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Business Logic / Control
Endlose Möglichkeiten in der Datenverarbeitung für Ihre Projekte.
Types of Control Functions
An overview of the types of functions distinguished within Control.
String Functions
These functions read and edit strings or parts of strings.
"clear" (string::clear)
Empties the string.

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Business Logic / Control
Endlose Möglichkeiten in der Datenverarbeitung für Ihre Projekte.
- Introduction to CTRL
  An introduction to the product's own programming language Control(CTRL).
- Control Classes
  The overview of classes available in Control.
- Types of Control Functions
  An overview of the types of functions distinguished within Control.
  - 32/64 bit Functions
  - Administration of Managers, Modules and Panels - Functions
  - Alert Handling Functions
    These functions are associated with datapoints and respond to alerts and changes to alerts.
  - AlertService Functions
    These functions provide alarm shelving, suppression, and out-of-service capabilities via the AlertServiceClient class.
  - Blob Functions
  - Communication functions
  - Connection Functions
    Connection functions can be used to establish connections to alerts, datapoints and system events.
  - Crypthographic Functions
  - Database Functions
  - Datapoint Functions
  - Error Functions
  - File Functions
    You can use these functions to import and export files, open, close files as well as perform other file manipulations.
  - Graphics Functions
  - Help Viewer Functions
    Available Functions for the Help Viewer.
  - HTTP Functions
  - Input Event Recorder Functions
  - Licensing Functions
  - Mapping Functions
  - Mathematical Functions
  - MindSphere Connector Functions
  - Miscellaneous Functions
  - Multilingual Functionality
    These functions are used for handling languages, texts and message catalogs in multilingual projects.
  - Project administration Functions
  - Query Functions
  - Redu/Dist Functions
  - Selection and Configuration Dialogs - Functions
  - Semaphore Functions
  - String Functions
    These functions read and edit strings or parts of strings.
    - "at" (string::at)
      Returns the character at the given index idx in the string.
    - "chop" (string::chop)
      Removes n characters from the end of the string.
    - "clear" (string::clear)
      Empties the string.
    - "contains" (string::contains)
      Returns true if this string contains an occurrence of the string s, otherwise false.
    - "count" (string::count)
      Returns the number of (potentially overlapping) occurrences of the string s in this string.
    - "endsWith" (string::endsWith)
      Returns true if the string ends with s, otherwise false.
    - "indexOf" (string::indexOf)
      Returns the index position of the first occurrence of the string s in this string.
    - "insert" (string::insert)
      Inserts the string s at the given index pos.
    - "isEmpty" (string::isEmpty)
      Returns true if the string is empty.
    - "lastIndexOf" (string::lastIndexOf)
      Returns the index position of the last occurrence of the string s in this string.
    - "left" (string::left)
      Returns a substring that contains the n leftmost characters of the string.
    - "length" (string::lenght)
      Returns the number of Unicode characters.
    - "mid" (string::mid)
      Returns a string that contains n characters of this string, starting at the specified pos index.
    - "remove" (string::remove)
      Removes n characters from the string, starting at the given pos index.
    - "replace" (string::replace)
      Replaces part of a string with a new one.
    - "right" (string::right)
      Returns a substring that contains the n rightmost characters of the string.
    - "split" (string::split)
      Splits the string into substrings wherever sep occurs, and returns the list of those strings.
    - "startsWith" (string::startsWith)
      Returns true if the string starts with s, otherwise false.
    - "subst" (string::subst)
      Substitutes the placeholders ($1 to $9) in a string with the specified arguments and returns the substituted string.
    - "toLower" (string::toLower)
      Returns a lowercase copy of the string.
    - "toUpper" (string::toUpper)
      Returns an uppercase copy of the string.
    - "trim" (string::trim)
      Removes whitespace from the start and the end.
    - "trimmed" (string::trimmed)
      This function produces a trimmed, new instance of a string.
    - dpValToString()
      This function converts the value specified in val into a string, with the format string of the datapoint element dp being used. If anytype is a dyn, then this function returns a dyn_string as the result.
    - patternMatch()
      Checks whether a string has a particular pattern.
    - sprintf()
      Formats a string.
    - sprintfPL()
      Formats a string. Like sprintf(), but change to the current WinCC OA language before converting.
    - sprintfUL()
      The function formats a string like sprintf()but changes to the current user language before formatting.
    - sscanf()
      Reads data from "s" and stores the data according to the "format" parameter into the additional arguments.
    - sscanfPL()
      Imports a string in formatted form. Like sscanf(), but changes to the current WinCC OA language before converting.
    - sscanfUL()
      The function imports a string in formatted form. The function works like the function sscanf() but changes to the current user language before reading the string.
    - strchange()
      Changes the content of a string at a specific index for a defined count of digits with a replacing string.
    - strexpand()
      Returns a formatted string.
    - strformat()
      Returns a formatted string.
    - strjoin()
      This function is used to combine elements of a dyn_string to one string.
    - strlen()
      Returns the length of a string in Bytes.
    - strltrim()
      Removes certain characters from a string, beginning from left.
    - strpos()
      Returns the position of a string within another.
    - strreplace()
      Replaces parts of a string with another string.
    - strrtrim()
      Cuts certain characters out of a string, starting from the right.
    - strsplit()
      Splits strings using delimiters.
    - strtok()
      Searches a string for the first occurrence of any of a set of bytes.
    - strtolower()
      Changes a string to lowercase.
    - strtoupper()
      Changes a string to uppercase.
    - substr()
      Cuts a string or a character of a certain length (in Bytes) out of another string.
    - uniDynPatternMatch()
      Checks whether particular strings in a dynamic field have a specific pattern.
    - uniFPrintf()
      Writes to a file.
    - uniFPrintfPL()
      Writes to a file similar to uniFPrintf() except changes to the current WinCC OA language before converting.
    - uniFPrintfUL()
      Writes to a file similar to uniFPrintf() except changes to the current Windows user language before converting.
    - uniSPrintf()
      Formats a string.
    - uniStrChange()
      Changes the content of a string at a specific index for a defined count of digits with a replacing string.
    - uniStrExpand()
      Returns a formatted string.
    - uniStrFormat()
      Returns a formatted string.
    - uniStrLen()
      Returns the length of a string.
    - uniStrPos()
      Returns the position of a string within another.
    - uniStrTok()
      Searches a string for the first occurrence of any of a set of characters.
    - uniStrToLower()
      Changes a string to lowercase.
    - uniStrToUpper()
      Converts a lower-case string to a string in capital letters.
    - uniSubStr()
      Cuts a string or a character of a certain length (characters) out of another string.
  - Funktionen für abonnementbasierte Lizenzen
    CONTROL-Funktionen zum Abfragen von Informationen aus abonnementbasierten Lizenzen.
  - System Tray
  - Time Functions
  - Threads Functions
  - User administration Functions
  - Vector / Dynamic arrays - Functions
  - Waiting Control Functions
    These Control functions block the execution of a script until a response is received from the Event Manager.
  - Window Functions
    This chapter lists all functions used to control windows and panels, such as ChildPanelOn, LayerOn, LayerOff, PanelOff, RootPanelOn, SwitchLayer, ZoomModule, and related dialog and module operations.
  - XML Control Extension Functions
    The XML Control Extension allows to operate on XML data via the CTRL scripting language.
- Control Graphics
- CONTROL Functions
- CtrlExtension
  Die CtrlExtension ermöglicht das Hinzufügen von benutzerdefiniertem C++-Code.
- CTRL-Debugger
  Der CTRL-Debugger ermöglicht ein Debuggen der Pogrammiersprache Control. Der Debugger kann über ein eigenes Panel verwendet werden, welches es auch erlaubt die Variablen zu beinflussen, Breakpoints zu setzen, usw.
- SQL in CONTROL
  Mit den Datenbankfunktionen besteht eine Möglichkeit, Werteabfragen von Datenpunkten und -elementen schnell durchzuführen.
- WinCC OA JavaScript Manager für Node.js
  Der WinCC OA JavaScript Manager für Node.js ist ein Manager, welcher die Einbindung der TypeScript/JavaScript Runtime-Umgebung in WinCC OA erlaubt.
- API Manager
  Das API von WinCC OA (Application Programming Interface) bietet eine Reihe von Funktionen, die es ermöglichen, dieses Prozessleitsystem um spezielle Manager zu erweitern.
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"clear" (string::clear)

Empties the string.

Synopsis

int string.clear();

Parameters


Parameter	Description
-	-

Description

Clears the string, making it empty.

Example

main()
{
  string s = "Alarm text";
  s.clear();
  DebugN(s);
  DebugN(s.isEmpty() ? "TRUE" : "FALSE");
}

Console output:

WCCOAui1:[""]
WCCOAui1:["TRUE"]

Assignment

String