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subtract

subtract number from [chunk of] ¬ container where container or chunk must contain a number.

The subtract command subtracts number from the specified container (or chunk) and puts the result into the container (or chunk), replacing what was there.

(You can use the is a operator to see if the container is a number.)

For example, if you say

subtract 3 from theTotal

and theTotal previously held 7, it will now hold 4.

Examples

subtract 4 from bkgnd field "total"

subtract last line of card field "debits" from item 1 of theTotal

if the Message box is a number then subtract 15 from Message box

Placeholders

number
An expression that evaluates to a number.

For example:

169 / 19
pi
(60.625 * 500)
average(1,4,5,10)
i+1 -- (where i is a number)
line 1 of fld "Debits"

Note: Formally, HyperCard distinguishes between factors (simple values) and expressions. The difference between factors and expression matters only if you like to drop parentheses. Most functions take factors as their parameters, which is why abs of -10 + 2 returns 12 and abs of (-10 + 2) returns 8. In short, always use parentheses to group things the way you want them to evaluate, and you won’t have to worry about the difference between factors and expressions.

container
HyperTalk DefinitionA place where you can store and retrieve a value.

There are six types of containers in HyperCard: a variable, a button, a field, the selection, the Message box, and menus.

myVariable
[the] selection
the Message box
btn 3
bg btn "Names"
card field 1
bkgnd field "Total"
menu 2
menu "Edit"

Additionally, you can refer to a button or field by its part number:

card part 1
last background part

AppleScript DefinitionAn object that contains one or more other objects, known as elements of the container. In a reference, the container specifies where to find an object. You specify containers with the reserved words of or in.

You can also use the possesive form ('s) to specify containers. For example, in

first window's name

the container is first window. The object it contains is a name property.

chunk
One of the following forms (or combinations thereof):

ordinal charactercharacter posInteger [to posInteger ]ordinal wordword posInteger [to posInteger ]ordinal itemitem posInteger [to posInteger ]ordinal lineline posInteger [to posInteger ]

For example:

first character
second item
middle line
character 1
char 1 to 10
word 3
item 5 to (the number of items of me)
line 1 to 10
char 1 to 10 of word 2 to 4 of ¬
line 3 to 6

A chunk combined with of and a container is called a chunk expression. For example:line 1 of card field "index"

Important: You can’t combine a stack name with a chunk expression—you can only refer to a chunk in the current stack.

subtract

Examples

Placeholders

Related Topics