User Variables

*Tip:  There are three types of variables in vTask:     1) User Variables, such as %foo.   These are your variables.     2) System Variables, such as {clipboard}.   These are read-only values.     3) Environment Variables, such as %PATH%.   These are read-only operating system values.

General Overview of vTask Variables
If a script is anything more than a trivial job, it will most likely need to use variables. Variables are generally a "holder" for information. You can also think of them as a representation of other data. If you are not sure about the concept of variables, please refer to a basic programming documentation, there are many online tutorials concerning variables. Wikipedia has a good description of variables.

Here's a simple example of a variable in action:





In vTask, there are 3 types of variables:

      1) User Variables

• These are your variables
  
• You can name them anything you want (using A-Z, a-z, 0-9, and "_", "."), and they must begin with %
  
• They can be a subset of another variable: "%file" and "%filename" will not conflict
• You can set create them, change them, and delete them
  
• It is not necessary to "clean up" variables - they will be deleted automatically
  
• by default, all User Variables are Global (visible everywhere)
  
• Example: %foo, %my_data, %file[%loop]
  

      2) System Variables

• These are vTask internal variables
• They have a prefix and suffix { }, such as {loopcount}
• They are read-only (you can't change the values)
• They are meant to provide helpful and common data for automation scripts
• Common system variables are dates, times, computer information, and keyboard codes

      3) Environment Variables

• These are read-only operating system values (they are variables of Microsoft Windows)
• They have a prefix and suffix %, such as %PATH%
• They are case insensitive, %path% and %PATH% are the same
• They can be set using the Set Environment Variable action, however the changes you make are system-wide, so use caution
• You can view all Environment Variables by typing "SET" at any command prompt (start "cmd.exe")
• Common Environment Variables are program, folder, file, and Windows information

Additional features of vTask variables:

• Variable names are limited to 63 characters in length.
• You can set a variable's value to another's value, such as %foo = %fee (with the "Set Variable" action)
• Variables in vTask are "untyped". This means that a variable can contain string data (such as "abc") or numeric data (such as "123"), or both, and can switch between them whenever you want.
• There is no need to declare a variable ahead of time in vTask. As soon as you use the "Set Variable" action, the variable exists and is defined.
• An undefined variable is left as it is: "Hello %name" would show up as "Hello %name" if it had never been set (instead of being deleted and shown as "Hello ").
• vTask variables can be any size (single byte to hundreds of megabytes). vTask automatically allocates and reallocates memory to accommodate the size of the data.
• You can create variable arrays, such as %data[1], %data[2], etc. The array can be 0-based, 1-based, or anything else you want. You can reference the index using another variable, such as %filelist[%next] or %item[{loopcount}].
• To use a literal "%" when it's not part of a variable name, use a double percent: "%%"

*Tip:  See the Tools - Options screen for information regarding the persistence of variables with "Reset variables between runs".

Setting Variables with Action results
In the screen image below is an example of saving a name into a variable. The User Prompt action will ask the user for a value, and save it into the variable called "%answer" (it can be called anything). "%answer" can then later be used anywhere inside of another command, where it will be replaced with the value that the user typed. The input prompt and the properties for saving the value to a variable appear as follows:

*Tip:  There is no distinction made in vTask between numeric and text variables. They can be used interchangeably.

Setting Variables with Create/Set Action
There is no need to "declare" a variable in vTask before using it. Below is an example of using the System - Set Variable action to set a variable:




If you want to perform a math expression such as an increment:

%foo = %foo + 10

...use the following System action:




Erasing Variables
To erase a variable (set it to empty), use the System - Set Variable action with the "Set to Value" field empty.




Deleting Variables
To delete a variable, please refer to the Delete Variable System Action.


Variable Arrays
vTask provides a form of array storage for user variables. The basic syntax of an array is:   %variable [ index ]
Arrays in vTask are not 0-based or 1-based; you can start storing at any offset.

There are various ways to create and access array items, as illustrated in the following examples:



You can also fill up an array inside of a loop, and access the individual items later in your script: