.. index:: single: string(Representation)
.. _string/1:

.. rst-class:: right

**object**

``string(Representation)``
==========================

* ``Representation`` - String representation. Valid values are ``atom``, ``codes``, and ``chars``.


String manipulation predicates supporting different string representations.

| **Availability:** 
|    ``logtalk_load(strings(loader))``

| **Author:** Paulo Moura
| **Version:** 1:1:0
| **Date:** 2026-04-17

| **Compilation flags:**
|    ``static, context_switching_calls``


| **Uses:**
|    :ref:`list <list/0>`

| **Remarks:**
|    (none)

| **Inherited public predicates:**
|    (none)

.. contents::
   :local:
   :backlinks: top

Public predicates
-----------------

.. index:: atom_string/2
.. _string/1::atom_string/2:

``atom_string/2``
^^^^^^^^^^^^^^^^^

Converts between an atom and a string.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``atom_string(Atom,String)``
| **Mode and number of proofs:**
|    ``atom_string(+atom,?text)`` - ``zero_or_one``
|    ``atom_string(-atom,+text)`` - ``zero_or_one``


------------

.. index:: number_string/2
.. _string/1::number_string/2:

``number_string/2``
^^^^^^^^^^^^^^^^^^^

Converts between a number and a string. Fails if the string does not represent a valid number.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``number_string(Number,String)``
| **Mode and number of proofs:**
|    ``number_string(+number,?text)`` - ``zero_or_one``
|    ``number_string(-number,+text)`` - ``zero_or_one``


------------

.. index:: string_chars/2
.. _string/1::string_chars/2:

``string_chars/2``
^^^^^^^^^^^^^^^^^^

Converts between a string and a list of characters.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``string_chars(String,Chars)``
| **Mode and number of proofs:**
|    ``string_chars(+text,?list(character))`` - ``zero_or_one``
|    ``string_chars(-text,+list(character))`` - ``zero_or_one``


------------

.. index:: string_codes/2
.. _string/1::string_codes/2:

``string_codes/2``
^^^^^^^^^^^^^^^^^^

Converts between a string and a list of character codes.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``string_codes(String,Codes)``
| **Mode and number of proofs:**
|    ``string_codes(+text,?list(character_code))`` - ``zero_or_one``
|    ``string_codes(-text,+list(character_code))`` - ``zero_or_one``


------------

.. index:: string_concat/3
.. _string/1::string_concat/3:

``string_concat/3``
^^^^^^^^^^^^^^^^^^^

Concatenates two strings.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``string_concat(String1,String2,String3)``
| **Mode and number of proofs:**
|    ``string_concat(+text,+text,?text)`` - ``zero_or_one``
|    ``string_concat(?text,?text,+text)`` - ``zero_or_more``


------------

.. index:: string_length/2
.. _string/1::string_length/2:

``string_length/2``
^^^^^^^^^^^^^^^^^^^

Returns the length of a string.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``string_length(String,Length)``
| **Mode and number of proofs:**
|    ``string_length(+text,?integer)`` - ``zero_or_one``


------------

.. index:: sub_string/5
.. _string/1::sub_string/5:

``sub_string/5``
^^^^^^^^^^^^^^^^

Extracts a substring from a string.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``sub_string(String,Before,Length,After,SubString)``
| **Mode and number of proofs:**
|    ``sub_string(+text,?integer,?integer,?integer,?text)`` - ``zero_or_more``


------------

.. index:: string_upper/2
.. _string/1::string_upper/2:

``string_upper/2``
^^^^^^^^^^^^^^^^^^

Converts a string to uppercase (ASCII only).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``string_upper(String,UpperString)``
| **Mode and number of proofs:**
|    ``string_upper(+text,?text)`` - ``zero_or_one``


------------

.. index:: string_lower/2
.. _string/1::string_lower/2:

``string_lower/2``
^^^^^^^^^^^^^^^^^^

Converts a string to lowercase (ASCII only).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``string_lower(String,LowerString)``
| **Mode and number of proofs:**
|    ``string_lower(+text,?text)`` - ``zero_or_one``


------------

.. index:: split_string/4
.. _string/1::split_string/4:

``split_string/4``
^^^^^^^^^^^^^^^^^^

Decomposes ``String`` into ``SubStrings`` according to separators ``SepChars`` and padding characters ``PadChars``. The string is split at the separators, and any padding characters around the resulting sub-strings are removed. Characters in both ``SepChars`` and ``PadChars`` are treated as separators where sequences count as one separator, and are ignored at string boundaries.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``split_string(String,SepChars,PadChars,SubStrings)``
| **Mode and number of proofs:**
|    ``split_string(+text,+text,+text,-list(text))`` - ``one``


------------

.. index:: atomics_to_string/2
.. _string/1::atomics_to_string/2:

``atomics_to_string/2``
^^^^^^^^^^^^^^^^^^^^^^^

Concatenates the atomic terms in ``List`` into ``String``. The list may contain numbers, atoms, and strings (in the current representation).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``atomics_to_string(List,String)``
| **Mode and number of proofs:**
|    ``atomics_to_string(++list(atomic),-text)`` - ``one``


------------

.. index:: atomics_to_string/3
.. _string/1::atomics_to_string/3:

``atomics_to_string/3``
^^^^^^^^^^^^^^^^^^^^^^^

Concatenates the atomic terms in ``List`` into ``String``, with ``Separator`` inserted between each element. The list may contain numbers, atoms, and strings (in the current representation).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``atomics_to_string(List,Separator,String)``
| **Mode and number of proofs:**
|    ``atomics_to_string(++list(atomic),+text,-text)`` - ``one``


------------

.. index:: trim/2
.. _string/1::trim/2:

``trim/2``
^^^^^^^^^^

Trims string by deleting all leading and trailing whitespace.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``trim(String,Trimmed)``
| **Mode and number of proofs:**
|    ``trim(+text,-text)`` - ``one``


------------

.. index:: trim/3
.. _string/1::trim/3:

``trim/3``
^^^^^^^^^^

Trims string by deleting all occurrences of the characters in ``Elements`` from the beginning and end of the string.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``trim(String,Elements,Trimmed)``
| **Mode and number of proofs:**
|    ``trim(+text,+text,-text)`` - ``one``


------------

.. index:: trim_left/2
.. _string/1::trim_left/2:

``trim_left/2``
^^^^^^^^^^^^^^^

Trims string by deleting all leading whitespace.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``trim_left(String,Trimmed)``
| **Mode and number of proofs:**
|    ``trim_left(+text,-text)`` - ``one``


------------

.. index:: trim_left/3
.. _string/1::trim_left/3:

``trim_left/3``
^^^^^^^^^^^^^^^

Trims string by deleting all occurrences of the characters in ``Elements`` from the beginning of the string.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``trim_left(String,Elements,Trimmed)``
| **Mode and number of proofs:**
|    ``trim_left(+text,+text,-text)`` - ``one``


------------

.. index:: trim_right/2
.. _string/1::trim_right/2:

``trim_right/2``
^^^^^^^^^^^^^^^^

Trims string by deleting all trailing whitespace.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``trim_right(String,Trimmed)``
| **Mode and number of proofs:**
|    ``trim_right(+text,-text)`` - ``one``


------------

.. index:: trim_right/3
.. _string/1::trim_right/3:

``trim_right/3``
^^^^^^^^^^^^^^^^

Trims string by deleting all occurrences of the characters in ``Elements`` from the end of the string.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``trim_right(String,Elements,Trimmed)``
| **Mode and number of proofs:**
|    ``trim_right(+text,+text,-text)`` - ``one``


------------

Protected predicates
--------------------

(no local declarations; see entity ancestors if any)

Private predicates
------------------

(no local declarations; see entity ancestors if any)

Operators
---------

(none)

