrstrTupleStrrstrtuple_strrstr, tuple_strlentuple_strlenTupleStrlenTupleStrlentuple_strlen, tuple_strchrtuple_strchrTupleStrchrTupleStrchrtuple_strchr, tuple_strrchrtuple_strrchrTupleStrrchrTupleStrrchrtuple_strrchr, tuple_splittuple_splitTupleSplitTupleSplittuple_split, tuple_environmenttuple_environmentTupleEnvironmentTupleEnvironmenttuple_environment

Module

Foundation

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ClassesClasses | | Operators