Global Variables

How to define and use global variables.

@parent js/language

A variable is a place where you can store data so that you can use it later in your code. A global variable is accessible from every point in your code.

Block Editor

In the Block Editor, all variables are global. See Block Editor for info on creating global variables in a Block Editor script. The following block is used to set (assign) global variable's value:

The block below retrieves (gets) the current value of a global variable:

Touch Develop

In Touch Develop variables are either global or local. Variables have a name, a type, and value:

the name is how you'll refer to the variable
the type refers to the kind of value a variable can store
the value refers to what's stored in the variable

Global variables are variables that are available throughout your script. Unlike local variables, global variables are accessible across functions and in nested code blocks.

Create a global variable

To create a new global variable:

In the Touch Develop editor, click script (to the right of the search box).
Click + add new.
Click data-> data and then choose a type.
Enter a name for your global variable and click OK.

Set and use a global variable

To use a global variable that you've declared (using steps above):

In the Touch Develop editor, click data-> data or data-> + variable name.
Click := (assignment).
Click on the right-side of := and type or click what you want to store in the variable.

Your code should look something like this:

// global number variable

counter = 2

// global string variable

name2 = "Mike"

// global boolean variable

bool = true

(for info on creating image variables, see Image)

Once you've defined a variable and set it's initial value, use the variable's name whenever you need what's stored in the variable. For example, the following code gets the value stored in the global counter variable and shows it on the screen:

basic.showNumber(counter, 100)

To change the contents of a variable use the assignment operator :=. The following code increments counter by 10:

counter = counter + 10

Promote, demote, and extract

To promote a local variable to a global variable:

select the local variable name and click promote to data. The var keyword changes to the data symbol data->.

To demote a global variable to a local variable:

select the global variable name and click demote to var

To extract the content of a global variable to a local variable:

select the global variable name and click extract to var

See your global variables

To see a list of the global variables in your script:

click script (along the top) and scroll down to the vars heading

Lessons

counter, rotation animation, digital pet, offset image

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